miR-335 Targets SIAH2 and Confers Sensitivity to Anti-Cancer Drugs by Increasing the Expression of HDAC3

We previously reported the role of histone deacetylase 3 (HDAC3) in response to anti-cancer drugs. The decreased expression of HDAC3 in anti-cancer drug-resistant cancer cell line is responsible for the resistance to anti-cancer drugs. In this study, we investigated molecular mechanisms associated with regulation of HDAC3 expression. MG132, an inhibitor of proteasomal degradation, induced the expression of HDAC3 in various anti-cancer drug-resistant cancer cell lines. Ubiquitination of HDAC3 was observed in various anti-cancer drug-resistant cancer cell lines. HDAC3 showed an interaction with SIAH2, an ubiquitin E3 ligase, that has increased expression in various anti-cancer drug-resistant cancer cell lines. miRNA array analysis showed the decreased expression of miR-335 in these cells. Targetscan analysis predicted the binding of miR-335 to the 3′-UTR of SIAH2. miR-335-mediated increased sensitivity to anti-cancer drugs was associated with its effect on HDAC3 and SIAH2 expression. miR-335 exerted apoptotic effects and inhibited ubiquitination of HDAC3 in anti-cancer drug-resistant cancer cell lines. miR-335 negatively regulated the invasion, migration, and growth rate of cancer cells. The mouse xenograft model showed that miR-335 negatively regulated the tumorigenic potential of cancer cells. The down-regulation of SIAH2 conferred sensitivity to anti-cancer drugs. The results of the study indicated that the miR-335/SIAH2/HDAC3 axis regulates the response to anti-cancer drugs.     

MicroRNA-155 is regulated by the transforming growth factor beta/Smad pathway and contributes to epithelial cell plasticity by targeting RhoA

Transforming growth factor β (TGF-β) signaling facilitates metastasis in advanced malignancy. While a number of protein-encoding genes are known to be involved in this process, information on the role of microRNAs (miRNAs) in TGF-β-induced cell migration and invasion is still limited. By hybridizing a 515-miRNA oligonucleotide-based microarray library, a total of 28 miRNAs were found to be significantly deregulated in TGF-β-treated normal murine mammary gland (NMuMG) epithelial cells but not Smad4 knockdown NMuMG cells. Among upregulated miRNAs, miR-155 was the most significantly elevated miRNA. TGF-β induces miR-155 expression and promoter activity through Smad4. The knockdown of miR-155 suppressed TGF-β-induced epithelial-mesenchymal transition (EMT) and tight junction dissolution, as well as cell migration and invasion. Further, the ectopic expression of miR-155 reduced RhoA protein and disrupted tight junction formation. Reintroducing RhoA cDNA without the 3′ untranslated region largely reversed the phenotype induced by miR-155 and TGF-β. In addition, elevated levels of miR-155 were frequently detected in invasive breast cancer tissues. These data suggest that miR-155 may play an important role in TGF-β-induced EMT and cell migration and invasion by targeting RhoA and indicate that it is a potential therapeutic target for breast cancer intervention.     

FOXO3a inhibits the EMT and metastasis of breast cancer by regulating TWIST-1 mediated miR-10b/CADM2 axis

BackgroundBreast cancer is the most common malignancy and has been considered as a leading cause of cancer death in women. Exploring the mechanism of breast cancer metastasis is extremely important for seeking novel therapeutic strategies and improving prognosis.MethodsClinical specimens and pathological characteristics were collected for evaluating the expression of forkhead box class O 3a (FOXO3a) and twist-related protein 1 (TWIST-1) in breast cancer tissues. CCK-8 assay was used to analyze cell proliferation. Cell invasion and migration were assessed by transwell assays. The expression of FOXO3a, TWIST-1, miR-10b, CADM2, FAK, phosphor-AKT and the epithelial-mesenchymal transition (EMT)-related protein (N-cadherin, E-cadherin and vimentin) were analyzed by RT-qPCR, immunohistochemical staining, immunofluorescence assay or western blot, respectively. Xenograft mouse models were used to analyze the role of the FOXO3a in breast cancer.ResultsFOXO3a was down-regulated and TWIST-1 was up-regulated in breast cancer tissues. Overexpression of FOXO3a or knockdown of TWIST-1 suppressed the proliferation, invasion, migration and EMT of breast cancer cells. Overexpression of TWIST-1 could reverse the effect of FOXO3a on the proliferation, invasion, migration and EMT of breast cancer. Moreover, FOXO3a suppressed the growth and metastasis of breast cancer by targeting TWIST1 in vivo.ConclusionFOXO3a inhibited the EMT and metastasis of breast cancer via TWIST-1/miR-10b/CADM2 axis.     

Comprehensive Analysis of MicroRNA (miRNA) Targets in Breast Cancer Cells

MicroRNAs (miRNAs) regulate mRNA stability and translation through the action of the RNAi-induced silencing complex. In this study, we systematically identified endogenous miRNA target genes by using AGO2 immunoprecipitation (AGO2-IP) and microarray analyses in two breast cancer cell lines, MCF7 and MDA-MB-231, representing luminal and basal-like breast cancer, respectively. The expression levels of ∼70% of the AGO2-IP mRNAs were increased by DROSHA or DICER1 knockdown. In addition, integrated analysis of miRNA expression profiles, mRNA-AGO2 interaction, and the 3′-UTR of mRNAs revealed that >60% of the AGO2-IP mRNAs were putative targets of the 50 most abundantly expressed miRNAs. Together, these results suggested that the majority of the AGO2-associated mRNAs were bona fide miRNA targets. Functional enrichment analysis uncovered that the AGO2-IP mRNAs were involved in regulation of cell cycle, apoptosis, adhesion/migration/invasion, stress responses (e.g. DNA damage and endoplasmic reticulum stress and hypoxia), and cell-cell communication (e.g. Notch and Ephrin signaling pathways). A role of miRNAs in regulating cell migration/invasion and stress response was further defined by examining the impact of DROSHA knockdown on cell behaviors. We demonstrated that DROSHA knockdown enhanced cell migration and invasion, whereas it sensitized cells to cell death induced by suspension culture, glucose depletion, and unfolding protein stress. Data from an orthotopic xenograft model showed that DROSHA knockdown resulted in reduced growth of primary tumors but enhanced lung metastasis. Taken together, these results suggest that miRNAs collectively function to promote survival of tumor cells under stress but suppress cell migration/invasion in breast cancer cells.     

MiR-487a Promotes TGF-β1-induced EMT,the Migration and Invasion of Breast Cancer Cells by Directly Targeting MAGI2

Tumor metastasis is a complex and multistep process and its exact molecular mechanisms remain unclear. We attempted to find novel microRNAs (miRNAs) contributing to the migration and invasion of breast cancer cells. In this study, we found that the expression of miR-487a was higher in MDA-MB-231breast cancer cells with high metastasis ability than MCF-7 breast cancer cells with low metastasis ability and the treatment with transforming growth factor β1 (TGF-β1) significantly increased the expression of miR-487a in MCF-7 and MDA-MB-231 breast cancer cells. Subsequently, we found that the transfection of miR-487a inhibitor significantly decreased the expression of vimentin, a mesenchymal marker, while increased the expression of E-cadherin, an epithelial marker, in both MCF-7 cells and MDA-MB-231 cells. Also, the inactivation of miR-487a inhibited the migration and invasion of breast cancer cells. Furthermore, our findings demonstrated that miR-487a directly targeted the MAGI2 involved in the stability of PTEN. The down-regulation of miR-487a increased the expression of p-PTEN and PTEN, and reduced the expression of p-AKT in both cell lines. In addition, the results showed that NF-kappaB (p65) significantly increased the miR-487a promoter activity and expression, and TGF-β1 induced the increased miR-487a promoter activity via p65 in MCF-7 cells and MDA-MB-231 cells. Moreover, we further confirmed the expression of miR-487a was positively correlated with the lymph nodes metastasis and negatively correlated with the expression of MAGI2 in human breast cancer tissues. Overall, our results suggested that miR-487a could promote the TGF-β1-induced EMT, the migration and invasion of breast cancer cells by directly targeting MAGI2.     

WISP1 aggravates cell metastatic potential by abrogating TGF-β-Smad2/3-dependent epithelial-to-mesenchymal transition in laryngeal squamous cell carcinoma

Laryngeal squamous cell cancer (LSCC) is a common carcinoma with high morbidity and mortality. Metastasis constitutes the major cause of death and poor prognosis among patients with LSCC. Recent evidence confirms critical function of Wnt1-inducible signaling protein 1 (WISP1) in several cancers. However, its contribution in LSCC metastasis remains unclear. Specimens of tumor tissues and adjacent normal mucosa were collected from patients with LSCC. The mRNA and protein levels were determined using quantitative real-time PCR and Western blot, respectively. RNA interference was applied to silence the expression of WISP1 and TGF-β, and recombinant adenovirus was used to overexpress WISP1 in human LSCC cell line TU212 cells. Cell invasion and migration were determined by transwell assay. High expression of WISP1 was observed in LSCC tissues, especially in those from metastatic groups. Ectopic expression of WISP1 enhanced invasion and migration of TU212 cells. On the contrary, WISP1 knockdown reduced numbers of invasive and migrated cells. Additionally, elevation of WISP1 depressed the expression of epithelial marker E-cadherin and increased levels of mesenchymal marker vimentin in TU212 cells, whereas WISP suppression yielded the opposite effects. Further analysis corroborated that WISP1 overexpression enhanced activation of TGF-β-Smad signaling by increasing expression of TGF-β1, p-Smad2, and p-Smad3, which was abrogated following WISP1 down-regulation. Moreover, TGF-β1 exposure facilitated LSCC cell invasion and migration. Notably, blockage of the TGF-β-Smad pathway by si-TGF-β overturned WISP-1-evoked epithelial-to-mesenchymal transition (EMT), and subsequent cell invasion and migration. These findings highlight the pro-metastatic function of WISP1 in LSCC by regulating cell invasion and migration via TGF-β-Smad-mediated EMT, supporting a promising invention target for LSCC therapy.     

SIAH2与P-ERK在乳腺癌中的表达及其临床意义

目的观察人乳腺细胞系及乳腺组织中SIAH2和P-ERK表达的变化,探讨乳腺癌中SIAH2与P-ERK的关联。方法应用免疫组织化学检测140例乳腺石蜡包埋组织中SIAH2和P-ERK的表达,Western blot检测人乳腺细胞系和23例乳腺浸润性导管癌及癌旁正常乳腺组织中SIAH2和P-ERK的蛋白表达情况,人乳腺癌细胞系表达SIAH2-siRNA后,P-ERK蛋白表达情况。结果乳腺癌中SIAH2和P-ERK阳性率与组织学分级相关(P<0.05),SIAH2和P-ERK呈正相关性。人乳腺癌细胞系以及乳腺癌组织中SIAH2和P-ERK蛋白表达量明显高于人乳腺正常上皮细胞系与癌旁正常乳腺组织中SIAH2和P-ERK蛋白表达量(P<0.05);表达SIAH2-siRNA的乳腺癌细胞系与对照组相比,P-ERK蛋白表达明显减少(P<0.05)。结论 SIAH2、P-ERK过表达与乳腺癌的组织学分级有关。在乳腺癌细胞系中抑制SIAH2表达后,P-ERK表达也减少,因此抑制SIAH2可以抑制ERK通路。     

Metadherin mediates lipopolysaccharide-induced migration and invasion of breast cancer cells

Background

Breast cancer is the most prevalent cancer in women worldwide and metastatic breast cancer has very poor prognosis. Inflammation has been implicated in migration and metastasis of breast cancer, although the exact molecular mechanism remains elusive.

Principal Findings

We show that the pro-inflammatory endotoxin Lipopolysaccharide (LPS) upregulates the expression of Metadherin (MTDH), a recently identified oncogene, in a number of breast cancer lines. Stable knockdown of MTDH by shRNA in human breast MDA-MB-231 cells abolishes LPS-induced cell migration and invasion as determined by several in vitro assays. In addition, knockdown of MTDH diminishes Nuclear Factor-kappa B (NF-κB) activation by LPS and inhibited LPS-induced IL-8 and MMP-9 production.

Conclusions

These results strongly suggest that MTDH is a pivotal molecule in inflammation-mediated tumor metastasis. Since NF-κB, IL-8 and MMP-9 play roles in LPS-induced invasion or metastasis, the mechanism of MTDH-promoted invasion and metastasis may be through the activation of NF-κB, IL-8 and MMP-9, also suggesting a role of MTDH in regulating both inflammatory responses and inflammation-associated tumor invasion. These findings indicate that MTDH is involved in inflammation-induced tumor progression, and support that MTDH targeting therapy may hold promising prospects in treating breast cancer.     

SMURF1 Plays a role in EGF-induced breast cancer cell migration and invasion

Epidermal growth factor (EGF) is a well-known growth factor that induces cancer cell migration and invasion. Previous studies have shown that SMAD ubiquitination regulatory factor 1 (SMURF1), an E3 ubiquitin ligase, regulates cell motility by inducing RhoA degradation. Therefore, we examined the role of SMURF1 in EGF-induced cell migration and invasion using MDA-MB-231 cells, a human breast cancer cell line. EGF increased SMURF1 expression at both the mRNA and protein levels. All ErbB family members were expressed in MDA-MB-231 cells and receptor tyrosine kinase inhibitors specific for the EGF receptor (EGFR) or ErbB2 blocked the EGF-mediated induction of SMURF1 expression. Within the signaling pathways examined, ERK1/2 and protein kinase C activity were required for EGF-induced SMURF1 expression. The overexpression of constitutively active MEK1 increased the SMURF1 to levels similar to those induced by EGF. SMURF1 induction by EGF treatment or by the overexpression of MEK1 or SMURF1 resulted in enhanced cell migration and invasion, whereas SMURF1 knockdown suppressed EGF- or MEK1-induced cell migration and invasion. EGF treatment or SMURF1 overexpression decreased the endogenous RhoA protein levels. The overexpression of constitutively active RhoA prevented EGF- or SMURF1-induced cell migration and invasion. These results suggest that EGFinduced SMURF1 plays a role in breast cancer cell migration and invasion through the downregulation of RhoA.     

Voltage-gated sodium channels and metastatic disease

Voltage-gated Na⁺ channels (VGSCs) are macromolecular protein complexes containing a pore-forming α subunit and smaller non-pore-forming β subunits. VGSCs are expressed in metastatic cells from a number of cancers. In these cells, Na⁺ current carried by α subunits enhances migration, invasion and metastasis in vivo. In contrast, the β subunits mediate cellular adhesion and process extension. The prevailing hypothesis is that VGSCs are upregulated in cancer, in general favoring an invasive/metastatic phenotype, although the mechanisms are still not fully clear. Expression of the Na_v1.5 α subunit associates with poor prognosis in clinical breast cancer specimens, suggesting that VGSCs may have utility as prognostic markers for cancer progression. Furthermore, repurposing existing VGSC-blocking therapeutic drugs may provide a new strategy to improve outcomes in patients suffering from metastatic disease, which is the major cause of cancer-related deaths, and for which there is currently no cure.     

Long non-coding RNA DIO3OS/let-7d/NF-κB2 axis regulates cells proliferation and metastasis of thyroid cancer cells

Due to the steadily rising morbidity and mortality, thyroid cancer remains the most commonly seen endocrine cancer. The present study attempted to investigate the mechanism from the perspective of long non-coding RNA (lncRNA) regulation. We identified 53 markedly increased lncRNAs in thyroid cancer samples according to TCGA data. Among them, high lncRNA DIO3OS expression was a risk factor for thyroid cancer patients’ poorer overall survival. DIO3OS showed to be considerably increased within thyroid cancer tissue samples and cells. Knocking down DIO3OS within thyroid carcinoma cells suppressed cancer cell viability, the capacity of DNA synthesis, cell invasion, as well as cell migration; besides, proliferating markers, ki-67 and PCNA, were decreased by DIO3OS knockdown. Cancer bioinformatics analysis suggested that NF-κB2 might be related to DIO3OS function in thyroid cancer carcinogenesis. NF-κB2 was positively correlated with DIO3OS, and DIO3OS knockdown decreased NF-κB2 protein levels. Knocking down NF-κB2 within thyroid carcinoma cells suppressed cancer cell viability, the capacity of DNA synthesis, cell invasion, cell migration, and the protein levels of proliferating markers. Let-7d directly targeted DIO3OS and NF-κB2; DIO3OS knockdown upregulated let-7d expression. The overexpression of let-7d suppressed cancer cell viability, the capacity of DNA synthesis, cell invasion, cell migration, as well as the protein levels of proliferating markers. Let-7d inhibition remarkably attenuated the functions of DIO3OS knockdown in NF-κB2 expression and thyroid cancer cell phenotype. In conclusion, DIO3OS/let-7d/NF-κB2 axis regulates the viability, DNA synthesis capacity, invasion, and migration of thyroid cancer cells. The clinical application of this axis needs further in vivo and clinical investigation.Electronic supplementary materialThe online version of this article (10.1007/s12079-020-00589-w) contains supplementary material, which is available to authorized users.     

Characterization of Spontaneous and TGF-β-Induced Cell Motility of Primary Human Normal and Neoplastic Mammary Cells In Vitro Using Novel Real-Time Technology

The clinical complications derived from metastatic disease are responsible for the majority of all breast cancer related deaths. Since cell migration and invasion are a prerequisite for metastasis their assessment in patient cancer cells in vitro may have prognostic value for the tumor''s metastatic capacity. We employed real-time cell analysis (RTCA) on the xCELLigence DP system to determine in vitro motility of patient-derived primary human breast cancer epithelial cells (HBCEC). Initially, the RTCA assay was validated using established human breast cancer cell lines with either an invasive (MDA-MB-231, MDA-MB-435s) or a non-invasive phenotype (MCF-7, MDA-MB-468), and primary NSCLC cells (Tu459). Previous standard assays of cell migration/invasion revealed that only MDA-MB-231, −435s, and Tu459 cells exhibited spontaneous and TGF-β1-stimulated migration and invasion through a Matrigel barrier. In the present study, the TGF-β1-stimulated activities could be blocked by SB431542, a potent kinase inhibitor of the TGF-β type I receptor ALK5. Application of the RTCA assay to patient-derived tumor cells showed that 4/4 primary HBCEC and primary NSCLC cells, but not normal human mammary epithelial cells (HMEC), displayed high spontaneous migratory and invasive activity which correlated with higher MMP-2 expression and uPA protein levels in HBCEC compared to HMEC. Upon treatment with TGF-β1, HBCEC exhibited morphologic and gene regulatory alterations indicative of epithelial-to-mesenchymal transition. However, exclusively the invasive but not the migratory activity of HBCEC was further enhanced by TGF-β1. This indicates the requirement for molecular, e.g. integrin interactions with Matrigel components in HBCEC in order to become responsive to pro-invasive TGF-β effects. Together, these results show for the first time that tumorigenic HBCEC but not normal HMEC possess a strong basal migratory as well as a basal and TGF-β1-inducible invasive potential. These findings qualify the RTCA assay as an in vitro migration/invasion testing system for patient-specific primary breast cancer cells.     

Sodium-Calcium Exchanger 1 Regulates Epithelial Cell Migration via Calcium-dependent Extracellular Signal-regulated Kinase Signaling

Na⁺/Ca²⁺ exchanger-1 (NCX1) is a major calcium extrusion mechanism in renal epithelial cells enabling the efflux of one Ca²⁺ ion and the influx of three Na⁺ ions. The gradient for this exchange activity is provided by Na,K-ATPase, a hetero-oligomer consisting of a catalytic α-subunit and a regulatory β-subunit (Na,K-β) that also functions as a motility and tumor suppressor. We showed earlier that mice with heart-specific ablation (KO) of Na,K-β had a specific reduction in NCX1 protein and were ouabain-insensitive. Here, we demonstrate that Na,K-β associates with NCX1 and regulates its localization to the cell surface. Madin-Darby canine kidney cells with Na,K-β knockdown have reduced NCX1 protein and function accompanied by 2.1-fold increase in free intracellular calcium and a corresponding increase in the rate of cell migration. Increased intracellular calcium up-regulated ERK1/2 via calmodulin-dependent activation of PI3K. Both myosin light chain kinase and Rho-associated kinase acted as mediators of ERK1/2-dependent migration. Restoring NCX1 expression in β-KD cells reduced migration rate and ERK1/2 activation, suggesting that NCX1 functions downstream of Na,K-β in regulating cell migration. In parallel, inhibition of NCX1 by KB-R7943 in Madin-Darby canine kidney cells, LLC-PK1, and human primary renal epithelial cells (HREpiC) increased ERK1/2 activation and cell migration. This increased migration was associated with high myosin light chain phosphorylation by PI3K/ERK-dependent mechanism in HREpiC cells. These data confirm the role of NCX1 activity in regulating renal epithelial cell migration.