Nodal promotes aggressive phenotype via Snail-mediated epithelial–mesenchymal transition in murine melanoma

Interleukin-1 beta signals through the ERK signalling pathway to modulate human placental trophoblast migration and invasion in the first trimester of pregnancy

INTRODUCTION

Interleukin-1 beta (IL-1β) can promote cell migration, invasion and metastasis in various cancer cells. The mechanism of its role in human trophoblast has not been fully investigated. Therefore, we aimed to investigate the expression level of IL-1β in first trimester decidua and placenta and its potential role in regulation of extravillous trophoblast cell (EVT) invasion and migration.

METHODS

First trimester placenta and decidua were collected to study the expression levels of IL-1β and its receptors by immunohistochemical staining. Primary isolates of first trimester EVT or the HTR-8/SVneo trophoblast like cell line were used to assess migration and invasion. Matrix metalloproteinase levels were assessed by gelatin zymography and ELISA. The phosphorylation profile of signaling pathway proteins was detected with the Proteome Profiler Human Phospho-Kinase Array Kit. Differentially expressed proteins in cells was detected and verified by Western Blot.

RESULTS

IL-1β, its receptors and antagonist are expressed in first trimester placenta and decidua, exogenous IL-1β stimulates trophoblast cell outgrowth, migration and invasion through the ERK signaling pathway. IL-1β was significantly increased in the placenta at 6-7 weeks gestation compared with 8-9 weeks gestation (P < 0.0001). Transwell and RTCA assays indicated that IL-1β stimulates the invasion and migration of EVT. In addition, IL-1β promoted the phosphorylation of ERK 1/2. It also promoted the expression of MMP2 and MMP9 in EVT as demonstrated by gelatin zymography assay and enzyme linked immunosorbent assay.

DISCUSSION

This study demonstrated IL-1β expression in placenta and decidua, and that it regulates EVT invasion and migration.

Cyclic Stretching Enhances Angiocrine Signals at Liver Bud Stage from Human Pluripotent Stem Cells in Two-Dimensional Culture

Angiocrine signals during the development and growth of organs, including the liver, intestine, lung, and bone, are essential components of intercellular communication. The signals elicited during the liver bud stage are critical for vascularization and enhanced during the intercellular communication between the cells negative for kinase insert domain receptor (KDR) (KDR- cells) and the cells positive for KDR (KDR+ cells), which constitute the liver bud. However, the use of a human pluripotent stem cell (hPSC)-derived system has not facilitated the generation of a perfusable vascularized liver organoid that allows elucidation of liver development and has great potential for liver transplantation. This is largely owing to the lack of fundamental understanding to induce angiocrine signals in KDR- and KDR+ cells during the liver bud stage. We hypothesized that mechanical stimuli of cyclic stretching/pushing by the fetal heart adjacent to the liver bud could be the main contributor to promoting angiocrine signals in KDR- and KDR+ cells during the liver bud stage. In this study, we show that an organ-on-a-chip platform allows the emulation of an in vivo-like mechanical environment for the liver bud stage in vitro and investigate the role of cyclic mechanical stretching (cMS) to angiocrine signals in KDR- and KDR+ cells derived from hPSCs. RNA sequencing revealed that the expression of genes associated with epithelial-to-mesenchymal transition, including angiocrine signals, such as hepatocyte growth factor (HGF) and matrix metallopeptidase 9 (MMP9), were increased by cMS in cocultured KDR- and KDR+ cells. The expression and secretions of HGF and MMP9 were increased by 1.98- and 1.69-fold and 3.23- and 3.72-fold with cMS in the cocultured KDR- and KDR+ cells but were not increased by cMS in the monocultured KDR- and KDR+ cells, respectively. Finally, cMS during the liver bud stage did not lead to the dedifferentiation of hepatocytes, as the cells with cMS showed hepatic maker expression (CYP3A4, CYP3A7, ALB, and AAT) and 1.71-fold higher CYP3A activity than the cells without cMS, during 12 day-hepatocyte maturation after halting cMS. Our findings provide new insights into the mechanical factors during the liver bud stage and directions for future improvements in the engineered liver tissue.

CCL5/CCR5 axis in human diseases and related treatments

To defense harmful stimuli or maintain the immune homeostasis, the body produces and recruits a superfamily of cytokines such as interleukins, interferons, chemokines etc. Among them, chemokines act as crucial regulators in defense systems. CCL5/CCR5 combination is known for facilitating inflammatory responses, as well as inducing the adhesion and migration of different T cell subsets in immune responses. In addition, recent studies have shown that the interaction between CCL5 and CCR5 is involved in various pathological processes including inflammation, chronic diseases, cancers as well as the infection of COVID-19. This review focuses on how CCL5/CCR5 axis participates in the pathological processes of different diseases and their relevant signaling pathways for the regulation of the axis. Moreover, we highlighted the gene therapy and chemotherapy studies for treating CCR5-related diseases, including the ongoing clinical trials. The barriers and perspectives for future application and translational research were also summarized.

Low-Dose Albendazole Inhibits Epithelial-Mesenchymal Transition of Melanoma Cells by Enhancing Phosphorylated GSK-3β/Tyr216 Accumulation

Albendazole (ABZ) is an effective broad-spectrum anthelmintic agent that has been widely used for humans and animals. Previous studies have reported that ABZ exhibits antitumor effects against melanoma and other different cancer types; however, it is unknown whether ABZ exerts the inhibitory effect against melanoma metastasis. In this study, we aimed to investigate the inhibitory effect of ABZ on melanoma cells. Through in vitro studies, we discovered that low-dose ABZ treatment significantly inhibited the migration and invasion, but not the proliferation, of A375 and B16-F10 cells in a dose-dependent manner. Further analysis revealed that ABZ treatment reduced the expression level of snail family transcriptional repressor 1 (Snail) in the cytoplasm and nucleus by decreasing the levels of phosphorylated AKT (pAKT) Ser473/GSK-3β (pGSK-3β) Ser9 and increasing pGSK-3β/Tyr216, resulting in a significant upregulation of E-cadherin and downregulation of N-cadherin and ultimately reversing the epithelial-mesenchymal transition (EMT) process of melanoma cells. In contrast, the continuous activation of AKT via transfected plasmids elevated the protein levels of pAKT Ser473/pGSK-3β Ser9 and Snail and antagonized the inhibitory action of ABZ. We also confirmed that ABZ treatment effectively inhibited the lung metastasis of melanoma in nude mice in vivo. Subsequent immunohistochemical analysis verified the decreased pAKT Ser473/pGSK-3β Ser9 and increased pGSK-3β/Tyr216 levels in ABZ-treated subcutaneous tumors. Therefore, our findings demonstrate that ABZ treatment can suppress the EMT progress of melanoma by increasing the pGSK-3β/Tyr216-mediated degradation of Snail, which may be used as a potential treatment strategy for metastatic melanoma.

Bone morphogenetic protein induces bone invasion of melanoma by epithelial-mesenchymal transition via the Smad1/5 signaling pathway

Oral malignant melanoma, which frequently invades the hard palate or maxillary bone, is extremely rare and has a poor prognosis. Bone morphogenetic protein (BMP) is abundantly expressed in bone matrix and is highly expressed in malignant melanoma, inducing an aggressive phenotype. We examined the role of BMP signaling in the acquisition of an aggressive phenotype in melanoma cells in vitro and in vivo. In five cases, immunohistochemistry indicated the phosphorylation of Smad1/5 (p-Smad1/5) in the nuclei of melanoma cells. In the B16 mouse and A2058 human melanoma cell lines, BMP2, BMP4, or BMP7 induces morphological changes accompanied by the downregulation of E-cadherin, and the upregulation of N-cadherin and Snail, markers of epithelial-mesenchymal transition (EMT). BMP2 also stimulates cell invasion by increasing matrix metalloproteinase activity in B16 cells. These effects were canceled by the addition of LDN193189, a specific inhibitor of Smad1/5 signaling. In vivo, the injection of B16 cells expressing constitutively activated ALK3 enhanced zygoma destruction in comparison to empty B16 cells by increasing osteoclast numbers. These results suggest that the activation of BMP signaling induces EMT, thus driving the acquisition of an aggressive phenotype in malignant melanoma.

Melanoma Plasticity: Promoter of Metastasis and Resistance to Therapy

Melanoma is the deadliest form of skin cancer. Although targeted therapies and immunotherapies have revolutionized the treatment of metastatic melanoma, most patients are not cured. Therapy resistance remains a significant clinical challenge. Melanoma comprises phenotypically distinct subpopulations of cells, exhibiting distinct gene signatures leading to tumor heterogeneity and favoring therapeutic resistance. Cellular plasticity in melanoma is referred to as phenotype switching. Regardless of their genomic classification, melanomas switch from a proliferative and differentiated phenotype to an invasive, dedifferentiated and often therapy-resistant state. In this review we discuss potential mechanisms underpinning melanoma phenotype switching, how this cellular plasticity contributes to resistance to both targeted therapies and immunotherapies. Finally, we highlight novel strategies to target plasticity and their potential clinical impact in melanoma.

Blockade of TGF-βR improves the efficacy of doxorubicin by modulating the tumor cell motility and affecting the immune cells in a melanoma model

TGF-β contributes to drug resistance and the invasiveness of tumor cells and weakens the anti-tumor immune responses. The present study aimed at examining the efficacy of the combination of SB431542, as a specific inhibitor of TGF-βR, and doxorubicin in controlling the melanoma tumor in mice. The impact of the combination of the doxorubicin and SB431542 on the cell growth, apoptosis, migration, and invasiveness of B16-F10 cells was examined. Besides, the B16-F10 tumor was induced in C57BL/6 mice, and the effects of the mentioned treatment on the tumor volume, survival, and the exhaustion state of T cells were evaluated. Although the combination of doxorubicin and SB431542 did not exhibit synergism in the inhibition of cell growth and apoptosis induction, it efficiently prohibited the migration and the epithelial to mesenchymal transition of B16-F10 cells, and the combination of doxorubicin and SB431542 caused an increase in mRNA levels of E-cadherin and, on the other hand, led to a decline in the expression of Vimentin. Tumor volume and the survival of tumor-bearing mice were efficiently controlled by the combination therapy. This treatment also eventuated in a decrease in the percentage of PD-L1⁺, TCD4⁺, and TCD8⁺ cells as indicators of exhausted T cells within the spleens of tumor-bearing mice. Blockade of TGF-βR also propelled the RAW 264.7 cells towards an anti-tumor M1 macrophage phenotype. The inhibition of TGF-βR demonstrated a potential to increase the efficacy of doxorubicin chemotherapy by the means of affecting cellular motility and restoring the anti-tumor immune responses.

Role of SALL4 and Nodal in the prognosis and tamoxifen resistance of estrogen receptor-positive breast cancer

Despite the discovery of a number of different mechanisms underlying tamoxifen resistance, its molecular pathway is not completely clear. The upregulation of SALL4 and Nodal has been reported in breast cancer. Nevertheless, their role in tamoxifen resistance has not been investigated. In the present study, we compared Nodal and SALL4 expression in 72 tamoxifen sensitive (TAMS) and tamoxifen-resistant (TAMR) patients. Afterward, the correlation of expression data with clinicopathological features and survival of patients was studied. Results showed that both SALL4 and Nodal were significantly upregulated in TAMR compared to TAMS patients. Besides, there was a positive association between Nodal and SALL4 expression. Furthermore, we evaluated their correlation with the expression of Oct4, Nanog and Sox2 stemness markers. The results demonstrated that in most tissue samples there was a positive correlation between Nodal and SALL4 expression with these stemness markers. Besides, the overexpression of SALL4 and Nodal significantly correlated with the N stage. Moreover, the overexpression of SALL4 was associated with extracapsular invasion and lymphatic invasion. High level expressions of SALL4 and Nodal had a significant association with worse disease-free survival (DFS) rates. In addition, increased level of Nodal expression provides a superior predictor factor for DFS. The multivariate Cox regression analysis also revealed that for DFS, perineural invasion (PNI) was independently an unfavorable prognostic value. These findings suggest that the high expression of SALL4 and Nodal could contribute to tamoxifen resistance and worse survival rates in tamoxifen-treated ER⁺ breast cancer patients.

Salmonella Impacts Tumor-Induced Macrophage Polarization, and Inhibits SNAI1-Mediated Metastasis in Melanoma

Targeting metastasis is a vital strategy to improve the clinical outcome of cancer patients, specifically in cases with high-grade malignancies. Here, we employed a Salmonella-based treatment to address metastasis. The potential of Salmonella as an anticancer agent has been extensively studied; however, the mechanism through which it affects metastasis remains unclear. This study found that the epithelial-to-mesenchymal transition (EMT) inducer SNAI1 was markedly reduced in Salmonella-treated melanoma cells, as revealed by immunoblotting. Furthermore, wound healing and transwell assays showed a reduced in vitro cell migration following Salmonella treatment. Transfection experiments confirmed that Salmonella acted against metastasis by suppressing protein kinase B (Akt)/mammalian target of rapamycin (mTOR) signaling, which in turn inhibited SNAI1 expression. Since it is known that metastasis is also influenced by inflammation, we partly characterized the immune infiltrates in melanoma as affected by Salmonella treatment. We found through tumor-macrophage co-culture that Salmonella treatment increased high mobility group box 1 (HMGB1) secretion in tumors to coax the polarization of macrophages in favor of an M1-like phenotype, as shown by increased inducible nitric oxide synthase (iNOS) expression and Interleukin 1 Beta (IL-1β) secretion. Data from our animal study corroborated the in vitro findings, wherein the Salmonella-treated group obtained the lowest lung metastases, longer survival, and increased iNOS-expressing immune infiltrates.

Total saponins from Rubus parvifolius L. inhibits cell proliferation, migration and invasion of malignant melanoma in vitro and in vivo

Background: Total saponins from Rubus parvifolius L. (TSRP) are the main bioactive fractions responsible for the anti-tumor activities. The work was aimed to evaluate the anti-tumor effect of TSRP in malignant melanoma (MM) in vitro and in vivo.

Methods and results: Anti-melanoma cell proliferation, invasion and migration effect of TSRP were detected in human MM A375 cells under the indicated time and dosages. In vivo anti-tumor effect of TSRP was measured in A375 xenograft immunodeficient nude mice. Sixty A375 xenografts were randomly divided into five groups: Vehicle, cyclophosphamide (CTX, 20 mg/kg), TSRP (25 mg/kg), TSRP (50 mg/kg) and TSRP (100 mg/kg) groups for 14 days’ treatment. In addition, the melanoma metastasis in lung in vivo of TSRP was detected in A375 tail vein injection mice, and the histopathalogical analysis of the lung metastasis was detected by Hematoxylin–Eosin (H&E) staining. TSRP significantly inhibited the cell proliferation, invasion and migration of A375 in vitro at the indicated time and dosages. TSRP treatment effectively blocked the tumor growth in immunodeficient nude mice. In addition, TSRP also significantly inhibited the lung metastasis of melanoma.

Conclusion: The present study indicated that the TSRP has a remarkable anti-MM effect, which mainly through the inhibition of the cell invasion, migration and tumor metastasis.

Reemergence of neural crest stem cell-like states in melanoma during disease progression and treatment

Melanoma is the deadliest of all skin cancers due to its high metastatic potential. In recent years, advances in targeted therapy and immunotherapy have contributed to a remarkable progress in the treatment of metastatic disease. However, intrinsic or acquired resistance to such therapies remains a major obstacle in melanoma treatment. Melanoma disease progression, beginning from tumor initiation and growth to acquisition of invasive phenotypes and metastatic spread and acquisition of treatment resistance, has been associated with cellular dedifferentiation and the hijacking of gene regulatory networks reminiscent of the neural crest (NC)—the developmental structure which gives rise to melanocytes and hence melanoma. This review summarizes the experimental evidence for the involvement of NC stem cell (NCSC)‐like cell states during melanoma progression and addresses novel approaches to combat the emergence of stemness characteristics that have shown to be linked with aggressive disease outcome and drug resistance.

The B7-H4 gene induces immune escape partly via upregulating the PD-1/Stat3 pathway in non-small cell lung cancer

Non-small cell lung cancer (NSCLC) is associated with high mortality rates worldwide. The costimulatory molecule, B7-H4, a member of the B7 family, plays an important role in immune regulation, mainly by inhibiting the proliferation of T cells to achieve a negative regulatory T cell immune response. The mechanism of action of B7-H4 in non-small cell lung cancer is unknown at present. Tumor tissues from 71 patients subjected to radical pneumonectomy were examined, along with NSCLC cells and BALB/c mice. Among the 71 NSCLC cases, overall and recurrence-free survival rates were significantly lower in those displaying high B7-H4 expression. Mechanistic analyses showed that B7-H4 promoted the growth and metastasis of non-small cell lung cancer tumor tissues in mice through effects on CD8⁺ T cell apoptosis. Data from western blot experiments further suggested that B7-H4 induced CD8⁺ T cell death, both in vitro and in vivo, and affecting the PD-1/Stat3 pathway and promoting immune escape of tumor cells. Our collective findings support the potential utility of B7-H4 gene expression as a marker of NSCLC prognosis and provide a novel strategy for targeted therapy.

Downregulation of Nodal inhibits metastatic progression in retinoblastoma

Retinoblastoma is the most common intraocular malignancy in children. We previously found that the ACVR1C/SMAD2 pathway is significantly upregulated in invasive retinoblastoma samples from patients. Here we studied the role of an ACVR1C ligand, Nodal, in regulating growth and metastatic dissemination in retinoblastoma. Inhibition of Nodal using multiple short hairpin (shRNAs) in WERI Rb1 and Y79 retinoblastoma cell cultures reduced growth by more than 90%, as determined by CCK-8 growth assay. Proliferation was also significantly inhibited, as found by Ki67 assay. These effects were paralleled by inhibition in the phosphorylation of the downstream effector SMAD2, as well as induction of apoptosis, as we observed more than three-fold increase in the percentage of cells positive for cleaved-caspase-3 or expressing cleaved-PARP1. Importantly, we found that downregulation of Nodal potently suppressed invasion in vitro, by 50 to 80%, as determined by transwell invasion assay (p = 0.02). Using an orthotopic model of retinoblastoma in zebrafish, we found 34% reduction in the ability of the cells to disseminate outside the eye, when Nodal was knocked down by shRNA (p = 0.0003). These data suggest that Nodal plays an important role in promoting growth, proliferation and invasion in retinoblastoma, and can be considered a new therapeutic target for both primary tumor growth and metastatic progression.

Targeting Nodal and Cripto-1: Perspectives Inside Dual Potential Theranostic Cancer Biomarkers

BACKGROUND

Elucidating the mechanisms of recurrence of embryonic signaling pathways in tumorigenesis has led to the discovery of onco-fetal players which have physiological roles during normal development but result aberrantly re-activated in tumors. In this context, Nodal and Cripto-1 are recognized as onco-developmental factors, which are absent in normal tissues but are overexpressed in several solid tumors where they can serve as theranostic agents.

OBJECTIVE

To collect, review and discuss the most relevant papers related to the involvement of Nodal and Cripto-1 in the development, progression, recurrence and metastasis of several tumors where they are over-expressed, with a particular attention to their occurrence on the surface of the corresponding sub-populations of cancer stem cells (CSC).

RESULTS

We have gathered, rationalized and discussed the most interesting findings extracted from some 370 papers related to the involvement of Cripto-1 and Nodal in all tumor types where they have been detected. Data demonstrate the clear connection between Nodal and Cripto-1 presence and their multiple oncogenic activities across different tumors. We have also reviewed and highlighted the potential of targeting Nodal, Cripto-1 and the complexes that they form on the surface of tumor cells, especially of CSC, as an innovative approach to detect and suppress tumors with molecules that block one or more mechanisms that they regulate.

CONCLUSION

Overall, Nodal and Cripto-1 represent two innovative and effective biomarkers for developing potential theranostic anti-tumor agents that target normal as well as CSC subpopulations and overcome both pharmacological resistance and tumor relapse.

Uveal Melanoma, Angiogenesis and Immunotherapy, Is There Any Hope?

Uveal melanoma is considered a rare disease but it is the most common intraocular malignancy in adults. Local treatments are effective, but the systemic recurrence rate is unacceptably high. Moreover, once metastasis have developed the prognosis is poor, with a 5-year survival rate of less than 5%, and systemic therapies, including immunotherapy, have rendered poor results. The tumour biology is complex, but angiogenesis is a highly important pathway in these tumours. Vasculogenic mimicry, the ability of melanomas to generate vascular channels independently of endothelial cells, could play an important role, but no effective therapy targeting this process has been developed so far. Angiogenesis modulates the tumour microenvironment of melanomas, and a close interplay is established between them. Therefore, combining immune strategies with drugs targeting angiogenesis offers a new therapeutic paradigm. In preclinical studies, these approaches effectively target these tumours, and a phase I clinical study has shown encouraging results in cutaneous melanomas. In this review, we will discuss the importance of angiogenesis in uveal melanoma, with a special focus on vasculogenic mimicry, and describe the interplay between angiogenesis and the tumour microenvironment. In addition, we will suggest future therapeutic approaches based on these observations and mention ways in which to potentially enhance current treatments.

Nodal pathway activation due to Akt1 suppression is a molecular switch for prostate cancer cell epithelial-to-mesenchymal transition and metastasis

Several studies have unraveled the negative role of Akt1 in advanced cancers, including metastatic prostate cancer (mPCa). Hence, understanding the consequences of targeting Akt1 in the mPCa and identifying its downstream novel targets is essential. We studied how Akt1 deletion in PC3 and DU145 cells activates the Nodal pathway and promotes PCa epithelial-to-mesenchymal transition (EMT) and metastasis. Here we show that Akt1 loss increases Nodal expression in PCa cells accompanied by activation of FoxO1/3a, and EMT markers Snail and N-cadherin as well as loss of epithelial marker E-cadherin. Treatment with FoxO inhibitor AS1842856 abrogated the Nodal expression in Akt1 deleted PCa cells. Akt1 deficient PCa cells exhibited enhanced cell migration and invasion in vitro and lung metastasis in vivo, which were attenuated by treatment with Nodal pathway inhibitor SB505124. Interestingly, Nodal mRNA analysis from two genomic studies in cBioportal showed a positive correlation between Nodal expression and Gleason score indicating the positive role of Nodal in human mPCa. Collectively, our data demonstrate Akt1-FoxO3a-Nodal pathway as an important mediator of PCa metastasis and present Nodal as a potential target to treat mPCa patients.

Nodal increases the malignancy of childhood neuroblastoma cells via regulation of Zeb1

Neuroblastoma (NB) is one of the most common malignant tumors derived from pluripotent cells of the neural crest. Nodal is an important embryonic morphogen which can re-express in cancer cells. The roles of Nodal in the progression of NB are not illustrated. Our present study reveals that Nodal is upregulated in NB cells and tissues. Targeted inhibition of Nodal can suppress the in vitro migration and invasion of NB cells while increase its chemo-sensitivity to doxorubicin (Dox) treatment. Nodal positively regulates the expression of Zeb1, one well-known transcription factors of epithelial to mesenchymal transition (EMT) of cancer cells. Knockdown of Zeb1 can attenuate Nodal-induced malignancy of NB cells. Mechanistically, Nodal increases the protein stability of Zeb1 while has no effect on its mRNA expression. It is due to that Nodal can increase the expression of Ataxia telangiectasia mutated kinase (ATM), which can phosphorylate and stabilize Zeb1 in cancer cells. Collectively, our data revealed that Nodal can increase the malignancy of NB cells via increasing the expression of Zeb1. It suggests that targeted inhibition of Nodal might be a potential therapy approach for NB treatment. © 2019 BioFactors, 45(3):355-363, 2019.

SMAD signaling promotes melanoma metastasis independently of phenotype switching

The development of metastatic melanoma is thought to require the dynamic shifting of neoplastic cells between proliferative and invasive phenotypes. Contrary to this conventional "phenotype switching" model, we now show that disease progression can involve malignant melanoma cells simultaneously displaying proliferative and invasive properties. Using a genetic mouse model of melanoma in combination with in vitro analyses of melanoma cell lines, we found that conditional deletion of the downstream signaling molecule Smad4, which abrogates all canonical TGF-β signaling, indeed inhibits both tumor growth and metastasis. Conditional deletion of the inhibitory signaling factor Smad7, however, generated cells that are both highly invasive and proliferative, indicating that invasiveness is compatible with a high proliferation rate. In fact, conditional Smad7 deletion led to sustained melanoma growth and at the same time promoted massive metastasis formation, a result consistent with data indicating that low SMAD7 levels in patient tumors are associated with a poor survival. Our findings reveal that modulation of SMAD7 levels can overcome the need for phenotype switching during tumor progression and may thus represent a novel therapeutic target in metastatic disease.

Nodal Promotes the Migration and Invasion of Bladder Cancer Cells via Regulation of Snail

Urinary bladder cancer is one of commonly diagnosed malignancies worldwide, especially in males. Understanding the mechanisms of advanced metastasis in bladder cell is important for therapy and drug development. Nodal, an important embryonic morphogen, has been reported to modulate tumorigenesis. We found that the expression of Nodal was upregulated in bladder cancer cells and tissues as compared to their corresponding controls. Knockdown of Nodal can suppress the migration, invasion, and epithelial-to-mesenchymal transition (EMT) of bladder cancer cells. Nodal can positively regulate the expression of Snail, one powerful EMT transcription factors, in bladder cancer cells. Overexpression of Snail can attenuate the si-Nodal suppressed cell migration and invasion. Nodal can increase the transcription and protein stability of Snail in bladder cancer cells. YY1, which can be activated by Nodal, is responsible for Nodal induced transcription of Snail. ATM, which can stabilize Snail by phosphorylation on Serine-100, was involved in Nodal upregulated protein stability of Snail. Collectively, our data showed that Nodal can trigger the malignancy of bladder cancer cells via increasing the transcription and protein stability of Snail. It indicated that Nodal might be a potential therapeutic target for bladder cancer treatment.

High expression of CCR5 in melanoma enhances epithelial-mesenchymal transition and metastasis via TGFβ1

Chemokine receptors are highly expressed in various cancers and play crucial roles in tumor progression. However, their expression patterns and functions in melanoma are unclear. The present study aimed to identify the chemokine receptors that play critical roles in melanoma progression and unravel the underlying molecular mechanisms. We found that CCR5 was more abundant in melanoma cells than normal cells and was positively associated with tumor malignancy in clinical patients. Animal experiments suggested that CCR5 deficiency in B16/F10 or A375 cells suppressed primary tumor growth and lung metastasis, whereas CCR5 overexpression in B16/F0 cells enhanced primary tumor growth and lung metastasis. CCR5 played a critical role in proliferation and migration of melanoma cells in vitro. Importantly, CCR5 was required for maintenance of the mesenchymal phenotype of metastatic melanoma cells. Mechanistically, CCR5 positively regulated expression of TGFβ1, which in turn induced epithelial-mesenchymal transition and migration via PI3K/AKT/GSK3β signaling. Collectively, our results establish a critical role of CCR5 expressed by melanoma cells in cancer progression and reveal the novel mechanisms controlling this process, which suggests the prognostic value of CCR5 in melanoma patients and provides novel insights into CCR5-targeted strategies for melanoma treatment. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Nodal signaling promotes vasculogenic mimicry formation in breast cancer via the Smad2/3 pathway

Vasculogenic mimicry (VM) is a nonangiogenesis-dependent pathway that promotes tumor growth and disease progression. Nodal signaling has several vital roles in both embryo development and cancer progression. However, the effects of Nodal signaling on VM formation in breast cancer and its underlying mechanisms are ill-defined. We analyzed the relationship between Nodal signaling and VM formation in one hundred human breast cancer cases and the results showed that the expression of Nodal was significantly correlated with VM formation, tumor metastasis, differentiation grade, TNM stage and poor prognosis. Furthermore, up-regulation of Nodal expression promoted VM formation of breast cancer cells in vitro and in vivo. Knockdown of Nodal expression restrained VM formation. In addition, Nodal induced EMT and up-regulated the expression of Slug, Snail and c-Myc. We found that blocking the Smad2/3 pathway by administering SB431542 inhibited VM formation in breast cancer cell lines and xenografts. Taken together, Nodal signaling through the Smad2/3 pathway up-regulated Slug, Snail and c-Myc to induce EMT, thereby promoting VM formation. Our study suggests that the Nodal signaling pathway may serve as a therapeutic target to inhibit VM formation and improve prognosis in breast cancer patients.

The EMT-related transcription factor snail up-regulates FAPα in malignant melanoma cells

FAPα is a cell surface serine protease, mainly expressed in tumor stromal fibroblasts in more than 90% of human epithelial carcinomas. Due to its almost no expression in normal tissues and its tumor-promoting effects, FAPα has been studied as a novel potential target for antitumor therapy. However, the regulation mechanism on FAPα expression is poorly understood. In this study, we found that overexpression of snail significantly increased the mRNA and protein expression levels of FAPα in malignant melanoma B16 and SK-MEL-28 cells. Overexpression of snail increased FAPα promoter activity remarkably. Snail could directly bind to FAPα promoter to regulate FAPα expression. Moreover, snail expression was positively correlated to FAPα expression in human cutaneous malignant melanoma. Furthermore, knockdown of FAPα markedly reduced snail-induced cell migration. Overall, our findings provide a novel regulation mechanism on FAPα expression and highlight the role of snail/FAPα axis as a novel target for melanoma treatment.

Identifying and targeting determinants of melanoma cellular invasion

Epithelial-to-mesenchymal transition is a critical process that increases the malignant potential of melanoma by facilitating invasion and dissemination of tumor cells. This study identified genes involved in the regulation of cellular invasion and evaluated whether they can be targeted to inhibit melanoma invasion. We identified Peroxidasin (PXDN), Netrin 4 (NTN4) and GLIS Family Zinc Finger 3 (GLIS3) genes consistently elevated in invasive mesenchymal-like melanoma cells. These genes and proteins were highly expressed in metastatic melanoma tumors, and gene silencing led to reduced melanoma invasion in vitro. Furthermore, migration of PXDN, NTN4 or GLIS3 siRNA transfected melanoma cells was inhibited following transplantation into the embryonic chicken neural tube compared to control siRNA transfected melanoma cells. Our study suggests that PXDN, NTN4 and GLIS3 play a functional role in promoting melanoma cellular invasion, and therapeutic approaches directed toward inhibiting the action of these proteins may reduce the incidence or progression of metastasis in melanoma patients.

Epithelial-to-Mesenchymal Transition in the Female Reproductive Tract: From Normal Functioning to Disease Pathology

Epithelial-to-mesenchymal transition (EMT) is a physiological process that is vital throughout the human lifespan. In addition to contributing to the development of various tissues within the growing embryo, EMT is also responsible for wound healing and tissue regeneration later in adulthood. In this review, we highlight the importance of EMT in the development and normal functioning of the female reproductive organs (the ovaries and the uterus) and describe how dysregulation of EMT can lead to pathological conditions, such as endometriosis, adenomyosis, and carcinogenesis. We also summarize the current literature relating to EMT in the context of ovarian and endometrial carcinomas, with a particular focus on how molecular mechanisms and the tumor microenvironment can govern cancer cell plasticity, therapy resistance, and metastasis.

Plasticity underlies tumor progression: role of Nodal signaling

The transforming growth factor beta (TGFβ) superfamily member Nodal is an established regulator of early embryonic development, with primary roles in endoderm induction, left-right asymmetry, and primitive streak formation. Nodal signals through TGFβ family receptors at the plasma membrane and induces signaling cascades leading to diverse transcriptional regulation. While conceptually simple, the regulation of Nodal and its molecular effects are profoundly complex and context dependent. Pioneering work by developmental biologists has characterized the signaling pathways, regulatory components, and provided detailed insight into the mechanisms by which Nodal mediates changes at the cellular and organismal levels. Nodal is also an important factor in maintaining pluripotency of embryonic stem cells through regulation of core transcriptional programs. Collectively, this work has led to an appreciation for Nodal as a powerful morphogen capable of orchestrating multiple cellular phenotypes. Although Nodal is not active in most adult tissues, its reexpression and signaling have been linked to multiple types of human cancer, and Nodal has emerged as a driver of tumor growth and cellular plasticity. In vitro and in vivo experimental evidence has demonstrated that inhibition of Nodal signaling reduces cancer cell aggressive characteristics, while clinical data have established associations with Nodal expression and patient outcomes. As a result, there is great interest in the potential targeting of Nodal activity in a therapeutic setting for cancer patients that may provide new avenues for suppressing tumor growth and metastasis. In this review, we evaluate our current understanding of the complexities of Nodal function in cancer and highlight recent experimental evidence that sheds light on the therapeutic potential of its inhibition.

Glucocorticoid receptor-mediated delivery of nano gold-withaferin conjugates for reversal of epithelial-to-mesenchymal transition and tumor regression

AIM

To explore the potential of glucocorticoid receptor-targeted nano-gold formulation as antitumor drug sensitizing agent.

MATERIALS & METHODS

Simultaneous conjugation of gold nanoparticle with thiol-modified dexamethasone, a synthetic glucocorticoid and anticancer drug withaferin A afforded stable gold nanoparticle-modifed dexamethasone-withaferin A nanoconjugate.

RESULTS

This metallic nanoparticle formulation showed glucocorticoid receptor-dependent cancer cell selective cytotoxicity, inhibited growth of aggressive mouse melanoma tumor, reduced mice mortality, while reversing epithelial-to-mesenchymal transition in tumor cells. Same treatment also leads to near-complete downregulation of ABCG2 drug transporter in tumor-associated cells thus attributing it to its drug sensitizing ability.

CONCLUSION

The presently synthesized nanoconjugate holds a great promise to sensitize cancer cells to chemotherapeutics and induce epithelial-to-mesenchymal transition reversal in tumor cells preventing metastasis.

CCL21 Facilitates Chemoresistance and Cancer Stem Cell-Like Properties of Colorectal Cancer Cells through AKT/GSK-3β/Snail Signals

Some evidence indicated that chemoresistance associates with the acquisition of cancer stem-like properties. Recent studies suggested that chemokines can promote the chemoresistance and stem cell properties in various cancer cells, while the underling mechanism is still not completely illustrated. In our study, we found that CCL21 can upregulate the expression of P-glycoprotein (P-gp) and stem cell property markers such as Bmi-1, Nanog, and OCT-4 in colorectal cancer (CRC) HCT116 cells and then improve the cell survival rate and mammosphere formation. Our results suggested that Snail was crucial for CCL21-mediated chemoresistance and cancer stem cell property in CRC cells. Further, we observed that CCL21 treatment increased the protein but not mRNA levels of Snail, which suggested that CCL21 upregulates Snail via posttranscriptional ways. The downstream signals AKT/GSK-3β mediated CCL21 induced the upregulation of Snail due to the fact that CCL21 treatment can obviously phosphorylate both AKT and GSK-3β. The inhibitor of PI3K/Akt, LY294002 significantly abolished CCL21 induced chemoresistance and mammosphere formation of HCT116 cells. Collectively, our results in the present study revealed that CCL21 can facilitate chemoresistance and stem cell property of CRC cells via the upregulation of P-gp, Bmi-1, Nanog, and OCT-4 through AKT/GSK-3β/Snail signals, which suggested a potential therapeutic approach to CRC patients.

Snail Is a Critical Mediator of Invadosome Formation and Joint Degradation in Arthritis

Progressive cartilage destruction, mediated by invasive fibroblast-like synoviocytes, is a central feature in the pathogenesis of rheumatoid arthritis (RA). Members of the Snail family of transcription factors are required for cell migration and invasion, but their role in joint destruction remains unknown. Herein, we demonstrate that Snail is essential for the formation of extracellular matrix-degrading invadosomal structures by synovial cells from collagen-induced arthritis (CIA) rats and RA patients. Mechanistically, Snail induces extracellular matrix degradation in synovial cells by repressing PTEN, resulting in increased phosphorylation of platelet-derived growth factor receptor and activation of the phosphatidylinositol 3-kinase/AKT pathway. Of significance, Snail is overexpressed in synovial cells and tissues of CIA rats and RA patients, whereas knockdown of Snail in CIA joints prevents cartilage invasion and joint damage. Furthermore, Snail expression is associated with an epithelial-mesenchymal transition gene signature characteristic of transglutaminase 2/transforming growth factor-β activation. Transforming growth factor-β and transglutaminase 2 stimulate Snail-dependent invadosome formation in rat and human synoviocytes. Our results identify the Snail-PTEN platelet-derived growth factor receptor/phosphatidylinositol 3-kinase axis as a novel regulator of the prodestructive invadosome-forming phenotype of synovial cells. New therapies for RA target inflammation, and are only partly effective in preventing joint damage. Blocking Snail and/or its associated gene expression program may provide an additional tool to improve the efficacy of treatments to prevent joint destruction.

Overexpression of Nodal induces a metastatic phenotype in pancreatic cancer cells via the Smad2/3 pathway

Metastasis is the major cause for the high mortality rate of pancreatic cancer. Human embryonic stem cell (hESC) associated genes frequently correlate with malignant disease progression. Recent studies have demonstrated that the embryonic protein Nodal, which plays a critical role during embryonic development, is re-expressed in several types of tumors and promotes cancers progression. However, little is known about the role of Nodal in pancreatic cancer. Here, we show that Nodal expression is upregulated in human pancreatic cancer tissues. Moreover, Nodal expression levels correlate well with the grade of pancreatic cancer differentiation. In addition, we present clear evidence that Nodal induces signal transduction through the Smad2/3-dependent pathway in vitro. Furthermore, we show that Nodal promotes pancreatic cancer cell migration and invasion, induces epithelial-mesenchymal transition (EMT) and enhances the expression of matrix metalloproteinase-2 (MMP2) and CXC chemokine receptor 4 (CXCR4). Using an in vivo liver metastasis model of pancreatic cancer, we observed that blocking Nodal signaling activity with the small-molecule inhibitor SB431542 decreases the number and size of liver metastases. Taken together, our results suggest that Nodal overexpression induces a metastatic phenotype in pancreatic cancer cells, and that targeting Nodal signaling may be a promising therapeutic strategy for pancreatic cancer.

Loss of ATM accelerates pancreatic cancer formation and epithelial-mesenchymal transition

Pancreatic ductal adenocarcinoma (PDAC) is associated with accumulation of particular oncogenic mutations and recent genetic sequencing studies have identified ataxia telangiectasia-mutated (ATM) mutations in PDAC cohorts. Here we report that conditional deletion of ATM in a mouse model of PDAC induces a greater number of proliferative precursor lesions coupled with a pronounced fibrotic reaction. ATM-targeted mice display altered TGFβ-superfamily signalling and enhanced epithelial-to-mesenchymal transition (EMT) coupled with shortened survival. Notably, our mouse model recapitulates many features of more aggressive human PDAC subtypes. Particularly, we report that low expression of ATM predicts EMT, a gene signature specific for Bmp4 signalling and poor prognosis in human PDAC. Our data suggest an intimate link between ATM expression and pancreatic cancer progression in mice and men.

Embryonic Chicken Transplantation is a Promising Model for Studying the Invasive Behavior of Melanoma Cells

Epithelial-to-mesenchymal transition is a hallmark event in the metastatic cascade conferring invasive ability to tumor cells. There are ongoing efforts to replicate the physiological events occurring during mobilization of tumor cells in model systems. However, few systems are able to capture these complex in vivo events. The embryonic chicken transplantation model has emerged as a useful system to assess melanoma cells including functions that are relevant to the metastatic process, namely invasion and plasticity. The chicken embryo represents an accessible and economical 3-dimensional in vivo model for investigating melanoma cell invasion as it exploits the ancestral relationship between melanoma and its precursor neural crest cells. We describe a methodology that enables the interrogation of melanoma cell motility within the developing avian embryo. This model involves the injection of melanoma cells into the neural tube of chicken embryos. Melanoma cells are labeled using fluorescent tracker dye, Vybrant DiO, then cultured as hanging drops for 24 h to aggregate the cells. Groups of approximately 700 cells are placed into the neural tube of chicken embryos prior to the onset of neural crest migration at the hindbrain level (embryonic day 1.5) or trunk level (embryonic day 2.5). Chick embryos are reincubated and analyzed after 48 h for the location of melanoma cells using fluorescent microscopy on whole mounts and cross-sections of the embryos. Using this system, we compared the in vivo invasive behavior of epithelial-like and mesenchymal-like melanoma cells. We report that the developing embryonic microenvironment confers motile abilities to both types of melanoma cells. Hence, the embryonic chicken transplantation model has the potential to become a valuable tool for in vivo melanoma invasion studies. Importantly, it may provide novel insights into and reveal previously unknown mediators of the metastatic steps of invasion and dissemination in melanoma.

Human Cerberus prevents nodal-receptor binding, inhibits nodal signaling, and suppresses nodal-mediated phenotypes

The Transforming Growth Factor-ß (TGFß) family ligand Nodal is an essential embryonic morphogen that is associated with progression of breast and other cancers. It has therefore been suggested that Nodal inhibitors could be used to treat breast cancers where Nodal plays a defined role. As secreted antagonists, such as Cerberus, tightly regulate Nodal signaling during embryonic development, we undertook to produce human Cerberus, characterize its biochemical activities, and determine its effect on human breast cancer cells. Using quantitative methods, we investigated the mechanism of Nodal signaling, we evaluated binding of human Cerberus to Nodal and other TGFß family ligands, and we characterized the mechanism of Nodal inhibition by Cerberus. Using cancer cell assays, we examined the ability of Cerberus to suppress aggressive breast cancer cell phenotypes. We found that human Cerberus binds Nodal with high affinity and specificity, blocks binding of Nodal to its signaling partners, and inhibits Nodal signaling. Moreover, we showed that Cerberus profoundly suppresses migration, invasion, and colony forming ability of Nodal expressing and Nodal supplemented breast cancer cells. Taken together, our studies provide mechanistic insights into Nodal signaling and Nodal inhibition with Cerberus and highlight the potential value of Cerberus as anti-Nodal therapeutic.

PI3K signalling is required for a TGFβ-induced epithelial-mesenchymal-like transition (EMT-like) in human melanoma cells

Epithelial to mesenchymal transition (EMT) is a programme defined in epithelial cells and recognized as playing a critical role in cancer progression. Although melanoma is not a cancer of epithelial cells, hallmarks of EMT have been described to play a critical role in melanoma progression. Here, we demonstrate that long-term TGFβ exposure can induce a dedifferentiated EMT-like state resembling a previously described invasive phenotype (EMT-like). TGFβ-induced EMT-like is marked by the downregulation of melanocyte differentiation markers, such as MITF, and the upregulation of mesenchymal markers, such as N-cadherin, and an increase in melanoma cell migration and cell invasion. Pharmacological interference shows the dependency of TGFβ-induced EMT-like on the activation of the PDGF signalling pathway and the subsequent activation of PI3K in human melanoma cells. Together, the data provide novel insights into the transcriptional plasticity of melanoma cells that might contribute to tumor progression in patients and propose avenues to therapeutic interventions.

The reversal effects of 3-bromopyruvate on multidrug resistance in vitro and in vivo derived from human breast MCF-7/ADR cells

Purpose

P-glycoprotein mediated efflux is one of the main mechanisms for multidrug resistance in cancers, and 3-Bromopyruvate acts as a promising multidrug resistance reversal compound in our study. To test the ability of 3-Bromopyruvate to overcome P-glycoprotein-mediated multidrug resistance and to explore its mechanisms of multidrug resistance reversal in MCF-7/ADR cells, we evaluate the in vitro and in vivo modulatory activity of this compound.

Methods

The in vitro and in vivo activity was determined using the MTT assay and human breast cancer xenograft models. The gene and protein expression of P-glycoprotein were determined using real-time polymerase chain reaction and the Western blotting technique, respectively. ABCB-1 bioactivity was tested by fluorescence microscopy, multi-mode microplate reader, and flow cytometry. The intracellular levels of ATP, HK-II, and ATPase activity were based on an assay kit according to the manufacturer’s instructions.

Results

3-Bromopyruvate treatment led to marked decreases in the IC₅₀ values of selected chemotherapeutic drugs [e.g., doxorubicin (283 folds), paclitaxel (85 folds), daunorubicin (201 folds), and epirubicin (171 folds)] in MCF-7/ADR cells. 3-Bromopyruvate was found also to potentiate significantly the antitumor activity of epirubicin against MCF-7/ADR xenografts. The intracellular level of ATP decreased 44%, 46% in the presence of 12.5.25 µM 3-Bromopyruvate, whereas the accumulation of rhodamine 123 and epirubicin (two typical P-glycoprotein substrates) in cells was significantly increased. Furthermore, we found that the mRNA and the total protein level of P-glycoprotein were slightly altered by 3-Bromopyruvate. Moreover, the ATPase activity was significantly inhibited when 3-Bromopyruvate was applied.

Conclusion

We demonstrated that 3-Bromopyruvate can reverse P-glycoprotein-mediated efflux in MCF-7/ADR cells. Multidrug resistance reversal by 3-Bromopyruvate occurred through at least three approaches, namely, a decrease in the intracellular level of ATP and HK-II bioactivity, the inhibition of ATPase activity, and the slight decrease in P-glycoprotein expression in MCF-7/ADR cells.

Snail regulated by PKC/GSK-3β pathway is crucial for EGF-induced epithelial-mesenchymal transition (EMT) of cancer cells

Cancer metastasis is considered a major challenge in cancer therapy. Recently, epidermal growth factor (EGF)/epidermal growth factor receptor (EGFR) signaling has been shown to induce epithelial-mesenchymal transition (EMT) and thereby to promote cancer metastasis. However, the underlying mechanism has not been fully elucidated. We demonstrate that EGF can induce EMT in human prostate and lung cancer cells and thus promote invasion and migration. EGF-induced EMT has been characterized by the cells acquiring mesenchymal spindle-like morphology and increasing their expression of N-cadherin and fibronectin, with a concomitant decrease of E-cadherin. Both protein and mRNA expression of transcription factor Snail rapidly increases after EGF treatment. The knockdown of Snail significantly attenuates EGF-induced EMT, suggesting that Snail is crucial for this process. To determine the way that Snail is accumulated, we demonstrate (1) that EGF promotes the stability of Snail via inhibiting the activity of glycogen synthase kinase 3 beta (GSK-3β), (2) that protein kinase C (PKC) rather than the phosphatidylinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway is responsible for GSK-3β inhibition and (3) that GSK-3β inhibition promotes the transcription of Snail. Taken together, these results reveal that the PKC/GSK-3β signaling pathway controls both the stability and transcription of Snail, which is crucial for EMT induced by EGF in PC-3 and A549 cells. Our study suggests a novel signaling pathway for Snail regulation and provides a better understanding of growth-factor-induced tumor EMT and metastasis.

AKT/GSK-3β regulates stability and transcription of snail which is crucial for bFGF-induced epithelial-mesenchymal transition of prostate cancer cells

BACKGROUND

Epithelial-mesenchymal transition (EMT) plays a pivotal role in the development of metastatic cancers. Basic fibroblast growth factor (bFGF) is significantly elevated in metastatic prostate cancers, which has been mentioned mainly to induce EMT in normal cells. However, there is no description about bFGF induced EMT and its underlying mechanism in prostate cancer cells.

METHODS

Western blotting, immunofluorescence and qRT-PCR assays were used to study protein or mRNA expression profiles of the EMT. Wound healing scratch, migration and invasion assays were used to test the motility of cells undergoing EMT. More methods were used to explore the underlying mechanisms.

RESULTS

We demonstrated that bFGF promoted EMT and motility of human prostate cancer PC-3 cells. Both protein and mRNA expression of Snail were rapidly increased after bFGF treatment. Ectopic expression of Snail triggered EMT and enhanced cell motility in PC-3 cells, and knockdown of Snail almost abolished bFGF induced EMT, suggesting the critical role of Snail. Mechanistic study demonstrated that bFGF promoted the stability, nuclear localization and transcription of Snail by inhibiting the activity of glycogen synthase kinase 3 beta (GSK-3β) through phosphatidylinositide 3 kinases (PI3K)/protein kinase B (AKT) signaling pathway.

CONCLUSIONS

It is concluded that bFGF can promote EMT and motility of PC-3 cells, and AKT/GSK-3β signaling pathway controls the stability, localization and transcription of Snail which is crucial for this bFGF induced EMT.

GENERAL SIGNIFICANCE

To our knowledge, this is the first study to demonstrate that bFGF can induce EMT via AKT/GSK-3β/Snail signaling pathway in prostate cancer cells.