The role of estrogen receptor in melanoma

The estrogen receptor (ER) belongs to the group of sex hormone receptors and binds the biologically active form of estrogen, 17beta-estradiol. Expression of ER in tumor tissue is a well-established prognostic marker in breast cancer. The role of ER has been extensively studied in several other types of human cancers. This report investigates the potential role of ER as a surrogate marker for predicting melanoma progression, response to therapy, and patient survival. In addition, the authors review what is known, so far, about ER signaling pathways and their potential role in carcinogenesis and progression of cutaneous melanoma. Possibilities and limitations of using ER as a therapeutic target in the treatment of melanoma is also discussed.     

Estrogen receptor beta in cancer: an attractive target for therapy

While it is well documented that the mitogenic actions of estrogens are critical in the development and progression of human breast and some gynecologic cancers, only latest data demonstrate a crucial involvement of estrogen-signaling in the carcinogenesis of non-classical estrogen target tissues, as colon, prostate, lung, skin, and brain. Only recently it has also been found out that the biological effects of estrogens are mediated by two distinct estrogen receptors (ERs), ERα and ERβ, and that their relative levels in a given cell are important determinants of response to estradiol and selective estrogen receptor modulators. Indeed, although ERα and ERβ have similar structure, they produce different effects, and there is currently increasing evidence that, for some tumors, an imbalanced ERβ expression might play a pivotal role in tumor development and progression. However, the prognostic value, the potential significance in predicting response to endocrine therapy, and, eventually, the utility of ERβ as a therapeutic target need to be assessed in large-scale and prospective clinical studies. This review examines the experimental and clinical evidences for a role of ERβ in carcinogenesis of classical and nonclassical estrogen target tissues. If anomalies of ERβ expression could be demonstrated to represent a critical step in the development and progression of some types of cancers, its re-expression by genetic engineering, as well as the use of targeted ERβ therapies would constitute new important therapeutic approaches.     

雌激素受体β与乳腺癌中关系的研究进展

目的探讨雌激素受体β(ERβ)与乳腺癌关系的研究进展.方法采用文献回顾分析方法,对ERβ的功能、分型,及其乳腺癌发生、发展、预后评估及内分泌治疗反应方面的可能作用加以综述.结果ERβ可能在乳腺癌发生中的作用、对预后及内分泌治疗反应方面具有重要作用.结论虽然ERβ研究结果不一致,但仍是一种新的乳腺癌预后评估指标.     

Increased plasticity of the stiffness of melanoma cells correlates with their acquisition of metastatic properties

The stiffness of tumor cells varies during cancer progression. In particular, metastatic carcinoma cells analyzed by Atomic Force Microscopy (AFM) appear softer than non-invasive and normal cells. Here we examined by AFM how the stiffness of melanoma cells varies during progression from non-invasive Radial Growth Phase (RGP) to invasive Vertical Growth Phase (VGP) and to metastatic tumors. We show that transformation of melanocytes to RGP and to VGP cells is characterized by decreased cell stiffness. However, further progression to metastatic melanoma is accompanied by increased cell stiffness and the acquisition of higher plasticity by tumor cells, which is manifested by their ability to greatly augment or reduce their stiffness in response to diverse adhesion conditions. We conclude that increased plasticity, rather than decreased stiffness as suggested for other tumor types, is a marker of melanoma malignancy. These findings advise caution about the potential use of AFM for melanoma diagnosis.From the Clinical EditorThis study investigates the changes to cellular stiffness in metastatic melanoma cells examined via atomic force microscopy. The results demonstrate that increased plasticity is a marker of melanoma malignancy, as opposed to decreased stiffness.     

Selective estrogen receptor-beta (SERM-beta) compounds modulate raphe nuclei tryptophan hydroxylase-1 (TPH-1) mRNA expression and cause antidepressant-like effects in the forced swim test

Estrogen acts through two molecularly distinct receptors termed estrogen receptor alpha (ERα) and estrogen receptor beta (ERβ) which bind estradiol with similar affinities and mediate the effects of estrogen throughout the body. ERα plays a major role in reproductive physiology and behavior, and mediates classic estrogen signaling in such tissues as the uterus, mammary gland, and skeleton. ERβ, however, modulates estrogen signaling in the ovary, the immune system, prostate, gastrointestinal tract, and hypothalamus, and there is some evidence that ERβ can regulate ERα activity. Moreover, ERβ knockout studies and receptor distribution analyses in the CNS suggest that this receptor may play a role in the modulation of mood and cognition. In recent years several ERβ-specific compounds (selective estrogen receptor beta modulators; SERM-beta) have become available, and research suggests potential utility of these compounds in menopausal symptom relief, breast cancer prevention, diseases that have an inflammatory component, osteoporosis, cardiovascular disease, and inflammatory bowel disease, as well as modulation of mood, and anxiety. Here we demonstrate an antidepressant-like effect obtained using two SERM-beta compounds, SERM-beta1 and SERM-beta2. These compounds exhibit full agonist activity at ERβ in a cell based estrogen response element (ERE) transactivation assay. SERM-beta1 and 2 are non-proliferative with respect to breast as determined using the MCF-7 breast cancer cell-based assay and non-proliferative in the uterus as determined by assessing the effects of SERM-beta compounds on immature rat uterine weight and murine uterine weight. In vivo SERM-beta1 and 2 are brain penetrant and display dose dependent efficacy in the murine dorsal raphe assays for induction of tryptophan hydroxylase mRNA and progesterone receptor protein. These compounds show activity in the murine forced swim test and promote hippocampal neurogenesis acutely in rats. Taken together these data suggest that ERβ may play an important role in modulating mood and the ERβ specific compounds described herein will be useful tools for probing the utility of an ERβ agonist for treating neuroendocrine-related mood disturbance and menopausal symptoms.     

Trastuzumab not for ductal carcinoma in situ?

Ductal carcinoma in situ (DCIS) is a preinvasive breast lesion accounting for approximately 30% of all newly detected breast cancers in the US. DCIS has been separated into two groups by architecture (comedo versus noncomedo) and nuclear grade. The expression of biological markers in DCIS, however, would reflect the true biologic potential of the lesion. Patients with estrogen receptor (ER)-negative, human epidermal growth factor-2 (HER-2)-positive DCIS pose a treatment challenge. They are not candidates for tamoxifen; trastuzumab has an undetermined role in DCIS. In this report, we present a case of a 45-year-old woman diagnosed with invasive breast cancer and ER-negative/HER-2-positive DCIS who developed recurrence and progression of DCIS as manifested by a new palpable mass while receiving trastuzumab as part of adjuvant treatment for invasive breast cancer. The potential clinical implications are discussed.     

凝血酶蛋白酶激活受体-1作为转移性黑色素瘤治疗潜在靶点的研究进展

黑色素瘤由于转移性强,成为皮肤癌中死亡率最高的恶性肿瘤之一,目前没有有效的治疗方法。凝血酶蛋白酶激活受体-1(PAR-1)在黑色素瘤的发病过程中起到重要作用,PAR-1通过激活肿瘤细胞黏附和侵袭以及新生血管因子生成促进黑色素瘤转移。PAR-1有望成为治疗转移性黑色素瘤药物新靶点。     

Fibroblasts contribute to melanoma tumor growth and drug resistance

The role of tumor-stromal interactions in progression is generally well accepted, but their role in initiation or treatment is less well understood. It is now generally agreed that, rather than consisting solely of malignant cells, tumors consist of a complex dynamic mixture of cancer cells, host fibroblasts, endothelial cells and immune cells that interact with each other and microenvironmental factors to drive tumor progression. We are particularly interested in stromal cells (for example fibroblasts) and stromal factors (for example fibronectin) as important players in tumor progression since they have also been implicated in drug resistance. Here we develop an integrated approach to understand the role of such stromal cells and factors in the growth and maintenance of tumors as well as their potential impact on treatment resistance, specifically in application to melanoma. Using a suite of experimental assays we show that melanoma cells can stimulate the recruitment of fibroblasts and activate them, resulting in melanoma cell growth by providing both structural (extracellular matrix proteins) and chemical support (growth factors). Motivated by these experimental results we construct a compartment model and use it to investigate the roles of both stromal activation and tumor aggressiveness in melanoma growth and progression. We utilize this model to investigate the role fibroblasts might play in melanoma treatment resistance and the clinically observed flare phenomenon that is seen when a patient, who appears resistant to a targeted drug, is removed from that treatment. Our model makes the unexpected prediction that targeted therapies may actually hasten tumor progression once resistance has occurred. If confirmed experimentally, this provocative prediction may bring important new insights into how drug resistance could be managed clinically.     

ER stress‐induced autophagy in melanoma

The activation of RAF‐MEK–extracellular signal‐regulated kinase (ERK) mitogen‐activated protein kinase cascade by v‐raf murine sarcoma viral oncogene homolog B1 (BRAF)^V600E mutation is a key alteration in melanoma. Although BRAF inhibitor (BRAFi) has achieved remarkable clinical success, the positive response to BRAFi is not sustainable, and the initial clinical benefit is eventually barred by the development of resistance to BRAFi. There is growing evidence to suggest that endoplasmic reticulum (ER) stress‐induced autophagy could be a potential pro‐survival mechanism that contributes to genesis of melanoma and to the resistance to BRAFi. ER stress‐induced autophagy is an evolutionarily conserved membrane process. By degrading and recycling proteins and organelles via the formation of autophagous vesicles and their fusion with lysosomes, the autophagy plays a key role in homeostasis as well as pathological processes. In this review, we examine the autophagy phenomenon in melanocytic nevus, primary and metastatic melanoma, and its significance in BRAFi‐resistant melanoma.     

17β-estradiol-linked nitro-L-arginine as simultaneous inducer of apoptosis in melanoma and tumor-angiogenic vascular endothelial cells

Aggressive melanoma is commonly associated with rapid angiogenic growth in tumor mass, tumor cells acquiring apoptosis resistance, inhibition of cellular differentiation etc. Designing a single anticancer molecule which will target all these factors simultaneously is challenging. In the pretext of inciting anticancer effect through inhibiting nitric oxide synthase (NOS) via estrogen receptors (ER) in ER-expressing skin cancer cells, we developed an estrogen-linked L-nitro-arginine molecule (ESAr) for inciting anticancer effect in melanoma cells. ESAr showed specific anticancer effect through diminishing aggressiveness and metastatic behavior in melanoma cells and tumor. In comparison, ESAr showed significantly higher antiproliferative effect than parent molecule L-nitroarginine methyl ester (L-NAME, a NOS inhibitor) through induction of prominent apoptosis in melanoma cells. ESAr-pretreated aggressive melanoma cells could not form tumor possibly because of transformation/differentiation into epithelial-type cells. Furthermore, its antiangiogenic effect was demonstrated through ESAr-induced antiproliferation in HUVEC cells and apoptosis-induction in tumor-associated vascular endothelial cells, thereby significantly restricting severe growth in melanoma tumor. The targeting moiety, estrogen, at the therapeutic concentration of ESAr has apparently no effect in tumor-growth reduction. Albeit, no specific NOS-inhibition was observed, but ESAr could simultaneously induce these three cancer-specific antiaggressiveness factors, which the parent molecule could not induce. Our data rationalize and establish a new use of estrogen as a ligand for potentially targeting multiple cellular factors for treating aggressive cancers.     

雌激素孕激素及受体在肝门部胆管癌中的表达

目的探讨雌、孕激素(ER、PR)及其受体在肝门部胆管癌的发生中的作用。方法应用放射免疫法测定42例肝门部胆管癌患者血中的雌、孕激素水平；应用免疫组织化学法，检测其组织中ER及PR表达水平。结果42例肝门部胆管癌患者中，雌、孕激素高于正常者分别占73．8％和69．0％，ER及PR阳性表达率分别为66．7％、和64．3％。与对照组相比，雌、孕激素水平及受体表达具有明显差异。结论肝门部胆管癌患者中，多数雌、孕激素水平高，ER及PR表达率高。雌、孕激素及受体可能在肝门部胆管癌发生和发展过程中起重要作用。     

Virtual screening of the estrogen receptor

Background: For > 30 years, the estrogen receptor (ER) has been the most important biomarker in breast cancer, principally because of its role in indicating the potential of patients to benefit from endocrine therapy. The search for modulators of ER (selective estrogen receptor modulators) through the use of computational methods such as virtual screening (VS) has redefined the area. Objective: We demonstrate how this receptor has become a key target in the computational (docking and scoring, pharmacophore) arena for algorithm development and validation. The use of quantitative structure–activity relationship for estimation of binding affinity to ER is also discussed, and finally all examples of lead identification through VS are exemplified using several VS campaigns carried out to identify environmental endocrine disruptors. Method: This review comprehensively details all current applications of virtual screening to the estrogen receptor and demonstrates how its use has pushed the boundaries of VS in general. Conclusion: The widespread application of the estrogen receptor to VS has allowed identification of numerous pitfalls within the process flow of VS such as library generation, correct validation procedures for docking/scoring functions, and inclusion of receptor flexibility.     

Estrogen receptors and human disease: an update

A myriad of physiological processes in mammals are influenced by estrogens and the estrogen receptors (ERs), ERα and ERβ. As we reviewed previously, given the widespread role for estrogen in normal human physiology, it is not surprising that estrogen is implicated in the development or progression of a number of diseases. In this review, we are giving a 5-year update of the literature regarding the influence of estrogens on a number of human cancers (breast, ovarian, colorectal, prostate, and endometrial), endometriosis, fibroids, and cardiovascular disease. A large number of sophisticated experimental studies have provided insights into human disease, but for this review, the literature citations were limited to articles published after our previous review (Deroo and Korach in J Clin Invest 116(3):561–570, 2006) and will focus in most cases on human data and clinical trials. We will describe the influence in which estrogen’s action, through one of or both of the ERs, mediates the aforementioned human disease states.     

热休克蛋白70与雌孕激素受体在男性乳腺良恶性病变中的表达

目的　为探讨热休克蛋白 70与雌、孕激素受体在男性乳腺增生和男性乳癌增殖中的作用及意义。方法　用免疫组织化学方法对 2 8例男性乳腺发育异常和 2例男性乳癌进行检测。结果　在 2 8例男性乳腺增生病变中 ,热休克蛋白 70阳性率为 70 .1% (2 0 / 2 8) ,雌、孕激素受体阳性率分别为 6 4.3%和 6 0 .7% (18/ 2 8和 17/ 2 8) ;2例男性乳癌三种染色均为阳性。结论　结果提示 ,热休克蛋白可作为导管上皮增生及癌细胞增殖的一个指标。雌、孕激素受体失衡与男性乳腺增生及男性乳癌的发生有关。     

Estrogen receptors as targets for drug development for breast cancer, osteoporosis and cardiovascular diseases

Estrogen receptors (ERs) are proteins that mediate the action of estradiol and a series of natural and synthetic chemicals that mimic the estradiol structure. Estrogenic action was initially attributed to a single type of ER, now known as ERalpha, but ERbeta was discovered in 1995. Tissue specific distribution and the intensity of expression of these proteins determine the first response of tissues to estrogenic compounds. Estrogens and ERs play a major role in the origin and progression of breast cancer, and antiestrogens that block ER function are useful for breast cancer prevention and treatment. Estrogen mimetics, however, do not fall into distinct categories of agonists and antagonists, since their action is regulated by tissue-specific expression of a number of auxiliary proteins called coactivators or corepressors. In addition, small molecules such as polyamines, fattyacids, and thioredoxin may modulate ER function. Estrogenic functions encompass multiple organ systems, including the reproductive, skeletal, cardiovascular, and nervous system. Estrogens are critical for bone remodeling and mineralization so that estrogen replacement therapy is proven to strengthen bone health in post-menopausal women. Ideally, selective blockade of ER function in breast epithelial cells should be accompanied by growth support on bone and cardiovascular systems. The details of estrogenic function in different organs are to be fully realized, in order to better utilize selective estrogen receptor modulators (SERMs) to fight not only breast cancer but also osteoporosis and cardiovascular diseases. Current research on SERMs points toward accomplishing this goal by exploiting ER as a versatile target against multiple diseases.     

Transgenerational and developmental exposure of Japanese medaka (Oryzias latipes) to ethinylestradiol results in endocrine and reproductive differences in the response to ethinylestradiol as adults.

17alpha-Ethinylestradiol (EE), a synthetic estrogen found in birth control pills, has been detected in the effluent of municipal wastewater treatment plants in several countries. Because EE was designed to be extremely potent at the estrogen receptor (ER), environmental exposure to low concentrations has the potential to disrupt the development of normal endocrine and reproductive function when exposure occurs during critical periods in development. Japanese medaka, Oryzias latipes, were used to evaluate the effect of exposure to EE during development on adult reproduction and endocrine function and the sensitivity of these animals to estrogen exposure as adults. To determine if the response to exogenous estrogen stimulation was diminished or sensitized, adults resulting from the developmental exposure groups were reexposed to EE at respectively higher concentrations. Hatchling exposure produced no changes in adult vitellogenin (VTG) content in the liver or circulating steroid concentrations, nor was reproduction affected. Reexposure of these adults inhibited reproduction, increased hepatic VTG and ER, and increased estrogen concentration measured in male plasma. Parental exposure produced permanent changes in hepatic content of ER and VTG in the adults resulting from exposure during gametogenesis and was related to a diminished response of males to subsequent estrogen exposure. The potential for this transgenerational exposure to decrease the responsiveness of males to EE is supported by comparing the concentration-response curves for hepatic VTG and ER in males exposed in ovo and as hatchlings. Our results indicate that the relationship between biomarkers and estrogen exposure will be altered by the timing and frequency of exposure.