MicroRNA and Breast Cancer: Understanding Pathogenesis, Improving Management

Prognostic Value and Biological Role of miR-126 in Breast Cancer

In eukaryotic organisms such as humans, some noncoding single-stranded RNAs (ncRNAs) contribute to regulating the expression of some genes before and after the transcription process, which in turn controls a number of vital physiological processes, including cell proliferation, differentiation, invasion, angiogenesis, and embryonic development. miR-126 is one of these miRNAs expressed exclusively in endothelial cells such as capillaries and vessels involved in controlling angiogenesis. In recent years, the link between miRs such as miR-126 and the pathology of breast cancer has attracted the attention of many researchers. Numerous studies have shown that miR-126 may be able to suppress tumor tissue metastasis or to increase tumor metastasis through complex molecular mechanisms. There is ample clinical evidence that miR-126 can be used as a biomarker to predict and diagnose breast cancer due to the increased or decreased expression of certain genes in breast cancer tissue. In this review, we discuss the association between the growth and metastasis (tumorigenesis) of breast cancer and miR-126, as well as the relationship between current research advances in the prognosis, diagnosis, and treatment of breast cancer and miR-126.

Effect of microRNA-181b on the biological characteristics and clinical drug resistance of small-cell lung cancer by targeting angiotensin converting enzyme 2

Objective

To clarify the effect of miR‐181b on the biological function of small‐cell lung cancer (SCLC) and explore the effect of clinical resistance on SCLC.

Methods

Blood samples were collected from 30 SCLC patients and 30 non‐SCLC patients in our department from 2017 to 2019 to detect the expression level of miR‐181b.The expression level of miR‐181b was detected in SCLC cells by RT‐PCR, and screening of downstream target genes by gene chip, verification with luciferase, and Western blotting. In addition, collect the general data of 30 SCLC patients and 30 non‐SCLC patients (control group), the patients were diagnosed by pathology and undergoing EC protocol in the Department of Thoracic Surgery and Oncology of our hospital to detect the expression level of mir‐181b in different periods. Furthermore, in the SCLC cell line, EC chemotherapy was administered to detect the sensitivity of drug resistance and nondrug resistance.

Results

miR‐181b in SCLC patients was lower than in normal people as well as the drug‐sensitive cell line. ACE2 was verified as a downstream target of miR‐181b by gene chip screening. First‐line chemotherapy can promote the recovery of miR‐181b, but cannot repair to normal levels. miR‐181b can enhance the drug sensitivity of SCLC drug‐resistant cells.

Conclusion

miR‐181b directly targets ACE2 to affect the biological characteristics of SCLC. The expression level of miR‐181b is highly related to the drug resistance of SCLC, which suggests that miR‐181b could be a potential biomarker candidate for treatment efficacy of SCLC.

Evaluation of miR-34a Effect on CCND1 mRNA Level and Sensitization of Breast Cancer Cell Lines to Paclitaxel

Background

A growing body of literature has revealed the effective role of miR-34a, as a tumor suppressor and regulator of expression of multiple targets in tumorigenesis and cancer progression. This study aimed at evaluating the potential effects of miR-34a alone or in combination with paclitaxel on breast cancer cells.

Methods

After miR-34a transduction by lentiviral vectors in two MCF-7 and MDA-MB-231 cell lines of breast cancer, effects of the elevated expression of miR-34a in the cell viability and the cell proliferation were determined using MTT assay in treated and untreated cells with paclitaxel. The mRNA level of the CCND1 (Cyclin D1)gene was then measured in the two cell lines using the qRT-PCR assay. Finally, the influence of miR-34a and paclitaxel on apoptosis and cell cycle progression were examined by flow cytometry.

Results

The CCND1 mRNA expression levels were significantly down-regulated by overexpressed lentiviral miR-34a in MCF-7 and MDA-MB-231 cells. Combined treatment by miR-34a and paclitaxel reduced the cell viability and proliferation compared to single-drug treatment. In addition, the cell cycle arrest appeared at two phases by the combination of miR-34a and paclitaxel in MDA-MB-231 cells.

Conclusion

Our results suggest that miR34a, in combination with paclitaxel, has a potential for decreasing the cell viability and proliferation. Moreover, it can reduce the expression of CCND1 mRNA independent of the paclitaxel effect.

The extensive role of miR-155 in malignant and non-malignant diseases

MicroRNAs (miRNAs) have rapidly emerged as key molecules in cancer initiation and development, showing the capability to regulate pivotal oncogenic pathways. MiR-155 has gathered an increased attention especially in oncology, but also in non-malignanat pathologies. Nowadays, this noncoding RNA is one of the most important miRNAs in cancer, due to the extensive signaling network associated with it, implication in immune system regulation and also deregulation in disease states. Therefore, numerous research protocols are focused on preclinical modulation of miR-155 for therapeutic purposes, or investigation of its dynamic expression for diagnostic/prognostic assessments, with the final intention of bringing this miRNA into the clinical setting. This review comprehensively presents the extended role of miR-155 in cancer and other pathologies, where its expression is dysregulated. Finally, we assess the future steps toward miR-155 based therapeutics.

miR-181a/b therapy in lung cancer: reality or myth?

Despite substantial progress in oncology, lung cancer remains the number one malignancy in terms of both incidence and mortality rates, and there thus remains an urgent need for new therapeutic alternatives. MicroRNA (miRNA) have an important role in cancer initiation and progression due to their capacity to interfere with transcriptional signaling and regulate key cellular processes. miR-181a and miR-181b (miR-181a/b), which are located on chromosomes 1 and 9, are pathologically expressed in the tumor tissue and plasma of patients diagnosed with lung cancer. The miR-181a/b regulatory mechanisms are sophisticated and are directly related to different target genes. In recent years, an ever-increasing number of studies have focused on the biological relevance of miR-181a/b in key cellular processes. In this paper, we aim to discuss the challenging experimental data related to miR-181a/b and their potential use for the development of new therapeutic approaches in lung cancer. We will further present the ongoing issues regarding the regulation of their multiple target genes, and their potential use as biomarkers and therapeutic targets in this deadly malignancy.

Aberrant miRNAs expressed in HER-2 negative breast cancers patient

Background

Breast cancer is a highly heterogeneous pathology, exhibiting a number of subtypes commonly associated with a poor outcome. Due to their high stability, microRNAs are often regarded as non-invasive cancer biomarkers, having an expression pattern specific for their ‘cell of origin’.

Method

Triple negative breast cancer (TNBC: ER-, PR-, Her-2-) and double positive breast cancer (DPBC: ER+, PR+, Her-2) miRNA expression patterns were obtained by analysis of the TCGA (The Cancer Genome Atlas) data, followed by PCR-array analysis on plasma samples from 20 TNBC patients, 14 DPBC patients and 11 controls.

Results

Three downregulated and nine upregulated miRNAs were obtained from the TNBC analysis. Five overexpressed miRNAs were identified in the DPBC group. Four of the dysregulated miRNAs (miR-10a, miR-125b, miR-210 and miR-489) were common for both groups. The cluster miR-17-92 (miR-17, miR-20a, miR-20b, and miR-93), along with miR-130, miR-22 and miR-29a/c, were found to differentiate between TNBC and DPBC. A panel of five transcripts (miR-10a, miR-125, miR-193b, miR-200b and miR-489) was validated in a new set of plasma samples. The overlapping of TCGA and plasma profiling data revealed miR-200b, miR-200c, miR-210 and miR-29c as common signature. MiR-200b was validated on additional normal and tumor tissue samples. The expression level of this transcript from the TCGA data was correlated with lung and bone metastatic genes.

Conclusion

The miR-200b presents a great potential for the future advancements in the diagnostic/prognostic and therapeutic approach of TNBC, along with other coding or non-coding transcripts. However, this needs to be further integrated in a regulatory network that acts in conjunction with other markers that affect the patients’ prognosis or response to therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-018-0920-2) contains supplementary material, which is available to authorized users.

An approach toward miRNA detection via different thermo-responsive aggregation/disaggregation of CdTe quantum dots

A novel and “light shift” spectral method for the detection of miRNA based on different thermal-responsive aggregation/disaggregation of CdTe quantum dots was investigated.

The roles of oncogenic miRNAs and their therapeutic importance in breast cancer

Since the discovery of tumour suppressive miRNA in 2002, the dysregulation of miRNAs was implicated in many cancers, exhibiting both tumour suppressive and oncogenic roles. Dysregulation of miRNAs was found to be involved in the initiation of oncogenesis, as well as the progression, invasion and metastasis of cancers. While normal miRNA inhibitory functions help regulate gene expression in the cell, oncogenic miRNA, when dysregulated can lead to suppression of critical pathways that control apoptosis, cell cycle progression, growth and proliferation. This suppression allows for the upregulation of pro-oncogenic factors that drive cell survival, growth and proliferation. Due to emerging discoveries, oncogenic miRNAs are proving to be a critical component in cancers, such as breast cancer, and may provide novel avenues for cancer treatment. In this article, we discuss the roles of the most studied oncogenic miRNAs in breast cancer including clusters and families involved as well as the less studied and recently discovered oncogenic miRNAs. These miRNAs provide valuable information into the complexity of regulatory elements affected by their overexpression and the overall impact in the progression of breast cancer. Also, identifying miRNAs causing or leading to resistance or sensitivity to current anti-cancer drugs prior to treatment may lead to an improvement in treatment selection and overall patient response. This review summarizes known and recently discovered miRNAs in literature found to have oncogenic roles in breast cancer initiation and the progression, invasion and metastasis of the disease.

Combining Anti-Mir-155 with Chemotherapy for the Treatment of Lung Cancers

Purpose: The oncogenic miR-155 is upregulated in many human cancers, and its expression is increased in more aggressive and therapy-resistant tumors, but the molecular mechanisms underlying miR-155-induced therapy resistance are not fully understood. The main objectives of this study were to determine the role of miR-155 in resistance to chemotherapy and to evaluate anti-miR-155 treatment to chemosensitize tumors.Experimental Design: We performed in vitro studies on cell lines to investigate the role of miR-155 in therapy resistance. To assess the effects of miR-155 inhibition on chemoresistance, we used an in vivo orthotopic lung cancer model of athymic nude mice, which we treated with anti-miR-155 alone or in combination with chemotherapy. To analyze the association of miR-155 expression and the combination of miR-155 and TP53 expression with cancer survival, we studied 956 patients with lung cancer, chronic lymphocytic leukemia, and acute lymphoblastic leukemia.Results: We demonstrate that miR-155 induces resistance to multiple chemotherapeutic agents in vitro, and that downregulation of miR-155 successfully resensitizes tumors to chemotherapy in vivo We show that anti-miR-155-DOPC can be considered non-toxic in vivo We further demonstrate that miR-155 and TP53 are linked in a negative feedback mechanism and that a combination of high expression of miR-155 and low expression of TP53 is significantly associated with shorter survival in lung cancer.Conclusions: Our findings support the existence of an miR-155/TP53 feedback loop, which is involved in resistance to chemotherapy and which can be specifically targeted to overcome drug resistance, an important cause of cancer-related death. Clin Cancer Res; 23(11); 2891-904. ©2016 AACR.

Recent trends in microRNA research into breast cancer with particular focus on the associations between microRNAs and intrinsic subtypes

MicroRNAs (miRNAs) are short non-coding RNAs that regulate the function of target genes at the post-transcriptional phase. miRNAs are considered to have roles in the development, progression and metastasis of cancer. Recent studies have indicated that particular miRNA signatures are correlated with tumor aggressiveness, response to drug therapy and patient outcome in breast cancer. On the other hand, in routine clinical practice, the treatment regimens for breast cancer are determined based on the intrinsic subtype of the primary tumor. Previous studies have shown that miRNA expression profiles of each intrinsic subtypes of breast cancer differ. In hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer, miRNA expressions are found to be correlated with endocrine therapy resistance, progesterone receptor expression and heat shock protein activity. Some miRNAs are associated with resistance to HER2-targeted therapy and HER3 expression in HER2-positive breast cancer. In triple-negative breast cancer, miRNA expressions are found to be associated with BRCA mutations, immune system, epithelial-mesenchymal transition, cancer stem cell properties and androgen receptor expression. As it has been clarified that the expression levels and functions of miRNA differ among the various subtypes of breast cancer, and it is necessary to take account of the characteristics of each breast cancer subtype during research into the roles of miRNA in breast cancer. In addition, the discovery of the roles played by miRNAs in breast cancer might provide new opportunities for the development of novel strategies for diagnosing and treating breast cancer.

Export of microRNAs: A Bridge between Breast Carcinoma and Their Neighboring Cells

Breast cancer is a leading type of cancer among women in India as well as worldwide. According to the WHO 2015 report, it has been anticipated that there would be a twofold rise in the death due to breast cancer among women. The heterogeneous property of breast carcinoma has been suggested to be linked with dedicated set of communication and signaling pathway with their surroundings, which culminate into progression and development of the cancer. Among the plethora of communication tools in the hand of breast carcinoma cells is the recently appreciated exocytosis of the tightly packed short non-coding RNA molecules, predominantly the microRNAs (miRNAs). Recent studies suggest that miRNAs may work as courier messengers to participate in endocrine and paracrine signaling to facilitate information transfer between breast carcinoma and their neighboring cells. Evidence suggests that breast tumor cells communicate via packaged miRNAs in the tumor-released microvesicles, which enrich the tumor microenvironment. There is a strong view that dissecting out the mechanistic and regulatory aspects of miRNA export and role may uncover many prospects for overcoming the signaling defects and thereby controlling aberrant cell division. The detection of circulating miRNAs associated with breast carcinoma can also be used as biomarkers for early diagnosis. This review article is an attempt to provide updated knowledge on implications of short RNAs and their transport in the breast cancer pathophysiology.