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