Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

Dr. Jekyll or Mr. Hyde: The multifaceted roles of miR-145-5p in human health and disease

MicroRNAs (miRNAs) are classified as small, non-coding RNAs that play crucial roles in diverse biological processes, including cellular development, differentiation, growth, and metabolism. MiRNAs regulate gene expression by recognizing complementary sequences within messenger RNA (mRNA) molecules. Recent studies have revealed that miR-145-5p functions as a tumor suppressor in several cancers, including lung, liver, and breast cancers. Notably, miR-145-5p plays a vital role in the pathophysiology underlying HIV and chronic obstructive pulmonary diseases associated with cigarette smoke. This miRNA is abundant in biofluids and shows potential as a biomarker for the diagnosis and prognosis of several infectious diseases, such as hepatitis B, tuberculosis, and influenza. Additionally, numerous studies have indicated that other non-coding RNAs, including long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), can regulate miR-145-5p. Given the significance of miR-145-5p, a comprehensive overview focusing on its roles in health and disease is essential. This review discusses the dual role of miR-145-5p as a protagonist and antagonist in important human diseases, with particular emphasis on disorders of the respiratory, digestive, nervous, reproductive, endocrine, and urinary systems.

MicroRNAs as behind-the-scenes molecules in breast cancer metastasis and their therapeutic role through novel microRNA-based delivery strategies

Breast cancer is the primary cause of cancer-related death and the most frequent malignancy among women in Western countries. Although there have been advancements in combination treatments and targeted therapies for the metastatic diseases management, metastatic breast cancer is still the second most common cause of cancer-related deaths among U.S. women. The routes of metastasis encompass invasion, intravasation, circulation, extravasation, infiltration into a remote location to establish a metastatic niche, and the formation of micro-metastases in a new environment. Each of these processes is regulated by changes in gene expression. MicroRNAs (miRNAs) are widely expressed by a variety of organisms and have a key role in cell activities including suppressing or promoting cancer through regulating various pathways. Target gene expression is post-transcriptionally regulated by miRNAs, which contribute to the development, spread, and metastasis of breast cancer. In this study, we comprehensively discussed the role of miRNAs as predictors of breast cancer metastasis, their correlation with the spread of the disease to certain organs, and their potential application as targets for breast cancer treatment. We also provided molecular mechanisms of miRNAs in the progression of breast cancer, as well as current challenges in miRNA-based therapeutic approaches. Furthermore, as one of the primary issues with the treatment of solid malignancies is the efficient delivery of miRNAs, we examined a number of cutting-edge carriers for miRNA-based therapies and CRISPR/Cas9 as a targeted therapy for breast cancer.

Mapping the function of MicroRNAs as a critical regulator of tumor-immune cell communication in breast cancer and potential treatment strategies

Among women, breast cancer ranks as the most prevalent form of cancer, and the presence of metastases significantly reduces prognosis and diminishes overall survival rates. Gaining insights into the biological mechanisms governing the conversion of cancer cells, their subsequent spread to other areas of the body, and the immune system's monitoring of tumor growth will contribute to the advancement of more efficient and targeted therapies. MicroRNAs (miRNAs) play a critical role in the interaction between tumor cells and immune cells, facilitating tumor cells' evasion of the immune system and promoting cancer progression. Additionally, miRNAs also influence metastasis formation, including the establishment of metastatic sites and the transformation of tumor cells into migratory phenotypes. Specifically, dysregulated expression of these genes has been associated with abnormal expression of oncogenes and tumor suppressor genes, thereby facilitating tumor development. This study aims to provide a concise overview of the significance and function of miRNAs in breast cancer, focusing on their involvement as tumor suppressors in the antitumor immune response and as oncogenes in metastasis formation. Furthermore, miRNAs hold tremendous potential as targets for gene therapy due to their ability to modulate specific pathways that can either promote or suppress carcinogenesis. This perspective highlights the latest strategies developed for miRNA-based therapies.

Inhibition of MiR-155 Using Exosomal Delivery of Antagomir Can Up-Regulate PTEN in Triple Negative Breast Cancer

BACKGROUND

The most aggressive form of breast cancer (BC) is Triple-Negative BC (TNBC), with the poorest prognosis, accounting for nearly 15% of all cases. Since there is no effective treatment, novel strategies, especially targeted therapies, are essential to treat TNBC. Exosomes are nano-sized microvesicles derived from cells and transport various intracellular cargoes, including microRNAs (miRNAs). MiRNAs, small non-coding RNA, are an influential factor in the development of cancerous transformations in cells.

METHOD

Bioinformatics analysis of genes related to TNBC revealed that PTEN plays a crucial role in the disease. Relative expression of this gene was analyzed with RT-qPCR in 14 TNBC clinical samples. Electroporation was used to load miRNA antagomir into exosomes extracted from the conditioned medium. Then, the expression of miR-155 and PTEN was evaluated in MDA-MB-231 cells treated with antagomir-loaded exosomes.

RESULTS

Based on the bioinformatics analysis, miR-155 is a potent inhibitor of PTEN. Following treatment with antagomir-loaded exosomes, RT-qPCR showed significantly reduced miR- 155 and increased PTEN levels in MDA-MB-231 cells.

CONCLUSION

Based on the results of this study, exosomes can be effectively used as a cargo of oligonucleotides like miRNA mimics and antagomirs in targeted therapies.

MicroRNA (miR)-124: A Promising Therapeutic Gateway for Oncology

MicroRNA (miR) are a class of small non-coding RNA that are involved in post-transcriptional gene regulation. Altered expression of miR has been associated with several pathological conditions. MicroRNA-124 (miR-124) is an abundantly expressed miR in the brain as well as the thymus, lymph nodes, bone marrow, and peripheral blood mono-nuclear cells. It plays a key role in the regulation of the host immune system. Emerging studies show that dysregulated expression of miR-124 is a hallmark in several cancer types and it has been attributed to the progression of these malignancies. In this review, we present a comprehensive summary of the role of miR-124 as a promising therapeutic gateway in oncology.

An insight into the associations between microRNA expression and mitochondrial functions in cancer cell and cancer stem cell

The self-renew ability of cancer stem cells (CSCs) continues to challenge our determination for accomplishing cancer therapy breakthrough. Ineffectiveness of current cancer therapies to eradicate CSCs has contributed to chemoresistance and tumor recurrence. Yet, the discoveries of highly effective therapies have not been thoroughly developed. Further insights into cancer metabolomics and gene-regulated mechanisms of mitochondria in CSCs can expedite the development of novel anticancer drugs. In cancer cells, the metabolism is reprogrammed from oxidative phosphorylation (OXPHOS) to glycolysis. This alteration allows the cancer cell to receive continuous energy supplies and avoid apoptosis. The pyruvate obtained from glycolysis produces acetyl-coenzyme A (Acetyl-CoA) via oxidative decarboxylation and enters the tricarboxylic acid cycle for adenosine triphosphate generation. Mitochondrial calcium ion (Ca²⁺) uptake is responsible for mitochondrial physiology regulation, and reduced uptake of Ca²⁺  inhibits apoptosis and enhances cell survival in cancer. There have been many discoveries of mitochondria-associated microRNAs (miRNAs) stimulating the metabolic alterations in mitochondria via gene regulation which promote cancer cell survival. These miRNAs are also found in CSCs where they regulate genes and activate different mechanisms to destroy the mitochondria and enhance CSCs survival. By targeting the miRNAs that induced mitochondrial destruction, the mitochondrial functions can be restored; thus, it triggers CSCs apoptosis and completely eliminates the CSCs. In general, this review article aims to address the associations between miRNAs with mitochondrial activities in cancer cells and cancer stem cells that support cancer cell survival and self-renewal.

MiR-182-3p targets TRF2 and impairs tumor growth of triple-negative breast cancer

The telomeric repeat-binding factor 2 (TRF2) is a telomere-capping protein that plays a key role in the maintenance of telomere structure and function. It is highly expressed in different cancer types, and it contributes to cancer progression. To date, anti-cancer strategies to target TRF2 remain a challenge. Here, we developed a miRNA-based approach to reduce TRF2 expression. By performing a high-throughput luciferase screening of 54 candidate miRNAs, we identified miR-182-3p as a specific and efficient post-transcriptional regulator of TRF2. Ectopic expression of miR-182-3p drastically reduced TRF2 protein levels in a panel of telomerase- or alternative lengthening of telomeres (ALT)-positive cancer cell lines. Moreover, miR-182-3p induced DNA damage at telomeric and pericentromeric sites, eventually leading to strong apoptosis activation. We also observed that treatment with lipid nanoparticles (LNPs) containing miR-182-3p impaired tumor growth in triple-negative breast cancer (TNBC) models, including patient-derived tumor xenografts (PDTXs), without affecting mouse survival or tissue function. Finally, LNPs-miR-182-3p were able to cross the blood-brain barrier and reduce intracranial tumors representing a possible therapeutic option for metastatic brain lesions.

Curcumin alters distinct molecular pathways in breast cancer subtypes revealed by integrated miRNA/mRNA expression analysis

BACKGROUND

Curcumin is well known for its anticancer properties. Its cytotoxic activity has been documented in several cancer cell lines, including breast cancer. The pleiotropic activity of curcumin as an antioxidant, an antiangiogenic, antiproliferative, and pro-apoptotic, is due to its diverse targets, such as signaling pathways, protein/enzyme, or noncoding gene.

AIM

This study aimed to identify key miRNAs and mRNAs induced by curcumin in breast cancer cells MCF7, T47D (hormone positive), versus MDA-MB231 (hormone negative) using comparative analysis of global gene expression profiles.

METHODS

RNA was isolated and subjected to mRNA and miRNA library sequencing to study the global gene expression profile of curcumin-treated breast cancer cells. The differential expression of gene and miRNA was performed using the DESeq R package. The enriched pathways were studied using cluster profileR, and integrated miRNA-mRNA analysis was carried out using miRtarvis and miRmapper tools.

RESULTS

Curcumin treatment led to upregulation of 59% TSGs in MCF7, 21% in MDA-MB-231 cells, and 36% TSGs in T47D, and downregulation of 57% oncogenes in MCF7, 76% in MDA-MB-231, and 91% in T47D. Similarly, curcumin treatment led to upregulation of 32% TSmiRs in MCF7, 37.5% in MDA-MB231, and 62.5% in T47D, and downregulation of 77% oncomiRs in MCF7, 50% in MDA-MB231 and 28.6% in T47D. Integrated analysis of miRNA-mRNA led to the identification of a common NFKB pathway altered by curcumin in all three cell lines. Analysis of uniquely enriched pathway revealed non-integrin membrane-ECM interactions and laminin interactions in MCF7; extracellular matrix organization and degradation in MDA-MB-231 and cell cycle arrest and G2/M transition in T47D.

CONCLUSION

Curcumin regulates miRNA and mRNA in a cell type-specific manner. The integrative analysis led to the detection of miRNAs and mRNAs pairs, which can be used as biomarkers associated with carcinogenesis, diagnostic, and treatment response in breast cancer.

Could inhibition of metalloproteinases be used to block the process of metastasis?

Metastasis is a multisequential process that allows tumor cells to migrate to tissues distant from the primary tumor. Only a small number of cells escape from the primary tumor; however, the metastases generated are responsible for more than 90% of cancer deaths. Many metastatic processes initially require the total or partial start‐up of a program for the transformation of tumor epithelial cells into mesenchymal cells (EMT). The launching of the EMT program is stimulated by cytokines and other elements produced by the diverse types of cells composing the tumor stroma. In parallel, a process of destabilization of the extracellular matrix (ECM) takes place by means of the synthesis of proteases of the matrix metalloproteinases (MMPs) family. EMC degradation allows the exportation of some tumor cells as mesenchymal cells to the circulatory system and their subsequent implantation in a tissue distant from the primary tumor. The blocking of these both processes appears as a hypothetical stop point in the metastatic mechanism. The present review deals with the different options to achieve the inhibition of MMPs, focusing on MMP7 as a target given its involvement in the metastatic processes of a wide variety of tumors.

The simultaneous implantation of the epithelial–mesenchymal program and the synthesis and activation of matrix metalloproteinases during the first phases of the metastasis process is known. The inhibition of proteases could constitute a possible blockage of the process. The review describes the evolution of the different inhibition mechanisms that could inform applicable therapeutic mechanisms for the paralysis of the metastatic process.

Role of non-coding RNAs in response of breast cancer to radiation therapy

Breast cancer ranks as the first common cancer with a high incidence rate and mortality among women. Radiation therapy is the main therapeutic method for breast cancer patients. However, radiation resistance of tumor cells can reduce the efficacy of treatment and lead to recurrence and mortality in patients. Non-coding RNA (ncRNAs) refers to a group of small RNA molecules that are not translated into protein, while they have the ability to modulate the translation of target mRNA. Several studies have reported the altered expression of ncRNAs in response to radiation in breast cancer. NcRNAs have been found to influence on radiation response of breast cancer by regulating various mechanisms, including DNA damage response, cell cycle regulation, cell death, inflammatory response, cancer stem cell and EGFR related pathways. This paper aimed to provide a summary of current findings on ncRNAs dysregulation after irradiation. We also present the function and mechanism of ncRNAs in modulating radiosensitivity or radioresistance of breast cancer cells.

Targeting CD82/KAI1 for Precision Therapeutics in Surmounting Metastatic Potential in Breast Cancer

Metastasis is the main cause of mortality in breast cancer patients. There is an unmet need to develop therapies that can impede metastatic spread. Precision oncology has shown great promise for the treatment of cancers, as the therapeutic approach is tailored to a specific group of patients who are likely to benefit from the treatment, rather than the traditional approach of "one size fits all". CD82, also known as KAI1, a glycoprotein belonging to the tetraspanin family and an established metastasis suppressor, could potentially be exploited to hinder metastases in breast cancer. This review explores the prospect of targeting CD82 as an innovative therapeutic approach in precision medicine for breast cancer patients, with the goal of preventing cancer progression and metastasis. Such an approach would entail the selection of a subset of breast cancer patients with low levels of CD82, and instituting an appropriate treatment scheme tailored towards restoring the levels of CD82 in this group of patients. Proposed precision treatment regimens include current modalities of treating breast cancer, in combination with either clinically approved drugs that could restore the levels of CD82, CD82 peptide mimics or non-coding RNA-based therapeutics.

Exosomes of Mesenchymal Stem Cells as a Proper Vehicle for Transfecting miR-145 into the Breast Cancer Cell Line and Its Effect on Metastasis

BACKGROUND

Despite recent advances in scientific knowledge and clinical practice, management, and treatment of breast cancer, as one of the leading causes of female mortality, breast cancer remains a major burden. Recently, methods employing stem cells and their derivatives, i.e., exosomes, in gene-based therapies hold great promise. Since these natural nanovesicles are able to transmit crucial cellular information which can be engineered to have robust delivery and targeting capacity, they are considered one of the modes of intercellular communication. miR-145, one of the downregulated microRNAs (miRNAs) in various cancers, can regulate tumor cell invasion, metastasis, apoptosis, and proliferation and stem cell differentiation.

OBJECTIVES

The aim of this study was to investigate the role of exosomes secreted from adipose tissue-derived mesenchymal stem cells (MSCs) for miR-145 transfection into breast cancer cells in order to weaken their expansion and metastasis.

METHODS

Here, we exploited the exosomes from adipose tissue-derived mesenchymal stem cells (MSC-Exo) to deliver miR-145 in the T-47D breast cancer cell line. Lentiviral vectors of miR-145-pLenti-III-enhanced green fluorescent protein (eGFP) and empty pLenti-III-eGFP as the backbone were used to transfect MSCs and T-47D cells. In order to find the efficiency of exosomes as a delivery vehicle, the expression level of some miR-145 target genes, including Rho-Associated Coiled-Coil Containing Protein Kinase 1 (ROCK1), Erb-B2 Receptor Tyrosine Kinase 2 (ERBB2), Matrix Metalloproteinase 9 (MMP9), and Tumor Protein p53 (TP53), was compared in all treatment groups (T-47D cells treated by miR-145-transfected MSCs and their derivatives or their backbone) and control group (untransfected T-47D cells) using real-time PCR.

RESULTS

The obtained data represented the inhibitory effect of miR-145 on apoptosis induction and metastasis in both direct miR-treated groups. However, exosome-mediated delivery caused an improved anticancer property of miR-145.

CONCLUSION

Restoration of miR-145 using MSC-Exo can be considered a potential novel therapeutic strategy in breast cancer in the future.

Plasma miR-6089 as potential diagnostic biomarker for retinoblastoma

OBJECTIVE

The purpose of this study was to screen target miRNA related to RB and explore the expression levels of target miRNA in RB and its potential value of diagnosis.

METHODS

The Affymetrix GeneChip miRNA 4.0 Array was used to screen the differential miRNAs in the plasma of 5 RB patients before and after intravenous chemotherapy, and the most significant down-regulated miRNA was selected for target miRNA. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) is used to verify the expression levels of plasma target miRNA in 30 RB patients. Then, qRT-PCR was performed to further verify the expression of target miRNA in plasma of RB patients and RB tumor tissues. Finally, receiver-operating-characteristic (ROC) curve and the area under the ROC curve (AUC) were used to evaluate the diagnostic power of plasma target miRNA.

RESULTS

The miRNA Array obtain 8 core miRNAs, 1 up-regulated and 7 down-regulated, of which miR-6089 was the most significantly down-regulated. Plasma miR-6089 levels were significantly up-regulated in RB patients. Besides, in RB tumor tissues, miR-6089 levels were also obviously up-regulated. After intravenous chemotherapy, the expression of plasma miR-6089 was significantly decreased. Furthermore, ROC curve analysis showed that miR-6089 in the plasma had a good sensitivity and specificity for distinguishing RB from the healthy control group.

CONCLUSIONS

MiR-6089 may be considered as a novel potential diagnostic biomarker for RB.

TRIAL REGISTRATION NUMBER

ChiCTR2000040154; date of registration: 2020/11/22; retrospectively registered.