In Vitro Effect of NDP Kinase and Its Regulation of MMP-2 Expression in A549 Lung Cancer Cell Line

Abstract

Nucleoside Diphosphate (NDP) Kinase is an enzyme that has been reported to act as an inhibitor of metastasis or transcription factor in mammals. It also functions as a differentiation-inhibiting factor in leukemic cells that is independent of NDP kinase catalytic activity and dependent on the presence of N-terminal peptide. Present study focused on in vitro effect of Streptomyces sp. NDP kinase and its regulation of Matrix metalloproteinase-2 (MMP-2) expression in A549 cell line. The purified Streptomyces sp. NDP kinase used in this study induced A549 cell death with IC50 value of 15μg/ml. Flow cytometry analysis using Annexin V and Propidium Iodide double staining, the treatment of A549 cells with 10 and 20μg/ml of Streptomyces sp. NDP kinase for 24 h respectively, showed 26.96% and 47.61% of cells undergoing apoptosis respectively, while the percentage of necrotic cells appeared 13.11% in both concentrations. As NDP kinase from human is a potent metastatic suppressor, the effect of Streptomyces sp.-strained NDP kinase on gene expression of MMP-2, which is involved in the induction of cancer metastasis, was studied using real time PCR. NDP kinase significantly down regulates MMP-2 gene expression in concentrationdependent manner. This is the first report of NDP kinase from naturally isolated Streptomyces sp. that regulates MMP-2 gene expression.