Mechanism of Proteoglycan TPG-1 from Trametes robiniophila Inhibiting Growth of Human Hepatoma SK-HEP-1 Cells / 中国实验方剂学杂志

ABSTRACT

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.