A comparison of two orally bioavailable anti-cancer agents, IRC-110160 and STX140.
This study characterises two recently developed anticancer agents in vitro and in vivo, 2-methoxyoestra-1,3,5(10), 16-tetraene-3-carboxamide (IRC-110160) and STX140.


METHODS
Hormone-dependent (MCF-7), hormone-independent (MDA-MB-231) and P-glycoprotein overexpressing (MCF-7Dox) cells were used for proliferation experiments. For the tumour efficacy studies, female nude mice were inoculated with MDA-MB-231 cells.


RESULTS
IRC-110160 is a potent inhibitor of both MCF-7 and MDA-MB-231 cell proliferation. Furthermore, the potency of IRC-110160 was unaffected by the over-expression of the P-glycoprotein drug efflux pump. IRC-110160 and 2-methoxyoestradiol-3,17-O,O-bis-sulfamate (STX140) induced apoptosis in a similar timeframe in the MDA-MB-231 cell line, but only STX140 caused G2/M arrest in these cells. In the MDA-MB-231 xenograft model 300 mg/kg p.o. (daily) of IRC-110160 and 20 mg/kg p.o. STX140 (daily) both completely inhibited tumour growth; however some toxicity was observed with IRC-110160. After 28 days of daily dosing STX140 (20 mg/kg p.o.) had minimal effect on the white blood population of mice with tumours. The masking of STX140 from white blood cells may be due to its interaction with carbonic anhydrase II (CAII) in the red blood cells. In contrast to STX140, IRC-110160 does not inhibit CAII. These studies highlight the activity of two orally bioavailable anti-cancer agents one of which, STX140, may offer a significant clinical advantage over existing drugs as a common dose limiting factor, haemotoxicity, may be minimised.
Foster
Paul A
PA
Endocrinology and Metabolic Medicine and Sterix Ltd., Faculty of Medicine, Imperial College London, St. Mary's Hospital, London W2 1NY, UK.
Stengel
C
C
Ali
Tauhid
T
Leese
Mathew P
MP
Potter
Barry V L
BV
Reed
Michael J
MJ
Purohit
Atul
A
Newman
Simon P
SP
D000284:Administration, Oral; D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D048708:Cell Growth Processes / Q000187:drug effects; D045744:Cell Line, Tumor; D018920:Coculture Techniques; D004354:Drug Screening Assays, Antitumor; D042783:Endothelial Cells / Q000166:cytology / Q000187:drug effects; D004963:Estrenes / Q000494:pharmacology* / Q000633:toxicity; D005260:Female; D005347:Fibroblasts / Q000166:cytology; D006801:Humans; D051379:Mice; D009376:Neoplasms, Hormone-Dependent / Q000188:drug therapy* / Q000473:pathology; D009389:Neovascularization, Pathologic / Q000188:drug therapy; D014404:Tubulin / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays
C526438:2-methoxyestradiol-3,17-O,O-bis(sulfamate); C530263:2-methoxyoestra-1,3,5(10),16-tetraene-3-carboxamide; D000970:Antineoplastic Agents; D004963:Estrenes; D014404:Tubulin