GPER1 and microRNA: Two Players in Breast Cancer Progression

The GPR30 Receptor Is Involved in IL-6-Induced Metastatic Properties of MCF-7 Luminal Breast Cancer Cells

Luminal breast cancer has a high incidence worldwide and poses a severe health threat. Estrogen receptor alpha (ER-α) is activated by 17β-estradiol (E2), and its overexpression promotes cancerous characteristics. Luminal breast cancer is an epithelial type; however, the cytokine IL-6, secreted by cells within the tumor microenvironment, stimulates the epithelial-to-mesenchymal transition (EMT) and promotes metastasis. Also, IL-6 decreases ER-α levels, favoring the tamoxifen (TMX) resistance development. However, genes under E2 regulation continue to be expressed even though this receptor is absent. GPR30 is an alternative E2 receptor present in both luminal and aggressive triple-negative breast cancer and is related to TMX resistance and cancer progression. The roles of GPR30 and IL-6 in metastasis have been individually established; however, their interplay remains unexplored. This study aims to elucidate the role of GPR30 in IL-6-induced metastatic properties of MCF-7 luminal breast cancer cells. Results showed that GPR30 contributes to the E2-induced MCF-7 proliferation because its inhibition with the antagonist G15 and the Pertussis toxin (PTX) reduced it. Besides, GPR30 upregulated vimentin and downregulated E-cadherin levels in MCF-7 and TMX-resistant (R-TMX) cells and is also involved in the IL-6-induced migration, invasion, and TMX resistance in MCF-7 cells. In addition, in MDA-MB-231 triple-negative cells, both basal and IL-6-induced metastatic properties were related to GPR30 activity. These results indicate that the GPR30 receptor regulates the EMT induced by IL-6 in breast cancer cells.

GPER involvement in inflammatory pain

Chronic pain is a worldwide refractory health disease that causes major financial and emotional burdens and that is devastating for individuals and society. One primary source of pain is inflammation. Current treatments for inflammatory pain are weakly effective, although they usually replace analgesics, such as opioids and non-steroidal anti-inflammatory drugs, which display serious side effects. Emerging evidence indicates that the membrane G protein-coupled estrogen receptor (GPER) may play an important role in the regulation of inflammation and pain. Herein, we focus on the consequences of pharmacological and genetic GPER modulation in different animal models of inflammatory pain. We also provide a brief overview of the putative mechanisms including the direct action of GPER on pain transmission and inflammation.

Tailoring Potential Natural Compounds for the Treatment of Luminal Breast Cancer

Breast cancer (BC) is the most diagnosed cancer worldwide, mainly affecting the epithelial cells from the mammary glands. When it expresses the estrogen receptor (ER), the tumor is called luminal BC, which is eligible for endocrine therapy with hormone signaling blockade. Hormone therapy is essential for the survival of patients, but therapeutic resistance has been shown to be worrying, significantly compromising the prognosis. In this context, the need to explore new compounds emerges, especially compounds of plant origin, since they are biologically active and particularly promising. Natural products are being continuously screened for treating cancer due to their chemical diversity, reduced toxicity, lower side effects, and low price. This review summarizes natural compounds for the treatment of luminal BC, emphasizing the activities of these compounds in ER-positive cells. Moreover, their potential as an alternative to endocrine resistance is explored, opening new opportunities for the design of optimized therapies.

Different Expression Pattern of G Protein-Coupled Estrogen Receptor GPER1 in Esophageal Squamous Cell Carcinoma and Adenocarcinoma

Esophageal carcinoma is a male-dominant malignancy worldwide, and esophageal adenocarcinoma (EAC) shows more significant sex bias than esophageal squamous cell carcinoma (ESCC) in morbidity and mortality. The G protein-coupled estrogen receptor 1 (GPER1) is involved in several sex-related cancers; however, its expression level in esophageal carcinoma has been poorly investigated and its role is not precisely defined, depending on histological types. In the present study, the mRNA levels of GPER1 in esophageal carcinoma were collected from GEPIA and Oncomine databases for meta-analyses. The protein expression levels of GPER1 were detected by immunohistochemistry in the tissue microarray of EAC and ESCC. The GPER1 selective agonist G1, antagonist G15, and siRNA were applied in vitro to investigate their impacts on esophageal cell lines. Analysis of the RNA levels from the databases showed a decreased expression of GPER1 in overall esophageal carcinoma, and low expression levels of GPER1 were found to be associated with low survival of tumor patients. However, in the subgroup of EAC and its precancerous lesion, Barrett's esophagus, overexpression of GPER1 RNA was increased when compared with the normal tissues. The average staining scores of GPER1 protein in the tissue microarray of EAC were significantly higher than normal esophageal samples, and the rate of positive staining increased with the grade of poor tumor differentiation. The scores of GPER1 protein in ESCC tissues were lower than those in the normal tissues. The results from cell line experiments in vitro showed that the GPER1 agonist G1 inhibited proliferation and promoted apoptosis of ESCC cells EC109 with positive expression of GPER1. G1 had no obvious effect on normal esophageal NE2 cells with weak expression of GPER1. In addition, GPER1 RNA knockdown and application of antagonist G15 reversed the effects of G1 on EC109. The results of this study indicate that the expression levels of GPER1 are higher in EAC than in ESCC, which might be correlated with the dimorphic estrogen signaling pathway in different types of esophageal carcinoma.

Overview of the therapeutic strategies for ER positive breast cancer

Estrogen Receptor is the driving transcription factor in about 75% of all breast cancers, which is the target of endocrine therapies, but drug resistance is a common clinical problem. ESR1 point mutations at the ligand binding domain are frequently identified in metastatic tumor and ctDNA (Circulating tumor DNA) derived from ER positive breast cancer patients with endocrine therapies. Although endocrine therapy and CDK4/6 inhibitor therapy have demonstrated preclinical and clinical benefits for breast cancer, the development of resistance remains a significant challenge and the detailed mechanisms, and potential therapeutic targets in advanced breast cancer yet to be revealed. Since a crosstalk between tumor and tumor microenvironment (TME) plays an important role to grow tumor and metastasis, this effect could serve as key regulators in the resistance of endocrine therapy and the transition of breast cancer cells to metastasis. In this article, we have reviewed recent progress in endocrine therapy and the contribution of TME to ER positive breast cancer.

Expression of MiRNA-29b and MiRNA-31 and their diagnostic and prognostic values in Egyptian females with breast cancer

Breast cancer is a major health threat to women globally. Many circulating microRNAs are non-invasive cancer biomarkers. In this study, the expression of miR-29b and miR-31 was assessed in blood samples from 200 patients with breast cancer and wholesome volunteer women using quantitative reverse transcriptase PCR to evaluate their role in the disease. MiR-29b was significantly overexpressed in patients compared to controls. Multivariate regression analysis showed that it was an established risk factor for relapse and mortality. MiR-31 was significantly under-expressed in patients. It was an established risk factor for relapse and was strongly associated with mortality. For the prediction of relapse, miR-29b had a sensitivity of 81.25% and a specificity of 88.24% at a cutoff of > 30.09, while miR-31 had a sensitivity of 87.50% and a specificity of 79.41% at a cutoff of 0.12. The specificity was enhanced to 100% by combining the values of miR-29b and miR-31. In predicting mortality, miR-29b exhibited a sensitivity of 90% and a specificity of 97.5% at a cutoff of > 48.10. At a cutoff of 0.119, miR-31 exhibited a sensitivity of 87.50% and a specificity of 79.41%. High miR-29b expression and low miR-31 expression were linked with a low survival rate. MiR-29b and miR-31 could be useful markers for predicting breast cancer relapse and mortality.

Comprehensive analysis of a new immune-related prognostic signature for esophageal cancer and its correlation with infiltrating immune cells and target genes

Background

The incidence of esophageal cancer (ESCA) is increasing rapidly, and the 5-year survival rate is less than 20%. This study provides new ideas for clinical treatment by establishing a prognostic signature composed of immune-related genes (IRGs), and fully analyzing its relationship with target genes and the tumor microenvironment (TME).

Methods

We downloaded the ESCA expression matrix and clinical information from The Cancer Genome Atlas (TCGA) database. Differential expression genes (DEGs) were identified with the edgeR package and crossed with the IRGs we obtained from the ImmPort database to obtain differential IRGs (DEIRGs). The prognostic signature was then obtained through univariate Cox, LASSO-Cox, and multivariate Cox analyses. The receiver operating characteristic (ROC) curve was used to evaluate the prediction effect of the model. The immune cell infiltration abundance obtained by ssGSEA and therapeutic target genes was used to perform sufficient correlation analysis with the obtained prognostic signature and related genes.

Results

A total of 173 samples were obtained from TCGA database, including 162 tumor and 11 normal samples. The 3,033 differential genes were used to obtain 254 DEIRGs by intersections with 2,483 IRGs (IRGs) obtained from the ImmPort Database. Finally, multivariate Cox regression analysis identified eight prognostic DEIRGs and established a new prognostic signature (HR: 2.49, 95% CI: 1.68–3.67; P<0.001). Based on the expression of the eight genes, the cohort was then divided into high and low risk groups and Kaplan-Meier (K-M) curves were plotted with the log-rank test P<0.0001 and 1-, 3-year area under the curve (AUC) >0.7. The K-M curves grouped according to high and low risks performed well in the two subgroup validation cohorts, with log-rank test P<0.05. There were differences in the degree of infiltration of 16 kinds of immune cells in tumor and normal samples, and the infiltration abundance of 12 kinds of immune cells was different in the high and low-risk groups.

Conclusions

An effective and validated prognostic signature composed of IRGs was established and had a strong correlation with immune cells and target genes of drug therapy.