title: PML(NLS(-)) inhibits cell apoptosis and promotes proliferation in HL-60 cells.
abstract: Promyelocytic leukemia (PML) is a cell-growth suppressor, and PML-retinoic acid receptor α (PML-RARα) is known as a fusion gene of acute promyelocytic leukemia (APL). Studies have reported that neutrophil elastase(NE) cleaved bcr-1-derived PML-RARα in early myeloid cells leading to the removal of nuclear localization signal (NLS) from PML. The resultant PML without NLS named PML(NLS(-)). PML(NLS(-)) mainly locates and functions in the cytoplasm. PML(NLS(-)) may act in different ways from PML, but its biological characteristics have not been reported. In this study, the PML (NLS(-)) was silenced with shRNA [HL-60/pPML(NLS(-))-shRNA] and over-expressed by preparation of recombinant adenovirus [HL-60/pAd-PML(NLS(-))]. The mRNA and protein expression of PML(NLS(-)) were detected by RT-PCR and Western blot respectively. Cell proliferation in vitro was assessed by MTT assay. Flow cytometry (FCM) was used to detect apoptotic cells. The transcription of BCL-2, BAX and C-MYC was detected in HL-60/pAd-PML(NLS(-)) cells. Our results showed that compared to the control group, the expression of PML(NLS(-)) was significantly reduced in the HL-60/pPML(NLS(-))-shRNA cells, and increased significantly in the HL-60/pAd-PML(NLS(-)) cells. The proliferation was significantly inhibited in the HL-60/pPML(NLS(-))-shRNA cells in a time-dependent manner, but markedly promoted in the HL-60/pAd-PML(NLS(-)) cells treated with 60 μmol/L emodin. FCM revealed the apoptosis increased in HL-60/pPML(NLS(-))-shRNA cells, and decreased in the HL-60/pAd-PML(NLS(-)) cells. The expression of BAX decreased significantly, while that of BCL-2 and C-MYC increased significantly in HL-60/ pAd-PML(NLS(-)) cells. Down-regulation of PML(NLS(-)) expression inhibits the proliferation and induces the apoptosis of HL-60 cells. On the contrary, over-expression of PML(NLS(-)) promotes the proliferation and reduce the emodin-induced apoptosis of HL-60 cells.
authors.affiliation: Central Laboratory of Yong-chuan hospital, Chongqing Medical University, Chongqing 402160, China.
authors.forename: Yuan-Mei
authors.initials: YM
authors.lastname: Gao
authors.forename: Liang
authors.initials: L
authors.lastname: Zhong
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.forename: Xiu-Xiu
authors.initials: XX
authors.lastname: Hu
authors.forename: Bei-Zhong
authors.initials: BZ
authors.lastname: Liu
mesh_terms: D017209:Apoptosis / Q000235:genetics*; D049109:Cell Proliferation; D015536:Down-Regulation; D015973:Gene Expression Regulation, Leukemic; D018922:HL-60 Cells; D006801:Humans; D015473:Leukemia, Promyelocytic, Acute / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000096:biosynthesis / Q000235:genetics; D019913:Nuclear Localization Signals / Q000378:metabolism; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D034741:RNA, Small Interfering
chemical_list: D009363:Neoplasm Proteins; D019913:Nuclear Localization Signals; D015514:Oncogene Proteins, Fusion; D034741:RNA, Small Interfering; C093476:promyelocytic leukemia-retinoic acid receptor alpha fusion oncoprotein
keywords: PML(NLS-); apoptosis.; over-expression; proliferation; shRNA