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Query: UMLS:C0006142 (breast cancer)
 160,383 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Polyamines may be involved in hormone-dependent breast cancer cell proliferation. The antiestrogen 4-hydroxy-tamoxifen and the polyamine synthesis inhibitor alpha-difluoromethylornithine (DFMO) inhibited MCF-7 growth, and this effect was additive. Transforming growth factor beta (TGF-beta) levels were increased by both compounds; again the effect was additive. Exogenous putrescine antagonized DFMO but not the antiestrogen. However, exogenous TGF-beta did not inhibit cell growth. Secretion of insulin-like growth factor 1 (IGF-1) was not affected by DFMO-induced polyamine depletion but 4-hydroxytamoxifen increased IGF-1, which suggests an estradiol-like effect. Thus polyamines are involved in basal TGF-beta secretion but do not mediate antiestrogen-induced TGF-beta secretion. IGF-1 secretion by MCF-7 cells is not under polyamine control. The antiproliferative effects of 4-hydroxytamoxifen and DFMO cannot be accounted for by either suppression of IGF-1 secretion (a growth stimulatory factor) or stimulation of TGF-beta production (a growth inhibitory polypeptide).
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PMID:Interactions between growth factor secretion and polyamines in MCF-7 breast cancer cells. 214 49

Biological data support the development of clinical trials designed to evaluate the activity of somatostatin (SMS) analogues in advanced breast cancer (ABC). Although previous clinical trials have failed to show antitumor activity, various factors may have biased their results. In an attempt to improve our understanding of the role of SMS analogues in ABC, 10 patients with favourable prognostic factors and who had not been heavily pretreated for advanced disease were treated with lanreotide 30 mg i.m. fortnightly (depot formulation). Blood samples were periodically taken to evaluate the effect of the drug on growth hormone (GH) and insulin-like growth factor 1 (IGF-1) and to determine drug serum levels. Although the drug was well tolerated, no clinical activity was observed. Serum GH and IGF-1 levels were not properly suppressed over time and drug serum concentrations fluctuated widely. In conclusion, SMS analogues cannot be recommended even as palliative treatment of ABC. Further studies should be undertaken to investigate the effect of higher drug doses, given subcutaneously or by means of continuous infusion, in suppressing GH and IGF-1 serum levels.
Breast Cancer Res Treat 1995 Jun
PMID:Biological and clinical evaluation of lanreotide (BIM 23014), a somatostatin analogue, in the treatment of advanced breast cancer. A pilot study by the I.T.M.O. Group. Italian Trials in Medical Oncology. 757 88

Recent observations have shown that the pineal hormone melatonin (MLT) may modulate oestrogen receptor (ER) expression and inhibit breast cancer cell growth. On this basis, we have evaluated the biological and clinical effects of a concomitant MLT therapy in women with metastatic breast cancer who had progressed in response to tamoxifen (TMX) alone. The study included 14 patients with metastasis who did not respond (n = 3) to therapy with TMX alone or progressed after initial stable disease (SD) (n = 11). MLT was given orally at 20 mg day-1 in the evening, every day starting 7 days before TMX, which was given orally at 20 mg day-1 at noon. A partial response was achieved in 4/14 (28.5%) patients (median duration 8 months). The treatment was well tolerated in all cases, and no MLT-induced enhancement of TMX toxicity was seen; on the contrary, most patients experienced a relief of anxiety. Mean serum levels of insulin-like growth factor 1 (IGF-1), which is a growth factor for breast cancer, significantly decreased on therapy, and this decline was significantly higher in responders than in patients with SD or progression. This pilot phase II study would suggest that the concomitant administration of the pineal hormone MLT may induce objective tumour regressions in metastatic breast cancer patients refractory to TMX alone.
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PMID:Modulation of cancer endocrine therapy by melatonin: a phase II study of tamoxifen plus melatonin in metastatic breast cancer patients progressing under tamoxifen alone. 771 Sep 54

The isoflavonoid kievitone potently inhibited the proliferation of the oestrogen receptor (ER)-positive breast cancer cell lines MCF-7 and T47D and the ER-negative breast cancer cell line SKBR3 (IC50 values 5-18 microM). DNA synthesis of MCF-7 cells stimulated by insulin-like growth factor 1, insulin-like growth factor 2, basic fibroblast growth factor or transforming growth factor alpha was inhibited by similar concentrations of kievitone (IC50 values 1-3 microM). DNA synthesis stimulated by 17, beta-oestradiol was also inhibited (IC50 = 6 microM). Compared with kievitone, genistein was 3-9 fold weaker as an inhibitor of the proliferation of the breast cancer cell lines and of growth factor-stimulated DNA synthesis. However, genistein was about 5-fold more potent than kievitone as an inhibitor of solubilised epidermal growth factor (EGF) receptor kinase activity and EGF receptor autophosphorylation.
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PMID:Potent inhibition of breast cancer cell lines by the isoflavonoid kievitone: comparison with genistein. 779 75

Tamoxifen (TAM) is used primarily in the management of breast cancer, and it also has bone-sparing effects similar to estrogen. In breast cancer patients TAM may have a potential role in the prevention and management of osteoporosis. TAM therapy is associated with uterine hyperplasia, and medroxyprogesterone acetate (MPA) added to the regimen provides protection against this. Due to the potential combined use of MPA and TAM in the clinical setting, this study was conducted to assess whether MPA acted synergistically, dampened, or enhanced the TAM effect on bone. Seventy-five female rats (60 oophorectomized; Ox), were randomized into five groups and received either TAM (0.1 mg/kg.day) and/or MPA (0.3 mg/kg.day) therapy over 28 days as follows: 1) sham; 2) Ox; 3) Ox plus TAM; 4) Ox plus MPA; and 5) Ox plus TAM plus MPA. Blood was sampled on days 0, 14, and 28 for measurement of ionized calcium, PTH, 1,25-dihydroxyvitamin D, osteocalcin, and insulin-like growth factor 1. TAM-treated rats showed a reduction in body weight serum osteocalcin, PTH, and insulin-like growth factor 1. Histomorphometric analysis of the proximal tibia showed less cancellous bone volume in Ox rats, and the effect was attenuated by TAM. MPA alone had no significant effect on cancellous bone volume. All the bone formation parameters evaluated (bone formation rate, mineral apposition rate, percent calcein-labeled surface, and number of osteoblasts) were higher in Ox rats compared with sham-operated rats and were lower in TAM-treated rats compared with Ox rats. These parameters were not changed by MPA, alone or in combination with TAM. The number of osteoclasts was higher in Ox rats compared with sham-operated rats and was reduced by TAM. MPA therapy alone or in combination with TAM did not affect number of osteoclasts. These results suggest that MPA neither dampened nor enhanced the effect of TAM on bone.
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PMID:The effect of medroxyprogesterone acetate on bone metabolism in the oophorectomized, tamoxifen-treated rat. 783 4

Endothelin-1 (ET-1) levels are elevated in human breast tumours compared with normal and benign tissues, and in the presence of insulin-like growth factor 1 (IGF-I) ET-1 is a potent mitogen for human breast fibroblasts. In this study we have examined the ability of intact human breast cancer cell lines to process exogenously added big ET-1 (1-38) to the active mature ET-1 peptide by using a specific radioimmunometric assay. In both hormome-dependent (MCF-7, T47-D) and hormone-independent (MDA-MB-231) breast cancer cell lines the putative endothelin-converting enzyme (ECE) exhibited apparent Michaelis-Menten kinetics when converting added big ET-1 to ET-1. Both basal ET-1 production and exogenously added big ET-1 to ET-1 conversion were greatly reduced in all three cell lines in response to the metalloproteinase inhibitor phosphoramidon but were insensitive to other classes of protease inhibitors. Inhibition was also observed when cells were incubated in the presence of the divalent cation chelators 1,10-phenanthroline and EDTA. In MCF-7 cells the optimal pH for the ECE activity using a saponin cell permeabilisation procedure was found to residue within a narrow range of 6.2-7.26. Our results indicate that human breast cancer cells contain a neutral phosphoramidon-sensitive metalloproteinase which can process big ET-1 to ET-1. In the breast this conversion could contribute substantially to the local extracellular levels of this proposed paracrine breast fibroblast mitogen.
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PMID:Human breast cancer cells contain a phosphoramidon-sensitive metalloproteinase which can process exogenous big endothelin-1 to endothelin-1: a proposed mitogen for human breast fibroblasts. 788 Jul 21

In postmenopausal women oral ethinylestradiol causes a reduction in circulating insulin-like growth factor 1 (IGF-1) and an increase in serum growth hormone levels. There are no data on the effect of conjugated estrogens, the preparation most often used in estrogen replacement treatment (ERT), on these parameters. We evaluated serum IGF-1 and growth hormone levels, together with the levels of sex hormone binding globulin (SHBG), an indicator of estrogen hepatocellular action, before and after 6 months of ERT in two comparable groups of postmenopausal women. Sixteen women were treated with oral conjugated estrogens, 0.625 mg/day, and 14 with transdermal estradiol, 0.05 mg/day. In the women treated with oral conjugated estrogens, an increase in SHBG (p < 0.001), a decrease in IGF-1 (p < 0.001) and an increase in growth hormone (p < 0.05) serum levels were observed. No such effects were seen with the use of transdermal estradiol, devoid of hepatocellular effects. Undoubtedly, oral conjugated estrogens, 0.625 mg/day, through a hepatocellular effect, cause marked modifications in the IGF-1/growth hormone axis, which may have clinical relevance. For instance, the decreased IGF-1 level, together with the increased level of SHBG, might provide some explanation of the favorable epidemiological data on breast cancer risk in women receiving oral conjugated estrogens.
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PMID:Differential effects of oral conjugated estrogens and transdermal estradiol on insulin-like growth factor 1, growth hormone and sex hormone binding globulin serum levels. 814 34

Earlier onset of menarche and tallness in adult women are mainly confirmed as risk markers for breast cancer. Recent disparate case-control studies have reported abdominal-type obesity and higher circulating levels of insulin, testosterone and insulin-like growth factor 1, to be further risk markers for breast cancer. There is evidence that abdominal-type obesity is recognisable in girls even before puberty, and disparate studies have shown it to be correlated with earlier onset of menarche, insulin resistance leading to hyperinsulinaemia, and an abnormal sex steroid profile. The implications are that earlier onset of puberty in a subset of girls can lead to more prolonged exposure of developing breast tissue to an abnormal sex steroid profile and also to a higher circulating level of insulin. It is postulated that these metabolic/endocrine concomitants of abdominal-type obesity could play a role in promoting mammary carcinogenesis at a young age, particularly if genetic predisposition is present.
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PMID:Does early physical maturity influence breast cancer risk? 820 71

Localization of growth factors such as transforming growth factor alpha (TGF-alpha) and beta1 (TGF-beta1), insulin-like growth factor 1 (IGF-1), and epidermal growth factor receptor (EGFR) in breast cancer tissue is controversial. We immunohistochemically investigated expression patterns of these growth factors and EGFR along with estrogen receptor (ER) status in 36 breast carcinomas (21 invasive ductal, 11 invasive lobular, 4 noninvasive ductal) and compared the results with those found in 10 fibroadenomas. Twenty-four of 36 carcinomas and all of the 10 fibroadenomas showed positivity for ER. TGF-alpha was immunoreactive in all of the carcinomas and fibroadenomas. TGF-beta1 was negative in all of the invasive ductal carcinomas and positive in all of the fibroadenomas and in five lobular carcinomas. EGFR was regularly expressed preferentially in the myoepithelial cells of mammary ducts in the fibroadenomas and in nontumorous glands. Six of the 36 carcinomas were positive for EGFR. Those tumors were negative for ER (P < .001). There was IGF-1 expression in all of the cases of carcinoma and fibroadenoma. We conclude that TGF-alpha is expressed abundantly in invasive and intraductal breast carcinomas and in fibroadenomas. EGFR expression significantly correlates with negative ER status in breast carcinoma. In breast carcinoma, IGF-1 is broadly expressed by the tumor as well as by stromal cells and might act as a growth stimulator in endocrine, paracrine, and autocrine manners.
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PMID:Immunohistochemical study of TGF-alpha, TGF-beta1, EGFR, and IGF-1 expression in human breast carcinoma. 934 75

The insulin-like growth factor binding proteins (IGFBPs) are a family of seven structurally homologous proteins that bind insulin-like growth factor 1 (IGF-I) and IGF-II with high affinity, thereby modu-lating the actions of IGFs. Several lines of recent evidence from various cell systems have suggested that IGFBPs, especially IGFBP-3, may play more active, IGF-independent, roles in growth regulation of cancer cells. In support of this hypothesis, the author has recently shown that IGFBP-3 binds specifically and with high affinity to the surface of various cell types and directly inhibits monolayer growth of these cells in an IGF-independent manner, presumably by specific interaction with cell membrane proteins that function as an IGFBP-3 receptor. The author's current studies demonstrate that a new class of IGFBP, IGFBP-7, constitutes a low affinity member of the IGFBP family, but primarily functions as a modulator of cell growth in an IGF-independent manner, similar to the action observed with IGFBP-3 in breast cancer cells. The author's studies on the mechanisms of action of the low affinity IGFBPs will provide insight into the IGF-independent actions of the classical high affinity IGFBPs and their impact on cancer cell growth.
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PMID:IGFBPs and neoplastic models. New concepts for roles of IGFBPs in regulation of cancer cell growth. 944 45


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