Serum Starvation Sensitizes Anticancer Effect of <i>Anemarrhena asphodeloides</i> via p38/JNK-Induced Cell Cycle Arrest and Apoptosis in Colorectal Cancer Cells

Abstract

The molecular mechanism underlying the anticancer effects of <i>Anemarrhena asphodeloides</i> (<i>A. asphodeloides</i>) on colon cancer is unknown. This is the first study evaluating the anticancer effect of <i>A. asphodeloides</i> extract (AA-Ex) in serum-starved colorectal cancer cells. Changes in cell proliferation and morphology in serum-starved MC38 and HCT116 colorectal cancer cells were investigated using MTS assay. Cell cycle and apoptosis were investigated using flow cytometry, and cell cycle regulator expression was determined using qRT-PCR. Apoptosis regulator protein levels and mitogen-activated protein kinase (MAPK) phosphorylation were assessed using western blotting. AA-Ex sensitively suppressed proliferation of serum-starved colorectal cancer cells, with MC38 and HCT116 cells showing greater changes in proliferation after treatment with AA-Ex under serum starvation than HaCaT and RAW 264.7 cells. AA-Ex inhibited cell cycle progression in serum-starved MC38 and HCT116 cells and increased the expression of cell cycle inhibitors (p53, p21, and p27). Furthermore, AA-Ex induced apoptosis in serum-starved MC38 and HCT116 cells. Consistently, AA-Ex suppressed the expression of the anti-apoptotic molecule Bcl-2 and upregulated pro-apoptotic molecules (cytochrome c, cleaved caspase-9, cleaved caspase-3, and cleaved-PARP) in serum-starved cells. AA-Ex treatment under serum starvation decreased AKT and ERK1/2 phosphorylation in the cell survival signaling pathway but increased p38 and JNK phosphorylation. Furthermore, AA-Ex treatment with serum starvation increased the levels of the transcription factors of the p38 and JNK pathway. Serum starvation sensitizes colorectal cancer cells to the anticancer effect of <i>A. asphodeloides</i>via p38/JNK-induced cell cycle arrest and apoptosis. Hence, AA-Ex possesses therapeutic potential for colon cancer treatment.