Down-regulated expression and antioncogenetic role of GADD45g in acute myeloid leukemia / 中国肿瘤生物治疗杂志

ABSTRACT

@#[Abstract] Objective: To quantify the expression of growth arrest and DNA damage inducible protein 45g (GADD45g) gene in the bone marrow samples of patients withAML (acute myeloid leukemia) and inAML cell lines, as well as to study the correlation between the GADD45g expression and prognostic outcome in patients withAML and investigate the role of GADD45g over-expression in proliferation, apoptosis, senescence, differentiation, cell cycle arrest, and drug sensitivity in AML cell lines. Methods: In the study, a total of 27 cases of bone marrow specimens were selected from patients initially diagnosed as AML in Hospital of Blood Diseases affiliated to Chinese Academy of Medical Sciences from January 2013 to December 2016. mRNA and protein expression levels of GADD45g in BMMNCs (Bone marrow mononuclear cells) from patients with AML and healthy donors and in AML cell lines were quantified by quantitative real-time PCR and Western blotting. The correlation between GADD45g expression and overall survival (OS), coupled with event-free survival (EFS) in patients with AML was analyzed in two gene expression datasets (GSE10358, GSE425-GPL317). Lentiviral vectors over-expressing GADD45g were constructed and transfected into AML cell lines (U937, THP-1 and Molm-13 cell lines). The role of GADD45g over-expression in cell proliferation, colony formation, senescence, apoptosis, cell cycle arrest, differentiation and drug sensitivity of U937, THP-1 and Molm-13 cells were detected by cell counting, colony-forming assay, β-galactosidase staining and flow cytometric analysis of Annexin V/7AAD staining, PI staining and so on, respectively. Results: Expression of GADD45g was dramatically down-regulated in BMMNCs in AML patients and AML cell lines compared to that from healthy donors (all P<0.01). The OS (P<0.05) and EFS (P<0.05) of AML patients with low GADD45g expression were significantly shorter that those of AML patients with higher GADD45g level. Enforced expression of GADD45g could inhibit cell growth and colony formation, promote senescence and apoptosis, induce cell cycle arrest and differentiation and enhance drug sensitivity in AML cell lines (P<0.05 or P<0.01). Conclusion: GADD45g expression was remarkably silenced in marrow tissues of patients withAML andAML cell lines; it showed remarkable and all-around inhibiting effect onAMLcell lines, indicating that GADD45g expression has prognostic value inAML.