miR-495 is upregulated by E12/E47 in breast cancer stem cells, and promotes oncogenesis and hypoxia resistance via downregulation of E-cadherin and REDD1

Romidepsin exhibits anti-esophageal squamous cell carcinoma activity through the DDIT4-mTORC1 pathway

Esophageal squamous cell carcinoma (ESCC) is one of the most common human malignancies worldwide and is associated with high morbidity and mortality. Current treatment options are limited, highlighting the need for development of novel effective agents. Here, a high-throughput drug screening (HTS) was performed using ESCC cell lines in both two- and three-dimensional culture systems to screen compounds that have anti-ESCC activity. Our screen identified romidepsin, a histone deactylase inhibitor, as a potential anti-ESCC agent. Romidepsin treatment decreased cell viability, induced apoptosis and cell cycle arrest in ESCC cell lines, and these findings were confirmed in ESCC cell line-derived xenografted (CDX) mouse models. Mechanically, romidepsin induced transcriptional upregulation of DNA damage-inducible transcript 4 (DDIT4) gene by histone hyperacetylation at its promoter region, leading to the inhibition of mammalian target of rapamycin complex 1 (mTORC1) pathway. Furthermore, romidepsin exhibited better efficacy and safety compared to the conventional therapeutic drugs in ESCC patient-derived xenografted (PDX) mouse models. These data indicate that romidepsin may be a novel option for anti-ESCC therapy.

Circular RNA circXPO1 Promotes Multiple Myeloma Progression by Regulating miR-495-3p/DNA Damage-Induced Transcription 4 Axis

Multiple myeloma (MM) is a hematologic malignancy that results from uncontrolled plasma cell proliferation. Circular RNAs are versatile regulators that influence cancer aggression. The pathogenic mechanism of circXPO1 in MM is still unknown. In this study, the expression of circXPO1, miR-495-3p, and DNA damage-induced transcription 4 (DDIT4) was detected. Knockdown and overexpression assays were used to evaluate the effect of circXPO1 on MM. Specifically, 5-ethynyl-2'-deoxyuridine and cell counting kit-8 assay were used to investigate cell proliferation. Meanwhile, flow cytometry was adopted to detect cell apoptosis and cell cycle. Apoptosis-associated and cell cycle-related proteins were detected by Western blot. Mechanistically, biotin RNA pull-down assay and dual-luciferase assay were implemented to verify the combination among miR495-3p and circXPO1 or DDIT4. The function of circXPO1 in vivo was explored in xenograft experiments. The results showed that circXPO1 was up-regulated in both MM samples and MM cell lines and miR-495-3p was down-regulated in MM patients. Silencing circXPO1 inhibited cell proliferation, increased apoptosis rates, and caused the G1 phase arrest. Overexpression of circXPO1 yielded opposite results. In addition, RNA pull-down experiment demonstrated the interaction between circXPO1 and miR-495-3p. Silencing miR-495-3p rescued the inhibitory function caused by the knockdown of circXPO1. DDIT4 was the target of miR-495-3p. Finally, silencing circXPO1 inhibited the growth of subcutaneous tumors in vivo. In conclusion, our findings showed that circXPO1 could promote MM progression via the miR-495-3p/DDIT4 axis.

MicroRNA-495: a therapeutic and diagnostic tumor marker

Therapeutic and diagnostic progresses have significantly reduced the mortality rate among cancer patients during the last decade. However, there is still a high rate of mortality among cancer patients. One of the important reasons involved in the high mortality rate is the late diagnosis in advanced tumor stages that causes the failure of therapeutic strategies in these patients. Therefore, investigating the molecular mechanisms involved in tumor progression has an important role in introducing the efficient early detection markers. MicroRNAs (miRNAs) as stable factors in body fluids are always considered as non-invasive diagnostic and prognostic markers. In the present review, we investigated the role of miR-495 in tumor progression. It has been reported that miR-495 has mainly a tumor suppressor function through the regulation of transcription factors and tyrosine kinases as well as cellular processes such as multidrug resistance, chromatin remodeling, and signaling pathways. This review can be an effective step towards introducing the miR-495 as a non-invasive diagnostic/prognostic marker as well as a suitable target in tumor therapy.

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

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

MiRNA-related metastasis in oral cancer: moving and shaking

Across the world, oral cancer is a prevalent tumor. Over the years, both its mortality and incidence have grown. Oral cancer metastasis is a complex process involving cell invasion, migration, proliferation, and egress from cancer tissue either by lymphatic vessels or blood vessels. MicroRNAs (miRNAs) are essential short non-coding RNAs, which can act either as tumor suppressors or as oncogenes to control cancer development. Cancer metastasis is a multi-step process, in which miRNAs can inhibit or stimulate metastasis at all stages, including epithelial-mesenchymal transition, migration, invasion, and colonization, by targeting critical genes in these pathways. On the other hand, long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), two different types of non-coding RNAs, can regulate cancer metastasis by affecting gene expression through cross-talk with miRNAs. We reviewed the scientific literature (Google Scholar, Scopus, and PubMed) for the period 2000-2023 to find reports concerning miRNAs and lncRNA/circRNA-miRNA-mRNA networks, which control the spread of oral cancer cells by affecting invasion, migration, and metastasis. According to these reports, miRNAs are involved in the regulation of metastasis pathways either by directly or indirectly targeting genes associated with metastasis. Moreover, circRNAs and lncRNAs can induce or suppress oral cancer metastasis by acting as competing endogenous RNAs to inhibit the effect of miRNA suppression on specific mRNAs. Overall, non-coding RNAs (especially miRNAs) could help to create innovative therapeutic methods for the control of oral cancer metastases.

Exportin XPO7 acts as an oncogenic factor in prostate cancer via upregulation of TCF3

PURPOSE

As a nuclear transport protein, XPO7 has been observed to show abnormal expression in various types of human cancers. However, the role of XPO7 in PCa remains elusive.

METHODS

Here, in this study, immunohistochemistry and bioinformatics were used to determine the expression pattern and prognostic significance of XPO7. To investigate the functions of XPO7 in vitro and in vivo, we knocked down XPO7 in PCa cell lines and established xenograft mice models. Then, we used multiple experiments to determine the cell proliferation, migration, invasion, cell cycle and EMT in PCa cells after XPO7 modulation. Mechanistically, we conducted RNA-seq and identified the regulating effect of XPO7 on cell cycle-related and PI3K-AKT pathways. Furthermore, we assessed the regulating correlation between XPO7 and TCF3 and verified by a series of rescue experiments.

RESULTS

We found a higher XPO7 expression in prostate cancer tissues and predicted a poorer prognosis of prostate cancer. Then, we further revealed that the ectopic expression of XPO7 in PCa cells facilitated cells proliferation, migration, cell cycle progression and EMT in vitro and promoted tumor growth in vivo. Mechanistically, we conducted RNA-seq and identified the regulating effect of XPO7 on cell cycle-related and PI3K-AKT pathways. Furthermore, a significantly positive correlation was discovered between the expression of XPO7 and TCF3. In addition, XPO7 may regulate PCa through mediating TCF3 expression. TCF3 depletion could alleviate the influence of XPO7 overexpression on malignant phenotypes of PCa cells.

CONCLUSIONS

These findings indicate that XPO7 promotes PCa initiation and progression and that targeting XPO7 might be therapeutically beneficial to patients with PCa.

Hypoxia-driven ncRNAs in breast cancer

Low oxygen tension, or hypoxia is the driving force behind tumor aggressiveness, leading to therapy resistance, metastasis, and stemness in solid cancers including breast cancer, which now stands as the leading cause of cancer-related mortality in women. With the great advancements in exploring the regulatory roles of the non-coding genome in recent years, the wide spectrum of hypoxia-responsive genome is not limited to just protein-coding genes but also includes multiple types of non-coding RNAs, such as micro RNAs, long non-coding RNAs, and circular RNAs. Over the years, these hypoxia-responsive non-coding molecules have been greatly implicated in breast cancer. Hypoxia drives the expression of these non-coding RNAs as upstream modulators and downstream effectors of hypoxia inducible factor signaling in the favor of breast cancer through a myriad of molecular mechanisms. These non-coding RNAs then contribute in orchestrating aggressive hypoxic tumor environment and regulate cancer associated cellular processes such as proliferation, evasion of apoptotic death, extracellular matrix remodeling, angiogenesis, migration, invasion, epithelial-to-mesenchymal transition, metastasis, therapy resistance, stemness, and evasion of the immune system in breast cancer. In addition, the interplay between hypoxia-driven non-coding RNAs as well as feedback and feedforward loops between these ncRNAs and HIFs further contribute to breast cancer progression. Although the current clinical implications of hypoxia-driven non-coding RNAs are limited to prognostics and diagnostics in breast cancer, extensive explorations have established some of these hypoxia-driven non-coding RNAs as promising targets to treat aggressive breast cancers, and future scientific endeavors hold great promise in targeting hypoxia-driven ncRNAs at clinics to treat breast cancer and limit global cancer burden.

Artificial intelligence-driven pan-cancer analysis reveals miRNA signatures for cancer stage prediction

The ability to detect cancer at an early stage in patients who would benefit from effective therapy is a key factor in increasing survivability. This work proposes an evolutionary supervised learning method called CancerSig to identify cancer stage-specific microRNA (miRNA) signatures for early cancer predictions. CancerSig established a compact panel of miRNA signatures as potential markers from 4,667 patients with 15 different types of cancers for the cancer stage prediction, and achieved a mean performance: 10-fold cross-validation accuracy, sensitivity, specificity, and area under the receiver operating characteristic curve of 84.27% ± 6.31%, 0.81 ± 0.12, 0.80 ± 0.10, and 0.80 ± 0.06, respectively. The pan-cancer analysis of miRNA signatures suggested that three miRNAs, hsa-let-7i-3p, hsa-miR-362-3p, and hsa-miR-3651, contributed significantly toward stage prediction across 8 cancers, and each of the 67 miRNAs of the panel was a biomarker of stage prediction in more than one cancer. CancerSig may serve as the basis for cancer screening and therapeutic selection..

Hypoxia: syndicating triple negative breast cancer against various therapeutic regimens

Triple-negative breast cancer (TNBC) is one of the deadliest subtypes of breast cancer (BC) for its high aggressiveness, heterogeneity, and hypoxic nature. Based on biological and clinical observations the TNBC related mortality is very high worldwide. Emerging studies have clearly demonstrated that hypoxia regulates the critical metabolic, developmental, and survival pathways in TNBC, which include glycolysis and angiogenesis. Alterations to these pathways accelerate the cancer stem cells (CSCs) enrichment and immune escape, which further lead to tumor invasion, migration, and metastasis. Beside this, hypoxia also manipulates the epigenetic plasticity and DNA damage response (DDR) to syndicate TNBC survival and its progression. Hypoxia fundamentally creates the low oxygen condition responsible for the alteration in Hypoxia-Inducible Factor-1alpha (HIF-1α) signaling within the tumor microenvironment, allowing tumors to survive and making them resistant to various therapies. Therefore, there is an urgent need for society to establish target-based therapies that overcome the resistance and limitations of the current treatment plan for TNBC. In this review article, we have thoroughly discussed the plausible significance of HIF-1α as a target in various therapeutic regimens such as chemotherapy, radiotherapy, immunotherapy, anti-angiogenic therapy, adjuvant therapy photodynamic therapy, adoptive cell therapy, combination therapies, antibody drug conjugates and cancer vaccines. Further, we also reviewed here the intrinsic mechanism and existing issues in targeting HIF-1α while improvising the current therapeutic strategies. This review highlights and discusses the future perspectives and the major alternatives to overcome TNBC resistance by targeting hypoxia-induced signaling.

The Intricate Interplay between Cancer Stem Cells and Oncogenic miRNAs in Breast Cancer Progression and Metastasis

Complex signaling interactions between cancer cells and their microenvironments drive the clonal selection of cancer cells. Opposing forces of antitumor and tumorigenic potential regulate the survival of the fittest clones, while key genetic and epigenetic alterations in healthy cells force them to transform, overcome cell senescence, and proliferate in an uncontrolled manner. Both clinical samples and cancer cell lines provide researchers with an insight into the complex structure and hierarchy of cancer. Intratumor heterogeneity allows for multiple cancer cell subpopulations to simultaneously coexist within tumors. One category of these cancer cell subpopulations is cancer stem cells (CSCs), which possess stem-like characteristics and are not easily detectable. In the case of breast cancer, which is the most prevalent cancer type among females, such subpopulations of cells have been isolated and characterized via specific stem cell markers. These stem-like cells, known as breast cancer stem cells (BCSCs), have been linked to major events during tumorigenesis including invasion, metastasis and patient relapse following conventional therapies. Complex signaling circuitries seem to regulate the stemness and phenotypic plasticity of BCSCs along with their differentiation, evasion of immunosurveillance, invasiveness and metastatic potential. Within these complex circuitries, new key players begin to arise, with one of them being a category of small non-coding RNAs, known as miRNAs. Here, we review the importance of oncogenic miRNAs in the regulation of CSCs during breast cancer formation, promotion and metastasis, in order to highlight their anticipated usage as diagnostic and prognostic tools in the context of patient stratification and precision medicine.

miR-495-3p sensitizes BCR-ABL1-expressing leukemic cells to tyrosine kinase inhibitors by targeting multidrug resistance 1 gene in T315I mutated cells

Chronic myeloid leukemia (CML) is a clonal hematopoietic malignancy driven by the BCR-ABL1 fusion oncoprotein. The development of tyrosine kinase inhibitors (TKIs) has deeply increased long-term survival of CML patients. Nonetheless, one patient out of four will switch TKI off owing either to drug intolerance or resistance partly due to amplification or mutations of BCR-ABL1 oncogene and alteration in ATP-binding cassette (ABC) transporters. Increasing evidence suggests the involvement of the microRNA miR-495-3p in cancer-associated chemoresistance through multidrug resistance 1 (MDR1) gene, which encodes an ATP-dependent efflux pump. Our study aimed at investigating the potential role of miR-495-3p in CML TKI chemo-sensitivity and determining the underlying molecular circuitry involved. We first observed that miR-495-3p expression was lower in BCR-ABL1-expressing cellular models in vitro. Notably, loss-of-function experiments showed increased proliferation associated with a decreased number of nondividing cells (G0/G1) and resistance to Imatinib. Conversely, our data showed that miR-495-3p overexpression hindered leukemic cell growth and TKI resistance in Imatinib-resistant T315I-mutant cells, as well as drug efflux activity through MDR1 regulation. Further investigating the role of miR-495-3p in CML patients, we found that predicted miR-495-3p targets were upregulated in patients in blast crisis that were involved in protein phosphorylation and associated with the worst prognosis. Taken together, our results demonstrate that downregulation of miR-495-3p expression is important in the malignant phenotype of CML and TKI resistance mechanisms and could be a useful biomarker and a potential therapeutic target to eradicate CML.

FBXL2 promotes E47 protein instability to inhibit breast cancer stemness and paclitaxel resistance

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer with a high risk of metastasis and recurrence. Although chemotherapy has greatly improved the clinical outcome of TNBC patients, acquired drug resistance remains a huge challenge for TNBC treatment. Breast cancer stem cells (BCSCs) play a critical role in breast cancer development, metastasis, recurrence, and chemotherapy resistance. Thus, it is of great importance to decipher the underlying molecular mechanism of BCSCs regulation for TNBC drug resistance. In this study, we demonstrate that the F-box protein FBXL2 is a critical negative regulator of BCSCs stemness and that downregulation of FBXL2 plays a causal role in TNBC drug resistance. We show that expression levels of FBXL2 significantly influence CD44^high/CD24^low subpopulation and the mammosphere formation ability of TNBC cells. Ectopic expression of FBXL2 inhibits initiation of TNBC and overcomes paclitaxel resistance in vivo. In addition, activation of FBXL2 by nebivolol, a clinically used small-molecule inhibitor of the beta-1 receptor, markedly overcomes BCSCs-induced paclitaxel resistance. Mechanistically, we show that FBXL2 targets transcriptional factor E47 for polyubiquitin- and proteasome-mediated degradation, resulting in inhibition of BCSC stemness. Clinical analyses indicate that low expression of FBXL2 correlates with high expression of E47 as well as with high stemness features, and is associated with poor clinical outcomes of breast cancer patients. Taken together, these results highlight that the FBXL2-E47 axis plays a critical role in the regulation of BCSC stemness and paclitaxel resistance. Thus, targeting FBXL2 might be a potential therapeutic strategy for drug-resistant TNBC.

RNA interference: Promising approach for breast cancer diagnosis and treatment

Today, cancer is one of the main health-related challenges, and in the meantime, breast cancer (BC) is one of the most common cancers among women, with an alarming number of incidences and deaths every year. For this reason, the discovery of novel and more effective approaches for the diagnosis, treatment, and monitoring of the disease are very important. In this regard, scientists are looking for diagnostic molecules to achieve the above-mentioned goals with higher accuracy and specificity. RNA interference (RNAi) is a posttranslational regulatory process mediated by microRNA intervention and small interfering RNAs. After transcription and edition, these two noncoding RNAs are integrated and activated with the RNA-induced silencing complex (RISC) and AGO2 to connect the target mRNA by their complementary sequence and suppress their translation, thus reducing the expression of their target genes. These two RNAi categories show different patterns in different BC types and stages compared to healthy cells, and hence, these molecules have high diagnostic, monitoring, and therapeutic potentials. This article aims to review the RNAi pathway and diagnostic and therapeutic potentials with a special focus on BC.

Non-coding RNAs and epithelial mesenchymal transition in cancer: molecular mechanisms and clinical implications

Epithelial-mesenchymal transition (EMT) is a fundamental process for embryonic development during which epithelial cells acquire mesenchymal characteristics, and the underlying mechanisms confer malignant features to carcinoma cells such as dissemination throughout the organism and resistance to anticancer treatments. During the past decades, an entire class of molecules, called non-coding RNA (ncRNA), has been characterized as a key regulator of almost every cellular process, including EMT. Like protein-coding genes, ncRNAs can be deregulated in cancer, acting as oncogenes or tumor suppressors. The various forms of ncRNAs, including microRNAs, PIWI-interacting RNAs, small nucleolar RNAs, transfer RNA-derived RNA fragments, long non-coding RNAs, and circular RNAs can orchestrate the complex regulatory networks of EMT at multiple levels. Understanding the molecular mechanism underlying ncRNAs in EMT can provide fundamental insights into cancer metastasis and may lead to novel therapeutic approaches. In this review, we describe recent advances in the understanding of ncRNAs in EMT and provide an overview of recent ncRNA applications in the clinic.

A novel role of PRL in regulating epithelial cell density by inducing apoptosis at confluence

Maintaining proper epithelial cell density is essential for the survival of multicellular organisms. While regulation of cell density through apoptosis is well known, its mechanistic details remain elusive. Here, we report the involvement of membrane-anchored phosphatase of regenerating liver (PRL), originally known for its role in cancer malignancy, in this process. In epithelial MDCK cells, upon confluence, doxycycline-induced expression of PRL upregulated apoptosis, reducing the cell density. This could be circumvented by artificially reducing the cell density via stretching the cell-seeded silicon chamber. Moreover, siRNA-mediated knockdown of endogenous PRL blocked apoptosis, leading to greater cell density. Mechanistically, PRL promoted apoptosis by upregulating the translation of E-cadherin and activating TGF-β pathway. Morpholino-mediated inhibition of PRL expression in zebrafish embryos caused developmental defect with reduced apoptosis and increased epithelial cell density during convergent extension. This study revealed a novel role of PRL in regulating density-dependent apoptosis in vertebrate epithelium.

Adhesion of monocytes and endothelial cells isolated from the human aorta suppresses by miRNA-PEI particles

Background

Knowledge of stenosis in coronary arteries requires an understanding of the cellular and molecular processes that occur throughout the leukocyte rolling process. In this study, the roles of miR-125a-5p and miR-495-3p were investigated on the adhesion of endothelial cells (ECs) isolated from the human aorta.

Methods

Human primary endothelial cells were obtained from the aorta of people who had died of brain death. Whole blood was used to isolate the monocytes. The miR-125 and miR-495 were predicted and transfected into ECs using Poly Ethylene Imine (PEI). The expression levels of adhesion molecules and monocyte recruitment were identified by the RT-qPCR technique and Leukocyte-Endothelial Adhesion Assay kit, respectively.

Results

The ICAM-1, ICAM-2 and VCAM-1 expression levels decreased significantly in the miR-495/PEI-transfected ECs (P < 0.05) while in the miR-125/PEI-transfected ECs only the ICAM-2 and ITGB-2 expression levels decreased significantly (P < 0.05) as compared to the miR-synthetic/PEI-transfected ECs. Furthermore, the monocyte adhesion was decreased in the miR-125 and miR-mix/PEI-transfected ECs as compared to the miR-synthetic/PEI-transfected ECs (P = 0.01 and P = 0.04, respectively).

Conclusion

According to the findings, the efficient relations between miR-125 and adhesion molecules may be responsible for the inhibition of monocyte rolling.

Emerging Evidence of the Functional Impact of the miR379/miR656 Cluster (C14MC) in Breast Cancer

Many microRNAs exist in clusters that share comparable sequence homology and may target genes in a common pathway. The miR-379/miR-656 (C14MC) cluster is imprinted in the DLK1-Dio3 region of 14q32.3 and contains 42 miRNAs. It plays a functional role in numerous biological pathways including vascular remodeling and early development. With many C14MC miRNAs highlighted as potential tumor suppressors in a variety of cancers, the role of this cluster in breast cancer (BC) has garnered increased attention in recent years. This review focuses on C14MC in BC, providing an overview of the constituent miRNAs and addressing each in terms of functional impact, potential target genes/pathways, and, where relevant, biomarker capacity. Studies have revealed the regulation of key factors in disease progression and metastasis including tyrosine kinase pathways and factors critical to epithelial–mesenchymal transition (EMT). This has potentially important clinical implications, with EMT playing a critical role in BC metastasis and tyrosine kinase inhibitors (TKIs) in widespread use for the treatment of BC. While the majority of studies have reported tumor-suppressing roles for these miRNAs, some have highlighted their potential as oncomiRs. Understanding the collective contribution of miRNAs within C14MC to BC may support improved understanding of disease etiology and present novel approaches to targeted therapy.

Downregulation of MicroRNA-495 Alleviates IL-1β Responses among Chondrocytes by Preventing SOX9 Reduction

PURPOSE

Our previous work demonstrated that miRNA-495 targets SOX9 to inhibit chondrogenesis of mesenchymal stem cells. In this study, we aimed to investigate whether miRNA-495-mediated SOX9 regulation could be a novel therapeutic target for osteoarthritis (OA) using an in vitro cell culture model.

MATERIALS AND METHODS

An in vitro model mimicking the OA environment was established using TC28a2 normal human chondrocyte cells. Interleukin-1β (IL-1β, 10 ng/mL) was utilized to induce inflammation-related changes in TC28a2 cells. Safranin O staining and glycosaminoglycan assay were used to detect changes in proteoglycans among TC28a2 cells. Expression levels of COX-2, ADAMTS5, MMP13, SOX9, CCL4, and COL2A1 were examined by qRT-PCR and/or Western blotting. Immunohistochemistry was performed to detect SOX9 and CCL4 proteins in human cartilage tissues obtained from patients with OA.

RESULTS

miRNA-495 was upregulated in IL-1β-treated TC28a2 cells and chondrocytes from damaged cartilage tissues of patients with OA. Anti-miR-495 abolished the effect of IL-1β in TC28a2 cells and rescued the protein levels of SOX9 and COL2A1, which were reduced by IL-1β. SOX9 was downregulated in the damaged cartilage tissues of patients with OA, and knockdown of SOX9 abolished the effect of anti-miR-495 on IL-1β-treated TC28a2 cells.

CONCLUSION

We demonstrated that inhibition of miRNA-495 alleviates IL-1β-induced inflammatory responses in chondrocytes by rescuing SOX9 expression. Accordingly, miRNA-495 could be a potential novel target for OA therapy, and the application of anti-miR-495 to chondrocytes could be a therapeutic strategy for treating OA.

Delivery of LNA-antimiR-142-3p by Mesenchymal Stem Cells-Derived Exosomes to Breast Cancer Stem Cells Reduces Tumorigenicity

Exosomes, nano-sized cell-derived vesicles, have been employed as non-synthetic carriers of various pharmaceutics in numerous studies. As higher expression levels of miR-142-3p and miR-150 in breast cancer stem cells (BCSCs) are associated with their clonogenic and tumorigenic capabilities, the present study aims to exploit the mesenchymal stem cells-derived exosomes (MSCs-Exo) to deliver LNA-antimiR-142-3p into MCF7-derived cancer stem-like cells to suppress expression levels of miR-142-3p and miR-150 in order to reduce clonogenicity and tumorigenicity. Our results indicated that the MSCs-Exo can efficiently deliver the LNA-antimiR-142-3p to breast cancer stem-like cells to reduce the miR-142-3p and miR-150 expression levels. Furthermore, the inhibition of the oncomiRs with the delivery of LNA-antimiR-142-3p resulted in a significant reduction of clone-formation and tumor-initiating abilities of the MCF7-derived cancer stem-like cells. In conclusion, we showed that MSCs-derived exosomes could be used as a feasible nanovehicles to deliver RNA-based therapeutics into BCSCs to improve the cancer treatment. HIGHLIGHTS: Exosomes secreted by bone marrow-derived mesenchymal stem cells efficiently transfer the LNA-antimiR-142-3p to breast cancer stem cells. Exosomes-mediated delivery of LNA-antimiR-142-3p to the breast cancer stem cells leads to downregulation of miR-142-3p and miR-150 and the overexpression of target genes. Delivery of LNA-antimiR-142-3p by the exosomes reduces the colony formation capability of breast cancer stem cells in vitro. Inhibition of miR-142-3p and miR-150 by the LNA-antimiR-142-3p loaded exosomes reduces the tumorigenicity of breast cancer stem cells in vivo.

Anti-tumor Activity of Propofol: A Focus on MicroRNAs

BACKGROUND

MicroRNAs are endogenous, short, non-coding RNAs with the length as low as 20 to 25 nucleotides. These RNAs are able to negatively affect the gene expression at the post-transcriptional level. It has been demonstrated that microRNAs play a significant role in cell proliferation, cell migration, cell death, cell differentiation, infection, immune response, and metabolism. Besides, the dysfunction of microRNAs has been observed in a variety of cancers. So, modulation of microRNAs is of interest in the treatment of disorders.

OBJECTIVE

The aim of the current review is to investigate the modulatory effect of propofol on microRNAs in cancer therapy.

METHODS

This review was performed at PubMed, SCOPUS and Web of Science data-bases using keywords "propofol', "microRNA", "cancer therapy", "propofol + microRNA" and "propofol + miR".

RESULTS

It was found that propofol dually down-regulates/upregulates microRNAs to exert its antitumor activity. In terms of oncogenesis microRNAs, propofol exert an inhibitory effect, while propofol significantly enhances the expression of oncosuppressor microRNAs.

CONCLUSION

It seems that propofol is a potential modulator of microRNAs and this capability can be used in the treatment of various cancers.

DDIT4 Novel Mutations in Pancreatic Cancer

Pancreatic cancer is one of the most common malignancies worldwide. This study is aimed at searching the possible genetic mutations and the value of novel gene mutation in the DNA damage-inducible transcript 4 (DDIT4) and signaling pathway in pancreatic cancer. Polymerase chain reaction (PCR) was performed to amplify the DNA sequences of DDIT4 from patients with pancreatic ductal adenocarcinoma. In addition, we used IHC to detect the expression level of DDIT4 in patients with pancreatic cancer in different types of gene mutation. Double-labeled immunofluorescence was employed to explore the expression levels of DDIT4/LC3 and their potential correlation. Our work indicated the two novel stable gene mutations in DDIT4 mRNA 3'-untranslated region (m.990 U>A and m.1246 C>U). Thirteen samples were found to have mutation in the DDIT4 3'-untranslated regions (UTR). To further verify the influence of gene mutation on protein expression, we performed immunohistochemistry on different gene mutation types, and we found a correlation between DDIT4 expression and gene mutation, which is accompanied by nuclear staining deepening. In order to further discuss the clinical value of DDIT4 gene mutation, immunofluorescence suggested that the expression of DDIT4 colocated with LC3; thus, we speculated that DDIT4 mutation may be involved in autophagy in pancreatic cancer cell. In this study, we found mutation in the 3'-UTR region of DDIT4, which may be associated with DDIT4 expression and tumor autophagy in pancreatic cancer tissues.

The Anticancer Effects of Flavonoids through miRNAs Modulations in Triple-Negative Breast Cancer

Triple- negative breast cancer (TNBC) incidence rate has regularly risen over the last decades and is expected to increase in the future. Finding novel treatment options with minimum or no toxicity is of great importance in treating or preventing TNBC. Flavonoids are new attractive molecules that might fulfill this promising therapeutic option. Flavonoids have shown many biological activities, including antioxidant, anti-inflammatory, and anticancer effects. In addition to their anticancer effects by arresting the cell cycle, inducing apoptosis, and suppressing cancer cell proliferation, flavonoids can modulate non-coding microRNAs (miRNAs) function. Several preclinical and epidemiological studies indicate the possible therapeutic potential of these compounds. Flavonoids display a unique ability to change miRNAs' levels via different mechanisms, either by suppressing oncogenic miRNAs or activating oncosuppressor miRNAs or affecting transcriptional, epigenetic miRNA processing in TNBC. Flavonoids are not only involved in the regulation of miRNA-mediated cancer initiation, growth, proliferation, differentiation, invasion, metastasis, and epithelial-to-mesenchymal transition (EMT), but also control miRNAs-mediated biological processes that significantly impact TNBC, such as cell cycle, immune system, mitochondrial dysregulation, modulating signaling pathways, inflammation, and angiogenesis. In this review, we highlighted the role of miRNAs in TNBC cancer progression and the effect of flavonoids on miRNA regulation, emphasizing their anticipated role in the prevention and treatment of TNBC.

MiR-495 regulates cell proliferation and apoptosis in H2O2 stimulated rat spinal cord neurons through targeting signal transducer and activator of transcription 3 (STAT3)

Background

MicroRNA-495 (miR-495) is a post-translational modulator that performs several functions, and it is involved in several disease states. On the other hand, the physiological functions of miR-495 in H₂O₂ stimulated mouse spinal cord neuronal dysfunction have not yet been fully understood.

Methods

In this study, we speculated that miR-495 may regulate the expression of STAT3 in the processes of neuronal proliferation and apoptosis following spinal cord injury (SCI). Cell viability was assessed with methyl thiazolyl tetrazolium (MTT) assay. Caspase-3 activity was assayed with ELISA. Cellular apoptotic changes were measured with TUNEL assay. Intracellular ROS production was determined by measuring uptake of dichlorodihydrofluorescein diacetate (DCFH-DA; PCR was used to assay the mRNA expression of STAT3 gene bearing predicted targeting positions for miR-495, while qRT-PCR was used to measure miR-495 mRNA.

Results

The results demonstrated that treatment of SCNs with H₂O₂ led to a significant decrease in cell survival, while it enhanced apoptosis. The H₂O₂ treatment induced cell membrane dysfunction, and increased ROS levels and DNA damage. Interestingly, the expression of miR-495 was markedly suppressed when SCNs were exposed to H₂O₂. However, miR-495 overexpression reversed H₂O₂-induced cytotoxicity and apoptosis in SCNs. Moreover, H₂O₂ exposure elevated protein and mRNA concentrations of STAT3 in SCNs. Bioinformatics analysis showed likely binding domains of miR-495 in the 3'-untranslated regions of STAT3 in SCNs. MiR-495 loss-of-function and gain-of-function significantly up-regulated and down-regulated both STAT3 mRNA and protein expressions, respectively, in SCNs.

Conclusions

miR-495 overexpression inhibited H₂O₂-induced SCN dysfunction. This mechanism was mediated through the down-regulation of STAT3 expression.

Flavonoid display ability to target microRNAs in cancer pathogenesis

MicroRNAs (miRNAs) are non-coding, conserved, single-stranded nucleotide sequences involved in physiological and developmental processes. Recent evidence suggests an association between miRNAs' deregulation with initiation, promotion, progression, and drug resistance in cancer cells. Besides, miRNAs are known to regulate the epithelial-mesenchymal transition, angiogenesis, autophagy, and senescence in different cancer types. Previous reports proposed that apart from the antioxidant potential, flavonoids play an essential role in miRNAs modulation associated with changes in cancer-related proteins, tumor suppressor genes, and oncogenes. Thus, flavonoids can suppress proliferation, help in the development of drug sensitivity, suppress metastasis and angiogenesis by modulating miRNAs expression. In the present review, we summarize the role of miRNAs in cancer, drug resistance, and the chemopreventive potential of flavonoids mediated by miRNAs. The potential of flavonoids to modulate miRNAs expression in different cancer types demonstrate their selectivity and importance as regulators of carcinogenesis. Flavonoids as chemopreventive agents targeting miRNAs are extensively studied in vitro, in vivo, and pre-clinical studies, but their efficiency in targeting miRNAs in clinical studies is less investigated. The evidence presented in this review highlights the potential of flavonoids in cancer prevention/treatment by regulating miRNAs, although further investigations are required to validate and establish their clinical usefulness.

DDIT4 Licenses Only Healthy Cells to Proliferate During Injury-induced Metaplasia

BACKGROUND AND AIMS

In stomach, metaplasia can arise from differentiated chief cells that become mitotic via paligenosis, a stepwise program. In paligenosis, mitosis initiation requires reactivation of the cellular energy hub mTORC1 after initial mTORC1 suppression by DNA damage induced transcript 4 (DDIT4 aka REDD1). Here, we use DDIT4-deficient mice and human cells to study how metaplasia increases tumorigenesis risk.

METHODS

A tissue microarray of human gastric tissue specimens was analyzed by immunohistochemistry for DDIT4. C57BL/6 mice were administered combinations of intraperitoneal injections of high-dose tamoxifen (TAM) to induce spasmolytic polypeptide-expressing metaplasia (SPEM) and rapamycin to block mTORC1 activity, and N-methyl-N-nitrosourea (MNU) in drinking water to induce spontaneous gastric tumors. Stomachs were analyzed for proliferation, DNA damage, and tumor formation. CRISPR/Cas9-generated DDIT4-/- and control human gastric cells were analyzed for growth in vitro and in xenografts with and without 5-fluorouracil (5-FU) treatment.

RESULTS

DDIT4 was expressed in normal gastric chief cells in mice and humans and decreased as chief cells became metaplastic. Paligenotic Ddit4-/- chief cells maintained constitutively high mTORC1, causing increased mitosis of metaplastic cells despite DNA damage. Lower DDIT4 expression correlated with longer survival of patients with gastric cancer. 5-FU-treated DDIT4-/- human gastric epithelial cells had significantly increased cells entering mitosis despite DNA damage and increased proliferation in vitro and in xenografts. MNU-treated Ddit4-/- mice had increased spontaneous tumorigenesis after multiple rounds of paligenosis induced by TAM.

CONCLUSIONS

During injury-induced metaplastic proliferation, failure of licensing mTORC1 reactivation correlates with increased proliferation of cells harboring DNA damage, as well as increased tumor formation and growth in mice and humans.

Long non‑coding RNA SNHG20 promotes colorectal cancer cell proliferation, migration and invasion via miR‑495/STAT3 axis

Colorectal cancer (CRC) is one of the primary causes of cancer-associated mortality worldwide. However, the potential molecular mechanism of CRC progression remains unknown. Long non-coding RNA small nucleolar RNA host gene 20 (SNHG20) has been demonstrated to be involved in the development and progression of a variety of tumors, including CRC. However, the involvement of SNHG20 in CRC progression remains unclear. The aim of the present study was to investigate the functional role and molecular mechanism of SNHG20 in CRC progression. In the present study, SNHG20 expression was found to be significantly upregulated in CRC tissues and cell lines. Association analysis indicated that high SNHG20 expression was significantly association with greater tumor size (P=0.014), tumor invasion depth (P=0.019), positive lymph node status (P=0.022), distant metastasis (P=0.017) and advanced tumor node metastasis stage (P=0.038). Loss-of-function experiments indicated that SNHG20 knockdown could significantly suppress proliferation, migration and invasion in vitro. Notably, SNHG20 knockdown significantly inhibited tumor growth and lung metastasis in vivo. Bioinformatics analysis and luciferase reporter assays confirmed that microRNA (miR)-495 was a direct target of SNHG20. Rescue assays indicated that miR-495 inhibitor reversed the suppressive effects of SNHG20 knockdown on CRC progression. Moreover, STAT3 was identified as a downstream target of miR-495 in CRC. STAT3 overexpression partially rescued the inhibitory effects of SNHG20 knockdown on CRC progression. Taken together, the results revealed that SNHG20 facilitated CRC progression by regulating STAT3 expression and by sponging miR-495.

The Role of Breast Cancer Stem Cell-Related Biomarkers as Prognostic Factors

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide, and its incidence is on the rise. A small fraction of cancer stem cells was identified within the tumour bulk, which are regarded as cancer-initiating cells, possess self-renewal and propagation potential, and a key driver for tumour heterogeneity and disease progression. Cancer heterogeneity reduces the overall efficacy of chemotherapy and contributes to treatment failure and relapse. The cell-surface and subcellular biomarkers related to breast cancer stem cell (BCSC) phenotypes are increasingly being recognised. These biomarkers are useful for the isolation of BCSCs and can serve as potential therapeutic targets and prognostic tools to monitor treatment responses. Recently, the role of noncoding microRNAs (miRNAs) has extensively been explored as novel biomarker molecules for breast cancer diagnosis and prognosis with high specificity and sensitivity. An in-depth understanding of the biological roles of miRNA in breast carcinogenesis provides insights into the pathways of cancer development and its utility for disease prognostication. This review gives an overview of stem cells, highlights the biomarkers expressed in BCSCs and describes their potential role as prognostic indicators.

Is REDD1 a metabolic double agent? Lessons from physiology and pathology

The Akt/mechanistic target of rapamycin (mTOR) signaling pathway governs macromolecule synthesis, cell growth, and metabolism in response to nutrients and growth factors. Regulated in development and DNA damage response (REDD)1 is a conserved and ubiquitous protein, which is transiently induced in response to multiple stimuli. Acting like an endogenous inhibitor of the Akt/mTOR signaling pathway, REDD1 protein has been shown to regulate cell growth, mitochondrial function, oxidative stress, and apoptosis. Recent studies also indicate that timely REDD1 expression limits Akt/mTOR-dependent synthesis processes to spare energy during metabolic stresses, avoiding energy collapse and detrimental consequences. In contrast to this beneficial role for metabolic adaptation, REDD1 chronic expression appears involved in the pathogenesis of several diseases. Indeed, REDD1 expression is found as an early biomarker in many pathologies including inflammatory diseases, cancer, neurodegenerative disorders, depression, diabetes, and obesity. Moreover, prolonged REDD1 expression is associated with cell apoptosis, excessive reactive oxygen species (ROS) production, and inflammation activation leading to tissue damage. In this review, we decipher several mechanisms that make REDD1 a likely metabolic double agent depending on its duration of expression in different physiological and pathological contexts. We also discuss the role played by REDD1 in the cross talk between the Akt/mTOR signaling pathway and the energetic metabolism.

The emerging role of miRNA clusters in breast cancer progression

Micro RNAs (miRNAs) are small non-coding RNAs that are essential for regulation of gene expression of the target genes. Large number of miRNAs are organized into defined units known as miRNA clusters (MCs). The MCs consist of two or more than two miRNA encoding genes driven by a single promoter, transcribed together in the same orientation, that are not separated from each other by a transcription unit. Aberrant miRNA clusters expression is reported in breast cancer (BC), exhibiting both pro-tumorogenic and anti-tumorigenic role. Altered MCs expression facilitates to breast carcinogenesis by promoting the breast cells to acquire the various hallmarks of the cancer. Since miRNA clusters contain multiple miRNA encoding genes, targeting cluster may be more attractive than targeting individual miRNAs. Besides targeting dysregulated miRNA clusters in BC, studies have focused on the mechanism of action, and its contribution to the progression of the BC. The present review provides a comprehensive overview of dysregulated miRNA clusters and its role in the acquisition of cancer hallmarks in BC. More specifically, we have presented the regulation, differential expression, classification, targets, mechanism of action, and signaling pathways of miRNA clusters in BC. Additionally, we have also discussed the potential utility of the miRNA cluster as a diagnostic and prognostic indicator in BC.

SARS-CoV-2 may regulate cellular responses through depletion of specific host miRNAs

Cold viruses have generally been considered fairly innocuous until the appearance of the severe acute respiratory coronavirus 2 (SARS-CoV-2) in 2019, which caused the coronavirus disease 2019 (COVID-19) global pandemic. Two previous viruses foreshadowed that a coronavirus could potentially have devastating consequences in 2002 [severe acute respiratory coronavirus (SARS-CoV)] and in 2012 [Middle East respiratory syndrome coronavirus (MERS-CoV)]. The question that arises is why these viruses are so different from the relatively harmless cold viruses. On the basis of an analysis of the current literature and using bioinformatic approaches, we examined the potential human miRNA interactions with the SARS-CoV-2's genome and compared the miRNA target sites in seven coronavirus genomes that include SARS-CoV-2, MERS-CoV, SARS-CoV, and four nonpathogenic coronaviruses. Here, we discuss the possibility that pathogenic human coronaviruses, including SARS-CoV-2, could modulate host miRNA levels by acting as miRNA sponges to facilitate viral replication and/or to avoid immune responses.

miR-495 inhibits the growth of fibroblasts in hypertrophic scars

Noncoding RNAs are known to be importantly involved in a variety physiological and pathophysiolgical processes. Their role in the pathogenesis of hypertrophic scars remains unclear, however. After preliminary screening of the microRNA (miRNA) gene expression profiles, we explored the role of miR-495 in the development of hypertrophic scar by comparing expression of miR-495 and focal adhesion kinase (FAK) between hypertrophic scar and normal skin tissue. We also used 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and annexin V-fluorescein isothiocyanate/propidium iodide assays to assess the effect of miR-495 on the proliferation and apoptosis in human hypertrophic scar fibroblasts. Western blotting and real-time polymerase chain reaction were used to evaluate expression of miR-495, FAK, and related proteins in the FAK pathway. Our findings show that miR-495 inhibits FAK and its downstream mediators in vitro and vivo, and suggest that miR-495 may be a useful therapeutic target for the treatment of hypertrophic scar.

The malignancy of liver cancer cells is increased by IL-4/ERK/AKT signaling axis activity triggered by irradiated endothelial cells

The malignant traits involved in tumor relapse, metastasis and the expansion of cancer stem-like cells are acquired via the epithelial-mesenchymal transition (EMT) process in the tumor microenvironment. In addition, the tumor microenvironment strongly supports the survival and growth of malignant tumor cells and further contributes to the reduced efficacy of anticancer therapy. Ionizing radiation can influence the tumor microenvironment, because it alters the biological functions of endothelial cells composing tumor vascular systems. However, to date, studies on the pivotal role of these endothelial cells in mediating the malignancy of cancer cells in the irradiated tumor microenvironment are rare. We previously evaluated the effects of irradiated endothelial cells on the malignant traits of human liver cancer cells and reported that endothelial cells irradiated with 2 Gy reinforce the malignant properties of these cancer cells. In this study, we investigated the signaling mechanisms underlying these events. We revealed that the increased expression level of IL-4 in endothelial cells irradiated with 2 Gy eventually led to enhanced migration and invasion of cancer cells and further expansion of cancer stem-like cells. In addition, this increased level of IL-4 activated the ERK and AKT signaling pathways to reinforce these events in cancer cells. Taken together, our data indicate that ionizing radiation may indirectly modulate malignancy by affecting endothelial cells in the tumor microenvironment. Importantly, these indirect effects on malignancy are thought to offer valuable clues or targets for overcoming the tumor recurrence after radiotherapy.

Cell-free miRNAs as non-invasive biomarkers in breast cancer: Significance in early diagnosis and metastasis prediction

Breast cancer is one of the genetic diseases causing a high mortality among women around the world. Despite the availability of advanced diagnostic tools and treatment strategies, the incidence of breast cancer is increasing every year. This is due to the lack of accurate and reliable biomarkers whose deficiency creates difficulty in early breast cancer recognition, subtypes determination, and metastasis prophecy. Although biomarkers such as ER, PR, Her2, Ki-67, and other genetic platforms e.g. MammaPrint®, Oncotype DX®, Prosigna® or EndoPredict® are available for determination of breast cancer diagnosis and prognosis. However, pertaining to heterogeneous nature, lack of sensitivity, and specificity of these markers, it is still incessant to overcome breast cancer burden. Therefore, a novel biomarker is urgently needed for therapeutic diagnosis and improving prognosis. Lately, it has become more evident that cell-free miRNAs might be useful as good non-invasive biomarkers that are associated with different events in carcinogenesis. For example, some known biomarkers such as miR-21, miR-23a, miR-34a are associated with molecular subtyping and different biomolecular aspects i.e. apoptosis, angiogenesis, metastasis, and miR-1, miR-10b, miR-16 are associated with drug response. Cell-free miRNAs present in human body fluids have proven to be potential biomarkers with significant prognostic and predictive values. Numerous studies have found a distinct expression profile of circulating miRNAs in breast tumour versus non-tumour and in early and advanced-stage, thus implicating its clinical relevance. This review article will highlight the importance of different cell-free miRNAs as a biomarker for early breast cancer detection, subtype classification, and metastasis forecast.

Combination Therapy with Vitamin C Could Eradicate Cancer Stem Cells

Cancer remains one of the most feared and dreaded diseases in this era of modern medicine, claiming the lives of many, and affecting the quality of life of several others around the globe despite major advances in the diagnosis, treatment, palliative care and the immense resources invested into cancer research. While research in cancer has largely focused on the neoplasm/tumor and the cancerous cells that make up the tumor, more recently, the existence, proliferation, differentiation, migration and invasion of cancer stem cells (CSCs) and the role that CSCs play in tumor initiation, progression, metastasis, drug resistance and relapse/recurrence of the disease has gained widespread interest in cancer research. Although the conventional therapeutic approaches such as surgery, chemotherapy and radiation therapy are effective cancer treatments, very often these treatment modalities fail to target the CSCs, which then later become the source of disease recurrence. A majority of the anti-cancer agents target rapidly dividing cancer cells and normal cells and hence, have side effects that are not expected. Targeting CSCs remains a challenge due to their deviant nature with a low proliferation rate and increased drug resistance mechanism. Ascorbic acid/Vitamin C (Vit.C), a potent antioxidant, is a cofactor for several biosynthetic and gene regulatory enzymes and a vital contributor to immune defense of the body, and was found to be deficient in patients with advanced stages of cancer. Vit.C has gained importance in the treatment of cancer due to its ability to modulate the redox status of the cell and influence epigenetic modifications and significant roles in HIF1α signaling. Studies have reported that intravenous administration of Vit.C at pharmacological doses selectively kills tumor cells and targets CSCs when administered along with chemotherapeutic drugs. In the current article, we provide an in-depth review of how Vit.C plays an important role in targeting CSCs and its possible use as an adjuvant, neoadjuvant or co-treatment in the treatment of cancers.

Non-randomness distribution of micro-RNAs on human chromosomes

Background

Micro-RNA (miRNA) is one of the non-coding RNAs that exist in human genome. miRNAs play an important role in the expression of target genes. Several studies have indicated that organization of human genome is not random. In order to investigate the distribution of miRNAs on human chromosomes, the present study was carried out.

Results

Using the data from miRBase database, we found 1913 loci coding for miRNAs (MIRs). Human chromosome bands 1p36, 1q22, 1q24, 2q13, 2q35, 3p21, 6p21, 7q22, 8p23, 8q24, 9q22, 9q34, 11q12-q13, 12q13, 14q32, 16p13, 16q24, 17p13, 17q11, 17q21, 17q25, 19p13, 19q13, 20q13, 21p11, 22q13, and Xq26-q28 were significantly bearing higher number of MIRs. The 14q32 and 19q13 with 4.11 and 3.59 MIRs per mega-base pair, respectively, were the most MIR-richest human chromosomal bands. The number of MIRs on chromosomal bands significantly decreased as a function of distance from telomere (r = − 0.949, df = 5, P = 0.001).

Conclusions

Our current data suggest that MIRs are not randomly distributed on human genomes.

MicroRNAs Involved in Carcinogenesis, Prognosis, Therapeutic Resistance and Applications in Human Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive, prevalent, and distinct subtype of breast cancer characterized by high recurrence rates and poor clinical prognosis, devoid of both predictive markers and potential therapeutic targets. MicroRNAs (miRNA/miR) are a family of small, endogenous, non-coding, single-stranded regulatory RNAs that bind to the 3′-untranslated region (3′-UTR) complementary sequences and downregulate the translation of target mRNAs as post-transcriptional regulators. Dysregulation miRNAs are involved in broad spectrum cellular processes of TNBC, exerting their function as oncogenes or tumor suppressors depending on their cellular target involved in tumor initiation, promotion, malignant conversion, and metastasis. In this review, we emphasize on masses of miRNAs that act as oncogenes or tumor suppressors involved in epithelial–mesenchymal transition (EMT), maintenance of stemness, tumor invasion and metastasis, cell proliferation, and apoptosis. We also discuss miRNAs as the targets or as the regulators of dysregulation epigenetic modulation in the carcinogenesis process of TNBC. Furthermore, we show that miRNAs used as potential classification, prognostic, chemotherapy and radiotherapy resistance markers in TNBC. Finally, we present the perspective on miRNA therapeutics with mimics or antagonists, and focus on the challenges of miRNA therapy. This study offers an insight into the role of miRNA in pathology progression of TNBC.

Up-regulation of DDIT4 predicts poor prognosis in acute myeloid leukaemia

The mammalian target of rapamycin (mTOR) inhibitor, DNA damage inducible transcript 4 (DDIT4), has inducible expression in response to various cellular stresses. In multiple malignancies, studies have shown that DDIT4 participates in tumorigenesis and impacts patient survival. We aimed to study the prognostic value of DDIT4 in acute myeloid leukaemia (AML), which is currently unclear. Firstly, The Cancer Genome Atlas was screened for AML patients with complete clinical characteristics and DDIT4 expression data. A total of 155 patients were included and stratified according to the treatment modality and the median DDIT4 expression levels. High DDIT4 expressers had shorter overall survival (OS) and event‐free survival (EFS) than the low expressers among the chemotherapy‐only group (all P < .001); EFS and OS were similar in the high and low DDIT4 expressers of the allogeneic haematopoietic stem cell transplantation (allo‐HSCT) group. Furthermore, in the DDIT4^high group, patients treated with allo‐HSCT had longer EFS and OS than those who received chemotherapy alone (all P < .01). In the DDIT4^low group, OS and EFS were similar in different treatment groups. Secondly, we analysed two other cytogenetically normal AML (CN‐AML) cohorts derived from the Gene Expression Omnibus database, which confirmed that high DDIT4 expression was associated with poorer survival. Gene Ontology (GO) enrichment analysis showed that the genes related to DDIT4 expression were mainly concentrated in the acute and chronic myeloid leukaemia signalling pathways. Collectively, our study indicates that high DDIT4 expression may serve as a poor prognostic factor for AML, but its prognostic effects could be outweighed by allo‐HSCT.

Dysregulated MicroRNA Fingerprints and Methylation Patterns in Hepatocellular Carcinoma, Cancer Stem Cells, and Mesenchymal Stem Cells

Hepatocellular carcinoma (HCC) is one of the top causes of cancer mortality worldwide. Although HCC has been researched extensively, there is still a need for novel and effective therapeutic interventions. There is substantial evidence that initiation of carcinogenesis in liver cirrhosis, a leading cause of HCC, is mediated by cancer stem cells (CSCs). CSCs were also shown to be responsible for relapse and chemoresistance in several cancers, including HCC. MicroRNAs (miRNAs) constitute important epigenetic markers that regulate carcinogenesis by acting post-transcriptionally on mRNAs, contributing to the progression of HCC. We have previously shown that co-culture of cancer cells with mesenchymal stem cells (MSCs) could induce the reprogramming of MSCs into CSC-like cells. In this review, we evaluate the available data concerning the epigenetic regulation of miRNAs through methylation and the possible role of this regulation in stem cell and somatic reprogramming in HCC.

Bioinformatics prediction and experimental validation of a novel microRNA: hsa-miR-B43 within human CDH4 gene with a potential metastasis-related function in breast cancer

As a class of short noncoding RNAs, microRNAs (miRNAs) play a key role in the modulation of gene expression. Although, the regulatory roles of currently identified miRNAs in various cancer types including breast cancer have been well documented, there are many as yet undiscovered miRNAs. The aim of the current study was to bioinformatically reanalyze a list of 189 potentially new miRNAs introduced in a previously published paper (PMID: 21346806) and experimentally explore the existence and function of a candidate one: hsa-miR-B43 in breast cancer cells. The sequences of 189 potential miRNAs were re-checked in the miRbase database. Genomic location and conservation of them were assessed with the University of California Santa Cruz (UCSC) genome browser. SSC profiler, RNAfold, miRNAFold, MiPred, and FOMmiR bioinformatics tools were furthermore utilized to explore potential hairpin structures and differentiate real miRNA precursors from pseudo ones. hsa-miR-B43 was finally selected as one of the best candidates for laboratory verification. The expression and function of hsa-miR-B43 were examined by real-time polymerase chain reaction, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, and wound-healing assays. DIANA-microT, RNAhybrid and Enrichr tools were used to predict the miRNA target genes and for further enrichment analysis. We could detect the exogenous and endogenous expression of hsa-miR-B43, as a real novel miRNA, in cancer cell lines. Gene Ontology enrichment, pathway analysis and wound-healing assay results furthermore confirmed that a metastasis-related function may be assigned to hsa-miR-B43. Our results introduced hsa-miR-B43, as a novel functional miRNA, which might play a role in the metastatic process. Further studies will be necessary to completely survey the existence and function of hsa-miR-B43 in other cancer types.

MicroRNAs hsa-miR-495-3p and hsa-miR-486-5p suppress basal and rifampicin-induced expression of human sulfotransferase 2A1 (SULT2A1) by facilitating mRNA degradation

Drug metabolizing enzymes mediate biotransformation of drugs and play an essential role in drug efficacy and toxicity. Human sulfotransferases are a superfamily of Phase II detoxification enzymes that metabolize a wide spectrum of endogenous compounds and xenobiotics. SULT2A1 is one of the most abundant hepatic sulfotransferases and it catalyzes the sulfate conjugation of many endogenous substrates, such as bile acids and steroids. In the current study, we utilized a systematic approach by combining a series of computational analyses and in vitro methods to identify miRNAs that repress SULT2A1 expression post-transcriptionally. Our in silico analyses predicted miRNA response elements for hsa-miR-495-3p and hsa-miR-486-5p within the 3'-UTR of SULT2A1 mRNA and the levels of these miRNAs were inversely correlated with that of SULT2A1 mRNA in human liver. Using fluorescence-based RNA electrophoretic mobility shift assays, we found that hsa-miR-495-3p and hsa-miR-486-5p interacted directly with the SULT2A1 3'-UTR. The activity of a luciferase reporter gene construct containing sequences from the SULT2A1 3-UTR was suppressed by hsa-miR-486-5p and hsa-miR-495-3p. Furthermore, gain- and loss-of-function assays demonstrated that hsa-miR-486-5p and hsa-miR-495-3p negatively modulate basal and rifampicin-induced expression of SULT2A1 in HepG2 cells by decreasing mRNA stability.

Long non-coding RNA CRNDE promotes cell apoptosis by suppressing miR-495 in inflammatory bowel disease

OBJECTIVE

This article aims to investigate the mechanism of microRNA-495 (miR-495) and long non-coding RNA CRNDE on the apoptosis of colonic epithelial cells in inflammatory bowel diseases (IBDs).

METHODS

The mouse model of IBD was induced by dextran sulfate sodium (DSS), and human colonic epithelial cell lines (HT-29, LOVO, and Caco-2) were treated with DSS, and received cell transfection. RNA interference was used to down-regulate CRNDE expression.

RESULTS

CRNDE and SOCS1 were highly expressed, but miR-495 was lowly expressed in the DSS-induced colitis tissues and colonic epithelial cell lines. Interference of CRNDE inhibited cell apoptosis of DSS-induced colonic epithelial cells. The interaction between CRNDE and miR-495 was confirmed by RNA immunoprecipitation and RNA pull-down assay. The target relationship between miR-495 and SOCS1 was confirmed by the luciferase reporter assay. CRNDE promoted DSS-induced colonic epithelial cell apoptosis via miR-495/SOCS1. CRNDE interference in DSS-induced colitis mouse model alleviated clinical manifestations of IBD.

CONCLUSIONS

Our findings demonstrated that CRNDE promoted DSS-induced colonic epithelial cell apoptosis via suppressing miR-495 and increasing SOCS1, indicating CRNDE as a novel target of treating IBD.

miR-496, miR-1185, miR-654, miR-3183 and miR-495 are downregulated in colorectal cancer cells and have putative roles in the mTOR pathway

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression by suppressing the target mRNA and inhibiting translation in order to regulate multiple biological processes. miRNAs play important roles as oncogenes or tumor suppressors in the development of various types of human cancer. The regulation of mammalian target of rapamycin (mTOR) by miRNAs has been studied in several types of cancer, including colorectal cancer (CRC). However, to the best of our knowledge, only limited information regarding the function of miRNAs in human CRC is available. In the present study, the expression of 22 miRNAs in CRC cell lines were investigated in regard to key genes in the mTOR pathway. Initially, it was revealed that mTOR, regulatory-associated protein of mTOR complex I and rapamycin-intensive companion of mTOR were overexpressed in CRC cell lines when compared with a normal colorectal cell line. Subsequently, putative miRNA-mRNA associations were identified via multiple miRNA target prediction programs. The expression levels for the candidate miRNAs were validated using quantitative real-time polymerase chain reaction. Expression analysis revealed that, among 20 miRNAs, five miRNAs (miR-496, miR-1185, miR-654, miR-3183 and miR-495) exhibited significant downregulation in association with the mTOR signaling pathway. Taken together, the results from the present study suggest that several miRNAs that are associated with CRC, with possible roles in mTOR signaling, may have potential therapeutic or diagnostic benefits in CRC treatment.

Non-coding RNAs as potential therapeutic targets in breast cancer

Paradigm shifting studies especially involving non-coding RNAs (ncRNAs) during last few decades have significantly changed the scientific perspectives regarding the complexity of cellular signalling pathways. Several studies have shown that the non-coding RNAs, initially ignored as transcriptional noise or products of erroneous transcription; actually regulate plethora of biological phenomena ranging from developmental processes to various diseases including cancer. Current strategies that are employed for the management of various cancers including that of breast fall short when their undesired side effects like Cancer Stem Cells (CSC) enrichment, low recurrence-free survival and development of drug resistance are taken into consideration. This review aims at exploring the potential role of ncRNAs as therapeutics in breast cancer, by providing a comprehensive understanding of their mechanism of action and function and their crucial contribution in regulating various aspects of breast cancer progression such as cell proliferation, angiogenesis, EMT, CSCs, drug resistance and metastasis. In addition, we also provide information about various strategies that can be employed or are under development to explore them as potential moieties that may be used for therapeutic intervention in breast cancer.

Inhibition of miR-495 Improves Both Vascular Remodeling and Angiogenesis in Pulmonary Hypertension

BACKGROUND AND AIMS

Pulmonary hypertension (PH) is a chronic progressing vascular disease characterized by pulmonary arteriole remodeling and loss of pulmonary microvasculature. The aim of this study was to investigate a potential role for the miR-495 in PH pathogenesis and to explore its therapeutic potential in PH.

METHODS

Male C57BL/6J mice were injected with SU5416 weekly during 3 weeks of exposure to 10% oxygen to cause PH. We first tested the effects of adeno-associated virus 9 (AAV9) delivery which was specifically designed to block miR-495 in the lungs of the PH model. Then, the biological function of miR-495 was analyzed in cultured pulmonary arterial endothelial cells (PAECs) under hypoxic condition.

RESULTS

The inhibition of miR-495 improves hemodynamics and vascular remodeling in PH. At the same time, these effects were associated with increases in angiogenic transcription factor VEZF1 and marked upregulation of other angiogenic genes such as Angpt-1 and IGF1. In vitro, cultured mouse PAECs were transfected with miR-495 inhibitor or miR-495 mimics. Both the flow cytometry results and CCK8 assay showed that miR-495 inhibitor increased the percentage of cells in the G2/M+S phase, and the wound healing assays indicated that the migration capacity of PAECs transfected with miR-495 inhibitor was increased compared to the inhibitor-NC cells.

CONCLUSIONS

Our results indicate that AAV9-TuD-miR-495 delivery improves hemodynamic and pulmonary vascular structural changes in PH mice.

Effect of miR-495 on lower extremity deep vein thrombosis through the TLR4 signaling pathway by regulation of IL1R1

Lower extremity deep vein thrombosis (LEDVT), a common peripheral vascular disease caused by a blood clot in a deep vein is usually accompanied by swelling of the lower limbs. MicroRNAs (miRs) have been reported to play roles in LEDVT. We aimed to investigate the effect of miR-495 on LEDVT via toll-like receptor 4 (TLR4) signaling pathway through interleukin 1 receptor type 1 (IL1R1). LEDVT mouse model was established, and the femoral vein (FV) tissues were collected to detect expressions of miR-495, IL1R1, and TLR4 signaling-related genes. The expressions of both CD31 and CD34 (markers for endothelial progenitor cells) in the FV endothelial cells as well as the proportion of CD31⁺/CD34⁺ cells in peripheral blood were measured in order to evaluate thrombosis. The effect of miR-495 on cell viability, cell cycle, and apoptosis was analyzed. IL1R1 was confirmed as the target gene of miR-495. Besides, inhibiting the miR-495 expression could increase IL1R1 expression along with activating the TLR4 signaling pathway. The total number of the leukocytes along with the ratio of weight to length of thrombus in the FV tissue showed an increase. The overexpression of miR-495 could promote FV endothelial cell viability. By injecting agomiR-495 and antagomiR-495 in vivo, the number of leukocytes in the FV tissues and the ratio of weight to length of thrombus were significantly decreased in the mice injected with the overexpressed miR-495, and the IL1R1/TLR4 signaling pathway was inhibited. Collectively, overexpressed miR-495 directly promotes proliferation while simultaneously inhibiting apoptosis of FV endothelial cells, alleviating FV thrombosis by inhibiting IL1R1 via suppression of TLR4 signaling pathway.