ZEB1 Promotes invasiveness of colorectal carcinoma cells through the opposing regulation of uPA and PAI-1

Doxorubicin-loaded zymosan nanoparticles: Synergistic cytotoxicity and modulation of apoptosis and Wnt/β-catenin signaling pathway in C26 colorectal cancer cells

Zymosan is a β-glucan isolated from Saccharomyces cerevisiae that could be employed for drug delivery. We synthesized zymosan nanoparticles and measured their structural and morphological properties using XRD, UV-Vis spectroscopy, TEM and AFM. The loading of doxorubicin (DOX) onto the nanoparticles was confirmed by FT-IR, and the DOX release was shown to be pH-dependent. The effect of these agents on C26 cell viability was evaluated by MTT tests and the expression of genes connected with the Wnt/β-catenin pathway and apoptosis were analyzed by RT-qPCR and Western blotting. Treatments were able to suppress the proliferation of C26 cells, and the zymosan nanocarriers loaded with DOX enhanced the anti-proliferative effect of DOX in a synergistic manner. Zymosan nanoparticles were able to suppress the expression of cyclin D1, VEGF, ZEB1, and Twist mRNAs. Treatment groups upregulated the expression of caspase-8, while reducing the Bax/Bcl-2 ratio, thus promoting apoptosis. In conclusion, zymosan nanoparticles as DOX nanocarriers could provide a more targeted drug delivery through pH-responsiveness, and showed synergistic cytotoxicity by modifying Wnt/β-catenin signaling and apoptosis.

CD73 mitigates ZEB1 expression in papillary thyroid carcinoma

BACKGROUND

ZEB1, a core transcription factor involved in epithelial-mesenchymal transition (EMT), is associated with aggressive cancer cell behavior, treatment resistance, and poor prognosis across various tumor types. Similarly, the expression and activity of CD73, an ectonucleotidase implicated in adenosine generation, is an important marker of tumor malignancy. Growing evidence suggests that EMT and the adenosinergic pathway are intricately linked and play a pivotal role in cancer development. Therefore, this study focuses on exploring the correlations between CD73 and ZEB1, considering their impact on tumor progression.

METHODS

We employed CRISPR/Cas9 technology to silence CD73 expression in cell lines derived from papillary thyroid carcinoma. These same cells underwent lentiviral transduction of a reporter of ZEB1 non-coding RNA regulation. We conducted studies on cell migration using scratch assays and analyses of cellular speed and polarity. Additionally, we examined ZEB1 reporter expression through flow cytometry and immunocytochemistry, complemented by Western blot analysis for protein quantification. For further insights, we applied gene signatures representing different EMT states in an RNA-seq expression analysis of papillary thyroid carcinoma samples from The Cancer Genome Atlas.

RESULTS

Silencing CD73 expression led to a reduction in ZEB1 non-coding RNA regulation reporter expression in a papillary thyroid carcinoma-derived cell line. Additionally, it also mitigated ZEB1 protein expression. Moreover, the expression of CD73 and ZEB1 was correlated with alterations in cell morphology characteristics crucial for cell migration, promoting an increase in cell polarity index and cell migration speed. RNA-seq analysis revealed higher expression of NT5E (CD73) in samples with BRAF mutations, accompanied by a prevalence of partial-EMT/hybrid state signature expression.

CONCLUSIONS

Collectively, our findings suggest an association between CD73 expression and/or activity and the post-transcriptional regulation of ZEB1 by non-coding RNA, indicating a reduction in its absence. Further investigations are warranted to elucidate the relationship between CD73 and ZEB1, with the potential for targeting them as therapeutic alternatives for cancer treatment in the near future.

The EMT factor ZEB1 paradoxically inhibits EMT in BRAF-mutant carcinomas

Despite being in the same pathway, mutations of KRAS and BRAF in colorectal carcinomas (CRCs) determine distinct progression courses. ZEB1 induces an epithelial-to-mesenchymal transition (EMT) and is associated with worse progression in most carcinomas. Using samples from patients with CRC, mouse models of KrasG12D and BrafV600E CRC, and a Zeb1-deficient mouse, we show that ZEB1 had opposite functions in KRAS- and BRAF-mutant CRCs. In KrasG12D CRCs, ZEB1 was correlated with a worse prognosis and a higher number of larger and undifferentiated (mesenchymal or EMT-like) tumors. Surprisingly, in BrafV600E CRC, ZEB1 was associated with better prognosis; fewer, smaller, and more differentiated (reduced EMT) primary tumors; and fewer metastases. ZEB1 was positively correlated in KRAS-mutant CRC cells and negatively in BRAF-mutant CRC cells with gene signatures for EMT, cell proliferation and survival, and ERK signaling. On a mechanistic level, ZEB1 knockdown in KRAS-mutant CRC cells increased apoptosis and reduced clonogenicity and anchorage-independent growth; the reverse occurred in BRAFV600E CRC cells. ZEB1 is associated with better prognosis and reduced EMT signature in patients harboring BRAF CRCs. These data suggest that ZEB1 can function as a tumor suppressor in BRAF-mutant CRCs, highlighting the importance of considering the KRAS/BRAF mutational background of CRCs in therapeutic strategies targeting ZEB1/EMT.

The Roles of Zinc Finger Proteins in Colorectal Cancer

Despite colorectal cancer remaining a leading worldwide cause of cancer-related death, there remains a paucity of effective treatments for advanced disease. The molecular mechanisms underlying the development of colorectal cancer include altered cell signaling and cell cycle regulation that may result from epigenetic modifications of gene expression and function. Acting as important transcriptional regulators of normal biological processes, zinc finger proteins also play key roles in regulating the cellular mechanisms underlying colorectal neoplasia. These actions impact cell differentiation and proliferation, epithelial-mesenchymal transition, apoptosis, homeostasis, senescence, and maintenance of stemness. With the goal of highlighting promising points of therapeutic intervention, we review the oncogenic and tumor suppressor roles of zinc finger proteins with respect to colorectal cancer tumorigenesis and progression.

Role of Interleukins in Inflammation-Mediated Tumor Immune Microenvironment Modulation in Colorectal Cancer Pathogenesis

INTRODUCTION

Tumor cells invade and spread through a procedure termed as epithelial-to-mesenchymal cell transition (EMT). EMT is triggered by any alterations in the genes that encode the extracellular matrix (ECM) proteins, the enzymes that break down the ECM, and the activation of the genes that causes the epithelial cell to change into a mesenchymal type. The transcription factors NF-κB, Smads, STAT3, Snail, Zeb, and Twist are activated by inflammatory cytokines, for instance, Tumor Necrosis Factor, Tumor Growth Factors, Interleukin-1, Interleukin-8, and Interleukin-6, which promotes EMT.

MATERIALS

The current piece of work has been reviewed from the literature works published in last 10 years on the role interleukins in inflammation-mediated tumor immune microenvironment modulation in colorectal cancer pathogenesis utilizing the databases like Google Scholar, PubMed, Science Direct.

RESULTS

Recent studies have demonstrated that pathological situations, such as epithelial malignancies, exhibit EMT characteristics, such as the downregulation of epithelial markers and the overexpression of mesenchymal markers. Several growing evidence have also proved its existence in the human colon during the carcinogenesis of colorectal cancer. Most often, persistent inflammation is thought to be one factor contributing to the initiation of human cancers, such as colorectal cancer (CRC). Therefore, according to epidemiologic and clinical research, people with ulcerative colitis and Crohn's disease have a greater probability of developing CRC.

CONCLUSION

A substantial amount of data points to the involvement of the NF-κB system, SMAD/STAT3 signaling cascade, microRNAs, and the Ras-mitogen-activated protein kinase/Snail/Slug in the epithelial-to-mesenchymal transition-mediated development of colorectal malignancies. As a result, EMT is reported to play an active task in the pathogenesis of colorectal cancer, and therapeutic interventions targeting the inflammation-mediated EMT might serve as a novel strategy for treating CRC. The illustration depicts the relationship between interleukins and their receptors as a driver of CRC development and the potential therapeutic targets.

Good or bad: Paradox of plasminogen activator inhibitor 1 (PAI-1) in digestive system tumors

The fibrinolytic system is involved in many physiological functions, among which the important members can interact with each other, either synergistically or antagonistically to participate in the pathogenesis of many diseases. Plasminogen activator inhibitor 1 (PAI-1) acts as a crucial element of the fibrinolytic system and functions in an anti-fibrinolytic manner in the normal coagulation process. It inhibits plasminogen activator, and affects the relationship between cells and extracellular matrix. PAI-1 not only involved in blood diseases, inflammation, obesity and metabolic syndrome but also in tumor pathology. Especially PAI-1 plays a different role in different digestive tumors as an oncogene or cancer suppressor, even a dual role for the same cancer. We term this phenomenon "PAI-1 paradox". PAI-1 is acknowledged to have both uPA-dependent and -independent effects, and its different actions can result in both beneficial and adverse consequences. Therefore, this review will elaborate on PAI-1 structure, the dual value of PAI-1 in different digestive system tumors, gene polymorphisms, the uPA-dependent and -independent mechanisms of regulatory networks, and the drugs targeted by PAI-1 to deepen the comprehensive understanding of PAI-1 in digestive system tumors.

Association of SNPs in the PAI1 Gene with Disease Recurrence and Clinical Outcome in Bladder Cancer

PURPOSE

Bladder cancer (BCa) is one of the most common cancer types worldwide and is characterized by a high rate of recurrence. In previous studies, we and others have described the functional influence of plasminogen activator inhibitor-1 (PAI1) in bladder cancer development. While polymorphisms in PAI1 have been associated with increased risk and worsened prognosis in some cancers, the mutational status of PAI1 in human bladder tumors has not been well defined.

METHODS

In this study, we evaluated the mutational status of PAI1 in a series of independent cohorts, comprised of a total of 660 subjects.

RESULTS

Sequencing analyses identified two clinically relevant 3' untranslated region (UTR) single nucleotide polymorphisms (SNPs) in PAI1 (rs7242; rs1050813). Somatic SNP rs7242 was present in human BCa cohorts (overall incidence of 72%; 62% in Caucasians and 72% in Asians). In contrast, the overall incidence of germline SNP rs1050813 was 18% (39% in Caucasians and 6% in Asians). Furthermore, Caucasian patients with at least one of the described SNPs had worse recurrence-free survival and overall survival (p = 0.03 and p = 0.03, respectively). In vitro functional studies demonstrated that SNP rs7242 increased the anti-apoptotic effect of PAI1, and SNP rs1050813 was related to a loss of contact inhibition associated with cellular proliferation when compared to wild type.

CONCLUSION

Further investigation of the prevalence and potential downstream influence of these SNPs in bladder cancer is warranted.

Tumour-associated macrophages enhance breast cancer malignancy via inducing ZEB1-mediated DNMT1 transcriptional activation

Background

DNMT1 has been shown to be highly expressed in a variety of cancers, including breast cancer. However, the mechanism is not very clear. Therefore, we aim to reveal the mechanism of DNMT1 highly express in breast cancer. And we also want to explore the role of DNMT1 in tumour microenvironment promoting breast cancer progression.

Results

In this study, we demonstrate that DNMT1 is overexpressed in breast cancer and that DNMT1 promotes breast cancer tumorigenesis and metastasis. We discovered that ZEB1 activates DNMT1 expression in breast cancer cells by recruiting P300 binding to the DNMT1 promoter and increasing its acetylation. Moreover, we revealed that tumour-associated macrophages (TAMs) increase DNMT1 expression in breast cancer cells via the IL-6-pSTAT3-ZEB1-DNMT1 axis in the tumour microenvironment. DNMT1 is required for TAM-mediated breast cancer cell migration. In addition, we confirmed that there were positive correlations among CD163 (TAM marker) expression, ZEB1 expression and DNMT1 expression in breast cancer patient tissues.

Conclusions

Our study indicates that DNMT1 is necessary for TAM-mediated breast cancer metastasis. Decitabine (DAC), as a specific DNA methylation inhibitor and FDA-approved drug, is a bona fide drug for breast cancer treatment.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13578-022-00913-4.

Wnt signaling in colorectal cancer: pathogenic role and therapeutic target

Background

The Wnt signaling pathway is a complex network of protein interactions that functions most commonly in embryonic development and cancer, but is also involved in normal physiological processes in adults. The canonical Wnt signaling pathway regulates cell pluripotency and determines the differentiation fate of cells during development. The canonical Wnt signaling pathway (also known as the Wnt/β-catenin signaling pathway) is a recognized driver of colon cancer and one of the most representative signaling pathways. As a functional effector molecule of Wnt signaling, the modification and degradation of β-catenin are key events in the Wnt signaling pathway and the development and progression of colon cancer. Therefore, the Wnt signaling pathway plays an important role in the pathogenesis of diseases, especially the pathogenesis of colorectal cancer (CRC).

Objective

Inhibit the Wnt signaling pathway to explore the therapeutic targets of colorectal cancer.

Methods

Based on studying the Wnt pathway, master the biochemical processes related to the Wnt pathway, and analyze the relevant targets when drugs or inhibitors act on the Wnt pathway, to clarify the medication ideas of drugs or inhibitors for the treatment of diseases, especially colorectal cancer.

Results

Wnt signaling pathways include: Wnt/β-catenin or canonical Wnt signaling pathway, planar cell polarity (Wnt-PCP) pathway and Wnt-Ca²⁺ signaling pathway. The Wnt signaling pathway is closely related to cancer cell proliferation, stemness, apoptosis, autophagy, metabolism, inflammation and immunization, microenvironment, resistance, ion channel, heterogeneity, EMT/migration/invasion/metastasis. Drugs/phytochemicals and molecular preparations for the Wnt pathway of CRC treatment have now been developed. Wnt inhibitors are also commonly used clinically for the treatment of CRC.

Conclusion

The development of drugs/phytochemicals and molecular inhibitors targeting the Wnt pathway can effectively treat colorectal cancer clinically.

Cinnamaldehyde decreases the invasion and u-PA expression of osteosarcoma by down-regulating the FAK signalling pathway

Cancer metastasis is the major cause of the high mortality risk of patients with osteosarcoma. Cinnamaldehyde has been shown to exhibit multiple tumour-suppressing activities, but its role in human osteosarcoma is not yet completely defined. In this study, the antimetastatic effect of cinnamaldehyde on highly metastatic human osteosarcoma cells was observed in vitro and in vivo using Saos-2 and 143B cells. Cinnamaldehyde reduced the activity and protein level of urokinase-type plasminogen activator (u-PA) and suppressed the invasion ability of osteosarcoma cells by inhibiting the phosphorylation of focal adhesion kinase. In addition, cinnamaldehyde reduced cell movement, cell-matrix adhesion, and the expression of the mesenchymal markers of epithelial-to-mesenchymal transition, namely, fibronectin and N-cadherin. Importantly, the oral administration of cinnamaldehyde remarkably suppressed the pulmonary metastasis of osteosarcoma in mice. Results indicated that cinnamaldehyde has therapeutic potential for inhibiting osteosarcoma metastasis.

Zinc finger protein 280C contributes to colorectal tumorigenesis by maintaining epigenetic repression at H3K27me3-marked loci

This study uncovered the role of ZNF280C, a known DNA damage response protein, as a tumorigenic transcription regulator that contributes to colorectal tumorigenesis and metastasis through maintaining an epigenetic repression program at key cancer gene loci. These findings identified a contributor with potential prognostic value to colorectal pathogenesis and provide mechanistic insight to the essential function of transcription factor in fine-tuning the activity of chromatin regulators for proper transcription control.

Dysregulated epigenetic and transcriptional programming due to abnormalities of transcription factors (TFs) contributes to and sustains the oncogenicity of cancer cells. Here, we unveiled the role of zinc finger protein 280C (ZNF280C), a known DNA damage response protein, as a tumorigenic TF in colorectal cancer (CRC), required for colitis-associated carcinogenesis and Apc deficiency–driven intestinal tumorigenesis in mice. Consistently, ZNF280C silencing in human CRC cells inhibited proliferation, clonogenicity, migration, xenograft growth, and liver metastasis. As a C2H2 (Cys2-His2) zinc finger-containing TF, ZNF280C occupied genomic intervals with both transcriptionally active and repressive states and coincided with CCCTC-binding factor (CTCF) and cohesin binding. Notably, ZNF280C was crucial for the repression program of trimethylation of histone H3 at lysine 27 (H3K27me3)-marked genes and the maintenance of both focal and broad H3K27me3 levels. Mechanistically, ZNF280C counteracted CTCF/cohesin activities and condensed the chromatin environment at the cis elements of certain tumor suppressor genes marked by H3K27me3, at least partially through recruiting the epigenetic repressor structural maintenance of chromosomes flexible hinge domain-containing 1 (SMCHD1). In clinical relevance, ZNF280C was highly expressed in primary CRCs and distant metastases, and a higher ZNF280C level independently predicted worse prognosis of CRC patients. Thus, our study uncovered a contributor with good prognostic value to CRC pathogenesis and also elucidated the essence of DNA-binding TFs in orchestrating the epigenetic programming of gene regulation.

The role of epithelial-mesenchymal transition-regulating transcription factors in anti-cancer drug resistance

The complex orchestration of gene expression that mediates the transition of epithelial cells into mesenchymal cells is implicated in cancer development and metastasis. As the primary regulator of the process, epithelial-mesenchymal transition-regulating transcription factors (EMT-TFs) play key roles in metastasis. They are also highlighted in recent preclinical studies on resistance to cancer therapy. This review describes the role of three main EMT-TFs, including Snail, Twist1, and zinc-finger E homeobox-binding 1 (ZEB1), relating to drug resistance and current possible approaches for future challenges targeting EMT-TFs.

LncRNA SLC7A11-AS1 Contributes to Lung Cancer Progression Through Facilitating TRAIP Expression by Inhibiting miR-4775

Purpose

Long non-coding RNAs (lncRNAs) are important regulators of lung cancer. This article introduced a novel lncRNA, SLC7A11-AS1, whose effects on lung cancer development have been explored.

Methods

Lung cancer tissues and normal tissues of 47 patients were collected. Bronchial epithelial cell line (BEAS-2B) and lung cancer cell lines (H520, H596, A549 and H1299) were cultured. H1299 and A549 cells were transfected with siSLC7A11-AS1 or siNC. The proliferation, migration and invasion of H1299 and A549 cells were detected by CCK-8 assay and Transwell experiment. Caspase-3 activity in H1299 and A549 cells was researched using caspase-3 activity detection kit. Dual-luciferase reporter gene assay and RNA pull-down assay were performed to explore the relationship between SLC7A11-AS1 and miR-4775. SLC7A11-AS1, miR-4775 and TRAIP mRNA expressions in tissues/cells were detected by qRT-PCR.

Results

The up-regulated SLC7A11-AS1 in lung cancer patients was associated with metastasis and advanced tumor stage (P < 0.05). SLC7A11-AS1 was significantly up-regulated in lung cancer cells (P < 0.05). Silencing of SLC7A11-AS1 prominently inhibited H1299 and A549 cells proliferation, migration and invasion in vitro (P < 0.05). SLC7A11-AS1 acted as a sponge to inhibit miR-4775 expression in H1299 and A549 cells. Meanwhile, TRAIP expression in H1299 and A549 cells was directly and negatively regulated by miR-4775. Inhibition of miR-4775 or overexpression of TRAIP in H1299 and A549 cells remarkably reversed the reduced proliferation, migration and invasion induced by SLC7A11-AS1 silencing (P < 0.05).

Conclusion

SLC7A11-AS1 promoted lung cancer development by enhancing TRAIP expression via suppressing miR-4775.

Downregulation of serum exosomal miR-150-5p is associated with poor prognosis in patients with colorectal cancer

Growing evidence have revealed the serum exosomal miRNAs emerged as biomarkers for various cancer types, including colorectal cancer (CRC). Here, we sought to explore the potential clinical significance of serum exosomal miR-150-5p in CRC. A total of 133 CRC patients and 60 healthy volunteers as control group were recruited in this study. Exosomes were isolated from the serum of all the participants. The total RNA was isolated from the exosomes and the serum exosomal miR-150-5p levels were measured by quantitative reverse transcription-polymerase chain reaction. The findings showed that the serum exosomal miR-150-5p levels were significantly reduced in CRC cases compared with those in the control group. Serum exosomal miR-150-5p levels in post-operative blood samples were greatly upregulated one month after surgical treatment. In addition, decreased serum exosomal miR-150-5p expression was closely correlated with poorly differentiation, positive lymph node metastasis and advanced TNM stage. Moreover, receiver operating characteristic (ROC) curve analysis showed serum exosomal miR-150-5p level had good performance to identify CRC cases from healthy volunteers, and a combination of serum exosomal miR-150-5p and carcinoembryonic antigen (CEA) could improve the diagnostic accuracy with an increased the area under the ROC curve (AUC) value. Furthermore, the survival time of patients with higher serum exosomal miR-150-5p expression was significantly longer than those with lower expression. Serum exosomal miR-150-5p was confirmed as an independent prognostic indicator in CRC. Mechanistically, ZEB1 was identified as a direct downstream target of miR-150-5p. Collectively, serum exosomal miR-150-5p might be a novel noninvasive biomarker for CRC diagnosis and prognosis.

ZEB1 promotes inflammation and progression towards inflammation-driven carcinoma through repression of the DNA repair glycosylase MPG in epithelial cells

OBJECTIVE

Chronic inflammation is a risk factor in colorectal cancer (CRC) and reactive oxygen species (ROS) released by the inflamed stroma elicit DNA damage in epithelial cells. We sought to identify new drivers of ulcerative colitis (UC) and inflammatory CRC.

DESIGN

The study uses samples from patients with UC, mouse models of colitis and CRC and mice deficient for the epithelial-to-mesenchymal transition factor ZEB1 and the DNA repair glycosylase N-methyl-purine glycosylase (MPG). Samples were analysed by immunostaining, qRT-PCR, chromatin immunoprecipitation assays, microbiota next-generation sequencing and ROS determination.

RESULTS

ZEB1 was induced in the colonic epithelium of UC and of mouse models of colitis. Compared with wild-type counterparts, Zeb1-deficient mice were partially protected from experimental colitis and, in a model of inflammatory CRC, they developed fewer tumours and exhibited lower levels of DNA damage (8-oxo-dG) and higher expression of MPG. Knockdown of ZEB1 in CRC cells inhibited 8-oxo-dG induction by oxidative stress (H₂O₂) and inflammatory cytokines (interleukin (IL)1β). ZEB1 bound directly to the MPG promoter whose expression inhibited. This molecular mechanism was validated at the genetic level and the crossing of Zeb1-deficient and Mpg-deficient mice reverted the reduced inflammation and tumourigenesis in the former. ZEB1 expression in CRC cells induced ROS and IL1β production by macrophages that, in turn, lowered MPG in CRC cells thus amplifying a positive loop between both cells to promote DNA damage and inhibit DNA repair.

CONCLUSIONS

ZEB1 promotes colitis and inflammatory CRC through the inhibition of MPG in epithelial cells, thus offering new therapeutic strategies to modulate inflammation and inflammatory cancer.

Induction of Urokinase Activity by Retinoic Acid in Two Cell Lines of Neuronal Origin

Retinoic acid is one of the most well-known agents able to induce differentiation in several types of tumours. Unfortunately, most of the tumours are refractive to the differentiation cues. The aim of this investigation was to analyse the effects of prolonged treatment with retinoic acid on two cell lines of neural origin refractive to differentiation. Cells were also treated with retinoic acid in combination with a poly(ADP-ribosyl) polymerase (PARP) inhibitor because PARP1 is a known chromatin modulator and can influence the process of differentiation. The main methods comprised tumour cell line culturing and treatment; analysis of RNA and protein expression after cell treatment; as well as analysis of urokinase activity, migration, and proliferation. Both cell lines continued to proliferate under the prolonged treatment and showed increase in urokinase plasminogen activator activity. Analysis of gene expression and cell phenotype revealed different mechanisms, which only in neuroblastoma H4 cells could indicate the process of epithelial-mesenchymal transition. The data collected indicate that the activity of the urokinase plasminogen activator, although belonging to an extracellular protease, does not necessary lead to epithelial-mesenchymal reprogramming and increase in cell migration but can have different outcomes depending on the intracellular milieu.

TGF-β-mediated regulation of plasminogen activators is human telomerase reverse transcriptase dependent in cancer cells

Telomerase is a specialized reverse transcriptase/terminal transferase enzyme that adds telomeric repeat sequences at the extreme end of a newly replicated chromosome. Apart from telomere lengthening, telomerase has many extracurricular activities. Telomerase is known to regulate the expression of many genes and helps in cancer progression and epithelial-to-mesenchymal transitions (EMTs). We have previously reported that human telomerase reverse transcriptase (hTERT) regulates the expression of plasminogen activator such as urokinase-type plasminogen activator (uPA) in cancer cells following a genome-wide transcriptomic study. Here, we present data substantiating these results in terms of real-time assays, western blots, and immunofluorescence. Another aim of this study is to find out the possible mechanism by which hTERT regulates the expression of plasminogen activators. We have used some molecular biology techniques such as quantitative real-time polymerase chain reaction, western blotting, and immunofluorescence and some assays such as wound healing assay and colony formation assay to solve this question. In this study, we show a positive association between hTERT and uPA. We also demonstrate that hTERT enhances uPA expression concomitant with EMT. Knocking down of hTERT reduces uPA expression as well as reverses EMT in cancer cells. We have also found that uPA is a transforming growth factor beta (TGF-β)-induced protein. Our observations establish that TGF-β-induced uPA expression is hTERT dependent.

Whole transcriptome analysis reveals correlation of long noncoding RNA ZEB1-AS1 with invasive profile in melanoma

Melanoma is the deadliest form of skin cancer, and little is known about the impact of deregulated expression of long noncoding RNAs (lncRNAs) in the progression of this cancer. In this study, we explored RNA-Seq data to search for lncRNAs associated with melanoma progression. We found distinct lncRNA gene expression patterns across melanocytes, primary and metastatic melanoma cells. Also, we observed upregulation of the lncRNA ZEB1-AS1 (ZEB1 antisense RNA 1) in melanoma cell lines. Data analysis from The Cancer Genome Atlas (TCGA) confirmed higher ZEB1-AS1 expression in metastatic melanoma and its association with hotspot mutations in BRAF (B-Raf proto-oncogene, serine/threonine kinase) gene and RAS family genes. In addition, a positive correlation between ZEB1-AS1 and ZEB1 (zinc finger E-box binding homeobox 1) gene expression was verified in primary and metastatic melanomas. Using gene expression signatures indicative of invasive or proliferative phenotypes, we found an association between ZEB1-AS1 upregulation and a transcriptional profile for invasiveness. Enrichment analysis of correlated genes demonstrated cancer genes and pathways associated with ZEB1-AS1. We suggest that the lncRNA ZEB1-AS1 could function by activating ZEB1 gene expression, thereby influencing invasiveness and phenotype switching in melanoma, an epithelial-to-mesenchymal transition (EMT)-like process, which the ZEB1 gene has an essential role.

Long non-coding RNA ZEB2-AS1 promotes the proliferation, metastasis and epithelial mesenchymal transition in triple-negative breast cancer by epigenetically activating ZEB2

The triple‐negative breast cancer is the most malignant type of breast cancer. Its pathogenesis and prognosis remain poor despite the significant advances in breast cancer diagnosis and therapy. Meanwhile, long noncoding RNAs (LncRNAs) play a pivotal role in the progression of malignant tumors. In this study, we found that LncRNA‐ZEB2‐AS1 was dramatically up‐regulated in our breast cancer specimens and cells (MDA231), especially in metastatic tumor specimens and highly invasive cells, and high lncRNA‐ZEB2‐AS1 expression is associated with clinicopathologic features and short survival of breast cancer patients. LncRNA‐ZEB2‐AS1 promotes the proliferation and metastasis of MDA231 cells in SCID mice. Thus, it is regarded as an oncogene in triple‐negative breast cancer. It is mainly endo‐nuclear and situated near ZEB2, positively regulating ZEB2 expression and activating the epithelial mesenchymal transition via the PI3K/Akt/GSK3β/Zeb2 signaling pathway. Meanwhile, EGF‐induced F‐actin polymerization in MDA231 cells can be suppressed by reducing lncRNA‐ZEB2‐AS1 expression. The migration and invasion of triple‐negative breast cancer can be altered through cytoskeleton rearrangement. In summary, we demonstrated that lncRNA‐ZEB2‐AS1 is an important factor affecting the development of triple‐negative breast cancer and thus a potential oncogene target.

ZEB1 promotes tumorigenesis and metastasis in hepatocellular carcinoma by regulating the expression of vimentin

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide and its prognosis remains poor. Epithelial‑to‑mesenchymal transition (EMT)‑induced markers have emerged as key regulators of tumor development and progression in HCC. The aim of the present study was to investigate the role of zinc finger E‑box‑binding homeobox 1 (ZEB1) in the tumorigenesis of HCC and to elucidate the mechanism underlying the correlation between ZEB1 and vimentin (VIM). The expression levels of ZEB1 and VIM were assessed by immunohistochemistry, western blotting and reverse transcription‑quantitative polymerase chain reaction analysis in HCC tissues and cell lines. The biological significance of ZEB1 was examined by downregulating the expression of ZEB1 in Huh‑7 cells. A luciferase reporter assay was used to investigate the association between ZEB1 and VIM. The expression levels of ZEB1 and VIM were higher in tumor tissues compared with those in adjacent normal tissues, and they were significantly associated with a poor prognosis in patients with HCC, whereas ZEB1 silencing led to the attenuation of HCC cell proliferation, invasion and migration. Furthermore, it was observed that ZEB1 was able to bind to a certain site in the VIM promoter and regulate the transcriptional activity of VIM. Therefore, the present study demonstrated that ZEB1 is a potential biomarker of the tumorigenesis and progression of HCC, and it may regulate transcription of the VIM gene.

Expression of Epithelial-Mesenchymal Transition Proteins in Pancreatic Anaplastic (Undifferentiated) Carcinoma

OBJECTIVES

The aim of this study was to identify an association of pancreatic anaplastic carcinoma (APC) with the epithelial-mesenchymal transition (EMT).

METHODS

Resected APCs (n = 24) were examined to assess components of APCs, including carcinomatous, transitional, and sarcomatous regions. Analysis was performed based on the immunoreactivity of E-cadherin and 3 EMT-related proteins: Slug (zinc finger protein SNAI2), Twist (Twist-related protein 1), and Zeb1 (zinc finger E-box-binding homeobox 1). Expression score was determined based on staining intensity and stained area of the target cells. Finally, we performed a hierarchical clustering based on the expression pattern of E-cadherin and EMT-related proteins of the sarcomatous component.

RESULTS

The expression score of E-cadherin decreased in the order of sarcomatous > transitional > carcinomatous components (P < 0.01). Although there were significant differences in the immunohistochemical scores of Slug, Twist, and Zeb1 between carcinomatous and transitional components (P < 0.01), the significant difference in immunohistochemical score of Zeb1 between transitional and sarcomatous components was found (P < 0.05). Furthermore, APCs were divided into 2 subgroups based on the expression patterns of E-cadherin and EMT-related proteins (hierarchical clustering analysis). Consequently, these subgroups were distinguished by Twist expression.

CONCLUSIONS

Epithelial-mesenchymal transition plays an essential role in the pathogenesis of APC.

The roles of ZEB1 in tumorigenic progression and epigenetic modifications

Highly expressed Zinc-finger E-box binding protein 1 (ZEB1) is significantly associated with the malignancy of various cancers. Signal transduction and activation of ZEB1 play important roles in cancer transformation and epithelial-mesenchymal transition (EMT). Emerging evidence suggests that ZEB1 drives the induction of EMT with activation of stem cell traits, immune evasion and epigenetic reprogramming. As an ideal target for EMT research, ZEB1 has been extensively studied for decades. However, the link between ZEB1 and epigenetic regulation of EMT has only recently been discovered. ZEB1 facilitates the epigenetic silencing of E-cadherin by recruiting multiple chromatin enzymes of E-cadherin promoter, such as histone deacetylases (HDACs), DNA methyltransferase (DNMT) and ubiquitin ligase. Destruction of the connection between ZEB1 and these chromatin-modifying enzymes may represent an efficient for treating cancer. In this review, we outlined the biological function of ZEB1 in tumorigenic progression and epigenetic modifications and elucidate its transcriptional network, which is a suitable potential target for the design of novel anticancer drugs.

Entinostat reverses P-glycoprotein activation in snail-overexpressing adenocarcinoma HCC827 cells

Epithelial-to-mesenchymal transition (EMT) in cancer cells facilitates tumor progression by promoting invasion and metastasis. Snail is a transcriptional factor that induces EMT, while P-glycoprotein (P-gp) is an efflux transporter involved in anticancer drug resistance, and P-gp efflux activity is stimulated in Snail-overexpressing lung cancer cells with EMT characteristics. Since the histone deacetylase (HDAC) inhibitor entinostat (Ent) reverses EMT features, our aim in this study was to determine whether Ent also suppresses P-gp activation in Snail-induced cells. First, we confirmed that Ent treatment reduced migration activity, downregulated E-cadherin and upregulated vimentin at the mRNA level in Snail-overexpressing cells, thus inhibiting EMT. Efflux and uptake assays using rhodamine123 (Rho123), a fluorescent P-gp substrate, showed that Ent also inhibited Snail-induced activation of P-gp. Moreover, P-gp activity was more strongly inhibited by Ent in Snail-overexpressing cells than in Mock cells. When we evaluated the uptakes of Rho123 by LLC-PK1 cells and P-gp-overexpressing LLC-GA5COL150 cells, Rho123 accumulation in LLC-GA5COL150 cells was significantly decreased compared with that in LLC-PK1 cells. Coincubation with Ent had no effect on Rho123 accumulation in either of the cell lines. Thus, Ent appears to be an inhibitor, but not a substrate, of P-gp at low concentration. Our results suggest that Ent treatment might suppress not only Snail-induced cancer malignant alteration, but also P-gp-mediated multidrug resistance.

TMPRSS4 induces invasion and proliferation of prostate cancer cells through induction of Slug and cyclin D1

TMPRSS4 is a novel type II transmembrane serine protease found at the cell surface that is highly expressed in pancreatic, colon, and other cancer tissues. Previously, we demonstrated that TMPRSS4 mediates tumor cell invasion, migration, and metastasis. We also found that TMPRSS4 activates the transcription factor activating protein-1 (AP-1) to induce cancer cell invasion. Here, we explored TMPRSS4-mediated cellular functions and the underlying mechanisms. TMPRSS4 induced Slug, an epithelial-mesenchymal transition (EMT)-inducing transcription factor, and cyclin D1 through activation of AP-1, composed of c-Jun and activating transcription factor (ATF)-2, which resulted in enhanced invasion and proliferation of PC3 prostate cancer cells. In PC3 cells, not only c-Jun but also Slug was required for TMPRSS4-mediated proliferation and invasion. Interestingly, Slug induced phosphorylation of c-Jun and ATF-2 to activate AP-1 through upregulation of Axl, establishing a positive feedback loop between Slug and AP-1, and thus induced cyclin D1, leading to enhanced proliferation. Using data from The Cancer Genome Atlas, we found that Slug expression positively correlated with that of c-Jun and cyclin D1 in human prostate cancers. Expression of Slug was positively correlated with that of cyclin D1 in various cancer cell lines, whereas expression of other EMT-inducing transcription factors was not. This study demonstrates that TMPRSS4 modulates both invasion and proliferation via Slug and cyclin D1, which is a previously unrecognized pathway that may regulate metastasis and cancer progression.

Long non-coding RNA ZEB2-AS1 promotes proliferation and inhibits apoptosis in human lung cancer cells

Lung cancer is among the leading causes of cancer-associated mortality worldwide, with a low 5-year survival rate of 16.1%. However, the underlying molecular mechanisms behind lung cancer tumorigenesis remain largely unknown. Long non-coding RNAs (lncRNAs) have been demonstrated to serve a function in the tumorigenesis of multiple types of cancer. The objective of the present study was to identify the function of a newly identified lncRNA zinc finger E-box-binding homeobox 2 antisense RNA 1 (ZEB2-AS1) in human lung cancer. Results demonstrated that the transcript level of ZEB2-AS1 in human lung cancer was markedly upregulated in vivo and in vitro. The knockdown of ZEB2-AS1 in A549 and NCI-H292 cells, and the overexpression of ZEB2-AS1 in H-125 and H1975 cells, altered colony formation and cell proliferative rate, as examined using colony formation and cell proliferation assays. Western blot analysis revealed that the knockdown of ZEB2-AS1 in A549 and NCI-H292 cells increased the protein levels of B-cell lymphoma 2 (Bcl-2), Bcl-2-associated X protein (Bax), caspase-3 and -9, upregulated the relative activities of caspase-3 and -9, and had no observable effect on caspase-8 activity. Similarly, the overexpression of ZEB2-AS1 in H-125 and H1975 cells resulted in decreased expression of caspase-3, caspase-9, Bcl-2 and Bax. The results identified the effects of lncRNA ZEB2-AS1 on lung cancer progression through promoting its proliferation and inhibiting cell apoptosis, indicating that ZEB2-AS1 may serve as a novel prognostic factor for the diagnosis and treatment of human lung cancer in the clinic.

Loss of ZFP36 expression in colorectal cancer correlates to wnt/ ß-catenin activity and enhances epithelial-to-mesenchymal transition through upregulation of ZEB1, SOX9 and MACC1

The mRNA-destabilizing protein ZFP36 has been previously described as a tumor suppressor whose expression is lost during colorectal cancer development. In order to evaluate its role in this disease, we restored ZFP36 expression in different cell contexts, showing that the presence of this protein impairs the epithelial-to-mesenchymal transition (EMT) and induces a higher susceptibility to anoikis. Consistently, we found that ZFP36 inhibits the expression of three key transcription factors involved in EMT: ZEB1, MACC1 and SOX9. Finally, we observed for the first time that its expression negatively correlates with the activity of Wnt/β-catenin pathway, which is constitutively activated in colorectal cancer. This evidence provides a clue on the mechanism leading to the loss of ZFP36 in CRC.

Diversity and functional evolution of the plasminogen activator system

The urokinase plasminogen activator system is a family of serine proteases which consists of uPA (urokinase plasminogen activator), uPAR (urokinase type plasminogen activator receptor) and PAI-1 (plasminogen activator inhibitor 1). In addition to their significant roles in activation, these proteases act as key regulators of the tumor microenvironment and are involved in the metastatic process in many cancers. High levels of uPA system proteases in many human cancer predicts poor patient prognosis and strongly indicated a key role of uPA system in cancer metastasis. Individual components of uPA system are found to be differentially expressed in cancer cells compared to normal cells and therefore are potential therapeutic targets. In this review, we present the molecular and cellular mechanisms underlying the role of uPA system in cancer progression. Epithelial to mesenchymal transitions (EMT) is the main cause of the cancer cell metastasis. We have also attempted to relate the role of uPA signaling in EMT of cancer cells.

Regulation of EMT in Colorectal Cancer: A Culprit in Metastasis

Epithelial to mesenchymal transition (EMT) is a process during which cells lose their epithelial characteristics, for instance cell polarity and cell-cell contact, and gain mesenchymal properties, such as increased motility. In colorectal cancer (CRC), EMT is associated with an invasive or metastatic phenotype. In this review, we discuss recent studies exploring novel regulation mechanisms of EMT in CRC, including the identification of new CRC EMT regulators. Upregulation of inducers can promote EMT, leading to increased invasiveness and metastasis in CRC. These inducers can downregulate E-cadherin and upregulate N-cadherin and vimentin (VIM) through modulating EMT-related signaling pathways, for instance WNT/β-catenin and TGF-β, and EMT transcription factors, such as zinc finger E-box binding homeobox 1 (ZEB1) and ZEB2. In addition, several microRNAs (miRNAs), including members of the miR-34 and miR-200 families, are found to target mRNAs of EMT-transcription factors, for example ZEB1, ZEB2, or SNAIL. Downregulation of these miRNAs is associated with distant metastasis and advanced stage tumors. Furthermore, the role of EMT in circulating tumor cells (CTCs) is also discussed. Mesenchymal markers on the surface of EMT CTCs were found to be associated with metastasis and could serve as potential biomarkers for metastasis. Altogether, these studies indicate that EMT is orchestrated by a complicated network, involving regulators of different signaling pathways. Further studies are required to understand the mechanisms underlying EMT in CRC.

Simple classifiers for molecular subtypes of colorectal cancer

BACKGROUND AND STUDY AIM

Colorectal cancer (CRC) is a heterogeneous disease entity with a diverse biological pathogenesis. This study aims to validate the two studies published in 2013 which established a separate CRC molecular subtype classification by utilizing a rapidly accessible miniclassifier, and verify a simplified version thereof.

PATIENTS AND METHODS

Participants diagnosed with CRC (n = 568) were subtyped in three classifications for characteristic, and prognostic purposes. Colorectal cancer subtypes (CCS) were classified as: i) CCS1 (CDX2+, microsatellite stable (MSS)/microsatellite instability (MSI)-low), ii) CCS2 (MSI-high), and iii) CCS3 (FRMD6/ZEB1/HTR2B +, CDX2-, MSS/MSI-low]. Simplified CCS (SiCCS) subtypes were grouped as: i) CDX2 (CDX2+, MSS/MSI-low, ZEB1 ≤ 2), ii) MSI-H (MSI-high, CDX2/FRMD6/ZEB1/HTR2B +/-), and iii) ZEB1 (ZEB1 ≥ 2, CDX2-, MSS/MSI-low). New molecular classification (NMC) subtypes were defined as: i) enterocyte (E-C) (MUC2 +), ii) goblet-like (G-L) (MUC2 + and TFF3 +), iii) transit-amplifying (T-A) (CFTR +), and iv) stem-like (S-L) (ZEB1 +).

RESULTS

In total, 53.5% (n = 304) CCS, 58.3% (n = 331) SiCCS, and 37.7% (n = 214) NMC tumours could be evaluated. CCS2 and MSI-H CRCs had the most favourable survival outcome, whereas the CCS3, ZEB1 and S-L subtypes showed the poorest prognosis. A significant overlap between CCS3, ZEB1, and S-L tumours was demonstrated.

CONCLUSION

There is still a need for a consensus gene expression-based subtyping classification system for CRCs, thereby allowing the categorization of most CRC tumours. This study reveals that a simple and rapidly accessible process could replace the complicated, costly and mostly inapproachable methods clinical practices that have been introduced in the majority of previous studies.

ZEB1 Mediates Drug Resistance and EMT in p300-Deficient CRC

We discuss the hypothesis that ZEB1-Wnt-p300 signaling integrates epithelial to mesenchymal transition (EMT) and resistance to histone deacetylase inhibitors (HDACis) in colorectal cancer (CRC) cells. The HDACi butyrate, derived from dietary fiber, has been linked to CRC prevention, and other HDACis have been proposed as therapeutic agents against CRC. We have previously discussed that resistance to butyrate likely contributes to colonic carcinogenesis, and we have demonstrated that butyrate resistance leads to cross-resistance to cancer therapeutic HDACis. Deregulated Wnt signaling is the major initiating event in most CRC cases. One mechanism whereby butyrate and other HDACis exert their anti-CRC effects is via Wnt signaling hyperactivation, which promotes CRC cell apoptosis. The histone acetylases (HATs) CBP and p300 are mediators of Wnt transcriptional activity, and play divergent roles in the downstream consequences of Wnt signaling. CBP-mediated Wnt signaling is associated with cell proliferation and stem cell maintenance; whereas, p300-mediated Wnt activity is associated with differentiation. We have found that CBP and p300 differentially affect the ability of butyrate to influence Wnt signaling, apoptosis, and proliferation. ZEB1 is a Wnt signaling-targeted gene, whose product is a transcription factor expressed at the invasive front of carcinomas where it promotes malignant progression and EMT. ZEB1 is typically a transcriptional repressor; however, when associated with p300, ZEB1 enhances transcription. These changes in ZEB1 activity likely affect the cancer cell phenotype. ZEB1 has been shown to promote resistance to chemotherapeutic agents, and expression of ZEB1 is upregulated in butyrate-resistant CRC cells that lack p300 expression. Since the expression of ZEB1 correlates with poor outcomes in cancer, ZEB represents a relevant therapeutic target. Here we propose that targeting the signaling network established by ZEB1, Wnt signaling, and p300 signaling can reverse HDACi resistance and inhibit EMT.

The miR-200b-ZEB1 circuit regulates diverse stemness of human hepatocellular carcinoma

Accumulating evidence suggests that human hepatocellular carcinoma (HCC) can be derived from cancer stem cells (CSCs), which contribute to tumor initiation, metastasis, chemoresistance, and recurrence. A great variety of HCC CSCs resulting in diverse clinical manifestations have been reported. However, how CSC diversity is regulated and generated remains unclear. Here we report that the miR-200b-ZEB1 circuit is closely involved with the induction and maintenance of a diverse group of CSCs. We found that miR-200b downregulation occurred in early HCC and associated with poor prognosis. The downregulation was attributable to genome deletion and promoter methylation of the miR-200a/b/429 gene. Ectopic expression of miR-200b or silencing of ZEB1 led to a decrease in CD13⁺ and CD24⁺ HCC CSCs and an increase in EpCAM⁺ HCC CSCs. Mechanistically, miR-200b directly suppressed BMI1 and ZEB1 expressions. ZEB1 recognized promoters of CD13, CD24, and EpCAM genes resulting in CD13 and CD24 upregulation and EpCAM downregulation. Neither miR-200b nor ZEB1 had obvious effects on CD133 or CD90 expression. Silencing CD13 or CD24 expression suppressed tumorigenicity of HCC cells. Ectopic expression of CD24 reversed the suppression of tumorigenicity by ectopic expression of miR-200b. Clinically, miR-200b downregulation was coupled with ZEB1 upregulation in approximately two-thirds of HCC patients. ZEB1 expression was positively correlated with CD13 and CD24 expressions in HCCs, while miR-200b expression was positively correlated with EpCAM. Our findings suggest that the miR-200b-ZEB1 circuit is a master regulator of diverse stemness of HCC, which differentiates HCCs into those containing CD13⁺ /CD24⁺ CSCs from those containing EpCAM⁺ CSCs.

Sodium Salicylate Inhibits Urokinase Activity in MDA MB-231 Breast Cancer Cells

INTRODUCTION

Sodium salicylate (NaS) is a derivate of acetylsalicylic acid or aspirin, used as a nonsteroidal anti-inflammatory drug for centuries, for its analgesic and anti-inflammatory effects. It was found to modulate different signaling pathways, in a cell-specific way. Here, we explore the effect of NaS on cell growth and urokinase activity in MDA MB-231 breast cancer cells.

MATERIALS AND METHODS

We analyzed the effect of NaS treatment on cell growth by flow cytometry and viability test. The transwell migration assay was used to study the migratory response of the cells. The gene expression was analyzed by qRT-PCR on RNA level and by Western blot analysis on protein level. Urokinase activity was assessed by caseinolysis.

RESULTS

Sublethal concentrations of NaS decreased cell growth and inhibited urokinase activity. The latter was a consequence of decrease in urokinase expression and increase in expression of its inhibitors. Analysis of signaling molecules revealed activation of transforming growth factor-β signaling, increase in master transcription factors for epithelial-mesenchymal transition and changes in integrin expression.

CONCLUSIONS

We propose that NaS causes partial cellular reprogramming through transforming growth factor-β signaling which, together with direct NaS influence, causes changes in expression in a set of genes involved in extracellular proteolysis. These data could be beneficial for the development of new therapeutic approaches in invasive breast cancer treatment.

Tumor Budding, uPA, and PAI-1 in Colorectal Cancer: Update of a Prospective Study

Aims. The prognostic role of the proteases uPA and PAI-1, as well as tumor budding, in colon cancer, has been investigated previously. Methods. We provide 6-year follow-up data and results of the validation set. The initial test set and validation set consisted of 55 colon cancers and 68 colorectal cancers, respectively. Tissue samples were analyzed for uPA and PAI-1 using a commercially available Enzyme-Linked Immunosorbent Assay (ELISA). Tumor budding was analyzed on cytokeratin-stained slides. Survival analyses were performed using cut-offs that were determined previously. Results. uPA was not prognostic for outcome. PAI-1 showed a trend towards reduced cancer specific survival in PAI-1 high-grade cases (68 versus 83 months; P = 0.091). The combination of high-grade PAI-1 and tumor budding was associated with significantly reduced cancer specific survival (60 versus 83 months; P = 0.021). After pooling the data from both sets, multivariate analyses revealed that the factors pN-stage, V-stage, and a combination of tumor budding and PAI-1 were independently prognostic for the association with distant metastases. Conclusions. A synergistic adverse effect of PAI-1 and tumor budding in uni- and multivariable analyses was found. PAI-1 could serve as a target for anticancer therapy.

Heavy metal pollutant cadmium enhances malignant biological behavior of human colorectal carcinoma HCT-116 cells via inducing epithelial-mesenchymal transition

AIM

To investigate the influence of cadmium on the malignant biological behavior of HCT-116 cells and the mechanism involved.

METHODS

After HCT-116 cells were treated with cadmium, the changes in cell malignant biological behavior were assessed by MTT assay, colony forming assay, cell adhesion assay, and transwell migration and invasion assays. Western blot was used to detect the expression of E-cadherin, Vimentin, Zinc finger E-box binding homeobox1, MMP-3, MMP-9 and other proteins in cadmium treated cells.

RESULTS

Chronic exposure to cadmium enhanced the malignant biological behavior of HCT-116 cells, and the transformed cells formed mesenchymal-like intercellular junctions. The protein expression of vimentin, MMP3, and MMP9 was increased, while the expression of E-cadherin was decreased in a time-dependent manner. Overall, morphological and molecular changes suggested that HCT-116 cells underwent an epithelial-mesenchymal transition (EMT) process after chronic cadmium exposure.

CONCLUSION

Cadmium enhances the malignant biologic behavior of HCT-116 cells possibly by inducing EMT.

Downregulation of ZEB2-AS1 decreased tumor growth and metastasis in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) remains one of the most common types of cancer worldwide and prognosis remains poor. Previous studies have suggested that long non-coding RNAs (lncRNAs) may be key regulators of tumor development and progression in HCC. It has been determined that 61–72% of transcribed regions contain lncRNAs in the antisense orientation (aslncRNAs). However, the function of aslncRNAs in HCC remains to be elucidated. The present study investigated the function of the aslncRNA zinc finger E-box binding homeobox 2 antisense RNA 1 (ZEB2-AS1) in 40 HCC tissues and 5 different human HCC cell lines using reverse transcription-quantitative polymerase chain reaction. Additionally, the expression levels of ZEB2-AS1 were downregulated by transfection of small interfering RNAs (siRNAs) to determine whether ZEB2-AS1 is capable of affecting cell proliferation, invasion and metastasis by regulating ZEB2, vimentin, fibronectin, E-cadherin and N-cadherin expression levels. The results of the present study demonstrated that the expression levels of ZEB2-AS1 were greater in HCC tissues when compared with the adjacent normal tissues. Furthermore, ZEB2-AS1 expression was significantly associated with the size of the primary tumor, intrahepatic metastasis and tumor-node-metastasis stage. The Kaplan-Meier survival curves suggested that patients with high ZEB2-AS1 expression levels experienced the lowest overall and recurrence-free survival rates compared with those that had low expression levels. In addition, the current study demonstrated that the downregulation of ZEB2-AS1 was associated with decreased tumor growth and metastasis in HCC by the regulation of the expression levels of epithelial mesenchymal transition-induced markers. In conclusion, lncRNA ZEB2-AS1 may be used as a valuable biomarker in patients with HCC.

Zinc finger E-box binding homeobox-1 (Zeb1) drives anterograde lysosome trafficking and tumor cell invasion via upregulation of Na+/H+ Exchanger-1 (NHE1)

Tumor cell invasion through the extracellular matrix is facilitated by the secretion of lysosome-associated proteases. As a common mechanism for secretion, lysosomes must first traffic to the cell periphery (anterograde trafficking), consistent with invasive cells often containing lysosomes closer to the plasma membrane compared to non-invasive cells. Epithelial to mesenchymal transition (EMT) is a transcriptionally driven program that promotes an invasive phenotype, and Zeb1 is one transcription factor that activates the mesenchymal gene expression program. The role of lysosome trafficking in EMT-driven invasion has not been previously investigated. We found that cells with increased levels of Zeb1 displayed lysosomes located closer to the cell periphery and demonstrated increased protease secretion and invasion in 3-dimensional (3D) cultures compared to their epithelial counterparts. Additionally, preventing anterograde lysosome trafficking via pharmacological inhibition of Na+/H+ exchanger 1 (NHE1) or shRNA depletion of ADP-ribosylation like protein 8b (Arl8b) reversed the invasive phenotype of mesenchymal cells, thus supporting a role for lysosome positioning in EMT-mediated tumor cell invasion. Immunoblot revealed that expression of Na+/H+ exchanger 1 correlated with Zeb1 expression. Furthermore, we found that the transcription factor Zeb1 binds to the Na+/H+ exchanger 1 promoter, suggesting that Zeb1 directly controls Na+/H+ transcription. Collectively, these results provide insight into a novel mechanism regulating Na+/H+ exchanger 1 expression and support a role for anterograde lysosome trafficking in Zeb1-driven cancer progression. © 2016 Wiley Periodicals, Inc.

Mechanism, Consequences, and Therapeutic Targeting of Abnormal IL15 Signaling in Cutaneous T-cell Lymphoma

Cutaneous T-cell lymphoma (CTCL) is the most common type of primary cutaneous lymphoma. Here, we report that patients with CTCL show increased IL15 in a clinical stage-dependent manner. Mechanistically, we show that ZEB1 is a transcriptional repressor of IL15 in T cells and that hypermethylation of the ZEB1 binding region within the IL15 promoter, as seen in patients with CTCL, prevents ZEB1 binding and causes increased transcription of IL15 Using a transgenic mouse model of IL15, we provide evidence that overexpression of IL15 induces a spontaneous CTCL that mimics the human neoplasm. Excessive autocrine production of IL15 in T cells inhibits an HDAC1-mediated negative autoregulatory loop, resulting in the upregulation of HDAC1 and HDAC6 and transcriptional induction of the onco-miR-21. Interruption of IL15 downstream signaling with isotype-specific HDAC inhibitors halts (HDAC1) or significantly delays (HDAC6) the progression of CTCL in vivo and provides preclinical evidence supporting a hierarchical model of oncogenic signaling in CTCL.

SIGNIFICANCE

To date, CTCL pathogenesis remains unknown, and there are no curative therapies. Our findings not only demonstrate a critical role for IL15-mediated inflammation in cutaneous T-cell lymphomagenesis, but also uncover a new oncogenic regulatory loop in CTCL involving IL15, HDAC1, HDAC6, and miR-21 that shows differential sensitivity to isotype-specific HDAC inhibitors. Cancer Discov; 6(9); 986-1005. ©2016 AACR.This article is highlighted in the In This Issue feature, p. 932.

MLL-AF9 Expression in Hematopoietic Stem Cells Drives a Highly Invasive AML Expressing EMT-Related Genes Linked to Poor Outcome

To address the impact of cellular origin on acute myeloid leukemia (AML), we generated an inducible transgenic mouse model for MLL-AF9-driven leukemia. MLL-AF9 expression in long-term hematopoietic stem cells (LT-HSC) in vitro resulted in dispersed clonogenic growth and expression of genes involved in migration and invasion. In vivo, 20% LT-HSC-derived AML were particularly aggressive with extensive tissue infiltration, chemoresistance, and expressed genes related to epithelial-mesenchymal transition (EMT) in solid cancers. Knockdown of the EMT regulator ZEB1 significantly reduced leukemic blast invasion. By classifying mouse and human leukemias according to Evi1/EVI1 and Erg/ERG expression, reflecting aggressiveness and cell of origin, and performing comparative transcriptomics, we identified several EMT-related genes that were significantly associated with poor overall survival of AML patients.

MEF2D Transduces Microenvironment Stimuli to ZEB1 to Promote Epithelial-Mesenchymal Transition and Metastasis in Colorectal Cancer

Epithelial-mesenchymal transition (EMT) is an essential mechanism of metastasis, including in colorectal cancer. Although EMT processes are often triggered in cancer cells by their surrounding microenvironment, how EMT-relevant genes control these processes is not well understood. In multiple types of cancers, the transcription factor MEF2D has been implicated in cell proliferation, but its contributions to metastasis have not been addressed. Here, we show MEF2D is overexpressed in clinical colorectal cancer tissues where its high expression correlates with metastatic process. Functional investigations showed that MEF2D promoted cancer cell invasion and EMT and that it was essential for certain microenvironment signals to induce EMT and metastasis in vivo Mechanistically, MEF2D directly regulated transcription of the EMT driver gene ZEB1 and facilitated histone acetylation at the ZEB1 promoter. More importantly, MEF2D responded to various tumor microenvironment signals and acted as a central integrator transducing multiple signals to activate ZEB1 transcription. Overall, our results define a critical function for MEF2D in upregulating EMT and the metastatic capacity of colorectal cancer cells. Further, they offer new insights into how microenvironment signals activate EMT-relevant genes and deepen the pathophysiologic significance of MEF2D, with potential implications for the prevention and treatment of metastatic colorectal cancer. Cancer Res; 76(17); 5054-67. ©2016 AACR.

The EMT-activator ZEB1 induces bone metastasis associated genes including BMP-inhibitors

Tumor cell invasion, dissemination and metastasis is triggered by an aberrant activation of epithelial-to-mesenchymal transition (EMT), often mediated by the transcription factor ZEB1. Disseminating tumor cells must acquire specific features that allow them to colonize at different organ sites. Here we identify a set of genes that is highly expressed in breast cancer bone metastasis and activated by ZEB1. This gene set includes various secreted factors, e.g. the BMP-inhibitor FST, that are described to reorganize the bone microenvironment. By inactivating BMP-signaling, BMP-inhibitors are well-known to induce osteolysis in development and disease. We here demonstrate that the expression of ZEB1 and BMP-inhibitors is correlated with bone metastasis, but not with brain or lung metastasis of breast cancer patients. In addition, we show that this correlated expression pattern is causally linked, as ZEB1 induces the expression of the BMP-inhibitors NOG, FST and CHRDL1 both by directly increasing their gene transcription, as well as by indirectly suppressing their reduction via miR-200 family members. Consequently, ZEB1 stimulates BMP-inhibitor mediated osteoclast differentiation. These findings suggest that ZEB1 is not only driving EMT, but also contributes to the formation of osteolytic bone metastases in breast cancer.

ZEB1 and TCF4 reciprocally modulate their transcriptional activities to regulate Wnt target gene expression

The canonical Wnt pathway (TCF4/β-catenin) has important roles during normal differentiation and in disease. Some Wnt functions depend on signaling gradients requiring the pathway to be tightly regulated. A key Wnt target is the transcription factor ZEB1 whose expression by cancer cells promotes tumor invasiveness by repressing the expression of epithelial specification markers and activating mesenchymal genes, including a number of Wnt targets such as LAMC2 and uPA. The ability of ZEB1 to activate/repress its target genes depends on its recruitment of corepressors (CtBP, BRG1) or coactivators (p300) although conditions under which ZEB1 binds these cofactors are not elucidated. Here, we show that TCF4 and ZEB1 reciprocally modulate each other's transcriptional activity: ZEB1 enhances TCF4/β-catenin-mediated transcription and, in turn, Wnt signaling switches ZEB1 from a repressor into an activator. In colorectal cancer (CRC) cells with active Wnt signaling, ZEB1 enhances transcriptional activation of LAMC2 and uPA by TCF4/β-catenin. However, in CRC cells with inactive Wnt, ZEB1 represses both genes. Reciprocal modulation of ZEB1 and TCF4 activities involves their binding to DNA and mutual interaction. Wnt signaling turns ZEB1 into an activator by replacing binding of CtBP/BRG1 in favor of p300. Using a mouse model of Wnt-induced intestinal tumorigenesis, we found that downregulation of ZEB1 reduces the expression of LAMC2 in vivo. These results identify a mechanism through which Wnt and ZEB1 transcriptional activities are modulated, offering new approaches in cancer therapy.

JNK-dependent gene regulatory circuitry governs mesenchymal fate

The epithelial to mesenchymal transition (EMT) is a biological process in which cells lose cell–cell contacts and become motile. EMT is used during development, for example, in triggering neural crest migration, and in cancer metastasis. Despite progress, the dynamics of JNK signaling, its role in genomewide transcriptional reprogramming, and involved downstream effectors during EMT remain largely unknown. Here, we show that JNK is not required for initiation, but progression of phenotypic changes associated with EMT. Such dependency resulted from JNK-driven transcriptional reprogramming of critical EMT genes and involved changes in their chromatin state. Furthermore, we identified eight novel JNK-induced transcription factors that were required for proper EMT. Three of these factors were also highly expressed in invasive cancer cells where they function in gene regulation to maintain mesenchymal identity. These factors were also induced during neuronal development and function in neuronal migration in vivo. These comprehensive findings uncovered a kinetically distinct role for the JNK pathway in defining the transcriptome that underlies mesenchymal identity and revealed novel transcription factors that mediate these responses during development and disease.

Epithelial-mesenchymal transition in colorectal cancer metastasis: A system review

Tumor metastasis is a multi-step process by which tumor cells disseminate from their primary site and form secondary tumors at a distant site. And metastasis is the major cause of death in the vast majority of cancer patients. However, the mechanisms underlying each step remain obscure. In the past decade, a developmental program epithelial-to-mesenchymal transition (EMT) has been increasingly recognized to play pivotal and intricate roles in promoting carcinoma invasion and metastasis. The EMT process is very complex and controlled by various families of transcriptional regulators through different signaling pathways. In this system review, we focus on the molecular network of the EMT program and its malignant phenotypes associated with metastasis in colorectal cancer (CRC), including cancer stem cells, tumor budding, circulating tumor cells and drug resistance. A better understanding of the molecular regulation of the dynamic EMT program during tumor metastasis will help to provide much-needed therapeutic interventions to target this program when treating metastatic CRC.

β-arrestin-1 mediates nicotine-induced metastasis through E2F1 target genes that modulate epithelial-mesenchymal transition

Cigarette smoking is a major risk factor in the development of non-small cell lung cancer (NSCLC), which accounts for 80% of all lung cancers. Nicotine, the major addictive component of tobacco smoke, can induce proliferation, invasion, and epithelial-to-mesenchymal transition (EMT) in NSCLC cell lines and promote metastasis of NSCLC in mice. Here, we demonstrate that the scaffolding protein β-arrestin-1 is necessary for nicotine-mediated induction of mesenchymal genes vimentin and fibronectin as well as EMT regulators ZEB1 and ZEB2. Nicotine induced changes in cell morphology and ablate tight junctions consistent with EMT; β-arrestin-1, but not β-arrestin-2, was required for these changes. β-Arrestin-1 promoted the expression of the mesenchymal genes, as well as ZEB1 and ZEB2, through the mediation of the E2F1 transcription factor; this required Src kinase activity. Stimulation of multiple NSCLC cell lines with nicotine led to enhanced recruitment of β-arrestin-1 and E2F1 on vimentin, fibronectin, and ZEB1 and ZEB2 promoters. Furthermore, there was significantly more β-arrestin-1 and E2F1 associated with these promoters in human NSCLC tumors, and β-arrestin-1 levels correlated with vimentin and fibronectin levels in human NSCLC samples. A549-luciferase cells lacking β-arrestin-1 showed a significantly reduced capacity for tumor growth and metastasis when orthotopically implanted into the lungs of SCID-beige mice. Taken together, these studies reveal a novel role for β-arrestin-1 in the growth and metastasis of NSCLC.

Modulation of urokinase plasminogen activator system by poly(ADP-ribose)polymerase-1 inhibition

The urokinase plasminogen activator (uPA) system is a complex regulator of extracellular proteolysis which is involved in various physiological and pathological processes. The major components of this system are the serine protease uPA, two inhibitors PAI-1 and PAI-2, and the receptor uPAR. It has been previously shown by several groups that the uPA system has an important role in cancer progression and therefore its possible prognostic and therapeutic value has been evaluated. The aim of this study is to tackle the role of poly(ADP-ribosyl)ation in the induction of uPA activity in a glioblastoma cell line, A1235. This cell line is sensitive to alkylation damage and is a model for drug treatment. The components of the uPA system and the level of DNA damage were analyzed after alkylation agent treatment in combination with poly(ADP-ribose)polymerase-1 (PARP-1) inhibition. Here we show that the increase in uPA activity results from the net balance change between uPA and its inhibitor at mRNA level. Further, PARP-1 inhibition exerts its influence on uPA activity through DNA damage increase. Involvement of several signaling pathways, as well as cell specific regulation influencing the uPA system are discussed.

Clinical significance of epithelial-mesenchymal transition

The concept of epithelial-mesenchymal transition (EMT), a process where cells change their epithelial towards a mesenchymal phenotype, has gained overwhelming attention especially in the cancer research community. Thousands of scientific reports investigated changes in gene, mRNA and protein expression compatible with EMT and their possible correlation with tumor invasion, metastatic spread or patient prognosis; however, up to now, a proof of clinical significance of the concept is still missing. This review, with a main focus on the role of EMT in tumors, will summarize the basic molecular events underlying EMT including the signaling pathways capable of its induction as well as changes in EMT-associated protein expression and will very briefly touch the role of microRNAs in EMT. We then outline protein markers that are used most frequently for the assessment of EMT in research and diagnostic evaluation of tumor specimens and depict the link between EMT, a cancer stem cell (CSC) phenotype and resistance to conventional antineoplastic therapies. Furthermore, we evaluate a possible correlation between EMT marker expression and patient prognosis as well as current therapeutic concepts targeting the EMT process to slow down or prevent metastatic spread of malignant tumors.

Identification of genes regulating migration and invasion using a new model of metastatic prostate cancer

BACKGROUND

Understanding the complex, multistep process of metastasis remains a major challenge in cancer research. Metastasis models can reveal insights in tumor development and progression and provide tools to test new intervention strategies.

METHODS

To develop a new cancer metastasis model, we used DU145 human prostate cancer cells and performed repeated rounds of orthotopic prostate injection and selection of subsequent lymph node metastases. Tumor growth, metastasis, cell migration and invasion were analyzed. Microarray analysis was used to identify cell migration- and cancer-related genes correlating with metastasis. Selected genes were silenced using siRNA, and their roles in cell migration and invasion were determined in transwell migration and Matrigel invasion assays.

RESULTS

Our in vivo cycling strategy created cell lines with dramatically increased tumorigenesis and increased ability to colonize lymph nodes (DU145LN1-LN4). Prostate tumor xenografts displayed increased vascularization, enlarged podoplanin-positive lymphatic vessels and invasive margins. Microarray analysis revealed gene expression profiles that correlated with metastatic potential. Using gene network analysis we selected 3 significantly upregulated cell movement and cancer related genes for further analysis: EPCAM (epithelial cell adhesion molecule), ITGB4 (integrin β4) and PLAU (urokinase-type plasminogen activator (uPA)). These genes all showed increased protein expression in the more metastatic DU145-LN4 cells compared to the parental DU145. SiRNA knockdown of EpCAM, integrin-β4 or uPA all significantly reduced cell migration in DU145-LN4 cells. In contrast, only uPA siRNA inhibited cell invasion into Matrigel. This role of uPA in cell invasion was confirmed using the uPA inhibitors, amiloride and UK122.

CONCLUSIONS

Our approach has identified genes required for the migration and invasion of metastatic tumor cells, and we propose that our new in vivo model system will be a powerful tool to interrogate the metastatic cascade in prostate cancer.

Role of uPA/uPAR system in tumors

Urokinase type plasminogen activator (uPA) is a major activator of plasminogen, and uPA receptor is the specific receptor of uPA. The uPA/uPAR system regulates plasminogen activity, which participates in degradation and remodeling of the extracellular matrix (ECM), and is involved in many pathophysiological processes. In neoplasms, the activation of plasminogen into plasmin caused by the uPA/uPAR system induces the degradation of components in the basement membrane as well as in the ECM, which provides a favorable microenvironment for tumor invasion and metastasis. In addition, the uPA/uPAR system regulates tumor proliferation and angiogenesis. In this review, we will discuss the role of the uPA/uPAR system in tumors and its potential clinical implications.