title: Inhibition of heat shock protein (Hsp) 90 potentiates the antiproliferative and pro-apoptotic effects of 2-(4'fluoro-phenylamino)-4H-1,3-thiazine[6,5-b]indole in A2780cis cells.
abstract: Ovarian carcinoma is initially sensitive to platinum-based therapy, but become resistant over time. The study of cancer sensitizing substance is therefore the major challenge for a number of scientific groups. Our experiments were carried out on human ovarian adenocarcinoma A2780cis cells resistant to cisplatin and their response to 2-(4'fluoro-phenylamino)-4H-1,3-thiazine[6,5-b]indole (thiazine[6,5-b]indole) and/or heat shock protein (Hsp) 90 inhibitor 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) using proliferation assay, cell cycle analysis and monitoring of apoptosis were examined. A2780cis cells revealed the same fold of resistance to Hsp90 inhibitor 17-DMAG as it is declared for cisplatin (18 times), but only 3.2 times for thiazine[6,5-b]indole. Our results showed that the combination of thiazine[6,5-b]indole and 17-DMAG significantly reduced proliferation of A2780cis cells and led to their accumulation in G2/M phase of the cell cycle. Moreover, both thiazine[6,5-b]indole as well as 17-DMAG increased the number of annexin V positive A2780cis cells in time dependent manner. Interestingly, thiazine[6,5-b]indole treatment significantly activated also caspase-3 compared to untreated or 17-DMAG-treated cells and reduced mitochondrial membrane potential (MMP) of A2780cis cells with more significant decline after combined treatment. In this regard, the incubation of A2780cis cells with thiazine[6,5-b]indole induced PARP protein cleavage as well as an increased level of Bad protein with more pronounced changes after combined treatment. Importantly, Hsp70 protein was not upregulated in A2780cis cells neither by individual treatment nor by mutual combination. Our results signify antiproliferative and pro-apoptotic effects of novel thiazine[6,5-b]indole potentiated by Hsp90 inhibitor 17-DMAG in ovarian adenocarcinoma cells resistant to cisplatin and therefore represents new strategy in cancer treatment.
authors.affiliation: Institute of Pharmacology, Faculty of Medicine, P. J. Šafárik University in Košice, 04001 Košice, Slovak Republic.
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Solárová
authors.affiliation: Institute of Pharmacology, Faculty of Medicine, P. J. Šafárik University in Košice, 04001 Košice, Slovak Republic.
authors.forename: Martin
authors.initials: M
authors.lastname: Kello
authors.affiliation: Institute of Pharmacology, Faculty of Medicine, P. J. Šafárik University in Košice, 04001 Košice, Slovak Republic.
authors.forename: Lenka
authors.initials: L
authors.lastname: Varinská
authors.affiliation: Department of Organic Chemistry, Institute of Chemical Sciences, Faculty of Science, P. J. Šafárik University in Košice, 04001 Košice, Slovak Republic.
authors.forename: Mariana
authors.initials: M
authors.lastname: Budovská
authors.affiliation: Laboratory of Cell Biology, Institute of Biology and Ecology, Faculty of Science, P. J. Šafárik University in Košice, 04001 Košice, Slovak Republic. Electronic address: peter.solar@upjs.sk.
authors.forename: Peter
authors.initials: P
authors.lastname: Solár
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy*; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology*; D016227:Benzoquinones / Q000494:pharmacology; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002945:Cisplatin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D018841:HSP90 Heat-Shock Proteins / Q000037:antagonists & inhibitors* / Q000378:metabolism; D006801:Humans; D007211:Indoles / Q000737:chemistry / Q000494:pharmacology*; D047029:Lactams, Macrocyclic / Q000494:pharmacology; D010051:Ovarian Neoplasms / Q000188:drug therapy*; D013843:Thiazines / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C000614274:2-(4'-fluorophenylamino)-4H-1,3-thiazine(6,5-b)indole; D000970:Antineoplastic Agents; D016227:Benzoquinones; D018841:HSP90 Heat-Shock Proteins; D007211:Indoles; D047029:Lactams, Macrocyclic; D013843:Thiazines; C448659:17-(dimethylaminoethylamino)-17-demethoxygeldanamycin; D002945:Cisplatin
keywords: 17-DMAG; A2780cis; Cisplatin resistance; Thiazine[6,5-b]indole