Document Detail


Metformin targets Stat3 to inhibit cell growth and induce apoptosis in triple-negative breast cancers.
MedLine Citation:
PMID:  22189713     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
A distinct group of breast cancers, called "basal" or "triple-negative" (TN) cancers express both basal cytokeratins and the epidermal growth factor receptor, but fail to express estrogen receptors, progesterone receptors or HER2 and have stem-like or mesenchymal features. They are particularly aggressive, are frequently chemo-resistant, with p53 mutation, up-regulation of IL-6 and Stat3. Because TN cells are particularly sensitive to the anti-diabetic agent metformin, we hypothesized that it may target JAK2/Stat3 signaling. The effects of metformin upon Stat3 expression and activation were examined in four human TN cell lines. Metformin's effects were also studied in sublines with forced over-expression of constitutively active (CA) Stat3, as well as lines with stable knockdown of Stat3. Metformin inhibited Stat3 activation (P-Stat3) at Tyr705 and Ser727 and downstream signaling in each of the four parental cell lines. CA-Stat3 transfection attenuated, whereas Stat3 knockdown enhanced, the effects of metformin upon growth inhibition and apoptosis induction. A Stat3 specific inhibitor acted synergistically with metformin in reducing cell growth and inducing apoptosis. An mTOR inhibitor showed no significant interaction with metformin. In summary, Stat3 is a critical regulator of metformin action in TN cancer cells, providing the potential for enhancing metformin's efficacy in the clinical setting.
Authors:
Xin-Sheng Deng; Shuiliang Wang; Anlong Deng; Bolin Liu; Susan M Edgerton; Stuart E Lind; Reema Wahdan-Alaswad; Ann D Thor
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-1-15
Journal Detail:
Title:  Cell cycle (Georgetown, Tex.)     Volume:  11     ISSN:  1551-4005     ISO Abbreviation:  -     Publication Date:  2012 Jan 
Date Detail:
Created Date:  2011-12-22     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101137841     Medline TA:  Cell Cycle     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Affiliation:
Department of Pathology; University of Colorado Denver; Denver, CO USA.
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