Ligand-dependent Notch signaling is involved in tumor initiation and tumor maintenance in pancreatic cancer

DLL3 Is a Prognostic and Potentially Predictive Biomarker for Immunotherapy Linked to PD/PD-L Axis and NOTCH1 in Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive neoplasm with very poor patient survival outcomes despite available treatments. There is an urgent need for new potential treatment options and novel biomarkers for these patients. Delta-like canonical Notch ligand 3 (DLL3) interacts with the Notch receptor and causes inhibition of Notch signaling, which confers a survival advantage to PDAC cells. Thus, DLL3 expression could affect cell survival, and its inhibition could increase a patient's survival. To test this hypothesis, a survival analysis was conducted using the progression-free and overall survival from two independent datasets of PDAC patients, with one using mRNA z-score levels and the other using the Hscore protein expression level; both were carried out using a log-rank test and plotted using Kaplan-Meier curves. DLL3 at the mRNA expression level showed an association between high mRNA expression and both a longer progression-free survival (PFS) and overall survival (OS) of patients. Then, we designed a retrospective study with resected PDAC samples. Our primary objective with this dataset was to assess the relationship between PFS and OS and DLL3 protein expression. The secondary assessment was to provide a rationale for the use of anti-DLL3-based treatments in combination with immunotherapy that is supported by the link between DLL3 and other factors that are involved in immune checkpoints. The survival analyses revealed a protective effect of high DLL3 protein expression levels in both PFS and OS. Interestingly, high DLL3 protein expression levels were significantly correlated with PD-L1/2 and negatively correlated with NOTCH1. Therefore, DLL3 could be considered a biomarker for better prognosis in resectable PDAC patients as well as a therapeutic biomarker for immunotherapy response. These facts set a rationale for testing anti-DLL3-based treatments either alone or combined with immunotherapy or other NOTCH1 inhibitors.

Krüppel-like factor 10 modulates stem cell phenotypes of pancreatic adenocarcinoma by transcriptionally regulating notch receptors

BACKGROUND

Pancreatic adenocarcinoma (PDAC) is well known for its rapid distant metastasis and local destructive behavior. Loss of Krüppel-like factor 10 (KLF10) contributes to distant migration of PDAC. The role of KLF10 in modulating tumorigenesis and stem cell phenotypes of PDAC is unclear.

METHODS

Additional depletion of KLF10 in KC (LSL: Kras^G12D; Pdx1-Cre) mice, a spontaneous murine PDAC model, was established to evaluate tumorigenesis. Tumor specimens of PDAC patients were immune-stained of KLF10 to correlate with local recurrence after curative resection. Conditional overexpressing KLF10 in MiaPaCa and stably depleting KLF10 in Panc-1 (Panc-1-pLKO-shKLF10) cells were established for evaluating sphere formation, stem cell markers expression and tumor growth. The signal pathways modulated by KLF10 for PDAC stem cell phenotypes were disclosed by microarray analysis and validated by western blot, qRT-PCR, luciferase reporter assay. Candidate targets to reverse PDAC tumor growth were demonstrated in murine model.

RESULTS

KLF10, deficient in two-thirds of 105 patients with resected pancreatic PDAC, was associated with rapid local recurrence and large tumor size. Additional KLF10 depletion in KC mice accelerated progression from pancreatic intraepithelial neoplasia to PDAC. Increased sphere formation, expression of stem cell markers, and tumor growth were observed in Panc-1-pLKO-shKLF10 compared with vector control. Genetically or pharmacologically overexpression of KLF10 reversed the stem cell phenotypes induced by KLF10 depletion. Ingenuity pathway analysis and gene set enrichment analysis showed that Notch signaling molecules, including Notch receptors 3 and 4, were over-expressed in Panc-1-pLKO-shKLF10. KLF10 transcriptionally suppressed Notch-3 and -4 by competing with E74-like ETS transcription factor 3, a positive regulator, for promoter binding. Downregulation of Notch signaling, either genetically or pharmacologically, ameliorated the stem cell phenotypes of Panc-1-pLKO-shKLF10. The combination of metformin, which upregulated KLF10 expression via phosphorylating AMPK, and evodiamine, a non-toxic Notch-3 methylation stimulator, delayed tumor growth of PDAC with KLF10 deficiency in mice without prominent toxicity.

CONCLUSIONS

These results demonstrated a novel signaling pathway by which KLF10 modulates stem cell phenotypes in PDAC through transcriptionally regulating Notch signaling pathway. The elevation of KLF10 and suppression of Notch signaling may jointly reduce PDAC tumorigenesis and malignant progression.

The Intricate Notch Signaling Dynamics in Therapeutic Realms of Cancer

The Notch pathway is remarkably simple without the interventions of secondary messengers. It possesses a unique receptor-ligand interaction that imparts signaling upon cleavage of the receptor followed by the nuclear localization of its cleaved intracellular domain. It is found that the transcriptional regulator of the Notch pathway lies at the intersection of multiple signaling pathways that enhance the aggressiveness of cancer. The preclinical and clinical evidence supports the pro-oncogenic function of Notch signaling in various tumor subtypes. Owing to its oncogenic role, the Notch signaling pathway assists in enhanced tumorigenesis by facilitating angiogenesis, drug resistance, epithelial to mesenchymal transition, etc., which is also attributed to the poor outcome in patients. Therefore, it is extremely vital to discover a suitable inhibitor to downregulate the signal-transducing ability of Notch. The Notch inhibitory agents, such as receptor decoys, protease (ADAM and γ-secretase) inhibitors, and monoclonal/bispecific antibodies, are being investigated as candidate therapeutic agents. Studies conducted by our group exemplify the promising results in ablating tumorigenic aggressiveness by inhibiting the constituents of the Notch pathway. This review deals with the detailed mechanism of the Notch pathways and their implications in various malignancies. It also bestows us with the recent therapeutic advances concerning Notch signaling in the context of monotherapy and combination therapy.

Jaggeds/Notches promote endothelial-mesenchymal transition-mediated pulmonary arterial hypertension via upregulation of the expression of GATAs

This study tested the hypothesis that Jagged2/Notches promoted the endothelial-mesenchymal transition (endMT)-mediated pulmonary arterial hypertension (PAH) (i.e. induction by monocrotaline [MCT]/63 mg/kg/subcutaneous injection) through increasing the expression of GATA-binding factors which were inhibited by propylthiouracil (PTU) (i.e. 0.1% in water for daily drinking since Day 5 after PAH induction) in rodent. As compared with the control (i.e. HUVECs), the protein expressions of GATAs (3/4/6) and endMT markers (Snail/Zeb1/N-cadherin/vimentin/fibronectin/α-SMA/p-Smad2) were significantly reduced, whereas the endothelial-phenotype markers (CD31/E-cadherin) were significantly increased in silenced JAG2 gene or in silenced GATA3 gene of HUVECs (all p < 0.001). As compared with the control, the protein expressions of intercellular signallings (GATAs [3/4/6], Jagged1/2, notch1/2 and Snail/Zeb1/N-cadherin/vimentin/fibronectin/α-SMA/p-Smad2) were significantly upregulated in TGF-ß/monocrotaline-treated HUVECs that were significantly reversed by PTU treatment (all p < 0.001). By Day 42, the results of animal study demonstrated that the right-ventricular systolic-blood-pressure (RVSBP), RV weight (RVW) and lung injury/fibrotic scores were significantly increased in MCT group than sham-control (SC) that were reversed in MCT + PTU groups, whereas arterial oxygen saturation (%) and vasorelaxation/nitric oxide production of PA exhibited an opposite pattern of RVW among the groups (all p < 0.0001). The protein expressions of hypertrophic (ß-MHC)/pressure-overload (BNP)/oxidative-stress (NOX-1/NOX-2) biomarkers in RV and the protein expressions of intercellular signalling (GATAs3/4/6, Jagged1/2, notch1/2) and endMT markers (Snail/Zeb1/N-cadherin/vimentin/fibronectin/TGF-ß/α-SMA/p-Smad2) in lung parenchyma displayed an identical pattern of RVW among the groups (all p < 0.0001). Jagged-Notch-GATAs signalling, endMT markers and RVSBP that were increased in PAH were suppressed by PTU.

Cuproptosis-related LncRNAs signature as biomarker of prognosis and immune infiltration in pancreatic cancer

Background: Pancreatic cancer (PC) is a malignant gastrointestinal tumor with a terrible prognosis. Cuproptosis is a recently discovered form of cell death. This study is intended to explore the relationship between cuproptosis-related lncRNAs (CRLncs) signature with the prognosis and the tumor microenvironment (TME) of PC. Methods: Transcript sequencing data of PC samples with clinical information were obtained from the Cancer Genome Atlas (TCGA). Univariate Cox regression analysis and LASSO regression analysis were employed to construct the prognostic signature based on CRLncs associated with PC survival. A nomogram was created according to this signature, and the signaling pathway enrichment was analyzed. Subsequently, we explored the link between this prognostic signature with the mutational landscape and TME. Eventually, drug sensitivity was predicted based on this signature. Results: Forty-six of 159 CRLncs were most significantly relevant to the prognosis of PC, and a 6-lncRNA prognostic signature was established. The expression level of signature lncRNAs were detected in PC cell lines. The AUC value of the ROC curve for this risk score predicting 5-year survival in PC was .944, which was an independent prognostic factor for PC. The risk score was tightly related to the mutational pattern of PC, especially the driver genes of PC. Single-sample gene set enrichment analysis (ssGSEA) demonstrated a significant correlation between signature with the TME of PC. Ultimately, compounds were measured for therapy in high-risk and low-risk PC patients, respectively. Conclusion: A prognostic signature of CRLncs for PC was established in the current study, which may serve as a promising marker for the outcomes of PC patients and has important forecasting roles for gene mutations, immune cell infiltration, and drug sensitivity in PC.

Targeting the DLL/Notch Signaling Pathway in Cancer: Challenges and Advances in Clinical Development

The DLL/Notch signaling pathway plays an important role in cancer as a key driver in maintaining cancer stemness and inducing tumor angiogenesis. Many different types of DLL/Notch inhibitors have been developed and explored in clinical trials for cancer treatment, including small-molecule compounds to inhibit gamma-secretase and antibodies targeting Notch ligands or receptors. Despite promising efficacy of these inhibitors in preclinical studies, the overall clinical outcomes have been insufficient to advance to the next stage of clinical development primarily due to safety concerns or modest efficacy. To overcome the narrow therapeutic window of DLL/Notch inhibitors, diverse strategies for improving the balance between the safety and efficacy are currently being explored. Here, we review the clinical perspective and potential of DLL/Notch inhibitors as anticancer agents based on recent results from multiple clinical studies. An antibody specifically targeting Notch ligands or receptors may offer a better approach to reduce concerns about toxicity derived from broad-spectrum DLL/Notch blockers. In addition, combination therapy with an angiogenesis inhibitor targeting VEGF could be a better option for increasing anticancer efficacy. Taken together, the results of clinical trials suggest a bispecific antibody blocking the DLL/Notch and VEGF/VEGFR signaling pathways as a promising approach for effective anticancer treatment.

Inactivation of Notch4 Attenuated Pancreatic Tumorigenesis in Mice

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

Significance

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

Inhibition of Arid1a increases stem/progenitor cell-like properties of liver cancer

ARID1A, a key subunit of the SWI/SNF chromatin remodeling complex, exhibits recurrent mutations in various types of human cancers, including liver cancer. However, the function of ARID1A in the pathogenesis of liver cancer remains controversial. Here, we demonstrate that Arid1a knockout may result in states of different cell differentiation, as indicated by single-cell RNA sequencing (scRNA-seq) analysis. Bulk RNA-seq also revealed that Arid1a deficiency upregulated these genes related to cell stemness and differentiation, but downregulated genes related to the hepatic functions. Furthermore, we confirmed that deficiency of Arid1a increased the expression of hepatic stem/progenitor cell markers, such as Cd133 and Epcam, and enhanced the self-renewal ability of cells. Mechanistic studies revealed that Arid1a loss remodeled the chromatin accessibility of some genes related to liver functions. Thus, Arid1a deficiency might contribute to cancer development by increasing the number of stem/progenitor-like cells through dysregulating the expression of these genes related to cell stemness, differentiation and liver functions.

Development of anti DLL4 Nanobody fused to truncated form of Pseudomonas exotoxin: As a novel immunotoxin to inhibit of cell proliferation and neovascularization

Targeted tumor therapy is an attractive approach for cancer treatment. Delta-like ligand 4 (DLL4) is overexpressed in tumor vasculature and plays a pivotal role in tumor neovascular development and angiogenesis during tumor progression. Immunotoxins due to their superior cell-killing ability and the relative simplicity of their preparation, have great potential in the clinical treatment of cancer. The aim of this study was to develop a novel immunotoxin against DLL4 as a cell cytotoxic agent and angiogenesis maturation inhibitor. In present study, an immunotoxin, named DLL4Nb-PE, in which a Nanobody as targeting moiety fused to the Pseudomonas exotoxin A (PE) was constructed, expressed and assessed by SDS-PAGE, western blotting, ELISA and flowcytometry. The functional assessment was carried out via MTT, apoptosis and chicken chorioallantoic membrane (CAM) assays. It was demonstrated DLL4Nb-PE specifically binds to DLL4 and recognizes DLL4-expressing MKN cells. The cytotoxicity assays showed that this molecule could induce apoptosis and kill DLL4 positive MKN cells. In addition, it inhibited neovascularization in the chicken chorioallantoic membrane. Our findings indicate designed anti-DLL4 immunotoxin has valuable potential for application to the treatment of tumors with high DLL4 expression.

Delta-like canonical Notch ligand 3 as a potential therapeutic target in malignancies: A brief overview

Delta‐like canonical Notch ligand 3 (DLL3) is a member of the Delta/Serrate/Lag2 (DSL) Notch receptor ligand family and plays a crucial role in Notch signaling, which influences various cellular processes including differentiation, proliferation, survival, and apoptosis. DLL3 is expressed throughout the presomitic mesoderm and is localized to the rostral somatic compartments; mutations in DLL3 induce skeletal abnormalities such as spondylocostal dysostosis. Recently, DLL3 has attracted interest as a novel molecular target due to its high expression in neuroendocrine carcinoma of the lung. Moreover, a DLL3‐targeting Ab‐drug conjugate, rovalpituzumab tesirine (ROVA‐T), has been developed as a new treatment with proven antitumor activity. However, the development of ROVA‐T was suspended because of shorter overall survival compared to topotecan, the second‐line standard treatment. Thus, several studies on the mechanism and function of DLL3 in several malignancies are underway to find a new strategy for targeting DLL3. In this review, we discuss the roles of DLL3 in various malignancies and the future perspectives of DLL3‐related research, especially as a therapeutic target.

CDK5 positively regulates Notch1 signaling in pancreatic cancer cells by phosphorylation

The marked overexpression of cyclin‐dependent kinase 5 (CDK5) or Notch1 receptor, which plays critical roles in pancreatic ductal adenocarcinoma (PDAC) development, has been detected in numerous PDAC cell lines and tissues. Although, a previous study has demonstrated that CDK5 inhibition disrupts Notch1 functions in human umbilical vein endothelial cells, the mechanism underlying Notch1 activation regulated by CDK5 remains unclear. Herein, we identified a physical interaction between CDK5 and Notch1 in PDAC cells, with the Notch1 peptide phosphorylated by CDK5/p25 kinase. CDK5 blockade resulted in the profound inhibition of Notch signaling. Accordingly, CDK5 inhibition sensitized PDAC cell proliferation and migration following Notch inhibition. In conclusion, CDK5 positively regulates Notch1 function via phosphorylation, which in turn promotes cell proliferation and migration. The combinational inhibition of CDK5 and Notch signaling may be an effective strategy in the treatment of PDAC.

Pancreatic Cancer and Therapy: Role and Regulation of Cancer Stem Cells

Despite significant improvements in clinical management, pancreatic cancer (PC) remains one of the deadliest cancer types, as it is prone to late detection with extreme metastatic properties. The recent findings that pancreatic cancer stem cells (PaCSCs) contribute to the tumorigenesis, progression, and chemoresistance have offered significant insight into the cancer malignancy and development of precise therapies. However, the heterogeneity of cancer and signaling pathways that regulate PC have posed limitations in the effective targeting of the PaCSCs. In this regard, the role for K-RAS, TP53, Transforming Growth Factor-β, hedgehog, Wnt and Notch and other signaling pathways in PC progression is well documented. In this review, we discuss the role of PaCSCs, the underlying molecular and signaling pathways that help promote pancreatic cancer development and metastasis with a specific focus on the regulation of PaCSCs. We also discuss the therapeutic approaches that target different PaCSCs, intricate mechanisms, and therapeutic opportunities to eliminate heterogeneous PaCSCs populations in pancreatic cancer.

A review: hippo signaling pathway promotes tumor invasion and metastasis by regulating target gene expression

BACKGROUND

The Hippo pathway is widely considered to inhibit cell growth and play an important role in regulating the size of organs. However, recent studies have shown that abnormal regulation of the Hippo pathway can also affect tumor invasion and metastasis. Therefore, finding out how the Hippo pathway promotes tumor development by regulating the expression of target genes provides new ideas for future research on targeted drugs that inhibit tumor progression.

METHODS

PubMed, Embase, Web of Science, and the Cochrane Library were systematically searched.

RESULTS

The search strategy identified 1892 hits and 196 publications were finally included in this review. As the core molecule of the Hippo pathway, YAP/TAZ are usually highly expressed in tumors that undergo invasion and migration and are accompanied by abnormally strong nuclear metastasis. Through its interaction with nuclear transcription factors TEADs, it directly or indirectly regulates and the expressions of target genes related to tumor metastasis and invasion. These target genes can induce the formation of invasive pseudopodia in tumor cells, reduce intercellular adhesion, degrade extracellular matrix (ECM), and cause epithelial-mesenchymal transition (EMT), or indirectly promote through other signaling pathways, such as mitogen-activated protein kinases (MAPK), TGF/Smad, etc, which facilitate the invasion and metastasis of tumors.

CONCLUSION

This article mainly introduces the research progress of YAP/TAZ which are the core molecules of the Hippo pathway regulating related target genes to promote tumor invasion and metastasis. Focus on the target genes that affect tumor invasion and metastasis, providing the possibility for the selection of clinical drug treatment targets, to provide some help for a more in-depth study of tumor invasion and migration mechanism and the development of clinical drugs.

Pancreatic adenocarcinoma: molecular drivers and the role of targeted therapy

Prognosis from pancreatic ductal adenocarcinoma (PDAC) continues to be poor despite the many efforts channeled to improve its management. Although the mainstay treatment is still traditional chemotherapy, recent advances highlighted a promising potential for targeted therapy in the management of this disease. Those advances emphasize the significance of timely genomic profiling of tumor tissue as well as germline testing of patients to identify potential markers of targeted therapy. While targeted therapy is reserved for a relatively small subset of patients with PDAC, ongoing research is uncovering additional markers, and targeted agents, that will hopefully translate to better outcomes for patients.

From the perspective of Traditional Chinese Medicine: Treatment of mental disorders in COVID-19 survivors

PURPOSE

The aim of this study is to explore the possible benefits of traditional Chinese medicine on the pathogenesis of psychological and mental health of COVID-19 survivors.

METHODS

A literature search was conducted to confirm the effects of COVID-19 on psychological and mental health of survivors. In addition to this, on the basis of signs and symptoms, TCM were used on treat mental disorder as per suggested clinical and animal experimental data plus relevant records in classical Chinese medicine books written by Zhang Zhongiing during Han Dynasty. A series of treatment plans were prescribed for COVID-19 survivors with psychological and mental disorders.

RESULTS

According to previous extensive studies focusing on effects on mental health of survivors, high incidence was observed in severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS) survivors. During investigations of mental health of COVID-19 patients and survivors, it is observed that they also had symptoms of mental disorders and immune dysfunction. Furthermore, it was also proposed that depression, anxiety and post-traumatic stress disorder (PTSD) were most common mental disorders requiring special attention after the recovery from COVID-19. The symptoms of COVID-19 were analyzed, and the TCM syndrome of the depression, anxiety and PTSD after recovered from COVID19 was interpreted as internal heat and Yin deficiency. These three mental disorders pertains the category of "Lily disease", "hysteria" and "deficient dysphoria" in TCM.

CONCLUSION

Lily Bulb, Rhizoma Anemarrhena Decoction and Ganmai Dazao Decoction were used to treat depression. Suanzaoren Decoction, Huanglian Ejiao Decoction and Zhizi Chi Decoction were suggested for anxiety. Moreover, Lily Bulb, Rehmannia Decoction and Guilu Erxian Decoction were the formula for PTSD.

Two engineered site-specific antibody-drug conjugates, HLmD4 and HLvM4, have potent therapeutic activity in two DLL4-positive tumour xenograft models

The humanized Delta-like 4 (DLL4) monoclonal antibody H3L2 with a quite high affinity for hrDLL4 inhibits the DLL4-mediated human umbilical vein endothelial cell (HUVEC) phenotype, inducing dysfunctional angiogenesis and tumour cell apoptosis, which effectively arrests breast cancer cell growth in vivo. To develop a more effective therapy, an engineered cysteine residue at alanine 121 (Kabat numbering) on each H3L2 heavy chain or at valine 207 (Kabat numbering) on each H3L2 light chain was established by site-directed mutagenesis. Three engineered antibodies, THL4, TH2 and TL2, were identified, and the specific-site antibody-drug conjugates (ADCs) THL4-mpeoDM1 (named HLmD4), TH2-mpeoDM1 (named HmD2), TL2-mpeoDM1 (named LmD2) and THL4-vcMMAE (named HLvM4), were produced, which exhibit much more potent antitumour activity than the naked antibody. The engineered ADCs can be directed against DLL4 and effectively internalized, followed by the release of small molecule cytotoxic agents, e.g., DM1 or MMAE, into the cytosol, which inhibit the synthesis of microtubules and induce G2/M phase growth arrest and cell death through the induction of apoptosis. ADC-conjugated DM1 was highly potent against DLL4-expressing cells in vitro. We systematically compared the in vitro potency and the in vivo preclinical efficacy and safety profiles of the heterogeneous conventional ADC, H3L2-mpeoDM1 (named JmD4) with that of the homogeneous engineered conjugate HLmD4. The engineered anti-DLL4 ADCs, particularly HLmD4, showed more potent antitumour activity than Docetaxel and superior safety compared with JmD4 in two xenograft tumour models. Our findings indicate that engineered ADCs have promising potential as effective preclinical therapies for cancers.

Stem cells in cancer initiation and progression

Bajaj et al. review how cancers originate, how their heterogeneity is linked to cancer stem cells, and the signals fundamental to driving these processes.

While standard therapies can lead to an initial remission of aggressive cancers, they are often only a transient solution. The resistance and relapse that follows is driven by tumor heterogeneity and therapy-resistant populations that can reinitiate growth and promote disease progression. There is thus a significant need to understand the cell types and signaling pathways that not only contribute to cancer initiation, but also those that confer resistance and drive recurrence. Here, we discuss work showing that stem cells and progenitors may preferentially serve as a cell of origin for cancers, and that cancer stem cells can be key in driving the continued growth and  functional heterogeneity of established cancers. We also describe emerging evidence for the role of developmental signals in cancer initiation, propagation, and therapy resistance and discuss how targeting these pathways may be of therapeutic value.

Jagged2 progressively increased expression from Stage I to III of Bladder Cancer and Melatonin-mediated downregulation of Notch/Jagged2 suppresses the Bladder Tumorigenesis via inhibiting PI3K/AKT/mTOR/MMPs signaling

Background: This study assessed the expression of Jagged2 in human bladder cancer (BC) tested the hypothesis that melatonin (Mel) inhibited the tumorigenesis of BC cells mainly through downregulating the Notch/Jagged2 and PI3K/AKT/mTOR/MMPs^(2&9) signaling pathways.

Methods and Results: Tissue array from BC patients showed that the gene and protein expressions of JAG2/Jagged2 were significantly upregulated from T1 to T3 (primary tumor size) and from stage I to III (all p<0.001). In vitro study showed that in BC cell line of UMUC3, the cellular and protein expressions of Jagged2 were significantly attenuated in Mel-treated UMUC3 and further attenuated in UMUC3 shRNA silenced Notch/JAG2 (UMUC3^KD) than in UMUC3 only (all p<0.0001). The protein expressions of Notch/Jagged2/MMPs^(2&9)/PI3K/p-AKT/mTOR/p53/ratio of LC3BII/LC3B-I were significantly progressively reduced from UMUC3 to UMUC3+Mel/1.0mM, further to UMUC3+Mel/2.0mM and furthermore to UMUC3^KD (all p<0.0001). The cell proliferation/invasion/colony formation/healing-process were significantly inhibited in Mel-treated/2.0mM UMUC3 and further significantly inhibited in UMUC3^KD regardless of Mel treatment as compared with UMUC3 only (all p<0.0001). By day 28 after UMUC3 implanted into nude mouse back, the BC weight/volume were significantly reduced in UMUC3+Mel (100 mg/kg/day) and furthermore reduced in UMUC3^KD (all p<0.0001) as compared with UMUC3 only (all p<0.0001). The cellular (MMPs^(2&9)/Notch/Jagged2) and protein (Notch/Jagged2/PI3K/p-AKT/mTOR/MMPs^(2&9)) exhibited a similar trend, whereas the PTEN protein level exhibited an opposite pattern of PI3K among three groups (all p<0.0001).

Conclusion: Notch/Jagged-PI3K/p-AKT/mTOR/MMPs is one essential signaling pathway for BC survival, proliferation and invasion that were remarkably suppressed by Mel treatment.

GPR50 Promotes Hepatocellular Carcinoma Progression via the Notch Signaling Pathway through Direct Interaction with ADAM17

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide, and it is thus critical to identify novel molecular biomarkers of HCC prognosis and elucidate the molecular mechanisms underlying HCC progression. Here, we show that G-protein-coupled receptor 50 (GPR50) in HCC is overexpressed and that GPR50 knockdown may downregulate cancer cell progression through attenuation of the Notch signaling pathway. GPR50 knockdown was found to reduce HCC progression by inactivating Notch signaling in a ligand-independent manner through a disintegrin and metalloproteinase metallopeptidase domain 17 (ADAM17), a proteolytic enzyme that cleaves the Notch receptor, which was corroborated by GPR50 overexpression in hepatocytes. GPR50 silencing also downregulated transcription and translation of ADAM17 through the AKT/specificity protein-1 (SP1) signaling axis. Notably, GPR50 was found to directly interact with ADAM17. Overall, we demonstrate a novel GPR50-mediated regulation of the ADAM17-Notch signaling pathway, which can provide insights into HCC progression and prognosis and development of Notch-based HCC treatment strategies.

Top Notch Targeting Strategies in Cancer: A Detailed Overview of Recent Insights and Current Perspectives

Evolutionarily conserved Notch plays a critical role in embryonic development and cellular self-renewal. It has both tumour suppressor and oncogenic activity, the latter of which is widely described. Notch-activating mutations are associated with haematological malignancies and several solid tumours including breast, lung and adenoid cystic carcinoma. Moreover, upregulation of Notch receptors and ligands and aberrant Notch signalling is frequently observed in cancer. It is involved in cancer hallmarks including proliferation, survival, migration, angiogenesis, cancer stem cell renewal, metastasis and drug resistance. It is a key component of cell-to-cell interactions between cancer cells and cells of the tumour microenvironment, such as endothelial cells, immune cells and fibroblasts. Notch displays diverse crosstalk with many other oncogenic signalling pathways, and may drive acquired resistance to targeted therapies as well as resistance to standard chemo/radiation therapy. The past 10 years have seen the emergence of different classes of drugs therapeutically targeting Notch including receptor/ligand antibodies, gamma secretase inhibitors (GSI) and most recently, the development of Notch transcription complex inhibitors. It is an exciting time for Notch research with over 70 cancer clinical trials registered and the first-ever Phase III trial of a Notch GSI, nirogacestat, currently at the recruitment stage.

The Role of DLLs in Cancer: A Novel Therapeutic Target

Delta-like ligands (DLLs) control Notch signaling. DLL1, DLL3 and DLL4 are frequently deregulated in cancer and influence tumor growth, the tumor vasculature and tumor immunity, which play different roles in cancer progression. DLLs have attracted intense research interest as anti-cancer therapeutics. In this review, we discuss the role of DLLs in cancer and summarize the emerging DLL-relevant targeting methods to aid future studies.

Overexpression of JAG2 is related to poor outcomes in oral squamous cell carcinoma

OBJECTIVES

JAG2 is one of Notch ligands, which recently appear to exert various carcinogenesis. In the present study, we aimed to unveil the relation of JAG2 expression and clinicopathological features in oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

We examined JAG2 expression in OSCC plus adjacent nontumorous epithelia in eight patients. Ninety-one OSCC tissue specimens were immunohistochemically stained with specific antibodies to JAG2. The immunoreactivities of JAG2 were correlated with clinicopathological factors, including the prognosis of patients. Chi-square test, Kaplan-Meier survival, and Cox proportional hazard analysis were used to determine the statistical value of JAG2 expression in OSCC.

RESULTS

JAG2 mRNA expression was much expressed in OSCC tissues compared with adjacent tissue specimens in five of eight patients. JAG2 immunoreactivity was found at invasion front in 31 of 91 OSCC. JAG2 immunoreactivity was significantly associated with age, less than 50 years old of patients (P = .048). Kaplan-Meier analysis demonstrated that the patients with JAG2 immunoreactvty have a short overall survival. With the Cox proportional hazard regression mode, the independent factors predictive of poor overall survival included JAG2 immunoreactivity (P < .05).

CONCLUSIONS

The present findings suggest that JAG2 overexpression, especially at the cancer invasion front, has potential prognostic value.

Frequent Activation of Notch Signaling Pathway in Colorectal Cancers and Its Implication in Patient Survival Outcome

Colorectal cancer is a major health concern as it ranks third in incidence and second major cause of cancer-related deaths worldwide. A leading cause of treatment failure has been attributed to cancer stem cells that can invariably resist existing chemotherapeutic regimens. Notch signaling pathway has been involved in the maintenance of stem cells besides being crucial in cell fate decision and embryonic development. This pathway has also been implicated in several human malignancies including colorectal cancer. We investigated mRNA expression of four Notch receptors (Notch1–4), five ligands (Jag1, Jag2, Dll1, Dll3, and Dll4), and four target genes (Hes1, Hes5, Hey1, and Hey2) using highly specific TaqMan gene expression assays in colorectal adenomas and cancers. Upregulated expression of Notch receptors ranged between 29 and 73% in colorectal cancers and between 11 and 56% in adenomas. Expression of Notch3 and Notch4 receptors was significantly higher in colorectal cancers compared to normal and adenoma tissues. The Jagged and Delta-like ligands were overexpressed between 25 and 52% in colorectal cancers, while in adenomas, it ranged between 0 and 33%. Combining the data for upregulation of receptors and ligands suggests that 86% colorectal cancers and 56% adenomas exhibited overexpression of Notch pathway genes in our cohort. Notch target genes were upregulated between 24 and 33% in colorectal cancers and between 11 and 22% in adenomas. Collating upregulation of Notch receptors and ligands with the target genes showed concordance in 58% colorectal tumors. Additionally, we evaluated expression of Notch receptors, ligands, and target genes with prognosis using the TCGA mRNA expression dataset. Patients overexpressing Notch3, Notch4, and Hey1 had significantly poorer overall survival relative to those having lower levels of these genes. Taken together, Notch signaling components are aberrantly overexpressed in colorectal tumors, and development of therapeutics targeting the Notch pathway may prove to be beneficial in the management of colorectal cancers.

Hypoxic niches are endowed with a protumorigenic mechanism that supersedes the protective function of PTEN

Head and neck squamous cell carcinoma (HNSCC) is the sixth most common malignancy worldwide and is characterized by a fast-paced growth. Like other solid tumors, the HNSCC growth rate results in the development of hypoxic regions identified by the expression of hypoxia-inducible factor 1α (HIF-1α). Interestingly, clinical data have shown that pharmacological induction of intratumoral hypoxia caused an unexpected rise in tumor metastasis and the accumulation of cancer stem cells (CSCs). However, little is known on the molecular circuitries involved in the presence of intratumoral hypoxia and the augmented population of CSCs. Here we explore the impact of hypoxia on the behavior of HNSCC and define that the controlling function of phosphatase and tensin homolog (PTEN) over HIF-1α expression and CSC accumulation are de-regulated during hypoxic events. Our findings indicate that hypoxic niches are poised to accumulate CSCs in a molecular process driven by the loss of PTEN activity. Furthermore, our data suggest that targeted therapies aiming at the PTEN/PI3K signaling may constitute an effective strategy to counteract the development of intratumoral hypoxia and the accumulation of CSCs.-Nascimento-Filho, C. H. V., Webber, L. P., Borgato, G. B., Goloni-Bertollo, E. M., Squarize, C. H., Castilho, R. M. Hypoxic niches are endowed with a protumorigenic mechanism that supersedes the protective function of PTEN.

Therapeutic Targeting of the Notch Pathway in Glioblastoma Multiforme

BACKGROUND

Glioblastoma (GBM) is the most common and deadly form of brain tumor. After standard treatment of resection, radiotherapy, and chemotherapy, the 5-year survival is <5%. In recent years, research has uncovered several potential targets within the Notch signaling pathway, which may lead to improved patient outcomes.

METHODS

A literature search was performed for articles containing the terms "Glioblastoma" and "Receptors, Notch" between 2003 and July 2015. Of the 62 articles retrieved, 46 met our criteria and were included in our review. Nine articles were identified from other sources and were subsequently included, leaving 55 articles reviewed.

RESULTS

Of the 55 articles reviewed, 47 used established human GBM cell lines. Seventeen articles used human GBM surgical samples. Forty-five of 48 articles that assessed Notch activity showed increased expression in GBM cell lines. Targeting the Notch pathway was carried out through Notch knockdown and overexpression and targeting δ-like ligand, Jagged, γ-secretase, ADAM10, ADAM17, and Mastermindlike protein 1. Arsenic trioxide, microRNAs, and several other compounds were shown to have an effect on the Notch pathway in GBM. Notch activity in GBM was also shown to be associated with hypoxia and certain cancer-related molecular pathways such as PI3K/AKT/mTOR and ERK/MAPK. Most articles concluded that Notch activity amplifies malignant characteristics in GBM and targeting this pathway can bring about amelioration of these effects.

CONCLUSIONS

Recent literature suggests targeting the Notch pathway has great potential for future therapies for GBM.

Combination of laser microdissection, 2D-DIGE and MALDI-TOF MS to identify protein biomarkers to predict colorectal cancer spread

Biomarkers are urgently required to support current histological staging to provide additional accuracy in stratifying colorectal cancer (CRC) patients according to risk of spread to properly assign adjuvant chemotherapy after surgery. Chemotherapy is given to patients with stage III to reduce the risk of recurrence but is controversial in stage II patients. Up to 25% of stage II patients will relapse within 5 years after tumor removal and when this occurs cure is seldom possible. The aim of this study was to identify protein biomarkers to stratify risk of spread of CRC patients. Laser micro-dissection was used to isolate cancer cells from primary colorectal tumors of stage II patients which did or did not metastasize within 5 years after surgical resection. Protein expression differences between two groups of tumors were profiled by 2D-DIGE with saturation CyDye labeling and identified using MALDI-TOF mass spectrometry. Evaluation of protein candidates was conducted using tissue micro array (TMA) immunohistochemistry on 125 colorectal tumor tissue samples of different stages. A total of 55 differentially expressed proteins were identified. Ten protein biomarkers were chosen based on p value and ratio between non metastasized and metastazised groups and evaluated on 125 tissues using TMA immunohistochemistry. Expression of HLAB, protein 14-3-3β, LTBP3, ADAMTS2, JAG2 and NME2 on tumour cells was significantly associated with clinical parameters related to tumour progression, invasion and metastasis. Kaplan–Meier survival curve showed strong expression of six proteins was associated with good CRC specific survival. Expression of HLAB, ADAMTS2, LTBP3, JAG2 and NME2 on tumour cells, was associated with tumour progression and invasion, metastasis and CRC specific survival may serve as potential biomarkers to stratify CRC patients into low and high risk of tumour metastasis. Combined methods of laser microdissection, 2D DIGE with saturation labelling and MALDI-TOF MS proved to be resourceful techniques capable of identifying protein biomarkers to predict risk of spread of CRC to liver.

Hypoxia-inducible factor-2α directly promotes BCRP expression and mediates the resistance of ovarian cancer stem cells to adriamycin

Ovarian cancer stem cells (OCSCs) are sources of tumor chemoresistance and recurrence. A hypoxic microenvironment contributes to the chemoresistance of cancer stem cells (CSCs), but the underlying mechanism is not fully understood yet. Here, we show that increased HIF-2α expression is associated with enhanced stemness of OCSCs and poor outcomes in ovarian cancer patients. OVCAR-3 and CAOV-3 sphere-forming (OVCAR-3 S and CAOV-3 S) cells with OCSC-like properties showed strong resistance to adriamycin (ADR). Hypoxia (1% O₂ ) induced high expression of both HIF-1α and especially HIF-2α, and increased the resistance of OVCAR-3 S and CAOV-3 S cells to ADR. Notably, treatment with ADR further increased the expression of HIF-2α, but not that of HIF-1α. Knockdown of HIF-2α expression substantially attenuated the resistance of OVCAR-3 S and CAOV-3 S cells to ADR, and the HIF-2α overexpression had the opposite effect. Furthermore, in mouse models xenografted with OCSCs, HIF-2α depletion significantly inhibited tumor growth and sensitized OCSCs to ADR in vivo. Mechanistically, HIF-2α directly promotes transcription/expression of BCRP, a gene encoding a transporter protein responsible for pumping drugs (e.g., ADR) out of cells, which in turn increases drug resistance due to increased drug transportation. Collectively, our studies reveal a novel drug-resistant mechanism in ovarian cancer by which hypoxia (and ADR treatment)-induced HIF-2α overexpression endows OCSCs with resistance to ADR by promoting BCRP expression and ADR transportation. Therefore, targeting the HIF-2α/BCRP axis holds therapeutic potential for treating drug-resistant ovarian cancer.

miR-181b/Notch2 overcome chemoresistance by regulating cancer stem cell-like properties in NSCLC

Background

Lung cancer stem cells have the ability to self-renew and are resistant to conventional chemotherapy. MicroRNAs (miRNAs) regulate and control the expression and function of many target genes; therefore, miRNA disorders are involved in the pathogenesis of human diseases, such as cancer. However, the effects of miRNA dysregulation on tumour stemness and drug resistance have not been fully elucidated. miR-181b has been reported to be a tumour suppressor miRNA and is associated with drug-resistant non-small cell lung cancer.

Methods

Cancer stem cell (CSC)-like properties were tested by a cell proliferation assay and flow cytometry; miR-181b expression was measured by real-time PCR; and Notch2 and related proteins were detected by Western blotting and immunohistochemistry. A mouse xenograft model was also established.

Results

In this study, we found that ectopic miR-181b expression suppressed cancer stem cell properties and enhanced sensitivity to cisplatin (DDP) treatment by directly targeting Notch2. miR-181b could inactivate the Notch2/Hes1 signalling pathway. In addition, tumours from nude mice treated with miR-181b were significantly smaller than tumours from mice treated with control agomir. Decreased miR-181b expression and increased Notch2 expression were observed to have a significant relationship with overall survival (OS) and CSC-like properties in non-small cell lung cancer (NSCLC) patients.

Conclusions

This study elucidates an important role of miR-181b in the regulation of CSC-like properties, suggesting a potential therapeutic target for overcoming drug resistance in NSCLC.

Electronic supplementary material

The online version of this article (10.1186/s13287-018-1072-1) contains supplementary material, which is available to authorized users.

HIF-2α promotes conversion to a stem cell phenotype and induces chemoresistance in breast cancer cells by activating Wnt and Notch pathways

BACKGROUND

Hypoxic tumor microenvironment and maintenance of stemness contribute to drug resistance in breast cancer. However, whether Hypoxia-inducible factor-2α (HIF-2α) in hypoxic tumor microenvironment mediates conversion to a stem cell phenotype and chemoresistance of breast tumors has not been elucidated.

METHODS

The mRNA and protein expressions of HIF-1α, HIF-2α, Wnt and Notch pathway were determined using qRT-PCR and western blot. Cell viability and renew ability were assessed by MTT, Flow cytometric analysis and soft agar colony formation.

RESULTS

In our study, acute hypoxia (6-12 h) briefly increased HIF-1α expression, while chronic hypoxia (48 h) continuously enhanced HIF-2α expression and induced the resistance of breast cancer cells to Paclitaxel (PTX). Furthermore, HIF-2α overexpression induced a stem cell phenotype, the resistance to PTX and enhanced protein expression of stem cell markers, c-Myc, OCT4 and Nanog. Most importantly, Wnt and Notch signaling, but not including Shh, pathways were both activated by HIF-2α overexpression. Dickkopf-1 (DKK-1), a Wnt pathway inhibitor, and L685,458, an inhibitor of the Notch pathway, reversed the resistance to PTX and stem phenotype conversion induced by HIF-2α overexpression. In addition, HIF-2α overexpression enhanced tumorigenicity and resistance of xenograft tumors to PTX, increased activation of the Wnt and Notch pathways and induced a stem cell phenotype in vivo.

CONCLUSION

In conclusion, HIF-2α promoted stem phenotype conversion and induced resistance to PTX by activating Wnt and Notch pathways.

Novel Targets in Pancreatic Cancer Therapy - Current Status and Ongoing Translational Efforts

Pancreatic ductal adenocarcinoma (PDAC, pancreatic cancer) carries one of the poorest overall prognoses of all human malignancies known to date. Despite the introduction of novel therapeutic regimens, the outcome has not markedly improved over the past decades, the incidence rates are almost identical to the mortality rates, and PDAC is projected to soon become the second most common cause of cancer-related mortality in Western countries. Despite this clear medical need to develop novel therapeutic strategies against this dire malady, this need has so far not been addressed with sufficient institutional attention and support in terms of research funding and strategical programs. Given the still growing life expectancy and projected demographic changes with a growing proportion of senior citizens in many European societies, this discrepancy is likely to become even more pressing in the future. This article provides a brief overview of ongoing preclinical efforts to identify novel targets and, based on this, to develop novel strategies to treat advanced pancreatic cancer and improve survival and the quality of life of patients suffering from this malignancy.

Clinical significance of expression of Jagged 2 in colon cancer

AIM

To detect the expression of Jagged 2 in human colon carcinoma and to analyze its clinical significance.

METHODS

The expression of Jagged 2 mRNA and protein in 42 cases of human colon carcinoma and adjacent non-tumorous tissues was detected by real-time quantitative PCR, immunohistochemistry, and Western blot. The relationship between Jagged 2 expression and clinicopathologic characteristics of colon carcinoma was then analyzed.

RESULTS

Jagged 2 mRNA and protein can be detected in colon carcinoma tissues and adjacent non-tumorous tissues. The expression of Jagged 2 mRNA and protein in colon carcinoma was significantly higher than that in matched adjacent non-tumorous tissues (P < 0.05). Immunohistochemical staining demonstrated that the percentage of Jagged 2 positive cells in colon carcinoma was significantly higher than that in matched adjacent non-tumorous tissues (85.7% vs 33.3%, χ² = 23.92, P < 0.01), and the expression of Jagged 2 had a significant correlation with histopathological grade, Duke's stage, depth of invasion, and lymph node metastasis (P < 0.05).

CONCLUSION

The expression of Jagged 2 is up-regulated in colon carcinoma, suggesting that Jagged 2 may be involved in the carcinogenesis, invasion, and metastasis of colon cancer.

The Role of Notch Signaling and Leptin-Notch Crosstalk in Pancreatic Cancer

There is accumulating evidence that deregulated Notch signaling affects cancer development, and specifically pancreatic cancer (PC) progression. Notch canonical and non-canonical signaling has diverse impact on PC. Moreover, the actions of RBP-Jk (nuclear partner of activated Notch) independent of Notch signaling pathway seem to affect differently cancer progression. Recent data show that in PC and other cancer types the adipokine leptin can modulate Notch/RBP-Jk signaling, thereby, linking the pandemic obesity with cancer and chemoresistance. The potential pivotal role of leptin on PC, and its connection with Notch signaling and chemoresistance are still not completely understood. In this review, we will describe the most important aspects of Notch-RBP-Jk signaling in PC. Further, we will discuss on studies related to RBP-Jk-independent Notch and Notch-independent RPB-Jk signaling. We will also discuss on the novel crosstalk between leptin and Notch in PC and its implications in chemoresistance. The effects of leptin-Notch/RBP-Jk signaling on cancer cell proliferation, apoptosis, and drug resistance require more investigation. Data from these investigations could help to open unexplored ways to improve PC treatment success that has shown little progress for many years.

A phase I trial of the γ-secretase inhibitor MK-0752 in combination with gemcitabine in patients with pancreatic ductal adenocarcinoma

BACKGROUND

The Notch pathway is frequently activated in cancer. Pathway inhibition by γ-secretase inhibitors has been shown to be effective in pre-clinical models of pancreatic cancer, in combination with gemcitabine.

METHODS

A multi-centre, non-randomised Bayesian adaptive design study of MK-0752, administered per os weekly, in combination with gemcitabine administered intravenously on days 1, 8 and 15 (28 day cycle) at 800 or 1000 mg m-2, was performed to determine the safety of combination treatment and the recommended phase 2 dose (RP2D). Secondary and tertiary objectives included tumour response, plasma and tumour MK-0752 concentration, and inhibition of the Notch pathway in hair follicles and tumour.

RESULTS

Overall, 44 eligible patients (performance status 0 or 1 with adequate organ function) received gemcitabine and MK-0752 as first or second line treatment for pancreatic cancer. RP2Ds of MK-0752 and gemcitabine as single agents could be combined safely. The Bayesian algorithm allowed further dose escalation, but pharmacokinetic analysis showed no increase in MK-0752 AUC (area under the curve) beyond 1800 mg once weekly. Tumour response evaluation was available in 19 patients; 13 achieved stable disease and 1 patient achieved a confirmed partial response.

CONCLUSIONS

Gemcitabine and a γ-secretase inhibitor (MK-0752) can be combined at their full, single-agent RP2Ds.

Leptin-Notch signaling axis is involved in pancreatic cancer progression

Pancreatic cancer (PC) shows a high death rate. PC incidence and prognosis are affected by obesity, a pandemic characterized by high levels of leptin. Notch is upregulated by leptin in breast cancer. Thus, leptin and Notch crosstalk could influence PC progression. Here we investigated in PC cell lines (BxPC-3, MiaPaCa-2, Panc-1, AsPC-1), derived tumorspheres and xenografts whether a functional leptin-Notch axis affects PC progression and expansion of pancreatic cancer stem cells (PCSC). PC cells and tumorspheres were treated with leptin and inhibitors of Notch (gamma-secretase inhibitor, DAPT) and leptin (iron oxide nanoparticle-leptin peptide receptor antagonist 2, IONP-LPrA2). Leptin treatment increased cell cycle progression and proliferation, and the expression of Notch receptors, ligands and targeted molecules (Notch1-4, DLL4, JAG1, Survivin and Hey2), PCSC markers (CD24/CD44/ESA, ALDH, CD133, Oct-4), ABCB1 protein, as well as tumorsphere formation. Leptin-induced effects on PC and tumorspheres were decreased by IONP-LPrA2 and DAPT. PC cells secreted leptin and expressed the leptin receptor, OB-R, which indicates a leptin autocrine/paracrine signaling loop could also affect tumor progression. IONP-LPrA2 treatment delayed the onset of MiaPaCa-2 xenografts, and decreased tumor growth and the expression of proliferation and PCSC markers. Present data suggest that leptin-Notch axis is involved in PC. PC has no targeted therapy and is mainly treated with chemotherapy, whose efficiency could be decreased by leptin and Notch activities. Thus, the leptin-Notch axis could be a novel therapeutic target, particularly for obese PC patients.

A three-molecule score based on Notch pathway predicts poor prognosis in non-metastasis clear cell renal cell carcinoma

We constructed a three-molecule score based on the expression of Notch pathway molecules: Jagged1, intracellular Notch1 (ICN1) and Hes1 (JIH score). To assess prognostic value of the JIH score in non-metastasis clear cell renal cell carcinoma (ccRCC), we identified 467 patients who underwent nephrectomy during 2008-2009 as our study population. Immunohistochemistry was used to evaluate the expression of these three molecules. Cox regression models were applied to construct the JIH score, while Kaplan-Meier methods, multivariate analyses and nomogram were used to explore prognostic value of the JIH score. Our result confirmed that JIH score was an independent prognosticator for both overall survival (OS) and recurrence-free survival (RFS). Survival analyses showed that a higher JIH score indicated worse clinical outcomes (JIH score 3: 58.3% and 58.0% for 6-year OS and RFS, respectively; JIH score 0: 96.7% and 91.6% for 6-year OS and RFS, respectively). Nomograms based on JIH score and other conventional clinicopathological features had a better capability in predicting patients with pT1 stage disease for both OS and RFS (84.6% and 83.9%, respectively). The JIH score is a novel prognosticator representing activation of Notch pathway for non-metastasis ccRCC, and raises an alternative strategy for excavating potential biomarkers for signal pathways.

Targeted Therapies for Pancreatic Cancer

Pancreatic cancer is the third leading cause of cancer related death and by 2030, it will be second only to lung cancer. We have seen tremendous advances in therapies for lung cancer as well as other solid tumors using a molecular targeted approach but our progress in treating pancreatic cancer has been incremental with median overall survival remaining less than one year. There is an urgent need for improved therapies with better efficacy and less toxicity. Small molecule inhibitors, monoclonal antibodies and immune modulatory therapies have been used. Here we review the progress that we have made with these targeted therapies.

Overexpression of ankyrin1 promotes pancreatic cancer cell growth

The methylation status of a promoter influences gene expression and aberrant methylation during tumor development has important functional consequences for pancreatic and other cancers. Using methylated CpG island amplification and promoter microarrays, we identified ANK1 as hypomethylated in pancreatic cancers. Expression analysis determined ANK1 as commonly overexpressed in pancreatic cancers relative to normal pancreas. ANK1 was co-expressed with miR-486 in pancreatic cancer cells. Stable knockdown of ANK1 in the pancreatic cancer cell line AsPC1 led to changes in cell morphology, and decreases in colony formation. Stable knockdown of ANK1 also marked reduced the growth of tumors in athymic nude mice. Among patients undergoing pancreaticoduodenectomy, those with pancreatic cancers expressing ANK1 had a poorer prognosis than those without ANK1 expression. These findings indicate a role for ANK1 overexpression in mediating pancreatic cancer tumorigenicity.

Regulation of pancreatic stellate cell activation by Notch3

Background

Activated pancreatic stellate cells (PaSCs) are the key cellular source of cancer-associated fibroblasts in the pancreatic stroma of patients with pancreatic ductal adenocarcinoma (PDAC), however, the activation mechanism of PaSCs is not yet known. The Notch signaling pathway, components of which are expressed in stromal cells, is involved in the fibrosis of several organs, including the lung and liver. In the current study, we investigated whether Notch signal transduction is involved in PaSC activation in PDAC.

Methods

The expression of Notch signaling pathway components in human PDAC was examined via immunohistochemical staining and assessed in mouse PaSCs using RT-qPCR and western blotting. Notch3 expression in both PDAC stromal cells and activated mouse PaSCs was evaluated using immunofluorescence, RT-qPCR and western blotting. The impact of siRNA-mediated Notch3 knockdown on PaSC activation was detected with RT-qPCR and western blotting, and the impact on PaSC proliferation and migration was detected using CCK-8 assays and scratch experiments. The effect of conditioned medium from PaSCs activated with Notch3 siRNA on pancreatic cancer (LTPA) cells was also detected with CCK-8 assays and scratch experiments. The data were analyzed for statistical significance using Student’s t-test.

Results

Notch3 was overexpressed in both human PDAC stromal cells and activated mouse PaSCs, and Notch3 knockdown with Notch3 siRNA decreased the proliferation and migration of mouse PaSCs. The levels of markers related to PaSC activation, such as α-smooth muscle actin (α-SMA), collagen I and fibronectin, decreased in response to Notch3 knockdown, indicating that Notch3 plays an important role in PaSC activation. Furthermore, we confirmed that inhibition of PaSC activation via Notch3 siRNA reduced the proliferation and migration of PaSC-induced mouse pancreatic cancer (LTPA) cells.

Conclusions

Notch3 inhibition in PaSCs can inhibit the activation, proliferation and migration of PaSCs and reduce the PaSC-induced pro-tumorigenic effect. Therefore, Notch3 silencing in PaSCs is a potential novel therapeutic option for patients with PDAC.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3957-2) contains supplementary material, which is available to authorized users.

Molecular subtype specific efficacy of MEK inhibitors in pancreatic cancers

Pancreatic cancer is an increasing cause of cancer related death worldwide. KRAS is the dominant oncogene in this cancer type and molecular rationale would indicate, that inhibitors of the downstream target MEK could be appropriate targeted agents, but clinical trials have failed so far to achieve statistically significant benefit in unselected patients. We aimed to identify predictive molecular biomarkers that can help to define subgroups where MEK inhibitors might be beneficial alone or in combination. Next-generation sequencing data of 50 genes in three pancreatic cancer cell lines (MiaPaCa2, BxPC3 and Panc1) were analyzed and compared to the molecular profile of 138 clinical pancreatic cancer samples to identify the molecular subtypes of pancreatic cancer these cell lines represent. Luminescent cell viability assay was used to determine the sensitivity of cell lines to kinase inhibitors. Western blot was used to analyze the pathway activity of the examined cell lines. According to our cell viability and pathway activity data on these model cell lines only cells harboring the rare G12C KRAS mutation and low EGFR expression are sensitive to single MEK inhibitor (trametinib) treatment. The common G12D KRAS mutation leads to elevated baseline Akt activity, thus treatment with single MEK inhibitors fails. However, combination of MEK and Akt inhibitors are synergistic in this case. In case of wild-type KRAS and high EGFR expression MEK inhibitor induced Akt phosphorylation leads to trametinib resistance which necessitates for MEK and EGFR or Akt inhibitor combination treatment. In all we provide strong preclinical rational and possible molecular mechanism to revisit MEK inhibitor therapy in pancreatic cancer in both monotherapy and combination, based on molecular profile analysis of pancreatic cancer samples and cell lines. According to our most remarkable finding, a small subgroup of patients with G12C KRAS mutation may still benefit from MEK inhibitor monotherapy.

The two novel DLL4-targeting antibody-drug conjugates MvM03 and MGD03 show potent anti-tumour activity in breast cancer xenograft models

The anti-human Delta-like 4 (DLL4) monoclonal antibody MMGZ01 has a high affinity to hrDLL4 and arrests the DLL4-mediated human umbilical vein endothelial cell (HUVEC) phenotype, promotes immature vessels, and effectively reduces breast cancer cell growth in vivo. To develop a much more effective therapy, we conjugated MMGZ01 with two small-molecule cytotoxic agents, i.e., monomethyl auristatin E (MMAE) and doxorubicin (DOX), with different linkers to generate antibody-drug conjugates (ADCs), i.e., MMGZ01-vc-MMAE (named MvM03) and MMGZ01-GMBS-DOX (named MGD03), that are more potent therapeutic agents than naked antibody therapeutic agents. The produced anti-DLL4 ADCs can be effectively directed against DLL4 and internalized. Then, the release of MMAE or DOX into the cytosol can induce G2/M or G0/G1 phase growth arrest and cell death through the induction of apoptosis. In vitro, MvM03 was highly potent and selective against DLL4 cell lines. The anti-DLL4 ADCs, particularly MvM03, showed more potent anti-tumour activity than Docetaxel, which is an inhibitor of the depolymerisation of microtubules, in two xenograft breast cancer tumour models. Our findings indicate that anti-DLL4 ADCs have promising potential as an effective therapy for breast cancer.

Depleted tumor suppressor miR-107 in plasma relates to tumor progression and is a novel therapeutic target in pancreatic cancer. Sci Rep. 2017;7:5708. [PMID: 28720759 PMCID: PMC5515843 DOI: 10.1038/s41598-017-06137-8]

This study explored decreased tumor suppressor microRNA (miRNA) plasma levels in pancreatic cancer (PCa) patients to clarify their potential as novel biomarkers and therapeutic targets. We used the microRNA array-based approach to select candidates by comparing plasma levels between PCa patients and healthy volunteers. Six down-regulated miRNAs (miR-107, miR-126, miR-451, miR-145, miR-491-5p, and miR-146b-5p) were selected. Small- and large-scale analyses using samples from 100 PCa patients and 80 healthy volunteers revealed that miR-107 was the most down-regulated miRNA in PCa patients compared with healthy volunteers (P < 0.0001; area under the receiver-operating characteristic curve, 0.851). A low miR-107 plasma level was significantly associated with advanced T stage, N stage, and liver metastasis and was an independent factor predicting poor prognosis in PCa patients (P = 0.0424; hazard ratio, 2.95). miR-107 overexpression in PCa cells induced G1/S arrest with the production of p21 and inhibited cell proliferation through the transcriptional regulation of Notch2. In vivo, the restoration and maintenance of the miR-107 plasma level significantly inhibited tumor progression in mice. Depletion of the tumor suppressor miR-107 in plasma relates to tumor progression and poor outcomes. The restoration of the plasma miR-107 level might be a novel anticancer treatment strategy for PCa.

Pancreatic Ductal Adenocarcinoma: Current and Evolving Therapies

Pancreatic ductal adenocarcinoma (PDAC), which constitutes 90% of pancreatic cancers, is the fourth leading cause of cancer-related deaths in the world. Due to the broad heterogeneity of genetic mutations and dense stromal environment, PDAC belongs to one of the most chemoresistant cancers. Most of the available treatments are palliative, with the objective of relieving disease-related symptoms and prolonging survival. Currently, available therapeutic options are surgery, radiation, chemotherapy, immunotherapy, and use of targeted drugs. However, thus far, therapies targeting cancer-associated molecular pathways have not given satisfactory results; this is due in part to the rapid upregulation of compensatory alternative pathways as well as dense desmoplastic reaction. In this review, we summarize currently available therapies and clinical trials, directed towards a plethora of pathways and components dysregulated during PDAC carcinogenesis. Emerging trends towards targeted therapies as the most promising approach will also be discussed.

Jagged-2 (JAG2) enhances tumorigenicity and chemoresistance of colorectal cancer cells

Colorectal cancer (CRC) is one of the leading causes of cancer-related mortality. Recent studies have stated that NOTCH signaling plays an important role in the development and progression of CRC. However, the role of Jagged-2 (JAG2), one of the NOTCH ligands, has not been delineated in colorectal tumorigenesis and drug resistance. In the present study, we have examined the impact of targeting JAG2 on CRC cells. Among all the members of NOTCH ligands, only the expression of JAG2 was found up-regulated in the intestinal tumors of Apc ^Min /+ mice as compared to the nearby normal mucosa. JAG2 expression was also observed in a panel of human CRC cell lines. Pharmacological inhibition or genetic knockdown of β-catenin in CRC cell lines suppressed JAG2 expression, suggesting Wnt/β-catenin regulation of JAG2 expression. In addition, deletion of Apc gene in the intestinal cells of Apc conditional knockout mice resulted in up-regulation of JAG2 expression. Modulation of JAG2 expression significantly affected in vivo tumorigenicity of CRC cell lines. Moreover, knockdown of JAG2 sensitized CRC cells to chemotherapeutic agents, while ectopic expression of JAG2 increased chemoresistance of the CRC cells. Significant down-regulation of p21 was observed in JAG2-knockdown cells. Forced expression of p21 rescued the sensitivity of JAG2-knockdown cells to doxorubicin. In addition, the chemosensitivity of p21-null cells was not affected by JAG2 knockdown. These results suggest that JAG2 modulates the sensitivity of CRC cells to chemotherapeutic agents through p21. Our study identifies JAG2 as a novel target for therapeutic intervention of CRC.

tRF/miR-1280 Suppresses Stem Cell-like Cells and Metastasis in Colorectal Cancer

Several studies have shown that tRNAs can be enzymatically cleaved to generate distinct classes of tRNA-derived fragments (tRF). Here, we report that tRF/miR-1280, a 17-bp fragment derived from tRNA^Leu and pre-miRNA, influences Notch signaling pathways that support the function of cancer stem-like cells (CSC) in colorectal cancer progression. tRF/miR-1280 expression was decreased in human specimens of colorectal cancer. Ectopic expression of tRF/miR-1280 reduced cell proliferation and colony formation, whereas its suppression reversed these effects. Mechanistic investigations implicated the Notch ligand JAG2 as a direct target of tRF/miR-1280 binding through which it reduced tumor formation and metastasis. Notably, tRF/miR-1280-mediated inactivation of Notch signaling suppressed CSC phenotypes, including by direct transcriptional repression of the Gata1/3 and miR-200b genes. These results were consistent with findings of decreased levels of miR-200b and elevated levels of JAG2, Gata1, Gata3, Zeb1, and Suz12 in colorectal cancer tissue specimens. Taken together, our results established that tRF/miR-1280 suppresses colorectal cancer growth and metastasis by repressing Notch signaling pathways that support CSC phenotypes. Furthermore, they provide evidence that functionally active miRNA can be derived from tRNA, offering potential biomarker and therapeutic uses. Cancer Res; 77(12); 3194-206. ©2017 AACR.