Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C1864663 (HCC)
 2,985 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Signal regulatory protein (SIRP) alpha1 is a member of the SIRP family that undergoes tyrosine phosphorylation and binds SHP-2 tyrosine phosphatase in response to various mitogens. The expression levels of SIRPalpha1 were decreased in HCC tissues, compared with the matched normal tissues. Exogenous expression of wild type SIRPalpha1, but not of a mutant SIRPalpha1 lacking the tyrosine phosphorylation sites, in SIRPalpha1-negative Huh7 human HCC cells resulted in suppression of tumor cell growth both in vitro and in vivo. Treatment of Huh7 transfectants with EGF or HGF induced tyrosine phosphorylation of SIRPalpha1 and its association with SHP-2, which were accompanied by reduced ERK1 activation. Expression of SIRPalpha1 significantly suppressed activation of NF-kappaB and also sensitized Huh7 cells to TNFalpha or cisplatin-induced cell death. In addition, SIRPalpha1-transfected Huh7 cells displayed reduced cell migration and cell spreading in a fashion that was dependent on SIRPalpha1/SHP-2 complex formation. In conclusion, a negative regulatory effect of SIRPalpha1 on hepatocarcinogenesis is exerted, at least in part, through inhibition of ERK and NF-kappaB pathways.
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PMID:Negative regulation of hepatocellular carcinoma cell growth by signal regulatory protein alpha1. 1534

The purpose of this study is to investigate the effect of a purified polysaccharide (PPPF) from pumpkin fruit on the Janus activated kinase (JAK)/signal transducer and activator of transcription (STAT) signaling during apoptotic process. The results showed that PPPF or STAT3 siRNA inhibits the cell growth of HepG2 cells via induction of apoptosis. Moreover, PPPF is able to suppress both constitutive and IL-6-induced phosphorylation of STAT3 (on Tyr705) and subsequent nuclear translocation in cancer cells. Such inhibition is found to be achieved through down-regulation of constitutive phosphorylation of JAK2, but not JAk1, c-Src, ERK1/2, and Akt, which means STAT3 tyrosine phosphorylation in HepG2 cells following PPPF treatment is associated with a reduction in JAK2 activity. In addition, the protein expression of SHP-1 was increased in cells in response to PPPF treatment, whereas SHP-2, SOCS-1 and SCOS-3 protein expression remain unchanged. In vivo animal experiment also indicated that PPPF had a potent inhibitory effect on tumor growth in mice bearing HepG2 xenograft tumors. Thus we can conclude that PPPF directly induces apoptotic cell death of HepG2 cells via down-regulation of the JAK2/STAT3 signal transduction pathways, which may facilitates the development of a therapeutic strategy for treating HCC.
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PMID:A pumpkin polysaccharide induces apoptosis by inhibiting the JAK2/STAT3 pathway in human hepatoma HepG2 cells. 2863 59