Study Of Bortezomib Enhance The Cytotoxicity Of CIK On K562and K562/ADR Cells

Objective:Chemotherapy has been the standard of care for the patients with acute leukemia. However, due to its side effects, the therapeutic success of chemotherapy has always been limited. Leukemia relapse after treatment and produce the multiple drug resistance of tumor cells is the difficult of treatment. With the deepening of the pathogenesis of leukemia immune,it has become a very important means of leukemia especially clear minimal residual disease. CIK cells are generated from peripheral blood mononuclear cells which are activated by a variety of cytokines, and monoclonal antibodyin vitro. It also has the T lymphocytes strong anti-tumor activity and Natural killer cells main organizational features of MHC restriction tumoricidal. It can play the anti-tumor activity by identified expression of NKG2D ligands in tumor cell surface. NKG2D is an activating receptor of natural killer cells, with ligand cross-linking can activate the cytotoxic activity of effector cells. But studies have shown that, most of the leukemia cells do not express or low expression of NKG2D ligands.To find the drugs raised NKG2D ligand expression is one of the ways to improve the efficacy of immunotherapy.Bortezomib is a novel anti-tumor targeted therapy drug, mainly used for the treatment of relapsed or refractory multiple myeloma, and has shown good results. In vitro studies, Bortezomib had shown a good effect on a variety of malignant tumor cells,but there is few report in leukemia. These study investigated that if Bortezomib could increase the expression of MICA in K562、K562/ADR cells,enhance the cytotoxicity of CIK cell and increase the rate of apoptosis of tumor cells,to find new targets immunotherapy of leukemia.Methods:1. Bortezomib incubated with the K562and K562/ADR cells, after48hours, The difference of the genes expression of MICA (MICAmRNA) was determined by RT-PCR before and after treating with Bortezomib.2.The cytotoxic sensitivity of the K562and K562/ADR cells to CIK cells before and after treating with Bortezomib was measured by MTT.3. Annexin v/PI method to detect the cell apoptosis rate.Results:l.The MICA mRNA of K562cells after treating with Bortezomib is (3.22±0.42)times than that of before; MICA mRNA of K562ADR cells after treating with Bortezomib is(2.88±0.76)times than that of before (P<0.05).2.The cytotoxic sensitivity of K562cells and K562/ADR cells to CIK cells increased by treating with Bortezomib, and the cytotoxic sensitivity was higher than un-tread cells, at the E:T ratio of10:1and20:1,the difference have statistical significance (P<0.05).3. K562cells and K562/ADR cells to CIK cells by treating with Bortezomib apoptosis rate exist significant difference, statistically significant.Conclusion:1.The different expression of MICAmRNA on the surface of K562and K562/ADR cells was significantly.2.The MICAmRNA of K562and K562/ADR cells after treating with Bortezomib have respectively increased.3. Bortezomib could enhance the cytotoxicity of CIK cell against the K562and K562/ADR cells,which is positively correlated with The MICAmRNA of K562and K562/ADR cells.4. At the E:T ratio of10:1,20:1,the cytotoxic sensitivity of CIK to K562cells treated by bortezomib was higher than K562/ADR cells.5.K562and K562/ADR cells treated by CIKcells and Bortezomib shows significantly apoptosis effect.