Özgün Heterosiklik Bileşiklerin Glutatyon Transferaz P1-1 İnhibitörleri Olarak Araştırılması ve İnsan Meme Kanser Hücreleri Üzerine Etkilerinin Değerlendirilmesi

Abstract

The aim of this project is to design inhibitors for GST P1-1 and test their effectiveness on breast cancer cells. For this purpose benzoxazole, benzimidazole, benzothiazole derivative compounds were synthesized. Recombinant hGST P1-1 expressed in E.coli were purified and used in the inhibiton kinetics studies. The most effective inhibitor for hGST P1-1 was selected and named as compound-75 (N-[2-(4- Chloro-benzyl)-benzooxazol-5-yl]-4-nitro-benzene-sulfonamide) with an approximately 10 μM IC50 value. This compound shows mixed inhibition for GSH and uncompetitive inhibiton for CDNB with the Ki 6.05 μM and 11.83 μM respectively. For the cell culture studies, GST P1-1 expressing MCF-12A and MDA-MB-231 and not expressing MCF-7 and MDA-MB-468 cell lines were selected. After determining the subtoxic dose of compound-75 and reference molecule docetaxel for each cell, apoptosis, cell cycle and proliferation effects and GST activities were observed. In all cell lines, compound-75 and docetaxel decreased cell viabilities and in combined use of compound-75 with subtoxic dose of docetaxel there is additive effect on MCF-12A and MCF-7 cells. In cell cycle experiments, cell cycle arrest is detected for docetaxel and combined use of drugs in all cell lines except MDA-MB-468 and for the compound-75 in MCF- 12A and MCF-7. According to apoptosis results, single use of docetaxel in MDAMB- 231 and combined use of docetaxel-effective compound in MCF-7 showed %19.7 and %21.35 apoptosis in sub G1 peaks, respectively. These results suggest that apoptosis is occured in different ways independantly from the GST P1-1. The total protein content of cells incubated with the active compound was decreased %45 and the enzyme specific activities were also decreased %40 compared to controls. To observe this change in specific activity of enzyme cell lyzate, the effective-compound should enter the cell, accumulate and effect GST P1-1 level.