MicroRNA in breast cancer: The association with BRCA1/2

CircDENND2D Inhibits PD-L1-Mediated Non-Small Cell Lung Cancer Metastasis and Immune Escape by Regulating miR-130b-3p/STK11 Axis

Local recurrence and distant metastasis of non-small cell lung cancer (NSCLC) caused by immune escape is one of the root causes of treatment difficulties. We aim to investigate the mechanism of immune escape in NSCLC. NSCLC tissues were collected. Cell proliferation was detected by CCK-8 assay. Cell migration and invasion ability was measured by Transwell assay. The expressions of E-cadherin, N-cadherin and PD-L1 were detected by Western blot. NSCLC cells were co-cultured with CD8+ T cells to simulate tumor microenvironment in vitro. The proportion of CD8+ T cells and apoptosis were detected by flow cytometry. Dual-luciferase reporter gene assay confirmed the targeting relationship of circDENND2D and STK11. The expressions of circDENND2D and STK1 were down-regulated, while miR-130b-3p expression was up-regulated in NSCLC tissues. Overexpression of circDENND2D or STK11 inhibited NSCLC cells proliferation, migration and invasion, and attenuated the immune escape of NSCLC cells. CircDENND2D targeted miR-130b-3p to competitively promote STK11 expression. STK11 knockdown or miR-130b-3p overexpression attenuated the function of circDENND2D overexpression on NSCLC cells. CircDENND2D inhibited metastasis and immune escape of NSCLC by regulating miR-130b-3p/STK11 axis.

MicroRNA networks linked with BRCA1/2, PTEN, and common genes for Alzheimer's disease and breast cancer share highly enriched pathways that may unravel targets for the AD/BC comorbidity treatment

MicroRNAs (miRNAs) are involved in the regulation of various cellular processes including pathological conditions. MiRNA networks have been extensively researched in age-related degenerative diseases, such as cancer, Alzheimer's disease (AD), and heart failure. Thus, miRNA has been studied from different approaches, in vivo, in vitro, and in silico including miRNA networks. Networks linking diverse biomedical entities unveil information not readily observable by other means. This work focuses on biological networks related to Breast cancer susceptibility 1 (BRCA1) in AD and breast cancer (BC). Using various bioinformatics approaches, we identified subnetworks common to AD and BC that suggest they are linked. According to our results, miR-107 was identified as a potentially good candidate for both AD and BC treatment (targeting BRCA1/2 and PTEN in both diseases), accompanied by miR-146a and miR-17. The analysis also confirmed the involvement of the miR-17-92 cluster, and miR-124-3p, and highlighted the importance of poorly researched miRNAs such as mir-6785 mir-6127, mir-6870, or miR-8485. After filtering the in silico analysis results, we found 49 miRNA molecules that modulate the expression of at least five genes common to both BC and AD. Those 49 miRNAs regulate the expression of 122 genes in AD and 93 genes in BC, from which 26 genes are common genes for AD and BC involved in neuron differentiation and genesis, cell differentiation and migration, regulation of cell cycle, and cancer development. Additionally, the highly enriched pathway was associated with diabetic complications, pointing out possible interplay among molecules underlying BC, AD, and diabetes pathology.

Melodic maestros: Unraveling the role of miRNAs in the diagnosis, progression, and drug resistance of malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a highly lethal form of pleural cancer characterized by a scarcity of effective therapeutic interventions, resulting in unfavorable prognoses for afflicted individuals. Besides, many patients experience substantial consequences from being diagnosed in advanced stages. The available diagnostic, prognostic, and therapeutic options for MPM are restricted in scope. MicroRNAs (miRNAs) are a subset of small, noncoding RNA molecules that exert significant regulatory influence over several cellular processes within cell biology. A wide range of miRNAs have atypical expression patterns in cancer, serving specific functions as either tumor suppressors or oncomiRs. This review aims to collate, epitomize, and analyze the latest scholarly investigations on miRNAs that are believed to be implicated in the dysregulation leading to MPM. miRNAs are also discussed concerning their potential clinical usefulness as diagnostic and prognostic biomarkers for MPM. The future holds promising prospects for enhancing diagnostic, prognostic, and therapeutic modalities for MPM, with miRNAs emerging as a potential trigger for such advancements.

Immunomodulatory effects of one novel microRNA miR-63 in pearl oyster Pinctada fucata martensii

Novel microRNA miR-63 (novel-miR-63) from pearl oyster Pinctada fucata martensii (Pm-novel-miR-63) is a species-specific miRNA. Our previous research has shown that the expression of Pm-novel-miR-63 was significantly downregulated at 24 h after nucleus transplantation. In this study, we analyzed the function and regulatory role of Pm-novel-miR-63 in the immune response of pearl oysters. The results showed that Pm-novel-miR-63 expression increased after the stimulation of pathogen associated molecular patterns at 6-12 h, and the activity of immune and antioxidant enzymes in the serum decreased after Pm-novel-miR-63 overexpression. Transcriptome analysis revealed that Pm-novel-miR-63 participated in regulating transplantation immunity through the Notch and mRNA surveillance signaling pathways. Target prediction and dual luciferase analysis revealed that Pm-GDP-FucTP, Pm-CysLTR2, and Pm-RLR were the target genes of Pm-novel-miR-63. These results suggested that Pm-novel-miR-63 participated in regulating the immune response in pearl oysters and can serve as a new interference target to reasonably control excessive immune rejection in pearl culture.

Multifunctional hybrid nanoparticles in diagnosis and therapy of breast cancer

Breast cancer is the most prevalent non-cutaneous malignancy in women, with greater than a million new cases every year. In the last decennium, numerous diagnostic and treatment approaches have been enormously studied for Breast cancer. Among the different approaches, nanotechnology has appeared as a promising approach in preclinical and clinical studies for early diagnosis of primary tumors and metastases and eradicating tumor cells. Each of these nanocarriers has its particular advantages and drawbacks. Combining two or more than two constituents in a single nanocarrier system leads to the generation of novel multifunctional Hybrid Nanocarriers with improved structural and biological properties. These novel Hybrid Nanocarriers have the capability to overcome the drawbacks of individual constituents while having the advantages of those components. Various hybrid nanocarriers such as lipid polymer hybrid nanoparticles, inorganic hybrid nanoparticles, metal-organic hybrid nanoparticles, and hybrid carbon nanocarriers are utilized for the diagnosis and treatment of various cancers. Certainly, Hybrid Nanocarriers have the capability to encapsulate multiple cargos, targeting agents, enhancement in encapsulation, stability, circulation time, and structural disintegration compared to non-hybrid nanocarriers. Many studies have been conducted to investigate the utilization of Hybrid nanocarriers in breast cancer for imaging platforms, photothermal and photodynamic therapy, chemotherapy, gene therapy, and combinational therapy. In this review, we mainly discussed in detailed about of preparation techniques and toxicological considerations of hybrid nanoparticles. This review also discussed the role of hybrid nanocarriers as a diagnostic and therapeutic agent for the treatment of breast cancer along with alternative treatment approaches apart from chemotherapy including photothermal and photodynamic therapy, gene therapy, and combinational therapy.

Mitochondrial miRNAs (MitomiRs): Their potential roles in breast and other cancers

Breast cancer is the most common cancer in women worldwide. MicroRNAs (miRNAs) are non-coding RNAs that are involved in the post-transcriptional regulation of gene expression. Although miRNAs mainly act in the cytoplasm, they can be found in the mitochondrial compartment of the cell. These miRNAs called "MitomiR", they can change mitochondrial functions by regulating proteins at the mitochondrial level and cause cancer. In this review, we have aimed to explain miRNA biogenesis, transport pathways to mitochondria, and summarize mitomiRs that have been shown to play an important role in mitochondrial function, especially in the initiation and progression of breast cancer.

Circulating Exosomal microRNAs as Predictive Biomarkers of Neoadjuvant Chemotherapy Response in Breast Cancer

Background: Neoadjuvant chemotherapy (NACT) is an increasingly used approach for treatment of breast cancer. The pathological complete response (pCR) is considered a good predictor of disease-specific survival. This study investigated whether circulating exosomal microRNAs could predict pCR in breast cancer patients treated with NACT. Method: Plasma samples of 20 breast cancer patients treated with NACT were collected prior to and after the first cycle. RNA sequencing was used to determine microRNA profiling. The Cancer Genome Atlas (TCGA) was used to explore the expression patterns and survivability of the candidate miRNAs, and their potential targets based on the expression levels and copy number variation (CNV) data. Results: Three miRNAs before that NACT (miR-30b, miR-328 and miR-423) predicted pCR in all of the analyzed samples. Upregulation of miR-127 correlated with pCR in triple-negative breast cancer (TNBC). After the first NACT dose, pCR was predicted by exo-miR-141, while miR-34a, exo-miR182, and exo-miR-183 predicted non-pCR. A significant correlation between the candidate miRNAs and the overall survival, subtype, and metastasis in breast cancer, suggesting their potential role as predictive biomarkers of pCR. Conclusions: If the miRNAs identified in this study are validated in a large cohort of patients, they might serve as predictive non-invasive liquid biopsy biomarkers for monitoring pCR to NACT in breast cancer.

Analysis of inflammation-related microRNA expression in patients with ankylosing spondylitis

Ankylosing spondylitis (AS) is a complex genetic disease characterized by axial skeletal inflammation. Available scientific evidence suggests that a relationship may exist between miRNA expression levels and the pathogenesis of AS. This study investigated the clinical diagnostic value of miR-146a, miR-15a, miR-20a, miR-125a-3p, miR-125a-5p, miR-125b-5p, miR-148a, miR-149a, miR-499, and miR-155a in AS. A total of 44 AS patients and 56 healthy controls (HCs) were included in the study. MiRNA expression levels were detected using fluorescence quantitative PCR (qPCR). Results showed that the expression levels of miR-146a, miR-125a-3p, miR-125a-5p, miR-125b-5p, and miR-155a decreased, whereas miR-499a expression increased significantly in AS patients compared to that in the controls. Logistic regression analysis with receiver operating characteristic (ROC) curves showed that combined miR-146a/miR-125a-5p/miR-125b-5p/miR-499a/miR-155a (area under curve [AUC] = 0.824, 95% confidence interval [CI] = 0.727-0.921) had high sensitivity and specificity for AS diagnosis. C-reactive protein (CRP) levels were positively correlated with the expression of miR-125a-5p (r_s = 0.438, p = 0.005) and miR-155a (r_s = 0.414, p = 0.006), which indicates that miR-125a-5p and miR-155a can perhaps aggravate AS-induced inflammation. Our findings suggest the association of miR-125a-5p and miR-155a with disease activity in AS patients. Furthermore, miR-146a, miR-125a-5p, miR-125b-5p, miR-499a, and miR-155a could have potential diagnostic value in AS.

miR-522 regulates cell proliferation, migration, invasion capacities and acts as a potential biomarker to predict prognosis in triple-negative breast cancer

This study was designed to explore the cell functions and prognostic significance of miR-522 in triple-negative breast cancer. The expression levels of miR-522 in triple-negative breast cancer tissues and cell lines were detected by quantitative real-time PCR analysis. Kaplan-Meier curve and Cox regression analysis were used to investigate the relationship between miR-522 expression and prognosis of patients, and to evaluate the possibility of miR-522 as a potential indicator for predicting the prognosis of triple-negative breast cancer. The CCK-8 and transwell assays were used to assess cell proliferation, migration, and invasion abilities. The expression of miR-522 in triple-negative breast cancer tissues was significantly higher than that in adjacent tissues and its high expression was closely associated with the high incidence of lymph node metastasis, advanced TNM stage, and BRCA1/2 mutation status. High expression of miR-522 is correlated with poor overall survival in patients with triple-negative breast cancer. Besides, functional studies in two triple-negative breast cancer cell lines showed that overexpression of miR-522 significantly promoted cell proliferation, migration, and invasion in vitro. BRCA1 was a potential direct target of miR-522. Our findings indicated that miR-522 was highly expressed in triple-negative breast cancer and was associated with poor prognosis of patients. The upregulation of miR-522 accelerated the progression of triple-negative breast cancer by targeting BRCA1. Therefore, miR-522 provides valuable information for the development of prevention and treatment strategies.

Prognostic Value of miR-1826 in Prostate Cancer and Its Regulatory Effect on Tumor Progression

Purpose

miRNAs can act as oncogenes or tumor suppressors and participate in the development and progression of tumors, thus affecting the prognosis and survival of cancer patients. In this paper, we mainly studied the role of miR-1826 in prostate cancer.

Patients and Methods

The expression of miR-1826 was studied by quantitative real-time PCR (qRT-PCR). Kaplan–Meier curves were used to analyze the relationship between the expression of miR-1826 and the survival rate of PC patients. Cox regression analysis was used to study the risk factors affecting the prognosis of PC patients. PC cells were transfected with miR-1826 mimic, mimic negative control (mimic NC), miR-1826 inhibitor, or inhibitor NC. The effect of miR-1826 on the proliferation of PC cells was studied by the CCK-8 method and colony formation assay. Transwell assays were used to detect the effect of miR-1826 on the migratory and invasive abilities of tumor cells.

Results

The expression of miR-1826 in PC tissues was lower than that in adjacent normal tissues, and that the expression levels of miR-1826 in four PC cell lines were all lower than normal human prostate epithelial cell lines. Patients with low expression of miR-1826 had shorter overall survival compared with those with high expression. The downregulation of miR-1826 promoted PC cell proliferation, migration, and invasion.

Conclusion

In summary, the low expression of miR-1826 may promote the progression of PC, and the low expression of miR-1826 is also associated with a poor prognosis in PC patients.

AC092127.1-miR-451a-AE binding protein 2 Signaling Facilitates Malignant Properties of Breast Cancer

Purpose

The purpose of the current study was to explore the functions and potential mechanism of miR-451a in breast cancer (BC).

Methods

Quantitative reverse transcription real-time polymerase chain reaction was used to analyze the expression of miR-451a in human normal mammary cells (MCF-10A) and BC cells. Colony formation assay, terminal-deoxynucleoitidyl transferase mediated nick end labeling assay and transwell assays were conducted to validate the effect of miR-451a on proliferation, apoptosis, migration and invasion of BC cells, respectively. RNA pull-down, RNA immunoprecipitation and luciferase reporter assays were applied to investigate the upstream and downstream mechanisms of miR-451a in BC cells.

Results

MiR-451a was expressed at a low level in BC cells. Overexpression of miR-451a repressed BC cells proliferation, migration and invasion. Moreover, long non-coding RNA AC092127.1 acted as a sponge of miR-451a to enhance the expression level of AE binding protein 2 (AEBP2) that was demonstrated to be the target gene of miR-451a in BC cells. Finally, rescue experiments validated that miR-451a and AEBP2 involved in AC092127.1-mediated BC cell growth, migration and invasion.

Conclusion

In a word, AC092127.1/miR-451a/AEBP2 axis contributes to BC cell growth, migration and invasion. Our results may help to find novel potential targets for BC treatment.

CDX2 inducible microRNAs sustain colon cancer by targeting multiple DNA damage response pathway factors

Meta-analysis of transcripts in colon adenocarcinoma patient tissues led to the identification of a DNA damage responsive miR signature called DNA damage sensitive miRs (DDSMs). DDSMs were experimentally validated in the cancerous colon tissues obtained from an independent cohort of colon cancer patients and in multiple cellular systems with high levels of endogenous DNA damage. All the tested DDSMs were transcriptionally upregulated by a common intestine-specific transcription factor, CDX2. Reciprocally, DDSMs were repressed via the recruitment of HDAC1/2-containing complexes onto the CDX2 promoter. These miRs downregulated multiple key targets in the DNA damage response (DDR) pathway, namely BRCA1, ATM, Chk1 (also known as CHEK1) and RNF8. CDX2 directly regulated the DDSMs, which led to increased tumor volume and metastasis in multiple preclinical models. In colon cancer patient tissues, the DDSMs negatively correlated with BRCA1 levels, were associated with decreased probability of survival and thereby could be used as a prognostic biomarker. This article has an associated First Person interview with the first author of the paper.

microRNA-140-3p modulates invasiveness, motility, and extracellular matrix adhesion of breast cancer cells by targeting syndecan-4

Syndecan-4, a predicted target of the microRNA miR-140-3p, plays an important role in multiple steps of tumor progression and is the second most abundant heparan sulfate proteoglycan produced by breast carcinoma cell lines. To investigate the potential functional relationship of miR-140-3p and syndecan-4, MDA-MB-231, SKBR3, and MCF-7 breast cancer (BC) cells were transiently transfected with pre-miR-140-3p, syndecan-4 small interfering RNAJ, or control reagents, respectively. Altered cell behavior was monitored by adhesion, migration, and invasion chamber assays. Moreover, the prognostic value of syndecan-4 was assessed by Kaplan-Maier Plotter analysis of gene expression data from tumor samples of 4929 patients. High expression of syndecan-4 was associated with better relapse-free survival in the whole collective of BC patients, but correlated with a worse survival in the subgroup of estrogen receptor negative and estrogen/progesterone-receptor negative patients. miR-140-3p expression was associated with improved survival irrespective of hormone receptor status. miR-140-3p overexpression induced posttranscriptional downregulation of syndecan-4, as demonstrated by quantitative real-time PCR (qPCR), flow cytometry, and luciferase assays, resulting in decreased BC cell migration and matrigel invasiveness. Furthermore, miR-140-3p overexpression and syndecan-4 silencing increased the adhesion of BC to fibronectin and laminin. qPCR analysis demonstrated that syndecan-4 silencing leads to altered gene expression of adhesion-related molecules, such as fibronectin and focal adhesion kinase, as well as in the gene expression of the proinvasive factors matrix metalloproteinase 2 and heparanase (also known as HPSE). We conclude that syndecan-4 is a novel target of miR-140-3p that regulates BC cell invasiveness and cell-matrix interactions in the tumor microenvironment.

Breast Cancer Response to Therapy: Can microRNAs Lead the Way?

Breast cancer (BC) is a leading cause of death among women with malignant diseases. The selection of adequate therapies for highly invasive and metastatic BCs still represents a major challenge. Novel combinatorial therapeutic approaches are urgently required to enhance the efficiency of BC treatment. Recently, microRNAs (miRNAs) emerged as key regulators of the complex mechanisms that govern BC therapeutic resistance and susceptibility. In the present review we aim to critically examine how miRNAs influence BC response to therapies, or how to use miRNAs as a basis for new therapeutic approaches. We summarized recent findings in this rapidly evolving field, emphasizing the challenges still ahead for the successful implementation of miRNAs into BC treatment while providing insights for future BC management.The goal of this review was to propose miRNAs, that might simultaneously improve the efficacy of all four therapies that are the backbone of current BC management (radio-, chemo-, targeted, and hormone therapy). Among the described miRNAs, miR-21 and miR-16 emerged as the most promising, closely followed by miR-205, miR-451, miR-182, and miRNAs from the let-7 family. miR-21 inhibition might be the best choice for future improvement of invasive BC treatment.New therapeutic strategies of miRNA-based agents alongside current standard treatment modalities could greatly benefit BC patients. This review represents a guideline on how to navigate this elaborate puzzle.

MicroRNAs as biomarkers for breast cancer

Breast cancer is the most common type of cancer among women and the most frequent cause of death due to cancer among women. The lack of standard biomarkers in the early diagnosis of breast cancer, microRNAs (miRNA) have been of interest recently. Although, miRNAs are 19-24 nucleotide-long non-coding RNA species, they have crucial roles in many areas from organogenesis to carcinogenesis. This study has been conducted to investigate miR 21, miR 27b, miR 125a, miR 155, miR 200c, miR 335 miR373 as biomarkers in the early diagnosis of breast cancer; a selection based on the literature. Two miRNAs, miR 181 and miR 192 were selected as the endogenous control. MiRNAs were obtained from 5 cc blood samples taken from 20 breast cancer patients and 20 healthy people. 10 microRNAs were studied using Real Time PCR method. As a result, the quantities of miR 21, miR155 and miR125 ​​were significantly higher in the breast cancer group than in healthy controls. We suggest that performing validation studies in wider populations can help the use of miRNAs as biomarkers in the early diagnosis of breast cancer.

Regulatory MicroRNAs in T2DM and Breast Cancer

MicroRNAs orchestrate the tight regulation of numerous cellular processes and the deregulation in their activities has been implicated in many diseases, including diabetes and cancer. There is an increasing amount of epidemiological evidence associating diabetes, particularly type 2 diabetes mellitus, to an elevated risk of various cancer types, including breast cancer. However, little is yet known about the underlying molecular mechanisms and even less about the role miRNAs play in driving the tumorigenic potential of the cell signaling underlying diabetes pathogenesis. This article reviews the role of miRNA in bridging the diabetes–breast cancer association by discussing specific miRNAs that are implicated in diabetes and breast cancer and highlighting the overlap between the disease-specific regulatory miRNA networks to identify a 20-miRNA signature that is common to both diseases. Potential therapeutic targeting of these molecular players may help to alleviate the socioeconomic burden on public health that is imposed by the type 2 diabetes mellitus (T2DM)–breast cancer association.

miR-93 regulates liver tumor initiating cells expansion and predicts chemotherapeutic response of patients

Tumor initiating cells (T-ICs) play an important role in tumorigenesis, progression, metastasis, recurrence and drug resistance, but the underlying mechanism was not clearly elucidated. In our study, we found that miR-93 was highly expressed in liver T-ICs. Self-renewal and tumorigenesis ability of liver T-ICs were enhanced by miR-93 overexpression and attenuated by miR-93 interference. Mechanically, miR-93 regulated liver T-ICs by binding to 3'-UTR of myotubularin-related protein 3 (MTMR3). In addition, miR-93 was found highly expressed in cisplatin or sorafenib-resistant liver cancer tissues. Interference of miR-93 sensitizes hepatoma cells to cisplatin or sorafenib treatment. Clinical cohort analysis showed that Hepatocellular carcinoma (HCC) patients with low miR-93 were benefit more from TACE or sorafenib treatment. In conclusion, our study demonstrates a new regulation mechanism of liver T-ICs, a new target for HCC, and a biomarker for postoperative TACE or sorafenib.

Urinary Exosomal MicroRNAs as Potential Non-invasive Biomarkers in Breast Cancer Detection

INTRODUCTION

Breast cancer (BC) is the most frequent malignant disease in women worldwide and is therefore challenging for the healthcare system. Early BC detection remains a leading factor that improves overall outcome and disease management. Aside from established screening procedures, there is a constant demand for additional BC detection methods. Routine BC screening via non-invasive liquid biopsy biomarkers is one auspicious approach to either complete or even replace the current state-of-the-art diagnostics. The study explores the diagnostic potential of urinary exosomal microRNAs with specific BC biomarker characteristics to initiate the potential prospective application of non-invasive BC screening as routine practice.

METHODS

Based on a case-control study (69 BC vs. 40 healthy controls), expression level quantification and subsequent biostatistical computation of 13 urine-derived microRNAs were performed to evaluate their diagnostic relevance in BC.

RESULTS

Multilateral statistical assessment determined and repeatedly confirmed a specific panel of four urinary microRNA types (miR-424, miR-423, miR-660, and let7-i) as a highly specific combinatory biomarker tool discriminating BC patients from healthy controls, with 98.6% sensitivity and 100% specificity.

DISCUSSION

Urine-based BC diagnosis may be achieved through the analysis of distinct microRNA panels with proven biomarker abilities. Subject to further validation, the implementation of urinary BC detection in routine screening offers a promising non-invasive alternative in women's healthcare.

MicroRNA-598 inhibits the growth of triple negative breast cancer cells by targeting JAG1

Triple-negative breast cancer (TNBC) has an aggressive phenotype and a poor outcome. The discovery that dysregulated microRNAs (miRNAs) play an important role in tumor progression has led to the suggestion that miRNAs (miRs) could be a potential target for the treatment of TNBC. In the present study, it was demonstrated that miR-598 expression was significantly decreased in TNBC tissues and was related to the degree of lymph node metastasis of patients with TNBC. Ectopic expression of miR-598 suppressed viability and colony formation, as well as increased the apoptosis of TNBC cells. To further understand the functional mechanism of action underlying miR-598 in TNBC, targets of miR-598 were predicted with the miRDB bioinformatics tool. Jagged 1 (JAG1) was identified as a direct target of miR-598, possessing a binding site for miR-598 in its 3'-untranslated region. Overexpression of miR-598 inhibited the expression of JAG1 in TNBC cells. In addition, JAG1 was highly expressed in TNBC tissues and its expression was negatively correlated with the expression of miR-598. Overexpression of JAG1 significantly attenuated the inhibitory effects of miR-598 on the proliferation and colony formation of TNBC cells. Collectively, these results provided novel insights into the functional mechanism of action for the miR-598/JAG1 pathway in the development of TNBC.

Nanocomplexes loaded with miR-128-3p for enhancing chemotherapy effect of colorectal cancer through dual-targeting silence the activity of PI3K/AKT and MEK/ERK pathway

Although microRNAs (miRNAs)-based cancer therapy strategies have been proved to be efficient and superior to chemotherapeutic agents in certain extent, the unstable properties of miRNAs significantly impaired the wide application. Therefore, how to safely deliver the miRNAs to the targeted site of action is the most pivotal step to achieve the ideal treatment effect. In the present work, the miR-128-3p, which is able of inducing chromosomal instability, was loaded into the nanocomplexes developed by the PEG-PDMAEMA (PDMAEMA-NP). By this way, the miR-128-3p was shielded from exposure to various degrading enzymes in bloodstream. Additionally, the PEGylation endowed the PDMAEMA-NP with long time of circulation as demonstrated in vivo by pharmacokinetics investigation. To target and deliver the miR-128-3p to the site of action, a tumor-homing peptide CPKSNNGVC, which specifically targets the monocarboxylate transporter 1 (MCT1), was decorated on the surface of PDMAEMA-NP. Both in vitro and in vivo experiments demonstrated that more efficient delivery of miR-128-3p to cells or tumor tissues was obtained by the PDMAEMA-NP than plasmid. Additionally, modification of C peptides further enhanced the tumor accumulation of miR-128-3p, and in turn contributed to the stronger tumor growth inhibition effect. Underlying mechanisms study revealed that the miR-128-3p inhibited the growth, migration, and invasion of colorectal cancer (CRC) cells and progress of CRC tissues through silence of the activity of PI3K/AKT and MEK/ERK pathway. By this way, the chemotherapy effect of 5-Fluorouracil (5-Fu) was dramatically improved after co-treating the cells with miR-128-3p formulations.

miR-520b Inhibits IGF-1R to Increase Doxorubicin Sensitivity and Promote Cell Apoptosis in Breast Cancer

Doxorubicin (DOX) is currently one of the most widely used and effective drugs for the treatment of breast cancer, but drug resistance in breast cancer often leads to poor efficacy. MicroRNAs (miRNAs) are involved in the development and progression of various tumors and increasing number of studies have confirmed that abnormal miR-520b expression is closely associated breast cancer. We analyzed the clinical features, including miR-520b, of 30 patients with breast cancer. Further, we analyzed the interaction between miR-520b and insulin-like growth factor 1 receptor (IGF-1R) in breast cancer cell. miR-520b expression was significantly increased in chemotherapy-sensitive patients and was positively correlated with the chemotherapeutic efficacy in breast cancer. Cell proliferation assay confirmed that miR-520b promotes DOX-induced breast cancer cell apoptosis by regulating the PI3K/AKT signaling pathway. Moreover, bioinformatics method and dual luciferase reporter assay demonstrated that miR-520b negatively regulates IGF-1R, and IGF-1R overexpression and enhanced activity are closely associated with tumor development, progression, metastasis, and chemotherapy resistance. Similarly, cell proliferation assay showed that IGF-1R is negatively correlated with the efficacy of DOX chemotherapy and affects cell apoptosis mediated by the PI3K/AKT signaling pathway. On the contrary, miR-520b can downregulate the expression of IGF-1R. miR-520b increases DOX sensitivity and promotes cell apoptosis in breast cancer by inhibiting IGF-1R expression by the PI3K/AKT signaling pathway.

Association Between the miR-146a Rs2910164 Polymorphism and Childhood Acute Lymphoblastic Leukemia Susceptibility in an Asian Population

Background:miR-146a has been demonstrated to be involved in normal hematopoiesis and the pathogenesis of many hematological malignancies by inhibiting the expression of its targets. Rs2910164(G>C) may modify the expression of the miR-146a gene, which might influence an individual's predisposition to childhood acute lymphoblastic leukemia (ALL). However, inconsistent findings have been reported on the association between the rs2910164(G>C) polymorphism and the risk of childhood ALL.

Methods: A comprehensive meta-analysis was performed to accurately estimate the association between the miR-146a rs2910164 polymorphism and childhood ALL among four different genetic models.

Results: This meta-analysis included Asian studies with a total of 1,543 patients and 1,816 controls. We observed a significant difference between patients and controls for the additive model (CC vs. GG: OR = 1.598, 95% CI: 1.003–2.545, P = 0.049) using a random effects model. Meanwhile, there was a trend of increased childhood ALL risk in the dominant model (CC + CG vs. GG: OR = 1.501, 95% CI: 0.976–2.307, P = 0.065), recessive model (CC vs. GG + CG: OR = 1.142, 95% CI: 0.946–1.380, P = 0.168) and allele model (C vs. G: OR = 1.217, 95% CI: 0.987–1.500, P = 0.066) between patients and controls.

Conclusions: Our findings suggest that the miR-146a rs2910164 CC genotype was significantly associated with childhood ALL susceptibility.

Aberrant expression of microRNA-132-3p and microRNA-146a-5p in Parkinson's disease patients

Parkinson’s disease (PD) is an age-related neurodegenerative disorder which is assessed based on the motor symptoms. A number of microRNAs (miRNAs) are dysregulated and involved in the pathogenesis or development of PD. However, no confirmed markers are used for the early detection of PD. The present study aimed to elucidate the potential two miRNAs (miR-132-3p and miR-146-5p) as novel markers for early PD diagnosis. In the present study, the expression levels of miR-132-3p and miR-146-5p in serum samples from 82 patients with PD and 44 healthy volunteers were measured by reverse transcription-quantitative polymerase chain reaction. Furthermore, the correlation analysis was performed between aberrant miRNAs and Braak staging, Part V of the Unified Parkinson’s Disease Rating Scale (UPDRS-V; the modified Hoehn and Yahr staging of PD) and Part III of the UPDRS-III. Subsequently, the receiver–operating characteristic (ROC) curve results of miR-132-3p and miR-146-5p from healthy volunteers for PD prediction and from severe PD patients were assessed. From the results it was observed that miR-132-3p and miR-146a-5p expressions were significantly decreased in the serum samples of patients with PD compared to those in the healthy volunteers. Moreover, the expressions of miR-132-3p and miR-146a-5p showed a dramatic decrease in severe PD patients as compared to the normal PD patients. Meanwhile, miR-132-3p and miR-146-5p expressions were negatively correlated with Braak staging (r = −0.45, P < 0.0001; r = −0.51, P < 0.0001), UPDRS-III (r = −0.55, P < 0.0001; r = −0.51, P < 0.0001) and UPDRS-V scores (r = − 0.46, P < 0.0001; r = −0.45, P < 0.0001) in PD patients. The area under the curve (AUC) results of miR-132-3p and miR-146a-5p in discriminating PD patients from the healthy controls were 0.7325 (95% CI = 0.6400–0.8251) and 0.7295 (95% CI = 0.3658–0.8232). Moreover, the AUC results of miR-132-3p and miR-146-5p concerning discriminating severe PD patients from normal PD patients were 0.8175 (95% CI = 0.7229–0.9121) and 0.7921 (95% CI = 0.6937–0.8905). In other words, both miR-132-3p and miR-146a-5p may function as promising biomarkers for early diagnosis of PD.

Identification of colorectal cancers with defective DNA damage repair by immunohistochemical profiling of mismatch repair proteins, CDX2 and BRCA1

Colorectal cancer (CRC) is a complex disease as shown by consensus classification. The present study attempted to identify subtypes with known prognostic markers for better clinical management. A total of 72 CRC tumors were examined for the expression of mismatch repair (MMR) proteins, along with caudal-type homeobox protein 2 (CDX2) and BRCA1, by immunohistochemistry. Tumors were assigned based on the presence or loss of MMR proteins as proficient or deficient. Correlations were examined with CDX2 and BRCA1 along with clinico-pathological features. Expressional pattern of microRNAs (miRs/miRNAs), such as miR-183-96-182, known to be associated with defective DNA damage repair were evaluated by reverse transcription-quantitative PCR. A total of 22% of the CRC tumors were assigned as deficient in mismatch repair. 71% of the tumors expressed CDX2 while only 21% had nuclear expression of BRCA1. Loss of CDX2 protein was higher in the deficient subtype compared with the proficient subtype. A total of 14% of the tumors had dual loss of MMR and BRCA1 proteins and showed aggressive clinical features in addition to elevated expression of DNA damage repair microRNAs. The present study shows the presence of a small proportion of colorectal tumors with dual loss of key proteins involved in DNA damage repair which may be amenable to specific therapy. The implication of the present observations warrants investigation in a larger patient cohort with prognostic information.

The Regulatory Role of Mitochondrial MicroRNAs (MitomiRs) in Breast Cancer: Translational Implications Present and Future

Simple Summary

Mitochondrial microRNAs (mitomiRs) are an emerging field of study in a wide range of tumours including breast cancer. By targeting mitochondrial, or non-mitochondrial products, mitomiRs are able to regulate the functions of this organelle, thus controlling multiple carcinogenic processes. The knowledge of this system may provide a novel approach for targeted therapies, as potential biomarkers or helping in the diagnosis of such a complex malignancy.

Abstract

Breast cancer is the most prevalent and incident female neoplasm worldwide. Although survival rates have considerably improved, it is still the leading cause of cancer-related mortality in women. MicroRNAs are small non-coding RNA molecules that regulate the posttranscriptional expression of a wide variety of genes. Although it is usually located in the cytoplasm, several studies have detected a regulatory role of microRNAs in other cell compartments such as the nucleus or mitochondrion, known as “mitomiRs”. MitomiRs are essential modulators of mitochondrion tasks and their abnormal expression has been linked to the aetiology of several human diseases related to mitochondrial dysfunction, including breast cancer. This review aims to examine basic knowledge of the role of mitomiRs in breast cancer and discusses their prospects as biomarkers or therapeutic targets.

Circulating MicroRNAs as Prognostic and Therapeutic Biomarkers in Breast Cancer Molecular Subtypes

Breast cancer (BC) is a common and heterogeneous disease, of which six molecular subtypes, characterized by different biological features and clinical outcomes, were described. The identification of additional biomarkers able to further connote and distinguish the different BC subtypes is essential to improve the diagnostic, prognostic and therapeutic strategies in BC patients. MicroRNAs (miRNAs) are short non-coding RNA involved in several physiological and pathological processes, including cancer development and progression. In particular, circulating miRNAs, which can be found in an adequately stable structure in serum/plasma of cancer patients, are emerging as very promising non-invasive biomarkers. Several studies have analyzed the potential role of circulating miRNAs as prognostic and therapeutic markers in BC. In the present review we describe circulating miRNAs, identified as putative biomarker in BC, with special reference to different BC molecular subtypes.

miR-186 Represses Proliferation, Migration, Invasion, and EMT of Hepatocellular Carcinoma via Directly Targeting CDK6

The present study aimed to investigate the effect of miR-186 on proliferation, migration, invasion, and epithelialmesenchymal transition (EMT) of hepatocellular carcinoma (HCC). In this work, miR-186 was downregulated in HCC tissues and cells, and low miR-186 level helped predict the occurrence of vascular invasion and poor prognosis in patients with HCC. miR-186 overexpression inhibited cell proliferation and tumor growth in nude mice, repressed migration and invasion abilities, and enhanced apoptosis in HCC cells. miR-186 also retarded progression of EMT. miR-186 directly bound to the 3-untranslated regions of cyclin-dependent kinase 6 (CDK6) to inhibit its expression. Overexpression of CDK6 markedly reversed inhibitory effects of miR-186 on proliferation, apoptosis, migration, and invasion of HCC cells. Conversely, inhibition of CDK6 exerted synergic effect on the biological functions of miR-186. In conclusion, miR-186 represses proliferation, migration, invasion, and EMT, and induces apoptosis through targeting CDK6 in HCC, which may provide a new therapeutic target for HCC.

MicroRNAs, DNA damage response and ageing

Ageing is a multifactorial and integrated gradual deterioration affecting the most of biological process of cells. MiRNAs are differentially expressed in the cellular senescence and play important role in regulating of genes expression involved in features of ageing. The perception of miRNAs functions in ageing regulation can be useful in clarifying the mechanisms underlying ageing and designing of therapeutic strategies. The preservation of genomic integrity through DNA damage response (DDR) is related to the process of cellular senescence. The recent studies have shown that miRNAs has directly regulated the expression of numerous proteins in DDR pathways. In this review study, DDR pathways, miRNA biogenesis and functions, current finding on DDR regulations, molecular biology of ageing and the role of miRNAs in these processes have been studied. Finally, a brief explanation about the therapeutic function of miRNAs in ageing regarding its regulation of DDR has been provided.

miR-552 Regulates Liver Tumor-Initiating Cell Expansion and Sorafenib Resistance

MicroRNAs (miRNAs) are involved in tumorigenesis, progression, recurrence, and drug resistance of hepatocellular carcinoma (HCC). However, few miRNAs have been identified and entered clinical practice. Herein, we report that microRNA (miR)-552 is upregulated in HCC tissues and has an important function in liver tumor-initiating cells (T-ICs). Functional studies revealed that a forced expression of miR-552 promotes liver T-IC self-renewal and tumorigenesis. Conversely, miR-552 knockdown inhibits liver T-IC self-renewal and tumorigenesis. Mechanistically, miR-552 downregulates phosphatase and tensin homolog (PTEN) via its mRNA 3' UTR and activates protein kinase B (AKT) phosphorylation. Our clinical investigations elucidated the prognostic value of miR-552 in HCC patients. Furthermore, miR-552 expression determines the responses of hepatoma cells to sorafenib treatment. The analysis of patient cohorts and patient-derived xenografts (PDXs) further demonstrated that miR-552 may predict sorafenib benefits in HCC patients. In conclusion, our findings revealed the crucial role of the miR-552 in liver T-IC expansion and sorafenib response, rendering miR-552 an optimal target for the prevention and intervention in HCC.

MiR-214-3p regulates the viability, invasion, migration and EMT of TNBC cells by targeting ST6GAL1

MiR-214-3p is concerned with the outcomes of various tumors, such as liver cancer, bladder cancer, etc. However, the role and target of miR-214-3p in triple negative breast cancer (TNBC) is not fully understood. This study took this as the entry point, with a view to find a potential target for TNBC. The expressions of miR-214-3p in TNBC tissues and cell lines were detected, and the effects of miR-214-3p inhibitor on the viability, migration, invasion and epithelial mesenchymal transition (EMT) of TNBC cells were further analyzed. The potential target of miR-214-3p were predicted and verified, as well as the effects of target silencing on the TNBC cells were also measured. MiR-214-3p was abnormally elevated in both TNBC tissues and cell lines, especially in MDA-MB-468 cells. Low-expression of miR-214-3p restrained the survival, migration, invasion and EMT of TNBC cells. ST6GAL1 was the target gene of miR-214-3p, and its expression level increased with the low-expression of miR-214-3p. ST6GAL1 expression was abnormally reduced in both TNBC tissues and cell lines. The silence of ST6GAL1 promoted the viability, migration, invasion and EMT of TNBC cells, which could be reversed by miR-214-3p inhibitor. The down-regulation of miR-214-3p could suppress the viability, migration, invasion and EMT of TNBC cells though targeting ST6GAL1, which might be a potential target for future treatment of TNBC. Up-regulation of miR-214-3p could promote the EMT of non-TNBC cells.

Reversal of sorafenib resistance in hepatocellular carcinoma: epigenetically regulated disruption of 14-3-3η/hypoxia-inducible factor-1α

Sorafenib resistance is one of the main obstacles to the treatment of advanced/recurrent hepatocellular carcinoma (HCC). Here, sorafenib-resistant HCC cells and xenografts in nude mice were used as experimental models. A cohort of patients with advanced recurrent HCC who were receiving sorafenib therapy was used to assess the clinical significance of this therapy. Our data showed that 14-3-3η maintained sorafenib resistance in HCC. An analysis of the underlying molecular mechanisms revealed that 14-3-3η stabilizes hypoxia-inducible factor 1α (HIF-1α) through the inhibition of ubiquitin-dependent proteasome protein degradation, which leads to the maintenance of cancer stem cell (CSC) properties. We further found that microRNA-16 (miR-16) is a competent miRNA that reverses sorafenib resistance by targeting the 3'-UTR of 14-3-3η and thereby inhibits 14-3-3η/HIF-1α/CSC properties. In HCC patients, significant negative correlations were found between the expression of miR-16 and 14-3-3η, HIF-1α, or CSC properties. Further analysis showed that low miR-16 expression but high 14-3-3η expression can prognosticate sorafenib resistance and poor survival. Collectively, our present study indicated that miR-16/14-3-3η is involved in sorafenib resistance in HCC and that these two factors could be potential therapeutic targets and biomarkers for predicting the response to sorafenib treatment.

A genetic variant in miR-100 is a protective factor of childhood acute lymphoblastic leukemia

BACKGROUND

In the past decade, miR-100, miR-146a, and miR-210 were reported to be dysregulated in childhood acute lymphoblastic leukemia (ALL). However, effects of genetic variants in these three microRNAs have not been investigated in Chinese population.

METHODS

In this study, we conducted a case-control study to evaluate the relationship between genetic variants in miR-100, miR-146a, and miR-210 and the risk of childhood ALL in Chinese population. Subsequently, plasma expression level of miR-100 was also detected.

RESULT

We found that subjects carrying mutant homozygous TT genotype of miR-100 rs543412 had a statistically significantly decreased risk of childhood ALL (adjusted odds ratio [OR] = 0.73, 95% confidence interval [CI] = 0.55-0.97, P = 0.029). This protective effect was also observed among subjects whose parents were ever drinkers (adjusted OR = 0.53, 95% CI = 0.29-0.94), or whose living house were ever painted (adjusted OR = 0.57, 95% CI = 0.34-0.94). Besides, rs543412 variant homozygous TT had a significantly protective role in patients with childhood B-ALL. Finally, we found that expression level of miR-100 in plasma of childhood ALL cases was significantly higher than that of noncancer controls.

CONCLUSION

Our study suggested that there was significant association between the polymorphisms in miR-100 (rs543412) and decreased susceptibility to childhood ALL.

MiR-142-5p Acts as a Significant Regulator Through Promoting Proliferation, Invasion, and Migration in Breast Cancer Modulated by Targeting SORBS1

Background:

Numerous researches have demonstrated that miR-142-5p plays significant roles in several cancers, although the functional characteristic of miR-142-5p in breast cancer has not been determined. This study is designed to explore the biological significance of miR-142-5p in breast cancer clinical implication and mechanism of action.

Methods:

The differential expression patterns of miR-142-5p and Sorbin and SH3 domain-containing protein 1 and correlations between them and clinical significances were analyzed based on data from database. The expression levels of miR-142-5p in breast cancer cells were detected using quantitative real-time polymerase chain reaction. Cell counting kit-8, transwell, and wound healing assays were used to explore the potential functions of miR-142-5p in breast cancer cells. In addition, bioinformatics prediction analysis and luciferase reporter assay were utilized to predict and identify the potential target gene of miR-142-5p. A rescue experiment was conducted by transfecting miR-142-5p inhibitors and si-Sorbin and SH3 domain-containing protein 1 into cells to explore miR-142-5p/Sorbin and SH3 domain-containing protein 1 pairs on breast cancer cells behaviors.

Results:

The analysis results showed that miR-142-5p was highly expressed in patients with breast cancer, while Sorbin and SH3 domain-containing protein 1 presented a trend of low expression. The clinical significances analysis suggested that the overexpression of miR-142-5p is closely correlated with metastasis, while low expression of Sorbin and SH3 domain-containing protein 1 is correlated with clinicopathological characteristics and poor overall survival in patients with breast cancer. In vitro exploration, the expression of miR-142-5p was upregulated in breast cancer cells and inhibition of miR-142-5p expression significantly reduced the proliferation, invasion, and migration of breast cancer cells. Through rescue experiments, breast cancer cells proliferation, invasion, and migration reduction induced by silencing of miR-142-5p were reversed via knockdown Sorbin and SH3 domain-containing protein 1.

Conclusion:

Our findings insinuate that miR-142-5p functions as a positive regulator of promoting breast cancer cells biological behaviors and clinical metastasis, possibly regulated by targeting Sorbin and SH3 domain-containing protein 1, thus providing valuable information in the development of preventive or even therapeutic strategies for utilizing miR-142-5p as a promising target.

Tiny Yet Indispensable Plant MicroRNAs Are Worth to Explore as Key Components for Combating Genotoxic Stresses

Plants being sessile are always exposed to various stresses including biotic and abiotic stresses. Some of these stresses are genotoxic to cells causing DNA damage by forming lesions which include altered bases, cross-links, and breaking of DNA strands, which in turn hamper the genomic integrity. In order to survive through all these adverse conditions, plants have evolved different DNA repair mechanisms. As seen from the mammalian system and different human diseases, various microRNAs (miRNAs) can target the 3'-untranslated region of mRNAs that code for the proteins involved in DNA repair pathways. Since miRNAs play an important role in plant cells by regulating various metabolic pathways, it can also be possible that miRNAs play an important role in DNA repair pathways too. However, till date, only a handful of plant miRNAs have been identified to play important role in combating genotoxic stresses in plants. Limitation of information regarding involvement of miRNAs in DNA repair as well as in ROS scavenging prompted us to gather information about plant miRNAs specific for these tasks. This mini-review aims to present pertinent literature dealing with different genotoxic stresses that cause genome instability as well as plant specific responses to survive the damage. This is intertwined with the involvement of miRNAs in genotoxic stress in plants, challenges of applying miRNAs as a tool to combat DNA damage along with ways to overcome these challenges, and finally, the future prospective of these understudied aspects.

Characterisation of infection associated microRNA and protein cargo in extracellular vesicles of Theileria annulata infected leukocytes

The protozoan parasites Theileria annulata and Theileria parva are unique amongst intracellular eukaryotic pathogens as they induce a transformation-like phenotype in their bovine host cell. T. annulata causes tropical theileriosis, which is frequently fatal, with infected leukocytes becoming metastatic and forming foci in multiple organs resulting in destruction of the lymphoid system. Exosomes, a subset of extracellular vesicles (EV), are critical in metastatic progression in many cancers. Here, we characterised the cargo of EV from a control bovine lymphosarcoma cell line (BL20) and BL20 infected with T. annulata (TBL20) by comparative mass spectrometry and microRNA (miRNA) profiling (data available via ProteomeXchange, identifier PXD010713 and NCBI GEO, accession number GSE118456, respectively). Ingenuity pathway analysis that many infection-associated proteins essential to migration and extracellular matrix digestion were upregulated in EV from TBL20 cells compared with BL20 controls. An altered repertoire of host miRNA, many with known roles in tumour and/or infection biology, was also observed. Focusing on the tumour suppressor miRNA, bta-miR-181a and bta-miR-181b, we identified putative messenger RNA targets and confirmed the interaction of bta-miR181a with ICAM-1. We propose that EV and their miRNA cargo play an important role in the manipulation of the host cell phenotype and the pathobiology of Theileria infection.

Discovering lncRNA mediated sponge interactions in breast cancer molecular subtypes

BACKGROUND

Long non-coding RNAs (lncRNAs) can indirectly regulate mRNAs expression levels by sequestering microRNAs (miRNAs), and act as competing endogenous RNAs (ceRNAs) or as sponges. Previous studies identified lncRNA-mediated sponge interactions in various cancers including the breast cancer. However, breast cancer subtypes are quite distinct in terms of their molecular profiles; therefore, ceRNAs are expected to be subtype-specific as well.

RESULTS

To find lncRNA-mediated ceRNA interactions in breast cancer subtypes, we develop an integrative approach. We conduct partial correlation analysis and kernel independence tests on patient gene expression profiles and further refine the candidate interactions with miRNA target information. We find that although there are sponges common to multiple subtypes, there are also distinct subtype-specific interactions. Functional enrichment of mRNAs that participate in these interactions highlights distinct biological processes for different subtypes. Interestingly, some of the ceRNAs also reside in close proximity in the genome; for example, those involving HOX genes, HOTAIR, miR-196a-1 and miR-196a-2. We also discover subtype-specific sponge interactions with high prognostic potential. We found that patients differ significantly in their survival distributions if they are group based on the expression patterns of specific ceRNA interactions. However, it is not the case if the expression of individual RNAs participating in ceRNA is used.

CONCLUSION

These results can help shed light on subtype-specific mechanisms of breast cancer, and the methodology developed herein can help uncover sponges in other diseases.

Effects of miRNAs on functions of breast cancer stem cells and treatment of breast cancer

Breast cancer is one of the most common malignancies for women, which accounts for 30% of all female malignancies. The formation of breast cancer stem cells (BCSCs) is attributed to the acquisition of stemness of tumor cells. With self-renewal potential, these stem cells are insensitive to either radiotherapy or chemotherapy but are significant in regulating tumor behaviors and drug resistance. MicroRNA (miRNA) is a kind of noncoding small RNA for negatively regulating gene expressions. Research findings suggest that many miRNAs specifically regulate the expression of target genes and signal pathways of BCSCs. They play an important role in self-renewal, growth, and metastasis of breast cancer cells as potential targets for treating breast cancer. These signal pathways include phosphatase and tensin homolog deleted on chromosome 10-phosphatidylinositol 3-kinase/Akt, Wnt/β-catenin, Notch, and so on. This paper reviews the progress of research about miRNAs in self-renewal, metastasis, epithelial-mesenchymal transition and metastasis, mediation of resistance to chemotherapies, and treatment of breast cancer.

BRCA1 mutation spectrum, functions, and therapeutic strategies: The story so far

BRCA1 gene mutations account for about 25-28% of hereditary Breast Cancer as BRCA1 is included in the category of high penetrance genes. Except for few commonmutations, there is a heterogenous spectrum of BRCA1 mutations in various ethnic groups. 185AGdel and 5382ins Care the most common BRCA1 alterations (founder mutations) which have been identified in most of the population. This review has been compiled with an aim to consolidate the information on genetic variants reported in BRCA1 found in various ethnic groups, their functional implications if known; involvement of BRCA1 in various cellular pathways/processes and potential BRCA1 targeted therapies. The pathological variations of BRCA1 vary among different ethical groups. A systematic search in PubMed and Google scholar for the literature on BRCA1 gene was carried out to figure out structure and function of BRCA1 gene. BRCA1 is a large protein having 1863 amino acids with multiple functional domains and interacts with multiple proteins to carry out various crucial cellular processes. BRCA1 plays a major role in maintaining genome integrity, transcription regulation, chromatin remodeling, cell cycle checkpoint control, DNA damage repair, chromosomal segregation, and apoptosis. Studies investigating the phenotypic response of mutant BRCA1 protein and comparing it to wildtype BRCA1 protein are clinically important as they are involved in homologous recombination and other repair mechanisms. These studies may help in developing more targetted therapies, detecting novel interacting partners, identification of new signaling pathways that BRCA1 is a part of or downstream target genes that BRCA1 affects.