Isoform specific changes in PPARα and β in colon and breast cancer with differentiation

To investigate the role of peroxisome proliferator-activated receptors (PPARs) α and β in the differentiation of colon cancer cells, we differentiated HT-29 cells using sodium butyrate (NaB) and culturing post-confluence and assessed differentiation using the marker intestinal alkaline phosphatase. While PPARα levels only changed with culturing post confluence, PPARβ levels increased independent of the method of differentiation. To explore further the differences induced by NaB, we assessed changes in both PPAR isoforms in MCF-7 breast cancer cells cultured in the presence of NaB over 48 h. Again a very different expression pattern was observed with PPARα increasing after 4 h and remaining elevated, while PPARβ increased transiently. Our studies suggest that the expression of PPARs is dependent upon both the method of differentiation and on time. Moreover, these studies show that changes in PPARα levels are not required for the differentiation of colon cancer cell lines, whereas changes in PPARβ are more closely associated with differentiation.