The Study On Induction Of The Epithelial-mesenchymal Transition Of The Human Lung Adenocarcinoma By Lactate Acid

Background and objective The growth rate of incidence and mortality is the most fast for lung cancer as a malignant tumor, the current five-year relative survival rate is only 18%, the reasons for lower long-term survival of patients with lung cancer are mainly due to tumor invasion and metastasis. Some studies show that about 80-90% of deaths are caused by tumor metastasis. Therefore, exploring the specific mechanisms of invasion and metastasis of lung cancer and taking appropriate preventive and treatment measures have significant clinical and social significance. It has been proved that invasion and metastasis in lung cancer is a continuous and developing process with multiple genes and steps involved in alteration of several signal transduction pathways. Recent studies show that during aerobic glycolysis, the accumulation of lactic acid in the tumor has a closely related with tumor metastasis, and epithelial-mesenchymal transition as an early event in tumor metastasis may be affected by the accumulation of lactic acid, so this study will explore the relationship between lactic acid and epithelial-mesenchymal transition, then study the effect of lactate on tumor metastasis. The epithelial mesenchymal transition process is regulated by a variety of factors, the transcription factor Snail is known to regulate epithelial cell marks as a key factor,therefore further disscuss whether lactic acid regulate epithelial-mesenchymal transition through the transcription factor Snail occurs. This article aims to further explore the link between lactate and epithelial-mesenchymal transition then explain its molecular mechanisms,which contribute to elucidate the molecular mechanism of tumor metastasis, tumor therapy to provide new targets and ideas.Materials and methods Selection non-small cell adenocarcinoma H1299 cell line as research subject.⑴ Transwell Chamber experiment was used to dectect the effect of lactate on tumor migrate,measured and analyzed the cell number that through the ECM membrane,then drawed the histogram.⑵Western blot was used to dectected the changes of biomarkers related to EMT before and after lactate disposition in H1299 cell line.⑶After transfection of LDHA si RNA, transfection efficiency and changes of EMT biomarkers was tested by Warburg blot.⑷ Western blot was used to dectected the changes of transcription factor Snail before and after lactate disposition in H1299 cell line.⑸RNA interference technique was used to silence the epression of LDHA gene,then transfection efficiency and changes of Snail was dectected by Warburg blot.⑹Western blot was used to detect protein level of EMT biomarkers before and after Snail silence under the disposition of lactate.Results 1、The invasive ability increased under the disposition of 20 m M lactate compared with that of 10 m M lactate(p=0.016).2、The protein level of E-cadherin increased while that of β-catenin decreased after the disposition of lactate.3、After transfection of LDHA si RNA,the protein level of LDHA decreased while that of E-cadherin increased(p=0.000,0.000).4、The protein level of Snail increased after the disposition of lactate(p<0.05);the protein levels of LDHA and Snail decreased after transfection of LDHA si RNA(p=0.000,0.000).5、.The protein level of Snail decreased after Snail silenced under the disposition of 10 m Mlactate(p=0.000),while the protein level of epithelial cell marker E-cadherin increased(p=0.000) and that of Fibronectin decreased(p=0.000).Conclusions 1、Lactate can promote the migration ability of H1299 cell line, the ability of cell migration has a positive correlation with the lactic acid concentration. 2、Lactate can induce the expression of epithelial cell marker and decrease that of mesenchymal cell in vitro or vivo, indicating that the occurrence of lactate can promote EMT. 3、Lactate can increase the protein expression of transcription factorSnail, silencing the expression of Snail can inhibit and partially reverse the EMT induced by lactate of H1299 cell line...