MiR-125b regulates the proliferation and metastasis of triple negative breast cancer cells via the Wnt/β-catenin pathway and EMT

MiR-125b targeted regulation of MKNK2 inhibits multiple myeloma proliferation and invasion

BACKGROUND

An increasing number of studies demonstrate that abnormal miRNA expression contributes to the advancement of many tumors. Nonetheless, the potential role of miR-125b in multiple myeloma (MM) remains unknown.

OBJECTIVES

To explore the potential effects and mechanism of miR-125b in MM.

METHODS

Real-time quantitative PCR was used to measure the expression levels of miR-125b and MKNK2 in a variety of MM samples. Colony formation and cell counting Kit-8 (CCK-8) assays were used to assess cell proliferation, the transwell assay was used to evaluate the cell invasion capability, and dual luciferase reporter gene assay and Western blot were used to examine the interaction between miR-125b and MKNK2.

RESULTS

The levels of miR-125b were higher in MM tissue samples, alongside increased expression of MKNK2. There was a negative correlation between MKNK2 and miR-125b expression in MM tissues. MKNK2 was identified as a direct target gene of miR-125b in MM cells. Overexpression of miR-125b suppressed MM cell growth, colony formation, and invasion. In addition, MKNK2 was found to mediate the effects of miR-125b on cell proliferation, colony formation, and invasion in MM.

CONCLUSIONS

miR-125b acts as a suppressive factor in multiple myeloma and can affect the malignant behavior of MM by regulating the expression of MKNK2.

The Role of MicroRNAs in Breast Cancer and the Challenges of Their Clinical Application

MicroRNAs (miRNAs) constitute a subclass of non-coding RNAs that exert substantial influence on gene-expression regulation. Their tightly controlled expression plays a pivotal role in various cellular processes, while their dysregulation has been implicated in numerous pathological conditions, including cancer. Among cancers affecting women, breast cancer (BC) is the most prevalent malignant tumor. Extensive investigations have demonstrated distinct expression patterns of miRNAs in normal and malignant breast cells. Consequently, these findings have prompted research efforts towards leveraging miRNAs as diagnostic tools and the development of therapeutic strategies. The aim of this review is to describe the role of miRNAs in BC. We discuss the identification of oncogenic, tumor suppressor and metastatic miRNAs among BC cells, and their impact on tumor progression. We describe the potential of miRNAs as diagnostic and prognostic biomarkers for BC, as well as their role as promising therapeutic targets. Finally, we evaluate the current use of artificial intelligence tools for miRNA analysis and the challenges faced by these new biomedical approaches in its clinical application. The insights presented in this review underscore the promising prospects of utilizing miRNAs as innovative diagnostic, prognostic, and therapeutic tools for the management of BC.

MicroRNAs: The key players regulating the crosstalk between Hippo and Wnt/β-catenin pathways in breast cancer

Breast Cancer has the highest burden in females worldwide and is predicted to increase by many folds with increasing lifestyle related risk factors, genetic mutations, and an aging population. The Hippo signalling and Wnt signalling pathways were identified as important signal transducers involved in maintaining organ development, tissue homeostasis, cell proliferation and apoptosis. microRNAs are short nucleotide sequences which act as regulatory components driving signal transductions in most cancers and can serve as both diagnostic and prognostic markers. Several reports have implicated that deregulated Hippo as well as Wnt signalling mediated by miRNAs together drive tumorigenesis, metastases and chemoresistance in breast cancer. Recent evidences on a crosstalk between Hippo and Wnt components elucidated how these pathways might be synchronized to have overlapping functions to promote tumorigenesis. Since miRNAs are demonstrated to target most of the components in both the pathways, in this review, we talk about the crosstalk between Hippo and Wnt signalling pathways and the potential microRNAs that might regulate the interplay between the two pathways in breast cancer, which has not been explored earlier.

Deciphering the Enigmatic Influence: Non-Coding RNAs Orchestrating Wnt/β-Catenin Signaling Pathway in Tumor Progression

Dysregulated expression of specific non-coding RNAs (ncRNAs) has been strongly linked to tumorigenesis, cancer progression, and therapeutic resistance. These ncRNAs can act as either oncogenes or tumor suppressors, thereby serving as valuable diagnostic and prognostic markers. Numerous studies have implicated the participation of ncRNAs in the regulation of diverse signaling pathways, including the pivotal Wnt/β-catenin signaling pathway that is widely acknowledged for its pivotal role in embryogenesis, cellular proliferation, and tumor biology control. Recent emerging evidence has shed light on the capacity of ncRNAs to interact with key components of the Wnt/β-catenin signaling pathway, thereby modulating the expression of Wnt target genes in cancer cells. Notably, the activity of this pathway can reciprocally influence the expression levels of ncRNAs. However, comprehensive analysis investigating the specific ncRNAs associated with the Wnt/β-catenin signaling pathway and their intricate interactions in cancer remains elusive. Based on these noteworthy findings, this review aims to unravel the intricate associations between ncRNAs and the Wnt/β-catenin signaling pathway during cancer initiation, progression, and their potential implications for therapeutic interventions. Additionally, we provide a comprehensive overview of the characteristics of ncRNAs and the Wnt/β-catenin signaling pathway, accompanied by a thorough discussion of their functional roles in tumor biology. Targeting ncRNAs and molecules associated with the Wnt/β-catenin signaling pathway may emerge as a promising and effective therapeutic strategy in future cancer treatments.

Biological functions and molecular interactions of Wnt/β-catenin in breast cancer: Revisiting signaling networks

Changes in lifestyle such as physical activity and eating habits have been one of the main reasons for development of various diseases in modern world, especially cancer. However, role of genetic factors in initiation of cancer cannot be ignored and Wnt/β-catenin signaling is such factor that can affect tumor progression. Breast tumor is the most malignant tumor in females and it causes high mortality and morbidity around the world. The survival and prognosis of patients are not still desirable, although there have been advances in introducing new kinds of therapies and diagnosis. The present review provides an update of Wnt/β-catenin function in breast cancer malignancy. The upregulation of Wnt is commonly observed during progression of breast tumor and confirms that tumor cells are dependent on this pathway Wnt/β-catenin induction prevents apoptosis that is of importance for mediating drug resistance. Furthermore, Wnt/β-catenin signaling induces DNA damage repair in ameliorating radio-resistance. Wnt/β-catenin enhances proliferation and metastasis of breast tumor. Wnt/β-catenin induces EMT and elevates MMP expression. Furthermore, Wnt/β-catenin participates in tumor microenvironment remodeling and due to its tumor-promoting factor, drugs for its suppression have been developed. Different kinds of upstream mediators Wnt/β-catenin signaling in breast cancer have been recognized that their targeting is a therapeutic approach. Finally, Wnt/β-catenin can be considered as a biomarker in clinical trials.

Inhibition of WNT signaling by conjugated microRNA nano-carriers: A new therapeutic approach for treating triple-negative breast cancer a perspective review

Triple-Negative Breast Cancer is the most aggressive form and accounts the 15%-25% of all breast cancer. Receptors are absent in triple-negative breast cancer, which makes them unresponsive to the current hormonal therapies. The patients with TNBC are left with the option of cytotoxic chemotherapy. The Wnt pathways are connected to cancer, and when activated, they result in mammary hyperplasia and tumors. The tumor suppressor microRNAs can block tumor cell proliferation, invasion, and migration, lead to cancer cell death, and are also known to down-regulate the WNT signaling. Nanoparticles with microRNA have been seen to be more effective when compared with their single release. In this review, we have tried to understand how Wnt signaling plays a crucial role in TNBC, EMT, metastasis, anti-drug resistance, and regulation of Wnt by microRNA. The role of nano-carriers in delivering micro-RNA. The clinical biomarkers, including the present state-of-the-art, involve novel pathways of Wnt.

New progress in the role of microRNAs in the diagnosis and prognosis of triple negative breast cancer

Triple negative breast cancer is distinguished by its high malignancy, aggressive invasion, rapid progression, easy recurrence, and distant metastases. Additionally, it has a poor prognosis, a high mortality, and is unresponsive to conventional endocrine and targeted therapy, making it a challenging problem for breast cancer treatment and a hotspot for scientific research. Recent research has revealed that certain miRNA can directly or indirectly affect the occurrence, progress and recurrence of TNBC. Their expression levels have a significant impact on TNBC diagnosis, treatment and prognosis. Some miRNAs can serve as biomarkers for TNBC diagnosis and prognosis. This article summarizes the progress of miRNA research in TNBC, discusses their roles in the occurrence, invasion, metastasis, prognosis, and chemotherapy of TNBC, and proposes a treatment strategy for TNBC by interfering with miRNA expression levels.

Role of microRNA/lncRNA Intertwined With the Wnt/β-Catenin Axis in Regulating the Pathogenesis of Triple-Negative Breast Cancer

Objective (s): In this mini-review, we aimed to discuss the Wnt/β-catenin signaling pathway modulation in triple-negative breast cancer, particularly the contribution of lncRNAs and miRNAs in its regulation and their possible entwining role in breast cancer pathogenesis, proliferation, migration, or malignancy.

Background: Malignant tumor formation is very high for breast cancer in women and is a leading cause of death all over the globe. Among breast cancer subtypes, triple-negative breast cancer is rife in premenopausal women, most invasive, and prone to metastasis. Complex pathways are involved in this cancer’s pathogenesis, advancement, and malignancy, including the Wnt/β-catenin signaling pathway. This pathway is conserved among vertebrates and is necessary for sustaining cell homeostasis. It is regulated by several elements such as transcription factors, enhancers, non-coding RNAs (lncRNAs and miRNAs), etc.

Methods: We evaluated lncRNAs and miRNAs differentially expressed in triple-negative breast cancer (TNBC) from the cDNA microarray data set literature survey. Using in silico analyses combined with a review of the current literature, we anticipated identifying lncRNAs and miRNAs that might modulate the Wnt/β-catenin signaling pathway.

Result: The miRNAs and lncRNAs specific to triple-negative breast cancer have been identified based on literature and database searches. Tumorigenesis, metastasis, and EMT were all given special attention. Apart from cross-talk being essential for TNBC tumorigenesis and treatment outcomes, our results indicated eight upregulated and seven downregulated miRNAs and 19 upregulated and three downregulated lncRNAs that can be used as predictive or diagnostic markers. This consolidated information could be useful in the clinic and provide a combined literature resource for TNBC researchers working on the Wnt/β-catenin miRNA/lncRNA axis.

Conclusion: In conclusion, because the Wnt pathway and miRNAs/lncRNAs can modulate TNBC, their intertwinement results in a cascade of complex reactions that affect TNBC and related processes. Their function in TNBC pathogenesis has been highlighted in molecular processes underlying the disease progression.

Complex cross-talk between EZH2 and miRNAs confers hallmark characteristics and shapes the tumor microenvironment

Cancer epigenetic mechanisms support the acquisition of hallmark characteristics during oncogenesis. EZH2 - an important histone methyltransferase that writes histone H3 lysine 27 trimethylation marks - is known to be dysregulated in cancer cells. However, the interactions between EZH2 and miRNAs that form a complex network of cross-talk and reciprocal regulation that enable cancer cells to acquire hallmark characteristics have been relatively poorly appreciated. The specific functions of EZH2 appear to be regulated by a vast array of miRNAs, which direct EZH2 toward regulation over the development of specific hallmark characteristics. This review discusses recent advances in the understanding of EZH2, focusing on its collaboration with miRNAs to orchestrate oncogenesis. These epigenetic processes promote the evasion of apoptosis/cell cycle arrest, cellular dedifferentiation and the establishment of a tumor microenvironment that facilitates local cancer cell invasion, anti-cancer drug resistance and evasion of the immune response.

Overexpression of lncRNA SLC16A1-AS1 Suppresses the Growth and Metastasis of Breast Cancer via the miR-552-5p/WIF1 Signaling Pathway

Background

Breast cancer (BC) is the most common cancer and the fifth leading cause of cancer mortality with 685,000 deaths worldwide in 2020. Long non-coding RNAs (lncRNAs) are critical in BC carcinogenesis and progression. However, the functional roles and mechanisms of SLC16A1-AS1 in BC are unknown.

Methods

The expression profile of SLC16A1-AS1 in BC patients was investigated using data from The Cancer Genome Atlas (TCGA) database and checked in 80 BC patients, followed by analyzing the prognostic value of SLC16A1-AS1 in the 80 BC patients. The biological functions of SLC16A1-AS1 were further examined in vivo and in vitro after overexpression of SLC16A1-AS1 in BC cells. Possible binding sites between SLC16A1-AS1 and miR-552-5p were predicted by miRDB and those between miR-552-5p and Wnt inhibitory factor-1 (WIF1) were predicted by miRanda, which were confirmed using dual-luciferase reporter assay with mutation. Spearman correlation assay was applied to evaluate the association between genes. Rescue experiments were further applied to investigate the molecular mechanisms involved.

Results

Lower SLC16A1-AS1 expression in BC tissues was related to poor prognosis of BC patients. Upregulation of SLC16A1-AS1 suppressed BC cell viability, colony formation, invasion, and migration in vitro and growth in vivo via sponging miR-552-5p to release WIF1.

Conclusion

SLC16A1-AS1 is a tumor suppressor in BC, and lower SLC16A1-AS1 expression is an indicator of poor prognosis in BC patients. SLC16A1-AS1 inhibits BC carcinogenesis and progression via the SLC16A1-AS1/miR-552-5p/WIF1 pathway. SLC16A1-AS1 represents a novel diagnostic, therapeutic, and prognostic target for BC management.

The functional significance and cross-talk of non-coding RNAs in triple negative and quadruple negative breast cancer

One of the leading causes of cancer-related deaths worldwide is breast cancer, among which triple-negative breast cancer (TNBC) is the most malignant and lethal subtype. This cancer accounts for 10-20% of all breast cancer deaths. Proliferation, tumorigenesis, and prognosis of TNBC are affected when the androgen receptor (AR) is not expressed, and it is classified as quadruple negative breast cancer (QNBC). Non-coding RNAs, such as microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), play a significant role in tumorigenesis by virtue of their oncogenic and tumor-suppressive properties. To regulate tumorigenesis, miRNAs interact with their target mRNAs and modulate their expression, whereas lncRNAs can either act alone or interact with miRNAs or other molecules through various signaling pathways. Conversely, circRNAs regulate tumorigenesis by acting as miRNA sponges predominantly. Recently, non-coding RNAs were studied comprehensively for their roles in tumor proliferation, progression, and metastasis. As a result of existing studies and research progress, non-coding RNAs have been implicated in TNBC, necessitating their use as biomarkers for future diagnostic applications. In this review, the non-coding RNAs are explicitly implicated in the regulation of breast cancer, and their cross-talk between TNBC and QNBC is also discussed.

Contribution of miRNAs in the Pathogenesis of Breast Cancer

Breast cancer is the most frequently diagnosed cancer among females. Gene expression profiling methods have shown the deregulation of several genes in breast cancer samples and have confirmed the heterogeneous nature of breast cancer at the genomic level. microRNAs (miRNAs) are among the recently appreciated contributors in breast carcinogenic processes. These small-sized transcripts have been shown to partake in breast carcinogenesis through modulation of apoptosis, autophagy, and epithelial-mesenchymal transition. Moreover, they can confer resistance to chemotherapy. Based on the contribution of miRNAs in almost all fundamental aspects of breast carcinogenesis, therapeutic intervention with their expression might affect the course of this disorder. Moreover, the presence of miRNAs in the peripheral blood of patients potentiates these transcripts as tools for non-invasive diagnosis of breast cancer.

Investigation of the efficacy of paclitaxel on some miRNAs profiles in breast cancer stem cells

Understanding of the functions of microRNAs in breast cancer and breast cancer stem cells have been a hope for the development of new molecular targeted therapies. Here, it is aimed to investigate the differences in the expression levels of let-7a, miR-10b, miR-21, miR-125b, miR-145, miR-155, miR-200c, miR-221, miR-222 and miR-335, which associated with gene and proteins in MCF-7 (parental) and MCF-7s (Mammosphere/stem cell-enriched population/CD44+/CD24-cells) cells treated with paclitaxel. MCF-7s were obtained from parental MCF-7 cells. Cytotoxic activity of paclitaxel was determined by ATP assay. Total RNA isolation and cDNA conversion were performed from the samples. Changes in expression levels of miRNAs were examined by RT-qPCR. Identified target genes and proteins of miRNAs were analyzed with RT-qPCR and western blot analysis, respectively. miR-125b was significantly expressed (2.0946-fold; p = 0.021) in MCF-7s cells compared to control after treatment with paclitaxel. Downregulation of SMO, STAT3, NANOG, OCT4, SOX2, ERBB2 and ERBB3 and upregulation of TP53 genes were significant after 48 h treatment in MCF-7s cells. Protein expressions of SOX2, OCT4, SMAD4, SOX2 and OCT4 also decreased. Paclitaxel induces miR-125b expression in MCF-7s cells. Upregulation of miR-125b may be used as a biomarker for the prediction of response to paclitaxel treatment in breast cancer.

MiR-125b Inhibits Cell Proliferation and Induces Apoptosis in Human Colon Cancer SW480 Cells via Targeting STAT3

BACKGROUND

Colon cancer is one of the most common types of cancer worldwide. Multiple studies have unveiled the key role of microRNAs (miRNAs) in the development of various types of cancer. However, the mechanism of action of miR-125b in the development and progression of colon cancer remains unknown.

OBJECTIVE

In this study, we explored the association of miR-125b and signal transducer and activator of transcription 3 (STAT3) and its role in the proliferation and apoptosis of SW480 colon cancer cells.

METHODS

The miR-125b expression in NCM460, SW480, HT29, and HCT8 cells was detected using quantitative real-time polymerase chain reaction (qRT-PCR). SW480 cells were transfected with lentiviruses of GFP-miR-125b and GFP-NC to establish a stable miR-125b overexpression colon cancer cell model and a control model. The targeting relationship between miR-125b and STAT3 was analyzed using bioinformatics and verified by the dual-luciferase reporter gene assay. Cell proliferation and apoptosis were assessed using the Cell Counting Kit-8 assay and TUNEL staining. The expression levels of STAT3, Bcl-2, and Bax were analyzed using Western blot analysis.

RESULTS

It was found that the relative mRNA expression of miR-125b was decreased in SW480, HT29, and HCT8 cells compared with that in NCM460 cells (P<0.05). The luciferase reporter gene assay confirmed that miR-125b downregulated the STAT3 gene expression (P<0.05). Overexpression of miR-125b inhibited proliferation and promoted apoptosis in SW480 colon cancer cells and was accompanied by upregulated Bax expression and downregulated Bcl-2 expression (P<0.05). Re-expression of STAT3 promoted cell proliferation and inhibited cell apoptosis, whereas Bcl-2 expression increased, and Bax expression decreased (P<0.05).

CONCLUSION

The miR-125b regulates the expression of Bax and Bcl-2 by downregulating the expression of STAT3, thereby inhibiting proliferation and inducing apoptosis of SW480 colon cancer cells.

LncRNA MALAT1 Promote Cell Proliferation and Invasion by Sponging miR-125b to Modulate HMGA1 Expression in Laryngocarcinoma

BACKGROUND

Laryngocarcinoma is the most frequent head and neck malignant tumor. MALAT1 have a role in promoting cell proliferation and metastasis in several tumors. This research aimed to investigate the great roles of MALAT1in laryngocarcinoma.

METHODS

Overall, 54 cases of laryngocarcinoma tissues pathological specimens and paracancerous tissues were collected by surgical resection from the Department of Otolaryngology-Head and Neck Surgery at the Shandong Provincial Hospital affiliated to Shandong University, China from Jan 2012 to Oct 2015. The microRNA and protein levels of genes were evaluated by RT-qPCR and western blot. The proliferative and invasive ability were calculated usingCCK8 and transwell assays. Kaplan-Meier method was used to assess the survival of laryngocarcinoma patients.

RESULTS

In laryngocarcinoma tissues and cells, lncRNA MALAT1 expression was significantly increased compared to normal tissues and cells. LncRNA MALAT1 promotes proliferation and migration of laryngocarcinoma cells. LncRNA MALAT1 upregulates HMGA1 expression by acting as a competitive endogenous RNA (ceRNA) for miR-125b. Rescue experiments showed that microRNA-125b inhibitor reversed the change in cell viability and invasion induced by sh-MALAT1. Down regulation of lncRNA MALAT1 inhibits laryngocarcinoma proliferation and invasion by modulating miR-125b/HMGA1.

CONCLUSION

LncRNA MALAT1 promotes the development of laryngocarcinoma by regulating the expression level of HMGA1 by acting as a miR-125b ceRNA and may be considered as a new strategy for the development of laryngocarcinoma.

Curcumol increases the sensitivity of colon cancer to 5-FU by regulating Wnt/β-catenin signaling

Background

5-fluorouracil (5-FU) resistance is the leading cause of treatment failure in colon cancer. Combination therapy is an effective strategy to inhibit cancer cells and prevent drug resistance. Therefore, we studied the antitumor effect of curcumol alone or combined with 5-FU on human colon cancer drug-resistant cells.

Methods

The 5-FU resistant HCT116 cell line (HCT116/5-FU) was established by repeated exposure to gradually increasing concentrations of 5-FU; Cell viability was measured by cell counting kit-8 (CCK-8); apoptosis rate of HCT116 cells was detected using Annexin V-fluorescein isothiocyanate (FITC) assay kit; cell proliferation and invasion were detected using colony formation assays, wound healing assay and transwell invasion assays; activity of transplanted tumor in vivo in specific pathogen free (SPF) BALB/c nude mice (6 weeks old, male) was monitored by bioluminescence imaging, immunohistochemistry and western blot analysis.

Results

Our study showed the potent antitumor effect of curcumol by induction of apoptosis, inhibition of proliferation, invasion, migration, and improvement of the therapeutic efficacy of 5-FU toward human colon cancer HCT116 cells. From our results, curcumol could chemosensitize 5-FU-resistant HCT116 cells. The combination of curcumol and 5-FU exerted a synergistic inhibitory effect on the induction of apoptosis. Also, this combination inhibited the proliferation, invasion, and migration of both chemo-resistant and sensitive cells. Curcumol treatment decreased multidrug resistance-associated protein 2 (MRP-2), P-glycoprotein (P-gp), survivin, and β-catenin expression, which correlated with multidrug resistance (MDR) and the target genes of Wnt/β-catenin. It significantly increased the p-β-catenin level and Bad/Bcl-2 ratio in HCT116/5-FU cells compared with 5-FU treatment. In vivo, curcumol significantly inhibited the growth of transplanted tumors and the expression of Ki-67, proliferating cell nuclear antigen (PCNA), and vascular endothelial growth factor (VEGF) in colon cancer cells.

Conclusions

Curcumol as a potential chemotherapeutic agent combined with 5-FU can overcome colon cancer resistance.

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.

The Impact of Non-coding RNAs in the Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is a course of action that enables a polarized epithelial cell to undertake numerous biochemical alterations that allow it to adopt features of mesenchymal cells such as high migratory ability, invasive properties, resistance to apoptosis, and importantly higher-order formation of extracellular matrix elements. EMT has important roles in implantation and gastrulation of the embryo, inflammatory reactions and fibrosis, and transformation of cancer cells, their invasiveness and metastatic ability. Regarding the importance of EMT in the invasive progression of cancer, this process has been well studies in in this context. Non-coding RNAs (ncRNAs) have been shown to exert critical function in the regulation of cellular processes that are involved in the EMT. These processes include regulation of some transcription factors namely SNAI1 and SNAI2, ZEB1 and ZEB2, Twist, and E12/E47, modulation of chromatin configuration, alternative splicing, and protein stability and subcellular location of proteins. In the present paper, we describe the influence of ncRNAs including microRNAs and long non-coding RNAs in the EMT process and their application as biomarkers for this process and cancer progression and their potential as therapeutic targets.

Increased expression of MUSASHI1 in epithelial breast cancer cells is due to down regulation of miR-125b

Background

Musashi1 (MSI1) is an oncogenic protein with a crucial role in the proliferation and characteristics of the epithelial cells in breast cancer. The change in expression of MSI1 has a role in solid tumor progression. There are different factors that regulate MSI1 expression in various cancer tissues including microRNAs which are considered as one of the most important of these factors. The aim of our study is identification of the molecular cause of maximal expression of MSI1 in epithelial breast cancer cell lines.

Results

Among predicted microRNAs, miR-125b, miR-637 and miR-802 were able to significantly reduce the luciferase activity. In addition, the relative expression of these three miRNAs were measured in the cancerous cell lines that results showed a significant reduction in expression of all microRNAs. On the other hand, only the overexpression of miR-125b caused a change in the expression pattern of MSI1 in breast epithelial cancer cell lines. Accordingly, our results demonstrated that the exogenous expression of miR-125b decreased not only the MSI1 protein but also expression of epithelial markers in breast cancer cells.

Conclusions

The results of luciferase reporter assay showed that MSI1 is a direct target for miR-125b in epithelial breast cancer cells. Moreover, higher amount of MSI1 in those cell lines seems due to the reduced amount of miR-125b, which is responsible for epithelial features of those kinds of cancer cells. Therefore, the modulation of miR-125b may be a potential approach to help to combat against epithelial breast tumors.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12860-021-00348-8.

Essential functions of miR-125b in cancer

MicroRNAs (miRNAs) are small and highly conserved non-coding RNAs that silence target mRNAs, and compelling evidence suggests that they play an essential role in the pathogenesis of human diseases, especially cancer. miR-125b, which is the mammalian orthologue of the first discovered miRNA lin-4 in Caenorhabditis elegans, is one of the most important miRNAs that regulate various physiological and pathological processes. The role of miR-125b in many types of cancer has been well established, and so here we review the current knowledge of how miR-125b is deregulated in different types of cancer; its oncogenic and/or tumour-suppressive roles in tumourigenesis and cancer progression; and its regulation with regard to treatment response, all of which are underlined in multiple studies. The emerging information that elucidates the essential functions of miR-125b might help support its potentiality as a diagnostic and prognostic biomarker as well as an effective therapeutic tool against cancer.

Scratch2, a Snail Superfamily Member, Is Regulated by miR-125b

Scratch2 is a transcription factor expressed in a very restricted population of vertebrate embryonic neural cell precursors involved in their survival, differentiation, and migration. The mechanisms that control its expression remain unknown and could contribute towards our understanding of gene regulation during neural differentiation and evolution. Here we investigate the role of microRNAs (miRNAs) in the Scrt2 post-transcriptional regulatory mechanism. We identified binding sites for miR-125b and -200b in the Scrt2 3′UTR in silico. We confirmed the repressive-mediated activity of the Scrt2 3′UTR through electroporation of luciferase constructs into chick embryos. Further, both CRISPR/Cas9-mediated deletion of miR-125b/-200b responsive elements from chicken Scrt2 3′UTR and expression of miRNAs sponges increased Scrt2 expression field, suggesting a role for these miRNAs as post-transcriptional regulators of Scrt2. The biological effect of miR-125b titration was much more pronounced than that of miR-200b. Therefore, we propose that, after transcription, miR-125b fine-tunes the Scrt2 expression domain.

Curcumol enhances the anti-tumor effects of metformin via suppressing epithelial-mesenchymal transition in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a severe disease with a high mortality rate. Metformin has been found to possess anti-tumor properties. Curcumol, an active ingredient extracted from curcuma, exerts the protective effect in TNBC cells through inducing apoptosis. However, the effects of curcumol combined with metformin on the treatment of TNBC have yet to be fully established.

Methods

TNBC cells MDA-MB-231 and MDA-MB-468 cells were used in the study. TNBC cells were treated with curcumol and metformin alone or treated with curcumol combined with metformin. Cell viability was determined using Cell Counting Kit-8 (CCK-8) assay. Cell apoptosis was detected using terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. The levels of proteins were measured using Western blot. Wound healing assay and Transwell invasion assays were used to determine cell migration and invasion ability, respectively. A xenograft model was established to investigate the tumor growth ability. Immunohistochemistry was performed to determine the expression of Ki-67 and Vascular endothelial growth factor (VEGF).

Results

In the study, the administration of curcumol alone had no significant effects on the TNBC cells. However, the anti-proliferation, anti-metastasis, and anti-epithelial-mesenchymal transition (EMT) effects of metformin were enhanced by the addition of curcumol. Further, curcumol reversed TNBC cell proliferation, migration, invasion, and EMT induced by rucaparib, and enhanced the effect of metformin on rucaparib-induced TNBC cells. The combination of curcumol and metformin also suppressed tumor growth, EMT marker expression, and the activation of Wnt2/β-Catenin signaling during in vivo experiments.

Conclusions

The combination of curcumol and metformin enhances the anti-tumor effects of metformin on TNBC via inhibiting EMT. Curcumol combined with metformin may hold promise as a therapeutic strategy for TNBC.

MicroRNAs target the Wnt/β‑catenin signaling pathway to regulate epithelial‑mesenchymal transition in cancer (Review)

Epithelial‑mesenchymal transition (EMT), during which cancer cells lose the epithelial phenotype and gain the mesenchymal phenotype, has been verified to result in tumor migration and invasion. Numerous studies have shown that dysregulation of the Wnt/β‑catenin signaling pathway gives rise to EMT, which is characterized by nuclear translocation of β‑catenin and E‑cadherin suppression. Wnt/β‑catenin signaling was confirmed to be affected by microRNAs (miRNAs), several of which are down‑ or upregulated in metastatic cancer cells, indicating their complex roles in Wnt/β‑catenin signaling. In this review, we demonstrated the targets of various miRNAs in altering Wnt/β‑catenin signaling to promote or inhibit EMT, which may elucidate the underlying mechanism of EMT regulation by miRNAs and provide evidence for potential therapeutic targets in the treatment of invasive tumors.

Potential miRNAs for miRNA-Based Therapeutics in Breast Cancer

MicroRNAs (miRNAs) are small non-coding RNAs that can post-transcriptionally regulate the genes involved in critical cellular processes. The aberrant expressions of oncogenic or tumor suppressor miRNAs have been associated with cancer progression and malignancies. This resulted in the dysregulation of signaling pathways involved in cell proliferation, apoptosis and survival, metastasis, cancer recurrence and chemoresistance. In this review, we will first (i) provide an overview of the miRNA biogenesis pathways, and in vitro and in vivo models for research, (ii) summarize the most recent findings on the roles of microRNAs (miRNAs) that could potentially be used for miRNA-based therapy in the treatment of breast cancer and (iii) discuss the various therapeutic applications.

Role of regulatory miRNAs of the Wnt/ β-catenin signaling pathway in tumorigenesis of breast cancer

Breast cancer is the most commonly diagnosed malignancy in women worldwide. Recently, uncontrolled expression of microRNAs was detected in several human disorders like cardiovascular, neurological, intestinal and autoimmunity diseases. MicroRNAs (miRNAs) are now investigated as novel prognostic and diagnostic biomarkers for several solid tumors like breast, lung, and gastrointestinal cancers. Current data suggest that miRNAs are implicated in various oncogenic processes implicated in breast cancer carcinogenesis trough modulating canonical Wnt pathway. Aberrant activation of Wnt/b-catenin signaling was shown to be significantly associated with tumor progression and poor prognosis in patients with breast cancer. This review presents recent findings on the molecular mechanism of microRNAs in regulation of Wnt/β-catenin signaling involved in tumorigenesis of breast cancer.

MicroRNA-125b as a tumor suppressor by targeting MMP11 in breast cancer

Background

Breast cancer is a common type of tumor in women worldwide. MicroRNAs have been identified as regulators in many human cancers. The aim of this study was therefore to investigate the functional role of miR‐125b in regulating breast cancer progression.

Methods

We used the StarBase database to investigate the expression of miRNA‐125b in breast cancer and adjacent normal tissues. MMP11 3′‐UTR construct and luciferase reporter assays was performed for target genes. Cell proliferation was evaluated by CCK‐8 and colony formation assay. The migration and invasion were assessed by transwell assay.

Results

Luciferase reporter assays showed miRNA‐125b directly targeted MMP11. miRNA‐125b by transfection with its mimic in breast cancer cells significantly suppressed breast cancer cell proliferation and migration. Western blot revealed that overexpression of miRNA‐125b substantially reduced MMP11 protein expression. We used the UALCAN database to investigate the expression of MMP11 in human breast cancer and adjacent normal tissues. In addition, we found that miRNA‐125b spoiled MMP11 induced breast cancer cell proliferation and migration promotion effect.

Conclusions

miRNA‐125b mimic inhibited proliferation, migration, and invasion of breast cancer cells through targeting MMP11 protein.

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.

Inhibition of SMYD2 suppresses tumor progression by down-regulating microRNA-125b and attenuates multi-drug resistance in renal cell carcinoma

SMYD2 is a histone methyltransferase that has been reported to be an important epigenetic regulator. This study aims to investigate SMYD2 as a prognostic indicator of clear cell renal cell carcinoma (ccRCC) and explore its role in tumorigenesis and multi-drug resistance.

Methods: Tumor specimens, clinicopathologic information, and prognostic outcomes of 186 ccRCC patients from three hospitals in China were collected for SMYD2 immunohistochemistry staining, Kaplan-Meier analysis, and Cox proportional hazards-regression analysis. MicroRNA (miRNA)-microarray profiling identified differentially expressed miRNAs in renal cancer cells subjected to SMYD2 knockdown or treatment with the SMYD2 inhibitor AZ505. The effects of SMYD2 and candidate SMYD2-mediated miRNAs on renal cancer cell proliferation, migration, clonogenicity, and tumorigenicity were determined via cell-function assays and murine xenograft experiments. The half-inhibitory concentrations (IC₅₀) of five antineoplastic drugs (cisplatin, doxorubicin, fluorouracil, docetaxel, and sunitinib) in AZ505-treated and control cells were calculated, and the effects of SMYD2 inhibition on P-glycoprotein (P-gP) expression and multiple-drug resistance were verified.

Results: SMYD2 was overexpressed and acted as an oncogene in ccRCC. High SMYD2 expression correlated with a high TNM stage (P = 0.007) and early tumor relapse (P = 0.032). SMYD2 independently predicted a worse overall survival (P = 0.022) and disease-free survival (P = 0.048). AZ505 inhibited the binding of SMYD2 to the miR-125b promoter region (based on chromatin immunoprecipitation assays) and suppressed ccRCC cell migration and invasion by inhibiting the SMYD2/miR-125b/DKK3 pathway. SMYD2 and miR-125b inhibition acted synergistically with anticancer drugs via P-gP suppression in vitro and in vivo.

Conclusions: These findings suggested that SMYD2 plays an important role in ccRCC development and could be a potential biomarker for the treatment and prognosis of RCC.

NELFE promoted pancreatic cancer metastasis and the epithelial‑to‑mesenchymal transition by decreasing the stabilization of NDRG2 mRNA

Negative elongation factor E (NELFE) has been demonstrated to promote cancer progression as an RNA‑binding protein (RBP). However, the expression patterns, biological role and molecular mechanism of NELFE in pancreatic cancer (PC) remain largely unknown. The expression levels of NELFE in 120 pairs of PC tissues and adjacent non‑tumor clinical samples collected from patients with PC were examined via reverse transcription‑quantitative (RT‑q) PCR and immunohistochemistry. The mRNA expression levels of NELFE, N‑Myc downstream‑regulated gene 2 (NDRG2), c‑Myc, survivin and cyclin D1 were detected via RT‑qPCR. The protein expression levels of NELFE, NDRG2, total β‑catenin, nuclear β‑catenin, cytosolic β‑catenin, E‑cadherin, N‑cadherin and Vimentin were measured by western blotting. NELFE and NDRG2 were then knocked‑down by short hairpin (sh)RNA. PC cell proliferation was detected by MTT and colony formation assays. Invasion and migration were detected by transwell assays. The interaction between NELFE and NDRG2 was detected by luciferase reporter assays, mRNA decay assays and RNA immunoprecipitation. NELFE expression was increased in PC tissues compared with the paired non‑cancerous tissues. NELFE expression was upregulated in PC cells when compared with normal pancreatic cells (HPDE6‑C7). The present study revealed that knockdown of NELFE inhibited the proliferation, invasion and migration of PC cells. In addition, transfection of the sh‑NELFE vector inhibited the epithelial‑to‑mesenchymal transition in PC cells by suppressing the expression and nuclear accumulation of β‑catenin. Further mechanistic studies revealed that NELFE activates the Wnt/β‑catenin signaling pathway by decreasing the stabilization of NDRG2 mRNA in PC. To the best of our knowledge, these results revealed the promotional function of NELFE on PC tumorigenesis and metastasis for the first time, helping to provide a promising strategy for the treatment of patients with PC.