Abstract
Elucidation of the mechanisms underlying multidrug resistance (MDR) is required to ensure the efficacy of chemotherapy against gastric cancer (GC). To investigate this issue, here we identified that microRNA-765 (miRNA-765) is up-regulated both in MDR GC cell lines and in specimens from patients who are not responding to chemotherapy. In addition, down-regulation of miRNA-765 increased the sensitivity of GC cells to anticancer drugs, whereas its overexpression had the opposite effect. Moreover, miRNA-765 suppressed drug-induced apoptosis and positively regulated the expression of MDR-related genes. Finally, we showed that the basic leucine zipper ATF-like transcription factor 2, a tumor suppressor gene, is the functional target of miRNA-765. In summary, these results suggest that miRNA-765 may promote MDR via basic leucine zipper ATF-like transcription factor 2 in GC cells.