Extract of Cycas revoluta Thunb. enhances the inhibitory effect of 5-fluorouracil on gastric cancer cells through the AKT-mTOR pathway

Figure 1 Cycas revoluta Thunb. extract effectively inhibits gastric cancer cell growth. A: Dose-response assays of the extract. Gastric cancer cells were analyzed after treatment with increasing concentrations of the extract for 24 h. The percentage of cell viability was normalized to the control, and three independent experiments were performed for calculating ± STDEV; B: Half-maximal effective concentration and the half-maximal lethal concentration for each cell line. EC50: Half-maximal effective concentration; LC50: Half-maximal lethal concentration.

Figure 2 The effect of Cycas revoluta Thunb. natural extract on cell migration and invasion. A: Wound healing assays; and B: transwell invasion assays were performed with a low dose of extract (60 μg/mL). The wound width or migrated cells normalized to the control is shown in histograms, and the error bars represent ± STDEV from n = 3 independent experiments, ^bP < 0.01.

Figure 3 The chemosensitization of Cycas revoluta Thunb. natural extract with 5-fluorouracil. A: Clonogenic assays. The error bars represent ± STDEV from n = 3 independent experiments, ^bP < 0.01; B: Dose-response assays of 5-fluorouracil (5-Fu) with the extract; C: The half-maximal effective concentration and the half-maximal lethal concentration of 5-Fu in combination with the extract. The error bars represent ± STDEV from n = 3 independent experiments; D: Western blot analysis of drug-resistance-related proteins. GAPDH was used as a control. Relative expressions are shown in the left histogram, and the error bars represent ± STDEV from n = 3 independent experiments ^aP < 0.05, ^bP < 0.01. 5-Fu: 5-fluorouracil; EC50: Half-maximal effective concentration; LC50: Half-maximal lethal concentration; mTOR: Mammalian target of rapamycin; P-gp: P-glycoprotein.

Figure 4 The mechanism of chemosensitization mediated by Cycas revoluta Thunb. extract. A: Hoechst 33258 staining to confirm apoptosis induced by 5-fluorouracil and the extract. The error bars represent ± STDEV from n = 3 independent experiments ^aP < 0.05, ^bP < 0.01; B: Western blot analysis of apoptosis-related proteins. Relative expressions are shown in the left histogram, and the error bars represent ± STDEV from n = 3 independent experiments ^aP < 0.05, ^bP < 0.01. 5-Fu: 5-fluorouracil; XIAP: X-linked inhibitor of apoptosis protein; AIF: Apoptosis inducing factor.