In vivo silencing of Reptin blocks the progression of human hepatocellular carcinoma in xenografts and is associated with replicative senescence

Ménard, Ludovic; Taras, Danièle; Grigoletto, Aude; Haurie, Valérie; Nicou, Alexandra; Dugot‐Senant, Nathalie; Costet, Pierre; Rousseau, Benoı̂t; Rosenbaum, Jean

doi:10.1016/j.jhep.2009.12.029

Cited by 48 publications

(57 citation statements)

References 40 publications

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“…Remarkably, Reptin silencing in vivo led to regression of hepatocellular carcinoma tumor xenografts, in association with the induction of tumor cell senescence (9). These results, which are in agreement with the reported functions of Reptin, suggest that it could be an interesting target for cancer therapy.…”

Section: Introductionsupporting

confidence: 86%

“…We have previously shown an overexpression of Reptin in hepatocellular carcinoma (8) and that Reptin silencing reduced tumor cell growth and viability in vitro (8,9), a finding confirmed by others in a number of cell lines of different origins (10)(11)(12). Remarkably, Reptin silencing in vivo led to regression of hepatocellular carcinoma tumor xenografts, in association with the induction of tumor cell senescence (9).…”

Section: Introductionsupporting

confidence: 65%

“…We previously showed that silencing of endogenous Reptin through RNA interference induced a decrease in growth of hepatocellular carcinoma cells (8,9). With the aim of determining the role of Reptin ATPase activity in hepatocellular carcinoma cell growth, we first expressed the ATPase dead mutant D299N in the presence of endogenous Reptin, using lentiviral vectors.…”

Section: Expression Of a Reptin Atpase-dead Mutant Impairs Hepatocellmentioning

confidence: 99%

“…In order to determine the effects of Reptin ATPase dead mutant in the absence of endogenous Reptin, we used a substitution strategy as previously described (9). Briefly, we previously generated a Flag-tagged Reptin cDNA harboring silent mutations that made the mRNA insensitive to the anti-Reptin siR2 siRNA.…”

Section: Expression Of a Reptin Atpase-dead Mutant Impairs Hepatocellmentioning

confidence: 99%

“…We have reported the induction of senescence following Reptin silencing in hepatocellular carcinoma cells (9). In order to test the requirement of Reptin ATPase activity for the prevention of senescence, we quantified senescenceassociated heterochromatin foci (SAHF) as a marker (21).…”

Section: Role Of Reptin Atpase Activity On Hepatocellular Carcinoma Cmentioning

confidence: 99%

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The ATPase Activity of Reptin Is Required for Its Effects on Tumor Cell Growth and Viability in Hepatocellular Carcinoma

Grigoletto

Neaud

Allain-Courtois

et al. 2013

Molecular Cancer Research

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Reptin is overexpressed in most human hepatocellular carcinomas. Reptin is involved in chromatin remodeling, transcription regulation, or supramolecular complexes assembly. Its silencing leads to growth arrest and apoptosis in cultured hepatocellular carcinoma cells and stops hepatocellular carcinoma progression in xenografts. Reptin has an ATPase activity linked to Walker A and B domains. It is unclear whether every Reptin function depends on its ATPase activity. Here, we expressed Walker B ATPase-dead mutants (D299N or E300G) in hepatocellular carcinoma cells in the presence of endogenous Reptin. Then, we silenced endogenous Reptin and substituted it with siRNA-resistant wild-type (WT) or Flag-Reptin mutants. There was a significant decrease in cell growth when expressing either mutant in the presence of endogenous Reptin, revealing a dominant negative effect of the ATPase dead mutants on hepatocellular carcinoma cell growth. Substitution of endogenous Reptin by WT Flag-Reptin rescued cell growth of HuH7. On the other hand, substitution by Flag-Reptin D299N or E300G led to cell growth arrest. Similar results were seen with Hep3B cells. Reptin silencing in HuH7 cells led to an increased apoptotic cell death, which was prevented by WT Flag-Reptin but not by the D299N mutant. These data show that Reptin functions relevant for cancer are dependent on its ATPase activity, and suggest that antagonists of Reptin

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Section: Introductionsupporting

confidence: 86%

Section: Introductionsupporting

confidence: 65%

Section: Expression Of a Reptin Atpase-dead Mutant Impairs Hepatocellmentioning

confidence: 99%

Section: Expression Of a Reptin Atpase-dead Mutant Impairs Hepatocellmentioning

confidence: 99%

Section: Role Of Reptin Atpase Activity On Hepatocellular Carcinoma Cmentioning

confidence: 99%

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The ATPase Activity of Reptin Is Required for Its Effects on Tumor Cell Growth and Viability in Hepatocellular Carcinoma

Grigoletto

Neaud

Allain-Courtois

et al. 2013

Molecular Cancer Research

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Reptin regulates insulin‐stimulated Akt phosphorylation in hepatocellular carcinoma via the regulation of SHP‐1/PTPN6

Raymond

Javary

Breig

et al. 2017

Cell Biochemistry & Function

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Hepatocellular carcinoma (HCC) is the main primary cancer of the liver. Many studies have shown that insulin resistance is a risk factor for HCC. We previously discovered the overexpression and oncogenic role of the Reptin/RUVBL2 ATPase in HCC. Here, we found that Reptin silencing enhanced insulin sensitivity in 2 HCC cell lines, as shown by a large potentiation of insulin-induced AKT phosphorylation on Ser473 and Thr308, and of downstream signalling. Reptin silencing did not affect the tyrosine phosphorylation of the insulin receptor nor of IRS1, but it enhanced the tyrosine phosphorylation of the p85 subunit of PI3K. The expression of the SHP-1/PTPN6 phosphatase, which dephosphorylates p85, was reduced after Reptin depletion. Forced expression of SHP-1 restored a normal AKT phosphorylation after insulin treatment in cells where Reptin was silenced, demonstrating that the downregulation of SHP1 is mechanistically linked to increased Akt phosphorylation. In conclusion, we have uncovered a new function for Reptin in regulating insulin signalling in HCC cells via the regulation of SHP-1 expression. We suggest that the regulation of insulin sensitivity by Reptin contributes to its oncogenic action in the liver.

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Growth arrest and DNA damage 45G down-regulation contributes to janus kinase/signal transducer and activator of transcription 3 activation and cellular senescence evasion in hepatocellular carcinoma

Zhang

Yang

et al. 2013

Hepatology

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Growth arrest and DNA damage 45G (GADD45G), a stress sensor with multiple implications in various biological processes, is down-regulated in a broad spectrum of cancers. However, little is known about the biological effects of GADD45G on hepatocellular carcinoma (HCC) cells and the related mechanisms. In the present study, we found that GADD45G was commonly down-regulated in oncogene-transformed mouse liver cells and in human and mouse HCC. Ectopic expression of GADD45G robustly elicited senescence in HCC cells and suppressed tumor growth in vivo. Furthermore, GADD45G-induced senescence occurred in HCC cells independently of p53, p16 INK4a (p16), and retinoblastoma (Rb). Instead, the prompt inhibition of Janus kinase 2 (Jak2), tyrosine kinase 2 (Tyk2), and signal transducer and activator of transcription 3 (Stat3) activation was observed in cells undergoing senescence. Impairment of Jak-Stat3 activation caused by GADD45G expression was associated with activation of SH2 domain-containing protein tyrosine phosphatase-2 (Shp2). Expression of constitutively activated Stat3 or human telomerase reverse transcriptase (hTERT), as well as knockdown of Shp2f, efficiently counteracted GADD45G-induced senescence. More important, in clinical HCC specimens, we found that GADD45G expression was inversely correlated with phosphorylated Stat3 expression in tumor cells and disease progression. Conclusion: GADD45G functions as a negative regulator of the Jak-Stat3 pathway and inhibits HCC by inducing cellular senescence. The decrease or absence of GADD45G expression may be a key event for tumor cells or premalignant liver cells to bypass cellular senescence. (HEPATOLOGY 2014;59:178-189) H epatocellular carcinoma (HCC) is one of the most malignant cancers and is listed as the second-most frequent cause of cancer deaths in men and sixth in women worldwide. 1 HCC generally develops in patients with liver cirrhosis and chronic infection with hepatitis B virus (HBV) and hepatitis C virus (HCV). Emerging evidence has shown that cellular senescence provides a tumor-suppressive mechanism for preventing liver tumorigenesis through the cell-autonomous regulation of proliferation or by triggering immune surveillance. 2-5 Consistently, genetic or functional inactivation of senescence-related proteins, such as p53 and p16/ retinoblastoma (Rb), has been observed in human HCC specimens. 6,7 Because initiation of the senescence program

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In vivo silencing of Reptin blocks the progression of human hepatocellular carcinoma in xenografts and is associated with replicative senescence

Abstract: In vivo Reptin depletion leads to tumour growth arrest. Reptin may prove a valuable target in HCC.

Cited by 48 publications

References 40 publications

The ATPase Activity of Reptin Is Required for Its Effects on Tumor Cell Growth and Viability in Hepatocellular Carcinoma

The ATPase Activity of Reptin Is Required for Its Effects on Tumor Cell Growth and Viability in Hepatocellular Carcinoma

Reptin regulates insulin‐stimulated Akt phosphorylation in hepatocellular carcinoma via the regulation of SHP‐1/PTPN6

Growth arrest and DNA damage 45G down-regulation contributes to janus kinase/signal transducer and activator of transcription 3 activation and cellular senescence evasion in hepatocellular carcinoma

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