The expression and mechanism of PTEN and COX-2 in myeloid leukemia cells

Objective To investigate expression and regulatory mechanism of phosphatase and tensin hemology deleted on chromosome ten gene (PTEN) and cyclooxygenase-2 (COX-2) in human myeloid leukemia cells. Methods Thirty patients was collected from the First Hospital of Baoding and Second Affiliated Hospital of Hebei Medical University, including 10 chroni myeloid leukemiac （CML） patients in chronic phase (CML-CP), 10 CML patients in blast crises (CML-BC) and 10 normal controls.The recombinated adenovirus containing green fluorescent protein (GFP) and PTEN（Ad-PTEN-GFP）or empty vector （Ad-GFP）was transfected into human CML K562 cells.The growth of K562 cells and cell adhesion ability was observed by 3-［4,5-dimethyl-2-thiazolyl］-2,5-dip （MTT） assay; PTEN and COX-2 messenger ribonucleic acid （mRNA） levels were detected by real-time fluorescent relative-quantification reverse transcriptional PCR (FQ-PCR).PTEN and p-Akt protein levels were detected by western blot,and COX-2 protein were measured with cytochemical staining. Results The mRNA expression levels of PTEN in CML-BC patients （0.022±0.021） were lower than CML-CP patients （1.134±1.124） and normal control（1.059±0.595）.The mRNA expression levels of COX-2 in CML-BC patients （0.761±0.418） were higher than CML-CP （0.211±0.158） and normal control （0.165±0.152）.The growth of K562 cells was suppressed markedly, and the maximum growth inhibition rate was 38.67%±4.30% after transfected with PTEN gene, which was higher than Ad-GFP group （5.34%±0.31%, t=13.39，P<0.01）.COX-2 mRNA expression levels in Ad-PTEN-GFP（0.013±0.001）were significantly lower than Ad-GFP group（0.199±0.018）and untransfected group （0.217±0.021, F=499.45， P<0.01）, and p-Akt as well as COX-2 protein were also down-regulated after K562 cells transfected (MOI=200) with wild type PTEN in three days. Conclusion PTEN may inhibit proliferation and adhesion ability of leukemia cell in myeloid leukemia via down-regulating COX-2 expression. （Chin J Lab Med,2012,35:165-169） Key words: Leukemia，myeloid，accelerated phase; PTEN phosphohydrolase; Cyclooxygenase 2