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

The understanding of intermediate endpoint biomarker expression in relation to the sequential events in bladder tumorigenesis establishes a useful approach for evaluating chemopreventive agents. Biomarkers may be genotypic or phenotypic and function as biomarkers of susceptibility, exposure, effect, or disease. This paper reviews several years of research on biomarkers and their use in monitoring chemoprevention therapy. In initial animal experiments, mice were dosed with N-butyl-N-(4-hydroxybutyl)nitrosamine (OH-BBN) while co-administering N-(4-hydroxyphenyl)retinamide (4-HPR). 4-HPR did not statistically reduce tumor incidence, but did affect tumor differentiation and, consequently, nuclear size and DNA ploidy. These results suggest that nuclear size and ploidy may function as intermediate endpoint biomarkers of effect for oncogenesis and that epigenetic as well as genetic mechanisms may be primary in the oncogenic process. Early biomarkers of effect which occur prior to genetic effects or chromosome aberration may portend a higher probability of being modulated by differentiating agents such as retinoids. In vitro studies demonstrated that RPMI-7666 cells cultured with a phorbol ester tumor promoter (12-O-tetradecanoyl-phorbol-13-acetate) could be redifferentiated with 13-cis-retinoic acid and dimethyl sulfoxide (DMSO). F-actin, a cytoskeletal biomarker with a presumed function in the epigenetic mechanisms of carcinogenesis, could also be normalized in HL-60 cells treated with 4-HPR or DMSO. A clinical evaluation of F-actin in patients with varying degrees of risk confirmed the value of F-actin as a differentiating biomarker useful for bladder cancer risk assessment. The clarification of when the phenotypic changes of F-actin occur in the oncogenic process was achieved when a variety of biochemical changes were mapped in the patients with bladder cancer. These studies confirmed that G-actin, a reciprocal form of F-actin, is increased relatively early in bladder cancer oncogenesis when multiple biomarkers are quantitated in the field, adjacent area, and the tumor. Comparison of each individual biomarker's expression from field, adjacent to tumor, and tumor, and subsequent cluster analysis of these biomarkers, indicated that the possible sequence of phenotypic expression of biomarkers in bladder cancer oncogenesis is from G-actin, to p300 antigen, to epidermal growth factor receptor (EGFR), to p185 (neu oncogene product), to DNA aneuploidy and, finally, to visual morphology.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Intermediate endpoint biomarkers for chemoprevention. 130 96

Breast cancer is one of the most common cancers and is a leading cause of mortality in women. The TG.NK transgenic mouse line expresses the c-neu breast cancer oncogene under the control of an MMTV promoter and appears to be a useful animal model for evaluation of intervention strategies to delay/prevent breast cancer. Fiber-rich nonpurified diet (NTP-2000), as compared to a purified diet (AIN-76A), has previously been shown to significantly delay the development of mammary cancer in the TG.NK model. Four-week old hemizygous TG.NK female mice with MMTV/c-neu oncogene were fed NTP-2000 diet containing the retinoid analogue 4-hydroxyphenyl retinamide (4-HPR) at 5 mM/kg or an arotinoid Ro 40-8757 at 2 and 3 mmol/kg for 26 weeks. The 4-HPR at 5 mmol/kg diet delayed the development of palpable tumors up to 24 weeks, but by 26 weeks, the incidence was not significantly different from the NTP-2000 diet control group. However, the 4-HPR diet markedly decreased the average weight of the tumors at 26 weeks. The 4-HPR diet also caused a significant increase in body weight without an increase in food consumption. Arotinoid Ro-40-8757 at both doses inhibited the development of mammary tumors for the duration of the study. However, the Ro 40-8757 at 3 mmol/kg appeared to be toxic as indicated by a significant depression of the average body weight with alopecia and skin scaling in some mice. Our observations with TG.NK transgenic mouse and fiber-rich diet (NTP-2000) indicate that the arotinoid Ro 40-8757 has a markedly higher inhibitory effect on the development of mammary cancer than 4-HPR. Studies to evaluate genetic changes and expression of hormonal receptors and growth factors associated with the inhibition of mammary cancer development by the retinoid analogues are in progress.
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PMID:Effect of retinoid analogues on mammary cancer in transgenic mice with c-neu breast cancer oncogene. 959 73

Breast cancer is one of the common cancers and is a leading cause of cancer mortality in women. The TG.NK transgenic mouse line on FVB strain background expresses the c-neu oncogene under the control of a MMTV promoter in mammary tissue and appears to be a useful animal model for evaluation of strategies to delay or prevent mammary cancer. Fiber-rich nonpurified diet (NTP-2000) and some retinoid analogues have delayed mammary cancer in the TG.NK model. Four week old hemizygous TG.NK female mice with MMTV/c-neu (erbB2) activated oncogene were fed NTP-2000 diet containing the retinoid analogue 4-hydroxyphenylretinamide (4-HPR) at 7 mmol/kg or the arotinoid Ro 40-8757 at 1.5 and 2.5 mmol/kg for 26 weeks. The 4-HPR at 7 mmol/kg diet delayed the development of palpable tumors up to 24 weeks, but by 26 weeks, the incidence markedly increased and was closer to the NTP-2000 diet control group. However, the 4-HPR diet markedly decreased the average weight of the tumors at 26 weeks with no decrease in multiplicity. The 4-HPR also caused significant increase in liver weights without an effect on body weight. Arotinoid Ro 40-8757 caused marked decrease in the number and branching of mammary ducts, and inhibited mammary tumor development with significant decrease in the incidence, multiplicity, and tumor weights compared to the NTP-2000 diet control. Arotinoid also caused a significant dose-related increase in liver weights without a significant effect on body weights. At the doses tested, the arotinoid but not 4-HPR decreased the circulating levels of IGF-1. However, there was no association between the IGF-1 levels and the size, incidence, or absence of tumors when evaluated for any treatment group or for all mice in the study irrespective of treatment. The oncogene erbB2 (c-neu) and the growth factor EGF expression were more prominent in the small tumors of the mice treated with arotinoid than in the larger tumors of the control group. PCNA staining was observed in areas where there was high erbB2 and EGF staining. The delay in onset of mammary tumors by the above retinoid analogues may be related to the delay in development of mammary glands.
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PMID:Changes associated with delay of mammary cancer by retinoid analogues in transgenic mice bearing c-neu oncogene. 1071 86

The retinoid N-(4-hydroxyphenyl)retinamide (4-HPR also known as fenretinide) is a potent inducer of apoptosis in breast cancer cells. We observed a 4.5-fold reduction in 4-HPR-mediated apoptosis in MCF-7 breast cancer cells transfected with HER2/neu (MCF-7/HER2) as compared with the parental MCF-7 (MCF-7/WT) cells. Blocking HER2/neu with trastuzumab (Herceptin) led to a six-fold increase in 4-HPR-induced apoptosis in HER2/neu-overexpressing cells. These data indicate that HER2/neu reduces the sensitivity of breast cancer cells to 4-HPR. We showed previously that nitric oxide (NO) is essential for 4-HPR to induce apoptosis in breast cancer cells. The inhibitory effects of the 4-HPR and trastuzumab combination correlated with the amount of NO produced in HER2/neu-overexpressing cells. When a NO synthase (NOS) inhibitor was used to block NO production, decreased apoptosis by the 4-HPR and trastuzumab combination was observed. Furthermore, 4-HPR-mediated NOSII expression was lower in MCF-7/HER2 than MCF-7/WT cells, but was increased by trastuzumab in HER2/neu-overexpressing cells. Here we report the novel findings that HER2/neu reduces the ability of 4-HPR to induce apoptosis in breast cancer cells, and that one mechanism by which HER2/neu increases the resistance of breast cancer cells to 4-HPR is by decreasing NOSII-mediated NO production.
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PMID:HER2/neu reduces the apoptotic effects of N-(4-hydroxyphenyl)retinamide (4-HPR) in breast cancer cells by decreasing nitric oxide production. 1455 87

We reported that HER2/neu reduces the sensitivity of breast cancer cells to N-(4-hydroxyphenyl)retinamide (4-HPR) by suppressing nitric oxide production. We show that HER2/neu uses Akt to induce cyclooxygenase-2 (COX-2) expression and that inhibition of Akt or COX-2 increases 4-HPR-induced apoptosis and nitric oxide production. Apoptosis induced by the 4-HPR and COX-2 inhibitor combination, although unaffected by an anti-HER2/neu antibody, was reversed by the COX-2 product prostaglandin E(2), indicating that COX-2 is a major mechanism by which HER2/neu suppresses 4-HPR apoptosis in breast cancer cells. Combining 4-HPR with COX-2 inhibitors may be a novel chemopreventive strategy against HER2/neu-overexpressing breast tumors.
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PMID:Cyclooxygenase-2 is essential for HER2/neu to suppress N- (4-hydroxyphenyl)retinamide apoptotic effects in breast cancer cells. 1497 14