Document Detail

Dual EGFR/HER2 inhibition sensitizes prostate cancer cells to androgen withdrawal by suppressing ErbB3.
MedLine Citation:
PMID:  21844010     Owner:  NLM     Status:  MEDLINE    
PURPOSE: Patients with recurrent prostate cancer are commonly treated with androgen withdrawal therapy (AWT); however, almost all patients eventually progress to castration resistant prostate cancer (CRPC), indicating failure of AWT to eliminate androgen-sensitive prostate cancer. The overall goal of these studies is to determine whether dual inhibition of the receptor tyrosine kinases epidermal growth factor receptor (EGFR) and HER2 would prolong the effectiveness of this treatment in prostate cancer.
EXPERIMENTAL DESIGN: We used androgen-dependent LNCaP cells and its CRPC sublines LNCaP-AI and C4-2. Additional data were collected in pRNS-1-1 cells stably expressing a mutant androgen receptor (AR-T877A), and in nude mice harboring CWR22 tumors. Studies utilized EGFR inhibitors erlotinib and AG1478, and HER2 inhibitors trastuzumab and AG879.
RESULTS: Dual EGFR/HER2 inhibition induced apoptosis selectively in androgen-sensitive prostate cancer cells undergoing AWT, but not in the presence of androgens, or in CRPC cells. We show that AWT alone failed to induce significant apoptosis in androgen-dependent cells, due to AWT-induced increase in HER2 and ErbB3, which promoted survival by increasing Akt phosphorylation. AWT-induced ErbB3 stabilized the AR and stimulated PSA, while it was inactivated only by inhibition of both its dimerization partners EGFR and HER2 (prostate cancer cells do not express ErbB4); but not the inhibition of any one receptor alone, explaining the success of dual EGFR/HER2 inhibition in sensitizing androgen-dependent cells to AWT. The effectiveness of the inhibitors in suppressing growth correlated with its ability to prevent Akt phosphorylation.
CONCLUSION: These studies indicate that dual EGFR/HER2 inhibition, administered together with AWT, sensitize prostate cancer cells to apoptosis during AWT.
Liqun Chen; Benjamin A Mooso; Maitreyee K Jathal; Anisha Madhav; Sherra D Johnson; Elyse van Spyk; Margarita Mikhailova; Alexandra Zierenberg-Ripoll; Lingru Xue; Ruth L Vinall; Ralph W deVere White; Paramita M Ghosh
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2011-08-15
Journal Detail:
Title:  Clinical cancer research : an official journal of the American Association for Cancer Research     Volume:  17     ISSN:  1078-0432     ISO Abbreviation:  Clin. Cancer Res.     Publication Date:  2011 Oct 
Date Detail:
Created Date:  2011-10-04     Completed Date:  2012-01-27     Revised Date:  2014-09-21    
Medline Journal Info:
Nlm Unique ID:  9502500     Medline TA:  Clin Cancer Res     Country:  United States    
Other Details:
Languages:  eng     Pagination:  6218-28     Citation Subset:  IM    
Copyright Information:
©2011 AACR
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MeSH Terms
Androgen Antagonists / administration & dosage*
Antineoplastic Agents / therapeutic use*
Cell Line, Tumor
Mice, Nude
Neoplasms, Hormone-Dependent / drug therapy
Oncogene Protein v-akt / metabolism
Prostatic Neoplasms / drug therapy*
Receptor, Epidermal Growth Factor / antagonists & inhibitors*
Receptor, erbB-2 / antagonists & inhibitors*
Receptor, erbB-3 / antagonists & inhibitors*
Xenograft Model Antitumor Assays
Grant Support
R01 CA133209/CA/NCI NIH HHS; R01 CA133209-04/CA/NCI NIH HHS; R01CA133209/CA/NCI NIH HHS; R21 CA109057/CA/NCI NIH HHS; R21 CA109057-02S1/CA/NCI NIH HHS; R21CA109057/CA/NCI NIH HHS
Reg. No./Substance:
0/Androgen Antagonists; 0/Antineoplastic Agents; EC protein, human; EC, Epidermal Growth Factor; EC, erbB-2; EC, erbB-3; EC Protein v-akt

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