Caspase 3/7 activation during apoptotic cell death of human Rhabdomyosarcoma (RMS) and breast adenocarcinoma (MCF-7) cells induced by different fractions of Chnoospora minima

Abstract

Marine seaweeds are a rich source of bioactive metabolites that can be used as a source for the development of anti-cancer drugs. Apoptosis is a form of programmed cell death involved with the elimination of unwanted cells from the body. Among different mechanisms of apoptosis, caspases are a family of protease enzymes playing an essential role in apoptosis. Therefore, the present study was aimed to determine the caspase 3/7 activation in human rhabdomyosarcoma (RMS) and breast adenocarcinoma (MCF-7) cells following treatment with hexane and chloroform fractions of the seaweed species Chnoospora minima. The apo-one homogenous caspase 3/7 activity of treated cells was evaluated according to the manufacturer`s instructions (G7790, Promega, USA). Polysaccharide depleted polyphenol-rich methanol extract was sequentially partitioned with hexane, chloroform, and ethyl acetate to determine the cytotoxic activity. Based on the results, hexane and chloroform fractions of C.minima were selected to determine the caspase 3/7 activation of human RMS and MCF-7 cells. The caspase 3/7 activation was quantified by relative flurescence unit (RFU). The chloroform fraction (RFU4 hrs:3932.9) of C.minima showed prominent activation of caspase 3/7 in RMS cells after 4 h of caspase treatment more than the hexane fraction (RFU4 hrs:2556.6) compared to the standard Staurosporine (RFU4 hrs:3417.5) and cycloheximide (RFU4 hrs:2950.5). In contrast, hexane (RFU3 hrs:1496.9) and chloroform (RFU3 hrs:1464.7) fractions treated MCF-7 cells showed low caspase 3/7 activation, and the highest activity was observed after 3 h of caspase treatment. Hence, it can be concluded that the hexane and chloroform fractions of C.minima induce apoptosis in RMS cells more prominently via the caspase 3/7 pathway compared to the MCF-7 cells. Therefore, further studies should be conducted to confirm the activity of caspase 3 and 7 via gene expression analysis.