MicroRNA 506 regulates expression of PPAR alpha in hydroxycamptothecin-resistant human colon cancer cells.

Chemotherapeutic drug resistance remains a major obstacle to the successful treatment of colon cancer. Here, we show that 77 differentially expressed miRNAs were identified in SW1116/HCPT versus SW1116, and over-expressed miR-506 in SW1116/HCPT cells was validated. Then it was indicated that PPARα is a common target of miR-506 by using a luciferase reporter assay. Our results also demonstrated that cytotoxic ability of HCPT requires the concomitant presence of PPARα, and that loss of PPARα expression imparts resistance to HCPTs anti-tumor effects. All together, our studies indicate that miR-506 over-expression in established HCPT-resistant colon cancer cell line confers resistance to HCPT by inhibiting PPARα expression, then providing a rationale for the development of miRNA-based strategies for reversing resistance in HCPT-resistant colon cancer cells.