Intercellular Transfer Of P-glycoprotein Mediated Human Bladder Cancer BIU-87Cells Form A Stable Multi-drug Resistance

Multidrug resistance (MDR), a significant impediment to the successful treatmentof cancer clinically, has been attributed to the overexpression of P-glycoprotein (P-gp),a plasma membrane multidrug efflux transporter. Recently,“non-genetic”acquisitions of MDR by Intercellular transfer of P-gp have been pointed out. In arecent work we concluded that Bladder cancer cells (BIU-87) can acquire functionalP-glycoprotein through a non-genetic mechanism that does not require direct cellcontact. In the present study, BIU-87was co-cultured with adriamycin-resistantderivative cells BIU-87/ADM in Transwell culture system for24、48、72、96hours.The presence of P-glycoprotein in recipient cell membranes (in the Transwell lowerchamber, namely acquired resistance cells: AqMDR) was followed by confocalmicroscopy. Cell counting draw BIU-87/ADM、BIU-87、co-cultured96h AqMDRtheir growth curve and compare their doubling time with and without1μg/mladriamycin culture medium. The co-cultured96h AqMDR were then harvested for thesubsequent culture in the presence or absence of1μg/ml adriamycin. CCK-8, WesternBlot, RT-PCR, Flow Cytometry were used to detect resistance index (RI), P-gpexpression, MDR1mRNA expression levels and intracellular fluorescence intensity ofrhodamine123in the AqMDR cells of0,4,8,16,20-generation and frozen a monthafter the recovery. We show the amount of functional P-glycoprotein in pace withadriamycin-resistant derivative cells BIU-87/ADM and sensitive cell lines BIU-87co-cultured time gradually increased, and AqMDR cells can stability grow at exceedsthe IC50of the drug-sensitive lines and normally leads to an almost complete growthinhibition and subsequent death of BIU-87. In addition, with this concentration,AqMDR cells was able to maintain its resistance and gradually developed into astable resistant cells. Our findings supply transitionally resistant AqMDR cells willgradually develop into stability resistant cells, These findings complement theformation mechanism of MDR and indicate that new treatment strategies designed toovercome MDR.