Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:O76050 (neu)
 3,969 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interferons (IFNs) are known to possess potent antitumor properties. Previous studies have indicated that IFNs are capable of modulating the expression of various tumor suppressor genes and oncogenes. In this study, we looked at the effect of IFN-gamma on the neu/HER-2 proto-oncogene in the DU145, LNCaP, and PC-3 prostate cancer cell lines. IFN-gamma inhibited cell proliferation in both DU145 and PC-3 cells in a dose-dependent manner, whereas no inhibition of proliferation was seen in LNCaP cells. Correspondingly, IFN-gamma treatment of DU145 and PC-3 cells resulted in an increased production of the cyclin-dependent kinase inhibitor p21(WAF1), whereas no increase in p21(WAF1) was seen in LNCaP cells. In addition, IFN-gamma induced phosphorylation of signal transducer and activator of transcription (STAT) 1 in DU145 and PC-3 cells, but not in LNCaP cells. Consistent with these findings, we found that IFN-gamma treatment of DU145 and PC-3 cells caused a reduction in neu/HER-2 expression, with no change seen in the LNCaP cell line. Transfection and overexpression of the transcriptional coactivator p300 in PC-3 cells suppressed the reduction in neu/HER-2 expression after IFN-gamma treatment, suggesting a role for p300 in neu/HER-2 expression. The antiproliferative activity and p21(WAF1) production of these cells after IFN-gamma treatment were found to be reduced as well. We propose that the down-regulation of neu/HER-2 by IFN-gamma occurs via the interaction of phosphorylated STAT1 with p300 because IFN-gamma activities requiring phosphorylated STAT1 are reduced in cells overexpressing p300. These findings suggest that neu/HER-2 may play a role in the growth of some prostate cancers and that IFN-gamma may suppress such cancers by down-regulation of neu/HER-2.
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PMID:Down-regulation of neu/HER-2 by interferon-gamma in prostate cancer cells. 1091 67

Strong expression of human epidermal growth factor receptor 2 (HER-2)/neu in breast cancer has been associated with poor prognosis. Reduced expression of p27(Kip1), a cyclin-dependent kinase inhibitor, correlates with poor clinical outcome in breast cancer. In this study, we provide a correlation between these two important prognostic markers in patients with breast cancer. Breast tumor screening using immunohistochemistry indicated that downregulation of p27 correlated with HER-2/neu overexpression in studying 11 normal breast tissues and 51 primary breast carcinomas. We found HER-2/neu protein overexpression in 20 (41%) of 49 breast cancers and low p27 protein expression in 47 (92%) of 51 breast cancers. All 20 (100%) of the tumors that overexpressed HER-2/neu had low levels of p27 protein product; this correlation was statistically significant (P = 0.035). Decreasing p27 expression correlated with increasing HER-2/neu activity. Our results suggest that one function of the HER-2/neu product is to downregulate p27 expression in breast cancer. This study may be significant in selecting patients for HER-2/neu antibody therapy in the future. Mol. Carcinog. 30:169--175, 2001.
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PMID:Correlation of p27 protein expression with HER-2/neu expression in breast cancer. 1130 77

Overexpression of the epidermal growth factor receptor family member HER2 is found in approximately 30% of breast cancers and is a target for immunotherapy. Trastuzumab, a humanized monoclonal antibody against HER2, is cytostatic when added alone and highly successful in clinical settings when used in combination with other chemotherapeutic agents. Unfortunately, HER2 tumors in patients develop resistance to trastuzumab or metastasize to the brain, which is inaccessible to antibody therapy. Previously, we showed that the green tea polyphenol epigallocatechin-3 gallate (EGCG) inhibits growth and transformed phenotype of Her-2/neu-driven mouse mammary tumor cells. The different modes of action of EGCG and trastuzumab led us to hypothesize that EGCG will inhibit HER2-driven breast cancer cells resistant to trastuzumab. We studied trastuzumab-resistant BT474 human breast cancer cells, isolated by chronic trastuzumab exposure, and JIMT-1 breast cancer cells, derived from a pleural effusion in a patient who displayed clinical resistance to trastuzumab therapy. EGCG treatment caused a dose-dependent decrease in growth and cellular ATP production, and apoptosis at high concentrations. Akt activity was suppressed by EGCG leading to the induction of FOXO3a and target cyclin-dependent kinase inhibitor p27Kip1 levels. Thus, EGCG in combination with trastuzumab may provide a novel strategy for treatment of HER2-overexpressing breast cancers, given that EGCG can cross the blood-brain barrier.
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PMID:Trastuzumab-resistant HER2-driven breast cancer cells are sensitive to epigallocatechin-3 gallate. 1790 3