MicroRNA-301b promotes cell proliferation and apoptosis resistance in triple-negative breast cancer by targeting CYLD

Expression profile and functional analysis of miR-301b in patients with breast cancer: A bioinformatics, biochemical, and histopathological study

BACKGROUND

microRNAs (miRNAs) are crucial regulators of various biological processes and molecular functions. Aberrant miRNA expression has been linked in many studies to neoplastic transformation. Among these miRNAs, dysregulation of miR-301b-5p was associated with different types of cancer including breast cancer. Although many research works have investigated the function of miR-301b in carcinogenesis, few have examined its expression, biological, and clinical implications in breast cancer.

METHODS

we examined the expression levels of miR-301b-5p in human cancerous breast tissue compared to normal breast controls using different bioinformatic tools and RT-qPCR analyses.

RESULTS

we detected that miR-301b-5p was differentially expressed in cancerous breast tissue when compared to normal controls. MiR-301b-5p was detected to be upregulated in high-grade (Grade 3) and triple-negative breast cancers. A significant strong positive correlation was detected between miR-301b and Ki-67, the commonly used proliferative marker in breast cancer. Bioinformatics analyses using the KM plotter revealed that miR-301b has significant prognostic power in assessing the OS of patients with breast cancer. The study also identified many fundamental biological processes and regulatory pathways associated with the investigated miR-301b-related hub genes. Interestingly, the expression pattern and prognostic significance of PTEN, the top hub gene regulated by miR-301b, highlighted the prognostic significance of PTEN in breast cancer.

CONCLUSION

The current study findings suggest the potential use of miR-301b-5p as a possible diagnostic and prognostic biomarker in breast cancer. Moreover, this study emphasized the clinical and biological relevance of miR-301b-5p in breast cancer.

Role of miR-301b-3p/5p in breast cancer: A study based on the cancer GenomeAtlas program (TCGA) and bioinformatics analysis

Background

Breast cancer is one of the most common cancer type of women in the world. miR-301b-3p/5p were paired miRNAs derived from the same pre-miRNA, which may have different clinical roles in tumor and requires more exploration and research.

Methods

In order to investigate the differential expression, clinical significance, diagnostic and prognostic value of miR-301b-3p/5p and explore their function in breast cancer, we extracted information of miRNAs from TCGA data sets for clinical correlation analysis, and the potential function was explored by GO、KEGG enrichment and immunoinfiltration analysis.

Results

miR-301b-3p/5p were both highly expressed in breast cancer, there is a positive correlation between them. miR-301b-3p and miR-301b-5p have different clinical features. In breast cancer, miR-301b-3p can be used as a potential diagnostic marker while miR-301b-5p can be used as a prognostic molecule. GO, KEGG enrichment and immunoinfiltration analysis reveals that miR-301b-3p focuses on molecular functions, miR-301b-5p focuses on regulation of angiogenesis, and it is correlated with immune cells.

Conclusions

miR-301b-3p and miR-301b-5p are both tumor promoter in breast cancer, miR-301b-3p can be used as a potential diagnostic marker, while miR-301b-5p can be used as a prognostic molecule and an underlying therapy target. Although miR-301b-3p/5p is a pair of miRNAs from two arms of the same pre-miRNA, they may promote the progression of breast cancer together through different pathway.

Genomic Index of Sensitivity to Chemotherapy for Triple Negative Breast Cancer

OBJECTIVE

Patients with triple-negative breast cancer (TNBC) frequently develop resistance to chemotherapy. Studies have shown that microRNAs (miRNAs) are often aberrantly expressed in TNBC and are associated with drug resistance. However, a prognostic strategy that correlates miRNAs with chemotherapy resistance remains largely unknown.

METHODS

To identify breast cancer chemoresistance-associated miRNAs, the miRNA microarray dataset GSE71142 was downloaded from the Gene Expression Omnibus database. Differentially expressed miRNAs (DE-miRNAs) in chemoresistant groups were identified using the LIMMA package in R. Potential target genes were predicted using the miRTarBase 9. Functional and pathway enrichment analyses was done using WebGestalt. A protein-protein interaction network was visualized using Cytoscape software. The top six hub genes regulated by DE-miRNAs were identified using the random forest model. The chemotherapy resistance index (CRI) in TNBC was defined as sum of the median expression levels of the top six hub genes. The association of CRI with distant relapse risk was evaluated using point-biserial correlation coefficient in the validation cohorts of patients with TNBC. The correlation between CRI and cumulative hazard rate was estimated using the Cox model, and the predicted rate of distant relapse was obtained from the Breslow-type estimator of the survival function. All statistical computations were performed using Origin2019b.

RESULTS

A total of 12 DE-miRNAs were screened, including six upregulated and six downregulated miRNAs in chemoresistant breast cancer tissues compared with chemosensitive tissues. Based on fold changes, miR-214-3p, miR-4758-3p, miR-200c-3p, miR-4254, miR-140-3p, and miR-24-3p were the top six most upregulated miRNAs, whereas miR-142-5p, miR-146-5p, miR-1268b, miR-1275, miR-4447, and miR-4472 were the top six most downregulated miRNAs. The top three hub genes for upregulated miRNAs were RAC1, MYC, and CCND1 and for downregulated miRNAs were IL-6, SOCS1, and PDGFRA. CRI was significantly associated with the risk of distant relapse.

CONCLUSION

CRI predicted survival benefits with reduced hazard rate.

Regulation of Inflammasome by microRNAs in Triple-Negative Breast Cancer: New Opportunities for Therapy

During the past decade, researchers have investigated the molecular mechanisms of breast cancer initiation and progression, especially triple-negative breast cancer (TNBC), in order to identify specific biomarkers that could serve as feasible targets for innovative therapeutic strategies development. TNBC is characterized by a dynamic and aggressive nature, due to the absence of estrogen, progesterone and human epidermal growth factor 2 receptors. TNBC progression is associated with the dysregulation of nucleotide-binding oligomerization domain-like receptor and pyrin domain-containing protein 3 (NLRP3) inflammasome, followed by the release of pro-inflammatory cytokines and caspase-1 dependent cell death, termed pyroptosis. The heterogeneity of the breast tumor microenvironment triggers the interest of non-coding RNAs' involvement in NLRP3 inflammasome assembly, TNBC progression and metastasis. Non-coding RNAs are paramount regulators of carcinogenesis and inflammasome pathways, which could help in the development of efficient treatments. This review aims to highlight the contribution of non-coding RNAs that support inflammasome activation and TNBC progression, pointing up their potential for clinical applications as biomarkers for diagnosis and therapy.

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.

Relative refractoriness of breast cancer cells to tumour necrosis factor-α induced necroptosis

Necroptosis, a recently identified programmed cell death pathway, has attracted attention as an alternative route to target apoptosis-resistant cancer cells. The status of the necroptosis pathway in different subtypes of breast cancer has not been well explored. Stimulating the cells by TNF-α can trigger cell survival or death depending on the combination of downstream players involved. In this work, we attempted to induce necroptosis in them using a combination of TNF-α and Z-VAD-FMK with and without chemotherapy. Cell viability, apoptosis, and necroptosis were assessed using MTT and Annexin-V/PI assays, respectively. Gene and protein expression was analysed by qPCR and immunophenotyping. Both the cell lines were resistant to induction of cell death by necroptosis. There was no enhancement in cell death when chemotherapeutic drugs were combined with necroptosis induction. Expression studies showed reduced translational expression of key necroptosis molecules like RIP kinases and MLKL in breast cancer cells compared to positive control cell line L929. Also, cell survival molecules were expressed more in MDA-MB-231 in contrast to death pathway molecules which were expressed more in T47D cells. In this work, the two breast cancer cell lines were observed to be resistant to TNF-α induced necroptosis with or without chemotherapy. Expression of key necroptosis players revealed relative insufficiency of the molecular machinery involved in the above pathway. In our opinion this may be the cause for resistance to necroptosis and novel strategies to upregulate these molecules need to be developed to sensitize the breast cancer cells towards cell death by necroptosis.

The correlation of leukocyte-specific protein 1 (LSP1) rs3817198(T>C) polymorphism with breast cancer: A meta-analysis

BACKGROUND

Multiple studies have investigated the correlation of single nucleotide polymorphisms (SNPs) in leukocyte-specific protein 1 (LSP1) with susceptibility to breast cancer (BC) and have yielded inconsistent conclusions, particularly rs3817198(T > C). Consequently, we performed a meta-analysis to estimate this relationship more comprehensively.

METHODS

Four databases were utilized to locate eligible publications: PubMed, Embase, Web of Science, and China National Knowledge Infrastructure. This meta-analysis included 14 studies, including 22 reports of 33194 cases and 36661 controls. The relationship of rs3817198 polymorphism with breast cancer was estimated using odds ratios (ORs) with 95% confidence intervals (CIs). The LSP1 co-expression network was constructed by STRING, and Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses were performed using DAVIDE. Download TCGA breast cancer mRNA-seq data and analyze the relationship between LSP1 expression and breast cancer chemotherapy sensitivity.

RESULTS

The results indicated that rs3817198(T > C) was positively correlated to with breast malignancy (dominant model: OR = 1.11, 95%CI = 1.06-1.17; recessive model: OR = 1.10, 95%CI = 1.04-1.15; heterozygous model: OR = 1.09, 95%CI = 1.04-1.15; homozygous model: OR = 1.18, 95%CI = 1.09-1.28; additive model: OR = 1.09, 95%CI = 1.05-1.13), among Caucasians and Asians. However, rs3817198(T > C) may reduce the risk of breast carcinoma in Africans. Rs3817198(T > C) might result in breast carcinoma in individuals with BRCA1 and BRCA2 variants and can contribute to estrogen receptor (ER)-positive breast carcinoma. The expression of LSP1 was inversely correlated with the IC50 of doxorubicin (P = 8.91e-15, Cor = -0.23), 5-fluorouracil (P = 1.18e-22, Cor = -0.29), and cisplatin (P = 1.35e-42, Cor = -0.40).

CONCLUSION

Our study identified that LSP1 rs3817198 polymorphism might result in breast malignancy, particularly among Caucasians and Asians, but lower breast cancer susceptibility in African populations. The expression of LSP1 was negatively correlated with the IC50 of doxorubicin, 5-fluorouracil, and cisplatin.

Noncoding RNAs in triple negative breast cancer: Mechanisms for chemoresistance

Triple-negative breast cancer (TNBC) is the most aggressive subtype among breast cancers with high recurrence and this condition is partly due to chemoresistance. Therefore, fully understanding the mechanism of TNBC-resistance is the key to overcoming chemoresistance, which will be an effective strategy for TNBC therapy. Various potential mechanisms involved in the chemoresistance of TNBC have been investigated and indicated that noncoding RNAs (ncRNAs) especially microRNAs (miRNAs), long noncoding RNAs (lncRNAs) and circular RNAs (circRNAs) take part in most TNBC resistance. The ncRNA-induced chemoresistance process is involved in the alteration of many activities. here, we mainly summarize the mechanisms of ncRNAs in the chemoresistance of TNBC and discuss the potential clinical application of ncRNAs in the treatment of TNBC, indicating that targeting ncRNAs might be a promising strategy for resensitization to chemotherapies.

Diagnostic and Prognostic Significance of serum miR-18a-5p in Patients with Atherosclerosis

Atherosclerosis (AS) is a common vascular disease with great harm. The current study examined the expression pattern of miR-18a-5p in AS patients, and explored its clinical values. 110 AS patients and 68 healthy controls were collected clinically, and the expression pattern of miR-18a-5p in the serum of AS patients was detected using qRT-PCR. All AS patients were followed up for five years to record the adverse cardiovascular events. ROC and Kaplan-Meier (K-M) curve were plotted to assess the diagnostic ability. The multiple Cox regression analysis was performed for independent influencing factors analysis. MiR-18a-5p was at high expression in AS patients, and showed positive correlation with the CIMT value (r = 0.789, P < .001). ROC curve suggested the high diagnostic value of serum miR-18a-5p for AS, with the AUC of 0.894. The diagnostic specificity and sensitivity were 86.8% and 79.1%, respectively. K-M plot demonstrated that cases with high miR-18a-5p levels were more likely to suffer from cardiovascular events, and it is an independent influence factor for the poor clinical outcome. Serum miR-18a-5p serves as a promising biomarker for AS diagnosis, and is related to the occurrence of adverse cardiovascular events.

Diallyl disulfide and diallyl trisulfide in garlic as novel therapeutic agents to overcome drug resistance in breast cancer

Breast cancer is one of the leading causes of cancer-related deaths in women worldwide. It is a cancer that originates from the mammary ducts and involves mutations in multiple genes. Recently, the treatment of breast cancer has become increasingly challenging owing to the increase in tumor heterogeneity and aggressiveness, which gives rise to therapeutic resistance. Epidemiological, population-based, and hospital-based case-control studies have demonstrated an association between high intake of certain Allium vegetables and a reduced risk in the development of breast cancer. Diallyl disulfide (DADS) and diallyl trisulfide (DATS) are the main allyl sulfur compounds present in garlic, and are known to exhibit anticancer activity as they interfere with breast cancer cell proliferation, tumor metastasis, and angiogenesis. The present review highlights multidrug resistance mechanisms and their signaling pathways in breast cancer. This review discusses the potential anticancer activities of DADS and DATS, with emphasis on drug resistance in triple-negative breast cancer (TNBC). Understanding the anticancer activities of DADS and DATS provides insights into their potential in targeting drug resistance mechanisms of TNBC, especially in clinical studies.

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The review describes the causes of drug resistance in TNBC.

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The effects of DADS and DATS on drug resistance mechanisms in TNBC are presented.

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The impacts of DADS and DATS on metastasis of TNBC are discussed.

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Antitumor immune activities of DADS and DATS against TNBC are illustrated.

Roles and Mechanisms of Deubiquitinases (DUBs) in Breast Cancer Progression and Targeted Drug Discovery

Deubiquitinase (DUB) is an essential component in the ubiquitin—proteasome system (UPS) by removing ubiquitin chains from substrates, thus modulating the expression, activity, and localization of many proteins that contribute to tumor development and progression. DUBs have emerged as promising prognostic indicators and drug targets. DUBs have shown significant roles in regulating breast cancer growth, metastasis, resistance to current therapies, and several canonical oncogenic signaling pathways. In addition, specific DUB inhibitors have been identified and are expected to benefit breast cancer patients in the future. Here, we review current knowledge about the effects and molecular mechanisms of DUBs in breast cancer, providing novel insight into treatments of breast cancer-targeting DUBs.

MicroRNA-370-3p shuttled by breast cancer cell-derived extracellular vesicles induces fibroblast activation through the CYLD/Nf-κB axis to promote breast cancer progression

Breast cancer is a malignancy arising in the mammary epithelial tissues. Recent studies have indicated the abundance of microRNAs (miRNAs) in extracellular vesicles (EVs), and their interactions have been illustrated to exert crucial roles in the cell-to-cell communication. The present study focused on investigating whether EV-delivered miR-370-3p affects breast cancer. Initially, the miR-370-3p expression pattern was examined in the cancer-associated fibroblasts (CAFs), normal fibroblasts (NFs), and cancerous cells-derived EVs. The relation of miR-370-3p to CYLD was assessed using luciferase activity assay. Afterwards, based on ectopic expression and depletion experiments in the MCF-7 breast cancer cells, we evaluated stemness, migration, invasion, and sphere formation ability, and EMT, accompanied with measurement on the expression patterns of pro-inflammatory factors and nuclear factor-kappa B (NF-κB) signaling-related genes. Finally, tumorigenesis and proliferation were analyzed in vivo using a nude mouse xenograft model. The in vitro experiments revealed that breast cancer cell-derived EVs promoted NF activation, while activated fibroblasts contributed to enhanced stemness, migration, invasion, as well as EMT of cancerous cells. In addition, EVs could transfer miR-370-3p from breast cancer cells to NFs, and EV-encapsulated miR-370-3p was also found to facilitate fibroblast activation. Mechanistically, EV-encapsulated miR-370-3p downregulated the expression of CYLD through binding to its 3'UTR and activated the NF-κB signaling pathway, thereby promoting the cellular functions in vitro and in vivo in breast cancer. Taken together, EVs secreted by breast cancer cells could carry miR-370-3p to aggravate breast cancer through downregulating CYLD expression and activating the NF-κB signaling pathway.

Breast Cancer Response to Therapy: Can microRNAs Lead the Way?

Breast cancer (BC) is a leading cause of death among women with malignant diseases. The selection of adequate therapies for highly invasive and metastatic BCs still represents a major challenge. Novel combinatorial therapeutic approaches are urgently required to enhance the efficiency of BC treatment. Recently, microRNAs (miRNAs) emerged as key regulators of the complex mechanisms that govern BC therapeutic resistance and susceptibility. In the present review we aim to critically examine how miRNAs influence BC response to therapies, or how to use miRNAs as a basis for new therapeutic approaches. We summarized recent findings in this rapidly evolving field, emphasizing the challenges still ahead for the successful implementation of miRNAs into BC treatment while providing insights for future BC management.The goal of this review was to propose miRNAs, that might simultaneously improve the efficacy of all four therapies that are the backbone of current BC management (radio-, chemo-, targeted, and hormone therapy). Among the described miRNAs, miR-21 and miR-16 emerged as the most promising, closely followed by miR-205, miR-451, miR-182, and miRNAs from the let-7 family. miR-21 inhibition might be the best choice for future improvement of invasive BC treatment.New therapeutic strategies of miRNA-based agents alongside current standard treatment modalities could greatly benefit BC patients. This review represents a guideline on how to navigate this elaborate puzzle.

Down-regulation of cylindromatosis protein phosphorylation by BTK inhibitor promotes apoptosis of non-GCB-diffuse large B-cell lymphoma

BACKGROUND

Non-germinal center B-cell-like diffuse large B-cell lymphoma (non-GCB-DLBCL) has worse clinical outcome than GCB-DLBCL, and some relapsed/refractory non-GCB-DLBCL (R/R non-GCB-DLBCL) are even resistant to CD20 monoclonal antibody (rituximab). Bruton's tyrosine kinase inhibitors (BTKis) are new drugs for B-cell lymphoma. BTKis can promote apoptosis of DLBCL by inactivating nuclear transcription factor κB (NFκB) signaling pathway. Cylindromatosis (CYLD) is a tumor suppressor and ubiquitinase. CYLD can inactivate NFκB signaling pathway through ubiquitination and regulate the apoptosis of hematological tumors. The ubiquitination of CYLD can be regulated by phosphorylation, suggesting that the regulation of CYLD phosphorylation can be a potential mechanism to promote the apoptosis of hematological tumors. Therefore, we hypothesized that BTKis could promote the apoptosis of non-GCB-DLBCL by regulating the phosphorylation of CYLD, especially in rituximab resistant cases, and we proved this hypothesis through both in vivo and in vitro experiments.

METHODS

The baseline expression levels of CYLD phosphorylation in non-GCB-DLBCL patients and cell lines were detected by Western Blotting. The non-GCB-DLBCL cell lines were treated with BTKis, and apoptosis induced by BTKis treatment was detected by Western blotting, cell viability assay and Annexin V assay. To verify whether the effect of BTKis on apoptosis in non-GCN-DLBCL cells is CYLD dependent, the expression of CYLD was knocked down by lentiviral shRNAs. To verify the effect of BTKis on the phosphorylation of CYLD and the apoptosis in vivo and in rituximab resistant non-GCB-DLBCL, the xeograft model and rituximab resistant non-GCB-DLBCL cells were generated by tumor cell inoculation and escalation of drug concentrations, respectively.

RESULTS

BTKis induced apoptosis by down-regulating CYLD phosphorylationin in non GCB-DLBCL, xenograft mouse model, and rituximab-resistant cells, and this effect could be enhanced by rituximab. Knocking-down CYLD reversed apoptosis which was induced by BTKis. BTKis induced CYLD-dependent apoptosis in non-GCB-DLBCL including in rituximab-resistant cells.

CONCLUSIONS

The present results indicated that CYLD phosphorylation is a potential clinical therapeutic target for non-GCB-DLBCL, especially for rituximab-resistant relapsed/refractory cases.

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.

Oncogenic microRNA-301b regulates tumor repressor dystrobrevin alpha to facilitate cell growth, invasion and migration in esophageal cancer

BACKGROUND

Esophageal cancer (EC) ranks the eighth in morbidity and the sixth in mortality around the whole world, which is an aggressive malignancy. To authenticate potential therapeutic targets for EC is therefore imperative. Although miR-301b might display changed expression in esophageal adenocarcinoma by utilizing Taqman miRNA profiling analysis, much less is known about the impact of miR-301b in EC.

METHODS AND RESULTS

By analyzing the data of 187 cancer tissues and 13 normal samples from TCGA database, we discovered that miR-301b was highly expressed in EC tissues. Then, RT-qPCR determined that miR-301b was up-regulated in EC cell lines (ECA109, JAR, TE-1 and OE33). Besides, miR-301b expression level was higher in ESCC cell line-TE-1 cells and lower in ESCC cell line-ECA109 cells compared to other EC cell lines. Hence, ECA109 cell line was used to up-regulate miR-301b expression while TE-1 cell line was applied to down-regulate miR-301b expression in the subsequent experiments. Additionally, OE33, as an ECA cell line, was applied to upregulate miR-301b expression to reflect the influence of miR-301b overexpression on EC progression. More interestingly, miR-301b appeared to act as a promoting effect on the proliferation of EC cells, which was tested by CCK8. Dystrobrevin alpha (DTNA) was a targeting gene of miR-301b, which was predicted by the websites of miRanda, miRWalk and TargetScan. Additionally, DTNA was low expressed in EC tissues and was an independent predictor of EC. Meanwhile, the low expression of DTNA was related to worse overall survival in EC patients. The Pearson correlation coefficient analyzed that DTNA expression was negatively correlated with miR-301b. Furthermore, RT-qPCR and western blotting assays ulteriorly indicated that DTNA was negatively modulated by miR-301b. The facilitating impact of miR-301b re-expression on ECA109 and OE33 cell growth, invasion and migration was receded by DTNA over-expression, whilst the repressive effect of miR-301b ablation on TE-1 cell growth, invasion and migration was inversed by DTNA silencing. Overexpression of miR-301b accelerated EC cell growth, migration and invasion through targeting DTNA.

CONCLUSIONS

Above all, we concluded that miR-301b was concerned with the progression of EC via regulating DTNA, suggesting that miR-301b and its target gene, DTNA, might serve as predictive biomarkers for EC therapy.

Progress of non-coding RNAs in triple-negative breast cancer

Non-coding RNAs (ncRNAs) include miRNA, lncRNA, and circRNA. NcRNAs are involved in multiple biological processes, including chromatin remodeling, signal transduction, post-transcriptional modification, cell autophagy, carbohydrate metabolism, and cell cycle regulation. Triple negative breast cancer (TNBC) is notorious for high invasiveness and metastasis, poor prognosis, and high mortality, and it is the most malignant breast cancer, while the effective targets for TNBC treatment are still lacking. NcRNAs act as oncogenes or suppressor genes, as well as promote or inhibit the occurrence and development of TNBC. Here, we reviewed some important miRNAs, lncRNAs, circRNAs, their target(s) and molecular mechanisms in TNBC. It is benefited to understand the occurrence and development of TNBC, further some ncRNAs might be potential targets for TNBC treatment.

miR-301b and NR3C2 co-regulate cells malignant properties and have the potential to be independent prognostic factors in breast cancer

This study intends to address the function of miR-301b/nuclear receptor subfamily 3 group C member 2 (NR3C2) in breast cancer. The Cancer Genome Atlas database was processed to investigate the expression of miR-301b/NR3C2 in breast cancer samples, as well as the relationship between their expression and the prognosis of the patients. Cox regression analysis was performed to determine whether miR-301b/NR3C2 was an independent predictor of the patient's prognosis. Associations between miR-301b and NR3C2 were analyzed by prediction website, dual-luciferase assay, and Pearson correlation coefficient. Quantitative polymerase chain reaction and Western blot analyses were implemented to detect gene expression. The relevant biological characteristics of MCF7 and BCAP-37 cells were tested by cell counting kit-8, colony formation, and transwell assays. Lower expression of NR3C2, which was closely related to the bad prognosis of breast cancer patients, was presented in breast cancer samples and can be used as an independent predictor. miR-301b, as an upstream regulator of NR3C2, was highly expressed in breast cancer samples and can be used as an independent predictor as well. Notably, a higher level of miR-301b and lower level of NR3C2 were related to the reduced overall survival in patients with breast cancer. The proliferative and migratory behaviors of cells were elevated or blocked after overexpression of miR-301b or NR3C2, respectively. However, the above situation was attenuated after together upregulation of miR-301b and NR3C2. The present data afforded evidence that miR-301b may be a tumor-promoting miRNA in breast cancer, and that miR-301b/NR3C2 axis mediated tumor development from cell proliferation and migration.

Clinicopathological Significances of Cancer Stem Cell-Associated HHEX Expression in Breast Cancer

Aberrant expression of the transcription factor hematopoietic ally expressed homeobox/proline-rich homeodomain (HHEX/PRH) is implicated in numerous cancers. However, the association of HHEX with breast cancer (BC) remains unclear. In this study, HHEX mRNA and protein expression were analyzed using the Oncomine, UALCAN, GEPIA, TCGAportal, and HPA databases. We evaluated the effect of HHEX on clinicopathological parameters using Kaplan–Meier plotter, OncoLnc, TCGAportal, PROGgeneV2, and BC-GenExMiner. Western blotting was performed to compare the level of HHEX in breast samples of Tientsin Albino 2 mice, human breast precancerous lesions, benign breast tumors, and BC. The correlation between HHEX and cancer stem cells was investigated using the GEO (GSE52327 and GSE94865) and GEPIA datasets. Networks between HHEX and survival-related gene marker sets and microRNAs were analyzed using GEPIA, StarBase, and Cytoscape. Results of this study showed that HHEX expression in BC was significantly lower than those in breast precancerous lesions and benign breast tumors at both mRNA and protein levels. BC patients with lower HHEX expression had significantly worse overall survival and disease-free survival. Moreover, HHEX significantly affected the clinicopathology of BC. Specifically, low HHEX expression was correlated with the following groups of patients: age ≤51 years, ER-negative or PR-negative patients, HER-2 positive, triple-negative breast cancer, and basal-like BC. Immunohistochemical analysis of the breast samples showed significant differences of HHEX staining index (P < 0.001) among the three groups. To further investigate the mechanism, we determined the intersection of differentially expressed genes related to BC stem cells and those genes after HHEX expression was altered. This led to the identification of four potentially regulated genes-CXL12, BLNK, PAG1, and LPXN. Using StarBase and km-plotter, the negative regulation of HHEX expression and survival trends, including miR-130b, miR-30e, and miR-301b were joined into miRNA-HHEX-mRNA potential regulatory network. The abilities of proliferation, migration and invasion increased in MDA-MB-231 and BT-549 breast cancer cell lines after HHEX down expression and decreased after HHEX overexpression compared them in the control cells. In conclusion, these data suggest that HHEX expression is downregulated in BC and HHEX may regulate the development of BC through the stem cell-related genes.

Inhibiting microRNA-301b suppresses cell growth and targets RNF38 in cervical carcinoma

It has been reported microRNA-301b (miR-301b) was involved in the tumorigenesis of some cancers, but it has not been investigated in cervical carcinoma yet. In this study, miR-301b was found significantly upregulated in cervical carcinoma, and patients with high miR-301b expression had a shorter overall survival. When miR-301b was knocked down in cervical carcinoma cells, the cell growth could be significantly abolished. Our further studies showed miR-301b targeted RNF38, and inhibited its expression in cervical carcinoma cells. Moreover, RNF38 was found downregulated in cervical carcinoma, and miR-301b expression in cervical tissues was found negatively correlated with RNF38 expression. In addition, overexpression of RNF38 significantly inhibited cervical carcinoma cell growth, but overexpression of miR-301b suppressed RNF38-induced cell growth inhibition in cervical carcinoma. Collectively, this study suggested miR-301b could be a novel target for cervical carcinoma treatment.

CYLD Promotes Apoptosis of Nasopharyngeal Carcinoma Cells by Regulating NDRG1

Purpose

Nasopharyngeal carcinoma (NPC) is among the most common malignancies derived from the epithelium of the nasopharynx. To date, the regulatory networks involved in NPC have not been fully identified. Previous studies revealed multiple loss-of-function mutations in NPC and specifically in cylindromatosis lysine 63 deubiquitinase (CYLD); however, the exact role of CYLD in NPC progression and its potential mechanism remains unclear.

Methods

We performed immunohistochemical (IHC) staining and real-time quantitative polymerase chain reaction (qPCR) to measure CYLD expression in NPC tissues, and Western blot was conducted to determine CYLD levels in NPC cell lines. Cell proliferation was detected by CCK8 assay and colony formation analysis, and apoptosis was determined by Annexin V/propidium iodide staining. Potential targets of CYLD were verified by co-immunoprecipitation and mass spectrometry. Xenograft assay was conducted to confirm the role of CYLD in vivo.

Results

We found that CYLD levels were significantly decreased in both NPC tissues and cell lines, and that CYLD overexpression inhibited NPC cell proliferation and promoted apoptosis. Additionally, we revealed that CYLD bound and upregulated N-Myc downstream regulated 1 (NDRG1), and that silencing NDRG1 abolished the tumor-suppressor effect of CYLD on NPC cells. Furthermore, CYLD suppressed tumor growth in xenograft mice models.

Conclusion

These results suggest CYLD as a tumor suppressor, potential biomarker for diagnosing NPC, and therapeutic target.

The Tumor Suppressor CYLD Inhibits Mammary Epithelial to Mesenchymal Transition by the Coordinated Inhibition of YAP/TAZ and TGF Signaling

Downregulation of the cylindromatosis (CYLD) tumor suppressor has been associated with breast cancer development and progression. Here, we report a critical role for CYLD in maintaining the phenotype of mammary epithelial cells in vitro and in vivo. CYLD downregulation or inactivation induced an epithelial to mesenchymal transition of mammary epithelial cells that was dependent on the concomitant activation of the transcription factors Yes-associated protein (YAP)/transcriptional coactivator with PDZ-binding motif (TAZ) and transforming growth factor beta (TGF)signaling. CYLD inactivation enhanced the nuclear localization of YAP/TAZ and the phosphorylation of Small Mothers Against Decapentaplegic (SMAD)2/3 proteins in confluent cell culture conditions. Consistent with these findings were the hyperplastic alterations of CYLD-deficient mouse mammary epithelia, which were associated with enhanced nuclear expression of the YAP/TAZ transcription factors. Furthermore, in human breast cancer samples, downregulation of CYLD expression correlates with enhanced YAP/TAZ-regulated target gene expression. Our results identify CYLD as a critical regulator of a signaling node that prevents the coordinated activation of YAP/TAZ and the TGF pathway in mammary epithelial cells, in order to maintain their phenotypic identity and homeostasis. Consequently, they provide a novel conceptual framework that supports and explains a causal implication of deficient CYLD expression in aggressive human breast cancers.

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.

USP47 Promotes Tumorigenesis by Negative Regulation of p53 through Deubiquitinating Ribosomal Protein S2

p53 is activated in response to cellular stresses such as DNA damage, oxidative stress, and especially ribosomal stress. Although the regulations of p53 by E3 ligase and deubiquitinating enzymes (DUBs) have been described, the cellular roles of DUB associated with ribosomal stress have not been well studied. In this study, we report that Ubiquitin Specific Protease 47 (USP47) functions as an important regulator of p53. We show that ubiquitinated ribosomal protein S2 (RPS2) by Mouse double minute 2 homolog (MDM2) is deubiquitinated by USP47. USP47 inhibits the interaction between RPS2 and MDM2 thereby alleviating RPS2-mediated suppression of MDM2 under normal conditions. However, dissociation of USP47 leads to RPS2 binding to MDM2, which is required for the suppression of MDM2, consequently inducing up-regulation of the p53 level under ribosomal stress. Finally, we show that depletion of USP47 induces p53 and therefore inhibits cell proliferation, colony formation, and tumor progression in cancer cell lines and a mouse xenograft model. These findings suggest that USP47 could be a potential therapeutic target for cancer.

miR-208b-5p inhibits invasion of non-small cell lung cancer through the STAT3 pathway by targeting interleukin-9

Previous studies reported a dysregulation of micro (mi)R-208b-5p expression level in various types of human cancer; however, the role of miR-208-5p in non-small cell lung cancer (NSCLC) remains unclear. Therefore, the present study aimed to determine whether miR-208b-5p could regulate NSCLC progression. A total of 62 pairs of primary tumor and adjacent normal tissues were collected from patients with NSCLC. miR-208b-5p expression level was determined by reverse transcription-quantitative polymerase chain reaction. Furthermore, miR-208b-5p mimics was transfected into NSCLC A549 and H1299 cells in order to upregulate miR-208b-5p expression. Dual-luciferase reporter assay was utilized to investigate the associations between miR-208b-5p and IL9 mRNA. The results demonstrated that miR-208b-5p expression decreased in NSCLC tissues and cell lines. Furthermore, miR-208b-5p overexpression inhibited A549 and H1299 cell proliferation and invasiveness. miR-208b-5p was demonstrated to bind directly to the 3' untranslated region of interleukin-9 (IL-9) and therefore decreased its expression. In the NSCLC-derived cell lines, miR-208b-5p inactivated IL-9/signal transducer and activator of transcription 3 (STAT3) signaling pathway. Furthermore, enhanced IL-9 level decreased the miR-208b-5p-mediated suppression of epithelial-mesenchymal transition in NSCLC cells by inactivating the STAT3 signaling pathway. In conclusion, the findings from this study demonstrated that miR-208b-5p inhibited migration and invasion of NSCLC cells. The anti-tumor activity of miR-208b-5p may be mediated by IL-9 and STAT-3 pathway.

MicroRNA-449b-3p inhibits epithelial-mesenchymal transition by targeting IL-6 and through the JAK2/STAT3 signaling pathway in non-small cell lung cancer

MicroRNAs (miRs) have vital involvement in the advancement of non-small cell lung cancer (NSCLC); however, the methods of action of miR-449b-3p in the disease are yet to be examined. The present study revealed a distinct downregulation of miR-449b-3p in NSCLC tissue, which was related to the clinicopathological characteristics, and may serve as an independent marker for NSCLC prognosis. NSCLC cell epithelial-mesenchymal transition (EMT), metastasis and migration were distinctly controlled in vitro by miR-449b-3p, that was found to directly target interleukin (IL)-6. Additionally, increased IL-6 level could inhibit miR-449b-3p and suppress the effect of EMT in NSCLC cells by inactivating the Janus kinase 2 (JAK2)/STAT3 signaling pathway. In conclusion, the data from the present study demonstrated that IL-6 is targeted by miR-449b-3p, which affects the JAK2/STAT3 signaling pathway, impacting on the development of NSCLC.

miR-30a-3p inhibits the proliferation of liver cancer cells by targeting DNMT3a through the PI3K/AKT signaling pathway

MicroRNAs (miRNAs or miRs) are crucial for normal development and maintenance of homeostasis. Dysregulated miRNA expression contributes to numerous pathological conditions, including cancer tumorigenesis. However, a limited number of studies have examined the regulatory effects of miR-30a-3p in tumorigenesis. Therefore, the present study investigated the mechanistic process of tumorigenesis in liver cancer. The results revealed a high expression of DNA methyltransferase 3a (DNMT3a) and a low expression of miR-30a-3p in HepG2 cells compared with that in the L02 cell line. A luciferase reporter assay demonstrated that DNMT3a is a direct target of miR-30a-3p. In addition, DNMT3a overexpression significantly enhanced cell proliferation, which was reversed by a miR-30a-3p mimic. Similarly, the miR-30a-3p mimic blocked DNMT3a-triggered cell cycle processes and apoptosis by attenuating active p-AKT and p-PI3K in HepG2 cells. In summary, the results of the present study demonstrate that miR-30a-3p is essential for cell proliferation regulation via its association with AKT/PI3K signaling in liver cancer. These results provide insight into the molecular mechanism by which miR-30a-3p inhibits liver cancer cell proliferation and provides a foundation for its clinical development and application.

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.

MicroRNA-301b-3p accelerates the growth of gastric cancer cells by targeting zinc finger and BTB domain containing 4

MicroRNAs (miRNAs) have been found to be aberrantly expressed and exert essential roles in the tumorigenesis and progression of gastric cancer (GC). miR-301b-3p has been recognized as a cancer-related miRNA in lung cancer, bladder cancer and hepatocellular carcinoma. However, the function of miR-301b-3p in GC progression and its underlying mechanism have not been studied yet. In this study, we found that miR-301b-3p expression was up-regulated in GC tissues compared to adjacent noncancerous tissues. Furthermore, the elevated levels of miR-301b-3p were detected in GC cell lines (SGC-7901, AGS, MKN-45 and MGC-803) as compared with GES-1 cells. Interestingly, GC tissues from patients with tumor size ≥ 5 cm and advanced tumor stages showed obvious higher levels of miR-301b-3p compared to matched controls. Functionally, miR-301b-3p knockdown prominently inhibited cell proliferation, and induced cell cycle arrest at G1 phase and apoptosis in MGC-803 cells. Meanwhile, ectopic expression of miR-301b-3p conversely regulated these biological behaviors of MKN-45 cells. Next, we found that miR-301b-3p knockdown increased, whereas miR-301b-3p overexpression reduced the expression of zinc finger and BTB domain containing 4 (ZBTB4) in GC cells. Accordingly, luciferase reporter assay identified ZBTB4 as a direct target of miR-301b-3p. ZBTB4 overexpression markedly restrained the growth of MGC-803 cells. More importantly, ZBTB4 silencing partially reversed miR-301b-3p knockdown-induced tumor suppressive effects on MGC-803 cells. In conclusion, we firstly revealed that miR-301-3p was highly expressed in GC and contributed to tumor progression via attenuating ZBTB4, which might provide a novel molecular-targeted strategy for GC treatment.

Microtubule-associated tumor suppressors as prognostic biomarkers in breast cancer

PURPOSE

Breast cancer is the most common malignancy in women worldwide. Although important therapeutic progress was achieved over the past decade, this disease remains a public health problem. In light of precision medicine, the identification of new prognostic biomarkers in breast cancer is urgently needed to stratify populations of patients with poor clinical outcome who may benefit from new personalized therapies. The microtubule cytoskeleton plays a pivotal role in essential cellular functions and is an interesting target for cancer therapy. Microtubule assembly and dynamics are regulated by a wide range of microtubule-associated proteins (MAPs), some of which have oncogenic or tumor suppressor effects in breast cancer.

RESULTS

This review covers current knowledge on microtubule-associated tumor suppressors (MATS) in breast cancer and their potential value as prognostic biomarkers. We present recent studies showing that combinatorial expression of ATIP3 and EB1, two microtubule-associated biomarkers with tumor suppressor and oncogenic effects, respectively, improves breast cancer prognosis compared to each biomarker alone.

CONCLUSIONS

These findings are discussed regarding the increasing complexity of protein networks composed of MAPs that coordinate microtubule dynamics and functions. Further studies are warranted to evaluate the prognostic value of combined expression of different MATS and their interacting partners in breast cancer.

MicroRNAs and Epigenetics Strategies to Reverse Breast Cancer

Breast cancer is a sporadic disease with genetic and epigenetic components. Genomic instability in breast cancer leads to mutations, copy number variations, and genetic rearrangements, while epigenetic remodeling involves alteration by DNA methylation, histone modification and microRNAs (miRNAs) of gene expression profiles. The accrued scientific findings strongly suggest epigenetic dysregulation in breast cancer pathogenesis though genomic instability is central to breast cancer hallmarks. Being reversible and plastic, epigenetic processes appear more amenable toward therapeutic intervention than the more unidirectional genetic alterations. In this review, we discuss the epigenetic reprogramming associated with breast cancer such as shuffling of DNA methylation, histone acetylation, histone methylation, and miRNAs expression profiles. As part of this, we illustrate how epigenetic instability orchestrates the attainment of cancer hallmarks which stimulate the neoplastic transformation-tumorigenesis-malignancy cascades. As reversibility of epigenetic controls is a promising feature to optimize for devising novel therapeutic approaches, we also focus on the strategies for restoring the epistate that favor improved disease outcome and therapeutic intervention.

Mechanisms of Chemotherapy Resistance in Triple-Negative Breast Cancer-How We Can Rise to the Challenge

Triple-negative (TNBC) is the most lethal subtype of breast cancer owing to high heterogeneity, aggressive nature, and lack of treatment options. Chemotherapy remains the standard of care for TNBC treatment, but unfortunately, patients frequently develop resistance. Accordingly, in recent years, tremendous effort has been made into elucidating the mechanisms of TNBC chemoresistance with the goal of identifying new molecular targets. It has become evident that the development of TNBC chemoresistance is multifaceted and based on the elaborate interplay of the tumor microenvironment, drug efflux, cancer stem cells, and bulk tumor cells. Alterations of multiple signaling pathways govern these interactions. Moreover, TNBC's high heterogeneity, highlighted in the existence of several molecular signatures, presents a significant obstacle to successful treatment. In the present, in-depth review, we explore the contribution of key mechanisms to TNBC chemoresistance as well as emerging strategies to overcome them. We discuss novel anti-tumor agents that target the components of these mechanisms and pay special attention to their current clinical development while emphasizing the challenges still ahead of successful TNBC management. The evidence presented in this review outlines the role of crucial pathways in TNBC survival following chemotherapy treatment and highlights the importance of using combinatorial drug strategies and incorporating biomarkers in clinical studies.

MicroRNA-301b-3p contributes to tumour growth of human hepatocellular carcinoma by repressing vestigial like family member 4

MicroRNAs (miRNAs) are key regulators in the tumour growth and metastasis of human hepatocellular carcinoma (HCC). Increasing evidence suggests that miR-301b-3p functions as a driver in various types of human cancer. However, the expression pattern of miR-301b-3p and its functional role as well as underlying molecular mechanism in HCC remain poorly known. Our study found that miR-301b-3p expression was significantly up-regulated in HCC tissues compared to adjacent non-tumour tissues. Clinical association analysis revealed that the high level of miR-301b-3p closely correlated with large tumour size and advanced tumour-node-metastasis stages. Importantly, the high miR-301b-3p level predicted a prominent poorer overall survival of HCC patients. Knockdown of miR-301b-3p suppressed cell proliferation, led to cell cycle arrest at G2/M phase and induced apoptosis of Huh7 and Hep3B cells. Furthermore, miR-301b-3p knockdown suppressed tumour growth of HCC in mice. Mechanistically, miR-301b-3p directly bond to 3'UTR of vestigial like family member 4 (VGLL4) and negatively regulated its expression. The expression of VGLL4 mRNA was down-regulated and inversely correlated with miR-301b-3p level in HCC tissues. Notably, VGLL4 knockdown markedly repressed cell proliferation, resulted in G2/M phase arrest and promoted apoptosis of HCC cells. Accordingly, VGLL4 silencing rescued miR-301b-3p knockdown attenuated HCC cell proliferation, cell cycle progression and apoptosis resistance. Collectively, our results suggest that miR-301b-3p is highly expressed in HCC. miR-301b-3p facilitates cell proliferation, promotes cell cycle progression and inhibits apoptosis of HCC cells by repressing VGLL4.

SETDB1 regulates SMAD7 expression for breast cancer metastasis

Breast cancer (BRC) is the most invasive cancer in women. Although the survival rate of BRC is gradually increasing due to improved screening systems, development of novel therapeutic targets for inhibition of BRC proliferation, metastasis and recurrence have been constantly needed. Thus, in this study, we identified overexpression of SETDB1 (SET Domain Bifurcated 1), a histone methyltransferase, in RNA-seq data of BRC derived from TCGA portal. In Gene Ontology (GO) analysis, cell migration-related GO terms were enriched, and we confirmed down-regulation of cell migration/invasion and alteration of EMT/MET markers after knockdown of SETDB1. Moreover, gene network analysis showed that SMAD7 expression is regulated by SETDB1 levels, indicating that up-regulation of SMAD7 by SETDB1 knockdown inhibited BRC metastasis. Therefore, development of SETDB1 inhibitors and functional studies may help develop more effective clinical guidelines for BRC treatment.

MicroRNA-331-3p inhibits epithelial-mesenchymal transition by targeting ErbB2 and VAV2 through the Rac1/PAK1/β-catenin axis in non-small-cell lung cancer

MicroRNAs have been reported to play critical roles in the regulation of non-small-cell cancer (NSCLC) development, but the role of microRNA (miR)-331-3p in NSCLC is still unclear. In this study, the expression levels of miR-331-3p in NSCLC tumor tissues and adjacent normal tissues were examined by quantitative RT-PCR, and the relationship between miR-331-3p expression and patient clinicopathological characteristics was analyzed. The effects of miR-331-3p on epithelial-mesenchymal transition (EMT), migration, and metastasis of NSCLC cells were determined in vitro and vivo. Direct functional targets of miR-331-3p were identified by luciferase reporter assay, western blot assay, immunohistochemical staining, and rescue assay. The downstream pathway regulated by miR-331-3p was identified by immunofluorescence, immunoprecipitation, and Rac1 activity examination. Our results showed that miR-331-3p was significantly downregulated in NSCLC tumor tissues and was correlated with clinicopathological characteristics, and miR-331-3p could be an independent prognostic marker for NSCLC patients. Furthermore, miR-331-3p significantly suppressed EMT, migration and metastasis of NSCLC cells in vitro and in vivo. Both ErbB2 and VAV2 were direct functional targets of miR-331-3p. The activities of Rac1, PAK1, and β-catenin were regulated by miR-331-3p through ErbB2 and VAV2 targeting. These results indicated that miR-331-3p suppresses EMT, migratory capacity, and metastatic ability by targeting ErbB2 and VAV2 through the Rac1/PAK1/β-catenin axis in NSCLC.