Heptaphylline suppresses the proliferation and migration of human bladder cancer cells via induction of intrinsic apoptosis, autophagy and inhibition of β-catenin signalling pathway

Purpose: Heptaphylline has been shown to suppress the growth of different types of cancer cells. Nonetheless, the anticancer effects of Heptaphylline have not been examined against human bladder cancer cells. Against this backdrop, this study was undertaken to investigate the anticancer effects of the carbazole alkaloid Heptaphylline against human bladder cancer cells. Methods: Proliferation rate was determined by MTT assay. Apoptosis was demonstrated by DAPI and annexin V/propidium iodide (PI) assay. Electron microscopy was used for autophagy detection. Western blot analysis was used to determine protein expression. Results: The results showed that Heptaphylline suppressed the proliferation of the RT4 bladder cancer cells and exhibited an IC50 of 25 mu M. The toxic effects of Heptaphylline were comparatively lower on the normal Hs172.T cells, as evidenced from the IC50 of 95 mu M. The wound healing assay showed that Heptaphylline suppressed the migration of the RT4 bladder cancer cells. The DAPI and annexin WPI staining showed that Heptaphylline induced apoptosis in the RT4 bladder cancer cells which was also accompanied by enhancement in the cleavage of PARR caspase-3 and caspase-9. Additionally, Heptaphylline caused increase in Bax and decrease in Bcl-2 expression. Electron microscopic analysis showed that Heptaphylline also caused autophagy in the RT4 cells which was associated with increase in LC3, Atg5, Atg7 and Beclin-1 expression and decrease in p62 expression. This molecule also blocked the P-catenin signalling pathway in the RT4 bladder cancer cells. Conclusion: Taken together, Heptaphylline suppressed the proliferation of the bladder cancer cells and may prove beneficial in the bladder cancer treatment.