Revealing the fate of cell surface human P-glycoprotein (ABCB1): The lysosomal degradation pathway

摘要: P-glycoprotein (P-gp) transports a variety of chemically dissimilar amphipathic compounds including anticancer drugs. Although mechanisms P-gp drug transport are widely studied, the pathways involving its internalization poorly understood. The present study is aimed at elucidating involved in degradation cell surface P-gp. fate was determined by biotinylating proteins followed flow cytometry and Western blotting. Our data shows that half-life endogenously expressed 26.7±1.1 h human colorectal cancer HCT-15 cells. Treatment cells with Bafilomycin A1 (BafA1) vacuolar H+ ATPase inhibitor increased to 36.1±0.5 h. Interestingly, treatment proteasomal inhibitors MG132, MG115 or lactacystin alone did not alter protein. When were treated both lysosomal (BafA1 MG132), further prolonged 39-50 Functional assays done rhodamine 123 calcein-AM, fluorescent substrates P-gp, indicated function affected either biotinylation BafA1 inhibitors. Immunofluorescence studies antibody against marker LAMP1 P-gp-specific UIC2 permeabilized intracellular primarily localized compartment. results suggest system could be targeted increase sensitivity P-gp- expressing towards chemotherapeutic