MicroRNA-30a increases tight junction protein expression to suppress the epithelial-mesenchymal transition and metastasis by targeting Slug in breast cancer

Single-Cell Fluidic Force Spectroscopy Reveals Dynamic Mechanical Fingerprints of Malignancy in Breast Cancer

The interplay between cancer cell physical characteristics and metastatic potential highlights the significance of cancer cell mechanobiology. Using fluidic-based single-cell force spectroscopy (SCFS), quartz crystal microbalance with dissipation (QCM-D), and a model of cells with a spectrum of metastatic potential, we track the progression of biomechanics across the metastatic states by measuring cell-substrate and cell-to-cell adhesion forces, cell spring constant, cell height, and cell viscoelasticity. Compared to highly metastatic cells, cells in the lower spectrum of metastatic ability are found to be systematically stiffer, less viscoelastic, and larger. These mechanical transformations in cells within a cluster correlate with cells' metastatic potential but are significantly absent in single cells. Additionally, the response to chemotherapy is found to be highly dependent on cell viscoelastic properties in terms of both response time and magnitude. Shifts in cell softness and elasticity might serve as mechanoadaptive mechanisms during cancer cell metastasis, contributing to our understanding of metastasis and the effectiveness of potential therapeutic interventions.

miR-622 Increases miR-30a Expression through Inhibition of Hypoxia-Inducible Factor 1α to Improve Metastasis and Chemoresistance in Human Invasive Breast Cancer Cells

Hypoxia-inducible factor 1α (HIF-1α) plays a pivotal role in the survival, metastasis, and response to treatment of solid tumors. Autophagy serves as a mechanism for tumor cells to eliminate misfolded proteins and damaged organelles, thus promoting invasiveness, metastasis, and resistance to treatment under hypoxic conditions. MicroRNA (miRNA) research underscores the significance of these non-coding molecules in regulating cancer-related protein synthesis across diverse contexts. However, there is limited reporting on miRNA-mediated gene expression studies, especially with respect to epithelial-mesenchymal transition (EMT) and autophagy in the context of hypoxic breast cancer. Our study reveals decreased levels of miRNA-622 (miR-622) and miRNA-30a (miR-30a) in invasive breast cancer cells compared to their non-invasive counterparts. Inducing miR-622 suppresses HIF-1α protein expression, subsequently activating miR-30a transcription. This cascade results in reduced invasiveness and migration of breast cancer cells by inhibiting EMT markers, such as Snail, Slug, and vimentin. Furthermore, miR-30a negatively regulates beclin 1, ATG5, and LC3-II and inhibits Akt protein phosphorylation. Consequently, this improves the sensitivity of invasive MDA-MB-231 cells to docetaxel treatment. In conclusion, our study highlights the therapeutic potential of inducing miR-622 to promote miR-30a expression and thus disrupt HIF-1α-associated EMT and autophagy pathways. This innovative strategy presents a promising approach to the treatment of aggressive breast cancer.

The crucial role of fascin-1 in the pathogenesis, metastasis, and chemotherapeutic resistance of breast cancer

Breast cancer (BC) is the most common type of cancer in women to be diagnosed, and it is also the second leading cause of cancer death in women globally. It is the disease that causes the most life years adjusted for disability lost among women, making it a serious worldwide health issue. Understanding and interpreting carcinogenesis and metastatic pathways is critical for curing malignancy. Fascin-1 was recognized as an actin-bundling protein with parallel, rigid bundles as a result of the cross-linking of F-actin microfilaments. Increasing levels of fascin-1 have been associated with bad prognostic profiles, aggressiveness of clinical courses, and poor survival outcomes in a variety of human malignancies. Cancer cells that overexpress fascin-1 have higher capabilities for proliferation, invasion, migration, and metastasis. Fascin-1 is being considered as a potential target for therapy as well as a potential biomarker for diagnostics in a variety of cancer types. This review aims to provide an overview of the FSCN1 gene and its protein structure, elucidate its physiological and pathological roles, and throw light on its involvement in the initiation, development, and chemotherapeutic resistance of BC.

Investigating malignancy-dependent mechanical properties of breast cancer cells

Cancer invasiveness significantly impacts cellular mechanical properties which regulate cell motility and, subsequently, cell metastatic potential. Understanding the adhesion forces and stiffness/rigidity of cancer cells can provide better insights into their mechanical adaptability related to their degree of invasiveness. Here, we used single-cell force spectroscopy in conjunction with quartz crystal microbalance-with dissipation measurements to compare the mechanical properties of mammary epithelial cancer cells with different metastatic potentials, namely MCF-7 (non-invasive) and MDA-MB-231 (aggressive and highly invasive). Our results showed that MCF-7 exhibits larger adhesion forces, stronger intercellular forces, and a considerably stiff/rigid phenotype, contrary to MDA-MB-231. The biomechanical properties obtained are associated with the malignant potential of these cells such that the forces of adhesion and viscoelasticity are inversely proportional to cell invasiveness. This study integrates a new quantitative tool with real-time measurements to provide better insights into the mechanics of cancer cells across metastatic stages.

MicroRNA Signatures in the Upper Urinary Tract Urothelial Carcinoma Scenario: Ready for the Game Changer?

Upper urinary tract urothelial carcinoma (UTUC) represents a minor subgroup of malignancies arising in the urothelium of the renal pelvis or ureter. The estimated annual incidence is around 2 cases per 100,000 people, with a mean age at diagnosis of 73 years. UTUC is more frequently diagnosed in an invasive or metastatic stage. However, even though the incidence of UTUC is not high, UTUC tends to be aggressive and rapidly progressing with a poor prognosis in some patients. A significant challenge in UTUC is ensuring accurate and timely diagnosis, which is complicated by the non-specific nature of symptoms seen at the onset of disease. Moreover, there is a lack of biomarkers capable of identifying the early presence of the malignancy and guide-tailored medical treatment. However, the growing understanding of the molecular biology underlying UTUC has led to the discovery of promising new biomarkers. Among these biomarkers, there is a class of small non-coding RNA biomarkers known as microRNAs (miRNAs) that are particularly promising. In this review, we will analyze the main characteristics of UTUC and focus on microRNAs as possible novel tools that could enter clinical practice in order to optimize the current diagnostic and prognostic algorithm.

miR-30a/SOX4 Double Negative Feedback Loop is modulated by Disulfiram and regulates EMT and Stem Cell-like properties in Breast Cancer

Background: Both epithelial-to-mesenchymal transition (EMT) and cancer stem cells play important roles in development and progression of breast cancer. MicroRNA (miR)-30 family members have been reported to be associated with the regulation of EMT and stem cell phenotypes, however, the underlying molecular mechanisms are not well understood.

Methods: miR-30a stable transfectants of breast cancer cell lines were created using a lentiviral system. Bioinformatics analysis was performed to explore miR-30a target genes and SOX4 was selected and identified by dual luciferase reporter assay. The effects of miR-30a and target gene SOX4 on EMT and CSC phenotypes in breast cancer were explored in vitro and in vivo.

Results: Overexpression of miR-30a in breast cancer cells inhibited EMT and CSC phenotypes by targeting SOX4. Luciferase reporter assay confirmed that miR-30a directly targeted 3'UTR of SOX4, and formed a double-negative feedback loop with SOX4. Functional experiments demonstrated that knockdown of SOX4 suppressed EMT and CSC phenotypes of breast cancer cells through TGF-β/SMAD pathway, which was consistent with the inhibitory effects by overexpression of miR-30a. Additionally, we found disulfiram can upregulate miR-30a expression, and high miR-30a expression was associated with a good prognosis in breast cancer patients through TCGA database.

Conclusion: Our findings suggest a novel double-negative loop between miR-30a and SOX4 mediated regulation of EMT and CSC features in breast cancer through TGF-β/SMAD pathway, highlighting a novel therapeutic target for breast cancer.

High miR-30 Expression Associates with Improved Breast Cancer Patient Survival and Treatment Outcome

Simple Summary

Previous research on the miR-30 family and breast cancer patient survival and on miR-30-related chemosensitivity prompted us to design a comprehensive study on the role of the miR-30 family in general and on miR-30d in particular in breast cancer. We present a study consisting of a tumor microarray analysis of 1238 breast cancer patients, a survival analysis, a drug-sensitivity screen with six breast cancer cell lines, and an in-silico pathway analysis. In our analysis, high miR-30d expression was associated with improved survival in breast cancer patients with aggressive tumor phenotypes. In the drug-sensitivity analysis, ectopic expression of miR-30 family members sensitized the cell lines to the treatment. The pathway analysis based on miRNA and mRNA expression in the METABRIC data suggested that the miR-30 family may have an inhibitory role in pathways contributing to EMT and metastasis. Our results suggest prognostic and predictive potential for the miR-30 family for further investigation.

Abstract

Deregulated miRNA expression has been suggested in several stages of breast cancer pathogenesis. We have studied the miR-30 family, in particular miR-30d, in relation to breast cancer patient survival and treatment outcomes. With tumor specimens from 1238 breast cancer patients, we analyzed the association of miR-30d expression with tumor characteristics with the 5-year occurrence of breast cancer-specific death or distant metastasis (BDDM), and with 10-year breast cancer survival (BCS). We conducted a two-stage drug-screen to investigate the impact of miR-30 family members (miR-30a-30e) on sensitivity to doxorubicin and lapatinib in six breast cancer cell lines HCC1937, HCC1954, MDA-MB-361, MCF7, MDA-MB-436 and CAL-120, using drug sensitivity scores (DSS) to compare the miR-30 family mimics to their specific inhibitors. The study was complemented with Ingenuity Pathway Analysis (IPA) with the METABRIC data. We found that while high miR-30d expression is typical for aggressive tumors, it predicts better metastasis-free (p_BDDM = 0.035, HR = 0.63, 95% CI = 0.4–0.9) and breast cancer-specific survival (p_BCS = 0.018, HR = 0.61, 95% CI = 0.4–0.9), especially in HER2-positive (p_BDDM = 0.0009), ER-negative (p_BDDM = 0.003), p53-positive (p_BDDM = 0.011), and highly proliferating (p_BDDM = 0.0004) subgroups, and after adjuvant chemotherapy (p_BDDM = 0.035). MiR-30d predicted survival independently of standard prognostic markers (p_BDDM = 0.0004). In the drug-screening test, the miR-30 family sensitized the HER2-positive HCC1954 cell line to lapatinib (p < 10⁻²) and HCC1937, MDA-MB-361, MDA-MB-436 and CAL120 to doxorubicin (p < 10⁻⁴) with an opposite impact on MCF7. According to the pathway analysis, the miR-30 family has a suppressive effect on cell motility and metastasis in breast cancer. Our results suggest prognostic and predictive potential for the miR-30 family, which warrants further investigation.

MiR-139 Modulates Cancer Stem Cell Function of Human Breast Cancer through Targeting CXCR4

Elevated expression of C-X-C motif chemokine receptor 4 (CXCR4) correlates with chemotaxis, invasion, and cancer stem cell (CSC) properties within several solid-tumor malignancies. Recent studies reported that microRNA (miRNA) modulates the stemness of embryonic stem cells. We aimed to investigate the role of miRNA, via CXCR4-modulation, on CSC properties in breast cancer using cell lines and xenotransplantation mouse model and evaluated miR-193 levels in 191 patients with invasive ductal carcinoma. We validated miR-139 directly targets the 3'-untranslated region of CXCR4. Hoechst 33342 fluorescence-activated cell sorting (FACS) and sphere-forming assay were used to identify CSCs. MiR-139 suppressed breast CSCs with mesenchymal traits; led to decreased migration and invasion abilities through down-regulating CXCR4/p-Akt signaling. In lung cancer xenograft model of nude mice transplanted with human miR-139-carrying MDA-MB-231 cells, metastatic lung nodules were suppressed. Clinically, microdissected breast tumor tissues showed miR-139 reduction, compared to adjacent non-tumor tissues, that was significantly associated with worse clinicopathological features, including larger tumor size, advanced tumor stage and lymph node metastasis; moreover, reduced miR-139 level was predominately occurred in late-stage HER2-oreexpression tumors. Collectively, our findings highlight miR-139-mediated suppression of CXCR4/p-Akt signaling and thereby affected mesenchymal stem-cell genesis, indicating its potential as a therapeutic target for invasive breast cancer.

Current research on circular RNAs and their potential clinical implications in breast cancer

Breast cancer (BC) is one of the most common cancers and the leading causes of death among women worldwide, and its morbidity rate is growing. Discovery of novel biomarkers is necessary for early BC detection, treatment, and prognostication. Circular RNAs (circRNAs), a novel type of endogenous non-coding RNAs with covalently closed continuous loops, have been found to have a crucial role in tumorigenesis. Studies have demonstrated that circRNAs are aberrantly expressed in the tumor tissues and plasma of patients with BC, and they modulate gene expression affecting the proliferation, metastasis, and chemoresistance of BC by specifically binding and regulating the expression of microRNAs (miRNAs). Therefore, circRNAs can be used as novel potential diagnostic and prognostic markers, and therapeutic targets for BC. This article summarizes the properties, functions, and regulatory mechanisms of circRNAs, particularly current research on their association with BC proliferation, metastasis, and chemoresistance.

Regulation of breast cancer metastasis signaling by miRNAs

Despite the decline in death rate from breast cancer and recent advances in targeted therapies and combinations for the treatment of metastatic disease, metastatic breast cancer remains the second leading cause of cancer-associated death in U.S. women. The invasion-metastasis cascade involves a number of steps and multitudes of proteins and signaling molecules. The pathways include invasion, intravasation, circulation, extravasation, infiltration into a distant site to form a metastatic niche, and micrometastasis formation in a new environment. Each of these processes is regulated by changes in gene expression. Noncoding RNAs including microRNAs (miRNAs) are involved in breast cancer tumorigenesis, progression, and metastasis by post-transcriptional regulation of target gene expression. miRNAs can stimulate oncogenesis (oncomiRs), inhibit tumor growth (tumor suppressors or miRsupps), and regulate gene targets in metastasis (metastamiRs). The goal of this review is to summarize some of the key miRNAs that regulate genes and pathways involved in metastatic breast cancer with an emphasis on estrogen receptor α (ERα+) breast cancer. We reviewed the identity, regulation, human breast tumor expression, and reported prognostic significance of miRNAs that have been documented to directly target key genes in pathways, including epithelial-to-mesenchymal transition (EMT) contributing to the metastatic cascade. We critically evaluated the evidence for metastamiRs and their targets and miRNA regulation of metastasis suppressor genes in breast cancer progression and metastasis. It is clear that our understanding of miRNA regulation of targets in metastasis is incomplete.

Regulators at Every Step-How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial-mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

Regulators at Every Step—How microRNAs Drive Tumor Cell Invasiveness and Metastasis

Tumor cell invasiveness and metastasis are the main causes of mortality in cancer. Tumor progression is composed of many steps, including primary tumor growth, local invasion, intravasation, survival in the circulation, pre-metastatic niche formation, and metastasis. All these steps are strictly controlled by microRNAs (miRNAs), small non-coding RNA that regulate gene expression at the post-transcriptional level. miRNAs can act as oncomiRs that promote tumor cell invasion and metastasis or as tumor suppressor miRNAs that inhibit tumor progression. These miRNAs regulate the actin cytoskeleton, the expression of extracellular matrix (ECM) receptors including integrins and ECM-remodeling enzymes comprising matrix metalloproteinases (MMPs), and regulate epithelial–mesenchymal transition (EMT), hence modulating cell migration and invasiveness. Moreover, miRNAs regulate angiogenesis, the formation of a pre-metastatic niche, and metastasis. Thus, miRNAs are biomarkers of metastases as well as promising targets of therapy. In this review, we comprehensively describe the role of various miRNAs in tumor cell migration, invasion, and metastasis.

MiR-30a suppresses metastasis of gastric adenocarcinoma via targeting FAPα

BACKGROUND

Gastric cancer is one of the leading causes of death worldwide. MicroRNA-30a (miR-30a) has been demonstrated to be involved in several types of cancer development.

OBJECTIVE

We aimed to identify the molecular mechanism of miR-30a in gastric cancer.

METHODS

We investigated the expression of miR-30a in gastric cancer tissues by qRT-PCR. The role of miR-30a on the metastasis and proliferation of gastric cancer was evaluated by cell migration assay, CCK-8 assay and tumor peritoneal dissemination model. The target of miR-30a in gastric cancer was identified.

RESULTS

We discovered that miR-30a was significantly downregulated in gastric cancer tissues compared with adjacent nonmalignant tissues. The expression of miR-30a was inversely correlated with progression of gastric cancer. Gain- and loss-of function revealed that miR-30a acted as a potent tumor suppressor in gastric cancer. Re-expressed miR-30a inhibited gastric cancer cells migration, knock down miR-30a have the opposite effects. Furthermore, overexpression of miR-30a suppressed tumor peritoneal dissemination in vivo. We identified that fibroblast activation protein α (FAPα) was a direct target of miR-30a. The relative expression of FAPα was significantly higher in gastric cancer tissues compared with adjacent nonmalignant tissues. Inhibition of FAPα could recapitulate the effects of miR-30a, and overexpression of FAPα could abrogate the effect of miR-30a.

CONCLUSION

MiR-30a inhibited gastric cancer metastasis by targeting FAPα, suggesting that miR-30a may function as a novel tumor suppressor in gastric cancer.

Mutually distinguishing microRNA signatures of breast, ovarian and endometrial cancers in vitro

Early diagnosis and therapy in the first stages of a malignant disease is the most crucial factor for successful cancer treatment and recovery. Currently, there is a high demand for novel diagnostic tools that indicate neoplasms in the first or pre‑malignant stages. MicroRNAs (miRNA or miR) are small non‑coding RNAs that may act as oncogenes and downregulate tumor‑suppressor genes. The detection and mutual discrimination of the three common female malignant neoplasia types breast (BC), ovarian (OC) and endometrial cancer (EC) could be enabled by identification of tumor entity‑specific miRNA expression differences. In the present study, the relative expression levels of 25 BC, EC and OC‑related miRNAs were assessed by reverse transcription‑quantitative PCR and determined using the 2‑ΔΔCq method for normalization against the mean of four housekeeping genes. Expression levels of all miRNAs were analyzed by regression against cell line as a factor. An expression level‑based discrimination between BC and OC cell types was obtained for a subgroup of ten different miRNA types. miR‑30 family genes, as well as three other miRNAs, were found to be uniformly upregulated in OC cells compared with BC cells. BC and EC cells could be distinguished by the expression profiles of six specific miRNAs. In addition, four miRNAs were differentially expressed between EC and OC cells. In conclusion, miRNAs were identified as a potential novel tool to detect and mutually discriminate between BC, OC and EC. Based on a subset of 25 clinically relevant human miRNA types, the present study could significantly discriminate between these three female cancer types by means of their expression levels. For further verification and validation of miRNA‑based biomarker expression signatures that enable valuable tumor detection and characterization in routine screening or potential therapy monitoring, additional and extended in vitro analyses, followed by translational studies utilizing patients' tissue and liquid biopsy materials, are required.

Mast cells-derived MiR-223 destroys intestinal barrier function by inhibition of CLDN8 expression in intestinal epithelial cells

Background

Mast cells (MCs) have been found to play a critical role during development of inflammatory bowel disease (IBD) that characterized by dysregulation of inflammation and impaired intestinal barrier function. However, the function of MCs in IBD remains to be fully elucidated.

Results

In our study, we used exosomes isolated from human mast cells-1 (HMCs-1) to culture with NCM460, HT-29 or CaCO2 of intestinal epithelial cells (IECs) to investigate the communication between MCs and IECs. We found that MCs-derived exosomes significantly increased intestinal epithelial permeability and destroyed intestinal barrier function, which is attributed to exosome-mediated functional miRNAs were transferred from HMCs-1 into IECs, leading to inhibit tight junction-related proteins expression, including tight junction proteins 1 (TJP1, ZO-1), Occludin (OCLN), Claudin 8 (CLDN8). Microarray and bioinformatic analysis have further revealed that a panel of miRNAs target different tight junction-related proteins. Interestingly, miR-223 is enriched in mast cell-derived exosome, which inhibit CLDN8 expression in IECs, while treatment with miR-223 inhibitor in HT-29 cells significantly reversed the inhibitory effect of HMCs-1-derived exosomes on CLDN 8 expression. Most importantly, enrichment of MCs accumulation in intestinal mucosa of patients with IBD compared with those healthy control.

Conclusions

These results indicated that enrichment of exosomal miR-223 from HMCs-1 inhibited CLDN8 expression, leading to destroy intestinal barrier function. These finding provided a novel insight of MCs as a new target for therapeutic treatment of IBD.

Interplay among SNAIL Transcription Factor, MicroRNAs, Long Non-Coding RNAs, and Circular RNAs in the Regulation of Tumor Growth and Metastasis

SNAIL (SNAI1) is a zinc finger transcription factor that binds to E-box sequences and regulates the expression of genes. It usually acts as a gene repressor, but it may also activate the expression of genes. SNAIL plays a key role in the regulation of epithelial to mesenchymal transition, which is the main mechanism responsible for the progression and metastasis of epithelial tumors. Nevertheless, it also regulates different processes that are responsible for tumor growth, such as the activity of cancer stem cells, the control of cell metabolism, and the regulation of differentiation. Different proteins and microRNAs may regulate the SNAIL level, and SNAIL may be an important regulator of microRNA expression as well. The interplay among SNAIL, microRNAs, long non-coding RNAs, and circular RNAs is a key event in the regulation of tumor growth and metastasis. This review for the first time discusses different types of regulation between SNAIL and non-coding RNAs with a focus on feedback loops and the role of competitive RNA. Understanding these mechanisms may help develop novel therapeutic strategies against cancer based on microRNAs.

Connexin43 as a Tumor Suppressor: Proposed Connexin43 mRNA-circularRNAs-microRNAs Axis Towards Prevention and Early Detection in Breast Cancer

Breast cancer (BC) is a global public health burden, constituting the highest cancer incidence in women worldwide. Connexin43 (Cx43) is a member of a family of transmembrane proteins responsible in part for intercellular communication between adjacent breast epithelial cells, via gap junctions. Cx43 plays key role in mammary gland development and differentiation and its spatio-temporal perturbation contributes to tumorigenesis. Thus, Cx43 acts as a breast tumor-suppressor. Signaling pathways and phenotypes downstream of Cx43 mRNA loss/mis-localization in breast cells have been well-studied. However, axes parallel to Cx43 loss are less understood. microRNAs (miRNAs) are small endogenous non-coding RNAs that repress translation and circularRNAs (circRNAs) are a class of endogenous RNAs that originate from RNA splicing and act as miRNA "sponges". CircRNAs and miRNAs are dysregulated in cancers and are highly abundant and stable in the circulation. Thus, they present as attractive liquid biopsy cancer biomarkers. Here, an axis for Cx43 mRNA-circRNAs-miRNAs interactions along BC initiation (denoted by loss of breast epithelial polarity and development of hyperplastic phenotypes) is proposed to potentially serve as a signature biomarker toward BC early-onset detection and prevention.

Comparative analysis of milk microRNA in the therian lineage highlights the evolution of lactation

Milk is a complex secretion that has an important role in mammalian reproduction. It is only recently that sequencing technologies have allowed the identification and quantification of microRNA (miRNA) in milk of a growing number of mammalian species. This provides a novel window on the study of the evolution and functionality of milk through the comparative analysis of milk miRNA content. Here, milk miRNA sequencing data from five species (one marsupial (tammar wallaby) and four eutherians (human, mouse, cow and pig)) have been retrieved from public depositories and integrated in order to perform a comparison of milk miRNA profiles. The study shows that milk miRNA composition varies widely between species, except for a few miRNAs that are ubiquitously expressed in the milk of all mammals and indicates that milk miRNA secretion has broadly evolved during mammalian evolution. The putative functions of the most abundant milk miRNAs are also discussed.

NF-κB inhibitor, BAY11-7082, suppresses M2 tumor-associated macrophage induced EMT potential via miR-30a/NF-κB/Snail signaling in bladder cancer cells

BACKGROUND

Chronic inflammatory microenvironment has been shown to play a key role in initiating tumorigenesis and facilitating malignant progression. Primary tumors surrounded with and infiltrated by tumor-associated macrophages (TAMs) significantly promote the epithelial-to-mesenchymal transition (EMT) and distant metastasis in urothelial bladder cancer.

METHODS

In this study, we aimed to explore the potential of targeting TAMs for the treatment of malignant bladder cancer.

RESULTS

First, we found a higher number of TAMs, CD68 (pan-macrophage marker), and clever-1 (M2 macrophage marker) was associated with a higher pT category and grade in a cohort of 108 patients. In vitro assays showed that the co-culture of TAMs promoted the metastatic potential in HTB-1 and T24 by up-regulating EMT markers including Snail, VEGF and Vimentin, as well as oncogenic markers such as β-catenin and NF-κB. More importantly, M2 co-cultured HTB-1 and T24 showed an increased level of metastatic microRNA, miR-30. Silencing of miR-30 resulted in the reduced metastatic potential, migration/invasion, in association with the decreased expression of Twist1 and Vimentin. The addition of BAY11-7082 into the TAM/cancer co-culture system significantly reduced the M2 phenotype and tumorigenic properties. Coincidentally, miR-30a level was significantly lowered in the presence of BAY11-7082.

CONCLUSION

Our study demonstrated that AMs promoted metastatic potential of bladder cancer cells via promoting EMT through the increase of miR-30a. BAY11-7082 treatment suppressed both oncogenic and metastatic potential in bladder cancer cells while preventing the M2 polarization of TAMs.

Tight Junction Proteins and Signaling Pathways in Cancer and Inflammation: A Functional Crosstalk

The ability of epithelial cells to organize through cell–cell adhesion into a functioning epithelium serves the purpose of a tight epithelial protective barrier. Contacts between adjacent cells are made up of tight junctions (TJ), adherens junctions (AJ), and desmosomes with unique cellular functions and a complex molecular composition. These proteins mediate firm mechanical stability, serves as a gatekeeper for the paracellular pathway, and helps in preserving tissue homeostasis. TJ proteins are involved in maintaining cell polarity, in establishing organ-specific apical domains and also in recruiting signaling proteins involved in the regulation of various important cellular functions including proliferation, differentiation, and migration. As a vital component of the epithelial barrier, TJs are under a constant threat from proinflammatory mediators, pathogenic viruses and bacteria, aiding inflammation and the development of disease. Inflammatory bowel disease (IBD) patients reveal loss of TJ barrier function, increased levels of proinflammatory cytokines, and immune dysregulation; yet, the relationship between these events is partly understood. Although TJ barrier defects are inadequate to cause experimental IBD, mucosal immune activation is changed in response to augmented epithelial permeability. Thus, the current studies suggest that altered barrier function may predispose or increase disease progression and therapies targeted to specifically restore the barrier function may provide a substitute or supplement to immunologic-based therapies. This review provides a brief introduction about the TJs, AJs, structure and function of TJ proteins. The link between TJ proteins and key signaling pathways in cell proliferation, transformation, and metastasis is discussed thoroughly. We also discuss the compromised intestinal TJ integrity under inflammatory conditions, and the signaling mechanisms involved that bridge inflammation and cancer.

miR-30a Inhibits Melanoma Tumor Metastasis by Targeting the E-cadherin and Zinc Finger E-box Binding Homeobox 2

Background:

Epithelial–mesenchymal transition (EMT) is actively involved in tumor invasion. The main hallmark of EMT is downregulation of the adherens junction protein E-cadherin due to transcriptional repression. Candidate E-cadherin transcription repressors are members of ZEB family, ZEB2 belong to the ZEB family transcription factor that is pivotal for embryonic development and tumor progression. ZEB2 (zinc finger E-box binding homeobox 2) is most widely known as an inducer of EMT. Growing evidence have shown the involvement of microRNAs in cancer progression. In this study, we demonstrate that miR-30a is a potent suppressor of melanoma metastasis to the lung.

Materials and Methods:

In this study, miR-30a has been transfected into B16-F10 melanoma cells, and then cells were injected intravenously into C57BL/6 mice. Then, the mice were sacrificed and nodules in the lungs were enumerated.

Results:

Ectopic expression of miR-30a in melanoma cell line resulted in the suppression of pulmonary metastasis. We also found that transfected miR-30a into melanoma cells could increase E-cadherin and decrease ZEB2 expression.

Conclusions:

Our findings showed that increased expression of miR-30a in melanoma inhibited metastasis in vivo by targeting ZEB2 and E-cadherin.

MicroRNA-30a suppresses the proliferation, migration and invasion of human renal cell carcinoma cells by directly targeting ADAM9

An increasing number of studies reported that microRNA (miR)-30a was dysregulated in several types of human cancer and may contribute to cancer carcinogenesis and progression. However, its expression and roles in renal cell carcinoma (RCC) remain unknown. In the present study, reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to quantify miR-30a expression in RCC tissues and cell lines. The cell counting kit-8 assay, migration and invasion assays were used to evaluate the roles of miR-30a on the proliferation, migration and invasion of RCC cells. The target gene of miR-30a was identified by luciferase reporter assays, RT-qPCR and western blotting. The results indicated that miR-30a was downregulated in RCC tissues and cell lines compared with corresponding noncancerous tissues and normal renal cell line, respectively. Re-expression of miR-30a inhibited the proliferation, migration and invasion of RCC cells. Additionally, ADAM metallopeptidase domain 9 (ADAM9) was validated as a direct target of miR-30a. Furthermore, the knockdown of ADAM9 by small interfering RNAs was able to mimic the effects of miR-30a overexpression in RCC cells. These results highlight the important role for miR-30a in the occurrence and development of RCC, and the restoration of miR-30a might be investigated as a potential strategy for treating RCC.

MiR-30a: A Novel Biomarker and Potential Therapeutic Target for Cancer

MicroRNAs (miRNAs) are small, highly conserved noncoding RNAs molecules, consisting of 18–25 nucleotides that regulate gene expression by binding to complementary binding sites within the 3′untranslated region (3′UTR) of target mRNAs. MiRNAs have been involved in regulating gene expression and diverse physiological and pathological processes. Several studies have reported that miR-30a, situated on chromosome 6q.13, is produced by an intronic transcriptional unit. Moreover, miR-30a has demonstrated its role in biological processes, including inhibiting proliferation and metastasis in many tumors, autophagy in chronic myelogenous leukemia, and regulating TGF-b1-induced epithelial-mesenchymal transition. However, based on the pathogenetic relationship between miR-30a and cancer in tumorigenesis, we believe that miR-30a may serve as tumor promising biomarker. Moreover, it would offer a therapeutic target for the treatment of cancer.

Functional Role of Non-Coding RNAs during Epithelial-To-Mesenchymal Transition

Epithelial-to-mesenchymal transition (EMT) is a key biological process involved in a multitude of developmental and pathological events. It is characterized by the progressive loss of cell-to-cell contacts and actin cytoskeletal rearrangements, leading to filopodia formation and the progressive up-regulation of a mesenchymal gene expression pattern enabling cell migration. Epithelial-to-mesenchymal transition is already observed in early embryonic stages such as gastrulation, when the epiblast undergoes an EMT process and therefore leads to the formation of the third embryonic layer, the mesoderm. Epithelial-to-mesenchymal transition is pivotal in multiple embryonic processes, such as for example during cardiovascular system development, as valve primordia are formed and the cardiac jelly is progressively invaded by endocardium-derived mesenchyme or as the external cardiac cell layer is established, i.e., the epicardium and cells detached migrate into the embryonic myocardial to form the cardiac fibrous skeleton and the coronary vasculature. Strikingly, the most important biological event in which EMT is pivotal is cancer development and metastasis. Over the last years, understanding of the transcriptional regulatory networks involved in EMT has greatly advanced. Several transcriptional factors such as Snail, Slug, Twist, Zeb1 and Zeb2 have been reported to play fundamental roles in EMT, leading in most cases to transcriptional repression of cell⁻cell interacting proteins such as ZO-1 and cadherins and activation of cytoskeletal markers such as vimentin. In recent years, a fundamental role for non-coding RNAs, particularly microRNAs and more recently long non-coding RNAs, has been identified in normal tissue development and homeostasis as well as in several oncogenic processes. In this study, we will provide a state-of-the-art review of the functional roles of non-coding RNAs, particularly microRNAs, in epithelial-to-mesenchymal transition in both developmental and pathological EMT.

A p53/miR-30a/ZEB2 axis controls triple negative breast cancer aggressiveness

Inactivation of p53 contributes significantly to the dismal prognosis of breast tumors, most notably triple-negative breast cancers (TNBCs). How the relief from p53 tumor suppressive functions results in tumor cell aggressive behavior is only partially elucidated. In an attempt to shed light on the implication of microRNAs in this context, we discovered a new signaling axis involving p53, miR-30a and ZEB2. By an in silico approach we identified miR-30a as a putative p53 target and observed that in breast tumors reduced miR-30a expression correlated with p53 inactivation, lymph node positivity and poor prognosis. We demonstrate that p53 binds the MIR30A promoter and induces the transcription of both miRNA strands 5p and 3p. Both miR-30a-5p and -3p showed the capacity of targeting ZEB2, a transcription factor involved in epithelial–mesenchymal transition (EMT), tumor cell migration and drug resistance. Intriguingly, we found that p53 does restrain ZEB2 expression via miR-30a. Finally, we provide evidence that the new p53/miR-30a/ZEB2 axis controls tumor cell invasion and distal spreading and impinges upon miR-200c expression. Overall, this study highlights the existence of a novel axis linking p53 to EMT via miR-30a, and adds support to the notion that miRNAs represent key elements of the complex network whereby p53 inactivation affects TNBC clinical behavior.

Employing an orthotopic model to study the role of epithelial-mesenchymal transition in bladder cancer metastasis

Epithelial-to-mesenchymal transition (EMT) has been implicated in the progression of bladder cancer. To study its contribution to bladder cancer metastasis, we established new xenograft models derived from human bladder cancer cell lines utilizing an orthotopic “recycling” technique that allowed us to isolate and examine the primary tumor and its corresponding circulating tumor cells (CTC’s) and metastatic lesions. Using whole genome mRNA expression profiling, we found that a reversible epithelial-to-mesenchymal transition (EMT) characterized by TGFβ pathway activation and SNAIL expression was associated with the accumulation of CTCs. Finally, we observed that conditional silencing of SNAIL completely blocked CTC production and regional/distant metastasis. Using this unique bladder cancer xenograft model, we conclude that metastasis is dependent on a reversible EMT mediated by SNAIL.

Overexpression of suppressive microRNAs, miR-30a and miR-200c are associated with improved survival of breast cancer patients

Some microRNAs (miRNAs) are known to suppress breast cancer. However, whether the expressions of these tumor suppressive miRNAs translate to patient survival were not investigated in large cohort. Nine miRNAs (miR-30a, miR-30c, miR-31, miR-126, miR-140, miR-146b, miR-200c, miR-206, and miR-335) known to be tumor suppressive miRNAs in breast cancer were investigated in Genomic Data Common data portal miRNA-Seq dataset and The Cancer Genome Atlas (TCGA) (n = 1052). Of the 9 miRNAs, miR-30a, miR-30c, miR-126, miR-140, miR-206, and miR-335 were found to have significantly lower expression in breast cancer tissues compared to paired normal breast tissue. High expression of miR-30a or miR-200c was associated with significantly better overall survival (OS). Gene Set Enrichment Analysis (GSEA) demonstrated that low expression levels of miR-30a had the tendency to associate with gene enrichment of EMT, while miR-200c did not, in TCGA cohort, and our findings support the need of validation using large cohort to use miRNA as prognostic biomarker for patients with breast cancer.

MiR-301b promotes the proliferation, mobility, and epithelial-to-mesenchymal transition of bladder cancer cells by targeting EGR1

We investigated the role of miR-301b in the modulation of the proliferation, migration, and invasion of bladder cancer (BLCA) cells. The expression of miR-301b and EGR1 (early growth response gene 1) mRNA were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR). A dual-luciferase reporter gene system was used to identify the target relationship between miR-301b and EGR1. Cell proliferation, cell cycle, and apoptosis were analyzed by MTT assay, colony-forming assay, and flow cytometry, respectively. Cell motility and invasiveness were assessed by wound healing and Transwell assays. The expression of proteins involved in epithelial-to-mesenchymal transition (EMT) and EGR1 were determined by Western blot. Our results showed that miR-301b was up-regulated while EGR1 was down-regulated in BLCA tissues compared with adjacent normal tissues. The proliferation, migration, and invasiveness of T24 cells (a kind of human BLCA cell) were suppressed by decreasing miR-301b expression or increasing EGR1 expression. In addition, miR-301b promoted EMT signaling by influencing the expression of related proteins. In conclusion, miR-301b promotes the proliferation, migration, and aggressiveness of human BLCA cells by inhibiting the expression of EGR1.

MiR-30a-5p Inhibits Epithelial-to-Mesenchymal Transition and Upregulates Expression of Tight Junction Protein Claudin-5 in Human Upper Tract Urothelial Carcinoma Cells

The involvement of microRNAs (miRNAs) in cancer development and their potential as prognostic biomarkers are becoming increasingly known. However, the signature of miRNAs and their regulatory roles in tumorigenesis of upper tract urothelial carcinoma (UTUC) remain to be elucidated. This study aimed to profile the miRNA expression pattern in UTUC tumor tissues and identify candidate miRNAs with prognostic and/or therapeutic functions. Methods and Results: We collected 22 UTUC tissue and adjacent normal tissues samples from patients who underwent nephroureterectomy. The miRNAs signatures of three selected UTUC samples using next-generation sequencing showed that miR-30a-5p was significantly downregulated in UTUC tumors compared to adjacent normal tissues. The differentially-expressed miRNAs were specifically validated by quantitative real-time polymerase chain reaction. In addition, the miRNA expression signatures were analyzed with the transcriptome profile characterized by microarray. Further in vitro studies indicated that overexpression of miR-30a-5p significantly suppressed proliferation, migration, and epithelial-to-mesenchymal transition (EMT) in cultured BFTC-909 UTUC cells. As a potential target gene of miR-30a-5p in the tight junction pathway suggested by the pathway enrichment analysis, the reduced expression of tight junction protein claudin-5 in UTUC cells was demonstrated to be upregulated by miR-30a-5p genetic delivery. Conclusions: Taken together, our findings demonstrated that miR-30a-5p inhibits proliferation, metastasis, and EMT, and upregulates the expression of tight junction claudin-5 in UTUC cells. Thus, miR-30a-5p may provide a promising therapeutic strategy for UTUC treatment.

Interrelation of androgen receptor and miR-30a and miR-30a function in ER-, PR-, AR+ MDA-MB-453 breast cancer cells

The association between androgen-induced androgen receptor (AR) activating signal and microRNA (miR)-30a was investigated, as well as the function of miR-30a in estrogen receptor-negative (ER^-), progesterone receptor-negative (PR^-), and AR-positive (AR⁺) MDA-MB-453 breast cancer cells. Androgen-induced AR activating signal upregulated the expression of AR, and downregulated the expression of miR-30a, b and c. Bioinformatics analysis indicated a putative miR-30a, b and c binding site in the 3'-untranslated region of AR mRNA. It was confirmed that the AR gene is a direct target of miR-30a, whereas AR does not target the miR-30a promoter, and AR activating signal may indirectly downregulate miR-30a through other cell signaling pathways. In this positive feedback mechanism AR is then upregulated through miR-30a. Overexpression of miR-30a inhibited cell proliferation, whereas inhibition of miR-30a expression by specific antisense oligonucleotides, increased cell growth. Previously, androgen-induced AR activating signal was demonstrated to inhibit cell proliferation in ER^-, PR^- and AR⁺ MDA-MB-453 breast cancer cells, but AR activating signal downregulated the expression of miR-30a, relieving the inhibition of MDA-MB-453 cell growth. Therefore, in MDA-MB-453 breast cancer cells, miR-30a has two different functions regarding cell growth: Inhibition of cell proliferation through a positive feedback signaling pathway; and the relative promotion of cell proliferation through downregulation of miR-30a. Thus, the association between AR activating signal and microRNAs is complex, and microRNAs may possess different functions due to different signaling pathways. Although the results of the present study were obtained in one cell line, they contribute to subsequent studies on ER^-, PR^- and AR⁺ breast cancer.

Norcantharidin induces mitochondrial-dependent apoptosis through Mcl-1 inhibition in human prostate cancer cells

Norcantharidin (NCTD) is the demethylated form of cantharidin that exhibits anticancer potential in many cancer cell types. Recent reports suggest that NCTD targeting ROS/AMPK and DNA replication signaling pathway could be an effective strategy for the treatment of PCa cells. However, supportive evidence is limited to the effect of NCTD that induction of apoptosis through suppression of the Mcl-1. Here, we show that NCTD induced PCa cell apoptosis and triggered caspase activation, which was associated with mitochondria dysfunction. Mechanistic investigations suggested that NCTD modulated the Akt signaling via increased nuclear translocation and interaction with the myeloid cell leukemia-1 (Mcl-1) promoter by FOXO4, resulting in an apoptotic effect. Moreover, miR-320d, which targets Mcl-1, was significantly upregulated after NCTD treatment. Overexpression of miR-320d by NCTD induced mitochondria dysfunction and apoptosis, which was notably attenuated with a miR-320d inhibitor. In vivo xenograft analysis revealed that NCTD significantly reduced tumor growth in mice with PC3 tumor xenografts. Taken together, our results provide new insights into the critical role of NCTD in suppressing Mcl-1 via epigenetic upregulation of miR-320d, resulting in PCa cell apoptosis.

CircRNA: a novel type of biomarker for cancer

Circular RNAs (circRNAs) are a class of long, non-coding RNAs molecules that shape a covalently closed continuous loop which have no 5'-3' polarity and contain no polyA tail. CircRNAs also possess relatively jarless framework and are highly tissue-specific expressed in the eukaryotic transcriptome. Emerging evidences have discovered that thousands of endogenous circRNAs are present in mammalian cells and they mediate gene expression at the transcriptional or post-transcriptional level by binding to microRNAs or other molecules and then inhibit their function. Similarly, increasing evidence indicates that circRNAs may play a role in the development of several types of diseases, including atherosclerotic vascular disease risk, neurological disorders, prion diseases, osteoarthritis and diabetes. Furthermore, circRNAs exhibit aberrant expression in multiform types of cancer, including colorectal cancer, hepatocellular carcinoma and pancreatic ductal adenocarcinoma. And based on the function of circRNAs in cancer, we believe that circRNAs may serve as diagnostic or tumor promising biomarkers. Moreover, it will provide a new therapeutic target for the treatment of cancer.

MicroRNA-630 Suppresses Epithelial-to-Mesenchymal Transition by Regulating FoxM1 in Gastric Cancer Cells

In the present study, we investigated the functional role of microRNA (miR)-630 in epithelial-to-mesenchymal transition (EMT) of gastric cancer (GC) cells, as well as the regulatory mechanism. Cells of human GC cell line SGC 7901 were transfected with miR-630 mimic or miR-630 inhibitor. The transfection efficiency was confirmed by qRT-PCR. Cell migration and invasion were determined by Transwell assay. Protein expression of E-cadherin, vimentin, and Forkhead box protein M1 (FoxM1) was tested by Western blot. Moreover, the expression of FoxM1 was elevated or suppressed, and then the effects of miR-630 abnormal expression on EMT and properties of migration and invasion were examined again, as well as protein expression of Ras/phosphoinositide 3-kinase (PI3K)/AKT related factors. The results showed that (i) the EMT and properties of migration and invasion were statistically decreased by overexpression of miR-630 compared to the control group but markedly increased by suppression of miR-630. However, (ii) abnormal expression of FoxM1 reversed these effects in GC cells. Moreover, (iii) expression of GTP-Rac1, p-PI3K, and p-AKT was decreased by miR-630 overexpression but increased by FoxM1 overexpression. (iv) The decreased levels of GTP-Rac1, p-PI3K, and p-AKT induced by miR-630 overexpression were dramatically elevated by simultaneous overexpression of FoxM1. In conclusion, our results suggest that miR-630 might be a tumor suppressor in GC cells. MiR-630 suppresses EMT by regulating FoxM1 in GC cells, supposedly via inactivation of the Ras/PI3K/AKT pathway.

MicroRNA-30a functions as tumor suppressor and inhibits the proliferation and invasion of prostate cancer cells by down-regulation of SIX1

Increasing reports have demonstrated that aberrant expression of microRNAs (miRNAs) is found in multiple human cancers. Many studies have shown that down-regulated level of miR-30a is in a variety of cancers including prostate cancer (PCa). However, the precise mechanisms of miR-30a in PCa have not been well explored. In this study, we investigated the biological functions and molecular mechanism of miR-30a in PCa cell lines, discussing whether it could be a therapeutic biomarker of PCa in the future. We found that miR-30a is down-regulated in PCa tissues and cell lines. Moreover, the low level of miR-30a was associated with increased expression of SIX1 in PCa tissues and cell lines. Up-regulation of miR-30a significantly inhibited proliferation of PCa cells. In addition, invasion of PCa cells was suppressed by overexpression of miR-30a. However, down-regulation of miR-30a promoted cell growth and invasion of PCa cells. Bioinformatics analysis predicted that the SIX1 was a potential target gene of miR-30a. Next, luciferase reporter assay confirmed that miR-30a could directly target SIX1. Consistent with the effect of miR-30a, down-regulation of SIX1 by siRNA inhibited proliferation and invasion of PCa cells. Overexpression of SIX1 in PCa cells partially reversed the effect of miR-30a mimic. In conclusion, introduction of miR-30a dramatically inhibited proliferation and invasion of PCa cells by down-regulating SIX1 expression, and that down-regulation of SIX1 was essential for inhibition of cell growth and invasion of PCa cells by overexpression of miR-30a.

The role of miR-130a in cancer

MicroRNAs (miRs) are short and highly conserved non-coding RNAs molecules consisting of 18-25 nucleotides that regulate gene expression at post-transcriptional level by direct binding to complementary binding sites within the 3'untranslated region (3'UTR) of target mRNAs. New evidences have demonstrated that miRNAs play an important role in diverse physiological processes, including regulating cell growth, apoptosis, metastasis, drug resistance, and invasion. In chromosomes 11 and 22 of the miR-130 family, paralogous miRNA sequences, miR-130a and miR-130b are situated, respectively. MiR-130a has participated in different pathogenesis, including hepatocellular carcinoma, cervical cancer, ovarian cancer, glioblastoma, prostate carcinoma, leukemia, etc. Most important of all, more and more evidences indicate that miR-130a is associated with drug resistance and acts as an intermediate in PI3 K/Akt/PTEN/mTOR, Wnt/β-catenin and NF-kB/PTEN drug resistance signaling pathways. Drug resistance has emerged as a major obstacle to successful treatment of cancer nowadays and in this review, we will reveal the function of miR-130a in cancer, especially in drug resistance. Therefore, it will provide a new therapeutic target for the treatment of cancer, especially in chemotherapy.

IGF-I Induces Epithelial-to-Mesenchymal Transition via the IGF-IR-Src-MicroRNA-30a-E-Cadherin Pathway in Nasopharyngeal Carcinoma Cells

Recurrence and distant metastasis are the most common cause of therapeutic failure in nasopharyngeal carcinoma (NPC) patients. Insulin-like growth factor I (IGF-I) can induce epithelial-to-mesenchymal transition (EMT) in many epithelial tumors; however, whether IGF-I can enhance NPC metastasis by EMT and the mechanisms remain unclear. Herein, we have identified that IGF-I could induce EMT and enhance migration ability in NPC cell lines. Furthermore, both Src inhibitor and microRNA-30a (miR-30a) inhibitor reversed IGF-I-induced EMT, suggesting the involvement of an IGF-IR-Src-miR-30a-E-cadherin pathway in IGF-I-induced EMT in NPC cell lines. Overall, the results of the present study may provide more useful information regarding the mechanisms of the IGF-IR signaling pathway in the regulation of NPC metastasis. Both Src kinase and miR-30a can be potential biomarkers for selecting high risk of metastasis in NPC patients.

MicroRNAs regulate the epithelial-mesenchymal transition and influence breast cancer invasion and metastasis

MicroRNAs are small RNA molecules that play a major role in the post-transcriptional regulation of genes and influence the development, differentiation, proliferation, and apoptosis of cells and the development and progression of tumors. The epithelial-mesenchymal transition is a process by which epithelial cells morphologically transform into cells with a mesenchymal phenotype. The epithelial-mesenchymal transition plays a highly important role in tumor invasion and metastasis. Increasing evidence indicates that microRNAs are tightly associated with epithelial-mesenchymal transition regulation in tumor cells. In breast cancer, various microRNA molecules have been identified as epithelial-mesenchymal transition inducers or inhibitors, which, through different mechanisms and signaling pathways, participate in the regulation of breast cancer invasion and metastasis among various biological behaviors. The epithelial-mesenchymal transition-related microRNAs in breast cancer provide valuable molecules for researching cell invasion and metastasis, and they also provide candidate targets that may be significant for the targeted therapy of breast cancer.

A Feedback Loop Between miR-30a/c-5p and DNMT1 Mediates Cisplatin Resistance in Ovarian Cancer Cells

BACKGROUND

Many microRNAs (miRs) are dysregulated in cancers, and aberrant miR expression patterns have been suggested to correlate with chemo-resistance of cancer cells. We aim to study the role of miR-30 family members in cisplatin-resistance of ovarian cancer cells.

METHODS

qRT-PCR was used to compare differential expression levels of miR-30 family members in ovarian cancer cell line A2780 and its cisplatin-resistant derivative CP70. Changes of cisplatin-sensitivity in miR-30a-5p- and miR-30c-5p-overexpressed-CP70 cells and miR-30a-5p- and miR-30c-5p-inhibited-A2780 cells were examined by CCK8 assay and apoptosis analysis using flow cytometry; targets of miR-30a/c-5p were analyzed by western blotting and luciferase reporter assay; methylation regulation of pre-miR-30a/c-5p was examined by methylation specific PCR.

RESULTS

miR-30a-5p and miR-30c-5p, in contrast to other miR-30 family members, dramatically decreased in cisplatin-resistant CP70 cells due to overexpressed-DNMT1 induced aberrant methylation. miR-30a/c-5p in turn directly inhibited DNMT1 as well as Snail. Forced expression of miR-30a/c-5p or knocking down of DNMT1 and Snail promoted cisplatin susceptibility and partially reversed epithelial-mesenchymal transition (EMT) in CP70 cells, while inhibition of miR-30a/c-5p or ectopic expression of DNMT1 and Snail induced cisplatin resistance and partial EMT in cisplatin-sensitive A2780 cells.

CONCLUSIONS

A feedback loop between miR-30a/c-5p and DNMT1 is a potent signature for cisplatin-resistance and EMT in ovarian cancer, promising a potential target for improved anti-cancer treatment.

miRNA-520f Reverses Epithelial-to-Mesenchymal Transition by Targeting ADAM9 and TGFBR2

Reversing epithelial-to-mesenchymal transition (EMT) in cancer cells has been widely considered as an approach to combat cancer progression and therapeutic resistance, but a limited number of broadly comprehensive investigations of miRNAs involved in this process have been conducted. In this study, we screened a library of 1120 miRNA for their ability to transcriptionally activate the E-cadherin gene CDH1 in a promoter reporter assay as a measure of EMT reversal. By this approach, we defined miR-520f as a novel EMT-reversing miRNA. miR-520f expression was sufficient to restore endogenous levels of E-cadherin in cancer cell lines exhibiting strong or intermediate mesenchymal phenotypes. In parallel, miR-520f inhibited invasive behavior in multiple cancer cell systems and reduced metastasis in an experimental mouse model of lung metastasis. Mechanistically, miR-520f inhibited tumor cell invasion by directly targeting ADAM9, the TGFβ receptor TGFBR2 and the EMT inducers ZEB1, ZEB2, and the snail transcriptional repressor SNAI2, each crucial factors in mediating EMT. Collectively, our results show that miR-520f exerts anti-invasive and antimetastatic effects in vitro and in vivo, warranting further study in clinical settings. Cancer Res; 77(8); 2008-17. ©2017 AACR.

miR-30a radiosensitizes non-small cell lung cancer by targeting ATF1 that is involved in the phosphorylation of ATM

Increasing number of studies report that microRNAs play important roles in radiosensitization. miR-30a has been proved to perform many functions in the development and treatment of cancer, and it is downregulated in non-small cell lung cancer (NSCLC) tissues and cells. This study was conducted to understand if miR-30a plays a role in the radiosensitivity of NSCLC cells. Radiosensitivity was examed by colony survival assay and tumor volume changing in vitro and in vivo, respectively. Bioinformatic analysis and luciferase reporter assays were used to distinguish the candidate target of miR-30a. qRT-PCR and western blotting were carried out to detect the relative expression of mRNAs and proteins. Cell cycle and cell apoptosis were determined by flow cytometry. Our results illustrated miR-30a could increase the radiosensitivity of NSCLC, especially in A549 cell line. In vivo experiment also showed the potential radiosensitizing possibility of miR-30a. Further exploration validated that miR-30a was directly targeting activating transcription factor 1 (ATF1). In studying the ataxia-telangiectasia mutated (ATM) associated effects on cell radiosensitivity, we found that miR-30a could reduce radiation induced G2/M cell cycle arrest and may also affect radiation induced apoptosis. Together, our results demonstrated that miR-30a may modulate the radiosensitivity of NSCLC through reducing the function of ATF1 in phosphorylation of ATM and have potential therapeutic value.

Identification of MicroRNAs as Breast Cancer Prognosis Markers through the Cancer Genome Atlas

Breast cancer is the second-most common cancer and second-leading cause of cancer mortality in American women. The dysregulation of microRNAs (miRNAs) plays a key role in almost all cancers, including breast cancer. We comprehensively analyzed miRNA expression, global gene expression, and patient survival from the Cancer Genomes Atlas (TCGA) to identify clinically relevant miRNAs and their potential gene targets in breast tumors. In our analysis, we found that increased expression of 12 mature miRNAs-hsa-miR-320a, hsa-miR-361-5p, hsa-miR-103a-3p, hsa-miR-21-5p, hsa-miR-374b-5p, hsa-miR-140-3p, hsa-miR-25-3p, hsa-miR-651-5p, hsa-miR-200c-3p, hsa-miR-30a-5p, hsa-miR-30c-5p, and hsa-let-7i-5p -each predicted improved breast cancer survival. Of the 12 miRNAs, miR-320a, miR-361-5p, miR-21-5p, miR-103a-3p were selected for further analysis. By correlating global gene expression with miRNA expression and then employing miRNA target prediction analysis, we suggest that the four miRNAs may exert protective phenotypes by targeting breast oncogenes that contribute to patient survival. We propose that miR-320a targets the survival-associated genes RAD51, RRP1B, and TDG; miR-361-5p targets ARCN1; and miR-21-5p targets MSH2, RMND5A, STAG2, and UBE2D3. The results of our stringent bioinformatics approach for identifying clinically relevant miRNAs and their targets indicate that miR-320a, miR-361-5p, and miR-21-5p may contribute to breast cancer survival.

Propofol inhibits growth and invasion of pancreatic cancer cells through regulation of the miR-21/Slug signaling pathway

AIM

Propofol, an intravenous anesthetic agent, has been found to inhibit invasion and growth of pancreatic cancer cells in vitro. However, the mechanisms underlying these tumor-promoting phenotypes are not known. The microRNA miR-21 has been reported to be overexpressed in pancreatic cancer, and overexpression of miR-21 confers a poor prognosis to patients with pancreatic cancer. Further studies have identified the E-cadherin transcription repressor Slug as a direct target of miR-21. In this study, we assessed whether propofol inhibits invasion and growth of pancreatic cancer cells by regulation of miR-21/Slug signaling.

METHODS

PANC-1 pancreatic cancer cells were treated with different concentrations of propofol (1, 5 or 10 μg/mL) for 48 h, or 10 μg/mL propofol for 12, 24 or 36 h. Cell survival and apoptosis were detected by LDH release, BrdU cell proliferation and flow cytometry assays; cell invasion and migration were detected by transwell migration assays. miR-21 mimic (miR-21), Slug cDNA, PUMA siRNA and E-cadherin siRNA transfection was used to assess the signaling pathway in which propofol functions in PANC-1 cells. Protein and mRNA expression, respectively, were detected by western blotting and quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assays.

RESULTS

Propofol inhibited growth and invasion, and induced apoptosis, in a dose- and time-dependent manner in PANC-1 cells. Propofol inhibited miR-21 levels and decreased Slug expression, resulting in an increase in Slug-dependent PUMA and E-cadherin expression in PANC-1 cells. miR-21 overexpression or PUMA or E-cadherin silencing impaired propofol-induced cell apoptosis, growth and invasion. Re-expression of Slug attenuated the expression of PUMA and E-cadherin that was induced by propofol treatment, the reduction of growth and invasion, and the increase in cell apoptosis.

CONCLUSIONS

Propofol can effectively inhibit invasion and induce apoptosis of PANC-1 cells by regulating miR-21/Slug signals.