The Mechanisms Of MiR-22-3p/miR-149-5p Responding To Folic Acid Deficiency And Regulating The Expression Of Methylenetetrahydrofolate Reductase And The Inhibition Of Cell Proliferation In Human Hepatocyte Cell Line

Folic acid(FA)is a core micronutrient involved in DNA synthesis and methylation,and its metabolism affects genomic stability.When intracellular folic acid metabolism changes,MicroRNA may respond and affect the expression of downstream target genes,the imbalance can also act on a carbon metabolism(OCM,or folate metabolism)can lead to DNA synthesis,methylation,amino acid metabolism of nuclear cell proliferation of these disorders are often associated with a variety of diseases or cancerMethylenetetrahydrofolate reductase(MTHFR)is used as a key "switch" gene through a carbon metabolism in DNA methylation and DNA synthesis,with abnormalities associated with genomic instability and various diseases or Tumor development and development are closely linked.The aim of this study was to investigate whether miR-22-3p / miR-149-5p responds to folic acid deficiency,which in turn affects the expression of MTHFR,which in turn affects its genome stability and explores its possible inhibition of cancer cell growth effect.In this study,Normal(HL-7702)and Cancerous Human Hepatocytes(QGY-7703)were treated with folic acid-deficient modified RPMI 1640 medium for 21 days.Dual luciferase reporter assay system was used to analyze the relationship between miRNA and MTHFR;Poly(A)plus tail method RT-qPCR was used to detect the expression of miR-22-3p / miR-149-5p in response to folate deficiency;RT-qPCR and Western blotting were used to detect the expression of MTHFR in the tested cells at the level of transcription and translation;CBMN-Cyt was used to detect genomic damage;CCK-8 method was used to detect the proliferation of hepatoma cells after transfection.The results showed that miR-22-3p / miR-149-5p was directly targeted to the 3'UTR of MTHFR gene.The expression of mi R-22-3p/miR-149-5p was up-regulated in QGY-7703 / HL-7702 cells,however,the transcription level of MTHFR was down-regulated in QGY-7703 cells and up-regulated in HL-7702 cells.Western blotting showed that folic acid deficiency resulted in down-regulation of MTHFR protein level in QGY-7703 cells,but remained unchanged in HL-7702 cells.It also showed that folic acid deficiency had different inhibitory effect on proliferation and tumor suppressing effect on normal Hepatocytes(tumor suppressor gene mRNA levels decreased)and hepatocellular carcinoma cells(tumor suppressor gene mRNA level increased).Genomic damage showed that HL-7702 cells lacked folic acid Resistance is stronger than QGY-7703 cells.MiR-22-3p / miR-149-5p transfected QGY-7703 cells,MTHFR mRNA levels decreased,cell proliferation capacity decreased at the same time.Our results indicate that miR-22-3p/miR-149-5p plays a different role in the regulation of MTHFR expression in human normal hepatocytes and human hepatocellular carcinoma cells under FA deficiency.The results suggest that miR-22-3p / miR-149-5p may inhibit the growth of hepatocellular carcinoma cells and promote its genomic instability under the condition of folic acid deficiency in human hepatocellular carcinoma cells.