Molecular mechanisms of absent in melanoma AIM2 inducing breast cancer cell apoptosis / 医学研究生学报

ABSTRACT

Objective The human IFN-inducible protein absent in melanoma 2 (AIM2) has been regarded as a tumour sup-pressor, however, the molecular mechanisms of its antitumor activity still remain unclear.This research is to study the molecular mech-anisms of AIM2 inducing breast cancer cell apoptosis. Methods Tet-Off induction model system was established to induce AIM2 ex-pression in great quantities, MCF-7 tTA-AIM2 cells as the experimental group and MCF-7 tTA-Luc cells as control group.Western blotting was used to detect AIM2 expression in breast cancer cell lines and subcellular localization.XTT assay was applied to analyze the effects of AIM2 on cell proliferation.Apoptosis were detected by Annexin V-FITC and propidium iodide staining, and the apoptosis mechanism were investigated by west blot. Results The established Tet-off guidance system could combine tTA to TRE, thereby promoting AIM2 gene transcription and inducing great expression of AIM2 protein.4 days after induction, the expression of AIM2 could be detected in cytoplasm and nucleus, and AIM2 expression increased with the increasing days.XTT assay detected the growth speed of MCF-7 tTA-AIM2 cell lines slowed down 6 days after induction.After abundant expression of induced AIM2, the percentage of FITC fluorescence apoptosis increased significantly (2.36%vs 14.45%, P<0.01) .Increased AIM2 expression inhibited the expression of the anti-apoptotic protein Bcl-xL, increased the expression of the apoptosis proteins Bad and Bax, and activated caspases, resulting in the cleavage of DNA repair protein PARP. Conclusion In breast cancer Tet-off induction system, AIM2 will express in cytoplasm and nucleus, influence cell proliferation, and stimulate the mitochondria to cell apoptosis.