The Inhibitory Effect Of Ribonucleic Acid Ⅱ On Cell Proliferation And Apoptosis In Human Leukemia Cells And Its Mechanism

Leukemia is a class of hematopoietic stem cell malignant clonal disease.Symptom in clinic appear as different degree of anemia,bleeding,infective fever and lymphadenectasis in liver and spleen,and born pain.The majority of researches indicate that the occurrence of leukemia is strongly complicated,related to various of elements such as chromosome breakage,oncogene activated by translocation,inactivation of anti-cancer genes.The main therapy is drug chemotherapy but the prognosis is poor,thus finding low toxicity and efficient anti-leukemia drugs is most critical currently.Ribonucleic acid Ⅱ is a member of immunonucleotides,which has functions of improving cellular immune and anti-cancer.Study on Ribonucleic acid Ⅱshowed that it could be an anti-cancer drug such as lung cancer and gastric carcinoma,but lacking in relative report of potential mechanism function to leukemia K562 and KG1 a cells.PI3K is an intracellular phosphatidylinositol kinase that has a very complicated proto-oncogene family.AKT which is a serine/threoninekinase and could be activated by the phosphatidylinositol being raised to the plasma membrane plays an important role in cell survival and apoptosis.PI3K/AKT signal pathway mediate p53 exerts rather important function in cell proliferation,cycle progression,survival and apoptotic.p53 can regulate the proliferation and apoptosis of cells by maintaining the genome stable DNA and be involved in the DNA repair process after damage.ROS is a series of reactive oxygen species produced by the aerobic cells in the process of metabolism.Endogenous ROS plays an important role in the process of apoptosis.Studies show that ROS is not only closely related to the PI3K/AKT signaling pathway and but also ROS levels are associated with activation of AKT during the process of apoptosis in many tumor cells.Many antineoplastic agents inducing tumor cell DNA fragmentation and apoptosis are all associated with triggering intracellular ROS changes.It is concluded that since PI3K/AKT signaling pathway and ROS are closely related to apoptosis and all are associated with DNA damage,this is consistent with the anti-tumor mechanism of ribonucleic acid II for injection.Therefore,we hypothesized that whether there is a link between the apoptosis of human leukemia cells induced by ribonucleic acid Ⅱ and the apoptosis induced by ROS and PI3K/AKT signaling pathway.ObjectiveThis paper aims at observing the effect of ribonucleic acid Ⅱ onapoptosis and cell cycle.The effect of ribonucleic acid Ⅱ on ROS and PI3K/AKT signaling pathway in K562 and KG1 a cells was explored for the first time and its possible mechanism was also investigated,providing experimental basis and clue for the clinical application of ribonucleic acidⅡ for the treatment of leukemia.MethodsHuman leukemia cell lines（K562 and KG1a）was cultured for 24 h in vitro,then treated ribonucleic acid Ⅱ at the concentration of 100 ³00mg·L^-1 for 12,24 and 48 h,respectively.The cell proliferation was detected by CCK-8;The cell cycle,ROS and apoptosis was measured by flow cytometry;morphological changes of apoptotic cells were determined by Hochest staining;The protein expression of p-PI3 K,p-AKT,p-MDM2,p53 and apoptotic related proteins Bax,Bcl-2,cleaved caspase-3 and cell-cycle related protein p21,Cyclin D1 and CDK4 were examined by Western Blot.Results1.K562 and KG1 a cells were treated with different concentration of ribonucleic acid Ⅱ after 12,24 and 48 h,the proliferation of cells was significantly inhibited by ribonucleic acid Ⅱ,in a time and dose-dependent manner respectively.2.The apoptotic rate of K562 cells increased from 4.75 % to 9.21 %,15.80 % and 29.36 %;the apoptotic rate of KG1 a increased from 6.91 % to10.06 %,56.49 % and 77.24 %;respectively（P <0.05）,apoptosis rates were concentration-dependent.3.The percentage of K562 cells in G0/G1 phase was increased from22.91 % to 28.35 %,37.43 %,42.40 %;the percentage of KG1 a cells in G0/G1 phase was increased from 23.57 % to 28.74 %,38.45 %,49.77 %;respectively（P<0.05）,the percentage of G2/M phase and S phase were gradually reduced.4.Hoechst staining revealed that ribonucleic acid Ⅱ could induce cell apoptosis,and cells in each group treated with ribonucleic acid Ⅱ had chromatin condensation gathered and typical apoptotic morphological changes in K562 and KG1 a cells,respectively.5.The results of WB suggested that the expression of P53,p21,Bax and cleaved caspase-3 obviously increased,but the expression of p-PI3 K,p-AKT,p-MDM2,Bcl-2 and Cyclin D1 protein significantly decreased.、6.Levels of ROS induced by ribonucleic acid Ⅱ showed a dose-dependent in K562 and KG1 a cells.7.The results of WB suggested that the decreased expression of p-PI3 K,p-AKT and increased expression of p53 in K562 and KG1 a cells treated with ribonucleic acid Ⅱand NAC.Conclusion1.Ribonucleic acid Ⅱ has the effect of inhibiting the proliferation,blocking cell cycle and inducing apoptosis of KG1 a and K562 cells.2.Ribonucleic acid Ⅱ could promote the apoptosis of K562 and KG1 a cells by regulating PI3K/AKT signal pathway,activating P53 and Caspase-3,regulate Bcl-2/Bax and down-regulate the expression of Cyclin D1 and CDK4 to induce apoptosis of leukemia cells.3.ROS could through regulate phosphorylation of PI3K/AKT and upregulation of p53 to promote cell apoptotic in human leukemia cell lines K562 and KG1 a.