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

SQM1, a membrane protein associated with methotrexate (MTX) transport was incorporated into unilamellar vesicles, forming. SQM1-Liposome. Human squamous carcinoma of the head and neck (SqCHN) cells resistant to MTX with defective MTX transport and low SQM1 expression were treated with SQM1-Liposome. SQM1 content was found to be increased in these treated SqCHN cells by radioimmunoassay. Concurrent increases in MTX uptake and MTX cytotoxicity in these treated SqCHN cells were found. The ability to reverse MTX-resistance in vitro opens further possibilities for in vivo applications.