RESUMEN
ObjectiveProteoglycan TPG-1 isolated from Trametes robiniophila（Huaier） has proved to have anti-hepatoma activity， and this paper aims to explore the molecular mechanism. MethodHuman hepatoma SK-HEP-1 cells were treated with TPG-1 （0， 0.05， 0.1， 0.25， 0.5， 1 g·L-1）. Then cell survival was detected by methyl thiazolyl tetrazolium （MTT） and apoptosis by flow cytometry. In addition， expression of genes in SK-HEP-1 cells treated with or without TPG-1 was examined by DNA microarray to preliminarily explore the anti-hepatoma molecular mechanism of TPG-1. ResultTPG-1 inhibited the proliferation of SK-HEP-1 cells as compared with the blank group （P<0.01）. After treatment with 1 g·L-1 TPG-1 for 48 h， the apoptosis rate of SK-HEP-1 cells increased （P<0.01）， and TPG-1 promoted the cleavage of cysteinyl aspartate specific proteinase （Caspase）-3 and Caspase-7， the key mediators of apoptosis （P<0.01）. Additionally， TPG-1 （1 g·L-1） suppressed the migration of SK-HEP-1 cells （P<0.05）. A total of 971 differentially expressed genes （DEGs） were identified in SK-HEP-1 cells after treatment with TPG-1， with 486 up-regulated and 485 down-regulated. These DEGs were mainly involved in the Gene Ontology （GO） terms of interleukin-6 （IL-6） biosynthesis， antigen processing and presentation， superoxide dismutase activity， positive regulation of mitogen-activated protein kinase kinase kinase （MAPKKK） cascade， nature killer （NK） cell chemotaxis， and chemokine biosynthesis， and the Kyoto Encyclopedia of Genes and Genomes （KEGG） pathways of nucleotide-binding oligomerization domain （NOD）-like receptor signaling pathway， apoptosis， Toll-like receptor signaling pathway， retinoic acid-inducible gene-Ⅰ （RIG-Ⅰ）-like receptor signaling pathway， T-cell receptor signaling pathway， and chemokine signaling pathway. Western blot results showed that TPG-1 （1 g·L-1） activated mitogen-activated protein kinase （MAPK） signaling pathway in SK-HEP-1 cells （P<0.01）. ConclusionProteoglycan TPG-1 inhibited the proliferation and migration， and induced apoptosis of human hepatoma SK-HEP-1 cells. Up-regulation of MAPK signaling pathway may be responsible for the growth inhibition of human hepatoma SK-HEP-1 cells by TPG-1.
RESUMEN
The purpose of this study was to investigate the effect of Huaier on autophagy of human hepatoma SK-HEP-1 cells and the effect of autophagy on the proliferation of SK-HEP-1 cells. CCK-8 assay was used to evaluate the effect of Huaier on the proliferation of SK-HEP-1 cells under different concentrations and different times. Acridine orange staining was used to measure the effect of Huaier on the autolysosome formation in SK-HEP-1 cells. Immunofluorescence assay was applied to examine the effect of Huaier on the expression and distribution of autophagy marker LC3 in SK-HEP-1 cells. In addition， LC3 expression was also checked by immunoblot analysis in the presence of Huaier. At last， the effects of Huaier in combination with autophagy inhibitor bafilomycin A1 on the proliferation of SK-HEP-1 cells was detected by CCK-8 assay. The results showed that Huaier aqueous extract significantly inhibited the proliferation of human hepatoma SK-HEP-1 cells in a dose- and time-dependent manner. Huaier aqueous extract dramatically promoted the formation of autolysosome in SK-HEP-1 cells. Moreover， Huaier markedly increased the number and intensity of intracellular LC3 fluorescent puncta and up-regulated LC3-Ⅱ expression. These data indicated that Huaier evidently activated autophagy of SK-HEP-1 cells. Additionally， autophagy inhibition significantly attenuated the sensitivity of SK-HEP-1 cells to Huaier treatment. Therefore， autophagy activation is involved in the inhibitory effects of Huaier on the proliferation of human hepatoma SK-HEP-1 cells.