Details

Autor(en) / Beteiligte

• YUANBO LIU
• MAJUMDER, Samarpan
• MCCALL, Wesley
• SARTOR, Carolyn I
• MOHLER, James L
• GREGORY, Christopher W
• EARP, H. Shelton
• WHANG, Young E

Titel

Inhibition of HER-2/neu kinase impairs androgen receptor recruitment to the androgen responsive enhancer

Ist Teil von

• Cancer research (Chicago, Ill.), 2005-04, Vol.65 (8), p.3404-3409

Ort / Verlag

Philadelphia, PA: American Association for Cancer Research

Erscheinungsjahr

2005

Quelle

MEDLINE

Beschreibungen/Notizen

• Advanced prostate cancer invariably recurs despite androgen deprivation therapy. The androgen receptor (AR) likely plays a key role in this progression and in the continued survival and proliferation of prostate cancer cells in the low androgen environment. Cross-talk with growth factor receptors, such as epidermal growth factor receptor (EGFR) family, has been postulated as a potential mechanism to activate AR in recurrent prostate cancer. We have investigated the role of HER-2/neu (ErbB-2) tyrosine kinase in AR function by characterizing the effect of inhibiting endogenous HER-2 activity in LNCaP cells. We used two independent methods, expression of intracellular single-chain antibody against HER-2 and treatment with a novel dual EGFR/HER-2 kinase inhibitor GW572016 (lapatinib). Expression of intracellular HER-2 antibody scFv-5R and treatment with GW572016 inhibited HER-2 signaling. This HER-2 inhibition led to impairment of AR-mediated functions, such as androgen-stimulated growth and the induction of endogenous prostate-specific antigen (PSA) mRNA and protein. Androgen-stimulated recruitment of AR and histone acetylation at the androgen responsive enhancer of the PSA gene, detected by chromatin immunoprecipitation analysis, were impaired by HER-2 inhibition. GW572016 was more potent in its ability to inhibit PSA expression and AR recruitment and histone acetylation than the EGFR-selective kinase inhibitor ZD1839 (gefitinib), consistent with the HER-2 kinase playing the major role in AR regulation. These results show that HER-2 signaling is required for optimal transcriptional activity of AR in prostate cancer cells and suggest that HER-2 inhibition may provide a novel strategy to disrupt AR function in prostate cancer.