[Effect of a methylation inhibitor 5-aza-2'-deoxycytidine on SHP-1 gene expression, proliferation and apoptosis in K562 cells].

Abstract

The aim of this study was to investigate the regulation of 5-aza-CdR on transcription of SHP-1 gene and effects on the proliferation and apoptosis of K562 cells. Methylation-specific PCR (MSP) was used to detect CpG island methylation in SHP-1 promoter. MTT and flow cytometry were used to detect the growth and apoptosis of K562 cells after treatment with different concentration of 5-aza-CdR. The expressions of SHP-1 mRNA and protein were determined by FQ-PCR and Western blot. The expression of p-JAK2 was assayed by Western blot. The result showed that methylation of SHP-1 gene promoter was detected in K562 cells, and the SHP-1 mRNA and protein were expressed again in K562 cells after treatment with 5-aza-CdR, meanwhile the expression of phosphorylated P-JAK2 was down-regulated; 5-aza-CdR significantly inhibited the cell growth in dose and time dependent manners. AG490 inhibited the cell proliferation. 5-aza-CdR increased the apoptosis rate of K562 cells also in dose- and time-dependent manners. The apoptosis rates of K562 cells treated with 5-aza-CdR for 1, 3 and 5 days were 9.3%, 24.2% and 37.7% respectively. After treatment with 2 micromol/L 5-aza-CdR for 24 hours, cells in G(0)/G(1) phase increased gradually, cells in G(2)/M phase decreased gradually, cells were arrested in G(0)/G(1) phase. The cell ratios in G(2)/M phase at 1, 3 and 5 days after treatment with 5-aza-CdR were 30.7%, 23.45 and 19.3% respectively. It is concluded that the 5-aza-CdR, inhibitor of specific methylation transferase, can re-express the silent SHP-1 gene in K562 cells, inhibits the proliferation of leukemia cells and induces cell apoptosis by activating JAK/STAT pathway.

• Authors: Jian-Min Luo, Yan Li, Lin Yang, Xiao-Jun Liu, Shu-Peng Wen, Fu-Xu Wang, Jing-Yu Zhang, Xue-Jun Zhang, Zuo-Ren Dong
• Journal: Zhongguo shi yan xue ye xue za zhi (Zhongguo Shi Yan Xue Ye Xue Za Zhi) Vol. 17 Issue 2 Pg. 309-14 (Apr 2009) ISSN: 1009-2137 [Print] China
• PMID: 19379557 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Decitabine
• PTPN6 protein, human
• Protein Tyrosine Phosphatase, Non-Receptor Type 6
• Azacitidine

Topics

• Apoptosis (drug effects)
• Azacitidine (analogs & derivatives, pharmacology)
• Cell Proliferation (drug effects)
• DNA Methylation (drug effects)
• Decitabine
• Gene Expression Regulation, Leukemic (drug effects)
• Humans
• K562 Cells
• Protein Tyrosine Phosphatase, Non-Receptor Type 6 (genetics, metabolism)