DNA Methyltransferases 1 and 3b Expression in Huh-7 Cells Expressing HCV Core Protein of Different Genotypes
- 324 Downloads
Hepatitis C virus infects ~3 % of the population and it is a risk factor for hepatocarcinogenesis. The epigenetic mechanisms of HCV-induced hepatocyte transformation towards malignancy in this context are unclear.
The purpose of this study was to evaluate the effect of HCV core proteins of different genotypes on DNA methyltransferases (DNMTs) induction.
We investigated DNMT1, DNMT3b and E-Cadherin (CDH1) mRNA and protein expression levels in an in vitro model of Huh-7 cells expressing the HCV core protein of different genotypes: 1b, 2a, 3a, 4h and 5a.
We found that both mRNA and protein expression levels of DNMT1 and 3b were upregulated in genotype 1b HCV core expressing cells as compared to control cells. DNMT3b mRNA levels did not change in genotypes 2a, 3a, 4h and 5a, but were upregulated at the protein level by genotype 1b, 2a, 3a. CDH1 mRNA expression was downregulated only in genotype 1b, whereas its protein expression resulted in downregulation by the HCV core of genotypes 1b, 2a and 3a. Conversely, no significant changes were observed for DNMTs and CDH1 investigated in Huh-7 cells expressing the genotypes 4h and 5a. Furthermore, we present evidence that HCV core 1b protein expression induces DNMTs overexpression through STAT3 protein as demonstrated by NSC74859 treatment. Moreover, SIRT1 inhibition affected DNMT1 and 3b expression only in HCV core protein genotype 1b expressing cells as demonstrated by treatment with its inhibitor sirtinol.
Our findings suggest that HCV core protein could play a role in HCC development at least in part by altering DNMTs expression.
KeywordsHCV core DNMTs CDH1 STAT3 SIRT1
We thank Prof. Francesco Negro in whose laboratory the plasmids pIRES2-EGFP/Core of different genotypes were generated. This work was supported by the “Italian Ministry of Health” from grant RC1103GA48, through the Research Unit of Gastroenterology, “Casa Sollievo della Sofferenza” IRCCS, San Giovanni Rotondo (FG), Italy.
Conflict of interest
No conflict of interest is declared.
- 13.Ripoli M, Barbano R, BalsamoT, Piccoli C, Brunetti V, Coco M, Mazzoccoli G, Vinciguerra M, Pazienza V. Hypermethylated levels of E-cadherin promoter in Huh-7 cells expressing the HCV core protein. Virus Res. 2011;160:74–81.Google Scholar
- 16.Brooks CL, Gu W. How does SIRT1 affect metabolism, senescence and cancer? Nat Rev Cancer. 2009;9:123–128.Google Scholar
- 19.Dejeux E, Audard V, Cavard C, Gut IG, Terris B, Tost J. Rapid identification of promoter hypermethylation in hepatocellular carcinoma by pyrosequencing of etiologically homogeneous sample pools. J Mol Diagn. 2007;9:510–520.Google Scholar
- 21.Chen J, Zhang B, Wong N, Lo AW, To KF, Chan AW, Ng MH, Ho CY, Cheng SH, Lai PB, Yu J, Ng HK, Ling MT, Huang AL, Cai XF, Ko BC. Sirtuin 1 is upregulated in a subset of hepatocellular carcinomas where it is essential for telomere maintenance and tumor cell growth. Cancer Res. 2011;71:4138–149.Google Scholar
- 25.Vivekanandan P, Daniel HD, Kannangai R, Martinez-Murillo F, Torbenson M. Hepatitis B virus replication induces methylation of both host and viral DNA. J Virol. 2010;84:4321–4329.Google Scholar
- 32.Paredes R, Esteller M. Cancer epigenetics reaches mainstream oncology. Nature Med. 2011;17:330–339.Google Scholar
- 34.Nie Y, Erion DM, Yuan Z, Dietrich M, Shulman GI, Horvath TL, Gao Q. STAT3 inhibition of gluconeogenesis is downregulated by SirT1. Nat Cell Biol. 2009;11:492–500.Google Scholar
- 35.Bernier M, Paul RK, Martin-Montalvo A, Scheibye-Knudsen M, Song S, He HJ, Armour SM, Hubbard BP, Bohr VA, Wang L, Zong Y, Sinclair DA, de Cabo R. Negative regulation of STAT3 protein-mediated cellular respiration by SIRT1 protein. J Biol Chem. 2011;286:19270–19279.Google Scholar