Phosphorylation of serine 367 of FOXC2 by p38 regulates ZEB1 and breast cancer metastasis, without impacting primary tumor growth

Nasopharyngeal carcinoma: current views on the tumor microenvironment's impact on drug resistance and clinical outcomes

The incidence of nasopharyngeal carcinoma (NPC) exhibits significant variations across different ethnic groups and geographical regions, with Southeast Asia and North Africa being endemic areas. Of note, Epstein-Barr virus (EBV) infection is closely associated with almost all of the undifferentiated NPC cases. Over the past three decades, radiation therapy and chemotherapy have formed the cornerstone of NPC treatment. However, recent advancements in immunotherapy have introduced a range of promising approaches for managing NPC. In light of these developments, it has become evident that a deeper understanding of the tumor microenvironment (TME) is crucial. The TME serves a dual function, acting as a promoter of tumorigenesis while also orchestrating immunosuppression, thereby facilitating cancer progression and enabling immune evasion. Consequently, a comprehensive comprehension of the TME and its intricate involvement in the initiation, progression, and metastasis of NPC is imperative for the development of effective anticancer drugs. Moreover, given the complexity of TME and the inter-patient heterogeneity, personalized treatment should be designed to maximize therapeutic efficacy and circumvent drug resistance. This review aims to provide an in-depth exploration of the TME within the context of EBV-induced NPC, with a particular emphasis on its pivotal role in regulating intercellular communication and shaping treatment responses. Additionally, the review offers a concise summary of drug resistance mechanisms and potential strategies for their reversal, specifically in relation to chemoradiation therapy, targeted therapy, and immunotherapy. Furthermore, recent advances in clinical trials pertaining to NPC are also discussed.

Spatial and Temporal Relationship between Epithelial-Mesenchymal Transition (EMT) and Stem Cells in Cancer

BACKGROUND

Epithelial-mesenchymal transition (EMT) is often linked with carcinogenesis. However, EMT is also important for embryo development and only reactivates in cancer. Connecting how EMT occurs during embryonic development and in cancer could help us further understand the root mechanisms of cancer diseases.

CONTENT

There are key regulatory elements that contribute to EMT and the induction and maintenance of stem cell properties during embryogenesis, tissue regeneration, and carcinogenesis. Here, we explore the implications of EMT in the different stages of embryogenesis and tissue development. We especially highlight the necessity of EMT in the mesodermal formation and in neural crest cells. Through EMT, these cells gain epithelial-mesenchymal plasticity (EMP). With this transition, crucial morphological changes occur to progress through the metastatic cascade as well as tissue regeneration after an injury. Stem-like cells, including cancer stem cells, are generated from EMT and during this process upregulate factors necessary for stem cell maintenance. Hence, it is important to understand the key regulators allowing stem cell awakening in cancer, which increases plasticity and promotes treatment resistance, to develop strategies targeting this cell population and improve patient outcomes.

SUMMARY

EMT involves multifaceted regulation to allow the fluidity needed to facilitate adaptation. This regulatory mechanism, plasticity, involves many cooperating transcription factors. Additionally, posttranslational modifications, such as splicing, activate the correct isoforms for either epithelial or mesenchymal specificity. Moreover, epigenetic regulation also occurs, such as acetylation and methylation. Downstream signaling ultimately results in the EMT which promotes tissue generation/regeneration and cancer progression.

Doxorubicin as a Potential Treatment Option in Canine Mammary Tumors

Canine mammary tumors represent one of the leading malignant pathologies in female dogs, displaying the importance of efficient therapeutic findings, besides the golden-standard surgery, able to limit the development of the disease. Studies in human cancers demonstrated that Doxorubicin presents a good effect in different biological processes like apoptosis, autophagy, the cell cycle, cell invasion, and the epithelial-to-mesenchymal transition. This study followed the effects of Doxorubicin on two canine mammary cancer cell lines P114 and CMT-U27. Doxorubicin treatment in both cell lines shows an inhibitory effect in cell proliferation and an alteration in expression of the EMT-related genes. The obtained results provide valuable information for revealing the link between Doxorubicin, phenotypic changes, and proliferation dynamics in canine mammary tumor models.

MicroRNA-155 and cancer metastasis: Regulation of invasion, migration, and epithelial-to-mesenchymal transition

Among the leading causes of death globally has been cancer. Nearly 90% of all cancer-related fatalities are attributed to metastasis, which is the growing of additional malignant growths out of the original cancer origin. Therefore, a significant clinical need for a deeper comprehension of metastasis exists. Beginning investigations are being made on the function of microRNAs (miRNAs) in the metastatic process. Tiny non-coding RNAs called miRNAs have a crucial part in controlling the spread of cancer. Some miRNAs regulate migration, invasion, colonization, cancer stem cells' properties, the epithelial-mesenchymal transition (EMT), and the microenvironment, among other processes, to either promote or prevent metastasis. One of the most well-conserved and versatile miRNAs, miR-155 is primarily distinguished by overexpression in a variety of illnesses, including malignant tumors. It has been discovered that altered miR-155 expression is connected to a number of physiological and pathological processes, including metastasis. As a result, miR-155-mediated signaling pathways were identified as possible cancer molecular therapy targets. The current research on miR-155, which is important in controlling cancer cells' invasion, and metastasis as well as migration, will be summarized in the current work. The crucial significance of the lncRNA/circRNA-miR-155-mRNA network as a crucial regulator of carcinogenesis and a player in the regulation of signaling pathways or related genes implicated in cancer metastasis will be covered in the final section. These might provide light on the creation of fresh treatment plans for controlling cancer metastasis.

Homology modeling of Forkhead box protein C2: identification of potential inhibitors using ligand and structure-based virtual screening

Overexpression of Forkhead box protein C2 (FOXC2) has been associated with different types of carcinomas. FOXC2 plays an important role in the initiation and maintenance of the epithelial-mesenchymal transition (EMT) process, which is essential for the development of higher-grade tumors with an enhanced ability for metastasis. Thus, FOXC2 has become a therapeutic target for the development of anticancer drugs. MC-1-F2, the only identified experimental inhibitor of FOXC2, interacts with the full length of FOXC2. However, only the DNA-binding domain (DBD) of FOXC2 has resolved crystal structure. In this work, a three-dimensional (3D) structure of the full-length FOXC2 using homology modeling was developed and used for structure-based drug design (SBDD). The quality of this 3D model of the full-length FOXC2 was evaluated using MolProbity, ERRAT, and ProSA modules. Molecular dynamics (MD) simulation was also carried out to verify its stability. Ligand-based drug design (LBDD) was carried out to identify similar analogues for MC-1-F2 against 15 million compounds from ChEMBL and ZINC databases. 792 molecules were retrieved from this similarity search. De novo SBDD was performed against the full-length 3D structure of FOXC2 through homology modeling to identify novel inhibitors. The combination of LBDD and SBDD helped in gaining a better insight into the binding of MC-1-F2 and its analogues against the full length of the FOXC2. The binding free energy of the top hits was further investigated using MD simulations and MM/GBSA calculations to result in eight promising hits as lead compounds targeting FOXC2.

MAPKs in the early steps of senescence implemEMTation

Evidence is accumulating that the earliest stages of the DNA damage response can direct cells toward senescence instead of other cell fates. In particular, tightly regulated signaling through Mitogen-Activated Protein Kinases (MAPKs) in early senescence can lead to a sustained pro-survival program and suppress a pro-apoptotic program. Importantly, an epithelial-to-mesenchymal Transition (EMT)-like program appears essential for preventing apoptosis and favoring senescence following DNA damage. In this review, we discuss how MAPKs might influence EMT features to promote a senescent phenotype that increases cell survival at the detriment of tissue function.

Mechanisms of cancer metastasis

Metastatic cancer is almost always terminal, and more than 90% of cancer deaths result from metastatic disease. Combating cancer metastasis and post-therapeutic recurrence successfully requires understanding each step of metastatic progression. This review describes the current state of knowledge of the etiology and mechanism of cancer progression from primary tumor growth to the formation of new tumors in other parts of the body. Open questions, avenues for future research, and therapeutic approaches with the potential to prevent or inhibit metastasis through personalization to each patient's mutation and/or immune profile are also highlighted.

Oncogenic functions of the FOXC2 transcription factor: a hallmarks of cancer perspective

Epigenetic regulation of gene expression is a fundamental determinant of molecular and cellular function, and epigenetic reprogramming in the context of cancer has emerged as one of the key enabling characteristics associated with acquisition of the core hallmarks of this disease. As such, there has been renewed interest in studying the role of transcription factors as epigenetic regulators of gene expression in cancer. In this review, we discuss the current state of knowledge surrounding the oncogenic functions of FOXC2, a transcription factor that frequently becomes dysregulated in a variety of cancer types. In addition to highlighting the clinical impact of aberrant FOXC2 activity in cancer, we discuss mechanisms by which this transcription factor becomes dysregulated in both tumor and tumor-associated cells, placing particular emphasis on the ways in which FOXC2 promotes key hallmarks of cancer progression. Finally, we bring attention to important issues related to the oncogenic dysregulation of FOXC2 that must be addressed going forward in order to improve our understanding of FOXC2-mediated cancer progression and to guide prognostic and therapeutic applications of this knowledge in clinical settings.

Dysregulated ceramides metabolism by fatty acid 2-hydroxylase exposes a metabolic vulnerability to target cancer metastasis

Whereas it is appreciated that cancer cells rewire lipid metabolism to survive and propagate, the roles of lipid metabolism in metastasis remain largely unknown. In this study, using esophageal squamous cell carcinoma (ESCC) as a pulmonary metastasis model, we find that the enzyme fatty acid 2-hydroxylase (FA2H), which catalyzes the hydroxylation of free fatty acids (FAs), is enriched in a subpopulation of ESCC cells with high metastatic potential, and that FA2H knockdown markedly mitigates metastatic lesions. Moreover, increased FA2H expression is positively associated with poor survival in patients with ESCC. Lipidomics analysis identifies that two dihydroceramides—Cer(d18:0/24:0) and Cer(d18:0/24:1)—are increased in FA2H-depleted metastasizing ESCC cells. Upon administration, Cer(d18:0/24:0) and Cer(d18:0/24:1) impair the formation of overt metastases in a mouse experimental metastasis model. Then, forkhead box protein C2 (FOXC2) and FA2H are found to be co-upregulated in metastatic ESCC cell populations and ESCC specimens, and FA2H expression is further experimentally verified to be transcriptionally induced by FOXC2, which is boosted per se by tumour necrosis factor α (TNFα), a critical pro-metastasis cytokine in the tumour microenvironment, in metastasizing cells. Together, these results demonstrate that TNFα-FOXC2-FA2H is a novel signaling axis to promote metastasis, and its downstream dihydroceramide products could be promising drugs to intervene in metastasis.

Classical epithelial-mesenchymal transition (EMT) and alternative cell death process-driven blebbishield metastatic-witch (BMW) pathways to cancer metastasis

Metastasis is a pivotal event that accelerates the prognosis of cancer patients towards mortality. Therapies that aim to induce cell death in metastatic cells require a more detailed understanding of the metastasis for better mitigation. Towards this goal, we discuss the details of two distinct but overlapping pathways of metastasis: a classical reversible epithelial-to-mesenchymal transition (hybrid-EMT)-driven transport pathway and an alternative cell death process-driven blebbishield metastatic-witch (BMW) transport pathway involving reversible cell death process. The knowledge about the EMT and BMW pathways is important for the therapy of metastatic cancers as these pathways confer drug resistance coupled to immune evasion/suppression. We initially discuss the EMT pathway and compare it with the BMW pathway in the contexts of coordinated oncogenic, metabolic, immunologic, and cell biological events that drive metastasis. In particular, we discuss how the cell death environment involving apoptosis, ferroptosis, necroptosis, and NETosis in BMW or EMT pathways recruits immune cells, fuses with it, migrates, permeabilizes vasculature, and settles at distant sites to establish metastasis. Finally, we discuss the therapeutic targets that are common to both EMT and BMW pathways.

Role of p38 MAP kinase in cancer stem cells and metastasis

Therapeutic resistance and metastatic progression are responsible for the majority of cancer mortalities. In particular, the development of resistance is a significant barrier to the efficacy of cancer treatments such as chemotherapy, radiotherapy, targeted therapies, and immunotherapies. Cancer stem cells (CSCs) underlie treatment resistance and metastasis. p38 mitogen-activated protein kinase (p38 MAPK) is downstream of several CSC-specific signaling pathways, and it plays an important role in CSC development and maintenance and contributes to metastasis and chemoresistance. Therefore, the development of therapeutic approaches targeting p38 can sensitize tumors to chemotherapy and prevent metastatic progression.

Metastasis and MAPK Pathways

Cancer is a leading cause of death worldwide. In many cases, the treatment of the disease is limited due to the metastasis of cells to distant locations of the body through the blood and lymphatic drainage. Most of the anticancer therapeutic options focus mainly on the inhibition of tumor cell growth or the induction of cell death, and do not consider the molecular basis of metastasis. The aim of this work is to provide a comprehensive review focusing on cancer metastasis and the mitogen-activated protein kinase (MAPK) pathway (ERK/JNK/P38 signaling) as a crucial modulator of this process.

Functional Antagonism of Junctional Adhesion Molecule-A (JAM-A), Overexpressed in Breast Ductal Carcinoma In Situ (DCIS), Reduces HER2-Positive Tumor Progression

Simple Summary

Specific drug targets for breast ductal carcinoma in situ (DCIS) remain elusive, despite increasing disease prevalence and burden to healthcare services. Estrogen receptor (ER)-negative HER2-positive DCIS, associated with the poorest patient prognosis, is in particular need of novel therapeutic avenues. This report provides the first evidence that a cell surface protein called JAM-A is upregulated on human DCIS patient tissues and can be readily targeted by a novel JAM-A-binding peptide inhibitor in separate in vivo models of DCIS. The anti-tumor efficacy and lack of systemic toxicity of this lead inhibitor, coupled with early indications of potential signaling pathways implicated, support the value of future studies investigating JAM-A as a novel drug target in DCIS patients.

Abstract

Breast ductal carcinoma in situ (DCIS) is clinically challenging, featuring high diagnosis rates and few targeted therapies. Expression/signaling from junctional adhesion molecule-A (JAM-A) has been linked to poor prognosis in invasive breast cancers, but its role in DCIS is unknown. Since progression from DCIS to invasive cancer has been linked with overexpression of the human epidermal growth factor receptor-2 (HER2), and JAM-A regulates HER2 expression, we evaluated JAM-A as a therapeutic target in DCIS. JAM-A expression was immunohistochemically assessed in patient DCIS tissues. A novel JAM-A antagonist (JBS2) was designed and tested alone/in combination with the HER2 kinase inhibitor lapatinib, using SUM-225 cells in vitro and in vivo as validated DCIS models. Murine tumors were proteomically analyzed. JAM-A expression was moderate/high in 96% of DCIS patient tissues, versus 23% of normal adjacent tissues. JBS2 bound to recombinant JAM-A, inhibiting cell viability in SUM-225 cells and a primary DCIS culture in vitro and in a chick embryo xenograft model. JBS2 reduced tumor progression in in vivo models of SUM-225 cells engrafted into mammary fat pads or directly injected into the mammary ducts of NOD-SCID mice. Preliminary proteomic analysis revealed alterations in angiogenic and apoptotic pathways. High JAM-A expression in aggressive DCIS lesions and their sensitivity to treatment by a novel JAM-A antagonist support the viability of testing JAM-A as a novel therapeutic target in DCIS.

Epithelial Mesenchymal Transition and its transcription factors

Epithelial–mesenchymal transition or EMT is an extremely dynamic process involved in conversion of epithelial cells into mesenchymal cells, stimulated by an ensemble of signaling pathways, leading to change in cellular morphology, suppression of epithelial characters and acquisition of properties such as enhanced cell motility and invasiveness, reduced cell death by apoptosis, resistance to chemotherapeutic drugs etc. Significantly, EMT has been found to play a crucial role during embryonic development, tissue fibrosis and would healing, as well as during cancer metastasis. Over the years, work from various laboratories have identified a rather large number of transcription factors (TFs) including the master regulators of EMT, with the ability to regulate the EMT process directly. In this review, we put together these EMT TFs and discussed their role in the process. We have also tried to focus on their mechanism of action, their interdependency, and the large regulatory network they form. Subsequently, it has become clear that the composition and structure of the transcriptional regulatory network behind EMT probably varies based upon various physiological and pathological contexts, or even in a cell/tissue type-dependent manner.

Nanoliposomal Delivery of MicroRNA-203 Suppresses Migration of Triple-Negative Breast Cancer through Distinct Target Suppression

Triple-negative breast cancers affect thousands of women in the United States and disproportionately drive mortality from breast cancer. MicroRNAs are small, non-coding RNAs that negatively regulate gene expression post-transcriptionally by inhibiting target mRNA translation or by promoting mRNA degradation. We have identified that miRNA-203, silenced by epithelial-mesenchymal transition (EMT), is a tumor suppressor and can promote differentiation of breast cancer stem cells. In this study, we tested the ability of liposomal delivery of miR-203 to reverse aspects of breast cancer pathogenesis using breast cancer and EMT cell lines. We show that translationally relevant methods for increasing miR-203 abundance within a target tissue affects cellular properties associated with cancer progression. While stable miR-203 expression suppresses LASP1 and survivin, nanoliposomal delivery suppresses BMI1, indicating that suppression of distinct mRNA target profiles can lead to loss of cancer cell migration.

Carcinoma cells that have undergone an epithelial-mesenchymal transition differentiate into endothelial cells and contribute to tumor growth

Hypoxia stimulates neoangiogenesis, promoting tumor outgrowth, and triggers the epithelial-mesenchymal transition (EMT), which bestows cells with mesenchymal traits and multi-lineage differentiation potential. Here, we investigated whether EMT can confer endothelial attributes upon carcinoma cells, augmenting tumor growth and vascularization. Following orthotopic implantation of MCF-7 human epithelial breast cancer cells into mice, tumors of different sizes were immunostained for markers of hypoxia and EMT. Larger tumors were well-vascularized with CD31-positive cells of human origin. Hypoxic regions, demarcated by HIF-1α staining, exhibited focal areas of E-cadherin loss and elevated levels of vimentin and the EMT-mediator FOXC2. Implantation of MCF-7 cells, co-mixed with human mammary epithelial (HMLE) cells overexpressing the EMT-inducer Snail, markedly potentiated tumor growth and vascularization, compared with MCF-7 cells injected alone or co-mixed with HMLE-vector cells. Intra-tumoral vessels contained CD31-positive cells derived from either donor cell type. FOXC2 knockdown abrogated the potentiating effects of HMLE-Snail cells on MCF-7 tumor growth and vascularization, and compromised endothelial transdifferentiation of mesenchymal cells cultured in endothelial growth medium. Hence, cells that have undergone EMT can promote tumor growth and neovascularization either indirectly, by promoting endothelial transdifferentiation of carcinoma cells, or directly, by acquiring an endothelial phenotype, with FOXC2 playing key roles in these processes.

Nicotine Synergizes with High-Fat Diet to Induce an Anti-Inflammatory Microenvironment to Promote Breast Tumor Growth

Breast cancer results from a complex interplay of genetics and environment that alters immune and inflammatory systems to promote tumorigenesis. Obesity and cigarette smoking are well-known risk factors associated breast cancer development. Nicotine known to decrease inflammatory signals also modulates immune responses that favor breast cancer development. However, the mechanisms by which nicotine and obesity contribute to breast cancer remain poorly understood. In this study, we examined potential mechanisms by which nicotine (NIC) and high-fat diet (HFD) promote growth of HCC70 and HCC1806 xenografts from African American (AA) triple negative (TN) breast cancer cells. Immunodeficient mice fed on HFD and treated with NIC generated larger HCC70 and HCC1806 tumors when compared to NIC or HFD alone. Increased xenograft growth in the presence of NIC and HFD was accompanied by higher levels of tissue-resident macrophage markers and anti-inflammatory cytokines including IL4, IL13, and IL10. We further validated the involvement of these players by in vitro and ex vivo experiments. We found a proinflammatory milieu with increased expression of IL6 and IL12 in xenografts with HFD. In addition, nicotine or nicotine plus HFD increased a subset of mammary cancer stem cells (MCSCs) and key adipose browning markers CD137 and TMEM26. Interestingly, there was upregulation of stress-induced pp38 MAPK and pERK1/2 in xenografts exposed to HFD alone or nicotine plus HFD. Scratch-wound assay showed marked reduction in proliferation/migration of nicotine and palmitate-treated breast cancer cells with mecamylamine (MEC), a nicotine acetylcholine receptor (nAchR) antagonist. Furthermore, xenograft development in immune-deficient mice, fed HFD plus nicotine, was reduced upon cotreatment with MEC and SB 203580, a pp38MAPK inhibitor. Our study demonstrates the presence of nicotine and HFD in facilitating an anti-inflammatory tumor microenvironment that influences breast tumor growth. This study also shows potential efficacy of combination therapy in obese breast cancer patients who smoke.

Chemotherapy and chemo-resistance in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is closely associated with Epstein-Barr virus (EBV) and occurs frequently in the south of China and Southeast Asian countries. Concurrent chemo-radiotherapy is one of the main treatments for NPC. Although, the combined treatment of chemo-radiotherapy produces a satisfying survival rate, the chemo-resistance arises as a big obstacle in curing recurrent NPC patients. The acquirement of chemo-resistance is usually along with a poor prognosis. So far, the mechanism of chemo-resistance in NPC has not been fully elucidated and there have not been a comprehensive review on this issue. Thus, it is of great significance to summarize the mechanisms involved in NPC chemo-resistance. In this review, the importance and limitations of chemotherapy and the mechanisms of chemo-resistances in NPC were discussed.

Genome-wide gene expression analysis of a murine model of prostate cancer progression: Deciphering the roles of IL-6 and p38 MAPK as potential therapeutic targets

Background

Prostate cancer (PCa) is the most commonly diagnosed cancer and the second leading cause of cancer-related deaths among adult males globally. The poor prognosis of PCa is largely due to late diagnosis of the disease when it has already progressed to an advanced stage marked by androgen-independence, thus necessitating new strategies for early detection and treatment. We construe that these direly needed advances are limited by our poor understanding of early events in the progression of PCa and that would thus represent ideal targets for early intervention. To begin to fill this void, we interrogated molecular “oncophenotypes” that embody the transition of PCa from an androgen-dependent (AD) to–independent (AI) state.

Methods

To accomplish this aim, we used our previously established AD and AI murine PCa cell lines, PLum-AD and PLum-AI, respectively, which recapitulate primary and progressive PCa morphologically and molecularly. We statistically surveyed global gene expressions in these cell lines by microarray analysis. Differential profiles were functionally interrogated by pathways, gene set enrichment and topological gene network analyses.

Results

Gene expression analysis of PLum-AD and PLum-AI transcriptomes (n = 3 each), revealed 723 differentially expressed genes (392 upregulated and 331 downregulated) in PLum-AI compared to PLum-AD cells. Gene set analysis demonstrated enrichment of biological functions and pathways in PLum-AI cells that are central to tumor aggressiveness including cell migration and invasion facilitated by epithelial-to-mesenchymal transition (EMT). Further analysis demonstrated that the p38 mitogen-activated protein kinase (MAPK) was predicted to be significantly activated in the PLum-AI cells, whereas gene sets previously associated with favorable response to the p38 inhibitor SB203580 were attenuated (i.e., inversely enriched) in the PLum-AI cells, suggesting that these aggressive cells may be therapeutically vulnerable to p38 inhibition. Gene set and gene-network analysis also alluded to activation of other signaling networks particularly those associated with enhanced EMT, inflammation and immune function/response including, but not limited to Tnf, IL-6, Mmp 2, Ctgf, and Ptges. Accordingly, we chose SB203580 and IL-6 to validate their effect on PLum-AD and PLum-AI. Some of the common genes identified in the gene-network analysis were validated at the molecular and functional level. Additionally, the vulnerability to SB203580 and the effect of IL-6 were also validated on the stem/progenitor cell population using the sphere formation assay.

Conclusions

In summary, our study highlights pathways associated with an augmented malignant phenotype in AI cells and presents new high-potential targets to constrain the aggressive malignancy seen in the castration-resistant PCa.

FOXC2 is a prognostic biomarker and contributes to the growth and invasion of human hepatocellular carcinoma

Background

Forkhead box C2 (FOXC2) is a crucial factor involving in various cancers. However, its functions in hepatocellular carcinoma (HCC) is unknown. Here, we explored the role of FOXC2 in the progression of HCC and its potential mechanisms.

Methods

FOXC2 expression in HCC tissue and cells were detected by immunohistochemistry or western blot and real-time PCR. CCK8, wound healing and transwell assay were used to measure cell growth and invasion. Tumor formation experiment was carried out to assess the tumorigenicity of HCC cells. Regulation of FOXC2 on Ang-2 was validated by luciferase assay and complementary experiments.

Results

Increased FOXC2 expression was found to be associated positively with more aggressive clinicopathologic features. HCC patients with higher FOXC2 expression had significantly shorter overall survival. FOXC2 expression was indentified as an independent risk factor for resectable HCC. Increased FOXC2 expression accelerated the migration and invasion of HCC cells, accompanied by enhanced Ang-2 expression. Likewise, FOXC2 knockdown yielded opposite results. Moreover, FOXC2 stimulated the activation of the Ang-2 promoter. Suppression of Ang-2 expression hindered the FOXC2-mediated EMT processs, cell migration and invasion of HCC.

Conclusions

FOXC2 is a novel prognostic predictor for HCC and may facilitate the growth and invasion through Ang-2.

Circular RNA PVT1 promotes metastasis via regulating of miR-526b/FOXC2 signals in OS cells

As a class of covalently closed non-coding RNAs, circular RNAs (circRNAs) are key regulators in various malignancies including osteosarcoma (OS). In the present study, we found that circular RNA PVT1 (circPVT1) was up-regulated in OS and correlated with poor prognosis of patients with OS. Functionally, we showed that knockdown of circPVT1 suppressed OS cells metastasis. In addition, we found that (forkhead box C2) FOXC2 was a downstream gene in circPVT1-mediated metastasis in OS cells. We demonstrated that circPVT1 promoted OS cells metastasis via post-transcriptionally regulating of FOXC2. Furthermore, we revealed that microRNA 526b (miR-526b) was a key bridge which connected circPVT1 and FOXC2. We showed that miR-526b was down-regulated in OS tissue and cell lines. Through a transwell assay, we found that miR-526b suppressed OS cells metastasis by targeting of FOXC2. We also showed that miR-526b targeted circPVT1 via similar mircoRNA response elements (MREs) as it did for FOXC2. Finally, we proved that circPVT1 decoyed miR-526b to promote FOXC2-mediated metastasis in OS cells. In brief, our current study demonstrated that circPVT1, functioning as an oncogene, promotes OS cells metastasis via regulation of FOXC2 by acting as a ceRNA of miR-526b. CircPVT1/miR-526b/FOXC2 axis might be a novel target in molecular treatment of OS.

The FOXC2 Transcription Factor Promotes Melanoma Outgrowth and Regulates Expression of Genes Associated With Drug Resistance and Interferon Responsiveness

BACKGROUND/AIM

The FOXC2 transcription factor promotes the progression of several cancer types, but has not been investigated in the context of melanoma cells. To study FOXC2's influence on melanoma progression, we generated a FOXC2-deficient murine melanoma cell line and evaluated The Cancer Genome Atlas (TCGA) patient datasets.

MATERIALS AND METHODS

We compared tumor growth kinetics and RNA-seq/qRT-PCR gene expression profiles from wild-type versus FOXC2-deficient murine melanomas. We also performed Kaplan-Meier survival analysis of TCGA data to assess the influence of FOXC2 gene expression on melanoma patients' response to chemotherapy and immunotherapy.

RESULTS

FOXC2 promotes melanoma progression and regulates the expression of genes associated with multiple oncogenic pathways, including the oxidative stress response, xenobiotic metabolism, and interferon responsiveness. FOXC2 expression in melanoma correlates negatively with patient response to chemotherapy and immunotherapy.

CONCLUSION

FOXC2 drives a tumor-promoting gene expression program in melanoma and is a prognostic indicator of patient response to multiple cancer therapies.

p38-regulated FOXC1 stability is required for colorectal cancer metastasis

Aberrant expression of forkhead box C1 (FOXC1) promotes tumor metastasis in multiple human malignant tumors. However, the upstream modulating mode and downstream molecular mechanism of FOXC1 in metastasis of colorectal cancer (CRC) remain unclear. Herein we describe a systematic analysis of FOXC1 expression and prognosis in CRC performed on our clinical data and public databases, which indicated that FOXC1 upregulation in CRC samples was significantly associated with poor prognosis. FOXC1 knockdown inhibited migration and invasion, whereas FOXC1 overexpression caused the opposite phenotype in vitro and in vivo. Furthermore, MMP10, SOX4 and SOX13 were verified as the target genes of FOXC1 for promoting CRC metastasis. MMP10 was demonstrated as the direct target and mediator of FOXC1. Interestingly, Ser241 and Ser272 of FOXC1 were identified as the key sites to interact with p38 and phosphorylation, which were critically required for maintaining the stability of FOXC1 protein. Moreover, FOXC1 was dephosphorylated by protein phosphatase 2A and phosphorylated by p38, which maintained FOXC1 protein stability through inhibiting ubiquitination. Expression of p38 was correlated with FOXC1 and MMP10 expression, indirectly indicating that FOXC1 was regulated by p38 MAPK. Therefore, FOXC1 is strongly suggested as a pro-metastatic gene in CRC by transcriptionally activating MMP10, SOX4 and SOX13; p38 interacts with and phosphorylates the Ser241 and ser272 sites of FOXC1 to maintain its stability by inhibiting ubiquitination and degradation. In conclusion, the protein stability of FOXC1 mediated by p38 contributes to the metastatic effect in CRC. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

The Epithelial to Mesenchymal Transition Promotes Glutamine Independence by Suppressing GLS2 Expression

Identifying bioenergetics that facilitate the epithelial to mesenchymal transition (EMT) in breast cancer cells may uncover targets to treat incurable metastatic disease. Metastasis is the number one cause of cancer-related deaths; therefore, it is urgent to identify new treatment strategies to prevent the initiation of metastasis. To characterize the bioenergetics of EMT, we compared metabolic activities and gene expression in cells induced to differentiate into the mesenchymal state with their epithelial counterparts. We found that levels of GLS2, which encodes a glutaminase, are inversely associated with EMT. GLS2 down-regulation was correlated with reduced mitochondrial activity and glutamine independence even in low-glucose conditions. Restoration of GLS2 expression in GLS2-negative breast cancer cells rescued mitochondrial activity, enhanced glutamine utilization, and inhibited stem-cell properties. Additionally, inhibition of expression of the transcription factor FOXC2, a critical regulator of EMT in GLS2-negative cells, restored GLS2 expression and glutamine utilization. Furthermore, in breast cancer patients, high GLS2 expression is associated with improved survival. These findings suggest that epithelial cancer cells rely on glutamine and that cells induced to undergo EMT become glutamine independent. Moreover, the inhibition of EMT leads to a GLS2-directed metabolic shift in mesenchymal cancer cells, which may make these cells susceptible to chemotherapies.

UDP-glucose 6-dehydrogenase regulates hyaluronic acid production and promotes breast cancer progression

An improved understanding of the biochemical alterations that accompany tumor progression and metastasis is necessary to inform the next generation of diagnostic tools and targeted therapies. Metabolic reprogramming is known to occur during the epithelial-mesenchymal transition (EMT), a process that promotes metastasis. Here, we identify metabolic enzymes involved in extracellular matrix remodeling that are upregulated during EMT and are highly expressed in patients with aggressive mesenchymal-like breast cancer. Activation of EMT significantly increases production of hyaluronic acid, which is enabled by the reprogramming of glucose metabolism. Using genetic and pharmacological approaches, we show that depletion of the hyaluronic acid precursor UDP-glucuronic acid is sufficient to inhibit several mesenchymal-like properties including cellular invasion and colony formation in vitro, as well as tumor growth and metastasis in vivo. We found that depletion of UDP-glucuronic acid altered the expression of PPAR-gamma target genes and increased PPAR-gamma DNA-binding activity. Taken together, our findings indicate that the disruption of EMT-induced metabolic reprogramming affects hyaluronic acid production, as well as associated extracellular matrix remodeling and represents pharmacologically actionable target for the inhibition of aggressive mesenchymal-like breast cancer progression.

Hypoxia-induced feedback of HIF-1α and lncRNA-CF129 contributes to pancreatic cancer progression through stabilization of p53 protein

Rationale: Emerging evidences have highlighted the critical roles of lncRNAs in human cancer development. The work sought to assess the biological role and potential underlying mechanisms of lncRNA-CF129 (CF129) which is significantly reduced in pancreatic cancer (PC). Methods: CF129 expression and its association with multiple clinicopathologic characteristics in PC specimens were analyzed. The role of CF129 both in vitro and in vivo was assessed, with RNA pull-down and immunoprecipitation assays being performed to detect the interaction between CF129 and p53 and E3 ligase MKRN1. Chromatin immunoprecipitation and luciferase assays were utilized to identify the interaction between p53 and FOXC2 promoter, HIF-1α/HDAC1 complex and CF129 promoter, FOXC2 and HIF-1α promoter, respectively. Results: CF129 levels were markedly lower in PC compared with paired non-tumor adjacent tissues. Low CF129 expression predicted short overall survival in PC patients. CF129 inhibited invasion and metastasis of PC cells in a FOXC2-dependent manner. In addition, CF129 regulates FOXC2 transcription through association with mutant p53. CF129 directly binds to p53 and E3 ligase MKRN1, and such an interaction leading to p53 protein ubiquitination and degradation. Furthermore, CF129 is a hypoxia-responsive lncRNA, which is transcriptionally downregulated by binding between HIF-1α/HDAC1 complex and CF129 promoter. Finally, it is revealed that HIF-1α is reciprocally regulated by FOXC2 in transcriptional level. Clinically, CF129 downregulation coordinates overexpression of FOXC2. Conclusions: Our study suggests that CF129 inhibits pancreatic cell proliferation and invasion by suppression of FOXC2 transcription, which depends on MKRN1-mediated ubiquitin-dependent p53 degradation. The HIF-1α/CF129/ p53/FOXC2 axis may function as a potential biomarker and therapeutic target.

TGF-β-Mediated Epithelial-Mesenchymal Transition and Cancer Metastasis

Transforming growth factor β (TGF-β) is a secreted cytokine that regulates cell proliferation, migration, and the differentiation of a plethora of different cell types. Consistent with these findings, TGF-β plays a key role in controlling embryogenic development, inflammation, and tissue repair, as well as in maintaining adult tissue homeostasis. TGF-β elicits a broad range of context-dependent cellular responses, and consequently, alterations in TGF-β signaling have been implicated in many diseases, including cancer. During the early stages of tumorigenesis, TGF-β acts as a tumor suppressor by inducing cytostasis and the apoptosis of normal and premalignant cells. However, at later stages, when cancer cells have acquired oncogenic mutations and/or have lost tumor suppressor gene function, cells are resistant to TGF-β-induced growth arrest, and TGF-β functions as a tumor promotor by stimulating tumor cells to undergo the so-called epithelial-mesenchymal transition (EMT). The latter leads to metastasis and chemotherapy resistance. TGF-β further supports cancer growth and progression by activating tumor angiogenesis and cancer-associated fibroblasts and enabling the tumor to evade inhibitory immune responses. In this review, we will consider the role of TGF-β signaling in cell cycle arrest, apoptosis, EMT and cancer cell metastasis. In particular, we will highlight recent insights into the multistep and dynamically controlled process of TGF-β-induced EMT and the functions of miRNAs and long noncoding RNAs in this process. Finally, we will discuss how these new mechanistic insights might be exploited to develop novel therapeutic interventions.

FOX-A1 contributes to acquisition of chemoresistance in human lung adenocarcinoma via transactivation of SOX5

Background

Chemoresistance is a major obstacle for the effective treatment of lung adenocarcinoma (LAD). Forkhead box (FOX) proteins have been demonstrated to play critical roles in promoting epithelial-mesenchymal transition (EMT) and chemoresistance. However, whether FOX proteins contribute to the acquisition of EMT and chemoresistance in LAD remains largely unknown.

Methods

FOX-A1 expression was measured in LAD cells and tissues by qRT-PCR. The expression levels of EMT markers were detected by western blotting and immunofluorescence assay. The interaction between Sex determining region Y-box protein 5 (SOX5) and FOX-A1 was validated by chromatin immunoprecipitation sequence (ChIP-seq) and Chromatin immunoprecipitation (ChIP) assay. Kaplan-Meier analysis and multivariate Cox regression analysis were performed to analyze the significance of FOX-A1 and SOX5 expression in the prognosis of LAD patients.

Findings

FOX-A1 was upregulated in docetaxel-resistant LAD cells. High FOX-A1 expression was closely associated with a worse prognosis. Upregulation of FOX-A1 in LAD samples indicated short progression-free survival (PFS) and overall survival (OS). SOX5 is a new and direct target of FOX-A1 and was positively regulated by FOX-A1 in LAD cell lines. Knockdown of FOX-A1 or SOX5 reversed the chemoresistance of docetaxel-resistant LAD cells by suppressing cell proliferation, migration and EMT progress.

Interpretation

These data elucidated an original FOX-A1/SOX5 pathway that represents a promising therapeutic target for chemosensitizing LAD and provides predictive biomarkers for evaluating the efficacy of chemotherapies.

Towards control of cellular decision-making networks in the epithelial-to-mesenchymal transition

We present the epithelial-to-mesenchymal transition (EMT) from two perspectives: experimental/technological and theoretical. We review the state of the current understanding of the regulatory networks that underlie EMT in three physiological contexts: embryonic development, wound healing, and metastasis. We describe the existing experimental systems and manipulations used to better understand the molecular participants and factors that influence EMT and metastasis. We review the mathematical models of the regulatory networks involved in EMT, with a particular emphasis on the network motifs (such as coupled feedback loops) that can generate intermediate hybrid states between the epithelial and mesenchymal states. Ultimately, the understanding gained about these networks should be translated into methods to control phenotypic outcomes, especially in the context of cancer therapeutic strategies. We present emerging theories of how to drive the dynamics of a network toward a desired dynamical attractor (e.g. an epithelial cell state) and emerging synthetic biology technologies to monitor and control the state of cells.

Blocking Endogenous H2S Signaling Attenuated Radiation-Induced Long-Term Metastasis of Residual HepG2 Cells through Inhibition of EMT

Recurrence and metastasis of hepatocellular carcinoma (HCC) after radiotherapy are frequently observed in clinical practice. To date, the involved mechanism, endogenous hydrogen sulfide (H₂S), has not been well understood and warrants investigation. Here we demonstrated that both single-dose and fractionated irradiation enhanced metastasis of HCC cells both in vitro and in vivo at 20-60 days postirradiation. In particular, a gain in epithelial-mesenchymal transition (EMT) and mesenchymal features was observed. Further experiments revealed that endogenous H₂S signaling was constitutively activated after irradiation. Knockdown of cystathionine-γ-lyase (CSE) or cystathionine-β-synthase (CBS), two main H₂S-producing proteins, significantly diminished the increased expressions of EMT-related proteins induced by radiation through the p38MAPK pathway, leading to impaired invasion and metastasis of the residual HepG2 cells and their xenograft tumors. Moreover, blocking of the H₂S pathway increased the radiosensitivity of the HepG2 xenograft tumor. Collectively, our results strongly suggest that endogenous H₂S/CSE contributes to the long-term cell invasion and tumor metastasis induced by fractionated exposures and therefore, could become an attractive therapeutic target of HCC to eliminate radiotherapy-induced adverse effects.

EMT, stemness and tumor plasticity in aggressive variant neuroendocrine prostate cancers

Neuroendocrine/Aggressive Variant Prostate Cancers are lethal variants of the disease, with an aggressive clinical course and very short responses to conventional therapy. The age-adjusted incidence rate for this tumor sub-type has steadily increased over the past 20 years in the United States, with no reduction in the associated mortality rate. The molecular networks fueling its emergence and sustenance are still obscure; however, many factors have been associated with the onset and progression of neuroendocrine differentiation in clinically typical adenocarcinomas including loss of androgen-receptor expression and/or signaling, conventional therapy, and dysregulated cytokine function. "Tumor-plasticity" and the ability to dedifferentiate into alternate cell lineages are central to this process. Epithelial-to-mesenchymal (EMT) signaling pathways are major promoters of stem-cell properties in prostate tumor cells. In this review, we examine the contributions of EMT-induced cellular-plasticity and stem-cell signaling pathways to the progression of Neuroendocrine/Aggressive Variant Prostate Cancers in the light of potential therapeutic opportunities.

FOXP3 and miR-155 cooperate to control the invasive potential of human breast cancer cells by down regulating ZEB2 independently of ZEB1

Control of oncogenes, including ZEB1 and ZEB2, is a major checkpoint for preventing cancer, and loss of this control contributes to many cancers, including breast cancer. Thus tumour suppressors, such as FOXP3, which is mutated or lost in many cancer tissues, play an important role in maintaining normal tissue homeostasis. Here we show for the first time that ZEB2 is selectively down regulated by FOXP3 and also by the FOXP3 induced microRNA, miR-155. Interestingly, neither FOXP3 nor miR-155 directly altered the expression of ZEB1. In breast cancer cells repression of ZEB2, independently of ZEB1, resulted in reduced expression of a mesenchymal marker, Vimentin and reduced invasion. However, there was no de-repression of E-cadherin and migration was enhanced. Small interfering RNAs targeting ZEB2 suggest that this was a direct effect of ZEB2 and not FOXP3/miR-155. In normal human mammary epithelial cells, depletion of endogenous FOXP3 resulted in de-repression of ZEB2, accompanied by upregulated expression of vimentin, increased E-cadherin expression and cell morphological changes. We suggest that FOXP3 may help maintain normal breast epithelial characteristics through regulation of ZEB2, and loss of FOXP3 in breast cancer cells results in deregulation of ZEB2.

A Forkhead Box Protein C2 Inhibitor: Targeting Epithelial-Mesenchymal Transition and Cancer Metastasis

The epithelial-mesenchymal transition (EMT) has been suggested as a new target for therapeutic intervention of metastatic cancer. Forkhead box protein C2 (FOXC2) is known to be necessary for initiating and maintaining EMT, and therefore bestows on cancer cells metastatic and cancer stem cell (CSC)-like phenotypes, allowing cells to acquire higher motility, invasiveness, self-renewal, and therapy resistance. Here, we describe the first inhibitor of FOXC2, MC-1-F2. MC-1-F2 was able to induce cadherin switching and reverse EMT through the degradation of FOXC2 and blocking of its nuclear localization. In addition, MC-1-F2 was very effective in inhibiting cancer cell migration and invasion. As the first small-molecule inhibitor of FOXC2 and the first compound targeting EMT-associated transcription factor, MC-1-F2 will pave the way for a new anticancer therapeutic agent targeting metastatic cancer and help to elucidate the network of EMT signaling pathways.

A functional genomic screen in vivo identifies CEACAM5 as a clinically relevant driver of breast cancer metastasis

Tumor cells disseminate early in tumor development making metastasis-prevention strategies difficult. Identifying proteins that promote the outgrowth of disseminated tumor cells may provide opportunities for novel therapeutic strategies. Despite multiple studies demonstrating that the mesenchymal-to-epithelial transition (MET) is critical for metastatic colonization, key regulators that initiate this transition remain unknown. We serially passaged lung metastases from a primary triple negative breast cancer xenograft to the mammary fat pads of recipient mice to enrich for gene expression changes that drive metastasis. An unbiased transcriptomic signature of potential metastatic drivers was generated, and a high throughput gain-of-function screen was performed in vivo to validate candidates. Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) was identified as a metastatic driver. CEACAM5 overproduction enriched for an epithelial gene expression pattern and facilitated tumor outgrowth at metastatic sites. Tissues from patients with metastatic breast cancer confirmed elevated levels of CEACAM5 in lung metastases relative to breast tumors, and an inverse correlation between CEACAM5 and the mesenchymal marker vimentin was demonstrated. Thus, CEACAM5 facilitates tumor outgrowth at metastatic sites by promoting MET, warranting its investigation as a therapeutic target and biomarker of aggressiveness in breast cancer.

A screen for drivers of metastasis has revealed a key protein involved in the spread of breast cancer into lung tissues. A US research team led by Helen Piwnica-Worms from the University of Texas MD Anderson Cancer Center in Houston enriched cells for genes involved in metastasis by engrafting mice with breast tumor biopsies taken from women with metastatic triple negative breast cancer and then metastases of these mice to mammary fat pads of recipient mice. The researchers pinpointed the gene encoding CEACAM5—a protein known to play a role in cell invasion and spread—as a key promoter of the cellular transition associated with metastasis. Tissues samples from patients confirmed that CEACAM5 levels were elevated in metastatic lung tumors relative to primary breast tumors. The protein provides a potential therapeutic target for drug development and candidate biomarker for patient stratification.

Emerging roles and mechanisms of FOXC2 in cancer

Forkhead box protein C2 (FOXC2), a transcription factor of the forkhead/winged-helix family, is required for embryonic and prenatal development. FOXC2 acts as a crucial modulator during both angiogenesis and lymphangiogenesis via multiple angiogenic and lymphangiogenic pathways, respectively. Although recent studies have shed light on the emerging role of FOXC2 in cancer, very little is known about the precise underlying mechanisms. The purpose of this review is to summarize the current understanding of FOXC2 and provide potential mechanistic explanations of the relationship between FOXC2 and cancer, as well as discuss the prospect for future research in the promising prognostic value of FOXC2 in cancer.

Distinguishing mechanisms underlying EMT tristability

Background

The Epithelial-Mesenchymal Transition (EMT) endows epithelial-looking cells with enhanced migratory ability during embryonic development and tissue repair. EMT can also be co-opted by cancer cells to acquire metastatic potential and drug-resistance. Recent research has argued that epithelial (E) cells can undergo either a partial EMT to attain a hybrid epithelial/mesenchymal (E/M) phenotype that typically displays collective migration, or a complete EMT to adopt a mesenchymal (M) phenotype that shows individual migration. The core EMT regulatory network - miR-34/SNAIL/miR-200/ZEB1 - has been identified by various studies, but how this network regulates the transitions among the E, E/M, and M phenotypes remains controversial. Two major mathematical models - ternary chimera switch (TCS) and cascading bistable switches (CBS) - that both focus on the miR-34/SNAIL/miR-200/ZEB1 network, have been proposed to elucidate the EMT dynamics, but a detailed analysis of how well either or both of these two models can capture recent experimental observations about EMT dynamics remains to be done.

Results

Here, via an integrated experimental and theoretical approach, we first show that both these two models can be used to understand the two-step transition of EMT - E→E/M→M, the different responses of SNAIL and ZEB1 to exogenous TGF-β and the irreversibility of complete EMT. Next, we present new experimental results that tend to discriminate between these two models. We show that ZEB1 is present at intermediate levels in the hybrid E/M H1975 cells, and that in HMLE cells, overexpression of SNAIL is not sufficient to initiate EMT in the absence of ZEB1 and FOXC2.

Conclusions

These experimental results argue in favor of the TCS model proposing that miR-200/ZEB1 behaves as a three-way decision-making switch enabling transitions among the E, hybrid E/M and M phenotypes.

Decrypting the PAK4 transcriptome profile in mammary tumor forming cells using Next Generation Sequencing

The p-21 Activated Kinase 4 (PAK4) protein kinase is implicated in many cancers, including breast cancer. Overexpression of PAK4 is sufficient to cause mouse mammary epithelial cells (iMMECs) to become tumorigenic. To gain insight into the long-term gene expression changes that occur downstream to PAK4, we performed Next Generation Sequencing of RNA collected from PAK4 overexpressing iMMECs and wild-type iMMECs. We identified a list of genes whose expression levels were altered in response to PAK4 overexpression in iMMECs. Some of these genes, including FoxC2 and ParvB, are consistent with a role for PAK4 in cancer. In addition, PAK4 regulates many genes that are frequently associated with the inflammatory response, raising the possibility that there is a connection between PAK4, inflammation, and the tumor microenvironment. This study delineates the PAK4 transcriptome profile in transformed mammary cells and can provide translational utility in other types of cancers as well.

Role and importance of the expression of transcription factor FOXC2 in cervical cancer

The aim of the present study was to investigate the relationship between the expression of transcription factor forkhead box C2 (FOXC2) and the clinical features of cervical cancer. A total of 66 patients with cervical cancer, 42 patients with cervical intraepithelial neoplasia (CIN) and 25 patients with cervical inflammation were enrolled. The positive expression rates and expression levels of mRNA of FOXC2, E-cadherin, N-cadherin, vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 (SDF-1), Notch protein and lymphatic vessel endothelial hyaluronan receptor-1 (LYVE-1) in cervical tissues were detected using immunohistochemistry and RT-PCR. The positive expression rates and expression levels of mRNA of FOXC2, N-cadherin, VEGF, SDF-1, Notch and LYVE-1 in cervical cancer were significantly higher than those in CIN, and those in the inflammatory tissues were the lowest, while the positive expression rate of E-cadherin in cervical cancer was lower than that in CIN, and that in the inflammatory tissues was the highest (P<0.05). The positive expression rates of FOXC2, N-cadherin, VEGF, SDF-1, Notch and LYVE-1 in patients with cervical cancer [human papillomavirus (HPV) positive, squamous cell carcinoma, Stages III–IV, maximal diameter ≥3.8 cm and low differentiation] were increased, and the positive expression rate of E-cadherin was decreased (P<0.05). Correlation analysis revealed that FOXC2 was positively correlated with the positive expression rates of N-cadherin, VEGF, SDF-1, Notch and LYVE-1, and negatively correlated with E-cadherin (P<0.05). In conclusion, the high expression of FOXC2 is correlated with the HPV infection, pathological pattern, clinical stage, tumor diameter and differentiation grade of cervical cancer, which may be involved in the epithelial-mesenchymal transition, vascular and matrix formation, Notch signaling pathway and lymphangiogenesis.

MicroRNA Let-7g Directly Targets Forkhead Box C2 (FOXC2) to Modulate Bone Metastasis in Breast Cancer

Aberrantly expressed microRNAs have been implicated in lots of cancers. Reduced amounts of let-7g have been found in breast cancer tissues. The function of let-7g in bone metastasis of breast cancer remains poorly understood. This study is to explore the significance of let-7g and its novel target gene in bone metastasis of breast cancer.

The expression of let-7g or forkhead box C2 (FOXC2) was measured in human clinical breast cancer tissues with bone metastasis by using quantitative real-time Polymerase Chain Reaction (qRT-PCR). After transfection with let-7g or anti-let-7g in breast cancer cell linesMDA-MB-231or SK-BR3, qRT-PCR and Western blot were done to test the levels of let-7g and FOXC2. The effect of anti-let-7g and/ or FOXC2 RNA interference (RNAi) on cell migration in breast cancer cells was evaluated by using wound healing assay.

Clinically, qRT-PCR showed that FOXC2 levels were higher in breast cancer tissues with bone metastasis than those in their noncancerous counterparts. Let-7g was showed to be negatively correlated with FOXC2 in human breast cancer samples with bone metastasis. We found that enforced expression of let-7g reduced levels of FOXC2 protein by using Western blot in MDA-MB-231 cells. Conversely, anti-let-7g enhanced levels of FOXC2 in SK-BR3 cells. In terms of function, anti-let-7g accelerated migration of SK-BR3 cells. Interestingly, FOXC2 RNAi abrogated anti-let-7g-mediated migration in breast cancer cells. Thus, we conclude that let-7g suppresses cell migration through targeting FOXC2 in breast cancer. Our finding provides a new perspective for understanding the mechanism of bone metastasis in breast cancer.

Cancer metastasis through the prism of epithelial-to-mesenchymal transition in circulating tumor cells

Metastasis of epithelial cancer cells to distant sites is a particularly critical stage of cancer progression that typically marks the incurability of the disease. It is governed by a complex series of events including invasion and intravasation of tumor cells into the stroma and blood, respectively. Epithelial-to-mesenchymal transition (EMT), a phenotypic change marked by the loss of epithelial characteristics and the acquisition of invasive mesenchymal properties, is implicated in the dissemination of tumor cells. Circulating tumor cells (CTCs), the precursors of metastasis, can be used to interrogate the contribution of EMT in metastasis and therapeutic responses. The analysis of these CTCs and in particular the presence of inter- and intrapatient heterogeneity for markers of EMT has provided new insights into the metastatic process. This review will focus on epithelial-mesenchymal plasticity in CTCs and its potential clinical implications.

Expression of FOXC2, PinX1, Ki-67 and Cyclin D1 in cutaneous cell carcinoma

We investigated the expression of FOXC2, PinX1, Ki-67 and Cyclin D1 in cutaneous cell carcinoma. We collected 30 cutaneous squamous cell carcinoma (SCC), 30 cutaneous basal cell carcinoma (BCC) and 30 normal skin tissues. The protein expression and gene expression of FOXC2, endogenous telomerase-inhibiting gene PinX1, Ki-67 and Cyclin D1 was measured by immunohistochemistry (IHC) and semi-quantitative reverse transcription polymerase chain reaction (RT-PCR), respectively. In SCC and BCC tissues, the positive rate of protein expression and mRNA level of PinX1 were both significantly lower than those in normal tissues. However, the positive rate of protein expression and mRNA level of FOXC2, Ki-67 and Cyclin D1 were significantly higher than those in normal tissues (p<0.05). There was no significant difference between SCC and BCC (p>0.05). In conclusion, FOXC2 may participate in the carcinogenesis process of SCC and BCC. It may also correlate with the expression PinX, Ki-67 and Cyclin D1. However, FOXC2 alone cannot be used as a diagnostic indicator of SCC.