Document Detail


Metastatic cells can escape the pro-apoptotic effects of TNF-α through increased autocrine IL-6/STAT3 signalling.
MedLine Citation:
PMID:  22194466     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
The liver is a common site for cancer metastases where the entrance of tumor cells has been shown to trigger a rapid inflammatory response. In considering how an inflammatory response may affect metastatic colonization in this setting, we hypothesized that tumor cells may acquire resistance to the pro-apoptotic and tumoricidal effects of TNF-α, a cytokine that is elevated in a pro-inflammatory tissue microenvironment. In this study, we investigated molecular mechanisms by which such resistance may emerge by using tumor cells in which the overexpression of the type I insulin-like growth factor receptor (IGF-IR) enhanced the inflammatory and metastatic capacity of poorly metastatic cells in the liver. Mechanistic investigations in vitro revealed that IGF-IR overexpression increased cell survival in the presence of high levels of TNF-α, in a manner associated with increased autocrine production of IL-6. In turn, tumor cell-derived IL-6 induced gp130 and IL-6R-dependent activation of STAT3, leading to reduced caspase-3 activation and apoptosis. We found that cell death resistance was dose-dependent with increasing IGF-I levels. Additionally, RNAi-mediated knockdown of either IL-6 or gp130 that established a blockade to autocrine STAT3 induction was sufficient to abolish the pro-survival effect of TNF-α and to inhibit liver metastasis. Taken together, our findings define an IGF-IR-mediated mechanism of cancer cell survival that is critical for metastatic colonization of the liver.
Authors:
Shun Li; Ni Wang; Pnina Brodt
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-12-22
Journal Detail:
Title:  Cancer research     Volume:  -     ISSN:  1538-7445     ISO Abbreviation:  -     Publication Date:  2011 Dec 
Date Detail:
Created Date:  2011-12-23     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  2984705R     Medline TA:  Cancer Res     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Medicine, McGill University.
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