Overexpression and role of the ATPase and putative DNA helicase RuvB-like 2 in human hepatocellular carcinoma

TitreOverexpression and role of the ATPase and putative DNA helicase RuvB-like 2 in human hepatocellular carcinoma
Publication TypeJournal Article
Year of Publication2007
AuthorsRousseau B, Menard L, Haurie V, Taras D, Blanc JF, Moreau-Gaudry F, Metzler P, Hugues M, Boyault S, Lemiere S, Canron X, Costet P, Cole M, Balabaud C, Bioulac-Sage P, Zucman-Rossi J, Rosenbaum J
JournalHepatology
Volume46
Issue4
Pagination1108-18
Mots-clés80 and over Animals Apoptosis/genetics/physiology Carcinoma, Adenosine Triphosphatases/genetics/*metabolism Aged Aged, Hepatocellular/etiology/*metabolism/pathology Carrier Proteins/genetics/*metabolism Caspase 3/genetics/metabolism Cell Line, Heterologous, Inbred Strains Middle Aged RNA, Messenger/genetics/metabolism Transplantation, Neoplastic Humans Liver Neoplasms/etiology/*metabolism/pathology Male Mice Mice, Tumor Cell Proliferation DNA Fragmentation DNA Helicases/genetics/*metabolism Female Gene Expression Regulation
AbstractUsing a proteomic analysis of human hepatocellular carcinoma (HCC), we identified the overexpression in 4 tumors of RuvB-like 2 (RUVBL2), an ATPase and putative DNA helicase known to interact with beta-catenin and cellular v-myc myelocytomatosis viral oncogene homolog (c-myc). RUVBL2 expression was further analyzed in tumors with quantitative reverse-transcription polymerase chain reaction analysis and immunohistochemistry; in addition, RUVBL2 expression in a HuH7 cell line was silenced by small interfering RNA or increased with a lentiviral vector. RUVBL2 messenger RNA overexpression was confirmed in 72 of 96 HCC cases, and it was associated with poorly differentiated tumors (P = 0.02) and a poor prognosis (P = 0.02) but not with beta-catenin mutations or c-myc levels. Although RUVBL2 was strictly nuclear in normal hepatocytes, tumoral hepatocytes exhibited additional cytoplasmic staining. There was no mutation in the coding sequence of RUVBL2 in 10 sequenced cases. Silencing RUVBL2 in HuH7 HCC cells reduced cell growth (P < 0.001) and increased apoptosis, as shown by DNA fragmentation (P < 0.001) and caspase 3 activity (P < 0.005). This was associated with an increased expression of several proapoptotic genes and with an increased conformational activation of Bak-1 and Bax. On the other hand, HuH7 cells with an overexpression of RUVBL2 grew better in soft agar (P < 0.03), had increased resistance to C2 ceramide-induced apoptosis (P < 0.001), and gave rise to significantly larger tumors when injected into immunodeficient Rag2/gammac mice (P = 0.016). CONCLUSION: RUVBL2 is overexpressed in a large majority of HCCs. RUVBL2 overexpression enhances tumorigenicity, and RUVBL2 is required for tumor cell viability. These results argue for a major role of RUVBL2 in liver carcinogenesis.
URLhttp://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&dopt=Citation&list_uids=17657734
DOI10.1002/hep.21770
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