ABSTRACT
To investigate the inhibitory effects of two xanthone compounds, 1-hydroxy-2,3,4,8-4 methoxy xanthone(here in after referred to as Fr15) and 1-hydroxy-2,3,4,6-4 methoxy xanthone(here in after referred to as Fr17), on the proliferation of hepatocellular carcinoma cells HepG2, and to further investigate their mechanism in combination with transcriptomics. Cell counting was used to detect the effects of two kinds of xanthone compounds Fr15 and Fr17(0, 0.03, 0.15, 0.3 mmoL·L~(-1)) on the proliferation of HepG2 cells; the effects of the two compounds Fr15 and Fr17 on HepG2 cell cycle were detected by flow cytometry; the changes of autophagosomes count in cells were observed under fluorescence microscope; the expression of autophagy marker proteins autophagy marker proteins SQSTM 1(p62) and microtubule associated protein 1 light chain 3 Ⅰ/Ⅱ(LC3 Ⅰ/Ⅱ) in the cells was detected by Western blot; the differentially expressed genes between the control group and the experimental group were analyzed by RNA-seq transcriptome sequencing; qRT-PCR was used to verify the differentially expressed genes in sequencing. The results showed that compounds Fr15 and Fr17 inhibited the proliferation of HepG2 cells with the increase of drug concentration and time. Flow cytometry showed that compounds Fr15 and Fr17 had little effect on HepG2 cell cycle. Fluorescence microscopy results showed that the number of autophagosomes in cells increased with the increase of drug concentration. Western blot showed that the expression of p62 protein was decreased and the expression of LC3-Ⅱ protein was significantly increased after drug addition. The results of RNA sequencing showed that 26 102 and 52 351 differentially expressed genes were obtained in Fr15 and Fr17 respectively. Analysis of KEGG showed that drug treatment had a great effect on autophagy pathway. qRT-PCR verified that 6 up-regulated genes were related to autophagy, and their trend was consis-tent with sequencing results, where all 6 genes showed an up-regulated trend. Two xanthone compounds Fr15 and Fr17 may inhibit proliferation of HepG2 cells by inducing autophagy.