Synergistic association of Notch and NFκB signaling and role of Notch signaling in modulating epithelial to mesenchymal transition in colorectal adenocarcinoma

Mitochondrial function and gastrointestinal diseases

Mitochondria are dynamic organelles that function in cellular energy metabolism, intracellular and extracellular signalling, cellular fate and stress responses. Mitochondria of the intestinal epithelium, the cellular interface between self and enteric microbiota, have emerged as crucial in intestinal health. Mitochondrial dysfunction occurs in gastrointestinal diseases, including inflammatory bowel diseases and colorectal cancer. In this Review, we provide an overview of the current understanding of intestinal epithelial cell mitochondrial metabolism, function and signalling to affect tissue homeostasis, including gut microbiota composition. We also discuss mitochondrial-targeted therapeutics for inflammatory bowel diseases and colorectal cancer and the evolving concept of mitochondrial impairment as a consequence versus initiator of the disease.

Molecular mechanisms of COVID-19-induced pulmonary fibrosis and epithelial-mesenchymal transition

As the outbreak of COVID-19 caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) first broke out in Hubei Province, China, at the end of 2019. It has brought great challenges and harms to global public health. SARS-CoV-2 mainly affects the lungs and is mainly manifested as pulmonary disease. However, one of the biggest crises arises from the emergence of COVID-19-induced fibrosis. At present, there are still many questions about how COVID-19 induced pulmonary fibrosis (PF) occurs and how to treat and regulate its long-term effects. In addition, as an important process of fibrosis, the effect of COVID-19 on epithelial-mesenchymal transition (EMT) may be an important factor driving PF. This review summarizes the main pathogenesis and treatment mechanisms of COVID-19 related to PF. Starting with the basic mechanisms of PF, such as EMT, transforming growth factor-β (TGF-β), fibroblasts and myofibroblasts, inflammation, macrophages, innate lymphoid cells, matrix metalloproteinases and tissue inhibitors of metalloproteinases, hedgehog pathway as well as Notch signaling. Further, we highlight the importance of COVID-19-induced EMT in the process of PF and provide an overview of the related molecular mechanisms, which will facilitate future research to propose new clinical therapeutic solutions for the treatment of COVID-19-induced PF.

Krüppel-like factors in tumors: Key regulators and therapeutic avenues

Krüppel-like factors (KLFs) are a group of DNA-binding transcriptional regulators with multiple essential functions in various cellular processes, including proliferation, migration, inflammation, and angiogenesis. The aberrant expression of KLFs is often found in tumor tissues and is essential for tumor development. At the molecular level, KLFs regulate multiple signaling pathways and mediate crosstalk among them. Some KLFs may also be molecular switches for specific biological signals, driving their transition from tumor suppressors to promoters. At the histological level, the abnormal expression of KLFs is closely associated with tumor cell stemness, proliferation, apoptosis, and alterations in the tumor microenvironment. Notably, the role of each KLF in tumors varies according to tumor type and different stages of tumor development rather than being invariant. In this review, we focus on the advances in the molecular biology of KLFs, particularly the regulations of several classical signaling pathways by these factors, and the critical role of KLFs in tumor development. We also highlight their strong potential as molecular targets in tumor therapy and suggest potential directions for clinical translational research.

COVID-19 and fibrosis: Mechanisms, clinical relevance, and future perspectives

Coronavirus 2019 (COVID-19), caused by severe acute respiratory syndrome-coronavirus 2 (SARS-CoV-2) has had significant impacts worldwide since its emergence in December, 2019. Despite a high recovery rate, there is a growing concern over its residual, long-term effects. However, because of a lack of long-term data, we are still far from establishing a consensus on post-COVID-19 complications. The deposition of excessive extracellular matrix (ECM), known as fibrosis, has been observed in numerous survivors of COVID-19. Given the exceptionally high number of individuals affected, there is an urgent need to address the emergence of fibrosis post-COVID-19. In this review, we discuss the clinical relevance of COVID-19-associated fibrosis, the current status of antifibrotic agents, novel antifibrotic targets, and challenges to its management.

Screening of four key genes in esophageal carcinoma based on TCGA and GEO data and verification of anti-proliferative effect of LAPTM4B knockdown in esophageal carcinoma cells invitro

Esophageal carcinoma (ESCA) is one of the most prevalent and aggressive malignancies of the gastrointestinal tract and constitutes sixth primary cause of cancer-related death worldwide. It is urgently needed to identify effective therapeutic targets. Differentially expressed genes (DEGs) involved in ESCA were identified via bioinformatics analysis. Four DEGs were selected for further analysis using Gene Expression Profiling Interactive Analysis, Human Protein Atlas, UALCAN web portal, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis. 5-ethynyl-2'-deoxyuridine incorporation and cell counting kit-8 assays were used to evaluate cell proliferation. Western blot analysis was used to detect the protein levels of lysosomal-associated transmembrane protein 4B (LAPTM4B), Notch1, hairy and enhancer of split 1 (Hes1), and hairy and enhancer of split-related with YRPW motif 1 (Hey1). Results showed that LAPTM4B, Bcl-2 homology domain 3 (BH3)-interacting domain death agonist (BID), epithelial cell transforming sequence 2 (ECT2), and aurora kinase A (AURKA) were upregulated in several types of tumors including ESCA and correlated with tumor stage and tumor histology based on bioinformatics analysis. KEGG pathway analysis suggested that LAPTM4B-associated genes were significantly enriched in Notch pathway. Meanwhile, BID-, ECT2-, and AURKA-correlated genes were particularly enriched in p53 signaling pathway. Additionally, we found that LAPTM4B silencing inhibited cell proliferation and Notch pathway in ESCA cells. Notch1 overexpression abrogated LAPTM4B knockdown-induced proliferation reduction in ESCA cells. In conclusion, LAPTM4B silencing inhibited proliferation in ESCA cells by inactivating the Notch pathway.

Notch signaling activation contributes to paclitaxel-induced neuropathic pain via activation of A1 astrocytes

Paclitaxel-induced neuropathic pain (PINP) is a progressive and refractory side effect of chemotherapy with few effective treatments at present. It is well-established that astrocytes activation contributes to the development of PINP. Recent reports showed astrocytes can be divided into A1 and A2 phenotypes. However, whether the transformation of astrocytes participates in PINP and the underlying mechanisms remain unknown. As Notch signaling pathway have shown to be involved in neuropathic pain, we aimed to investigate the relationship between Notch signaling pathway and A1 astrocytes in PINP. Herein we found that both A1 astrocytes and Notch signaling were markedly activated in the spinal cord of PINP rats and the downstream molecules of Notch signaling were colocalized with A1 astrocytes. DAPT (an inhibitor of Notch signaling) not only suppressed the mechanical allodynia of PINP rats, but also inhibited the activation of Notch signaling pathway and A1 astrocytes. Furthermore, Jagged1 (a ligand of Notch1 receptors) dose-dependently induced mechanical hyperalgesia in naïve rats and simultaneously led to Notch signaling activation and A1 astrocytes transformation, all of which were inhibited by DAPT. Taken together, these results demonstrate Notch signaling activation contributes to PINP via A1 astrocytes activation, which provides a promising therapeutic target for PINP.

Notch Signaling in Vascular Endothelial Cells, Angiogenesis, and Tumor Progression: An Update and Prospective

The Notch signaling pathway plays an essential role in a wide variety of biological processes including cell fate determination of vascular endothelial cells and the regulation of arterial differentiation and angiogenesis. The Notch pathway is also an essential regulator of tumor growth and survival by functioning as either an oncogene or a tumor suppressor in a context-dependent manner. Crosstalk between the Notch and other signaling pathways is also pivotal in tumor progression by promoting cancer cell growth, migration, invasion, metastasis, tumor angiogenesis, and the expansion of cancer stem cells (CSCs). In this review, we provide an overview and update of Notch signaling in endothelial cell fate determination and functioning, angiogenesis, and tumor progression, particularly in the development of CSCs and therapeutic resistance. We further summarize recent studies on how endothelial signaling crosstalk with the Notch pathway contributes to tumor angiogenesis and the development of CSCs, thereby providing insights into vascular biology within the tumor microenvironment and tumor progression.

The clinical significance of Notch1 immunoexpression in Caucasian patients with colorectal adenocarcinoma

Introduction

Colorectal cancer (CRC) is traditionally regarded as the most commonly diagnosed gastrointestinal malignant disease. Nevertheless, despite advances in diagnosis and novel therapeutic options, the clinical outcomes of patients are still not satisfactory.

Aim

To investigate the clinicopathological and prognostic roles of Notch1 expression, the immunohistochemical investigation was performed in samples of CRC tumour tissues, adjacent non-pathological mucosa, and metastatic foci in regional lymph nodes in Caucasian patients.

Material and methods

Paraffin-embedded adenocarcinoma samples were assessed immunohistochemically for Notch1 protein and scored according to the percentage of cells with a positive reaction combined with staining intensity. Connections between Notch1 immunoexpression and clinicopathological factors including the 5-year overall survival (OS) were evaluated.

Results

The level of the Notch1 immunohistochemical reactivity was correlated with the grade of the histological differentiation, size of the primary tumour, regional lymph node involvement, and perineural invasion (all p < 0.001). Kaplan-Meier survival analysis showed that the survival time for patients with a low expression of Notch1 was significantly longer than that for patients with moderate or strong level of Notch1 immunoreactivity (p < 0.001).

Conclusions

The enhanced level of Notch1 immunoexpression was significantly associated with malignancy-related clinicopathological factors and reduced the 5-year overall survival in CRC patients.

Adipose mesenchymal stem cell transplantation alleviates spinal cord injury-induced neuroinflammation partly by suppressing the Jagged1/Notch pathway

BACKGROUND

The therapeutic effects of adipose-derived mesenchymal stem cell (ADSC) transplantation have been demonstrated in several models of central nervous system (CNS) injury and are thought to involve the modulation of the inflammatory response. However, the exact underlying molecular mechanism is poorly understood. Activation of the Jagged1/Notch signaling pathway is thought to involve inflammatory and gliotic events in the CNS. Here, we elucidated the effect of ADSC transplantation on the inflammatory reaction after spinal cord injury (SCI) and the potential mechanism mediated by Jagged1/Notch signaling pathway suppression.

METHODS

To evaluate the therapeutic effects of ADSC treatment and the potential inhibitory effects of ADSCs on Notch signaling, mice were subjected to contusion SCI, and GFP-labeled ADSCs were injected into the lesion site immediately after the injury. Locomotor function, spinal cord tissue morphology, and the levels of Notch-related proteins and proinflammatory transcripts were compared between groups. To validate the hypothesis that the therapeutic effects of ADSCs are partly due to Notch1 signaling inhibition, a Jagged1 small interfering RNA (siRNA) was injected into the spinal cord to knock down Jagged1/Notch signaling. Neuronal staining and analyses of microglia/macrophage activation and signaling pathways were performed.

RESULTS

We demonstrated that ADSCs survived in the injured spinal cord for at least 28 days without differentiating into glial or neuronal elements. ADSC treatment resulted in significant downregulation of proinflammatory mediator expression and reduced ionized calcium-binding adapter molecule 1 (IBA1) and ED-1 staining in the injured spinal cord, eventually improving functional recovery. The augmentation of the Jagged1/Notch signaling pathway after SCI was suppressed by ADSC transplantation. The inhibition of the Jagged1/Notch signaling pathway by Jagged1 siRNA resulted in decreases in SCI-induced proinflammatory cytokines and the activation of microglia and an increase in the survival of neurons. Furthermore, Jagged1 knockdown suppressed the phosphorylation of JAK/STAT3 in astrocytes following SCI.

CONCLUSION

The results of this study demonstrated that the therapeutic effects of ADSCs in SCI mice were partly due to Jagged1/Notch signaling pathway inhibition and a subsequent reduction in JAK/STAT3 phosphorylation in astrocytes.

The hedgehog pathway regulates cancer stem cells in serous adenocarcinoma of the ovary

PURPOSE

Signaling by cancer stem cells (CSCs) is known to occur at least in part through conserved developmental pathways. Here, the role of one of these pathways, i.e., the hedgehog pathway, was evaluated in high-grade serous ovarian carcinoma (HGSOC).

METHODS AND RESULTS

We found that in HGSOC, hedgehog inhibitors (HHIs) GANT61, LDE225 and GDC0449 reduced or inhibited the formation of spheroids enriched in CSCs. Primary malignant cells (PMCs) in ascites from HGSOC patients cultured in the presence of HHIs showed significant reduction in CSCs. Sonic hedgehog (SHH) significantly increased the expression of ALDH1A1, which was inhibited by GANT61. In the presence of a SHH neutralizing antibody (5E1), a significant reduction in the number of spheroids was observed in HGSOC-derived cell lines. Further, the motility, migration and clonogenic growth of the cells were significantly reduced by HHIs. In the presence of GANT61, a reduction of cells from PMCs in the G0 phase of the cell cycle was observed. The magnitude of difference in expression of Gli1 in tumors from the same HGSOC patients at presentation and at interval debulking surgery was greater in patients who had a recurrence on follow up. GANT61 also significantly inhibited the growth of CSCs in nude mice. Finally, RNA sequencing of HGSOC cells treated with GANT61 showed a significantly reduced expression of CSC markers.

CONCLUSIONS

Our results indicate that the hedgehog pathway plays an important role in maintaining the integrity of CSCs in HGSOC and could be a potential therapeutic target.

Colorectal cancer (CRC) as a multifactorial disease and its causal correlations with multiple signaling pathways

Colorectal cancer (CRC) is the third most common malignancy and one of the leading causes of cancer-related death among men worldwide. CRC is a multifactor digestive pathology, which is a huge problem faced not only by clinicians but also by researchers. Importantly, a unique feature of CRC is the dysregulation of molecular signaling pathways. To date, a series of reviews have indicated that different signaling pathways are disordered and have potential as therapeutic targets in CRC. Nevertheless, an overview of the function and interaction of multiple signaling pathways in CRC is needed. Therefore, we summarized the pathways, biological functions and important interactions involved in CRC. First, we investigated the involvement of signaling pathways, including Wnt, PI3K/Akt, Hedgehog, ErbB, RHOA, Notch, BMP, Hippo, AMPK, NF-κB, MAPK and JNK. Subsequently, we discussed the biological function of these pathways in pathophysiological aspects of CRC, such as proliferation, apoptosis and metastasis. Finally, we summarized important interactions among these pathways in CRC. We believe that the interaction of these pathways could provide new strategies for the treatment of CRC.

Effect of miR‑449a‑mediated Notch signaling pathway on the proliferation, apoptosis and invasion of papillary thyroid carcinoma cells

The present study aimed to investigate the effect of miR‑449a‑mediated Notch signaling pathway on the proliferation, apoptosis and invasion of papillary thyroid carcinoma cells. Human papillary thyroid carcinoma cell line TPC‑1 was selected, and cells were grouped and transfected: Control group (without any treatment), negative control (NC) group (transfection with NC plasmid), miR‑449a mimic group (transfection with miR‑449a mimic), miR‑449a inhibitor group (transfection with miR‑449a inhibitor), DAPT group (addition of γ‑secretase inhibitor DAPT to inhibit the Notch signaling pathway), and miR‑449a inhibitor + DAPT group (transfection with miR‑449a inhibitor and addition of DAPT). The target relationship between miR‑449a and Notch1 was detected by dual‑luciferase reporter assay. qRT‑PCR and western blotting were used to assess the expression of miR‑449a, Notch1 and Jagged1 in cells. Cell proliferation was detected using EdU; the cell cycle and apoptosis were detected by flow cytometry; cell invasion ability was detected by Transwell assay. PCNA, MMP‑2, MMP‑9, Bcl‑2 and Bax mRNA and protein expression were assessed by qRT‑PCR and western blotting. The results revealed that miR‑449a negatively regulated Notch1. Compared with the control group, there was significantly increased miR‑449a expression in the miR‑449a mimic group, and there was significantly decreased expression of Notch1, Jagged1, PCNA, MMP‑2, MMP‑9 and Bcl‑2, increased Bax, reduced cell proliferation, increased G1‑phase cell fraction, decreased S‑phase cell fraction, an increased apoptosis rate, and decreased invasion ability in the miR‑449a mimic group and DAPT group (all P<0.05). However, the results in the miR‑449a inhibitor group were the opposite of those in miR‑449a mimic group (all P<0.05). There was no significant difference in cell proliferation, apoptosis and invasion in the NC group and miR‑449a inhibitor + DAPT group compared to the control group (all P>0.05). miR‑449a overexpression can inhibit Notch signaling pathway, thereby inhibiting the proliferation and invasion of papillary thyroid carcinoma cells and promoting cell apoptosis.

Blocking Notch signal pathway suppresses the activation of neurotoxic A1 astrocytes after spinal cord injury

Spinal cord injury (SCI) is a catastrophic disease which has complicated pathogenesis including inflammation, oxidative stress and glial scar formation. Astrocytes are the most abundant cells in central nervous system and fulfill homeostatic functions. Recent studies have described a new reactive phenotype of astrocytes, A1, induced by inflammation, which may have negative effects in SCI. As the Notch signaling pathway has been linked to cell differentiation and inflammation, we aimed to investigate its potential role in the differentiation of astrocytes in SCI. Contusive SCI rat model showed elevated A1 astrocyte numbers at the damage site 28 days after SCI and the expression levels of Notch signaling and its downstream genes were upregulated parallelly. Western blotting, RT-qPCR and immunofluorescence revealed that blocking of Notch pathway using γ-secretase blocker (DAPT) suppressed the differentiation of A1 astrocytes. Flow cytometry, and TUNEL staining indicated that DAPT alleviated neuronal apoptosis and axonal damage caused by A1 astrocytes likely through the Notch-dependent release of pro-inflammatory factors. CO-IP and western blotting revealed an interaction between Notch pathway and signal transducer and activator of transcription 3 (Stat3), which played a vital role in differentiation of A1 astrocytes. We conclude that phenotypic transition of A1 astrocytes and their neurotoxity were controlled by the Notch-Stat3 axis and that Notch pathway in astrocytes may serve as a promising therapeutic target for SCI.

GIT1 regulates angiogenic factor secretion in bone marrow mesenchymal stem cells via NF-κB/Notch signalling to promote angiogenesis

Objectives

Osteogenesis is coupled with angiogenesis during bone remodelling. G‐protein‐coupled receptor (GPCR) kinase 2‐interacting protein‐1 (GIT1) is an important protein that participates in fracture healing by regulating angiogenesis. This study investigated whether GIT1 could affect bone mesenchymal stem cells (BMSCs) to secrete angiogenic factors to enhance fracture healing by promoting angiogenesis and its possible mechanism.

Materials and methods

The angiogenesis of mice post‐fracture was detected by micro‐CT and immunofluorescence. Subsequently, vascular endothelial growth factor (VEGF) level in mouse and human BMSCs (hBMSCs) under TNF‐α stimulation was detected. The hBMSCs were transfected with GIT1 shRNAs to further explore the relationship between GIT1 and VEGF and angiogenesis in vitro. Furthermore, based on previous research on GIT1, possible signal pathways were investigated.

Results

GIT1 knockout mice exhibited impaired angiogenesis and delayed fracture healing. And GIT1 deficiency remarkably reduced the expression of VEGF mRNA in BMSCs, which affected the proliferation and migration of human umbilical vein endothelial cells. GIT1 knockdown inhibited the activation of Notch and NF‐κB signals by decreasing nuclear transportation of NICD and P65/P50, respectively. Overexpression of the canonical NF‐κB subunits P65 and P50 markedly increased NICD‐dependent activation of recombination signal‐binding protein‐jκ reporter. Finally, GIT1 enhanced the affinity of NF‐κB essential modulator (NEMO) for K63‐linked ubiquitin chains via interaction with NEMO coiled‐coil 2 domains.

Conclusion

These data revealed a positive role for GIT1 by modulating the Notch/NF‐κB signals which promoting paracrine of BMSCs to enhance angiogenesis and fracture healing.

Upregulation of MicroRNA 711 Mediates HIV-1 Vpr Promotion of Kaposi's Sarcoma-Associated Herpesvirus Latency and Induction of Pro-proliferation and Pro-survival Cytokines by Targeting the Notch/NF-κB-Signaling Axis

Coinfection with HIV-1 and Kaposi's sarcoma-associated herpesvirus (KSHV) often leads to AIDS-related malignancies, including Kaposi's sarcoma (KS) and primary effusion lymphoma (PEL). The interaction between HIV and KSHV plays a pivotal role in the progression of these malignancies. We have previously demonstrated that, by upregulating miR-942-5p, HIV-1 viral protein R (Vpr) inhibits KSHV lytic replication by targeting IκBα to activate the NF-κB signaling (Q. Yan, C. Shen, J. Qin, W. Li, M. Hu, H. Lu, D. Qin, J. Zhu, S. J. Gao, C. Lu, J Virol 90:8739-8753, 2016). Here, we show that Vpr inactivates Notch signaling, resulting in inhibition of KSHV lytic replication and induction of pro-proliferative and -survival cytokines, including interleukin-2 (IL-2), TIMP-1, IGF-1, and NT-4. Mechanistically, Vpr upregulates miR-711, which directly targets the Notch1 3' untranslated region. Suppression of miR-711 relieved Notch1 and reduced Vpr inhibition of KSHV lytic replication and Vpr induction of pro-proliferation and -survival cytokines, while overexpression of miR-711 exhibited the opposite effect. Finally, overexpression of Notch1 reduced Vpr induction of NF-κB activity by promoting IκBα promoter activity. Our novel findings reveal that by upregulating miR-711 to target Notch1, Vpr silences Notch signaling to activate the NF-κB pathway by reducing IκBα expression, leading to inhibition of KSHV lytic replication and induction of pro-proliferation and -survival cytokines. Therefore, the miR-711/Notch/NF-κB axis is important in the pathogenesis of AIDS-related malignancies and could be an attractive therapeutic target.IMPORTANCE HIV-1 infection significantly increases the risk of KS and PEL in KSHV-infected individuals. Our previous study has shown that HIV-1 Vpr regulates the KSHV life cycle by targeting IκBα to activate NF-κB signaling through upregulating cellular miR-942-5p. In this study, we have further found that Vpr inactivates Notch signaling to promote KSHV latency and production of pro-proliferation and -survival cytokines. Another Vpr-upregulated cellular microRNA, miR-711, participates in this process by directly targeting Notch1. As a result, Notch1 upregulation of the IκBα promoter activity is attenuated, resulting in reduced levels of IκBα transcript and protein. Overall, these results illustrate an alternative mechanism of HIV-1 Vpr regulation of KSHV latency and aberrant cytokines through the miR-711/Notch/NF-κB axis. Our novel findings further demonstrate the role of an HIV-1-secreted regulatory protein in the KSHV life cycle and KSHV-related malignancies.

Suppression of Notch1 and AKT mediated epithelial to mesenchymal transition by Verrucarin J in metastatic colon cancer

Epithelial to mesenchymal transition (EMT) in colorectal cancer (CRC) has been attributed to activation of AKT and Notch1 signaling pathways. As EMT corresponds to increased aggressiveness of CRC, approaches that prevent metastasis by targeting AKT/Notch1 pathways are at the forefront of current research paradigms. This study examined the anti-metastatic potential of Verrucarin J (VJ), a small molecule, in CRC cells overexpressing AKT and Notch1. VJ significantly inhibited AKT/HCT 116 cell growth by acting on the AKT/NFκB/Bcl-2 signaling axis and initiated apoptotic signaling as was evident from increased expression of pro-apoptotic markers such as cleaved PARP, cleaved caspase 3, and cleaved caspase 9. Also, VJ inhibited the cell growth in AKT/Notch1-overexpressing CRC cells and abrogated EMT. The down-regulation of AKT and Notch1 signaling was apparent in immunoblot analysis and corresponded with down-regulation of mesenchymal markers including Snail, and β-catenin. Intraperitoneal administration of VJ in control (pCMV/HCT 116) and AKT/HCT 116 mice significantly suppressed AKT-induced tumor growth in a xenograft model. In addition, down-regulation of prosurvival markers as well as AKT and Notch1 was observed in the immunohistochemical analysis of the xenografted tumors. In conclusion, our study substantiates the role of AKT and Notch1 in cell proliferation, angiogenesis, and EMT of CRC cells and demonstrates that VJ may be a viable therapeutic option to counter AKT-induced cell proliferation and tumor outgrowth in CRC.

Common profiles of Notch signaling differentiate disease-free survival in luminal type A and triple negative breast cancer

Breast cancer (BC) is characterized by high heterogeneity regarding its biology and clinical characteristics. The Notch pathway regulates such processes as organ modeling and epithelial-to-mesenchymal transition (EMT).

The aim of the study was to determine the effect of differential expression of Notch members on disease-free survival (DFS) in luminal type A (lumA) and triple negative (TN) BC.

The differential expression of 19 Notch members was examined in a TCGA BC cohort. DFS analysis was performed using the log-rank test (p<0.05). Biological differences between DFS groups were determined with Gene Set Enrichment Analysis (GSEA) (tTest, FDR<0.25). Common expression profiles according to Notch signaling were examined using ExpressCluster (K-means, mean centered, Euclidean distance metric).

The overexpression of HES1, LFNG and PSEN1 was found to be favorable for DFS in lumA, and lowered expression favorable for DFS in TN.

GSEA analysis showed that differential Notch signaling is associated with cell cycle, tissue architecture and remodeling. Particularly, targets of E2F, early stage S phase transcription factor, were upregulated in the lumA unfavorable group and the TN favorable group differentiated on a basis of HES1 and PSEN1 expression.

Summarizing, our analysis show significance of Notch signaling in BRCA progression through triggering EMT. Moreover, identification of numerous genes which overexpression is associated with disease recurrence may serve as a source of potential targets for a new anticancer therapy.

Notch1 is a prognostic factor that is distinctly activated in the classical and proneural subtype of glioblastoma and that promotes glioma cell survival via the NF-κB(p65) pathway

Glioblastomas (GBMs) are the most prevalent and devastating primary intracranial malignancies and have extensive heterogeneity. Notch1 signaling is a more complex process in the development of numerous cell and tissue types, including gliomagenesis and progression, and is upregulated in glioma-initiating cells. However, the contradictory expression of Notch1 among lower grade gliomas and GBMs confounds our understanding of GBM biology and has made identifying effective therapies difficult. In this study, we validated that Notch1 and NF-κB(p65) are highly expressed in the classical and proneural subtypes of GBM using the data set from The Cancer Genome Atlas (TCGA) and the Chinese Glioma Genome Atlas (CGGA). DAPT and shRNA targeting Notch1 decreased NF-κB(p65) expression, suppressed cell proliferation, and induced apoptosis of GBM cells in vitro and in vivo. Furthermore, we illustrated that the intracellular Notch could bind with NF-κB(p65) in GBM cells. These findings suggest that the cross-talk between Notch1 signaling and NF-κB(p65) could contribute to the proliferation and apoptosis of glioma, and this discovery could help drive the design of more effective therapies in Notch1-targeted clinical trials.

Notch and its oncogenic activity in human malignancies

BACKGROUND

Increasing evidence has demonstrated that Notch signaling is deregulated in human hematological malignancies and solid tumors. This signaling has a protumorigenic effect but may also act as a tumor suppressor. How induction of a single pathway gives rise to the opposite effects in different cell types is still unknown.

METHODS

This review article includes available data from peer-reviewed publications associated with the role of Notch signaling during cancer pathogenesis.

RESULTS

Numerous reports have indicated that alterations in Notch signaling and its oncogenic activity were originally associated with the pathogenesis of T‑cell acute lymphoblastic leukemia/lymphoma (T-ALL), an aggressive hematologic tumor affecting children and adolescents. The possibility that Notch could play a significant role in human breast cancer development comes from studies on mouse mammary tumor virus-induced cancer. Numerous findings over the past several years have indicated that alterations in Notch signaling are also responsible for ovarian cancer development. Mention should also be made of the connection between expression of Notch 3 and increased resistance to chemotherapy, which remains a major obstacle to successful treatment. Notch as an oncogenic factor is also involved in the development of colon cancer, lung carcinoma and Kaposi's sarcoma.

CONCLUSION

Notch is a binary cell fate determinant and its overexpression has been described as oncogenic in a wide array of human malignancies. This finding led to interest in therapeutically targeting this pathway, especially by the use of gamma-secretase inhibitors (GSIs) blocking the cleavage of Notch receptors at the cell membrane by the inhibition of Notch intracellular domain (NICD) releasing. Preclinical cancer models have revealed that GSIs suppress the growth of cancers such as pancreatic, breast and lung cancer.

Sclareolide enhances gemcitabine‑induced cell death through mediating the NICD and Gli1 pathways in gemcitabine‑resistant human pancreatic cancer

Pancreatic cancer is a type of cancer, which rapidly develops resistance to chemotherapy. Gemcitabine is the treatment used clinically, however, gemcitabine resistance leads to limited efficacy and patient survival rates of only a few months following diagnosis. The aim of the present study was to investigate the mechanisms underlying gemcitabine resistance in pancreatic cancer and to select targeted agents combined with gemcitabine to promote the treatment of pancreatic cancer. Panc-1 and ASPC-1 human pancreatic cancer cells (HPCCs) were used to establish the experimental model, and HPCCs were exposed to gemcitabine of serially increased concentrations to generate gemcitabine-resistant cells (GR-HPCCs). The anticancer effect of gemcitabine combined with sclareolide was then assessed. Epithelial to mesenchymal transition (EMT), human equilibrative nucleoside transporter 1 (hENT1) and ribonucleoside diphosphate reductase 1 (RRM1) were detected in the HPCCs and GR-HPCCs, and the mechanisms were investigated. Sclareolide resensitized the GR-HPCCs to gemcitabine. The expression levels of hENT1 and RRM1 were lower and higher, respectively, in GR-HPCCs, compared with HPCCs. Sclareolide upregulated hENT1, downregulated RRM1 and inhibited gemcitabine-induced EMT through the TWIST1/Slug pathway in the GR-HPCCs. In addition, sclareolide mediated the NOTCH 1 intracellular cytoplasmic domain (NICD)/glioma-associated oncogene 1 (Gli1) pathway, which triggered TWIST1/Slug-hENT1/RRM1 signaling and resensitized GR-HPCCs to gemcitabine. Finally, sclareolide resensitized GR-HPCCs to gemcitabine through inducing apoptosis; in vivo, the co-administraion of sclareolide and gemcitabine effectively suppressed tumor growth. Sclareolide may be a novel agent in combination with gemcitabine for the treatment of gemcitabine-resistant pancreatic cancer, which resensitizes GR-HPCCs to gemcitabine through mediating NICD and Gli1.

Diet-induced weight loss leads to a switch in gene regulatory network control in the rectal mucosa

BACKGROUND

Weight loss may decrease risk of colorectal cancer in obese individuals, yet its effect in the colorectum is not well understood. We used integrative network modeling, Passing Attributes between Networks for Data Assimilation, to estimate transcriptional regulatory network models from mRNA expression levels from rectal mucosa biopsies measured pre- and post-weight loss in 10 obese, pre-menopausal women.

RESULTS

We identified significantly greater regulatory targeting of glucose transport pathways in the post-weight loss regulatory network, including "regulation of glucose transport" (FDR=0.02), "hexose transport" (FDR=0.06), "glucose transport" (FDR=0.06) and "monosaccharide transport" (FDR=0.08). These findings were not evident by gene expression analysis alone. Network analysis also suggested a regulatory switch from NFΚB1 to MAX control of MYC post-weight loss.

CONCLUSIONS

These network-based results expand upon standard gene expression analysis by providing evidence for a potential mechanistic alteration caused by weight loss.

The Role of Notch1 Signaling in Anaplastic Thyroid Carcinoma

PURPOSE

The Notch signaling pathway is widely expressed in normal, reactive, and neoplastic tissues; however, its role in thyroid tissues has not been fully elucidated. Therefore, this study was conducted to characterize the expression of the Notch signaling pathway in papillary thyroid cancer (PTC) cells and anaplastic thyroid cancer (ATC) cells.

MATERIALS AND METHODS

Expression of activated Notch1 in ATC and PTC paraffin-embedded tissues was determined by immunohistochemistry. The small interfering RNA techniquewas employed to knock down Notch1 expression in ATC and PTC cell lines.

RESULTS

The expression of activated Notch1 was higher in ATC cases than in PTC cases. Inhibition of Notch1 significantly reduced proliferation and migration of ATC cells, but not PTC cells. In addition, inhibition of Notch1 in ATC cells significantly reduced the expression of key markers of epithelial-mesenchymal transition and cancer stem cells. Conversely, changes in the expression of these proteins were not observed in PTC cells.

CONCLUSION

The results of this study suggest that Notch1 expression plays different roles in tumor progression in ATC and PTC cells. We also found that Notch1 expression was significantly related to the highly invasive or proliferative activity of ATC cells.

Notch in fibrosis and as a target of anti-fibrotic therapy

The Notch pathway represents a highly conserved signaling network with essential roles in regulation of key cellular processes and functions, many of which are critical for development. Accumulating evidence indicates that it is also essential for fibrosis and thus the pathogenesis of chronic fibroproliferative diseases in diverse organs and tissues. Different effects of Notch activation are observed depending on cellular and tissue context as well as in both physiologic and pathologic states. Close interactions of Notch signaling pathway with other signaling pathways have been identified. In this review, current knowledge on the role of the Notch signaling with special focus on fibrosis and its potential as a therapeutic target is summarized.

PLCε knockdown inhibits prostate cancer cell proliferation via suppression of Notch signalling and nuclear translocation of the androgen receptor

Phospholipase Cε (PLCε), a key regulator of diverse cellular functions, has been implicated in various malignancies. Indeed, PLCε functions include cell proliferation, apoptosis and malignant transformation. Here, we show that PLCε expression is elevated in prostate cancer (PCa) tissues compared to benign prostate tissues. Furthermore, PLCε depletion using an adenovirally delivered shRNA significantly decreased cell growth and colony formation, arresting the PC3 and LNCaP cell lines in the S phase of the cell cycle. We also observed that PLCε was significantly correlated with Notch1 and androgen receptor (AR). Additionally, we demonstrate that the activation of both the Notch and AR signalling pathways is involved in PLCε-mediated oncogenic effects in PCa. Our findings suggest that PLCε is a putative oncogene and prognostic marker, potentially representing a novel therapeutic target for PCa.