The Research Of Intercellular Transfer Of P-Glycoprotein In Hepatocellular Carcinoma Cell Line HepG2

Objective: To investigate whether there is intercellular transfer of functional P-glycoprotein(P-gp) from P-gp-positive cells to P-gp-negative cells in vitro, and the connection between P-gp and multipledrug resistance gene-1(mdr1).Methods: HepG2/GFP cells,a HepG2 hepatocellular carcinoma (HCC) cell line stably expressing GFP, were co-cultured with HepG2/ADM cells, an adriamycin-resistant cell line derived from HepG2 cells. The distribution of P-gp in hepatocellular carcinoma cell was observed under laser scanning confocal microscope (LSCM). To collect HepG2/GFP (HepG2/aqMDR) cells, immunomagnetic beads were used to separate HepG2/GFP cells from the mixed culture. The abundance of P-gp was analyzed by western blot, and the expression of mdr1 mRNA was detected by qRT-PCR.Results: Many stable clones with green fluorescence were detected by with fluorescence microscope. Yellow fluorescence was detected in HepG2/aqMDR cells, green fluorescence was detected in HepG2/GFP cells, and red fluorescence was detected in HepG2/ADM cells by LSCM. The level of P-gp protein in HepG2/aqMDR cells was lower than that in HepG2/ADM cells, but higher than that in HepG2/GFP cells(q=35.07,P<0.05)and HepG2 cells (q=36.87,P<0.05). The expression of mdr1 mRNA in HepG2/ADM cells was higher than that in HepG2/aqMDR, HepG2/GFP and HepG2 cells, but there was no significant difference in mdr1 mRNA among HepG2/aqMDR, HepG2/GFP and HepG2 cells(F=2.30,P>0.05).Conclusions: P-gp can transfer from drug resistant hepatocellular carcinoma cells to sensitive hepatocellular carcinoma cells. The expression of P-gp in sensitive hepatocellular carcinoma cells was up-regulated, but the level of mdr1 mRNA was not up-regulated. This study suggests a novel mechanism of multipledrug resistance in hepatocellular carcinoma.