Histone Deacetylase inhibitor, LBH589, has antitumor effects on undifferentiated pleomorphic sarcoma cells via the downregulation of FOSL1

Background Epigenetic mutations are involved in oncogenesis and therefore their regulator Histone deacetylaces (HDACs) can be a therapeutic target. In this study, we investigated the anticancer effect and mechanism of pan-HDAC inhibitor, LBH589, against undifferentiated pleomorphic sarcoma (UPS). Method To elucidate the molecular target, we performed RNA microarray for UPS cells after treated LBH589. Data were validated by RT-PCR and Westernblot. Result We found that LBH589 decrease the expression of Fos-like 1 (FOSL1) gene in four UPS cell lines. Knockdown of FOSL1 by RNA interference inhibited cell proliferation and conversely, overexpression increased cell proliferative capacity. Furthermore, we showed that knockdown of FOSL1 cause elevation of p21 expression in UPS cells. Conclusion FOSL1 codes the FRA-1 protein and forms activator protein-1 (AP-1) complexes in collaboration with members of the JUN family to drive gene transcription. FOSL1 is overexpressed in several malignant tumors and considered to be a poor prognostic factor. In this study, we showed that the antitumor effect by HDAC inhibitor is partly due to down regulation of FOSL1. Human undifferentiated pleomorphic sarcoma cell line, GBS-1, was treated with LBH589 and change of gene expression was measured at 0, 12, and 24 hours. One independent sample were examined at each time.