Small Molecular Approaches for Cellular Reprogramming and Tissue Engineering: Functions as Mediators of the Cell Signaling Pathway

Utilizing induced pluripotent stem cells (iPSCs) in drug screening and cell replacement therapy has emerged as a method with revolutionary applications. With the advent of patient-specific iPSCs and the subsequent development of cells that exhibit disease phenotypes, the focus of medication research will now shift toward the pathology of human diseases. Regular iPSCs can also be utilized to generate cells that assess the negative impacts of medications. These cells provide a much more precise and cost-efficient approach compared to many animal models. In this review, we explore the utilization of small-molecule drugs to enhance the growth of iPSCs and gain insights into the process of reprogramming. We mainly focus on the functions of small molecules in modulating different signaling pathways, thereby modulating cell fate. Understanding the way small molecule drugs interact with iPSC technology has the potential to significantly enhance the understanding of physiological pathways in stem cells and practical applications of iPSC-based therapy and screening systems, revolutionizing the treatment of diseases.

Phenotypic Transitions the Processes Involved in Regulation of Growth and Proangiogenic Properties of Stem Cells, Cancer Stem Cells and Circulating Tumor Cells

Epithelial-mesenchymal transition (EMT) is a crucial process with significance in the metastasis of malignant tumors. It is through the acquisition of plasticity that cancer cells become more mobile and gain the ability to metastasize to other tissues. The mesenchymal-epithelial transition (MET) is the return to an epithelial state, which allows for the formation of secondary tumors. Both processes, EMT and MET, are regulated by different pathways and different mediators, which affects the sophistication of the overall tumorigenesis process. Not insignificant are also cancer stem cells and their participation in the angiogenesis, which occur very intensively within tumors. Difficulties in effectively treating cancer are primarily dependent on the potential of cancer cells to rapidly expand and occupy secondarily vital organs. Due to the ability of these cells to spread, the concept of the circulating tumor cell (CTC) has emerged. Interestingly, CTCs exhibit molecular diversity and stem-like and mesenchymal features, even when derived from primary tumor tissue from a single patient. While EMT is necessary for metastasis, MET is required for CTCs to establish a secondary site. A thorough understanding of the processes that govern the balance between EMT and MET in malignancy is crucial.

Tumor Microenvironment Modulation by Cancer-Derived Extracellular Vesicles

The tumor microenvironment (TME) plays an important role in the process of tumorigenesis, regulating the growth, metabolism, proliferation, and invasion of cancer cells, as well as contributing to tumor resistance to the conventional chemoradiotherapies. Several types of cells with relatively stable phenotypes have been identified within the TME, including cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), neutrophils, and natural killer (NK) cells, which have been shown to modulate cancer cell proliferation, metastasis, and interaction with the immune system, thus promoting tumor heterogeneity. Growing evidence suggests that tumor-cell-derived extracellular vesicles (EVs), via the transfer of various molecules (e.g., RNA, proteins, peptides, and lipids), play a pivotal role in the transformation of normal cells in the TME into their tumor-associated protumorigenic counterparts. This review article focuses on the functions of EVs in the modulation of the TME with a view to how exosomes contribute to the transformation of normal cells, as well as their importance for cancer diagnosis and therapy.

Clinical impact of epithelial–mesenchymal transition for cancer therapy

The epithelial–mesenchymal transition (EMT) represents a pivotal frontier in oncology, playing a central role in the metastatic cascade of cancer—a leading global health challenge. This comprehensive review delves into the complexities of EMT, a process where cancer cells gain exceptional mobility, facilitating their invasion into distant organs and the establishment of secondary malignancies. We thoroughly examine the myriad of factors influencing EMT, encompassing transcription factors, signalling pathways, metabolic alterations, microRNAs, long non‐coding RNAs, epigenetic changes, exosomal interactions and the intricate dynamics of the tumour microenvironment. Particularly, the review emphasises the advanced stages of EMT, crucial for the development of highly aggressive cancer phenotypes. During this phase, cancer cells penetrate the vascular barrier and exploit the bloodstream to propagate life‐threatening metastases through the mesenchymal–epithelial transition. We also explore EMT's significant role in fostering tumour dormancy, senescence, the emergence of cancer stem cells and the formidable challenge of therapeutic resistance. Our review transcends a mere inventory of EMT‐inducing elements; it critically assesses the current state of EMT‐focused clinical trials, revealing both the hurdles and significant breakthroughs. Highlighting the potential of EMT research, we project its transformative impact on the future of cancer therapy. This exploration is aimed at paving the way towards an era of effectively managing this relentless disease, positioning EMT at the forefront of innovative cancer research strategies.

Inactivation of Tumor Suppressor CYLD Inhibits Fibroblast Reprogramming to Pluripotency

CYLD is a tumor suppressor gene coding for a deubiquitinating enzyme that has a critical regulatory function in a variety of signaling pathways and biological processes involved in cancer development and progression, many of which are also key modulators of somatic cell reprogramming. Nevertheless, the potential role of CYLD in this process has not been studied. With the dual aim of investigating the involvement of CYLD in reprogramming and developing a better understanding of the intricate regulatory system governing this process, we reprogrammed control (CYLDWT/WT) and CYLD DUB-deficient (CYLDΔ9/Δ9) mouse embryonic fibroblasts (MEFs) into induced pluripotent stem cells (iPSCs) through ectopic overexpression of the Yamanaka factors (Oct3/4, Sox2, Klf4, c-myc). CYLD DUB deficiency led to significantly reduced reprogramming efficiency and slower early reprogramming kinetics. The introduction of WT CYLD to CYLDΔ9/Δ9 MEFs rescued the phenotype. Nevertheless, CYLD DUB-deficient cells were capable of establishing induced pluripotent colonies with full spontaneous differentiation potential of the three germ layers. Whole proteome analysis (Data are available via ProteomeXchange with identifier PXD044220) revealed that the mesenchymal-to-epithelial transition (MET) during the early reprogramming stages was disrupted in CYLDΔ9/Δ9 MEFs. Interestingly, differentially enriched pathways revealed that the primary processes affected by CYLD DUB deficiency were associated with the organization of the extracellular matrix and several metabolic pathways. Our findings not only establish for the first time CYLD's significance as a regulatory component of early reprogramming but also highlight its role as an extracellular matrix regulator, which has profound implications in cancer research.

Proteomic Analysis and Reprogramming Potential of the Porcine Intra-Ooplasmic Nanovesicles

Oocytes contain reprogramming machinery that can transform somatic cells into totipotent cells. In this study, we aimed to isolate and characterize nanovesicles from mature porcine oocytes and described them for the first time as "intra-ooplasmic vesicles (IOVs)". Isolated IOVs had an average diameter of 186.3 ± 10.8 nm. Proteomic analysis revealed 467 peptide reads, with the top 20 proteins related to reprogramming, antioxidative defense, cytoskeleton, heat shock proteins, and metabolism. Protein-protein interaction and gene ontology analysis indicated that these proteins were involved in various biological pathways, including protein folding, metabolism, and cellular responses to stress. Supplementing cultured fibroblasts with IOVs resulted in the expression of the pluripotency marker OCT4 and the early trophoblastic marker CDX2 and increased expression of the corresponding mRNAs together with increasing KLF4 and SALL4 expression. IOV treatment of fibroblasts for 14 consecutive days resulted in changes in cell morphology, with increased expression of ZEB2 and YBX3 as markers for epithelial-to-mesenchymal transition (EMT). These results provide a rationale for further characterization of IOVs, investigation of potential reprogramming capabilities for EMT, and the generation of induced pluripotent or oligopotent stem cells.

Current progress in bionanomaterials to modulate the epigenome

Recent advances in genomics during the 1990s have made it possible to study and identify genetic and epigenetic responses of cells and tissues to various drugs and environmental factors. This has accelerated the number of targets available to treat a range of diseases from cancer to wound healing disorders. Equally interesting is the understanding of how bio- and nanomaterials alter gene expression through epigenetic mechanisms, and whether they have the potential to elicit a positive therapeutic response without requiring additional biomolecule delivery. In fact, from a cell's perspective, a biomaterial is nothing more than an environmental factor, and so it has the power to epigenetically modulate gene expression of cells in contact with it. Understanding these epigenetic interactions between biomaterials and cells will open new avenues in the development of technologies that can not only provide biological signals (i.e. drugs, growth factors) necessary for therapy and regeneration, but also intimately interact with cells to promote the expression of genes of interest. This review article aims to summarise the current state-of-the-art and progress on the development of bio- and nanomaterials to modulate the epigenome.

E-cadherin and N-cadherin Immunohistochemical Expression in Proliferating Urothelial Lesions: Potential Novel Cancer Predictive EMT Profiles

Cadherin switch (CS) outlined by downregulation of E-cadherin and upregulation of N-cadherin is an established epithelial-mesenchymal transition (EMT) hallmark, being a common signature in wound healing and carcinogenesis. It is intriguing to explore the EMT-associated CS pattern in precancerous phases as well as variably aggressive bladder cancer categories. In this study, we tested CS signified by a reduction in urothelial cells E-cadherin expression and/or aberrant N-cadherin expression in proliferative epithelial changes (PEC) associating inflammation, non-muscle-invasive bladder cancer (NMIBC), and muscle-invasive bladder cancer (MIBC). Immunohistochemical study of both E-cadherin and N-cadherin was performed for 60 cases: 15 PEC, 8 NMIBC, and 37 MIBC. CS patterns were analyzed: abnormal CS patterns were expressed as deviated, hybrid, co-negative, and full CS patterns. E-cadherin expression was significantly preserved in PEC (86.7%) followed by NMIBC (62.5%) and then MIBC (37.8%) (P=0.004), whereas N-cadherin showed obvious aberrant expression in MIBC (51.4%) as compared with PEC (33.3%) and NMIBC (25%). In the MIBC group, abnormal cadherin patterns were the highest (70.3%) and was associated with adverse prognostic indicators. In the context of NMIBC progression to MIBC, combined E and N-cadherin evaluation showed highest sensitivity (70.3%) and NPV (31.3%), whereas aberrant expression of N-cadherin presented highest specificity (75%) and positive predictive value (90.5%). For cancer prediction, combined E-cadherin and N-cadherin evaluation showed the highest sensitivity (64.4%); abnormal E-cadherin offered highest specificity (86.7%), positive predictive value (92.9%), and negative predictive value (40.6%). In posttherapy follow-up setting, a metastable EMT signature in the form of partial CS was noted and might reflect resistant dormant populations.

Cripto-1 as a Key Factor in Tumor Progression, Epithelial to Mesenchymal Transition and Cancer Stem Cells

Cripto-1 is an essential protein for human development that plays a key role in the early phase of gastrulation in the differentiation of an embryo as well as assists with wound healing processes. Importantly, Cripto-1 induces epithelial to mesenchymal transition to turn fixed epithelial cells into a more mobile mesenchymal phenotype through the downregulation of epithelial adhesion molecules such as E-cadherin, occludins, and claudins, and the upregulation of mesenchymal, mobile proteins, such as N-cadherin, Snail, and Slug. Consequently, Cripto-1’s role in inducing EMT to promote cell motility is beneficial in embryogenesis, but detrimental in the formation, progression and metastasis of malignant tumors. Indeed, Cripto-1 is found to be upregulated in most cancers, such as breast, lung, gastrointestinal, hepatic, renal, cervical, ovarian, prostate, and skin cancers. Through its role in EMT, Cripto-1 can remodel cancer cells to enable them to travel through the extracellular matrix as well as blood and lymphatic vessels to metastasize to different organs. Additionally, Cripto-1 promotes the survival of cancer stem cells, which can lead to relapse in cancer patients.

Stepwise Induction of Inner Ear Hair Cells From Mouse Embryonic Fibroblasts via Mesenchymal- to-Epithelial Transition and Formation of Otic Epithelial Cells

Although embryonic stem cells or induced pluripotent stem cells are able to differentiate into inner ear hair cells (HCs), they have drawbacks limiting their clinical application, including a potential risk of tumourigenicity. Direct reprogramming of fibroblasts to inner ear HCs could offer an alternative solution to this problem. Here, we present a stepwise guidance protocol to induce mouse embryonic fibroblasts to differentiate into inner ear HC-like cells (HCLs) via mesenchymal-to-epithelial transition and then acquisition of otic sensory epithelial cell traits by overexpression of three key transcription factors. These induced HCLs express multiple HC-specific proteins, display protrusions reminiscent of ciliary bundle structures, respond to voltage stimulation, form functional mechanotransduction channels, and exhibit a transcriptional profile of HC signature. Together, our work provides a new method to produce functional HCLs in vitro, which may have important implications for studies of HC development, drug discovery, and cell replacement therapy for hearing loss.

ΕGFR/ERβ-Mediated Cell Morphology and Invasion Capacity Are Associated with Matrix Culture Substrates in Breast Cancer

Breast cancer accounts for almost one in four cancer diagnoses in women. Studies in breast cancer patients have identified several molecular markers, indicators of aggressiveness, which help toward more individual therapeutic approaches. In triple-negative breast cancer (TNBC), epidermal growth factor receptor (EGFR) overexpression is associated with increased metastatic potential and worst survival rates. Specifically, abnormal EGFR activation leads to altered matrix metalloproteinases' (MMPs) expression and, hence, extracellular matrix (ECM) degradation, resulting in induced migration and invasion. The use of matrix substrates for cell culture gives the opportunity to mimic the natural growth conditions of the cells and their microenvironment, as well as cell-cell and cell-matrix interactions. The aim of this study was to evaluate the impact of EGFR inhibition, estrogen receptor beta (ERβ) and different matrix substrates [type I collagen and fibronectin (FN)] on the functional properties, expression of MMPs and cell morphology of ERβ-positive TNBC cells and shERβ ones. Our results highlight EGFR as a crucial regulator of the expression and activity levels of MMPs, while ERβ emerges as a mediator of MMP7 and MT1-MMP expression. In addition, the EGFR/ERβ axis impacts the adhesion and invasion potential of breast cancer cells on collagen type I. Images obtained by scanning electron microscope (SEM) from cultures on the different matrix substrates revealed novel observations regarding various structures of breast cancer cells (filopodia, extravesicles, tunneling nanotubes, etc.). Moreover, the significant contribution of EGFR and ERβ in the morphological characteristics of these cells is also demonstrated, hence highlighting the possibility of dual pharmacological targeting.

Protein Kinases and Their Inhibitors in Pluripotent Stem Cell Fate Regulation

Protein kinases modulate the reversible postmodifications of substrate proteins to their phosphorylated forms as an essential process in regulating intracellular signaling transduction cascades. Moreover, phosphorylation has recently been shown to tightly control the regulatory network of kinases responsible for the induction and maintenance of pluripotency, defined as the particular ability to differentiate pluripotent stem cells (PSCs) into every cell type in the adult body. In particular, emerging evidence indicates that the balance between the self-renewal and differentiation of PSCs is regulated by the small molecules that modulate kinase signaling pathways. Furthermore, new reprogramming technologies have been developed using kinase modulators, which have provided novel insight of the mechanisms underlying the kinase regulatory networks involved in the generation of induced pluripotent stem cells (iPSCs). In this review, we highlight the recent progress made in defining the roles of protein kinase signaling pathways and their small molecule modulators in regulating the pluripotent states, self-renewal, reprogramming process, and lineage differentiation of PSCs.

RNF43 ubiquitinates and degrades phosphorylated E-cadherin by c-Src to facilitate epithelial-mesenchymal transition in lung adenocarcinoma

Background

In epithelial cells, tyrosine kinases induce tyrosine phosphorylation and ubiquitination of the E-cadherin complex, which is responsible for the epithelial-mesenchymal transition (EMT). However, the precise mechanisms remain unclear.

Methods

Protein antibody microarray analysis and E3 ligase profiling were performed to detect the unique E3 ligase underlying E-cadherin downregulation in lung adenocarcinoma tissues. Gene knockdown was performed using viral shRNA. Immunoblotting, immunofluorescence, immunoprecipitation, and xenograft models in vivo were integratively applied to explore RNF43-induced EMT in lung adenocarcinoma cell lines.

Results

Protein antibody microarray analysis and E3 ligase profiling revealed that the RING finger protein 43 (RNF43) was linked to E-cadherin downregulation within the context of c-Src activation in lung adenocarcinoma tissues. In addition, the c-Src-Caspase-8 interaction markedly increased c-Src activity. Activated c-Src phosphorylated E-cadherin at the tyrosine 797 site to initiate RNF43-mediated E-cadherin ubiquitination at lysine 816 and subsequent degradation, thus allowing the nuclear translocation of β-catenin and upregulation of Vimentin and RNF43 expression in lung adenocarcinoma cells. Decreased E-cadherin expression and increased Vimentin expression induced the EMT phenotype and promoted tumor metastasis. The Frizzled 8 (Frz8)-RNF43-induced ubiquitination of phosphorylated E-cadherin was blocked by a monoclonal antibody against the cysteine-rich domain (CRD) of Frz8 but not by antibodies against the protease domain (PA) of RNF43.

Conclusions

Our data suggest that RNF43 participates in the regulation of EMT in the metastasis of lung adenocarcinoma through the ubiquitination and degradation of phosphorylated E-cadherin by activated c-Src.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5880-1) contains supplementary material, which is available to authorized users.

Incomplete cellular reprogramming of colorectal cancer cells elicits an epithelial/mesenchymal hybrid phenotype

Background

Induced pluripotency in cancer cells by ectopic expression of pluripotency-regulating factors may be used for disease modeling of cancers. MicroRNAs (miRNAs) are negative regulators of gene expression that play important role in reprogramming somatic cells. However, studies on the miRNA expression profile and the expression patterns of the mesenchymal-epithelial transition (MET)/epithelial-mesenchymal transition (EMT) genes in induced pluripotent cancer (iPC) cells are lacking.

Methods

iPC clones were generated from two colorectal cancer (CRC) cell lines by retroviral transduction of the Yamanaka factors. The iPC clones obtained were characterized by morphology, expression of pluripotency markers and the ability to undergo in vitro tri-lineage differentiation. Genome-wide miRNA profiles of the iPC cells were obtained by microarray analysis and bioinformatics interrogation. Gene expression was done by real-time RT-PCR and immuno-staining; MET/EMT protein levels were determined by western blot analysis.

Results

The CRC-iPC cells showed embryonic stem cell-like features and tri-lineage differentiation abilities. The spontaneously-differentiated post-iPC cells obtained were highly similar to the parental CRC cells. However, down-regulated pluripotency gene expression and failure to form teratoma indicated that the CRC-iPC cells had only attained partial pluripotency. The CRC-iPC cells shared similarities in the genome-wide miRNA expression profiles of both cancer and pluripotent embryonic stem cells. One hundred and two differentially-expressed miRNAs were identified in the CRC-iPC cells, which were predicted by bioinformatics analysis be closely involved in regulating cellular pluripotency and the expression of the MET/EMT genes, possibly via the phosphatidylinositol-3 kinases-protein kinase B (PI3K-Akt) and transforming growth factor beta (TGF-β) signaling pathways. Irregular and inconsistent expression patterns of the EMT vimentin and Snai1 and MET E-cadherin and occludin proteins were observed in the four CRC-iPC clones analyzed, which suggested an epithelial/mesenchymal hybrid phenotype in the partially reprogrammed CRC cells. MET/EMT gene expression was also generally reversed on re-differentiation, also suggesting epigenetic regulation.

Conclusions

Our data support the elite model for cancer cell-reprogramming in which only a selected subset of cancer may be fully reprogrammed; partial cancer cell reprogramming may also elicit an epithelial-mesenchymal mixed phenotype, and highlight opportunities and challenges in cancer cell-reprogramming.

Electronic supplementary material

The online version of this article (10.1186/s12929-018-0461-1) contains supplementary material, which is available to authorized users.

Microenvironmental Cues Determine Tumor Cell Susceptibility to Neutrophil Cytotoxicity

We have recently shown that neutrophil antitumor cytotoxicity is Ca²⁺ dependent and is mediated by TRPM2, an H₂O₂-dependent Ca²⁺ channel. However, neutrophil antitumor activity is dependent on context and is manifested in the premetastatic niche, but not at the primary site. We therefore hypothesized that expression of TRPM2 and the consequent susceptibility to neutrophil cytotoxicity may be associated with the epithelial/mesenchymal cellular state. We found that TRPM2 expression was upregulated during epithelial-to-mesenchymal transition (EMT), and mesenchymal cells were more susceptible to neutrophil cytotoxicity. Conversely, cells undergoing mesenchymal-to-epithelial transition (MET) expressed reduced levels of TRPM2, rendering them resistant to neutrophil cytotoxicity. Cells expressing reduced levels of TRPM2 were protected from neutrophil cytotoxicity and seeded more efficiently in the premetastatic lung. These data identify TRPM2 as the link between environmental cues at the primary tumor site, tumor cell susceptibility to neutrophil cytotoxicity, and disease progression. Furthermore, these data identify EMT as a process enhancing tumor-cell immune susceptibility and, by contrast, MET as a novel mode of immune evasion.Significance: EMT is required for metastatic spread and concomitantly enhances tumor cell susceptibility to neutrophil cytotoxicity. Cancer Res; 78(17); 5050-9. ©2018 AACR.

The oncogene Etv5 promotes MET in somatic reprogramming and orchestrates epiblast/primitive endoderm specification during mESCs differentiation

Unipotent spermatogonial stem cells (SSCs) can be efficiently reprogrammed into pluripotent stem cells only by manipulating the culture condition, without introducing exogenous reprogramming factors. This phenotype raises the hypothesis that the endogenous transcription factors (TFs) in SSCs may facilitate reprogramming to acquire pluripotency. In this study, we screened a pool of SSCs TFs (Bcl6b, Lhx1, Foxo1, Plzf, Id4, Taf4b, and Etv5), and found that oncogene Etv5 could dramatically increase the efficiency of induced pluripotent stem cells (iPSCs) generation when combined with Yamanaka factors. We also demonstrated that Etv5 could promote mesenchymal-epithelial transition (MET) at the early stage of reprogramming by regulating Tet2-miR200s-Zeb1 axis. In addition, Etv5 knockdown in mouse embryonic stem cells (mESCs) could decrease the genomic 5hmC level by downregulating Tet2. Furthermore, the embryoid body assay revealed that Etv5 could positively regulate primitive endoderm specification through regulating Gata6 and negatively regulate epiblast specification by inhibiting Fgf5 expression. In summary, our findings provide insights into understanding the regulation mechanisms of Etv5 under the context of somatic reprogramming, mESCs maintenance, and differentiation.

MiR200 and miR302: Two Big Families Influencing Stem Cell Behavior

In this review, we described different factors that modulate pluripotency in stem cells, in particular we aimed at following the steps of two large families of miRNAs: the miR-200 family and the miR-302 family. We analyzed some factors tuning stem cells behavior as TGF-β, which plays a pivotal role in pluripotency inhibition together with specific miRNAs, reactive oxygen species (ROS), but also hypoxia, and physical stimuli, such as ad hoc conveyed electromagnetic fields. TGF-β plays a crucial role in the suppression of pluripotency thus influencing the achievement of a specific phenotype. ROS concentration can modulate TGF-β activation that in turns down regulates miR-200 and miR-302. These two miRNAs are usually requested to maintain pluripotency, while they are down-regulated during the acquirement of a specific cellular phenotype. Moreover, also physical stimuli, such as extremely-low frequency electromagnetic fields or high-frequency electromagnetic fields conveyed with a radioelectric asymmetric conveyer (REAC), and hypoxia can deeply influence stem cell behavior by inducing the appearance of specific phenotypes, as well as a direct reprogramming of somatic cells. Unraveling the molecular mechanisms underlying the complex interplay between externally applied stimuli and epigenetic events could disclose novel target molecules to commit stem cell fate.

G protein-coupled receptor GPR19 regulates E-cadherin expression and invasion of breast cancer cells

Dysregulation of G protein-coupled receptors (GPCRs) is known to be involved in the pathogenesis of a variety of diseases, including cancer initiation and progression. Within this family, approximately 140 GPCRs have no known endogenous ligands and these "orphan" GPCRs remain poorly characterized. The orphan GPCR GPR19 was identified and cloned 2 decades ago, but relatively little is known about its physio-pathological relevance. We observed its expression to be elevated in breast cancers and therefore sought to investigate its potential role in breast cancer pathology. In this work, we show that overexpression of GPR19 drives mesenchymal-like breast cancer cells to adopt an epithelial-like phenotype, as demonstrated by the upregulation in E-cadherin expression and changes in functional behavior. We confirm a previous report that a peptide, adropin, is an endogenous ligand for GPR19. We further show that adropin-mediated activation of GPR19 activates the MAPK/ERK1/2 pathway, which is essential for the observed upregulation in E-cadherin and accompanying phenotypic changes. The recapitulation of epithelial characteristics at the secondary tumor sites is now understood to be an essential step in the colonization process. Taken together our work shows for the first time that GPR19 plays a potential role in metastasis by promoting the mesenchymal-epithelial transition (MET) through the ERK/MAPK pathway, thus facilitating colonization of metastatic breast tumor cells.

Susceptibility of Human Oral Squamous Cell Carcinoma (OSCC) H103 and H376 cell lines to Retroviral OSKM mediated reprogramming

Although numbers of cancer cell lines have been shown to be successfully reprogrammed into induced pluripotent stem cells (iPSCs), reprogramming Oral Squamous Cell Carcinoma (OSCC) to pluripotency in relation to its cancer cell type and the expression pattern of pluripotent genes under later passage remain unexplored. In our study, we reprogrammed and characterised H103 and H376 oral squamous carcinoma cells using retroviral OSKM mediated method. Reprogrammed cells were characterized for their embryonic stem cells (ESCs) like morphology, pluripotent gene expression via quantitative real-time polymerase chain reaction (RT-qPCR), immunofluorescence staining, embryoid bodies (EB) formation and directed differentiation capacity. Reprogrammed H103 (Rep-H103) exhibited similar ESCs morphologies with flatten cells and clear borders on feeder layer. Reprogrammed H376 (Rep-H376) did not show ESCs morphologies but grow with a disorganized morphology. Critical pluripotency genes Oct4, Sox2 and Nanog were expressed higher in Rep-H103 against the parental counterpart from passage 5 to passage 10. As for Rep-H376, Nanog expression against its parental counterpart showed a significant decrease at passage 5 and although increased in passage 10, the level of expression was similar to the parental cells. Rep-H103 exhibited pluripotent signals (Oct4, Sox2, Nanog and Tra-1-60) and could form EB with the presence of three germ layers markers. Rep-H103 displayed differentiation capacity into adipocytes and osteocytes. The OSCC cell line H103 which was able to be reprogrammed into an iPSC like state showed high expression of Oct4, Sox2 and Nanog at late passage and may provide a potential iPSC model to study multi-stage oncogenesis in OSCC.

Controlling Stochasticity in Epithelial-Mesenchymal Transition Through Multiple Intermediate Cellular States

Epithelial-mesenchymal transition (EMT) is an instance of cellular plasticity that plays critical roles in development, regeneration and cancer progression. Recent studies indicate that the transition between epithelial and mesenchymal states is a multi-step and reversible process in which several intermediate phenotypes might coexist. These intermediate states correspond to various forms of stem-like cells in the EMT system, but the function of the multi-step transition or the multiple stem cell phenotypes is unclear. Here, we use mathematical models to show that multiple intermediate phenotypes in the EMT system help to attenuate the overall fluctuations of the cell population in terms of phenotypic compositions, thereby stabilizing a heterogeneous cell population in the EMT spectrum. We found that the ability of the system to attenuate noise on the intermediate states depends on the number of intermediate states, indicating the stem-cell population is more stable when it has more sub-states. Our study reveals a novel advantage of multiple intermediate EMT phenotypes in terms of systems design, and it sheds light on the general design principle of heterogeneous stem cell population.

Chemical Modulation of Cell Fate in Stem Cell Therapeutics and Regenerative Medicine

Regenerative medicine aims to repair and regenerate injured tissues and restore their impaired functions. Recent developments in stem cell biology have attracted significant interest in their applications in regenerative medicine. Chemical approaches using small molecules have yielded exciting results in induction and differentiation of pluripotent stem cells, lineage conversion of somatic cells, and ex vivo as well as in vivo modulation of adult stem cells. In this review, we discuss recent progress, new insights, and future challenges of the chemical approaches in stem cell biology and regenerative medicine.

A developmental framework for induced pluripotency

During development, cells transition from a pluripotent to a differentiated state, generating all the different types of cells in the body. Development is generally considered an irreversible process, meaning that a differentiated cell is thought to be unable to return to the pluripotent state. However, it is now possible to reprogram mature cells to pluripotency. It is generally thought that reprogramming is accomplished by reversing the natural developmental differentiation process, suggesting that the two mechanisms are closely related. Therefore, a detailed study of cell reprogramming has the potential to shed light on unexplained developmental mechanisms and, conversely, a better understanding of developmental differentiation can help improve cell reprogramming. However, fundamental differences between reprogramming processes and multi-lineage specification during early embryonic development have also been uncovered. In addition, there are multiple routes by which differentiated cells can re-enter the pluripotent state. In this Review, we discuss the connections and disparities between differentiation and reprogramming, and assess the degree to which reprogramming can be considered as a simple reversal of development.

The Epigenetic Reprogramming Roadmap in Generation of iPSCs from Somatic Cells

Reprogramming of somatic cells to induced pluripotent stem cells (iPSCs) is a comprehensive epigenetic process involving genome-wide modifications of histones and DNA methylation. This process is often incomplete, which subsequently affects iPSC reprogramming, pluripotency, and differentiation capacity. Here, we review the epigenetic changes with a focus on histone modification (methylation and acetylation) and DNA modification (methylation) during iPSC induction. We look at changes in specific epigenetic signatures, aberrations and epigenetic memory during reprogramming and small molecules influencing the epigenetic reprogramming of somatic cells. Finally, we discuss how to improve iPSC generation and pluripotency through epigenetic manipulations.

Emerging role of HMGB1 in fibrotic diseases

High-mobility group box 1 (HMGB1) is originally identified as a DNA-binding protein that functions as a structural co-factor critical for proper transcriptional regulation in somatic cells. Recent studies indicate that HMGB1 can be passively released from necrotic cells or actively secreted into the extracellular milieu under appropriate signal stimulation. Extracellular HMGB1 is a multifunctional cytokine that contributes to the process of infection, injury, inflammation, apoptosis, and immune responses by binding to specific cell-surface receptors. Recently, emerging studies indicate that HMGB1 is closely involved in fibrotic disorders including cystic fibrosis, liver fibrosis and pulmonary fibrosis, while HMGB1 signal inhibitions protect against the experimental models of fibrotic diseases. From a clinical perspective, HMGB1 represents a current challenge that can be exploited orchestrate reparative responses. This review focuses on the crucial role of HMGB1 in the pathogenesis of fibrotic diseases and inhibition of which may represent a promising clinical approach for treating tissue fibrosis.

Where cell fate conversions meet Chinese philosophy

Accumulating evidence indicates that the mesenchymal-epithelial transition (MET) and epithelial-mesenchymal transition (EMT) are basic mechanisms for cell fate conversion and may help us understand both physiologic and pathologic processes such as development and carcinogenesis. Here, we further suggest that mammalian cells fall into two grand divisions, mesenchymal or epithelial; interconversions between these two grand divisions through EMT/MET resonate with some ancient Chinese philosophic ideas.

Role of the microtubule-targeting drug vinflunine on cell-cell adhesions in bladder epithelial tumour cells

Background

Vinflunine (VFL) is a microtubule-targeting drug that suppresses microtubule dynamics, showing anti-metastatic properties both in vitro and in living cancer cells. An increasing body of evidence underlines the influence of the microtubules dynamics on the cadherin-dependent cell-cell adhesions. E-cadherin is a marker of epithelial-to-mesenchymal transition (EMT) and a tumour suppressor; its reduced levels in carcinoma are associated with poor prognosis. In this report, we investigate the role of VFL on cell-cell adhesions in bladder epithelial tumour cells.

Methods

Human bladder epithelial tumour cell lines HT1376, 5637, SW780, T24 and UMUC3 were used to analyse cadherin-dependent cell-cell adhesions under VFL treatment. VFL effect on growth inhibition was measured by using a MTT colorimetric cell viability assay. Western blot, immunofluorescence and transmission electron microscopy analyses were performed to assess the roles of VFL effect on cell-cell adhesions, epithelial-to-mesenchymal markers and apoptosis. The role of the proteasome in controlling cell-cell adhesion was studied using the proteasome inhibitor MG132.

Results

We show that VFL induces cell death in bladder cancer cells and activates epithelial differentiation of the remaining living cells, leading to an increase of E-cadherin-dependent cell-cell adhesion and a reduction of mesenchymal markers, such as N-cadherin or vimentin. Moreover, while E-cadherin is increased, the levels of Hakai, an E3 ubiquitin-ligase for E-cadherin, were significantly reduced in presence of VFL. In 5637, this reduction on Hakai expression was blocked by MG132 proteasome inhibitor, indicating that the proteasome pathway could be one of the molecular mechanisms involved in its degradation.

Conclusions

Our findings underscore a critical function for VFL in cell-cell adhesions of epithelial bladder tumour cells, suggesting a novel molecular mechanism by which VFL may impact upon EMT and metastasis.

Cell reprogramming into the pluripotent state using graphene based substrates

Graphene has been attracting considerable interest in the field of biomedical engineering because graphene and its derivatives are considered to be ideal platforms for supporting cell growth and differentiation. Here we report that graphene promotes the reprogramming of mouse somatic fibroblasts into induced pluripotent stem cells (iPSCs). We constructed a layer of graphene film on a glass substrate and characterized it as a monolayer using Raman spectroscopy. We found that the graphene substrate significantly improved cellular reprogramming efficiency by inducing mesenchymal-to-epithelial-transition (MET) which is known to affect H3K4me3 levels. Thus, our results reveal that a graphene substrate directly regulates dynamic epigenetic changes associated with reprogramming, providing an efficient tool for epigenetic pluripotent reprogramming.

Combining small molecules for cell reprogramming through an interatomic analysis

The knowledge available about the application and generation of induced pluripotent stem cells (iPSC) has grown since their discovery, and new techniques to enhance the reprogramming process have been described. Among the new approaches to induce iPSC that have gained great attention is the use of small molecules for reprogramming. The application of small molecules, unlike genetic manipulation, provides for control of the reprogramming process through the shifting of concentrations and the combination of different molecules. However, different researchers have reported the use of "reprogramming cocktails" with variable results and drug combinations. Thus, the proper combination of small molecules for successful and enhanced reprogramming is a matter for discussion. However, testing all potential drug combinations in different cell lineages is very costly and time-consuming. Therefore, in this article, we discuss the use of already employed molecules for iPSC generation, followed by the application of systems chemo-biology tools to create different data sets of protein-protein (PPI) and chemical-protein (CPI) interaction networks based on the knowledge of already used and new reprogramming cocktail combinations. We further analyzed the biological processes associated with PPI-CPI networks and provided new potential protein targets to be inhibited or expressed for stem cell reprogramming. In addition, we applied a new interference analysis to prospective targets that could negatively affect the classical pluripotency-associated factors (SOX2, NANOG, KLF4 and OCT4) and thus potentially improve reprogramming protocols.

Role of reflux-induced epithelial-mesenchymal transition in periprosthetic leakage after prosthetic voice rehabilitation

BACKGROUND

Gastroesophageal reflux (GER) contributes to periprosthetic leakage after prosthetic voice rehabilitation. However, underlying mechanisms are unclear, and markers predicting anti-reflux therapy response are missing.

METHODS

We assessed epithelial-mesenchymal transition in 148 consecutive biopsies from 44 patients with/without fistula enlargement under dual-probe pH monitoring before and after proton-pump inhibitor (PPI) therapy applying immunohistochemistry. Results were correlated with reflux intensity and clinical and histologic findings.

RESULTS

Epithelial-mesenchymal transition correlated with GER in all samples, and patients with fistula enlargement showed higher epithelial-mesenchymal transition scores. Contrary to patients without enlargement, epithelial-mesenchymal transition scores did not regress during therapy in this group. Furthermore, pretherapeutic epithelial-mesenchymal transition scores were lower in therapy responders than in nonresponders without reaching significance (p = .07).

CONCLUSION

We demonstrate that epithelial-mesenchymal transition correlates with severity of GER and presence of periprosthetic fistula enlargement in patients who underwent prosthetic voice rehabilitation, but epithelial-mesenchymal transition seems to be reversible upon PPI treatment in early stages only.

Role of the epithelial-mesenchymal transition in bladder cancer: from prognosis to therapeutic target

Bladder cancer (BC) is the second most common malignancy of urological organs. However, patients with non-muscle-invasive BC are at high risk of recurrence and progression into muscle-invasive BC, and the prognosis of patients with muscle-invasive BC is limited by the high rate of metastasis. The epithelial-mesenchymal transition (EMT) is characterized by loss of cell-to-cell adhesion and cell polarity and is closely associated with the invasion and metastasis of several cancers. Given the multifocality and high rates of relapse, progression, and metastasis of BC, the EMT is likely to participate in BC as well. Numerous factors associate with the EMT, and the key regulators of the EMT are E-cadherin, N-cadherin, Twist, Snail, Slug, Zeb-1, Zeb-2, vimentin, and microRNAs. This review focuses on the current concepts regarding the EMT in cancer and the evidence for involvement of the EMT in BC. Several potential EMT targets that may be useful in the treatment of BC are also described.

SSX2IP promotes metastasis and chemotherapeutic resistance of hepatocellular carcinoma

Background

Synovial sarcoma, X breakpoint 2 interacting protein (SSX2IP), which has been identified as an acute myeloid leukemia associated antigen, is a potential target for leukemia immunotherapy. In rodents, its homologous gene, ADIP, plays an important role in the regulation of cell adhesion and migration, underlying its potential role in promoting metastasis of other cancers.

Methods

To investigate the correlation between the expression level of SSX2IP and the clinicopathologic factors of hepatocellular carcinoma (HCC), 53 cases were studied by qPCR and statisted. To directly testing SSX2IP’s contribution to HCC in animal models, 45 nude mice were enrolled in peritoneal spreading and liver metastasis models. For the migration and invasion assays, cell culture experiments were performed using QCM^TM 24-Well Colorimetric Migration Assay Kit and Cell Invasion Assay Kit (Millipore). Moreover we examined the influence of SSX2IP overexpression on the chemosensitivity of hepatocellular carcinoma cells to two most common chemotherapy drugs (5-Fu and CDDP) using Cell counting kit-8 (CCK-8). The chemotherapeutic drugs sensitivity was evaluated by IC50 parameter.

Results

Statistical analysis of clinical cases revealed that the SSX2IP high expression group had inclinations towards larger tumor size, more tumor thrombus and shorter survival period, implying a strong correlation between the expression level of SSX2IP and HCC tumorigenesis. Consistently in abdominal cavity metastasis and liver metastasis models of immune-deficient mice, SSX2IP was able to promote the metastasis of hepatoma cells. At the cytological level, SSX2IP stimulates the wound healing, metastasis and invasion of hepatoma cells, and reduces the sensitivity of hepatoma cells to 5-Fu and CDDP.

Conclusions

Our results showed that SSX2IP promotes the development and metastasis of hepatocellular carcinoma and contributes to the drug resistance of hepatoma cells, suggesting that SSX2IP is expected to become a new diagnostic and prognostic marker and a new target of the treatment of hepatocellular carcinoma.

Induction of EMT-like response by BMP4 via up-regulation of lysyl oxidase is required for adipocyte lineage commitment

The developmental pathway that gives rise to mature adipocytes involves commitment and terminal differentiation. Our previous findings indicate that BMP4 (bone morphogenetic protein 4) induces nearly complete commitment of C3H10T1/2 pluripotent stem cells to the adipocyte lineage and knockdown of lysyl oxidase (Lox) disrupts this commitment process. Here, we found that an epithelial-mesenchymal transition (EMT)-like response is required for adipocyte lineage commitment and that Lox is indispensable for this process. When C3H10T1/2 cells were treated with BMP4, Vim and Cdh2 showed up-regulated expression while Cdh1 and Ocln were down-regulated along with enhanced cell migration, which are EMT-like responses. Silencing of Lox in BMP4-treated C3H10T1/2 cells induced a mesenchymal-epithelial transition (MET)-like response associated with the repression of mesenchymal markers, induction of epithelial markers and decreased cell migration. Importantly, blocking the EMT-like response by knocking down Cdh2 or over-expression of Cdh1 impairs adipocyte lineage commitment. EMT is regulated by distinct transcription factors such as Snai1, Snai2 and Twist. In this study, we also found that only Twist was down-regulated after Lox silencing in C3H10T1/2 cells treated with BMP4. This study provides new insights into adipocyte lineage commitment.

Role of Cripto-1 during epithelial-to-mesenchymal transition in development and cancer

Epithelial-to-mesenchymal transition (EMT) is a critical multistep process that converts epithelial cells to more motile and invasive mesenchymal cells, contributing to body patterning and morphogenesis during embryonic development. In addition, both epithelial plasticity and increased motility and invasiveness are essential for the branching morphogenesis that occurs during development of the mammary gland and during tumor formation, allowing cancer cells to escape from the primary tumor. Cripto-1, a member of the epidermal growth factor-Cripto-1/FRL-1/Cryptic (EGF/CFC) gene family, together with the transforming growth factor (TGF)-β family ligand Nodal, regulates both cell movement and EMT during embryonic development. During postnatal development, Cripto-1 regulates the branching morphogenesis of the mouse mammary gland and enhances both the invasive and migratory properties of mammary epithelial cells in vitro. Furthermore, transgenic mouse models have shown that Cripto-1 promotes the formation of mammary tumors that display properties of EMT, including the down-regulation of the cell surface adherens junctional protein E-cadherin and the up-regulation of mesenchymal markers, such as vimentin, N-cadherin, and Snail. Interestingly, Cripto-1 is enriched in a subpopulation of embryonal, melanoma, prostate, and pancreatic cancer cells that possess stem-like characteristics. Therefore, Cripto-1 may play a role during developmental EMT, and it may also be involved in the reprogramming of differentiated tumor cells into cancer stem cells through the induction of an EMT program.