Phyllanthus muellerianus and Ficus exasperata exhibit anti-proliferative and pro-apoptotic activities in human prostate cancer PC-3 cells by modulating calcium influx and activating caspases

Abstract

Phyllanthus muellerianus (PM) and Ficus exasperata (FE) are plants used against cancers. We evaluated the phytochemical pro les and in vitro antioxidant potentials of PM and FE, and investigate their effects on cell proliferation, intracellular calcium ([Ca 2+ ] i ), caspases 3/9, apoptosis, oxidative stress markers, and Bax/cytochrome C expression in PC-3 cells. MethodsThe phytochemical pro les were evaluated by liquid chromatography-mass spectrometry (LC-MS), and the antioxidant by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radicals scavenging method. The cells were incubated for 24 hours with 3% tween 80, paclitaxel (5 nM), PM (800 and 1200 µg/ml), and FE (800 and 1200 µg/ml). After treatments, [Ca 2+ ] i , caspases 3/9, apoptosis and oxidative stress parameters were measured using colorimetric kits, while the mRNA levels of Bax and cytochrome C were quanti ed by RT-qPCR. ResultsNitidine, phloridzin and linoleic acid were identi ed in PM, while docosane, cardanol and chlorogenic acid were revealed in FE. The in vitro antioxidant potential of PM was greater than that of FE. Both plants inhibited the growth of PC-3 cells in a dose-dependent manner, but signi cantly (p<0.5-0.001) increased [Ca 2+ ] i , apoptosis level, caspase 3/9 activities, reactive oxygen species production and lipid peroxidation, compared with control. Moreover, the activities of superoxide dismutase, catalase and glutathione peroxidase were signi cantly decreased in the cells incubated with the plant extracts, PM being the most effective. Paclitaxel, PM and FE upregulated Bax and cytochrome C genes in PC-3 cells. ConclusionPM and FE inhibited the growth of PC-3 cells by modulating the [Ca 2+ ] i and inducing apoptosis through Bax/Cytochrome C/Caspase 3-9 signaling pathway.Although Tang et al. (2010; and Bafor et al. (2017) have reported the bene cial effects of some Phyllanthus sp and F. exasperata, respectively on MeWo prostate cancer and A2780 ovarian cancer cells, their effects on PC-3 cells have not been investigated. We characterized P. muellerianus and F. exasperata extracts by LC-MS analysis and determined their in vitro antioxidant potentials by DPPH assay. With the hypothesis that the phytocomponents revealed in these plants may prevent prostate cancer, we evaluated the effects P. muellerianus and F. exasperata on cell proliferation, [Ca 2+ ] i , apoptosis level, ROS production, caspase 3/9 activities, lipid peroxidation, antioxidant enzymes (SOD, CAT and GSH-Px) and mRNA levels of Bax and cytochrome C in PC-3 cells. Materials And MethodsCollection of P. muellerianus and F. exasperata P. muellerianus roots and the stem barks of F. exasperata were harvested in April 2017 in Tonga (West Cameroon). The plants were identi ed at the Cameroon National Herbarium (CNH) under the voucher number N° BWPV03 (for P. muellerianus) and N° 56091/HNC (for F. exasperata). The roots and stem barks were separately shade-dried for 7 days, later transformed into powder and used for preparation of the methanolic extracts of P. muellerianus and F. exasperata. P...