Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Tamoxifen is useful in the treatment of breast cancer, but its effects in metastatic disease are rarely long term, and development of resistance to the drug is common. In vitro and in vivo data demonstrate anti-neoplastic (anti-proliferative) effects of somatostatin analogues, which may occur via binding to somatostatin receptors on the neoplastic cells, and/or via reductions in insulin-like growth factor-1 bioactivity. Moreover, several lines of evidence from in vitro and in vivo studies indicate that the long-acting somatostatin analogue octreotide enhances the anti-neoplastic effects of anti-oestrogenic agents such as tamoxifen. The anti-oestrogen-somatostatin approach appears to have a favourable long-term toxicity profile. Large-scale clinical trials are currently being planned to investigate the efficacy of combined tamoxifen plus octreotide therapy compared to tamoxifen alone in patients with breast cancer.
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PMID:Enhancement of the anti-neoplastic effects of tamoxifen by somatostatin analogues. 881 63

Neuroendocrine (NE) cells are involved in gastro-enteropancreatic (GEP) neoplasms. Biological markers, such as peptides hypersecreted by biologically active NE tumours, aid in the evaluation of response to treatment. For surgically untreatable NE neoplasms, the therapeutic approach remains undefined. Somatostatin analogues, particularly octreotide, can control the clinical effects of hormone overproduction in NE neoplasms and they have revolutionised individualised treatment, particularly for biologically active tumours. So far, like interferon, octreotide used at standard dosages has failed to control neoplastic growth per se. We gave the somatostatin analogue lanreotide to women with advanced breast cancer and to colorectal carcinoma patients. Results confirmed that inhibition of the production of insulin-like growth factor-1, which plays an important role in neoplastic proliferation, could be obtained using the highest doses. Considering these data, we started a clinical trial of 58 patients affected by NE tumours, treated with two sequential doses (500 and 1,000 micrograms subcutaneously t.i.d.) of octreotide. Long-term disease stabilisation (> 6 months) was achieved in 43% of patients but an objective response in only 3%. Good control of clinical symptoms and markers was obtained in 73 and 77% of cases, respectively. Toxicity was negligible. Somatostatin analogues should be carefully evaluated at high doses for possible anti-proliferative effects. Studies are currently investigating their promising association with interferon.
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PMID:The role of somatostatin analogues in the treatment of gastro-enteropancreatic endocrine tumours. 881 75

We have investigated the autocrine regulation of insulin-like growth factor-II (IGF-II) signaling by the insulin-like growth factor-I receptor (IGF-IR) and the insulin-like growth factor-II/mannose 6-phosphate receptor (IGF-IIR) in MCF-7 breast cancer cells, employing retroviruses encoding both IGF-I, IGF-II, and IGF-I and II mutants with reductions in affinity for either the IGF-IR or the IGF-IIR. These studies revealed reciprocal roles for IGF-IR and IGF-IIR affinity in the regulation of autocrine IGF-II activity. IGF-IR affinity was required for serum-free proliferation but also for efficient IGF-II secretion. In contrast, cellular proliferation, receptor tyrosine kinase-dependent signaling, and extracellular IGF-II protein accumulation were all reduced in the presence of IGF-IIR affinity. Inhibition of IGF-II signaling appeared to be the sole consequence of IGF-IIR affinity, as no cellular responses attributable to selective IGF-IIR binding by a reduced IGF-IR affinity IGF-II mutant could be detected. By operating as an IGF-II antagonist, the IGF-IIR has tumor suppressor-like properties, a suggestion consistent with reports of loss of heterozygosity at the IGF-IIR locus in a variety of human malignancies.
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PMID:Affinity for the insulin-like growth factor-II (IGF-II) receptor inhibits autocrine IGF-II activity in MCF-7 breast cancer cells. 883 57

Neutralization of insulin-like growth factor action by insulin-like growth factor binding protein-1 inhibits the in vitro growth of breast cancer cells. We performed this study to determine the pharmacokinetic profile of recombinant human IGFBP-1 (rhIGFBP-1) in athymic mice as a prelude to testing this protein in a human tumor xenograft model. After the subcutaneous injection of 1 mg, rhIGFBP-1 migrating at 29 kDa could be detected by ligand blotting and immunoblotting. Plasma concentrations of rhIGFBP-1 were quantified by immunoassay and demonstrated a half-life was 2.49 hours with the maximal concentration of 43.5 micrograms/mL occurring at 1 hour. The area under the concentration-time curve was 78.32 micrograms x hr/mL. Plasma clearance was 12.77 mL/hr and the mean residence time was 1.96 hours. rhIGFBP-1 was also detected in some tissues and was also cleared rapidly. These results show that high plasma and tissue levels of rhIGFBP-1 can be obtained after subcutaneous injection in athymic mice, however, the short half-life of the protein may limit its therapeutic use.
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PMID:Pharmacokinetic profile of recombination human insulin-like growth factor binding protein-1 in athymic mice. 888 72

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.
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PMID:Associations between insulin-like growth factors and their binding proteins and other prognostic indicators in breast cancer. 888 11

Women who have palpable breast cysts with intracystic Na/K > 3 may have a lower risk of developing breast cancer than those with intracystic Na/K < 3. In this study significantly higher concentrations of insulin-like growth factor-binding protein-3 (IGFBP-3), insulin-like growth factors I and II (IGF-I, IGF-II) and transforming growth factor-beta 2 (TGF-beta2) were found in the Na/K > 3 sub-group. No difference was found in transforming-growth factor-beta 1 (TGF-beta1) levels between the two sub-groups of breast cysts. A positive correlation was obtained for IGFBP-3 and TGF-beta1 in the Na/ K > 3 sub-group consistent with reports that TGF-beta1 may regulate the production of IGFBP-3. Equimolar amounts of total IGFs and IGFBP-3 in breast cyst fluid imply that most, if not all, of these IGFs are protein-bound. The significantly higher concentrations of TGF-beta2 in the Na/K > 3 sub-group may partly explain the lower risk of breast cancer in this group of women.
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PMID:Insulin-like growth factor binding protein-3 in breast cyst fluid: relationships with insulin-like growth factors I and II and transforming growth factor-beta 1 and 2. 901 3

The human insulin analogue ASPB10 has been reported to have increased affinity for the insulin receptor and to cause breast cancer in female rats. In the study reported here, we investigated whether ASPB10 has an increased mitogenic potency and induces a transformed phenotype in cultured human breast cells. In both MCF-10 cells (a non-malignant human breast line) and MCF-7 cells (a human breast cancer cell line), ASPB10 was approximately twofold more potent than insulin in competing for 125I-insulin binding but sevenfold to tenfold more potent than insulin in competing for 125I-insulin-like growth factor (IGF)-I binding. In addition, ASPB10 was twofold more potent than insulin in stimulating insulin receptor autophosphorylation but significantly more potent in stimulating IGF-I receptor autophosphorylation in both cell lines. Moreover, ASPB10 was approximately sevenfold more potent than insulin in stimulating the growth of MCF-10 and MCF-7 cells. This increased mitogenic effect of ASPB10 was significantly inhibited (but not abolished) when cells were cultured in the presence of alpha-IR3, a monoclonal antibody to the IGF-I receptor. ASPB10, but not insulin, caused phenotypic changes (focus formation) in MCF-10 cells. Neither agent caused colony formation in soft agar in MCF-10 cells, but ASPB10 was more potent than insulin in stimulating colony formation in MCF-7 cells. These observations indicate that in human breast cells, ASPB10 has enhanced mitogenic effects and induces phenotypic changes as a consequence of its activation of both insulin and IGF-I receptors.
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PMID:ASPB10 insulin induction of increased mitogenic responses and phenotypic changes in human breast epithelial cells: evidence for enhanced interactions with the insulin-like growth factor-I receptor. 902 9

Ligands for the type I insulin-like growth factor (IGF) receptor interact with oestrogens to control the proliferation of oestrogen responsive breast cancer cells. The aim of this study was to determine the involvement of ligands for the type I IGF receptor in the regulation of oestrogen receptor (OR) expression by oestrogens and antioestrogens in these cells. Oestrogen decreased OR mRNA levels in MCF-7 cells whereas it increased them in T47D, EFM-19 and ZR-75 cells. In MCF-7 cells, IGF-I and insulin lowered further OR expression in the presence of oestrogen. In the presence of IGF-I or insulin, the induction of progesterone receptor mRNA by oestradiol was considerably attenuated in MCF-7 cells, showing that the enhanced down-regulation of OR mRNA levels influenced the expression of oestrogen-regulated genes. The oestrogen agonist activity of the antioestrogens tamoxifen and ICI 182 780 for the down-regulation of OR expression in MCF-7 cells was modulated by type I IGF receptor ligands. Overall these experiments show that OR expression is differentially regulated by oestrogen in individual oestrogen-responsive breast cancer cell lines. Ligands for the type I IGF receptor can modulate regulation of OR expression by oestrogens and antioestrogens principally in cells in which oestrogens down-regulate OR expression.
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PMID:Insulin-like growth factors control the regulation of oestrogen and progesterone receptor expression by oestrogens. 914 76

In this study, we tested the hypothesis that insulin-like growth factor-1 (IGF-1) modulates apoptosis in human breast cancer cells, HBL100, induced by diverse chemotherapeutic drugs. IGF-1 increased cell survival of HBL100 cells treated with 5-fluorouracil (antimetabolite), methotrexate (antimetabolite), tamoxifen (antiestrogen/antiproliferative), or camptothecin (topoisomerase 1 inhibitor) and after serum withdrawal. Elevated cell survival was not due to an increase in cell proliferation by IGF-1, but rather to an inhibition of apoptosis. Evidence for death by apoptosis was supported by cellular morphology and DNA fragmentation. There were no changes observed in Bcl-2 protein or bax mRNA levels. Extracellular matrix (ECM) is known to influence the apoptotic response of cells; therefore, the antiapoptotic effect of IGF-1 on breast cancer cells was examined using different ECMs: laminin, collagen IV, or Matrigel. IGF-1 protected cells from apoptosis induced by methotrexate on all ECMs tested, providing the first evidence that IGF-1 protects against apoptosis in three-dimensional culture systems. These data provide the rationale to search for drugs that lower serum IGF-1 in an effort to improve the efficacy of chemotherapeutic drugs for the treatment of breast cancer.
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PMID:Insulin-like growth factor 1 (IGF-1) alters drug sensitivity of HBL100 human breast cancer cells by inhibition of apoptosis induced by diverse anticancer drugs. 920 78

We used enzymatic activity and immunochemical quantifications to analyse the expression and secretion of cathepsin D by human breast cancer cell lines of different invasive potentials (MCF-7/6, MCF-7/AZ, MDA-MB-231). This study does not directly prove that cathepsin D or procathepsin D is involved in human breast cancer cell invasion and metastasis but it shows that the proportion of procathepsin D (activity and antigen) secreted by the human breast cancer cell lines tested correlates with their invasive potential. In the estrogen receptor-positive MCF-7 subclones, this proportion is increased by estradiol only in the invasive MCF-7/6 variant. The cell content in procathepsin D is increased by estrogens to a greater extent in MCF-7/6 cells as compared to non-invasive MCF-7/AZ cells. Tamoxifen appears to be an estrogen agonist concerning cathepsin D regulation, whereas ICI 182,780 is a true antagonist. Our results suggest that synthesis and secretion of cathepsin D are regulated at two distinct levels and differentially affected by estrogens. Synthesis only seems to be affected in non-invasive MCF-7/AZ cells, whereas in invasive MCF-7/6 cells, both synthesis and the efficiency of secretion are increased by estrogens. Our results also confirm that the key site of regulation leading to lysosomal enzyme oversecretion is the Golgi apparatus insulin-like growth factor-II/mannose 6-phosphate receptor.
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PMID:Western immunoblotting and enzymatic activity analysis of cathepsin D in human breast cancer cell lines of different invasive potential. Regulation by 17beta-estradiol, tamoxifen and ICI 182,780. 921 23


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