Patrinia scabiosaefolia Inhibits Growth of 5-FU-Resistant Colorectal Carcinoma Cells via Induction of Apoptosis and Suppression of AKT Pathway.

OBJECTIVE: To investigate the effects of ethanol extract of Patrinia scabiosaefolia (EEPS) on chemo-resistance of colorectal cancer cells (CRC) and explore the possible molecular mechanisms.

METHODS: 5-fluorouracil (5-FU)-resistant human colorectal carcinoma cell line (HCT-8/5-FU) and its parental cells HCT-8 were treated with EEPS (0, 0.25, 0.50, 1 or 2 mg/mL), or 5-FU (0, 100, 200, 400, 800 or 1600 μmol/L). The 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay was performed to evaluate the cell viability. Cell density was observed by phase-contrast microscope, cell counting and colony formation assay were used to determine the cell proliferation of HCT-8/5-FU cells treated with 0, 0.5, 1 or 2 mg/mL EEPS. Cell apoptosis was determined by Hoechst staining. Western-blot was performed to detect the phosphorylation of AKT as well as the protein expression level of B-cell CLL/lymphoma 2 (Bcl-2) and Bcl-2-associated X protein (Bax).

RESULTS: Compared with HCT-8 cells, MTT assay results indicated that HCT-8/5-FU cells were resistant to 5-FU treatment (P<0.05), and sensitive to EEPS treatment (P>0.05). Moreover, compared with untreated HCT-8/5-FU cells, 1 and 2 mg/mL of EEPS treatment significantly reduced cell density, cell number, inhibited cell survival (P<0.05), and induced apoptosis in HCT-8/5-FU cells. Furthermore, 1 and 2 mg/mL of EEPS significantly decreased the phosphorylation level of p-AKT and Bcl-2 protein expression, and increased the expression of Bax protein (P<0.05).

CONCLUSION: EEPS is a promising therapeutic agent that may overcome chemo-resistance in cancer cells, likely through suppression of the AKT pathway and promotion of cancer cell apoptosis.