BACKGROUND & OBJECTIVE: Nowadays, reversing the multidrug resistance (MDR) of thermotolerant carcinoma cells is a hot topic in tumor thermatology. This study was to investigate the adriamycin (ADR)-resistance of thermotolerant hepatocarcinoma cell line HepG2/thermotolerance and the effect of neferine (Nef) on the ADR-resistance of HepG2/thermotolerance cells. METHODS: Cell proliferation was measured by MTT assay. Cell apoptosis was detected by flow cytometry (FCM) with PI staining. The expression of Bcl-2 was measured by FCM using fluorescein isothiocyanate (FITC)-conjugated anti-bcl-2 antibodies. RESULTS: The proliferation rate and apoptosis rate of HepG2/thermotolerance cells cultured in 43 degrees C for 24 h were (89.6+/-5.4)% and (13.6+/-5.4)%, respectively; however, those of HepG2 cells were (23.9+/-3.6)% and (68.9+/-7.3)%, respectively. The 50% inhibition concentration (IC50) of ADR was 10.8 times higher for HepG2/thermotolerance cells than for HepG2 cells [(113.7+/-12.7) micromol/L vs. (10.5+/-2.3) micromol/L]. When treated with 1, 10, 100 micromol/L ADR at 37 degrees C for 24 h, the apoptosis rates of HepG2/thermotolerance cells were (9.3+/-2.6)%, (17.8+/-7.3)%, and (32.9+/-8.6)%, respectively, but those of HepG2 cells were (14.3+/-3.9)%, (38.9+/-6.8)%, and (62.7+/-5.9)%, respectively. In the presence of 10 and 40 micromol/L Nef, the IC50 of ADR for HepG2/thermotolerance cells was significantly decreased from (113.7+/-12.7) micromol/L to (63.7+/-5.6) micromol/L and (16.8+/-2.8) micromol/L, and the cell apoptosis induced by 10 micromol/L ADR was significantly increased from (17.8+/-4.3)% to (26.8+/-5.9)% and (34.9+/-8.7)%, respectively. Bcl-2 was overexpressed in HepG2/thermotolerance cells, whereas it was down-regulated when the cells were treated with 40 micromol/L Nef for 24 h. CONCLUSIONS: HepG2/thermotolerance cells are ADR-resistant. Nef may reverse the ADR-resistance of HepG2/thermotolerance cells by down-regulating Bcl-2 expression.
BACKGROUND & OBJECTIVE: Nowadays, reversing the multidrug resistance (MDR) of thermotolerant carcinoma cells is a hot topic in tumor thermatology. This study was to investigate the adriamycin (ADR)-resistance of thermotolerant hepatocarcinoma cell line HepG2/thermotolerance and the effect of neferine (Nef) on the ADR-resistance of HepG2/thermotolerance cells. METHODS: Cell proliferation was measured by MTT assay. Cell apoptosis was detected by flow cytometry (FCM) with PI staining. The expression of Bcl-2 was measured by FCM using fluorescein isothiocyanate (FITC)-conjugated anti-bcl-2 antibodies. RESULTS: The proliferation rate and apoptosis rate of HepG2/thermotolerance cells cultured in 43 degrees C for 24 h were (89.6+/-5.4)% and (13.6+/-5.4)%, respectively; however, those of HepG2 cells were (23.9+/-3.6)% and (68.9+/-7.3)%, respectively. The 50% inhibition concentration (IC50) of ADR was 10.8 times higher for HepG2/thermotolerance cells than for HepG2 cells [(113.7+/-12.7) micromol/L vs. (10.5+/-2.3) micromol/L]. When treated with 1, 10, 100 micromol/L ADR at 37 degrees C for 24 h, the apoptosis rates of HepG2/thermotolerance cells were (9.3+/-2.6)%, (17.8+/-7.3)%, and (32.9+/-8.6)%, respectively, but those of HepG2 cells were (14.3+/-3.9)%, (38.9+/-6.8)%, and (62.7+/-5.9)%, respectively. In the presence of 10 and 40 micromol/L Nef, the IC50 of ADR for HepG2/thermotolerance cells was significantly decreased from (113.7+/-12.7) micromol/L to (63.7+/-5.6) micromol/L and (16.8+/-2.8) micromol/L, and the cell apoptosis induced by 10 micromol/L ADR was significantly increased from (17.8+/-4.3)% to (26.8+/-5.9)% and (34.9+/-8.7)%, respectively. Bcl-2 was overexpressed in HepG2/thermotolerance cells, whereas it was down-regulated when the cells were treated with 40 micromol/L Nef for 24 h. CONCLUSIONS: HepG2/thermotolerance cells are ADR-resistant. Nef may reverse the ADR-resistance of HepG2/thermotolerance cells by down-regulating Bcl-2 expression.