Elevated DLL4 expression is correlated with VEGF and predicts poor prognosis of nasopharyngeal carcinoma

The Prediction of DLL4 as a Prognostic Biomarker in Patients with Gastric Cancer Using Anti-DLL4 Nanobody

BACKGROUND

Angiogenesis and cancer metastasis depend on the DLL4/Notch signaling pathway. A new approach to treating angiogenesis could inhibit or block this pathway. In the present study, we investigated DLL4 expression as a biomarker capable of predicting survival outcomes in gastric cancer patients using a novel anti-DLL4 Nanobody.

PATIENTS AND METHODS

By using a recently developed anti-DLL4 Nanobody, the expression of DLL4 was evaluated in tissue samples from 135 gastric cancer patients. It was evaluated whether DLL4 expression is related to clinicopathological factors, overall survival (OS), and recurrence-free survival (RFS).

RESULTS

Sixty-five (48%) gastric cancer patients had a positive expression of DLL4 within the tumor tissue. Based on both the univariate and multivariate regression analyses, the expression of DLL4 was strongly associated with RFS (HR, 1.94; p = 0.008) and OS (HR, 2.06; p = 0.004). Moreover, the survival analysis demonstrated that DLL4 expression was a significant independent factor of unfavorable OS (HR, 2.7; p = 0.01) and RFS (HR, 2.3; p = 0.02) in gastric cancer patients.

CONCLUSION

DLL4 expression in gastric cancer patients may predict poor prognosis and survival. Furthermore, the current data demonstrate the potential of Nanobody for detecting DLL4, and it may lead to develop novel therapies and diagnostics for tumors.

Assessing angiogenesis factors as prognostic biomarkers in breast cancer patients and their association with clinicopathological factors

INTRODUCTION

Angiogenesis is fundamental for tumor growth and metastasis across many solid malignancies. Considerable interest has focused on the molecular regulation of tumor angiogenesis as a means to predict disease outcomes and guide therapeutic decisions.

METHODS

In the present study, we investigated the prognostic value of transforming growth factor beta (TGF-β), epidermal growth factor (EGF), fibroblast growth factor (FGF), delta-like ligand 4 (DLL4), and vascular endothelial growth factor (VEGF) in the serum of 120 women diagnosed with breast cancer using ELISA as well as examined their associations with clinical parameters and the outcome of the disease.

RESULTS

Our results demonstrated that the serum concentration of TGF-β and EGF were remarkably higher in patients with higher tumor size, end stages of the disease, and positive lymph node involvement compared to patients with lower tumor size, early stages of the disease, and negative lymph node involvement. In addition, we found a significant correlation between the serum concentration of VEGF and the level of EGF, FGF, and DLL4 in patients with breast cancer. Furthermore, both univariate and multivariate analyses showed that TGF-β and EGF can be used as end-stage predictors.

DISCUSSION/CONCLUSION

Based on our findings, increasing the level of angiogenesis factors is significantly associated with higher tumor size and late stages of the disease in patients with breast cancer. Moreover, measuring the level of angiogenesis factors could lead to better prediction of disease outcomes and choosing the best treatments for patients.

Low HES-1 and positive DLL4 expression predicts poor prognosis of colorectal cancers

Hairy and enhancer of split-1 (HES-1) is a downstream transcription factor and delta-like 4 (DLL4) is a ligand of the Notch signalling pathway. HES-1 and DLL4 expression are known to have an association with the progression and metastasis of cancers. We evaluated HES-1 and DLL4 expression and assessed their correlation with biological behaviour and prognostic significance of 327 colorectal cancers. Low HES-1 expression was identified in 210 (64.2%) cases and was significantly correlated with large tumour size, lymphovascular invasion, and distant metastasis. DLL4 was positive in 132 (40.4%) cases and significantly correlated with perineural invasion, distant metastasis, and involved resection margin. Patients with low HES-1 expression showed significantly worse overall survival than patients with high HES-1 expression [hazard ratio (HR)=3.017; 95% confidence interval (CI) 1.880-4.841; p<0.001]. The overall survival of patients with positive DLL4 expression was significantly worse than that of patients with negative DLL4 expression (HR=2.922; 95% CI 1.976-4.322; p<0.001). Furthermore, the combined HES-1^lowDLL4^positive expression group showed the worst overall survival compared to other groups (p<0.001) and was an independent poor prognostic factor of colorectal cancer patients. Thus, low HES-1 and positive DLL4 expression are associated with aggressive biological behaviour and can be used as prognostic factors in colorectal cancer patients.

Prognostic Index for Nonsmall Cell Lung Cancer Based on Immune-Related Genes Expression

Immune system dysregulation is associated with tumor incidence and growth. Here, we established an RNA-based individualized immune signature associated with prognosis for nonsmall cell lung cancer (NSCLC) to guide adjuvant therapy. We downloaded publicly accessible data on RNA expression and clinical characteristics of NSCLC from the Cancer Genome Atlas (TCGA). From immune-related genes (IRGs) retrieved from the immunology database and analysis portal (ImmPort) database, we then screened differentially expressed immune-related genes (DEIRGs). Using overall survival (OS) as a clinical endpoint, we identified 26 prognostic DEIRGs via univariate and multivariate Cox regression analysis, and then developed a risk model based on these 26 IRGs with an area under the curve (AUC) of 0.701, and its predictive ability independent from other clinical factors. We also downloaded tumor immune infiltrate data and analyzed the correlations between lymphocytic infiltration with our risk scores, but found no significant association. Furthermore, we retrieved 86 differentially expressed transcription factors (TFs) to assess their regulatory relationships with the 26 prognostic DEIRGs. In summary, we developed a robust risk model to predict survival in patients with NSCLC, based on the expression of 26 IRGs. It provides novel predictive and therapeutic molecular targets.

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.

Prognostic Biomarkers for Survival in Nasopharyngeal Carcinoma: A Systematic Review of the Literature

This systematic review aims to identify prognostic molecular biomarkers which demonstrate strong evidence and a low risk of bias in predicting the survival of nasopharyngeal carcinoma (NPC) patients. The literature was searched for on PubMed to identify original clinical studies and meta-analyses which reported associations between molecular biomarkers and survival, including ≥150 patients with a survival analysis, and the results were validated in at least one independent cohort, while meta-analyses must include ≥1000 patients with a survival analysis. Seventeen studies fulfilled these criteria-two studies on single nucleotide polymorphisms (SNPs), three studies on methylation biomarkers, two studies on microRNA biomarkers, one study on mutational signature, six studies on gene expression panels, and three meta-analyses on gene expressions. The comparison between the hazard ratios of high-risk and low-risk patients along with a multivariate analysis are used to indicate that these biomarkers have significant independent prognostic values for survival. The biomarkers also indicate a response to certain treatments and whether they could be used as therapeutic targets. This review highlights that patients' genetics, epigenetics, and signatures of cancer and immune cells in the tumor microenvironment (TME) play a vital role in determining their survival.

Repeated intravitreal ranibizumab for reactivated retinopathy of prematurity after intravitreal ranibizumab monotherapy: vascular development analysis

PURPOSE

To evaluate the retinal vascularization of repeated intravitreal ranibizumab (IVR) for reactivated retinopathy of prematurity (ROP) treated with IVR monotherapy.

METHODS

The retrospective study reviewed ROP infants who accepted IVR injection as the first treatment in our department from January 2017 to December 2018. The ratio of the distance from the center of the optic disc to the border of the vascularized zone (DB) to the distance from the center of the disc to the fovea (DF) was used for the vascular outgrowth analysis.

RESULTS

Seventy-eight infants were included in the study. A total of 54.3% of the reactivated ROP patients could achieve complete vascularization after repeated IVR injections. Gestational age (GA) > 29 weeks and a temporal DB/DF ratio ≥ 3 in the first IVR were potential predictors for complete retinal vascularization after IVR monotherapy. The temporal DB/DF ratio ≥ 3.6 in the second IVR injection was a potential predictor for complete retinal vascularization after repeated IVR for ROP reactivation.

CONCLUSIONS

Reactivated ROP after IVR monotherapy can be treated successfully with repeated IVR injections. GA and temporal DB/DF ratio are potential predictors of complete retinal vascularization in ROP infants treated with IVR.

Delta-like ligand 4 level in colorectal cancer is associated with tumor aggressiveness, body mass index and clinical outcome

BACKGROUND

The Notch signaling regulates numerous cell growth, differentiation, and death. However, the expression pattern of its ligand Delta-like 4 (DLL4) in tumors is still uncertain.

OBJECTIVE

In the present study, we examined DLL4 expression in colorectal cancer as well as assessed its role as a prognostic indicator in the present study.

METHODS

DLL4 expression was examined by immunohistochemistry in 265 surgically resected specimens of colorectal cancer and adjacent normal tissues. The relationship between DLL4 expression and clinicopathological characteristics was analyzed. The association of DLL4 expression with the patients' overall survival rate was assessed by Kaplan-Meier and Cox proportional-hazards regression.

RESULTS

Increased DLL4 level was detected in colorectal cancer compared with that of normal tissues. Elevated DLL4 level in colorectal cancer was associated with increased body mass index of patients. Moreover, increased DLL4 level was also found to be correlated with tumor invasion, metastases and unfavorable clinical outcom of patients.

CONCLUSIONS

DLL4 level is increased in colorectal cancer, especially in patients with increased body mass index, indicating potential involvement of obesity-related tumorigenesis and development. It might also serve as a novel molecular marker to predicate outcome of patients.

A Prognostic Model of 15 Immune-Related Gene Pairs Associated With Tumor Mutation Burden for Hepatocellular Carcinoma

Introduction

Tumor mutation burden (TMB) is an emerging biomarker for immunotherapy of hepatocellular carcinoma (HCC), but its value for clinical application has not been fully revealed.

Materials and Methods

We used the Wilcox test to identify the differentially expressed immune-related genes (DEIRGs) in groups with high and low TMB as well as screened the immune gene pairs related to prognosis using univariate Cox regression analysis. A LASSO Cox regression prognostic model was developed by combining The Cancer Genome Atlas Liver Hepatocellular Carcinoma (TCGA-LIHC) with the International Cancer Genome Consortium (ICGC) LIRI-JP cohort, and internal (TCGA, ICGC) and external (GSE14520) validation analyses were conducted on the predictive value of the model. We also explored the relationship between the prognostic model and tumor microenvironment via the ESTIMATE algorithm and performed clinical correlation analysis by the chi-square test, revealing its underlying molecular mechanism with the help of Gene Set Enrichment Analysis (GSEA).

Results

The prognostic model consisting of 15 immune gene pairs showed high predictive value for short- and long-term survival of HCC in three independent cohorts. Based on univariate multivariate Cox regression analysis, the prognostic model could be used to independently predict the prognosis in each independent cohort. The immune score, stromal score, and estimated score values were lower in the high-risk group than in the low-risk group. As shown by the chi-square test, the prognostic model exhibited an obvious correlation with the tumor stage [American Joint Committee on Cancer tumor–node–metastasis (AJCC-TNM) (p < 0.001), Barcelona Clinic Liver Cancer (BCLC) (p = 0.003)], histopathological grade (p = 0.033), vascular invasion (p = 0.009), maximum tumor diameter (p = 0.013), and background of liver cirrhosis (p < 0.001). GSEA revealed that the high-risk group had an enrichment of many oncology features, including the cell cycle, mismatch repair, DNA replication, RNA degradation, etc.

Conclusion

Our research developed and validated a reliable prognostic model associated with TMB for HCC, which may help to further enrich the therapeutic targets of HCC.

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.

Heritable modifiers of the tumor microenvironment influence nanoparticle uptake, distribution and response to photothermal therapy

We report the impact of notch-DLL4-based hereditary vascular heterogeneities on the enhanced permeation and retention (EPR) effect and plasmonic photothermal therapy response in tumors. Methods: We generated two consomic rat strains with differing DLL4 expression on 3rd chromosome. These strains were based on immunocompromised Salt-sensitive or SSIL2Rγ- (DLL4-high) and SS.BN3IL2Rγ- (DLL4-low) rats with 3rd chromosome substituted from Brown Norway rat. We further constructed three novel SS.BN3IL2Rγ- congenic strains by introgressing varying segments of BN chromosome 3 into the parental SSIL2Rγ- strain to localize the role of SSIL2Rγ- DLL4 on tumor EPR effect with precision. We synthesized multimodal theranostic nanoparticles (TNPs) based on Au-nanorods which provide magnetic resonance imaging (MRI), X-ray, and optical contrasts to assess image guided PTT response and quantify host specific therapy response differences in tumors orthotopically xenografted in DLL4-high and -low strains. We tested recovery of therapy sensitivity of PTT resistant strains by employing anti-DLL4 conjugated TNPs in two triple negative breast cancer tumor xenografts. Results: Host strains with high DLL4 allele demonstrated slightly increased tumor nanoparticle uptake but consistently developed photothermal therapy resistance compared to tumors in host strains with low DLL4 allele. Tumor micro-environment with low DLL4 expression altered the geographic distribution of nanoparticles towards closer proximity with vasculature which improved efficacy of PTT in spite of lower overall TNP uptake. Targeting TNPs to tumor endothelium via anti-DLL4 antibody conjugation improved therapy sensitivity in high DLL4 allele hosts for two triple negative human breast cancer xenografts. Conclusions: Inherited DLL4 expression modulates EPR effects in tumors, and molecular targeting of endothelial DLL4 via nanoparticles is an effective personalized nanomedicine strategy.

The PERK Branch of the Unfolded Protein Response Promotes DLL4 Expression by Activating an Alternative Translation Mechanism

Delta-like 4 (DLL4) is a pivotal endothelium specific Notch ligand that has been shown to function as a regulating factor during physiological and pathological angiogenesis. DLL4 functions as a negative regulator of angiogenic branching and sprouting. Interestingly, Dll4 is with Vegf-a one of the few examples of haplo-insufficiency, resulting in obvious vascular abnormalities and in embryonic lethality. These striking phenotypes are a proof of concept of the crucial role played by the bioavailability of VEGF and DLL4 during vessel patterning and that there must be a very fine-tuning of DLL4 expression level. However, to date the expression regulation of this factor was poorly studied. In this study, we showed that the DLL4 5′-UTR harbors an Internal Ribosomal Entry Site (IRES) that, in contrast to cap-dependent translation, was efficiently utilized in cells subjected to several stresses including hypoxia and endoplasmic reticulum stress (ER stress). We identified PERK, a kinase activated by ER stress, as the driver of DLL4 IRES-mediated translation, and hnRNP-A1 as an IRES-Trans-Acting Factor (ITAF) participating in the IRES-dependent translation of DLL4 during endoplasmic reticulum stress. The presence of a stress responsive internal ribosome entry site in the DLL4 msRNA suggests that the process of alternative translation initiation, by controlling the expression of this factor, could have a crucial role in the control of endothelial tip cell function.

Concurrent Treatment with Anti-DLL4 Enhances Antitumor and Proapoptotic Efficacy of a γ-Secretase Inhibitor in Gastric Cancer

The Notch signaling pathway has been identified as a therapeutic target for cancers. γ-Secretase inhibitors (GSIs) have been progressively recognized as potential anticancer drugs. The present study aimed to investigate the effects of anti-delta like legend 4 (anti-DLL4) treatment on the anticancer efficacy of GSIs in gastric cancer. SGC-7901-GFP human gastric cancer cells were tested for DLL4 expression by rosette formation test and immunofluorescence, and then were treated with anti-DLL4 antibody N-[N-(3,5-difluorophenacetyl)-L-ananyl]-S-phenylglycine t-butyl ester (DAPT, a type of GSI), or a combination of anti-DLL4 antibody and DAPT. The effects of in vitro treatments on cell apoptosis, cell cycle, and cell invasion were analyzed. For in vivo study, an orthotopic mouse model of gastric cancer was established with green fluorescence expressing SGC-7901. Ultrasound targeted microbubble destruction was used to treat tumor-bearing mice with anti-DLL4 antibody conjugated microbubbles, DAPT, and a combination of the two. Real-time fluorescence imaging was performed to assess tumor cell inhibition in each group. Following in vivo treatments, apoptosis of tumor cells and the expression of apoptosis-related genes BAX, Bcl-2, and P53 were detected by TUNEL and immunohistochemical staining. In vivo combined treatment of anti-DLL4 and DAPT led to a higher rate of cell apoptosis and greater inhibition of cell invasion than that observed with DAPT treatment alone. DAPT and anti-DLL4 combination therapy resulted in decreased cell distribution at G1 phase and increased cell distribution at S phase, compared to the untreated control group (P < .01). In vivo combined therapy with anti-DLL4 and DAPT significantly increased tumor growth inhibition and tumor cell apoptosis when compared to DAPT therapy alone (P < .05). In addition, combined treatment significantly increased expression of BAX and P53 and reduced Bcl-2 expression (P < .05). Conversely, treatment with DAPT alone only increased expression of BAX and P53 (P < .05), suggesting that the reduction of Bcl-2 expression may play an important role in the synergetic antitumor and proapoptosis effects of the combined treatment. Concurrent treatment with anti-DLL4 enhances the antitumor and proapoptotic efficacy of the γ-secretase inhibitor in gastric cancer both in vitro and in vivo.

The NOTCH Pathway in Head and Neck Squamous Cell Carcinoma

Comprehensive genomic analyses have been performed for head and neck squamous cell carcinoma (HNSCC), revealing a significant rate of NOTCH1 mutations and identifying NOTCH1 as the second most frequently mutated gene after TP53. Most NOTCH1 mutations are considered inactivating, indicating that NOTCH1 is a tumor suppressor gene. On the other hand, cohorts from Asian populations with HNSCC have shown activating NOTCH1 mutations. HNSCC with NOTCH1 mutations have a worse prognosis than the NOTCH1 wild-type tumors. Additional data on other NOTCH family members have shown that NOTCH promotes HNSCC progression. NOTCH family members, including NOTCH pathway genes, are upregulated in HNSCC compared with normal tissues, and inhibition of the NOTCH pathway decreases cell proliferation and invasion. NOTCH activity in HNSCC is therefore contextual, and NOTCH in HNSCC is considered to have a bimodal role as a tumor suppressor and an oncogene. In this review, recent understandings of NOTCH pathway genes, including NOTCH genes, in HNSCC are described. In addition, the implications of NOTCH pathway alteration for HNSCC-specific NOTCH-targeted cancer therapy are explored.

A large-scale retrospective study of the overall survival outcome in nasopharyngeal carcinoma with hypertension in Chinese population

BACKGROUND

It is known that hypertension is associated with high levels of vascular endothelial growth factor (VEGF) expression which is, in turn, highly connected to the prognosis of a wide array of cancers. The purpose of this study was to evaluate the relationship between hypertension and prognosis of nasopharyngeal carcinoma (NPC) with definitive radiotherapy in a Chinese population.

PATIENTS AND METHODS

We retrospectively reviewed 4493 patients with NPC who received definitive radiotherapy from 1995 to 2006, with a minimum follow-up of 5 years. Kaplan-Meier survival analysis and Cox proportional hazard model were utilized to determine the association between hypertension and overall survival (OS).

RESULTS

A total of 802 patients with NPC suffered from hypertension as compared to 3691 patients with no associated hypertension. Kaplan-Meier analysis revealed median overall survival of 101.1 and 110.0 months, respectively (p<0.05). In univariate survival analysis, patients with hypertension had worse OS (p<0.05) than non-hypertension patients. Patients with higher grade hypertension also had worse OS (p<0.05) compare to patients with grade 1 hypertension. In multivariate survival analysis, patients with hypertension had significantly worse OS (p<0.05) than non-hypertension patients, as well as M stage (p<0.001), after adjustment for related clinical confounding factors.

CONCLUSION

Our findings provide evidence that hypertension is an independent factor and result in poorer survival outcomes in patients with NPC, the mechanism is still unclear, and it worth further research.

Cyclooxygenase-2 expression is positively associated with lymph node metastasis in nasopharyngeal carcinoma

BACKGROUND

Accumulating evidence has demonstrated that cyclooxygenase-2 (COX-2) is involved in head and neck cancers, especially in nasopharyngeal carcinoma (NPC). However, the association between COX-2 expression and lymph node metastasis in NPC remains uncertain. This systematic review and meta-analysis meta-analysis investigated the relationship between COX-2 expression and lymph node metastasis and other signs of disease progression in NPC.

METHODS

Previously published studies assessing COX-2 expression and lymph node metastasis in NPC were identified in four English databases and three Chinese ones (Pubmed, Embase, Cochrane Database of Systematic Reviews, Web of Science, China National Knowledge Infrastructure, Wanfang, Vip Journal Integration Platform) up to November 2016. Quality of all eligible studies was assessed using the Newcastle-Ottawa Quality Assessment Scale (NOS). Pooled odds ratios (OR) and their 95% confidence intervals (95%CI) were calculated with fixed-effects or random-effects model to evaluate the effects of COX-2 expression on lymph node metastasis.

RESULTS

A total of 27 studies with 1797 NPC patients met the inclusion criteria. The expression of COX-2 was significantly higher in patients with nasopharyngeal carcinoma than those without the carcinoma, with a combined OR of 21.17 (95%CI = 15.02-29.85, I2 = 35.1%, Pheterogeneity = 0.070). A statistically significant association between COX-2 expression and lymph node metastasis in NPC patients, with an OR of 4.44 (95%CI = 3.46-5.70, I2 = 38.3%, Pheterogeneity = 0.024), and with other indicators of disease progression. Subgroup analyses based on COX-2 assay and staging criteria of TNM showed no significant heterogeneity.

CONCLUSIONS

The results suggest that expression of COX-2 is associated with lymph node metastasis and disease progression in NPC, indicating a potential role in evaluation of prognosis and in treatment decisions. COX-2 inhibitors have potential in the treatment of NPC that should be further investigated.

Minicircle-oriP-miR-31 as a Novel EBNA1-Specific miRNA Therapy Approach for Nasopharyngeal Carcinoma

MicroRNAs (miRNAs) are important post-transcriptional regulators that control cancer development and progression. However, the application of miRNA therapy in cancer has been hampered by a lack of an efficient and targeted delivery system. In our previous studies, an oriP promoter-based minicircle system successfully mediated targeted foreign gene expression in EBNA1-positive nasopharyngeal carcinoma (NPC). However, it remains to be evaluated whether this system can be applied for tumor miRNA therapy. miR-31-5p, a tumor suppressive miRNA involved in the tumorigenesis of EBV-positive NPC, was selected as the therapeutic miRNA to be transferred. In this work, we constructed a novel EBNA1-specific miRNA expression system, minicircle-oriP-miR-31. The results indicated that mc-oriP-miR-31 mediated selective miR-31-5p expression in EBNA1-positive NPC cells. Both the proliferation and migration of EBNA1-positive NPC cell lines were inhibited by mc-oriP-miR-31 treatment in vitro. Furthermore, mc-oriP-miR-31 treatment inhibited xenograft growth and lung metastasis in vivo. We also identified WDR5 as a novel miR-31-5p target. Knockdown of WDR5 inhibited NPC cell proliferation and migration and was associated with downregulation of Notch1. Reintroduction of WDR5 partially abrogated the suppressive effects induced by miR-31-5p. In conclusion, we demonstrate for the first time that targeted expression of miR-31-5p using a nonviral minicircle vector can serve as a novel approach for tumor miRNA therapy. Moreover, WDR5 may be a promising therapeutic target for NPC treatment.

DLL4 overexpression increases gastric cancer stem/progenitor cell self-renewal ability and correlates with poor clinical outcome via Notch-1 signaling pathway activation

Gastric cancer is one of the most common malignant diseases, and poses a serious threat to the quality of human life. Gastric cancer stem/progenitor cells (GCSPCs) have critical effects on tumor formation, affecting specific features of self‐renewal and differentiation and playing a critical role in metastasis. The Notch‐1 pathway is crucially important to GCSPCs and is regulated by DLL4. In this study, DLL4 and Nestin levels were measured in 383 gastric cancer tissue samples by immunohistochemistry, and the clinico‐pathological features of patients assessed. After DLL4 silencing in selected gastric cancer cell lines, the expression of GCSPC markers and colony formation ability were analyzed and the self‐renewal and differentiation capacities of the cells were evaluated. The relationship between DLL4 levels and Notch‐1 signaling pathway effector amounts was assessed via Western blotting and immunofluorescence. Finally, the tumor formation ability of the gastric cancer cells was evaluated with different levels of DLL4 and multiple cell densities in vivo. Our results indicate that DLL4 expression is associated with TNM stage and cancer metastasis, with high amounts of DLL4 leading to poor outcome. DLL4 silencing inhibited the self‐renewal ability of GCSPCs and increased their multidifferentiation capacity, resulting in reduced GCSPC ratios. DLL4 knockdown also blocked the Notch‐1 pathway, weakening invasion ability and resistance to 5‐FU chemotherapy. In vivo, DLL4 silencing inhibited the tumor formation ability of GCSPCs. In conclusion, DLL4 affects GCSPC stemness, altering their pathological behavior. DLL4 silencing inhibits GCSPC metastatic potential both in vitro and in vivo by impeding Notch‐1 signaling pathway activation, indicating that DLL4 may be a new potential therapeutic target.

PTPRG suppresses tumor growth and invasion via inhibition of Akt signaling in nasopharyngeal carcinoma

Protein Tyrosine Phosphatase, Receptor Type G (PTPRG) was identified as a candidate tumor suppressor gene in nasopharyngeal carcinoma (NPC). PTPRG induces significant in vivo tumor suppression in NPC. We identified EGFR as a PTPRG potential interacting partner and examined this interaction. Dephosphorylation of EGFR at EGFR-Y1068 and -Y1086 sites inactivated the PI3K/Akt signaling cascade and subsequent down-regulation of downstream pro-angiogenic and -invasive proteins (VEGF, IL6, and IL8) and suppressed tumor cell proliferation, angiogenesis, and invasion. The effect of Akt inhibition in NPC cells was further validated by Akt knockdown experiments in the PTPRG-down-regulated NPC cell lines. Our results suggested that inhibition of Akt in NPC cells induces tumor suppression at both the in vitro and in vivo levels, and also importantly, in vivo metastasis. In conclusion, we confirmed the vital role of PTPRG in inhibiting Akt signaling with the resultant suppression of in vivo tumorigenesis and metastasis.

DLL4 as a predictor of pelvic lymph node metastasis and a novel prognostic biomarker in patients with early-stage cervical cancer

Delta-like ligand 4 (DLL4), one of the five Notch signaling ligands in mammals, has an important function in proliferation, invasion, metastasis, progression, and angiogenesis of malignancies. This study aimed to investigate DLL4 expression level in early-stage cervical carcinoma and to evaluate its clinical significance. We used fresh frozen and paraffin-embedded cervical cancer tissues to analyze DLL4 expression and its clinical significance. DLL4 expression at both mRNA and protein levels in cervical cancer tissues was significantly higher than that in normal cervical tissues. High DLL4 protein level was clearly correlated with high International Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.044), lymphovascular space involvement (LVSI) (P = 0.015), pelvic lymph node metastasis (PLNM) (P = 0.001), and recurrence (P < 0.001). Univariate and multivariate logistic regression analyses demonstrated that DLL4 overexpression was strongly associated with lymph node metastasis (odds ratio, 2.790; 95 % CI, 1.344-5.791; P = 0.006). Moreover, survival analysis revealed that DLL4 expression was an independent factor of unfavorable overall survival (hazard ratio, 2.130; 95 % CI, 1.108-4.097; P = 0.023) and disease-free survival (hazard ratio, 1.965; 95 % CI, 1.085-3.560; P = 0.026) in patients with cervical cancer. Overall, our data indicate that high DLL4 expression predicts pelvic lymph node metastasis and poor survival in cervical cancer. Therefore, DLL4 may be a potential clinical diagnostic marker for patients with early-stage cervical cancer.

PET Imaging of Dll4 Expression in Glioblastoma and Colorectal Cancer Xenografts Using (64)Cu-Labeled Monoclonal Antibody 61B

Delta-like ligand 4 (Dll4) expressed in tumor cells plays a key role to promote tumor growth of numerous cancer types. Based on a novel antihuman Dll4 monoclonal antibody (61B), we developed a (64)Cu-labeled probe for positron emission tomography (PET) imaging of tumor Dll4 expression. In this study, 61B was conjugated with the (64)Cu-chelator DOTA through lysine on the antibody. Human IgG (hIgG)-DOTA, which did not bind to Dll4, was also prepared as a control. The Dll4 binding activity of the probes was evaluated through the bead-based binding assay with Dll4-alkaline phosphatase. The resulting PET probes were evaluated in U87MG glioblastoma and HT29 colorectal cancer xenografts in athymic nude mice. Our results demonstrated that the 61B-DOTA retained (77.2 ± 3.7) % Dll4 binding activity of the unmodified 61B, which is significantly higher than that of hIgG-DOTA (0.06 ± 0.03) %. Confocal microscopy analysis confirmed that 61B-Cy5.5, but not IgG-Cy5.5, predominantly located within the U87MG and HT29 cells cytoplasm. U87MG cells showed higher 61B-Cy5.5 binding as compared to HT29 cells. In U87MG xenografts, 61B-DOTA-(64)Cu demonstrated remarkable tumor accumulation (10.5 ± 1.7 and 10.2 ± 1.2%ID/g at 24 and 48 h postinjection, respectively). In HT29 xenografts, tumor accumulation of 61B-DOTA-(64)Cu was significantly lower than that of U87MG (7.3 ± 1.3 and 6.6 ± 1.3%ID/g at 24 and 48 h postinjection, respectively). The tumor accumulation of 61B-DOTA-(64)Cu was significantly higher than that of hIgG-DOTA-(64)Cu in both xenografts models. Immunofluorescence staining of the tumor tissues further confirmed that tumor accumulation of 61B-Cy5.5 was correlated well with in vivo PET imaging data using 61B-DOTA-(64)Cu. In conclusion, 61B-DOTA-(64)Cu PET probe was successfully synthesized and demonstrated prominent tumor uptake by targeting Dll4. 61B-DOTA-(64)Cu has great potential to be used for noninvasive Dll4 imaging, which could be valuable for tumor detection, Dll4 expression level evaluation, and Dll4-based treatment monitoring.

Incomplete Dll4/Notch signaling inhibition promotes functional angiogenesis supporting the growth of skin papillomas

BACKGROUND

In invasive malignancies, Dll4/Notch signaling inhibition enhances non-functional vessel proliferation and limits tumor growth by reducing its blood perfusion.

METHODS

To assess the effects of targeted Dll4 allelic deletion in the incipient stages of tumor pathogenesis, we chemically induced skin papillomas in wild-type and Dll4 (+/-) littermates, and compared tumor growth, their histological features, vascularization and the expression of angiogenesis-related molecules.

RESULTS

We observed that Dll4 down-regulation promotes productive angiogenesis, although with less mature vessels, in chemically-induced pre-cancerous skin papillomas stimulating their growth. The increase in endothelial activation was associated with an increase in the VEGFR2 to VEGFR1 ratio, which neutralized the tumor-suppressive effect of VEGFR-targeting sorafenib. Thus, in early papillomas, lower levels of Dll4 increase vascularization through raised VEGFR2 levels, enhancing sensitivity to endogenous levels of VEGF, promoting functional angiogenesis and tumor growth.

CONCLUSION

Tumor promoting effect of low-dosage inhibition needs to be considered when implementing Dll4 targeting therapies.

A Phase I First-in-Human Study of Enoticumab (REGN421), a Fully Human Delta-like Ligand 4 (Dll4) Monoclonal Antibody in Patients with Advanced Solid Tumors

PURPOSE

Enoticumab (REGN421) is a fully human IgG1 monoclonal antibody that binds human Dll4 and disrupts Notch-mediated signaling. The main objectives of this trial were to determine the safety, dose-limiting toxicities (DLT), pharmacokinetics (PK), and recommended phase II dose (RP2D) of enoticumab.

EXPERIMENTAL DESIGN

Enoticumab was administered intravenously, with dose escalations from 0.25 to 4 mg/kg every 3 weeks (Q3W) and 0.75 to 3 mg/kg every 2 weeks (Q2W).

RESULTS

Of 53 enrolled patients, 31 patients were treated Q3W and 22 patients were treated Q2W. Two DLTs occurred: grade 3 nausea (0.5 mg/kg Q3W) and grade 3 abdominal pain (1 mg/kg Q2W). An MTD was not reached on either schedule. The most frequent adverse events (AE) were fatigue, nausea, vomiting, hypertension, headache, and anorexia. Six treatment-related serious AEs were reported in 4 patients: brain natriuretic peptide (BNP) increase (0.25 mg/kg Q3W, Gr1), troponin I increase (4 mg/kg Q3W, Gr3), right ventricular dysfunction and pulmonary hypertension (1.5 mg/kg Q2W, both Gr3), and left ventricular dysfunction and pulmonary hypertension (3 mg/kg Q2W, both Gr3). Enoticumab was characterized by nonlinear, target-mediated PK, and had a terminal half-life of 8 to 9 days. With multiple Q2W or Q3W dosing, accumulation was not observed. Antitumor activity included two partial responses (non-small cell lung cancer bronchoalveolar-type with a β-catenin mutation, and ovarian cancer) and 16 patients with stable disease (3> 6 months).

CONCLUSIONS

Enoticumab was tolerated, with RP2D of 4 mg/kg Q3W and 3 mg/kg Q2W based on PK profile and clinical activity. Responses and SD were noted in ovarian cancer and other solid tumors. Clin Cancer Res; 21(12); 2695-703. ©2015 AACR.

Dll4 blockade potentiates the anti-tumor effects of VEGF inhibition in renal cell carcinoma patient-derived xenografts

Background

The Notch ligand Delta-like 4 (Dll4) is highly expressed in vascular endothelium and has been shown to play a pivotal role in regulating tumor angiogenesis. Blockade of the Dll4-Notch pathway in preclinical cancer models has been associated with non-productive angiogenesis and reduced tumor growth. Given the cross-talk between the vascular endothelial growth factor (VEGF) and Delta-Notch pathways in tumor angiogenesis, we examined the activity of a function-blocking Dll4 antibody, REGN1035, alone and in combination with anti-VEGF therapy in renal cell carcinoma (RCC).

Methods and Results

Severe combined immunodeficiency (SCID) mice bearing patient-derived clear cell RCC xenografts were treated with REGN1035 and in combination with the multi-targeted tyrosine kinase inhibitor sunitinib or the VEGF blocker ziv-aflibercept. Immunohistochemical and immunofluorescent analyses were carried out, as well as magnetic resonance imaging (MRI) examinations pre and 24 hours and 2 weeks post treatment. Single agent treatment with REGN1035 resulted in significant tumor growth inhibition (36–62%) that was equivalent to or exceeded the single agent anti-tumor activity of the VEGF pathway inhibitors sunitinib (38–54%) and ziv-aflibercept (46%). Importantly, combination treatments with REGN1035 plus VEGF inhibitors resulted in enhanced anti-tumor effects (72–80% growth inhibition), including some tumor regression. Magnetic resonance imaging showed a marked decrease in tumor perfusion in all treatment groups. Interestingly, anti-tumor efficacy of the combination of REGN1035 and ziv-aflibercept was also observed in a sunitinib resistant ccRCC model.

Conclusions

Overall, these findings demonstrate the potent anti-tumor activity of Dll4 blockade in RCC patient-derived tumors and a combination benefit for the simultaneous targeting of the Dll4 and VEGF signaling pathways, highlighting the therapeutic potential of this treatment modality in RCC.

Delta-like ligand 4: A predictor of poor prognosis in clear cell renal cell carcinoma

Delta-like ligand 4 (Dll4)-Notch signaling is important in tumor angiogenesis; however, the prognostic value of D114 detection in patients with clear cell renal cell carcinoma (CCRCC) remains unclear. The present study aimed to determine whether the presence of high Dll4 expression levels was correlated with poor prognosis in CCRCC following curative resection. The D114 expression levels in four paired samples of CCRCC tissues and adjacent normal renal tissues were assayed by western blotting. Surgical specimens comprised 121 CCRCC tissue samples and 65 normal renal tissue samples, obtained from patients with CCRCC. The specimens were immunohistochemically assessed to determine Dll4 and vascular endothelial growth factor receptor 2 (VEGFR-2) expression levels. The prognostic significance of Dll4 expression levels was evaluated by the Kaplan-Meier method and Cox regression analysis. The correlation between Dll4 expression levels and VEGFR-2 expression levels, tumor stage, tumor grade and metastasis, was examined by χ² test and multivariate logistic regression. As determined by the western blotting results, Dll4 protein expression levels were significantly increased in CCRCC tissues compared with those in adjacent non-cancerous tissues. From the analysis of the surgical specimens, 53 (43.8%) CCRCC patients exhibited immunohistochemically high Dll4 expression levels and 68 (56.2%) patients exhibited low Dll4 expression levels. The survival curves revealed that the patients with high Dll4 expression levels had significantly shorter survival times than the patients with low Dll4 expression levels (P<0.001). Multivariate survival analysis demonstrated that the presence of high Dll4 expression levels was independently associated with reduced overall survival and progression-free survival times (P=0.021 and 0.034, respectively). A positive correlation was also identified between Dll4 and VEGFR-2 expression levels (P=0.001). In conclusion, the results show that the presence of high Dll4 expression levels was clearly associated with high VEGFR-2 expression levels, tumor grade, tumor stage and poor prognosis in CCRCC patients. Therefore, inhibition of Dll4 may exert potent growth inhibitory effects on tumors resistant to anti-VEGF therapies for CCRCC.

Aberrant expression of δ-like ligand 4 contributes significantly to axillary lymph node metastasis and predicts postoperative outcome in breast cancer

δ-Like ligand 4 (DLL4), a ligand for the Notch family of receptors, forecasts the prognosis of several human malignancies. However, the expression and role of DLL4 in breast cancer remain largely unknown. In the present study, we first evaluated whether the overexpression of DLL4 could be used as an indicator of axillary lymph node metastasis and postoperative prognosis in breast cancer. The amount of DLL4 protein was assessed in 204 tumor specimens by immunohistochemical staining. Overexpression was detected in 142 (69.6%) and significantly associated with advanced TNM stage (III versus I, P = .031; III versus II, P = .038), axillary lymph node metastasis (P = .001), and postoperative recurrence (P = .007). Moreover, using univariate and multivariate logistic regression analysis, we found that DLL4 overexpression was strongly associated with axillary lymph node metastasis (odds ratio, 3.036; 95% confidence interval [CI], 1.561, 5.902; P = .001). Lastly, survival analysis showed that patients with low DLL4 expression had a significantly better overall survival and disease-free survival than patients with high DLL4 expression. Furthermore, in multivariate analysis, DLL4 overexpression was an independent risk factor for unfavorable overall survival (hazard ratio, 2.662; 95% CI, 1.300, 5.452; P = .007) and disease-free survival (hazard ratio, 2.568; 95% CI, 1.353, 4.876; P = .004). Taken together, these results suggest that high expression of DLL4 is associated with axillary lymph node metastasis and a poor prognosis in breast cancer, suggesting its value as a diagnostic marker for breast cancer.

High delta-like ligand 4 (DLL4) is correlated with peritumoral brain edema and predicts poor prognosis in primary glioblastoma

Delta-like ligand 4 (DLL4), 1 of the 5 known Notch ligands, is involved in a variety of tumor initiation and progression, particularly in the process of tumor angiogenesis. However, the clinical and prognostic significance of DLL4 in glioblastoma have not been fully elucidated.Tumor tissues from 69 glioblastoma patients were analyzed using immunohistochemistry for DLL4 expression. Peritumoral brain edema (PTBE) on preoperative magnetic resonance imaging of these patients and the relationship with DLL4 expression were evaluated. The effect on prognosis was assessed by using the Kaplan-Meier survival and the Cox proportional hazard model.The results showed that elevated DLL4 expression was primarily distributed in the cytoplasm of tumor vascular endothelial cells and rarely detected in tumor cells. Univariate analysis indicated significant correlation of high DLL4 expression with shorter time to progression (TTP) (P < 0.001) and overall survival (OS) (P < 0.001) in glioblastoma. Multivariate analysis confirmed high DLL4 expression as an unfavorable prognostic indicator for TTP (P < 0.001) and OS (P < 0.001), independent of age, gender, symptom duration, resection degree, and PTBE. Importantly, the study also found that DLL4 expression was positively related with PTBE (Spearman's test: r = 0.845, P < 0.001). A multiple linear regression model was constructed to confirm that the positive index of DLL4 was associated with an increase in maximum extent of PTBE (P < 0.001).It is thus concluded that DLL4 is correlated with PTBE and may be useful for predicting prognosis in glioblastoma.

Delta-like ligand 4 (DLL4) in the plasma and neoplastic tissues from breast cancer patients: correlation with metastasis

Delta-like ligand 4 (DLL4) is a ligand of the notch pathway. In tumor angiogenesis, DLL4 switches to vascular maturation by providing a negative feedback on VEGFR2 activity. We investigated the expression of DLL4 in the plasma and cancer tissues from breast cancer patients. Plasma samples were collected from 18 women with localized breast cancer, six women with benign breast disease and from six patients with widespread metastatic disease. DLL4 was assessed using ELISA and in cancer tissues using immunohistochemistry. Patients with metastatic breast cancer had significantly higher levels (median 6.7 ± 0.81 ng/ml) compared to patients with localized tumors (median 5.4 ± 0.70 ng/ml) (p = 0.005) and to patients with benign breast disease (median 4.3 ± 0.28) (p = 0.0003). High histology grade was significantly linked with higher plasma DLL4 levels (median 5.59 ± 0.62 vs. 5.12 ± 0.44 ng/ml; p = 0.01). Surgical removal of high-grade breast cancer resulted in significant reduction in DLL4 plasma levels (p = 0.003). DLL4 was expressed in tumor-associated vessels and in cancer cells. The ratio of DLL4+/CD31+ vascular density (VD) ranged from 23 to 88% (median 49 %). High DLL4 cancer cell expression and high DLL4+ VD were significantly linked with nodal involvement (p = 0.004 and 0.01, respectively). Linear regression analysis showed a significant association of DLL4 plasma levels with the percentage of DLL4+ cancer cells (p = 0.03, r = 0.50) and with DLL4+ VD (p = 0.0007, r = 0.60). It is concluded that DLL4 is overexpressed in breast cancer cells and breast cancer vasculature and is linked with nodal and distant metastasis. DLL4 plasma levels measurement can reliably estimate the total DLL4 breast cancer/vasculature activity.

Epitope mapping of conformational V2-specific anti-HIV human monoclonal antibodies reveals an immunodominant site in V2

In the case-control study of the RV144 vaccine trial, the levels of antibodies to the V1V2 region of the gp120 envelope glycoprotein were found to correlate inversely with risk of HIV infection. This recent demonstration of the potential role of V1V2 as a vaccine target has catapulted this region into the focus of HIV-1 research. We previously described seven human monoclonal antibodies (mAbs) derived from HIV-infected individuals that are directed against conformational epitopes in the V1V2 domain. In this study, using lysates of SF162 pseudoviruses carrying V1V2 mutations, we mapped the epitopes of these seven mAbs. All tested mAbs demonstrated a similar binding pattern in which three mutations (F176A, Y177T, and D180L) abrogated binding of at least six of the seven mAbs to ≤15% of SF162 wildtype binding. Binding of six or all of the mAbs was reduced to ≤50% of wildtype by single substitutions at seven positions (168, 180, 181, 183, 184, 191, and 193), while one change, V181I, increased the binding of all mAbs. When mapped onto a model of V2, our results suggest that the epitope of the conformational V2 mAbs is located mostly in the disordered region of the available crystal structure of V1V2, overlapping and surrounding the α4β7 binding site on V2.