The Role Of Glutamine In Cancer Cell Proliferation

ObjectivesMetabolism of glutamate is an important part of cell life activity,especially for cancer cells,glutamine metabolism of its growth and reproduction has a particularly important function.It is well known that there is an abnormal metabolism in cancer cells that is different from normal cells.Normal cells under aerobic conditions,glycolysis is inhibited,the tumor cells in the case of oxygen is still sufficient to give priority to the use of glucose for glycolysis,resulting in a lot of lactic acid,and active use of glutamine,which is Warburg effect.And the main function of glutamine in cancer cell growth and reproduction is not particularly clear.Now the general view that the extensive use of glutamate in cancer cells is in order to cover tricarboxylic acid cycle,provide energy for the growth and reproduction of cancer cells.And this is not in line with our previous research.Therefore,the purpose of this study is to study the function of glutamine in the growth and proliferation of cancer cells,thus revealing the significance of abnormal glutamine metabolism in the development of cancers.Methods1.Validation of glutamine-induced cell death forms was verified using the laboratory’s patented method GC3 AI.2.Overexpress Bcl-2 and Bcl-xl in the Bcl-2 family gene to see whether the deprivation of glutamine-induced cell death was observed and whether glutamine-induced apoptosis was dependent on mitochondria.3.Determination of ATP by luciferase method to reflect the proliferation of different cell lines.4.Use of Z-vad,E-64,Cathepsin inhibitor and other inhibitors to determine the glutamine-induced apoptosis of the signal pathway.5.The expression of glutamine synthetase(GLUL)in various cell lines and the induction of GLUL induced by glutamine were detected by Western blot.6.Overexpress GLUL plasmids and down express GLUL plasmids is used to investigate whether GLUL is related to tumor cell growth and proliferation.7.The relationship between GLUL and glutamine transporter(ASCT2)and the clinical prognosis of the tumor was analyzed by large data.Results1.GC3 AI demonstrated glutamine deprivation induced cell death in the form of apoptosis.2.Overexpression of Bcl-2 and Bcl-xl in Bcl-2 family can protect against glutamine-induced apoptosis,but can not restore cell proliferation.Glutamine-induced apoptosis of tumor cells depends on mitochondria.3.The use of Z-vad,E-64,Cathepsin inhibitor and other inhibitors can be seen that glutamine-induced apoptosis to take Caspase classical apoptosis pathway.4.The other 19 kinds of amino acids and tricarboxylic acid sub-cycle intermediate metabolites can not effectively replace the function of glutamine for tumor cells.5.Adenine(A),guanine(G),cytosine(C)and uracil(U),these four bases can effectively prevent glutamine-induced apoptosis,but still can not restore the cancer cells proliferation.6.AGCU and several other amino acids together to prevent the glutamine-induced apoptosis,but also can effectively restore the proliferation of tumor cells.7.Western blot showed that the expression levels of glutamine synthetase(GLUL)in several cell lines were different,but they were relatively low.8.Western blot was used to detect the expression of GLUL in the cells after deprivation of glutamine.Some cells were induced to express,and some cells were not obvious.9.Overexpression of GLUL,in the case of glutamine deprivation,after adding glutamate(Glu),can be a good protection of tumor cell death and can greatly restore the proliferation of tumor cells;after down-expression of GLUL,glutamine-induced apoptosis is relatively increased.10.Large data analysis GLUL overexpression,breast cancer patients with better prognosis,ACST2 high expression,poor prognosis of breast cancer patients.Conclusions Cancer cells in the presence of abnormal glutamine metabolism,the current literature that glutamine in cancer cells,one of the most important role is to cover the carbon source of tricarboxylic acid cycle.Our results show that glutamine is mainly used to provide amide nitrogen for synthetic nucleotides and to synthesize other non-essential amino acids to provide amino nitrogen to ensure cancer cell growth.Glutamine deprivation in breast cancer cells induced glutamine synthetase(GLUL)expression,Glu as raw material to synthesize Gln.Although the inhibition of GLUL expression can accelerate the death caused by glutamine deprivation,but the high expression of GLUL in cancer tissue may mean that the cancer cells face the lack of glutamine,this situation can not guarantee the malignant growth of cancer cells.Therefore,GLUL may be associated with a good prognosis of patients with clinically breast cancer,also shows that malignant growth of cancer cells must be obtained from the outside of glutamine.Correspondingly,the glutamine transporter ASCT2 may promote malignant progression of the tumor,and its high expression may be associated with poor prognosis in patients with clinically breast cancer.