Molecular signature and therapeutic perspective of the epithelial-to-mesenchymal transitions in epithelial cancers

An Analysis Regarding the Association Between DAZ Interacting Zinc Finger Protein 1 (DZIP1) and Colorectal Cancer (CRC)

Colorectal cancer (CRC) is the third most common malignant disease worldwide, and its incidence is increasing, but the molecular mechanisms of this disease are highly heterogeneous and still far from being fully understood. Increasing evidence suggests that fibrosis mediated by abnormal activation of fibroblasts based in the microenvironment is associated with a poor prognosis. However, the function and pathogenic mechanisms of fibroblasts in CRC remain unclear. Here, combining scrna-seq and clinical specimen data, DAZ Interacting Protein 1 (DZIP1) was found to be expressed on fibroblasts and cancer cells and positively correlated with stromal deposition. Importantly, pseudotime-series analysis showed that DZIP1 levels were up-regulated in malignant transformation of fibroblasts and experimentally confirmed that DZIP1 modulates activation of fibroblasts and promotes epithelial-mesenchymal transition (EMT) in tumor cells. Further studies showed that DZIP1 expressed by tumor cells also has a driving effect on EMT and contributes to the recruitment of more fibroblasts. A similar phenomenon was observed in xenografted nude mice. And it was confirmed in xenograft mice that downregulation of DZIP1 expression significantly delayed tumor formation and reduced tumor size in CRC cells. Taken together, our findings suggested that DZIP1 was a regulator of the CRC mesenchymal phenotype. The revelation of targeting DZIP1 provides a new avenue for CRC therapy.

Cancer stem cells: an insight into the development of metastatic tumors and therapy resistance

The term "cancer stem cells" (CSCs) refers to cancer cells that exhibit traits parallel to normal stem cells, namely the potential to give rise to every type of cell identified in a tumor microenvironment. It has been found that CSCs usually develops from other neoplastic cells or non-cancerous somatic cells by acquiring stemness and malignant characteristics through particular genetic modifications. A trivial number of CSCs, identified in solid and liquid cancer, can give rise to an entire tumor population with aggressive anticancer drug resistance, metastasis, and invasiveness. Besides, cancer stem cells manipulate their intrinsic and extrinsic features, regulate the metabolic pattern of the cell, adjust efflux-influx efficiency, modulate different signaling pathways, block apoptotic signals, and cause genetic and epigenetic alterations to retain their pluripotency and ability of self-renewal. Notably, to keep the cancer stem cells' ability to become malignant cells, mesenchymal stem cells, tumor-associated fibroblasts, immune cells, etc., interact with one another. Furthermore, CSCs are characterized by the expression of particular molecular markers that carry significant diagnostic and prognostic significance. Because of this, scientific research on CSCs is becoming increasingly imperative, intending to understand the traits and behavior of cancer stem cells and create more potent anticancer therapeutics to fight cancer at the CSC level. In this review, we aimed to elucidate the critical role of CSCs in the onset and spread of cancer and the characteristics of CSCs that promote severe resistance to targeted therapy.

miRNAs as potential game-changers in head and neck cancer: Future clinical and medicinal uses

Head and neck cancers (HNCs) are a group of heterogeneous tumors formed most frequently from epithelial cells of the larynx, lips, oropharynx, nasopharynx, and mouth. Numerous epigenetic components, including miRNAs, have been demonstrated to have an impact on HNCs characteristics like progression, angiogenesis, initiation, and resistance to therapeutic interventions. The miRNAs may control the production of numerous genes linked to HNCs pathogenesis. The roles that miRNAs play in angiogenesis, invasion, metastasis, cell cycle, proliferation, and apoptosis are responsible for this impact. The miRNAs also have an impact on crucial HNCs-related mechanistic networks like the WNT/β-catenin signaling, PTEN/Akt/mTOR pathway, TGFβ, and KRAS mutations. miRNAs may affect how the HNCs respond to treatments like radiation and chemotherapy in addition to pathophysiology. This review aims to demonstrate the relationship between miRNAs and HNCs with a particular emphasis on how miRNAs impact HNCs signaling networks.

Phospholipase C delta 1 inhibits WNT/β-catenin and EGFR-FAK-ERK signaling and is disrupted by promoter CpG methylation in renal cell carcinoma

BACKGROUND

PLCD1, located at 3p22, encodes an enzyme that mediates cellular metabolism and homeostasis, intracellular signal transduction and movement. PLCD1 plays a pivotal role in tumor suppression of several types of cancers; however, its expression and underlying molecular mechanisms in renal cell carcinoma (RCC) pathogenesis remain elusive.

METHODS

RT-PCR and Western blot were used to detect PLCD1 expression in RCC cell lines and normal tissues. Bisulfite treatment, MSP and BGS were utilized to explore the CpG methylation status of PLCD1 promoter. Online databases were analyzed for the association between PLCD1 expression/methylation and patient survival. In vitro experiments including CCK8, colony formation, wound-healing, transwell migration and invasion, immunofluorescence and flow cytometry assays were performed to evaluate tumor cell behavior. Luciferase assay and Western blot were used to examine effect of PLCD1 on WNT/β-catenin and EGFR-FAK-ERK signaling.

RESULTS

We found that PLCD1 was widely expressed in multiple adult normal tissues including kidney, but frequently downregulated or silenced in RCC due to its promoter CpG methylation. Restoration of PLCD1 expression inhibited the viability, migration and induced G2/M cell cycle arrest and apoptosis in RCC cells. PLCD1 restoration led to the inhibition of signaling activation of WNT/β-catenin and EGFR-FAK-ERK pathways, and the EMT program of RCC cells.

CONCLUSIONS

Our results demonstrate that PLCD1 is a potent tumor suppressor frequently inactivated by promoter methylation in RCC and exerts its tumor suppressive functions via suppressing WNT/β-catenin and EGFR-FAK-ERK signaling. These findings establish PLCD1 as a promising prognostic biomarker and treatment target for RCC.

HMMR promotes prostate cancer proliferation and metastasis via AURKA/mTORC2/E2F1 positive feedback loop

Although dysregulated HMMR is linked to prostate cancer (PCa) prognosis, the precise mechanisms remain unclear. Here, we sought to elucidate the role of HMMR in PCa progression as well as underlying mechanism. Herein, we found that upregulation of HMMR frequently observed in PCa samples and was associated with poor prognosis. Additionally, HMMR significantly promoted PCa proliferation and metastasis through gain- and loss-of function approaches in vitro and in vivo. Mechanistically, HMMR may interact with AURKA and elevated AURKA protein level through inhibiting ubiquitination-mediated degradation, which subsequently activated mTORC2/AKT pathway to ensure the reinforcement of PCa progression. Moreover, upregulated E2F1 caused from sustained activation of mTORC2/AKT pathway in turn function as transcription factor to promote HMMR transcription, thereby forming a positive feedback loop to trigger PCa progression. Importantly, administration of the mTOR inhibitor partially antagonised HMMR-mediated PCa progression in vivo. In summary, we not only reveal a novel possible post-translation mechanism mediated by HMMR involved in AURKA regulation, but also describe a positive feedback loop that contributes to PCa deterioration, suggesting HMMR may serve as a potential promising therapeutic target in PCa.

Neogenin suppresses tumor progression and metastasis via inhibiting Merlin/YAP signaling

From in situ growth to invasive dissemination is the most lethal attribute of various tumor types. This transition is majorly mediated by the dynamic interplay between two cancer hallmarks, EMT and cell cycle. In this study, we applied nonlinear association analysis in 33 cancer types and found that most signaling receptors simultaneously associating with EMT and cell cycle are potential tumor suppressors. Here we find that a top co-associated receptor, Neogenin (NEO1), inhibits colorectal cancer (CRC) and Glioma in situ growth and metastasis by forming a complex with Merlin (NF2), and subsequent simultaneous promoting the phosphorylation of YAP. Furthermore, Neogenin protein level is associated with good prognosis and correlates with Merlin status in CRC and Glioma. Collectively, our results define Neogenin as a tumor suppressor in CRC and Glioma that acts by restricting oncogenic signaling by the Merlin-YAP pathway, and suggest Neogenin as a candidate therapeutic agent for CRC and Glioma.

In-silico study of asymmetric remodeling of tumors in response to external biochemical stimuli

Among different hallmarks of cancer, understanding biomechanics of tumor growth and remodeling benefits the most from the theoretical framework of continuum mechanics. Tumor remodeling initiates when cancer cells seek new homeostasis in response to the microenvironmental stimuli. Cells within a growing tumor are capable to remodel their inter- and intra-connections and become more mobile to achieve a new homeostasis. This mobility enables the tumor to undergo large deformation. In this work, we studied the remodeling of homogeneous tumors, at their early stage of growth, in the context of continuum mechanics. We developed an evolution law for the remodeling-associated deformation which correlates the remodeling to a characteristic tensor of external stimuli. The asymmetric remodeling and the induced mechanical stresses were analyzed for different types of biochemical distributions. To experimentally investigate the model, we studied the remodeling of human glioblastoma (hGB) tumoroids in response to the gradient of nutrients. Using a tumoroid-on-a-chip platform, the degree of remodeling was estimated for the ellipsoidal tumoroids over time. It was observed that higher gradient of nutrients induces higher degree of ellipticity suggesting that the gradient of nutrient is a characteristic property of nutrient distribution that derives the remodeling. We also showed that remodeling gives rise to heterogeneity in cell distribution forming circumferentially aligned cells within the tumors. Compared to the existing studies on tumor growth, our work provides a biomechanical module that relates the remodeling to biochemical stimuli, and allows for large deformation. It also includes experimental component, a necessary but challenging step, that connects the theory and reality to evaluate the practicability of the model.

LncRNA MEG3 attenuates the malignancy of retinoblastoma cells through inactivating PI3K /Akt/mTOR signaling pathway

Retinoblastoma (RB) is the most common neoplasm found in the eye of children. There are increasing interests to develop targeted gene therapy for this disease. This study was performed to investigate the impact of long non-coding RNA (lncRNA) MEG3 on the biological features of RB cells. Vector overexpressing MEG3 was constructed and introduced into two RB cell lines. Transfected RB cells were assessed for proliferation, apoptosis, migration ability, expression levels of important genes in the PI3K/Akt/mTOR signaling pathway using qRT-PCR and Western blot analysis. Xenograft mouse models were constructed to determine the tumorigenicity of RB cells overexpressing MEG3. MEG3 mRNA level was significantly lower in RB cells than in non-cancer cells (p < 0.01). Overexpressing MEG3 resulted in significant reduction in cell proliferation (p < 0.05), migration (p < 0.01) and significant increase in apoptosis (p < 0.01). After overexpressing MEG3, p-PI3K, p-Akt and p-mTOR levels were significantly downregulated (p < 0.01). Furthermore, in the xenograft model, RB cells overexpressing MEG3 generated significantly smaller tumors as compared to RB cells that did not overexpress MEG3 (p < 0.05). Our data suggest that MEG3 increases apoptosis and reduces tumorigenicity of RB cells through inactivating the PI3K/Akt/mTOR pathway. Therefore, MEG3 could be further investigated as a potential new therapeutic agent and target for RB therapy.

CMTM6 as a candidate risk gene for cervical cancer: Comprehensive bioinformatics study

Background: CKLF like MARVEL transmembrane domain containing 6 (CMTM6) is an important programmed cell death 1 ligand 1 regulator (PD-L1). CMTM6 was reported as an important regulator of PD-L1 by promoting PD-L1 expression in tumor cells against T cells. However, the function of CMTM6 in cervical cancer is not well characterized. In addition, the role of CMTM6 in the induction of epithelial-mesenchymal transition (EMT) in the context of cervical cancer is unknown. Methods: In this study, we evaluated the role of CMTM6, including gene expression analysis, miRNA target regulation, and methylation characteristic, using multiple bioinformatics tools based on The Cancer Genome Atlas (TCGA) database. The expression of CMTM6 in cervical cancer tissues and non-cancerous adjacent tissues was assessed using immunohistochemistry. In vitro and in vivo function experiments were performed to explore the effects of CMTM6 on growth and metastasis of cervical cancer. Results: Human cervical cancer tissues showed higher expression of CMTM6 than the adjacent non-cancerous tissues. In vitro assays showed that CMTM6 promoted cervical cancer cell invasion, migration, proliferation, and epithelial-mesenchymal transition via activation of mitogen-activated protein kinase (MAPK) c-jun N-terminal kinase (JNK)/p38 signaling pathway. We identified transcription factors (TFs), miRNAs, and immune cells that may interact with CMTM6. Conclusion: These results indicate that CMTM6 is a potential therapeutic target in the context of cervical cancer.

HOTAIR/miR-1277-5p/ZEB1 axis mediates hypoxia-induced oxaliplatin resistance via regulating epithelial-mesenchymal transition in colorectal cancer

The hypoxic microenvironment contributes to the chemoresistance of many malignant tumors including colorectal cancer (CRC). Accumulating studies have indicated that long non-coding RNAs (lncRNAs) play important roles in chemotherapy resistance. In this study, we aimed to determine the effect of lncRNAs in hypoxia-mediated resistance in CRC and its potential mechanism. Here, we discovered that hypoxia-induced oxaliplatin resistance and HOX transcript antisense RNA (HOTAIR) expression was increased in hypoxia-treated CRC cell lines and CRC tumors. Knockdown of HOTAIR by siRNA reduced the viability and proliferation of CRC cells treated with oxaliplatin and reversed hypoxia-induced resistance. Mechanically, we found that HOTAIR modulates zinc finger E-box binding homeobox 1 (ZEB1) expression by negative regulations of miR-1277-5p. When miR-1277-5p was silenced, knockdown of HOTAIR was unable to reduce the oxaliplatin resistance in CRC cells. In mouse models of CRC, HOTAIR knockdown markedly inhibited the tumor growth when treated with oxaliplatin. Thus, HOTAIR/miR-1277-5p/ZEB1 axis appears a promising therapeutic target for improving the oxaliplatin efficacy in CRC.

CXCR4 knockdown enhances sensitivity of paclitaxel via the PI3K/Akt/mTOR pathway in ovarian carcinoma

Epithelial ovarian cancer (EOC) is the deadliest gynecological malignancy. EOC control remains difficult, and EOC patients show poor prognosis regarding metastasis and chemotherapy resistance. The aim of this study was to estimate the effect of CXCR4 knockdown-mediated reduction of cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) stemness and enhancement of chemotherapy sensitivity in EOC. Mechanisms contributing to these effects were also explored. Our data showed distinct contribution of CXCR4 overexpression by dependent PI3K/Akt/mTOR signaling pathway in EOC development. CXCR4 knockdown resulted in a reduction in CSCs and EMT formation and enhancement of chemotherapy sensitivity in tumor cells, which was further advanced by blocking CXCR4-PI3K/Akt/mTOR signaling. This study also documented the critical role of silencing CXCR4 in sensitizing ovarian CSCs to chemotherapy. Thus, targeting CXCR4 to suppress EOC progression, specifically in combination with paclitaxel (PTX) treatment, may have clinical application value.

Metabolomics and EMT Markers of Breast Cancer: A Crosstalk and Future Perspective

Cancer cells undergo transient EMT and MET phenomena or vice versa, along with the parallel interplay of various markers, often correlated as the determining factor in decoding metabolic profiling of breast cancers. Moreover, various cancer signaling pathways and metabolic changes occurring in breast cancer cells modulate the expression of such markers to varying extents. The existing research completed so far considers the expression of such markers as determinants regulating the invasiveness and survival of breast cancer cells. Therefore, this manuscript is crosstalk among the expression levels of such markers and their correlation in regulating the aggressiveness and invasiveness of breast cancer. We also attempted to cover the possible EMT-based metabolic targets to retard migration and invasion of breast cancer.

The emerging roles of Gα12/13 proteins on the hallmarks of cancer in solid tumors

G12 proteins comprise a subfamily of G-alpha subunits of heterotrimeric GTP-binding proteins (G proteins) that link specific cell surface G protein-coupled receptors (GPCRs) to downstream signaling molecules and play important roles in human physiology. The G12 subfamily contains two family members: Gα12 and Gα13 (encoded by the GNA12 and GNA13 genes, respectively) and, as with all G proteins, their activity is regulated by their ability to bind to guanine nucleotides. Increased expression of both Gα12 and Gα13, and their enhanced signaling, has been associated with tumorigenesis and tumor progression of multiple cancer types over the past decade. Despite these strong associations, Gα12/13 proteins are underappreciated in the field of cancer. As our understanding of G protein involvement in oncogenic signaling has evolved, it has become clear that Gα12/13 signaling is pleotropic and activates specific downstream effectors in different tumor types. Further, the expression of Gα12/13 proteins is regulated through a series of transcriptional and post-transcriptional mechanisms, several of which are frequently deregulated in cancer. With the ever-increasing understanding of tumorigenic processes driven by Gα12/13 proteins, it is becoming clear that targeting Gα12/13 signaling in a context-specific manner could provide a new strategy to improve therapeutic outcomes in a number of solid tumors. In this review, we detail how Gα12/13 proteins, which were first discovered as proto-oncogenes, are now known to drive several "classical" hallmarks, and also play important roles in the "emerging" hallmarks, of cancer.

Transcription phenotype of circulating tumor cells in non-metastatic breast cancer

The presented research is relevant, as breast cancer is the most commonly diagnosed cancer in the female population worldwide, with the exception of skin cancer. The aim of this article is to study the transcription phenotype of circulating tumor cells in non-metastatic breast cancer. The transcriptional phenotype of circulating tumor cells (CTCs) was studied using real-time polymerase chain reaction (PCR). Three-year OS was 79.2, and 90.8 without the expression with p Log-Rank=0.04. Independent prognostic factors for the recurrence of disease include the presence of CTCs expressing BIRC5 genes and ABC transporter genes in the peripheral blood before the start of special treatment for resectable breast cancer, as well as the preservation of CTCs per se after completion of special anticancer therapy. In patients with breast cancer stage I-IIIC, circulating tumor cells before special treatment have significant heterogeneity, manifested by a different transcriptional phenotype, including both actively growing and stem tumor cells, and cells at the epithelial-to-mesenchymal transition.

Inflammatory Components of the Thyroid Cancer Microenvironment: An Avenue for Identification of Novel Biomarkers

The incidence of thyroid cancer in the United States is on the rise with an appreciably high disease recurrence rate of 20-30%. Anaplastic thyroid cancer (ATC), although rare in occurrence, is an aggressive form of cancer with limited treatment options and bleak cure rates. This chapter uses discussions of in vitro models that are representative of papillary, anaplastic, and follicular thyroid cancer to evaluate the crosstalk between specific cells of the tumor microenvironment (TME), which serves as a highly heterogeneous realm of signaling cascades and metabolism that are associated with tumorigenesis. The cellular constituents of the TME carry out varying characteristic immunomodulatory functions that are discussed throughout this chapter. The aforementioned cell types include cancer-associated fibroblasts (CAFs), endothelial cells (ECs), and cancer stem cells (CSCs), as well as specific immune cells, including natural killer (NK) cells, dendritic cells (DCs), mast cells, T regulatory (Treg) cells, CD8+ T cells, and tumor-associated macrophages (TAMs). TAM-mediated inflammation is associated with a poor prognosis of thyroid cancer, and the molecular basis of the cellular crosstalk between macrophages and thyroid cancer cells with respect to inducing a metastatic phenotype is not yet known. The dynamic nature of the physiological transition to pathological metastatic phenotypes when establishing the TME encompasses a wide range of characteristics that are further explored within this chapter, including the roles of somatic mutations and epigenetic alterations that drive the genetic heterogeneity of cancer cells, allowing for selective advantages that aid in their proliferation. Induction of these proliferating cells is typically accomplished through inflammatory induction, whereby chronic inflammation sets up a constant physiological state of inflammatory cell recruitment. The secretions of these inflammatory cells can alter the genetic makeup of proliferating cells, which can in turn, promote tumor growth.This chapter also presents an in-depth analysis of molecular interactions within the TME, including secretory cytokines and exosomes. Since the exosomal cargo of a cell is a reflection and fingerprint of the originating parental cells, the profiling of exosomal miRNA derived from thyroid cancer cells and macrophages in the TME may serve as an important step in biomarker discovery. Identification of a distinct set of tumor suppressive miRNAs downregulated in ATC-secreted exosomes indicates their role in the regulation of tumor suppressive genes that may increase the metastatic propensity of ATC. Additionally, the high expression of pro-inflammatory cytokines in studies looking at thyroid cancer and activated macrophage conditioned media suggests the existence of an inflammatory TME in thyroid cancer. New findings are suggestive of the presence of a metastatic niche in ATC tissues that is influenced by thyroid tumor microenvironment secretome-induced epithelial to mesenchymal transition (EMT), mediated by a reciprocal interaction between the pro-inflammatory M1 macrophages and the thyroid cancer cells. Thus, targeting the metastatic thyroid carcinoma microenvironment could offer potential therapeutic benefits and should be explored further in preclinical and translational models of human metastatic thyroid cancer.

Disruption of Cell-Cell Communication in Anaplastic Thyroid Cancer as an Immunotherapeutic Opportunity

Thyroid cancer incidence is increasing at an alarming rate, almost tripling every decade. About 44,280 new cases of thyroid cancer (12,150 in men and 32,130 in women) are estimated to be diagnosed in 2021, with an estimated death toll of around 2200. Although most thyroid tumors are treatable and associated with a favorable outcome, anaplastic thyroid cancer (ATC) is extremely aggressive with a grim prognosis of 6-9 months post-diagnosis. A large contributing factor to this aggressive nature is that ATC is completely refractory to mainstream therapies. Analysis of the tumor microenvironment (TME) associated with ATC can relay insight to the pathological realm that encompasses tumors and aids in cancer progression and proliferation. The TME is defined as a complex niche that surrounds a tumor and involves a plethora of cellular components whose secretions can modulate the environment in order to favor tumor progression. The cellular heterogeneity of the TME contributes to its dynamic function due to the presence of both immune and nonimmune resident, infiltrating, and interacting cell types. Associated immune cells discussed in this chapter include macrophages, dendritic cells (DCs), natural killer (NK) cells, and tumor-infiltrating lymphocytes (TILs). Nonimmune cells also play a role in the establishment and proliferation of the TME, including neuroendocrine (NE) cells, adipocytes, endothelial cells (ECs), mesenchymal stem cells (MSCs), and fibroblasts. The dynamic nature of the TME contributes greatly to cancer progression.Recent work has found ATC tissues to be defined by a T cell-inflamed "hot" tumor immune microenvironment (TIME) as evidenced by presence of CD3+ and CD8+ T cells. These tumor types are amenable to immune checkpoint blockade (ICB) therapy. This therapeutic avenue, as of 2021, has remained unexplored in ATC. New studies should seek to explore the therapeutic feasibility of a combination therapy, through the use of a small molecule inhibitor with ICB in ATC. Screening of in vitro model systems representative of papillary, anaplastic, and follicular thyroid cancer explored the expression of 29 immune checkpoint molecules. There are higher expressions of HVEM, BTLA, and CD160 in ATC cell lines when compared to the other TC subtypes. The expression level of HVEM was more than 30-fold higher in ATC compared to the others, on average. HVEM is a member of tumor necrosis factor (TNF) receptor superfamily, which acts as a bidirectional switch through interaction with BTLA, CD160, and LIGHT, in a cis or trans manner. Given the T cell-inflamed hot TIME in ATC, expression of HVEM on tumor cells was suggestive of a possibility for complex crosstalk of HVEM with inflammatory cytokines. Altogether, there is emerging evidence of a T cell-inflamed TIME in ATC along with the expression of immune checkpoint proteins HVEM, BTLA, and CD160 in ATC. This can open doors for combination therapies using small molecule inhibitors targeting downstream effectors of MAPK pathway and antagonistic antibodies targeting the HVEM/BTLA axis as a potentially viable therapeutic avenue for ATC patients. With this being stated, the development of adaptive resistance to targeted therapies is inevitable; therefore, using a combination therapy that targets the TIME can serve as a preemptive tactic against the characteristic therapeutic resistance that is seen in ATC. The dynamic nature of the TME, including the immune cells, nonimmune cells, and acellular components, can serve as viable targets for combination therapy in ATC. Understanding the complex interactions of these associated cells and the paradigm in which their secretions and components can serve as immunomodulators are critical points of understanding when trying to develop therapeutics specifically tailored for the anaplastic thyroid carcinoma microenvironment.

Aloe-emodin inhibits the proliferation, migration, and invasion of melanoma cells via inactivation of the Wnt/beta-catenin signaling pathway

BACKGROUND

Aloe-emodin is reported as a potential cancer therapeutic agent due to its inhibition of the proliferation, migration, and invasion of cancer cells. This study aimed to confirm the effects of aloe-emodin on the progression of melanoma and identify the underlying molecular mechanisms.

METHODS

The effects of aloe-emodin treatment (concentrations ranging from 0 to 25 µg, 48 h) on proliferation, apoptosis, distribution of cell cycle, migration, and invasion were detected by performing Cell Counting Kit-8 (CCK-8) assay, colony formation assay, flow cytometry, wound healing assay, and Transwell invasion experiments. Rescue experiments were carried out by overexpression of β-catenin to verify the role of β-catenin in the inhibition of melanoma by aloe-emodin. The analysis was carried out at the animal level by constructing tumor-bearing nude mice model.

RESULTS

The results showed that aloe-emodin prominently reduced the proliferation, migration, and invasion of melanoma cells. Additionally, it was found that aloe-emodin significantly enhanced the cell apoptosis and induced G2 phase arrest of melanoma cells via enhancing the expressions of cleaved-caspase3, bax, and reducing cyclinD1, c-myc, and bcl-2. In addition, aloe-emodin could also inhibit Wnt3a levels, and promote GSK3-beta and beta-catenin phosphorylation. In vivo experiments also showed that overexpression of beta-catenin reversed the effects of aloe-emodin on tumor growth.

CONCLUSIONS

In conclusion, our findings indicated that aloe-emodin might prominently inhibit the tumor growth and metastasis of melanoma via the Wnt/beta-catenin signaling pathway in vitro. Therefore, aloe-emodin may serve as a potential drug for the clinical treatment of melanoma.

Single-Cell Analyses Reveal Mechanisms of Cancer Stem Cell Maintenance and Epithelial-Mesenchymal Transition in Recurrent Bladder Cancer

PURPOSE

Bladder cancer treatment remains a major clinical challenge due to therapy resistance and a high recurrence rate. Profiling intratumor heterogeneity can reveal the molecular mechanism of bladder cancer recurrence.

EXPERIMENTAL DESIGN

Here, we performed single-cell RNA sequencing and Assay for Transposase-Accessible Chromatin using sequencing (ATAC-seq) on tumors from 13 patients with low recurrence risk, high recurrence risk, and recurrent bladder cancer.

RESULTS

Our study generated a comprehensive cancer-cell atlas consisting of 54,971 single cells and identified distinct cell subpopulations. We found that the cancer stem-cell subpopulation is enriched during bladder cancer recurrence with elevated expression of EZH2. We further defined a subpopulation-specific molecular mechanism whereby EZH2 maintains H3K27me3-mediated repression of the NCAM1 gene, thereby inactivating the cell invasive and stemness transcriptional program. Furthermore, taking advantage of this large single-cell dataset, we elucidated the spectrum of epithelial-mesenchymal transition (EMT) in clinical samples and revealed distinct EMT features associated with bladder cancer subtypes. We identified that TCF7 promotes EMT in corroboration with single-cell ATAC with high-throughput sequencing (scATAC-seq) analysis. Additionally, we constructed regulatory networks specific to recurrent bladder cancer.

CONCLUSIONS

Our study and analytic approaches herein provide a rich resource for the further study of cancer stem cells and EMT in the bladder cancer research field.

MALT1 is a Targetable Driver of Epithelial-to-Mesenchymal Transition in Claudin-low, Triple-Negative Breast Cancer

MALT1 is the effector protein of the CARMA/Bcl10/MALT1 (CBM) signalosome, a multi-protein complex that drives pro-inflammatory signaling pathways downstream of a diverse set of receptors. While CBM activity is best known for its role in immune cells, emerging evidence suggests that it plays a key role in the pathogenesis of solid tumors, where it can be activated by selected G protein-coupled receptors (GPCRs). Here, we demonstrated that overexpression of GPCRs implicated in breast cancer pathogenesis, specifically the receptors for Angiotensin II and thrombin (AT1R and PAR1), drove a strong epithelial-to-mesenchymal transition (EMT) program in breast cancer cells that is characteristic of claudin-low, triple-negative breast cancer (TNBC). In concert, MALT1 was activated in these cells and contributed to the dramatic EMT phenotypic changes through regulation of master EMT transcription factors including Snail and ZEB1. Importantly, blocking MALT1 signaling, through either siRNA-mediated depletion of MALT1 protein or pharmacologic inhibition of its activity, was effective at partially reversing the molecular and phenotypic indicators of EMT. Treatment of mice with mepazine, a pharmacologic MALT1 inhibitor, reduced growth of PAR1+, MDA-MB-231 xenografts and had an even more dramatic effect in reducing the burden of metastatic disease. These findings highlight MALT1 as an attractive therapeutic target for claudin-low TNBCs harboring overexpression of one or more selected GPCRs. Implications: This study nominates a GPCR/MALT1 signaling axis as a pathway that can be pharmaceutically targeted to abrogate EMT and metastatic progression in TNBC, an aggressive form of breast cancer that currently lacks targeted therapies.

Cross-Talk of Focal Adhesion-Related Gene Defines Prognosis and the Immune Microenvironment in Gastric Cancer

Background: Focal adhesion, as the intermediary between tumor cells and extracellular matrix communication, plays a variety of roles in tumor invasion, migration, and drug resistance. However, the potential role of focal adhesion-related genes in the microenvironment, immune cell infiltration, and drug sensitivity of gastric cancer (GC) has not yet been revealed.

Methods: The genetic and transcriptional perspectives of focal adhesion-related genes were systematically analyzed. From a genetic perspective, the focal adhesion index (FAI) was constructed based on 18 prognosis-related focus adhesion-related genes to evaluate the immune microenvironment and drug sensitivity. Then three prognosis-related genes were used for consistent clustering to identify GC subtypes. Finally, use FLT1, EGF, COL5A2, and M2 macrophages to develop risk signatures, and establish a nomogram together with clinicopathological characteristics.

Results: Mutations in the focal adhesion-related gene affect the survival time and clinical characteristics of GC patients. FAI has been associated with a shorter survival time, immune signaling pathways, M2 macrophage infiltration, epithelial-mesenchymal transition (EMT) signaling, and diffuse type of GC. FAI recognizes ALK, cell cycle, and BMX signaling pathways inhibitors as sensitive agents for the treatment of GC. FLT1, EGF, and COL5A2 may distinguish GC subtypes. The established risk signature is of great significance to the prognostic evaluation of GC based on FLT1, EGF, and COL5A2 and M2 macrophage expression.

Conclusion: The focal adhesion-related gene is a potential biomarker for the evaluation of the immune microenvironment and prognosis. This work emphasizes the potential impact of the focal adhesion pathway in GC therapy and highlights its guiding role in prognostic evaluation.

Lipid droplets as metabolic determinants for stemness and chemoresistance in cancer

Previously regarded as simple fat storage particles, new evidence suggests that lipid droplets (LDs) are dynamic and functional organelles involved in key cellular processes such as membrane biosynthesis, lipid metabolism, cell signalling and inflammation. Indeed, an increased LD content is one of the most apparent features resulting from lipid metabolism reprogramming necessary to support the basic functions of cancer cells. LDs have been associated to different cellular processes involved in cancer progression and aggressiveness, such as tumorigenicity, invasion and metastasis, as well as chemoresistance. Interestingly, all of these processes are controlled by a subpopulation of highly aggressive tumoral cells named cancer stem cells (CSCs), suggesting that LDs may be fundamental elements for stemness in cancer. Considering the key role of CSCs on chemoresistance and disease relapse, main factors of therapy failure, the design of novel therapeutic approaches targeting these cells may be the only chance for long-term survival in cancer patients. In this sense, their biology and functional properties render LDs excellent candidates for target discovery and design of combined therapeutic strategies. In this review, we summarise the current knowledge identifying LDs and CSCs as main contributors to cancer aggressiveness, metastasis and chemoresistance.

Silent information regulator 1 suppresses epithelial-to-mesenchymal transition in lung cancer cells via its regulation of mitochondria status

AIMS

Silent information regulator 1 (SIRT1) is a NAD+-dependent protein-modifying enzyme involved in regulating gene expression, DNA damage repair, cell metabolism, and mitochondrial functions. Given that it acts as both a tumor promoter and suppressor, the complex mechanisms underlying SIRT1 signaling in cancer remain controversial. Epithelial-to-mesenchymal transition (EMT) plays a key role in the progression of carcinogenesis and tumors metastasis. Studies have shown that mitochondrial defects are critical in EMT process, and SIRT1 is found to regulate the generation and energy metabolism of mitochondria. Here, we elucidate a novel mechanism by which SIRT1 affects EMT in lung cancer cells via its regulation on mitochondria.

MAIN METHODS

SIRT1 signaling was detected in TGF-β1-induced EMT and was found to regulate mitochondria status, including mitochondrial biogenesis-related protein levels as detected by western blotting, mitochondrial structure observed by transmission electron microscopy, and respiratory functions analyzed by a respiration capacity assay. The effects of modulating SIRT1 expression on EMT and migration of lung cancer cells or normal cells were evaluated by in vitro and in vivo models.

KEY FINDINGS

We found that the regulation of SIRT1 signaling on the biogenesis or functions of mitochondria was critical to EMT. Overexpression of SIRT1 reduced EMT or metastasis potential of lung cancer cells by improving the quantity and quality of mitochondria, whereas silencing SIRT1 promote EMT in cancer cells, even in normal cells by disturbing mitochondria status.

SIGNIFICANCE

Consequently, SIRT1 is an attractive therapeutic target for reversing EMT or tumor metastasis.

Cancer drug resistance induced by EMT: novel therapeutic strategies

Over the last decade, important clinical benefits have been achieved in cancer patients by using drug-targeting strategies. Nevertheless, drug resistance is still a major problem in most cancer therapies. Epithelial-mesenchymal plasticity (EMP) and tumour microenvironment have been described as limiting factors for effective treatment in many cancer types. Moreover, epithelial-to-mesenchymal transition (EMT) has also been associated with therapy resistance in many different preclinical models, although limited evidence has been obtained from clinical studies and clinical samples. In this review, we particularly deepen into the mechanisms of which intermediate epithelial/mesenchymal (E/M) states and its interconnection to microenvironment influence therapy resistance. We also describe how the use of bioinformatics and pharmacogenomics will help to figure out the biological impact of the EMT on drug resistance and to develop novel pharmacological approaches in the future.

Tumor budding as a predictive marker for 5-fluorouracil response in adjuvant-treated stage III colorectal cancer

BACKGROUND

Tumor budding (TB) has been described as an adverse prognostic marker for operable colorectal cancer (CRC); however, a limited number of studies have demonstrated the prognostic significance of TB in patients with drug therapy. This study was conducted to determine the predictive power of TB in stage III CRC patients who received adjuvant chemotherapy.

METHODS

We retrospectively collected clinicopathological data including TB of 237 stage III colorectal cancer patients at Hiroshima University Hospital between July 1, 2006 and June 31, 2019. Differential disease-free survival (DFS) was investigated according to TB status.

RESULTS

This study included 237 patients with a median age of 67 years, comprising patients who underwent surgery alone (n = 65), 5-fluorouracil (5-FU) monotherapy (n = 129), and oxaliplatin-based chemotherapy (n = 43). Overall, 81 patients developed disease recurrence, and 33 patients died of cancer-related causes. The TB status was categorized into two groups: 99 with low budding (< 5 buds) and 138 with high budding (≥ 5 buds). Overall, the low budding cases demonstrated significantly better DFS. In the 5-FU monotherapy group, low-risk patients (T1, T2, or T3 and N1) with low budding showed a remarkably higher 3-year DFS (91%) compared to high budding (55%).

CONCLUSION

Our results indicate that TB could play a subsidiary role in selecting patients who could maintain a favorable prognosis with 5-FU monotherapy in stage III CRC.

Comparison of Snail1, ZEB1, E-Cadherin Expression Levels in HPV-Induced Cervical Cancer

Background:

Molecular profiling techniques are the rapid detection of biomarkers in the human papillomavirus (HPV) infected cells. We aimed to measure the expression level of three cell factors including Snail1, ZEB-1, and E-cadherin in cervical cancer (CC), precancerous and healthy samples, simultaneously, to find potential biomarkers.

Methods:

The expression level of the mentioned cell factors were investigated in 72 CC patients, precancerous patients, and healthy controls by using Real-Time PCR.

Results:

The results demonstrated a significant reduction in the expression level of E-cadherin in cancer and precancerous cases than that in healthy cases; whereas the expression level of ZEB-1 and Snail1 were upregulated in cancer and precancerous samples. The receiver operating characteristic (ROC) analyses shows the highest AUC value emerged for Snail1: 1(95% CI: 1-1) in comparing CC and healthy groups with a sensitivity of 100.0 % and specificity of 100.0%.

Conclusion:

The molecular biomarker Snail1 may be helpful to early diagnosis and prognosis of CC in the HPV-infected human populations. Considering the increased expression level of Snail1 in cancer and precancerous tissue compared to healthy tissue as well as the area under the ROC curve, Snail1 can be used for early detection of CC.

Metaplastic breast cancer: an old histotype but a current therapeutic problem

Metaplastic breast cancer (MPBC) is a rare and aggressive tumor type in great need of satisfactory therapies. Although most cases of MPBC are 'triple negative', they are nonetheless related to worse outcomes compared with other triple-negative invasive tumors. MPBC presents high levels of genetic and molecular heterogeneity, suggesting that novel targeted therapies can be exploited. Overexpression of PD-L1 and high levels of tumor-infiltrating lymphocytes have also been observed in these tumors, suggesting a role for immunotherapy. We present an updated literature revision on clinical, histopathological and molecular features of MPBC and their significance to prognosis and therapy options. We discuss emerging efforts to improve and personalize prognostic and therapeutic approaches, exploiting the molecular signature of MPBC with targeted therapies and immunotherapies.

Notch Signaling Pathway in Pancreatobiliary Tumors

Background and Objectives: The Notch signaling pathway plays an important role both in the development of the ductal systems of the pancreas and the bile ducts as well as in cancer development and progression. The aim of this study was to examine the expression of central proteins of the Notch signaling pathway in pancreatobiliary tumors and its influence on patient survival. Materials and Methods: We compared the receptors (Notch1, Notch4), activating splicing factors (ADAM17), and target genes (HES1) of the Notch pathway and progenitor cell markers with relevance for the Notch signaling pathway (CD44, MSI1) between pancreatic adenocarcinomas (PDAC, n = 14), intrahepatic cholangiocarcinoma (iCC, n = 24), and extrahepatic cholangiocarcinoma (eCC, n = 22) cholangiocarcinomas via immunohistochemistry and ImageJ software-assisted analysis. An Immunohistochemistry (IHC)-score was determined by the percentage and intensity of stained (positive) cells (scale 0–7) and normal and malignant tissue was compared. In the IHC results, patients’ (gender, age) and tumor (TNM Classification of Malignant Tumors, Union Internationale contre le Cancer (UICC) stages, grading, and lymphangitic carcinomatosa) characteristics were correlated to patient survival. Results: For eCC, the expression of CD44 (p = 0.043, IHC-score 3.94 vs. 3.54) and for iCC, the expression of CD44 (p = 0.026, IHC-score 4.04 vs. 3.48) and Notch1 (p < 0.001, IHC-score 2.87 vs. 1.78) was significantly higher in the tumor compared to non-malignant tissue. For PDAC, the expression of ADAM17 (p = 0.008, IHC-score 3.43 vs. 1.73), CD44 (p = 0.012, IHC-score 3.64 vs. 2.27), Notch1 (p = 0.012, IHC-score 2.21 vs. 0.64), and Notch4 (p = 0.008, IHC-score 2.86 vs. 0.91) was significantly higher in the tumor tissue. However, none of the analyzed Notch-signaling related components showed an association to patient survival. Conclusion: A significant overexpression of almost all studied components of the Notch signaling pathway can be found in the tumor tissue, however, without a significant influence on patient survival. Therefore, further studies are warranted to draw conclusions on Notch pathway’s relevance for patient survival.

CPEB1 orchestrates a fine-tuning of miR-145-5p tumor-suppressive activity on TWIST1 translation in prostate cancer cells

TWIST1 is a basic helix-loop-helix transcription factor, and one of the master Epithelial-to-Mesenchymal Transition (EMT) regulators. We show that tumor suppressor miR-145-5p controls TWIST1 expression in an immortalized prostate epithelial cell line and in a tumorigenic prostate cancer-derived cell line. Indeed, shRNA-mediated miR-145-5p silencing enhanced TWIST1 expression and induced EMT-associated malignant properties in these cells. However, we discovered that the translational inhibitory effect of miR-145-5p on TWIST1 is lost in 22Rv1, another prostate cancer cell line that intrinsically expresses high levels of the CPEB1 cytoplasmic polyadenylation element binding protein. This translational regulator typically reduces TWIST1 translation efficiency by shortening the TWIST1 mRNA polyA tail. However, our results indicate that the presence of CPEB1 also interferes with the binding of miR-145-5p to the TWIST1 mRNA 3′UTR. Mechanistically, CPEB1 binding to its first cognate site either directly hampers the access to the miR-145-5p response element or redirects the cleavage/polyadenylation machinery to an intermediate polyadenylation site, resulting in the elimination of the miR-145-5p binding site. Taken together, our data support the notion that the tumor suppressive activity of miR-145-5p on TWIST1 translation, consequently on EMT, self-renewal, and migration, depends on the CPEB1 expression status of the cancer cell. A preliminary prospective study using clinical samples suggests that reconsidering the relative status of miR-145-5p/TWIST1 and CPEB1 in the tumors of prostate cancer patients may bear prognostic value.

Long non‑coding RNA MEG3 suppresses epithelial‑to‑mesenchymal transition by inhibiting the PSAT1‑dependent GSK‑3β/Snail signaling pathway in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is the main subtype of esophageal cancer in China, and the prognosis of patients remains poor mainly due to the occurrence of lymph node and distant metastasis. The long non‑coding RNA (lncRNA) maternally expressed gene 3 (MEG3) has been shown to have tumor‑suppressive properties and to play an important role in epithelial‑to‑mesenchymal transition (EMT) in some solid tumors. However, whether MEG3 is involved in EMT in ESCC remains unclear. In the present study, the MEG3 expression level and its association with tumorigenesis were determined in 43 tumor tissues of patients with ESCC and in ESCC cells using reverse transcription‑quantitative PCR analysis. Gene microarray analysis was performed to detect differentially expressed genes (DEGs). Based on the functional annotation results, the effects of ectopic expression of MEG3 on cell growth, migration, invasion and EMT were assessed. MEG3 expression level was found to be markedly lower in tumor tissues and cells. Statistical analysis revealed that MEG3 expression was significantly negatively associated with lymph node metastasis and TNM stage in ESCC. Fluorescence in situ hybridization assay demonstrated that MEG3 was expressed mainly in the nucleus. Ectopic expression of MEG3 inhibited cell proliferation, migration, invasion and cell cycle progression in EC109 cells. Gene microarray results demonstrated that 177 genes were differentially expressed ≥2.0 fold in MEG3‑overexpressing cells, including 23 upregulated and 154 downregulated genes. Functional annotation revealed that the DEGs were mainly involved in amino acid biosynthetic process, mitogen‑activated protein kinase signaling, and serine and glycine metabolism. Further experiments indicated that the ectopic expression of MEG3 significantly suppressed cell proliferation, migration, invasion and EMT by downregulating phosphoserine aminotransferase 1 (PSAT1). In pathological tissues, PSAT1 and MEG3 were significantly negatively correlated, and high expression of PSAT1 predicted poor survival. Taken together, these results suggest that MEG3 may be a useful prognostic biomarker and may suppress EMT by inhibiting the PSAT1‑dependent glycogen synthase kinase‑3β/Snail signaling pathway in ESCC.

Notch in Head and Neck Cancer

Head and neck cancer is a group of neoplastic diseases affecting the facial, oral, and neck region. It is one of the most common cancers worldwide with an aggressive, invasive evolution. Due to the heterogeneity of the tissues affected, it is particularly challenging to study the molecular mechanisms at the basis of these tumors, and to date we are still lacking accurate targets for prevention and therapy. The Notch signaling is involved in a variety of tumorigenic mechanisms, such as regulation of the tumor microenvironment, aberrant intercellular communication, and altered metabolism. Here, we provide an up-to-date review of the role of Notch in head and neck cancer and draw parallels with other types of solid tumors where the Notch pathway plays a crucial role in emergence, maintenance, and progression of the disease. We therefore give a perspective view on the importance of the pathway in neoplastic development in order to define future lines of research and novel therapeutic approaches.

Knockout of EGFL6 by CRISPR/Cas9 Mediated Inhibition of Tumor Angiogenesis in Ovarian Cancer

Tumor angiogenesis plays an important role in the progression and metastasis of ovarian cancer. EGFL6 protein is highly expressed in ovarian cancer and has been proposed to play an important role in promoting tumor angiogenesis. Here, a CRISPR/Cas9 system was used to knockout the EGFL6 gene in the ovarian cancer cell line SKOV3, using specific guide RNA targeting the exons of EGFL6. The knockout of EGFL6 markedly inhibited the proliferation, migration, and invasion of SKOV3 cells, as well as promoted apoptosis of tumor cells. In the nude mouse model of ovarian cancer, knockout of EGFL6 remarkably inhibited tumor growth and angiogenesis. The transcript profile assays detected 4,220 differentially expressed genes in the knockout cells, including 87 genes that were correlated to proliferation, migration, invasion, and angiogenesis. Moreover, Western blotting confirmed that EGFL6 knockout downregulated the FGF-2/PDGFB signaling pathway. Thus, the results of this study indicated that EGFL6 could regulate cell proliferation, migration, and angiogenesis in ovarian cancer cells by regulating the FGF-2/PDGFB signaling pathway.

An individualized transcriptional signature to predict the epithelial-mesenchymal transition based on relative expression ordering

The epithelial-mesenchymal transition (EMT) process is involved in cancer cell metastasis and immune system activation. Hence, identification of gene expression signatures capable of predicting the EMT status of cancer cells is essential for development of therapeutic strategies. However, quantitative identification of EMT markers is limited by batch effects, the platform used, or normalization methods. We hypothesized that a set of EMT-related relative expression orderings are highly stable in epithelial samples yet are reversed in mesenchymal samples. To test this hypothesis, we analyzed transcriptome data for ovarian cancer cohorts from publicly available databases, to develop a qualitative 16-gene pair signature (16-GPS) that effectively distinguishes the mesenchymal from epithelial phenotype. Our method was superior to previous quantitative methods in terms of classification accuracy and applicability to individualized patients without requiring data normalization. Patients with mesenchymal-like ovarian cancer showed poorer overall survival compared to patients with epithelial-like ovarian cancer. Additionally, EMT score was positively correlated with expression of immune checkpoint genes and metastasis. We, therefore, established a robust EMT 16-GPS that is independent of detection platform, batch effects and individual variations, and which represents a qualitative signature for investigating the EMT and providing insights into immunotherapy for ovarian cancer patients.

3D culture technologies of cancer stem cells: promising ex vivo tumor models

Cancer stem cells have been shown to be important in tumorigenesis processes, such as tumor growth, metastasis, and recurrence. As such, many three-dimensional models have been developed to establish an ex vivo microenvironment that cancer stem cells experience under in vivo conditions. Cancer stem cells propagating in three-dimensional culture systems show physiologically related signaling pathway profiles, gene expression, cell-matrix and cell-cell interactions, and drug resistance that reflect at least some of the tumor properties seen in vivo. Herein, we discussed the presently available Cancer stem cell three-dimensional culture models that use biomaterials and engineering tools and the biological implications of these models compared to the conventional ones.

CDP-diacylglycerol, a critical intermediate in lipid metabolism

The roles of lipids expand beyond the basic building blocks of biological membranes. In addition to forming complex and dynamic barriers, the thousands of different lipid species in the cell contribute to essentially all the processes of life. Specific lipids are increasingly identified in cellular processes, including signal transduction, membrane trafficking, metabolic control and protein regulation. Tight control of their synthesis and degradation is essential for homeostasis. Most of the lipid molecules in the cell originate from a small number of critical intermediates. Thus, regulating the synthesis of intermediates is essential for lipid homeostasis and optimal biological functions. Cytidine diphosphate diacylglycerol (CDP-DAG) is an intermediate which occupies a branch point in lipid metabolism. CDP-DAG is incorporated into different synthetic pathways to form distinct phospholipid end-products depending on its location of synthesis. Identification and characterization of CDP-DAG synthases which catalyze the synthesis of CDP-DAG has been hampered by difficulties extracting these membrane-bound enzymes for purification. Recent developments have clarified the cellular localization of the CDP-DAG synthases and identified a new unrelated CDP-DAG synthase enzyme. These findings have contributed to a deeper understanding of the extensive synthetic and signaling networks stemming from this key lipid intermediate.

New Insights Into the Role of Phenotypic Plasticity and EMT in Driving Cancer Progression

Tumor cells demonstrate substantial plasticity in their genotypic and phenotypic characteristics. Epithelial-mesenchymal plasticity (EMP) can be characterized into dynamic intermediate states and can be orchestrated by many factors, either intercellularly via epigenetic reprograming, or extracellularly via growth factors, inflammation and/or hypoxia generated by the tumor stromal microenvironment. EMP has the capability to alter phenotype and produce heterogeneity, and thus by changing the whole cancer landscape can attenuate oncogenic signaling networks, invoke anti-apoptotic features, defend against chemotherapeutics and reprogram angiogenic and immune recognition functions. We discuss here the role of phenotypic plasticity in tumor initiation, progression and metastasis and provide an update of the modalities utilized for the molecular characterization of the EMT states and attributes of cellular behavior, including cellular metabolism, in the context of EMP. We also summarize recent findings in dynamic EMP studies that provide new insights into the phenotypic plasticity of EMP flux in cancer and propose therapeutic strategies to impede the metastatic outgrowth of phenotypically heterogeneous tumors.

The RNA-binding protein AKAP8 suppresses tumor metastasis by antagonizing EMT-associated alternative splicing

Alternative splicing has been shown to causally contribute to the epithelial–mesenchymal transition (EMT) and tumor metastasis. However, the scope of splicing factors that govern alternative splicing in these processes remains largely unexplored. Here we report the identification of A-Kinase Anchor Protein (AKAP8) as a splicing regulatory factor that impedes EMT and breast cancer metastasis. AKAP8 not only is capable of inhibiting splicing activity of the EMT-promoting splicing regulator hnRNPM through protein–protein interaction, it also directly binds to RNA and alters splicing outcomes. Genome-wide analysis shows that AKAP8 promotes an epithelial cell state splicing program. Experimental manipulation of an AKAP8 splicing target CLSTN1 revealed that splice isoform switching of CLSTN1 is crucial for EMT. Moreover, AKAP8 expression and the alternative splicing of CLSTN1 predict breast cancer patient survival. Together, our work demonstrates the essentiality of RNA metabolism that impinges on metastatic breast cancer.

Splice isoform switching regulated by the heterogeneous nuclear ribonucleoprotein M (hnRNPM) induces EMT and metastasis. Here, the authors report that AKAP8 is a metastasis suppressor that inhibits the splicing activity of hnRNPM and antagonizes genome-wide EMT-associated alternative splicing to maintain epithelial cell state.

Antitumor activity of celastrol by inhibition of proliferation, invasion, and migration in cholangiocarcinoma via PTEN/PI3K/Akt pathway

AIM

Cholangiocarcinoma is a malignant tumor originating from bile duct epithelium. Currently, the treatment strategy is very limited and the prognosis is poor. Recent studies reported celastrol exhibits antigrowth and antimetastasis properties in many tumors. Our study aimed to assess the anti-CCA effects of cholangiocarcinoma (CCA) and the mechanisms involved in it.

METHODS

In this study, the long-term and short-term antiproliferation effects was determined using colony formation and Cell Counting Kit-8 (CCK-8) assays, respectively. Flow cytometry was performed to quantify apoptosis. Furthermore, wound healing and transwell assays were performed to determine the cell migration and invasion capabilities, respectively. To further find the mechanism involved in the celastrol-induced biological functions, LY204002, a PI3K/Akt signaling inhibitor, and an Akt-1 overexpression plasmid were employed to find whether PI3K/Akt pathway was involved in the celastrol-induced CCA cell inhibition. Additionally, short interfering RNA (siRNA) was also used to investigate the mechanism involved in the celastrol-induced PI3K/Akt signaling inhibition. Western blotting and immunofluorescence assays were also performed to detect the degree of relative proteins. Moreover, we validated the antiproliferation and antimetastasis effects of celastrol in vivo by constructing subcutaneous and lung metastasis nude mice models.

RESULTS

We discovered that celastrol effectively induced apoptotic cell death and inhibited the capacity of migration and invasion in CCA cells. Further mechanistic study identified that celastrol regulated the PI3K/Akt signaling pathway, and the antitumor efficacy was likely due to the upregulation of PTEN, a negative regulator of PI3K/Akt. Blockage of PTEN abolished the celastrol-induced PI3K/Akt signaling inhibition. Additionally, in vivo experiments conformed celastrol inhibited the tumor growth and lung metastasis with no serious side effects.

CONCLUSIONS

Overall, our study elucidated a mechanistic framework for the anti-CCA effects of celastrol via PTEN/PI3K/Akt pathway.

FAM83A signaling induces epithelial-mesenchymal transition by the PI3K/AKT/Snail pathway in NSCLC

Family with sequence similarity 83, member A (FAM83A), as a potential tumor promoter, was reported to contribute to the progression of several malignant tumors. However, the significance of FAM83A in invasion and metastasis of non-small cell lung cancer (NSCLC) remains largely unknown. In this study, we found that FAM83A expression was significantly increased in NSCLC tissues. High expression of FAM83A was positively associated with tumor metastasis and poor survival of NSCLC patients. Functional experiments revealed that FAM83A knockdown could suppress NSCLC cell migration and invasion both in vivo and in vitro. While opposite results were observed in FAM83A-transfected cells. Mechanically, we found that FAM83A promoted NSCLC cell migration and invasion by inducing epithelial-mesenchymal transition (EMT) via PI3K/ATK/Snail signaling. Rescue experiment demonstrated that inhibition of either AKT or Snail could partially counteract the promoting effect of FAM83A overexpression in NSCLC metastasis. Taken together, our findings are the first time to demonstrate that increased expression of FAM83A in NSCLC was correlated with EMT and tumor metastasis, which may provide a novel therapeutic target in NSCLC treatment.

ATXN2L upregulated by epidermal growth factor promotes gastric cancer cell invasiveness and oxaliplatin resistance

For gastric cancer (GC) control, metastasis and chemoresistance are the major challenges, accompanied with various stresses. Ataxin-2-like (ATXN2L) was discovered as a novel regulator of stress granules, yet its function in cancers remained unknown. Hence, we wanted to explore the functions of ATXN2L to see whether it participates in stress-related cancer malignant activities. Clinical follow-up was performed to see the impact of ATXN2L on GC patient survival. As a result, ATXN2L expression was upregulated in GC tissue and indicated adverse prognosis for overall survival and recurrence. In GC cells, ATXN2L expression was knocked down and functional experiments were performed. ATXN2L promoted GC cell migration and invasion via epithelial to mesenchymal transition, yet no influence on proliferation was detected by ATXN2L interference. When adding the chemotherapeutic agent oxaliplatin to induce stress, silencing ATXN2L sensitized GC cells to oxaliplatin. Interestingly, oxaliplatin was found to in turn promote ATXN2L expression and stress granule assembly. Then, two acquired oxaliplatin-resistant strains were generated by long-term oxaliplatin induction. The oxaliplatin-resistant strains presented with elevated ATXN2L levels, while silencing ATXN2L in the strains reversed the oxaliplatin resistance by increasing reactive oxygen species production and apoptosis. These results suggested that ATXN2L was responsible for not only intrinsic but also acquired oxaliplatin chemoresistance. Finally, ATXN2L-related signaling was screened using bioinformatic methods, and epidermal growth factor (EGF) was verified to promote ATXN2L expression via PI3K/Akt signaling activation. Blocking EGFR/ATXN2L signaling reversed GC cell oxaliplatin resistance and inhibited migration. In conclusion, ATXN2L promotes cell invasiveness and oxaliplatin resistance and can be upregulated by EGF via PI3K/Akt signaling. ATXN2L may be an indicator and therapeutic target in GC, especially for oxaliplatin-based chemotherapy.

Acidic Bile Salts Induce Epithelial to Mesenchymal Transition via VEGF Signaling in Non-Neoplastic Barrett's Cells

BACKGROUND & AIMS

Metaplastic glands buried under squamous epithelium are frequently detected in patients with Barrett esophagus (BE). This subsquamous intestinal metaplasia might be responsible for cancers that develop despite endoscopic surveillance and for metaplasia recurrences after endoscopic ablation. To determine whether reflux induces BE cells to undergo an epithelial-to-mesenchymal transition (EMT) that produces subsquamous intestinal metaplasia, we assessed EMT in BE cells exposed to acidic bile salts and in rat and human esophageal tissues.

METHODS

We compared markers of EMT and cell motility in trans-well and 3-dimensional organotypic culture systems among dysplastic BE epithelial cell lines, nondysplastic telomerase-immortalized BE cell lines (BAR-T), and BAR-T cells exposed acutely or for 20 weeks to acidic bile salts. Vascular endothelial growth factor (VEGF) A was inhibited with a neutralizing antibody or CRISPR-Cas9n and VEGF receptor 2 was inhibited with SU1498 or shRNA, and cells were analyzed by immunohistochemistry, quantitative polymerase chain reaction, or immunoblotting for markers of VEGF signaling and EMT; cell motility was assessed by trans-well assay. We used immunohistochemistry and quantitative polymerase chain reaction to assess EMT markers in the columnar-lined esophagus of rats with surgically induced reflux esophagitis and in esophagectomy specimens from patients with BE.

RESULTS

We detected features of EMT (decreased cadherin 1 [CDH1]; increased fibronectin 1, vimentin, and matrix metalloproteinase 2; and increased motility) in dysplastic BE epithelial cell lines and in BAR-T cells exposed for 20 weeks, but not in unexposed BAR-T cells. Acute acidic bile salt exposure induced expression of zinc finger E-box binding homeobox 1 and 2 (ZEB1/2) in BAR-T cells, which decreased their expression of CDH1 and increased motility; inhibitors of VEGF signaling blocked these effects. Columnar-lined esophagus of rats with reflux esophagitis had increased expression of ZEB1/2 and decreased expression of CDH1 compared with controls. Dysplastic BE tissues also had significantly increased levels of ZEB1 and significantly decreased levels of CDH1 compared with nondysplastic BE tissues.

CONCLUSIONS

In BE cell lines, acidic bile salts induce EMT by VEGF signaling, which increases expression of ZEB1/2, repressors of CDH1. These observations suggest that reflux induces EMT in metaplastic BE tissues, which promotes development of subsquamous intestinal metaplasia.

O-GlcNAcylation is required for mutant KRAS-induced lung tumorigenesis

Mutant KRAS drives glycolytic flux in lung cancer, potentially impacting aberrant protein glycosylation. Recent evidence suggests aberrant KRAS drives flux of glucose into the hexosamine biosynthetic pathway (HBP). HBP is required for various glycosylation processes, such as protein N- or O-glycosylation and glycolipid synthesis. However, its function during tumorigenesis is poorly understood. One contributor and proposed target of KRAS-driven cancers is a developmentally conserved epithelial plasticity program called epithelial-mesenchymal transition (EMT). Here we showed in novel autochthonous mouse models that EMT accelerated KrasG12D lung tumorigenesis by upregulating expression of key enzymes of the HBP pathway. We demonstrated that HBP was required for suppressing KrasG12D-induced senescence, and targeting HBP significantly delayed KrasG12D lung tumorigenesis. To explore the mechanism, we investigated protein glycosylation downstream of HBP and found elevated levels of O-linked β-N-acetylglucosamine (O-GlcNAcylation) posttranslational modification on intracellular proteins. O-GlcNAcylation suppressed KrasG12D oncogene-induced senescence (OIS) and accelerated lung tumorigenesis. Conversely, loss of O-GlcNAcylation delayed lung tumorigenesis. O-GlcNAcylation of proteins SNAI1 and c-MYC correlated with the EMT-HBP axis and accelerated lung tumorigenesis. Our results demonstrated that O-GlcNAcylation was sufficient and required to accelerate KrasG12D lung tumorigenesis in vivo, which was reinforced by epithelial plasticity programs.

Knockdown of Cripto-1 inhibits the proliferation, migration, invasion, and angiogenesis in prostate carcinoma cells

Cripto-1 (CR-1) is a member of the epidermal growth factor-Cripto-1/FRL1/Cryptic gene family that plays a key role in the various malignant cancers. However, the role of CR-1 in prostate carcinoma (PCa) remains limited. The expression of CR-1 was down-regulated by small interfering RNA (siRNA). Western blot measured the expression levels of CR-1 and some related proteins. We performed Cell Counting Kit-8, 5-ethynyl-2-deoxyuridine (EdU) incorporation assay and flow cytometry to detect the cellular proliferation and cycle. The transwell assay was used to observe cellular migration and invasion. The ability of angiogenesis was evaluated by tube formation assay. Our results showed that CR-1 knockdown markedly inhibited cell proliferation and induced cycle arrest in G1 phase, as p21 and p27 were up-regulated, whereas cyclin D1 and cyclin E1 were diminished. Moreover, silencing of CR-1 dramatically inhibited cell migration and invasion, repressed matrix metalloproteinases, and disturbed epithelial-mesenchymal transition. CR-1 siRNA suppressed the secreted level of vascular endothelial growth factor, and reduced protein level of Vascular endothelial growth factor receptor 2. We further found that decreased CR-1 expression inhibited FAK/Src/PI3K and Wnt/b-catenin signalling in PCa cells. These results suggested CR-1 might be served as an effective therapeutic target in PCa.

MicroRNA-494 acts as a tumor suppressor in pancreatic cancer, inhibiting epithelial-mesenchymal transition, migration and invasion by binding to SDC1

Pancreatic cancer (PC) is the fourth most common cause of cancer‑related mortality in the industrialized world. Emerging evidence indicates that a variety of microRNAs (miRNAs or miRs) are involved in the development of PC. The aim of the present study was to elucidate the mechanisms through which miR‑494 affects the epithelial‑mesenchymal transition (EMT) and invasion of PC cells by binding to syndecan 1 (SDC1). PC tissues and pancreatitis tissues were collected, and the regulatory effects of miR‑494 on SDC1 were validated using bioinformatics analysis and a dual‑luciferase report gene assay. The cell line with the highest SDC1 expression was selected for use in the following experiments. The role of miR‑494 in EMT was assessed by measuring the expression of SDC1, E‑cadherin and vimentin. Cell proliferation was assessed using a cell counting kit (CCK)‑8 assay, migration was measured using a scratch test, invasion was assessed with a Transwell assay and apoptosis was detected by flow cytometry. Finally, a xenograft tumor model was constructed in nude mice to observe tumor growth in vivo. We found that SDC1 protein expression was significantly higher in the PC tissues. SDC1 was verified as a target gene of miR‑494. The SW1990 cell line was selected for use in further experiments as it had the lowest miR‑494 expression and the highest SDC1 expression. Our results also demonstrated that miR‑494 overexpression and SDC1 silencing significantly decreased the mRNA and protein expression of SDC1 and vimentin in SW1990 cells, while it increased E‑cadherin expression and apoptosis, and inhibited cell growth, migration, invasion and tumor growth. On the whole, the findings of this study demonstrated that miR‑494 is able to downregulate SDC1 expression, thereby inhibiting the progression of PC. These findings reveal a novel mechanism through which miR‑494 affects the development of PC and may thus provide a basis for the application of miR‑494 in pancreatic oncology.

Antrodia cinnamomea mycelial fermentation broth inhibits the epithelial-mesenchymal transition of human esophageal adenocarcinoma cancer cells

Esophageal cancer is associated with a high mortality rate and easy metastasis. The aim of this study is to investigate the effect of the bio-product Antrodia cinnamomea mycelial fermentation broth (AC-MFB) on the epithelial mesenchymal transition (EMT) of human esophageal cancer cells and the molecular mechanisms underlying these effects. Transforming growth factor β (TGF-β) was used to induce EMT in human esophageal BE3 cancer cells. Changes in cell morphology and migration potential were examined. The expression of E-cadherin, N-cadherin, vimentin, and other transcriptional factors was studied by western blot assay. The results showed that AC-MFB was not only able to upregulate the expression of Ecadherin and attenuate the TGF-β-induced overexpression of vimentin and N-cadherin, but it also reversed the TGF-β-induced changes in cell morphology from polygonal to spindle-shaped and delayed the migration potential of BE3 cells. Furthermore, AC-MFB treatment was able to inhibit the expression levels of both Twist and Twist1. Overall, AC-MFB was able to inhibit the EMT of esophageal cancer BE3 cells, which was accompanied by Twist and Twist1 downregulation.

Regulation of cellular quiescence by YAP/TAZ and Cyclin E1 in colon cancer cells: Implication in chemoresistance and cancer relapse

Our aim was to decipher the role and clinical relevance of the YAP/TAZ transcriptional coactivators in the regulation of the proliferation/quiescence balance in human colon cancer cells (CCC) and survival after 5FU-based chemotherapy. The prognostic value of YAP/TAZ on tumor relapse and overall survival was assessed in a five-year follow-up study using specimens of liver metastases (n = 70) from colon cancer patients. In 5FU-chemoresistant HT29-5F31 and -chemosensitive HCT116 and RKO CCC, a reversible G0 quiescent state mediated by Cyclin E1 down-regulation was induced by 5FU in 5F31 cells and recapitulated in CCC by either YAP/TAZ or Cyclin E1 siRNAs or the YAP inhibitor Verteporfin. Conversely, the constitutive active YAPdc-S127A mutant restricted cellular quiescence in 5FU-treated 5F31 cells and sustained high Cyclin E1 levels through CREB Ser-133 phosphorylation and activation. In colon cancer patients, high YAP/TAZ level in residual liver metastases correlated with the proliferation marker Ki-67 (p < 0.0001), high level of the YAP target CTGF (p = 0.01), shorter disease-free and overall survival (p = 0.008 and 0.04, respectively). By multivariate analysis and Cox regression model, the YAP/TAZ level was an independent factor of overall (Hazard ratio [CI 95%] 2.06 (1.02–4.16) p = 0.045) and disease-free survival (Hazard ratio [CI 95%] 1.98 (1.01–3.86) p = 0.045). Thus, YAP/ TAZ pathways contribute to the proliferation/quiescence switch during 5FU treatment according to the concerted regulation of Cyclin E1 and CREB. These findings provide a rationale for therapeutic interventions targeting these transcriptional regulators in patients with residual chemoresistant liver metastases expressing high YAP/TAZ levels.

A role for G-protein coupled estrogen receptor (GPER) in estrogen-induced carcinogenesis: Dysregulated glandular homeostasis, survival and metastasis

Mechanisms of carcinogenesis by estrogen center on its mitogenic and genotoxic potential on tumor target cells. These models suggest that estrogen receptor (ER) signaling promotes expansion of the transformed population and that subsequent accumulation of somatic mutations that drive cancer progression occur via metabolic activation of cathecol estrogens or by epigenetic mechanisms. Recent findings that GPER is linked to obesity, vascular pathology and immunosuppression, key events in the development of metabolic syndrome and intra-tissular estrogen synthesis, provides an alternate view of estrogen-induced carcinogenesis. Consistent with this concept, GPER is directly associated with clinicopathological indices that predict cancer progression and poor survival in breast and gynecological cancers. Moreover, GPER manifests cell biological responses and a microenvironment conducive for tumor development and cancer progression, regulating cellular responses associated with glandular homeostasis and survival, invading surrounding tissue and attracting a vascular supply. Thus, the cellular actions attributed to GPER fit well with the known molecular mechanisms of G-protein coupled receptors, GPCRs, namely, their ability to transactivate integrins and EGF receptors and alter the interaction between glandular epithelia and their extracellular environment, affecting epithelial-to-mesenchymal transition (EMT) and allowing for tumor cell survival and dissemination. This perspective reviews the molecular and cellular responses manifested by GPER and evaluates its contribution to female reproductive cancers as diseases that progress as a result of dysregulated glandular homeostasis resulting in chronic inflammation and metastasis. This review is organized in sections as follows: I) a brief synopsis of the current state of knowledge regarding estrogen-induced carcinogenesis, II) a review of evidence from clinical and animal-based studies that support a role for GPER in cancer progression, and III) a mechanistic framework describing how GPER-mediated estrogen action may influence the tumor and its microenvironment.

Expression of Vimentin in hair follicle growth cycle of inner Mongolian Cashmere goats

Background

The growth of Inner Mongolian Cashmere goat skin hair follicle exhibits a periodic growth pattern. The hair growth cycle is distinguished as telogen, anagen, and catagen stages. The role of vimentin in the growth process of hair follicles is evident. To elucidate the mechanism underlying the vimentin activity in the growth cycle of hair follicles, transcriptome sequencing and liquid chromatography-tandem mass spectrometry were used to obtain the nucleic acid and amino acid sequences of VIIM gene and vimentin. The amino acid and nucleic acid sequences were analyzed by comparison. Real-time quantitative PCR, Western blot, and immunohistochemistry analyzed the expression level and sites of vimentin in the three growth stages of the Inner Mongolia Cashmere goat skin samples.

Results

VIM gene cDNA, obtained by transcriptome sequencing, was aligned against that of the Capra hircus VIM gene. The amino acid sequence of vimentin revealed a high similarity rate across other species. The expressions of both VIM gene and vimentin were highest during the growth period and lowest in the rest period. Furthermore, vimentin was primarily expressed in the outer root sheath of the hair follicle as assessed by staining.

Conclusions

The sequences of the gene and protein are similar to that of other species and identical to Capra hircus. However, the expression of VIM and vimentin was proportional to that of the growth of hair follicles. And vimentin expressed only in the outer root sheath of hair follicles. Thus, vimentin was speculated to participate in the regulation of the hair follicle growth cycle by affecting the outer root sheath.

The Interplay Between Epithelial-Mesenchymal Transition (EMT) and the Thyroid Hormones-αvβ3 Axis in Ovarian Cancer

Ovarian cancer is a highly metastatic disease. The metastatic potential is enhanced by epithelial to mesenchymal transition (EMT) in which αvβ3 integrin plays a role. Thyroid hormones (L-thyroxine, T4, and 3,5,3'-triiodo-L-thyronine, T3) bind this integrin, and we hypothesized that the thyroid hormone-αvβ3 axis may be involved in EMT activity in ovarian cancer. The transcription (mRNA), protein abundance (westerns), and protein localization (fluorescence microscopy) of several EMT markers were studied in ovarian cancer cells (OVCAR-3, A2780, and SKOV-3) treated with 1 nM T3 or 100 nM T4 for 1-24 h. The protein levels of β-catenin, and its downstream targets, zeb-1, slug, and vimentin, were significantly induced by both hormones, while the effect on transcription was limited. The pre-incubation of the cells overnight with two integrin inhibitors, RGD (0.1-10 μM) or αvβ3 blocking antibody (1-100 ng/mL), prevented the induction of β-catenin by T3 and zeb-1 by T4, indicating direct integrin involvement. The transcription of the mesenchymal markers, β-catenin, zeb-1, slug/snail, vimentin, and n-cadherin was hardly affected by T3 and T4, while that of the epithelial markers, e-cadherin and zo-1, was inhibited. Our results suggest a novel role for the thyroid hormone-αvβ3 axis in EMT, with possible implications for ovarian cancer metastasis.