miR-146a and miR-638 in BRCA1-deficient triple negative breast cancer tumors, as potential biomarkers for improved overall survival

Withaferin A alters the expression of microRNAs 146a-5p and 34a-5p and associated hub genes in MDA-MB-231 cells

Triple-negative breast cancer (TNBC) is a highly metastatic subtype of breast cancer. Due to the absence of obvious therapeutic targets, microRNAs (miRNAs) provide possible hope to treat TNBC. Withaferin A (WA), a steroidal lactone, possesses potential anticancer activity with lesser side effects. The present study identifies hub genes (CDKN3, TRAF6, CCND1, JAK1, MET, AXIN2, JAG1, VEGFA, BRCA1, E2F3, WNT1, CDK6, KRAS, MYB, MYCN, TGFβR2, NOTCH1, SIRT1, MYCN, NOTCH2, WNT3A) from the list of predicted targets of the differentially expressed miRNAs (DEMs) in WA-treated MDA-MB-231 cells using in silico protein-protein interaction network analysis. CCND1, CDK6, and TRAF6 hub genes were predicted as targets of miR-34a-5p and miR-146a-5p, respectively. The study found the lower expression of miR-34a-5p and miR-146a-5p in MDA-MB-231 cells, and further, it was observed that WA treatment effectively restored the lost expression of miR-34a-5p and miR-146a-5p in MDA-MB-231 cells. An anti-correlation expression pattern was found among the miR-34a-5p and miR-146a-5p and the respective target hub genes in WA-treated TNBC cells. In conclusion, WA might exert anti-cancer effect in TNBC cells by inducing miR-34a-5p and miR-146a-5p expressions and decreasing CCND1, CDK6, and TARF6 target hub genes in TNBC cells.

miRNAs in the prognosis of triple-negative breast cancer: A review

Triple-Negative Breast Cancer (TNBC) is a highly aggressive and invasive type of breast cancer (BC) with high mortality rate wherein effective target medicaments are lacking. It is a very heterogeneous group with several subtypes that account for 10-20% of cancer among women globally, being negative for three most important receptors (estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2)), with an early and high recurrence resulting in poor survival rate. Therefore, a more thorough knowledge on carcinogenesis of TNBC is required for the development of personalized treatment options. miRNAs can either promote or suppress tumorigenesis and have been linked to a number of features of cancer progression, including proliferation, metastasis, apoptosis, and epithelial-mesenchymal transition (EMT). Recent miRNA research shows that there is great potential for the development of novel biomarkers as they have emerged as drivers of tumorigenesis and provide opportunities to target various components involved in TNBC, thus helping to solve this difficult-to-treat disease. In this review, we summarize the most relevant miRNAs that play an essential role in TNBC biology. Their role with regard to molecular mechanisms underlying TNBC progression has been discussed, and their potential use as therapeutic or prognostic markers to unravel the intricacy of TNBC based on the pieces of evidence obtained from various works of literature has been briefly addressed.

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.

Repression of miR-146a in predicting poor treatment outcome in triple-negative breast cancer

OBJECTIVES

In the era of precision medicine, the highly aggressive and heterogenous triple-negative breast cancer (TNBC) is still characterized by limited options to support personalized prognosis and guide therapeutic interventions. Thereafter, the aim of the present study has been the thorough evaluation of miR-146a as a novel molecular indicator of TNBC prognosis and treatment outcome, utilizing four independent TNBC cohorts.

DESIGN & METHODS

miR-146a levels were clinically evaluated in our screening (n = 122) and three external validation TNBC cohorts (de Rinaldis et al. 2013, n = 114; Jézéquel et al. 2015, n = 107; TCGA, n = 180). Analysis of miR-146a and validated gene targets was performed in Jézéquel et al. and TCGA validation cohorts. Patients' survival, recurrence and metastasis were determined as clinical endpoints for the survival analysis. Internal validation was performed by bootstrap analysis and clinical net benefit was evaluated by decision curve analysis.

RESULTS

Reduction of miR-146a is strongly associated with patients' poor survival and can predict post-treatment disease early-recurrence, independently of tumor size, lymph node status, histological grade and patients' age. The analysis of the external validation cohorts corroborated the unfavorable nature of miR-146a repression regarding patients' survival and, strikingly, unveiled the ability of miR-146a to predict TNBC metastasis. Combined assessment of miR-146a levels and lymph node status resulted in superior risk-stratification of TNBC patients and higher clinical benefit regarding disease prognosis and post-treatment outcome. Ultimately, miR-146a was negatively associated with EGFR and SOX2 expression in TNBC.

CONCLUSIONS

miR-146a evaluation could ameliorate personalized prognosis and support precision medicine decisions in TNBC.

The Role of miRNAs in the Prognosis of Triple-Negative Breast Cancer: A Systematic Review and Meta-Analysis

Breast cancer is one of the most common malignancies among women around the world. The basal or triple-negative subtype (TNBC) is a heterogeneous group of tumors, characterized by its aggressive and metastatic nature, with low survival and worse prognosis. Research on genetic biomarkers, such as microRNAs (miRs) in TNBC, demonstrate their relevance in the prognosis of the disease. Therefore, the objective of this research was to verify the role of miRs in the prognosis of TNBC. A search was carried out in the PubMed (MEDLINE), Web of Science, and Scopus databases, with articles in the English language from 2010 to 2022. Only articles that analyzed the role of miRNAs in the prognosis of TNBC and that met the criteria of the MOOSE method were included. For the preparation and planning of this systematic review, a PRISMA checklist and the MOOSE method were used. The Newcastle-Ottawa Scale was used to analyze the quality of the included studies. The excluded criteria considered were: (1) studies that presented duplication in the databases; (2) reviews of the literature, clinical case reports, meta-analyses, conference abstracts, letters to the editor, theses, dissertations, and book chapters; (3) studies that stratified only women diagnosed with other subtypes of breast cancer subtypes; (4) experiments without a control or comparison group. After the bibliographic survey of the 2.274 articles found, 43 articles met the inclusion criteria, totaling 5421 patients with TNBC analyzed for this review. Six miRs (miR-155, miR-21, miR-27a/b/, miR-374a/b, miR-30a/c/e, and miR-301a) were included in the meta-analysis. A low expression of miR-155 was associated with reduced overall survival (OS) (HR: 0.68, 95% CI: 0.58-0.81). A high expression of miR-21 was a predictor of OS reduction (HR: 2.56; 95% CI: 1.49-4.40). In addition, high levels of miR-27a/b and miR-301a/b were associated with lower OS, while the decreased expression levels of miR-30 and miR-374a/b were associated with worse relapse-free survival (RFS) and shorter disease-free survival (DFS), respectively. The present study revealed that miRs play essential roles in the development of metastases, in addition to acting as suppressors of the disease, thus improving the prognosis of TNBC. However, the clinical application of these findings has not yet been investigated.

Investigation of BRCAness associated miRNA-gene axes in breast cancer: cell-free miR-182-5p as a potential expression signature of BRCAness

The concept of the ‘BRCAness’ phenotype implies the properties that some sporadic breast cancers (BC) share with BRCA1/2-mutation carriers with hereditary BC. Breast tumors with BRCAness have deficiencies in homologous recombination repair (HRR), like BRCA1/2-mutation carriers, and consequently could benefit from poly-(ADP)-ribose polymerase (PARP) inhibitors and DNA-damaging chemotherapy. Triple-negative breast cancers (TNBC) show a higher frequency of BRCAness than the other BC subtypes. Therefore, looking for BRCAness-related biomarkers could improve personalized management of TNBC patients. microRNAs (miRNAs) play a pivotal role in onco-transcriptomic profiles of tumor cells besides their suitable features as molecular biomarkers. The current study aims to evaluate the expression level of some critical miRNAs-mRNA axes in HRR pathway in tumors and plasma samples from BC patients. The expression levels of three multi-target miRNAs, including miR-182-5p, miR-146a-5p, and miR-498, as well as six downstream HRR-related protein-coding genes, have been investigated in the breast tumors and paired adjacent normal tissues by Real-time PCR. In the next step, based on the results derived from the previous step, we examined the level of cell-free miR-182-5p in the blood plasma samples from the patients. Our results highlight the difference between TNBC and non-TNBC tumor subgroups regarding the dysregulation of the key miRNA/mRNA axes involved in the HRR pathway. Also, for the first time, we show that the level of cell-free miR-182-5p in plasma samples from BC patients could be a clue for screening BC patients eligible for receiving PARP inhibitors through a personalized manner. Altogether, some sporadic BC patients, especially sporadic TNBC, have epigenetically dysregulated HRR pathway that could be identified and benefit from BRCAness-specific therapeutic agents.

miR-638 Serves as a Biomarker of 5-Fluorouracil Sensitivity to Neoadjuvant Chemotherapy in Breast Cancer

Purpose

Neoadjuvant chemotherapy (NAC) is widely used to treat breast cancer (BC). The prediction and evaluation of chemotherapy responses remains a significant challenge.

Methods

MicroRNAs (miRNAs) play a crucial role in cancer drug resistance. We used a miRNA microarray and identified that miR-638 is downregulated in chemoresistant cases. However, the exact role of miR-638 and the underlying mechanisms of chemoresistance remain unclear. Using real-time quantitative reverse transcription polymerase chain reaction, we found significant downregulation of miR-638 in chemoresistant patients compared with chemosensitive patients. To explore the function of miR-638, we overexpressed and inhibited miR-638 expression in MDA-MB-231 and MCF-7 cells by transfecting them with miR-638 mimics and miR-638 inhibitor, respectively. Cell proliferation and apoptosis were measured using MTS and flow cytometry, respectively. A minimal patient-derived xenograft (MiniPDX™) model was established to evaluate the chemosensitivity to different drugs.

Results

The results showed that cell proliferation decreased and cell apoptosis increased in cells transfected with the miR-638 mimic, and cell proliferation and apoptosis were reversed with transfection of miR-638 inhibitor compared with the control group. Among patients who received 5-fluorouracil (5-FU), miR-638 expression levels were lower in the chemoresistant group than in the chemosensitive group. The MiniPDX™ model showed that MDA-MB-231 cells overexpressing miR-638 were more susceptible to 5-FU treatment in vivo.

Conclusion

We provided evidence of acquired resistance to 5-FU caused by miR-638 deficiency. Alterations in miR-638 may be used with 5-FU chemotherapy during NAC for BC.

Bioinformatics identification of CCL8/21 as potential prognostic biomarkers in breast cancer microenvironment

BACKGROUND

Breast cancer (BC) is the most common malignancy among females worldwide. The tumor microenvironment usually prevents effective lymphocyte activation and infiltration, and suppresses infiltrating effector cells, leading to a failure of the host to reject the tumor. CC chemokines play a significant role in inflammation and infection.

METHODS

In our study, we analyzed the expression and survival data of CC chemokines in patients with BC using several bioinformatics analyses tools.

RESULTS

The mRNA expression of CCL2/3/4/5/7/8/11/17/19/20/22 was remarkably increased while CCL14/21/23/28 was significantly down-regulated in BC tissues compared with normal tissues. Methylation could down-regulate expression of CCL2/5/15/17/19/20/22/23/24/25/26/27 in BC. Low expression of CCL3/4/23 was found to be associated with drug resistance in BC. Results from Kaplan-Meier plotter and BC Gene-Expression Miner v4.2 (bcGenExMiner) v4.2 demonstrated that BC patients with high CCL8 and low CCL19/21/22 expression were more likely to have a worse prognosis. CCL8 expression was significantly up-regulated in BC tissues compared with normal tissues. High CCL8 expression was significantly correlated with negative PR, negative ER, positive nodal status, triple-negative BC subtype, basal-like BC subtype, triple-negative and basal-like BC subtype and high grades. CCL21 was down-regulated in BC, while high levels of CCL21 was associated with negative PR, triple-negative subtype, basal-like subtype and low tumor grade. Functional analysis demonstrated that CCL8 and CCL21 were involved in carcinogenesis, tumor immune escape and chemoresistance in BC.

CONCLUSION

Integrative bioinformatics analysis demonstrated CCL8/21 as potential prognostic biomarkers in BC microenvironment.

Dysregulation of miR-638 in the progression of cancers

MicroRNA (miRNA) is a form of short, single-stranded and non-coding RNA that is important in regulating the post-transcriptional modification of multiple downstream targets. Many miRNAs have been reported to involve in controlling the progression of human diseases, and one of them is miR-638, which play essential roles in regulating the development of human cancer. By targeting the 3'-ends of its targets, miR-638 can regulate cellular processes including proliferation, invasion, metastases, angiogenesis, apoptosis and inflammation. This review was aimed to summarize current findings on the roles of miR-638 in different human cancers based on the results from various in vitro, in vivo and clinical studies. The biogenesis process and tissue expression, followed by the roles of miR-638 in regulating the development of various human cancers by targeting different downstream targets were covered in this review. The potential applications and challenges of employing miR-638 as cancer biomarker and therapeutic agent were also discussed.

The associations and roles of microRNA single-nucleotide polymorphisms in cervical cancer

Cervical cancer is one of the fourth most common gynecological malignancies and has been identified as the fourth leading cause of cancer death in women worldwide. MicroRNAs (miRNAs) are single-stranded sequences of noncoding RNAs that are approximately 22-24 nucleotides in length. They modulate posttranscriptional mRNA expression and play critical roles in cervical cancer. Single nucleotide polymorphisms (SNPs) in miRNA genes may alter miRNA expression and maturation and have been associated with various cancers. This review mainly focuses on the roles of SNPs in miRNA genes in the development of cervical cancer and summarizes the research progress of miRNA SNPs in cervical cancer and their molecular regulation mechanisms.

MiRNA and LncRNA as Potential Biomarkers in Triple-Negative Breast Cancer: A Review

Noncoding RNAs (ncRNAs) include a diverse range of RNA species, including microRNAs (miRNAs) and long noncoding RNAs (lncRNAs). MiRNAs, ncRNAs of approximately 19-25 nucleotides in length, are involved in gene expression regulation either via degradation or silencing of the messenger RNAs (mRNAs) and have roles in multiple biological processes, including cell proliferation, differentiation, migration, angiogenesis, and apoptosis. LncRNAs, which are longer than 200 nucleotides, comprise one of the largest and most heterogeneous RNA families. LncRNAs can activate or repress gene expression through various mechanisms, acting alone or in combination with miRNAs and other molecules as part of various pathways. Until recently, most research has focused on individual lncRNA and miRNA functions as regulators, and there is limited available data on ncRNA interactions relating to the tumor growth, metastasis, and therapy of cancer, acting either on mRNA alone or as competing endogenous RNA (ceRNA) networks. Triple-negative breast cancer (TNBC) represents approximately 10%-20% of all breast cancers (BCs) and is highly heterogenous and more aggressive than other types of BC, for which current targeted treatment options include hormonotherapy, PARP inhibitors, and immunotherapy; however, no targeted therapies for TNBC are available, partly because of a lack of predictive biomarkers. With advances in proteomics, new evidence has emerged demonstrating the implications of dysregulation of ncRNAs in TNBC etiology. Here, we review the roles of lncRNAs and miRNAs implicated in TNBC, including their interactions and regulatory networks. Our synthesis provides insight into the mechanisms involved in TNBC progression and has potential to aid the discovery of new diagnostic and therapeutic strategies.

Effect and mechanism of miR-146a on malignant biological behaviors of lung adenocarcinoma cell line

The aim of the present study was to assess the expression of microRNA-146a (miR-146a) in human lung adenocarcinoma cells, its effect on cellular behaviors, and the underlying molecular mechanisms. Reverse transcription-quantitative PCR (RT-qPCR) was used to measure miR-146a expression in the human normal lung epithelial cell line, BEAS-2B, and human lung adenocarcinoma cell lines, A549, PC-9 and H1299, to determine whether miR-146a acts as an oncogene or anti-oncogene. miR-146a mimics were transfected into target cells to observe the proliferation, apoptosis, invasion and migration of human lung adenocarcinoma cells. The target genes of miR-146a were predicted using bioinformatics analysis, and binding sites were validated by dual-luciferase reporter assay. Target gene expression at the mRNA and protein levels was measured by RT-qPCR and western blot analysis, respectively. The expression levels of miR-146a in human lung adenocarcinoma cell lines were lower than its expression in BEAS-2B (P<0.01). A549 cell line is a EGFR wild-type lung adenocarcinoma cell line, which is also the most widely studied in NSCLC, and therefore this was chosen as the target cell line for further investigation. Overexpression of miR-146a in A549 cells can inhibit cell proliferation (P<0.05), promote apoptosis (P<0.05), and reduce the cells' migratory ability (P<0.01). Bioinformatics prediction indicated that interleukin-1 receptor-associated kinase 1 (IRAK1) and TNF receptor associated factor 6 (TRAF6) are the target genes of miR-146a. Dual-luciferase reporter assay showed that miR-146a could specifically bind to 3′-untranslated regions of IRAK1 and TRAF6. The protein and mRNA levels of IRAK1 and TRAF6 were significantly downregulated after miR-146a overexpression in A549 cells (P<0.01). The results of this study demonstrated that the expression of miR-146a in human lung adenocarcinoma cells was significantly lower than in normal lung epithelial cells, indicating that miR-146a acts as an anti-oncogene. miR-146a suppresses the proliferation and migration of human lung adenocarcinoma cells by downregulating the expression of IRAK1 and TRAF6.

Small RNA Biosensor Design Strategy To Mitigate Off-Analyte Response

Several bottlenecks in the design of current sensor technologies for small noncoding RNA must be addressed. The small size of the sensors and the large number of other nucleotides that may have sequence similarity makes selectivity a real concern. Many of the current sensors have one strand with an exposed region called a toehold. The toehold serves as a place for the analyte nucleic acid strand to bind and initiate competitive displacement of sensors' secondary strands. Since the toehold region is not protected, any endogenous oligonucleotide sequences that are similar or only different by a few nucleic acids will interact with the toehold and cause false signals. To address sensor selectivity, we investigated how the toehold location in the sensor impacts the sensitivity and selectivity for the analyte of interest. We will discuss the differences in sensitivity and selectivity for a miR-146a-5p biosensor in the presence of different naturally occurring mismatch sequences. We found that altering the toehold location lowered the rate of the false signal from off-analyte microRNA by upward of 20 percentage points. Detection limits as low as 56 pM were observed when the sensor concentration was 5 nM. The findings herein are broadly applicable to other small and large RNAs as well as other types of sensing platforms.

miR-638 acts as an oncogene and predicts poor prognosis in renal cell carcinoma

OBJECTIVE

The aim of this study was to investigate the function and prognostic value of miR-638 in renal cell carcinoma (RCC).

METHODS

Expression of miR-638 in RCC tissues and corresponding noncancerous tissues were examined by reverse transcription quantitative polymerase chain reaction (RT-qPCR). To explore the effects of miR-638 on cell migration, invasion, viability, and apoptosis of RCC cells, wound scratch, transwell, MTT, CCK-8, and flow cytometry assays were performed. Kaplan-Meier and Cox regression analyses were used to evaluate the relationship between miR-638 expression and prognosis of RCC patients. Potential target genes of miR-638 were predicted and validated via multiple bioinformatics analyses.

RESULTS

miR-638 was upregulated in RCC tissues when compared with corresponding noncancerous tissues (P < 0.05). Upregulation of miR-638 expression by transfection with a synthetic miR-638 mimic promoted cell migration, invasion, and viability and suppressed cell apoptosis. Moreover, Kaplan-Meier analysis revealed that upregulation of miR-638 associated with shorter overall survival (OS; P = 0.001). Cox univariate and multivariate regression analysis suggested that miR-638 expression is an independent predictive factor for the prognosis of RCC patients (P = 0.004). KCNQ1, DNAJC6, and PNP were identified as potential target genes of miR-638.

CONCLUSIONS

The results of this study demonstrated that miR-638 functions as an oncogene in RCC and has the potential to be a prognostic biomarker for RCC.

Prognostic role of microRNAs in breast cancer: A systematic review

MicroRNAs (miRNAs) have been found to play an important role in breast cancer, functioning either as potential oncogenes or tumor suppressor genes, but their role in the prognosis of patients remains unclear. The aim of the present review study is to highlight recent preclinical and clinical studies performed on both circulating and tissue-specific miRNAs and their potential role as prognostic markers in breast cancer. We systematically searched the PubMed database to explore the prognostic value of miRNAs in breast cancer. After performing the literature search and review, 117 eligible studies were identified. We found that 110 aberrantly expressed miRNAs have been associated with prognosis in breast cancer. In conclusion, the collective data presented in this review indicate that miRNAs could serve as novel prognostic tools in breast cancer, while the clinical application of these findings has yet to be verified.

MicroRNAs in breast cancer: Roles, functions, and mechanism of actions

Breast cancer is one of the most lethal malignancies in women in the world. Various factors are involved in the development and promotion of the malignancy; most of them involve changes in the expression of certain genes, such as microRNAs (miRNAs). MiRNAs can regulate signaling pathways negatively or positively, thereby affecting tumorigenesis and various aspects of cancer progression, particularly breast cancer. Besides, accumulating data demonstrated that miRNAs are a novel tool for prognosis and diagnosis of breast cancer patients. Herein, we will review the roles of these RNA molecules in several important signaling pathways, such as transforming growth factor, Wnt, Notch, nuclear factor-κ B, phosphoinositide-3-kinase/Akt, and extracellular-signal-regulated kinase/mitogen activated protein kinase signaling pathways in breast cancer.

Protective potential of miR-146a-5p and its underlying molecular mechanism in diverse cancers: a comprehensive meta-analysis and bioinformatics analysis

Background/aims

Studies have shown that miR-146a-5p was differentially expressed in diverse cancers, but the associations between miR-146a-5p expression and prognosis across multiple types of cancer as well its potential targets and downstream pathways have not been comprehensively analyzed. In this study, we performed the first meta-analysis of the prognostic value of miR-146a-5p expression in diverse malignancies and explored prospective targets of miR-146a-5p and related signaling pathways.

Methods

A thorough search for articles related to miR-146a-5p was performed, and RNA-seq data from The Cancer Genome Atlas (TCGA) and microarray data from gene expression omnibus profiles were used to collect information about the prognostic value of miR-146a-5p. A comprehensive meta-analysis was conducted. Twelve platforms in miRWalk 2.0 were applied to predict targets of miR-146a-5p. TCGA RNA-seq data were used to validate the inverse relationships between miR-146a-5p and its likely targets. Subsequently, gene ontology and pathway analyses were conducted using Funrich version 3.1.3. Potential protein–protein interaction (PPI) networks were constructed. Potential target genes of miR-146a-5p in lung cancer were validated by RT-qPCR.

Results

We included 10 articles in the meta-analysis. In a pooled analysis, the high miR-146a-5p expression group showed a better overall survival in solid cancers, particularly in reproductive system cancers and digestive system cancers. A total of 120 predicted target genes were included in a bioinformatics analysis. Five pathways involving phospholipase C (PLC) and aquaporins (AQPs) were the most significantly enriched Kyoto Encyclopedia of Genes and Genomes pathways. Moreover, the PPI network displayed the related signaling pathways and interactions among proteins. AQP1 and FYN were validated by RT-qPCR to be potential targets of miR-146a-5p in lung cancer.

Conclusion

There is a close link between high miR-146a-5p expression and better overall survival in 21 types of solid cancer, especially in reproductive system and digestive system cancers. Furthermore, miR-146a-5p could inhibit diverse malignancies by modulating pathways linked to PLC or AQPs. In summary, miR-146a-5p is a potential prognostic biomarker and therapeutic target for various cancers.

Downregulation of miR-136 promotes the progression of osteosarcoma and is associated with the prognosis of patients with osteosarcoma

Osteosarcoma (OS) is the most common bone tumor in children and young adults, and is an aggressive tumor with poor prognosis. MicroRNAs (miRNAs) are aberrantly expressed in various types of cancer, and contribute to cancer tumorigenesis and progression. In the present study, the potential prognostic value and biological function of miRNA-136 (miR-136) in OS was investigated. Reverse transcription-quantitative polymerase chain reaction analysis was used to evaluate the expression of miR-136 in OS tissues and cell lines. Kaplan-Meier survival analysis and Cox regression analysis were conducted to investigate the prognostic significance of miR-136. Various in vitro cell based assays were used to evaluate the effects of miR-136 on the biological behavior of OS cells. A luciferase assay was performed to determine the key miR-136 targets associated with OS. The expression of miR-136 was significantly downregulated in osteosarcoma tissues and cells compared with the normal controls (all P<0.05). Decreased miR-136 expression was significantly associated with Enneking staging (P=0.030) and distant metastasis (P=0.016). Decreased miR-136 expression in patients was associated with shorter overall survival compared with patients with increased expression levels (log-rank test; P<0.05). The expression of miR-136 was indicated as an independent prognostic factor for the patients (hazard ratio=0.496; 95% confidence interval=0.250-0.987; P=0.046). MTT, transwell and Matrigel assays demonstrated that upregulation of miR-136 decreased proliferation, migration and invasion of OS cells. Bioinformatics and luciferase assays demonstrated that migration and invasion enhancer 1 (MIEN1) is a direct target of miR-136. Together, the results suggested that miR-136 functions as a tumor suppressor gene to regulate proliferation, migration and invasion of OS cells. MIEN1 was a potential target of miR-136. Additionally, miR-136 may serve as a prognostic biomarker for OS.

Downregulation of miR-638 promotes progression of breast cancer and is associated with prognosis of breast cancer patients

Background

Breast cancer is the most common tumor among women. miR-638 has been demonstrated to play an important role in various cancers.

Purpose

In this study, we aimed to investigate the function and prognostic value of miR-638 in breast cancer.

Methods

Quantitative real-time polymerase chain reaction analysis was used to evaluate the expression of miR-638 in breast cancer tissues and cell lines. The correlation of miR-638 with clinicopathological features was analyzed using the chi-squared test. Kaplan–Meier survival analysis and Cox regression assay were performed to investigate the prognostic value of miR-638 in breast cancer patients. The effects of miR-638 on the biological behavior of breast cancer cells were evaluated using functional assays.

Results

The expression of miR-638 was downregulated in breast cancer tissues and cell lines (all P<0.05). Decreased expression of miR-638 was significantly correlated with lymph node metastasis (P=0.015) and TNM stage (P=0.021). Patients with low miR-638 expression had shorter overall survival compared with those with high levels (Log-rank P=0.025). The miR-638 could be considered as an independent prognostic factor for the patients (HR =0.321, 95% CI =0.117–0.882, P=0.027). Downregulation of miR-638 was capable of promoting cell proliferation, migration, and invasion in MDA-MB-231 and MCF-7 cells.

Conclusion

All the results indicate that miR-638 is a tumor suppressor in breast cancer and is involved in the progression of breast cancer. Thus, it may serve as a prognostic biomarker for breast cancer.

CTBP1 and metabolic syndrome induce an mRNA and miRNA expression profile critical for breast cancer progression and metastasis

Metastatic breast cancer (BrCa) is still one of the main causes of cancer death in women. Metabolic syndrome (MeS), a risk factor for BrCa, is associated to high grade tumors, increased metastasis and recurrence of this disease. C-terminal binding protein 1 (CTBP1) is a co-repressor of tumor suppressor genes that is activated by low NAD⁺/NADH ratio. Previously, we demonstrated that CTBP1 hyperactivation by MeS increased tumor growth in MDA-MB-231-derived xenografts regulating several genes and miRNAs. In this work, our aim was to elucidate the role of CTBP1 and MeS in BrCa metastasis. We found that CTBP1 protein diminished adhesion while increased migration of triple negative BrCa cells. CTBP1 and MeS modulated the expression of multiple genes (ITGB4, ITGB6, PRSS2, COL17A1 and FABP4) and miRNAs (miR-378a-3p, miR-146a-5p, let-7e-3p, miR-381-5p, miR-194-5p, miR-494-3p) involved in BrCa progression of MDA-MB-231-derived xenografts. Furthermore, we demonstrated that MeS increased lung micrometastasis and liver neoplastic disease in mice. CTBP1 hyperactivation seems to be critical for MeS effect on BrCa metastasis since CTBP1 depletion completely impaired the detection of circulating tumor cells. Our results highlight CTBP1 and MeS impact on BrCa progression positioning them as key properties to be considered for BrCa patient prognosis and management.

MicroRNA-638 inhibits cell growth and tubule formation by suppressing VEGFA expression in human Ewing sarcoma cells

Ewing sarcoma (EWS) is a kind of aggressive tumor of bone and soft tissues, which most occurring in children and adolescents. MicroRNAs (miRNAs) perform essential function in the progression and development of EWS, while the putative role of miR-638 in EWS remains uncertain. Accordingly, we detected the expression of miR-638 and explored its putative biological effects on the malignant phenotype of EWS cells. As expected, miR-638 was significantly down-regulated in EWS cells. Moreover, overexpression of miR-638 suppressed cell growth, induced cell apoptosis, and inhibited tubule formation of EWS cells in vitro Among the putative target genes of miR-638 predicted by the miRNA target prediction tools, vascular endothelial cell growth factor A (VEGFA) attracted out attention most. The luciferase reporter assays reaffirmed that VEGFA was a targeted gene of miR-638 in EWS cells. Furthermore, miR-638 suppressed the mRNA and protein level of VEGFA, and restored the expression of VEGFA reversed the suppressed effects of miR-638 in EWS cells. Taken together, the results suggested that miR-638 might perform tumor suppressive effects in EWS, which might be mediated, at least partially, through suppressing the activity of VEGFA.

Both plasma and tumor tissue miR-146a high expression correlates with prolonged overall survival of surgical patients with intrahepatic cholangiocarcinoma

The purpose of this study was to investigate the association of tumor tissue and plasma miR-146a/b expressions with the clinicopathological properties and overall survival (OS) in surgical patients with intrahepatic cholangiocarcinomas (ICC).Eighty-seven patients with ICC were enrolled. Tumor tissue and plasma sample were collected and miR-146a/b expressions were assessed by quantitative polymerase chain reaction (qPCR). The median follow-up duration was 31 months, and the last follow-up date was January 2017.miR-146a (P < .001) and miR-146b (P = .006) expressions in tumor tissue were positively associated with that in plasma. Tissue miR-146a was negatively correlated with age (P = .036), poor differentiation (P = .020), N stage (P = .020), and TNM stage (P = .007), as well as ECOG performance (P = .008), whereas plasma miR-146a was inversely associated with N stage (P = .003), TNM stage (P = .003), and ECOG performance (P = .011). Moreover, tissue miR-146b was negatively correlated with gender (P = .043) and T stage (P = .047). Kaplan-Meier curves suggested that high expression of tissue miR-146a (P < .001) and plasma miR-146a (P = .029) were correlated with prolonged OS. Nevertheless, no association of miR-146b expression in tumor tissue (P = .187) and plasma (P = .336) with OS was discovered. Univariate analysis indicated that both tissue miR-146a (P < .001) and plasma miR-146a (P = .035) could predict better OS, whereas multivariate analysis revealed that only tissue miR-146a (P = .001) high expression was an independent factor for prolonged OS.Both plasma and tissue miR-146a expression correlated with favorable OS, whereas only tissue miR-146a was an independent prognostic biomarker in surgical patients with ICC.

The potential role of miRNAs in therapy of breast and ovarian cancers associated with BRCA1 mutation

Germline variants within BRCA1 or BRCA2 genes account for approximately 25% of familial aggregations of breast-ovarian cancers. Low or no expression of BRCA1 in breast and ovarian cancers is associated with a good clinical response to treatment with platinum therapies and PARP1 inhibitors. Recent studies demonstrated that microRNAs - small non-coding RNAs, involved in the control of gene expression, can decrease BRCA1 expression by targeting the 3’UTR region of the gene. This article reviews reported relationships between various miRNAs, such as miRNA-9, miRNA-146a, miRNA-182 miRNA-218, miRNA-638 and the response to cytostatic drugs, mainly to platins and PARP1 inhbitors, for the treatment of breast and ovarian cancer associated with BRCA1 mutations.

MicroRNA expression in bone marrow-derived human multipotent Stromal cells

Background

Multipotent stromal cells (MSCs) are being studied in the field of regenerative medicine for their multi-lineage differentiation and immunoregulatory capacity. MicroRNAs (miRNAs) are short non-coding RNAs that are responsible for regulating gene expression by targeting transcripts, which can impact MSC functions such as cellular proliferation, differentiation, migration and cell death. miRNAs are expressed in MSCs; however, the impact of miRNAs on cellular functions and donor variability is not well understood. Eight MSC lines were expanded to passages 3, 5 and 7, and their miRNA expression was evaluated using microarray technology.

Results

Statistical analyses of our data revealed that 71 miRNAs out of 939 examined were expressed by this set of MSC lines at all passages and the expression of 11 miRNAs were significantly different between passages 3 and 7, while the expression of 7 miRNAs was significantly different between passages 3 and 5. The expression of these identified miRNAs was evaluated using RT-qPCR for both the first set of MSC lines (n = 6) and a second set of MSC lines (n = 7) expanded from passages 4 to 8. By RT-qPCR only 2 miRNAs, miR-638 and miR-572 were upregulated at passage 7 compared to passage 3 in the first set of MSC lines by 1.71 and 1.54 fold, respectively; and upregulated at passage 8 compared to passage 4 in the second set of MSC lines, 1.35 and 1.59 fold, respectively.

Conclusions

The expression of miR-638 and miR-572 can distinguish MSCs from two different passages of cell culture. These results may be useful in establishing critical quality attributes of MSCs and determining whether changes in these two miRNAs impact cellular functions.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-017-3997-7) contains supplementary material, which is available to authorized users.

RNA-targeted therapeutics in cancer clinical trials: Current status and future directions

Recent advances in RNA delivery and target selection provide unprecedented opportunities for cancer treatment, especially for cancers that are particularly hard to treat with existing drugs. Small interfering RNAs, microRNAs, and antisense oligonucleotides are the most widely used strategies for silencing gene expression. In this review, we summarize how these approaches were used to develop drugs targeting RNA in human cells. Then, we review the current state of clinical trials of these agents for different types of cancer and outcomes from published data. Finally, we discuss lessons learned from completed studies and future directions for this class of drugs.

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