scholarly journals Understanding the Complex Milieu of Epithelial-Mesenchymal Transition in Cancer Metastasis: New Insight Into the Roles of Transcription Factors

2021 ◽  
Vol 11 ◽  
Author(s):  
Sikiru O. Imodoye ◽  
Kamoru A. Adedokun ◽  
Abdurrasheed Ola Muhammed ◽  
Ibrahim O. Bello ◽  
Musa A. Muhibi ◽  
...  

Epithelial-mesenchymal transition (EMT) is a physiological program during which polarised, immobile epithelial cells lose connection with their neighbours and are converted to migratory mesenchymal phenotype. Mechanistically, EMT occurs via a series of genetic and cellular events leading to the repression of epithelial-associated markers and upregulation of mesenchymal-associated markers. EMT is very crucial for many biological processes such as embryogenesis and ontogenesis during human development, and again it plays a significant role in wound healing during a programmed replacement of the damaged tissues. However, this process is often hijacked in pathological conditions such as tumour metastasis, which constitutes the most significant drawback in the fight against cancer, accounting for about 90% of cancer-associated mortality globally. Worse still, metastatic tumours are not only challenging to treat with the available conventional radiotherapy and surgical interventions but also resistant to several cytotoxic agents during treatment, owing to their anatomically diffuse localisation in the body system. As the quest to find an effective method of addressing metastasis in cancer intervention heightens, understanding the molecular interplay involving the signalling pathways, downstream effectors, and their interactions with the EMT would be an important requisite while the challenges of metastasis continue to punctuate. Unfortunately, the molecular underpinnings that govern this process remain to be completely illuminated. However, it is becoming increasingly clear that EMT, which initiates every episode of metastasis, significantly requires some master regulators called EMT transcription factors (EMT-TFs). Thus, this review critically examines the roles of TFs as drivers of molecular rewiring that lead to tumour initiation, progression, EMT, metastasis, and colonisation. In addition, it discusses the interaction of various signalling molecules and effector proteins with these factors. It also provides insight into promising therapeutic targets that may inhibit the metastatic process to overcome the limitation of “undruggable” cancer targets in therapeutic design and upturn the current spate of drug resistance. More so, it extends the discussion from the basic understanding of the EMT binary switch model, and ultimately unveiling the E/M cellular plasticity along a phenotypic spectrum via multiple trans-differentiations. It wraps up on how this knowledge update shapes the diagnostic and clinical approaches that may demand a potential shift in investigative paradigm using novel technologies such as single-cell analyses to improve overall patient survival.

2018 ◽  
Vol 19 (12) ◽  
pp. 3968 ◽  
Author(s):  
Enrico Spugnini ◽  
Mariantonia Logozzi ◽  
Rossella Di Raimo ◽  
Davide Mizzoni ◽  
Stefano Fais

Metastatic diffusion is thought to be a multi-step phenomenon involving the release of cells from the primary tumor and their diffusion through the body. Currently, several hypotheses have been put forward in order to explain the origin of cancer metastasis, including epithelial–mesenchymal transition, mutagenesis of stem cells, and a facilitating role of macrophages, involving, for example, transformation or fusion hybridization with neoplastic cells. In this paradigm, tumor-secreted extracellular vesicles (EVs), such as exosomes, play a pivotal role in cell communications, delivering a plethora of biomolecules including proteins, lipids, and nucleic acids. For their natural role in shuttling molecules, EVs have been newly considered a part of the metastatic cascade. They have a prominent role in preparing the so-called “tumor niches” in target organs. However, recent evidence has pointed out an even more interesting role of tumor EVs, consisting in their ability to induce malignant transformation in resident mesenchymal stem cells. All in all, in this review, we discuss the multiple involvements of EVs in the metastatic cascade, and how we can exploit and manipulate EVs in order to reduce the metastatic spread of malignant tumors.


2016 ◽  
Vol 1 (1) ◽  
pp. 48
Author(s):  
Khemraj Singh Baghel ◽  
Smrati Bhadauria

Metastatic breast cancer is a stage of breast cancer wherever the disease has spread to distant parts of the body. Onset of metastasis is one of the biggest obstacles to the successful treatment of cancer. The potential of a tumor cell to metastasize profoundly depends on its microenvironment, or “niche” interactions with local components. Macrophages provide tropic support to tumors. Resident macrophages contribute a set of common functions, including their capability to defend against microbial infections, to maintain normal cell turnover and tissue remodelling, and to help repair sites of injury. Macrophages are recruited into the tumor microenvironment where they differentiate to become Tumor-associated-macrophages (TAMs). TAMs are the most abundant subpopulation of tumor-stroma and actively drive cancer cell invasion and metastasis. Cancer metastasis is not solely regulated by the deregulation of metastasis promoting or suppressing genes in cancer cells. Recently the interaction between the stromal cells and cancer cells has been demonstrated to promote cancer metastasis. TAMs can advocate epithelial-mesenchymal transition of cancer cells. Loss of e-cadherin, a major phenomenon of epithelial to mesenchymal transition (EMT), reduces adhesiveness and releases cancer cells to distant (secondary) sites. A positive correlation between tumor progression and the expression of matrix metallo proteinases (MMPs) in tumor tissues has been demonstrated in numerous human and animal studies. The dynamic interactions of cancer-cells with TAMs actively promote invasion-metastasis cascade through intercellular-signalling-networks that need better elucidation.


2016 ◽  
Vol 22 (2) ◽  
pp. 136-143 ◽  
Author(s):  
Wendao You ◽  
Liang Xu ◽  
Xing Zhang ◽  
Huan Zou ◽  
Dongtao Shi ◽  
...  

MicroRNAs (miRNAs) are globally dysregulated in human carcinomas. However, the specific miRNAs that mediate gastric cancer metastasis have not been identified. We identified 100 miRNAs that are dysregulated in gastric cancer and used a self-assembled cell microarray method to systematically evaluate their capacity to regulate cell migration. MiR-451, which is down-regulated in human gastric cancer samples, potently modulated multiple metastatic phenotypes including cell migration, invasion, proliferation, and epithelial-mesenchymal transition. These effects were achieved via down-regulation of the miR-451 target gene, ERK2. These findings provide new insight into the physiological effects of and potential therapeutic uses for miRNAs in gastric cancer.


2012 ◽  
Vol 2012 ◽  
pp. 1-11 ◽  
Author(s):  
Yong-Nyun Kim ◽  
Kyung Hee Koo ◽  
Jee Young Sung ◽  
Un-Jung Yun ◽  
Hyeryeong Kim

Metastasis is a multistep process including dissociation of cancer cells from primary sites, survival in the vascular system, and proliferation in distant target organs. As a barrier to metastasis, cells normally undergo an apoptotic process known as “anoikis,” a form of cell death due to loss of contact with the extracellular matrix or neighboring cells. Cancer cells acquire anoikis resistance to survive after detachment from the primary sites and travel through the circulatory and lymphatic systems to disseminate throughout the body. Because recent technological advances enable us to detect rare circulating tumor cells, which are anoikis resistant, currently, anoikis resistance becomes a hot topic in cancer research. Detailed molecular and functional analyses of anoikis resistant cells may provide insight into the biology of cancer metastasis and identify novel therapeutic targets for prevention of cancer dissemination. This paper comprehensively describes recent investigations of the molecular and cellular mechanisms underlying anoikis and anoikis resistance in relation to intrinsic and extrinsic death signaling, epithelial-mesenchymal transition, growth factor receptors, energy metabolism, reactive oxygen species, membrane microdomains, and lipid rafts.


2021 ◽  
Author(s):  
Pallabi Debnath ◽  
Rohit Singh Huirem ◽  
Paloma Dutta ◽  
Santanu Palchaudhuri

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


2021 ◽  
Vol 22 (7) ◽  
pp. 3591
Author(s):  
Eunjeong Kang ◽  
Jihye Seo ◽  
Haelim Yoon ◽  
Sayeon Cho

Epithelial–mesenchymal transition (EMT) is generally observed in normal embryogenesis and wound healing. However, this process can occur in cancer cells and lead to metastasis. The contribution of EMT in both development and pathology has been studied widely. This transition requires the up- and down-regulation of specific proteins, both of which are regulated by EMT-inducing transcription factors (EMT-TFs), mainly represented by the families of Snail, Twist, and ZEB proteins. This review highlights the roles of key EMT-TFs and their post-translational regulation in cancer metastasis.


2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Rong Xu ◽  
Jae-Yeon Won ◽  
Chang-Hyeon Kim ◽  
Da-Eun Kim ◽  
Hyungshin Yim

Epithelial-to-mesenchymal transition (EMT) is the first step in the development of the invasive and migratory properties of cancer metastasis. Since the transcriptional reprogramming of a number of genes occurs in EMT, the regulation of EMT transcription factors has been intensively investigated. EMT transcriptional factors are commonly classified by the direct or indirect repression of E-cadherin because one of hallmarks of EMT is the loss of E-cadherin. This facilitates the expression of genes for EMT, tumor invasion, and metastasis. The posttranslational modification of EMT transcriptional factors, such as Snail and Slug, directly regulates their functions, including their stability, nuclear localization, protein-protein interaction, and ubiquitination for the promotion or termination of EMT at the specific points. Here, we discuss how posttranslational modifications regulate gene expression in a dynamic and reversible manner by modifying upstream signaling pathways, focusing in particular on the posttranslational modifications of Snail, Slug, ZEB1, ZEB2, and TWIST1. This review demonstrates that EMT transcription factors regulate metastasis through their posttranslational modifications and that the flexibility and reversibility of EMT can be modified by phosphorylation.


Cancers ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 179
Author(s):  
Abeer Alharbi ◽  
Yuxuan Zhang ◽  
John Parrington

Metastatic cancer is one of the major causes of cancer-related mortalities. Metastasis is a complex, multi-process phenomenon, and a hallmark of cancer. Calcium (Ca2+) is a ubiquitous secondary messenger, and it has become evident that Ca2+ signalling plays a vital role in cancer. Ca2+ homeostasis is dysregulated in physiological processes related to tumour metastasis and progression—including cellular adhesion, epithelial–mesenchymal transition, cell migration, motility, and invasion. In this review, we looked at the role of intracellular and extracellular Ca2+ signalling pathways in processes that contribute to metastasis at the local level and also their effects on cancer metastasis globally, as well as at underlying molecular mechanisms and clinical applications. Spatiotemporal Ca2+ homeostasis, in terms of oscillations or waves, is crucial for hindering tumour progression and metastasis. They are a limited number of clinical trials investigating treating patients with advanced stages of various cancer types. Ca2+ signalling may serve as a novel hallmark of cancer due to the versatility of Ca2+ signals in cells, which suggests that the modulation of specific upstream/downstream targets may be a therapeutic approach to treat cancer, particularly in patients with metastatic cancers.


Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 558
Author(s):  
Jin Kyung Seok ◽  
Eun-Hee Hong ◽  
Gabsik Yang ◽  
Hye Eun Lee ◽  
Sin-Eun Kim ◽  
...  

Oxidized phospholipids are well known to play physiological and pathological roles in regulating cellular homeostasis and disease progression. However, their role in cancer metastasis has not been entirely understood. In this study, effects of oxidized phosphatidylcholines such as 1-palmitoyl-2-(5-oxovaleroyl)-sn-glycero-3-phosphocholine (POVPC) on epithelial-mesenchymal transition (EMT) and autophagy were determined in cancer cells by immunoblotting and confocal analysis. Metastasis was analyzed by a scratch wound assay and a transwell migration/invasion assay. The concentrations of POVPC and 1-palmitoyl-2-glutaroyl-sn-glycero-phosphocholine (PGPC) in tumor tissues obtained from patients were measured by LC-MS/MS analysis. POVPC induced EMT, resulting in increase of migration and invasion of human hepatocellular carcinoma cells (HepG2) and human breast cancer cells (MCF7). POVPC induced autophagic flux through AMPK-mTOR pathway. Pharmacological inhibition or siRNA knockdown of autophagy decreased migration and invasion of POVPC-treated HepG2 and MCF7 cells. POVPC and PGPC levels were greatly increased at stage II of patient-derived intrahepatic cholangiocarcinoma tissues. PGPC levels were higher in malignant breast tumor tissues than in adjacent nontumor tissues. The results show that oxidized phosphatidylcholines increase metastatic potential of cancer cells by promoting EMT, mediated through autophagy. These suggest the positive regulatory role of oxidized phospholipids accumulated in tumor microenvironment in the regulation of tumorigenesis and metastasis.


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