Intercellular Transfer Of P-glycoprotein In Bladder Cancer Cell Line BIU-87Drug Resistant Cells And Drug Sensitive Cells

Objective P-glycoprotein is an ATP-driven efflux pump，which transports a widevariety of antineoplastic drug from cell interior to extracellular space, which leads tothe failure of cancer chemotherapy. To investigate whether there is intercellulartransfer of functional P-glycoprotein(P-gp)from resistant to sensitive cellsubpopulations in vitro and P-gp associated with the mdr1.Methods The expression of P-gp were detected by flow cytometry(FCM). Thesensitive BIU-87cells stained by Hoechst33342(BIU-87/Hoechst33342)，wereco-cultured with BIU-87/ADM cells，an adriamycin-resistant cell line derived fromBIU-87cells．The distribution of P-gp in BIU-87cells was observed under laserscanning confocal microscope(LSCM)．The cells in transwell lower chambers werecollected from co-cultured system．The abundance of P-gp was analyzed by westernblot, and the expression of mdrl mRNA was detected by RT-PCR．The transportingfunction of P-gp was determined by Rhodamine123assay．Results Under laser scanning confocal microscope，nucleolus of BIU-87/aqMDR ismainly based on blue fluorescence，a little green fluorescence in cell membrane andcytoplasm，green fluorescence was detected in BIU-87/ADM cells．blue fluorescencewas detected in BIU-87/Hoechst33342cells． The level of P-gp protein inBIU-87/aqMDR cells was lower than that in BIU-87/ADM cells，but higher than thatin BIU-87/Hoechst33342cells(P<0．05)and BIU-87cells (P<0．05) by Western blotanalysis．The expression of mdr1mRNA in BIU-87/ADM cells was higher than thatin BIU-87/aqMDR，BIU-87and BIU-87/Hoechst33342cells（P＜0.05)，but therewas no significant difference in mdr1mRNA among BIU-87/aqMDR，BIU-87andBIU-87/Hoechst33342cells(P>0．05). Mean fluorescence intensity in BIU-87/aqMDR was higher than that in BIU-87/ADM（P＜0.05)，but lower than inBIU-87（P＜0.05) by Rh123assay.Conclusions P-gp can transfer from drug resistant human bladder cancer cells tosensitive human bladder cancer cells, and the transferred P-gp maintained itsbiological function. This study provides a novel train of thought for mechanism ofmultidrug resistance in human bladder cancer.