Background: GNMT (glycine N-methyltransferase) is a tumor suppressor gene, but the mechanisms mediating its suppressive activity are not entirely known. Methods: We investigated the oncosuppressive mechanisms of GNMT in human hepatocellular carcinoma (HCC). GNMT mRNA and protein levels were evaluated by quantitative RT-PCR and immunoblotting. GNMT effect in HCC cell lines was modulated through GNMT cDNA induced overexpression or anti-GNMT siRNA transfection. Results: GNMT was expressed at low level in human HCCs with a better prognosis (HCCB) while it was almost absent in fast-growing tumors (HCCP). In HCCB, the nuclear localization of the GNMT protein was much more pronounced than in HCCP. In Huh7 and HepG2 cell lines, GNMT forced expression inhibited the proliferation and promoted apoptosis. At the molecular level, GNMT overexpression inhibited the expression of CYP1A (Cytochrome p450, aromatic compound-inducible), PREX2 (Phosphatidylinositol-3,4,5-trisphosphate-dependent Rac exchange factor 2), PARP1 [Poly (ADP-ribose) polymerase 1], and NFKB (nuclear factor-kB) genes. By chromatin immunoprecipitation, we found GNMT binding to the promoters of CYP1A1, PREX2, PARP1, and NFKB genes resulting in their strong inhibition. These genes are implicated in hepatocarcinogenesis, and are involved in the GNMT oncosuppressive action. Conclusion: Overall, the present data indicate that GNMT exerts a multifaceted suppressive action by interacting with various cancer-related genes and inhibiting their expression.

Nuclear localization dictates hepatocarcinogenesis suppression by glycine N-methyltransferase / Simile, M. M.; Cigliano, A.; Paliogiannis, P.; Daino, L.; Manetti, R.; Feo, C. F.; Calvisi, D. F.; Feo, F.; Pascale, R. M.. - In: TRANSLATIONAL ONCOLOGY. - ISSN 1936-5233. - 15:1(2021), p. 101239. [10.1016/j.tranon.2021.101239]

Nuclear localization dictates hepatocarcinogenesis suppression by glycine N-methyltransferase

Simile M. M.;Cigliano A.;Paliogiannis P.;Daino L.;Manetti R.;Feo C. F.;Calvisi D. F.;Feo F.;Pascale R. M.
2021-01-01

Abstract

Background: GNMT (glycine N-methyltransferase) is a tumor suppressor gene, but the mechanisms mediating its suppressive activity are not entirely known. Methods: We investigated the oncosuppressive mechanisms of GNMT in human hepatocellular carcinoma (HCC). GNMT mRNA and protein levels were evaluated by quantitative RT-PCR and immunoblotting. GNMT effect in HCC cell lines was modulated through GNMT cDNA induced overexpression or anti-GNMT siRNA transfection. Results: GNMT was expressed at low level in human HCCs with a better prognosis (HCCB) while it was almost absent in fast-growing tumors (HCCP). In HCCB, the nuclear localization of the GNMT protein was much more pronounced than in HCCP. In Huh7 and HepG2 cell lines, GNMT forced expression inhibited the proliferation and promoted apoptosis. At the molecular level, GNMT overexpression inhibited the expression of CYP1A (Cytochrome p450, aromatic compound-inducible), PREX2 (Phosphatidylinositol-3,4,5-trisphosphate-dependent Rac exchange factor 2), PARP1 [Poly (ADP-ribose) polymerase 1], and NFKB (nuclear factor-kB) genes. By chromatin immunoprecipitation, we found GNMT binding to the promoters of CYP1A1, PREX2, PARP1, and NFKB genes resulting in their strong inhibition. These genes are implicated in hepatocarcinogenesis, and are involved in the GNMT oncosuppressive action. Conclusion: Overall, the present data indicate that GNMT exerts a multifaceted suppressive action by interacting with various cancer-related genes and inhibiting their expression.
2021
Nuclear localization dictates hepatocarcinogenesis suppression by glycine N-methyltransferase / Simile, M. M.; Cigliano, A.; Paliogiannis, P.; Daino, L.; Manetti, R.; Feo, C. F.; Calvisi, D. F.; Feo, F.; Pascale, R. M.. - In: TRANSLATIONAL ONCOLOGY. - ISSN 1936-5233. - 15:1(2021), p. 101239. [10.1016/j.tranon.2021.101239]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11388/249638
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