Cytotoxic n-Hexane Fraction of the Egyptian Pteris vittata Functions as Anti-breast Cancer Through Coordinated Actions on Apoptotic and Autophagic Pathways.

Abstract

We investigated the possible anticancer mechanisms of Pteris vittata [PV] n-hexane extract on MCF-7 [breast cancer cell line]. Cultured cell lines were treated with various concentrations of this extract ± Baf-A1 [autophagic inhibitor]. Cells' viability, apoptotic markers [caspase-7, Bax, and Bcl-2], autophagic markers [light chain 3 [LC-3] and P62/SQSTM1]], and the tumor suppressor P53 and its mRNA were checked by their corresponding methods. Treated cell lines showed significant concentration and time-dependent reductions in cell viability in response to PV-n-hexane extract and also exhibited a concomitant induction of apoptosis [increased chromatin condensation, nuclear fragmentation, and pro-apoptotic Bax, and cleaved caspase-7 levels while decreased Bcl-2 levels] and autophagy [increased autophagosomes vacuoles, and LC3B II levels while decreased P62/SQSTM1 levels]. Moreover, PV-n-hexane extract-treated cells showed significant increases in the P53 and its mRNA levels. The addition of Baf-A1 reversed the PV-n-hexane extract autophagic effects and increased apoptotic cell percentage with a much increase in the cleaved caspase-7 and P53 protein and its mRNA levels. We concluded that the PV-n-hexane extract exhibits cytotoxic effects on the MCF-7 cell line with significant reductions in cell viability and concomitant autophagy and apoptosis induction. Inhibition of autophagy in the PV-treated MCF-7 cells enhances apoptosis via a p35-dependent pathway.