MiR-449a Suppresses Glycolysis Through Targeting LDHA In Human Lung Cancer

BackgroundAberrantly increased activity of glycolysis is a common phenomenon in tumors.Uncovering the underlying mechanisms responsible for the up-regulation of glycolytic enzymes would help develop novel therapeutics for cancer treatment.A number of miRNAs have been shown to participate in the regulation of glycolysis.This study aimed to investigate the regulation of LDHA,an enzyme catalyzing the last step of glycolysis,by miR-449 a in lung cancer.Methods1 The expression of miR-449 a was up-regulated in the lung cancer cells when infected with lentivirus and the expression of miR-449 a was down-regulated by miR-449 a inhibitor.Then the expression of LDHA mRNA and protein were detected by qRT-PCR and Western blot,respectively.2 Through the detection of glucose consumption,LDHA activity and lactic acid in the culture medium,to study the effect of miR-449 a and LDHA on the metabolism of lung cancer cells.3 Through the growth experiment,soft agar colony formation assay to study the effect of miR-449 a on lung cell proliferation in vitro,and when co-transfected with LDHA and miR-449 a,whether lung cell proliferation would be partially recovered.Subcutaneous tumor formation in nude mice was used to study the effect of miR-449 a on the ability of subcutaneous tumor formation of lung cancer cells in vivo,and when co-transfected with LDHA and miR-449 a,whether the ability of subcutaneous tumor formation of lung cancer cells would be partially recovered.4 The expression of miR-449 a and LDHA mRNA were detected by qRT-PCR in lung cancer tissue samples and corresponding adjacent tissues.Western blot was used to detect the expression level of LDHA protein in lung cancer tissues and corresponding adjacent tissues.Then the correlation between miR-449 a and LDHA was analyzed.Results1 The results showed that miR-449 a decreased the levels of both LDHA mRNA and protein in tumor cells.2 miR-449 a could inhibit glucose consumption,LDHA activity and lactic acid production in lung cancer cells,when LDHA was co-infected with miR-449 a,there occurred a “rescue” of the glucose consumption,LDHA activity and lactic acid production in lung cancer cells.3 miR-449 a could inhibit the proliferation of lung cancer cells and the number of soft agar colony formation,and the recovery of LDHA could partly restore the proliferation of lung cancer cells and the number of soft agar colony formation in vitro.Furthermore miR-449 a could inhibit the ability of subcutaneous tumor formation in nude mice,and the recovery of LDHA could partly restore the ability of subcutaneous tumor formation in nude mice.4 Human tissue samples showed that the expression of miR-449 a in lung cancer cells was lower than that in adjacent tissues,and the expression level of LDHA was higher than that in adjacent tissues.There was a negative correlation between LDHA and miR-449 a expression in human tissue samples.ConclusionsOur study demonstrated that miR-449 a inhibited glycolysis and tumor growth of lung cancer through suppressing the expression of LDHA.Inhibiting glycolysis through targeting LDHA may represent a potential therapeutic approach for lung cancer treatment.