TWIST1 and TWIST2 promoter methylation and protein expression in tumor stroma influence the epithelial-mesenchymal transition-like tumor budding phenotype in colorectal cancer

The role of transcription factors in the crosstalk between cancer-associated fibroblasts and tumor cells

BACKGROUND

Transcription factors (TFs) fulfill a critical role in the formation and maintenance of different cell types during the developmental process as well as disease. It is believed that cancer-associated fibroblasts (CAFs) are activation status of tissue-resident fibroblasts or derived from form other cell types via transdifferentiation or dedifferentiation. Despite a subgroup of CAFs exhibit anti-cancer effects, most of them are reported to exert effects on tumor progression, further indicating their heterogeneous origin.

AIM OF REVIEW

This review aimed to summarize and review the roles of TFs in the reciprocal crosstalk between CAFs and tumor cells, discuss the emerging mechanisms, and their roles in cell-fate decision, cellular reprogramming and advancing our understanding of the gene regulatory networks over the period of cancer initiation and progression.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This manuscript delves into the key contributory factors of TFs that are involved in activating CAFs and maintaining their unique states. Additionally, it explores how TFs play a pivotal and multifaceted role in the reciprocal crosstalk between CAFs and tumor cells. This includes their involvement in processes such as epithelial-mesenchymal transition (EMT), proliferation, invasion, and metastasis, as well as metabolic reprogramming. TFs also have a role in constructing an immunosuppressive microenvironment, inducing resistance to radiation and chemotherapy, facilitating angiogenesis, and even 'educating' CAFs to support the malignancies of tumor cells. Furthermore, this manuscript delves into the current status of TF-targeted therapy and considers the future directions of TFs in conjunction with anti-CAFs therapies to address the challenges in clinical cancer treatment.

Deregulation of TWIST1 expression by promoter methylation in gastrointestinal cancers

TWIST1, a basic helix-loop-helix transcription factor with versatile roles in cancer, is frequently deregulated in cancers, through established pathway perturbations. However. the significance of TWIST1 methylation in the deregulation of TWIST1 in gastrointestinal cancers is not fully clear. This study hypothesized that TWIST1 promoter methylation deregulates TWIST1 expression independent of established deregulators such as the WNT, TGFB, NOTCH and miRNA pathways. To prove this hypothesis, colon, gastric and rectal cancer genomic data comprising gene expression, DNA methylation, and miRNA data were retrieved from the Cancer Genome Atlas cohorts which are publicly available in cancer genomic databases, the Genome Data Commons and the cBioportal.org. About 217 variables comprising expression levels of genes of the WNT, TGFB, NOTCH and miRNA signalling pathways, as well as the beta values of 17 TWIST1 methylation loci were subjected to Principal Component Regression Analysis, and then standard Linear Regression Analysis. The results showed that TWIST1 methylation is a predictor of TWIST1 expression in the gastrointestinal cancers, independent of WNT, TGFB, and NOTCH signalling and miRNA deregulation. The results also showed that different TWIST1 methylation loci may deregulate TWIST1 expression in different cancer types. The inference that can be drawn from this study is that TWIST1 DNA methylation is an important TWIST1 deregulation mechanism in colon, rectal and gastric cancers.

Markers of Epithelial-Mesenchymal Transition and Mucinous Histology Are Significant Predictors of Disease Severity and Tumor Characteristics in Early-Onset Colorectal Cancer

Approximately 20% of patients with colorectal cancer (CRC) are diagnosed with a mucinous subtype of this tumor, have a worse prognosis, and often show resistance to available therapies. Molecules from the mucin family are involved in the regulation of epithelial-mesenchymal transition (EMT), which significantly determines the cancer aggressiveness. This study aimed to examine the diagnostic and prognostic significance of mucinous histology and EMT markers in patients with early-onset CRC and their association with disease severity and tumor characteristics. This study included tumor tissue samples from 106 patients diagnosed with CRC before the age of 45, 53 with mucinous and 53 with non-mucinous tumors. The EMT status was determined by immunohistochemical analysis of E-cadherin and Vimentin in tissue sections. Mucinous tumors had significantly higher Mucin-1 (p < 0.001) and cytoplasmic E-cadherin (p = 0.043) scores; they were significantly less differentiated (p = 0.007), more advanced (p = 0.027), and predominately affected right the colon (p = 0.039) compared to non-mucinous tumors. Epithelial tumors were significantly better differentiated (p = 0.034) and with less prominent tumor budding (p < 0.001) than mesenchymal tumors. Mucin-1 and Vimentin were independent predictors of tumor differentiation (p = 0.006) and budding (p = 0.001), respectively. Mucinous histology and EMT markers are significant predictors of disease severity and tumor characteristics in early-onset colorectal cancer.

Identifying a Risk Signature of Methylation-Driven Genes as a Predictor of Survival Outcome for Colon Cancer Patients

Aberrant expression of gene is driven by its promoter methylation and is the key molecular basis of carcinogenic processes. This study aimed at identifying a risk signature of methylation-driven (MD) genes and evaluating its prognostic value for colon cancer (CC) patients. The expression profiles of methylation and mRNA in CC samples were obtained from the TCGA database, and the MethylMix algorithm was used to identify MD genes. The relationships between their expression levels and overall survival (OS) of CC patients were analyzed, and a prognostic signature of MD genes was established. The risk score of gene signature was calculated, and the median was used to divide all patients into high (H) and low (L) risk groups. The prognostic value of gene signature was tested by the TCGA cohort and an independent validation cohort (GSE17538 dataset). In total, 69 MD genes were identified, and 7 were associated with OS of CC patients. Ultimately, 4 (TWIST1, LDOC1, EPHX3, and STC2) were screened out to establish a risk signature. The H-risk patients (>0.923) had a worse OS than L-risk patients (≤0.923) in both the TCGA (5-year cumulative survival: 52.9% vs 72.0%, P=0.005) and GSE17538 cohort (49.4% vs 69.3%, P=0.004). The AUC values of MD genes signature for the prediction of 3- and 5-year OS were 0.648 and 0.643 in the TCGA dataset and 0.634 and 0.624 in the GSE17538 dataset, respectively. The risk signature of four MD genes was identified as an independent predictor of OS for CC patients (HR for TCGA dataset: 2.071, 95% CI=1.196-3.586, P=0.009; HR for GSE17538 dataset: 2.021, 95% CI=1.290-3.166, P=0.002). The risk signature of four MD genes might be a useful prognostic tool and help doctors improve the clinical management of CC patients.

Neighboring macrophage-induced alteration in the phenotype of colorectal cancer cells in the tumor budding area

BACKGROUND

A higher number of tumor buds in the invasive front of colorectal cancer (CRC) specimens has been shown to contribute to a poor prognosis in CRC patients. Because macrophages (Mφs) have been demonstrated to alter the phenotype of cancer cells, we hypothesized that the phenotype of CRC cells in the tumor budding (TB) area might be changed by the interaction between CRC cells and Mφs.

METHODS

We assessed the expression of topoisomerase 1 in CRC cells to estimate the acquisition of chemoresistance in CRC. To demonstrate the tumor-stromal interaction between CRC cells and Mφs, we assessed two histological findings, the number of Mφs per single CRC cell and the proximity between CRC cells and Mφs by histological spatial analysis using HALO software.

RESULTS

The expression levels of topoisomerase 1 in CRC cells were decreased in deeper areas, especially in the TB area, compared to the surface area. Our histological spatial analysis revealed that 2.6 Mφs located within 60 μm of a single CRC cell were required to alter the phenotype of the CRC cell. Double-immunofluorescence staining revealed that higher Mφs were positive for interleukin-6 (IL-6) in the TB area and that AE1/AE3-positive CRC cells were also positive for phospho-STAT3 (pSTAT3) in the TB area; thus, the IL-6 receptor (IL-6R)/STAT3 signaling pathway in CRC cells was upregulated by IL-6 derived from neighboring Mφs.

CONCLUSION

IL-6 secreted from the neighboring Mφs would alter the phenotype of CRC cells via IL-6R/STAT3 signaling pathway.

The Role of Galectin3, Tubulinβ, and Maspin in Promoting Tumor Budding in Colorectal Carcinoma and Their Clinical Implications

Colorectal cancer (CRC) is a leading cause of death worldwide. Despite the advances in surgical and therapeutic management, tumor metastases and poor prognosis are still major problems. Tumor budding is a relevant prognostic factor in CRC, and it can predict tumor metastasis. Galectin3 is responsible for the development and progression of many cancers through the regulation of cell-cell/cell-matrix interactions and tumor cell invasion. Tubulin is a microtubule protein, and maspin is a serine protease inhibitor; both induce tumor cell invasion through the stimulation of epithelial-mesenchymal transition. This study aims to evaluate the relationship between the expression of galecin3, tubulinβ, and maspin in CRC and clinicopathological features, including tumor budding, their prognostic roles, and clinical implications using immunohistochemistry. Galectin3, tubulinβ, and maspin were detected in tumor cells in 95%, 65%, and 87.5% of cases and in stromal cells in 28.8%, 40%, and 0% of cases. High expression of galectin3 and tubulinβ expression either in tumor cells or stroma was significantly associated with aggressive tumor features such as lymph node metastasis, lymphovascular invasion, tumor budding, and advanced tumor stage. The nucleocytoplasmic expression of maspin in tumor cells showed a significant association with deeper tumor invasion, lymph node metastasis, tumor budding, and advanced tumor stage. Significant associations were found between high galectin3 tumor cell expression and nucleocytoplasmic maspin and shorter survival. High expression of galectin3, tubulinβ, and nucleocytoplasmic maspin were significantly associated with aggressive tumor features such as tumor invasion, metastasis, high tumor budding, and short survival in CRC. They could be used as biomarkers for tumor budding and tumor aggressiveness in CRC and may be considered for future target therapy.

The epithelial-mesenchymal plasticity landscape: principles of design and mechanisms of regulation

Epithelial-mesenchymal plasticity (EMP) enables cells to interconvert between several states across the epithelial-mesenchymal landscape, thereby acquiring hybrid epithelial/mesenchymal phenotypic features. This plasticity is crucial for embryonic development and wound healing, but also underlies the acquisition of several malignant traits during cancer progression. Recent research using systems biology and single-cell profiling methods has provided novel insights into the main forces that shape EMP, which include the microenvironment, lineage specification and cell identity, and the genome. Additionally, key roles have emerged for hysteresis (cell memory) and cellular noise, which can drive stochastic transitions between cell states. Here, we review these forces and the distinct but interwoven layers of regulatory control that stabilize EMP states or facilitate epithelial-mesenchymal transitions (EMTs) and discuss the therapeutic potential of manipulating the EMP landscape.

Tumor budding as a potential prognostic marker in determining the behavior of primary liver cancers

Hepatocellular (HCC) and intrahepatic cholangiocarcinoma (ICC), the most common primary tumors of the liver, are among the most important causes of cancer deaths worldwide. Because patients with primary liver tumors are frequently diagnosed at an advanced stage and have high mortality, many efforts have been made to identify new markers to determine their behavior and treatment, similar to those in other solid organ tumors. Recently, morphological assessment of tumor budding (TB) has been revealed as a promising prognostic finding to predict tumor behavior and survival across several different tumor types. Currently, the TB score in colorectal cancer has been revealed as an important parameter in pathology report protocols to determine the course of the disease. Regarding the liver, despite enormous data showing that many mechanisms involved in TB are associated with tumor behavior in both HCC and ICC, studies focusing on the role of TB in predicting the behavior and prognosis of these tumors have started to be investigated very recently. The purpose of this review is to present data about TB in primary tumors of the liver, pointing out the potential role of this parameter in determining the course of the disease, and emphasize the need to increase the number of further studies focusing on the evaluation of this parameter with an overview of the mechanisms involved in TB.

The Transcription Factor Twist1 Has a Significant Role in Mycosis Fungoides (MF) Cell Biology: An RNA Sequencing Study of 40 MF Cases

The purpose of this RNA sequencing study was to investigate the biological mechanism underlying how the transcription factors (TFs) Twist1 and Zeb1 influence the prognosis of mycosis fungoides (MF). We used laser-captured microdissection to dissect malignant T-cells obtained from 40 skin biopsies from 40 MF patients with stage I-IV disease. Immunohistochemistry (IHC) was used to determinate the protein expression levels of Twist1 and Zeb1. Based on RNA sequencing, principal component analysis (PCA), differential expression (DE) analysis, ingenuity pathway analysis (IPA), and hub gene analysis were performed between the high and low Twist1 IHC expression cases. The DNA from 28 samples was used to analyze the TWIST1 promoter methylation level. In the PCA, Twist1 IHC expression seemed to classify cases into different groups. The DE analysis yielded 321 significant genes. In the IPA, 228 significant upstream regulators and 177 significant master regulators/causal networks were identified. In the hub gene analysis, 28 hub genes were found. The methylation level of TWIST1 promoter regions did not correlate with Twist1 protein expression. Zeb1 protein expression did not show any major correlation with global RNA expression in the PCA. Many of the observed genes and pathways associated with high Twist1 expression are known to be involved in immunoregulation, lymphocyte differentiation, and aggressive tumor biology. In conclusion, Twist1 might be an important regulator in the disease progression of MF.

Twist1 Promoter Methylation Regulates the Proliferation and Apoptosis of Acute Myeloid Leukemia Cells via PI3K/AKT Pathway

Twist-related protein 1 (Twist1) is a widely recognized oncogene in acute myeloid leukemia (AML), and its promoter methylation is related with the progression of solid tumors. However, the association between Twist1 promoter methylation and AML has not been well studied. Twist1 mRNA expression was detected using quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of Twist1 and phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signal were measured via western blotting. Methylation-specific PCR was performed to detect the methylation status of Twist1 promoter. CCK-8 assay and flow cytometry were used to reveal cellular biological effects. Twist1 expression and promoter methylation level were significantly upregulated in AML tissues and cell lines and were further downregulated in demethylating agent 5'-azacitidine (5-Aza)-treated cells. Ectopic expression of Twist1 increased AML cell viability, while reducing apoptosis, and attenuated the effects of 5-Aza on the proliferation and apoptosis. We also found that the PI3K/AKT signaling pathway was positively regulated by Twist1. Our findings revealed that Twist1 accelerates the tumorigenesis of AML cells by promoting its promoter methylation via the activation of PI3K/AKT signaling pathway.

The Role of ECM Remodeling, EMT, and Adhesion Molecules in Cancerous Neural Invasion: Changing Perspectives

Perineural invasion (PNI) refers to the cancerous invasion of nerves. It provides an alternative route for metastatic invasion and can exist independently in the absence of lymphatic or vascular invasion. It is a prominent characteristic of specific aggressive malignancies where it correlates with poor prognosis. The clinical significance of PNI is widely recognized despite a lack of understanding of the molecular mechanisms underlying its pathogenesis. The interaction between the nerve and the cancer cells is the most pivotal PNI step which is mediated by the activation or inhibition of multiple signaling pathways that include chemokines, interleukins, nerve growth factors, and matrix metalloproteinases, to name a few. The nerve-cancer cell interaction brings about specific changes in the perineural niche, which not only affects the regular nerve functions, but also enhances the migratory, invasive, and adherent properties of the tumor cells. This review aims to elucidate the vital role of adhesion molecules, extracellular matrix, and epithelial-mesenchymal proteins that promote PNI, which may serve as therapeutic targets in the future.

Genome-wide cross-cancer analysis illustrates the critical role of bimodal miRNA in patient survival and drug responses to PI3K inhibitors

Heterogeneity of cancer means many tumorigenic genes are only aberrantly expressed in a subset of patients and thus follow a bimodal distribution, having two modes of expression within a single population. Traditional statistical techniques that compare sample means between cancer patients and healthy controls fail to detect bimodally expressed genes. We utilize a mixture modeling approach to identify bimodal microRNA (miRNA) across cancers, find consistent sources of heterogeneity, and identify potential oncogenic miRNA that may be used to guide personalized therapies. Pathway analysis was conducted using target genes of the bimodal miRNA to identify potential functional implications in cancer. In vivo overexpression experiments were conducted to elucidate the clinical importance of bimodal miRNA in chemotherapy treatments. In nine types of cancer, tumors consistently displayed greater bimodality than normal tissue. Specifically, in liver and lung cancers, high expression of miR-105 and miR-767 was indicative of poor prognosis. Functional pathway analysis identified target genes of miR-105 and miR-767 enriched in the phosphoinositide-3-kinase (PI3K) pathway, and analysis of over 200 cancer drugs in vitro showed that drugs targeting the same pathway had greater efficacy in cell lines with high miR-105 and miR-767 levels. Overexpression of the two miRNA facilitated response to PI3K inhibitor treatment. We demonstrate that while cancer is marked by considerable genetic heterogeneity, there is between-cancer concordance regarding the particular miRNA that are more variable. Bimodal miRNA are ideal biomarkers that can be used to stratify patients for prognosis and drug response in certain types of cancer.

Bimodal genes can be defined as those having two modes of expression within the same population. A variety of statistical methodologies have been employed to assess bimodal gene expression, but current methods and their applications have been limited. Given the advances in next-generation sequencing as well as the extensive regulatory role of miRNA, assessing bimodality in miRNA-seq data can greatly broaden our understanding of factors underlying tumor progression. The goal of the current study was to utilize a novel mixture modeling approach to identify bimodal miRNA and then demonstrate their importance in cancer by evaluating their ability to predict overall survival and drug response. Our results showed that high levels of bimodal miRNA expression was characteristic of cancer. Additionally, several bimodal miRNA were common to multiple cancer types, suggesting that certain miRNA consistently account for tumor heterogeneity and may be involved in general oncogenic processes. Our study points to the potential of bimodal miRNA to facilitate precise prognostic evaluation and effective treatment strategies.

Investigation of role of CpG methylation in some epithelial mesenchymal transition gene in a chemoresistant ovarian cancer cell line

Ovarian cancer is one of the lethal gynecologic cancers. Chemoresistance is an essential reason for treatment failure and high mortality. Emerging evidence connects epithelial-mesenchymal transition (EMT) like changes and acquisition of chemoresistance in cancers. Including EMT, DNA methylation influences cellular processes. Here, EMT-like changes were investigated in cisplatin-resistant A2780 ovarian cancer cells (A2780cis), wherein role of DNA methylation in some EMT genes regulations was studied. Cell viability assay was carried out to test the sensitivity of A2780, and A2780cis human cancer cell lines to cisplatin. Differential mRNA expression of EMT markers using qPCR was conducted to investigate EMT like changes. CpG methylation role in gene expression regulation was investigated by 5-azacytidine (5-aza) treatment. DNA methylation changes in EMT genes were identified using Methylscreen assay between A2780 and A2780cis cells. In order to evaluate if DNA methylation changes are causally underlying EMT, treatment with 5-aza followed by Cisplatin was done on A2780cis cells. Accordingly, morphological changes were studied under the microscope, whereas EMT marker's gene expression changes were investigated using qPCR. In this respect, A2780cis cell line has maintained its cisplatin tolerance ability and exhibits phenotypic changes congruent with EMT. Methylscreen assay and qPCR study have revealed DNA hypermethylation in promoters of epithelial adhesion molecules CDH1 and EPCAM in A2780cis compared to the cisplatin-sensitive parental cells. These changes were concomitant with gene expression down-regulation. DNA hypomethylation associated with transcription up-regulation of the mesenchymal marker TWIST2 was observed in the resistant cells. Azacytidine treatment confirmed DNA methylation role in regulating gene expression of CDH1, EPCAM and TWIST2 genes. A2780cis cell line undergoes EMT like changes, and EMT genes are regulated by DNA methylation. To that end, a better understanding of the molecular alterations that correlate with chemoresistance may lead to therapeutic benefits such as chemosensitivity restoration.

Twist1 regulates macrophage plasticity to promote renal fibrosis through galectin-3

Renal interstitial fibrosis is the pathological basis of end-stage renal disease, in which the heterogeneity of macrophages in renal microenvironment plays an important role. However, the molecular mechanisms of macrophage plasticity during renal fibrosis progression remain unclear. In this study, we found for the first time that increased expression of Twist1 in macrophages was significantly associated with the severity of renal fibrosis in IgA nephropathy patients and mice with unilateral ureteral obstruction (UUO). Ablation of Twist1 in macrophages markedly alleviated renal tubular injury and renal fibrosis in UUO mice, accompanied by a lower extent of macrophage infiltration and M2 polarization in the kidney. The knockdown of Twist1 inhibited the chemotaxis and migration of macrophages, at least partially, through the CCL2/CCR2 axis. Twist1 downregulation inhibited M2 macrophage polarization and reduced the secretion of the profibrotic factors Arg-1, MR (CD206), IL-10, and TGF-β. Galectin-3 was decreased in the macrophages of the conditional Twist1-deficient mice, and Twist1 was shown to directly activate galectin-3 transcription. Up-regulation of galectin-3 recovered Twist1-mediated M2 macrophage polarization. In conclusion, Twist1/galectin-3 signaling regulates macrophage plasticity (M2 phenotype) and promotes renal fibrosis. This study could suggest new strategies for delaying kidney fibrosis in patients with chronic kidney disease.

Epithelial to Mesenchymal Transition: A Challenging Playground for Translational Research. Current Models and Focus on TWIST1 Relevance and Gastrointestinal Cancers

Resembling the development of cancer by multistep carcinogenesis, the evolution towards metastasis involves several passages, from local invasion and intravasation, encompassing surviving anoikis into the circulation, landing at distant sites and therein establishing colonization, possibly followed by the outgrowth of macroscopic lesions. Within this cascade, epithelial to mesenchymal transition (EMT) works as a pleiotropic program enabling cancer cells to overcome local, systemic, and distant barriers against diffusion by replacing traits and functions of the epithelial signature with mesenchymal-like ones. Along the transition, a full-blown mesenchymal phenotype may not be accomplished. Rather, the plasticity of the program and its dependency on heterotopic signals implies a pendulum with oscillations towards its reversal, that is mesenchymal to epithelial transition. Cells in intermixed E⇔M states can also display stemness, enabling their replication together with the epithelial reversion next to successful distant colonization. If we aim to include the EMT among the hallmarks of cancer that could modify clinical practice, the gap between the results pursued in basic research by animal models and those achieved in translational research by surrogate biomarkers needs to be filled. We review the knowledge on EMT, derived from models and mechanistic studies as well as from translational studies, with an emphasis on gastrointestinal cancers (GI).

Drug resistance in colorectal cancer: An epigenetic overview

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide. Despite significant progress that has been made in therapies against CRC over the past decades, drug resistance is still a major limitation in CRC treatment. Numerous investigations have unequivocally shown that epigenetic regulation plays an important role in CRC drug resistance because of the high rate of epigenetic alterations in multiple genes during cancer development or drug treatment. Furthermore, the reversibility of epigenetic alterations provides novel therapeutic strategies to overcome drug resistance using small molecules, which can target non-coding RNAs or reverse histone modification and DNA methylation. In this review, we discuss epigenetic regulation in CRC drug resistance and the possible role of preventing or reversing CRC drug resistance using epigenetic therapy in CRC treatment.

2b or Not 2b: How Opposing FGF Receptor Splice Variants Are Blocking Progress in Precision Oncology

More than ten thousand peer-reviewed studies have assessed the role of fibroblast growth factors (FGFs) and their receptors (FGFRs) in cancer, but few patients have yet benefited from drugs targeting this molecular family. Strategizing how best to use FGFR-targeted drugs is complicated by multiple variables, including RNA splicing events that alter the affinity of ligands for FGFRs and hence change the outcomes of stromal-epithelial interactions. The effects of splicing are most relevant to FGFR2; expression of the FGFR2b splice isoform can restore apoptotic sensitivity to cancer cells, whereas switching to FGFR2c may drive tumor progression by triggering epithelial-mesenchymal transition. The differentiating and regulatory actions of wild-type FGFR2b contrast with the proliferative actions of FGFR1 and FGFR3, and may be converted to mitogenicity either by splice switching or by silencing of tumor suppressor genes such as CDH1 or PTEN. Exclusive use of small-molecule pan-FGFR inhibitors may thus cause nonselective blockade of FGFR2 isoforms with opposing actions, undermining the rationale of FGFR2 drug targeting. This splice-dependent ability of FGFR2 to switch between tumor-suppressing and -driving functions highlights an unmet oncologic need for isoform-specific drug targeting, e.g., by antibody inhibition of ligand-FGFR2c binding, as well as for more nuanced molecular pathology prediction of FGFR2 actions in different stromal-tumor contexts.

Prognostic Value of TWIST1 and EZH2 Expression in Colon Cancer

BACKGROUND

Colorectal carcinoma (CRC) is the third most common human cancer. Twist, a basic helix-loop-helix (bHLH) transcription factor, is an epithelial-mesenchymal transition ((EMT) inducer that has been involved in carcinogenesis and chemoresistance. Also, the enhancer of Zeste homolologue2 (EZH2), a member of the polycomb group of genes, had been associated with poor prognosis in several malignancies.

OBJECTIVE

To evaluate the expression of Twist1 and EZH2 in colon carcinoma in Egyptian patients and its relation to clinicopathological parameters, prognosis, and survival.

METHODS

Twist1 and EZH2 expressions were evaluated immunohistochemically in 50 cases of colorectal tumors (12 colon adenomas and 38 colon carcinomas) and 20 samples from normal colonic mucosa.

RESULTS

The expression of Twist1 and EZH2 was significantly higher in colon adenoma and carcinoma than that in normal colonic mucosa (P < 0.05). Twist1 and EZH2 expressions were associated with decreased tumor differentiation, advanced stage, and lymph node metastasis. Twist1 and EZH2 expressions were significantly related to 3-year disease-free survival (P = 0.005 and 0.002 respectively) and 3-year overall survival (P = 0.045 and 0.039, respectively).

CONCLUSIONS

Twist1 and EZH2 may serve as prognostic predictors for colon carcinoma and may have a potential role as therapeutic targets in patients with colon carcinoma in the future.

Selective dysregulation of ABC transporters in methotrexate-resistant leukemia T-cells can confer cross-resistance to cytarabine, vincristine and dexamethasone, but not doxorubicin

Pediatric acute lymphoblastic leukemia (pALL) includes 75 % of childhood leukemias, and methotrexate (MTX) is one of the most effective chemotherapy agents prescribed for pALL treatment. The aim of this study was to establish and characterize an MTX-resistant tumor cell model in order to study the mechanism contributing to drug sensitivity loss in pALL. Parental CCRF-CEM cells were treated with a gradual increasing concentration of MTX from 5 nM to 1.28 μM. The resistant subline was then characterized according to the cellular morphology, cellular growth curves and specific mRNA expression changes associated with drug resistance in ALL. Moreover, in vitro cytotoxicity assays were used to analyze cells relative responsiveness to a set of clinically used anti-ALL chemotherapy drugs. The morphological changes observed in the new R-CCRF-CEM/MVCD subline were associated with dysregulation of the EMT-related genes, Twist1 and CDH1. Cells demonstrated downregulation of ABCC1 and the overexpression of ABCA2, ABCA3, and ABCB1 membrane transporters. However, short treatment of the sensitive and parental cell line with MTX did not affect the expression profiles of the former ABC pumps. Moreover, R-CCRF-CEM/MVCD cells demonstrated cross-resistance to cytarabine (cytosine arabinoside, ara-C), vincristine, and dexamethasone, but not doxorubicin. The induced cross-resistance to specific chemotherapy drugs may possibly be attributed to selective dysregulation of the ABC transporters and EMT-related genes. These data may pave the way for the development of new cancer therapeutic strategies.

Tumour budding in solid cancers

Tumour budding is an emerging prognostic biomarker in colorectal cancer (CRC) and other solid cancers. Tumour buds are usually defined as isolated single cancer cells or clusters of up to four cancer cells located at the invasive tumour front. The prognostic value of tumour budding is now supported by a large body of evidence, whereas the utility of this phenotype as a predictive biomarker remains under investigation. The application of tumour budding indices in clinical practice requires a standardized scoring system that can be tailored to specific tumour types and clinical scenarios. In the context of CRC, tumour budding can be assessed according to the method agreed at the International Tumour Budding Consensus Conference (ITBCC) in 2016. Using the ITBCC scoring system, tumour budding is an independent predictor of lymph node metastasis in patients with pT1 CRC and of unfavourable survival in patients with stage II colon cancer. Regardless of the clinical scenario or tumour type, the assertion that 'the more tumour buds, the worse the clinical outcome' applies. In this Review, we provide an overview of tumour budding in solid cancers, highlighting the molecular and biological aspects of this phenomenon, including its associations with epithelial-mesenchymal transition and features of the tumour microenvironment. We also describe the available evidence demonstrating the value of tumour budding as a biomarker across various solid cancers.

DNA methylation-driven EMT is a common mechanism of resistance to various therapeutic agents in cancer

Background

Overcoming therapeutic resistance is one of the major hurdles in cancer care. One mechanism contributing to therapeutic resistance is a process in which epithelial cells switch to a mesenchymal state (epithelial-to-mesenchymal transition or EMT). The precise mechanisms driving EMT-mediated therapeutic resistance have, however, not been elucidated.

Results

Here, we study ten cell line pairs, for which parental cell lines were made resistant to either a targeted or chemotherapy-based treatment. First, we show by miRNA-200 overexpression that treatment resistance is driven by EMT. Next, we demonstrate that DNA methylation changes occur within each cell line pair and show that exposure to 5-azacytidine or knock down of DNA methyltransferases (DNMTs), both of which globally demethylate cells, result in EMT reversal and increased therapeutic sensitivity. This suggests DNA methylation to causally underlie EMT and treatment resistance. We also observe significant overlap in methylation profiles between resistant lines, suggesting a common epigenetic mechanism to cause resistance to therapy. In line with this hypothesis, cross-resistance to other targeted and chemotherapies is observed, while importantly, this is lost upon demethylation of the cells. Finally, we clinically validate that DNA methylation changes drive EMT-mediated resistance to sorafenib in patients with advanced hepatocellular carcinoma (HCC). Specifically, we develop a capture-based protocol to interrogate DNA methylation in low amounts of circulating tumor DNA (ctDNA). By interrogating the methylation status in liquid biopsies, longitudinally collected during sorafenib treatment, we assess whether DNA methylation changes also drive EMT and therapy resistance in a clinical setting. Particularly, by monitoring methylation changes in EMT genes, we are able to predict tumor response and acquired resistance to sorafenib.

Conclusions

We propose methylation changes underlying EMT to constitute a common resistance mechanism to cancer therapies. This process can be reversed pharmacologically and monitored non-invasively in ctDNA to predict resistance to treatment.

Cell Line Derived Xenograft Mouse Models Are a Suitable in vivo Model for Studying Tumor Budding in Colorectal Cancer

Tumor budding (TB) is an important prognostic parameter in colorectal cancer (CRC) and associated with metastasis. However, the mechanisms of TB have not been fully elucidated and a major limitation is the absence of in vivo models. Here, we determine the suitability of human cell line derived xenografts (CDX) as models of TB in CRC. Pan-cytokeratin (CK)-stained next-generation Tissue Microarrays (ngTMA) of two CDX models (HT-29, n = 12 and HCT-8, n = 8) and human CRC (n = 27 high-grade and 25 low-grade budding tumors, each) were evaluated for TB. Immunohistochemistry for E-cadherin, β-catenin, Ki-67, ZEB1, and TWIST1 was performed. HT-29 and HCT-8 were predominantly high-grade and no/low-grade TB tumors, respectively. TB counts in the tumor center (intratumoral budding, ITB) were significantly higher in HT-29 CDX tumors compared to human CRC (p = 0.0099). No difference was found in TB counts at the invasion front (peritumoral budding, PTB; p=0.07). ITB and PTB were strongly correlated (r = 0.438 and r = 0.62 in CDX and human CRC, respectively). Immunohistochemistry profiles were comparable in CDX and human CRC tissues. TB in the CDX mouse models is phenotypically similar to human CRCs and highlights comparable protein profiles. The HT-29 CDX could be a suitable model for the in vivo assessment of TB.

Role of epithelial–mesenchymal transition regulated by twist basic helix-loop-helix transcription factor 2 (Twist2) in embryo implantation in mice

In a previous study we found the expression of epithelial–mesenchymal transition (EMT) biomarkers, including E-cadherin and N-cadherin, was significantly altered in uterine endometrium during embryo implantation via regulation by microRNA (miRNA)-429 and protocadherin-8 (Pcdh8). As a natural continuation of the previous study, the aim of the present study was to explore the role of EMT during embryo implantation and the potential activity of twist basic helix-loop-helix transcription factor 2 (Twist2) in regulating embryo implantation. A pregnancy model was established by naturally mating adult female ICR mice with fertile males. A pseudopregnancy model was established by mating fertile female ICR mice with vasectomised males. An invitro model of embryo implantation was established by the coculture of Ishikawa and JAR spheroids. Endometrial tissue during the peri-implantation period was collected, as were Ishikawa cells, JAR cells and cocultured cells. The expression of EMT markers (E-cadherin, N-cadherin, vimentin and cytokeratin) and Twist2 was detected invivo and invitro using the western blot analysis during embryo implantation. The expression of N-cadherin and vimentin (mesenchymal markers) was upregulated in the invitro implantation model, with downregulation of E-cadherin and cytokeratin (epithelial markers) expression. The expression of N-cadherin, vimentin and Twist2 increased significantly at the implantation sites at the time of implantation (Day 5), whereas the expression of E-cadherin and cytokeratin decreased. Location of Twist2 during embryo implantation was detected by immunohistochemistry (IHC), which revealed that it was extensively expressed in endometrial glandular epithelium and luminal epithelium at implantation sites on Day 5. The effect of the expression of Twist2 on embryo implantation was evaluated by suppressing Twist2 using Twist2-short interference (si) RNA in invivo and invitro models. The numbers of implanted embryos and the implantation rate were compared invivo and invitro. Western blot analysis showed that suppression of Twist2 led to upregulation of E-cadherin and cytokeratin, accompanied by downregulation of N-cadherin and vimentin (P&lt;0.05). The number of implanted embryos after Twist2-siRNA interference was lower than in normal pregnancy (mean (±s.d.) 2.4±0.5 vs 6.8±1.3 respectively; P&lt;0.05). These findings suggest the involvement of EMT in embryo implantation. The suppression of Twist2 could suppress embryo implantation by regulating EMT.

Stomatin plays a suppressor role in non-small cell lung cancer metastasis

Objective

Metastasis is one of the key causes of high mortality in lung cancer. Aberrant DNA methylation is a common event in metastatic lung cancer. We aimed to identify new epigenetic regulation of metastasis-associated genes and characterize their effects on lung cancer progression.

Methods

We screened genes associated with non-small cell lung cancer (NSCLC) metastasis by integrating datasets from the Gene Expression Omnibus (GEO) database. We obtained epigenetic-regulated candidate genes by analyzing the expression profile of demethylation genes. By overlapping analysis, epigenetically modulated metastasis-associated genes were obtained. Kaplan-Meier plotter (KM plotter) was utilized to assess the overall survival (OS) of stomatin in lung cancer. Immunohistochemistry (IHC) was conducted to determine the association between stomatin and metastasis-associated clinical indicators. Both in vitro and in vivo assays were performed to investigate the potential role of stomatin in metastasis. The regulation mechanisms of transforming growth factor β1 (TGFβ1) on stomatin were determined by Sequenom MassARRAY quantitative methylation and western blot assays.

Results

A series of bioinformatic analyses revealed stomatin as the metastasis-associated gene regulated by DNA methylation. The KM plotter analysis showed a positive association between stomatin and the OS of lung cancer. IHC analysis indicated that the decreased stomatin expression is linked with advanced TNM stage. Loss- and gain-of-function experiments displayed that stomatin could inhibit the migration and invasion of NSCLC cells. Furthermore, TGFβ1 repressed stomatin expression during epithelial-to-mesenchymal transition (EMT). The negative correlation between stomatin and TGFβ1 was also validated in advanced stage III lung tumor samples. The underlying mechanism by which TGFβ1 inhibits stomatin is due in part to DNA methylation.

Conclusions

Our results suggest that stomatin may be a target for epigenetic regulation and can be used to prevent metastatic diseases.

Revealing the Critical Regulators of Cell Identity in the Mouse Cell Atlas

Recent progress in single-cell technologies has enabled the identification of all major cell types in mouse. However, for most cell types, the regulatory mechanism underlying their identity remains poorly understood. By computational analysis of the recently published mouse cell atlas data, we have identified 202 regulons whose activities are highly variable across different cell types, and more importantly, predicted a small set of essential regulators for each major cell type in mouse. Systematic validation by automated literature and data mining provides strong additional support for our predictions. Thus, these predictions serve as a valuable resource that would be useful for the broad biological community. Finally, we have built a user-friendly, interactive web portal to enable users to navigate this mouse cell network atlas.

Tumour budding is associated with the mesenchymal colon cancer subtype and RAS/RAF mutations: a study of 1320 colorectal cancers with Consensus Molecular Subgroup (CMS) data

Background

Tumour budding is an important prognostic factor in colorectal cancer (CRC). Molecular profiling of tumour buds suggests (partial) epithelial–mesenchymal transition and cancer stem-cell phenotype, similarly described in the “mesenchymal” Consensus Molecular Subtype 4 (CMS4), which identifies a particularly poor prognostic subgroup. Here, we determine the association of tumour budding with CMS classification, prognosis, and response to therapy.

Methods

AMC-AJCCII-90 cohort (n = 76, stage II) was evaluated for peritumoural budding on H&E slides. LUMC (n = 270, stage I–IV), CAIRO (n = 504, metastatic CRC) and CAIRO2 (n = 472, metastatic CRC) cohorts were investigated for intratumoural budding using pan-cytokeratin-stained tissue microarrays. Budding was scored as count/area, then classified as <5 or ≥5 buds. For all cohorts, CMS classifications were available (gene-expression/immunohistochemistry-based classifiers).

Results

High (≥5) budding predicted a worse outcome in multivariate analysis in AMC-AJCCII-90 (p = 0.018), LUMC (p < 0.0001), and CAIRO (p = 0.03), and in CAIRO2 (continuous variable, p = 0.02). Tumour budding counts were higher in CMS4 compared to epithelial CMS2/3 cancers (p < 0.01, all), and associated with KRAS/BRAF mutations (p < 0.01, AMC-AJCCII-90, CAIRO, CAIRO2).

Conclusion

Tumour budding is an adverse prognostic factor across all CRC stages and is associated with the mesenchymal CMS4 phenotype. KRAS/BRAF mutations are strongly correlated with tumour budding suggesting their involvement in the regulation of this process.

Jiedu Sangen Decoction Inhibits Migration and Invasion of Colon Cancer SW480 Cells via Suppressing Epithelial Mesenchymal Transition

Jiedu Sangen Decoction (JSD), a traditional Chinese medicine (TCM) formula, has been widely used in China to treat gastrointestinal cancer, especially as an adjuvant therapy in colorectal cancer (CRC) patients. This study aimed to evaluate the efficacy of JSD and Jiedu Sangen aqueous extract (JSAE) in colon cancer cells and explored the underlining mechanisms by cytotoxicity assay, scratch assay, transwell migration assay, matrigel invasion assay, confocal laser scanning microscopy, and western blot analysis. We demonstrated that JSAE inhibited the growth of colon cancer SW480 cells in a dose-dependent manner and JSAE repressed cancer cell migration and invasion. Furthermore, epithelial mesenchymal transition (EMT) was reversed by JSAE via enhancing E-cadherin expression and attenuating protein levels of EMT promoting factors such as N-cadherin, Slug, and ZEB1. These findings provided the first experimental evidence confirming the efficacy of JSAE in repressing invasion and metastasis of CRC and paving a way for the broader use of JSD in clinic.

Prognostic role of tumor budding in breast cancer

Tumor budding, defined as a small number of cancer cells observed in pathology sections detached from the main tumor mass, is a common phenomenon in cancer. It is suggested that cells in buds are in the process of actively moving away from the primary tumor in the first step of metastasis. Tumor budding has been observed in a variety of carcinomas and is best studied in colorectal cancers where it portends poor prognosis. More recently, tumor budding was found to be of prognostic significance in other cancers including breast cancer. Tumor budding in breast cancer is associated with other adverse pathologic factors, such as larger tumor size and lymphovascular invasion, but may have additional independent prognostic value. In the future, standardization of the quantification criteria for tumor budding may further aid in its adoption as a prognostic marker.

Cancer cell plasticity: Impact on tumor progression and therapy response

Most tumors exhibit intra-tumor heterogeneity, which is associated with disease progression and an impaired response to therapy. Cancer cell plasticity has been proposed as being an important mechanism that, along with genetic and epigenetic alterations, promotes cancer cell diversity and contributes to intra-tumor heterogeneity. Plasticity endows cancer cells with the capacity to shift dynamically between a differentiated state, with limited tumorigenic potential, and an undifferentiated or cancer stem-like cell (CSC) state, which is responsible for long-term tumor growth. In addition, it confers the ability to transit into distinct CSC states with different competence to invade, disseminate and seed metastasis. Cancer cell plasticity has been linked to the epithelial-to-mesenchymal transition program and relies not only on cell-autonomous mechanisms, but also on signals provided by the tumor microenvironment and/or induced in response to therapy. We provide an overview of the dynamic transition for cancer cell states, the mechanisms governing cell plasticity and their impact on tumor progression, metastasis and therapy response. Understanding the mechanisms involved in cancer cell plasticity will provide insights for establishing new therapeutic interventions.

Tumor budding is associated with poor prognosis of oral squamous cell carcinoma and histologically represents an epithelial-mesenchymal transition process

In this study, we aimed to identify whether tumor budding is associated with the progression and prognosis of oral squamous cell carcinoma (OSCC) and investigate the correlation between tumor budding and regulators of epithelial-mesenchymal transition (EMT). Fifty-six cases of OSCC were selected and their tumor budding status was reviewed using archived hematoxylin and eosin-stained slides. In addition, the expression of EMT regulators was evaluated by immunohistochemistry using antibodies against Snail and Twist. Tumor budding was observed in 19 (33.9%) of the 56 cases of OSCC. Tumor budding was strongly associated with lymph node metastasis (P = .001) and shorter overall survival (P = .002). The expression of Snail and Twist was correlated with lymph node metastasis (P < .001 and .002, respectively) and poorer overall survival (P = .024 and .024, respectively). Tumor budding was significantly associated with the expression of Snail (P = .003) and showed a tendency toward higher expression of Twist (P = .08). Therefore, our results suggest that tumor budding is significantly associated with poor prognosis in patients with OSCC and histologically represents an EMT process in OSCC.

Tumor budding and human chorionic gonadotropin-β expression correlate with unfavorable patient outcome in colorectal carcinoma

Tumor budding is thought to represent a manifestation of epithelial-to-mesenchymal transition (EMT) and it has been correlated with poor patient outcomes in colorectal cancer (CRC). Our group recently demonstrated that human chorionic gonadotropin-β (hCGβ) modulates EMT in CRC. In the current study, based on the likely relationships between tumor budding and hCGβ expression, we examined their clinicopathologic significance in CRC. Twenty-eight of 80 (35.0%) CRC showed tumor budding. Tumor budding significantly correlated with lymph node metastasis (P < 0.01), pathologic stage (P < 0.01), lymphatic invasion (P = 0.044), and vascular invasion (P = 0.013). Thirteen of 80 (16.3%) CRC were hCGβ positive on immunohistochemistry. More tumor buds were present in the hCGβ-positive cases (P < 0.01), and tumor budding was significantly correlated with hCGβ positivity (P < 0.01). Cases with both tumor budding and hCGβ expression had the poorest prognosis compared with all other groups (P < 0.01). In conclusion, tumor budding and hCGβ expression are closely associated with EMT, and they are independent prognostic factors in CRC. They identify patients with an "EMT phenotype" who may respond to targeted molecular therapies.

Upregulation of Twist2 in Non-Muscle Invasive Urothelial Carcinoma of the Bladder Correlate with Response to Treatment and Progression

BACKGROUND:

Twist2 is a transcription factor and an epithelial-to-mesenchymal transition that plays an important role in cell polarity, cell adhesion, and has a role in tumour invasion and metastases.

AIM:

In this study, we examined the expression of Twist2 in non-muscle invasive bladder carcinoma (NMIBC) and correlated the expression with response to treatment and tumour progression.

METHODS:

Data of 305 patients with NMIBC of Ta, T1 were retrieved from hospitals archives. Twist2 expression was examined in tissue samples by immunohistochemistry at initial diagnosis and final follow-up, normal control was 10 normal urothelium, 10 patients with muscle-invasive bladder cancer (MIBC) were a positive control. Treatment of NMIBC was implemented according to the European Association of Urology guidelines on NMIBC. The descriptive statistical analysis included means, standard deviation, p-value; Univariate and multivariate Cox regression analyses.

RESULTS:

Twist2 expression score was identified as negative, low (1-15%); medium (15-40%); and high (40-100%). Patients who had low or low medium scores at the initial diagnosis had a good response and a favourable prognosis. Expression of a high score of Twist2 in patients having high-grade T1 tumours showed non-responsiveness to repeated courses of intravesical bacillus Calmette Guerin (BCG) therapy and was upstaged to MIBC.

CONCLUSION:

Twist2 expression in tissue samples of NMIBC would indicate the tumour response to therapy, upgrading and upstaging in the follow up after intravesical BCG therapy.

TGF-β and the Tissue Microenvironment: Relevance in Fibrosis and Cancer

Transforming growth factor-&beta; (TGF-&beta;) is a cytokine essential for the induction of the fibrotic response and for the activation of the cancer stroma. Strong evidence suggests that a strong cross-talk exists among TGF-&beta; and the tissue extracellular matrix components. TGF-&beta; is stored in the matrix as part of a large latent complex bound to the latent TGF-&beta; binding protein (LTBP) and matrix binding of latent TGF-&beta; complexes, which is required for an adequate TGF-&beta; function. Once TGF-&beta; is activated, it regulates extracellular matrix remodelling and promotes a fibroblast to myofibroblast transition, which is essential in fibrotic processes. This cytokine also acts on other cell types present in the fibrotic and tumour microenvironment, such as epithelial, endothelial cells or macrophages and it contributes to the cancer-associated fibroblast (CAF) phenotype. Furthermore, TGF-&beta; exerts anti-tumour activity by inhibiting the host tumour immunosurveillance. Aim of this review is to update how TGF-&beta; and the tissue microenvironment cooperate to promote the pleiotropic actions that regulate cell responses of different cell types, essential for the development of fibrosis and tumour progression. We discuss recent evidences suggesting the use of TGF-&beta; chemical inhibitors as a new line of defence against fibrotic disorders or cancer.

TGF-β and the Tissue Microenvironment: Relevance in Fibrosis and Cancer

Transforming growth factor-β (TGF-β) is a cytokine essential for the induction of the fibrotic response and for the activation of the cancer stroma. Strong evidence suggests that a strong cross-talk exists among TGF-β and the tissue extracellular matrix components. TGF-β is stored in the matrix as part of a large latent complex bound to the latent TGF-β binding protein (LTBP) and matrix binding of latent TGF-β complexes, which is required for an adequate TGF-β function. Once TGF-β is activated, it regulates extracellular matrix remodelling and promotes a fibroblast to myofibroblast transition, which is essential in fibrotic processes. This cytokine also acts on other cell types present in the fibrotic and tumour microenvironment, such as epithelial, endothelial cells or macrophages and it contributes to the cancer-associated fibroblast (CAF) phenotype. Furthermore, TGF-β exerts anti-tumour activity by inhibiting the host tumour immunosurveillance. Aim of this review is to update how TGF-β and the tissue microenvironment cooperate to promote the pleiotropic actions that regulate cell responses of different cell types, essential for the development of fibrosis and tumour progression. We discuss recent evidences suggesting the use of TGF-β chemical inhibitors as a new line of defence against fibrotic disorders or cancer.

Molecular Detection of EMT Markers in Circulating Tumor Cells from Metastatic Non-Small Cell Lung Cancer Patients: Potential Role in Clinical Practice

Background

Non-small cell lung cancer (NSCLC) is the most common cause of cancer-related mortality; nevertheless, there are few data regarding detection of circulating tumor cells (CTCs) in NSCLC, compared to other kinds of cancers in which their prognostic roles have already been defined. This difference is likely due to detection methods based on the epithelial marker expression which ignore CTCs undergoing epithelial-mesenchymal transition (CTCs^EMT).

Methods

After optimization of the test with spiking experiments of A549 cells undergoing TGF-β1-induced EMT (A549^EMT), the CTCs^EMT were enriched by immunomagnetic depletion of leukocytes and then characterized by a RT-PCR assay based on the retrieval of epithelial and EMT-related genes. Blood samples from ten metastatic NSCLC patients before starting treatment and during chemotherapy were used to test this approach by longitudinal monitoring. Ten age- and sex-matched healthy subjects were also enrolled as controls.

Results

Recovery experiments of spiked A549^EMT cells showed that the RT-PCR assay is a reliable method for detection of CTCs^EMT. CTCs^EMT were detected in three patients at baseline and in six patients after four cycles of cysplatin-based chemotherapy. Longitudinal monitoring of three patients showed that the CTCs^EMT detection is related to poor therapeutic response.

Conclusions

The RT-PCR-based approach for the evaluation of CTCs^EMT phenotype could be a promising and inexpensive tool to predict the prognosis and the therapeutic response in NSCLC patients.

Genome-wide DNA methylation analysis in jejunum of Sus scrofa with intrauterine growth restriction

Intrauterine growth restriction (IUGR) may elicit a series of postnatal body developmental and metabolic diseases due to their impaired growth and development in the mammalian embryo/fetus during pregnancy. In the present study, we hypothesized that IUGR may lead to abnormally regulated DNA methylation in the intestine, causing intestinal dysfunctions. We applied reduced representation bisulfite sequencing (RRBS) technology to study the jejunum tissues from four newborn IUGR piglets and their normal body weight (NBW) littermates. The results revealed extensively regional DNA methylation changes between IUGR/NBW pairs from different gilts, affecting dozens of genes. Hiseq-based bisulfite sequencing PCR (Hiseq-BSP) was used for validations of 19 genes with epigenetic abnormality, confirming three genes (AIFM1, MTMR1, and TWIST2) in extra samples. Furthermore, integrated analysis of these 19 genes with proteome data indicated that there were three main genes (BCAP31, IRAK1, and AIFM1) interacting with important immunity- or metabolism-related proteins, which could explain the potential intestinal dysfunctions of IUGR piglets. We conclude that IUGR can lead to disparate DNA methylation in the intestine and these changes may affect several important biological processes such as cell apoptosis, cell differentiation, and immunity, which provides more clues linking IUGR and its long-term complications.

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.

Cytoplasmic expression of Twist1, an EMT-related transcription factor, is associated with higher grades renal cell carcinomas and worse progression-free survival in clear cell renal cell carcinoma

Twist1 is a key transcription factor, which confers tumor cells with cancer stem cell (CSC)-like characteristics and enhances epithelial-mesenchymal transition in pathological conditions including tumor malignancy and metastasis. This study aimed to evaluate the expression patterns and clinical significance of Twist1 in renal cell carcinoma (RCC). The cytoplasmic and nuclear expression of Twist1 were examined in 252 well-defined renal tumor tissues, including 173 (68.7%) clear cell renal cell carcinomas (ccRCC), 45 (17.9%) papillary renal cell carcinomas (pRCC) and 34 (13.5%) chromophobe renal cell carcinoma, by immunohistochemistry on a tissue microarray. The association between expression of this marker and clinicopathologic parameters and survival outcomes were then analyzed. Twist1 was mainly localized to the cytoplasm of tumor cells (98.8%). Increased cytoplasmic expression of Twist1 was associated with higher grade tumors (P = 0.045), renal vein invasion (P = 0.031) and microvascular invasion (P = 0.044) in RCC. It was positively correlated with higher grade tumors (P = 0.026), shorter progression-free survival time (P = 0.027) in patients with ccRCC, and also with higher stage in pRCC patients (P = 0.036). Significantly higher cytoplasmic expression levels of Twist1 were found in ccRCC and pRCC subtypes, due to their more aggressive tumor behavior. Increased cytoplasmic expression of Twist1 had a critical role in worse prognosis in ccRCC. These findings suggest that cytoplasmic, rather than nuclear expression of Twist1 can be considered as a prognostic and therapeutic marker for targeted therapy of RCC, especially for ccRCC patients.

Epithelial-to-Mesenchymal Transition: Epigenetic Reprogramming Driving Cellular Plasticity

Epithelial-to-mesenchymal transition (EMT) is a process in which epithelial cells lose their junctions and polarity to gain a motile mesenchymal phenotype. EMT is essential during embryogenesis and adult physiological processes like wound healing, but is aberrantly activated in pathological conditions like fibrosis and cancer. A series of transcription factors (EMT-inducing transcription factor; EMT-TF) regulate the induction of EMT by repressing the transcription of epithelial genes while activating mesenchymal genes through mechanisms still debated. The nuclear interaction of EMT-TFs with larger protein complexes involved in epigenetic genome modulation has attracted recent attention to explain functions of EMT-TFs during reprogramming and cellular differentiation. In this review, we discuss recent advances in understanding the interplay between epigenetic regulators and EMT transcription factors and how these findings could be used to establish new therapeutic approaches to tackle EMT-related diseases.

Benzo(a)pyrene enhances the EMT-associated migration of lung adenocarcinoma A549 cells by upregulating Twist1

Benzo(a)pyrene (BaP), an important toxic component of cigarette smoke, can cause lung cancer and lead to the progression of lung cancer. In the present study, we investigated the effect of BaP on the migration of lung adenocarcinoma A549 cells. BaP (1 µM) promoted the migration of A549 cells in a time-dependent manner and upregulated the expression of the Twist family BHLH transcription factor 1 (Twist1). BaP also induced upregulation of the mesenchymal markers N-cadherin and vimentin and downregulation of the epithelial marker E-cadherin. When the expression of Twist1 was knocked down in A549 cells that were treated with BaP for 4 weeks (A549BaP-4w), the expression of Twist1 decreased, which inhibited the migration capacity of A549BaP-4w cells, the expression of N-cadherin and vimentin was downregulated and the expression of E-cadherin was upregulated. In addition, morphological observations of A549BaP-4w cells revealed that the epithelial characteristics of A549 cells became mesenchymal characteristics. When the expression of Twist1 was knocked down, the A549BaP-4w cells were transformed back to cells with epithelial characteristics. In conclusion, the results from the present study indicate that BaP enhances the epithelial-mesenchymal transition-associated migration of lung adenocarcinoma A549 cells by upregulating Twist1.

HtrA3 stromal expression is correlated with tumor budding in stage II colorectal cancer

Tumor budding is a well-established adverse prognostic factor in colorectal carcinoma (CRC). It may represent a form of epithelial-to-mesenchymal transition (EMT), although the underlying mechanisms remain unclear. High-temperature requirement A3 (HtrA3) is an inhibitor of the bone morphogenetic protein pathway, the suppression of which has been linked to EMT. Since HtrA3 is highly expressed in the desmoplastic stroma at the CRC invasive front, we sought to evaluate the relationship between tumor budding and HtrA3 expression in 172 stage II CRC resection specimens. All tumors were evaluated for tumor budding, with the highest budding slide selected for pan-keratin (CK) and HtrA3 immunohistochemistry. Representative areas of tumor core and invasive front, including budding and non-budding areas, were marked on CK stained slides, and then evaluated on HtrA3 stained slides. HtrA3 expression in tumor cells (tHtrA3) and peritumoral stroma (sHtrA3) was assessed for staining percentage and intensity (the product yielding a final score). Tumors with high-grade tumor budding (HGTB) showed increased expression of sHtrA3 in budding areas compared to non-budding areas at the invasive front (P<0.001). In addition, sHtrA3 expression at the invasive front was significantly higher in HGTB tumors compared to minimally budding tumors (P<0.05). tHtrA3 expression at the invasive front was significantly associated with high histological grade (P<0.05). Higher sHtrA3 expression in the tumor core (but not invasive front) was significantly associated with decreased 5-year overall survival on univariate analysis (P<0.05), but not multivariate analysis. HtrA3 expression in the peritumoral stroma of patients with stage II CRC is associated with HGTB and may be a novel marker of poor outcome.

High tumor budding count is associated with adverse clinicopathologic features and poor prognosis in breast carcinoma

This study is to address the significance of tumor budding (TB) in breast carcinoma. Totally 244 estrogen receptor-positive (ER+)/HER2-negative (HER2-) and 131 triple-negative breast carcinoma (TNBC) diagnosed from 2004 to 2014 were analyzed. TB (cluster of up to 5 tumor cells at the invasive front) was evaluated using five 200× high-power fields (HPF) at the hotspot. The highest TB (H-TB) in 1 HPF and average TB (A-TB) in 5 HPFs were correlated with lymph node and distant metastasis, lymphovascular invasion (LVI), local recurrence, overall survival (OS), and disease-free survival (DFS). In ER+/HER2- cancer, H-TB and A-TB were significantly associated with distant metastasis. In TNBC, H-TB was associated with distant metastasis by univariate but not multivariate analysis; H-TB and A-TB were associated with LVI and worse OS (all P < .05). TB is associated with poor prognosis in ER+/HER2- and TNBC cancer. Evaluation of H-TB may be sufficient in breast carcinoma.

Epithelial-to-mesenchymal transition transcription factors in cancer-associated fibroblasts

Beyond inducing epithelial‐to‐mesenchymal transcription (EMT), transcriptional factors of the Snail, ZEB and Twist families (EMT‐TFs) control global plasticity programmes affecting cell stemness and fate. Literature addressing the reactivation of these factors in adult tumour cells is very extensive, as they enable cancer cell plasticity and fuel both tumour initiation and metastatic spread. Incipient data reveal that EMT‐TFs are also expressed in fibroblasts, providing these with additional properties. Here, I will review recent reports on the expression of EMT‐TFs in cancer‐associated fibroblasts (CAFs). The new model suggests that EMT‐TFs can be envisioned as essential metastasis and chemoresistance‐promoting molecules, thereby enabling coordinated plasticity programmes in parenchyma and stroma–tumour compartments.

Vascular Invasion and Stromal S100A4 Expression at the Invasive Front of Colorectal Cancer are Novel Determinants and Tumor Prognostic Markers

Object: The aim of the present study was to investigate the clinicopathological characteristics and prognostic factors associated with sporadic colorectal cancer (CRC). We examined the clinicopathological findings and immunohistochemical expression of tumor prognostic markers at tumor budding sites to determine their predictive value for patient prognosis.

Materials and Methods: Immunohistochemical examination was performed by tissue microarray (TMA) of specimens from 106 patients with CRC. On hematoxylin and eosin (H&E)-stained tumor tissue slides, a representative area of tumor budding at the invasive front was selected for the construction of a TMA. Immunostaining for matrix metalloproteinase-7 (MMP7), the laminin-5 (ln-5) γ2 chain and S100A4 was performed to determine the association between patient survival and these markers.

Results: Clinicopathological variables were also assessed. Tumor location, histological type, degree of lymphatic invasion and vascular invasion, tumor stage, epithelial expression of S100A4, stromal cell expression of S100A4 and expression of the ln-5γ2 chain were associated with an increased risk of mortality. Five factors were retained in the multivariate logistic regression analysis. Specifically, the tumor location, degree of lymphatic invasion and vascular invasion, tumor stage and stromal cell expression of S100A4 remained significant predictors of patient survival after controlling for the other variables.

Conclusion: Vascular invasion and stromal expression of S100A4 in the tumor budding areas correlated with patient survival. Stromal immunostaining of S100A4 may be useful for identifying high-risk patients with advanced CRC.

Roles and epigenetic regulation of epithelial-mesenchymal transition and its transcription factors in cancer initiation and progression

The epithelial-mesenchymal transition (EMT) is a crucial developmental process by which epithelial cells undergo a mesenchymal phenotypic change. During EMT, epigenetic mechanisms including DNA methylation and histone modifications are involved in the regulation of EMT-related genes. The epigenetic gene silencing of the epithelial marker E-cadherin has been well characterized. In particular, three major transcriptional repressors of E-cadherin, Snail, ZEB, and Twist families, also known as EMT-inducing transcription factors (EMT-TFs), play a crucial role in this process by cooperating with multiple epigenetic modifiers. Furthermore, recent studies have identified the novel epigenetic modifiers that control the expression of EMT-TFs, and these modifiers have emerged as critical regulators of cancer development and as novel therapeutic targets for human cancer. In this review, the diverse functions of EMT-TFs in cancer progression, the cooperative mechanisms of EMT-TFs with epigenetic modifiers, and epigenetic regulatory roles for the expression of EMT-TFs will be discussed.

Somatic POLE proofreading domain mutation, immune response, and prognosis in colorectal cancer: a retrospective, pooled biomarker study

BACKGROUND

Precision cancer medicine depends on defining distinct tumour subgroups using biomarkers that may occur at very modest frequencies. One such subgroup comprises patients with exceptionally mutated (ultramutated) cancers caused by mutations that impair DNA polymerase epsilon (POLE) proofreading.

METHODS

We examined the association of POLE proofreading domain mutation with clinicopathological variables and immune response in colorectal cancers from clinical trials (VICTOR, QUASAR2, and PETACC-3) and colorectal cancer cohorts (Leiden University Medical Centre 1 and 2, Oslo 1 and 2, Bern, AMC-AJCC-II, and Epicolon-1). We subsequently investigated its association with prognosis in stage II/III colorectal cancer by Cox regression of pooled individual patient data from more than 4500 cases from these studies.

FINDINGS

Pathogenic somatic POLE mutations were detected in 66 (1·0%) of 6517 colorectal cancers, and were mutually exclusive with mismatch repair deficiency (MMR-D) in the 6277 cases for whom both markers were determined (none of 66 vs 833 [13·4%] of 6211; p<0·0001). Compared with cases with wild-type POLE, cases with POLE mutations were younger at diagnosis (median 54·5 years vs 67·2 years; p<0·0001), were more frequently male (50 [75·8%] of 66 vs 3577 [55·5%] of 6445; p=0·0010), more frequently had right-sided tumour location (44 [68·8%] of 64 vs 2463 [39·8%] of 6193; p<0·0001), and were diagnosed at an earlier disease stage (p=0·006, χ2 test for trend). Compared with mismatch repair proficient (MMR-P) POLE wild-type tumours, POLE-mutant colorectal cancers displayed increased CD8+ lymphocyte infiltration and expression of cytotoxic T-cell markers and effector cytokines, similar in extent to that observed in immunogenic MMR-D cancers. Both POLE mutation and MMR-D were associated with significantly reduced risk of recurrence compared with MMR-P colorectal cancers in multivariable analysis (HR 0·34 [95% CI 0·11-0·76]; p=0·0060 and 0·72 [0·60-0·87]; p=0·00035), although the difference between the groups was not significant.

INTERPRETATION

POLE proofreading domain mutations identify a subset of immunogenic colorectal cancers with excellent prognosis. This association underscores the importance of rare biomarkers in precision cancer medicine, but also raises important questions about how to identify and implement them in practice.

FUNDING

Cancer Research UK, Academy of Medical Sciences, Health Foundation, EU, ERC, NIHR, Wellcome Trust, Dutch Cancer Society, Dutch Digestive Foundation.

Genome-wide profiling of DNA methylation and gene expression in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the leading cause of cancer-related death worldwide. Previous studies have suggested that DNA methylation involved in the development of ESCC. However, the precise mechanisms underlying the regulation and maintenance of the methylome as well as their relationship with ESCC remain poorly understood. Herein, we used methylated DNA immunoprecipitation sequencing (MeDIP-Seq) and RNA-Seq to investigate whole-genome DNA methylation patterns and the genome expression profiles in ESCC samples. The results of MeDIP-Seq analyses identified differentially methylated regions (DMRs) covering almost the entire genome with sufficient depth and high resolution. The gene ontology (GO) analysis showed that the DMRs related genes belonged to several different ontological domains, such as cell cycle, adhesion, proliferation and apoptosis. The RNA-Seq analysis identified a total of 6150 differentially expressed genes (3423 up-regulated and 2727 down-regulated). The significant GO terms showed that these genes belonged to several molecular functions and biological pathways. Moreover, the bisulfite-sequencing of genes MLH1, CDH5, TWIST1 and CDX1 confirmed the methylation status identified by MeDIP-Seq. And the mRNA expression levels of MLH1, TWIST1 and CDX1 were consistent with their DNA methylation profiles. The DMR region of MLH1 was found to correlate with survival. The identification of whole-genome DNA methylation patterns and gene expression profiles in ESCC provides new insight into the carcinogenesis of ESCC and represents a promising avenue through which to investigate novel therapeutic targets.