[Inhibitory effect of lentiviral vector-mediated SHIP gene transfection on proliferation of leukemia K562 cells and PI3K/Akt pathway regulation].

Background and Objective: The hemopoietic-restricted Src homology 2-containing inositol 5'-phosphatase (SHIP) acts as a negative regulator for the proliferation and survival of hematopoietic cells by hydrolysing the phosphoinositide 3-kinase (PI3K)-generated second messenger, PtdIns(3,4,5)-P3 (PI-3,4,5-P3) to PtdIns(3,4)-P2 (PI-3,4-P2). This study was to investigate the biological function of SHIP gene in pathogenesis of leukemia cells by lentiviral vector-mediated SHIP transfection.
Methods: Ectopic SHIP gene was transfected into leukemia K562 cells by the mediation of lentiviral vector. The mRNA level of SHIP was detected by fluorescent quantitative reverse transcription-polymerase chain reaction (FQ-PCR). The expression of SHIP, Akt, and phosphorylated Akt (p-Akt) was detected by Western blot. The proliferation and morphology of K562 cells before and after SHIP gene transfection were compared.
Results: The proliferation of K562 cells was inhibited after transfection: the proliferation inhibition rate was increased from (9.9+/-1.5)% on Day 3 to (40.6+/-2.3)% on Day 5. K562 cells were SHIP-negative but expressed high level of p-Akt which was down-regulated from 0.533 to 0.245 (P<0.01) after SHIP transfection. Apoptotic characteristics were showed in K562 cells after SHIP transfection. The early apoptosis rate was significantly higher in K562-wtSHIP-FIV-G cells than in K562-FIV-G cells and untransfected K562 cells [(38.3+/-4.3)% vs. (8.2+/-0.9)% and (7.7+/-0.8)%, P<0.05].
Conclusions: SHIP gene can inhibit cell proliferation and promote cell apoptosis via inactivating PI3K/Akt pathway. Loss of SHIP might activate PI3K/Akt pathway and promote the proliferation of K562 cells.