Abstract 295: PPARγ-induced KLF4 in regulation of cell growth and migration in human hepatoma cells.

Abstract

Abstract Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide. Recently, a zinc finger transcription factor Krüppel-like factor 4 (KLF4) was found to be reduced in tumors of HCC patients. Additionally, results from our laboratory showed that overexpressed KLF4 repressed epithelial-mesenchymal transition (EMT) process and cell motility by induction of E-cadherin expression and reduction of EMT markers in hepatoma cells. Interestingly, it has been found that PPARγ agonists upregulated KLF4 in colorectal cancer cells. However, the mechanism of PPARγ-induced KLF4 in the EMT process of HCC remains unclear. In this study, Hep3B, PLC/PRF/5, and Mahlavu human hepatoma cells were treated with PPARγ agonists rosiglitazone, troglitazone, and PPARγ antagonist GW9662, respectively. After rosiglitazone or troglitazone treatment for various time periods, growth inhibition was observed in both Hep3B and PLC/PRF/5 cells at 48 hours by surforhodamine B assay. Mahlavu cells showed less response to rosiglitazone and troglitazone treatment as compared to the other two cell lines. However, pretreatment of GW9662, a PPARγ antagonist, prior to PPARγ agonists treatment did not block the PPARγ agonists-induced cell growth inhibition. Moreover, cotreatment of PPARγ agonist and antagonist showed additive growth inhibition effect. In addition, rosiglitazone and troglitazone inhibited the migration of Hep3B, PLC/PRF/5 and Mahlavu cells differentially in transwell assay. Western blotting analysis showed upregulation of KLF4 and E-cadherin in Hep3B and PLC/PRF/5 cells after rosiglitazone and troglitazone treatment. Interestingly, decreased KLF4 and E-cadherin were observed in Hep3B, PLC/PRF/5, and Mahlavu cells after GW9662 treatment, indicating that the regulation of KLF4 and E-cadherin were PPARγ-dependent. Moreover, GW9662 also inhibited cell migration of Hep3B, PLC/PRF/5, and Mahlavu cells, with a concomitant decrease of vimentin. These results together suggested that PPARγ agonists and antagonist not only inhibited the growth but also decreased migration of hepatoma cells. Modulation of the PPARγ agonists induced expression of KLF4 and E-cadherin played important role in migration of hepatoma cells. Citation Format: Hui-Tzu Hsu, Ming-Ta Sung, Chin-Wen Chi. PPARγ-induced KLF4 in regulation of cell growth and migration in human hepatoma cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 295. doi:10.1158/1538-7445.AM2013-295