Tim-3 expression in glioma cells is associated with drug resistance

ABSTRACT

Objective: T-cell immunoglobulin and mucin-domain containing-3 (Tim-3) has been widely recognized as a negative regulator of antitumor immunity. However, the mechanism by which Tim-3 suppresses antitumor treatment in gliomas remains unclear. This study aims to explore whether Tim-3 is expressed and to evaluate its effect in drug-fasted glioma cells. Subjects and Methods: U87 and U251 glioma cell lines were tested. Cell proliferation activity, cell viability, and the protein and mRNA levels of Tim-3 were detected using CCK-8, flow cytometry, Western blotting, and reverse transcription-quantitative polymerase chain reaction, respectively. Enhancement of the sensitivity of glioma cells to chemotherapeutic agents was tested after inhibiting Tim-3 expression using Tim-3 small interfering RNAs (siRNA). Results: As temozolomide (TMZ) concentration increased, the ratio of apoptotic cells also increased accordingly. However, the level of Tim-3 expression in living cells from the high-dose group was higher than in the low- and middle-dose groups. After interfering with the expression of Tim-3 using siRNA against Tim-3, the killing effect of TMZ rose through an increase in apoptosis. Conclusions: The presence of Tim-3 mRNA and protein in glioma cells was detected. Significantly, knocking down Tim-3 expression improved the potential of TMZ treatment.