Targeting EMT in cancer: opportunities for pharmacological intervention

Particulate matter promotes cancer metastasis through increased HBEGF expression in macrophages

Although many cohort studies have reported that long-term exposure to particulate matter (PM) can cause lung cancer, the molecular mechanisms underlying the PM-induced increase in cancer metastasis remain unclear. To determine whether PM contributes to cancer metastasis, cancer cells were cultured with conditioned medium from PM-treated THP1 cells, and the migration ability of the treated cancer cells was assessed. The key molecules involved were identified using RNA-seq analysis. In addition, metastatic ability was analyzed in vivo by injection of cancer cells into the tail vein and intratracheal injection of PM into the lungs of C57BL/6 mice. We found that PM enhances the expression of heparin-binding EGF-like growth factor (HBEGF) in macrophages, which induces epithelial-to-mesenchymal transition (EMT) in cancer cells, thereby increasing metastasis. Macrophage stimulation by PM results in activation and subsequent nuclear translocation of the aryl hydrocarbon receptor and upregulation of HBEGF. Secreted HBEGF activates EGFR on the cancer cell surface to induce EMT, resulting in increased migration and invasion in vitro and increased metastasis in vivo. Therefore, our study reveals a critical PM-macrophage-cancer cell signaling axis mediating EMT and metastasis and provides an effective therapeutic approach for PM-induced malignancy.

The role of heat shock proteins in metastatic colorectal cancer: A review

Heat shock proteins (HSPs) are a large molecular chaperone family classified by their molecular weights, including HSP27, HSP40, HSP60, HSP70, HSP90, and HSP110. HSPs are likely to have antiapoptotic properties and participate actively in various processes such as tumor cell proliferation, invasion, metastases, and death. In this review, we discuss comprehensively the functions of HSPs associated with the progression of colorectal cancer (CRC) and metastasis and resistance to cancer therapy. Taken together, HSPs have numerous clinical applications as biomarkers for cancer diagnosis and prognosis and potential therapeutic targets for CRC and its related metastases.

Poziotinib for EGFR exon 20-mutant NSCLC: Clinical efficacy, resistance mechanisms, and impact of insertion location on drug sensitivity

We report a phase II study of 50 advanced non-small cell lung cancer (NSCLC) patients with point mutations or insertions in EGFR exon 20 treated with poziotinib (NCT03066206). The study achieved its primary endpoint, with confirmed objective response rates (ORRs) of 32% and 31% by investigator and blinded independent review, respectively, with a median progression-free survival of 5.5 months. Using preclinical studies, in silico modeling, and molecular dynamics simulations, we found that poziotinib sensitivity was highly dependent on the insertion location, with near-loop insertions (amino acids A767 to P772) being more sensitive than far-loop insertions, an observation confirmed clinically with ORRs of 46% and 0% observed in near versus far-loop, respectively (p = 0.0015). Putative mechanisms of acquired resistance included EGFR T790M, MET amplifications, and epithelial-to-mesenchymal transition (EMT). Our data demonstrate that poziotinib is active in EGFR exon 20-mutant NSCLC, although this activity is influenced by insertion location.

Rg3 and Rh2 ginsenosides suppress embryoid body formation by inhibiting the epithelial-mesenchymal transition

Numerous active compounds derived from ginseng exhibit various pharmacological and therapeutic effects in humans. Despite the benefits of ginsenosides, little is known about their influence on embryonic development, especially in human embryonic models. In this study, we evaluated the effect of two ginsenosides (Rg3 and Rh2) on human embryonic development, using embryoid bodies and three-dimensional (3D) aggregates of pluripotent stem cells. We exposed embryoid bodies to varying concentrations of Rg3 and Rh2 (5, 10, and 25 μg/mL), and their embryotoxicity was evaluated by measuring the size of the embryoid body and the expression of epithelial-mesenchymal transition (EMT) markers. The growth rates of embryoid bodies were reduced upon treatment with a high concentration (25 μg/mL) of Rg3 and Rh2. In addition, Rg3 induced E-cadherin expression while inhibiting N-cadherin and vimentin expression, which implies the inhibition of EMT. Such a change in E-cadherin expression was not observed after Rh2 treatment, but the inhibition of N-cadherin and vimentin expression was observed to be consistent with that observed on treatment with Rg3. Taken together, using the human embryoid model, we found that the two active ginsenosides, Rg3 and Rh2, induce aberrant embryoid body formation and ablate normal EMT.

TGF-β1 receptor blockade attenuates unilateral ureteral obstruction-induced renal fibrosis in C57BL/6 mice through attenuating Smad and MAPK pathways

Renal fibrosis is characterized by accumulation of extracellular matrix components and collagen deposition. TGF-β1 acts as a master switch promoting renal fibrosis through Smad dependent and/or Smad independent pathways. Thirty-five male C57BL/6 mice were divided into five groups of seven each; sham, unilateral ureteral obstruction (UUO), UUO+galunisertib (150 and 300 mg/kg/day), galunisertib (300 mg/kg/day). The UUO markedly induced renal fibrosis and injury as indicated by renal functional loss, increased levels of collagen Iα1, fibronectin and α-SMA; it also activated both the Smad 2/3 and MAPKs pathways as indicated by increased levels of TGF-β1, p-Smad 2, p-Smad 3, p-p38, p-JNK and p-ERK. These UUO-induced changes were markedly attenuated by oral administration of galunisertib, the TGFβRI small molecule inhibitor. In conclusion, we demonstrated that TGF-β1 receptor blockade can prevent UUO-induced renal fibrosis through indirect modulation of Smad and MAPKs signaling pathways and may be useful as a therapeutic agent in treatment and/or prevention of renal fibrosis.

Pancreatic cancer cells spectral library by DIA-MS and the phenotype analysis of gemcitabine sensitivity

Data-independent acquisition (DIA)-mass spectrometry (MS)-based proteome strategies are increasingly used for detecting and validating protein biomarkers and therapeutic targets. Here, based on an in-depth proteome analysis of seven pancreatic cancer cell lines, we built a pancreas-specific mass spectrum library containing 10633 protein groups and 184551 peptides. The proteome difference among the seven pancreatic cancer cells was significant, especially for the divergent expression of proteins related to epithelial-mesenchymal transition (EMT). The spectra library was applied to explore the proteome difference of PANC-1 and BxPC-3 cells upon gemcitabine (GEM) treatment, and potential GEM targets were identified. The cytotoxicity test and GEM target analysis found that HPAC, CFPAC-1, and BxPC-3 were sensitive to GEM treatment, whereas PANC-1 and AsPC-1 were resistant. Finally, we found EMT was significant for CFPAC-1, AsPC-1, and PANC-1 cells, whereas BxPC-3 and HPAC cells showed more typical epithelial features. This library provides a valuable resource for in-depth proteomic analysis on pancreatic cancer cell lines, meeting the urgent demands for cell line-dependent protein differences and targeted drug analysis.

Measurement(s)	protein expression profiling
Technology Type(s)	Mass Spectrometry

A repositioning screen using an FGFR2 splicing reporter reveals compounds that regulate epithelial-mesenchymal transitions and inhibit growth of prostate cancer xenografts

Research in the area of hallmarks of cancer has opened the possibility of designing new therapies based on modulating these cancer properties. We present here a screen designed to find chemicals that modulate epithelial-mesenchymal transitions (EMTs) in prostate cancer. For screening, we used a repurposing library and, as a readout, an FGFR2-based splicing reporter, which has been shown previously to be a sensor for EMTs. Various properties of cancer cells were assessed, signaling pathways investigated, and in vivo experiments in nude mice xenografts performed. The screen yielded three hit compounds (a T-type Ca channel inhibitor, an L-type Ca channel inhibitor, and an opioid antagonist) that switch FGFR2 splicing and induce an epithelial phenotype in prostate cancer cells. The compounds affected differently various properties of cancer cells, but all of them decreased cell migration, which is in line with modulating EMTs. We further present mechanistic insights into one of the compounds, nemadipine-A. The administration of nemadipine-A intraperitoneally in a nude mouse xenograft model of prostate cancer slowed tumor growth. To conclude, we show that knowledge of the molecular mechanisms that connect alternative splicing and various cancer properties may be used as a platform for drug development.

Identification of EMT-Related Genes and Prognostic Signature With Significant Implications on Biological Properties and Oncology Treatment of Lower Grade Gliomas

The epithelial-mesenchymal transition (EMT) is an important process that drives progression, metastasis, and oncology treatment resistance in cancers. Also, the adjacent non-tumor tissue may affect the biological properties of cancers and have potential prognostic implications. Our study aimed to identify EMT-related genes in LGG samples, explore their impact on the biological properties of lower grade gliomas (LGG) through the multi-omics analysis, and reveal the potential mechanism by which adjacent non-tumor tissue participated in the malignant progression of LGG. Based on the 121 differentially expressed EMT-related genes between normal samples from the GTEx database and LGG samples in the TCGA cohort, we identified two subtypes and constructed EMTsig. Because of the genetic, epigenetic, and transcriptomic heterogeneity, malignant features including clinical traits, molecular traits, metabolism, anti-tumor immunity, and stemness features were different between samples with C1 and C2. In addition, EMTsig could also quantify the EMT levels, variation in prognosis, and oncology treatment sensitivity of LGG patients. Therefore, EMTsig could assist us in developing objective diagnostic tools and in optimizing therapeutic strategies for LGG patients. Notably, with the GSVA, we found that adjacent non-tumor tissue might participate in the progression, metastasis, and formation of the tumor microenvironment in LGG. Therefore, the potential prognostic implications of adjacent non-tumor tissue should be considered when performing clinical interventions for LGG patients. Overall, our study investigated and validated the effects of EMT-related genes on the biological properties from multiple perspectives, and provided new insights into the function of adjacent non-tumor tissue in the malignant progression of LGG.

Epithelial–mesenchymal transition: The history, regulatory mechanism, and cancer therapeutic opportunities

Epithelial–mesenchymal transition (EMT) is a program wherein epithelial cells lose their junctions and polarity while acquiring mesenchymal properties and invasive ability. Originally defined as an embryogenesis event, EMT has been recognized as a crucial process in tumor progression. During EMT, cell–cell junctions and cell–matrix attachments are disrupted, and the cytoskeleton is remodeled to enhance mobility of cells. This transition of phenotype is largely driven by a group of key transcription factors, typically Snail, Twist, and ZEB, through epigenetic repression of epithelial markers, transcriptional activation of matrix metalloproteinases, and reorganization of cytoskeleton. Mechanistically, EMT is orchestrated by multiple pathways, especially those involved in embryogenesis such as TGFβ, Wnt, Hedgehog, and Hippo, suggesting EMT as an intrinsic link between embryonic development and cancer progression. In addition, redox signaling has also emerged as critical EMT modulator. EMT confers cancer cells with increased metastatic potential and drug resistant capacity, which accounts for tumor recurrence in most clinic cases. Thus, targeting EMT can be a therapeutic option providing a chance of cure for cancer patients. Here, we introduce a brief history of EMT and summarize recent advances in understanding EMT mechanisms, as well as highlighting the therapeutic opportunities by targeting EMT in cancer treatment.

EGFR inhibition reverses epithelial‑mesenchymal transition, and decreases tamoxifen resistance via Snail and Twist downregulation in breast cancer cells

Tamoxifen resistance remains a major obstacle in the treatment of estrogen receptor (ER)‑positive breast cancer. In recent years, the crucial role of the epithelial‑mesenchymal transition (EMT) process in the development of drug resistance in breast cancer has been underlined. However, the central molecules inducing the EMT process during the development of tamoxifen resistance remain to be elucidated. In the present study, it was demonstrated that tamoxifen‑resistant breast cancer cells underwent EMT and exhibited an enhanced cell motility and invasive behavior. The inhibition of snail family transcriptional repressor 1 (Snail) and twist family BHLH transcription factor 1 (Twist) reversed the EMT phenotype and decreased the tamoxifen resistance, migration and invasion of tamoxifen‑resistant breast cancer cells. In addition, it was observed that the inhibition of epidermal growth factor receptor (EGFR) reversed the EMT phenotype in tamoxifen‑resistant MCF7 (MCF‑7/TR) cells via the downregulation of Snail and Twist. Notably, the EGFR inhibitor, gefitinib, decreased tamoxifen resistance, migration and invasion through the inhibition of Snail and Twist. On the whole, the results of the present study suggest that EGFR may be a promising therapeutic target for tamoxifen‑resistant breast cancer. Moreover, it was suggested that gefitinib may serve as a potent novel therapeutic strategy for breast cancer patients, who have developed tamoxifen resistance.

Targeting key proteins involved in transcriptional regulation for cancer therapy: Current strategies and future prospective

The key proteins involved in transcriptional regulation play convergent roles in cellular homeostasis, and their dysfunction mediates aberrant gene expressions that underline the hallmarks of tumorigenesis. As tumor progression is dependent on such abnormal regulation of transcription, it is important to discover novel chemical entities as antitumor drugs that target key tumor-associated proteins involved in transcriptional regulation. Despite most key proteins (especially transcription factors) involved in transcriptional regulation are historically recognized as undruggable targets, multiple targeting approaches at diverse levels of transcriptional regulation, such as epigenetic intervention, inhibition of DNA-binding of transcriptional factors, and inhibition of the protein-protein interactions (PPIs), have been established in preclinically or clinically studies. In addition, several new approaches have recently been described, such as targeting proteasomal degradation and eliciting synthetic lethality. This review will emphasize on accentuating these developing therapeutic approaches and provide a thorough conspectus of the drug development to target key proteins involved in transcriptional regulation and their impact on future oncotherapy.

Ion Channel Involvement in Tumor Drug Resistance

Over 90% of deaths in cancer patients are attributed to tumor drug resistance. Resistance to therapeutic agents can be due to an innate property of cancer cells or can be acquired during chemotherapy. In recent years, it has become increasingly clear that regulation of membrane ion channels is an important mechanism in the development of chemoresistance. Here, we review the contribution of ion channels in drug resistance of various types of cancers, evaluating their potential in clinical management. Several molecular mechanisms have been proposed, including evasion of apoptosis, cell cycle arrest, decreased drug accumulation in cancer cells, and activation of alternative escape pathways such as autophagy. Each of these mechanisms leads to a reduction of the therapeutic efficacy of administered drugs, causing more difficulty in cancer treatment. Thus, targeting ion channels might represent a good option for adjuvant therapies in order to counteract chemoresistance development.

ID09, A Newly-Designed Tubulin Inhibitor, Regulating the Proliferation, Migration, EMT Process and Apoptosis of Oral Squamous Cell Carcinoma

Microtubules, a major target in oral squamous cell carcinoma (OSCC) chemotherapy, contribute to multiple malignant biological behaviors, including proliferation, migration, and epithelial-mesenchymal transition (EMT). Surpassing traditional tubulin inhibitors, ID09 emerges with brilliant solubility, photostability, and drug-sensitivity in multidrug-resistant cells. Its anti-tumor effects have been briefly verified in lung adenocarcinoma and hepatocellular carcinoma. However, whether OSCC is sensitive to ID09 and the potential mechanisms remain ambiguous, which are research purposes this study aimed to achieve. Various approaches were applied, including clone formation assay, flow cytometry, wound healing assay, Transwell assay, cell counting kit-8 assay, Western blot, qRT-PCR, and in vivo experiment. The experimental results revealed that ID09 not only contributed to cell cycle arrest, reduced migration, and reversed EMT, but accelerated mitochondria-initiated apoptosis. Remarkably, Western blot detected diminishment in expression of Mcl-1 due to the deactivation of Ras-Erk pathway, resulting in ID09-induced apoptosis, proliferation and migration suppression, which could be offset by Erk1/2 phosphorylation agonist Ro 67-7476. This study initially explored the essential role Mcl-1 played and the regulatory effect of Ras-Erk pathway in anti-cancer process triggered by tubulin inhibitor, broadening clinical horizon of tubulin inhibitors in oral squamous cell carcinoma chemotherapy application.

Nobiletin Inhibits Non-Small-Cell Lung Cancer by Inactivating WNT/β-Catenin Signaling through Downregulating miR-15-5p

BACKGROUND

Nobiletin is a natural compound with anticancer activity; however, the mechanism is not clear.

METHODS

The inhibitory effect of nobiletin on non-small-cell lung cancer (NSCLC) cells was examined using soft agar, Transwell, and apoptosis analyses. Cancer stemness was measured by sphere assay. Genes and miRNAs regulated by nobiletin were identified by whole-genome sequencing. Protein levels were detected by western blot and immunofluorescence assays.

RESULTS

Nobiletin significantly inhibited NSCLC cell colony formation and sphere formation and induced apoptosis. Nobiletin upregulated negative regulators of WNT/β-catenin signaling, including NKD1, AXIN2, and WIF1, while it inhibited the expression of β-catenin and its downstream genes, including c-Myc, c-Jun, and cyclin D1. Furthermore, we identified that GN inhibits miR-15-5p expression in NSCLC cells and that NKD1, AXIN2, and WIF1 are the target genes of miR-15-5p.

CONCLUSIONS

Nobiletin has a strong inhibitory effect on NSCLC, and nobiletin plays an anticancer role by inhibiting miR-15-5p/β-catenin signaling in NSCLC.

Molecular classification of gastric cancer predicts survival in patients undergoing radical gastrectomy based on project HOPE

BACKGROUND

Gastric cancer (GC) has been classified based on molecular profiling like The Cancer Genome Atlas (TCGA) and Asian Cancer Research Group (ACRG), and attempts have been made to establish therapeutic strategies based on these classifications. However, it is difficult to predict the survival according to these classifications especially in radically resected patients. We aimed to establish a new molecular classification of GC which predicts the survival in patients undergoing radical gastrectomy.

METHODS

The present study included 499 Japanese patients with advanced GC undergoing radical (R0/R1) gastrectomy. Whole-exome sequencing, panel sequencing, and gene expression profiling were conducted (High-tech Omics-based Patient Evaluation [Project HOPE]). We classified patients according to TCGA and ACRG subtypes, and evaluated the clinicopathologic features and survival. Then, we attempted to classify patients according to their molecular profiles associated with biological features and survival (HOPE classification).

RESULTS

TCGA and ACRG classifications failed to predict the survival. In HOPE classification, hypermutated (HMT) tumors were selected first as a distinctive feature, and T-cell-inflamed expression signature-high (TCI) tumors were then extracted. Finally, the remaining tumors were divided by the epithelial-mesenchymal transition (EMT) expression signature. HOPE classification significantly predicted the disease-specific and overall survival (p < 0.001 and 0.020, respectively). HMT + TCI showed the best survival, while EMT-high showed the worst survival. The HOPE classification was successfully validated in the TCGA cohort.

CONCLUSIONS

We established a new molecular classification of gastric cancer that predicts the survival in patients undergoing radical surgery.

KIAA1217 Promotes Epithelial-Mesenchymal Transition and Hepatocellular Carcinoma Metastasis by Interacting with and Activating STAT3

The survival and prognosis of hepatocellular carcinoma (HCC) are poor, mainly due to metastasis. Therefore, insights into the molecular mechanisms underlying HCC invasion and metastasis are urgently needed to develop a more effective antimetastatic therapy. Here, we report that KIAA1217, a functionally unknown macromolecular protein, plays a crucial role in HCC metastasis. KIAA1217 expression was frequently upregulated in HCC cell lines and tissues, and high KIAA1217 expression was closely associated with shorter survival of patients with HCC. Overexpression and knockdown experiments revealed that KIAA1217 significantly promoted cell migration and invasion by inducing epithelial-mesenchymal transition (EMT) in vitro. Consistently, HCC cells overexpressing KIAA1217 exhibited markedly enhanced lung metastasis in vivo. Mechanistically, KIAA1217 enhanced EMT and accordingly promoted HCC metastasis by interacting with and activating JAK1/2 and STAT3. Interestingly, KIAA1217-activated p-STAT3 was retained in the cytoplasm instead of translocating into the nucleus, where p-STAT3 subsequently activated the Notch and Wnt/β-catenin pathways to facilitate EMT induction and HCC metastasis. Collectively, KIAA1217 may function as an adaptor protein or scaffold protein in the cytoplasm and coordinate multiple pathways to promote EMT-induced HCC metastasis, indicating its potential as a therapeutic target for curbing HCC metastasis.

Methionine aminopeptidase‑2 is a pivotal regulator of vasculogenic mimicry

Vasculogenic mimicry (VM) is the formation of a blood supply system that confers aggressive and metastatic properties to tumors and correlates with a poor prognosis in cancer patients. Thus, the inhibition of VM is considered an effective approach for cancer treatment, although such a mechanism remains poorly described. In the present study, we examined methionine aminopeptidase-2 (MetAP2), a key factor of angiogenesis, and demonstrated that it is pivotal for VM, using pharmacological and genetic approaches. Fumagillin and TNP-470, angiogenesis inhibitors that target MetAP2, significantly suppressed VM in various human cancer cell lines. We established MetAP2-knockout (KO) human fibrosarcoma HT1080 cells using the CRISPR/Cas9 system and found that VM was attenuated in these cells. Furthermore, re-expression of wild-type MetAP2 restored VM in the MetAP2-KO HT1080 cells, but the substitution of D251, a conserved amino acid in MetAP2, failed to rescue the VM. Collectively, our results demonstrate that MetAP2 is critical for VM in human cancer cells and suggest fumagillin and TNP-470 as potent VM-suppressing agents.

Tumor metastasis: Mechanistic insights and therapeutic interventions

Cancer metastasis is responsible for the vast majority of cancer-related deaths worldwide. In contrast to numerous discoveries that reveal the detailed mechanisms leading to the formation of the primary tumor, the biological underpinnings of the metastatic disease remain poorly understood. Cancer metastasis is a complex process in which cancer cells escape from the primary tumor, settle, and grow at other parts of the body. Epithelial-mesenchymal transition and anoikis resistance of tumor cells are the main forces to promote metastasis, and multiple components in the tumor microenvironment and their complicated crosstalk with cancer cells are closely involved in distant metastasis. In addition to the three cornerstones of tumor treatment, surgery, chemotherapy, and radiotherapy, novel treatment approaches including targeted therapy and immunotherapy have been established in patients with metastatic cancer. Although the cancer survival rate has been greatly improved over the years, it is still far from satisfactory. In this review, we provided an overview of the metastasis process, summarized the cellular and molecular mechanisms involved in the dissemination and distant metastasis of cancer cells, and reviewed the important advances in interventions for cancer metastasis.

RNA binding protein RBMS3 is a common EMT effector that modulates triple-negative breast cancer progression via stabilizing PRRX1 mRNA

The epithelial-to-mesenchymal transition (EMT) has been recognized as a driving force for tumor progression in breast cancer. Recently, our group identified the RNA Binding Motif Single Stranded Interacting Protein 3 (RBMS3) to be significantly associated with an EMT transcriptional program in breast cancer. Additional expression profiling demonstrated that RBMS3 was consistently upregulated by multiple EMT transcription factors and correlated with mesenchymal gene expression in breast cancer cell lines. Functionally, RBMS3 was sufficient to induce EMT in two immortalized mammary epithelial cell lines. In triple-negative breast cancer (TNBC) models, RBMS3 was necessary for maintaining the mesenchymal phenotype and invasion and migration in vitro. Loss of RBMS3 significantly impaired both tumor progression and spontaneous metastasis in vivo. Using a genome-wide approach to interrogate mRNA stability, we found that ectopic expression of RBMS3 upregulates many genes that are resistant to degradation following transcriptional blockade by actinomycin D (ACTD). Specifically, RBMS3 was shown to interact with the mRNA of EMT transcription factor PRRX1 and promote PRRX1 mRNA stability. PRRX1 is required for RBMS3-mediated EMT and is partially sufficient to rescue the effect of RBMS3 knockdown in TNBC cell lines. Together, this study identifies RBMS3 as a novel and common effector of EMT, which could be a promising therapeutic target for TNBC treatment.

New insights into the role and origin of pituitary S100β-positive cells

In the anterior pituitary, S100β protein (S100β) has been assumed to be a marker of folliculo-stellate cells, which are one of the non-hormone-producing cells existing in the parenchyma of the adult anterior lobe and are composed of subpopulations with various functions. However, recent accumulating studies on S100β-positive cells, including non-folliculo-stellate cells lining the marginal cell layer (MCL), have shown the novel aspect that most S100β-positive cells in the MCL and parenchyma of the adult anterior lobe are positive for sex determining region Y-box 2 (SOX2), a marker of pituitary stem/progenitor cells. From the viewpoint of SOX2-positive cells, the majority of these cells in the MCL and in the parenchyma are positive for S100β, suggesting that S100β plays a role in the large population of stem/progenitor cells in the anterior lobe of the adult pituitary. Reportedly, S100β/SOX2-double positive cells are able to differentiate into hormone-producing cells and various types of non-hormone-producing cells. Intriguingly, it has been demonstrated that extra-pituitary lineage cells invade the pituitary gland during prenatal pituitary organogenesis. Among them, two S100β-positive populations have been identified: one is SOX2-positive population which invades at the late embryonic period through the pituitary stalk and another is a SOX2-negative population that invades at the middle embryonic period through Atwell's recess. These two populations are likely the substantive origin of S100β-positive cells in the postnatal anterior pituitary, while S100β-positive cells emerging from oral ectoderm-derived cells remain unclear.

RUFY3 promotes the progression of hepatocellular carcinoma through activating NF-κB-mediated epithelial-mesenchymal transition

RUFY3 (RUN and FYVE domain-containing protein 3) has been demonstrated to exhibit carcinogenic effect in multiple malignancies. However, the exact role of RUFY3 in hepatocellular carcinoma (HCC) progression remains elusive. Herein, we aimed to identify the role and the underlying mechanism of RUFY3 in HCC progression. The RUFY3 levels in HCC specimens were detected by qRT-PCR, western blot, and immunohistochemistry, and its clinical significance in HCC patients was assessed. The effect of RUFY3 on HCC cell growth, migration, and invasion was explored by CCK-8 assay, wound healing assay, and transwell migration and invasion assays in vitro. The effect of RUFY3 on HCC cell growth and metastasis was also conducted in vivo through establishing xenograft tumor and lung metastatic mice model. The underlying mechanism responsible for RUFY3-induced HCC cell behavior was also investigated. Our results indicated that high levels of RUFY3 significantly correlated with tumor size, microvascular invasion, clinical stage, and poor prognosis for HCC patients. In addition, RUFY3 facilitated HCC cell growth, invasion, and metastasis both in vitro and in vivo through activating nuclear factor-κ-gene binding (NF-κB)-mediated epithelial-mesenchymal transition (EMT). Taken together, our results revealed that RUFY3 accelerated HCC progression via driving NF-κB-mediated EMT, suggesting a novel target for HCC treatment.

MD2 blockage prevents the migration and invasion of hepatocellular carcinoma cells via inhibition of the EGFR signaling pathway

BACKGROUND

The toll-like receptor (TLR) is an emerging signaling pathway in tumor invasion and metastasis. The activation of TLRs requires specific accessory proteins, such as the small secreted glycoprotein myeloid differentiation protein 2 (MD2), which contributes to ligand responsiveness. However, the role of MD2 in tumorigenesis and metastasis has rarely been reported. This study aimed to investigate the effects and underlying mechanisms of MD2 on the proliferation, migration, and invasion of hepatocellular carcinoma (HCC).

METHODS

Cell counting kit 8 (CCK8), cell colony formation, wound healing, and transwell assays were conducted to determine cell viability, proliferation, migration, and invasion, respectively. Quantitative real-time PCR (qRT-PCR) was performed to assess the expression of MD2 in HCC cell lines and human normal liver cell lines as well as the silencing efficiency of MD2 blockage. Western blot and qRT-PCR assays were performed to detect the protein and mRNA expression levels of epithelial mesenchymal transformation (EMT) markers and epidermal growth factor receptor (EGFR) signaling molecules.

RESULTS

MD2 was highly expressed in HCC tissues and cell lines. High expression of MD2 was associated with poor prognosis of HCC patients. In addition, MD2 silencing slightly inhibited the proliferation of HepG2 and HCCLM3, and significantly suppressed cell migration and invasion. Furthermore, MD2 blockage could distinctly prevent the EMT process by increasing the protein and mRNA levels of E-cadherin and Occludin, and decreasing the levels of Vimentin, N-cadherin, and Snail. Finally, the phosphorylation level of EGFR as well as its downstream molecular Src, Akt, I-κBα, and p65 were downregulated in HCC cells with MD2 silencing.

CONCLUSIONS

Our findings suggest that high expression of MD2 may affect the EMT, migration, and invasion via modulation of the EGFR pathway in HCC cells.

Role of epithelial-mesenchymal transition in chemoresistance in pancreatic ductal adenocarcinoma

Pancreatic cancer (PC) is the seventh leading cause of cancer death worldwide. The vast majority of patients who have PC develop metastases, resulting in poor treatment effects. Although great progress in therapeutic approaches has been achieved in recent decades, extensive drug resistance still persists, representing a major hurdle to effective anticancer therapy for pancreatic ductal adenocarcinoma (PDAC). Therefore, there is an urgent need to better understand the drug resistance mechanisms and develop novel treatment strategies to improve patient outcomes. Numerous studies suggest that chemoresistance is closely related to epithelial-mesenchymal transition (EMT) of PDAC cells. Thus, this article summarizes the impact of EMT on PDAC from the perspective of chemotherapy resistance and discusses the possible novel applications of EMT inhibition to develop more effective drugs against PDAC.

Intracellular AGR2 transduces PGE2 stimuli to promote epithelial-mesenchymal transition and metastasis of colorectal cancer

Human anterior gradient homolog 2 (AGR2) reportedly acts as an oncogene in multiple types of cancers. As a secreted protein, the oncogenic roles of extracellular AGR2 have been the focus of the increasing number of studies. In contrast, the oncological functions of intracellular AGR2 (iAGR2) remain elusive. Here, we report that intracellular AGR2 (iAGR2) is sufficient to promote CRC metastasis. iAGR2 binds to KDEL receptors (KDELRs) via its KTEL motif to activate downstream Gs-PKA signaling. Activated PKA upregulates the expression of NF-κB subunit c-Rel (REL) and acetylates histone H3 at lysine 9 (H3K9ac) to promote the transcription of SNAIL and SLUG. AGR2 can be upregulated by prostaglandin E2 (PGE2) via EP4-PI3K-AKT pathway and is indispensable for PGE2-induced CRC metastasis. AGR2 knockdown enhances therapeutic effects of a COX-2 inhibitor, celecoxib, in CRC metastasis. Collectively, our study reveals a promoting role and molecular mechanisms of iAGR2 in CRC metastasis and uncovers a new tumor microenvironment signal regulating AGR2 expression, which may provide new targets for treating metastatic CRC.

NHERF4 hijacks Mas-mediated PLC/AKT signaling to suppress the invasive potential of clear cell renal cell carcinoma cells

The Mas receptor has been reported to promote migration and invasion of clear cell renal cell carcinoma (ccRCC) cells via Ang-(1-7)-dependent AKT signaling. However, the mechanism underlying the regulation of Mas function remains unknown. Here, eight PDZ domain-containing proteins were identified as Mas interactors using surface plasmon resonance (SPR) coupled to mass spectrometry (MS). NHERF4 was the only downregulated gene across multiple independent ccRCC datasets. GST pull-down and co-immunoprecipitation assays confirmed physical interaction between NHERF4 and Mas. Using NHERF4 overexpression and knockdown assays, we found that NHERF4 inhibited Mas-induced migration, invasion and in vivo metastasis of ccRCC cells. Mechanistically, NHERF4 suppressed Mas-stimulated AKT phosphorylation and the PLC/Ca²⁺ response. We further demonstrated that NHERF4 compromised Mas-mediated migration and invasion of ccRCC cells via regulation of the PLC/AKT signaling axis. Analysis of the ccRCC dataset revealed that low levels of NHERF4 expression were correlated with higher TNM stage, and independently predicted poor prognosis of ccRCC patients. Overall, our study identified NHERF4 as a novel regulator of ccRCC invasiveness, and a prognostic biomarker, which may be beneficial for determining optimal therapeutic strategies for ccRCC patients.

LRP4 promotes migration and invasion of gastric cancer under the regulation of microRNA-140-5p

BACKGROUND

Low-density lipoprotein receptor-related protein 4 (LRP4) has been reported to be implicated in multiple types of cancers. However, the significance of LRP4 in gastric cancer (GC) remains poorly elucidated. Therefore, it's urgent to investigate the importance and underlying mechanisms of LRP4 in GC.

OBJECTIVE

To investigate the clinical roles of LRP4 in GC.

METHODS

The LRP4 mRNA and miR-140-5p was measured by qRT-PCR. The protein expression was determined Western blot. Kaplan-Meier survival curves and Cox proportional hazard regression models were performed to evaluate prognosis.

RESULTS

We demonstrated that LRP4 mRNA and protein was up-regulated in GC tissues for the first time. Its high expression was significantly correlated with malignant clinical features including TNM stage and lymph-node metastasis and poor prognosis for GC patients. LRP4 promotes migration, invasion and epithelial-mesenchymal transition (EMT) progress of GC cells. Mechanically, LRP4 regulated PI3K/AKT in GC cells. AKT inhibitors reversed the effects of LRP4. Finally, LRP4 was regulated by miR-140-5p in GC.

CONCLUSIONS

Our findings showed that LRP4 has an important function in GC progression and promotes GC migration, invasion and EMT by regulating PI3K/AKT under regulation of miR-140-5p, providing a potential therapeutic target for GC.

In Vitro 3D Cultures to Model the Tumor Microenvironment

Simple Summary

Tumor stroma is known to significantly influence cancer initiation and progression. In the last decade, 3D cell cultures have shown potential in modeling the tumor microenvironment. This review summarizes the main features of current 3D models, shedding light on their importance in the study of cancer biology and treatment.

Abstract

It is now well established that the tumor microenvironment plays a key role in determining cancer growth, metastasis and drug resistance. Thus, it is fundamental to understand how cancer cells interact and communicate with their stroma and how this crosstalk regulates disease initiation and progression. In this setting, 3D cell cultures have gained a lot of interest in the last two decades, due to their ability to better recapitulate the complexity of tumor microenvironment and therefore to bridge the gap between 2D monolayers and animal models. Herein, we present an overview of the 3D systems commonly used for studying tumor–stroma interactions, with a focus on recent advances in cancer modeling and drug discovery and testing.

Lung Cancer Management with Silibinin: A Historical and Translational Perspective

The flavonolignan silibinin, the major bioactive component of the silymarin extract of Silybum marianum (milk thistle) seeds, is gaining traction as a novel anti-cancer therapeutic. Here, we review the historical developments that have laid the groundwork for the evaluation of silibinin as a chemopreventive and therapeutic agent in human lung cancer, including translational insights into its mechanism of action to control the aggressive behavior of lung carcinoma subtypes prone to metastasis. First, we summarize the evidence from chemically induced primary lung tumors supporting a role for silibinin in lung cancer prevention. Second, we reassess the preclinical and clinical evidence on the effectiveness of silibinin against drug resistance and brain metastasis traits of lung carcinomas. Third, we revisit the transcription factor STAT3 as a central tumor-cell intrinsic and microenvironmental target of silibinin in primary lung tumors and brain metastasis. Finally, by unraveling the selective vulnerability of silibinin-treated tumor cells to drugs using CRISPR-based chemosensitivity screenings (e.g., the hexosamine biosynthesis pathway inhibitor azaserine), we illustrate how the therapeutic use of silibinin against targetable weaknesses might be capitalized in specific lung cancer subtypes (e.g., KRAS/STK11 co-mutant tumors). Forthcoming studies should take up the challenge of developing silibinin and/or next-generation silibinin derivatives as novel lung cancer-preventive and therapeutic biomolecules.

Schisandrin B inhibits epithelial‑mesenchymal transition and stemness of large‑cell lung cancer cells and tumorigenesis in xenografts via inhibiting the NF‑κB and p38 MAPK signaling pathways

Lung cancer is one of the most common types of cancer in the world, resulting in numerous cancer‑associated deaths. The properties of cancer stem cells (CSCs) are important for the initiation and deterioration of lung cancer. Schisandrin B (SchB), an active compound extracted from Schisandra chinensis, exerts anticancer effects in various malignancies, including lung cancer. Nevertheless, the potential of SchB in epithelial‑mesenchymal transition (EMT) and CSC features of large‑cell lung cancer remains unclear. The present study established cancer stem‑like cells derived from large‑cell lung cancer cells, NCI‑H460 and H661, and revealed that SchB inhibited the viability of cancer stem‑like cells at concentrations of ≥40 µmol/l. Moreover, SchB prominently inhibited cell migration, invasion and EMT. Sphere‑forming assays and western blotting demonstrated that the stemness of cancer stem‑like cells was alleviated by SchB treatment. Mechanistically, the current findings revealed that SchB contributed to the suppression of the NF‑κB and p38 MAPK signaling pathways. Notably, further results revealed that the malignant behaviors of NCI‑H460‑CSCs induced by the activation of the NF‑κB and p38 MAPK signaling pathways were suppressed by SchB treatment. Consistently, the inhibitory role of SchB in EMT and CSC activities, as well as in the activation of the NF‑κB and p38 MAPK signaling pathways, was confirmed in vivo. In conclusion, the present study demonstrated that SchB exerted inhibitory effects on large‑cell lung cancer cells via targeting the NF‑κB and p38 MAPK signaling pathways, suggesting that SchB may act as a potential therapeutic drug for large‑cell lung cancer.

Precision Therapy for Mesothelioma: Feasibility and New Opportunities

Malignant pleural mesotheliomas (MPMs) are characterised by their wide variation in natural history, ranging from minimally to highly aggressive, associated with both interpatient and intra-tumour genomic heterogeneity. Recent insights into the nature of this genetic variation, the identification of drivers, and the emergence of novel strategies capable of targeting vulnerabilities that result from the inactivation of key tumour suppressors suggest that new approaches to molecularly strategy therapy for mesothelioma may be feasible.

Dual inhibition of MEK1/2 and MEK5 suppresses the EMT/migration axis in triple-negative breast cancer through FRA-1 regulation

Triple-negative breast cancer (TNBC) presents a clinical challenge due to the aggressive nature of the disease and a lack of targeted therapies. Constitutive activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway has been linked to chemoresistance and metastatic progression through distinct mechanisms, including activation of epithelial-to-mesenchymal transition (EMT) when cells adopt a motile and invasive phenotype through loss of epithelial markers (CDH1), and acquisition of mesenchymal markers (VIM, CDH2). Although MAPK/ERK1/2 kinase inhibitors (MEKi) are useful antitumor agents in a clinical setting, including the Food and Drug Administration (FDA)-approved MEK1,2 dual inhibitors cobimetinib and trametinib, there are limitations to their clinical utility, primarily adaptation of the BRAF pathway and ocular toxicities. The MEK5 (HGNC: MAP2K5) pathway has important roles in metastatic progression of various cancer types, including those of the prostate, colon, bone and breast, and elevated levels of ERK5 expression in breast carcinomas are linked to a worse prognoses in TNBC patients. The purpose of this study is to explore MEK5 regulation of the EMT axis and to evaluate a novel pan-MEK inhibitor on clinically aggressive TNBC cells. Our results show a distinction between the MEK1/2 and MEK5 cascades in maintenance of the mesenchymal phenotype, suggesting that the MEK5 pathway may be necessary and sufficient in EMT regulation while MEK1/2 signaling further sustains the mesenchymal state of TNBC cells. Furthermore, additive effects on MET induction are evident through the inhibition of both MEK1/2 and MEK5. Taken together, these data demonstrate the need for a better understanding of the individual roles of MEK1/2 and MEK5 signaling in breast cancer and provide a rationale for the combined targeting of these pathways to circumvent compensatory signaling and subsequent therapeutic resistance.

Cytoskeletal Dynamics in Epithelial-Mesenchymal Transition: Insights into Therapeutic Targets for Cancer Metastasis

In cancer cells, a vital cellular process during metastasis is the transformation of epithelial cells towards motile mesenchymal cells called the epithelial to mesenchymal transition (EMT). The cytoskeleton is an active network of three intracellular filaments: actin cytoskeleton, microtubules, and intermediate filaments. These filaments play a central role in the structural design and cell behavior and are necessary for EMT. During EMT, epithelial cells undergo a cellular transformation as manifested by cell elongation, migration, and invasion, coordinated by actin cytoskeleton reorganization. The actin cytoskeleton is an extremely dynamic structure, controlled by a balance of assembly and disassembly of actin filaments. Actin-binding proteins regulate the process of actin polymerization and depolymerization. Microtubule reorganization also plays an important role in cell migration and polarization. Intermediate filaments are rearranged, switching to a vimentin-rich network, and this protein is used as a marker for a mesenchymal cell. Hence, targeting EMT by regulating the activities of their key components may be a potential solution to metastasis. This review summarizes the research done on the physiological functions of the cytoskeleton, its role in the EMT process, and its effect on multidrug-resistant (MDR) cancer cells-highlight some future perspectives in cancer therapy by targeting cytoskeleton.

Tumor Immune Microenvironment during Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) has been shown to play a critical role in tumor development from initiation to metastasis. EMT could be regarded as a continuum, with intermediate hybrid epithelial and mesenchymal phenotypes having high plasticity. Classical EMT is characterized by the phenotype change of epithelial cells to cells with mesenchymal properties, but EMT is also associated with multiple other molecular processes, including tumor immune evasion. Some previous studies have shown that EMT is associated with the cell number of immunosuppressive cells, such as myeloid-derived suppressor cells, and the expression of immune checkpoints, such as programmed cell death-ligand 1, in several cancer types. At the molecular level, EMT transcriptional factors, including Snail, Zeb1, and Twist1, produce or attract immunosuppressive cells or promote the expression of immunosuppressive checkpoint molecules via chemokine production, leading to a tumor immunosuppressive microenvironment. In turn, immunosuppressive factors induce EMT in tumor cells. This feedback loop between EMT and immunosuppression promotes tumor progression. For therapy directly targeting EMT has been challenging, the elucidation of the interactive regulation of EMT and immunosuppression is desirable for developing new therapeutic approaches in cancer. The combination of immune checkpoint inhibitors and immunotherapy targeting immunosuppressive cells could be a promising therapy for EMT.

TGFβ signaling networks in ovarian cancer progression and plasticity

Epithelial ovarian cancer (EOC) is a leading cause of cancer-related death in women. Late-stage diagnosis with significant tumor burden, accompanied by recurrence and chemotherapy resistance, contributes to this poor prognosis. These morbidities are known to be tied to events associated with epithelial-mesenchymal transition (EMT) in cancer. During EMT, localized tumor cells alter their polarity, cell-cell junctions, cell-matrix interactions, acquire motility and invasiveness and an exaggerated potential for metastatic spread. Key triggers for EMT include the Transforming Growth Factor-β (TGFβ) family of growth factors which are actively produced by a wide array of cell types within a specific tumor and metastatic environment. Although TGFβ can act as either a tumor suppressor or promoter in cancer, TGFβ exhibits its pro-tumorigenic functions at least in part via EMT. TGFβ regulates EMT both at the transcriptional and post-transcriptional levels as outlined here. Despite recent advances in TGFβ based therapeutics, limited progress has been seen for ovarian cancers that are in much need of new therapeutic strategies. Here, we summarize and discuss several recent insights into the underlying signaling mechanisms of the TGFβ isoforms in EMT in the unique metastatic environment of EOCs and the current therapeutic interventions that may be relevant.

The role of epithelial-mesenchymal transition-regulating transcription factors in anti-cancer drug resistance

The complex orchestration of gene expression that mediates the transition of epithelial cells into mesenchymal cells is implicated in cancer development and metastasis. As the primary regulator of the process, epithelial-mesenchymal transition-regulating transcription factors (EMT-TFs) play key roles in metastasis. They are also highlighted in recent preclinical studies on resistance to cancer therapy. This review describes the role of three main EMT-TFs, including Snail, Twist1, and zinc-finger E homeobox-binding 1 (ZEB1), relating to drug resistance and current possible approaches for future challenges targeting EMT-TFs.

Irradiation-Induced Activated Microglia Affect Brain Metastatic Colonization of NSCLC Cells via miR-9/CDH1 Axis

BACKGROUND AND PURPOSE

Brain metastasis is among the leading causes of death in patients with non-small-cell lung cancer (NSCLC). Through yet unknown mechanisms, prophylactic cranial irradiation (PCI) can significantly decrease the incidence of brain metastases. Given that PCI probably exerts indirect anti-tumoral effects by turning cerebral "soil" unfavorable for the colonization of metastatic tumor "seeds". This study aims to reveal how PCI regulates the brain microenvironment conducing to a reduction in brain metastases.

MATERIALS AND METHODS

Key markers of M1/M2 microglia types and mesenchymal-to-epithelial transition (MET) were analyzed by qRT-PCR and Western Blot in vitro. The target miR-9 was obtained by miRNA array analysis and confirmed by qRT-PCR in microglia. We used miRTarBase and TargetScan to analyze the target genes of miR-9 and confirmed by luciferase activity assay. Anti-metastatic effects of irradiation on the brain were evaluated by intravital imaging using a brain metastatic A549-F3 cell line in a nude mouse model.

RESULTS

Irradiation induced M1 microglia activation, which inhibited the MET process of A549 cell lines. Furthermore, levels of miR-9 secreted by irradiated M1 microglia significantly increased and played a vital role in the inhibition of the A549 MET process by directly targeting CDH1, concurrently decreasing cell capacity for localization in the brain, thus reducing brain metastases.

CONCLUSION

We demonstrated that miR-9 secreted by irradiated M1-type microglia played an important role in modulating A549 cell lines into mesenchymal phenotype and further decreased their localization capabilities in the brain. Our findings signify the modulating effect of irradiation on metastatic soil and the cross-talk between tumour cells and the metastatic microenvironment; importantly, they provide new opportunities for effective anti-metastasis therapies, especially for brain metastasis patients.

EGCG Inhibits Adipose-Derived Mesenchymal Stem Cells Differentiation into Adipocytes and Prevents a STAT3-Mediated Paracrine Oncogenic Control of Triple-Negative Breast Cancer Cell Invasive Phenotype

Obese subjects have an increased risk of developing triple-negative breast cancer (TNBC), in part associated with the chronic low-grade inflammation state. On the other hand, epidemiological data indicates that increased consumption of polyphenol-rich fruits and vegetables plays a key role in reducing incidence of some cancer types. Here, we tested whether green tea-derived epigallocatechin-3-gallate (EGCG) could alter adipose-derived mesenchymal stem cell differentiation into adipocytes, and how this impacts the secretome profile and paracrine regulation of the TNBC invasive phenotype. Here, cell differentiation was performed and conditioned media (CM) from preadipocytes and mature adipocytes harvested. Human TNBC-derived MDA-MB-231 real-time cell migration was performed using the exCELLigence system. Differential gene arrays and RT-qPCR were used to assess gene expression levels. Western blotting was used to assess protein expression and phosphorylation status levels. In vitro vasculogenic mimicry (VM) was assessed with Matrigel. EGCG was found to inhibit the induction of key adipogenic biomarkers, including lipoprotein lipase, adiponectin, leptin, fatty acid synthase, and fatty acid binding protein 4. Increased TNBC-derived MDA-MB-231 cell chemotaxis and vasculogenic mimicry were observed in response to mature adipocytes secretome, and this was correlated with increased STAT3 phosphorylation status. This invasive phenotype was prevented by EGCG, the JAK/STAT inhibitors Tofacitinib and AG490, as well as upon STAT3 gene silencing. In conclusion, dietary catechin-mediated interventions could, in part through the inhibition of adipogenesis and modulation of adipocytes secretome profile, prevent the onset of an obesogenic environment that favors TNBC development.

The role of miR-200b/c in balancing EMT and proliferation revealed by an activity reporter

Since their discovery, microRNAs (miRNAs) have been widely studied in almost every aspect of biology and medicine, leading to the identification of important gene regulation circuits and cellular mechanisms. However, investigations are generally focused on the analysis of their downstream targets and biological functions in overexpression and knockdown approaches, while miRNAs endogenous levels and activity remain poorly understood. Here, we used the cellular plasticity-regulating process of epithelial-to-mesenchymal transition (EMT) as a model to show the efficacy of a fluorescent sensor to separate cells with distinct EMT signatures, based on miR-200b/c activity. The system was further combined with a CRISPR-Cas9 screening platform to unbiasedly identify miR-200b/c upstream regulating genes. The sensor allows to infer miRNAs fundamental biological properties, as profiling of sorted cells indicated miR-200b/c as a molecular switch between EMT differentiation and proliferation, and suggested a role for metabolic enzymes in miR-200/EMT regulation. Analysis of miRNAs endogenous levels and activity for in vitro and in vivo applications could lead to a better understanding of their biological role in physiology and disease.

TDO2 Promotes the EMT of Hepatocellular Carcinoma Through Kyn-AhR Pathway

Tryptophan 2,3-dioxygenase (TDO2), an enzyme involved in tryptophan (Trp) metabolism has been linked with some malignant traits of various cancers. Kyn, the main product of Trp metabolism pathway catalyzed by TDO2 and indoleamine 2,3-dioxygenase (IDO) in tumor cells, was also demonstrated to activate aryl hydrocarbon receptor (AhR), which may regulate cancer growth and invasion in some malignancies. However, whether TDO2 participates in the metastasis and invasion of HCC has not been explored before. The underlying mechanism played by TDO2 in this process still requires further investigation. Here, we demonstrated that overexpression of TDO2 correlates with advanced stage or malignant traits in HCC patients. Knockdown or inhibition of TDO2 suppressed the migration and invasion of HCC cells in vitro and in vivo. Epithelial to mesenchymal transition (EMT) is an essential program happened in the initial phase of cancer metastasis. We found that in HCC cells, TDO2 promoted the EMT process evidenced by altered levels of biomarkers for EMT. Mechanically, TDO2 regulated the Kyn production in HCC cell via activated aryl hydrocarbon receptor (AhR). Together, these results indicate that TDO2 promotes the EMT of hepatocellular carcinoma through activating Kyn-AhR pathway, thereby participating in the metastasis and invasion of HCC.

Epithelial-Mesenchymal Transition (EMT) as a Therapeutic Target

Metastasis is the spread of cancer cells from the primary tumour to distant sites and organs throughout the body. It is the primary cause of cancer morbidity and mortality, and is estimated to account for 90% of cancer-related deaths. During the initial steps of the metastatic cascade, epithelial cancer cells undergo an epithelial-mesenchymal transition (EMT), and as a result become migratory and invasive mesenchymal-like cells while acquiring cancer stem cell properties and therapy resistance. As EMT is involved in such a broad range of processes associated with malignant transformation, it has become an increasingly interesting target for the development of novel therapeutic strategies. Anti-EMT therapeutic strategies could potentially not only prevent the invasion and dissemination of cancer cells, and as such prevent the formation of metastatic lesions, but also attenuate cancer stemness and increase the effectiveness of more classical chemotherapeutics. In this review, we give an overview about the pros and cons of therapies targeting EMT and discuss some already existing candidate drug targets and high-throughput screening tools to identify novel anti-EMT compounds.

Catechol enhances chemo‑ and radio‑sensitivity by targeting AMPK/Hippo signaling in pancreatic cancer cells

Overcoming chemo‑ and radio‑resistance is a major challenge in pancreatic cancer treatment. Therefore, there is an urgent need to discover novel therapeutic approaches to avoid chemo‑ and radio‑resistance in pancreatic cancer. Catechol is a phytochemical found in some fruits and vegetables. A few studies have reported on the potential anticancer effects of pure catechol. The present study aimed to explore the chemo‑ and radio‑sensitizing effects of catechol in Panc‑1 human pancreatic cancer cells. The effects of catechol on Panc‑1 cell proliferation, clonogenic survival, invasion, and migration were assessed using MTT, cell migration, and Transwell invasion assays. The chemo‑ and radio‑sensitizing effects of catechol on Panc‑1 cells were evaluated via MTT assay and flow cytometry. Western blotting was conducted to analyze the expression of proteins involved in several mechanisms induced by catechol in Panc‑1 cells, including growth inhibition, apoptosis, suppression of epithelial‑mesenchymal transition (EMT), and chemo‑ and radio‑sensitizing activities. The results indicated that catechol inhibited proliferation, promoted apoptosis, and suppressed cell migration, invasion, and EMT in Panc‑1 cells in a dose‑dependent manner. Catechol treatment also induced the phosphorylation of AMP‑activated protein kinase (AMPK) with a concomitant reduction in the expression of Hippo signaling pathway components, including Yes‑associated protein, cysteine‑rich angiogenic inducer 61, and connective tissue growth factor. In addition, catechol enhanced the chemosensitivity of Panc‑1 cells to gemcitabine, a commonly used chemotherapy in pancreatic cancer treatment. A combination of catechol and radiation enhanced apoptosis and increased the expression of two radiation‑induced DNA damage markers, p‑ATM and p‑Chk2. Collectively, the present results demonstrated that catechol, a naturally occurring compound, could suppress the proliferation of pancreatic cancer cells, reduce the expression of EMT‑related proteins, and enhance the chemo‑ and radio‑sensitivity of Panc‑1 cells by targeting AMPK/Hippo signaling.

Cytokine-chemokine network driven metastasis in esophageal cancer; promising avenue for targeted therapy

Esophageal cancer (EC) is a disease often marked by aggressive growth and poor prognosis. Lack of targeted therapies, resistance to chemoradiation therapy, and distant metastases among patients with advanced disease account for the high mortality rate. The tumor microenvironment (TME) contains several cell types, including fibroblasts, immune cells, adipocytes, stromal proteins, and growth factors, which play a significant role in supporting the growth and aggressive behavior of cancer cells. The complex and dynamic interactions of the secreted cytokines, chemokines, growth factors, and their receptors mediate chronic inflammation and immunosuppressive TME favoring tumor progression, metastasis, and decreased response to therapy. The molecular changes in the TME are used as biological markers for diagnosis, prognosis, and response to treatment in patients. This review highlighted the novel insights into the understanding and functional impact of deregulated cytokines and chemokines in imparting aggressive EC, stressing the nature and therapeutic consequences of the cytokine-chemokine network. We also discuss cytokine-chemokine oncogenic potential by contributing to the Epithelial-Mesenchymal Transition (EMT), angiogenesis, immunosuppression, metastatic niche, and therapeutic resistance development. In addition, it discusses the wide range of changes and intracellular signaling pathways that occur in the TME. Overall, this is a relatively unexplored field that could provide crucial insights into tumor immunology and encourage the effective application of modulatory cytokine-chemokine therapy to EC.

BASP1 Suppresses Cell Growth and Metastasis through Inhibiting Wnt/β-Catenin Pathway in Gastric Cancer

Objective

Our research is designed to explore the function of brain acid soluble protein 1 (BASP1) in the progression of gastric cancer (GC) and its underlying molecular mechanisms.

Methods

In this study, the expression of BASP1 was detected by quantitative real-time polymerase chain reaction (qRT-PCR) in both GC tissue and GC cells. The cell cloning, proliferation, apoptosis, migration, and invasion potential of AGS and HGC-27 cells were, respectively, determined using colony formation assay, 5-ethynyl-20-deoxyuridine (EDU) assay, flow cytometry, and Transwell assay. The protein expressions of Bax, caspase-3, Bcl-2, matrix metalloproteinases 2 (MMP-2), MMP-9, Wilms tumor 1 (WT1), Wnt, and β-catenin in AGS and HGC-27 cells were measured by western blot. In addition, the mRNA expressions of WT1, Wnt, and β-catenin in AGS and HGC-27 cells were detected by qRT-PCR.

Results

BASP1 expression was significantly downregulated in both GC tissue and GC cells. BASP1 overexpression markedly repressed proliferation, migration, and invasion and facilitated apoptosis in AGS and HGC-27 cells. In addition, BASP1 overexpression notably promoted the protein expression of Bax and caspase-3 in AGS and HGC-27 cells and inhibited the expression of Bcl-2, MMP-2, and MMP-9. Moreover, BASP1 overexpression significantly inhibited the mRNA and protein expression of WT1, Wnt, and β-catenin in AGS and HGC-27 cells.

Conclusion

BASP1 could significantly suppress cell proliferation, migration, and invasion and promote apoptosis through inhibiting the activation of the Wnt/β-catenin pathway in GC.

Long non-coding RNA GClnc1 knockdown suppresses progression of epithelial ovarian cancer by recruiting FOXC2 to disrupt the NOTCH1/NF-κB/Snail pathway

PURPOSE

Epithelial ovarian cancer (EOC) is a highly fatal gynecological cancer. A long noncoding RNA (lncRNA) gastric cancer-associated lncRNA1 (GClnc1) has been revealed to play critical roles in metastasis. Therefore, the present study aims to explore the correlation between GClnc1 and the metastasis and progression of EOC.

METHODS

First, 57 paired EOC and paracancerous tissues were collected to detect GClnc1 expression by RT-qPCR. Subsequently, OVC1 and SKOV3 cells with GClnc1 silencing/overexpression were developed to detect changes in cell activity, apoptosis, migration and invasion abilities. Then, the subcellular localization of GClnc1 was detected by nuclear/cytoplasmic fractionation, ISH and FISH assays. The binding relationships between GClnc1 and forkhead box protein C2 (FOXC2), and between FOXC2 and NOTCH1 were predicted and verified.

RESULTS

GClnc1 was significantly overexpressed in EOC tissues, and knockdown of GClnc1 inhibited cell viability and promoted apoptosis. Moreover, GClnc1 in the nucleus bound to the transcription factor FOXC2, thereby activating the transcription of NOTCH1. NOTCH1 overexpression enhanced the proliferation and epithelial-mesenchymal transition of SKOV3 and OVC1 cells. Moreover, NOTCH1 activated the NF-κB/Snail signaling. Finally, in vivo experiments demonstrated that GClnc1 knockdown suppressed the growth and metastasis of SKOV3 and OVC1 cells in vivo.

CONCLUSIONS

GClnc1 promoted NOTCH1 transcription by recruiting FOXC2, thereby activating the NF-κB/Snail signaling and promoting EOC cell growth and metastasis.

Identification of 9-Gene Epithelial-Mesenchymal Transition Related Signature of Osteosarcoma by Integrating Multi Cohorts

BACKGROUND

The prognosis of patients with osteosarcoma is still poor due to the lack of effective prognostic markers. The EMT (epithelial-mesenchymal transition) serves as a promoter in the progression of osteosarcoma. This study systematically analyzed EMT-related genes to explore new markers for predicting the prognosis of osteosarcoma.

METHODS

RNA-Seq data and clinical information were obtained from the GEO database; GSVA and GSEA analysis were used to enrich pathways related to osteosarcoma progression; LASSO method analysis was used to construct the prognosis risk signature. The "Nomogram" package generated the risk prediction nomogram, and its clinical applicability was evaluated by decision curve analysis (DCA).

RESULTS

GSVA and GSEA analysis showed that the EMT signaling pathway was closely related to osteosarcoma progression. A 9-genes signature (LAMA3, LGALS1, SGCG, VEGFA, WNT5A, MATN3, ANPEP, FUCA1, and FLNA) was constructed. The overall survival (OS) of the high-risk scores group was significantly lower than the low-risk scores group. The 9-gene signature demonstrated good predictive accuracy. Cox regression analysis showed that the 9-gene signature provided independent prognostic factors for osteosarcoma patients. In addition, the predictive nomogram model could effectively predict the prognosis of osteosarcoma patients.

CONCLUSION

This study constructed a 9-gene signature as a new prognostic marker to predict osteosarcoma patients' survival.

Erythrocyte membrane protein band 4.1-like 3 inhibits osteosarcoma cell invasion through regulation of Snai1-induced epithelial-to-mesenchymal transition

Erythrocyte membrane protein band 4.1-like 3 (EPB41L3) is an important membrane skeletal protein that may interact with numerous membrane proteins. Loss of EPB41L3 is reported in multiple cancer types, and it is originally identified as a tumor suppressor. In this study, through analyzing expression profiling retrieved from the Gene Expression Omnibus (GEO) dataset, we find that EPB41L3 is upregulated in primary osteosarcoma (OS) and osteosarcoma cell lines. Importantly, EPB41L3 may promote osteosarcoma cell proliferation and suppress osteosarcoma cell migration and invasion. Reduced EPB41L3 leads to a decrease of E-cadherin as well as an increase of N-cadherin and Vimentin, implying a prominent epithelial-to-mesenchymal transition. Furthermore, we demonstrate that EPB41L3 inhibits the epithelial-to-mesenchymal transition through destabilizing the Snai1 protein, one of the most important transcription factors of the epithelial-to-mesenchymal transition process. Collectively, our study has first established the complex and vital roles of EPB41L3 and implicated EPB41L3 as a potential biomarker in osteosarcoma.

Activation of the Ion Channel TRPV4 Induces Epithelial to Mesenchymal Transition in Breast Cancer Cells

Epithelial to mesenchymal transition (EMT) in cancer is important in therapeutic resistance and invasiveness. Calcium signaling is key to the induction of EMT in breast cancer cells. Although inhibition of specific calcium-permeable ion channels regulates the induction of a sub-set of EMT markers in breast cancer cells, it is still unclear if activation of a specific calcium channel can be a driver for the induction of EMT events. In this study, we exploited the availability of a selective pharmacological activator of the calcium-permeable ion channel TRPV4 to assess the direct role of calcium influx in EMT marker induction. Gene association studies revealed a link between TRPV4 and gene-ontologies associated with EMT and poorer relapse-free survival in lymph node-positive basal breast cancers. TRPV4 was an important component of the calcium influx phase induced in MDA-MB-468 breast cancer cells by the EMT inducer epidermal growth factor (EGF). Pharmacological activation of TRPV4 then drove the induction of a variety of EMT markers in breast cancer cells. These studies demonstrate that calcium influx through specific pathways appears to be sufficient to trigger EMT events.

HDAC2 inhibits EMT-mediated cancer metastasis by downregulating the long noncoding RNA H19 in colorectal cancer

BACKGROUND

Emerging evidence suggests that epithelial mesenchymal transition (EMT) and epigenetic mechanisms promote metastasis. Histone deacetylases (HDACs) and noncoding RNAs (ncRNAs) are important epigenetic regulators. Here, we elucidated a novel role of histone deacetylase 2 (HDAC2) in regulating EMT and CRC metastasis via ncRNA.

METHODS

The expression of HDACs in CRC was analyzed using the public databases and matched primary and metastatic tissues, and CRC cells with different metastatic potentials (DLD1, HCT116, SW480 and SW620). Microarray analysis was used to identify differential genes in parental and HDAC2 knockout CRC cells. EMT and histone modifications were determined using western blot and immunofluorescence. Migration ability was assessed by transwell assay, and metastasis was assessed in vivo using a tail vain injection. Gene expression and regulation was assessed by RT-PCR, chromatin immunoprecipitation and reporter assays. Protein interaction was assessed by immunoprecipitation. Specific siRNAs targeting H19, SP1 and MMP14 were used to validate their role in HDAC2 loss induced EMT and metastasis.

RESULTS

Reduced HDAC2 expression was associated with poor prognosis in CRC patients and found in CRC metastasis. HDAC2 deletion or knockdown induced EMT and metastasis by upregulating the long noncoding RNA H19 (LncRNA H19). HDAC2 inhibited LncRNA H19 expression by histone H3K27 deacetylation in its promoter via binding with SP1. LncRNA H19 functioned as a miR-22-3P sponge to increase the expression of MMP14. HDAC2 loss strongly promoted CRC lung metastasis, which was suppressed LncRNA H19 knockdown.

CONCLUSION

Our study supports HDAC2 as a CRC metastasis suppressor through the inhibition of EMT and the expression of H19 and MMP14.

Novel diphenyl urea derivative serves as an inhibitor on human lung cancer cell migration by disrupting EMT via Wnt/β-catenin and PI3K/Akt signaling

Targeted anti-tumor small molecules are considered to be promising candidates for cancer treatment. The novel diphenyl urea derivative (DUD) was synthesized by the molecular docking based on the structure optimization of Taspine (a natural product). In this study, we explored the anti-metastatic potential of DUD for NSCLC in vitro. DUD significantly suppressed A549 cell migration by reversing EMT. The inhibition was reflected on upregulation of E-cadherin and downregulation of N-cadherin, vimentin, Snail and HIF-1α. Meanwhile, DUD inhibited the β-catenin nuclear translocation by upregulating Axin and downregulating the expression of APC, CK1 and phosphorylation of GSK3β, and simultaneously decreasing MMP9 and MMP13 expression. Moreover, it was associated with the downregulation of the PI3K/Akt/mTOR signaling. Furthermore, we used XAV939, an β-catenin inhibitor, to verify the mechanism of DUD. These results suggested that DUD inhibited A549 cells migration by reversing EMT via Wnt/β-catenin and PI3K/Akt signaling. DUD might be a potential therapeutic drug candidate for NSCLC treatment.