Finally, the tumor suppressor activity of HDAC6 was experimentally investigated in vivo using cell lines stably overexpressing HDAC6. 3-MA, 3-methyladenine; FACS, fluorescence-activated cell sorting; FBS, fetal bovine serum; GAPDH, BGB324 nmr glyceraldehyde-3-phosphate dehydrogenase;

HAT, histone acetyltransferase; HCC, hepatocellular carcinoma; HDAC, histone deacetylases; JNK, c-Jun NH2-terminal kinase; LC3, microtubule-associated protein 1 light chain 3; mRNA, messenger RNA; MTT, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide; PARP, poly (ADP-ribose) polymerase; siRNA, small interfering RNA; TEM, transmission electron microscopy; TMA, tissue microarray. This study was approved by the Institutional Review of Board (IRB) of the Songeui Campus, College of Medicine, Catholic University of Korea (IRB approval number; CUMC09U117). All animal experiments were performed in compliance with the guidelines of the Institutional Animal Care and Use Committee (IACUC) of the Department of Laboratory Animals, College of Medicine,

Catholic University of Korea. This animal study was also approved by the IRB for the care and use of animals at the Catholic University Medical Center (approval number; CUMC-2009-0050-03). A full description of the Materials and Methods Selleckchem OTX015 are given in the Supporting Information. The overexpression of HDAC6 has been reported in a variety of cancer cell lines and has been found to be required to maintain the transformed phenotypes of a

number of established oncogenic cell lines.15 However, when we analyzed HDAC6 gene expression from the microarray dataset that previously studied different histopathological grades of HCC,16 we noted that HDAC6 gene expression was significantly down-regulated in overt HCC as compared with premalignant lesion, dysplastic nodules (Supporting Fig. 1A). To confirm this, we employed a new subset of HCCs that include primary HCCs, defined by Edmondson grade 1 (TG1, n = 8), grade 2 (TG2, n = 9), grade 3 (TG3, n = 9), and dysplastic nodule (DN, n = 11) and PLEK2 chronic hepatic disease, liver fibrosis (LF, n = 12), and surrounding noncancerous liver tissues (N, n = 11), and subjected to whole genome expression microarrays. As shown in Fig. 1A, HDAC6 gene expression was significantly down-regulated in overt HCC (TG3) as compared with normal or chronic liver disease (LF) or premalignant lesion (DN). This result was supported by immunohistochemical analyses of HCC tissue microarray (Supporting Table 1; Supporting Fig. 1B). Of the 32 normal hepatocyte samples tested, 30 (93.