Silencing of estrogen receptor β promotes the invasion and migration of osteosarcoma cells through activating Wnt signaling pathway

Multi-Anticancer Activities of Phytoestrogens in Human Osteosarcoma

Phytoestrogens are plant-derived bioactive compounds with estrogen-like properties. Their potential health benefits, especially in cancer prevention and treatment, have been a subject of considerable research in the past decade. Phytoestrogens exert their effects, at least in part, through interactions with estrogen receptors (ERs), mimicking or inhibiting the actions of natural estrogens. Recently, there has been growing interest in exploring the impact of phytoestrogens on osteosarcoma (OS), a type of bone malignancy that primarily affects children and young adults and is currently presenting limited treatment options. Considering the critical role of the estrogen/ERs axis in bone development and growth, the modulation of ERs has emerged as a highly promising approach in the treatment of OS. This review provides an extensive overview of current literature on the effects of phytoestrogens on human OS models. It delves into the multiple mechanisms through which these molecules regulate the cell cycle, apoptosis, and key pathways implicated in the growth and progression of OS, including ER signaling. Moreover, potential interactions between phytoestrogens and conventional chemotherapy agents commonly used in OS treatment will be examined. Understanding the impact of these compounds in OS holds great promise for developing novel therapeutic approaches that can augment current OS treatment modalities.

Missing link between tissue specific expressing pattern of ERβ and the clinical manifestations in LGBLEL

Purpose

Lacrimal gland benign lymphoepithelial lesion (LGBLEL) is an IgG4-related disease of unknown etiology with a risk for malignant transformation. Estrogen is considered to be related to LGBLEL onset.

Methods

Seventy-eight LGBLEL and 13 control clinical samples were collected and studied to determine the relationship between estrogen and its receptors and LGBLEL development.

Results

The serological analysis revealed no significant differences in the levels of three estrogens be-tween the LGBLEL and control groups. However, immunohistochemical analyses indicated that the expression levels of ERβ and its downstream receptor RERG were relatively lower in LGBLEL samples than in control samples, with higher expression in the lacrimal gland and lower expression in the lymphocyte infiltration region. However, low expression of ERα was detected. The transcriptome sequence analysis revealed upregulated genes associated with LGBLEL enriched in lymphocyte proliferation and activation function; downregulated genes were enriched in epithelial and vascular proliferation functions. The key genes and gene networks were further analyzed. Interactions between B cells and epithelial cells were analyzed due to the identified involvement of leukocyte subsets and epithelial cells. B cell proliferation was found to potentially contribute to lacrimal gland apoptosis.

Conclusion

Therefore, the tissue-heterogeneous expression pattern of ERβ is potentially related to the clinical manifestations and progression of LGBLEL, although further investigations are required to confirm this finding.

Extracellular Acidosis Differentially Regulates Estrogen Receptor β-Dependent EMT Reprogramming in Female and Male Melanoma Cells

Clinical outcomes of melanoma patients pointed out a gender disparity that supports a correlation between sex hormone activity on estrogen receptors (ER) and melanoma development and progression. Here, we found that the epithelial-to-mesenchymal transition (EMT) of melanoma cells induced by extracellular acidosis, which is a crucial hallmark of solid cancers, correlates with the expression of ERβ, the most representative ER on melanoma cells. Extracellular acidosis induces an enhanced expression of ERβ in female cells and EMT markers remain unchanged, while extracellular acidosis did not induce the expression of ERβ in male cells and EMT was strongly promoted. An inverse relationship between ERβ expression and EMT markers in melanoma cells of different sex exposed to extracellular acidosis was revealed by two different technical approaches: florescence-activated cell sorting of high ERβ expressing cell subpopulations and ERβ receptor silencing. Finally, we found that ERβ regulates EMT through NF-κB activation. These results demonstrate that extracellular acidosis drives a differential ERβ regulation in male and female melanoma cells and that this gender disparity might open new perspectives for personalized therapeutic approaches.

CKB affects human osteosarcoma progression by regulating the p53 pathway

This study aimed to explore the role of the creatine kinase B (CKB) gene in the development of human osteosarcoma (OS). Western blotting and qRT-PCR were performed to detect CKB expression in tissues and cells. CCK-8, colony formation, flow cytometry, Transwell, and cell scratch assays were performed to detect OS cell viability, proliferation, apoptosis, invasion, and migration. Gene set enrichment analysis (GSEA) was used to conduct signal pathway enrichment. CKB expression was higher in OS tissues and cells than that in normal tissues and cells. Silencing CKB expression reduced cell proliferation, migration, and invasion, and improved cell apoptosis in HOS cells, while overexpressing CKB increased cell proliferation, migration, and invasion, and decreased apoptosis in U2-OS cells. GSEA showed that CKB affected the p53 signaling pathway. Overexpression of CKB inhibited the protein expression of p53, p21, and Bax and promoted the expression of Bcl-2 and MDM2 in U2-OS cells. Conversely, silencing CKB promoted the protein expression of p53, p21, and Bax, and inhibited the expression of Bcl-2 and MDM2 in HOS cells. Silencing p53 could reverse the effect of the silencing CKB in HOS cells, and overexpressing p53 could reverse the effect of overexpressing CKB in U2-OS cells. Taken together, CKB affects the development of OS by regulating the activity of the p53 signaling pathway.

Diosmetin inhibits cell proliferation and promotes apoptosis through STAT3/c-Myc signaling pathway in human osteosarcoma cells

BACKGROUND

Diosmetin is a bioflavonoid compound naturally abundant in citrus fruits. It is found to perform a variety of activities, while its antitumor property in osteosarcoma, a malignant tumor with unmet clinical treatment, remained unknown.

METHODS

Colony formation assay, cell cycle analysis and apoptosis analysis were conducted respectively to observe the effect of diosmetin on cell proliferation and apoptosis in human osteosarcoma cells. Western blot and immunoprecipitation were used to detect the expression of apoptotic molecules and activation of STAT3/c-Myc pathway in Saos-2 and U2SO cells.

RESULTS

Diosmetin significantly inhibited cell proliferation, induced cell cycle arrest at G2/M phase and promoted cell apoptosis in both Saos-2 and U2SO cells. Moreover, Diosmetin downregulated the expression of anti-apoptotic protein Bcl-xL while upregulated the levels of pro-apoptotic proteins including cleaved Caspase-3, cleaved-PARP and Bax. Furthermore, diosmetin dose-dependently inhibited STAT3 phosphorylation, reduced the expression of its downstream protein c-Myc and impeded the interaction between STAT3 molecules.

CONCLUSIONS

These results suggest that diosmetin exerts anti-osteosarcoma effects by suppressing cell proliferation and inducing apoptosis via inhibiting the activation of STAT3/c-Myc signaling pathway, which provide the possibility for diosmetin to be a chemotherapeutic candidate for osteosarcoma.

17β-estradiol promotes angiogenesis through non-genomic activation of Smad1 signaling in endometriosis

17β-estradiol (E2) plays a key role in endometriosis through regulation of angiogenesis. Smad1 has been reported to be up-regulated in patients with endometriosis. However, the role of Smad1 in E2-mediated angiogenesis during the development of endometriosis remains to be determined. This study aimed to explore the role of Smad1 in E2-mediated angiogenesis during endometriosis and its underlying mechanisms. Immunofluorescence staining and Western blotting were performed to examine the expression of p-Smad1 in ectopic and control endometrium. Western blotting was used to examine activation of Smad1 signaling in NMECs, EMECs and HUVECs. Tube formation assay was performed to examine the effect of E2 on angiogenesis. Cell proliferation and migration was determined using in real-time by xCELLigence RTCA DP instrument. We found that the expression of p-Smad1 was significantly up-regulated in ectopic endometrium and ectopic intima microvascular endothelial cells. E2 non-genomically stimulated phosphorylation of Smad1 in HUVECs. c-Src and p44/42 MAPK(ERK1/2) signaling pathways are required for E2's induction on Smad1 phosphorylation. Moreover, caveolae is involved in E2-induced Smad1 phosphorylation in vascular endothelial cells. E2 promoted tube formation of vascular endothelial cells through c-Src/ERK1/2/Smad1 signaling pathway. Knockdown of Smad1 expression attenuated E2-induced proliferation and migration of HUVECs. In conclusion, E2 promotes proliferation, migration and tube formation of HUVECs through c-Src/ERK1/2/Smad1 signaling pathway. Our data shed new lights on the mechanisms through which E2 contributes to endometriosis, and may provide novel strategies to treat endometriosis.

Estrogen receptor-β signaling induces cisplatin resistance in bladder cancer

The efficacy of cisplatin-based chemotherapy in patients with bladder cancer is often limited due to the development of therapeutic resistance. Our recent findings in bladder cancer suggested that activation of prostaglandin receptors (e.g. EP2, EP4) or cyclooxygenase (COX)-2 induced cisplatin resistance. Meanwhile, emerging evidence indicates the involvement of estrogen receptor-β (ERβ) signals in urothelial cancer progression. In this study, we aimed to investigate whether ERβ activity was associated with cisplatin sensitivity in bladder cancer. Immunohistochemistry in muscle-invasive bladder cancer specimens from 55 patients who had subsequently received at least 3 cycles of cisplatin + gemcitabine neoadjuvant chemotherapy showed that ERβ was positive in 38% of responders vs. 71% of non-responders (P = 0.016), including 42% of male responders vs. 65% of male non-responders (P = 0.142) and 20% of female responders vs. 100% of female non-responders (P = 0.048). Then, cisplatin cytotoxicity was compared in human bladder cancer cell lines. Control sublines endogenously expressing ERβ were significantly more resistant to cisplatin treatment at its pharmacological concentrations, compared with ERβ knockdown sublines via short hairpin RNA virus infection. An ER modulator tamoxifen increased sensitivity to cisplatin in ERα-negative/ERβ-positive cell lines, while, in an estrogen-depleted condition, 17β-estradiol reduced it. Additionally, western blot showed considerable elevation in ERβ expression in cisplatin-resistant bladder cancer sublines, compared with respective controls. Moreover, treatment with tamoxifen or a COX-2 inhibitor celecoxib increased cisplatin sensitivity even in resistant cells, while COX-2/EP2/EP4 inhibitor treatment resulted in reduced expression of ERβ. The expression and activity of β-catenin known to involve cisplatin resistance was also up-regulated in cisplatin-resistant cells, which was further induced by 17β-estradiol treatment. The present results suggest that estrogen-mediated ERβ signaling plays an important role in modulating cisplatin sensitivity in bladder cancer cells. Targeting ERβ during chemotherapy may thus be a useful strategy to overcome cisplatin resistance especially in female patients with ERβ-positive bladder cancer.