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)

The MCF-7 cell line is a hormone-responsive human breast-cancer cell line, which has been extensively used in studies of estrogen regulation of cell growth. These studies have indicated that the growth stimulation of the MCF-7 cells by estrogens may be effected by an autocrine mechanism involving several growth factors, such as EGF, TGF alpha and IGF-I and their receptors. We have amplified and cloned tyrosine-kinase-related sequences from the MCF-7 cell mRNA using the polymerase chain reaction and characterized the partial cDNAs obtained by nucleic acid sequencing. Nine tyrosine kinase cDNAs and one serine/threonine kinase cDNA were identified among the amplified sequences. Four different tyrosine kinase genes encoding receptors for fibroblast growth factors (FGFs) were found to be expressed by the MCF-7 cells. In addition, differences were observed in the expression of these members of FGF receptor family in different breast-cancer cells. A putative tyrosine-kinase receptor and a novel serine/threonine kinase were preferentially expressed in estrogen-responsive tumor cell lines. However, no estrogen-dependent regulation of any of the novel tyrosine-kinase receptor mRNAs was found in any of the cell lines including the MCF-7 or ZR-75-I cells, where the expression of the neu proto-oncogene mRNA was decreased during estrogen treatment. The expression of several FGF receptors by breast-cancer cells suggests that FGFs may be involved in their growth regulation and tumorigenesis.
 ...
PMID:Analysis of tyrosine kinase mRNAs including four FGF receptor mRNAs expressed in MCF-7 breast-cancer cells. 131 Dec 87

Receptor status and gene amplification were studied in advanced human ovarian adenocarcinoma tissues, borderline and benign ovarian tumours and normal ovarian tissues. Sixty-five percent (53/82) of ovarian adenocarcinomas, 57% (8/14) of benign/borderline tumours and only 31% (5/16) of normal ovarian tissues studied showed specific 125I-EGF (epidermal growth factor) binding (median: 17; 10; and 0 fmol EGF-R/mg protein, respectively) and a significant increase in progesterone receptor (PgR) levels was observed in these groups (median: 5; 33; and 152 fmol/mg protein, respectively). No correlations were observed between the levels of EGF-R and the levels of either oestrogen receptors (ER) or PgR. All membrane samples of 25 adenocarcinomas studied by Scatchard analysis were positive for insulin-like growth-factor-I receptors (IGF-I-R) and contained higher IGF-I-R levels than membranes of 10 normal ovarian tissues, of which 9 were positive (median: 64 and 26 fmol IGF-I-R/mg membrane protein, respectively). Also, as measured by autoradiography, 37 adenocarcinoma tissues showed a higher expression of IGF-I-R (1.5+ to 4+) than sections derived from 10 normal ovarian tissues (1+). 125I-IGF-I binding was predominantly associated with epithelial tumour cells, the surrounding connective tissue was negative and in several samples high expression of IGF-I-R was found in areas of tumour necrosis. Southern blot analysis of DNAs isolated from 25 ovarian adenocarcinomas revealed no amplification of the IGF-I-R or the EGF-R gene. The HER2/neu gene was amplified only in 2 out of 3 histologically confirmed endometrioid adenocarcinomas studied but not in 22 other tumours. An amplification of the c-myc gene was observed in 28% (7/25) of the tumours. All c-myc-amplified tumours were PgR-negative. No rearrangement was observed for any of the genes studied. In conclusion, ovarian adenocarcinoma tissues show a decrease in PgR levels and an increased expression of IGF-I-R and EGF-R, in the absence of gene amplification, when compared to benign/borderline ovarian tumours and normal ovarian tissues. In addition, amplification of the c-myc and HER2/neu genes, without rearrangement of these genes, occurs in a minority of these tumours.
 ...
PMID:Receptors for hormones and growth factors and (onco)-gene amplification in human ovarian cancer. 132 50

The expression of growth factors, TGF-alpha, TGF-beta, IGF-I and neu oncogene product was studied immunohistochemically in the tissue of 120 benign and malignant human breasts. Growth factors were found only in benign or malignant mammary epithelial cells and not in stromal cells. Normal and benign lesions were found to be negative for reactivity with each antibody. Carcinoma in situ and invasive breast carcinomas demonstrated a significantly higher percentage of stained cells than that observed in benign lesions; forty (49%) of 82 invasive carcinomas were positive for TGF-alpha, 31 (38%) for TGF-beta, 31 (38%) for IGF-I and 34 (41%) for neu product. No overall correlations were found between expression of each growth factor and the clinical stage or degree of histologic differentiation of the carcinomas. A significant positive correlation was observed between ER status and IGF-I expression and between PgR status and TGF-beta expression. In the majority of the carcinomas, co-expression between TGF-alpha, TGF-beta and IGF-I was observed; the percentage of cases with parallel positive or negative expression of two growth factors was as follows; TGF-alpha - TGF-beta (70%), TGF-alpha - IGF-I (57%), TGF-beta - IGF-I (71%). The concomitant expression of TGF-alpha and neu oncogene product in cell surface was also observed. The relapse-free intervals of the patients were studied in association with expression of each growth factor. TGF-beta-positive tumors showed a significantly better prognosis than TGF-beta - negative tumors (within the first 2 years of observation). However, TGF-alpha, IGF-I and neu overexpression showed no effect on the prognosis of the patients.
 ...
PMID:Immunohistochemical demonstration of growth factors, TGF-alpha, TGF-beta, IGF-I and neu oncogene product in benign and malignant human breast tissues. 197 32

Recent studies have suggested that insulin-like growth factors (IGFs) and insulin-like growth factor binding proteins (IGFBPs) may be implicated in the development and progression of breast cancer. Prostate-specific antigen (PSA), a serine protease, may play a role in the regulation of IGFs' function through cleavage of IGFBP-3, resulting in release of active IGFs from IGFBP-3. As IGFs, IGFBPs and PSA are all present in breast cancer, possible associations among these proteins were speculated. In this study, we have measured PSA, IGF-I, IGF-II, IGFBP-1 and IGFBP-3 in tumour tissue cytosols from 200 women with primary breast cancer, and have examined relationships between IGFs or IGFBPs and PSA along with other markers, including p53 protein, steroid hormone receptors (oestrogen and progesterone), cathepsin-D, epidermal growth factor receptor, Her-2/neu protein, S-phase fraction and DNA ploidy. Correlations or associations between PSA and IGF-I, IGF-II, IGFBP-1 or IGFBP-3 were not observed. IGF-II was positively correlated with both IGFBP-3 and IGFBP-1. IGF-I was not associated with either of the two binding proteins, nor with IGF-II. Both IGF-II and IGFBP-3 were inversely associated with the oestrogen receptor, and IGFBP-3 was also positively associated with S-phase fraction. Our finding of IGF-II and IGFBP-3 in association with unfavourable prognostic indicators of breast cancer suggests that IGFs may be involved in the progression of breast cancer.
 ...
PMID:Associations between insulin-like growth factors and their binding proteins and other prognostic indicators in breast cancer. 888 11

Obesity is a risk factor for postmenopausal breast cancer and is associated with shortened latency and/or increased mammary tumor (MT) incidence in animals. Elevated body weight is usually associated with hormone-responsive tumors. In agreement with these data we previously showed that latency of hormone-responsive MTs in MMTV-TGF-alpha mice with diet-induced obesity was significantly shortened. Here, we used the same protocol to determine the impact of diet-induced obesity on estrogen receptor-negative MT development in MMTV-neu (strain 202) mice. Mice were fed a low-fat diet (n=20) or a high-fat diet (n=54) from 10 wk of age. Body weight at 19 wk of age was used to assign high-fat mice to obesity-prone, overweight, and obesity-resistant groups. Mice were euthanized due to MT size or at 85 wk of age. Final body weights of obesity-prone mice were heaviest, and those of obesity-resistant and low-fat groups were similar. Fat pad weights were heaviest in obesity-prone mice followed by overweight and obesity-resistant groups, and lightest in low-fat mice. Serum IGF-I levels were similar for low-fat and high-fat mice, whereas leptin was higher in high-fat mice (P <0.0001). MT latency, incidence, metastasis, and burden were similar for all groups. These findings support that obesity is not a risk factor for development of estrogen-negative breast cancer.
 ...
PMID:Diet-induced obesity and mammary tumor development in MMTV-neu female mice. 1562 64

Obesity is a risk factor for postmenopausal breast cancer and is associated with poor prognosis. Leptin, a cytokine synthesized in adipose tissue, has been implicated as a link between obesity and breast cancer. In the present study, the effects of leptin on cell proliferation and proteins associated with leptin signaling and/or breast cell growth were investigated in ER-positive, MCF-7, T47-D and MDA-MB-361, and ER-negative, MDA-MB-231 and SK-BR-3, breast cancer cell lines. MDA-MB-361 and SK-BR-3 also overexpress HER2/neu. For proliferation assays, 96-well plates were used and for protein determinations cells were synchronized in 6-well plates for 18-24 h in serum-free medium. Leptin was added at 0, 5, 10, 25, 50 and 100 ng/ml for 24 and 48 h. For Western blot analyses, protein extracts were probed for Ob-Rb, Ob-R, leptin, Jak2, PI3K, Stat3, p-Stat3, PCNA, cyclin D1, Cox-2, VEGF, Bcl-2, Bcl-xL, Bax, insulin, IGF-I, IGFBP3, IGF-IRalpha, aromatase, CYP1A1 and CYP1B1. Overall, except for MCF-7 cells, leptin stimulated proliferation in all lines. MCF-7 cells expressed higher levels of Ob-Rb, Jak2, PI3K, Stat3 and p-Stat3 in a dose-dependent manner to 50 ng/ml at 24 h; and IGF-IRalpha increased at 24 h. Cyclin D1 and Cox-2 levels increased with leptin treatment. Higher CYP1B1 expression was observed at both 24 and 48 h. In MDA-MB-231 cells, p-Stat3 and Bcl-xL were increased at 48 h; whereas PCNA and cyclin D1 expression increased in leptin-treated cells at 24 and 48 h. In T47-D cells, Jak2 and Stat3 were elevated at higher leptin concentrations at 24 and 48 h. However, p-Stat3 and PCNA demonstrated an increase only in 48-h leptin-treated cells. Furthermore, cyclin D1 exhibited higher expression at both 24 and 48 h, while Bcl-xL expression was lower with increasing concentrations of leptin at 48 h. In MDA-MB-361 cells, Ob-Rb and VEGF increased at 24 and 48 h; whereas PI3K, Stat3, PCNA and insulin levels increased in leptin-treated MDA-MB-361 cells after 48 h. Bcl-2 and IGF-IRalpha were decreased at 24 h and a dose-dependent increase at 48 h was noted. Higher expression of CYP1B1 was observed with leptin for 24 h. In SK-BR-3 cells, Ob-R increased at both 24 and 48 h. A similar trend was found for IGF-I and IGFBP3 expression. Higher levels of Jak2 and PI3K were observed after 24 h. Interestingly, there was a gradual increase of leptin expression at 24 h, but a gradual decrease at 48 h in relation to the dose of leptin. In contrast, PCNA and IGF-IRalpha showed a decline at 24 h and an increase at 48 h. Elevated levels of cyclin D1, VEGF and Bax were detected at 48 h in cells and increased Cox-2 expression was observed at 24 h. These data indicate that leptin may influence breast cancer development in relation to ER status as well as to the presence or absence of HER2. Continued study on leptin may be helpful for a better understanding of breast cancer development in obese women.
 ...
PMID:Effects of leptin on human breast cancer cell lines in relationship to estrogen receptor and HER2 status. 1748 72