Epithelial-mesenchymal transition in tumor metastasis

A novel inhibitor of MDM2 oncogene blocks metastasis of hepatocellular carcinoma and overcomes chemoresistance

Overexpression of the MDM2 oncogene and mutations in the p53 tumor suppressor commonly occur in hepatocellular carcinoma (HCC) and are associated with increased mortality due to this disease. Inhibiting MDM2 has been demonstrated to be a valid approach for the treatment of HCC. However, most of the MDM2 inhibitors evaluated to date have been designed to block the MDM2 and p53 binding, and have limited efficacy against tumors with mutant or deficient p53. In the present study, we developed a novel MDM2 inhibitor (termed SP141) that has direct effects on MDM2 and exerts anti-HCC activity independent of the p53 status of the cancer cells. We demonstrate that SP141 inhibits cell growth and prevents cell migration and invasion, independent of p53. Mechanistically, SP141 directly binds the MDM2 protein and promotes MDM2 degradation. The inhibition of MDM2 by SP141 also increases the sensitivity of HCC cells to sorafenib. In addition, in orthotopic and patient-derived xenograft models, SP141 inhibits MDM2 expression and suppresses tumor growth and metastasis, without any host toxicity. Furthermore, the inhibition of MDM2 by SP141 is essential for its anti-HCC activities. These results provide support for the further development of SP141 as a lead candidate for the treatment of HCC.

HnRNP-F regulates EMT in bladder cancer by mediating the stabilization of Snail1 mRNA by binding to its 3' UTR

Background

Heterogeneous nuclear ribonucleoprotein F (hnRNP-F) has been implicated in multiple cancers, suggesting its role in tumourigenesis, but the potential oncogenic role and mechanism of hnRNP-F in bladder cancer (BC) remain incompletely understood.

Methods

HnRNP-F was identified by proteomic methods. A correlation of hnRNP-F expression with prognosis was analysed in 103 BC patients. Then, we applied in vitro and in vivo methods to reveal the behaviours of hnRNP-F in BC tumourigenesis. Furthermore, the interaction between hnRNP-F and Snail1 mRNA was examined by RNA immunoprecipitation (RIP), and Snail1 mRNA stability was measured after treatment with actinomycin D. Finally, the binding domain between hnRNP-F and Snail1 mRNA was verified by constructing Snail1 mRNA truncations and mutants.

Finding

HnRNP-F is significantly upregulated in BC tissue, and its increased expression is associated with a poor prognosis in BC patients. HnRNP-F is necessary for tumour growth, inducing epithelial-mesenchymal transition (EMT) and metastasis in BC. The changes in Snail1 expression were positively correlated with hnRNP-F at both the mRNA and protein levels when hnRNP-F was silenced or enhanced, suggesting that Snail1 is likely a downstream target of hnRNP-F that mediates its effects on enhancing invasion, metastasis and EMT in BC. The overexpression of hnRNP-F caused an increase in the stability of Snail1 mRNA. Our RNA chip analysis revealed that hnRNP-F could combine with Snail1 mRNA, and we further demonstrated that hnRNP-F could directly bind to the 3′ untranslated region (3′ UTR) of Snail1 mRNA to enhance its stability.

Interpretation

Our findings suggest that hnRNP-F mediates the stabilization of Snail1 mRNA by binding to its 3′ UTR, subsequently regulating EMT.

Stromal fibroblast-derived MFAP5 promotes the invasion and migration of breast cancer cells via Notch1/slug signaling

BACKGROUND

The tumor microenvironment (TME) regulates tumor progression, and cancer-associated fibroblasts (CAFs) are the primary stromal components of the TME, with the potential to drive tumor metastasis via the secretion of paracrine factors, but the specific mechanisms driving this process have not been defined.

METHODS

Proteins secreted from CAFs and normal fibroblasts (NFs) were analyzed via proteomic analysis (fold change > 2, p < 0.05) to identify tumor-promoting proteins secreted by CAFs.

RESULTS

Proteomic analysis revealed that microfibrillar-associated protein 5 (MFAP5) is preferentially expressed and secreted by CAFs relative to NFs, which was confirmed by Western blotting and RT-qPCR. Transwell and wound healing assays confirmed that MFAP5 is secreted by CAFs, and drives the invasion and migration of MCF7 breast cancer cells. We further found that in MCF7 cells MFAP5 promoted epithelial-mesenchymal transition, activating Notch1 signaling and consequently upregulating NICD1 and slug. When Notch1 was knocked down in MCF7 cells, the ability of MFAP5 to promote invasion and migration decreased.

CONCLUSION

CAFs promote cancer cells invasion and migration via MFAP5 secretion and activation of the Notch1/slug signaling. These data highlight this pathway as a therapeutic target to disrupt tumor progression through the interference of CAF-tumor crosstalk.

miR-27b-3p/MARCH7 regulates invasion and metastasis of endometrial cancer cells through Snail-mediated pathway

Ubiquitin E3 ligase membrane-associated RING-CH-type finger 7 (MARCH7), also known as axotrophin, was originally identified in mouse embryonic stem cells. MARCH7 is involved in T-cell proliferation, neuronal development, and the immune system. However, its role in endometrial cancer (EC) remains unclear. This study aimed to investigate the role of MARCH7 in EC. Quantitative polymerase chain reaction, immunohistochemistry, and western blot analysis were used to examine the expression of MARCH7, E-cadherin, Snail, and Vimentin in EC cell lines or clinical specimens. The role of MARCH7 in maintaining EC cell malignant phenotype was determined by transwell assay and using xenograft tumor model. Dual-luciferase reporter gene assay was performed to determine whether MARCH7 is an authentic target of miR-27b-3p. Our data showed that the expression level of MARCH7 in EC tissues was higher than that in normal endometrium tissues. The level of MARCH7 was positively associated with that of Snail and Vimentin, clinical stage, and histological grade, while negatively associated with that of E-cadherin. Knockdown of MARCH7 inhibited the invasion and metastasis of EC cells in vitro and in vivo. The opposite effect was observed after overexpressing MARCH7. MARCH7 promoted invasion and metastasis of EC cells via the Snail-mediated pathway. Furthermore, MARCH7 was demonstrated to be an authentic target of miR-27b-3p, and miR-27b-3p decreased the stimulus effect induced by MARCH7. These data indicate that MARCH7 may be an oncogenic factor and a therapeutic target for EC. miR-27b-3p/MARCH7 may also regulate EC cell invasion and metastasis via the Snail-mediated pathway.

DCLK1 Plays a Metastatic-Promoting Role in Human Breast Cancer Cells

Background

Doublecortin-like kinase 1 (DCLK1) has been universally identified as a cancer stem cell (CSC) marker and is found to be overexpressed in many types of cancers including breast cancer. However, there is little data regarding the functional role of DCLK1 in breast cancer metastasis. In the present study, we sought to investigate whether and how DCLK1 plays a metastatic-promoting role in human breast cancer cells.

Methods

We used Crispr/Cas9 technology to knock out DCLK1 in breast cancer cell line BT474, which basically possesses DCLK1 at a higher level, and stably overexpressed DCLK1 in another breast cancer cell line, T47D, that basically expresses DCLK1 at a lower level. We further analyzed the alterations of metastatic characteristics and the underlying mechanisms in these cells.

Results

It was shown that, compared with the corresponding control cells, DCLK1 overexpression led to an increase in metastatic behaviors including enhanced migration and invasion of T47D cells. By contrast, forced depletion of DCLK1 drastically inhibited these metastatic characteristics in BT474 cells. Mechanistically, the epithelial-mesenchymal transition (EMT) program, which is critical for cancer metastasis, was prominently activated in DCLK1-overexpressing cancer cells, evidenced by a decrease in an epithelial marker ZO-1 and an enhancement in several mesenchymal markers including ZEB1 and Vimentin. In addition, DCLK1 overexpression induced the ERK MAPK pathway, which resultantly enhanced the expression of MT1-MMP that is also involved in cancer metastasis. Knockout of DCLK1 could reverse these events, further supporting a metastatic-promoting role for DCLK1.

Conclusions

Collectively, our data suggested that DCLK1 overexpression may be responsible for the increased metastatic features in breast cancer cells. Targeting DCLK1 may become a therapeutic option for breast cancer metastasis.

The emerging links between chromosomal instability (CIN), metastasis, inflammation and tumour immunity

Many cancers possess an incorrect number of chromosomes, a state described as aneuploidy. Aneuploidy is often caused by Chromosomal Instability (CIN), a process of continuous chromosome mis-segregation. CIN is believed to endow tumours with enhanced evolutionary capabilities due to increased intratumour heterogeneity, and facilitating adaptive resistance to therapies. Recently, however, additional consequences and associations with CIN have been revealed, prompting the need to understand this universal hallmark of cancer in a multifaceted context. This review is focused on the investigation of possible links between CIN, metastasis and the host immune system in cancer development and treatment. We specifically focus on these links since most cancer deaths are due to the consequences of metastasis, and immunotherapy is a rapidly expanding novel avenue of cancer therapy.

Metastasis Organotropism: Redefining the Congenial Soil

Metastasis is the most devastating stage of cancer progression and causes the majority of cancer-related deaths. Clinical observations suggest that most cancers metastasize to specific organs, a process known as "organotropism." Elucidating the underlying mechanisms may help identify targets and treatment strategies to benefit patients. This review summarizes recent findings on tumor-intrinsic properties and their interaction with unique features of host organs, which together determine organ-specific metastatic behaviors. Emerging insights related to the roles of metabolic changes, the immune landscapes of target organs, and variation in epithelial-mesenchymal transitions open avenues for future studies of metastasis organotropism.

Beyond a chemopreventive reagent, aspirin is a master regulator of the hallmarks of cancer

PURPOSE

Aspirin, one of the most commonly used nonsteroidal anti-inflammatory drugs (NAIDS), not only shows cancer chemoprevention effects but also improves cancer therapeutic effects when combined with other therapies. Studies that focus on aspirin regulation of the hallmarks of cancer and the associated molecular mechanisms facilitate a more thorough understanding of aspirin in mediating chemoprevention and may supply additional information for the development of novel cancer therapeutic agents.

METHODS

The relevant literatures from PubMed have been reviewed in this article.

RESULTS

Current studies have revealed that aspirin regulates almost all the hallmarks of cancer. Within tumor tissue, aspirin suppresses the bioactivities of cancer cells themselves and deteriorates the tumor microenvironment that supports cancer progression. In addition to tumor tissues, blocking of platelet activation also contributes to the ability of aspirin to inhibit cancer progression. In terms of the molecular mechanism, aspirin targets oncogenes and cancer-related signaling pathways and activates certain tumor suppressors.

CONCLUSION

Beyond a chemopreventive agent, aspirin is a master regulator of the hallmarks of cancer.

Metastasis inhibition in breast cancer by targeting cancer cell extravasation

The spread of cells from primary tumors toward distant tissues and organs, also known as metastasis, is responsible for most cancer-associated deaths. The metastasis cascade comprises a series of events, characterized by the displacement of tumor cells (TCs) from the primary tumor to distant organs by traveling through the bloodstream, and their subsequent colonization. The first step in metastasis involves loss of cell-cell and cell-matrix adhesions, increased invasiveness and migratory abilities, leading to intravasation of TCs into the blood or lymphatic vessels. Stationary TCs must undergo the process of epithelial-mesenchymal transition in order to achieve this migratory and invasive phenotype. Circulating tumor cells that have survived in the circulation and left the blood or lymphatic vessels will reach distant sites where they may stay dormant for many years or grow to form secondary tumors. To do this, cells need to go through the mesenchymal-epithelial transition to revert the phenotype in order to regain epithelial cell-to-cell junctions, grow and become a clinically relevant and detectable tumor mass. This work will review the main steps of the metastatic cascade and describe some strategies to inhibit metastasis by reducing cancer cell extravasation presenting recent studies in the context of breast cancer.

Duodenal obstruction induced by retroperitoneal progression of bladder cancer: a report of two cases

Bladder cancer usually forms a papillary structure. Progression along the cavity or membranous structures surrounding the bladder, rectum, or retroperitoneum without formation of a discrete mass is rare. We here present two patients with duodenal obstruction caused by retroperitoneal progression of bladder cancer, in both of whom computed tomography revealed bladder and rectal wall thickening with a malignant target sign, thickened mesorectal fascia with abnormal tissue stranding, and increased perirectal fat density. Both cancers progressed despite treatment, as indicated by faint abnormal tissue stranding and increased retroperitoneal fat density along the retromesenteric plane from the pelvis to the duodenum. Subsequently, both patients developed obstruction in the horizontal portion of the duodenum, still without formation of a mass lesion. These two patients highlight the challenges associated with retroperitoneal invasion by bladder cancer in the absence of a mass lesion and underscore the importance of considering cancer progression in patients with bowel obstruction, even when there is no obvious mass lesion and/or only minor retroperitoneal findings. Progression along the retromesenteric plane may be the key pathway via which progressive bladder cancer results in duodenal obstruction without or with a minor mass lesion.

Long non-coding RNA Taurine upregulated gene 1 promotes osteosarcoma cell metastasis by mediating HIF-1α via miR-143-5p

Early aggressive metastasis of osteosarcoma (OS) leads to rapid progression and poor prognosis. Increasing evidence has demonstrated that long non-coding RNAs (lncRNAs) could serve as crucial regulators to modulate tumour metastasis. In this study, we reported the critical role of lncRNA TUG1 in determining OS metastasis. TUG1 was significantly upregulated in OS tissues and associated with tumour size, distant metastasis, TNM stage, and overall and recurrence-free survival, which further indicated poor prognosis. Furthermore, CAFs-derived TGF-β could upregulate TUG1 expression, and the crosstalk between CAFs and OS cells induced TUG1 to promote OS cell metastasis. Dysregulated TUG1 expression could act as an miRNA “sponge” to competitively protect the HIF-1α mRNA 3′UTR from miR-143-5p. Our study emphasised the effects of TUG1 in OS and demonstrated a novel axis by which TUG1 regulated OS cell metastasis, angiogenesis, and proliferation in vivo and in vitro. Collectively, TUG1 might be a prognostic indicator for OS and could be a therapeutic target for OS.

Physciosporin suppresses the proliferation, motility and tumourigenesis of colorectal cancer cells

BACKGROUND

Lichens, which represent symbiotic associations of fungi and algae, are potential sources of numerous natural products. Physciosporin (PHY) is a potent secondary metabolite found in lichens and was recently reported to inhibit the motility of lung cancer cells via novel mechanisms.

PURPOSE

The present study investigated the anticancer potential of PHY on colorectal cancer (CRC) cells.

METHODS

PHY was isolated from lichen extract by preparative TLC. The effect of PHY on cell viability, motility and tumourigenicity was elucidated by MTT assay, hoechst staining, flow cytometric analysis, transwell invasion and migration assay, soft agar colony formation assay, Western blotting, qRT-PCR and PCR array in vitro as well as tumorigenicity study in vivo.

RESULTS

PHY decreased the viability of various CRC cell lines (Caco2, CT26, DLD1, HCT116 and SW620). Moreover, PHY elicited cytotoxic effects by inducing apoptosis at toxic concentrations. At non-toxic concentrations, PHY dose-dependently suppressed the invasion, migration and colony formation of CRC cells. PHY inhibited the motility of CRC cells by suppressing epithelial-mesenchymal transition and downregulating actin-based motility markers. In addition, PHY downregulated β-catenin and its downstream target genes cyclin-D1 and c-Myc. Moreover, PHY modulated KAI1 C-terminal-interacting tetraspanin and KAI1 expression, and downregulated the downstream transcription factors c-jun and c-fos. Finally, PHY administration showed considerable bioavailability and effectively decreased the growth of CRC xenografts in mice without causing toxicity.

CONCLUSION

PHY suppresses the growth and motility of CRC cells via novel mechanisms.

Traditional Chinese medicine formulation Yanggan Jiedu Sanjie inhibits TGF-β1-induced epithelial-mesenchymal transition and metastatic potential in human hepatocarcinoma Bel-7402 cells

BACKGROUND

Epithelial-mesenchymal transition (EMT) is a vital process in cancer progression and metastasis. Yanggan Jiedu Sanjie (YGJDSJ) is Traditional Chinese Medicine formulation for liver cancer treatment. In the present study, we evaluated the effects of YGJDSJ on TGF-β1-induced EMT in hepatocellular carcinoma Bel-7402 cells.

METHODS

Bel-7402 cells were treated with TGF-β1 and YGJDSJ. EMT was identified by morphological changes and expression of marker proteins. Cell morphology was observed under a microscope. Protein expression and phosphorylation was detected by western blotting. Cell migration was measured by the scratch assay. Cell adhesion and invasion was detected by a commercial kit.

RESULTS

YGJDSJ reversed TGF-β1-induced morphological changes, as well as the expression of the EMT markers E-cadherin and N-cadherin in Bel-7402 cells. YGJDSJ also inhibited TGF-β1 up-regulated Smad3 phosphorylation and Snail expression in Bel-7402 cells. Moreover, YGJDSJ inhibited TGF-β1-induced cell adhesion, migration and invasion in Bel-7402 cells.

CONCLUSIONS

YGJDSJ inhibited TGF-β1-induced EMT and mediated metastatic potential of Bel-7402 cells, which may be related to down-regulation of Smad3 phosphorylation and Snail expression. The present study provides a new basis for application of this herbal formula for prevention of liver cancer metastasis.

Application of temporary agglomeration of chitosan-coated nanoparticles for the treatment of lung metastasis of melanoma

Temporary association of chitosan (CS)-coated nanoparticles (NPs) including phloretin (Phl) in the blood stream can be applied to treat lung metastasis of melanoma. Phl was entrapped in poly(d,l-lactide-co-glycolide) (PLGA) NPs as an anticancer agent, whereas CS was decorated onto the outer surfaces of the Phl-loaded PLGA NPs (PLGA/Phl NPs). CS-coated PLGA/Phl NPs (CS-PLGA/Phl NPs) with mean hydrodynamic sizes of 342 nm, spherical shapes, unimodal size distribution, positive zeta potentials, and drug encapsulation efficiency larger than 90% were prepared. The presence of the CS layers in the outer surfaces of the CS-PLGA/Phl NPs was elucidated by X-ray photoelectron spectroscopy. Upon blending of the CS-PLGA/Phl NPs with serum albumin, microscale agglomerates formed and easily dissociated into individual NPs by applying external forces. A sustained Phl release from NPs and similar antiproliferation potential of the CS-PLGA/Phl NPs to that of Phl in melanoma (B16F10) cells were observed. After multiple dosing of developed NPs in mouse models with lung metastasis of melanoma, the CS-PLGA/Phl NPs group exhibited significantly lower lung weight and number of metastasis foci than the PLGA/Phl NPs group (p < 0.05). These results suggest that the transient transformation of NPs into microscale aggregates and their facile dissociation into individual NPs can be efficiently and safely applied for the treatment of lung metastasis of melanoma.

Insufficient radiofrequency ablation promotes the metastasis of residual hepatocellular carcinoma cells via upregulating flotillin proteins

Purpose

Radiofrequency ablation (RFA) therapy has proven to be effective and feasible for early-stage hepatocellular carcinoma (HCC); however, rapid progression of residual tumor cells after RFA has been confirmed, but the molecular mechanisms of this phenomenon are poorly understood. This study evaluated the effect of the lipid raft proteins known as flotillins on the invasive and metastatic potential of residual HCC.

Methods

The human HCC cell line HCCLM3 was used to establish insufficient RFA models in vivo and in vitro. Changes in cellular morphology, soft agar colony formation, motility, metastasis, and epithelial–mesenchymal transition (EMT) markers after insufficient RFA intervention in vitro and in vivo were detected by real-time PCR, western blotting, immunohistochemistry and transwell assays.

Results

The results showed that flotillin-1 and flotillin-2 expression were upregulated in HCCLM3 cells following 45 °C heat treatment and in residual HCCLM3 xenografts cells after insufficient RFA. Knocking down flotillin-1 or flotillin-2 in HCCLM3 cells by shRNA significantly lowered insufficient RFA-induced tumor growth, EMT changes, and metastasis in vitro and in vivo. Furthermore, mechanism studies indicated that flotillins altered the EMT status and metastatic potential of heat-treated HCCLM3 cells by activating the Akt/Wnt/β-catenin signaling pathway.

Conclusions

Our findings present new evidence that flotillins play a key role in the aggressive behaviors of residual cancer cells after insufficient RFA and provide new insights into the regulatory mechanism of Wnt/β-catenin signaling.

Electronic supplementary material

The online version of this article (10.1007/s00432-019-02852-z) contains supplementary material, which is available to authorized users.

Knockdown of AGGF1 inhibits the invasion and migration of gastric cancer via epithelial-mesenchymal transition through Wnt/β-catenin pathway

Background

Angiogenic factor with G-patch and FHA domain 1 (AGGF1), as a newly identified human angiogenic factor, is overexpressed in some types of malignant tumors and closely associated with patient’s prognosis. However, the mechanisms involved in the regulation of AGGF1 in gastric cancer (GC) still remain unclear.

Methods

In this study, AGGF1 level in GC tissues and cell lines was analyzed by western blot and quantitative real-time polymerase chain reaction (qRT-PCR). After knockdown of AGGF expression by RNA interference in GC cell lines MKN-45 and MGC-803, wound healing and transwell assays were conducted to examine the effects of AGGF1 on migration and invasion. Tumor growth was assessed in a mouse xenograft model in vivo. Furthermore, expression levels of epithelial–mesenchymal transition (EMT) biomarkers and involvement of the Wnt/β-catenin pathway were detected by western blot and qRT-PCR.

Results

Compared to those in normal groups, the protein and mRNA of AGGF1 expression levels were significantly higher both in GC tissues and cell lines (all P < 0.05). Knockdown of AGGF1 dramatically inhibited the invasion and migration of MKN-45 and MGC-803 cells (all P < 0.01) in vitro, and suppressed the tumor growth of nude mice xenograft model in vivo. Western blot revealed alterations in EMT biomarkers, suggesting the role of AGGF1 in EMT. Moreover, we found that downregulated expression of AGGF1 attenuated Wnt/β-catenin related protein expression.

Conclusions

Collectively, knockdown of AGGF1 inhibits the invasion and migration of gastric cancer via epithelial–mesenchymal transition through Wnt/β-catenin pathway.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0765-6) contains supplementary material, which is available to authorized users.

Salvianolic Acids: Potential Source of Natural Drugs for the Treatment of Fibrosis Disease and Cancer

Salvianolic acids, the most effective and abundant compounds extracted from Salvia miltiorrhiza (Danshen), are well known for its good anti-oxidative activity. Danshen has been extensively used as a traditional medicine to treat cardiovascular-related diseases in China and other Asian countries for hundreds of years. Recently, more and more studies have demonstrated that salvianolic acids also have a good effect on the alleviation of fibrosis disease and the treatment of cancer. In vivo and in vitro experiments have demonstrated that salvianolic acids can modulate signal transduction within fibroblasts and cancer cells. It is discovered that the cancer treatment of salvianolic acids is not only because salvianolic acids promote the apoptosis of cancer cells, but also due to the inhibition of cancer-associated epithelial-mesenchymal transition processes. In this article, we review a variety of studies focusing on the comprehensive roles of salvianolic acids in the treatment of fibrosis disease and cancer. These perspectives on the therapeutic potential of salvianolic acids highlight the importance of these compounds, which could be the novel and attractive drugs for fibrosis disease and cancer.

Circular RNA circNRIP1 acts as a microRNA-149-5p sponge to promote gastric cancer progression via the AKT1/mTOR pathway

BACKGROUND

CircRNA has emerged as a new non-coding RNA that plays crucial roles in tumour initiation and development. 'MiRNA sponge' is the most reported role played by circRNAs in many tumours. The AKT/mTOR axis is a classic signalling pathway in cancers that sustains energy homeostasis through energy production activities, such as the Warburg effect, and blocks catabolic activities, such as autophagy. Additionally, the AKT/mTOR axis exerts a positive effect on EMT, which promotes tumour metastasis.

METHODS

We detected higher circNRIP1 expression in gastric cancer by performing RNA-seq analysis. We verified the tumour promotor role of circNRIP1 in gastric cancer cells through a series of biological function assays. We then used a pull-down assay and dual-luciferase reporter assay to identify the downstream miR-149-5p of circNRIP1. Western blot analysis and immunofluorescence assays were performed to demonstrate that the circNRIP1-miR-149-5p-AKT1/mTOR axis is responsible for the altered metabolism in GC cells and promotes GC development. We then adopted a co-culture system to trace circNRIP1 transmission via exosomal communication and RIP experiments to determine that quaking regulates circNRIP1 expression. Finally, we confirmed the tumour suppressor role of microRNA-133a-3p in vivo in PDX mouse models.

RESULTS

We discovered that knockdown of circNRIP1 successfully blocked proliferation, migration, invasion and the expression level of AKT1 in GC cells. MiR-149-5p inhibition phenocopied the overexpression of circNRIP1 in GC cells, and overexpression of miR-149-5p blocked the malignant behaviours of circNRIP1. Moreover, it was proven that circNRIP1 can be transmitted by exosomal communication between GC cells, and exosomal circNRIP1 promoted tumour metastasis in vivo. We also demonstrated that quaking can promote circNRIP1 transcription. In the final step, the tumour promotor role of circNRIP1 was verified in PDX models.

CONCLUSIONS

We proved that circNRIP1 sponges miR-149-5p to affect the expression level of AKT1 and eventually acts as a tumour promotor in GC.

MicroRNA-625 inhibits cell invasion and epithelial-mesenchymal transition by targeting SOX4 in laryngeal squamous cell carcinoma

INTRODUCTION

Laryngeal squamous cell carcinoma (LSCC) is a highly aggressive malignant cancer, but the molecular mechanisms underlying its development and progression remain largely elusive. The purpose of the present study is to investigate the expression profile and functional role of microRNA-625 (miR-625) in LSCC.

MATERIALS AND METHODS

LSCC tissues and adjacent normal tissues were collected from 86 LSCC patients. The expression levels of miR-625 and SOX4 mRNA in tissues and cells were detected by RT-qPCR analysis. The expression levels of SOX4 and EMT-related proteins were detected by western blot analysis. In vitro cell proliferation, migration, and invasion were detected by MTT assay, colony formation assay, wound healing assay, and transwell invasion assay, respectively. Dual-luciferase reporter assay was performed to verify the binding relationship between miR-625 and the 3'-UTR of SOX4.

RESULTS

The results demonstrated that miR-625 is significantly down-regulated in clinical LSCC tissues, and its low expression may be closely associated with unfavorable clinicopathological characteristics of LSCC patients. Overexpression of miR-625 significantly suppressed the proliferation, migration, invasion, and EMT of LSCC cells. Furthermore, SOX4 was validated as a direct target of miR-625 in LSCC cells, and rescue experiments suggested that restoration of SOX4 blocked the tumor suppressive role of miR-625 in LSCC cells.

CONCLUSIONS

Taken together, these findings highlighted a critical role of miR-625 in the pathogenesis of LSCC, and restoration of miR-625 could be considered as a potential therapeutic strategy against this fatal disease.

The prognostic and therapeutic implications of circulating tumor cell phenotype detection based on epithelial-mesenchymal transition markers in the first-line chemotherapy of HER2-negative metastatic breast cancer

Background

Epithelial–mesenchymal transition (EMT) is implicated in the metastatic process and presents a challenge to epithelial cell adhesion molecule-based detection of circulating tumor cells (CTCs), which have been demonstrated to be a prognostic indicator in metastatic breast cancer. Although evidence has indicated that heterogeneity of CTCs based on EMT markers is associated with disease progression, no standard recommendations have been established for clinical practice. This study aimed to evaluate the prognostic significance of dynamic CTC detection based on EMT for metastatic breast cancer patients.

Methods

We enrolled 108 human epidermal growth factor receptor 2-negative metastatic breast cancer patients from the prospective phase III CAMELLIA study and applied the CanPatrol CTC enrichment technique to identify CTC phenotypes (including epithelial CTCs, biphenotypic epithelial/mesenchymal CTCs, and mesenchymal CTCs) in peripheral blood samples. Receiver operating characteristic curve analyses of total CTC count and the proportion of mesenchymal CTCs for predicting the 1-year progression-free survival (PFS) rate were conducted to determine the optimal cut-off values, and Kaplan–Meier analysis and Cox proportional hazards regression analysis were performed to investigate the prognostic value of the cut-off values of both total CTC count and the proportion of mesenchymal CTCs in combination.

Results

For predicting the 1-year PFS rate, the optimal cut-off value of total CTC count was 9.5 (Area under the curve [AUC] = 0.538, 95% confidence interval [CI] = 0.418–0.657), and that of the proportion of mesenchymal CTCs was 10.7% (AUC = 0.581, 95% CI = 0.463–0.699). We used the two cut-off values in combination to forecast PFS in which the total CTC count was equaled to or exceeded 10/5 mL with the proportion of mesenchymal CTCs surpassed 10.7%. Patients who met the combined criteria had significantly shorter median PFS than did those who did not meet the criteria (6.2 vs. 9.9 months, P =0.010). A nomogram was constructed based on the criteria and significant clinicopathological characteristics with a C-index of 0.613 (P = 0.010).

Conclusions

The criteria, which combine the total CTC count and the proportion of mesenchymal CTCs, may be used to monitor therapeutic resistance and predict prognosis in patients with metastatic breast cancer.

Trial registrationClinicalTrials.gov. NCT01917279. Registered on 19 July 2013, https://clinicaltrials.gov/ct2/show/NCT01917279?term=NCT01917279&rank=1.

SATB1 promotes epithelial-mesenchymal transition via Notch signaling pathway in colorectal cancer

Epithelial-mesenchymal transition (EMT) is essential for initiation of colorectal cancer (CRC) metastasis, but the diver proteins of EMT remain unclear. Special AT-rich sequence-binding protein 1 (SATB1) was found to be overexpressed in CRC cell lines, and its expression level was positively correlated with CRC progression. Strikingly, EMT process was regulated by SATB1, as SATB1 overexpression upregulated E-cadherin and SATB1 knockdown inhibited N-cadherin cell models. Mechanistically, SATB1 promoted EMT-mediated CRC metastasis via activation of Notch signaling pathway. Taken together, SATB1 plays a vital role in CRC metastasis and may act as a novel prognostic biomarker and a promising therapeutic target for CRC.

Mesenchymal stem cell-derived extracellular vesicles may promote breast cancer cell dormancy

Disseminated breast cancer cells have the capacity to metastasise to the bone marrow and reside in a dormant state within the mesenchymal stem cell niche. Research has focussed on paracrine signalling factors, such as soluble proteins, within the microenvironment. However, it is now clear extracellular vesicles secreted by resident mesenchymal stem cells into this microenvironment also play a key role in the initiation of dormancy. Dormancy encourages reduced cell proliferation and migration, while upregulating cell adhesion, thus retaining the cancer cells within the bone marrow microenvironment. Here, MCF7 breast cancer cells were treated with mesenchymal stem cell-derived extracellular vesicles, resulting in reduced migration in two-dimensional and three-dimensional culture, with reduced cell proliferation and enhanced adhesion, collectively supporting cancer cell dormancy.

Elevated FAM3C promotes cell epithelial- mesenchymal transition and cell migration in gastric cancer

Background

Tumor metastasis is an important factor in treatment failure for advanced gastric cancer. Family with sequence similarity 3 member C (FAM3C) is known to play a critical role in inducing epithelial–mesenchymal transition in several cancer types, while its role in gastric cancer is unidentified. The aim of this study was to investigate the role of FAM3C in gastric cancer and provide new information on the receptor tyrosine-kinase pathway and cytokine-based therapies.

Methods

FAM3C expression was tested in human gastric cancer tissue and adjacent normal mucosa, and the prognostic effect of FAM3C was analyzed in data from the Cancer Genome Atlas (TCGA). The role of FAM3C in gastric cancer proliferation and metastasis was investigated in vitro and in vivo. Western blot analysis and immunofluorescence were used to detect the underlying mechanisms.

Results

FAM3C expression was increased in gastric cancer tissue and showed cytoplasmic distribution. Gastric cancer patients with FAM3C overexpression had significantly worse prognoses based on TCGA data. In the gastric cancer cell lines MKN45 and AGS, knockdown of FAM3C dramatically attenuated cell migration, but had almost no influence on proliferation, while exogenous FAM3C promoted cell migration in a cell line with low FAM3C expression. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment of TCGA data showed that FAM3C was mainly associated with genes involved in focal adhesion, extracellular matrix–receptor interactions and the PI3K–Akt signaling pathway. Knockdown of FAM3C in gastric cancer cell lines significantly suppressed epithelial–mesenchymal transition, as demonstrated by increased expression of E-cadherin and decreased expression of Snail and Slug. Furthermore, knockdown of FAM3C strongly suppressed activation of the PI3K–Akt signaling pathway. Finally, we confirmed that FAM3C knockdown significantly decreased metastatic lesions in vivo.

Conclusion

Our study demonstrated that FAM3C can promote gastric cancer metastasis both in vitro and in vivo. FAM3C should be taken into consideration for gastric cancer treatments involving inhibition of the ligands and downstream pathways of receptor tyrosine kinases.

Antitumor activity of the novel HDAC inhibitor CUDC-101 combined with gemcitabine in pancreatic cancer

Histone deacetylase (HDAC) is overexpressed in multiple cancers including pancreatic cancer (PC). However, the effects of histone deacetylase inhibitor (HDACi) on apoptosis and epithelial-mesenchymal transition (EMT) differ in various cancers. In this study, we aimed to investigate the anti-tumor effects of a novel multitargets HDACi, CUDC-101, combined with gemcitabine in PC cell lines. In vitro, we found that Co-treatment with CUDC-101 and gemcitabine results in greater levels of apoptosis and significantly inhibited cell proliferation on PC cells. In addition, CUDC-101 enhanced gemcitabine-induced apoptosis via inhibited PI3K/Akt/mTOR and Erk pathway activation, as indicated by the phosphorylation status of Akt, 4EBP1, S6 and Erk. We also found that co-treatment with gemcitabine and CUDC-101 not only synergistically suppressed ability of PC cell migration and invasion, but also synergistically inhibited EMT signaling pathway through modulation of cadherin, vimentin and transcription factors Snail, Slug and MMP-9. In vivo, the co-treatment group showed a significant anti-tumor function in the growth of xenograft tumors. Overall, combination of CUDC-101 and gemcitabine significantly increased anti-tumor activities compared with single drug alone, thus supporting a further evaluation of combination treatment for PC. Accordingly, it provides a rationale to investigate the combination of gemcitabine and CUDC-101 as a potential therapeutic strategy for PC.

ILK enhances migration and invasion abilities of human endometrial stromal cells by facilitating the epithelial-mesenchymal transition

Epithelial-mesenchymal transition (EMT) plays a significant part in the pathogenesis of endometriosis by facilitating the migration and invasion abilities of cells. Integrin-linked kinase (ILK) increases the cell migration and invasion abilities by inducing the EMT. Eutopic and control endometrial stromal cells (EuSCs and CSCs) were isolated and cultured. Cell migration and invasion abilities were detected by transwell assays. Levels of proteins were detected by Western blot. EuSCs showed higher levels of ILK, N-cadherin, vimentin and stronger migration and invasion abilities. After transfection of siRNA-ILK, E-cadherin and keratin levels were increased while N-cadherin and vimentin levels were decreased in EuSCs. Besides that, the migration and invasion abilities of EuSCs were significantly decreased after transfection of siRNA-ILK. On the contrary, levels of ILK, N-cadherin and vimentin were increased while levels of E-cadherin and keratin were decreased simultaneously after transfecting CSCs with pEGFP-C1-ILK. Simultaneously, the migration and invasion abilities of CSCs were increased after transfection of pEGFP-C1-ILK. Our study verified that high expression of ILK enhanced the migration and invasion abilities of ESCs by facilitating the EMT. Given that ILK played crucial roles in the pathogenesis of endometriosis, it may be considered as a promising targeted therapy for endometriosis.

Knockdown of long non-coding RNA linc-ITGB1 inhibits cancer stemness and epithelial-mesenchymal transition by reducing the expression of Snail in non-small cell lung cancer

BACKGROUND

The main cause of death in patients with non-small cell lung cancer (NSCLC) is the progression of cancer metastasis, which can be attributed to multiple factors, such as cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT). Long non-coding RNAs (lncRNAs) play important roles in the regulation of the cell cycle, cell proliferation, immune responses, and metastasis in cancers, but the potential roles and mechanisms of lincRNAs in CSC-like properties of cancer have not yet been elucidated.

METHODS

Human NSCLC cell lines (A549 and H1299), highly metastatic cell lines (L9981 and 95D), and their corresponding low-metastatic cell lines (NL9980 and 95C) were subject to quantitative real-time PCR and Western blot, transwell invasion, colony formation, and wound healing assays.

RESULTS

Linc-ITGB1 was greatly upregulated in CSC spheres. Linc-ITGB1 knockdown markedly inhibited CSC formation and the expression of stemness-associated genes, such as Sox2, Nanog, Oct-4, c-Myc, and CD133. Depletion of linc-ITGB1 expression also inhibited the in vitro invasive and migratory potential of cells, and further analysis indicated that linc-ITGB1 knockdown increased the expression of the epithelial marker E-cadherin and downregulated the mesenchymal markers vimentin and fibronectin. The EMT-related transcription factor Snail mediated these effects of linc-ITGB1 in NSCLC, and overexpression of Snail significantly reversed the inhibitory effects of linc-ITGB1 depletion.

CONCLUSION

Overall, our study demonstrated that linc-ITGB1 promoted NSCLC cell EMT and cancer stemness by regulating Snail expression.

Solute Carrier Family 27 Member 4 (SLC27A4) Enhances Cell Growth, Migration, and Invasion in Breast Cancer Cells

Fatty acid metabolism is important in the regulation of breast cancer progression. Some of the proteins involved in fatty acid transport have been demonstrated to promote the proliferation, migration, and invasion in breast cancer cells. Solute carrier family 27 member 4 (SLC27A4) is a fatty acid transporter protein and is related to very long chain acyl-CoA synthetase activity. In the present study, bioinformatic analysis revealed that relatively high SLC27A4 expression was observed in all subtypes of breast tumor tissues when compared to normal breast tissues. Silencing SLC27A4 expression significantly reduced uptake of free fatty acids in two breast cancer cell lines, Hs578T and MDA-MB-231. Cell growth inhibition was observed in SLC27A4-silenced Hs578T and cell cycle was arrested at G2/M. In addition, the capacity of migration and invasion decreased in both cell lines after knockdown of SLC27A4. The epithelial–mesenchymal transition signaling pathway was inhibited because protein expression of Slug, vimentin, α-smooth muscle actin, and other regulators was lower than that in control cells. Taken together, our results confirm that high SLC27A4 is associated with tumor progression in breast cancer cells. It is worth investigating whether SLC27A4 serves a diagnostic marker and therapeutic target in further studies.

Sphingosine kinase 1 promotes the metastasis of colorectal cancer by inducing the epithelial‑mesenchymal transition mediated by the FAK/AKT/MMPs axis

It was demonstrated that Sphingosine kinase 1 (SphK1) promotes tumor progression and confers the malignancy phenotype of colorectal cancer by activating the focal adhesion kinase (FAK) pathway. However, further clarification is required to determine if SphK1 promotes the metastasis of colorectal cancer by inducing epithelial‑mesenchymal transition (EMT), and its mechanisms have not been fully elucidated. Immunohistochemistry staining was used to detect protein expression in normal colonic mucosa tissues and colorectal cancer tissues. Cells were transfected to overexpress SphK1, downregulate SphK1 or downregulate FAK. An MTT assay was used to detect the drug toxicity to cells. Transwell and wound healing assays were used to detect cell migration ability. Reverse transcription‑polymerase chain reaction and western blot analysis were used to detect the expression of mRNA and protein, respectively. Scanning electron microscopy was used to observe the microvilli and pseudopodia of the cells. The analysis of protein expression in 114 human colorectal cancer tissues demonstrated that the expressions of SphK1, FAK, phosphorylated (p)‑FAK, E‑cadherin and vimentin were associated with the metastasis of colorectal cancer. Furthermore, the patients with colorectal cancer with SphK1‑positive cancer demonstrated poorer prognosis compared with SphK1‑negative cancer. FAK knockdown and SphK1 knockdown of human colon cancer RKO cells inhibited the EMT and migrational potency, along with the expression of p‑FAK, p‑protein kinase B (AKT) and matrix metalloproteinase (MMP)2/9. In contrast, SphK1 overexpression promoted EMT, migrational potency, and the expression of p‑FAK, p‑AKT and MMP2/9 in HT29 cells. Additionally, the EMT and migrational potency of SphK1‑overexpressing HT29 cells was suppressed by a FAK inhibitor, and the expression of p‑FAK, p‑AKT and MMP2/9 was suppressed by blocking the FAK pathway. In conclusion, SphK1 promoted the migration and metastasis of colon cancer by inducing EMT mediated by the FAK/AKT/MMPs axis.

MiR-876-5p modulates head and neck squamous cell carcinoma metastasis and invasion by targeting vimentin

BACKGROUND

Local or distant metastasis remains the main course of death in head and neck squamous cell carcinoma (HNSCC) patients. MicroRNAs (miRNAs) have been implicated in metastasis of HNSCC, but the mechanisms of their action are mainly undocumented. Through public head and neck cancer miRNA expression datasets, we found that miR-876-5p was a novel potential tumor suppressor targeting HNSCC metastasis.

METHODS

Clinical significance and mechanism of miR-876-5P was systematically analyzed in HNSCC. Quantitative RT-PCR was used to evaluate miR-876-5p levels in HNSCC cell lines and in 20 pairs of HNSCC with associated regional nodal metastases and HNSCC without metastatic primary tumors. Scratch and invasion assays were evaluated to determine the role of miR-876-5p in the regulation of HNSCC cell migration and invasion, respectively. Western blotting was used to investigate the mechanism by which miR-876-5p suppresses HNSCC cell invasion and migration. Luciferase assays were performed to assess miR-876-5p binding to the vimentin gene. The animal model was used to support the in vitro experimental findings.

RESULTS

MiR-876-5p mimics inhibited HNSCC cell migration and invasion. Vimentin protein and mRNA levels were decreased in the miR-876-5p mimics group but increased in the miR-876-5p inhibitors group, which demonstrated that miR-876-5p inhibits vimentin expression in HNSCC cells. By directly targeting the vimentin 3'-UTR, we used dual-luciferase reporter assays to verify that vimentin is a functional downstream target of miR-876-5p. Importantly, increased vimentin expression promoted cell migration and invasion, and co-transfection with miR-876-5p mimics and vimentin restored cell aggressiveness to the original level. Moreover, miR-876-5p overexpression significantly downregulated vimentin expression level and inhibited the distal metastasis of HNSCC cells in vivo.

CONCLUSIONS

miR-876-5p, which functions as a tumor suppressor in HNSCC, inhibits metastasis by targeting vimentin and provides a novel therapeutic target for HNSCC treatment.

Metastatic tumor cells - genotypes and phenotypes

BACKGROUND

Metastasis is the primary cause of mortality in cancer patients. Therefore, elucidating the genetics and epigenetics of metastatic tumor cells and the mechanisms by which tumor cells acquire metastatic properties constitute significant challenges in cancer research.

OBJECTIVE

To summarize the current understandings of the specific genotype and phenotype of the metastatic tumor cells.

METHOD and RESULT

In-depth genetic analysis of tumor cells, especially with advances in the next-generation sequencing, have revealed insights of the genotypes of metastatic tumor cells. Also, studies have shown that the cancer stem cell (CSC) and epithelial to mesenchymal transition (EMT) phenotypes are associated with the metastatic cascade.

CONCLUSION

In this review, we will discuss recent advances in the field by focusing on the genomic instability and phenotypic dynamics of metastatic tumor cells.

Advances in tumor-endothelial cells co-culture and interaction on microfluidics

The metastasis in which the cancer cells degrade the extracellular matrix (ECM) and invade to the surrounding and far tissues of the body is the leading cause of mortality in cancer patients. With a lot of advancement in the field, yet the biological cause of metastasis are poorly understood. The microfluidic system provides advanced technology to reconstruct a variety of in vivo-like environment for studying the interactions between tumor cells (TCs) and endothelial cells (ECs). This review gives a brief account of both two-dimensional models and three-dimensional microfluidic systems for the analysis of TCs-ECs co-culture as well as their applications to anti-cancer drug screening. Furthermore, the advanced methods for analyzing cell-to-cell interactions at single-cell level were also discussed.

E-Cadherin Loss Accelerates Tumor Progression and Metastasis in a Mouse Model of Lung Adenocarcinoma

Metastatic disease is the primary cause of death of patients with lung cancer, but the mouse models of lung adenocarcinoma do not accurately recapitulate the tumor microenvironment or metastatic disease observed in patients. In this study, we conditionally deleted E-cadherin in an autochthonous lung adenocarcinoma mouse model driven by activated oncogenic Kras and p53 loss. Loss of E-cadherin significantly accelerated lung adenocarcinoma progression and decreased survival of the mice. Kras;p53;E-cadherin mice had a 41% lung tumor burden, invasive grade 4 tumors, and a desmoplastic stroma just 8 weeks after tumor initiation. One hundred percent of the mice developed local metastases to the lymph nodes or chest wall, and 38% developed distant metastases to the liver or kidney. Lung adenocarcinoma cancer cell lines derived from these tumors also had high migratory rates. These studies demonstrate that the Kras;p53;E-cadherin mouse model better emulates the tumor microenvironment and metastases observed in patients with lung adenocarcinoma than previous models and may therefore be useful for studying metastasis and testing new lung cancer treatments in vivo.

Capsaicin inhibits the metastasis of human papillary thyroid carcinoma BCPAP cells through the modulation of the TRPV1 channel

Capsaicin (CAP), a potent transient receptor potential vanilloid type 1 (TRPV1) agonist, is a major ingredient of red pepper. Recently, capsaicin has attracted increasing attention owing to its multiple biological activities. However, the anticancer effects of capsaicin against various types of cancers, especially on thyroid carcinoma, have not been completely elucidated. TRPV1, which can be activated by capsaicin, plays a key role in many biological and physiological processes. In the present study, the anticancer properties of capsaicin against papillary thyroid cancer BCPAP cells were investigated. Our results indicated that TRPV1 and TRPV6 were universally expressed in different types of thyroid cell lines. Capsaicin could inhibit multiple steps of metastasis without affecting the viability of BCPAP cells. The activation of TRPV1 by capsaicin (25-100 μM) significantly suppressed the migration and invasion of BCPAP cells as well as their adhesion. The protein levels of Snail1 and Twist1, two critical EMT transcription factors (EMT-TFs), dramatically decreased in a dose-dependent manner after capsaicin treatment, accompanied by the up-regulation of downstream protein E-cadherin. Subsequently, the activation of TRPV1 by capsaicin also caused significant inhibition of the expression of MMP-2 and MMP-9. Moreover, the inhibitory effects of capsaicin on the metastasis of BCPAP cells were abrogated by the pre-treatment of a specific TRPV1 antagonist (capsazepin). Our results suggest that the activation of TRPV1 by capsaicin is associated with the metastatic inhibition of papillary thyroid cancer BCPAP cells, indicating that targeting of TRPV1 functions remains a feasible strategy for cancer treatment.

Hic-5 expression is a major indicator of cancer cell morphology, migration, and plasticity in three-dimensional matrices

The focal adhesion proteins Hic-5 and paxillin have been previously identified as key regulators of MDA-MB-231 breast cancer cell migration and morphologic mesenchymal-amoeboid plasticity in three-dimensional (3D) extracellular matrices (ECMs). However, their respective roles in other cancer cell types have not been evaluated. Herein, utilizing 3D cell-derived matrices and fibronectin-coated one-dimensional substrates, we show that across a variety of cancer cell lines, the level of Hic-5 expression serves as the major indicator of the cells primary morphology, plasticity, and in vitro invasiveness. Domain mapping studies reveal sites critical to the functions of both Hic-5 and paxillin in regulating phenotype, while ectopic expression of Hic-5 in cell lines with low endogenous levels of the protein is sufficient to induce a Rac1-dependent mesenchymal phenotype and, in turn, increase amoeboid-mesenchymal plasticity and invasion. We show that the activity of vinculin, when coupled to the expression of Hic-5 is required for the mesenchymal morphology in the 3D ECM. Taken together, our results identify Hic-5 as a critical modulator of tumor cell phenotype that could be utilized in predicting tumor cell migratory and invasive behavior in vivo.

USP11 Enhances TGFβ-Induced Epithelial-Mesenchymal Plasticity and Human Breast Cancer Metastasis

Epithelial-mesenchymal transition (EMT) is a conserved cellular plasticity program that is reactivated in carcinoma cells and drives metastasis. Although EMT is well studied its regulatory mechanisms remain unclear. Therefore, to identify novel regulators of EMT, a data mining approach was taken using published microarray data and a group of deubiquitinases (DUB) were found to be upregulated in cells that have undergone EMT. Here, it is demonstrated that one DUB, ubiquitin-specific peptidase 11 (USP11), enhances TGFβ-induced EMT and self-renewal in immortalized human mammary epithelial cells. Furthermore, modulating USP11 expression in human breast cancer cells altered the migratory capacity in vitro and metastasis in vivo Moreover, elevated USP11 expression in human breast cancer patient clinical specimens correlated with decreased survival. Mechanistically, modulating USP11 expression altered the stability of TGFβ receptor type II (TGFBR2) and TGFβ downstream signaling in human breast cancer cells. Together, these data suggest that deubiquitination of TGFBR2 by USP11 effectively spares TGFBR2 from proteasomal degradation to promote EMT and metastasis.Implications: USP11 regulates TGFβ-induced epithelial-mesenchymal plasticity and human breast cancer metastasis and may be a potential therapeutic target for breast cancer. Mol Cancer Res; 16(7); 1172-84. ©2018 AACR.

Evodiamine, a Novel NOTCH3 Methylation Stimulator, Significantly Suppresses Lung Carcinogenesis in Vitro and in Vivo

Lung cancer is a leading cause of cancer-related deaths worldwide. NOTCH3 signaling is mainly expressed in non-small cell lung carcinoma (NSCLC), and has been proposed as a therapeutic target of NSCLC. While, few agents for preventing or treating NSCLC via targeting NOTCH3 signaling are used in modern clinical practice. Evodiamine (EVO), an alkaloid derived from Euodiae Fructus, possesses low toxicity and has long been shown to exert anti-lung cancer activity. However, the underlying anti-lung cancer mechanisms of EVO are not yet fully understood. In this study, we explored the involvement of NOTCH3 signaling in the anti-lung cancer effects of EVO. Urethane-induced lung cancer mouse model and two NSCLC cell models, A549 and H1299, were used to evaluate the in vivo and in vitro anti-lung cancer action of EVO. A DNA methyltransferase inhibitor was employed to investigate the role of NOTCH3 signaling in the anti-lung cancer effects of EVO. Results showed that EVO potently reduced tumor size and tumor numbers in mice, and inhibited NOTCH3 in the tumors. EVO also dramatically reduced cell viability, induced G2/M cell cycle arrest, inhibited cell migration and reduced stemness in cultured NSCLC cells. Mechanistic studies showed that EVO potently inhibited NOTCH3 signaling by activation of DNMTs-induced NOTCH3 methylation. Importantly, inhibition of NOTCH3 methylation in NSCLC cells diminished EVO's anti-NSCLC effects. Collectively, EVO, a novel NOTCH3 methylation stimulator, exerted potent anti-lung cancer effects partially by inhibiting NOTCH3 signaling. These findings provide new insight into the EVO's anti-NSCLC action, and suggest a potential role of EVO in lung cancer prevention and treatment.

Periostin, a signal transduction intermediate in TGF-β-induced EMT in U-87MG human glioblastoma cells, and its inhibition by anthocyanidins

Periostin is a secreted protein that is highly expressed in glioblastoma cells as compared to normal brain tissue, and is therefore considered as a potential biomarker in therapeutic modalities. Its contribution in the cancer cells invasive phenotype is, however, poorly understood. This work investigates the role of periostin in U-87 MG glioblastoma cell invasion, cell migration and in Transforming Growth Factor β (TGF-β)-induced epithelial-mesenchymal transition (EMT). Periostin gene silencing, using small interfering RNA, decreased TGF-β-induced mesenchymal marker expression of fibronectin and vimentin, partly through reduced Smad2, Akt and Fak phosphorylation as well as U-87 MG cell invasion and migration. The effects of anthocyanidins, the most abundant diet-derived flavonoids, were examined on periostin-mediated downstream signaling pathways. Anthocyanidins were found to decrease periostin expression whether added under pre-, co- or post-treatment conditions along with TGF-β, and altered the Akt and Fak signaling pathways. These effects were similar to Galunisertib (LY2157299), a small molecule inhibitor of the TGF-β receptor I kinase. Taken together, our data demonstrate that periostin acts as a central element in TGF-β-induced EMT, which can be prevented by diet-derived anthocyanidins.

Human Cancer and Platelet Interaction, a Potential Therapeutic Target

Cancer patients experience a four-fold increase in thrombosis risk, indicating that cancer development and progression are associated with platelet activation. Xenograft experiments and transgenic mouse models further demonstrate that platelet activation and platelet-cancer cell interaction are crucial for cancer metastasis. Direct or indirect interaction of platelets induces cancer cell plasticity and enhances survival and extravasation of circulating cancer cells during dissemination. In vivo and in vitro experiments also demonstrate that cancer cells induce platelet aggregation, suggesting that platelet-cancer interaction is bidirectional. Therefore, understanding how platelets crosstalk with cancer cells may identify potential strategies to inhibit cancer metastasis and to reduce cancer-related thrombosis. Here, we discuss the potential function of platelets in regulating cancer progression and summarize the factors and signaling pathways that mediate the cancer cell-platelet interaction.

AIMP2-DX2 Promotes the Proliferation, Migration, and Invasion of Nasopharyngeal Carcinoma Cells

Nasopharyngeal carcinoma (NPC) is a head and neck tumor with high degree of malignancy and with high incidence especially in southern China. AIMP2-DX2, one isoform of the aminoacyl-tRNA synthetase interacting multifunctional proteins (AIMPs), is shown to be a potential target in many cancers. However, the detailed mechanisms of AIMP2-DX2 in NPC development remain to be elucidated. Here, we found that the mRNA expression level of AIMP2-DX2 was significantly increased in NPC specimens, compared with normal nasopharyngeal tissues. Microarray immunohistochemical analysis of NPC specimens and Kaplan–Meier analysis showed that patients with high AIMP2-DX2 protein expression had shorter overall survival than those with low AIMP2-DX2 level. Furthermore, mRNA and protein expression levels of AIMP2-DX2 were both increased in cultured NPC cell lines (5-8F, CNE-2Z, and CNE-1), by being compared with normal nasopharyngeal cell line NP69. Overexpression of AIMP2-DX2 remarkably promoted the cell viability, cell migration, and invasion of cultured NPC cells. Genetic knockdown of AIMP2-DX2 by shRNA lentiviruses significantly suppressed the proliferation, migration, and invasion and induced apoptosis of NPC cells. Inhibition of AIMP2-DX2 decreased the highly expressed level of matrix metalloproteinase- (MMP-) 2 and MMP-9, further suppressed proliferation, migration, and invasion in cultured NPC cells in vitro, and inhibited tumor growth in a xenograft mouse model in vivo. Taken together, these results suggest that AIMP2-DX2 plays an important role in the regulation of NPC and could be a potential therapeutic target and prognostic indicator for the treatment of NPC.

Benzidine Induces Epithelial-Mesenchymal Transition of Human Bladder Cancer Cells through Activation of ERK5 Pathway

Benzidine, a known carcinogen, is closely associated with the development of bladder cancer (BC). Epithelial-mesenchymal transition (EMT) is a critical pathophysiological process in BC progression. The underlying molecular mechanisms of mitogen-activated protein kinase (MAPK) pathway, especially extracellular regulated protein kinases 5 (ERK5), in regulating benzidine-induced EMT remains unclarified. Hence, two human bladder cell lines, T24 and EJ, were utilized in our study. Briefly, cell migration was assessed by wound healing assay, and cell invasion was determined by Transwell assay. Quantitative PCR and western blot were utilized to determine both gene expressions as well as protein levels of EMT and MAPK, respectively. Small interfering RNA (siRNA) was transfected to further determine ERK5 function. As a result, the migration and invasion abilities were enhanced, epithelial marker expression was decreased while mesenchymal marker expression was increased in human BC cell lines. Meanwhile, benzidine administration led to activation of ERK5 and activator protein 1 (AP-1) proteins, without effective stimulation of the Jun N-terminal kinase (JNK) or p38 pathways. Moreover, Benzidine-induced EMT and ERK5 activation were completely suppressed by XMD8-92 and siRNAs specific to ERK5. Of note, ERK1/2 was activated in benzidine-treated T24 cells, while benzidine-induced EMT could not be reversed by U0126, an ERK1/2 inhibitor, as indicated by further study. Collectively, our findings revealed that ERK5-mediated EMT was critically involved in benzidine-correlated BC progression, indicating the therapeutic significance of ERK5 in benzidine-related BC.

SNAIL1 action in tumor cells influences macrophage polarization and metastasis in breast cancer through altered GM-CSF secretion

The EMT inducer SNAIL1 regulates breast cancer metastasis and its expression in human primary breast tumor predicts for poor outcomes. During tumor progression SNAIL1 has multiple effects in tumor cells that can impact metastasis. An inflammatory tumor microenvironment also impacts metastasis and recently SNAIL1 has been implicated as modulating the secretion of cytokines that can influence the tumor immune infiltrate. Using a spontaneous genetic model of breast cancer metastasis and syngeneic orthotopic transplant experiments we show that the action of SNAIL1 in primary breast tumor cells is required for breast tumor growth and metastasis. It does so, in part, by regulating production of GM-CSF, IL1α, IL-6, and TNFα by breast cancer cells. The SNAIL1-dependent tumor cell secretome modulates the primary tumor-associated macrophage (TAM) polarization. GM-CSF alone modulates TAM polarization and impacts breast cancer metastasis in vivo. This study highlights another role for breast tumor SNAIL1 in cancer progression to metastasis-modulation of the immune microenvironment of primary breast tumors.

Pro-apoptotic Bax promotes mesenchymal-epithelial transition by binding to respiratory complex-I and antagonizing the malignant actions of pro-survival Bcl-2 proteins

The plasticity of solid tumors between the epithelial and mesenchymal states critically influences their malignant progression and metastasis. The epithelial-mesenchymal transition (EMT), which supports cancer cell invasion and metastasis, is promoted by pro-survival members (e.g., Bcl-2 and Bcl-X_L) of the Bcl-2 protein family, which are well-known key apoptosis regulators. We found that Bcl-w, another pro-survival member, promotes EMT by increasing respiratory complex-I activity and reactive oxygen species (ROS) levels. In contrast, pro-apoptotic Bax facilitates mesenchymal-epithelial transition by binding to complex-I, which inhibits complex-I-induced ROS production. Functional antagonism between pro-survival and pro-apoptotic proteins in regulating tumor plasticity was directly confirmed by co-expressing Bax with Bcl-w or Bcl-X_L. Therefore, the balance between the functionally opposing Bcl-2 proteins appears to be a critical determinant of cancer cell phenotypes. We further showed that sub-lethal doses of γ-radiation induced EMT by increasing Bcl-X_L and Bcl-w levels and complex-I activity. We propose that Bcl-2 proteins and complex-I are potential targets for preventing tumor progression and the malignant actions of radiotherapy.

miR-519d-3p Inhibits Cell Proliferation and Invasion of Gastric Cancer by Downregulating B-Cell Lymphoma 6

miR-519d inhibits cell growth, migration, and invasion, but its role in gastric cancer (GC) cells is obscure. We showed that miR-519d-3p was lowly expressed in GC tissues and was associated with the clinical stage and lymph node metastasis of GC tissues. We found that miR-519d-3p repressed cell proliferation and invasion of MGC803 cells and delayed the G1/S phase transition, resulting in decreased cyclin B1 and MMP2 and increased E-cadherin levels. Furthermore, miR-519d-3p targeted and downregulated B-cell lymphoma 6 (BCL6) expression. BCL6 overexpression partially abrogated the suppressive function of miR-519d in MGC803 cells. In conclusion, our study demonstrated that miR-519d-3p functions as a tumor suppressor by targeting and downregulating the expression of BCL6 in GC cells.

Trends of uterine carcinosarcoma in the United States

OBJECTIVE

Uterine carcinosarcoma (UCS) is a rare type of high-grade endometrial cancer (EC) that has been understudied with population-based statistics due to its rarity. This study examined temporal trends in the proportion of UCS among women with EC.

METHODS

This is a retrospective observational study examining The Surveillance, Epidemiology, and End Results program between 1973-2013. Primary EC cases were eligible for analysis, and a time-specific proportion of UCS was examined during the study period.

RESULTS

UCS was seen in 11,000 (4.7%) women among 235,849 primary EC cases. Mean age at UCS diagnosis increased from 65.9 to 71.7 years between 1973-1989 and then decreased from 71.7 to 67.0 years between 1989-2013 (both, p<0.001). Proportion of Black women significantly increased during the study period (11.9%-20.0%, p<0.001), whereas the proportion of White women decreased from 86.0% to 60.5% between 1987-2013 (p<0.001). There was a significant increase in the proportion of UCS among primary EC from 1.7% to 5.6% between 1973-2013 (p<0.001). Among type II ECs (n=76,118), the proportion of UCS also increased significantly from 6.0% to 17.5% between 1973-2013 (p<0.001). An increasing proportion of UCS was seen in both young and older women but the magnitude of interval increase was larger in the older age group between 1973-2013 (<60 years, from 1.3% to 3.3%. p<0.001; and ≥60 years, from 2.6% to 7.0%, p<0.001).

CONCLUSION

Our study demonstrated that the proportion of UCS has significantly increased among EC, accounting for more than 5% in recent years.

YAP promotes breast cancer metastasis by repressing growth differentiation factor-15

The transcriptional co-activator Yes-associated protein (YAP) has been implicated as an oncogene and is found to promote breast cancer metastasis. However, the pro-metastatic mechanism of YAP remains unclear. Here, we demonstrated that YAP functions as a transcriptional repressor of growth differentiation factor-15 (GDF15), a divergent member of the transforming growth factor superfamily, in several breast cancer cell lines. Functionally, knockdown of YAP decreased, whereas knockdown of GDF15 increased, the metastatic potential of breast cancer cells. More than that, the reduced metastasis in YAP-depleted cells could be reversed by simultaneous knockdown of GDF15. Mechanistically, the repressive effect of YAP on GDF15 requires its transcriptional factor TEAD (TEA domain family). In addition, YAP recruits polycomb repressive complex 2 (PRC2) to tri-methylate histone H3 lysine 27 in the promoter region of GDF15. Co-immunoprecipitation experiments demonstrated that YAP and enhancer of zeste 2 PRC2 subunit (EZH2) physically interact with each other. In conclusion, our data reveal that YAP promotes metastasis of breast cancer cells by repressing GDF15 transcription and present a novel molecular mechanism underlying the pro-metastasis function of YAP oncoprotein, with the implication of a therapeutic avenue for breast cancer treatment.

Antitumor effects of metformin are a result of inhibiting nuclear factor kappa B nuclear translocation in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is an intractable digestive organ cancer that has proven difficult to treat despite multidisciplinary therapy, and a new treatment strategy is demanded. Metformin is used for type 2 diabetes mellitus and its antitumor effects have been reported recently. Metformin exerts antitumor effects in various respects, such as inhibiting inflammation, tumor growth and epithelial‐mesenchymal transition (EMT). However, few reports have described the efficacy of metformin on ESCC, and their findings have been controversial. We analyzed the antitumor effects of metformin and clarified its effects on anti‐inflammation, growth suppression and EMT inhibition. Activation of nuclear factor kappa B (NF‐κB), the major transcription factor induced by inflammation, was investigated by immunostaining. We found that localization of NF‐κB in the nucleus was reduced after metformin treatment. This suggests that metformin inhibited the activation of NF‐κB. Metformin inhibited tumor growth and induced apoptosis in ESCC cell lines. Associated with EMT, we examined cell motility by a wound healing assay and the epithelial marker E‐cadherin expression of various ESCC cell lines by western blotting. Metformin inhibited cell motility and induced E‐cadherin expression. In conclusion, metformin showed multiple antitumor effects such as growth suppression, invasion inhibition, and control of EMT by inhibiting NF‐κB localization on ESCC. Further exploration of the marker of treatment efficacy and combination therapy could result in the possibility for novel treatment to use metformin on ESCC.

A novel microRNA identified in hepatocellular carcinomas is responsive to LEF1 and facilitates proliferation and epithelial-mesenchymal transition via targeting of NFIX

Hepatocellular carcinoma (HCC) is one of the most prevalent cancers. It has been demonstrated that various cellular microRNAs (miRNAs) play an important role in HCC development. Here, we analyzed the miRNA profile in HCC tissues by Solexa sequencing, and we identified a novel microRNA, miR-HCC1, which is upregulated in HCC tissues. Further experiments showed that miR-HCC1 promoted HCC cell proliferation in vivo and in vitro, and migration and invasion resulting from the epithelial-mesenchymal transition (EMT) process. Nuclear factor I/X (NFIX), which inhibited cell proliferation, migration and invasion in HCC cells, was identified as a direct and functional target of miR-HCC1. Furthermore, lymphoid enhancer binding factor 1 (LEF1), a transcription factor, was shown to bind the promoter of miR-HCC1 and activate its expression. Collectively, these results indicate that LEF1-upregulated miR-HCC1 functions as an oncogene through the negative regulation of NFIX expression, which links the LEF1/miR-HCC1/NFIX axis to contribute to cell proliferation, migration and invasion of HCC cells and could provide novel insights into miRNA function and hepatocarcinogenesis and potential biomarkers for HCC.