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[The mechanism for SHIP gene to induce the apoptosis of human leukemia cell line K562.] [Ariticle in Chinese]

Yang Lin, LUO Jian-Min^*, LIU Xiao-Jun, WEN Shu-Peng, DU Xing-Yan, YAO Li, YANG Jing-Ci

Province Key Laboratory of Hematology, Department of Hematology, the Second Hospital of Hebei Medical University, Shijiazhuang 050000, China

Abstract

The src homology 2 (SH2)-domain containing inositol-5-phosphatase (SHIP) is another recently identified lipid phosphatase after phosphatase and tensin homology deleted on chromosome ten gene (PTEN). It plays an important role in negatively regulating the proliferation of hematopoietic cells. The relationship between SHIP and the inhibition of tumor proliferation is rarely reported. The purpose of this study is to evaluate the apoptosis induced by SHIP gene in K562 cell line and to explore the involved signaling pathway. The K562 cells were transfected with human SHIP gene by using the lentiviral vector containing SHIP, and the transfection was verified by fluorescent quantitative PCR (FQ-PCR) and Western blot. Then the effects of SHIP protein expression on cell growth and apoptosis were measured. The levels of p-Akt, bcl-2 family, caspase and the activity of NFκB were assayed by Western blot and ELISA, respectively. The results are as follows: (1) Human leukemia cell line K562 was SHIP-negative; (2) Transfection with SHIP gene led to the re-expression of SHIP mRNA and protein in K562, as shown by FQ-PCR and Western blot; (3) The expression of SHIP protein inhibited cell growth and significantly increased apoptosis in K562 cells; (4) Compared to that in control group, the expression level of p-Akt-308 and p-Akt-473 in SHIP-expressing cell group decreased significantly (P<0.01); SHIP activated caspase-9, caspase-3, up-regulated protein levels of bad, p27, down-regulated expression of bcl-xL, while it had no effect on the expression of bcl-2 and bax. Furthermore, the inhibition of NF-κB was achieved along with the inactivation of Akt. These data suggest that SHIP gene has potential abilities to inhibit K562 leukemic cell proliferation and induce its apoptosis via inactivating PI3K/Akt pathway. The loss of SHIP might be the explanation of aberrant high-level p-Akt in human leukemia. It may be at least one of the mechanisms by which the loss of SHIP expression contributes to leukemia progression.

Key words: gene, SHIP; lentivirus expression system; cell proliferation; cell apoptosis

Received: 2008-08-18　　Accepted: 2009-01-12

Corresponding author: 罗建民　　E-mail: luojm315@yahoo.com.cn

Citing This Article：

Yang Lin, LUO Jian-Min, LIU Xiao-Jun, WEN Shu-Peng, DU Xing-Yan, YAO Li, YANG Jing-Ci. [The mechanism for SHIP gene to induce the apoptosis of human leukemia cell line K562.] [Ariticle in Chinese] . Acta Physiol Sin 2009; 61 (2): 146-154 (in Chinese with English abstract).