Effect On SHIP-2 Gene Of Gleevec In K562 Cells And It's Significance

Objective:CML as a common clinical myeloproliferative disorders, t (9; 22) chromosomal ectopic exists in Cloning of the disease, which form the bcr/abl fusion gene, it encods P210 that is a kind of strong tyrosine kinases, the emergence of the proteins is an important pathogenesis basis of CML. Study shows that PI3K pathway is important in bcr/abl downstream. Phosphatidylinositol kinase(PI3K) received growth signals and then activated and generated PIP3, which as a second messenger to activate downstream signaling molecules Akt / PKB, so that to maintain cell survival and against apoptosis caused by a variety of factors . At present, many studies have focused on the relevance of phosphoinositide-mediated signaling pathway and apoptosis . PI3K and AKt/PKB are serine / threonine kinase , A large number of studies have proved that PI3K and AKt/PKB are cancer genes. Akt/PKB can catalyze BDA and Caspase-1, caspase-3 phosphorylation directly so that to make them inactivate. And inhibit them to promote apoptosis , Inositol lipid phosphatase (PIPase) are tumor suppressor genes. SHIP(SH2 domain containing inositol 5'-phosphatase) is a members of PIPase, it belongs to inositol 5 'phosphatase family,and mainly expresses in hematopoietic cells and play a key role in negative regulation to the occurrence and development of hematopoietic cells and their functions. Studies have shown that in hematopoietic cell, SHIP inhibit the function of Akt.SHIP can specificly remove phosphatidyl- inositol triphosphate (PIP3), and PI (3, 4, 5) P3 which as a second messenger and plays an important function in the survival of the process within cells. In the marrow of SHIP-/- mouse ,it Shows chronic eosinophil and macrophage proliferation, while Akt phosphorylation levels increase with time goes on, And because of bone marrow cells infiltrate to importent organes, they showed myeloproliferative disorders and the survival time shorten .In chronic myeloid leukemia cells,Because of the existence of bcr / abl gene ,the expression of SHIP reduct and shows the granulocyte cells increase extremely and resistance to chemotherapy. These studies strongly suggest that in hematopoietic cells, SHIP gene may plays as a tumor suppressor gene.Other studies have shown that in CML patients,the SHIP gene expression levels significantly reduced even absent. because bcr / abl directly inhibit the expression of SHIP gene, after applicate the abl specific inhibitor STI571 , SHIP gene expression recovery,that suggesting that phosphatidylinositol pathway has played a key role in the pathogenesis of CML . Newly discovered SHIP-2 gene is homology with ship-1,and it also belongs to 5'-phosphatase family. Its expression is more extensive, not only expressed in hematopoietic cells, but also expressed in tissue cells. It is worth mentioning that, SHIP-2 can be directly connected to the SH3 regional role of abl, Compared to SHIP-1 ,which connect with abl indirectly ,SHIP-2 may also play a role in the occurrence and development of CML.This experiment is to observe the expression of SHIP-2 gene and bcr/abl fusion gene and the phosphorylation level of AKt in K562 cells after the intervention of Gleevec.Explore the role of SHIP-2 gene in the occurrence and development of CML and it's significance.Methods:Treat K562 cells with different concentrations of Gleevec,Collect the cells at different times,use real-time quantitative to detect the mRNA expression levels of SHIP-2, bcr / abl fusion gene within trail groups and control groups .K562 cells were cultured in RPMI 1640 and take the cells which in logarithmic phase , detect the effct on the Proliferation of K562 cells of SHIP-2 expression changes with MTT method , detect the phosphorylation levels of AKt within K562 cells within different times after same concentration Gleevec treatmen with Western blot method .Results: 1 The same time point , in K562 cells , bcr / abl fusion gene expression levels decreased as the drug concentration gradually increase.intervent K562cells with the same drug concentration , bcr / abl fusion gene expression levels decreased with the time extend.2 SHIP-2 gene expression levels increase as the bcr/abl gene expression levels decreased .3 The phosphorylation levels of AKt decreased as the SHIP-2 gene expression level increase.simultaneously , the proliferation of K562 cells inhibited.Conclusions:In K562 cells ,the expression of bcr/abl was bloked by gleevec,then the expression of SHIP-2 gene increased;the phosphorylation levels of AKt decreased ;the proliferation of K562 cells were inhibited,SHIP-2 gene may play a negative role in the development of leukemia .