The Notch pathway in cancer: differentiation gone awry

Signaling pathways in colorectal cancer implications for the target therapies

Colorectal carcinoma (CRC) stands as a pressing global health issue, marked by the unbridled proliferation of immature cells influenced by multifaceted internal and external factors. Numerous studies have explored the intricate mechanisms of tumorigenesis in CRC, with a primary emphasis on signaling pathways, particularly those associated with growth factors and chemokines. However, the sheer diversity of molecular targets introduces complexity into the selection of targeted therapies, posing a significant challenge in achieving treatment precision. The quest for an effective CRC treatment is further complicated by the absence of pathological insights into the mutations or alterations occurring in tumor cells. This study reveals the transfer of signaling from the cell membrane to the nucleus, unveiling recent advancements in this crucial cellular process. By shedding light on this novel dimension, the research enhances our understanding of the molecular intricacies underlying CRC, providing a potential avenue for breakthroughs in targeted therapeutic strategies. In addition, the study comprehensively outlines the potential immune responses incited by the aberrant activation of signaling pathways, with a specific focus on immune cells, cytokines, and their collective impact on the dynamic landscape of drug development. This research not only contributes significantly to advancing CRC treatment and molecular medicine but also lays the groundwork for future breakthroughs and clinical trials, fostering optimism for improved outcomes and refined approaches in combating colorectal carcinoma.

Immunogenicity of cancer cells: An overview

The immune system assumes a pivotal role in the organism's capacity to discern and obliterate malignant cells. The immunogenicity of a cancer cell pertains to its proficiency in inciting an immunological response. The prowess of immunogenicity stands as a pivotal determinant in the triumph of formulating immunotherapeutic methodologies. Immunotherapeutic strategies include immune checkpoint inhibitors, chimeric antigen receptor (CAR) T-cell therapy, and on vaccines. Immunogenic cell death (ICD) epitomizes a form of cellular demise that incites an immune response against dying cells. ICD is characterized by the liberation of distinct specific molecules that activate the immune system, thereby leading to the identification and elimination of dying cells by immunocytes. One of the salient characteristics inherent to the ICD phenomenon resides in the vigorous liberation of adenosine triphosphate (ATP) by cellular entities dedicated to embarking upon the process of programmed cell death, yet refraining from complete apoptotic demise. ICD is initiated by a sequence of molecular events that occur during cell death. These occurrences encompass the unveiling or discharge of molecules such as calreticulin, high-mobility group box 1 (HMGB1), and adenosine triphosphate (ATP) from dying cells. These molecules act as "eat me" signals, which are recognized by immune cells, thereby prompting the engulfment and deterioration of expiring cells by phagocytes including various pathways such as Necroptosis, Apoptosis, and pyroptosis. Here, we review our current understanding of the pathophysiological importance of the immune responses against dying cells and the mechanisms underlying their activation. Overall, the ICD represents an important mechanism by which the immune system recognizes and eliminates dying cells, including cancer cells. Understanding the molecular events that underlie ICD bears the potential to engender innovative cancer therapeutics that harness the power of the immune system to combat cancer.

Identifying Drug Targets of Oral Squamous Cell Carcinoma through a Systems Biology Method and Genome-Wide Microarray Data for Drug Discovery by Deep Learning and Drug Design Specifications

In this study, we provide a systems biology method to investigate the carcinogenic mechanism of oral squamous cell carcinoma (OSCC) in order to identify some important biomarkers as drug targets. Further, a systematic drug discovery method with a deep neural network (DNN)-based drug–target interaction (DTI) model and drug design specifications is proposed to design a potential multiple-molecule drug for the medical treatment of OSCC before clinical trials. First, we use big database mining to construct the candidate genome-wide genetic and epigenetic network (GWGEN) including a protein–protein interaction network (PPIN) and a gene regulatory network (GRN) for OSCC and non-OSCC. In the next step, real GWGENs are identified for OSCC and non-OSCC by system identification and system order detection methods based on the OSCC and non-OSCC microarray data, respectively. Then, the principal network projection (PNP) method was used to extract core GWGENs of OSCC and non-OSCC from real GWGENs of OSCC and non-OSCC, respectively. Afterward, core signaling pathways were constructed through the annotation of KEGG pathways, and then the carcinogenic mechanism of OSCC was investigated by comparing the core signal pathways and their downstream abnormal cellular functions of OSCC and non-OSCC. Consequently, HES1, TCF, NF-κB and SP1 are identified as significant biomarkers of OSCC. In order to discover multiple molecular drugs for these significant biomarkers (drug targets) of the carcinogenic mechanism of OSCC, we trained a DNN-based drug–target interaction (DTI) model by DTI databases to predict candidate drugs for these significant biomarkers. Finally, drug design specifications such as adequate drug regulation ability, low toxicity and high sensitivity are employed to filter out the appropriate molecular drugs metformin, gefitinib and gallic-acid to combine as a potential multiple-molecule drug for the therapeutic treatment of OSCC.

Identification of Pathologic Grading-Related Genes Associated with Kidney Renal Clear Cell Carcinoma

Background. Renal epithelium lesions can cause renal cell carcinoma. This kind of tumor is common among all renal cancers with poor prognosis, of which more than 70% belong to kidney renal clear cell carcinoma. As the pathogenesis of KIRC has not been elucidated, it is necessary to be further explored. Methods. The Genomic Spatial Event database was used to obtain the analysis dataset (GSE126964) based on the GEO database, and The Cancer Genome Atlas was applied for KIRC data collection. edgeR and limma analyses were subsequently conducted to identify differentially expressed genes. Based on the systems biology approach of WGCNA, potential biomarkers and therapeutic targets of this disease were screened after the establishment of a gene coexpression network. GO and KEGG enrichment used cluster Profiler, enrichplot, and ggplot2 in the R software package. Protein-protein interaction network diagrams were plotted for hub gene collection via the STRING platform and Cytoscape software. Hub genes associated with overall survival time of KIRC patients were ultimately identified using the Kaplan-Meier plotter. Results. There were 1863 DEGs identified in total and ten coexpressed gene modules discovered using a WGCNA method. GO and KEGG analysis findings revealed that the most enrichment pathways included Notch binding, cell migration, cell cycle, cell senescence, apoptosis, focal adhesions, and autophagosomes. Twenty-seven hub genes were identified, among which FLT1, HNRNPU, ATP6V0D2, ATP6V1A, and ATP6V1H were positively correlated with OS rates of KIRC patients ( $p<0.05$ ). Conclusions. In conclusion, bioinformatic techniques can be useful tools for predicting the progression of KIRC. DEGs are present in both KIRC and normal kidney tissues, which can be considered the KIRC biomarkers.

The Role of Membrane-Associated E3 Ubiquitin Ligases in Cancer

The cell membrane system comprises the plasma membrane, endoplasmic reticulum, Golgi apparatus, lysosome, mitochondria, and nuclear membrane, which are essential for maintaining normal physiological functions of cells. The proteins associated with these membrane-organelles are frequently modified to regulate their functions, the most common of which is ubiquitin modification. So far, many ubiquitin E3 ligases anchored in the membrane system have been identified as critical players facilitating intracellular biofunctions whose dysfunction is highly related to cancer. In this review, we summarized membrane-associated E3 ligases and revealed their relationship with cancer, which is of great significance for discovering novel drug targets of cancer and may open up new avenues for inducing ubiquitination-mediated degradation of cancer-associated membrane proteins via small chemicals such as PROTAC and molecular glue.

Antibody-Incorporated Nanomedicines for Cancer Therapy

Antibody-based cancer therapy, one of the most significant therapeutic strategies, has achieved considerable success and progress over the past decades. Nevertheless, obstacles including limited tumor penetration, short circulation half-lives, undesired immunogenicity, and off-target side effects remain to be overcome for the antibody-based cancer treatment. Owing to the rapid development of nanotechnology, antibody-containing nanomedicines that have been extensively explored to overcome these obstacles have already demonstrated enhanced anticancer efficacy and clinical translation potential. This review intends to offer an overview of the advancements of antibody-incorporated nanoparticulate systems in cancer treatment, together with the nontrivial challenges faced by these next-generation nanomedicines. Diverse strategies of antibody immobilization, formats of antibodies, types of cancer-associated antigens, and anticancer mechanisms of antibody-containing nanomedicines are provided and discussed in this review, with an emphasis on the latest applications. The current limitations and future research directions on antibody-containing nanomedicines are also discussed from different perspectives to provide new insights into the construction of anticancer nanomedicines.

Performance Assessment of the Network Reconstruction Approaches on Various Interactomes

Beyond the list of molecules, there is a necessity to collectively consider multiple sets of omic data and to reconstruct the connections between the molecules. Especially, pathway reconstruction is crucial to understanding disease biology because abnormal cellular signaling may be pathological. The main challenge is how to integrate the data together in an accurate way. In this study, we aim to comparatively analyze the performance of a set of network reconstruction algorithms on multiple reference interactomes. We first explored several human protein interactomes, including PathwayCommons, OmniPath, HIPPIE, iRefWeb, STRING, and ConsensusPathDB. The comparison is based on the coverage of each interactome in terms of cancer driver proteins, structural information of protein interactions, and the bias toward well-studied proteins. We next used these interactomes to evaluate the performance of network reconstruction algorithms including all-pair shortest path, heat diffusion with flux, personalized PageRank with flux, and prize-collecting Steiner forest (PCSF) approaches. Each approach has its own merits and weaknesses. Among them, PCSF had the most balanced performance in terms of precision and recall scores when 28 pathways from NetPath were reconstructed using the listed algorithms. Additionally, the reference interactome affects the performance of the network reconstruction approaches. The coverage and disease- or tissue-specificity of each interactome may vary, which may result in differences in the reconstructed networks.

When Viruses Cross Developmental Pathways

Aberrant regulation of developmental pathways plays a key role in tumorigenesis. Tumor cells differ from normal cells in their sustained proliferation, replicative immortality, resistance to cell death and growth inhibition, angiogenesis, and metastatic behavior. Often they acquire these features as a consequence of dysregulated Hedgehog, Notch, or WNT signaling pathways. Human tumor viruses affect the cancer cell hallmarks by encoding oncogenic proteins, and/or by modifying the microenvironment, as well as by conveying genomic instability to accelerate cancer development. In addition, viral immune evasion mechanisms may compromise developmental pathways to accelerate tumor growth. Viruses achieve this by influencing both coding and non-coding gene regulatory pathways. Elucidating how oncogenic viruses intersect with and modulate developmental pathways is crucial to understanding viral tumorigenesis. Many currently available antiviral therapies target viral lytic cycle replication but with low efficacy and severe side effects. A greater understanding of the cross-signaling between oncogenic viruses and developmental pathways will improve the efficacy of next-generation inhibitors and pave the way to more targeted antiviral therapies.

Nimbolide exerts protective effects in complete Freund's adjuvant induced inflammatory arthritis via abrogation of STAT-3/NF-κB/Notch-1 signaling

AIM

Activation of transmembrane Notch-1 receptors through inflammatory cytokines is highly regulated by STAT-3 and NF-κB phosphorylation. Nimbolide (NMB) exhibits potent anti-inflammatory, anti-fibrotic, anticancer activities by targeting various pathways. Here, we have investigated the effect of NMB in regulation of STAT-3/NF-κB/Notch-1 axis in complete Freund's adjuvant (CFA) induced inflammatory arthritis (IA) model.

MAIN METHODS

The anti-inflammatory and anti-arthritic activity of NMB was evaluated both in vitro (IL-1β stimulated HIG-82 synovial fibroblasts) and in vivo (CFA induced rat model of IA) models. In vitro anti-arthritic activity was assessed by anti-migratory effect, while in vivo effects were evaluated through radiological and histological analysis. The effect of NMB on STAT-3, NF-κB, Notch-1 signaling pathways and proinflammatory cytokines were studied using western blot, immunohistochemistry and ELISA methods. Key findings NMB attenuated the migration of synovial fibroblasts in vitro. It reduced the progression of arthritis as evidenced from the improved radiological and histological abnormalities in arthritic rats. NMB significantly suppressed the nitrosooxidative stress and levels of pro-inflammatory cytokines. NMB also exhibited remarkable protective activity against upregulation of MAPK, STAT-3 and NF-κB phosphorylation mediated Notch-1 signaling pathway in synovial tissue of arthritic rats.

SIGNIFICANCE

NMB may have clinical therapeutic value in rheumatoid arthritis by inhibiting STAT-3/NF-κB/Notch-1 axis and also by reducing the levels of proinflammatory cytokines.

N3ICD with the transmembrane domain can effectively inhibit EMT by correcting the position of tight/adherens junctions

EMT allows a polarized epithelium to lose epithelial integrity and acquire mesenchymal characteristics. Previously, we found that overexpression of the intracellular domain of Notch3 (N3ICD) can inhibit EMT in breast cancer cells. In this study, we aimed to elucidate the influence of N3ICD or N3ICD combined with the transmembrane domain (TD+N3ICD) on the expression and distribution of TJs/AJs and polar molecules. We found that although N3ICD can upregulate the expression levels of the above-mentioned molecules, TD+N3ICD can inhibit EMT more effectively than N3ICD alone. TD+N3ICD overexpression upregulated the expression of endogenous full-length Notch3 and contributed to correcting the position of TJs/AJs molecules and better acinar structures formation. Co-immunoprecipitation results showed that the upregulated endogenous full-length Notch3 could physically interact with E-ca in MDA-MB-231/pCMV-(TD+N3ICD) cells. Collectively, our data indicate that overexpression of TD+N3ICD can effectively inhibit EMT, resulting in better positioning of TJs/AJs molecules and cell-cell adhesion in breast cancer cells. Abbreviations: EMT: Epithelial-mesenchymal transition; TJs: Tight junctions; AJs: Adherens junctions; aPKC: Atypical protein kinase C; Crb: Crumbs; Lgl: Lethal (2) giant larvae; LLGL2: lethal giant larvae homolog 2; PAR: Partitioning defective; PATJ: Pals1-associated TJ protein.

DAPT, a γ-Secretase Inhibitor, Suppresses Tumorigenesis, and Progression of Growth Hormone-Producing Adenomas by Targeting Notch Signaling

Advances in the understanding of growth hormone-producing adenomas (GHomas) are ongoing, but current therapy is limited by moderate and variable efficacy and in need of life-long treatment. In this study, the molecular signaling pathway related to GHoma was investigated by proteomics and transcriptomics. The differentially expressed proteins and genes were significantly enriched in Extracellular Matrix-Receptor Interactions, Notch Signaling, Basal Cell Carcinoma Signaling, JAK-STAT3, Wnt Signaling, and Glioblastoma Multiforme Signaling by Ingenuity Pathway Analysis. Furthermore, the Notch2/Delta-like canonical Notch ligand (DLL) signaling pathway was identified to be associated with tumorigenesis and invasiveness of GHoma. In 76 patients, Notch2 and DLL3 were upregulated in invasive compared to those in non-invasive GHoma (p < 0.05). Disease-free survival was significantly longer in patients with low, compared with high, DLL3 expression (p = 0.027). Notch 2 knockdown inhibited cell migration in both GH3 cells and primary GHoma cells, along with downregulation of the mRNA expression of related genes. DAPT, a γ-secretase inhibitor, inhibited tumor growth and invasion in vivo and in vitro and suppressed the release of growth hormone in primary GHoma cells. The involvement of Notch2/DLL3 signaling in GHoma progression warrants additional study of Notch inhibitor, DAPT, as a potential GHoma treatment.

Solamargine inhibits proliferation and promotes apoptosis of CM-319 human chordoma cells through suppression of notch pathway

Background

Solamargine (SM), which represents a natural steroid alkaloid glycoside compound and a cytotoxic agent, has been proved to enhance the sensitivity of lung cancer cells to tumor necrosis factors (TNFs). In this study, we aimed to investigate the roles and mechanisms of SM in chordoma.

Methods

Cell viability, proliferation, apoptosis and cell cycle were measured by cell counting Kit-8 (CCK-8) assay, 5(6)-carboxyfluorescein diacetate succinimidyl ester (CFSE) labeling and flow cytometry (FCM), respectively. Western blot and quantitative real-time reverse transcription PCR (qRT-PCR) assays were performed to detect the expressions of related mRNAs and proteins.

Results

The results revealed that SM distinctly suppressed the proliferation of CM-319 cells. SM significantly induced the CM-319 cells apoptosis through up-regulating the expression levels of Caspase-3/8/9. The cell cycle of CM-319 cells was blocked by SM in G1 phase. Moreover, SM could significantly suppress the Notch pathway in CM-319 cells.

Conclusions

In conclusion, SM suppressed the proliferation and enhanced the apoptosis ability of CM-319 cells via suppressing the Notch pathway. The results suggested that SM might be a novel therapeutic agent and supported the utilization of SM in chordoma.

Targeted therapies in pancreatic cancer: Promises and failures

Pancreatic ductal adenocarcinoma (PDAC) is an incidence rate nearly equal to its mortality rate. The poor prognosis of the disease can be explained by the absence of effective biomarkers for screening and early detection, together with the aggressive behavior and resistance to the currently available chemotherapy. The therapeutic failure can also be attributed to the inter-/intratumor genetic heterogeneity and the abundance of tumor stroma that occupies the majority of the tumor mass. Gemcitabine is used in the treatment of PDAC; however, the response rate is less than 12%. A recent phase III trial revealed that the combination of oxaliplatin, irinotecan, fluorouracil, and leucovorin could be an option for the treatment of metastatic PDAC patients with good performance status, although these approaches can result in high toxicity level. Further investigations are required to develop innovative anticancer agents that either improve gemcitabine activity, within novel combinatorial approaches or acts with a better efficacy than gemcitabine. The aim of the current review is to give an overview of preclinical and clinical studies targeting key dysregulated signaling pathways in PDAC.

Antioxidant potential of ganoderic acid in Notch-1 protein in neuroblastoma

Neuroblastoma is a childhood tumor arising from developing a sympathetic nervous system and causes around 10% of pediatric tumors. Despite advancement in the use of sophisticated techniques in molecular biology, neuroblastoma patient's survivability rate is very less. Notch pathway is significant in upholding cell maintenance and developmental process of organs. Notch-1 proteins are a ligand-activated transmembrane receptor which decides the fate of the cell. Notch signaling leads to transcription of genes which indulged in numerous diseases including tumor progression. Ganoderic acid, a lanosterol triterpene, isolated from fungus Ganoderma lucidum with a wide range of medicinal values. In the present study, various isoforms of the ganoderic acid and natural inhibitors were docked by molecular docking using Maestro 9 in the Notch-1 signaling pathway. The receptor-based molecular docking exposed the best binding interaction of Notch-1 with ganoderic acid A with GScore (- 8.088), kcal/mol, Lipophilic EvdW (- 1.74), Electro (- 1.18), Glide emodel (- 89.944) with the active participation of Arg 189, Arg 199, Glu 232 residues. On the other hand natural inhibitor, curcumin has GScore (- 7.644), kcal/mol, Lipophilic EvdW (- 2.19), Electro (- 0.73), Glide emodel (- 70.957) with Arg 75 residues involved in docking. The ligand binding affinity of ganoderic acid A in Notch-1 is calculated using MM-GBSA (- 76.782), whereas curcumin has (- 72.815) kcal/mol. The QikProp analyzed the various drug-likeness parameters such as absorption, distribution, metabolism, excretion, and toxicity (ADME/T) and isoforms of ganoderic acid require some modification to fall under Lipinski rule. The ganoderic acid A and curcumin were the best-docked among different compounds and exhibits downregulation in Notch-1 mRNA expression and inhibits proliferation, viability, and ROS activity in IMR-32 cells.

An Analysis of Automated Visual Analysis Classification: Interactive Visualization Task Inference of Cancer Genomics Domain Experts

We show how mouse interaction log classification can help visualization toolsmiths understand how their tools are used "in the wild" through an evaluation of MAGI - a cancer genomics visualization tool. Our primary contribution is an evaluation of twelve visual analysis task classifiers, which compares predictions to task inferences made by pairs of genomics and visualization experts. Our evaluation uses common classifiers that are accessible to most visualization evaluators: -nearest neighbors, linear support vector machines, and random forests. By comparing classifier predictions to visual analysis task inferences made by experts, we show that simple automated task classification can have up to 73 percent accuracy and can separate meaningful logs from "junk" logs with up to 91 percent accuracy. Our second contribution is an exploration of common MAGI interaction trends using classification predictions, which expands current knowledge about ecological cancer genomics visualization tasks. Our third contribution is a discussion of how automated task classification can inform iterative tool design. These contributions suggest that mouse interaction log analysis is a viable method for (1) evaluating task requirements of client-side-focused tools, (2) allowing researchers to study experts on larger scales than is typically possible with in-lab observation, and (3) highlighting potential tool evaluation bias.

Expression of Notch receptors and their ligands in pancreatic ductal adenocarcinoma

Pancreatic cancer is the fourth leading cause of cancer-associated mortality in developed countries. Pancreatic ductal adenocarcinoma (PDAC) accounts for ~90% of all pancreatic cancer cases. The Notch signaling pathway serves a crucial role in embryonic development, as well as during the tumorigenesis of different types of cancer. However, Notch signaling serves either oncogenic or tumor suppressor roles depending on the tissue type. There are four Notch receptors (Notch1-4) and five ligands [Jagged1, Jagged2, δ-like ligand protein (DLL)1, DLL3 and DLL4]; therefore, it has been suggested that the different Notch receptors serve distinct roles in the same type of tissue. To determine whether this is the case, the present study measured the expression of all Notch receptors and their ligands in PDAC tissue samples and cells. Immunohistochemistry was performed to measure the expression of Notch receptors and their ligands in paraffin-embedded PDAC tissue samples. Immunofluorescence was used to detect the expression of Notch receptors in the pancreatic cancer cell lines human pancreatic adenocarcinoma (HPAC) and PANC-1. In addition, levels of Notch receptors and ligands in HPAC and PANC-1 cells were analyzed by western blot analysis. The results revealed that levels of Notch1 and Notch3 were increased in PDAC tissues, whereas levels of Notch2 and Notch3 were not. The expression of Notch receptors in the pancreatic cancer cell lines HPAC and PANC-1 was consistent with their expression in PDAC tissues. Additionally, levels of the ligands DLL1, DLL3 and DLL4 were increased in HPAC and PANC-1 cells, as well as PDAC tissue samples. However, the expression of Jagged1 and 2 remained low. These results indicate that Notch1, Notch3, DLL1, DLL3 and DLL4 are upregulated in PDAC, a positive correlation was observed between the expression of Notch1 and Notch3, and between Notch1 and the ligands DLL1, DLL3 and DLL4. whereas Notch2, Notch4, Jagged1 and Jagged2 are not. The interaction of Notch1 and Notch3 with Notch ligands DLL1, DLL3 and DLL4 may be important in maintaining the tumor phenotype of pancreatic cancer.

The function of Notch1 intracellular domain in the differentiation of gastric cancer

Due to the complex function of the Notch signal pathway in gastric cancer (GC), the association between Notch homolog 1 (Notch1) intracellular domain (NICD) and differentiation of GC remains unknown. The present study aimed to investigate the potential association between NICD and GC differentiation, and demonstrated that poorly differentiated GC expressed increased NICD levels compared with well differentiated GC. A γ-secretase inhibitor inhibited the growth of AGS cells through downregulating NICD level. Additional data suggested that a COX-2 inhibitor caused a marked reduction of NICD level in comparison with a control group treated with dimethyl sulfoxide. Combined administration of γ-secretase and COX-2 inhibitor produced a marked inhibition of growth in AGS cells, which suggests that patients with poorly differentiated GC may benefit from the blockage of NICD, which potentially serves a role in GC differentiation.

Expression of the Transcription Factor HEY1 in Glioblastoma: A Preliminary Clinical Study

Aims and background

The hairy/enhancer of split (E(spl))-related family of transcription factors (HES and HEY) are established targets of the notch signaling pathway, which has been implicated in different developmental processes, tumor formation and the self-renewal of neural stem cells. We determined the expression of HEY1 in human malignant gliomas to investigate whether its expression might be related to prognosis.

Methods

The expression of HEY1 was studied by in situ hybridization on 62 cases of glioblastoma. Patients were treated with surgery followed by chemotherapy and radiotherapy. We considered as end points of the study the overall survival time and progression-free interval. Correlations between HEY1 expression and tumor grade/patient overall survival and free interval before recurrence were analyzed using univariate analysis.

Results

Based on the in situ hybridization results, HEY1 expression rate was reported as negative staining in 13 cases (20.6%), as weak staining in 11 cases (17.3%), as moderate staining in 21 cases (33.3%), and as strong staining in 17 cases. We considered in the analysis the cumulative expression of HEY1 at in situ hybridization (Hey Index) as negative in 13 cases and positive in 49 cases (77.78%). The overall survival (P = 0.002) and the free-interval (P = 0.012) were significantly longer in patients who were negative for HEY1 expression.

Conclusions

Our data suggest that expression of HEY1 might be used as a marker to distinguish glioblastoma patients with a relatively good prognosis from those at high-risk, and that, in the future, HEY1 might represent a therapeutic target.

NOTCH signalinio kelio ir ginekologinių piktybinių navikų sąsaja

Įvadas. Organizmo ląstelėse vykstančius procesus kontroliuoja įvairūs signaliniai keliai. Vienas iš jų yra NOTCH signalinis kelias. Nustatyta, kad dalinis NOTCH funkcijos praradimas arba nenormalus NOTCH signalo aktyvinimas susijęs su įvairiais žmogaus vystymosi sutrikimais ir ligomis.

Medžiaga ir metodika. Pagrindinis informacijos šaltinis ieškant duomenų – PubMed duomenų bazė.

Rezultatai. Straipsnyje nagrinėjama onkologinių ligų bei NOTCH signalinio kelio dalyvių sąsaja. NOTCH signalas, vystantis vėžiui, gali veikti dvejopai: kaip onkogenas ir kaip naviko augimo slopiklis. Tikslus tokio poveikio mechanizmas dar nėra žinomas. NOTCH signalinio kelio tyrimai svarbūs siekiant atrasti naujus vėžio gydymo būdus, farmakologiniais ir genetiniais metodais valdant NOTCH signalinį kelią. Šioje apžvalgoje daugiausia dėmesio skiriama ginekologiniams piktybiniams navikams, ypač gimdos kūno vėžiui.

Išvados. Pastarųjų metų mokslinių tyrimų duomenys rodo, kad NOTCH signalinis kelias yra neabejotinai svarbus formuojantis gimdos kūno vėžiui, todėl jo komponentai gali būti potencialūs prognoziniai biožymenys ir molekuliniai terapiniai taikiniai. Siekiant patikslinti NOTCH signalinio kelio dalyvių reikšmę bei jų sąveiką su kitų signalinių kelių dalyviais, kurie taip pat gali būti svarbūs formuojantis ir progresuojant gimdos kūno vėžiui, reikalingi tolesni šios srities moksliniai tyrimai.

Notch signaling plays a crucial role in cancer stem-like cells maintaining stemness and mediating chemotaxis in renal cell carcinoma

Background

Cancer stem cells (CSCs) are correlated with the initiation, chemoresistance and relapse of tumors. Notch pathway has been reported to function in CSCs maintenance, but whether it is involved in renal cell carcinoma (RCC) CSCs maintaining stemness remain unclear. This study aims to explore the effect of Notch pathway on stemness of CSCs in RCC and the underlying mechanisms.

Methods

The CD133⁺/CD24⁺ cells were isolated from RCC ACHN and Caki-1 cell line using Magnetic-activated cell sorting and identified by Flow cytometry analysis. RT-PCR and immunoblot analyses were used for determining the stemness maker expression. The effect of Notch pathway on function of CSCs was assessed by self-renewal ability, chemosensitivity, invasive and migratory ability tumorigenicity in vivo using soft agar colony formation assay, sphere-forming assay, MTT assay, Transwell assay.

Results

Here, we found that the sorted CD133⁺/CD24⁺cells possessed elevated stemness maker CTR2, BCL-2, MDR1, OCT-4, KLF4, compared with parental cells, as well as enhanced self-renewal ability, stronger resistance to cisplatin and sorafenib, increased invasion and migration, and higher tumorigenesis in vivo, suggesting the CD133⁺/CD24⁺ cells have the stem-like characteristics of CSCs and thus identified as RCC CSCs. Then the enhanced notch1, notch2, Jagged1, Jagged2, DLL1 and DLL4 expression were detected in RCC CSCs and blockage of Notch1 or notch2 using pharmacological inhibitor MRK-003 or its endogenous inhibitor Numb resulted in loss of its stemness features: self-renewal, chemoresistance, invasive and migratory potential, and tumorigenesis in vivo. Moreover, it is confirmed that overexpression of notch1 up-regulated CXCR4 inRCC CSCs and augmented SDF-1-induced chemotaxis in RCC CSCs in vitro, which could be rescued when treatment of CXCR4 inhibitor, suggesting that notch signaling promotes the chemotaxis of RCC CSCs by SDF-1/CXCR4 axis.

Conclusions

Our results provide a new mechanism of RCC CSCs maintaining stemness via notch pathway as well as a potential therapeutic target in human RCC.

Notch Pathway Is Activated via Genetic and Epigenetic Alterations and Is a Therapeutic Target in Clear Cell Renal Cancer

Clear cell renal cell carcinoma (CCRCC) is an incurable malignancy in advanced stages and needs newer therapeutic targets. Transcriptomic analysis of CCRCCs and matched microdissected renal tubular controls revealed overexpression of NOTCH ligands and receptors in tumor tissues. Examination of the TCGA RNA-seq data set also revealed widespread activation of NOTCH pathway in a large cohort of CCRCC samples. Samples with NOTCH pathway activation were also clinically distinct and were associated with better overall survival. Parallel DNA methylation and copy number analysis demonstrated that both genetic and epigenetic alterations led to NOTCH pathway activation in CCRCC. NOTCH ligand JAGGED1 was overexpressed and associated with loss of CpG methylation of H3K4me1-associated enhancer regions. JAGGED2 was also overexpressed and associated with gene amplification in distinct CCRCC samples. Transgenic expression of intracellular NOTCH1 in mice with tubule-specific deletion of VHL led to dysplastic hyperproliferation of tubular epithelial cells, confirming the procarcinogenic role of NOTCH in vivo Alteration of cell cycle pathways was seen in murine renal tubular cells with NOTCH overexpression, and molecular similarity to human tumors was observed, demonstrating that human CCRCC recapitulates features and gene expression changes observed in mice with transgenic overexpression of the Notch intracellular domain. Treatment with the γ-secretase inhibitor LY3039478 led to inhibition of CCRCC cells in vitro and in vivo In summary, these data reveal the mechanistic basis of NOTCH pathway activation in CCRCC and demonstrate this pathway to a potential therapeutic target.

Targeting Stem Cells in Brain Tumors

Stem cells are commonly defined as undifferentiated cells capable of self-renewing and giving rise to a large number of differentiated progeny. It is becoming increasingly apparent that there exist cancer stem cells (CSCs) from which the cells of any given malignancy arise, whereby only a few cells out of a population of cancer cells are able to initiate tumor formation. These CSCs, like their normal counterparts, are characterized by self-renewal and the ability to “differentiate” into all of the cell types in the original tumor. Current chemotherapeutic strategies involve using non-specific cytotoxic agents that target rapidly cycling cells. Although this may reduce disease burden in many cases, these therapies may miss the rare, self-renewing population that truly gives rise to the malignancy (the CSC).

This review will focus on the recent discovery of stem cell-like cells in human brain tumors, putative “brain cancer stem cells,” which exhibit the properties of self-renewal and the ability to recapitulate the original tumor heterogeneity. Dissecting the molecular mechanisms that underlie the ability of these cells to self-renew and maintain quiescence may allow the development of novel therapeutic strategies that will allow for more efficacious and less toxic therapies for these devastating malignancies.

Pancreatic Cancer from Molecular Pathways to Treatment Opinion

Pancreatic cancer is considered one of the most lethal malignances. It has been observed that the five year survival rate is less than 5%. Early diagnosis, understanding the risk factors and investigation of the molecular pathways with targeted therapy are the keys for efficient treatment. Moreover; there are several local treatments for patients with unresectable pancreatic cancer. There are several combined therapies with chemotherapy and radiotherapy, however; a local therapy approach for many patients with poor performance status are in need. For those patients with good performance status new polychemotherapy regimens are used with success and increased survival improvement. Polychemotherapy has been observed to increase the rate of radical resections in some cases. Second line therapy is used for patients with good performance status and metastatic disease. Oxaliplatin-based regimens are mostly used, however; there are several other drugs that are being developed. Unfortunately, targeted therapy has not presented the expected efficiency. Moreover; immunotherapy; another treatment approach for several cancers types has again failed to present positive results for pancreatic cancer. In the current mini review, we will present information from the diagnosis to molecular pathways and targeted treatment.

NUMB inactivation confers resistance to imatinib in chronic myeloid leukemia cells

Chronic myeloid leukemia (CML) progresses from a chronic to a blastic phase, where the leukemic cells are proliferative and undifferentiated. The CML is nowadays successfully treated with BCR-ABL kinase inhibitors as imatinib and its derivatives. NUMB is an evolutionary well-conserved protein initially described as a functional antagonist of NOTCH function. NUMB is an endocytic protein associated with receptor internalization, involved in multiple cellular functions. It has been reported that MSI2 protein, a NUMB inhibitor, is upregulated in CML blast crisis, whereas NUMB itself is downregulated. This suggest that NUMB plays a role in the malignant progression of CML. Here we have generated K562 cells (derived from CML in blast crisis) constitutively expressing a dominant negative form of NUMB (dnNUMB). We show that dnNUMB expression confers a high proliferative phenotype to the cells. Importantly, dnNUMB triggers a partial resistance to imatinib in these cells, antagonizing the apoptosis mediated by the drug. Interestingly, imatinib resistance is not linked to p53 status or NOTCH signaling, as K562 lack p53 and imatinib resistance is reproduced in the presence of NOTCH inhibitors. Taken together, our data support the hypothesis that NUMB activation could be a new therapeutic target in CML.

Pancreatic cancer from bench to bedside: molecular pathways and treatment options

In the last forty years the pancreatic cancer treatment has made advances, however; still novel drugs are needed. It is known that the five year survival rate remains around 5%. The best treatment option still remains surgery, if patients are diagnosed early. In the last decade the biology of pancreatic cancer has been vastly explored and novel agents such as; tyrosine kinase agents, or vaccines have been added as a treatment perspective. The big challenge is now to translate this knowledge in better outcomes for patients. In this current review we will present information from pancreatic cancer diagnosis to molecular pathways and treatment options; current and future.

The mTOR pathway in obesity driven gastrointestinal cancers: Potential targets and clinical trials

The mechanistic target of rapamycin (mTOR) is a crucial point of convergence between growth factor signalling, metabolism, nutrient status and cellular proliferation. The mTOR pathway is heavily implicated in the progression of many cancers and is emerging as an important driver of gastrointestinal (GI) malignancies. Due to its central role in adapting metabolism to environmental conditions, mTOR signalling is also believed to be critical in the development of obesity. Recent research has delineated that excessive nutrient intake can promote signalling through the mTOR pathway and possibly evoke changes to cellular metabolism that could accelerate obesity related cancers. Acting through its two effector complexes mTORC1 and mTORC2, mTOR dictates the transcription of genes important in glycolysis, lipogenesis, protein translation and synthesis and has recently been defined as a central mediator of the Warburg effect in cancer cells. Activation of the mTOR pathway is involved in both the pathogenesis of GI malignancies and development of resistance to conventional chemotherapy and radiotherapy. The use of mTOR inhibitors is a promising therapeutic option in many GI malignancies, with greatest clinical efficacy seen in combination regimens. Recent research has also provided insight into crosstalk between mTOR and other pathways which could potentially expand the list of therapeutic targets in the mTOR pathway. Here we review the available strategies for targeting the mTOR pathway in GI cancers. We discuss current clinical trials of both established and novel mTOR inhibitors, with particular focus on combinations of these drugs with conventional chemotherapy, radiotherapy and targeted therapies.

Notch1 downregulation combined with interleukin-24 inhibits invasion and migration of hepatocellular carcinoma cells

AIM: To confirm the anti-invasion and anti-migration effects of down-regulation of Notch1 combined with interleukin (IL)-24 in hepatocellular carcinoma (HCC) cells.

METHODS: γ-secretase inhibitors (GSIs) were used to down-regulate Notch1. HepG2 and SMMC7721 cells were seeded in 96-well plates and treated with GSI-I or/and IL-24 for 48 h. Cell viability was measured by MTT assay. The cellular and nuclear morphology was observed under a fluorescence microscope. To further verify the apoptotic phenotype, cell cultures were also analyzed by flow cytometry with Annexin V-FITC/propidium iodide staining. The expression of Notch1, SNAIL1, SNAIL2, E-cadherin, IL-24, XIAP and VEGF was detected by Western blot. The invasion and migration capacities of HCC cells were detected by wound healing assays. Notch1 and Snail were down-regulated by RNA interference, and the target proteins were analyzed by Western blot. To investigate the mechanism of apoptosis, we analyzed HepG2 cells treated with siNotch1 or siCON plus IL-24 or not for 48 h by caspase-3/7 activity luminescent assay.

RESULTS: GSI-I at a dose of 2.5 μmol/L for 24 h caused a reduction in cell viability of about 38% in HepG2 cells. The addition of 50 ng/mL IL-24 in combination with 1 or 2.5 μmol/L GSI-I reduced cell viability of about 30% and 15%, respectively. Treatment with IL-24 alone did not induce any cytotoxic effect. In SMMC7721 cells with the addition of IL-24 to GSI-I (2.5 μmol/L), the reduction of cell viability was only about 25%. Following GSI-I/IL-24 combined treatment for 6 h, the apoptotic rate of HepG2 cells was 47.2%, while no significant effect was observed in cells treated with the compounds employed separately. Decreased expression of Notch1 and its associated proteins SNAIL1 and SNAIL2 was detected in HepG2 cells. Increased E-cadherin protein expression was noted in the presence of IL-24 and GSI-I. Furthermore, the increased GSI-I and IL-24 in HepG2 cell was associated with downregulation of MMP-2, XIAP and VEGF. In the absence of treatment, HepG2 cells could migrate into the scratched space in 24 h. With IL-24 or GSI-I treatment, the wound was still open after 24 h. And the distance of the wound closure strongly correlated with the concentrations of IL-24 and GSI-I. Treatment of Notch-1 silenced HepG2 cells with 50 ng/mL IL-24 alone for 48 h induced cytotoxic effects very similar to those observed in non-silenced cells treated with GSI-I/IL-24 combination. Caspase-3/7 activity was increased in the presence of siNotch1 plus IL-24 treatment.

CONCLUSION: Down-regulation of Notch1 by GSI-I or siRNA combined with IL-24 can sensitize apoptosis and decrease the invasion and migration capabilities of HepG2 cells.

Novel strategies targeting cancer stem cells through phytochemicals and their analogs

Cancer stem cells (CSCs) are cells that exist within a tumor with a capacity of self-renewal and an ability to differentiate, giving rise to heterogeneous populations of cancer cells. These cells are increasingly being implicated in resistance to conventional therapeutics and have also been implicated in tumor recurrence. Several cellular signaling pathways including Notch, Wnt, phosphoinositide-3-kinase-Akt-mammalian target of rapamycin pathways, and known markers such as CD44, CD133, CD166, ALDH, etc. have been associated with CSCs. Here, we have reviewed our current understanding of self-renewal pathways and factors that help in the survival of CSCs with special emphasis on those that have been documented to be modulated by well characterized natural agents such as curcumin, sulforaphane, resveratrol, genistein, and epigallocatechin gallate. With the inclusion of a novel derivative of curcumin, CDF, we showcase how natural agents can be effectively modified to increase their efficacy, particularly against CSCs. We hope that this article will generate interest among researchers for further mechanistic and clinical studies exploiting the cancer preventive and therapeutic role of nutraceuticals by targeted elimination of CSCs.

Novel approaches in the management of pancreatic ductal adenocarcinoma: potential promises for the future

Despite a few breakthroughs in therapy for advanced disease in the recent years, pancreatic ductal adenocarcinoma continues to remain one of the most challenging human malignancies to treat. The overall prognosis for the majority of patients with pancreatic cancer is rather dismal, and therefore, more effective treatment options are being desperately sought. The practical goals of management are to improve the cure rates for patients with resectable disease, achieve a higher conversion rate of locally advanced tumor into potentially resectable disease, and finally, prolong the overall survival for those who develop metastatic disease. Our understanding of the complex genetic alterations, the implicated molecular pathways, and the role of desmoplastic stroma in pancreatic cancer tumorigenesis has increased several folds in the recent years. This has facilitated the development of novel therapeutic strategies against pancreatic cancer, some of which are currently under evaluation in ongoing preclinical and clinical studies. This review will summarize the existing treatment approaches for this devastating disease and also discuss the promising therapeutic approaches that are currently in different stages of clinical development.

Effects of JWA, XRCC1 and BRCA1 mRNA expression on molecular staging for personalized therapy in patients with advanced esophageal squamous cell carcinoma

BACKGROUND

DNA damage repair genes JWA, XRCC1 and BRCA1 were associated with clinical outcomes and could convert the response to the cisplatin-based therapy in some carcinomas. The synergistic effects of JWA, XRCC1 and BRCA1 mRNA expression on personalized therapy remain unknown in advanced esophageal squamous cell carcinoma (ESCC).

METHODS

We employed quantitative real-time polymerase chain reaction (qPCR) to determine the expression of JWA, XRCC1 and BRCA1 mRNA in paraffin-embedded specimen from 172 patients with advanced ESCC who underwent the first-line cisplatin-or docetaxel-based treatments.

RESULTS

High JWA or XRCC1mRNA expression was correlated with longer median overall survival (mOS) in all the patients (both P<0.001) or in subgroups with different regimens (all P<0.05), but not correlated with response rate (RR, all P>0.05). Multivariate analysis revealed that high JWA (HR 0.22; 95% CI 0.13-0.37; P<0.001) or XRCC1 (HR 0.36; 95% CI 0.21-0.63; P<0.001) mRNA expression emerged as the independent prognostic factors for ESCC patients in this cohort. But no significant difference in prognostic efficacy was found between JWA plus XRCC1 and JWA alone through ROC analysis. Further subgroup analysis showed cisplatin-based treatments could improve mOS of patients with low JWA expression (P<0.05), especially in those with low BRCA1 expression simultaneously (P<0.001); while in patients with high JWA expression, high BRCA1 mRNA expression was correlated with increased mOS in docetaxel-based treatments (P=0.044).

CONCLUSION

JWA, XRCC1and BRCA1 mRNA expression could be used as predictive markers in molecular staging for personalized therapy in patients with advanced ESCC who received first-line cisplatin- or docetaxel-based treatments.

DAPT suppresses the proliferation of human glioma cell line SHG-44

OBJECTIVE

To explore the suppressing effect of γ-secretase inhibitor DAPT on proliferation of human glioma cell line SHG-44 in vitro and its mechanism.

METHODS

The SHG-44 cell was treated by DAPT with different concentration. The proliferation of cells was detected by MTT assay; cell cycle and TSC of CD133(+) were determined by flow cytometry analysis technique; the key factor in Notch signaling pathway (Notch-1, Delta-1, Hes-1) was measured by reverse transcriptase-polymerase chain reaction and western blotting.

RESULTS

DAPT inhibited the growth and proliferation of SHG-44 cells significantly(P<0.05). And the inhibiting effect on SHG-44 cells produced by DAPT showed a dose-dependent manner. DAPT increased the rate of cells in G0/G1 phase of SHG-44 cells, while it decreased the rate of cells in S phase. TSC of CD133(+) was significantly reduced after DAPT treated SHG-44 cells. The expression of protein and mRNA of Notch-1, Delta-1 and Hes-1 were gradually downregulated with the increase of DAPT doses.

CONCLUSIONS

DAPT can downregulate these key factor in Notch signaling pathway, reduce the TSC of CD133+ and inhibit the proliferation of SHG-44 cells.

Evasion of anti-growth signaling: A key step in tumorigenesis and potential target for treatment and prophylaxis by natural compounds

The evasion of anti-growth signaling is an important characteristic of cancer cells. In order to continue to proliferate, cancer cells must somehow uncouple themselves from the many signals that exist to slow down cell growth. Here, we define the anti-growth signaling process, and review several important pathways involved in growth signaling: p53, phosphatase and tensin homolog (PTEN), retinoblastoma protein (Rb), Hippo, growth differentiation factor 15 (GDF15), AT-rich interactive domain 1A (ARID1A), Notch, insulin-like growth factor (IGF), and Krüppel-like factor 5 (KLF5) pathways. Aberrations in these processes in cancer cells involve mutations and thus the suppression of genes that prevent growth, as well as mutation and activation of genes involved in driving cell growth. Using these pathways as examples, we prioritize molecular targets that might be leveraged to promote anti-growth signaling in cancer cells. Interestingly, naturally occurring phytochemicals found in human diets (either singly or as mixtures) may promote anti-growth signaling, and do so without the potentially adverse effects associated with synthetic chemicals. We review examples of naturally occurring phytochemicals that may be applied to prevent cancer by antagonizing growth signaling, and propose one phytochemical for each pathway. These are: epigallocatechin-3-gallate (EGCG) for the Rb pathway, luteolin for p53, curcumin for PTEN, porphyrins for Hippo, genistein for GDF15, resveratrol for ARID1A, withaferin A for Notch and diguelin for the IGF1-receptor pathway. The coordination of anti-growth signaling and natural compound studies will provide insight into the future application of these compounds in the clinical setting.

Molecular biology of pancreatic ductal adenocarcinoma

PURPOSE OF REVIEW

Recent advances in sequencing technology have led to a deeper and more comprehensive understanding of the molecular biology of pancreatic ductal adenocarcinoma. This timely review seeks to summarize these recent advances which will provide a foundation for future studies in the field.

RECENT FINDINGS

Stereotypical genetic alterations have been identified and confirmed. However, additional alterations have highlighted the importance and complexity of a number of intracellular signaling pathways that present unique opportunities for therapeutic targeting.

SUMMARY

A genetic signature of pancreatic ductal adenocarcinoma has been identified. This recent and important work is currently in the process of being applied in many clinical applications from early diagnostics to customized therapeutic regimens for this disease. A fundamental understanding of these findings will thus be of utmost importance for future research in the field and in the clinical care of patients with this lethal disease.

Current and future systemic treatment options in metastatic pancreatic cancer

Although pancreatic adenocarcinoma is the fourth leading cause of cancer death, only modest improvement has been observed in the past two decades, single agent gemcitabine has been the only standard treatment in patients with advanced disease. Recently newer agents such as nab-paclitaxel, nimotuzumab and regimens such as FOLFIRINOX have been shown to have promising activity being superior to gemcitabine as a single agent. With better understanding of tumour biology coupled with the improvements in targeted and immunotherapies, there is increasing expectation for better response rates and extended survival in pancreatic cancer.

Pancreatic cancer: advances in treatment

Pancreatic cancer is a leading cause of cancer mortality and the incidence of this disease is expected to continue increasing. While patients with pancreatic cancer have traditionally faced a dismal prognosis, over the past several years various advances in diagnosis and treatment have begun to positively impact this disease. Identification of effective combinations of existing chemotherapeutic agents, such as the FOLFIRINOX and the gemcitabine + nab-paclitaxel regimen, has improved survival for selected patients although concerns regarding their toxicity profiles remain. A better understanding of pancreatic carcinogenesis has identified several pre-malignant precursor lesions, such as pancreatic intraepithelial neoplasias, intraductal papillary mucinous neoplasms, and cystic neoplasms. Imaging technology has also evolved dramatically so as to allow early detection of these lesions and thereby facilitate earlier management. Surgery remains a cornerstone of treatment for patients with resectable pancreatic tumors, and advances in surgical technique have allowed patients to undergo resection with decreasing perioperative morbidity and mortality. Surgery has also become feasible in selected patients with borderline resectable tumors as a result of neoadjuvant therapy. Furthermore, pancreatectomy involving vascular reconstruction and pancreatectomy with minimally invasive techniques have demonstrated safety without significantly compromising oncologic outcomes. Lastly, a deeper understanding of molecular aberrations contributing to the development of pancreatic cancer shows promise for future development of more targeted and safe therapeutic agents.

Livistona chinensis seeds inhibit hepatocellular carcinoma angiogenesis in vivo via suppression of the Notch pathway

Livistona chinensis seeds have been used for centuries to clinically treat various types of cancer. Our published data suggest that Livistona chinensis seeds are able to inhibit hepatocellular carcinoma (HCC) growth in vitro and in vivo via promotion of mitochondrial-dependent apoptosis. To further elucidate the molecular mechanisms of its antitumor activity, in the present study, we used an HCC xenograft mouse model to evaluate the effect of an ethanol extract of Livistona chinensis seeds (EELC) on tumor angiogenesis and on the activation of the Notch pathway. Intratumoral microvessel density (MVD) in HCC xenograft mouse tumors was evaluated via immunohistochemical (IHC) staining for CD31. The mRNA and protein expression of vascular endothelial growth factor A (VEGF-A), VEGFR-2, Notch, Dll4 and Jagged1 was evaluated using RT-PCR and IHC, respectively. We found that EELC profoundly reduced MVD in the HCC mouse tumors, demonstrating the in vivo inhibitory effect of EELC on tumor angiogenesis. In addition, EELC treatment reduced the expression of VEGF-A and VEGFR-2 in tumor tissues. Furthermore, EELC treatment inhibited the expression of Notch, Dll4 and Jagged1. Our findings suggest that Livistona chinensis seeds inhibit tumor angiogenesis through suppression of the Notch pathway.

Genetic and molecular alterations in pancreatic cancer: implications for personalized medicine

Recent advances in human genomics and biotechnologies have profound impacts on medical research and clinical practice. Individual genomic information, including DNA sequences and gene expression profiles, can be used for prediction, prevention, diagnosis, and treatment for many complex diseases. Personalized medicine attempts to tailor medical care to individual patients by incorporating their genomic information. In a case of pancreatic cancer, the fourth leading cause of cancer death in the United States, alteration in many genes as well as molecular profiles in blood, pancreas tissue, and pancreas juice has recently been discovered to be closely associated with tumorigenesis or prognosis of the cancer. This review aims to summarize recent advances of important genes, proteins, and microRNAs that play a critical role in the pathogenesis of pancreatic cancer, and to provide implications for personalized medicine in pancreatic cancer.

Context dependent reversion of tumor phenotype by connexin-43 expression in MDA-MB231 cells and MCF-7 cells: role of β-catenin/connexin43 association

Connexins (Cx), gap junction (GJ) proteins, are regarded as tumor suppressors, and Cx43 expression is often down regulated in breast tumors. We assessed the effect of Cx43 over-expression in 2D and 3D cultures of two breast adenocarcinoma cell lines: MCF-7 and MDA-MB-231. While Cx43 over-expression decreased proliferation of 2D and 3D cultures of MCF-7 by 56% and 80% respectively, MDA-MB-231 growth was not altered in 2D cultures, but exhibited 35% reduction in 3D cultures. C-terminus truncated Cx43 did not alter proliferation. Untransfected MCF-7 cells formed spherical aggregates in 3D cultures, and MDA-MB-231 cells formed stellar aggregates. However, MCF-7 cells over-expressing Cx43 formed smaller sized clusters and Cx43 expressing MDA-MB-231 cells lost their stellar morphology. Extravasation ability of both MCF-7 and MDA-MB-231 cells was reduced by 60% and 30% respectively. On the other hand, silencing Cx43 in MCF10A cells, nonneoplastic human mammary cell line, increased proliferation in both 2D and 3D cultures, and disrupted acinar morphology. Although Cx43 over-expression did not affect total levels of β-catenin, α-catenin and ZO-2, it decreased nuclear levels of β-catenin in 2D and 3D cultures of MCF-7 cells, and in 3D cultures of MDA-MB-231 cells. Cx43 associated at the membrane with α-catenin, β-catenin and ZO-2 in 2D and 3D cultures of MCF-7 cells, and only in 3D conditions in MDA-MB-231 cells. This study suggests that Cx43 exerts tumor suppressive effects in a context-dependent manner where GJ assembly with α-catenin, β-catenin and ZO-2 may be implicated in reducing growth rate, invasiveness, and, malignant phenotype of 2D and 3D cultures of MCF-7 cells, and 3D cultures of MDA-MB-231 cells, by sequestering β-catenin away from nucleus.

Carcinogenesis of pancreatic adenocarcinoma: precursor lesions

Pancreatic adenocarcinoma displays a variety of molecular changes that evolve exponentially with time and lead cancer cells not only to survive, but also to invade the surrounding tissues and metastasise to distant sites. These changes include: genetic alterations in oncogenes and cancer suppressor genes; changes in the cell cycle and pathways leading to apoptosis; and also changes in epithelial to mesenchymal transition. The most common alterations involve the epidermal growth factor receptor (EGFR) gene, the HER2 gene, and the K-ras gene. In particular, the loss of function of tumor-suppressor genes has been documented in this tumor, especially in CDKN2a, p53, DPC4 and BRCA2 genes. However, other molecular events involved in pancreatic adenocarcinoma pathogenesis contribute to its development and maintenance, specifically epigenetic events. In fact, key tumor suppressors that are well established to play a role in pancreatic adenocarcinoma may be altered through hypermethylation, and oncogenes can be upregulated secondary to permissive histone modifications. Indeed, factors involved in tumor invasiveness can be aberrantly expressed through dysregulated microRNAs. This review summarizes current knowledge of pancreatic carcinogenesis from its initiation within a normal cell until the time that it has disseminated to distant organs. In this scenario, highlighting these molecular alterations could provide new clinical tools for early diagnosis and new effective therapies for this malignancy.

Role of LRF/Pokemon in lineage fate decisions

In the human genome, 43 different genes are found that encode proteins belonging to the family of the POK (poxvirus and zinc finger and Krüppel)/ZBTB (zinc finger and broad complex, tramtrack, and bric à brac) factors. Generally considered transcriptional repressors, several of these genes play fundamental roles in cell lineage fate decision in various tissues, programming specific tasks throughout the life of the organism. Here, we focus on functions of leukemia/lymphoma-related factor/POK erythroid myeloid ontogenic factor, which is probably one of the most exciting and yet enigmatic members of the POK/ZBTB family.

Notch1 signaling contributes to the oncogenic effect of HBx on human hepatic cells

Hepatocellular carcinoma (HCC) is a malignant tumor and hepatitis B virus X protein (HBx) plays a crucial role in its pathogenesis. The Notch1 signaling pathway is involved in various malignant tumors including liver cancers and down-regulation of Notch-1 may exert anti-tumor effects. Here, we demonstrate that inhibition of Notch1 by plasmid-based shRNA suppresses growth of human hepatic cells transfected with HBx through G0/G1 cell cycle arrest and apoptosis inhibition, possibly linked to the promoted expression of cyclin-dependent kinase inhibitor, P16, and decreased expression of apoptosis inhibitor, Bcl-2. The anti-proliferative and pro-apoptotic effects of Notch1 shRNA in HBx-transformed L02 cell may be partly mediated by down-regulation of nuclear factor-kappaB (NF-κB) binding activities, demonstrating possible cross-talk between Notch-1 and NF-κB signaling pathways. The oncogene HBx may therefore induce malignant transformation of human hepatic cells via Notch1 pathway, indicating that Notch1 plays a crucial role in HBx-related liver cancer and could be an effective therapeutic target for HCC.

The role of cancer stem cells in breast cancer initiation and progression: potential cancer stem cell-directed therapies

Recent studies have identified a small population of highly tumorigenic cells with stem cell properties in human breast and other solid tumors that are considered to be the source of tumor initiation and maintenance; these cells are referred to as cancer stem cells (CSCs). Preclinical data suggest that current breast cancer treatment strategies lead to CSC enrichment, contributing to chemotherapy and radiotherapy resistance, although a strong correlation with clinical parameters and prognosis is yet to be established. Importantly, overcoming treatment failure by effective targeting of CSCs may be an appealing approach, potentially leading to improved clinical outcomes for patients with breast cancer. Several preclinical studies provide promising results that support this hypothesis. The purpose of this review is to summarize the role of CSCs in breast cancer recurrence and resistance and to discuss current attempts of CSC targeting.

Fibulin-3 promotes glioma growth and resistance through a novel paracrine regulation of Notch signaling

Malignant gliomas are highly invasive and chemoresistant brain tumors with extremely poor prognosis. Targeting of the soluble factors that trigger invasion and resistance, therefore, could have a significant impact against the infiltrative glioma cells that are a major source of recurrence. Fibulin-3 is a matrix protein that is absent in normal brain but upregulated in gliomas and promotes tumor invasion by unknown mechanisms. Here, we show that fibulin-3 is a novel soluble activator of Notch signaling that antagonizes DLL3, an autocrine inhibitor or Notch, and promotes tumor cell survival and invasion in a Notch-dependent manner. Using a strategy for inducible knockdown, we found that controlled downregulation of fibulin-3 reduced Notch signaling and led to increased apoptosis, reduced self-renewal of glioblastoma-initiating cells, and impaired growth and dispersion of intracranial tumors. In addition, fibulin-3 expression correlated with expression levels of Notch-dependent genes and was a marker of Notch activation in patient-derived glioma samples. These findings underscore a major role for the tumor extracellular matrix in regulating glioma invasion and resistance to apoptosis via activation of the key Notch pathway. More importantly, this work describes a noncanonical, soluble activator of Notch in a cancer model and shows how Notch signaling can be reduced by targeting tumor-specific accessible molecules in the tumor microenvironment.

Notch1-mediated tumor suppression in cervical cancer with the involvement of SST signaling and its application in enhanced SSTR-targeted therapeutics

The role of Notch signaling in cervical cancer is seemingly controversial. To confirm the function of Notch signaling in this type of cancer, we established a stable Notch1-activated cervical cancer HeLa cell line. We found that Notch1 activation resulted in apoptosis, cell cycle arrest, and tumor suppression. At the molecular level, we found that a variety of genes associated with cyclic AMP, G protein-coupled receptor, and cancer signaling pathways contributed to Notch1-mediated tumor suppression. We observed that the expression of somatostatin (SST) was dramatically induced by Notch1 signaling activation, which was accompanied by enhanced expression of the cognate SST receptor subtype 1 (SSTR1) and SSTR2. Certain genes, such as tumor protein 63 (TP63, p63), were upregulated, whereas others, such as B-cell lymphoma 2 (BCL-2), Myc, Akt, and STAT3, were downregulated. Subsequently, knockdown of Notch1-induced SST reversed Notch1-induced decrease of BCL-2 and increase of p63, indicating that Notch1-induced tumor suppression may be partly through upregulating SST signaling. Our findings support a possible crosstalk between Notch signaling and SST signaling. Moreover, Notch-induced SSTR activation could enhance SSTR-targeted cancer chemotherapy. Valproic acid (VPA), a histone deacetylase inhibitor, suppressed cell growth and upregulated the expression of Notch1 and SSTR2. A combination therapy with VPA and the SSTR2-targeting cytotoxic conjugate CPT-SST strongly led to greater suppression, as compared to each alone. Our findings thus provide us with a promising clinical opportunity for enhanced cancer therapy using combinations of Notch1-activating agents and SSTR2-targeting agents.

Hepatitis B virus X protein promotes the growth of hepatocellular carcinoma by modulation of the Notch signaling pathway

Hepatitis B virus X protein (HBx) plays a crucial role in the development of hepatocellular carcinoma (HCC), however, little is known about the mechanism. Here, we investigated the relationship between HBx and Notch signaling in HepG2 cells after they were transfected with the HBx gene. It was found that HBx upregulated the expression of Notch-1, Jagged-1 and Hes-1 at the transcriptional level by binding to the Notch-1 intracellular domain, which is congruent with the observations of enhanced malignant biological activities of HBx-transfected HepG2 cells compared with normal HepG2 cells. However, while Notch signaling was blocked, the HBx-induced abnormalities were partially reversed. These findings suggest that HBx may promote the progression of HCC via the activated Notch pathway.

The Stem Cell Discovery Engine: an integrated repository and analysis system for cancer stem cell comparisons

Mounting evidence suggests that malignant tumors are initiated and maintained by a subpopulation of cancerous cells with biological properties similar to those of normal stem cells. However, descriptions of stem-like gene and pathway signatures in cancers are inconsistent across experimental systems. Driven by a need to improve our understanding of molecular processes that are common and unique across cancer stem cells (CSCs), we have developed the Stem Cell Discovery Engine (SCDE)-an online database of curated CSC experiments coupled to the Galaxy analytical framework. The SCDE allows users to consistently describe, share and compare CSC data at the gene and pathway level. Our initial focus has been on carefully curating tissue and cancer stem cell-related experiments from blood, intestine and brain to create a high quality resource containing 53 public studies and 1098 assays. The experimental information is captured and stored in the multi-omics Investigation/Study/Assay (ISA-Tab) format and can be queried in the data repository. A linked Galaxy framework provides a comprehensive, flexible environment populated with novel tools for gene list comparisons against molecular signatures in GeneSigDB and MSigDB, curated experiments in the SCDE and pathways in WikiPathways. The SCDE is available at http://discovery.hsci.harvard.edu.

Notch signalling is off and is uncoupled from HES1 expression in Ewing's sarcoma

Notch can act as an oncogene or as a tumour suppressor and thus can either promote or inhibit tumour cell growth. To establish Notch status in Ewing's sarcoma family of tumours (ESFT), we investigated the Notch pathway by gene expression profiling meta-analysis or immunohistochemistry in samples obtained from 96 and 24 ESFT patients, respectively. We found that although Notch receptors were highly expressed, Notch did not appear to be active, as evidenced by the absence of Notch receptors in cell nuclei. In contrast, we show that Notch receptors known to be active in colon adenocarcinoma, hepatocarcinoma, and pancreatic carcinoma stain cell nuclei in these tumours. High expression of the Notch effector HES1 transcription factor, usually used as a surrogate marker for active Notch, was also restricted to outside of the nucleus in the majority of ESFT, and analysis of HES1 gene targets indicated HES1 to be transcriptionally inactive. Neither forced activation nor pharmacological or genetic blocking of Notch affected HES1 expression in ESFT cells, indicating HES1 expression to be uncoupled from the Notch pathway. Additional functional studies in ESFT cell lines confirmed Notch to be switched off. Finally, unlike experiments in which HES1 expression was modulated, experimental activation of Notch in ESFT cell lines via several means blocked cell proliferation and reduced their clonogenic potential in soft agar. These indicate that HES1 is uncoupled from Notch in ESFT, that EWS-FLI1-mediated inhibition of Notch contributes to ESFT aggressive cell growth, and support a role for Notch in ESFT tumour suppression, at least partly through the Notch effector HEY1.