MicroRNA-124-3p.1 promotes cell proliferation through Axin1-dependent Wnt signaling pathway and predicts a poor prognosis of triple-negative breast cancer

Comprehensive analysis of circRNA-miRNA-mRNA regulatory network and novel potential biomarkers in eutopic endometrium of adenomyosis

Adenomyosis (ADS) is a common gynecological disorder, and its pathogenesis remains unclear. This study explores the functions of circRNAs in the eutopic endometrium of ADS and their diagnostic efficacy for ADS. High-throughput RNA sequencing was performed on 12 eutopic endometrial samples from ADS patients and 3 control endometrial samples. Additionally, circRNAs were analyzed in conjunction with clinical features. A competitive endogenous RNA network was established based on bioinformatics analysis, comprising 3 circRNAs, 1 miRNA, and 13 mRNAs. In the ADS group, the expression levels of hsa_circ_0008959 and SLC15A4 were significantly reduced, while hsa-miR-124-3p expression was increased. SLC15A4 was associated with cell proliferation and invasion. Decreased expression of hsa_circ_0008959 and SLC15A4, along with high VAS scores and elevated hsa-miR-124-3p levels, were identified as risk factors for ADS development. The combination of hsa_circ_0008959 and VAS scores demonstrated the highest diagnostic value for ADS.

The scaffold protein AXIN1: gene ontology, signal network, and physiological function

AXIN1, has been initially identified as a prominent antagonist within the WNT/β-catenin signaling pathway, and subsequently unveiled its integral involvement across a diverse spectrum of signaling cascades. These encompass the WNT/β-catenin, Hippo, TGFβ, AMPK, mTOR, MAPK, and antioxidant signaling pathways. The versatile engagement of AXIN1 underscores its pivotal role in the modulation of developmental biological signaling, maintenance of metabolic homeostasis, and coordination of cellular stress responses. The multifaceted functionalities of AXIN1 render it as a compelling candidate for targeted intervention in the realms of degenerative pathologies, systemic metabolic disorders, cancer therapeutics, and anti-aging strategies. This review provides an intricate exploration of the mechanisms governing mammalian AXIN1 gene expression and protein turnover since its initial discovery, while also elucidating its significance in the regulation of signaling pathways, tissue development, and carcinogenesis. Furthermore, we have introduced the innovative concept of the AXIN1-Associated Phosphokinase Complex (AAPC), where the scaffold protein AXIN1 assumes a pivotal role in orchestrating site-specific phosphorylation modifications through interactions with various phosphokinases and their respective substrates.

A novel cross-communication of HIF-1α and HIF-2α with Wnt signaling in TNBC and influence of hypoxic microenvironment in the formation of an organ-on-chip model of breast cancer

The microenvironment role is very important in cancer development. The epithelial-mesenchymal transition of the cancer cells depends upon specific signaling and microenvironmental conditions, such as hypoxic conditions. The crosstalk between hypoxia and Wnt signaling through some molecular mechanism in TNBC is related. Cross-communication between hypoxia and Wnt signaling in cancer cells is known, but the detailed mechanism in TNBC is unknown. This review includes the role of the hypoxia microenvironment in TNBC and the novel crosstalk of the Wnt signaling and hypoxia. When targeted, the new pathway and crosstalk link may be a solution for metastatic TNBC and chemoresistance. The microenvironment influences cancer's metastasis, which changes from person to person. Therefore, organ-on-a-chip is a very novel model to test the drugs clinically before going for human trials, focusing on personalized medications can be done. The effect of the hypoxia microenvironment on breast cancer stem cells is still unknown. Apart from all the published papers, this paper mainly focuses only on the hypoxic microenvironment and its association with the growth of TNBC. The medicines or small proteins, drugs, mimics, and inhibitors targeting wnt and hypoxia genes are consolidated in this review paper.

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.

Circ_0008784 activates Wnt/β-catenin pathway to affect the proliferation and apoptosis of triple-negative breast cancer cells

Triple-negative breast cancer (TNBC), as a subtype of breast tumors with aggressive nature, threatens the health of females across the globe. It's urgent to explore novel therapeutic targets for the improvement of TNBC treatments. Bioinformatics was used to identify circular RNA (circRNA) differentially expressed in TNBC tissues. The circular structure and expression in TNBC cells was subjected to analysis of quantitative polymerase chain reaction (qPCR) and PCR-agarose gel electrophoresis. Functional experiments and qPCR assays were carried out to probe the biological functions of circ_0008784 and microRNA-506-3p (miR-506-3p). It was verified by the assays that circ_0008784 propels proliferation and inhibit apoptosis of TNBC cells; and miR-506-3p was found to suppress proliferation and facilitate apoptosis of TNBC cells. TOP/FOP-Flash reporter, luciferase reporter, RNA-binding protein immunoprecipitation (RIP), RNA pulldown and rescue assays were implemented for exploring the underlying mechanisms of circ_0008784. It was found that circ_0008784 regulates Wnt/β-catenin signaling pathway, and augments TNBC cell progression via sponging miR-506-3p to modulate catenin beta 1 (CTNNB1). Circ_0008784 activates Wnt/β-catenin pathway to affect the proliferation and apoptosis of TNBC cells. Elucidating the mechanism of circ_0008784 underlying TNBC is of great significance to TNBC treatment.

High-Throughput Analysis Reveals miRNA Upregulating α-2,6-Sialic Acid through Direct miRNA-mRNA Interactions

Chemical biology has revealed the importance of sialic acids as a major signal in physiology and disease. The terminal modification α-2,6-sialic acid is controlled by the enzymes ST6GAL1 and ST6GAL2. Dysregulation of this glycan impacts immunological recognition and cancer development. microRNAs (miRNA, miR), noncoding RNAs that downregulate protein expression, are important regulators of glycosylation. Using our recently developed high-throughput fluorescence assay (miRFluR), we comprehensively mapped the miRNA regulatory landscape of α-2,6-sialyltransferases ST6GAL1 and ST6GAL2. We found, contrary to expectations, the majority of miRNAs upregulate ST6GAL1 and α-2,6-sialylation in a variety of cancer cells. In contrast, miRNAs that regulate ST6GAL2 were predominantly downregulatory. Mutational analysis identified direct binding sites in the 3'-untranslated region (UTR) responsible for upregulation, confirming it is a direct effect. The miRNA binding proteins AGO2 and FXR1 were required for upregulation. Our results upend common assumptions surrounding miRNA, arguing that upregulation by these noncoding RNA is common. Indeed, for some proteins, upregulation may be the dominant function of miRNA. Our work also suggests that upregulatory miRNAs enhance overexpression of ST6GAL1 and α-2,6-sialylation, providing another potential pathway to explain the dysregulation observed in cancer and other disease states.

Regulation of the Key Epithelial Cancer Suppressor miR-124 Function by Competing Endogenous RNAs

A decrease in the miR-124 expression was observed in various epithelial cancers. Like a classical suppressor, miR-124 can inhibit the translation of multiple oncogenic proteins. Epigenetic mechanisms play a significant role in the regulation of miR-124 expression and involve hypermethylation of the MIR-124-1/-2/-3 genes and the effects of long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs) according to the model of competing endogenous RNAs (ceRNAs). More than 40 interactomes (lncRNA/miR-124/mRNA) based on competition between lncRNAs and mRNAs for miR-124 binding have been identified in various epithelial cancers. LncRNAs MALAT1, NEAT1, HOXA11-AS, and XIST are the most represented in these axes. Fourteen axes (e.g., SND1-IT1/miR-124/COL4A1) are involved in EMT and/or metastasis. Moreover, eight axes (e.g., OIP5-AS1/miR-124-5p/IDH2) are involved in key pathways, such as Wnt/b-catenin, E2F1, TGF-β, SMAD, ERK/MAPK, HIF-1α, Notch, PI3K/Akt signaling, and cancer cell stemness. Additionally, 15 axes impaired patient survival and three axes reduced chemo- or radiosensitivity. To date, 14 cases of miR-124 regulation by circRNAs have been identified. Half of them involve circHIPK3, which belongs to the exonic ecircRNAs and stimulates cell proliferation, EMT, autophagy, angiogenesis, and multidrug resistance. Thus, miR-124 and its interacting partners may be considered promising targets for cancer therapy.

miR766-3p and miR124-3p Dictate Drug Resistance and Clinical Outcome in HNSCC

Head and neck squamous cell carcinoma (HNSCC) is a highly aggressive disease with poor prognosis, which is mainly due to drug resistance. The biology determining the response to chemo-radiotherapy in HNSCC is poorly understood. Using clinical samples, we found that miR124-3p and miR766-3p are overexpressed in chemo-radiotherapy-resistant (non-responder) HNSCC, as compared to responder tumors. Our study shows that inhibition of miR124-3p and miR766-3p enhances the sensitivity of HNSCC cell lines, CAL27 and FaDu, to 5-fluorouracil and cisplatin (FP) chemotherapy and radiotherapy. In contrast, overexpression of miR766-3p and miR124-3p confers a resistance phenotype in HNSCC cells. The upregulation of miR124-3p and miR766-3p is associated with increased HNSCC cell invasion and migration. In a xenograft mouse model, inhibition of miR124-3p and miR766-3p enhanced the efficacy of chemo-radiotherapy with reduced growth of resistant HNSCC. For the first time, we identified that miR124-3p and miR766-3p attenuate expression of CREBRF and NR3C2, respectively, in HNSCC, which promotes aggressive tumor behavior by inducing the signaling axes CREB3/ATG5 and β-catenin/c-Myc. Since miR124-3p and miR766-3p affect complementary pathways, combined inhibition of these two miRNAs shows an additive effect on sensitizing cancer cells to chemo-radiotherapy. In conclusion, our study demonstrated a novel miR124-3p- and miR766-3p-based biological mechanism governing treatment-resistant HNSCC, which can be targeted to improve clinical outcomes in HNSCC.

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.

MicroRNA miR-124-3p suppresses proliferation and epithelial-mesenchymal transition of hepatocellular carcinoma via ARRDC1 (arrestin domain containing 1)

Hepatocellular carcinoma (HCC) is responsible for high morbidity and mortality worldwide. Increasing evidence suggests that microRNAs intensively participate in HCC development and progression. In the current study, we aimed to explore the impact of miR-124-3p in the proliferation and epithelial-mesenchymal transition (EMT) of HCC. The RT-qPCR assay was employed to determine miR-124-3p expression in human HCC specimens and cell lines. Luciferase assay was used to validate the miR-124-3p target gene. Western Blot and RT-qPCR were performed to study the effects of miR-124-3p modulation on ARRDC1 (Arrestin Domain Containing 1) mRNA and protein expressions. MTT assay, wound healing assay, EdU assay, and Transwell assay were utilized to verify the impact of miR-144-3p modulation on HCC proliferation and EMT via ARRDC1. We found that MiR-124-3p expression downregulates in HCC. Overexpression of miR-124-3p reduced the HCC cell proliferation and EMT. Meanwhile, we determined that the expression of ARRDC1 is increased in HCC, and miR-124-3p directly binds the 3'UTR of ARRDC1 and inhibits its expression at mRNA and protein level, suggesting that miR-124-3p was capable of negatively modulating ARRDC1. Besides, cotransfection of ARRDC1-overexpression plasmid and miR-124-3p mimics increased the cell proliferation and EMT as compared to miR-124-3p mimics. Our study concluded that miR-124-3p directly binds the 3'UTR of ARRDC1 and exerts anti-tumorous effects by inhibiting the HCC proliferation and EMT. Therefore, miR-124-3p/ARRDC1 axis may serve as a novel therapeutic target to inhibit HCC growth and metastasis.

The Wnt/β-catenin pathway in breast cancer therapy: a pre-clinical perspective of its targeting for clinical translation

INTRODUCTION

Despite various treatments available, there is still a high mortality rate in breast cancer patients. Thus, there exists an unmet need for new therapeutic interventions. Studies show that the Wnt/β-catenin signaling pathway is involved in breast cancer metastasis because of its transcriptional control on epithelial to mesenchymal transition.

AREAS COVERED

This comprehensive review explores the Wnt signaling pathway as a potential target for treating breast cancer and other breast cancer subtypes. We discuss the Wnt signaling pathway, its role in breast cancer metastasis, and its effect on breast cancer stem cells. Further, endogenous agents that cause Wnt pathway inactivation are outlined. Finally, various natural and chemical compounds modulating the Wnt pathway used in pre-clinical or clinical trials for breast cancer treatment are discussed.

EXPERT OPINION

In vitro and in vivo studies indicate an immense potential of agents targeting the Wnt signaling pathway to prevent and manage breast cancer. Still, more clinical studies are required to support their use in humans. Apart from the agents already in clinical trials, several drug combinations discussed may be translated into clinical practice in a few years.

MicroRNAs sequencing of plasma exosomes derived from patients with atrial fibrillation: miR-124-3p promotes cardiac fibroblast activation and proliferation by regulating AXIN1

MicroRNAs (miRNAs) play an important role in the pathogenesis of atrial fibrillation (AF). Exosomal miRNAs may develop as promising biomarkers for AF. To explore significant exosomal miRNAs in AF, plasma exosomes were extracted from 3 patients with AF and 3 patients with sinus rhythm (SR), respectively. Differential expression of exosomal miRNAs were screened by high-throughput sequencing analysis and verified by qRT-PCR from 40 patients with AF and 40 patients with SR. The target genes prediction, biological function, and signaling pathways analysis were conducted by miRanda software, gene ontology (GO), and KEGG analysis. The results showed that there were 40 differently expressed exosomal miRNAs from AF patients compared with SR patients, of which 13 miRNAs were upregulated and 27 miRNAs were downregulated. qRT-PCR validation demonstrated that miR-124-3p, miR-378d, miR-2110, and miR-3180-3p were remarkably upregulated, while miR-223-5p, miR-574-3p, miR-125a-3p, and miR-1299 were downregulated. To explore the function of miR-124-3p associated with AF, plasma exosomes derived from AF patients were co-incubated with rat myocardial fibroblasts. The expression of miR-124-3p was upregulated in myocardial fibroblasts. The viability and proliferation of myocardial fibroblasts were elevated by transfecting with miR-124-3p overexpression plasmids using CCK8 and immunofluorescence-staining methods. AXIN1 was verified to be the target of miR-124-3p by luciferase assay in vitro. Expression of AXIN1 was reduced, while β-catenin, Collagen 1, and α-SMA were increased in myocardial fibroblasts with miR-124-3p overexpression. In conclusion, these findings suggested that circulating exosomal miRNAs may serve as novel biomarkers for AF, and miR-124-3p promotes fibroblast activation and proliferation through regulating WNT/β-catenin signaling pathway via AXIN1.

LLLI promotes BMSC proliferation through circRNA_0001052/miR-124-3p

Osteoporosis (OP) is a multifactorial bone disease that occurs worldwide. The treatment of OP is still unsatisfactory. Bone mesenchymal stem cell (BMSC) differentiation is a key process in OP pathogenesis. Low-level laser irradiation (LLLI) has been reported to regulate BMSC proliferation, but the role of circRNAs in the LLLI-based promotion of BMSC proliferation remains unclear. CircRNAs are essential molecular regulators that participate in numerous biological processes and have therapeutic potential. miR-124-3p is an essential microRNA (miRNA), and its expression changes are related to BMSC proliferation ability. In the present study, gain-loss function of experiments demonstrated that circRNA_0001052 could regulate the proliferation of BMSCs by acting as a miR-124-3p sponge through the Wnt4/β-catenin pathway. The results of this study strongly suggest that circRNA_0001052 plays an essential role in BMSC proliferation in response to LLLI treatment, which is a potential therapeutic manipulation with clinical applications.

The potential role of miR-124-3p in tumorigenesis and other related diseases

MicroRNAs (miRNAs) are a class of single-stranded noncoding and endogenous RNA molecules with a length of 18-25 nucleotides. Previous work has shown that miR-124-3p leads to malignant progression of cancer including cell apoptosis, migration, invasion, drug resistance, and also recovers neural function, affects adipogenic differentiation, facilitates wound healing through control of various target genes. miR-124-3p has been mainly previously characterized as a tumor suppressor regulating tumorigenesis and progression in several cancers, such as hepatocellular carcinoma (HCC), gastric cancer (GC), bladder cancer, ovarian cancer (OC), and leukemia, as a tumor promotor in breast cancer (BC), and it has been also widely studied in a variety of neurological diseases, like Parkinson's disease (PD), dementia and Alzheimer's disease (AD), and cardiovascular diseases, ulcerative colitis (UC), acute respiratory distress syndrome (ARDS). To lay the groundwork for future therapeutic strategies, in this review we mainly focus on the most recent years of literature on the functions of miR-124-3p in related major cancers, as well as its downstream target genes. Although current work as yet provides an incomplete picture, miR-124-3p is still worthy of more attention as a practical and effective clinical biomarker.

Astragaloside IV Improves Tibial Defect in Rats and Promotes Proliferation and Osteogenic Differentiation of hBMSCs through MiR-124-3p.1/STAT3 Axis

Astragaloside IV (AST-IV) facilitates the proliferation and migration of osteoblast-like cells. We sought to explore the effect and potential mechanism of AST-IV on regeneration of tibial defects. To reveal the effect of AST-IV on regeneration of tibial defects in rat, HE staining and microcomputed tomography (μCT) were performed on tibial bone. The binding relationship between miR-124-3p.1 and STAT3 was analyzed by TargetScan V7.2 and a dual-luciferase reporter assay. Human bone marrow mesenchymal stromal/stem cells (hBMSCs) were identified by morphological observation and flow-cytometric analysis. To reveal the effect and mechanism of AST-IV on phenotypes of hBMSCs, hBMSCs were treated with AST-IV, miR-124-3p.1 mimic, and pcDNA-STAT3, and cell viability, cell cycle, ALP activity, and calcium deposition of hBMSCs in vitro were determined by MTT, flow-cytometric analysis, ELISA, and Alizarin red staining, respectively. The expressions of osteoblast marker molecules (RUNX2, OCN, Smad4), miR-124-3p.1, and STAT3 were indicated by RT-qPCR and Western blot. AST-IV decreased miR-124-3p.1 expression, increased STAT3 expression in tibial bone defects, and promoted regeneration of tibial bone defects in a concentration-dependent manner. The hBMSCs appeared spindle-shaped and were positive for CD105, but negative for CD34. MiR-124-3p.1 negatively regulated STAT3 expression in hBMSCs under osteogenic conditions. AST-IV promoted viability, cell cycle, ALP activity, and osteogenic differentiation of hBMSCs along with increased expressions of osteoblast marker molecules, which was partially reversed by miR-124-3p.1 overexpression. However, the effect of miR-124-3p.1 overexpression on hBMSCs was also partially reversed by STAT3 overexpression. AST-IV improves tibial defects in rats and promotes proliferation and osteogenic differentiation of hBMSCs through the miR-124-3p.1/STAT3 axis.

Overexpression of miR-1225 promotes the progression of breast cancer, resulting in poor prognosis

Breast cancer is the most common cancer among women, with metastasis as the principal cause of mortality. MiR-1225 has been reported to play roles in the progression of various cancers, but its role in breast cancer was unclear. The expression of miR-1225 was investigated in breast cancer tissues and cells by quantitative real-time PCR. The role of miR-1225 in the cell process of OS was analyzed by CCK-8 assay and Transwell assay. The prognostic value of miR-1225 was evaluated by Kaplan-Meier survival curves and Cox regression analysis. miR-1225 was significantly upregulated in breast cancer tissues, which was associated with the TNM stage of breast cancer patients. The prognosis of patients with high miR-1225 expression was worse than that of patients with low miR-1225 expression, which indicated that miR-1225 acted as an independent factor for the prognosis of breast cancer. Additionally, the upregulation of miR-1225 promoted cell proliferation, migration, and invasion of breast cancer, which suggested miR-1225 might be involved in the progression of breast cancer. JAK1 was identified as the direct target of miR-1225, which was also involved in cell proliferation, migration, and invasion of breast cancer. The overexpression of miR-1225 in breast cancer indicates a poor prognosis of patients and promotes the progression of breast cancer by targeting JAK1. miR-1225 may be a biomarker and therapeutic target for the treatment of breast cancer.

Long non‑coding RNA TTN‑AS1 regulates the proliferation, invasion and migration of triple‑negative breast cancer by targeting miR‑211‑5p

Increasing evidence has demonstrated that long non-coding RNAs (lncRNAs) serve important roles in numerous malignancies, including triple-negative breast cancer (TNBC). The lncRNA titin-antisense RNA1 (TTN-AS1) has previously been reported to promote tumorigenesis in various types of cancer. The present study aimed to investigate the potential role of TTN-AS1 in breast cancer and the associated underlying mechanisms. Following prediction by Starbase and confirmation by dual-luciferase reporter assay, TINCR was demonstrated to be a target gene for microRNA (miR)-211-5p. The expression levels of TTN-AS1 and miR-211-5p, which was predicted to be targeted by TTN-AS1, in TNBC tissues and in the breast cancer cell lines MDA-MB-453 and MDA-MB-231 were measured using reverse transcription-quantitative PCR. Following TTN-AS1-knockdown, cell proliferation was measured using a Cell Counting Kit-8 assay and colony formation assay, whereas cell invasion and migration were measured using Transwell and wound healing assays, respectively. Luciferase reporter assay was performed to verify the potential interaction between TTN-AS1 and miR-211-5p. In addition, rescue assays were conducted to investigate the effects of TTN-AS1 and miR-211-5p on TNBC development. The results demonstrated that TTN-AS1 expression was significantly upregulated, whereas that of miR-211-5p was found to be downregulated in TNBC tissues and cell lines compared with the matched adjacent normal tissues and normal breast epithelial cell line MCF-10A, respectively. Furthermore, TTN-AS1-knockdown inhibited the proliferation and invasive and migratory abilities of MDA-MB-453 and MDA-MB-231 cells, which was reversed following co-transfection with the miR-211-5p inhibitor. The results from luciferase reporter assay confirmed that miR-211-5p was a direct target of TTN-AS1, suggesting that TTN-AS1 may bind directly to miR-211-5p to negatively regulate its expression. In conclusion, the findings from the present study demonstrated that TTN-AS1 regulated the proliferation and invasive and migratory abilities of TNBC by targeting miR-211-5p. This study may provide some insights into the regulatory mechanism of TNBC and help the development of novel therapeutic interventions for TNBC.

MicroRNA-124-3p.1 promotes cell proliferation through Axin1-dependent Wnt signaling pathway and predicts a poor prognosis of triple-negative breast cancer

Background

Triple‐negative breast cancer (TNBC) is one subtype of breast cancer, which is characterized by an aggressive disease. It is commonly accompanied with extremely poor prognosis because of no available molecularly targeted therapy. Thus, understanding the detailed molecular mechanisms of TNBC is urgently needed.

Methods

The levels of Axis inhibition protein 1 (Axin1), Cyclin D1, c‐Myc, and miR‐124‐3p.1 were measured by quantitative real‐time PCR (qRT‐PCR). Furthermore, the breast cancer cell proliferation was measured by CCK‐8 assay, colony formation assays, and EdU staining. Xenograft model was used to show the tumor genesis of breast cancer cells. The regulatory function of miR‐124‐3p.1 on Wnt/β‐catenin signaling activation through directly targeting Axin1 was proven using qRT‐PCR, Western blot analysis, and dual‐luciferase reporter assay. To further assess the clinical significance of miR‐124‐3p.1 in the prognosis of breast cancer patients, we performed Kaplan‐Meier survival analysis and log‐rank tests.

Results

miR‐124‐3p.1 expression was elevated in advanced TNBC patients, and high miR‐124‐3p.1 predicts poor overall survival in TNBC patients. Further data showed that miR‐124‐3p.1 downregulation diminished, while miR‐124‐3p.1 upregulation increased the growth of TNBC cells in vitro and in vivo. Finally, we proved that miR‐124‐3p.1 exerted its function via targeting tumor suppressor gene Axin1 and activating the Wnt signaling pathway.

Conclusion

In summary, all the results demonstrate that miR‐124‐3p.1 promotes TNBC cell growth by controlling Axin1, suggesting that targeting miR‐124‐3p.1 might offer an effective therapeutic strategy for TNBC in the future.