Mechanism of action of a tyrphostin, 3,4-dihydroxy-α-cyanothiocinnamamide, in breast cancer cell growth inhibition involves the suppression of cyclin B1 and the functional activity of cyclin B1/p34cdc2 complex

Tyrphostins are a group of compounds specifically targeted for the inhibition of tyrosine phosphorylation in signal transduction pathways. We studied the effects of a tyrphostin, 3,4-dihydroxy--cyanothiocinnamamide (tyrphostin-47), on hormone-responsive MCF-7 and hormone-unresponsive MCF-7-5C cell growth by DNA analysis for a period of 10 days. The growth of both cell lines was inhibited by this drug at 50 and 100 µM concentrations. Flow cytometric analysis showed that tyrphostin treatment caused a significant delay in the progression of MCF-7 cells through Gl and S phases of the cell cycle. The level of cyclin B1, a component of the mitosis promoting factor (MPF), was reduced by 90% in the presence of 100 µM tyrphostin. The other component of MPF, p34cdc2 kinase, was not affected; however, its functional activity was dramatically reduced, as determined by histone H1 phosphorylation assay. In contrast, G1 cyclins (D1 and E) and tyrosine kinase activity were not markedly affected by tyrphostin-47, as determined by Western immunoblot detection with specific antibodies. Our results suggest that a possible mechanism of tyrphostin action in breast cancer cells might involve the suppression of cyclin B1 and inhibition of the functional activity of cyclin B1/p34cdc2 complex. Our data indicate that the cell cycle machinery might be a target for developing novel drugs for breast cancer.     

自然排卵与注射人绒毛膜促性腺激素促排卵时阴道脱落细胞雌、孕激素受体的研究

目的：研究排卵期阴道脱落细胞的雌、孕激素受体。方法：自然排卵妇女、注射人绒毛膜促性腺激素（ｈｕｍａｎ ｃｈｏｒｉｏｎｉｃ ｇｏｎａｄｏｔｒｏｐｉｎ,ｈＣＧ）促排卵妇女排卵期阴道脱落细胞,应用免疫组织化学ＡＢＣ 法和图像分析技术进行雌激素受体（ｅｓｔｒｏｇｅｎｒｅｃｅｐｔｏｒ,ＥＲ） 和孕激素受体（ｐｒｏｇｅｓｔｅｒｏｎｅｒｅｃｅｐｔｏｒ,ＰＲ）的定位和定量研究。结果：两组组内排卵前、后阴道脱落细胞ＥＲ比较均无差异;注射ｈＣＧ 后阴道脱落细胞的ＥＲ在排卵前和排卵后均较自然排卵组有明显增高;自然排卵组ＰＲ在排卵后较之排卵前明显升高。结论：排卵前后阴道上皮细胞ＥＲ 无明显变化;ｈＣＧ可提高阴道上皮细胞ＥＲ 水平;排卵后阴道上皮细胞ＰＲ增加。     

雌激素受体与代谢型谷氨酸受体在延髓和脊髓的分布与共存

采用免疫细胞化学双重标记方法研究了雌性大鼠延髓和脊髓内雌激素受体（ＥＲ）和代谢型谷氨酸受体１亚型（ｍＧｌｕＲ１）的分布与共存,以探讨在受体水平神经与内分泌的相互关系。结果发现：链霉亲和素ＡＢＣ法显示ＥＲ免疫反应产物呈棕色,ｍＧｌｕＲ１免疫反应产物呈蓝黑色。ＥＲ和ｍＧｌｕＲ１在脊髓和延髓有广泛的分布：在脊髓的颈、胸、腰段,ＥＲ分布于腹角、背角和侧角;ｍＧｌｕＲ１的分布与ＥＲ相似,但以腹角和背角较为丰富。在延髓,ＥＲ分布于舌下神经核、迷走神经背核、三叉神经脊束核、孤束核和网状结构;ｍＧｌｕＲ１的分布与ＥＲ相似,但在数量上有差别。此外,在延髓和脊髓ＥＲ和ｍＧｌｕＲ１广泛共存于许多神经细胞内,即存在着双标细胞。结果提示：雌激素和谷氨酸可通过共存于同一神经细胞的受体,进而在信使、基因和转录水平相互作用,调节神经细胞的机能活动     

绝经前后妇女骨密度测定

目的研究妇女绝经后骨质疏松与雌激素的关系。方法收集了２５５例年龄在３２～７３岁之间的绝经前后的妇女。分成４组：月经正常、月经紊乱、自然绝经和人工绝经（双侧卵巢切除术）。用双能Ｘ线骨密度测定仪进行测量。结果妇女月经紊乱后,骨密度就明显下降,而绝经后的５年内显著下降。手术切除卵巢后,５年内骨密度也显著下降。结论绝经前切除卵巢或过早的闭经易导致骨质疏松,即妇女绝经后骨质疏松与雌激素下降有显著关系（Ｐ＜０．００１）。     

Exercice physique, carence estrogénique, monoxyde d'azote et remodelage osseux

Summary

Objectives

The aim of this paper is to emphasize the possible relationships established between estrogens and physical exercise and concerning bone metabolism. Nitric oxide (NO) might play an important role in such relationships.

Topics

Cellular metabolism of NO, as well as NO effects upon osteoblasts and osteoclasts have been summarized. Several studies indicate that NO deficiency might be implicated in various vascular diseases observed in post-menopausal women. Other works also indicate that NO deficiency induced by cessation of ovarian activity might be responsible for osteopenia associated with this condition. Thus, decreased production of NO would be responsible both for post-menopausal osteoporosis as well as for osteopenia sometimes observed in amenorrheic athletes. Moreover osteoblastic response to mechanical stimulation might implicate estrogenic receptor(s). The role of these receptors in the regulation of NO synthesis is still unknown.     

The significance ofheregulin in breast cancer tumor progression and drug resistance

Summary TheerbB-2 receptor plays an important role in the prognosis of breast cancer and is expressed at high levels in nearly 30% of tumors in breast cancer patients. While evidence accumulates to support the relationship betweenerbB-2 overexpression and poor overall survival in human breast cancer, understanding of the biological consequence(s) oferbB-2 overexpression remains elusive. The discovery ofheregulin has allowed us to identify a number of related but distinct biological endpoints which appear responsive to signal transduction through theerbB-2/4 receptor. These endpoints of growth, invasiveness, and differentiation have clear implications for the emergence, maintenance, and/or control of malignancy, and represent established endpoints in the assessment of malignant progression in human breast cancer. Preliminary studiesin vitro have shown thatheregulin induces a biphasic growth effect on cells witherbB-2 overexpression. Interestingly, we observed that expression ofheregulin correlates with a more aggressive/invasive, vimentin-positive phenotype in breast cancer cells lines. Therefore, we have postulated thatheregulin is involved in breast cancer tumor progression. We have shown thatheregulin inducesin vitro chemoinvasion and chemotaxis of breast cancer cells as well as growth in an anchorage dependent and independent manner. Interestingly, aheregulin neutralizing antibody inhibits chemotaxis and results in cell growth inhibition and blockade of the invasive phenotype. Strikingly, genetically engineered cells which constitutively expressheregulin demonstrate critical phenotypic changes that are associated with a more aggressive phenotype. Specifically, these cells are no longer dependent on estrogen for growth and are resistant to tamoxifenin vitro andin vivo, and moreover these cells metastasize to lymph nodes in athymic nude mice. These tumors appear to have lostbcl-2 expression as compared with the control tumors. In addition, presumably by activation/regulation of topoisomerase II, theheregulin-transfected cells become exquisitely sensitive to doxorubicin and VP-16. Clearly, mechanistic aspects of theerbB-2/4 andheregulin interaction need to be understood from a therapeutic standpoint which could provide additional insights into synergistic treatments for certain patients, or improve treatment regimens for a large number of women. The study ofheregulin and its co-expression witherbB-2/4 receptor and the assessment of its involvement in the progression from the in situ stage of breast tumors to the invasive one will additionally increase the relevance ofheregulin as a prognostic/diagnostic factor. We believe that our studies provide new insights into breast cancer diagnosis, prognosis, and treatment.Presented at the symposium "New Approaches in the Therapy of Breast Cancer", Georgetown University Medical Center, Washington DC, October 1994, generously supported by an education grant from Bristol-Myers Squibb.     

Quality control of estrogen receptor assays in the Netherlands

Summary Lyophilized receptor-positive tissue powders and cytosols, prepared from calf uterus and human breast tumor tissue, are used to assess the validity of routine dextran-coated charcoal estrogen receptor assays. Since 1978 lyophilized reference preparations have been analyzed twice yearly by 18 laboratories in the Netherlands. During 8 consecutive trials 20 different lyophilized samples were studied. The inter-laboratory variability of estrogen receptor results decreased with time. Most laboratories found receptor values around the median value of all groups together, though some participants consistently reported estrogen receptor values that were higher or lower than the median. The variability of estrogen receptor results between labs seemed to be associated with cytosol dilution, determination of non-specific binding, concentration and volume of dextrancoated charcoal, and the use of single dose assays or Scatchard analysis. The agreement on the presence or absence of estrogen receptors was more than 98% for lyophilized reference samples with high receptor content. For samples with low receptor content 85% agreement was observed, while 12% of the assays performed on receptor-negative material were reported to be estrogen receptor-positive. The use of the same protein determination (Coomassie Brilliant Blue) and human serum albumin standard has decreased the interlaboratory variation coefficient of the protein results to 7.5%. Address for reprnts: A. Koenders, Dept. of Experimental and Chemical Endocrinology, St. Radboud Hospital, Geert Grooteplein Z 8, 6500 HB Nijmegen, the Netherlands List of participating laboratories and institutions: Hospital de Lichtenberg, Amersfoort; Antoni van Leeuwenhoek Hospital, Amsterdam; Foundation Medical Laboratories, Breda; Foundation of Cooperative Hospitals Delft (SSDZ), Delft; Catharina Hospital, Eindhoven; Hospital de Stadsmaten and Ziekenzorg, Enschede; Academic Hospital, Groningen; The Wever Hospital, Heerlen; Laboratory of Public Health, Leeuwarden; Department of Pathological Chemistry, Academic Hospital, Leiden; Department of Experimental and Chemical Endocrinology, Sint Radboud Hospital, Nijmegen; Scientific Development Group Organon International B.V., Oss; Department of Biochemistry II, Erasmus University Rotterdam, Rotterdam; Rotterdam Radio-Therapeutic Institute/ Dr Daniel den Hoed Clinic, Rotterdam; Institute of Oncology Dr Bernard Verbeeten, Tilburg; Department of Endocrinology, Academic Hospital, Utrecht; Laboratory for Nuclear Medicine Voorburg, Vught; Sophia Hospital, Zwolle.     

Hormone receptors and obesity in Japanese women with breast cancer

Summary An association between hormone receptors in primary breast cancer and obesity determined prior to mastectomy was investigated in 128 Japanese women. The following criteria for obesity were used: (1) weight 60 kg (132 lbs), (2) weight kg/height cm–105 1.3, (3) weight lbs/height in 2.30, (4) body surface area 1.56 m². In view of the 4 criteria, tumor estrogen receptor (ER) values 4 fmol/mg were observed in obese patients more often than in nonobese patients, though the difference was not statistically significant. The same tendency was observed in the postmenopausal subgroup, 62 patients, especially in the 36 patients more than 5 years beyond menopause. However, there was still no statistical difference between obese and nonobese patients because the number of subjects was small. The same tendency was observed in the case of progesterone receptor (PgR) (6 fmol/mg) as observed in the case of ER. Address for reprints: Dr. Keijiro Kuno, Department of Surgery, Cancer Institute Hospital, 1-37-1 Kami-Ikebukuro, Toshima-ku, Tokyo, Japan 170     

选择性雌激素受体调节剂的作用机制研究近况

选择性雌激素受体调节剂(SERM)在不同的靶组织可以表现为雌激素激动剂和(或)拮抗剂，本文综述了近年来关于SERM结构、ER亚型、共调节子、靶启动子、细胞亚型、细胞内信号通路、雌激素受体相关受体等对SERM组织选择性的影响的研究状况。     

雌激素干预影响腹腔脂肪积聚的实验研究

目的研究雌激素干预对雌性C57BL/6J小鼠腹腔脂肪代谢的影响.方法采用卵巢切除法造成雌激素缺乏模型,以及在动情周期正常和围绝经期的小鼠中,给以雌激素干预,观察腹腔脂肪重量的变化.3 mon 龄小鼠随机分为正常组,卵巢切除组,给雌激素 15 d 组和给雌激素 60 d 组,每组10只.小鼠摘除卵巢后饲养至 7 mon 龄处死.5和 10 mon 龄小鼠分为正常组,动情周期正常+雌激素 60 d组,围绝经期组和围绝经期+雌激素 60 d 组,每组10只,分别饲养至7和 12 mon 龄处死,检测腹腔脂肪重量.各组小鼠于处死前15和 60 d 分别皮下埋植控释雌激素(17β-雌二醇)药丸(0.18 mg/丸).结果卵巢切除组腹腔脂肪重量明显增加(P<0.05);给雌激素 15 d 组腹腔脂肪重量减轻(P＜0.05);给雌激素 60 d 组腹腔脂肪重量有明显减轻,与正常组比较无显著性差别(P>0.05).动情周期正常+雌激素组和围绝经期+雌激素组的小鼠,其腹腔脂肪重量的变化无差别.结论卵巢切除明显影响小鼠的脂肪代谢导致腹腔脂肪积聚,而雌激素干预,特别是长期应用,可以明显减少小鼠的腹腔脂肪积聚.外源性雌激素干预在动情周期正常和围绝经期对小鼠腹腔脂肪没有明显的影响.