The NOTCH4-HEY1 Pathway Induces Epithelial-Mesenchymal Transition in Head and Neck Squamous Cell Carcinoma

Latest insights into the global epidemiological features, screening, early diagnosis and prognosis prediction of esophageal squamous cell carcinoma

As a highly invasive carcinoma, esophageal cancer (EC) was the eighth most prevalent malignancy and the sixth leading cause of cancer-related death worldwide in 2020. Esophageal squamous cell carcinoma (ESCC) is the major histological subtype of EC, and its incidence and mortality rates are decreasing globally. Due to the lack of specific early symptoms, ESCC patients are usually diagnosed with advanced-stage disease with a poor prognosis, and the incidence and mortality rates are still high in many countries, especially in China. Therefore, enormous challenges still exist in the management of ESCC, and novel strategies are urgently needed to further decrease the incidence and mortality rates of ESCC. Although the key molecular mechanisms underlying ESCC pathogenesis have not been fully elucidated, certain promising biomarkers are being investigated to facilitate clinical decision-making. With the advent and advancement of high-throughput technologies, such as genomics, proteomics and metabolomics, valuable biomarkers with high sensitivity, specificity and stability could be identified for ESCC. Herein, we aimed to determine the epidemiological features of ESCC in different regions of the world, especially in China, and focused on novel molecular biomarkers associated with ESCC screening, early diagnosis and prognosis prediction.

Notch signaling pathway in cancer: from mechanistic insights to targeted therapies

Notch signaling, renowned for its role in regulating cell fate, organ development, and tissue homeostasis across metazoans, is highly conserved throughout evolution. The Notch receptor and its ligands are transmembrane proteins containing epidermal growth factor-like repeat sequences, typically necessitating receptor-ligand interaction to initiate classical Notch signaling transduction. Accumulating evidence indicates that the Notch signaling pathway serves as both an oncogenic factor and a tumor suppressor in various cancer types. Dysregulation of this pathway promotes epithelial-mesenchymal transition and angiogenesis in malignancies, closely linked to cancer proliferation, invasion, and metastasis. Furthermore, the Notch signaling pathway contributes to maintaining stem-like properties in cancer cells, thereby enhancing cancer invasiveness. The regulatory role of the Notch signaling pathway in cancer metabolic reprogramming and the tumor microenvironment suggests its pivotal involvement in balancing oncogenic and tumor suppressive effects. Moreover, the Notch signaling pathway is implicated in conferring chemoresistance to tumor cells. Therefore, a comprehensive understanding of these biological processes is crucial for developing innovative therapeutic strategies targeting Notch signaling. This review focuses on the research progress of the Notch signaling pathway in cancers, providing in-depth insights into the potential mechanisms of Notch signaling regulation in the occurrence and progression of cancer. Additionally, the review summarizes pharmaceutical clinical trials targeting Notch signaling for cancer therapy, aiming to offer new insights into therapeutic strategies for human malignancies.

Modulation of Epithelial-Mesenchymal Transition Is a Possible Underlying Mechanism for Inducing Chemoresistance in MIA PaCa-2 Cells against Gemcitabine and Paclitaxel

To elucidate the currently unknown molecular mechanisms responsible for the similarity and difference during the acquirement of resistance against gemcitabine (GEM) and paclitaxel (PTX) in patients with pancreatic carcinoma, we examined two-dimensional (2D) and three-dimensional (3D) cultures of parent MIA PaCa-2 cells (MIA PaCa-2-PA) and their GEM resistance cell line (MIA PaCa-2-GR) and PTX resistance (MIA PaCa-2-PR). Using these cells, we examined 3D spheroid configurations and cellular metabolism, including mitochondrial and glycolytic functions, with a Seahorse bio-analyzer and RNA sequencing analysis. Compared to the MIA PaCa-2-PA, (1) the formation of the 3D spheroids of MIA PaCa-2-GR or -PR was much slower, and (2) their mitochondrial and glycolytic functions were greatly modulated in MIA PaCa-2-GR or -PR, and such metabolic changes were also different between their 2D and 3D culture conditions. RNA sequencing and bioinformatic analyses of the differentially expressed genes (DEGs) using an ingenuity pathway analysis (IPA) suggested that various modulatory factors related to epithelial -mesenchymal transition (EMT) including STAT3, GLI1, ZNF367, NKX3-2, ZIC2, IFIT2, HEY1 and FBLX, may be the possible upstream regulators and/or causal network master regulators responsible for the acquirement of drug resistance in MIA PaCa-2-GR and -PR. In addition, among the prominently altered DEGs (Log2 fold changes more than 6 or less than -6), FABP5, IQSEC3, and GASK1B were identified as unique genes associated with their antisense RNA or pseudogenes, and among these, FABP5 and GASK1B are known to function as modulators of cancerous EMT. Therefore, the observations reported herein suggest that modulations of cancerous EMT may be key molecular mechanisms that are responsible for inducing chemoresistance against GEM or PTX in MIA PaCa-2 cells.

PXMP4 promotes gastric cancer cell epithelial-mesenchymal transition via the PI3K/AKT signaling pathway

BACKGROUND

Peroxisomal membrane protein 4 (PXMP4), a member of the peroxisome membrane protein PXMP2/4 family, participates in the progression of several malignant cancers. Nevertheless, the effect of PXMP4 in the development of gastric cancer (GC) is still unknown. As a result, the focus of this investigation was to elucidate the potential mechanisms of PXMP4 in GC.

METHODS AND RESULTS

Firstly, bioinformatics analysis results showed higher expression of PXMP4 in GC tissues. Secondly, clinical analysis of 57 patients with GC revealed correlations between PXMP4 expression and differentiation, depth of invasion, as well as TNM stage. Furthermore, individuals with elevated PXMP4 expression in GC exhibited an unfavorable prognosis. In vitro data showed the involvement of knockdown/overexpression of PXMP4 in the proliferation, invasion, and migration of GC cells, and triggering the epithelial-mesenchymal transition (EMT) of GC cells through the activation of the PI3K/AKT signaling pathway. LY294002, a PI3K/AKT inhibitor, inhibited the expression of PI3K/AKT-related proteins but did not affect the expression of PXMP4.

CONCLUSIONS

These findings indicate that PXMP4 potentially functions as an upstream molecule in the PI3K/AKT pathway, governing the EMT process in GC.

Molecular signaling in cancer stem cells of tongue squamous cell carcinoma: Therapeutic implications and challenges

Head and neck squamous cell carcinoma is the seventh most common cancer worldwide with high mortality rates. Amongst oral cavity cancers, tongue carcinoma is a very common and aggressive oral cavity carcinoma. Despite the implementation of a multimodality treatment regime including surgical intervention, chemo-radiation as well as targeted therapy, tongue carcinoma shows a poor overall 5-year survival pattern, which is attributed to therapy resistance and recurrence of the disease. The presence of a rare population, i.e., cancer stem cells (CSCs) within the tumor, are involved in therapy resistance, recurrence, and distant metastasis that results in poor survival patterns. Therapeutic agents targeting CSCs have been in clinical trials, although they are unable to reach into therapy stage which is due to their failure in trials. A more detailed understanding of the CSCs is essential for identifying efficient targets. Molecular signaling pathways, which are differentially regulated in the CSCs, are one of the promising targets to manipulate the CSCs that would provide an improved outcome. In this review, we summarize the current understanding of molecular signaling associated with the maintenance and regulation of CSCs in tongue squamous cell carcinoma in order to emphasize the need of the hour to get a deeper understanding to unravel novel targets.

The Clinical Application of Immunohistochemical Expression of Notch4 Protein in Patients with Colon Adenocarcinoma

The Notch signalling pathway is one of the most conserved and well-characterised pathways involved in cell fate decisions and the development of many diseases, including cancer. Among them, it is worth noting the Notch4 receptor and its clinical application, which may have prognostic value in patients with colon adenocarcinoma. The study was performed on 129 colon adenocarcinomas. Immunohistochemical and fluorescence expression of Notch4 was performed using the Notch4 antibody. The associations between the IHC expression of Notch4 and clinical parameters were analysed using the Chi² test or Chi²_Yatesa test. The Kaplan-Meier analysis and the log-rank test were used to verify the relationship between the intensity of Notch4 expression and the 5-year survival rate of patients. Intracellular localisation of Notch4 was detected by the use of the immunogold labelling method and TEM. 101 (78.29%) samples had strong Notch4 protein expression, and 28 (21.71%) samples were characterised by low expression. The high expression of Notch4 was clearly correlated with the histological grade of the tumour (p < 0.001), PCNA immunohistochemical expression (p < 0.001), depth of invasion (p < 0.001) and angioinvasion (p < 0.001). We can conclude that high expression of Notch4 is correlated with poor prognosis of colon adenocarcinoma patients (log-rank, p < 0.001).

Tumour microenvironment and aberrant signaling pathways in cisplatin resistance and strategies to overcome in oral cancer

OBJECTIVE

Oral cancer is the sixteenth most prevalent cancer in the world and the third-most in India. Despite of several treatment modalities, the cure rate of oral cancer is still low due to drug resistance mechanisms, which are caused by many reasons. It is necessary to improve the existing treatment strategies and discover neoteric therapy to kill cancer cells, which will give oral cancer's cure rate more success. So this review aims to delineate the molecular mechanisms behind cisplatin resistance, specifically the role of the tumor microenvironment, extracellular vesicles, and altered signaling pathways and its overcoming strategies in oral cancer.

DESIGN

This review was designed by searching words like cancer, oral cancer, cisplatin-resistance, tumor microenvironment, aberrant signalings, and extracellular vesicles, overcoming strategies for cisplatin resistance in databases like PubMed, Google Scholar, web science, and Scopus. Data available in this review is from 2017 to 2021.

RESULTS

After searching too much data, we found these 98 data appropriate for our review. From these data, we found that tumor microenvironment, extracellular vesicles, and altered signaling pathways like PI3K/AKT, EGFR, NOTCH, Ras, PTEN, Nf-κβ, and Wnt signaling have a crucial role in resistance development towards cisplatin in oral cancer.

CONCLUSIONS

Lastly, this review explores the alternative strategies to overcome cisplatin resistance likely, the combination therapy and targeted therapy by combining more than one chemotherapeutic drug or inhibitors of signaling pathways and also by using nanoparticle loaded drugs that will reduce the drug efflux, which gives new treatment strategies.

Cancer Cell De-Differentiation: Plasticity-Driven Stratagem For Tumor Metastasis and Recurrence

Tumor recurrence is a colossal challenge in clinical oncology. This multifactorial problem is attributed to the emergence of additional genetic mutations and the presence of dormant cancer cells. However, the plasticity of non-stem cancer cells and the acquisition of cancer stem cell (CSC) functionality is another contributing factor to tumor recurrence. Herein, I focus attention on the mechanisms that fuel cancer cell de-differentiation and the interplay between intra-cellular regulators and tumor microenvironment (TME) landscape that promotes cancer cell stemness. Our understanding of the mechanisms underlying tumor cell de-differentiation is crucial for developing innovative therapeutic strategies that prevent cancer from ever recurring.

Inactivation of Notch4 Attenuated Pancreatic Tumorigenesis in Mice

Expression of the Notch family of receptors is often upregulated in pancreatic ductal adenocarcinoma (PDAC). In this study, we focused on Notch4, which had not been investigated in PDAC. We generated KC (LSL-KrasG12D;p48-Cre), N4 - / - KC (Notch4- / -;LSL-KrasG12D;p48-Cre), PKC (p16fl/fl;LSL-KrasG12D;p48-Cre), and N4 - / - PKC (Notch4-/ -; p16fl/f l;LSL-KrasG12D;p48-Cre) genetically engineered mouse models (GEMM). We performed caerulein treatment in both KC and N4 - / - KC mice, and the development of acinar-to-ductal metaplasia (ADM) and pancreatic intraepithelial neoplasia (PanIN) lesions were significantly diminished in the N4 - / - KC than in the KC GEMM (P = 0.01). This in vivo result was validated by in vitro ADM induction of the explant cultures of pancreatic acinar cells from the N4 - / - KC and KC mice (P < 0.001), confirming that Notch4 is an important contributor to early pancreatic tumorigenesis. To evaluate the role of Notch4 in the later stage of pancreatic tumorigenesis, we compared the PKC and N4 - / - PKC mice. The N4 - / - PKC mice had better overall survival (P = 0.012) and significantly reduced tumor burden (PanIN: P = 0.018 at 2 months, PDAC: P = 0.039 at 5 months) compared with the PKC GEMM. RNA-sequencing analysis of pancreatic tumor cell lines derived from the PKC and N4 - / - PKC GEMMs revealed that 408 genes were differentially expressed (FDR < 0.05) and Pcsk5 is a potential downstream effector of the Notch4 signaling pathway (P < 0.001). Low expression of Pcsk5 positively correlates with good survival in patients with PDAC (P = 0.028). We have identified a novel role for Notch4 signaling with tumor-promoting function in pancreatic tumorigenesis. Our study also uncovered a novel association between Pcsk5 and Notch4 signaling in PDAC.

Significance

We demonstrated that global inactivation of Notch4 significantly improved the survival of an aggressive mouse model for PDAC and provided preclinical evidence that Notch4 and Pcsk5 are novel targets for PDAC therapies.

HEY1-mediated cisplatin resistance in lung adenocarcinoma via epithelial-mesenchymal transition

Lung cancer is one of the most common malignancies and the leading cause of cancer-related death in the world. In patients with advanced lung adenocarcinoma who are negative for driver gene mutations, platinum-based chemotherapy represented by cisplatin remain the standard of care. Therefore, studying the mechanism behind inevitable cisplatin resistance in lung adenocarcinoma is still important. In this study, the potentially related differential expression gene for cisplatin resistance in lung adenocarcinoma was screened in the GEO database. The expression level of HEY1 in cell lines of lung adenocarcinoma was detected and HEY1 expression was up-regulated in cisplatin-resistant lung adenocarcinoma tissues and cell lines A549/DDP. Patients with high HEY1 expression have poor prognosis after cisplatin therapy. Gain and loss function assays uncovered that HEY1 could regulate the cisplatin sensitivity of NSCLC cells. In vivo experiments have confirmed that silence of HEY1 expression can induce cisplatin resistance, and epithelial-mesenchymal transition (EMT) changes occur during this process. Mechanically, HEY1 silencing significantly up-regulated E-cadherin expression and down-regulated Vimentin in A549/DDP cells. While up-regulation of HEY1 resulted in down-regulation of E-cadherin and up-regulation of Vimentin in A549 cells. Immunohistochemical experiments confirmed that E-cadherin was significantly decreased, and Vimentin expression was significantly up-regulated in cisplatin-resistant lung adenocarcinoma tissues. HEY1 can mediate the occurrence of cisplatin-acquired resistance in lung adenocarcinoma, and the possible mechanism is to regulate the EMT. The results of this study can provide a new direction and target for clinical research on the reversal of cisplatin resistance in lung adenocarcinoma.

Genomic and Immune Approach in Platinum Refractory HPV-Negative Head and Neck Squamous Cell Carcinoma Patients Treated with Immunotherapy: A Novel Combined Profile

Introduction: Only a minority of patients with platinum refractory head and neck squamous cell carcinoma (PR/HNSCC) gain some lasting benefit from immunotherapy. Methods: The combined role of the comprehensive genomic (through the FoundationOne Cdx test) and immune profiles of 10 PR/HNSCC patients treated with the anti-PD-1 nivolumab was evaluated. The immune profiles were studied both at baseline and at the second cycle of immunotherapy, weighing 20 circulating cytokines/chemokines, adhesion molecules, and 14 soluble immune checkpoints dosed through a multiplex assay. A connectivity map was obtained by calculating the Spearman correlation between the expression profiles of circulating molecules. Results: Early progression occurred in five patients, each of them showing TP53 alteration and three of them showing a mutation/loss/amplification of genes involved in the cyclin-dependent kinase pathway. In addition, ERB2 amplification (1 patient), BRCA1 mutation (1 patient), and NOTCH1 genes alteration (3 patients) occurred. Five patients achieved either stable disease or partial response. Four of them carried mutations in PI3K/AKT/PTEN pathways. In the only two patients, with a long response to immunotherapy, the tumor mutational burden (TMB) was high. Moreover, a distinct signature, in terms of network connectivity of the circulating soluble molecules, characterizing responder and non-responder patients, was evidenced. Moreover, a strong negative and statistically significant (p-value ≤ 0.05) correlation with alive status was evidenced for sE-selectin at T1. Conclusions: Our results highlighted the complexity and heterogeneity of HNSCCs, even though it was in a small cohort. Molecular and immune approaches, combined in a single profile, could represent a promising strategy, in the context of precision immunotherapy.

Overcoming therapeutic resistance to platinum-based drugs by targeting Epithelial–Mesenchymal transition

Platinum-based drugs (PBDs), including cisplatin, carboplatin, and oxaliplatin, have been widely used in clinical practice as mainstay treatments for various types of cancer. Although there is firm evidence of notable achievements with PBDs in the management of cancers, the acquisition of resistance to these agents is still a major challenge to efforts at cure. The introduction of the epithelial-mesenchymal transition (EMT) concept, a critical process during embryonic morphogenesis and carcinoma progression, has offered a mechanistic explanation for the phenotypic switch of cancer cells upon PBD exposure. Accumulating evidence has suggested that carcinoma cells can enter a resistant state via induction of the EMT. In this review, we discussed the underlying mechanism of PBD-induced EMT and the current understanding of its role in cancer drug resistance, with emphasis on how this novel knowledge can be exploited to overcome PBD resistance via EMT-targeted compounds, especially those under clinical trials.

Link of sorafenib resistance with the tumor microenvironment in hepatocellular carcinoma: Mechanistic insights

Sorafenib, a multi-kinase inhibitor with antiangiogenic, antiproliferative, and proapoptotic properties, is the first-line treatment for patients with late-stage hepatocellular carcinoma (HCC). However, the therapeutic effect remains limited due to sorafenib resistance. Only about 30% of HCC patients respond well to the treatment, and the resistance almost inevitably happens within 6 months. Thus, it is critical to elucidate the underlying mechanisms and identify effective approaches to improve the therapeutic outcome. According to recent studies, tumor microenvironment (TME) and immune escape play critical roles in tumor occurrence, metastasis and anti-cancer drug resistance. The relevant mechanisms were focusing on hypoxia, tumor-associated immune-suppressive cells, and immunosuppressive molecules. In this review, we focus on sorafenib resistance and its relationship with liver cancer immune microenvironment, highlighting the importance of breaking sorafenib resistance in HCC.

Roles of Notch Signaling in the Tumor Microenvironment

The Notch signaling pathway is an architecturally simple signaling mechanism, well known for its role in cell fate regulation during organ development and in tissue homeostasis. In keeping with its importance for normal development, dysregulation of Notch signaling is increasingly associated with different types of tumors, and proteins in the Notch signaling pathway can act as oncogenes or tumor suppressors, depending on the cellular context and tumor type. In addition to a role as a driver of tumor initiation and progression in the tumor cells carrying oncogenic mutations, it is an emerging realization that Notch signaling also plays a role in non-mutated cells in the tumor microenvironment. In this review, we discuss how aberrant Notch signaling can affect three types of cells in the tumor stroma-cancer-associated fibroblasts, immune cells and vascular cells-and how this influences their interactions with the tumor cells. Insights into the roles of Notch in cells of the tumor environment and the impact on tumor-stroma interactions will lead to a deeper understanding of Notch signaling in cancer and inspire new strategies for Notch-based tumor therapy.

Transcription Factor HEY1 Improves Brain Vascular Endothelial Cell Function and Alleviates Ischemic Stroke by Upregulating NOTCH3

To investigate the function of hairy/enhancer-of-split related with YRPW motif protein 1 (HEY1) and Notch receptor 3 (NOTCH3) in ischemic stroke. Stroke models were established by middle cerebral artery occlusion (MCAO) and oxygen glucose deprivation (OGD) in rats and rat brain microvascular endothelial cells (BMVECs), respectively. Neurological deficit evaluation and 2,3,5-triphenyltetrazolium chloride staining were used to assess cerebral injury. The expression of HEY1 and NOTCH3 was manipulated using gain and loss of function approaches. Terminal deoxynucleotidyl transferase dUTP nick end labeling and Western blotting analysis of cleaved caspase-3 and B-cell lymphoma-2 (Bcl2) were used to evaluate apoptosis. Enzyme-linked immunosorbent assay was performed to measure the expression levels of interleukin (IL)-1β, IL-6 and IL-18. The proliferation and migration of BMVECs were analyzed by Ki-67 immunofluorescence and scratch assay, respectively. Tube formation assay was conducted to measure the length of capillary-like tubes formed by BMVECs. Co-immunoprecipitation was used to testify the relationship between HEY1 and NOTCH3. HEY1 and NOTCH3 were upregulated in MCAO and OGD models. HEY1 ameliorated ischemic injuries in MCAO rats. Knockdown of HEY1 or NOTCH3 promoted OGD-induced apoptosis and inflammation and inhibited proliferation and migration in BMVECs. NOTCH3 was a binding protein of HEY1. Overexpression of HEY1 offset the disease-promoting effect of NOTCH3 silencing. HEY1 suppresses apoptosis and inflammation and promotes proliferation and migration in BMVECs by upregulating NOTCH3, thereby ameliorating ischemic stroke.

FAS receptor regulates NOTCH activity through ERK-JAG1 axis activation and controls oral cancer stemness ability and pulmonary metastasis

Pulmonary metastasis occurring via the colonization of circulating cancer stem cells is a major cause of oral squamous cell carcinoma (OSCC)-related death. Thus, understanding the mechanism of OSCC pulmonary metastasis may provide a new opportunity for OSCC treatment. FAS, a well-known apoptosis-inducing death receptor, has multiple nonapoptotic, protumorigenic functions. Previously, we found that SAS OSCC cells with FAS receptor knockout did not affect orthotopic tumor growth or cervical lymph node metastasis. However, FAS knockout cells could not colonize in distant organs to form metastases upon intravenous injection, which hinted at the cancer stemness function of the FAS receptor. Immunohistochemistry staining indicated that the FAS receptor serves as a poor prognosis marker in OSCC patients. FAS knockout inhibited in vitro cancer spheroid formation, migration and invasion, and prevented mesenchymal transition in OSCC cells and inhibited OSCC pulmonary metastasis in vivo. To determine the regulatory mechanism by which the FAS receptor exerts its oncogenic function, we utilized cDNA microarrays and phosphoprotein arrays to discover key candidate genes and signaling pathway regulators. JAG1 expression and NOTCH pathway activation were controlled by the FAS receptor through ERK phosphorylation. Both JAG1 and NOTCH1 silencing decreased in vitro cancer spheroid formation. In OSCC cells, FAS ligand or JAG1 protein treatment increased NOTCH pathway activity, which could be abolished by FAS receptor knockout. In FAS knockout cells, restoring the NOTCH1 intracellular domain stimulated cancer spheroid formation. Both JAG1 and NOTCH1 silencing decreased in vivo OSCC growth. In conclusion, we found a novel FAS-ERK-JAG1-NOTCH1 axis that may contribute to OSCC stemness and pulmonary metastasis.

Advancement in Cancer Stem Cell Biology and Precision Medicine-Review Article Head and Neck Cancer Stem Cell Plasticity and the Tumor Microenvironment

Head and Neck cancer survival has continued to remain around 50% despite treatment advances. It is thought that cancer stem cells play a key role in promoting tumor heterogeneity, treatment resistance, metastasis, and recurrence in solid malignancies including head and neck cancer. Initial studies identified cancer stem cell markers including CD44 and ALDH in head and neck malignancies and found that these cells show aggressive features in both in vitro and in vivo studies. Recent evidence has now revealed a key role of the tumor microenvironment in maintaining a cancer stem cell niche and promoting cancer stem cell plasticity. There is an increasing focus on identifying and targeting the crosstalk between cancer stem cells and surrounding cells within the tumor microenvironment (TME) as new therapeutic potential, however understanding how CSC maintain a stem-like state is critical to understanding how to therapeutically alter their function. Here we review the current evidence for cancer stem cell plasticity and discuss how interactions with the TME promote the cancer stem cell niche, increase tumor heterogeneity, and play a role in treatment resistance.

Shooting at Moving and Hidden Targets-Tumour Cell Plasticity and the Notch Signalling Pathway in Head and Neck Squamous Cell Carcinomas

Head and Neck Squamous Cell Carcinoma (HNSCC) is often aggressive, with poor response to current therapies in approximately 40-50% of the patients. Current therapies are restricted to operation and irradiation, often combined with a small number of standard-of-care chemotherapeutic drugs, preferentially for advanced tumour patients. Only very recently, newer targeted therapies have entered the clinics, including Cetuximab, which targets the EGF receptor (EGFR), and several immune checkpoint inhibitors targeting the immune receptor PD-1 and its ligand PD-L1. HNSCC tumour tissues are characterized by a high degree of intra-tumour heterogeneity (ITH), and non-genetic alterations that may affect both non-transformed cells, such as cancer-associated fibroblasts (CAFs), and transformed carcinoma cells. This very high degree of heterogeneity likely contributes to acquired drug resistance, tumour dormancy, relapse, and distant or lymph node metastasis. ITH, in turn, is likely promoted by pronounced tumour cell plasticity, which manifests in highly dynamic and reversible phenomena such as of partial or hybrid forms of epithelial-to-mesenchymal transition (EMT), and enhanced tumour stemness. Stemness and tumour cell plasticity are strongly promoted by Notch signalling, which remains poorly understood especially in HNSCC. Here, we aim to elucidate how Notch signal may act both as a tumour suppressor and proto-oncogenic, probably during different stages of tumour cell initiation and progression. Notch signalling also interacts with numerous other signalling pathways, that may also have a decisive impact on tumour cell plasticity, acquired radio/chemoresistance, and metastatic progression of HNSCC. We outline the current stage of research related to Notch signalling, and how this pathway may be intricately interconnected with other, druggable targets and signalling mechanisms in HNSCC.

Hey1 promotes migration and invasion of melanoma cells via GRB2/PI3K/AKT signaling cascade

Increasing evidence indicates that Notch signaling regulates multiple intracellular biological processes in malignant melanoma. Whereas how Notch signaling is transduced to influence melanoma cell behaviors remains largely elusive. Here we show that the Notch signaling downstream target Hey1 promotes migration and invasion of melanoma cells via the GRB2/PI3K/AKT pathway. First, bioinformatics tools, immunohistochemistry, and Western blotting analysis showed that the expression of Hey1 is increased in melanoma. Then, both in vivo and in vitro experiments showed that Hey1 promotes the malignant behaviour of the melanoma cells. High-throughput RNA-sequencing analysis revealed that inhibition of Hey1 results in decreased GRB2 expression in melanoma cells. Last, functional experiments confirmed that Hey1 positively regulates GRB2/PI3K/AKT pathway to influence migration and invasion of melanoma cells. In summary, our results suggest that Hey1 promotes the invasion and metastasis of melanoma cells by regulating GRB2/PI3K/AKT pathway. Our study provides potential therapeutics in tumor biology.

ROS-Nrf2 pathway mediates the development of TGF-β1-induced epithelial-mesenchymal transition through the activation of Notch signaling

Epithelial-mesenchymal transition (EMT) is a cellular process by which epithelial cells transform to acquire mesenchymal phenotypes. Accumulating evidence indicate the involvement of EMT in the progression of malignant diseases. Notch signaling mediates TGF-β1-induced EMT through direct transcriptional activation of Snai1. The molecular mechanism how TGF-β1 activates Notch signaling, however, remains unknown. In this study, we show a pivotal role for reactive oxygen species (ROS)-Nrf2 pathway in TGF-β1-induced Notch signaling activation and EMT development. TGF-β1 induces Nrf2 activation through ROS production. Inhibiting Nrf2 activation either by reducing ROS levels by N-acetylcysteine or by knocking down of Nrf2 by small interfering RNA attenuated both Notch signaling activation and EMT development. TGF-β1 induced the transcription of Notch4 via Nrf2-dependent promoter activation. In conclusion, our study indicates the ROS-Nrf2 pathway mediates the development of TGF-β1-induced EMT through the activation of Notch signaling.

Epithelial-to-Mesenchymal Transition-Derived Heterogeneity in Head and Neck Squamous Cell Carcinomas

Simple Summary

Head and neck squamous cell carcinomas (HNSCC) are common malignancies with considerable morbidity and a high death toll worldwide. Resistance towards multi-modal therapy modalities composed of surgery, irradiation, chemo- and immunotherapy represents a major obstacle in the efficient treatment of HNSCC patients. Patients frequently show nodal metastases at the time of diagnosis and endure early relapses, oftentimes in the form of local recurrences. Differentiation programs such as the epithelial-to-mesenchymal transition (EMT) allow individual tumor cells to adopt cellular functions that are central to the development of metastases and treatment resistance. In the present review article, the molecular basis and regulation of EMT and its impact on the progression of HNSCC will be addressed.

Abstract

Head and neck squamous cell carcinomas (HNSCC) are common tumors with a poor overall prognosis. Poor survival is resulting from limited response to multi-modal therapy, high incidence of metastasis, and local recurrence. Treatment includes surgery, radio(chemo)therapy, and targeted therapy specific for EGFR and immune checkpoint inhibition. The understanding of the molecular basis for the poor outcome of HNSCC was improved using multi-OMICs approaches, which revealed a strong degree of inter- and intratumor heterogeneity (ITH) at the level of DNA mutations, transcriptome, and (phospho)proteome. Single-cell RNA-sequencing (scRNA-seq) identified RNA-expression signatures related to cell cycle, cell stress, hypoxia, epithelial differentiation, and a partial epithelial-to-mesenchymal transition (pEMT). The latter signature was correlated to nodal involvement and adverse clinical features. Mechanistically, shifts towards a mesenchymal phenotype equips tumor cells with migratory and invasive capacities and with an enhanced resistance to standard therapy. Hence, gradual variations of EMT as observed in HNSCC represent a potent driver of tumor progression that could open new paths to improve the stratification of patients and to innovate approaches to break therapy resistance. These aspects of molecular heterogeneity will be discussed in the present review.

Targeting Notch to Maximize Chemotherapeutic Benefits: Rationale, Advanced Strategies, and Future Perspectives

Simple Summary

The Notch signaling pathway regulates cell proliferation, apoptosis, stem cell self-renewal, and differentiation in a context-dependent fashion both during embryonic development and in adult tissue homeostasis. Consistent with its pleiotropic physiological role, unproper activation of the signaling promotes or counteracts tumor pathogenesis and therapy response in distinct tissues. In the last twenty years, a wide number of studies have highlighted the anti-cancer potential of Notch-modulating agents as single treatment and in combination with the existent therapies. However, most of these strategies have failed in the clinical exploration due to dose-limiting toxicity and low efficacy, encouraging the development of novel agents and the design of more appropriate combinations between Notch signaling inhibitors and chemotherapeutic drugs with improved safety and effectiveness for distinct types of cancer.

Abstract

Notch signaling guides cell fate decisions by affecting proliferation, apoptosis, stem cell self-renewal, and differentiation depending on cell and tissue context. Given its multifaceted function during tissue development, both overactivation and loss of Notch signaling have been linked to tumorigenesis in ways that are either oncogenic or oncosuppressive, but always context-dependent. Notch signaling is critical for several mechanisms of chemoresistance including cancer stem cell maintenance, epithelial-mesenchymal transition, tumor-stroma interaction, and malignant neovascularization that makes its targeting an appealing strategy against tumor growth and recurrence. During the last decades, numerous Notch-interfering agents have been developed, and the abundant preclinical evidence has been transformed in orphan drug approval for few rare diseases. However, the majority of Notch-dependent malignancies remain untargeted, even if the application of Notch inhibitors alone or in combination with common chemotherapeutic drugs is being evaluated in clinical trials. The modest clinical success of current Notch-targeting strategies is mostly due to their limited efficacy and severe on-target toxicity in Notch-controlled healthy tissues. Here, we review the available preclinical and clinical evidence on combinatorial treatment between different Notch signaling inhibitors and existent chemotherapeutic drugs, providing a comprehensive picture of molecular mechanisms explaining the potential or lacking success of these combinations.

Targeting Notch4 in Cancer: Molecular Mechanisms and Therapeutic Perspectives

The dysregulation of Notch signaling is found in many cancers and is closely related to cancer progression. As an important Notch receptor, abnormal Notch4 expression affects several tumor-cell behaviors, including stemness, the epithelial-mesenchymal transition, radio/chemoresistance and angiogenesis. In order to inhibit the oncogenic effects of Notch4 activation, several methods for targeting Notch4 signaling have been proposed. In this review, we summarize the known molecular mechanisms through which Notch4 affects cancer progression. Finally, we discuss potential Notch4-targeting therapeutic strategies as a reference for future research.

Roles of the Immune/Methylation/Autophagy Landscape on Single-Cell Genotypes and Stroke Risk in Breast Cancer Microenvironment

This study sought to perform integrative analysis of the immune/methylation/autophagy landscape on breast cancer prognosis and single-cell genotypes. Breast Cancer Recurrence Risk Score (BCRRS) and Breast Cancer Prognostic Risk Score (BCPRS) were determined based on 6 prognostic IMAAGs obtained from the TCGA-BRCA cohort. BCRRS and BCPRS, respectively, were used to construct a risk prediction model of overall survival and progression-free survival. Predictive capacity of the model was evaluated using clinical data. Analysis showed that BCRRS is associated with a high risk of stroke. In addition, PPI and drug-ceRNA networks based on differences in BCPRS were constructed. Single cells were genotyped through integrated scRNA-seq of the TNBC samples based on clustering results of BCPRS-related genes. The findings of this study show the potential regulatory effects of IMAAGs on breast cancer tumor microenvironment. High AUCs of 0.856 and 0.842 were obtained for the OS and PFS prognostic models, respectively. scRNA-seq analysis showed high expression levels of adipocytes and adipose tissue macrophages (ATMs) in high BCPRS clusters. Moreover, analysis of ligand-receptor interactions and potential regulatory mechanisms were performed. The LINC00276&MALAT1/miR-206/FZD4-Wnt7b pathway was also identified which may be useful in future research on targets against breast cancer metastasis and recurrence. Neural network-based deep learning models using BCPRS-related genes showed that these genes can be used to map the tumor microenvironment. In summary, analysis of IMAAGs, BCPRS, and BCRRS provides information on the breast cancer microenvironment at both the macro- and microlevels and provides a basis for development of personalized treatment therapy.

Comprehensive molecular profiling of pulmonary pleomorphic carcinoma

Information regarding the molecular features of pulmonary pleomorphic carcinoma (PPC) is insufficient. Here, we performed next-generation sequencing to determine the genomic and transcriptomic profiles of PPC. We sequenced the DNAs and RNAs of 78 specimens from 52 patients with PPC. We analyzed 15 PPC cases to identify intratumoral differences in gene alterations, tumor mutation burden (TMB), RNA expression, and PD-L1 expression between epithelial and sarcomatoid components. The genomic alterations of six cases of primary tumors and corresponding metastatic tumors were analyzed. KRAS mutations (27%) were the most common driver mutations, followed by EGFR (8%), and MET (8%) mutations. Epithelial and sarcomatoid components shared activating driver mutations, and there were no significant differences in CD274 expression or TMB between the two components. However, PD-L1 was highly expressed in the sarcomatoid component of several cases compared with the epithelial component. Primary and metastatic tumors shared oncogenic mutations among genes such as KRAS and TP53, and additional alterations including NOTCH4 mutations were specifically identified in the metastatic regions. Our data suggest that therapies targeting activating driver mutations may be effective for patients with PPC and that immune checkpoint inhibitors of PPC may be recommended after careful assessment of PD-L1 expression in each epithelial and sarcomatoid component.

ECM Remodeling in Squamous Cell Carcinoma of the Aerodigestive Tract: Pathways for Cancer Dissemination and Emerging Biomarkers

Squamous cell carcinomas (SCC) include a number of different types of tumors developing in the skin, in hollow organs, as well as the upper aerodigestive tract (UADT) including the head and neck region and the esophagus which will be dealt with in this review. These tumors are often refractory to current therapeutic approaches with poor patient outcome. The most important prognostic determinant of SCC tumors is the presence of distant metastasis, significantly correlating with low patient survival rates. Rapidly emerging evidence indicate that the extracellular matrix (ECM) composition and remodeling profoundly affect SSC metastatic dissemination. In this review, we will summarize the current knowledge on the role of ECM and its remodeling enzymes in affecting the growth and dissemination of UADT SCC. Taken together, these published evidence suggest that a thorough analysis of the ECM composition in the UADT SCC microenvironment may help disclosing the mechanism of resistance to the treatments and help defining possible targets for clinical intervention.

ECM Remodeling in Squamous Cell Carcinoma of the Aerodigestive Tract: Pathways for Cancer Dissemination and Emerging Biomarkers

Simple Summary

Local and distant metastasis of patients affected by squamous cell carcinoma of the upper aerodigestive tract predicts poor prognosis. In the latest years, the introduction of new therapeutic approaches, including targeted and immune therapies, has improved the overall survival. However, a large number of these patients do not benefit from these treatments. Thus, the identification of suitable prognostic and predictive biomarkers, as well as the discovery of new therapeutic targets have emerged as a crucial clinical need. In this context, the extracellular matrix represents a suitable target for the development of such therapeutic tools. In fact, the extracellular matrix is composed by complex molecules able to interact with a plethora of receptors and growth factors, thus modulating the dynamic crosstalk between cancer cells and the tumor microenvironment. In this review, we summarize the current knowledge of the role of the extracellular matrix in affecting squamous cell carcinoma growth and dissemination. Despite extracellular matrix is known to affect the development of many cancer types, only a restricted number of these molecules have been recognized to impact on squamous cell carcinoma progression. Thus, we consider that a thorough analysis of these molecules may be key to develop new potential therapeutic targets/biomarkers.

Abstract

Squamous cell carcinomas (SCC) include a number of different types of tumors developing in the skin, in hollow organs, as well as the upper aerodigestive tract (UADT) including the head and neck region and the esophagus which will be dealt with in this review. These tumors are often refractory to current therapeutic approaches with poor patient outcome. The most important prognostic determinant of SCC tumors is the presence of distant metastasis, significantly correlating with low patient survival rates. Rapidly emerging evidence indicate that the extracellular matrix (ECM) composition and remodeling profoundly affect SSC metastatic dissemination. In this review, we will summarize the current knowledge on the role of ECM and its remodeling enzymes in affecting the growth and dissemination of UADT SCC. Taken together, these published evidence suggest that a thorough analysis of the ECM composition in the UADT SCC microenvironment may help disclosing the mechanism of resistance to the treatments and help defining possible targets for clinical intervention.

Inhibition of the Notch signaling pathway attenuates progression of cell motility, metastasis, and epithelial-to-mesenchymal transition-like phenomena induced by low concentrations of cisplatin in osteosarcoma

Although advances in osteosarcoma treatment have been made in recent decades, the survival rate for patients suffering from metastatic disease, especially lung metastasis, remains disappointing. Previous studies have confirmed that epithelial-to-mesenchymal transition (EMT) is associated with tumor metastasis, and several studies have suggested that osteosarcoma cells also exhibit EMT-like characteristics. In addition, Notch signaling is known to be related to the development and progression of human malignancies, including osteosarcoma. However, whether chemotherapy affects the EMT-like events and whether these events are medicated by Notch signaling remain to be elucidated. To address these issues, in the current work, osteosarcoma 143B cells were exposed to sublethal concentrations of the first-line chemotherapeutic agent cisplatin (DDP), which promoted cell migration, in vitro invasion, and in vivo lung metastasis. Furthermore, low concentrations of DDP upregulated mesenchymal phenotype-related genes and proteins and promoted EMT-like properties in osteosarcoma cells. In addition, low concentrations of DDP could activate the Notch receptor and its target genes. Finally, combined treatment of DDP with the Notch signaling pathway inhibitor DAPT, which can effectively downregulate mesenchymal phenotype-related genes and proteins, inhibited cell migration and invasion in vitro, and it decreased pulmonary metastatic nodules in vivo. The results of the current study supported the idea that low concentrations of DDP could induce EMT-like characteristics in osteosarcoma cells and could promote cell mobility in vitro, as well as pulmonary metastasis in vivo. Importantly, however, these biological processes are mediated by the Notch signaling pathway. Blocking the Notch signaling pathway can effectively attenuate the osteosarcoma EMT-like phenotype and its associated migration, invasion, and metastasis.

Long noncoding RNA LINC00982 upregulates CTSF expression to inhibit gastric cancer progression via the transcription factor HEY1

Upregulating the expression of long noncoding RNA LINC00982 controlled cell proliferation in gastric cancer, but the regulatory molecular mechanisms are yet to be expounded. We here aimed to elaborate how LINC00982 regulated the malignancy of gastric cancer cells. RT-qPCR and Western blot analysis were used to detect the expression of LINC00982 and cathepsin F (CTSF) in gastric cancer tissues and cells. Modulatory effect of LINC00982 on gastric cancer cells was assessed by CCK-8, colony formation, Transwell migration, and invasion assays. The relationship between LINC00982, YRPW motif 1 (HEY1), and CTSF was examined by RNA-binding protein immunoprecipitation, luciferase assay, and chromatin immunoprecipitation, and their interaction in the regulation of gastric cancer cellular functions was analyzed by performing gain-of-function and rescue assays. The nude mouse model of tumor formation was developed to examine the effects of LINC00982 on tumorigenesis. LINC00982 was lowly expressed in gastric cancer tissues, whereas its overexpression impaired the proliferative, migratory, and invasive properties of gastric cancer cells. Furthermore, LINC00982 could bind to transcription factor HEY1 and inhibited its expression. Through blocking the binding of HEY1 to CTSF promoter, LINC00982 promoted the expression of CTSF. Overexpression of HEY1 or inhibition of CTSF could reverse the antitumor effects of LINC00982 on gastric cancer, which were further demonstrated in vivo. All these taken together, LINC00982 acted as a tumor suppressor in gastric cancer, which is therefore suggested to be a potential antitumor target for gastric cancer.NEW & NOTEWORTHY We identified LINC00982 as a promising antitumor target for the treatment of patients with gastric cancer. We also determined a regulatory network involved in the pathophysiology of gastric cancer wherein LINC00982 could bind to HEY1 to impair its binding to cathepsin F (CTSF) promoter and hence promote CTSF expression, which aids in better understanding of molecular mechanisms related to gastric tumorigenesis.

Inhibition of Notch Intracellular Domain Suppresses Cell Activation and Fibrotic Factors Production in Hypertrophic Scar Fibroblasts Versus Normal Skin Fibroblasts

BACKGROUND

Hypertrophic scar (HS) is the most common complication after skin injury with unknown etiopathogenesis. There is increasing evidence to suggest that aberrant Notch signaling contributes directly to skin pathogenesis and altered expression of the Notch intracellular domain (NICD) identified in HS. Therefore, the aim of this study was to investigate the effects of Notch signaling pathway in HS pathogenesis.

METHODS

Hypertrophic scar and normal skin samples were collected. Notch intracellular domain expression was detected by immunohistochemistry staining and fibroblasts were separated from the samples. We compared fibrotic factors production, cell viability, migration and apoptosis of HS fibroblasts (HFB) versus normal skin fibroblasts (NFB) by real time quantitative polymerase chain reaction, MTS, cell scratch assay and flow cytometry respectively under the impact of inhibition of Notch signaling by NICD-small-interfering RNA (SiRNA).

RESULTS

The results showed that NICD was overexpressed in the dermis of HS tissues. Inhibition of Notch signaling by NICD-SiRNA suppressed the production of the fibrotic factors including collagen 1, collagen 3, α-SMA, and TGF-β1 by HFB and NFB. Cell viability and migration were reduced in NICD-SiRNA-treated NFB and HFB, whereas cell apoptosis was enhanced by NICD-SiRNA.

CONCLUSIONS

Conclusively, the study demonstrates a potential role for Notch signaling in HS progression, and targeting this pathway may provide a novel strategy for treatment of HS.

4sc-202 and Ink-128 cooperate to reverse the epithelial to mesenchymal transition in OSCC

Treatment of oral squamous cell carcinoma remains a challenge due to a high incidence of treatment resistance, which is followed by tumor recrudescence and metastasis to the lymph nodes. Thus, it is important to explore novel inhibitors of OSCC. Here, we aimed to identify drugs that may cooperate with histone deacetylase inhibitors to reverse the EMT, inhibit EMT and cell migration and invasion, and contribute to therapeutic efficacy. We found that treatment with 4sc-202 potently reversed the EMT and thereby inhibited cell migration and invasion in vitro, in part by inducing expression of the FoxO1 tumor-suppressor gene. Furthermore, 4sc-202 also synergized with Ink-128 to inhibit tumor migration and invasion in vitro. Mechanistically, 4sc-202 induced FoxO1 expression, whereas Ink-128 promoted nuclear translocation of FoxO1. Our findings indicated that FoxO1 might reverse the EMT by interacting with Twist1 in OSCC. In conclusion, we identified an effective combination therapy involving class I histone deacetylase and mammalian target of rapamycin complex 1/2 inhibition that effectively blocked the EMT of tumor cells by upregulating FoxO1 expression to inhibit Twist1 transcription. These data have implications for developing new targets for early diagnosis and treatment of OSCC.

Potential Role of Musashi-2 RNA-Binding Protein in Cancer EMT

Local invasion and distant metastasis are the key hallmarks in the aggressive progression of malignant tumors, including the ability of cancer cells to detach from the extracellular matrix overcome apoptosis, and disseminate into distant sites. It is generally believed that this malignant behavior is stimulated by epithelial-mesenchymal transition (EMT). Musashi (MSI) RNA-binding proteins, belonging to the evolutionarily conserved RNA-binding proteins (RBP) family, were originally discovered to regulate asymmetric cell division during embryonic development. Recently, Musashi-2 (MSI2), as a key member of MSI family, has been prevalently reported to be tightly associated with the advanced clinical stage of several cancers. Multiple oncogenic signaling pathways mediated by MSI2 play vital roles in EMT. Here, we systematically reviewed the detailed role and signal networks of MSI2 in regulating cancer development, especially in EMT signal transduction, involving EGF, TGF-β, Notch, and Wnt pathways.

A Survival-Related Competitive Endogenous RNA Network of Prognostic lncRNAs, miRNAs, and mRNAs in Wilms Tumor

Wilms tumor (WT) commonly occurs in infants and children. We evaluated clinical factors and the expression of multiple RNAs in WT samples in the TARGET database. Eight long non-coding RNAs (lncRNAs; AC079310.1, MYCNOS, LINC00271, AL445228.3, Z84485.1, AC091180.5, AP002518.2, and AC007879.3), two microRNAs (miRNAs; hsa-mir-152 andhsa-mir-181a), and nine messenger RNAs (mRNAs; TCTEX1D4, RNF133, VRK1, CCNE1, HEY1, C10orf71, SPRY1, SPAG11A, and MAGEB18) were screened from differentially expressed RNAs and used to construct predictive survival models. These models showed good prognostic ability and were highly correlated with tumor stage and histological classification. Additionally, survival-related ceRNA network was constructed using 35 RNAs (15 lncRNAs, eight miRNAs, and 12 mRNAs). KEGG pathway analysis suggested the "Wnt signaling pathway" and "Cellular senescence" as the main pathways. In conclusion, we established a multinomial predictive survival model and a survival-related ceRNA network, which provide new potential biomarkers that may improve the prognosis and treatment of WT patients.

Notch Signaling and Human Papillomavirus-Associated Oral Tumorigenesis

The NOTCH pathway is critical for the development of many cell types including the squamous epithelium lining of cutaneous and mucosal surfaces. In genetically engineered mouse models, Notch1 acts as one of the first steps to commit basal keratinocytes to terminally differentiate. Similarly, in human head and neck squamous cell cancers (HNSCCs), NOTCH1 is often lost consistent with its essential tumor-suppressive role for initiating keratinocyte differentiation. However, constitutive NOTCH1 activity in the epithelium results in expansion of the spinous keratinocyte layers and impaired terminal differentiation is consistent with the role of NOTCH1 as an oncogene in other cancers, especially in T-cell acute lymphoblastic leukemia. We have previously observed that NOTCH1 plays a dual role as both a tumor suppressor and oncogene, depending on the mutational context of the tumor. Namely, gain or loss or NOTCH1 activity promotes the development of human papillomavirus (HPV)-associated cancers. The additional HPV oncogenes likely disrupt the tumor-suppressive activities of NOTCH and enable the oncogenic pathways activated by NOTCH to promote tumor growth. In this review, we detail the role of NOTCH pathway in head and neck cancers with a focus on HPV-associated cancers.

NOTCH and Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is a deadly disease that requires extensive research on its mechanisms, prevention, and therapy. Recent studies have shown that NOTCH mutations are commonly seen in human ESCC. This chapter summarizes our current understanding of the NOTCH pathway in normal esophagus and in ESCC. In normal esophagus, NOTCH pathway regulates the development of esophageal squamous epithelium, in particular, squamous differentiation. Exposure to extrinsic and intrinsic factors, such as gastroesophageal reflux, alcohol drinking, and inflammation, downregulates the NOTCH pathway and thus inhibits squamous differentiation of esophageal squamous epithelial cells. In ESCC, NOTCH plays a dual role as both a tumor suppressor pathway and an oncogenic pathway. In summary, further studies are warranted to develop NOTCH activators for the prevention of ESCC and NOTCH inhibitors for targeted therapy of a subset of ESCC with activated NOTCH pathway.

High expression of Notch2 drives tongue squamous cell carcinoma carcinogenesis

Tongue squamous cell carcinoma (TSCC) is one of the most common cancers in the oral cavity. Notch signaling is frequently dysregulated in cancer. However, the role of Notch2 in TSCC is not well understood. The aim of this study was to investigate the effect of abnormal expression of Notch2 in TSCC. The expression of Notch2 was tested in 47 pairs of tissues from tongue cancer and normal samples by using immunohistochemical staining. Tongue cancer cells were transfected with siRNA or plasmid. The proliferation of the cells was tested by the CCK8 assay and colony formation assay. Subcutaneous tumor model was established to observe tumor growth. Transwell assay was used to detect the changes of cell migration and invasion ability. A humanized anti-Notch2 antibody was used to TSCC cells. We found that Notch2 was upregulated in tongue carcinoma tissues. Knocking down the expression of Notch2 by siRNA in the TSCC cell lines decreased proliferation ability both in vitro and in vivo. In addition, migration and invasion abilities were inhibited by knockdown of Notch2 in the TSCC cells. However, overexpression of Notch2 increased tongue cancer cell proliferation, invasion and migration. The humanized anti-Notch2 antibody inhibited TSCC cell growth. The results indicated that Notch2 is an oncogene in tongue squamous cell carcinoma and may become the target of a new approach for treating TSCC.

Reciprocal activation of HEY1 and NOTCH4 under SOX2 control promotes EMT in head and neck squamous cell carcinoma

Several comprehensive studies have demonstrated that the NOTCH pathway is altered in a bimodal manner in head and neck squamous cell carcinoma (HNSCC). In a previous study, it was found that the NOTCH4/HEY1 pathway was specifically upregulated in HNSCC and promoted epithelial-mesenchymal transition (EMT), and that HEY1 activation supported SOX2 expression. However, the interactions in this pathway have not yet been fully elucidated. The present study investigated the NOTCH4/HEY1/SOX2 axis in HNSCC using in vitro models and the Cancer Genome Atlas (TCGA) database. To explore the association, reporter and ChIP RT-qPCR assays using SOX2-overexpressing (SOX2-OE) cells were performed. The association between NOTCH4 and HEY1 was examined in the same manner using HEY1-overexpressing (HEY1-OE) cells. The results of the in vitro experiments indicated that HEY1 promoted EMT in the HNSCC cells. Furthermore, the overexpression of HEY1 also promoted sphere formation and increased murine xenograft tumorigenicity. Reporter assays and ChIP RT-qPCR experiments indicated that SOX2 regulated HEY1 expression via direct binding of the HEY1 promoter. HEY1 expression significantly correlated with SOX2 expression in primary lung SCC and other SCCs using the TCGA database. HEY1 also regulated NOTCH4 expression to create a positive reciprocal feedback loop. On the whole, the present study demonstrates that HEY1 expression in HNSCC is regulated via the promotion of SOX2 and promotes EMT. The NOTCH4/HEY1 pathway is specifically upregulated via a positive reciprocal feedback loop mediated by the HEY1-medaited regulation of NOTCH4 transcription, and SOX2 correlates with HEY1 expression in SCC from other primary sites.

miR-223 regulates oral squamous cell carcinoma metastasis through the Wnt/β-catenin signaling pathway

OBJECTIVES

Metastasis seriously affects the prognosis of patients with oral squamous cell carcinoma (OSCC); however, the precise mechanism remains poorly understood.

MATERIALS AND METHODS

microRNA (miRNA) array analysis of four cell lines was used to identify candidate miRNAs. The Cancer Genome Atlas (TCGA) database was used to verify the relationship between candidate miRNAs and OSCC metastasis. Transwell chambers and mouse model experiments were used to analyze OSCC cell migration and invasion abilities in vitro and in vivo. Additionally, bioinformatics and a dual luciferase reporter assay were used to identify selected miRNA target genes. A multicenter clinical cohort of 250 patients with OSCC was set up to evaluate the diagnostic and predicted value of the target genes. Finally, the molecular mechanism of a selected miRNA regulating OSCC metastasis was further explored.

RESULTS

miR-223 expression was found to be negatively correlated with OSCC cell invasion and migration abilities. TCGA database data confirmed the relationship between miR-223 expression and OSCC metastasis. Functional experiments indicated that overexpression of miR-223 could decrease the metastasis ability of OSCC cells, while decreasing its expression level led to the enhancement of OSCC metastasis. Bioinformatics and a dual-luciferase reporter assay identified that miR-223 directly targets transcription factor 7-like 2 (TCF7L2). Additionally, TCF7L2 was shown to be negatively correlated with patient metastasis and survival.

CONCLUSIONS

miR-223 regulates OSCC invasion and metastasis by directly targeting TCF7L2 and potentiating the Wnt/β-catenin signaling pathway. These findings demonstrate the versatile role of miR-223 in carcinogenesis. miR-223 might serve as an attractive OSCC metastasis intervention target.

Cancer Stem Cells, Quo Vadis? The Notch Signaling Pathway in Tumor Initiation and Progression

The Notch signaling pathway regulates cell proliferation, cytodifferentiation and cell fate decisions in both embryonic and adult life. Several aspects of stem cell maintenance are dependent from the functionality and fine tuning of the Notch pathway. In cancer, Notch is specifically involved in preserving self-renewal and amplification of cancer stem cells, supporting the formation, spread and recurrence of the tumor. As the function of Notch signaling is context dependent, we here provide an overview of its activity in a variety of tumors, focusing mostly on its role in the maintenance of the undifferentiated subset of cancer cells. Finally, we analyze the potential of molecules of the Notch pathway as diagnostic and therapeutic tools against the various cancers.

TWIST1 correlates with Notch signaling pathway to develop esophageal squamous cell carcinoma

Notch signaling pathway mediates different biological processes including stem cell self-renewal, progenitor cell fate decision, and terminal differentiation. TWIST1 plays a key role in tumor development and metastasis through inducing epithelial-mesenchymal transition (EMT). Expression of the core transcriptional complex of Notch pathway and its target genes, as well as TWIST1 overexpression, are closely related to the aggressive clinicopathological variables of esophageal squamous cell carcinoma (ESCC). Here we aimed to functionally elucidate probable crosstalk between TWIST1 and Notch pathway in ESCCs. Correlation between TWIST1 and Notch target genes was analyzed in 50 ESCCs and corresponding normal tissues. Using retroviral system, enforced expression of TWIST1 was established in ESCC line KYSE-30 cells and expression of Notch signaling genes was assessed. Significant correlation between TWIST1 and HEY1/HEY2 expression was found in different pathological variable of ESCC poor prognosis. Induced expression of TWIST1 in KYSE-30 cells caused a noteworthy increase of Notch pathway genes expression revealing regulatory role of TWIST1 on Notch signaling genes in the cells. Based on existed correlations between expression of TWIST1 and Notch pathway genes in different pathological features of ESCC patients, as well as KYSE-30 cell line, we may extrapolate that TWIST1 is involved in aggressiveness of the disease through regulation of Notch signaling genes. To the best of knowledge, this is the first report describing the impact of TWIST1 on Notch cascade genes in ESCC.

The role of microRNA in cisplatin resistance or sensitivity

INTRODUCTION

Cisplatin is a chemotherapy drug that has been used to treat a number of cancers for decades, and is still one of the most commonly used anti-cancer agents. However, some patients do not respond to cisplatin while other patients who were originally sensitive to cisplatin eventually develop chemoresistance, leading to treatment failure or/and tumor recurrence.

AREAS COVERED

Different mechanisms contribute to cisplatin resistance or sensitivity, involving multiple pathways or/and processes such as DNA repair, DNA damage response, drug transport, and apoptosis. Among the various mechanisms, it appears that microRNAs play an important role in determining the resistance or sensitivity. In this article, we analyzed and summarized recent findings in this area, with the aim that these data can aid further research and understanding, leading to the eventual reduction of cisplatin resistance.

EXPERT COMMENTARY

microRNAs can positively or negatively regulate cisplatin resistance by acting on molecules or/and pathways related to apoptosis, autophagy, hypoxia, cancer stem cells, NF-κB, and Notch1. It appears that the modulation of relevant microRNAs can effectively re-sensitize cancer cells to cisplatin regimen in certain types of cancers including breast, colorectal, gastric, liver, lung, ovarian, prostate, testicular, and thyroid cancers.

Expression of let-7i and miR-192 is associated with resistance to cisplatin-based chemoradiotherapy in patients with larynx and hypopharynx cancer

OBJECTIVES

The majority of patients with locally advanced larynx or hypopharynx squamous cell carcinoma are treated with organ-preserving chemoradiotherapy (CRT). Clinical outcome following CRT varies greatly. We hypothesized that tumor microRNA (miRNA) expression is predictive for outcome following CRT.

METHODS

Next-generation sequencing (NGS) miRNA profiling was performed on 37 formalin-fixed paraffin-embedded (FFPE) tumor samples. Patients with a recurrence-free survival (RFS) of less than 2 years and patients with late/no recurrence within 2 years were compared by differential expression analysis. Tumor-specific miRNAs were selected based on normal mucosa miRNA expression data from The Cancer Genome Atlas database. A model was constructed to predict outcome using group-regularized penalized logistic ridge regression. Candidate miRNAs were validated by RT-qPCR in the initial sample set as well as in 46 additional samples.

RESULTS

Thirteen miRNAs were differentially expressed (p < 0.05, FDR < 0.1) according to outcome group. Initial class prediction in the NGS cohort (n = 37) resulted in a model combining five miRNAs and disease stage, able to predict CRT outcome with an area under the curve (AUC) of 0.82. In the RT-qPCR cohort (n = 83), 25 patients (30%) experienced early recurrence (median RFS 8 months; median follow-up 42 months). Class prediction resulted in a model combining let-7i-5p, miR-192-5p and disease stage, able to discriminate patients with good versus poor clinical outcome (AUC:0.80).

CONCLUSION

The combined miRNA expression and disease stage prediction model for CRT outcome is superior to using either factor alone. This study indicates NGS miRNA profiling using FFPE specimens is feasible, resulting in clinically relevant biomarkers.

IMPAD1 functions as mitochondrial electron transport inhibitor that prevents ROS production and promotes lung cancer metastasis through the AMPK-Notch1-HEY1 pathway

The tumor microenvironment (TME) and metabolic reprogramming have been implicated in cancer development and progression. However, the link between TME, metabolism, and cancer progression in lung cancer is unclear. In the present study, we identified IMPAD1 from the conditioned medium of highly invasive CL1-5. High expression of IMPAD1 was associated with a poorer clinical phenotype in lung cancer patients, with reduced survival and increased lymph node metastasis. Knockdown of IMPAD1 significantly inhibited migration/invasion abilities and metastasis in vitro and in vivo. Upregulation of IMPAD1 and subsequent accumulation of AMP in cells increased the pAMPK, leading to Notch1 and HEY1 upregulation. As AMP is an ADORA1 agonist, treatment with ADORA1 inhibitor reduced the expression of pAMPK and HEY1 expression in IMPAD1-overexpressing cells. IMPAD1 caused mitochondria dysfunction by inhibiting mitochondrial Complex I activity, which reduced mitochondrial ROS levels and activated the AMPK-HEY1 pathway. Collectively this study supports the multipotent role of IMPAD1 in promotion of lung cancer metastasis by simultaneously increasing AMP levels, inhibition of Complex I activity to decrease ROS levels, thereby activating AMPK-Notch1-HEY1 signaling, and providing an alternative metabolic pathway in energy stress conditions.

Crosstalk between MEIS1 and markers of different cell signaling pathways in esophageal squamous cell carcinoma

The homeobox transcription factor MEIS1 is involved in cell fate decision, stem cells properties, gastrointestinal (GI) tract development, and progression of several malignancies such as esophageal squamous cell carcinoma (ESCC). Increasing evidences suggest the crosstalk between MEIS1 and cell signaling pathways. Therefore, our aim in present study was to investigate the probable linkage of MEIS1 expression with key genes of different cell signaling pathways in ESCC tumorigenesis, and their correlation with clinicopathological feature of the patients. The gene expression profiling of MEIS1 and different cell signaling genes including SALL4, SIZN1, and HEY1 (stemness state, BMP, and NOTCH signaling pathways, respectively) was performed using quantitative real-time reverse transcription polymerase chain reaction (PCR) in fresh tumoral compared to margin normal tissues of 50 treatment-naive ESCC samples. The mRNA expression of MEIS1/SIZN1, SIZN1/HEY1, and SIZN1/SALL4 were significantly associated to each other (P < 0.05). There were remarkable correlations between concomitant mRNA expression of MEIS1 and SIZN1 in tumors with invasion to adventitia, early stages of tumor progression and poorly differentiated tumors. Moreover, expression of MEIS1 and HEY1 was correlated to each other in primary stages of tumor progression and non-invaded tumors. Expression of MEIS1 was significantly associated with SALL4 in poorly differentiated tumors. Our results indicated that correlation between different cell signaling pathway-related genes may lead to esophageal tumorigenesis. It is illustrated that MEIS1 as a HOX gene has a significant correlation with stemness state, BMP, and NOTCH signaling pathways via the SIZN1.

The NOTCH1-HEY1 pathway regulates self-renewal and epithelial-mesenchymal transition of salivary adenoid cystic carcinoma cells

Our previous study demonstrated a close relationship between the NOTCH signaling pathway and salivary adenoid cystic carcinoma (SACC). Its receptor gene, NOTCH1, and its downstream gene, HES1, contribute to the proliferation, invasion and metastasis of SACC. Accumulating evidence supports HEY1 as another effector of the signaling pathway. The purpose of this study was to explore the effects of the NOTCH1-HEY1 pathway on the proliferation, invasion and metastasis of SACC cells. Our results verified that HEY1 is a specific molecular target of the NOTCH signaling pathway in SACC cells and that its expression in carcinoma is much higher than that in paracarcinoma tissues. The expression of NOTCH1 and HEY1 are positively correlated in the salivary adenoid cystic carcinoma tissues. NOTCH1 is significantly related to the activation of HEY1 in SACC, and that HEY1 reciprocally regulates NOTCH1 expression in SACC. HEY1 promotes cell proliferation and spheroid formation and inhibits cell apoptosis in vitro. In addition, HEY1 enhances the tumorigenicity of SACC in vivo. Furthermore, HEY1 increases cell invasion and metastasis by driving the expression of epithelial-mesenchymal transition (EMT)-related genes and MMPs. The results of this study indicate that the NOTCH1-HEY1 pathway is specifically upregulated in SACC and promotes cell proliferation, self-renewal, invasion, metastasis and the expression of EMT-related genes and MMPs. Our findings suggest that a NOTCH1-HEY1 pathway inhibitor might therefore have potential therapeutic applications in treating SACC patients by inhibiting cancer cell growth and metastasis.

New insights into the mechanisms of epithelial-mesenchymal transition and implications for cancer

Epithelial-mesenchymal transition (EMT) is a cellular programme that is known to be crucial for embryogenesis, wound healing and malignant progression. During EMT, cell-cell and cell-extracellular matrix interactions are remodelled, which leads to the detachment of epithelial cells from each other and the underlying basement membrane, and a new transcriptional programme is activated to promote the mesenchymal fate. In the context of neoplasias, EMT confers on cancer cells increased tumour-initiating and metastatic potential and a greater resistance to elimination by several therapeutic regimens. In this Review, we discuss recent findings on the mechanisms and roles of EMT in normal and neoplastic tissues, and the cell-intrinsic signals that sustain expression of this programme. We also highlight how EMT gives rise to a variety of intermediate cell states between the epithelial and the mesenchymal state, which could function as cancer stem cells. In addition, we describe the contributions of the tumour microenvironment in inducing EMT and the effects of EMT on the immunobiology of carcinomas.

Notch Signaling Molecules as Prognostic Biomarkers for Acute Myeloid Leukemia

The role of Notch signaling in acute myeloid leukemia (AML) is still under investigation. We have previously shown that high levels of Notch receptors and ligands could interfere with drug response. In this study, the protein expression of 79 AML blast samples collected from newly diagnosed patients was examined through flow cytometry. Gamma-secretase inhibitors were used in AML mouse xenograft models to evaluate the contribution of Notch pharmacological inhibition to mouse survival. We used univariate analysis for testing the correlation and/or association between protein expression and well-known prognostics markers. All the four receptors (Notch1-4) and some ligands (Jagged2, DLL-3) were highly expressed in less mature subtypes (M0-M1). Notch3, Notch4, and Jagged2 were overexpressed in an adverse cytogenetic risk group compared to good cytogenetic risk patients. Chi-square analysis revealed a positive association between the complete remission rate after induction therapy and weak expression of Notch2 and Notch3. We also found an association between low levels of Notch4 and Jagged2 and three-year remission following allogeneic stem cell transplantation (HSCT). Accordingly, Kaplan-Meier analysis showed improved OS for patients lacking significant expression of Notch4, Jagged2, and DLL3. In vivo experiments in an AML mouse model highlighted both improved survival and a significant reduction of leukemia cell burden in the bone marrow of mice treated with the combination of Notch pan-inhibitors (GSIs) plus chemotherapy (Ara-C). Our results suggest that Notch can be useful as a prognostic marker and therapeutic target in AML.