Role Of LDHB In The Regulation Of Tumor Cell Development And Growth By Lactic Acid

Objective: Cancer is one of the major diseases that endanger human health.The rapid proliferation of tumor tissue can cause severe hypoxia and energy metabolism imbalance in local tissues.This eventually leads to increased aerobic glycolysis and lactic acid production.This aerobic glycolysis will eventually lead to an increase in lactic acid levels in the tumor microenvironment and play an important role in tumor invasion,migration,and immune escape.However,the effect and mechanism of increased lactate levels in the tumor microenvironment on tumor cells,especially the corresponding normal cells,is not yet clear.We speculate that the increased lactic acid level not only helps tumor cells proliferate,but also stresses normal cells around tumor cells to change their own energy metabolism.By up-regulating LDHB expression,normal cells undergo tumor-like energy metabolism.Compare the expression of LDHB between different tumor cells and corresponding normal cells;explore the effect of LDHB on the proliferation ability of different tumor cells and normal cells.Inhibition of LDHB gene expression will inhibit abnormal metabolism in normal cells and is expected to become a new target for anti-tumor effects.This article takes LDHB as the target and combines gene knockout and gene overexpression technology.The effect of lactic acid on tumor and corresponding normal cell proliferation and the relationship with LDHB were systematically studied.We strive to explore new mechanisms of tumorigenesis and provide a theoretical basis for finding new targets for antitumor drugs and the development of new antitumor drugs.Methods: Western blot was used to detect the expression of LDHB protein between different tumor cells and normal cells.Normal cell lines stably overexpressed LDHB and tumor cell lines stably knocked out LDHB.The MTT assay detected the viability of tumor cells and normal cells.EDU tested the proliferation of tumor cells and normal cells.Wound healing assay was applied to examine cell migration ability of normal cell lines after over-expression of LDHB.Results: 1.Western blot results showed that the expression of LDHB protein in normal cells(breast cancer MDA-MB-231,liver cancer HepG2,and gastric cancer HGC-27)was lower than that in tumor cells breast cell MCF-10 A,liver cell L02,and gastric cell GES-1).2.The results of MTT showed that low glucose and different concentrations(10 mmol / L,20 mmol / L,40 mmol / L)of lactic acid were used to treat tumor cells for 72 h.Lactic acid can promote the proliferation of tumor cells in different degrees.The results are consistent with the results of the EDU experiment(low glucose supply and 40 mmol / L lactic acid treatment for 72h).3.Tumor cell lines(breast cancer MDA-MB-231,liver cancer HepG2,and gastric cancer cell HGC-27)with low shLDHB expression were treated with low glucose supply and different concentrations of lactic acid for 72 h.MTT test results showed that compared with the control group,tumor cells stably expressing shLDHB had more obvious damage.The results are consistent with the results of the EDU experiment(low glucose supply and 40 mmol / L lactic acid treatment for 72h).4.The results of MTT showed that low glucose and different concentrations(10 mmol / L,20 mmol / L,40 mmol / L)of lactic acid were used to treat normal cells for 72 h.Lactic acid has different degrees of damage to normal cells and inhibits their cell proliferation.The results are consistent with the results of the EDU experiment(low glucose supply and 40 mmol / L lactic acid treatment for 72h).5.Western blot results showed that liver cells L02 and gastric cells GES-1 were treated with different concentrations(10 mmol / L,20 mmol / L,40 mmol / L)of lactic acid,and breast cancer cells MCF-10 A were treated with different concentrations(10 mmol / L,20 mmol / L,30 mmol / L)of lactic acid after 96 h.The LDHB protein expression level of normal cells not killed was significantly higher than that of the control group.6.Low glucose supply and different concentrations(10 mmol / L,20 mmol / L,40 mmol / L)of lactic acid treated overexpressed LDHB normal cell lines(breast cell MCF-10 A,stem cell L02 and gastric cell GES-1)for 72 h.MTT test results showed that compared with the control group,the damage of normal cells overexpressing LDHB was reduced.Low concentrations of lactic acid promote the growth of normal cells that overexpress LDHB.The results are consistent with the results of the EDU experiment(low glucose supply and 40 mmol / L lactic acid treatment for 72h).Conclusion:1.LDHB protein expression levels of breast cancer cell MDA-MB-231,liver cancer cell HepG2 and gastric cancer cell HGC-27 are higher than corresponding normal cells(mammary epithelial cell MCF-10 A,liver cell L02 and gastric mucosal cell GES-1).2.Different concentrations of lactic acid(10 mmol / L,20 mmol / L,40 mmol / L)can promote the proliferation of breast cancer cell MDA-MB-231,liver cancer cell HepG2 and gastric cancer cell HGC-27 with high expression of LDHB to different degrees under low glucose culture conditions.However,it has different damage effects on breast epithelial cells MCF-10 A,hepatocytes L02 and gastric mucosal cells GES-1,and inhibits their proliferation under low glucose culture conditions.3.Overexpression of LDHB in normal liver cells L02 and gastric mucosal cells GES-1 can promote their cell proliferation in a low-sugar and high-lactic acid environment.4.Long-term "lactic acid stress"(10-40 mmol / L for 96 hours)can induce upregulation of LDHB expression in normal mammary epithelial cells MCF-10 A,hepatocytes L02 and gastric mucosal cells GES-1 under low glucose culture conditions.