Effect of Compound Phylanthus urinaria Ⅱ in Regulating Expression of lncRNA CCAT1 in Hepatocellular Carcinoma HepG2 Cells / 中国实验方剂学杂志

ABSTRACT

Objective:To explore the anti-hepatoma effect of compound <italic>Phylanthus urinaria</italic> Ⅱ （ CPU Ⅱ） by inhibiting the expression of the long non-coding RNA （lncRNA） colon cancer associated transcript-1 （CCAT1） and restoring the expression of microRNA let-7a. Method:Real-time fluorescence quantitative polymerase chain reaction （PCR） was used to detect the expression of lncRNA CCAT1 in normal liver cells （LO2 cells） and hepatocellular carcinoma HepG2 cells， and the differences in expression between these two types of cells were compared. The methylthiazolyl tetrazolium（MTT） assay was used to detect the proliferation of HepG2 cells after treatment with different concentrations of CPU Ⅱ and 5-fluorouracil（5-FU） for 24， 48 and 72 h. Hepatocellular carcinoma HepG2 cells were cultured <italic>in vitro </italic>and set into three gropes： cell control group， CPU Ⅱ low-dose group （0.8 g·L^-1） and high-dose group （1.6 g·L^-1）. Real-time PCR was used to detect the mRNA expression of lncRNA CCAT1， microRNA let-7a and its target genes high mobility group protein A2（HMGA2）， and N-RAS in each grope. Western blot was used to detect the protein expression of HMGA2， and Cyclin D₁ in each grope. Result:As compared with LO2 cells， expression of lncRNA CCAT1 in HepG2 cells was significantly up-regulated （<italic>P</italic><0.05）. Results of MTT assay showed that the 50% inhibiting concentration（IC₅₀）of CPU Ⅱ and 5-FU on hepatocellular carcinoma HepG2 cells was 1.649， 0.044 648 g·L^-1respectively. As compared with the control group， CPU Ⅱ high-and low-dose groups （1.6， 0.8 g·L^-1） significantly inhibited the proliferation of HepG2 cells （<italic>P</italic><0.05）， and the effect was most remarkable in CPU Ⅱ high-dose group （<italic>P</italic><0.05）. The results of Real-time PCR showed that as compared with control group， the expression of lncRNA CCAT1 mRNA was significantly inhibited in CPU Ⅱ high-and low-dose groups （<italic>P</italic><0.05）， and the expression of microRNA let-7a mRNA was obviously up-regulated in high-dose group （<italic>P</italic><0.05）， but the expression of HMGA2 mRNA in CPU Ⅱ high-and low-dose groups as well as the expression of N-RAS mRNA in CPU Ⅱ low-dose group were down-regulated （<italic>P</italic><0.05）. Western blot results showed that as compared with the cell control group， the protein expression of HMGA2 and Cyclin D₁ in CPU Ⅱ high-and low-dose groups （1.6， 0.8 g·L^-1） was significantly down-regulated （<italic>P</italic><0.05）. Conclusion:CPU Ⅱ can inhibit the expression of lncRNA CCAT1， recover the expression of microRNA let-7a， and suppress the mRNA and protein expression of related downstream target genes in hepatoma cells line HepG2， thereby inhibiting the proliferation of hepatocellular carcinoma cells and exerting anti-hepatocellular carcinoma effect.