Biological activity and binding of estradiol to SK-Mel 23 human melanoma cells

Sex and Gender Disparities in Melanoma

Worldwide, the total incidence of cutaneous melanoma is higher in men than in women, with some differences related to ethnicity and age and, above all, sex and gender. Differences exist in respect to the anatomic localization of melanoma, in that it is more frequent on the trunk in men and on the lower limbs in women. A debated issue is if-and to what extent-melanoma development can be attributed to gender-specific behaviors or to biologically intrinsic differences. In the search for factors responsible for the divergences, a pivotal role of sex hormones has been observed, although conflicting results indicate the involvement of other mechanisms. The presence on the X chromosome of numerous miRNAs and coding genes playing immunological roles represents another important factor, whose relevance can be even increased by the incomplete X chromosome random inactivation. Considering the known advantages of the female immune system, a different cancer immune surveillance efficacy was suggested to explain some sex disparities. Indeed, the complexity of this picture emerged when the recently developed immunotherapies unexpectedly showed better improvements in men than in women. Altogether, these data support the necessity of further studies, which consider enrolling a balanced number of men and women in clinical trials to better understand the differences and obtain actual gender-equitable healthcare.

Ethinylestradiol and Levonorgestrel as Active Agents in Normal Skin, and Pathological Conditions Induced by UVB Exposure: In Vitro and In Ovo Assessments

The link between melanoma development and the use of oral combined contraceptives is not fully elucidated, and the data concerning this issue are scarce and controversial. In the present study, we show that the components of oral contraceptives, ethinylestradiol (EE), levonorgestrel (LNG), and their combination (EE + LNG) ± UVB (ultraviolet B radiation) induced differential effects on healthy (human keratinocytes, fibroblasts, and primary epidermal melanocytes, and murine epidermis cells) and melanoma cells (human—A375 and murine—B164A5), as follows: (i) at low doses (1 µM), the hormones were devoid of significant toxicity on healthy cells, but in melanoma cells, they triggered cell death via apoptosis; (ii) higher doses (10 µM) were associated with cytotoxicity in all cells, the most affected being the melanoma cells; (iii) UVB irradiation proved to be toxic for all types of cells; (iv) UVB irradiation + hormonal stimulation led to a synergistic cytotoxicity in the case of human melanoma cells—A375 and improved viability rates of healthy and B164A5 cells. A weak irritant potential exerted by EE and EE + LNG (10 µM) was assessed by the means of a chick chorioallantoic membrane assay. Further studies are required to elucidate the hormones’ cell type-dependent antimelanoma effect and the role played by melanin in this context.

Melanopsin and rhodopsin mediate UVA-induced immediate pigment darkening: Unravelling the photosensitive system of the skin

The mammalian skin has a photosensitive system comprised by several opsins, including rhodopsin (OPN2) and melanopsin (OPN4). Recently, our group showed that UVA (4.4 kJ/m²) leads to immediate pigment darkening (IPD) in murine normal and malignant melanocytes. We show the role of OPN2 and OPN4 as UVA sensors: UVA-induced IPD was fully abolished when OPN4 was pharmacologically inhibited by AA9253 or when OPN2 and OPN4 were knocked down by siRNA in both cell lines. Our data, however, demonstrate that phospholipase C/protein kinase C pathway, a classical OPN4 pathway, is not involved in UVA-induced IPD in either cell line. Nonetheless, in both cell types we have shown that: a) intracellular calcium signal is necessary for UVA-induced IPD; b) the involvement of CaMK II, whose inhibition, abolished the UVA-induced IPD; c) the role of CAMK II/NOS/sGC/cGMP pathway in the process since inhibition of either NOS or sGC abolished the UVA-induced IPD. Taken altogether, we show that OPN2 and OPN4 participate in IPD induced by UVA in murine normal and malignant melanocytes through a conserved common pathway. Interestingly, upon knockdown of OPN2 or OPN4, the UVA-driven IPD is completely lost, which suggests that both opsins are required and cooperatively signal in murine both cell lines. The participation of OPN2 and OPN4 system in UVA radiation-induced response, if proven to take place in human skin, may represent an interesting pharmacological target for the treatment of depigmentary disorders and skin-related cancer.

Estrogen Receptor β in Melanoma: From Molecular Insights to Potential Clinical Utility

Cutaneous melanoma is an aggressive tumor; its incidence has been reported to increase fast in the past decades. Melanoma is a heterogeneous tumor, with most patients harboring mutations in the BRAF or NRAS oncogenes, leading to the overactivation of the MAPK/ERK and PI3K/Akt pathways. The current therapeutic approaches are based on therapies targeting mutated BRAF and the downstream pathway, and on monoclonal antibodies against the immune checkpoint blockade. However, treatment resistance and side effects are common events of these therapeutic strategies. Increasing evidence supports that melanoma is a hormone-related cancer. Melanoma incidence is higher in males than in females, and females have a significant survival advantage over men. Estrogens exert their effects through estrogen receptors (ERα and ERβ) that affect cancer growth in an opposite way: ERα is associated with a proliferative action and ERβ with an anticancer effect. ERβ is the predominant ER in melanoma, and its expression decreases in melanoma progression, supporting its role as a tumor suppressor. Thus, ERβ is now considered as an effective molecular target for melanoma treatment. 17β-estradiol was reported to inhibit melanoma cells proliferation; however, clinical trials did not provide the expected survival benefits. In vitro studies demonstrate that ERβ ligands inhibit the proliferation of melanoma cells harboring the NRAS (but not the BRAF) mutation, suggesting that ERβ activation might impair melanoma development through the inhibition of the PI3K/Akt pathway. These data suggest that ERβ agonists might be considered as an effective treatment strategy, in combination with MAPK inhibitors, for NRAS mutant melanomas. In an era of personalized medicine, pretreatment evaluation of the expression of ER isoforms together with the concurrent oncogenic mutations should be considered before selecting the most appropriate therapeutic intervention. Natural compounds that specifically bind to ERβ have been identified. These phytoestrogens decrease the proliferation of melanoma cells. Importantly, these effects are unrelated to the oncogenic mutations of melanomas, suggesting that, in addition to their ERβ activating function, these compounds might impair melanoma development through additional mechanisms. A better identification of the role of ERβ in melanoma development will help increase the therapeutic options for this aggressive pathology.

Treatment with 5-Aza-2'-Deoxycytidine Induces Expression of NY-ESO-1 and Facilitates Cytotoxic T Lymphocyte-Mediated Tumor Cell Killing

BACKGROUND

NY-ESO-1 belongs to the cancer/testis antigen (CTA) family and represents an attractive target for cancer immunotherapy. Its expression is induced in a variety of solid tumors via DNA demethylation of the promoter of CpG islands. However, NY-ESO-1 expression is usually very low or absent in some tumors such as breast cancer or multiple myeloma. Therefore, we established an optimized in vitro treatment protocol for up-regulation of NY-ESO-1 expression by tumor cells using the hypomethylating agent 5-aza-2'-deoxycytidine (DAC).

METHODOLOGY/PRINCIPAL FINDINGS

We demonstrated de novo induction of NY-ESO-1 in MCF7 breast cancer cells and significantly increased expression in U266 multiple myeloma cells. This effect was time- and dose-dependent with the highest expression of NY-ESO-1 mRNA achieved by the incubation of 10 μM DAC for 72 hours. NY-ESO-1 activation was also confirmed at the protein level as shown by Western blot, flow cytometry, and immunofluorescence staining. The detection and quantification of single NY-ESO-1 peptides presented at the tumor cell surface in the context of HLA-A*0201 molecules revealed an increase of 100% and 50% for MCF7 and U266 cells, respectively. Moreover, the enhanced expression of NY-ESO-1 derived peptides at the cell surface was accompanied by an increased specific lysis of MCF7 and U266 cells by HLA-A*0201/NY-ESO-1(157-165) peptide specific chimeric antigen receptor (CAR) CD8+ T cells. In addition, the killing activity of CAR T cells correlated with the secretion of higher IFN-gamma levels.

CONCLUSIONS/SIGNIFICANCE

These results indicate that NY-ESO-1 directed immunotherapy with specific CAR T cells might benefit from concomitant DAC treatment.

Associations between environmental factors and incidence of cutaneous melanoma. Review

BACKGROUND

Cutaneous melanoma is one of the most serious skin cancers. It is caused by neural crest-derived melanocytes - pigmented cells normally present in the epidermis and, sometimes, in the dermis.

METHODS

We performed a review of current knowledge on the risk factors of cutaneous melanoma. Relevant studies were identified using the PubMed, Science Direct, Medline, Scopus, Scholar Google and ISI Web of Knowledge databases.

RESULTS

Melanoma incurs a considerable public health burden owing to the worldwide dramatic rise in incidence since the mid-1960s. Ultraviolet radiation exposure is the predominant environmental risk factor. The role of geographical (latitude) and individual factors such as skin type, life style, vitamin D levels and antioxidant protection, sunburn, and exposure to other environmental factors possibly contributing to melanoma risk (such as cosmetics including sunscreen, photosensitising drugs, and exogenous hormones) are reviewed in this article. Recently, both rare high risk susceptibility genes and common polymorphic genes contributing to melanoma risk have been identified.

CONCLUSIONS

Cutaneous melanoma is a complex cancer with heterogeneous aetiology that continues to increase in incidence. Introduction of new biomarkers may help to elucidate the mechanism of pathogenesis and individual susceptibility to the disease, and make both prevention and treatment more effective.

Concentration of endogenous estrogens and estrogen metabolites in the NCI-60 human tumor cell lines

Background

Endogenous estrogens and estrogen metabolites play an important role in the pathogenesis and development of human breast, endometrial, and ovarian cancers. Increasing evidence also supports their involvement in the development of certain lung, colon and prostate cancers.

Methods

In this study we systemically surveyed endogenous estrogen and estrogen metabolite levels in each of the NCI-60 human tumor cell lines, which include human breast, central nerve system, colon, ovarian, prostate, kidney and non-small cell lung cancers, as well as melanomas and leukemia. The absolute abundances of these metabolites were measured using a liquid chromatography-tandem mass spectrometry method that has been previously utilized for biological fluids such as serum and urine.

Results

Endogenous estrogens and estrogen metabolites were found in all NCI-60 human tumor cell lines and some were substantially elevated and exceeded the levels found in well known estrogen-dependent and estrogen receptor-positive tumor cells such as MCF-7 and T-47D. While estrogens were expected to be present at high levels in cell lines representing the female reproductive system (that is, breast and ovarian), other cell lines, such as leukemia and colon, also contained very high levels of these steroid hormones. The leukemia cell line RMPI-8226 contained the highest levels of estrone (182.06 pg/10⁶ cells) and 17β-estradiol (753.45 pg/10⁶ cells). In comparison, the ovarian cancer cell line with the highest levels of these estrogens contained only 19.79 and 139.32 pg/10⁶ cells of estrone and 17β-estradiol, respectively. The highest levels of estrone and 17β-estradiol in breast cancer cell lines were only 8.45 and 87.37 pg/10⁶ cells in BT-549 and T-47D cells, respectively.

Conclusions

The data provided evidence for the presence of significant amounts of endogenous estrogens and estrogen metabolites in cell lines not commonly associated with these steroid hormones. This broad discovery of endogenous estrogens and estrogen metabolites in these cell lines suggest that several human tumors may be beneficially treated using endocrine therapy aimed at estrogen biosynthesis and estrogen-related signaling pathways.