Apoptosis induction by an analog of curcumin (BDMC-A) in human laryngeal carcinoma cells through intrinsic and extrinsic pathways

Head and neck cancer is the sixth most frequently occurring cancer worldwide and accounts for about 2 % of all cancer-related deaths annually. Curcumin is a well-known chemopreventive agent, and apoptosis induction by curcumin has been reported in many cancer cell types. We synthesized an ortho-hydroxy substituted analog of curcumin, bisdemethoxycurcumin analog (BDMC-A), and aimed to demarcate the apoptotic effects induced by BDMC-A on human laryngeal cancer Hep-2 cells and to compare these effects with those induced by curcumin. We evaluated the apoptotic effects of BDMC-A in comparison to those of curcumin on Hep-2 cells by performing Western blotting, RT-PCR, fluorescent staining and DNA fragmentation assays. In addition, we carried out an in silico molecular docking study on the EGFR kinase domain. We found that BDMC-A can induce apoptosis in Hep-2 cells by regulating the expression of both intrinsic and extrinsic apoptotic proteins, i.e., Bcl-2, Bax, apoptososme complex and death receptors, more efficiently than curcumin. We also observed increased nuclear fragmentation and chromatin condensation after BDMC-A treatment compared to curcumin treatment. Depolarized mitochondria and ROS generation was well pronounced in both BDMC-A and curcumin treated Hep-2 cells. Our in silico molecular docking study on the EGFR kinase domain revealed that BDMC-A may dock more efficiently than curcumin. From our results we conclude that BDMC-A can induce apoptosis in Hep-2 laryngeal carcinoma cells more effectively than curcumin, and that this activity can be attributed to the presence of a hydroxyl group at the ortho position within this compound.