Loss of Notch1 predisposes oro-esophageal epithelium to tumorigenesis

Jag1/2 maintain esophageal homeostasis and suppress foregut tumorigenesis by restricting the basal progenitor cell pool

Basal progenitor cells are crucial for maintaining foregut (the esophagus and forestomach) homeostasis. When their function is dysregulated, it can promote inflammation and tumorigenesis. However, the mechanisms underlying these processes remain largely unclear. Here, we employ genetic mouse models to reveal that Jag1/2 regulate esophageal homeostasis and foregut tumorigenesis by modulating the function of basal progenitor cells. Deletion of Jag1/2 in mice disrupts esophageal and forestomach epithelial homeostasis. Mechanistically, Jag1/2 deficiency impairs activation of Notch signaling, leading to reduced squamous epithelial differentiation and expansion of basal progenitor cells. Moreover, Jag1/2 deficiency exacerbates the deoxycholic acid (DCA)-induced squamous epithelial injury and accelerates the initiation of squamous cell carcinoma (SCC) in the forestomach. Importantly, expression levels of JAG1/2 are lower in the early stages of human esophageal squamous cell carcinoma (ESCC) carcinogenesis. Collectively, our study demonstrates that Jag1/2 are important for maintaining esophageal and forestomach homeostasis and the onset of foregut SCC.

Reconstruction of the regulatory hypermethylation network controlling hepatocellular carcinoma development during hepatitis C viral infection

Hepatocellular carcinoma (HCC) has been associated with hepatitis C viral (HCV) infection as a potential risk factor. Nonetheless, the precise genetic regulatory mechanisms triggered by the virus, leading to virus-induced hepatocarcinogenesis, remain unclear. We hypothesized that HCV proteins might modulate the activity of aberrantly methylated HCC genes through regulatory pathways. Virus-host regulatory pathways, interactions between proteins, gene expression, transport, and stability regulation, were reconstructed using the ANDSystem. Gene expression regulation was statistically significant. Gene network analysis identified four out of 70 HCC marker genes whose expression regulation by viral proteins may be associated with HCC: DNA-binding protein inhibitor ID - 1 (ID1), flap endonuclease 1 (FEN1), cyclin-dependent kinase inhibitor 2A (CDKN2A), and telomerase reverse transcriptase (TERT). It suggested the following viral protein effects in HCV/human protein heterocomplexes: HCV NS3(p70) protein activates human STAT3 and NOTC1; NS2-3(p23), NS5B(p68), NS1(E2), and core(p21) activate SETD2; NS5A inhibits SMYD3; and NS3 inhibits CCN2. Interestingly, NS3 and E1(gp32) activate c-Jun when it positively regulates CDKN2A and inhibit it when it represses TERT. The discovered regulatory mechanisms might be key areas of focus for creating medications and preventative therapies to decrease the likelihood of HCC development during HCV infection.

Exploring cell competition for the prevention and therapy of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is characterized by the development of cancer in the esophageal squamous epithelium through a step-by-step accumulation of genetic, epigenetic, and histopathological alterations. Recent studies have demonstrated that cancer-associated gene mutations exist in histologically normal or precancerous clones of the human esophageal epithelium. However, only a small proportion of such mutant clones will develop ESCC, and most ESCC patients develop only one cancer. This suggests that most of these mutant clones are kept in a histologically normal state by neighboring cells with higher competitive fitness. When some of the mutant cells evade cell competition, they become "super-competitors" and develop into clinical cancer. It is known that human ESCC is composed of a heterogeneous population of cancer cells that interact with and influence their environment and neighbors. During cancer therapy, these cancer cells not only respond to therapeutic agents but also compete with each other. Therefore, competition between ESCC cells within the same ESCC tumor is a constantly dynamic process. However, it remains challenging to fine-tune the competitive fitness of various clones for therapeutic benefits. In this review, we will explore the role of cell competition in carcinogenesis, cancer prevention, and therapy, using NRF2, NOTCH pathway, and TP53 as examples. We believe that cell competition is a research area with promising targets for clinical translation. Manipulating cell competition may help improve the prevention and therapy of ESCC.

Notch1 mutations drive clonal expansion in normal esophageal epithelium but impair tumor growth

NOTCH1 mutant clones occupy the majority of normal human esophagus by middle age but are comparatively rare in esophageal cancers, suggesting NOTCH1 mutations drive clonal expansion but impede carcinogenesis. Here we test this hypothesis. Sequencing NOTCH1 mutant clones in aging human esophagus reveals frequent biallelic mutations that block NOTCH1 signaling. In mouse esophagus, heterozygous Notch1 mutation confers a competitive advantage over wild-type cells, an effect enhanced by loss of the second allele. Widespread Notch1 loss alters transcription but has minimal effects on the epithelial structure and cell dynamics. In a carcinogenesis model, Notch1 mutations were less prevalent in tumors than normal epithelium. Deletion of Notch1 reduced tumor growth, an effect recapitulated by anti-NOTCH1 antibody treatment. Notch1 null tumors showed reduced proliferation. We conclude that Notch1 mutations in normal epithelium are beneficial as wild-type Notch1 favors tumor expansion. NOTCH1 blockade may have therapeutic potential in preventing esophageal squamous cancer.

EGFL7 affects the migration of epidermal stem cells in refractory diabetic wounds by regulating Notch signaling pathway

Aim: This study aimed to explore the role of EGFL7 in the healing process of refractory diabetic wounds. Methods: Epidermal stem cells (ESCs) were isolated from healthy mice and diabetic mice, identified by immunofluorescence, transfected with EGFL7 overexpression and silencing lentiviral vectors, and treated with Notch pathway inhibitor (DAPT). Results: SiEGFL7 significantly inhibited the proliferation, invasion and migration of ESCs of healthy mice. DAPT prominently inhibited the expressions of Notch1, Notch2, Hes1 and Jag1 in ESCs of healthy mice induced by overexpressed EGFL7. Overexpressed EGFL7 promoted wound healing in diabetic mice with refractory wounds. Conclusion: EGFL7 affects the proliferation and migration of ESCs in refractory diabetic wounds by regulating the Notch signaling pathway.

Characteristics and response to next-generation sequencing-guided therapy in locally advanced or metastatic esophageal cancer

Esophageal cancer (EC) is a main cause of cancer-related deaths. However, genomic alterations and the clinical value of next-generation sequencing (NGS) in advanced or metastatic EC for precision therapy remain largely unclear. Herein, we performed comprehensive analyses on a cohort of 47 individuals with advanced or metastatic EC who underwent NGS between May 2017 and February 2020. Eventually, 227 mutated genes were identified in the cohort. TP53, NQO1, DPYD, GSTM1, XRCC1 and ERCC1 were the most mutated genes and associated with immune cell infiltration, autophagy and hypoxia. Patients who received NGS-guided treatments exhibited better objective remission rate (ORR) (72.22%), disease control rate (DCR) (88.89%), overall survival (OS) (P = .0019) and progression-free survival (PFS) (P = .0077) than those not receiving NGS-guided therapies. The multivariate analyses further demonstrated that the NGS-guided therapy was an independently prognostic factor (OS: hazard radio [HR] 0.31, 95% coincidence interval [CI] 0.1-0.97, P = .04). In conclusion, we depicted a comprehensive mutational landscape of 47 patients with locally advanced or metastatic EC and illustrated the utility of NGS testing to guide clinical management in improving ORR, DCR, OS and PFS.

Computer analysis of regulation of hepatocarcinoma marker genes hypermethylated by HCV proteins

Hepatitis C virus (HCV) is a risk factor that leads to hepatocellular carcinoma (HCC) development. Epigenetic changes are known to play an important role in the molecular genetic mechanisms of virus-induced oncogenesis. Aberrant DNA methylation is a mediator of epigenetic changes that are closely associated with the HCC pathogenesis and considered a biomarker for its early diagnosis. The ANDSystem software package was used to reconstruct and evaluate the statistical significance of the pathways HCV could potentially use to regulate 32 hypermethylated genes in HCC, including both oncosuppressor and protumorigenic ones identified by genome-wide analysis of DNA methylation. The reconstructed pathways included those affecting protein-protein interactions (PPI), gene expression, protein activity, stability, and transport regulations, the expression regulation pathways being statistically significant. It has been shown that 8 out of 10 HCV proteins were involved in these pathways, the HCV NS3 protein being implicated in the largest number of regulatory pathways. NS3 was associated with the regulation of 5 tumor-suppressor genes, which may be the evidence of its central role in HCC pathogenesis. Analysis of the reconstructed pathways has demonstrated that following the transcription factor inhibition caused by binding to viral proteins, the expression of a number of oncosuppressors (WT1, MGMT, SOCS1, P53) was suppressed, while the expression of others (RASF1, RUNX3, WIF1, DAPK1) was activated. Thus, the performed gene-network reconstruction has shown that HCV proteins can influence not only the methylation status of oncosuppressor genes, but also their transcriptional regulation. The results obtained can be used in the search for pharmacological targets to develop new drugs against HCV-induced HCC.

Telomerase reverse transcriptase promotes angiogenesis in neonatal rats after hypoxic-ischemic brain damage

Background

Angiogenesis is an endogenous repair mechanism following hypoxic-ischemic brain damage (HIBD). Interestingly, recent studies have shown that angiogenesis can be regulated by telomerase reverse transcriptase (TERT), a critical component of telomerase. As telomerase reverse transcriptase can promote angiogenesis after stroke, we hypothesized that it could also promote angiogenesis after HIBD. To test this hypothesis, we developed in vivo and in vitro HIBD models in neonatal rats.

Methods

TERT was overexpressed by lentivirus and adenovirus infection, and levels were measured using quantitative real-time polymerase chain reaction. We used a cell counting kit to quantify the proliferation rate of brain microvascular endothelial cells (BMECs), and immunofluorescence staining to measure CD34 expression levels. A microvessel formation assay was used to evaluate angiogenesis. Blood-brain barrier (BBB) integrity was assessed using immunohistochemical staining for ZO-1 and Evans Blue staining. Lastly, the expression level of Notch-1 was measured by western blotting.

Results

Overexpression of TERT promoted the proliferation of BMECs after hypoxic-ischemic damage in vitro. TERT overexpression increased the formation of microvessels in the neonatal brain after HIBD both in vivo and in vitro. Overexpression of TERT improved BBB integrity in the brains of neonatal rats after HIBD. In addition, the expression level of Notch-1 was increased in BMECs following oxygen glucose deprivation, and overexpression of TERT further increased Notch-1 expression levels in BMECs following oxygen glucose deprivation.

Discussion

Our results reveal that telomerase reverse transcriptase promotes angiogenesis and maintains the integrity of the blood-brain barrier after neonatal hypoxic-ischemic brain damage. Furthermore, the Notch-1 signaling pathway appears to contribute to the angiogenic function of telomerase reverse transcriptase. This protective effect of telomerase reverse transcriptase opens new horizons for future investigations aimed at uncovering the full potential of telomerase reverse transcriptase as a promising new target for the treatment of hypoxic-ischemic encephalopathy.

Targeting the Cbl-b-Notch1 axis as a novel immunotherapeutic strategy to boost CD8+ T-cell responses

A critical feature of cancer is the ability to induce immunosuppression and evade immune responses. Tumor-induced immunosuppression diminishes the effectiveness of endogenous immune responses and decreases the efficacy of cancer immunotherapy. In this study, we describe a new immunosuppressive pathway in which adenosine promotes Casitas B-lineage lymphoma b (Cbl-b)-mediated Notch1 degradation, causing suppression of CD8+ T-cells effector functions. Genetic knockout and pharmacological inhibition of Cbl-b prevents Notch1 degradation in response to adenosine and reactivates its signaling. Reactivation of Notch1 results in enhanced CD8+ T-cell effector functions, anti-cancer response and resistance to immunosuppression. Our work provides evidence that targeting the Cbl-b-Notch1 axis is a novel promising strategy for cancer immunotherapy.

Comparative genomic analysis of esophageal squamous cell carcinoma and adenocarcinoma: New opportunities towards molecularly targeted therapy

Esophageal cancer is one of the most lethal cancers worldwide because of its rapid progression and poor prognosis. Esophageal squamous cell carcinoma (ESCC) and esophageal adenocarcinoma (EAC) are two major subtypes of esophageal cancer. ESCC predominantly affects African and Asian populations, which is closely related to chronic smoking and alcohol consumption. EAC typically arises in Barrett's esophagus with a predilection for Western countries. While surgical operation and chemoradiotherapy have been applied to combat this deadly cancer, molecularly targeted therapy is still at the early stages. With the development of large-scale next-generation sequencing, various genomic alterations in ESCC and EAC have been revealed and their potential roles in the initiation and progression of esophageal cancer have been studied. Potential therapeutic targets have been identified and novel approaches have been developed to combat esophageal cancer. In this review, we comprehensively analyze the genomic alterations in EAC and ESCC and summarize the potential role of the genetic alterations in the development of esophageal cancer. Progresses in the therapeutics based on the different tissue types and molecular signatures have also been reviewed and discussed.

Context Matters: NOTCH Signatures and Pathway in Cancer Progression and Metastasis

The Notch signaling pathway is a critical player in embryogenesis but also plays various roles in tumorigenesis, with both tumor suppressor and oncogenic activities. Mutations, deletions, amplifications, or over-expression of Notch receptors, ligands, and a growing list of downstream Notch-activated genes have by now been described for most human cancer types. Yet, it often remains unclear what may be the functional impact of these changes for tumor biology, initiation, and progression, for cancer therapy, and for personalized medicine. Emerging data indicate that Notch signaling can also contribute to increased aggressive properties such as invasion, tumor heterogeneity, angiogenesis, or tumor cell dormancy within solid cancer tissues; especially in epithelial cancers, which are in the center of this review. Notch further supports the “stemness” of cancer cells and helps define the stem cell niche for their long-term survival, by integrating the interaction between cancer cells and the cells of the tumor microenvironment (TME). The complexity of Notch crosstalk with other signaling pathways and its roles in cell fate and trans-differentiation processes such as epithelial-to-mesenchymal transition (EMT) point to this pathway as a decisive player that may tip the balance between tumor suppression and promotion, differentiation and invasion. Here we not only review the literature, but also explore genomic databases with a specific focus on Notch signatures, and how they relate to different stages in tumor development. Altered Notch signaling hereby plays a key role for tumor cell survival and coping with a broad spectrum of vital issues, contributing to failed therapies, poor patient outcome, and loss of lives.

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.

Notch in Head and Neck Cancer

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

Three-Dimensional Imaging and Gene Expression Analysis Upon Enzymatic Isolation of the Tongue Epithelium

The tongue is a complex organ involved in a variety of functions such as mastication, speech, and taste sensory function. Enzymatic digestion techniques have been developed to allow the dissociation of the epithelium from the connective tissue of the tongue. However, it is not clear if the integrity and three-dimensional architecture of the isolated epithelium is preserved, and, furthermore if this tissue separation technique excludes its contamination from the mesenchymal tissue. Here, we first describe in detail the methodology of tongue epithelium isolation, and thereafter we analyzed the multicellular compartmentalization of the epithelium by three-dimensional fluorescent imaging and quantitative real-time PCR. Molecular characterization at both protein and transcript levels confirmed the exclusive expression of epithelial markers in the isolated epithelial compartment of the tongue. Confocal imaging analysis revealed that the integrity of the epithelium was not affected, even in the basal layer, where areas of active cell proliferations were detected. Therefore, the preservation of both the architecture and the molecular signature of the tongue epithelium upon enzymatic tissue separation enable further cellular, molecular and imaging studies on the physiology, pathology, and regeneration of the tongue.

Effects of Low Molecular Weight Fucoidan on the Proliferation and Apoptosis of Dysplastic Oral Keratinocyte and Oral Squamous Cell Carcinoma Cells

Oral squamous cell carcinoma (OSCC) is one of the most common malignant tumors with high incidence, rapid progress, and high mortality. There are still some defects in the treatments of OSCC, which seriously affect the quality of patients’ life. Therefore, it is urgent to find a safer and more effective treatment for OSCC. Low molecular weight fucoidan (LMWF) has various biological activities, such as antitumor, anti-inflammatory, and antithrombotic, and has no obvious side effects, but the effect of LMWF on OSCC has not been reported. In this study, the effects of LMWF on dysplastic oral keratinocyte (DOK) and OSCC cells SCC-9 and SCC-25 were detected by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, flow cytometry, TUNEL, colony formation, and wound healing assay, and the expression levels of Notch-1 and Jagged-1 treated with LMWF were detected by RT-qPCR. The results showed that LMWF could inhibit the proliferation and migration of DOK and SCC-9, and promote apoptosis. Low molecular weight fucoidan upregulated the expression of Notch-1 and Jagged-1 in DOK and SCC-9 cells. It indicated that LMWF might promote the apoptosis of DOK and SCC-9 by upregulating the Notch signal pathway, thereby inhibiting cell proliferation and playing an antitumor role. It provided theoretical basis to develop LMWF as a novel therapeutic drug for oral cancer.

Targeting Telomeres and Telomerase: Studies in Aging and Disease Utilizing CRISPR/Cas9 Technology

Telomeres and telomerase provide a unique and important avenue of study in improving both life expectancy and quality of life due to their close association with aging and disease. While major advances in our understanding of these two biological mediators have characterized the last two decades, previous studies have been limited by the inability to affect change in real time within living cells. The last three years, however, have witnessed a huge step forward to overcome this limitation. The advent of the clustered regularly interspaced short palindromic repeats/CRISPR-associated (CRISPR/Cas) system has led to a wide array of targeted genetic studies that are already being employed to modify telomeres and telomerase, as well as the genes that affect them. In this review, we analyze studies utilizing the technology to target and modify telomeres, telomerase, and their closely associated genes. We also discuss how these studies can provide insight into the biology and mechanisms that underlie aging, cancer, and other diseases.