Mechanism of apoptotic induction in human breast cancer cell, MCF-7, by an analog of curcumin in comparison with curcumin--an in vitro and in silico approach

Abstract

In developing countries, survival rates for breast cancer are poor and it accounts for 22.9% of all cancers in women. Curcumin, a major constituent from turmeric, is one of the well-known chemopreventive agents. Reports have shown that curcumin induces apoptosis in breast cancer cells. We synthesized an ortho-hydroxy substituted analog of curcumin (BDMC-A) and analyzed its cytotoxicity. The BDMC-A inhibited MCF-7 at a dose equivalent to that of curcumin (30 μM). The present study was aimed at delineating the apoptotic mechanism of BDMC-A in comparison to that of curcumin. In our study, BDMC-A exerted more potent effect on the modulation of selective apoptotic markers (intrinsic pathway: p53, Bcl-2, Bax, cyt c, Apaf-1, caspase-9, 3, PARP; extrinsic pathway: FasL, caspase 8) compared to curcumin. mRNA expression studies for Bcl2/Bax also supported the increased efficacy of BDMC-A. An in silico molecular docking study with PI3K revealed that the docking of BDMC-A was more potent compared to curcumin. Increased apoptotic induction by BDMC-A compared to curcumin was also demonstrated by Annexin V, Rh123 (ΔΨm), PI, Hoechst 33258, AO/EB fluorescent staining studies which showed characteristic apoptotic features like nuclear fragmentation and chromatin condensation. Moreover, BDMC-A treated cells effectively induced apoptosis through ROS intermediates compared to curcumin, as measured by 2'-7'-Dichlorodihydrofluorescein diacetate (DCFH-DA). Hence our overall results showed that BDMC-A induced apoptosis more effectively compared to curcumin and the activity can be attributed to the presence of hydroxyl group in the ortho position in its structure. Further researches are going on to delineate its molecular targets to evaluate its effect as a potent anticancer agent.