Twist mediates an aggressive phenotype in human colorectal cancer cells

Overcoming Cancer Resistance: Strategies and Modalities for Effective Treatment

Resistance to cancer drugs is a complex phenomenon that poses a significant challenge in the treatment of various malignancies. This review comprehensively explores cancer resistance mechanisms and discusses emerging strategies and modalities to overcome this obstacle. Many factors contribute to cancer resistance, including genetic mutations, activation of alternative signaling pathways, and alterations in the tumor microenvironment. Innovative approaches, such as targeted protein degradation, immunotherapy combinations, precision medicine, and novel drug delivery systems, hold promise for improving treatment outcomes. Understanding the intricacies of cancer resistance and leveraging innovative modalities are essential for advancing cancer therapy.

Harnessing function of EMT in cancer drug resistance: a metastasis regulator determines chemotherapy response

Epithelial-mesenchymal transition (EMT) is a complicated molecular process that governs cellular shape and function changes throughout tissue development and embryogenesis. In addition, EMT contributes to the development and spread of tumors. Expanding and degrading the surrounding microenvironment, cells undergoing EMT move away from the main location. On the basis of the expression of fibroblast-specific protein-1 (FSP1), fibroblast growth factor (FGF), collagen, and smooth muscle actin (-SMA), the mesenchymal phenotype exhibited in fibroblasts is crucial for promoting EMT. While EMT is not entirely reliant on its regulators like ZEB1/2, Twist, and Snail proteins, investigation of upstream signaling (like EGF, TGF-β, Wnt) is required to get a more thorough understanding of tumor EMT. Throughout numerous cancers, connections between tumor epithelial and fibroblast cells that influence tumor growth have been found. The significance of cellular crosstalk stems from the fact that these events affect therapeutic response and disease prognosis. This study examines how classical EMT signals emanating from various cancer cells interfere to tumor metastasis, treatment resistance, and tumor recurrence.

Contribution of Autophagy to Epithelial Mesenchymal Transition Induction during Cancer Progression

Epithelial Mesenchymal Transition (EMT) is a dedifferentiation process implicated in many physio-pathological conditions including tumor transformation. EMT is regulated by several extracellular mediators and under certain conditions it can be reversible. Autophagy is a conserved catabolic process in which intracellular components such as protein/DNA aggregates and abnormal organelles are degraded in specific lysosomes. In cancer, autophagy plays a controversial role, acting in different conditions as both a tumor suppressor and a tumor-promoting mechanism. Experimental evidence shows that deep interrelations exist between EMT and autophagy-related pathways. Although this interplay has already been analyzed in previous studies, understanding mechanisms and the translational implications of autophagy/EMT need further study. The role of autophagy in EMT is not limited to morphological changes, but activation of autophagy could be important to DNA repair/damage system, cell adhesion molecules, and cell proliferation and differentiation processes. Based on this, both autophagy and EMT and related pathways are now considered as targets for cancer therapy. In this review article, the contribution of autophagy to EMT and progression of cancer is discussed. This article also describes the multiple connections between EMT and autophagy and their implication in cancer treatment.

The post-chemotherapy changes of tumor physical microenvironment: Targeting extracellular matrix to address chemoresistance

The tumor physical microenvironment (TPME) contributes to cancer chemoresistance in both mechanical and mechanobiological approaches. Along with chemotherapy, the tumor microenvironment undergoes dramatic changes, most of which can regulate TPME through extracellular matrix (ECM) remodeling and related signaling pathways. However, there is still no discussion about the post-chemotherapy TPME changes mediated by ECM remodeling, and consequent impact on chemoresistance. Herein, we summarize the TPME alterations induced by chemotherapy and corresponding influence on chemotherapy response of cancer cells in context of ECM. The response of cancer cell to chemotherapy, imposed by post-chemotherapy ECM, are discussed in both mechanical (ECM physical features) and mechanobiological (ECM-responsive signaling pathways) manner. In the end, we present ECM remodeling and related signaling pathways as two promising clinic strategies to relieve or overcome chemoresistance induced by TPME change, and summarize the corresponding therapeutic agents currently being tested in clinical trials.

Zinc finger proteins and ATP-binding cassette transporter-dependent multidrug resistance

BACKGROUND

Multidrug resistance (MDR) remains a significant challenge in cancer treatment, leading to poor clinical outcomes. Dysregulation of ATP-binding cassette (ABC) transporters has been identified as a key contributor to MDR. Zinc finger proteins (ZNPs) are key regulators of transcription and have emerged as potential contributors to cancer drug resistance. Bridging the knowledge gap between ZNPs and MDR is essential to understand a source of heterogeneity in cancer treatment. This review sought to elucidate how different ZNPs modulate the transcriptional regulation of ABC genes, contributing to resistance to cancer therapies.

METHODS

The search was conducted using PubMed, Google Scholar, EMBASE and Web of Science.

RESULTS

In addition to ABC-blockers, the transcriptional features regulated by ZNP are expected to play a role in reversing ABC-mediated MDR and predicting the efficacy of anticancer treatments. Among the ZNP-induced epithelial to mesenchymal transition, SNAIL, SLUG and Zebs have been identified as important factors in promoting MDR through activation of ATM, NFκB and PI3K/Akt pathways, exposing the metabolism to potential ZNP-MDR interactions. Additionally, nuclear receptors, such as VDR, ER and PXR have been found to modulate certain ABC regulations. Other C2H2-type zinc fingers, including Kruppel-like factors, Gli and Sp also have the potential to contribute to MDR.

CONCLUSION

Besides reviewing evidence on the effects of ZNP dysregulation on ABC-related chemoresistance in malignancies, significant markers of ZNP functions are discussed to highlight the clinical implications of gene-to-gene and microenvironment-to-gene interactions on MDR prospects. Future research on ZNP-derived biomarkers is crucial for addressing heterogeneity in cancer therapy.

The Promoting Role of HK II in Tumor Development and the Research Progress of Its Inhibitors

Increased glycolysis is a key characteristic of malignant cells that contributes to their high proliferation rates and ability to develop drug resistance. The glycolysis rate-limiting enzyme hexokinase II (HK II) is overexpressed in most tumor cells and significantly affects tumor development. This paper examines the structure of HK II and the specific biological factors that influence its role in tumor development, as well as the potential of HK II inhibitors in antitumor therapy. Furthermore, we identify and discuss the inhibitors of HK II that have been reported in the literature.

Single-cell causal network inferred by cross-mapping entropy

Gene regulatory networks (GRNs) reveal the complex molecular interactions that govern cell state. However, it is challenging for identifying causal relations among genes due to noisy data and molecular nonlinearity. Here, we propose a novel causal criterion, neighbor cross-mapping entropy (NME), for inferring GRNs from both steady data and time-series data. NME is designed to quantify 'continuous causality' or functional dependency from one variable to another based on their function continuity with varying neighbor sizes. NME shows superior performance on benchmark datasets, comparing with existing methods. By applying to scRNA-seq datasets, NME not only reliably inferred GRNs for cell types but also identified cell states. Based on the inferred GRNs and further their activity matrices, NME showed better performance in single-cell clustering and downstream analyses. In summary, based on continuous causality, NME provides a powerful tool in inferring causal regulations of GRNs between genes from scRNA-seq data, which is further exploited to identify novel cell types/states and predict cell type-specific network modules.

TRPM7 transactivates the FOSL1 gene through STAT3 and enhances glioma stemness

INTRODUCTION

We previously reported that TRPM7 regulates glioma cells' stemness through STAT3. In addition, we demonstrated that FOSL1 is a response gene for TRPM7, and the FOSL1 gene serves as an oncogene to promote glioma proliferation and invasion.

METHODS

In the present study, we determined the effects of FOSL1 on glioma stem cell (GSC) markers CD133 and ALDH1 by flow cytometry, and the maintenance of stem cell activity by extreme limiting dilution assays (ELDA). To further gain insight into the mechanism by which TRPM7 activates transcription of the FOSL1 gene to contribute to glioma stemness, we constructed a FOSL1 promoter and its GAS mutants followed by luciferase reporter assays and ChIP-qPCR in a glioma cell line and glioma patient-derived xenoline. We further examined GSC markers ALDH1 and TRPM7 as well as FOSL1 by immunohistochemistry staining (IHC) in brain tissue microarray (TMA) of glioma patients.

RESULTS

We revealed that FOSL1 knockdown reduces the expression of GSC markers CD133 and ALDH1, and FOSL1 is required to maintain stem cell activity in glioma cells. The experiments also showed that mutations of - 328 to - 336 and - 378 to - 386 GAS elements markedly reduced FOSL1 promoter activity. Constitutively active STAT3 increased while dominant-negative STAT3 decreased FOSL1 promoter activity. Furthermore, overexpression of TRPM7 enhanced while silencing of TRPM7 reduced FOSL1 promoter activity. ChIP-qPCR assays revealed that STAT3, present in nuclear lysates of glioma cells stimulated by constitutively activated STAT3, can bind to two GAS elements, respectively. We demonstrated that deacetylation of FOSL1 at the Lys-116 residue located within its DNA binding domain led to an increase in FOSL1 transcriptional activity. We found that the expression of TRPM7, ALDH1, and FOSL1 protein is associated with grades of malignant glioma, and TRPM7 protein expression correlates to the expression of ALDH1 and FOSL1 in glioma patients.

CONCLUSIONS

These combined results demonstrated that TRPM7 induced FOSL1 transcriptional activation, which is mediated by the action of STAT3, a mechanism shown to be important in glioma stemness. These results indicated that FOSL1, similar to GSC markers ALDH1 and TRPM7, is a diagnostic marker and potential drug target for glioma patients.

ABCB1 and ABCC1 Function during TGF-β-Induced Epithelial-Mesenchymal Transition: Relationship between Multidrug Resistance and Tumor Progression

Multidrug resistance (MDR) and induction of metastasis are some of the puzzles encountered during cancer chemotherapy. The MDR phenotype is associated with overexpression of ABC transporters, involved in drug efflux. Metastasis originates from the epithelial-mesenchymal transition (EMT), in which cells acquire a migratory phenotype, invading new tissues. ABC transporters' role during EMT is still elusive, though cells undergoing EMT exhibit enhanced ABCB1 expression. We demonstrated increased ABCB1 expression but no change in activity after TGF-β-induced EMT in A549 cells. Moreover, ABCB1 inhibition by verapamil increased snail and fibronectin expression, an event associated with upregulation of ABCB1, evidencing coincident cell signaling pathways leading to ABCB1 and EMT-related markers transcription, rather than a direct effect of transport. Additionally, for the first time, increased ABCC1 expression and activity was observed after EMT, and use of ABCC1 inhibitors partially inhibited EMT-marker snail, although increased ABCC1 function translated into collateral sensibility to daunorubicin. More investigations must be done to evaluate the real benefits that the gain of ABC transporters might have on the process of metastasis. Considering ABCC1 is involved in the stress response, affecting intracellular GSH content and drug detoxification, this transporter could be used as a therapeutic target in cancer cells undergoing EMT.

Relationship between Epithelial-to-Mesenchymal Transition and Tumor-Associated Macrophages in Colorectal Liver Metastases

The liver is the most common metastatic site in colorectal cancer (CRC) patients. Indeed, 25-30% of the cases develop colorectal liver metastasis (CLM), showing an extremely poor 5-year survival rate and resistance to conventional anticancer therapies. Tumor-associated macrophages (TAMs) provide a nurturing microenvironment for CRC metastasis, promoting epithelial-to-mesenchymal transition (EMT) through the TGF-β signaling pathway, thus driving tumor cells to acquire mesenchymal properties that allow them to migrate from the primary tumor and invade the new metastatic site. EMT is known to contribute to the disruption of blood vessel integrity and the generation of circulating tumor cells (CTCs), thus being closely related to high metastatic potential in numerous solid cancers. Despite the fact that it is well-recognized that the crosstalk between tumor cells and the inflammatory microenvironment is crucial in the EMT process, the association between the EMT and the role of TAMs is still poorly understood. In this review, we elaborated on the role that TAMs exert in the induction of EMT during CLM development. Since TAMs are the major source of TGF-β in the liver, we also focused on novel insights into their role in TGF-β-induced EMT.

Chemotherapy as a regulator of extracellular matrix-cell communication: Implications in therapy resistance

The development of most solid cancers, including pancreatic, breast, lung, liver, and ovarian cancer, involves a desmoplastic reaction: a process of major remodeling of the extracellular matrix (ECM) affecting the ECM composition, mechanics, and microarchitecture. These properties of the ECM influence key cancer cell functions, including treatment resistance. Furthermore, emerging data show that various chemotherapeutic treatments lead to alterations in ECM features and ECM-cell communication. Here, we summarize the current knowledge around the effects of chemotherapy on both the ECM remodeling and ECM-cell signaling and discuss the implications of these alterations on distinct mechanisms of chemoresistance. Additionally, we provide an overview of current therapeutic strategies and ongoing clinical trials utilizing anti-cancer drugs to target the ECM-cell communication and explore the future challenges of these strategies.

Crosstalk between Ca2+ Signaling and Cancer Stemness: The Link to Cisplatin Resistance

In the fight against cancer, therapeutic strategies using cisplatin are severely limited by the appearance of a resistant phenotype. While cisplatin is usually efficient at the beginning of the treatment, several patients endure resistance to this agent and face relapse. One of the reasons for this resistant phenotype is the emergence of a cell subpopulation known as cancer stem cells (CSCs). Due to their quiescent phenotype and self-renewal abilities, these cells have recently been recognized as a crucial field of investigation in cancer and treatment resistance. Changes in intracellular calcium (Ca²⁺) through Ca²⁺ channel activity are essential for many cellular processes such as proliferation, migration, differentiation, and survival in various cell types. It is now proved that altered Ca²⁺ signaling is a hallmark of cancer, and several Ca²⁺ channels have been linked to CSC functions and therapy resistance. Moreover, cisplatin was shown to interfere with Ca²⁺ homeostasis; thus, it is considered likely that cisplatin-induced aberrant Ca²⁺ signaling is linked to CSCs biology and, therefore, therapy failure. The molecular signature defining the resistant phenotype varies between tumors, and the number of resistance mechanisms activated in response to a range of pressures dictates the global degree of cisplatin resistance. However, if we can understand the molecular mechanisms linking Ca²⁺ to cisplatin-induced resistance and CSC behaviors, alternative and novel therapeutic strategies could be considered. In this review, we examine how cisplatin interferes with Ca²⁺ homeostasis in tumor cells. We also summarize how cisplatin induces CSC markers in cancer. Finally, we highlight the role of Ca²⁺ in cancer stemness and focus on how they are involved in cisplatin-induced resistance through the increase of cancer stem cell populations and via specific pathways.

Piceatannol Prevents Colon Cancer Progression via Dual-Targeting to M2-Polarized Tumor-Associated Macrophages and the TGF-β1 Positive Feedback Signaling Pathway

SCOPE

M2 phenotype tumor-associated macrophages (M2-TAMs) play a key role in distant metastasis and poor clinical outcomes. Herein, a specific molecular mechanism that contributes to malignant progression is illuminated and investigates whether piceatannol (PIC) can target the crosstalk between M2-TAMs and cancer cells for potential colorectal cancer (CRC) therapy.

METHODS AND RESULTS

To mimic the tumor microenvironment (TME), direct and indirect coculture systems in vitro and in vivo mouse xenograft models are established. The results demonstrate that post-treatment with PIC in TME more effectively prevented the aggressive features and stemness of SW480 cells by restricting the polarization of M2-like macrophages and blocking the transforming growth factor β1 (TGF-β1) positive feedback autocrine/paracrine loop that exists between M2-like polarized macrophages and cancer cells. Furthermore, xenograft assays also observe significant repression in tumor growth and lung metastases with the administration of PIC. The key mechanism underlying the antimetastasis effects of PIC may include its directly inhibitory activity against TGF-β receptor type-1 (TGF-βR1) in the M2-like TAMs-created TME.

CONCLUSION

These novel findings demonstrate that PIC is a potent TGF-β1/TGF-βR1 pathway inhibitor and TME modulator for preventing tumor progression and metastasis in CRC by reeducating TAMs.

AMP- activated protein kinase (AMPK) promotes breast cancer stemness and drug resistance

Breast cancer stem cells (BCSCs) are a major cause of therapy resistance and tumour progression. Currently, their regulation is not entirely understood. Previous work from our laboratory demonstrated a context-specific pro-tumorigenic role for AMP-activated protein kinase (AMPK) under anchorage-deprivation and mammosphere formation, which are hallmarks of BCSCs. Therefore, we investigated the role of AMPK in the maintenance of BCSC state/function. AMPK depletion reduces serial sphere formation in vitro and tumour initiation in vivo. Intriguingly, tumour-derived cell analysis using stem cell markers and functional assays revealed that AMPK is required for the maintenance of BCSC populations in vivo. AMPK promotes the expression of stemness genes such as NANOG, SOX2 and BMI1 through the transcriptional upregulation of TWIST via promoter acetylation. Further, AMPK-driven stemness plays a critical role in doxorubicin resistance. Significantly, AMPK activity increased after chemotherapy in patient-derived tumour samples alongside an increase in stemness markers. Importantly, AMPK depletion sensitises mouse tumours to doxorubicin treatment. Our work indicates that targeting of AMPK in conjunction with regular chemotherapy is likely to reduce the stem cell pool and improve chemosensitivity in breast cancers.

Summary: AMPK inhibition in conjunction with regular chemotherapy is likely to reduce the stem cell pool and improve chemosensitivity and therapeutic outcomes in breast cancers.

Dehydroevodiamine inhibits lung metastasis by suppressing survival and metastatic abilities of colorectal cancer cells

BACKGROUND

Despite the rising 5-year survival rate of colorectal cancer (CRC) patients, the survival rate decreases as the stage progress, and a low survival rate is highly associated with metastasis.

PURPOSE

The purpose of our study is to investigate the effect of dehydroevodiamine (DHE) on the lung metastasis of CRC and the proliferation of CRC cells.

STUDY DESIGN

Cell death was confirmed after DHE treatment on several CRC cell lines. The mechanism of cell cytotoxicity was found using flow cytometry. After that, the expression of the proteins or mRNAs related to the cell cytotoxicity was confirmed. Also, anti-metastatic ability of DHE in CRC cells was measured by checking the expression of Epithelial to Mesenchymal Transition (EMT) markers. Lung metastasis mouse model was established, and DHE was administered orally for 14 days.

RESULTS

DHE suppressed the viability of HCT116, CT26, SW480, and LoVo cells. DHE treatment led to G2/M arrest via a reduction of cyclin B1/CDK1 and caspase-dependent apoptosis. It also induced autophagy by regulating LC3-II and beclin-1 expression. Additionally, migration and invasion of CRC cells were decreased by DHE through regulation of the expression of EMT markers. Oral administration of DHE could inhibit the lung metastasis of CT26 cells in an in vivo model.

CONCLUSION

Our study demonstrated that DHE has a potential therapeutic effect on colorectal cancer metastasis.

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).

Recent Updates on Mechanisms of Resistance to 5-Fluorouracil and Reversal Strategies in Colon Cancer Treatment

5-Fluorouracil (5-FU) plus leucovorin (LV) remain as the mainstay standard adjuvant chemotherapy treatment for early stage colon cancer, and the preferred first-line option for metastatic colon cancer patients in combination with oxaliplatin in FOLFOX, or irinotecan in FOLFIRI regimens. Despite treatment success to a certain extent, the incidence of chemotherapy failure attributed to chemotherapy resistance is still reported in many patients. This resistance, which can be defined by tumor tolerance against chemotherapy, either intrinsic or acquired, is primarily driven by the dysregulation of various components in distinct pathways. In recent years, it has been established that the incidence of 5-FU resistance, akin to multidrug resistance, can be attributed to the alterations in drug transport, evasion of apoptosis, changes in the cell cycle and DNA-damage repair machinery, regulation of autophagy, epithelial-to-mesenchymal transition, cancer stem cell involvement, tumor microenvironment interactions, miRNA dysregulations, epigenetic alterations, as well as redox imbalances. Certain resistance mechanisms that are 5-FU-specific have also been ascertained to include the upregulation of thymidylate synthase, dihydropyrimidine dehydrogenase, methylenetetrahydrofolate reductase, and the downregulation of thymidine phosphorylase. Indeed, the successful modulation of these mechanisms have been the game plan of numerous studies that had employed small molecule inhibitors, plant-based small molecules, and non-coding RNA regulators to effectively reverse 5-FU resistance in colon cancer cells. It is hoped that these studies would provide fundamental knowledge to further our understanding prior developing novel drugs in the near future that would synergistically work with 5-FU to potentiate its antitumor effects and improve the patient's overall survival.

Targeting hexokinase 2 increases the sensitivity of oxaliplatin by Twist1 in colorectal cancer

Colorectal cancer (CRC) is the third most malignant tumour worldwide, with high mortality and recurrence. Chemoresistance is one of the main factors leading to metastasis and poor prognosis in advanced CRC patients. By analysing the Gene Expression Omnibus data set, we found higher hexokinase 2 (HK2) expression levels in patients with metastatic CRC than in those with primary CRC. Moreover, we observed higher enrichment in oxaliplatin resistance‐related gene sets in metastatic CRC than in primary CRC. However, the underlying relationship has not yet been elucidated. In our study, HK2 expression was significantly elevated in CRC patients. Gene set enrichment analysis (GSEA) revealed multi‐drug resistance and epithelial‐mesenchymal transition (EMT) pathways related to high HK2 expression. Our results showed that knockdown of HK2 significantly inhibited vimentin and Twist1 expression and promoted TJP1 and E‐cadherin expression in CRC cells. Additionally, transcriptional and enzymatic inhibition of HK2 by 3‐bromopyruvate (3‐bp) impaired oxaliplatin resistance in vitro and in vivo. Mechanistically, HK2 interacts with and stabilized Twist1 by preventing its ubiquitin‐mediated degradation, which is related to oxaliplatin resistance, in CRC cells. Overexpression of Twist1 reduced the apoptosis rate by HK2 knockdown in CRC cells. Collectively, we discovered that HK2 is a crucial regulator that mediates oxaliplatin resistance through Twist1. These findings identify HK2 and Twist1 as promising drug targets for CRC chemoresistance.

BMAL1 Knockdown Leans Epithelial-Mesenchymal Balance toward Epithelial Properties and Decreases the Chemoresistance of Colon Carcinoma Cells

The circadian clock coordinates biological and physiological functions to day/night cycles. The perturbation of the circadian clock increases cancer risk and affects cancer progression. Here, we studied how BMAL1 knockdown (BMAL1-KD) by shRNA affects the epithelial-mesenchymal transition (EMT), a critical early event in the invasion and metastasis of colorectal carcinoma (CRC). In corresponding to a gene set enrichment analysis, which showed a significant enrichment of EMT and invasive signatures in BMAL1_high CRC patients as compared to BMAL1_low CRC patients, our results revealed that BMAL1 is implicated in keeping the epithelial-mesenchymal equilibrium of CRC cells and influences their capacity of adhesion, migration, invasion, and chemoresistance. Firstly, BMAL1-KD increased the expression of epithelial markers (E-cadherin, CK-20, and EpCAM) but decreased the expression of Twist and mesenchymal markers (N-cadherin and vimentin) in CRC cell lines. Finally, the molecular alterations after BMAL1-KD promoted mesenchymal-to-epithelial transition-like changes mostly appeared in two primary CRC cell lines (i.e., HCT116 and SW480) compared to the metastatic cell line SW620. As a consequence, migration/invasion and drug resistance capacities decreased in HCT116 and SW480 BMAL1-KD cells. Together, BMAL1-KD alerts the delicate equilibrium between epithelial and mesenchymal properties of CRC cell lines, which revealed the crucial role of BMAL1 in EMT-related CRC metastasis and chemoresistance.

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.

Advances in Modeling the Immune Microenvironment of Colorectal Cancer

Colorectal cancer (CRC) is the third most common cancer and second leading cause of cancer-related death in the US. CRC frequently metastasizes to the liver and these patients have a particularly poor prognosis. The infiltration of immune cells into CRC tumors and liver metastases accurately predicts disease progression and patient survival. Despite the evident influence of immune cells in the CRC tumor microenvironment (TME), efforts to identify immunotherapies for CRC patients have been limited. Here, we argue that preclinical model systems that recapitulate key features of the tumor microenvironment-including tumor, stromal, and immune cells; the extracellular matrix; and the vasculature-are crucial for studies of immunity in the CRC TME and the utility of immunotherapies for CRC patients. We briefly review the discoveries, advantages, and disadvantages of current in vitro and in vivo model systems, including 2D cell culture models, 3D culture systems, murine models, and organ-on-a-chip technologies.

FOLFOX Therapy Induces Feedback Upregulation of CD44v6 through YB-1 to Maintain Stemness in Colon Initiating Cells

Cancer initiating cells (CICs) drive tumor formation and drug-resistance, but how they develop drug-resistance characteristics is not well understood. In this study, we demonstrate that chemotherapeutic agent FOLFOX, commonly used for drug-resistant/metastatic colorectal cancer (CRC) treatment, induces overexpression of CD44v6, MDR1, and oncogenic transcription/translation factor Y-box-binding protein-1 (YB-1). Our study revealed that CD44v6, a receptor for hyaluronan, increased the YB-1 expression through PGE2/EP1-mTOR pathway. Deleting CD44v6, and YB-1 by the CRISPR/Cas9 system attenuates the in vitro and in vivo tumor growth of CICs from FOLFOX resistant cells. The results of DNA:CD44v6 immunoprecipitated complexes by ChIP (chromatin-immunoprecipitation) assay showed that CD44v6 maintained the stemness traits by promoting several antiapoptotic and stemness genes, including cyclin-D1,BCL2,FZD1,GINS-1, and MMP9. Further, computer-based analysis of the clones obtained from the DNA:CD44v6 complex revealed the presence of various consensus binding sites for core stemness-associated transcription factors “CTOS” (c-Myc, TWIST1, OCT4, and SOX2). Simultaneous expressions of CD44v6 and CTOS in CD44v6 knockout CICs reverted differentiated CD44v6-knockout CICs into CICs. Finally, this study for the first time describes a positive feedback loop that couples YB-1 induction and CD44 alternative splicing to sustain the MDR1 and CD44v6 expressions, and CD44v6 is required for the reversion of differentiated tumor cells into CICs.

Y-Box Binding Protein-1 Promotes Epithelial-Mesenchymal Transition in Sorafenib-Resistant Hepatocellular Carcinoma Cells

Hepatocellular carcinoma is one of the most common cancer types worldwide. In cases of advanced-stage disease, sorafenib is considered the treatment of choice. However, resistance to sorafenib remains a major obstacle for effective clinical application. Based on integrated phosphoproteomic and The Cancer Genome Atlas (TCGA) data, we identified a transcription factor, Y-box binding protein-1 (YB-1), with elevated phosphorylation of Ser102 in sorafenib-resistant HuH-7^R cells. Phosphoinositide-3-kinase (PI3K) and protein kinase B (AKT) were activated by sorafenib, which, in turn, increased the phosphorylation level of YB-1. In functional analyses, knockdown of YB-1 led to decreased cell migration and invasion in vitro. At the molecular level, inhibition of YB-1 induced suppression of zinc-finger protein SNAI1 (Snail), twist-related protein 1 (Twist1), zinc-finger E-box-binding homeobox 1 (Zeb1), matrix metalloproteinase-2 (MMP-2) and vimentin levels, implying a role of YB-1 in the epithelial-mesenchymal transition (EMT) process in HuH-7^R cells. Additionally, YB-1 contributes to morphological alterations resulting from F-actin rearrangement through Cdc42 activation. Mutation analyses revealed that phosphorylation at S102 affects the migratory and invasive potential of HuH-7^R cells. Our collective findings suggest that sorafenib promotes YB-1 phosphorylation through effect from the EGFR/PI3K/AKT pathway, leading to significant enhancement of hepatocellular carcinoma (HCC) cell metastasis. Elucidation of the specific mechanisms of action of YB-1 may aid in the development of effective strategies to suppress metastasis and overcome resistance.

Role of STAT3 signaling transduction pathways in cancer stem cell-associated chemoresistance

Chemoresistance resulting from cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) results in inconsistent chemotherapeutic efficacy. The co-existence of CSCs and the EMT allows cancer cells to interconvert between differentiated and stem-like states, a phenomenon known as cellular plasticity. Phosphorylated signal transducer and activator of transcription 3 (pSTAT3) has been increasingly identified as a major contributor to CSCs and the EMT, as evidenced from preclinical studies that reversed chemoresistance through STAT3 pathway inhibition. In this review, we discuss mechanisms that center on STAT3 and its target genes responsible for regulating the EMT. We also highlight the current status of clinical trials using STAT3 pathway inhibitors.

Establishment of Acquired Cisplatin Resistance in Ovarian Cancer Cell Lines Characterized by Enriched Metastatic Properties with Increased Twist Expression

Ovarian cancer (OC) is the most lethal of the gynecologic cancers, and platinum-based treatment is a part of the standard first-line chemotherapy regimen. However, rapid development of acquired cisplatin resistance remains the main cause of treatment failure, and the underlying mechanism of resistance in OC treatment remains poorly understood. Faced with this problem, our aim in this study was to generate cisplatin-resistant (CisR) OC cell models in vitro and investigate the role of epithelial–mesenchymal transition (EMT) transcription factor Twist on acquired cisplatin resistance in OC cell models. To achieve this aim, OC cell lines OV-90 and SKOV-3 were exposed to cisplatin using pulse dosing and stepwise dose escalation methods for a duration of eight months, and a total of four CisR sublines were generated, two for each cell line. The acquired cisplatin resistance was confirmed by determination of 50% inhibitory concentration (IC₅₀) and clonogenic survival assay. Furthermore, the CisR cells were studied to assess their respective characteristics of metastasis, EMT phenotype, DNA repair and endoplasmic reticulum stress-mediated cell death. We found the IC₅₀ of CisR cells to cisplatin was 3–5 times higher than parental cells. The expression of Twist and metastatic ability of CisR cells were significantly greater than those of sensitive cells. The CisR cells displayed an EMT phenotype with decreased epithelial cell marker E-cadherin and increased mesenchymal proteins N-cadherin and vimentin. We observed that CisR cells showed significantly higher expression of DNA repair proteins, X-ray repair cross-complementing protein 1 (XRCC1) and poly (ADP-ribose) polymerases 1 (PARP1), with significantly reduced endoplasmic reticulum (ER) stress-mediated cell death. Moreover, Twist knockdown reduced metastatic ability of CisR cells by suppressing EMT, DNA repair and inducing ER stress-induced cell death. In conclusion, we highlighted the utilization of an acquired cisplatin resistance model to identify the potential role of Twist as a therapeutic target to reverse acquired cisplatin resistance in OC.

Tumor microenvironment and epithelial mesenchymal transition as targets to overcome tumor multidrug resistance

It is well established that multifactorial drug resistance hinders successful cancer treatment. Tumor cell interactions with the tumor microenvironment (TME) are crucial in epithelial-mesenchymal transition (EMT) and multidrug resistance (MDR). TME-induced factors secreted by cancer cells and cancer-associated fibroblasts (CAFs) create an inflammatory microenvironment by recruiting immune cells. CD11b+/Gr-1+ myeloid-derived suppressor cells (MDSCs) and inflammatory tumor associated macrophages (TAMs) are main immune cell types which further enhance chronic inflammation. Chronic inflammation nurtures tumor-initiating/cancer stem-like cells (CSCs), induces both EMT and MDR leading to tumor relapses. Pro-thrombotic microenvironment created by inflammatory cytokines and chemokines from TAMs, MDSCs and CAFs is also involved in EMT and MDR. MDSCs are the most common mediators of immunosuppression and are also involved in resistance to targeted therapies, e.g. BRAF inhibitors and oncolytic viruses-based therapies. Expansion of both cancer and stroma cells causes hypoxia by hypoxia-inducible transcription factors (e.g. HIF-1α) resulting in drug resistance. TME factors induce the expression of transcriptional EMT factors, MDR and metabolic adaptation of cancer cells. Promoters of several ATP-binding cassette (ABC) transporter genes contain binding sites for canonical EMT transcription factors, e.g. ZEB, TWIST and SNAIL. Changes in glycolysis, oxidative phosphorylation and autophagy during EMT also promote MDR. Conclusively, EMT signaling simultaneously increases MDR. Owing to the multifactorial nature of MDR, targeting one mechanism seems to be non-sufficient to overcome resistance. Targeting inflammatory processes by immune modulatory compounds such as mTOR inhibitors, demethylating agents, low-dosed histone deacetylase inhibitors may decrease MDR. Targeting EMT and metabolic adaptation by small molecular inhibitors might also reverse MDR. In this review, we summarize evidence for TME components as causative factors of EMT and anticancer drug resistance.

The importance of epithelial-mesenchymal transition and autophagy in cancer drug resistance

Epithelial-mesenchymal transition (EMT) and autophagy are both known to play an important role in the development of cancer. Subsequently, these processes are now being utilised as targets for therapy. Cancer is globally one of the leading causes of death, and despite many advances in treatment options, patients still face many challenges. Drug-resistance in cancer-therapy is a large problem, and both EMT and autophagy have been shown to contribute. However, given the context-dependent role of these processes and the complexity of the interactions between them, elucidating how they both act alone and interact together is important. In this review, we will provide an insight into the current landscape of the interactions of autophagy and EMT in the context of malignancy, and how this ultimately may affect drug-resistance in cancer-therapy.

Regulation of ATP-binding cassette subfamily B member 1 by Snail contributes to chemoresistance in colorectal cancer

Although accumulating evidence has indicated the intimate association between epithelial‐mesenchymal transition (EMT) and acquired resistance to chemotherapy for colorectal cancer (CRC), the underlying mechanisms remain elusive. Herein, we reported that Snail, a crucial EMT controller, was upregulated in CRC tissues. Colorectal cancer cells overexpressing Snail were found to be more resistant to 5‐fluorouracil (5‐Fu). Mechanistic studies reveal that Snail could increase the expression of ATP‐binding cassette subfamily B member 1 (ABCB1) rather than the other 23 chemoresistance‐related genes. Additionally, knockdown of ABCB1 significantly attenuated Snail‐induced 5‐Fu resistance in CRC cells. Oxaliplatin increased Snail and ABCB1 expression in CRC cells. Snail and ABCB1 were upregulated in 5‐Fu‐resistant HCT‐8 (HCT‐8/5‐Fu) cells and inhibition of Snail decreased ABCB1 in HCT‐8/5‐Fu cells. These results confirm the vital role played by ABCB1 in Snail‐induced chemoresistance. Further investigation into the relevant molecular mechanism revealed Snail‐mediated ABCB1 upregulation was independent of β‐catenin, STAT3, PXR, CAR and Foxo3a, which are commonly involved in modulating ABCB1 transcription. Instead, Snail upregulated ABCB1 transcription by directly binding to its promoter. Clinical analysis confirms that increased Snail expression correlated significantly with tumor size (P = .018), lymph node metastasis (P = .033), distant metastasis (P = .025), clinical stage grade (P = .024), and poor prognosis (P = .045) of CRC patients. Moreover, coexpression of Snail and ABCB1 was observed in CRC patients. Our study revealed that direct regulation of ABCB1 by Snail was critical for conferring chemoresistance in CRC cells. These findings unraveled the mechanisms underlying the association between EMT and chemoresistance, and provided potential targets for CRC clinical treatment.

Drug resistance and combating drug resistance in cancer

Cancer is the second leading cause of death in the US. Current major treatments for cancer management include surgery, cytotoxic chemotherapy, targeted therapy, radiation therapy, endocrine therapy and immunotherapy. Despite the endeavors and achievements made in treating cancers during the past decades, resistance to classical chemotherapeutic agents and/or novel targeted drugs continues to be a major problem in cancer therapies. Drug resistance, either existing before treatment (intrinsic) or generated after therapy (acquired), is responsible for most relapses of cancer, one of the major causes of death of the disease. Heterogeneity among patients and tumors, and the versatility of cancer to circumvent therapies make drug resistance more challenging to deal with. Better understanding the mechanisms of drug resistance is required to provide guidance to future cancer treatment and achieve better outcomes. In this review, intrinsic and acquired resistance will be discussed. In addition, new discoveries in mechanisms of drug resistance will be reviewed. Particularly, we will highlight roles of ATP in drug resistance by discussing recent findings of exceptionally high levels of intratumoral extracellular ATP as well as intracellular ATP internalized from extracellular environment. The complexity of drug resistance development suggests that combinational and personalized therapies, which should take ATP into consideration, might provide better strategies and improved efficacy for fighting drug resistance in cancer.

Inhibition of USP2 eliminates cancer stem cells and enhances TNBC responsiveness to chemotherapy

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer that harbors enriched cancer stem cell (CSC) populations in tumors. Conventional chemotherapy is a standard treatment for TNBC, but it spares the CSC populations, which cause tumor recurrence and progression. Therefore, identification of the core molecular pathway that controls CSC activity and expansion is essential for developing effective therapeutics for TNBC. In this study, we identify that USP2 deubiquitinating enzyme is upregulated in CSCs and is a novel regulator of CSCs. Genetic and pharmacological targeting of USP2 substantially inhibits the self-renewal, expansion and chemoresistance of CSCs. We show that USP2 maintains the CSC population by activating self-renewing factor Bmi1 and epithelial-mesenchymal transition through Twist upregulation. Mechanistically, USP2 promotes Twist stabilization by removing β-TrCP-mediated ubiquitination of Twist. Animal studies indicate that pharmacological inhibition of USP2 suppresses tumor progression and sensitizes tumor responses to chemotherapy in TNBC. Furthermore, the histological analyses reveal a positive correlation between USP2 upregulation and lymph node metastasis. Our findings together demonstrate a previously unrecognized role of USP2 in mediating Twist activation and CSC enrichment, suggesting that targeting USP2 is a novel therapeutic strategy to tackle TNBC.

Advances in Studies of P-Glycoprotein and Its Expression Regulators

This review deals with recent advances in studies on P-glycoprotein (P-gp) and its expression regulators, focusing especially on our own research. Firstly, we describe findings demonstrating that the distribution of P-gp along the small intestine is heterogeneous, which explains why orally administered P-gp substrate drugs often show bimodal changes of plasma concentration. Secondly, we discuss the post-translational regulation of P-gp localization and function by the scaffold proteins ezrin, radixin and moesin (ERM proteins), together with recent reports indicating that tissue-specific differences in regulation by ERM proteins in normal tissues might be retained in corresponding cancerous tissues. Thirdly, we review evidence that P-gp activity is enhanced in the process of epithelial-to-mesenchymal transition (EMT), which is associated with cancer progression, without any increase in expression of P-gp mRNA. Finally, we describe two examples in which P-gp critically influences the brain distribution of drugs, i.e., oseltamivir, where low levels of P-gp associated with early development allow oseltamivir to enter the brain, potentially resulting in neuropsychiatric side effects in children, and cilnidipine, where impairment of P-gp function in ischemia allows cilnidipine to enter the ischemic brain, where it exerts a neuroprotective action.

The Human Cytomegalovirus, from Oncomodulation to Oncogenesis

Besides its well-described impact in immunosuppressed patients, the role of human cytomegalovirus (HCMV) in the pathogenesis of cancer has been more recently investigated. In cancer, HCMV could favor the progression and the spread of the tumor, a paradigm named oncomodulation. Although oncomodulation could account for part of the protumoral effect of HCMV, it might not explain the whole impact of HCMV infection on the tumor and the tumoral microenvironment. On the contrary cases have been reported where HCMV infection slows down the progression and the spread of the tumor. In addition, HCMV proteins have oncogenic properties per se, HCMV activates pro-oncogenic pathways in infected cells, and recently the direct transformation of cells following HCMV infection has been described, which gave rise to tumors when injected in mice. Thus, beyond the oncomodulation model, this review will assess the direct transforming role of HMCV-infected cells and the potential classification of HCMV as an oncovirus.

Knockdown of TWIST enhances the cytotoxicity of chemotherapeutic drugs in doxorubicin-resistant HepG2 cells by suppressing MDR1 and EMT

The transcription factor twist family bHLH transcription factor 1 (TWIST), which is a member of the basic helix-loop-helix class of proteins, is known to induce epithelial-mesenchymal transition (EMT) and promote cancer metastasis. TWIST has previously been reported to be associated with multidrug resistance (MDR), since its depletion increases drug sensitivity. Although these previous studies have established a strong association between EMT and MDR, the molecular mechanism remains obscure. The present study demonstrated that TWIST protein expression was elevated in liver cancer, and was positively correlated with multidrug resistance protein 1 (MDR1) expression. Conversely, MDR1 was negatively correlated with E‑cadherin expression in liver cancer samples. In addition, the present study indicated that doxorubicin-resistant HepG2 (R‑HepG2) cells acquired an EMT phenotype. TWIST was also more highly expressed in R‑HepG2 cells compared with in parental HepG2 cells. Knockdown of TWIST increased the sensitivity of R‑HepG2 cells to 5-fluroracil, cisplatin and doxorubicin through a reduction in MDR1 expression and drug efflux ability. Furthermore, knockdown of TWIST in R‑HepG2 cells inhibited the migratory ability of cells and suppressed the EMT phenotype. These findings demonstrated that targeting TWIST may be considered a novel strategy to overcome drug resistance in liver cancer.

An extracellular matrix (ECM) model at high malignant colorectal tumor increases chondroitin sulfate chains to promote epithelial-mesenchymal transition and chemoresistance acquisition

Chemoresistance is one of the major barriers for tumor chemotherapy. It is clinically known that chemoresistance increases during tumor progression. Additionally, the extracellular matrix (ECM) is also remodeled during tumor progression. However, it remains unclear how ECM remodeling contributes to chemoresistance acquisition. Recently, it has been reported that epithelial-mesenchymal transition (EMT) contributes to chemoresistance acquisition. Here, how ECM remodeling contributes to 5-fluorouracil (5-FU) resistance acquisition was investigated from the viewpoints of EMT using in vitro ECM models mimicking native ECM in colorectal tumor tissue at three different malignant levels. 5-FU partially induced EMT and increased ABCB1 in colorectal HT-29 cells via TGF-β signaling (an invasive tumor cell model). When HT-29 cells were cultured on an ECM model (high malignant matrices) mimicking native ECM in highly malignant tumor tissues, the cells facilitated TGF-β-induced EMT and increased ABCB1 upregulation compared with that of other ECM models mimicking the low malignant level and normal tissues. High malignant matrices contained more chondroitin sulfate (CS) chains than those of other ECM models. Finally, CS chain-reduced high malignant matrices could not facilitate ABCB1 upregulation and TGF-β-induced EMT. These results demonstrated that ECM remodeling during tumor progression increased CS chains to facilitate EMT and ABCB1 upregulation, contributing to chemoresistance acquisition.

Epithelial-mesenchymal-transition-inducing transcription factors: new targets for tackling chemoresistance in cancer?

Chemoresistance remains a major complication of cancer treatments. Recent data provide strong evidence that chemoresistance is linked to epithelial-mesenchymal transition (EMT), a latent developmental process, which is re-activated during cancer progression. EMT involves transcriptional reprogramming and is driven by specific EMT transcription factors (EMT-TFs). In this review, we provide support for the idea that EMT-TFs contribute to the development of resistance against cancer therapy and discuss how EMT-TFs might be targeted to advance novel therapeutic approaches to the treatment of cancer.

Analysis of the expression of cancer-associated fibroblast- and EMT-related proteins in submucosal invasive colorectal cancer

Objective: Recent studies have shown that cancer-associated fibroblasts (CAFs) and the epithelial-mesenchymal transition (EMT) play important roles in the progression and metastasis of CRC. Although prediction of lymph node metastasis in submucosal invasive colorectal cancer (SiCRC) is important, the relationships of CAF and EMT with lymph node metastasis of SiCRC have not yet been examined. Here, we aimed to analyze the expression patterns of CAF- and EMT-related proteins in SiCRC.

Materials and Methods: The expression of CAF-related markers, including α-smooth muscle actin, CD10, podoplanin, fibroblast specific protein 1, and adipocyte enhancer-binding protein 1, and EMT-related proteins [zinc finger protein SNAI2 (ZEB1) and twist-related protein 1 (TWIST1) in SiCRC with (n = 29) or without (n = 80) lymph node metastasis was examined by immunohistochemistry. We examined the expression patterns of biomarkers using hierarchical cluster analysis. Consequently, four subgroups were established based on the expression patterns of CAF- and EMT-related markers, and the associations of these subgroups with clinicopathological variables.

Results: In multivariate analysis, subgroup 2, which was characterized by high expression of all markers, was correlated with lymph node metastasis (p < 0.01). Next, we examined the associations of individual biomarkers with lymph node metastasis. Multivariate analysis showed that moderately differentiated adenocarcinoma was significantly associated with lymph node metastasis (p < 0.05).

Conclusions: Our findings showed that expression patterns of CAF markers and EMT-related proteins may allow for stratification of patients into risk categories for lymph node metastasis in SiCRC.

LncRNA CHRF-induced miR-489 loss promotes metastasis of colorectal cancer via TWIST1/EMT signaling pathway

microRNA-489 (miR-489) is a novel cancer-related miRNAs and functions as a tumor suppressor in human cancers. While, the clinical significance of miR-489 and its role in colorectal cancer (CRC) remain rarely known. Here, we found that the levels of miR-489 in CRC tissues were significantly lower than those in matched tumor-adjacent tissues. Furthermore, decreased levels of miR-489 also observed in CRC cell lines compared to HIEC cells. Clinicopathological analysis revealed that miR-489 underexpression was positively correlated with advanced pT stage, pN stage and AJCC stage. Moreover, miR-489 low expressing CRC patients showed a obvious shorter survival. Functionally, miR-489 restoration inhibited cell migration and invasion as well as epithelial-mesenchymal transition (EMT) in HCT116 cells, while miR-489 loss facilitated these cellular processes in SW480 cells. In vivo experiments revealed that miR-489 overexpression reduced the number of metastatic nodules in nude mice liver. Notably, TWIST1 was recognized as a direct downstream target of miR-489 in CRC cells. Interestingly, TWIST1 restoration abrogated the effects of miR-489 on CRC cells with enhanced cell migration, invasion and EMT process. Furthermore, overexpression of long noncoding RNA cardiac hypertrophy-related factor (lncRNA CHRF) was inversely correlated with miR-489 expression in CRC tissues. CHRF knockdown increased the expression of miR-489 and suppressed EMT events of HCT116 cells, while CHRF overexpression showed opposite effects on miR-489 expression and EMT in SW480 cells. Taken together, this work support the first evidence that lncRNA CHRF-induced miR-489 loss facilitates metastasis and EMT process of CRC cells probably via TWIST1/EMT signaling pathway.

HK3 overexpression associated with epithelial-mesenchymal transition in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is a common cancer worldwide. The main cause of death in CRC includes tumor progression and metastasis. At molecular level, these processes may be triggered by epithelial-mesenchymal transition (EMT) and necessitates specific alterations in cell metabolism. Although several EMT-related metabolic changes have been described in CRC, the mechanism is still poorly understood.

RESULTS

Using CrossHub software, we analyzed RNA-Seq expression profile data of CRC derived from The Cancer Genome Atlas (TCGA) project. Correlation analysis between the change in the expression of genes involved in glycolysis and EMT was performed. We obtained the set of genes with significant correlation coefficients, which included 21 EMT-related genes and a single glycolytic gene, HK3. The mRNA level of these genes was measured in 78 paired colorectal cancer samples by quantitative polymerase chain reaction (qPCR). Upregulation of HK3 and deregulation of 11 genes (COL1A1, TWIST1, NFATC1, GLIPR2, SFPR1, FLNA, GREM1, SFRP2, ZEB2, SPP1, and RARRES1) involved in EMT were found. The results of correlation study showed that the expression of HK3 demonstrated a strong correlation with 7 of the 21 examined genes (ZEB2, GREM1, TGFB3, TGFB1, SNAI2, TWIST1, and COL1A1) in CRC.

CONCLUSIONS

Upregulation of HK3 is associated with EMT in CRC and may be a crucial metabolic adaptation for rapid proliferation, survival, and metastases of CRC cells.

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.

Hierarchical clustering analysis identifies metastatic colorectal cancers patients with more aggressive phenotype

A large percentage of metastatic colorectal cancer (mCRC) patients presents metastasis at the time of diagnosis. In the last years, great efforts have been made in the treatment of these patients with the identification of different phenotypes playing a key role in the definition of new systemic therapies. Unsupervised hierarchical clustering analysis (HCA) was performed considering the clinicopathological characteristics of 51 mCRCs. Using immunohistochemistry on tissue microarrays, we assessed the expression of β-catenin, NHERF1, RASSF1A, TWIST1, HIF-1α proteins in tumors and paired liver metastases. We also analyzed RASSF1A methylation status on the samples of the same patients. HCA distinguished Group 1 and Group 2 characterized by different clinicopathological features. Group 1 was characterized by higher number of positive lymph nodes (p=0.0139), poorly differentiated grade (p<0.0001) and high extent of tumor spread (p=0.0053) showing a more aggressive phenotype compared to Group 2. In both Groups, we found a common "basal" condition with a higher level of nuclear TWIST1 (p<0.0001 and cytoplasmic β-catenin (p<0.0001) in tumors than in paired liver metastases. Furthermore, the Group 1 was also characterized by RASSF1A hypermethylation (p<0.0001) and nuclear HIF-1α overexpression (p=0.0354) in paired liver metastases than in tumors. In conclusion, HCA identifies mCRC patients with a more aggressive phenotype. Moroever, our results support the important contribution to the progression of the disease of RASSF1A methylation and the oncogenic role of HIF-1α in these patients. These evidences, should provide relevant information concerning the biology of this tumor and, as a consequence, potential new systemic therapeutic approaches.

Small interfering RNA-mediated knockdown of Twist attenuates the aggressive phenotypes of human endometrial carcinoma Ishikawa cells

The present study aimed to determine the effect of Twist downregulation on the proliferation, apoptosis and migration of human endometrial carcinoma Ishikawa cells. Endogenous expression of the Twist transcription factor was knocked down by delivery of Twist-targeting small interfering RNA (siRNA). Changes in the expression of epithelial-mesenchymal transition biomarkers, namely epithelial (E)-cadherin, neural (N)-cadherin and Twist, were determined by western blot analysis. Cell cycle distribution and apoptosis were evaluated by flow cytometry. Cell proliferation and migration were analyzed using cell-counting and wound-healing assays, respectively. Transfection with Twist siRNA led to a significant reduction in the expression of Twist and N-cadherin (P<0.05), while significantly increasing the expression of E-cadherin, relative to negative control transfectants (all P<0.05). Proliferation was also significantly decreased in Ishikawa cells transfected with Twist siRNA (P<0.05), which was accompanied by an increased rate of apoptosis and cell cycle arrest at S-phase. In addition, Twist downregulation led to a significant reduction in cell migration (P<0.05). These data suggest that Twist serves a role in the regulation of cell proliferation and migration in Ishikawa cells and may represent a potential target for the treatment of human endometrial carcinoma.

Multiple biological functions of Twist1 in various cancers

Twist1 is a well-known regulator of transcription during embryonic organogenesis in many species. In humans, Twist1 malfunction was first linked to Saethre-Chotzen syndrome and later identified to play an essential role in tumor initiation, stemness, angiogenesis, invasion, metastasis, and chemo-resistance in a variety of carcinomas, sarcomas, and hematological malignances. In this review, we will first focus on systematically elaborating the diverse pathological functions of Twist1 in various cancers, then delineating the intricate underlying network of molecular mechanisms, based on which we will summarize current therapeutic strategies in cancer treatment that target and modulate Twist1-involved signaling pathways. Most importantly, we will put special emphasis on revealing the independence and interdependency of these multiple biological functions of Twist1, piecing together the whole delicate picture of Twist1's diversified pathological roles in different cancers and providing new perspectives to guide future research.

HES1 Promotes Colorectal Cancer Cell Resistance To 5-Fu by Inducing Of EMT and ABC Transporter Proteins

Background and Aim: Hairy enhancer of split-1 (HES1) is a downstream transcriptional factor of Notch signaling pathway, which was found to be related to chemoresistance. This study was aimed to investigate the role of HES1 in chemoresistance of colorectal cancer (CRC). Methods: Tissue microarray was used to analyze the clinical significance of HES1 in radical resected (R0) stage II/III CRC patients that received adjuvant chemotherapy. 5-fluorouracil (5-Fu) chemoresistance was examined in CRC cell lines (RKO and HCT8, LOVO) with stable over-expression and inhibition of HES1 gene by cytotoxicity test. Gene expression microarray was used to investigate the enriched pathways and different expressed of genes in cells with over-expressed HES1. Expression changes of the chemoresistance related genes were confirmed by qPCR and western blot analysis. Results: Stage II CRC patients with higher HES1 expression showed higher recurrence rate after chemotherapy. Colon cancer cell lines which over-expressed HES1 were more resistant to 5-Fu treatment in vitro. Gene expression microarray revealed that HES1 was related to the signaling pathways of epithelial-mesenchymal transition (EMT) and drug metabolism. Immunofluorescence assay showed HES1 over-expression lead to depressed E-cadherin and elevated N-cadherin. QPCR and western blot analysis confirmed that ABCC1, ABCC2 and P-gp1 were induced after HES1 over-expression. Conclusions: HES1 promotes chemoresistance to 5-Fu by prompting EMT and inducing of several ABC transporter genes. HES1 might be a novel therapeutic target in CRC treatment.

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.