Determination of Phenyl Butyrate effects on increasing sensitivity or overcoming resistance to Oxaliplatin in colon cancer cells; an in-vitro study

Abstract

Considering the prevalence of colorectal cancer during recent decades and rising resistance to chemotherapy drugs, especially Oxaliplatin; it is necessary to increase the efficacy of conventional methods. Therefore Phenyl-butyrate (as a derivate of Short Chain Fatty Acids) was studied here to determine its effects on increasing sensitivity or overcoming resistance to Oxaliplatin in colon cancer cell lines. Purpose: Determination of Phenyl Butyrate effects on increasing sensitivity or overcoming resistance to Oxaliplatin in colon cancer cells; an in-vitro study Procedure: Colon cancer cell lines (Caco-2, HT-29), normal endothelial (HUVEC) and normal epithelial (KDR) cell lines were grown in RPMI 1640 medium supplemented with 10% FBS and maintained at 37° in 5% CO2 incubator. The IC50 of Oxaliplatin and Phenyl-Butyrate was measured by MTT assay in all cell lines. Oxaliplatin-resistant cell lines were acquired by continues exposure to stepwise increasing concentrations of Oxaliplatin. Then the cells were treated by different mixtures of Oxaliplatin and Phenyl-Butyrate to achieve the most desirable combination. The effects of the combination were studied by DAPI staining and Flow cytometry assays. Findings: It is indicated that the HT-29 cell line was inherently more resistant than Caco-2 cell line to Oxaliplatin, but showed the opposite result to Phenyl-Butyrate. Also normal cell lines were inherently more resistant than cancerous cell lines to Phenyl-Butyrate. The combination of Oxaliplatin-Phenyl-Butyrate treatment resulted in synergistic effect in HT-29 cell line but not in Caco-2. Finally the effects of the combination on Oxaliplatin-resistant cell lines were equal to Phenyl-Butyrate effects. Conclusion: Phenyl-Butyrate is able to increase the efficacy of Oxaliplatin in colon cancer. But it is better to optimize the parameters of time and dose of combination.