Abstract

We investigated the anticancer potential of 5-amino-2-[p-bromophenyl]-benzoxazole [BB] which is a new benzoxazole derivative in different breast cancer cell lines. BB was applied to estrogen receptor positive [ER+] MCF-7 and receptor negative [ER-] MDA-MB cell lines and its effects were determined by histopathological examinations, viability test [MTT], immunocytochemistry assays [Tunnel, VEGF and eNOS]. Moreover, its effects on apoptozis-related proteins such as Apaf-1, cytochrome C, caspase-3, bcl-2 and NF-κB were examined by western blot. Histopathological examinations showed that BB killed many cells for both cancer cell line while the cells lost their adhesion in MCF-7 and lost their adhesion and epiteloid morphology in MDA-MB. MTT analyses demonstrated that BB caused a clear dose depended toxic effect for both cell types. BB application resulted in an increase labeled apoptotic cells after Tunnel staining which was more obvious for MDA-MB compared to that of MCF-7. VEGF staining was decreased after BB application in both cell lines. The decrease of VEGF staining was clearer for MDA-MB compared to that of MCF-7. The status of oxidative stress was shown by eNOS immunocytochemistry which was increase after BB application in both cell lines. The levels of Apaf-1 and bcl-2 were found to be similar while caspase 9 and NF-κB levels were decreased compared to the control group after BB application for both cell lines. On the other hand, cytochrome C levels were slightly increased in MCF-7 cells while this increase was found very obvious in MDA-MB cell lines in BB groups. In conclusion, BB which is a new benzoxazole derivative have shown significant anticancer effects by increasing apoptosis and decreasing angiogenesis in MCF-7 or MDA-MB breast cancer cell lines. These effects of BB seem to be more prominent for [ER-] MDA-MB cell lines which mimic more aggressive type of breast cancer. These results suggest that BB may be useful to treat [ER-] breast cancers and may be added to treatment protocols.

Key words: Benzoxazole derivative, breast cancer, apoptosis, angiogenesis