OBJECTIVETo explore the effect of mutation in PxxP domain of SHIP on migration and invasion of leukemia cells and its mechanism.

METHODSThe lentiviral vector mediated wild type SHIP (wtSHIP) and mutant SHIP (muSHIP) plasmids were transfected into K562 cells through gene transfection techniques. Expression of SHIP at mRNA and protein level was detected by real-time PCR and Western blot, respectively. Transwell assay was used to analyze the difference between the migration and invasion ability of the K562/wtSHIP and the K562/muSHIP cells after transfection. Primary migration associated factor FAK, MMP and NF-κB were assayed by Western blot.

RESULTSAfter transfection, the SHIP expression in transfected K562 cells were significantly increased. Compared with the migration ability of K562/wtSHIP\[(15.8 ± 1.4)%\], that of K562/muSHIP cells \[(54.3 ± 2.4)% \] increased greatly and almost at the same level of that of K562/pFIV\[(50.3 ± 3.8)%\] (P < 0.01). The invasion assay also showed that K562/wtSHIP\[(32 ± 6)/HP\] has a lower invasion ability than that of the K562/muSHIP group \[(83 ± 16)/HP\] and K562/pFIV group \[(78 ± 13)/HP\] (P < 0.01). Western blot analysis showed that the expression of p-FAK and NF-κB was up-regulated in K562/muSHIP group compared to that of the K562/wtSHIP group.

CONCLUSIONSThe results confirmed that mutation in PxxP domain of SHIP gene played an important role in negative regulating function of SHIP gene. The mutation affects the cell migration and invasion ability through increase in MMP-9 expression, FAK phosphorylation and NF-κB activation. It suggested that the mutation of PxxP domain in SHIP gene might be pathogenic, and be one of the reasons for SHIP abnormality in leukemia.