151. Bortezomib effect on E2F and cyclin family members in human hepatocellular carcinoma cell lines
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Gabriele Pozzato, Rossella Farra, Nicola Fiotti, Barbara Dapas, Sara Chiaretti, Daniele Baiz, Fabrizio Zanconati, Bruna Scaggiante, Lara Consoloni, Gabriele Grassi, Baiz, Daniele, Dapas, Barbara, Farra, Rossella, Scaggiante, Bruna, Pozzato, Gabriele, Zanconati, Fabrizio, Fiotti, Nicola, Consoloni, Lara, Chiaretti, S, and Grassi, Gabriele
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Carcinoma, Hepatocellular ,E2F family ,Brief Article ,Microarray ,Hepatocellular carcinoma ,Antineoplastic Agents ,Hepatic carcinoma ,Biology ,Transfection ,Bortezomib ,immune system diseases ,Cyclins ,hemic and lymphatic diseases ,medicine ,Humans ,RNA, Messenger ,Liver ,26S proteasome ,E2F ,neoplasms ,Cell Proliferation ,Cyclin ,Liver Neoplasms ,Gastroenterology ,Hep G2 Cells ,General Medicine ,medicine.disease ,Boronic Acids ,digestive system diseases ,E2F Transcription Factors ,E2F Family ,Gene Expression Regulation, Neoplastic ,Phenotype ,Proteasome ,Pyrazines ,Cancer research ,RNA Interference ,biological phenomena, cell phenomena, and immunity ,Proteasome Inhibitors ,medicine.drug - Abstract
AIM To evaluate the effects of the proteasome inhibitor Bortezomib (BZB) on E2Fs and related genes in Hepatocellular carcinoma (HCC) cells. METHODS The mRNA levels of the E2F family members (pro-proliferative: E2F1-3 and anti-proliferative: E2F4-8) and of their related genes cyclins and cyclin-dependent kinases (cdks) were evaluated in two HCC cell lines following a single BZB administration. mRNA levels of the epithelial-mesenchymal transition (EMT) genes were also measured in both cell lines after BZB treatment. The BZB concentration (40 nM) used was chosen to stay well below the maximal amount/cm2 recommended for in vivo application, and two days incubation was chosen as this time point has been found optimal to detect BZB effects in our previous studies. The HCC cell lines, HepG2 and JHH6, were chosen as they display different phenotypes, hepatocyte-like for HepG2 and undifferentiated for JHH6, thus representing an in vitro model of low and high aggressive forms of HCC, respectively. The mRNA levels of the target genes were measured by two-color microarray-based gene expression analysis, performed according to Agilent Technologies protocol and using an Agilent Scan B. For the E2F family members, mRNA levels were quantified by RT-PCR. Using small interfering RNA’s, the effects of E2F8 depletion on cell number was also evaluated. RESULTS After BZB treatment, microarray analysis of the undifferentiated JHH6 revealed a significant decrease in the expression of the pro-proliferative E2F member E2F2. Quantitative RT-PCR data were in keeping with the microarray analysis, and showed a significant increase and decrease in E2F8 and E2F2 mRNA levels, respectively. In contrast, BZB treatment of the hepatocyte-like HCC cell line HepG2 had a significant impact on mRNA levels of 5 of the 8 E2F members. In particular, mRNA levels of the pro-proliferative E2F members E2F1, E2F2, and of the anti-proliferative member E2F8, decreased over 80%. Notably, a reduction in E2F8 expression in HepG2 and JHH6 cells following siRNA treatment had no impact on cell proliferation. As observed with JHH6, BZB treatment of HepG2 cells induced a significant increase in mRNA levels of an anti-proliferative E2F member, E2F6 in this case. As was observed with E2F’s, more dramatic changes in mRNA levels of the E2F related genes cyclins and Cdks and the epithelial-mesenchymal transition (EMT) genes were observed after BTZ treatment of HepG2 compared to JHH6 . CONCLUSION The differential expression of E2Fs and related genes induced by BZB in diverse HCC cell phenotypes contribute to bortezomib’s mechanism of action in hepatocellular carcinoma.
- Published
- 2014
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