B Y T

TRNG I HC DC H NI

PHM TH THU TRANG

TNG QUAN V

FARNESYLTRANSFERASE

V CC CHT C CH

FARNESYLTRANSFERASE

KHA LUN TT NGHIP DC S

H NI 2013

B Y T

TRNG I HC DC H NI

PHM TH THU TRANG

TNG QUAN V

FARNESYLTRANSFERASE

V CC CHT C CH

FARNESYLTRANSFERASE

KHA LUN TT NGHIP DC S

Ngi hng dn:

PGS.TS. Nguyn Hi Nam

Ni thc hin:

B mn Ha dc

H Ni 2013

LI CM N

Nhn dp hon thnh cun kha lun ny, cho php ti c by t lng bit

n su sc v knh trng ti nhng ngi tn tnh gip ti trong qu trnh

thc hin ti. Trc ht ti xin gi li cm n chn thnh v su sc nht n

PGS. TS. Nguyn Hi Nam cng cc thy c gio trong b mn ha dc tn

tnh gip ch bo, hng dn, ging dy cho ti nhiu kin thc qu bu trong

qu trnh hc tp, nghin cu v thc hin ti.

Ti cng xin gi li cm n cc thy c trong Ban gim hiu, Phng o to v

cc thy c gio trng i hc Dc H Ni dy d v gip ti trong sut

qu trnh hc tp ti trng.

Cui cng ti xin by t lng bit n su sc ti gia nh, bn b lun chia s,

ng vin, gip ti trong hc tp v trong cuc sng.

H ni, ngy 20 thng 5 nm 2012

Phm Th Thu Trang

MC LC

LI CM N

MC LC

DANH MC CC K HIU, CC CH VIT TT

DANH MC CC BNG

DANH MC CC HNH V, TH

T VN ....................................................................................................... 1

Chng 1: RAS V FARNESYLTRANSFERASE ......................................... 3

1.1. Protein RAS ................................................................................................ 3

1.1.1. Cu trc ca protein Ras....................................................................................... 3

1.1.2. Hot ng ca protein Ras ................................................................................... 4

1.1.3. t bin Ras ......................................................................................................... 7

1.2. Farnesyltransferase ................................................................................... 8

1.2.1. Cu trc ca Ftase ................................................................................................ 9

1.2.1.1 . Cu trc ca nhm Farnesyl .................................................................... 9

1.2.1.2. Cu trc ca Farnesyltransferase ............................................................. 9

1.2.2. Vai tr ca Farnesyltransferase .......................................................................... 10

Chng 2: MT S CHT C CH FARNESYLTRANSFERASE ......... 12

2.1. Cc cht c ch farnesyltransferase-trin vng trong nghin cu thuc

iu tr ung th ........................................................................................ 12

2.2. C s thit k cc cht c ch farnesyltransferase ............................... 14

2.3. Phn loi ................................................................................................... 14

2.3.1. Cc FTI c cu trc tng t vi FDP ...................................................... 15

2.3.2. Cc cht cnh tranh vi CAAX ................................................................. 16

2.3.3. Cc FTI tng t lng c cht (bisubtrate) ............................................. 18

2.3.4. Cc FTI khc .............................................................................................. 19

2.4. Cc FTI c th .......................................................................................... 20

2.4.1. R-115777 ................................................................................................... 20

2.4.1.1. Cu to ha hc .................................................................................... 20

2.4.1.2. Ngun gc, thit k, qu trnh nghin cu pht trin ........................... 20

2.4.1.3. S tng hp ...................................................................................... 24

2.4.1.4. Tc dng dc l .................................................................................. 25

2.4.2. Sch66336 ................................................................................................... 28

2.4.2.1. Cu to ha hc .................................................................................... 28

2.4.2.2. Ngun gc, thit kt, qu trnh nghin cu pht trin .......................... 29

2.4.2.3. S tng hp ...................................................................................... 31

2.4.2.4. Tc dng dc l .................................................................................. 32

2.4.2.5. Bin i Sch6633336 ........................................................................... 35

2.4.3. L-778,123 ................................................................................................... 35

2.4.3.1. Cu to ha hc .................................................................................... 36

2.4.3.2. Ngun gc, thit k, qu trnh nghin cu pht trin ........................... 36

2.4.3.3. S tng hp ...................................................................................... 36

2.4.3.4. Tc dng dc l .................................................................................. 37

2.4.4. BMS-214662 .............................................................................................. 39

2.4.4.1. Cu to ha hc .................................................................................... 39

2.4.4.2. Ngun gc, thit kt, qu trnh nghin cu pht trin .......................... 40

2.4.4.3. S tng hp ...................................................................................... 42

2.4.4.4. Tc dng dc l .................................................................................. 42

2.4.5. Cc FTI c ngun gc t nhin ................................................................. 46

KT LUN ......................................................................................................... 50

DANH MC TI LIU THAM KHO

CH GII CC CH VIT TT

1. ADME: absorption, distribution, metabolism, excretion - hp thu, phn b, chuyn

ha, thi tr.

2. AML: acute myeloid leukemia- bnh bch cu cp dng ty

3. AUC: area under curve- din tch di ng cong

4. DLT: c tnh liu ti a

5. DMSO: Dimethyl sulfoxide

6. DPI: di prenyltransferase inhibitor cht c ch hai prenyltransferase

7. FDP: farnesyl diphosphat

8. FTase: farnesyltransferase

9. FTI: farnesyltransferase inhibitor- cht c ch farnesyltransferase

10. GAP: GTPase-activating potein- potein hot ha GTPase

11. GDP: guanine-diphosphat

12. GEF: guanine nucleotide exchange factor- yu t kch thch ngoi bo

13. GGTase: geranylgeranyl transferase

14. GGTI: geranylgeranyl transferase inhibitor- cht c ch geranylgeranyl transferase

15. GTP: guanine-triphosphat

16. HOBt: 1-Hydroxybenzotriazole

17. IARC: International Agency for Research on Cancer- T chc ung th th gii

18. IC50: The half maximal inhibitory concentration- Nng c ch 50% hot ng

in vitro

19. In vitro: th nghim ngoi c th

20. In vivo: th nghim trong c th

21. Ki: h s c ch

22. MDS: hi chngmyelodysplastic

23. MTD: maximum tolerated dose liu ti a dung np c

24. NSCLC: Non-small-cell lung carcinoma- ung

25. SAR: structute activity relationship- mi tng quan cu trc, tc dng.

DANH MC CC BNG

Bng 2.1: Mi quan h gia cu trc-tc dng ca cc nhm th da trn khung l hp

cht 1 trong nghin cu SAR ca R-115777 ................................................................. 22

Bng 2.2: Hiu lc tc dng ca cc ng phn quang hc ca R-115777 ................ 24

Bng 2.3: S tng tc ca cc nhm th C-3 v N-4 trong nghin cu SAR ca BMS-214662 ....................................................................................................................................... 41

Bng 2.4: Kt qu d liu dc ng hc ca BMS-214662 trn cc bnh nhn ....... 45

Bng 2.5: S chn lc ca cc FTI c ngun gc t nhin vi FTase v GGTase ...... 47

Bng 2.6: Gi tr Ki ca mt s FTI c ngun gc t nhin ........................................ 48

DANH MC CC HNH V, TH

Hnh 1.1: V tr ca H-Ras trn NST 11. H-Ras v tr 15.5, t cp base 532.241 n cp

base 535.549 trn nhim sc th 11. ............................................................................... 3

Hnh 1.2: V tr ca N-Ras trn NST 1. N-Ras v tr 13.2, t cp base 115.247.084 n

cp base 115.259.514 ...................................................................................................... 4

Hnh 1.3: V tr ca K-Ras trn NST 12. K-Ras v tr 12.2, t cp base 25,358,179 n

cp base 25,403,853 ........................................................................................................ 4

Hnh 1.4: S bin i ca Ras ........................................................................................ 5

Hnh 1.5: S bin i t dng hot ng sang dng bt hot ca Ras ..................................... 6

Hnh 1.6: Cu trc ca protein Ras lin kt vi GTP .................................................... 6

Hnh 1.7: Hot ng ca Ras ......................................................................................... 7

Hnh 1.8: S prenyl ca cc protein kt thc bng mu CAAX, ER: endoplasmic

reticulum (li ni cht). ................................................................................................. 8

Hnh 1.9: Cu trc ha hc ca farnesyl ........................................................................ 9

Hnh 1.10: Farnesyltransferase, farnesyl diphosphat trong lin kt vi ion km ........ 10

Hnh 1.11: Phn ng farnesyl ho l bc u tin trong qu trnh dn truyn tn hiu

ca Ras sau phin m .................................................................................................... 10

Hnh 1.12: Phn ng c xc tc bi Farnesyltransferase ...................................... 11

Hnh 2.1: Cc FTI cnh tranh vi FDP c tng hp ............................................... 15

Hnh 2.2: Cc FTI cnh tranh vi CAAX ..................................................................... 17

Hnh 2.3: FTI c cu trc lng c cht ...................................................................... 19

Hnh 2.4: Cc FTI cha r c ch tc dng ................................................................. 19

Hnh 2.5: Cng thc cu to ca R115777 .................................................................. 20

Hnh 2.6: Trifluorophenylmethyl-quinolin b chuyn thnh quinolinon ...................... 21

Hnh 2.7: Cu trc ha hc ca miconazole v hp cht 1 ......................................... 22

Hnh 2.8: C nh 2 nhm clorophenyl v tr A v B, thay mt s nhm th trn khung

ca hp cht 1 tm ra hp cht hiu qu nht .......................................................... 23

Hnh 2.9: Mi quan h cu trc- tc dng trn khung R115777 .................................. 23

Hnh 2.10: S chn lc ca R115777 vi cc prenyltransferase ................................. 24

Hnh 2.11: S tng hp R115777 ............................................................................ 25

Hnh 2.12: Tc dng c ch s tng trng t bo ung th tuyn ty ca tipifarnib do c

ch G1, tc dng ph thuc liu s dng ...................................................................... 27

Hnh 2.13: Cng thc cu to ca lonafanib ............................................................... 28

Hnh2. 14:Sch-37370 v mt s cht thay i nhm th ........................................ 29

Hnh 2.15: Cu trc ca 2e, 2f ..................................................................................... 30

Hnh 2. 16: Cu trc ca 2g-2i v Sch66336 .............................................................. 31

Hnh 2.17: S tng hp SCH66336 ......................................................................... 32

Hnh 2.18: Tc dng ca Lonafarnib v paclitaxel khi s dng ring v khi kt hp trong

iu tr ung th bung trng ......................................................................................... 34

Hnh 2.19: Cng thc cu to ca L-778123 ............................................................... 35

Hnh 2.20: S tng hp L-778123 ........................................................................... 36

Hnh 2.21: S c ch FTase trong cc bnh nhn c iu tr bng L-778,123 ....... 38

Hnh 2.22: Cng thc cu to ca BMS-214662 .......................................................... 39

Hnh 2.23: M hnh tng tc ca cc imidazolylmethyltetrahydrobenzodiazepine vi

Ftase .............................................................................................................................. 40

Hnh 2.24: S tng hp BMS-214662 ..................................................................... 42

Hnh 2.25: Tc dng trn khi u khi s dng BMS-214662 ng ung trn cc mc

khi u HCT-116 trong m hnh chut b t bin suy gim min dch mang t bo ung th

ngi .............................................................................................................................. 43

Hnh 2.26: Kh nng c ch FTase cc t bo mu n nhn ngoi vi ca BMS-214662

....................................................................................................................................... 44

Hnh 2.27: Nng BMS-214662 trong huyt tngkhi tim tnh mch ..................... 46

Hnh 2.28: Mt s FTI .................................................................................................. 47

Hnh 2.29: S c ch FTase ca acid chaetomellic A v cht tng t acid zaragozic A

....................................................................................................................................... 48

1

T VN

Ung th l cn bnh gy t vong ng hng th hai trn th gii sau bnh tim

mch. l tn chung ch mt nhm gm khong 200 bnh do cc t bo phn chia

mt cch bt thng. m bo cc chc nng c th con ngi hot ng bnh

thng, mi c quan phi c mt s lng t bo nht nh. Trong cc bnh nhn ung

th, thay v tm ngh ngi, t bo s tip tc phn chia v thay v cht i, cc t bo s

tip tc sng, do lm lng t bo cc c quan tng ln t bin. Theo s liu iu

tra ca t chc ung th th gii (IARC), nm 2008 c khong hn 12,7 triu ca ung

th mi mc v 7,6 triu ca t vong v ung th [7,94]. Theo s liu ca cc khm cha

bnh-b y t, t 2002 n 2012 mi nm Vit Nam c 100000 n 150000 ngi mc v

75000 ngi cht do ung th.

Trong c th c hn 60 c quan khc nhau, bt k c quan no cng c th pht

hin ung th. Ung th c th pht trin t hu ht cc loi t bo trong c th, Mi c

quan thng c cu to bi mt s loi t bo khc nhau do mi c quan c th c

mt vi loi ung th. Tuy nhin c mt s loi ung th s ph bin hn cc loi khc.

Cho n nay, ung th vn c coi l mt trong cc bnh nan y trn th gii v l thch

thc ca nn y hc hin i [90]. Cc phng php iu tr ung th hin nay bao gm:

iu tr ti ch: phu thut, x tr v iu tr ton thn: ha tr. Cho n nay, c khong

200 thuc c cp php s dng trong lm sng v hng trm thuc vn ang c

nghin cu. Nhng thuc ny t c mt s thnh tu nh ci thin c tnh trng

bnh v ko di tui th bnh nhn tuy nhin vic s dng chng c nhiu hn ch do

c tnh cao, thiu tnh chn lc trn cc khi u v hiu lc iu tr thp [1]. Thm vo

, hu ht cc thuc iu tr ung th thng dng u c chung c ch v vy c tnh

cao v s khng thuc l mt thch thc ln. Ngy nay nh cc tin b v sinh hc phn

t, di truyn hc, ngi ta c nhng hiu bit ngy cng su sc v cc tin trnh sinh

hc trong ung th: s tng trng t bo, cc gen iu ha chu trnh t bo, s cht t bo

theo chng trnh, s to mch iu ny to iu kin thun li cc nh khoa

2

hc pht trin mt liu php mi: liu php iu tr nhm ch (targeted therapy). Phng

php ny ang ngy cng khng nh l mt bc i ng n nh vic ra i ca nhiu

thuc mi hiu qu hn, t tc dng ph hn v c tnh chn lc cao hn, mang li hy

vng cho nhng bnh nhn ung th. Mt s mc tiu phn t m cc thuc ang hng

n nh: protein kinase, s to mch, telomerase, farnesyltransferase, histon

deacetylase

Mt trong nhng mc tiu phn t ang c ch hin nay l cc enzym

farnesyltransferase (FTase). Nghin cu v cc FTase, ngi ta chng minh c rng

hot ng bt thng ca cc protein c farnesyl ha c lin quan n nhiu bnh ung

th. Trong nhng nm gn y, cc cht c ch FTase ang tr thnh cc tc nhn chng

ung th y trin vng. Trn th gii, c nhiu bo co v cc cht c ch FTase, tuy

nhin Vit Nam, vn ny cn kh mi m. V vy, chng ti tin hnh thc hin

ti Tng quan v farnesyltransferase v cc cht c ch farnesyltransferase vi

mong mun mang li nhng hiu bit tng qut nht v cc cht c ch

farnesyltransferase. ti ca chng ti gm nhng mc tiu sau:

1. Trnh by c nhng c im sinh hc c bn ca FTase ang c ng

dng trong nhng nghin cu v pht trin thuc iu tr ung th.

2. Trnh by c im ca mt s cht c ch FTase c nghin cu gn

y.

3

Chng 1: RAS V FARNESYLTRANSFERASE

1.2. Protein RAS

Hot ng ca cc t bo bnh thng trong sinh vt a bo c kim sot cht

ch bi mt mng li cc tn hiu phc tp, m bo cho cc t bo ch sinh sn khi c

th yu cu, v d nh trong qu trnh pht trin hay lm lnh vt thng. Ung th xy ra

khi s pht trin bnh thng b ph v, thng l do cc sai st trong dn truyn tn

hiu.

Protein Ras l nhm protein lin kt vi nucleotid ng vai tr then cht trong

kim sot s pht trin ca cc t bo bnh thng cng nh cc t bo t bin. Cc

nghin cu thc nghim v cu trc, chc nng v s iu ha protein Ras ch ra rng

chng l cha kho trung gian trong cc con ng dn truyn tn hiu iu ha s sinh

sn t bo cng nh tn hiu t cc receptor kinase, receptor kim sot rt nhiu qu trnh

ca t bo nh: s pht trin, bit ha, s cht theo chng trnh (apoptosis), t chc cu

to t bo v s vn chuyn qua mng [5,46].

1.1.1. Cu trc ca protein Ras

C 3 loi protein Ras bao gm H-Ras, N-Ras v K-Ras (gm K-Ras4A v K-

Ras4B). Cc protein Ras c 188 hoc 189 amino acid c trnh t tng ng: 86 amino

acid u ging ht nhau, 78 amino acid tip theo c 79% tng ng v cc amino acid

cui c trnh t khc nhau [42,46]. Cc protein Ras c vai tr khc nhau:

H-Ras: GTPase H-Ras l enzym bin i protein p21 ca ngi, c m ha

bi gen H-Ras nm trn cnh tay ngn ca NST 11 (hnh 1.1) [86].

Hnh 1.1: V tr ca H-Ras trn NST 11. H-Ras v tr 15.5, t cp base 532.241 n cp base 535.549 trn nhim sc th 11.

4

N-Ras: GTPase N-Ras l mt enzym ngi c m ha bi gen N-Ras, n

l mt oncogen (gen c kh nng gy ung th) m ha cho protein mng t

bo, di chuyn qua li gia b my Golgi v mng sinh cht. Gen N-Ras nm

trn cnh tay ngn ca NST s 1 (hnh 1.2) [88].

Hnh 1.2: V tr ca N-Ras trn NST 1. N-Ras v tr 13.2, t cp base 115.247.084 n cp base 115.259.514

K-Ras: GTPase K-Ras l enzym ngi c m ha bi gen K-Ras nm trn

cnh tay ngn ca NST 12. K-Ras tham gia vo iu chnh s phn chia t bo

bng cch vn chuyn cc tn hiu t ngoi bo vo nhn, l mt phn ca con

ng RAS/MAPK C 2 loi K-Ras l K-Ras4A v K-Ras4B (hnh 1.3) [87].

Hnh 1.3: V tr ca K-Ras trn NST 12. K-Ras v tr 12.2, t cp base 25,358,179 n cp base 25,403,853.

1.1.2. Hot ng ca protein Ras

Protein Ras c tng hp nh protein a nc trong cc ribosome t do trong t

bo cht (Pro-Ras) [75]. dn truyn cc tn hiu ngoi bo thu c t cc yu t sinh

trng v cc cytokin, Ras phi gn vi mt trong ca mng sinh cht. Vic ny c h

tr bi mt chui cc bin i ha hc sau phin m. Sau khi to thnh Pro-Ras trong t

bo cht, Ras tip tc c bin i qua nhiu qu trnh ni tip nhau: u tin l phn

ng farnesyl ha ca phn cystein; tip n l phn ng thy phn ct chui peptid AAX

(A l amino acid bo bt k, X l amino acid bt k) bi protease; v cui cng l phn

5

ng methyl ha u tn cng C (C-terminal) bi enzym carboxylmethyl transferase. Phn

ng farnesyl ha l phn ng quan trng nht ca qu trnh ny [12,48].

Hnh 1.4: S bin i ca Ras: sau khi c tng hp Ribosome, Ras c gn thm nhm prenyl t bo cht, sau chuyn vo li ni cht, y xy ra qu trnh thy phn ct chui AAX, ri n phn ng methyl ha u tn cng C (C-terminal) bi enzym carboxylmethyl transferase, cui cng Ras lin kt cng ha tr vi acid bo v c vn chuyn n mng t bo.

Cc protein Ras dn truyn tn hiu ngoi bo t cc receptor b mt t bo vo

trong t bo bt u qu trnh chuyn ha ca protein kinase. iu kin bnh thng,

Ras lin kt vi GDP (Ras-GDP) l trng thi khng hot ng nhanh chng c

chuyn i thnh Ras-GTP l trng thi hot ng p ng vi cc kch thch ngoi

bo, bao gm: cc yu t tng trng- kch thch s tng trng ca nguyn bo si, cc

yu t tng trng kch hot lympho- kch thch s gia tng ca t bo to mu, hormon

v cc cht dn truyn thn kinh (hnh 1.5) [26,36].

6

Hnh 1.5: S bin i t dng hot ng sang dng bt hot ca Ras. Khi lin kt vi GTP, Ras tr thnh dng hot ng, GTPase loi 1 nhm Phosphoryl (Pi) chuyn Ras v dng khng hot ng.

Hnh 1.6: Cu trc ca protein Ras lin kt vi GTP

Cc GTPase Ras iu ha s phn chia t bo thng qua p ng vi s kch thch

ca cc yu t tng trng. Cc yu t tng trng gn vi receptor mng sinh cht, sau

khi c hot ha, cc receptor kch thch s truyn tn hiu bn trong t bo, cc tn hiu

truyn tin th 2 t bn ngoi t bo vo nhn t bo gy ra p ng, lm t bo pht trin

hoc phn chia. GTPase Ras l tn hiu sm trong nhiu con ng truyn tin, n gn

7

c vi mng t bo l do s c mt ca nhm isoprenyl u tn C. V d nh hot

ng ca H-Ras (hnh 1.7).

Hnh 1.7: Hot ng ca H-Ras

1.1.3. t bin Ras

Trong s khong 30% bnh ung th, c bit chim t l ln l ung th ty v ung

th rut kt, c s to thnh protein Ras t bin, lun tn ti trng thi hot ng, do

khng kim sot c cc tn hiu tng trng [22].

cc t bo bnh thng th cc yu t tng trng ngoi bo kch thch lin tc

s duy tr Ras trng thi hot ng (Ras-GTP), lm vn chuyn tn hiu ti cc protein,

nu khng Ras nhanh chng chuyn v dng khng hot ng( Ras-GDP). Trong cc t

bo c t bin Ras, Ras khng quay li dng lin kt vi GDP m vn trng thi lin

kt vi GTP v kch hot lin tc s sinh sn ca t bo mc d khng c s kch thch

ca yu t tng trng [22].

Trong cc khi u khc nhau thng c t bin 1 gen Ras: t l t bin K-Ras l

cao nht, ch yu trong ung th tuyn ty (90%), rut kt (50%) v phi (30%). Gen N-

ras ch yu gy t bin trong bnh bch cu (30%). i vi tr em, t bin N-Ras

codon 12 hoc 13 c cho l 1 yu t lm tng nguy c ti pht bnh bch cu lympho

8

cp. T l t bin gen H-Ras l thp nht. Tuy nhin ch t bin gen Ras l khng

cho mt bin i c tnh, khi u ch xut hin khi c nhiu sai khc trong di truyn [6].

1.2. Farnesyltransferase

a s cc phn ng prenyl ha c xc tc bi cc prenyltransferase, chng gn

cc nhm isoprenoid: 15-carbon-farnesyl hoc 20-carbon-geranylgeranyl. 2 trong 3

prenyltransferase: farnesyltransferase v geranylgeranyl transferase-I c th hot ng

trn cc protein kt thc bng mu CAAX (C: cystein, A l amino acid bo bt k, X l

amino acid bt k) nh: Ras, RhoB, RhoE, lamin A v lamin B. Chng l 2 heterodimer

c 1 tiu n v ging nhau v 1 tiu n v khc nhau [27].

FTase u tin cho cc protein kt thc l methionin (M) hoc serin (S) cn

GGTase-I u tin cho cc protein kt thc l mt leucin (L). H-Ras ch b bin i bi

FTase cn N-Ras v K-Ras s b bin i bi GGTase khi FTase b c ch (hnh 1.8)

[13].

Hnh 1.8: S prenyl ca cc protein kt thc bng mu CAAX, ER: endoplasmic reticulum (li ni cht).

Cc nghin cu gn y c thc hin vi mt lng ln cc cht c ch

farnesyltransferase (FTI) tm hiu v ph tc dng cng nh hiu r hn c ch

sinh hc ca chng. Kt qu cho thy cc FTI cn c tc dng trn cc khi u khng phi

9

do t bin Ras. Hin nay, c ch tc dng ca FTI rt phc tp v cha c hiu ht

[40].

1.2.1. Cu trc ca FTase

1.2.1.1. Cu trc ca nhm farnesyl

Nhm farnesyl gm 3 nhm isopren, mi nhm c 5 carbon (hnh 1.9). Nhm

farnesyl ny s c gn vo Pro-Ras bin i thnh Ras.

Hnh 1.9: Cu trc ha hc ca farnesyl

1.2.1.2. Cu trc ca farnesyltransferase

Farnesyltransferase l mt metalloenzym km, gm 2 tiu n v c cu trc

tng t nhau: v . Tiu n v gm 378 amino acid [45,63]. u tn N, n c 7

cp amino acid i song c cu trc xon alpha to thnh hnh lim [68]. Trong vng

xon ny, v tr ca asparagin, arginine, tryptophan v glutamat c gi c nh. S bt

bin ca tryptophan c cho l c lin quan n vic lin kt vi tiu n v beta

[57,81]. Trong tiu n v beta cu trc cng c lp i lp li nhng phenylalanin c

gi c nh. Tiu n v beta c cha km v 437 amino acid to thnh cu trc xon bt

thng. Ion km cng cc aminoacid xung quanh n to thnh mt in trng lin

kt vi farnesyldiphosphat (hnh 1.10) [42].

10

Hnh 1.10: Farnesyltransferase, farnesyl diphosphat trong lin kt vi ion km

1.2.2. Vai tr ca farnesyltransferase

Farnesyltransferase (FTase) xc tc cho phn ng farnesyl ha bng cch nhn

dng mu CAAX u tn cng C ca Ras v chuyn 15-carbon farnesyl isopenoid t

farnesyl diphosphat (FDP) ti kt hp vi cystein ca Ras to thnh thioete (hnh 1.11)

[57,81], sau ui AAX s b thy phn. FTase chn lc cc protein c X l methionin

(M) hoc serin (S).

Cys A1

SH

A2 X

OP

O

OO

P

O

O

O

Ras

Farnesyl diphosphate (FDP)

Cys A1

S

A2 XRasFTase

Hnh 1.11 : Phn ng farnesyl ho l bc u tin trong qu trnh dn truyn tn hiu ca Ras sau phin m

Ion km

Nhm

farnesyl

diphosphat

11

y l bc quan trng trong qu trnh hot ha Ras

Hnh 1.12: Phn ng c xc tc bi farnesyltransferase.

Gen Ras thng b t bin trong cc khi u hn cc gen khc, do cc protein

c m ha bi gen ny c coi l mc tiu iu tr nhm ch t khi c pht hin.

Tuy nhin, sau 30 nm nghin cu, khng c thuc iu tr nhm ch protein Ras no

c pht trin thnh cng trong nghin cu thuc iu tr ung th. Tht vy, cc khi u

c t bin Ras vn l cc khi u kh iu tr v loi b bng phng php iu tr nhm

ch [66]. Nh trnh by trn, Ras c tng hp dng cha hot ng (Pro-Ras).

chuyn thnh dng hot ng n phi tri qua mt chui bin i, trong phn ng

farnesyl ha c xc tc bi enzym FTase l phn ng u tin v quan trng nht.

Theo , FTase b c ch s ngn s bin i Ras thnh dng hon chnh, c kh nng

hot ng. FTase c xem nh mc tiu iu tr tim nng cho cc bnh ung th do t

bin Ras. Cc FTI ang c nghin cu, mt s hp cht c a vo th nghim

lm sng v cho kt qu ha hn [62].

12

Chng 2: MT S CHT C CH

FARNESYLTRANSFERASE

2.5. Cc cht c ch farnesyltransferase-trin vng trong nghin cu thuc

iu tr ung th

Nghin cu trong cc khi u c t bin H-Ras cho thy cc cht c ch

farnesyltransferase ngn chn s farnesyl ca Ras trong cc t bo ung th ca cc m

nui cy [59, 74]. Trong cc th nghim tin lm sng, cc FTI cho thy hiu lc ng

k trong vai tr 1 thuc chng ung th. Gi tr IC50 ca cc FTI dng phn t nano c

nng rt thp vi cc c cht l H-Ras hoc K-Ras. Thm vo , mt lng ln cc

t bo ung th rt nhy cm vi cc FTI [21,64].

Cc tc nhn ny c ch s farnesyl hiu qu hn s geranylgeranyl ca protein

Ras, n cng c kh nng c ch s farnesyl ca 1 s protein khng phi l c cht ca

FTase, khi cn nng FTI cao hn, c bit l khi c ch s farnesyl ca lamin B

[24,59]. Khi s dng FTI, cc t bo ung th c t bin H-Ras thng b c ch hon

ton trong khi cc t bo c t bin N-Ras v K-Ras thng c kh nng sng st cao

hn. Nagasu v cng s so snh s c ch cc khi u trong chut mang t bo ung th

ngi (xenograft) ca 3 dng t bo: EJ-1 (ung th bng quang), HT1080 (fibrosarcoma)

v HCT116 (ung th rut kt) tng ng th hin t bin H-Ras, N-Ras v K-Ras bi

FTI B956/B1086. Kt qu l nhy cao nht vi cc t bo c t bin H-Ras, sau l

cc t bo c t bin N-Ras v cui cng l cc t bo c t bin K-Ras [51]. Nguyn

nhn c th l do khi s farnesyl b c ch, cc t bo c t bin N-Ras v K-Ras c kh

nng thot c ch do chng chuyn sang b geranylgeranyl ha bi GGTase-I [32,33]. N-

Ras v K-Ras c th c bin i bi c FTase v GGTase, s geranylgeranyl ch tr

nn quan trng khi s farnesyl b c ch. Hoc c th do H-Ras c i lc vi FTase cao

hn K-Ras v N-Ras. Do c th d on l cc FTI hiu qu trong iu tr cc khi u

c t bin H-Ras hn cc khi u c t bin N-Ras v K-Ras. Tuy nhin, ng ch l

1 s dng t bo khng mang t bin Ras cng nhy cm vi cc FTI [64].

13

Mijimolle v cng s s dng phng php di truyn nghin cu tc dng

khng khi u ca cc FTI bng cch to ra ri tm iu kin loi tiu n v ca

FTase trong chut. Trong m hnh ny, c th thy s xut hin ca FTase quyt nh s

pht trin ca khi u mc d s bin i ca t bo t dng bnh thng sang dng c tnh

khng i hi cc protein b farnesyl ha, ngoi ra s cn bng ni mi ca con ngi

cng khng b cn tr bi s thiu ht FTase [49]. Nhng quan st ny cho thy cc FTI

cn th dng nh l tc nhn ha hc phng v h tr iu tr ung th. Tuy nhin c

ch tc dng ca FTI vn cha r rng do cha xc nh c c ch c ch s pht trin

ca khi u.

Cc pht hin cho thy trong nhng iu kin nht nh, cc FTI c th c ch s

pht trin ca khi u bng cch thc y qu trnh apoptosis (s cht theo chng trnh),

liu mc tiu phn t chnh l Ras hay 1 protein khc cng tri qua s farnesyl? Mc tiu

ny c th l RhoB, protein tham gia vo s lin kt v cng tri qua s farnesyl. C th

cc FTI ngn chn tn hiu ca RhoB, tn hiu lm cc t bo b t bin v tip tc sng

[41].

Thm ch c bng chng cho thy nu c cc t bin oncogen Ras, cc t bo c

tnh vi nhiu bt thng gen c th nhy cm vi cc FTI. Oncogen H-Ras khng c

farnesyl ha s to thnh phc hp vi Raf, ngn cn s di chuyn ca n t t bo cht

n mng t bo. Tuy nhin 1 phi-oncogen Ras c farnesyl ha nn n khng tng

tc vi Raf. Do cc t bo vi oncogen Ras c th nhy cm vi FTI hn cc t bo

bnh thng [50]. Tuy nhin, s c ch khng hon ton FTase s to ra oncogen Ras

lm c ch Raf trong cc t bo khi u c t bin Ras, trong khi hot tnh ca Raf trong

cc t bo bnh thng khng b nh hng.

14

2.6. C s thit k cc cht c ch farnesyltransferase

Nh cp trn, Ras c to thnh t bo cht v chuyn thnh dng

hot ng, bc u tin v quan trng nht l s farnesyl ca cystein ca nhm CAAX

u tn C, sau nhm AAX b phn ct ct bi Ras-converting enzym I cn cysteine

c farnesyl ha v carboxymethyl ha bi isoprenylcysteine carboxyl

methyltransferase [60]. Nh s bin i ny (H-Ras, N-Ras, v K-Ras 4A) hoc nh c

cc nguyn t hydro linh ng ( K-Ras 4B), cc protein Ras c gn vo mng t bo

[29]. Sau , Ras lin kt vi GTP s chuyn thnh dng hot ng. S farnesyl ca

cystein u tn cng C bi enzym FTase l cn thit cho chc nng ca Ras, do

FTase c th l 1 ch tc dng cho cc can thip. FTase c 2 v tr lin kt: 1 v tr

nhn dng farnesyl pyrophosphat v 1 v tr cho CAAX ca protein [44]. Cc nghin cu

tm ra cu trc tinh th ca FTase ngi v d on rng trong cc tetrapeptid CAAX

tng t, ch cc peptid c valine hoc isoleucin A2 c farnesyl ha. Vic tm ra cu

trc tinh th cng ch ra rng t bin amino acid 12 (do s i ch ca glycine) dn u

trong nh hng khng gian trong thy phn GTP. Glutamin v tr 61 l 1 v tr quan

trng trong xc tc phn ng ca GTPase. Do t bin cc v tr ny nh hng n

hot ng ca cc enzym [37]. Da trn nhng pht hin ny, cc cht c ch

peptidomimetic ca FTase c thit k.

2.7. Phn loi

Da vo cu trc, c ch hot ng, cc FTI c chia thnh 4 loi:

Cc FTI c cu trc tng t FDP: acid (-hydroxyfarnesyl) phosphonic, dn

xut ca acid -ketophosphonic, -hydroxyphosphonic v J-104871

Cc FTI c cu trc tng t CAAX: BZA-5B, BZA-2B,L-731,734, L-731,735,

L-739,749, L-739,787,L-739,750, L-744,832 B581, Cys-4-ABA-Met v Cys-

AMBA-Met, FTI-276, FTI-277, B956 v dn xut methyl este B1096, RPR-

115135

15

Cc FTI lng c cht: cc cht tng t acid phosphonic, cc cht c ch

phosphonat: BMS-185878, BMS-186511 v BMS-184467, dn xut acid

phosphinyl v dn xut ca acid hydroxamic.

Cc FTI khc c ngun gc t nhin: acid chaetomellic, acid actinoplanic A v

cc cht tng t manumycin

2.7.1. Cc FTI c cu trc tng t vi FDP

Cc FTI loi ny c thit k da trn phn farnesyl ca c cht FDP thit k

cc FTI c cu trc tng t FDP (hnh 2.1). Cc FTI loi ny s cnh tranh vi FDP

gim phn ng farnesyl ha ca Ras bng cch gn vi FTase v tr gn ca FDP. -

hydroxyfarnesylphophat l cht gc ca nhm ny, da vo cu trc ca hp cht ny

tng hp cc dn xut mi c kh nng c ch FTase chn lc hn [42].

O P

O-

O

O P O-

O-

O

P

OH

OH

OHO

O

P

FF

ONa

ONa

O

O P O

O-

O

P O-

O-

O

NH

P

O

CO2Na

ONa

O

ONa

O

HN

P

O

ONa

ONa

O

O

HN

P

O

ONa

O

O O

O

FPP

(a -Hydroxyfarnesyl)phosphonic AcidFPPA 1

Difluorinated b-Ketophosphonic Acid Compound I

Compound II Compound III Hnh 2.1: Cc FTI cnh tranh vi FDP c tng hp

Trong cc FTI u tin th hin hot tnh trong h thng t bo nui cy, FDP

khng th b thy phn: acid -hydroxyfarnesyl-phosphonic c ch FTase vi h s c

ch (Ki) = 5 nM/L [42, 34]. Tc nhn ny c ch qu trnh Ras trong cc nguyn bo si

t bin H-Ras NIH3T3 nng thp 1M/L [56]. Cc cht tng t FDP thng c

chn lc cao, c ch FTase nng di micromol trong cc th nghim in vitro

c tng hp v cho thy kh nng c ch qu trnh H-Ras trong cc t bo nng

16

xp x 1 M/L [42, 34]. Cc cht tng t FDP chng minh l ngn chn s vn

chuyn H-Ras-mediated ca nguyn bo si NIH 3T3 nng 100 M/L v khng gy

c vi cc t bo khng b t bin nng ln n 250 M/L [42]. Tuy nhin, cc

tc nhn ny cha chng minh c mi lin quan vi hot ng chng ung th trong m

hnh ng vt.

Mc d FDP lin kt vi t bo bng i lc rt nh, nng FDP trong t bo xp

x 1 M/L, ngha l cc lin kt FDP vi FTase b chim gi ht. Nh vy, cc cht

tng t FDP cn c i lc vi FTase cao hn FDP. Hn na, cc enzym khc cng s

dng FDP trong nhiu qu trnh ca t bo, ngha l cc cht tng t FDP c th gy ra

c tnh ng k v do cc hp cht c th s dng trong lm sng cn c chn lc

k.

2.7.2. Cc cht cnh tranh vi CAAX

Cc nghin cu ch ra rng tetarpeptid CAAX cha yu t chnh nhn ra

enzym FTase, do dn n tng hp mt s peptid l cht c ch FTase bng cch s

dng nguyn tc thit k thuc: to ra cc FTI cnh tranh vi CAAX trong lin kt vi

prenyltransferase (hnh 2.2). Vic chng minh cc tetarpeptid c thay th cc

aminoacid thm v tr acid bo th 2 t cystein to ra cc FTI kch thch cho s pht

trin cc peptidomimertic phn t lng thp c xem l chin lc chnh pht trin

cc FTI [10, 70].

17

O

HN

NH

H2N

HSO

O

HN

S

OH

O

CVIM

NH

HN

HS

H2N

O

Compound 32

N

N

Cl

N

OSCH 44342

N

N O

HN

S

OR

O

N

O

HS

H2N

BZA 2B, R = H

BZA 5B, R= CH3

O

O

HN

SO2CH3

OR

OHN

HS

H2N

L= 739,749, R= CH3L= 739,750, R= H

L= 744-832, R= CH(CH3)2

O

HN

S

OR

OHS

H2N

B= 956, R = H

B = 1086, R = CH3

NH

O

HN

S

OH

OHN

HS

H2N

B = 583

HN

HS

H2N

FTI = 276, R= O

FTI = 277, R= OCH3

O

HN

S

R

O

Hnh 2.2: Cc FTI cnh tranh vi CAAX

Mc d cc cht tng t peptid CAAX l cc FTI mnh trong h thng th

nghim in vitro, mt s yu t l ha lm gii hn tc dng chng li s pht trin ca

cc t bo khi u trong cc m nui cy v trong ng vt. Cc hp cht ny c kh nng

thm vo mng km v khng n nh, do chng thng mt 2 hoc 3 phn hiu lc

trong cc t bo. u tin, u carbon t do ca CAAX gi c tch in (-) lm cho

mng t bo khng thm cc hp cht ny. che giu in tch (-), mt tin cht c

s dng tng hp dng este hoc dn xut lacton, vi gi thit l dng este hoc lacton

s c thy phn trong t bo thnh dng acid c hot tnh cao hn. Tuy nhin, cc tin

cht ny d b phn ct bi esterase v cc enzym thy phn khc trong huyt tng, do

thch thc t ra l thit k c cc tin cht khng c s thy phn trong huyt

tng nhng vn d dng b thy phn trong t bo to ra cc FTI c hot tnh mnh.

Mt yu t th 2 l cc lin kt peptid ca cc hp cht ny khng n nh, chng

nhanh chng b thy phn bi protease ni bo v i hi phi c nhng bin i ha hc

b sung tng cng n nh ca hp cht. Trong phng php pseudopeptid

18

(peptid gi), cc lin kt peptid trong CAAX gim xung dng methylenamino ca

chng c s dng to ra peptidomimetic mnh v n nh

Mt phng php mi hn pht trin cc FTI peptidomimetic l xa b X trong

mu CAAX, sau sa thm cc yu t u tn C [17]. Phng php ny to ra cc

hp cht thm c vo cc t bo, l cht c ch cnh tranh thun ty ca c cht

protein nhng khng phi c cht ca FTase. Trong nghin cu in vitro, cc tc nhn ny

cng nh hng mnh n cc FTase nng 25-500 nM/L, thm vo , cc

pseudopeptid chn lc vi FTase hn GGTase-I 100 ln. S pht trin ca cc tc nhn

ny c gii hn bi c ch khng gy c vi t bo.

Mt phng php khc l thay th cc tnh nng peptid ca hai amino acid trung

tm ca tetrapeptid CAAX vi phn k nc n nh.

Cc FTI loi ny c chia thnh 2 loi da vo cu trc:

Cc hp cht c cu trc peptidomimetic

Cc hp cht khng c cu trc peptidomimetic

2.7.3. Cc FTI tng t lng c cht (bisubtrate)

Phn tch cu trc v ng hc ca FTase cho thy mt c ch tun t, theo ,

mt enzym -FDP-CAAX a bc phc tp c c hnh thnh trc khi xc tc v tng

kh nng cc cht tng t lng c cht bt chc trng thi chuyn i ca enzym c

th l cht c ch enzym va mnh va chn lc. Ngoi ra, cc cht tng t lng c

cht kt hp cu trc ca FDP v tetrapeptid CAAX chn lc vi FTase nhiu hn so vi

GGTase 2000 ln v c tc ng ti thiu ln t bo bnh thng. Cc hp cht ny cng

c ch tn hiu Ras v s pht trin ca cc t bo H-Ras v K-Ras t bin NIH-3T3

nng thp 0,1 M/L, hu ht s farnesyl ca Ras b c ch hon ton liu 100 M/L.

Hn na, cc tc nhn ny cho thy kh nng c ch s tng trng c lp ca ST88-14,

mt dng t bo schwannoma c tnh do s thiu ht biu hin ca neurofibromin[79].

Bi cc neurofibromin hot ha Ras GTPase, cc t bo thiu n dn n tng mc Ras-

GTP, c th cc cht c ch ca FTase s c tc dng iu tr cc bnh nhn

neurofibromatosis loi 1 [2].

19

Hnh 2.3: FTI c cu trc lng c cht

2.7.4. Cc FTI khc

Mt s FTI khc c xc nh bng cch sng lc mt lng ln cc sn phm t

nhin hoc t cc hp cht c ch FTase xc tc s gn FDP kt hp vi H-Ras trong

nghin cu in vitro. Sng lc ngu nhin cc sn phm t nhin v t vi sinh vt bng

cch s dng gen ca nm men cc cht c ch Ras thm vo trong t bo, dn n

xc nh manumycin (1 FTI) t cc sn phm ca vi sinh vt v cc cht lin quan nh l

cht c ch FTase [72]. Mt s sn phm t nhin bao gm acid chaetomellic, acid

actinoplanic A v cc cht tng t manumycin cnh tranh vi FDP, trong khi cc cht

c ch khc nh cc pepticinnamid cnh tranh vi tetrapeptid CAAX (hnh 2.4) [42].

Cc tc nhn ny c ch FTase ngi IC50 vo khong 100nM/L.

HO

O

CO2H CH2OH

OCH3

HO

CH3

OHO O

H3C

OO

CH3

H

H3C

HCH3

CH3CH3

O

NORO

O

CH3

H

CH2OH

SS

OHO

H3C

O O

OCH3

O

O

OO

O

O

O

H O

O

OH

ON

N

H3CO

H2NCOOH

CH3H2N

OH

H3CO

H

O

O

HN

ON

OClN

O

O

O

NHHN

O

O

OH

OHOCH3

Acid BarceloneicCylindrol A

Preussomerin G

Glitoxin, R=HAcetylglitoxinR=COCH3

SCH 58450

Patulin

10'- DesmethoxystreptonigrinPepticinnamin E

Hnh 2.4: Cc FTI cha r c ch tc dng

2.8. Cc FTI c th

20

Cc FTI tetra-peptid v peptidomimetic c thit k, tng hp t rt sm

nhng chng nhanh chng tht bi trong th nghim in vivo do cc c tnh dc ng

hc, sinh kh dng ca thuc khng t [19].

2.8.1. R-115777

R-115777 (Tipifarnib, Zarnestra) l mt FTI khng c cu trc peptidomimetic,

mt trong hai FTI ng ung trin vng nht v ang c th nghim lm sng pha III

[93].

2.8.1.1. Cu to ha hc

Khi lng phn t: 489.4

Cng thc phn t: C27H22Cl2N4O

N O

CH3

Cl

N

N

CH3

Cl

H2N

Hnh 2.5: Cng thc cu to ca R-115777

Danh php IUPAC: (R)6-amino [(4-chlorophenyl) (1-methyl-1H-imidazol-5-

yl)methyl]-4-(3-chlorophenyl)-1-methyl-2(1H)-quinolinon

2.8.1.2. Ngun gc, thit k, qu trnh nghin cu pht trin

Hng dc phm Janssen tham gia vo nghin cu thuc tc dng ti ch Ras vi

nghin cu tc dng chng ung th ca cc thuc chng nm ketoconazol c ch 14-a-

demethylase [16]. Gi thuyt t ra l ketoconazol tc dng ln chc nng ca Ras khng

phi bng cch tc ng trc tip ln c cht farnesylpyrophosphat m s prenyl ca Ras

b nh hng do tch ly cc cht trung gian sterol v isopren gy tc dng phn hi

(feedback) ln qu trnh sinh tng hp sterol v cc con ng lin quan do

farnesylpyrophosphat l cht trung gian trong con ng tng hp cholesterol. Tuy nhin

gi thuyt ny sau c chng minh l khng chnh xc khi th nghim cho thy

21

ketoconazol khng c tc dng trn s prenyl ca Ras trong cc t bo. Tuy nhin cc

phn t peptidomimetic ngy cng ng vai tr quan trng trong c ch FTase trong cc

t bo nui cy. 3300 hp cht ca Janssen c sng lc, 36 cht c trin vng

c xc nh, trong 33 cht c ngun gc t imidazol. S hiu bit v vai tr ca

Zn2+

trong hot ng ca FTase cng nh quan im ca Dr. Paul Janssen v c tnh to

phc chelat ca Zn2+ trong cc thuc khng nm imidazol cng c gi thuyt v vai tr

ca Zn2+ v imidazol. Mi quan h cu trc-tc dng (SAR) c my tnh h tr, tm

kim. Hai nhm c la chn l: nhm cc cht c cu trc tng t thuc chng nm

miconazol v nhm c cu trc cng nhc hn t mt quinolinon mu [47]. Hai nhm

c nh gi song song nhng nhm quinolinon nhanh chng cho thy kt qu ha hn.

Trong qu trnh nghin cu, trifluorophenylmethyl-quinolin cho thy kh nng c ch

mnh nhng n nhanh chng b chuyn ha thnh quinolinon tng ng (hnh 2.6). May

mn l hot tnh ca quinolinon c gi li nn thc y cho nghin cu v nhm

quinolinon.

N

NN

N

CF3

N

CF3

N

H

N

N

O

Hnh 2.6: Trifluorophenylmethyl-quinolin b chuyn thnh quinolinon.

Trong n lc tng hp, cht tng t quinolinon 1 c to ra, sau khi th

nghim mt lng ln cc cht c ngun gc t imidazol, 1 cho thy ci tin ni bt v

tim nng ln. y l bc t ph kp thi cho chng trnh nghin cu, cho php tng

hp rng ri cc cht ha hc.

22

Cl

Cl

O

N

NCl

Cl

miconazol

NCl

N

H

O

N

1

A

B

C

Hnh 2.7: Cu trc ha hc ca miconazol v hp cht 1

Hp cht 1 c s dng lm khung tng hp cc hp cht mi, nh gi vai

tr, tm quan trng ca cc nhm th trong phn t. Vng phenyl trong hnh vung A v

B hnh trn nhanh chng c chng minh l cn thit, nu thay th bng hydro hoc

nhm alkyl lm cho cc hp cht ny tr nn mt tc dng. Ngi ta thay th cc nhm

th v tr vng A, B tm ra hp cht c tc dng mnh.

Bng 2.1: Mi quan h gia cu trc- tc dng ca cc nhm th da trn khung l hp cht 1 trong nghin cu SAR ca R-115777

N

N

H

O

N

A

B

A B FT IC50 (M)

1a H 5,35

1b CH3 > 10

1c

> 10

1d Cl

0,18

1e Cl

H

3,4

1f 0,93

1g Cl

Cl

1,9

1h Cl

H3C

5,65

1i Cl

Cl

0,035

23

1j Cl

CH3

0,041

1k Cl

Cl

0,32

1m Cl

CH3

0,20

T bng trn cho thy, vng clorophenyl v tr A v B lm tng kh nng c ch

FTase. C nh A, B l clorophenyl, tip tc thay cc nhm th cc v tr khc tm ra

FTI mnh v hiu qu nht (hnh 2.8)

NCl

Het

O

R1

Cl

Hnh 2.8: C nh 2 nhm clorophenyl v tr A v B, thay mt s nhm th trn khung ca hp cht 1 tm ra hp cht hiu qu nht

Sau qu trnh nghin cu, ngi ta tm ra cc v tr th, nhm th lm tng,

gim tc dng c ch FTase, kt qu l: Het = imidazol-5-yl v R1 = -NH2 l hai nhm

th to ra hp cht c IC50 thp nht, t tm ra hp cht R-115777 l FTI mnh, hiu

qu nht trong s cc cht tng t imidazol (hnh 2.9) [47]. V vy n c tin hnh

th nghim in vitro v in vivo.

Hnh 2.9: Mi quan h cu trc- tc dng trn khung R-115777

24

Ngoi ra, ng phn quang hc cng nh hng n tc dng ca R-115777: (R)

R-115777 tc dng trn cc enzym mnh hn dng (S) 50 ln.

Bng 2.2: Hiu lc tc dng ca cc ng phn quang hc ca R-115777

Hp cht IC50 (enzym)

(nM)

IC50 (t bo)

(nM)

Hn hp

Racemic

ng phn (S)

(R) R-115777

0.8

81

0.6

35

100

1.8

ng ch l R-115777 cng chn lc trn FTase hn hn GGTase-I (hnh 2.10) [47].

Hnh 2.10: S chn lc ca R-115777 vi cc prenyltransferase

2.8.1.3. S tng hp

R-115777 c hng dc phm Janssen Pharmaceutica (Johnson & Johnson)

tng hp. Quy trnh tng hp nh sau:

25

NH

O

Cl

PPA

NH

O

Cl

NH

O

Cl

Cl

OH

O

Cl

O

PPA

NH

O

Cl

Cl

OMeI, NaOH

NO

Cl

Cl

O

CH3

Br2heat

NN CH3

NO

Cl

Cl

CH3

N

N

CH3OH

NH2

NO

Cl

Cl

CH3

N

N

CH3NH2

BuLi

II IV

III

VVIVII

VIII

I

Hnh 2.11: S tng hp R-115777 [85]

2.8.1.4. Tc dng dc l

R-115777 (Tipifarnib, Zarnestra) l mt FTI mnh v chn lc, IC50=0,6

nM

Nghin cu in vitro: khi s dng Tipifarnib 5 M trong 72 gi, t l cc t

bo cht theo chng trnh tng ln ng k khi iu tr kt hp vi DMSO iu tr

cc t bo T. Khi s dng cc t bo T khe mnh, n lm gim t l t bo IFN

(Interferon-gamma), tc dng ny ph thuc vo thi gian. Tipifarnib lm gim t l Ras

hot ha trong lin kt vi DMSO. Tipifarnib s dng c tnh chn lc trong th

nghim in vitro chng li dng t bo to mu MDS (hi chng myelodysplastic) v

tnh nng di 10 nM, tc dng ni bt hn cc t bo trng gc. Tc dng ny

khng phi do cm ng s cht theo chng trnh ca t bo nh bnh thng hay MDS

gc biu th tng ng DiOC3 v s biu hin ca annexin V sau khi tip xc vi

Tipifarnib 72 gi [15]. Tipifarnib gy ra s cht theo chng trnh trong t bo U937.

26

Ngoi ra, hp cht ny c ch c lp FTase ngi cho lamin B v K-Ras 4B vi IC50

tng ng l 0,86 nM v 7,9 nM [96].

Nghin cu in vivo: khi iu tr bng E2 kt hp vi R-115777, Ki-67 trong

cc khi u thp hn so vi khi iu tr bng mt mnh E2. S kt hp ca Tamoxifen v

R-115777 lm lng Ki-67 (5%) thp hn hn khi s dng ring l Tamoxifen (16,9%)

hoc R-115777 (67,3%). Tuy nhin khng thy s khc bit v s cht theo chng trnh

ca t bo gia cc nhm iu tr. S dng mt mnh R-115777 th s lng t bo c

iu tr b c ch thp hn khi kt hp tamoxifen v R-115777 hoc R-115777 v E2.

iu ny c th gii thch cho s gim khi lng ca khi u [96].

Th nghim lm sng: Tipifarnib l FTI u tin c th nghim lm

sng. Th nghim pha I cho thy suy ty v nhim c thn kinh l c tnh liu gii

hn. c tnh trn tiu ha v mt mi cng xut hin [61,82].

Trong cc nghin cu u pha II, Tipifarnib c s dng ng ung liu

300mg2 ln/ngy trong 21 ngy, sau ngh 1 tun. Ba th nghim pha II c bo

co trn cc bnh nhn ung th v tin trin, ung th ty di cn v NSCLC. Th nghim

trn cc bnh nhn ung th v tin trin c 9 p ng 1 phn v 9 trng hp bnh vn

gi nguyn (trong thi gian t nht 24 tun) trong 76 bnh nhn [89]. Trong nghin cu

pha II mi y tng liu Tipifarnib trn c s nguyn tc gim c tnh. Trong 1 nghin

cu, cc bnh nhn b ung th phi t bo nh ti pht s dng liu 400mg2 ln/ngy

trong 14 ngy lin tip, sau ngh 1 tun, khng c i tng no p ng, ch c 1

trng hp bnh khng tin trin [31]. Cho n nay, hot tnh ha hn nht ca

Tipifarnib c ghi nhn trn bnh nhn b bnh bch cu cp tnh khng c iu tr

c nguy c thp hoc hi chng MDS. C 33% p ng (8 p ng hon ton v 2 p

ng mt phn) khi cc bnh nhn dng liu 600mg, 2 ln/ ngy trong 21 ngy. Trong mt

nghin cu pha II khc, 27 bnh nhn c iu tr bng Tipifarnib, c 2 trng hp khi

u gim hon ton v 1 trng hp khi u gim mt phn khi s dng liu 600mg, 2 ln

/ngy trong 4 tun sau ngh 2 tun. Tuy nhin, trong cc bnh nhn b a u ty khng

27

c p ng hon ton hay 1 phn no c ghi nhn, 64% bnh nhn cho thy s n nh

ca bnh vi thi gian trung bnh t lc bt u iu tr n 4 thng [38].

C t nht 2 nghin cu pha III ca Tipifarnib, so snh tc dng ca thuc vi gi

dc v phng php iu tr c bn, cc kt qu cho thy thuc t tc dng vi ung th

i trng tin trin v t l p ng khi iu tr ung th ty bng gemcitabine kt hp vi

Tipifarnib khng cao hn khi iu tr bng mt mnh gemcitabine. Nhng bnh nhn

AML (bch cu cp dng ty) hoc MDS c bt thng nhim sc th 5 v 7 c iu

tr kt hp Tipifarnib vi cytarabine hoc idarubicin s hiu qu hn khi dng mt thuc:

17% p ng khi n tr liu v 58% p ng khi iu tr kt hp 2 thuc.

Hnh 2.12: Tc dng c ch s tng trng t bo ung th tuyn ty ca Tipifarnib do c ch G1, tc dng ph thuc liu s dng.

28

Vai tr: Tipifarnib l mt cht c ch FTase mnh v chn lc, c tc dng

quan trng trong chng ung th.

Dc ng hc:

Nng thuc trong huyt tng cao nht t c sau khi ung 2-4 gi.

Sinh kh dng tuyt i ca Tipifarnib c c on vo khong

34%10% [93].

Chuyn ha, thi tr: Tipifarnib xut hin trong nc tiu ch yu dng

lin hp vi glucuronic, cn trong dch chit phn, nhm methyl-imidazol l con ng

chuyn ha ch yu. Nhn chung, khong 15% Tipifarnib v dng chuyn ha ca n

c thi qua nc tiu, khong 80% c thi qua phn [25].

Qu trnh ADME trong cc ng vt khc nhau l khc nhau v khc vi

trong c th ngi. Cc d liu v dc ng hc nh s nh thanh thi trong huyt

tng, sinh kh dng v con ng chuyn ha trong th nghim trn chut v ch khc

nhau. Do , vic kt hp th nghim in vivo v d liu ADME trong lm sng l rt

quan trng.

2.8.2. Sch-66336

Sch-66336 (Lonafarnib hay Sarasar) l mt FTI khng c cu trc

peptidomimetic, l mt trong hai FTI ng ung trin vng nht hin ang qua th

nghim lm sng pha II trong iu tr cc khi u rn [15,61,82].

2.8.2.1. Cu to ha hc

Khi lng phn t: 638.8

Cng thc phn t: C27H31Br2ClN4O2

N

N

O

N NH2

O

Br

Cl

Br

29

Hnh 2.13: Cng thc cu to ca lonarfanib

Danh php IUPAC: 4-(2-(4-(8-Cloro-3,10-dibromo-6,11-dihydro-5H-

benzo(5,6)cyclohepta(1,2-b)pyridin-11-yl)-1-piperidinyl)-2-oxoethyl)-1-

piperidincarboxamid.

2.8.2.2. Ngun gc, thit kt, qu trnh nghin cu pht trin

Trong qu trnh nghin cu, Schering-Plough tm ra FTI t chng trnh nghin

cu thuc khng histamin. Hot cht c tm ra u tin l Sch-37370, tuy nhin hp

cht ny c kh nng c ch FTase rt yu (IC50= 26,9 M), c hot tnh khng histamin

cao hn (IC50= 0,32 M) [19]. Nghin cu v mi tng quan gia cu trc- tc dng ca

cc hp cht xung quanh Sch-37370 to ra cc hp cht ci thin c ng k tc dng

c ch FTase bng cch ly cc dn xut acetamid ca n do th cc nhm aryl- hoc

heteroaryl- [27]. Vic ti u ha cng thc bao gm c v tr ca acetamid carbonyl [53],

khong cch ca nhm aryl- hoc heteroaryl- vi nhm acetamid carbonyl [4]. Trong cc

hp cht mi tm ra, 2d l cht c IC50 thp nht (IC50 =0,25 M) (hnh 2.14)

Hnh 2.14: Sch-37370 v mt s cht thay i nhm th

Do cc nghin cu SAR sau s dng p-pyridylacetamide (2d) nh l khung

to ra ca FTI mi: th v tr C(3) ca ba vng bng cc nhm thn lipid nh nh clo,

brom hoc methyl to ra cc hp cht vi kh nng c ch FTase khc nhau [55]. Th v

tr C(7) hoc C(10) bng cc nhm halogen cng lm tng tc dng ca cc FTI do bin

i p-pyridylacetamid, to ra cc hp cht mi c mnh tng t nhau [54]. Th 2

30

nhm brom vo C(3) v C(7), hoc C(3) v C(10) to ra hiu qu cao nht cho cc FTI c

cu trc benzocycloheptapyridyl. Ch n C(11), ngi ta nhn thy s bo ha ca

nhm olefin C(11) lm n tng t piperidyl nhng c cc c tnh tt hn, to ra s ti

u ha cho hot tnh ca FTI [54]. ng phn quang hc (S) 3,7-

dibromobenzocycloheptapyridyl v (R) 3,10-dibromobenzocycloheptapyridyl c hiu lc

c ch mnh s farnesyl ca Ras trong th nghim in vitro. Hot lc khc nhau cn ph

thuc vo loi lin kt ca cc cht c ch FTase dibromobenzocycloheptapyridyl v

tng tc khng gian, n lm gim bt hoc tng cng lin kt ca cc dng ng phn

[67]. Mc d hot lc vi FTase tng t nhau nhng 2e v 2f c ch s farnesyl ca Ras

trong t bo COS nhiu hn. Hp cht 2e vi 3,10-dibrom- c tc dng mnh trn s

prenyl ca Ras [54].

N

N

ON

Br

Cl

Br

N

N

ON

Br

Cl

Br

O O

(R) 2e (S) 2f

FTase IC50=1,3 nM FTase IC50=2,6 nM

COS IC50=10 nM COS IC50=480 nM Hnh 2.15: Cu trc ca 2e, 2f

Nghin cu v c tnh dc ng hc ca cc FTI benzocycloheptapyridyl, ngi

ta pht hin ra pyridylacetamid 2e (3,10-dibromobenzocycloheptapyridyl) c kh nng c

ch FTase mnh nhng cc c tnh dc ng hc ca n th khng c chp nhn

[54]. Trong nghin cu v cc c tnh dc ng hc trn chut ca cc FTI 3,10-

dibromobenzocycloheptapyridyl, ngi ta tm ra cc hp cht

piperidylacetamidnicotinamid N-oxid 2g v 2h, piperidylacetamido oxalamid 2i, v

piperidyl-acetamido ure 2j (Sch-66336) n nh hn [73]. Trong cc hp cht ny, Sch-

66336 c la chn l cht c u th hn, c cc thuc tnh dc ng hc ng ung

tt nht (COS IC50= 10 nM; thch mm IC50= 75 nM), AUC (22 M.gi) [54, 73]. Sch-

31

66336 c ch s pht trin ca khi u chut khi s dng nh tc nhn n tr liu v khi

dng kt hp vi thuc khc

2g, R= p-pyridyl-N-oxid (FPT IC50= 2.5 nM; AUC = 16 M.gi)

2h, R= m-pyridyl-N-oxid (FPT IC50= 2.1 nM; AUC = 70 M.gi)

2i, R= C(O)-NH2 (FPT IC50= 2.7 nM; AUC = 45 M.gi)

2j, R= NH2 (FPT IC50= 1.9 nM; AUC = 24 M.gi) [2j= Sch-66336]

Hnh 2.16: Cu trc ca 2g- 2i v Sch-66336

2.8.2.3. S tng hp

Sch-66336 c hng dc phm Schering Corp. (US) - Schering-Plough tng

hp. Quy trnh tng hp nh sau:

32

N

N

Br Cl

O O CH3

H2SO4, NaNO2

N

N

Br Cl

O O CH3

NO2

+N

N

Br Cl

O O CH3

NO2

N

N

Br Cl

O O CH3

NO2

1, Silica gel chromatography2, Fe, CaCl2, EtOH, H2O,

N

N

Br Cl

O O CH3

NO2Br1, NaNO2, HCl, H2O

2, H3PO4, H2ON

N

Br Cl

O O CH3

Br Br2, AcOH

NH

N

Br Cl

NO2Br

1, DIBAL - H

2, chiral separation

NH

N

Br Cl

Br

EDC, HOBt

N

O

OH

Boc

N

N

Br Cl

Br

O

N O

O

CH3

CH3CH3

F3CCOOH,CH2Cl2

N

N

Br Cl

Br

O

NH

Me3Si-N=C=O, CH2Cl2

HCl, H2O,

N

N

Br Cl

Br

O

N NH2

O

IX X

XI

XIIXIIIXIV

XV XVI

XVII

XVIII

XIXXX

Hnh 2.17: S tng hp Sch-66336 [69]

2.8.2.4. Tc dng dc l

Sch-66336 (Sarasar, Lonafarnib) l mt FTI benzocycloheptapyridyl chn lc cho

H-ras, N-ras v K-ras-4B vi IC50 tng ng l 1,9 nM; 5,2 nM v 2,8 nM [95].

Nghin cu in vitro: Sch-66336 nng 0,1 M n 8 M c th c ch s pht

trin ca t bo ung th biu m vy vng u v c, lm t bo cht theo chng trnh,

tc dng ny ph thuc liu lng v thi gian c ch. Sch-66336 (8 M) c ch protein

33

kinase B/ Akt hot ng v phosphoryl ha c cht glycogen synthase kinase Akt - 3 v

yu t phin m. Sch-66336 c ch s pht trin ca nhiu dng t bo, IC50 t 0,6 M

n 32,3 M. Lonafarnib cm ng CCAAT /tng cng lin kt gia cc protein tng

ng, ph thuc vo s hot ha yu t phin m DR5. Lonafarnib (< 10 M) c th hot

ha caspase - 8 v protease cystein cui ca n do gy cht theo chng trnh trong

t bo H1792 (1 dng t bo ung th phi). Lonafarnib (5 M) lm tng phn phi DR5

ti b mt t bo H1792 lm tng qa trnh hoi t khi u, cht theo chng trnh [95].

Nghin cu in vivo: Sch-66336 c ch s pht trin ca khi u phi ngi

trong m hnh cy ghp vo chut t bin suy gim min dch. Trong chut suy gim

min dch NOD/SCID c tim di da EN01, XEN05 hoc XEN08 GBM, Sch-

66336 liu ung 50 mg/kg ng ung trong 21 ngy, c th c ch 69% s tng trng

ca khi u [95].

Th nghim lm sng: Th nghim pha I u tin ca lonafarnib bt u

nm 1997. Sau nhiu nm, cc th nghim khc nhau c thc hin tm ra MTD v

nng cao nht trong huyt tng c th t c [39]. c tnh chnh l tiu chy

nhng bun nn, nn v mt mi cng xut hin. Liu dng ph bin trong nghin cu

pha II l 200mg ng ung, 2 ln/ ngy trn 1 phc lin tc.

Trong mt nghin cu pha II trn cc bnh nhn ung th biu m ng tit niu

tin trin, khng thy phn ng no ca khi u. Mt trong 14 bnh nhn c tnh trng

bnh gi nguyn [65]. Ngoi ra trong 1 th nghim pha II nghin cu v nh hng ca

lonafarnib trn cc bnh nhn ung th i trng di cn, khng ghi nhn c p ng

no. 3 trong 21 bnh nhn c tnh trng bnh gi nguyn trong t nht 4 thng [77]. Yang

v cc cng s tin hnh 1 nghin cu pha II trn cc bnh nhn ha tr, x tr ung th

biu m t bo vy phn u v c, kt qu l: khng ghi nhn c p ng no, nhng

7 trong s 15 bnh nhn duy tr tnh trng bnh n nh trong t nht 3 t iu tr [80].

Sch-66336 hon thnh th nghim lm sng pha II trong iu tr ung th v di

cn [95]. S dng kt hp Sch-66336 (40 mg/m2 din tch c th, bn ln mt ngy) v

Cytoxan (200 mg/m2 din tch c th) hoc Vincristin (1 mg/m2 din tch c th) c tc

34

dng c ch ng k s pht trin ca ung th phi. Lonafarnib tng tc dng ca cc

paclitaxel trong iu tr ung th bung trng (hnh 2.18).

Hnh 2.18: Tc dng ca Lonafarnib v paclitaxel khi s dng ring v khi kt hp trong iu tr ung th bung trng

Trong mt nghin cu khc vi 33 bnh nhn, c iu tr bng taxan nhng

bnh vn tin trin hoc ti pht trong vng 3 thng sau khi iu tr, c iu tr bng

ung lin tc Lonafarnib 100 mg, 2 ln/ngy t ngy u v tim tnh mch paclitaxel

175 mg/m2 t ngy th 8 trong 21 ngy, trong c 29 bnh nhn c nh gi p

ng, 3 bnh nhn (10%) p ng mt phn, 11 bnh nhn (38%) gi nguyn tnh trng

bnh.

Dc ng hc:

Nng thuc cao nht trong huyt tng sau khi ung 6-8 gi [14].

Cc d liu dc ng hc t cc nghin cu trn ngi s dng Lonafarnib cha

c ghi nhn. Tuy nhin, d liu v dc ng hc ca ng vt v ngi rt khc

35

nhau, do cn kt hp th nghim in vivo v nghin cu cc thng s ca qu trnh

dc ng hc c th s dng Sch-66336 trn lm sng c hiu qu.

Tm li, Sch-66336 chng t hot tnh mnh iu tr cc khi u trong cc

th nghim in vitro, in vivo. y l mt FTI khng c cu trc peptidomimetic ng

ung c sinh kh dng cao, l thuc c trin vng trong iu tr nhiu bnh ung th nh

ung th v, ung th bung trng, ung th phi t bo khng nh Hin nay, hp cht

ny ang c nh gi lm sng pha II.

2.8.2.5. Bin i Sch-6633336

to ra cc FTI mnh th hin hot tnh tt trong cc t bo, ngi ta bin i

Sch-66336 bng cch kt hp cc nhm nh amid, acid, este, ure v lactam. Mt s hp

cht ny kt hp cc tnh cht ci thin c im dc ng hc: tng kh nng ha

tan hoc thay i s chuyn ha ca chng. Da vo cu trc ca Sch-66336, ngi ta

tng hp nn cc FTI mi, s dng phng php SAR nh gi hiu qu ca chng

[23,71].

2.8.3. L-778,123

L-778,123 l mt peptidomimetic c ch FTase c kh nng thm qua mng. Vi

kt qu nghin cu tin lm sng y trin vng, L-778,123 ang tip tc tin su vo

cc th nghim lm sng [8].

2.8.3.1. Cu to ha hc

Khi lng phn t: 442.3

Cng thc cu to: C22H21Cl2N5O

CN

CH2

N

N

H2C N

NCl

O . HCl

Hnh 2.19: Cng thc cu to ca L-778123

Danh php IUPAC: : 4-((5-((4-(3-Clorophenyl)-3-oxo-1-piperazinyl) methyl) -1H-

imidazol-1-yl) methyl) benzonitril hydroclorid

36

2.8.3.2. Ngun gc, thit k, qu trnh nghin cu pht trin

Cc cht c ch FTase peptidomimetic l nhm cc cht c ch c nhm thiol.

Nhm thiol ca chng s lin kt vi ion Zn2+ ca FTase bt hot enzym ny. Thay th

thiol bi nhm lin kt vi ion Zn2+ nh imidazol hay cc d vng to ra nhm cc FTI

phi-thiol, phi -peptid, imidazol hoc phi -imidazol. Sau hn 10 nm nghin cu, mt s

FTI c nhm imidazol c th nghim lm sng trong c L-778123 [83].

2.8.3.3. S tng hp

L-778123 c Lobell, R.B (Merck & Co) tng hp. Quy trnh tng hp nh sau

(hnh 2.20)

Qu trnh tng hp L-778123 tri qua 7 bc, hiu sut ton b qu trnh l 24%

[83].

CN

NH2HCl

CN

N

NHS

OH

CN

N

N

OH

CN

N

NHS

Cl

H2N Cl

Cl

HN

HN

OH

O

N

H.HClN

O

Cl

N

N

NN

O

Cl

NC

ab c

g

d,ef

XX XXIXXII

XXIII XXIV Hnh 2.20: S tng hp L-778123: a) DHA, KSCN, CH3CN/H2O, 5500C, 18gi; b) NaNO2, AcOH, H2O, rt, 20 pht; c) Oxalyl clorid, DMF/CH3CN, 0

0C, 3gi; d) Cloroacetyl clorid,

iPrAc, 00C, 1gi; e) Ethanolamin, iPrAc, 550C, 2gi; f) DIAD, Tributylphosphin, EtOAc, -100C,

1gi; g) i-Pr2NEt, CH3CN/H2O, 00C, 39gi

2.8.3.4. Tc dng dc l

37

Dn xut ca CAAX ny c tc dng c ch FTase nng hng nh

khong 10-9 mol. N cng cho hiu lc c ch dng t bo ung th ca K-Ras IC50=

2,3-5,4 nM.

L-778,123 c la chn th nghim lm sng v n l mt FTI mnh,

ng thi cng l mt GGTI, n c kh nng c ch s prenyl ca Rap1A- mt c cht

ca GGTase-I cng nh K-Ras [3]. Trong khi cc FTI khc thng khng c ch hot

ng ca K-Ras v n c th c chuyn thnh GGTase-I.

Nghin cu in vitro: L-778,123 l mt cht c ch c FTase v GGTase-I.

S dng phng php immunoblotting (khng nguyn- khng th) phn bit cc dng

protein b prenyl v khng b prenyl da trn s di chuyn khc nhau ca chng khi in

di [43]. T kt lun c l L-778,123 c tc dng nh mt DPI (cht c ch 2 loi

prenyltransferase) trong cc t bo khi u tuyn ty (PSN-1). L-778,123 c ch s prenyl

ca HDJ2- c cht ca FTase v Rap1A- c cht ca GGTase-I, do l mt DPI nn n c

ch c s prenyl ca K-Ras.

Nghin cu in vivo: cc nghin cu cho thy GGTI gy c cho chut khi

truyn lin tc t 2 ngy tr ln. Mt PDI l tng trn lm sng nhm ch K-Ras

cn c thit k cn bng gia FTI v GGTI sao cho GGTI hot ng mnh c

ch s prenyl cho K-Ras bi GGTase-I nhng cng trnh hot tnh GGTI qu mnh c

th gy ra cc tc dng khng mong mun. nh gi L-778,123 c cn bng gia 2

hot tnh FTI v GGTI, ngi ta o kh nng hp cht ny c ch s prenyl ca K-Ras

khi s dng mt mnh hoc khi kt hp vi thuc c ch chn lc FTase hoc GGTase.

FTI v GGTI c s dng nng ti a c ch cc enzym tng ng ca chng

[43]. IC50 c ch s prenyl K-Ras ca L-778,123 khng b nh hng ng k bi vic

dng FTI hay GGTI, do L-778,123 ti u s cn bng hot tnh c ch FTase v

GGTase trong c ch K-Ras

Th nghim lm sng: trong th nghim pha I ca L-778,123 cc bnh

nhn c truyn lin tc trong 7 ngy, trong nhiu trng hp, bnh nhn c p dng

mi t iu tr 3 tun. HDJ2 (mt protein c farnesyl ha) i din cho cc protein

khc th nghim immunoblot ca cc PBMC (t bo mu n nhn ngoi vi) t cc

38

bnh nhn c iu tr bng truyn L-778,123 trong 7 ngy vi liu 280, 560 v 1120

mg/m2. Trong th nghim ny, s c ch prenyl ca HDJ2 ph thuc liu L-778,123 s

dng. liu 560 mg/m2, trung bnh khong 35% HDJ2 khng b prenyl [9]. Tim truyn

L-778,123 cng c nh gi trong th nghim pha I ko di 2-4 tun. a s cc bnh

nhn trong th nghim ny s dng liu cao nht c th dung np c trong nghin cu

truyn 7 ngy: 560 mg/m2 L-778,123. Vi liu 840 mg/m2, tun th 2, c ti 75%

HDJ2 khng b prenyl.

Hnh 2.21: S c ch FTase trong cc bnh nhn c iu tr bng L-778,123

A: th nghim immunoblot HDJ2 ca PBMC trong 3 bnh nhn c iu tr bng liu 280, 560, hoc 1120 mg/kg/ngy trong 7 ngy

B: phn tch HDJ2-PBMC trong 2-4 tun truyn L-778,123. T l HDJ2 khng c prenyl trong 4 nhm bnh nhn

Cc nghin cu cho thy L-778,123 c ch FTase v mt phn GGTase ngi,

tuy nhin cc hp cht thiu hiu lc c ch s prenyl ca K-Ras. Do cc th

nghim lm sng ca L-778,123 cha kim tra gi thuyt c ch s prenyl ca K-

Ras bi DPI c th gy phn ng ng k ca khi u, c th gy cht chut khi dng

liu c ch K-Ras. Khi truyn lin tc GGTI trong 48-72 gi liu c th c ch s

prenyl ca K-Ras khi kt hp vi FTI cng gy t vong cho chut, do khng nn

nghin cu lm sng cc DPI mnh hn L-778,123.

39

Trong th nghim khc, L-778,123 c tim truyn tnh mch lin tc trong 7,

14 hoc 21 ngy, c tnh liu gii hn l gim tiu cu hoc gim bch cu a nhn

trung tnh. Khng ghi nhn c mc tiu p ng no mc d t c nng n

nh trong huyt tng. Trong cc th nghim, thy c s ko di QT trong 1 hoc

nhiu bnh nhn mc d khng phi liu gii hn v khng lp li khi dng liu thp hn.

V th ngi ta quyt nh dng pht trin hp cht ny [9].

Dc ng hc

Cha c d liu nghin cu qu trnh dc ng hc ca L-778,123

2.8.4. BMS-214662

BMS-214662 c cu trc lng c cht l mt FTI ng ung mnh v chn lc

thuc nhm cc FTI phi peptidomimetic, ang c tin hnh th nghim pha I [52].

2.8.4.1. Cu to ha hc

Khi lng phn t: 489.6

Cng thc ha hc: C25H23N5O2S2

Hnh 2.22: Cng thc cu to ca BMS-214662

Danh php IUPAC: (R)-7-Cyano-2,3,4,5-tetrahydro-1-(1H-imidazol-4-ylmethyl)-

3-(phenylmethyl)-4-(2-thienylsulfonyl)-1H-1,4-benzodiazepin.

2.8.4.2. Ngun gc, thit k, qu trnh nghin cu pht trin

Giai on u ca qu trnh nghin cu, cc FTI ch yu c thit k c cu trc

peptidomimetic: cha nhm thiol, tuy nhin cc hp cht ny khng c tc dng nh

mong i. Sau , nhm cht c ch FTase c cu trc phi-thiol, phi -peptid c pht

hin [73]. Trong n lc tm kim nhm cht c kh nng c ch mnh, nhm cc cht c

40

nhm imidazol-4-ylalkyl gn vo 2,3,4,5-tetrahydro-1, 4-benzodiazepin c tm ra

[18]. S dng phng php SAR tm ra hp cht c hiu lc mnh nht trong nhm

ny, cc nghin cu xc nh cc cht c hot lc trn cc khi u c t bin K-Ras

trong m hnh chut mang t bo ung th. Kt qu ca cc nghin cu trn dn n hp

cht 4 (BMS-214662) c a vo th nghim lm sng.

Sau khi pht hin nhm cc cht c ch FTase mnh da trn khung 2,3,4,5-

tetrahydro-1,4-benzodiazepin c nhm imidazol gn vo v tr N-1 [18]. Cc nghin cu

SAR tp trung vo cc dn xut imidazol-4-ylmethyl trong cc nhm th c thay

i, tp trung vo vng aryl cng nh trn N-4. Cc nghin cu ny chng minh l

mt nhm th k nc lin kt vi N-4 thng qua mt nhm c lin kt hydro, cc nhm

th k nc v tr 7,8 cng quan trng vi kh nng c ch enzym (hnh 2.23).

Hnh 2.23: M hnh tng tc ca cc imidazolylmethyltetrahydrobenzodiazepine vi FTase

v tr N-4 c th to lin kt hydro vi enzym, ngi ta th vo v tr N-4 l

CO hoc SO2. Vic tng hp cc imidazolylmethyltetrahydrobenzodiazepin da vo vic

to ra cc vng quanh tetrahydrobenzodiazepin, sau bin i, hp nht cc vng v

tr N-1 v N-4, cng dng cch ny thm d hiu lc ca cc nhm th v tr C-2, C-

3. SAR ca cc hp cht ny ban u c nghin cu trong cc cht tng t c nhm

N-1 imidazol-4-ylmethyl v nhm N-4 naphthoyl

Nghin cu SAR ca 4 nhm th chng minh hiu lc ca cc FTI vi

carboxamid, ure, carbamat, sulfonamid, sulfonylure to ra cc cht c ch tng i

41

mnh. Tuy nhin, sulfonamid thng vt tri so vi carboxamid c v tim nng c ch

FTase cng nh cc hot ng t bo, trong hp cht 4.19 l FTI c IC50 thp nht

(bng 2.3).

Tt c cc FTI nhm ny c th nghim v chn lc FTase v GGTase-I,

cho thy chn lc vi FTase cao hn, 4.19 c ch FTase mnh hn GGTase 1000 ln.

Bng 2.3: S tng tc ca cc nhm th C-3 v N-4 trong nghin cu SAR ca BMS-214662

Hp cht R3 ng phn R3 X R4 R7 FT IC50 (nM)

4.1 H CO naphth-1-yl H 456 128

4.2 H CO naphth-1-yl Br 228 7

4.3 Me R,S CO naphth-1-yl H 1100 280

4.4 CH2-phenyl R,S CO naphth-1-yl H 276 102

4.5 CH2-phenyl R,S CO Me H 1300 460

4.6 CH2-phenyl R,S CO Me Br 60 24

4.7 CH2-phenyl R CO Me CN 8,75 2,25

4.8 CH2-phenyl R CO NMe2 CN 17 4

4.9 CH2-phenyl R CO OEt CN 22 3

4.10 Naphth-1-yl R,S CO Me Br 54,5 14,5

4.11 Naphth-2-yl R,S CO Me Br 1260 146

4.12 CH2-phenyl R,S SO2 Me Br 30 12

4.13 CH2-phenyl R SO2 Me Br 10,7 0,4

4.14 CH2-phenyl S SO2 Me Br 437 82

4.15 CH2-phenyl R SO2 2-thienyl CN 1,35 0,05

4.16 CH2-phenyl R SO2 CH2CH2NMe2 CN 1,53 0,97

4.17 CH2-phenyl R SO2 Phenyl CN 1,77 0,09

4.18 CH2-phenyl R SO2 CH2CH2CH3 CN 1,77 0,57

4.19 CH2-phenyl R SO2 NMe2 CN 2,85 0,05

4.20 CH2-phenyl R SO2 Me CN 3,0 1,1

42

4.21 CH2-phenyl R,S SO2 Me Pyrid-3-yl 7,9 0,1

4.22 CH2-phenyl R SO2 Me Pyrid-4-yl 16 4

4.23 CH2-phenyl R,S SO2 Me phenyl 54,5 15,5

4.24 2-Cl- phenyl R,S SO2 Me Br 18 7

4.25 3-Cl- phenyl R,S SO2 Me Br 24 13

4.26 NHCO- phenyl R,S SO2 Me Br 86 39

4.27 4-MeO- phenyl R,S SO2 Me Br 101 29

4.28 Pyrid-3-yl R SO2 Me phenyl 5,95 1,85

4.29 Pyrid-4-yl R SO2 Me phenyl 383 150

4.30 c-Hex R SO2 Me Br 23,5 5,5

2.8.4.3. S tng hp

BMS-214662 c Hunt, J. T v cng s tng hp. S tng hp nh hnh 2.24

[91].

HN O

Br

O

O

+

NH2O

H3C

O

.HCl

DMAP, pyridine, reflux

NH

NH

O

O

Br

NH

NHBr

BH3, THF, reflux

NH

NHNC

CuCN, NMP

SClO2S

i-Pr2NEt, CH2Cl2NH

NNC

O2S

S

N

HN

H

O

N

NNC

O2S

S

HN

N

NaBH(OAc)3, AcOH, Cl(CH2)2Clor Et3SiH, CF3COOH, CH2Cl2

XXV

XXVI XXVII

XXVIIIXXIX

XXX

XXXI

XXXII

Hnh 2.24: S tng hp BMS-214662

2.8.4.4. Tc dng dc l

BMS-214662 c tc dng tt trong c ch H-Ras t bin nhng khng c

tc dng vi K-Ras v cc oncogen khc. Cc nghin cu cho thy BMS-214662 c tc

43

dng tt vi ung th biu m bung trng A2780, ung th biu m t bo rut kt HCT-

116 v l FTI c kh nng gy cht theo chng trnh mnh nht [84].

Hnh 2.25: Tc dng trn khi u khi s dng BMS-214662 ng ung trn cc mc khi u HCT-116 trong m hnh chut b t bin suy gim min dch mang t bo ung th ngi. Cc cht c s dng t th hai n th su, : kim sot(khng c ch); : 300 mg/kg; : 400 mg/kg; : 600 mg/kg

Nghin cu in vitro: FTI BMS-214662 c kh nng gy cht theo chng

trnh trong cc t bo bch cu myeloid mn tnh CD34+ do tng cng cc tn hiu cht

theo chng trnh.

Th nghim lm sng: BMS-214662 gy c trn tiu ha nn cc nghin

cu tp trung vo a thuc bng ng tim truyn tnh mch [11].

BMS-214662 c th nghim vi cc bnh nhn bch cu cp tnh ti pht hoc

c nguy c cao b hi chng MDS. Lc u BMS-214662 c s dng nh liu tn

cng 1 gi/tun liu 42 n 157 mg/m2. Sau khi xc nh c MTD, phc c

thay i thnh truyn lin tc 24 gi mi tun, bt u vi liu 300 mg/m2. Trong 30

bnh nhn ca th nghim, 1 bnh nhn c iu tr vi liu 42 mg/m2, 3 bnh nhn

c iu tr vi liu 56 mg/m2, 3 bnh nhn c iu tr vi liu 84 mg/m2, 13 bnh

nhn c iu tr vi liu 118 mg/m2, 6 bnh nhn c iu tr vi liu 157 mg/m2 v 4

bnh nhn c iu tr vi liu 300 mg/m2. c tnh liu gii hn (DLT) xy ra vi 3

bnh nhn c iu tr vi liu 157 mg/m2, bao gm bun nn, nn, h kali mu, tiu

44

chy v cc vn tim mch, khng c c tnh vi trng hp truyn lin tc 24 gi.

MTD khi truyn trong 1 gi l 118 mg/m2, khng xc nh c MTD vi truyn lin tc

24 gi. Nng thuc trong huyt tng ph thuc liu s dng. BMS-214662 c ch

hot ng ca khong 60% FTase sau khi truyn lin tc v phc hi sau 24 gi, n c

dung np tt khi truyn trong 1 gi liu 118 mg/m2 [89].

30 bnh nhn c iu tr (19 ngi b bnh bch cu myeloid cp, 3 ngi b

bnh bch cu lymphoblastic cp v 8 ngi c nguy c cao b hi chng

myelodysplastic) c tui th trung bnh l 53 (t 22 n 96). 15 bnh nhn p ng mt

phn, 14 bnh nhn p ng hon ton (thi gian p ng trung bnh l 22 tun). Mt

bnh nhn b bnh bch cu myeloid cp, 96 tui khng iu tr bng ho tr liu.

Hnh 2.26: Kh nng c ch FTase cc t bo mu n nhn ngoi vi ca BMS-214662

Dc ng hc:

Bng 2.4: Kt qu d liu dc ng hc ca BMS-214662 trn cc bnh nhn

Liu BMS-214662

(mg/m2)

S bnh

nhn

Cmax

(mg/mL)

AUCinf

(mg/mL h)

Cl

(mL/min/m2)

VSS

(L/m2)

t1/2

(gi)

42 1 857 1,354 519 39,3 1,1

56 2

45

Liu BMS-214662

(mg/m2)

S bnh

nhn

Cmax

(mg/mL)

AUCinf

(mg/mL h)

Cl

(mL/min/m2)

VSS

(L/m2)

t1/2

(gi)

Trung bnh 748 1,090 423 86,0 2,3

S liu

thc t 462 v 1,035 604 v 1,575 255 v 592

52 v

120

2,6 v

2,0

84

2

Trung bnh 2,363 2,577 542 27,1 1,5

S liu

thc t

2,744 v

1,981

2,536 v

2,618 552 v 534

24,6 v

29,6

1,7 v

1,3

118

6

Trung bnh 3,202 4,997 353 33,2 3,1

SD 646 2,181 96 18,6 1,1

157

2

Trung bnh 5,634 13,732 292 38 3,1

S liu

thc t

7,244 v

4,024

21,835 v

5,629 120 v 464

26 v

49,2

3,8 v

2,3

Cmax trung bnh l 2,681 mg/mL ( lch chun [SD] 3745) t c vo cui

khi truyn dch.AUC (0 n 24 gi) l 25,620 mg/mLgi (SD 25,881). Khi s dng

liu thp, Cl ca BMS-214662 cao hn Cl khi s dng liu cao, Vss ca thuc tng

i nh.

46

Hnh 2.27: Nng BMS-214662 trong huyt tng khi tim tnh mch

Nh vy, BMS-214662 l mt FTI mnh trong cc th nghim, mt thuc iu

tr ung th tim nng, nht l iu tr cc bnh cc bnh bch cu.

2.8.5. Cc FTI c ngun gc t nhin

Acid Chaetomellic A v B l 2 ng phn, c phn lp v tch chit t qu trnh

ln men ca Coelomycete Chaetomella acutiseta. Acid Zaragozic A c K.E.Wilson

(phng ngin cu Merck) cung cp, cc cht tng t acid Zaragozic A c R. W.

Marquis v G. D. Berger (phng nghin cu Merck) tng hp. Acid (-hydroxyfarnesyl)

phosphonic c cung cp bi N. J. Anthony v R. P. Gomez (phng nghin cu

Merck).

xc nh cc FTI mi, cc nghin cu nh gi cc sn phm t qu trnh

ln men ca Coelomycete C. acutiseta. Hai hp cht mi c phn lp v t tn l

acid Chaetomellic A v B. Cu trc ca 2 hp cht ny c th hin trong hnh 2.28

[58]. Cc FTI khc c phn lp t qu trnh ln men ca vi sinh vt khc l acid

zaragozic A. Hp cht ny trc y c dng c ch squalensynthase (Ki=78 pM),

mt enzym cng s dng farnesyldiphosphat.

47

Hnh 2.28: Mt s FTI

Cc hp cht ny u c ch FPTase, GGPTase-I v GGPTase-II, nhng mc

chn lc khc nhau (bng 2.5)

Bng 2.5: S chn lc ca cc FTI c ngun gc t nhin vi FTase v GGTase Hp cht

IC50 (nM)

FTase GGTase-I GGTase-II

Acid chaetomellic A 55 92,000 34,000

Acid chaetomellic B 185 54,000 ND

Acid zaragozic A 216 620 66,000

Cht tng t acid zaragozic A 12 1,710 16,800

Acid -hydroxyfarnesyl) phosphonic 30 35,800 67,000

Cc acid chaetomellic v (-hydroxyfarnesyl) phosphonic chn lc vi FTase hn

hn GGTase. Acid zaragozic A cng chn lc vi FTase hn nhng mc chn lc

khng cao hn GGTase-I nhiu. Tuy nhin, iu th v l khi bn tng hp cht tng t

acid zaragozic A bng cch bin i mt lin kt ca acid zaragozic A th hp cht mi

chn lc vi FTase hn hn hp cht ban u. Kt qu ny cho thy mt tim nng ha

hn c th to ra cc hp cht c ch FTase mnh v chn lc bng cch thay i cu trc

ca cc hp cht t nhin.

48

C ch c ch FTase ca acid (-hydroxyfarnesyl) phosphonic l cnh tranh vi

c cht farnesyl diphosphat. xc nh cc sn phm t nhin c ch FTase bng cch

cnh tranh vi c cht farnesyl diphosphat hay CAAX hay c hai, ngi ta lm mt

nghin cu su hn: s dng cc hp cht mnh mi nhm nghin cu. Acid

chaetomellic A v cht tng t acid zaragozic A c th nghim, kt qu nh sau.

Bng 2.6: Gi tr Ki ca mt s FTI c ngun gc t nhin

Cht c ch

Cnh tranh vi FDP Cnh tranh vi Ras

Loi c ch Ki Loi c ch Ki

nM nM

Acid Chaetomellic A Cnh tranh 3.50.2 Cnh tranh 2.80.2

Cht tng t zaragozicA Cnh tranh 1.00.3 Cnh tranh 0.70.07

Acid -hydroxyfarnesyl)

phosphonic

Cnh tranh 5.20.7 Cnh tranh 4.70.5

Hnh 2.29: S c ch FTase ca acid chaetomellic A v cht tng t acid zaragozicA

49

Cc d liu trn cho thy: acid chaetomellic A v cht tng t acid zaragozic A

c cu trc, ngun gc khc nhau nhng c cng c ch l cnh tranh vi

farnesyldiphosphat

Tc dng c ch FTase ca cc hp cht trong t bo: acid (-hydroxyfarnesyl)

phosphonic c th c ch qu trnh Ras nng > 1 M, nng 0,1M hoc thp

hn th hp cht ny khng th hin tc dng. Tuy nhin, acid chaetomellic A v cht

tng t acid zaragozic A khng c ch qu trnh Ras khi th nghim nng ln

ti 100 M trong 24 gi.

50

KT LUN

Sau mt thi gian tra cu, c, phn tch v tng hp cc ti liu tham kho,

chng ti thu c cc kt qu sau:

1. trnh by c nhng c im sinh hc c bn ca farnesyltransferase v vai

tr ca n trong c ch bnh sinh ca ung th.

Farnesyl transferase l mt enzym xc tc cho phn ng farnesyl ha bng cch

nhn dng mu CAAX u tn cng C ca Ras v chuyn nhm 15-carbon farnesyl t

farnesyl diphosphat ti kt hp vi cystein ca Ras. Gen Ras thng b t bin trong cc

khi u hn cc gen khc. Ras c tng hp protein dng cha hot ng, chuyn

thnh dng hot ng n phi tri qua mt chui bin i, trong phn ng farnesyl ha

l phn ng u tin v quan trng nht. Theo , FTase b c ch s ngn s bin i

thnh dng hon thin, c kh nng hot ng ca Ras. FTase c xem nh mc tiu

iu tr tim nng cho cc bnh ung th do t bin Ras.

2. trnh by c mt s cht c ch FTase trin vng ang c pht trin gn

y

Da vo nghin cu v cu trc, hot ng ca FTase, 4 nhm FTI c tm ra

v pht trin:

Cc FTI c cu trc tng t vi FDP: cnh tranh vi c cht FDP gim phn ng

farnesyl ha ca Ras, bng cch gn vi FTase v tr gn ca FDP.

Cc FTI c cu trc tng t CAAX: cnh tranh vi CAAX ca Ras lin kt vi

FTase.

Cc FTI lng c cht: kt hp cc c im ca 2 nhm trn. Cc FTI loi ny chn

lc vi FTase nhiu hn so vi GGTase v c tc ng ti thiu ln t bo bnh

thng. Cc hp cht ny cng c ch tn hiu Ras v s pht trin ca cc t bo H-

Ras v K-Ras t bin nng thp.

51

Cc FTI khc c ngun gc t nhin cha r c ch tc dng. Sng lc ngu nhin

cc sn phm t nhin v t vi sinh vt bng cch s dng gen ca nm men cc

cht c ch Ras thm vo trong t bo, dn n xc nh mt s FTI.

Qu trnh nghin cu tm ra mt s FTI c hiu lc c ch FTase mnh, c tnh

chn lc cao, ang c th nghim lm sng vi cc kt qu trin vng nh R115777,

SCH66336, L-778,123, BMS-214662 v nhiu FTI c ngun gc t nhin v tng hp

ha hc ang c nghin cu cng cho cc kt qu ha hn. Nhng kt qu trn y

chng t hng nghin cu cc thuc iu tr ung th mi da trn cc cht c ch

farnesyltransferase ni ring v mc tiu phn t ni chung l ng n v y trin vng

trong tng lai.

DANH MC TI LIU THAM KHO

TI LIU TING VIT

1. Bi Thu Quyn (2009), Cc mc tiu phn t hin nay trong nghin cu pht trin

cc thuc iu tr ung th. Kha lun tt nghip dc s i hc. Trng i hc Dc

H Ni, H Ni.

TI LIU TING ANH

2. Basu TN, Gutmann DH, Fletcher JA, et al (1992), Aberrant regulation of ras

proteins in malignant tumour cells from type I neurofibromatosis patients. Nature356,

713-715.

3. Bergman, JM, Abrams, MT, Davide, JP, et al (2001), Aryloxy substituted N-

arylpiperazinones as dual inhibitors of farnesyltransferase and geranylgeranyltransferase-

I, Bioorg. Med. Chem. Lett 11, (11), 1411 1415.

4. Bishop WR, Bond R, Petrin J, et al (1995), Novel Tricyclic Inhibitors of Farnesyl

Protein Transferase, J. Biol. Chem, 270, 30611-30618.

5. Boguski MS and McCormick F, (1993), Nature366, 643-654.

6. Bos JL (1989). rasoncogenes in human cancer: a review, Cancer Res, 49:

46824689.

7. Boyle P, Levin B (2008), World Health Organization - International Agency for

Research on Cancer, Lyon, World Cancer Report 2008.

8. Britten C, Rowinsky E, Yao S-L, Soignet N, et al (1999). The farnesyl protein

transferase (FPTase) inhibitor L-778,123 in patients with solid cancer. Proc. Am. Soc.

Clin. Oncol. Annu. Meet, 18, 155a

9. Britten CD, Rowinsky EK, Soignet S,et al, A Phase I and pharmacologic study of

the farnesyl protein transferase inhibitor L-778,123 in patients with solid

malignancies, Clin Cancer Res, 7, 3894 3903

10. Brown MS, Goldstein JL, Paris KJ, et al (1992), Tetrapeptide inhibitors of

protein farnesyltransferase: Amino-terminal substitution in phenylalanine- containing

tetrapeptides restores farnesylation, Proc Natl Acad Sci USA, 89, 8313-8316

11. Camacho LH, Soignet S, Pezzuli S, et al (2001) Dose escalation study of oral

farnesyl transferase inhibitor (FTI) BMS-214662 in patients with solid tumors, Proc Am

Soc Clin Oncol, 20, 311

12. Casey PJ, (1989) p21ras is modified by a farnesyl isoprenoid, Proc. Natl. Acd.

Sci. USA, 86 (21), 8323-8327

13. Chen WJ, Andres DA, Goldstein JL, et al, (1991), cDNA cloning and expression

of the peptide-binding _ subunit of rat p21ras farnesyltransferase, the counterpart of yeast

DPR1/RAM1, Cell, 66, 327334,

14. Crul M, de Klerk GJ, Swart M, et al (2002), Evaluation of the bioequivalence of

tablets and capsules containing the novel anticancer agent R115777 (Zarnestra) in

patients with advanced solid tumors, Eur J Drug Metab Pharmacokinet; 27, 6165.

15. Crul M, de Klerk GJ, Swart M, et al (2002), Phase I clinical and pharmacologic

study of chronic oral administration of the farnesyl protein transferase inhibitor R115777

in advanced cancer, J Clin Oncol, 20, 27262735.

16. De Coster R, Caers I, Coene MC,et al (1986), Effects of high dose ketoconazole

therapy on the main plasma testicular and adrenal steroids in previously untreated cancer

patients, Clin Endocrinol, 24, 657-664.

17. DeSolms SJ, Deana AA, Giulian EA, et al (1995), Pseudodipeptide inhibitors of

protein farnesyltransferase, J Med Chem, 38, 3967-3971

18. Ding CZ; Batorsky R, Bhide R, et al (1999), Discovery and Structure-Activity

Relationships of Imidazole-Containing Tetrahydrobenzodiazepine Inhibitors of

Farnesyltransferase, J. Med. Chem, 42, 5241-5253.

19. Doll RJ (2001), Inhibition of farnesyl protein transferase- A review of the recent

patent literature, IDrugs, 4, 1382-1388.

20. Dunten, Pete (1998), "Protein Farnesyltransferase: Structure and Implications for

Substrate Binding", Biochemistry, 37 (22), 7907-7912.

21. End DW, Smets G, Todd AV et al (2001). Characterization of the antitumor

effects of the selective farnesyl protein transferase inhibitor R115777 in vivo and in

vitro. Cancer Res, 61, 131137.

22. Eric KR, Jolene JW and Daniel DV (1999), Ras Protein Farnesyltransferase: A

Strategic Target for Anticancer Therapeutic Development, American Society of Clinical

Oncology, 17, 3631-3652.

23. George FN, Bancha V, Patrick P, et al (2003), Ganguly

Trihalobenzocycloheptapyridine Analogues of Sch 66336 as Potent Inhibitors of Farnesyl

Protein Transferase, Bioorganic & Medicinal Chemistry, 11,139143.

24. Garcia AM, Rowell C, Ackermann K, et al (1993), Peptidomimetic inhibitors of

Ras farnesylation and function in whole cells, Biol Chem, 268, 18415-18418

25. Garner RC, Goris I, Laenen AA et al (2002). Evaluation of accelerator mass

spectrometry in a human mass balance and pharmacokinetic studyexperience with 14C-

labeled (R)-6-[amino(4- chlorophenyl)(1-methyl-1H-imidazol-5-yl)methyl]-4-(3

chlorophenyl)-1- methyl-2(1H)-quinolinone (R115777), a farnesyl transferase inhibitor,

Drug Metab Dispos, 30, 823830.

26. Gibbs JB (1993) Lipid modifications of proteins in the Ras superfamily, in

Birnbaumer L, Dickey B (eds): GTPases in Biology. New York, NY, Springer-Verlag,

335-344.

27. Gibbs JB, Anthon, NJ, Buser CA, et al (2000), Farnesyltransferase inhibitors as

potential anticancer agents, Abstracts 219th Am. Chem. Soc. Natl. Meeting, Med. Chem,

292.

28. Gill M, (1982) Phytochemistry, 21, 1786-1788.

29. Hancock JF, Paterson H, Marshall CJ (1990). A polybasic domain or

palmitoylation is required in addition to the CAAX motif to localize p21ras to the plasma

membrane, Cell, 63, 133139.

30. Hancock JF, Cadwallader K, and Marshall CJ (1991) Methylation and proteolysis

are essential for efficient membrane binding of prenylated p21K-ras(B). EMBO J, 10:

641646.

31. Heymach JV, Johnson DH, Khuri FR et al (2004). Phase II study of the farnesyl

transferase inhibitor R115777 in patients with sensitive relapse small-cell lung cancer,

Ann Oncol, 15, 11871193.

32. Jackson JH, Li JW, Buss JE, et al (1994): Polylysine domain of K-ras 4B protein

is crucial for malignant transformation, Proc Natl Acad Sci U SA, 91, 12730-12734.

33. James G, Goldstein JL, Brown MS (1996), Resistance of K-RasBV12 proteins to

farnesyltransferase inhibitors in Rat1 cells, Proc Natl Acad Sci U SA, 93, 4454-4458.

34. James GL, Goldstein JL, Brown MS (1995), Polylysine and CVIM sequences of

K-RasB dictate specificity of prenylation and confer resistance to benzodiazepine

peptidomimetics in vitro, J Biol Chem, 266, 14603-14610.

35. Johnston SR, Hickish T, Ellis P et al (2003), Phase II study of the efficacy and

tolerability of two dosing regimens of the farnesyl transferase inhibitor,R115777, in

advanced breast cancer, J Clin Oncol, 21, 24922499.

36. Khosravi-Far R, Der CJ (1994), The Ras signal transduction pathway, Cancer

Metastasis Rev, 13: 67-89.

37. Krengel U, Schlichting L, Scherer A et al (1990), Three-dimensional structures of

H-ras p21 mutants: molecular basis for their inability to function as signal switch

molecules, Cell, 62, 539548.

38. Lancet JE, Karp JE, Gotlib L et al (2002), Zarnestra (R115777) in previously

untreated poor-risk AML and MDS: preliminary results of a phase II trial, Blood, 100,

560a.

39. Lantry LE, Zhang Z, Yao R et al (2000), Effect of farnesyltransferase inhibitor

FTI-276 on established lung adenomas from A/J mice induced by 4-(methylnitrosamino)-

1-(3-pyridyl)-1-butanone, Carcinogenesis, 21: 113116

40. Lebowitz PF, Casey PJ, Prendergast GC, Thissen JA (1997), Farnesyltransferase

inhibitors alter the prenylation and growth-stimulating function of RhoB, J. Biol.

Chem, 272, 15591-15594.

41. Lebowitz PF, Sakamuro D, Prendergast GC (1997), Farnesyl transferase

inhibitors induce apoptosis of Ras-transformed cells denied substratum attachment,

Cancer Res, 57, 708-713.

42. Leonard DM (1997), Ras farnesyltransferase: a new therapeutic target, J. Med.

Chem, 40: 2971-2990.

43. Lobell RB, Omer CA, Abrams MT, et al (2001), Evaluation of farnesyl:protein

transferase and geranylgeranyl:protein transferase inhibitor combinations in preclinical

models, Cancer Res, 61, 8758 8768.

44. Long SB, Hancock PJ, Kral AM et al (2001), The crystal structure of human

protein farnesyltransferase reveals the basis for inhibition by CaaX tetrapeptides and their

mimetics, Proc Natl Acad Sci U S A, 98, 1294812953.

45. Long Stephen B, et al (1998), "Cocrystal Structure of Protein Farnesyltransferase

Complexed with a Farnesyl Diphosphate Substrate", Biochemistry, 37, (27), 9612-9617.

46. Lowy DR and Willumsen BM, (1993), Arylheteroaryl inhibitors of farnesyl-

protein transferase Ann. Rev.Biochem., 62, 951-891.

47. Marc Venet, David End and Patrick Angibaud (2003), Farnesyl Protein

Transferase Inhibitor ZARNESTRATM R115777 History of