Reversal of methotrexate resistance in human squamous carcinoma cells by SQM1-liposome

SQM1, a membrane protein associated with methotrexate (MTX) transport was i ncorporated into unilamellar vesicles, forming SQM1-Liposome. Human squamou s carcinoma of the head and neck (SqCHN) cells resistant to MTX with defect ive MTX transport and low SQM1 expression were treated with SQM1-Liposome. SQM1 content was found to be increased in these treated SqCHN cells by radi oimmunoassay. Concurrent increases in MTX uptake and MTX cytotoxicity in th ese treated SqCHN cells were found. The ability to reverse MTX-resistance i n vitro opens further possibilities for in vivo applications.