MicroRNAs and Androgen Receptor: Emerging Players in Breast Cancer

MicroRNA signature of stromal-epithelial interactions in prostate and breast cancers

Stromal-epithelial communication is an absolute necessity when it comes to the morphogenesis and pathogenesis of solid tissues, including the prostate and breast. So far, signalling pathways of several growth factors have been investigated. Besides such chemical factors, non-coding RNAs such as miRNAs have recently gained much interest because of their variety and complexity of action. Prostate and breast tissues being highly responsive to steroid hormones such as androgen and estrogen, respectively, it is not surprising that a huge set of available literature critically investigated the interplay between such hormones and miRNAs, especially in carcinogenesis. This review showcases our effort to highlight hormonally-related miRNAs that also somehow perturb the regular stromal-epithelial interactions during carcinogenesis in the prostate and breast. In future, we look forward to exploring how hormonal changes in the tissue microenvironment bring about miRNA-mediated changes in stromal-epithelial interactome in carcinogenesis and cancer progression.

ER Negative Breast Cancer and miRNA: There Is More to Decipher Than What the Pathologist Can See!

Breast cancer (BC), the most prevalent cancer in women, is a heterogenous disease. Despite advancements in BC diagnosis, prognosis, and therapeutics, survival rates have drastically decreased in the metastatic setting. Therefore, BC still remains a medical challenge. The evolution of high-throughput technology has highlighted gaps in the classification system of BCs. Of particular interest is the notorious triple negative BC, which was recounted as being heterogenous itself and it overlaps with distinct subtypes, namely molecular apocrine (MA) and luminal androgen (LAR) BCs. These subtypes are, even today, still misdiagnosed and poorly treated. As such, researchers and clinicians have been looking for ways through which to refine BC classification in order to properly understand the initiation, development, progression, and the responses to the treatment of BCs. One tool is biomarkers and, specifically, microRNA (miRNA), which are highly reported as associated with BC carcinogenesis. In this review, the diverse roles of miRNA in estrogen receptor negative (ER-) and androgen receptor positive (AR+) BC are depicted. While highlighting their oncogenic and tumor suppressor functions in tumor progression, we will discuss their diagnostic, prognostic, and predictive biomarker potentials, as well as their drug sensitivity/resistance activity. The association of several miRNAs in the KEGG-reported pathways that are related to ER-BC carcinogenesis is presented. The identification and verification of accurate miRNA panels is a cornerstone for tackling BC classification setbacks, as is also the deciphering of the carcinogenesis regulators of ER - AR + BC.

MicroRNAs within the Basal-like signature of Quadruple Negative Breast Cancer impact overall survival in African Americans

We previously found that QNBC tumors are more frequent in African Americans compared to TNBC tumors. To characterize this subtype further, we sought to determine the miRNA-mRNA profile in QNBC patients based on race. Both miRNA and mRNA expression data were analyzed from TCGA and validated using datasets from the METABRIC, TCGA proteomic, and survival analysis by KMPLOT. miRNA-mRNAs which include FOXA1 and MYC (mir-17/20a targets); GATA3 and CCNG2 (mir-135b targets); CDKN2A, CDK6, and B7-H3 (mir-29c targets); and RUNX3, KLF5, IL1-β, and CTNNB1 (mir-375 targets) were correlated with basal-like and immune subtypes in QNBC patients and associated with a worse survival. Thus, QNBC tumors have an altered gene signature implicated in racial disparity and poor survival.

Comparative G-Protein-Coupled Estrogen Receptor (GPER) Systems in Diabetic and Cancer Conditions: A Review

For many patients, diabetes Mellitus and Malignancy are frequently encountered comorbidities. Diabetes affects approximately 10.5% of the global population, while malignancy accounts for 29.4 million cases each year. These troubling statistics indicate that current treatment approaches for these diseases are insufficient. Alternative therapeutic strategies that consider unique signaling pathways in diabetic and malignancy patients could provide improved therapeutic outcomes. The G-protein-coupled estrogen receptor (GPER) is receiving attention for its role in disease pathogenesis and treatment outcomes. This review aims to critically examine GPER' s comparative role in diabetes mellitus and malignancy, identify research gaps that need to be filled, and highlight GPER's potential as a therapeutic target for diabetes and malignancy management. There is a scarcity of data on GPER expression patterns in diabetic models; however, for diabetes mellitus, altered expression of transport and signaling proteins has been linked to GPER signaling. In contrast, GPER expression in various malignancy types appears to be complex and debatable at the moment. Current data show inconclusive patterns of GPER expression in various malignancies, with some indicating upregulation and others demonstrating downregulation. Further research should be conducted to investigate GPER expression patterns and their relationship with signaling pathways in diabetes mellitus and various malignancies. We conclude that GPER has therapeutic potential for chronic diseases such as diabetes mellitus and malignancy.

CircRNA RNF10 inhibits tumorigenicity by targeting miR-942-5p/GOLIM4 axis in breast cancer

We aimed to explore the action of a circRNA produced by ring finger protein 10 (circ_RNF10; hsa_circ_0028899) in the malignant behaviors of breast cancer (BC) and to explore its potential action-of-mechanism. The levels of circ_RNF10, miR-942-5p and Golgi integral membrane protein 4 (GOLIM4) were measured through quantitative real-time polymerase chain reaction, western blot, or immunohistochemistry, and the competing endogenous RNA (ceRNA) relationship among them was verified by dual-luciferase reporter assay. Cell counting kit-8, 5-ethynyl-2'-deoxyuridine, and colony formation assays, transwell assays, and flow cytometry were used to examine cell proliferation, migration and invasion, and apoptosis, respectively. Levels of proliferation and invasion-related markers were determined by western blot. Xenograft assay was performed to assess tumor growth. Circ_RNF10 level was significantly reduced in BC tissues and cells. Elevation of circ_RNF10 blocked BC cell proliferation, migration and invasion while promoted the apoptosis in vitro, companied with decreased PCNA and Twist1 and increased E-cadherin. Furthermore, upregulating circ_RNF10 delayed tumor growth of BC cells in nude mice. Mechanistically, circ_RNF10 acted as a ceRNA for miR-942-5p, and miR-942-5p could target GOLIM4. In addition, miR-942-5p overexpression reversed the influence of circ_RNF10 overexpression on BC progression. Furthermore, GOLIM4 silencing attenuated the inhibitory effect of miR-942-5p knockdown on BC progression. We found that circ_RNF10 suppressed BC malignant behavior by targeting miR-942-5p/GOLIM4 axis.

Potential epigenetic modifications implicated in triple- to quadruple-negative breast cancer transition: a review

Current research on triple-negative breast cancer (TNBC) has resulted in delineation into the quadruple-negative breast cancer (QNBC) subgroup. Epigenetic modifications such as DNA methylation, histone posttranslational modifications and associated changes in chromatin architecture have been implicated in breast cancer pathogenesis. Herein, the authors highlight genes with observed epigenetic modifications that are associated with more aggressive TNBC/QNBC pathogenesis and possible interventions. Advanced literature searches were done on PubMed/MEDLINE, Scopus and Google Scholar. The results suggest that nine epigenetically altered genes/differentially expressed proteins in addition to the downregulated androgen receptor are associated with TNBC aggressiveness and could be implicated in the TNBC to QNBC transition. Thus, restoring the normal expression of these genes via epigenetic reprogramming could be therapeutically beneficial to TNBC and QNBC patients.

Androgen receptor expression and prognosis in Hispanic/Latino women with triple negative breast cancer

INTRODUCTION AND OBJECTIVE

Triple-negative breast cancer (TNBC) is an aggressive subtype that has no available molecular targets. It occurs most often in premenopausal African-American and Hispanic/Latino women. In Colombia, its prevalence has been reported to be 20.6%. Androgen receptor (AR) belongs to the steroid nuclear receptor family and has been recently considered a potential biomarker for breast cancer. Considering the high prevalence of TNBC in Colombian women and the lack of knowledge of AR expression, our aim was to determine the frequency of AR expression and its association with pathological variables.

MATERIALS AND METHODS

149 women diagnosed with TNBC between 2011 and 2014 were included. Clinical and pathological data were obtained from medical and pathology reports. Information on hormone receptor status, Ki67 expression and HER2 was reevaluated by a pathologist. AR expression was considered positive when it exceeded 1% of nuclear staining in tumor cells.

RESULTS

AR expression was detected in 41.6% of the samples. Although we did not find statistically significant differences in clinic-pathological variables according to AR expression, patients with AR expression over 50% were younger (53.92 years vs. 60.78 years, p=0.027) and presented higher Ki67 expression (64.06% vs. 47.32%, p=0.05), compared to patients with a low AR expression. The median overall survival in our sample of TNBC patients was 2.45 years.

CONCLUSIONS

The expression of AR in our sample was similar to the expression in populations of European descent. We found statistically significant differences in age at diagnosis and Ki67 expression according to AR expression.

Translational Implications of Dysregulated Pathways and MicroRNA Regulation in Quadruple-Negative Breast Cancer

Triple-negative breast cancers (HER2−, ER−, PR−) continue to present a unique treatment challenge and carry unfavorable prognoses. The elucidation of novel therapeutic targets has necessitated the re-evaluation of stratification approaches to best predict prognosis, treatment response and theranostic and prognostic markers. Androgen receptor expression and function have important implications on proliferation, tumor progression, immunity and molecular signaling in breast cancer. Accordingly, there has been increasing support for classification of androgen receptor-negative triple-negative breast cancer or quadruple-negative breast cancer (QNBC). QNBC has unique molecular, signaling and expression regulation profiles, particularly those affected by microRNA regulatory networks. MicroRNAs are now known to regulate AR-related targets and pathways that are dysregulated in QNBC, including immune checkpoint inhibitors (ICIs), SKP2, EN1, ACSL4 and EGFR. In this review, we explore and define the QNBC tumor subtype, its molecular and clinical distinctions from other subtypes, miRNA dysregulation and function in QNBC, and knowledge gaps in the field. Potential insights into clinical and translational implications of these dysregulated networks in QNBC are discussed.

Early Detection and Investigation of Extracellular Vesicles Biomarkers in Breast Cancer

Breast cancer (BC) is the most commonly diagnosed malignant tumor in women worldwide, and the leading cause of cancer death in the female population. The percentage of patients experiencing poor prognosis along with the risk of developing metastasis remains high, also affecting the resistance to current main therapies. Cancer progression and metastatic development are no longer due entirely to their intrinsic characteristics, but also regulated by signals derived from cells of the tumor microenvironment. Extracellular vesicles (EVs) packed with DNA, RNA, and proteins, are the most attractive targets for both diagnostic and therapeutic applications, and represent a decisive challenge as liquid biopsy-based markers. Here we performed a study based on a multiplexed phenotyping flow cytometric approach to characterize BC-derived EVs from BC patients and cell lines, through the detection of multiple antigens. Our data reveal the expression of EVs-related biomarkers derived from BC patient plasma and cell line supernatants, suggesting that EVs could be exploited for characterizing and monitoring disease progression.

MicroRNA-506-3p inhibits colorectal cancer cell proliferation through targeting enhancer of zeste homologue 2

A large number of studies have shown that microRNA (miRNA) has an important relationship with the occurrence and development of colorectal cancer (CRC), but its specific molecular mechanism has not been fully elucidated. This study is to explore the influence of miR-506-3p on the malignant behavior of CRC and its underlying molecular mechanism. Our results show that miR-506-3p was lowly expressed and enhancer of zeste homologue 2 (EZH2) was highly expressed in CRC. Overexpressing miR-506-3p or silencing EZH2 inhibited CRC cell proliferation, migration and invasion and promoted apoptosis. Inhibiting miR-506-3p promoted CRC cell proliferation, migration and invasion but inhibited apoptosis. These impacts were reversed after co-transfecting si-EZH2. Further mechanism studies have shown that miR-506-3p can reduce EZH2 expression in CRC cells by binding to the 3ʹUTR end of EZH2. In summary, the results of this study show that miR-506-3p inhibited CRC progression through targeting EZH2 expression. This provides a new molecular target for the clinical treatment of CRC in the future.

Urine as a Source of Liquid Biopsy for Cancer

Simple Summary

Tissue biopsy is essential for diagnosis and characterization of a tumor. Recently circulating tumor cells and other tumor-derived nucleic acid can be detected from blood, which is called liquid biopsy. Now this concept has been expanded to many other body fluids including urine. Urine is the least invasive method to obtain a liquid biopsy and can be done anywhere, which allows longitudinal repeated sampling. Here, we review the latest update on urine liquid biopsy in urological and non-urological cancers.

Abstract

Tissue biopsy is the gold standard for diagnosis and morphological and immunohistochemical analyses to characterize cancer. However, tissue biopsy usually requires an invasive procedure, and it can be challenging depending on the condition of the patient and the location of the tumor. Even liquid biopsy analysis of body fluids such as blood, saliva, gastric juice, sweat, tears and cerebrospinal fluid may require invasive procedures to obtain samples. Liquid biopsy can be applied to circulating tumor cells (CTCs) or nucleic acids (NAs) in blood. Recently, urine has gained popularity due to its less invasive sampling, ability to easily repeat samples, and ability to follow tumor evolution in real-time, making it a powerful tool for diagnosis and treatment monitoring in cancer patients. With the development and advancements in extraction methods of urinary substances, urinary NAs have been found to be closely related to carcinogenesis, metastasis, and therapeutic response, not only in urological cancers but also in non-urological cancers. This review mainly highlights the components of urine liquid biopsy and their utility and limitations in oncology, especially in non-urological cancers.

Urinary microRNA and mRNA in Tumors

Liquid biopsy is gaining importance in the context of analysis of circulating subcellular components, such as exosomes and nucleic acids, and the investigation of biological fluids is increasing because they express features common to the tissue of origin. Particularly, urine has become one of the most attractive biofluids in clinical practice due to its easy collection approach, its availability of large quantities, and its noninvasiveness. Furthermore, a peculiarity is that, compared to serum or plasma, urine is characterized by a simpler composition that improves isolation and identification of biomarkers. Recent studies have been associated with the investigation of mRNAs and microRNAs as potential noninvasive cancer biomarkers in urine, and to date, several approaches for isolating and measuring urinary nucleic acids have been established, despite still developing. This chapter aims at giving some main published evidences on urinary microRNAs and mRNAs, with the intent to consider their potential translational use in clinical practice.

Correlation between Androgen Receptor Expression and Immunohistochemistry Type as Prognostic Factors in a Cohort of Breast Cancer Patients: Result from a Single-Center, Cross Sectional Study

Background: We investigated the correlation between the androgen receptor (AR) and immunohistochemistry (IHC) as a prognostic factor in breast cancer (BC). AR is expressed in 60–80% of BC. Methods: We evaluated the prognostic values of AR expression among 143 patients with BC for 36 months. The protocol was amended to measure androgen, estrogen and progesterone receptor expression by IHC and the percentage of hormone positive nuclei was quantified. We determined and quantified the Her2/neu status using IHC and in situ hybridization. The methodology consisted in using a Kaplan–Meier analysis and restricted mean survival time up to 36 months. The principal endpoints of the study were overall survival (OS) and progression free survival (PFS). Results: 57% of patients (n = 82) from our group had AR+ (≥ 1%). Patients with AR+ had better OS, 35.50 vs. 33.40 months, with p = 0.027. Moreover, PFS was prolonged for patients AR+, 32.60 vs. 30.50 months, with p = 0.38. Triple negative breast cancer (TNBC) patients had lower OS and no difference was observed for PFS. Conclusions: Both OS and PFS were favorably influenced by the presence of AR. TNBC had worse outcomes compared with patients with hormonal or/and Her 2/neu positive disease in terms of OS.

Non-coding RNAs regulating androgen receptor signaling pathways in prostate cancer

Prostate cancer (PCa) is one of the most common malignancies for men worldwide, and abnormal activation of the androgen receptor (AR) signaling plays an important role in the progression of PCa. However, in the androgen deprivation therapy (ADT), AR signaling inevitably recovered, as a result, exploring novel regulating mechanisms is of great importance. Recently, non-coding RNAs (ncRNAs), including microRNAs, long non-coding RNAs, circular RNAs, could be involved in the progression of PCa, and participate in the regulatory network of AR signaling in a variety of ways. This will help to identify novel molecular mechanisms to promote the development of PCa and find new potential therapeutic targets. In this review, we provide a synopsis of the latest research relating to ncRNAs and associated AR signaling in PCa.

Role of androgen and microRNA in triple-negative breast cancer

Breast cancer (BC) is the most frequent type of malignancy affecting females worldwide. Molecular-based studies resulted in an identification of at least four subtypes of breast carcinoma, including luminal A and luminal B, Human growth factor receptor (HER-2)-enriched and triple-negative tumors (basal-like and normal breast-like). A proportion of BC cases are of the triple-negative breast cancer (TNBC) type. TNBC lacks the expression of estrogen receptor (ER), progesterone receptor (PR), and HER-2, and is known to express androgen receptor (AR) at considerable levels. AR has been shown to promote the progression of TNBC. However, the exact mechanisms have yet to be unraveled. One of these mechanisms could be through regulating the expression of microRNA (miRNA) molecules, which play an important regulatory role in BC through post-transcriptional gene silencing. Activation of AR controls the expression of miRNA molecules, which target selective mRNAs, consequently, affecting protein expression. In this review we attempt to elucidate the relations between AR and miRNA in TNBC.

Dysregulated microRNAs in Hepatitis B Virus-Related Hepatocellular Carcinoma: Potential as Biomarkers and Therapeutic Targets

MicroRNAs (miRNAs) are non-coding small RNAs that can function as gene regulators and are involved in tumorigenesis. We review the commonly dysregulated miRNAs in liver tumor tissues and plasma/serum of hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC) patients. The frequently reported up-regulated miRNAs in liver tumor tissues include miR-18a, miR-21, miR-221, miR-222, and miR-224, whereas down-regulated miRNAs include miR-26a, miR-101, miR-122, miR-125b, miR-145, miR-199a, miR-199b, miR-200a, and miR-223. For a subset of these miRNAs (up-regulated miR-222 and miR-224, down-regulated miR-26a and miR-125b), the pattern of dysregulated circulating miRNAs in plasma/serum is mirrored in tumor tissue based on multiple independent studies. Dysregulated miRNAs target oncogenes or tumor suppressor genes involved in hepatocarcinogenesis. Normalization of dysregulated miRNAs by up- or down-regulation has been shown to inhibit HCC cell proliferation or sensitize liver cancer cells to chemotherapeutic treatment. miRNAs hold as yet unrealized potential as biomarkers for early detection of HCC and as precision therapeutic targets, but further studies in diverse populations and across all stages of HCC are needed.

FOXO1 and hsa-microRNA-204-5p affect the biologic behavior of MDA-MB-231 breast cancer cells

RNA molecules and targeting microRNA (miRNA) have been reported as novel focuses in recent research on breast cancer. This study aimed to probe the expression of FOXO1 in the MDA-MB-231 cell line and to explore the target effects of FOXO1 with hsa-microRNA-204-5p (miR-204) on the biologic behavior of MDA-MB-231 cells. The expression of FOXO1 mRNA and protein in MDA-MB-231 cells were derived and verified from the public databases, literature, and experimental assays, then the downregulation of FOXO1 was confirmed in the MDA-MB-231 cell line. The target binding of FOXO1 and miR-204 was predicted by miRWalk and confirmed by luciferase reporter assays. MiR-204 targeted the 3' untranslated region of FOXO1 and reduced FOXO1 expression in miR-204-transfected cells, resulting in cell growth amplification but inhibition of cell migration and apoptosis, which were assessed using the MTT method, wound healing assays, and flow cytometry, respectively. The protein levels of serine-threonine kinase (AKT), c-jun N-terminal kinase (JNK), extracellular regulatory protein kinase (ERK), and the phosphorylated protein kinases (P-AKT, P-JNK, and P-ERK) were measured by western blot. It was found that AKT, JNK, and ERK remained constant, but P-AKT, P-JNK, and P-ERK were upregulated after miR-204 transfection. In summary, the expression of FOXO1 was downregulated in MDA-MB-231 cells; and the target binding of miR-204 and FOXO1 affected phosphatidylinositol 3-kinase (PI3K)/AKT and mitogen-activated protein kinase (MAPK) signal pathways, leading to different alterations of cellular activity in MDA-MB-231 cells.

Comparison of the roles of estrogens and androgens in breast cancer and prostate cancer

Breast cancer (BC) and prostate cancer (PC) are the second most common malignant tumors in women and men in western countries, respectively. The risks of death are 14% for BC and 9% for PC. Abnormal estrogen and androgen levels are related to carcinogenesis of the breast and prostate. Estradiol stimulates cancer development in BC. The effect of estrogen on PC is concentration-dependent, and estrogen can regulate androgen production, further affecting PC. Estrogen can also increase the risk of androgen-induced PC. Androgen has dual effects on BC via different metabolic pathways, and the role of the androgen receptor (AR) in BC also depends on cell subtype and downstream target genes. Androgen and AR can stimulate both primary PC and castration-resistant PC. Understanding the mechanisms of the effects of estrogen and androgen on BC and PC may help us to improve curative BC and PC treatment strategies.

Controversial association between polycystic ovary syndrome and breast cancer

Polycystic ovary syndrome (PCOS) risk factors overlap with breast cancer, and the hormonal profile may be implicated in breast cancer pathogenesis. This study aims to report a literature review considering epidemiological and molecular mechanisms that correlate PCOS and breast cancer, as well as the influence of PCOS treatment on the incidence of breast cancer. Epidemiological studies failed to adjust potential variables that affect the risk and have thus provided inconclusive results. Molecular effects of androgenic pathways in breast cancer have been studied and androgens seem to have an inhibitory effect on mammary epithelial proliferation. However, increased bioavailable androgens were associated with recurrence of breast cancer due to conversion to oestrogens. Sex hormone-binding globulin has a role in hormone-dependent cancers and can be considered a marker for PCOS; a gene profile has already been linked to breast cancer risk in these patients. PCOS medical treatment is a promising tool for stratifying breast cancer risk due to the metabolic influence and hormonal environment. Clinical reports are inconsistent, emphasizing the need for further studies with a prospective design. In the future, the role of pharmacological interventions in PCOS will increase knowledge and awareness of breast cancer pathogenesis and will help to refine breast cancer risk stratification.

Hsa_circ_0008945 promoted breast cancer progression by targeting miR-338-3p

PURPOSE

To detect the expression and function of circ_0008945 in breast cancer (BC) and to explore its potential molecular mechanisms in BC tumorigenesis.

MATERIALS AND METHODS

We measured expression levels of circ_0008945, miR-338-3p and homeobox A3 (HOXA3) in BC tissue specimens and cells using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). We examined the effects of all three genes on BC cell proliferation using Cell Counting Kit-8 (CCK-8) and colony formation assays. We also performed a Transwell assay to assess the migratory and invasive ability of treated BC cells. BC cell apoptosis was assessed using flow cytometric (FCM) analysis; interaction between miR-338-3p and circ_0008945 or HOXA3 was verified by dual-luciferase reporter assay as well as by ribonucleic-acid (RNA) pulldown. Finally, we used an in vivo tumor growth assay to assess the role of circ_0008945 overexpression in BC tumor growth.

RESULTS

We found that circ_0008945 expression was significantly increased in both BC tissue specimens and cells. This increase was correlated with poor prognosis in BC patients. Knockdown of circ_0008945 inhibited BC cell proliferation, migration and invasion while promoting BC cell apoptosis in vitro. Overexpression of circ_0008945 remarkably promoted BC tumor growth in vivo. Mechanistically, circ_0008945 acted as a miRNA sponge for miR-338-3p and inhibited its expression in BC cells. Moreover, miR-338-3p targeted and inhibited HOXA3.

CONCLUSION

We found that circ_0008945 acted as a BC oncogene by physically binding miR-338-3p, which further targeted and regulated HOXA3.