Benzothiazole derivative bearing amide moiety induces p53-mediated apoptosis in HPV16 positive cervical cancer cells.

In our previous study, we screened the anti-cancer properties of 10 benzothiazole derivatives in cervical cancer cell lines. In the present study, we aimed to delineate the mechanism of the apoptotic pathway (whether intrinsic or extrinsic) following the treatment of N-(4-(benzo[d]thiazol-2-yl)phenyl)-5-chloro-2-methoxybenzamide (named as A-07) on cervical cancer cell lines. Cellular stress by reactive oxygen species was measured using DCFDA dye by flowcytometry. Protein expression and localization was checked by immunofluorescence for γH2A.X, TP53, and CASP-3. Expression profiles of BAX and BCL-2 was done by semi-quantitative RT-PCR and PARP-1 (Poly(ADP-ribose) polymerase-1) by Western blot analysis. Bioinformatic studies were done using PDB websites, metaPocket 2.0 server, YASARA software and Discovery Studio 3.5 Visualizer. We demonstrate that the compound A-07 leads to ROS generation and double strand breaks in SiHa and C-33A cells. The induction of apoptosis in SiHa cells is associated with increased nuclear expression of the tumor suppressor protein, TP53. The shift in BAX/BCL-2 ratio, increased expression of Caspase-3 and cleaved Poly(ADP-ribose) polymerase-1 favour apoptotic signal in SiHa. In silico studies revealed that A-07 has inhibiting capabilities to the E6/E6AP/P53 complex. Our data suggest that treatment of A-07 causes p53 and caspase dependent apoptosis in HPV 16 infected SiHa cells.