Expression Of Delta-like Ligand Research Articles

Pattern of expression of Delta-like ligand 4 (DLL-4) in patients with pancreatic ductal and ampullary adenocarcinomas and its clinicopathological prognostic implications

There is an increasing interest for Notch signalling pathway and particularly Delta-like ligand 4 (DLL4), a Notch ligand as potential therapeutic target to improve outcome for patients with pancreatic ductal adenocarcinoma (PDAC). : characterize the expression of DLL4 in PDAC and ampullary adenocarcinoma (AA), evaluate their correlation with clinicopathologic features and patients’ survival. In a retrospective study, using immunohistochemistry, we assessed the expression of DLL4 in 62 cases composed of 39 cases of PDAC and 23 cases of AA undergone Whipple and received adjuvant chemotherapy and radiotherapy. We assessed the expression level of DLL4 both in tumor cells and stromal vascular endothelial cells. The relationships of DLL4 expression with clinico-pathologic parameters and clinical outcome were evaluated. There was no statistically significant relation between clinico-pathological parameters and DLL4 score expression in tumor cells of PDAC cases. However, there was statistically significant relation between DLL4 score expression in tumor cells of AA cases and tumor stage (p= 0.041). Also, there was no statistical significance regarding DLL4 expression in stromal cells in PDAC and AA cases and clinico-pathological parameters. Regarding survival functions for pancreatic & ampullary tumor cases; the median overall survival (OS) was 10 and 22 months for pancreatic (95% CI: 1-45) and ampullary tumors (95% CI: 1-69) respectively. OS for pancreatic and ampullary tumors was higher in cases with low DLL4 expression versus cases with high expressions with no statistically significance (P=0.48 & 0.09 respectively). The median Progression free survival (PFS) was 7 and 17.5 months for pancreatic (95% CI: 0-43) and ampullary tumors (95% CI: 0-96) respectively. PFS was higher in cases with low DLL4 expression rather than cases with high expressions with no statistically significant differences (P=0.52 and 0.19 respectively). High DLL4 expression in cancer cells was associated with worse OS and DFS than low DLL4 expression.

In vivo Screening of Natural Products Against Angiogenesis and Mechanisms of Anti-Angiogenic Activity of Deoxysappanone B 7,4'-Dimethyl Ether.

IntroductionThe aim of this study was to screen the leading compounds of natural origin with anti-angiogenic potential and to investigate their anti-angiogenic mechanism preliminarily.Materials and MethodsAn initial screening of 240 compounds from the Natural Products Collection of MicroSource was performed using the transgenic zebrafish strain Tg [fli1a: enhanced green fluorescent protein (EGFP)]y1. The zebrafish embryos at 24 h post-fertilization were exposed to the natural compounds for an additional 24 h; then, morphological changes in the intersegmental vessels (ISVs) were observed and quantified under a fluorescence microscope. The expression profiles of angiogenesis-related genes in the zebrafish embryos were detected using quantitative real-time PCR.ResultsFive compounds were identified with potential anti-angiogenic activity on the zebrafish embryogenesis. Among them, deoxysappanone B 7.4ʹ-dimethyl ether (Deox B 7,4) showed anti-angiogenic activity on the formation of ISVs in a dose-dependent manner. The inhibition of ISV formation reached up to 99.64% at 5 μM Deox B 7,4. The expression of delta-like ligand 4 (dll4), hes-related family basic helix-loop-helix transcription factor with YRPW motif 2, ephrin B2, fibroblast growth factor receptor (fgfr) 3, cyclooxygenase-2, protein tyrosine phosphatase, receptor type B (ptp-rb), phosphoinositide-3-kinase regulatory subunit 2, slit guidance ligand (slit) 2, slit3, roundabout guidance receptor (robo) 1, robo2, and robo4 were down-regulated, while vascular endothelial growth factor receptor-2, fgfr 1, and matrix metallopeptidase 9 were up-regulated in the zebrafish embryos treated with Deox B 7,4.ConclusionDeox B 7,4 has a therapeutic potential for the treatment of angiogenesis-dependent diseases and may exert anti-angiogenic activities by suppressing the slit2/robo1/2, slit3/robo4, cox2/ptp-rb/pik3r2, and dll4/hey2/efnb2a signaling pathways as well as activation of vegfr-2/fgfr1/mmp9.

P097 Depletion of delta-like ligand 4 (Dll4) contributes to the alteration of secretory progenitor differentiation in SAMP1/YitFc mice with Crohn’s disease-like ileitis

Abstract Background When the intestinal epithelium would be exposed to harmful substances, mucosal damage can be occurred and followed by epithelial restoration with regenerative epithelium derived from intestinal stem cells (ISCs). Crohn’s disease (CD) is characterised by chronic mucosal damage and ulceration predominantly involved in the ileum. Thus, we hypothesised that epithelial regeneration in CD might be impaired due to the dysfunction of ileal ISCs or its niche. Methods SAMP1/YitFcsI (SAMP1) mice are recombinant-inbred mice that spontaneously develop ileitis resembling human CD. Alterations in the crypt-villus structure, epithelial differentiation, organoid formation ability, and niche signalling pathways in the ileum of 10- to 14-week-old SAMP1 mice were analysed and compared with age-matched AKR mice. Results In the ileum of SAMP1 mice, the depth of the crypts increased and the surface area of the villi decreased. While the number of ISCs in the ileal crypts did not differ between SAMP1 and AKR mice. The number of Paneth cells decreased and the number of transient amplifying cells increased. The organoid formation ability of the ileal crypts of SAMP1 mice decreased significantly compared with that of AKR mice. RNA-seq revealed a differential gene expression pattern of ileal crypts of SAMP1 mice compared with those of AKR mice. Among the ISCs and niche signalling, the expression of delta-like ligand 4 (Dll4) was significantly decreased and the expression of genes associated with Notch signalling tended to decrease in the ileal crypts of SAMP1 mice. Conclusion The characteristic ileitis in SAMP1 mice may be caused by impaired Dll4-Notch signalling.

Notch1 signaling in NOTCH1-mutated mantle cell lymphoma depends on Delta-Like ligand 4 and is a potential target for specific antibody therapy

BackgroundNOTCH1 gene mutations in mantle cell lymphoma (MCL) have been described in about 5–10% of cases and are associated with significantly shorter survival rates. The present study aimed to investigate the biological impact of this mutation in MCL and its potential as a therapeutic target.MethodsActivation of Notch1 signaling upon ligand-stimulation and inhibitory effects of the monoclonal anti-Notch1 antibody OMP-52M51 in NOTCH1-mutated and -unmutated MCL cells were assessed by Western Blot and gene expression profiling. Effects of OMP-52M51 treatment on tumor cell migration and tumor angiogenesis were evaluated with chemotaxis and HUVEC tube formation assays. The expression of Delta-like ligand 4 (DLL4) in MCL lymph nodes was analyzed by immunofluorescence staining and confocal microscopy. A MCL mouse model was used to assess the activity of OMP-52M51 in vivo.ResultsNotch1 expression can be effectively stimulated in NOTCH1-mutated Mino cells by DLL4, whereas in the NOTCH1-unmutated cell line JeKo-1, less effect was observed upon any ligand-stimulation. DLL4 was expressed by histiocytes in both, NOTCH1-mutated and –unmutated MCL lymph nodes. Treatment of NOTCH1-mutated MCL cells with the monoclonal anti-Notch1 antibody OMP-52M51 effectively prevented DLL4-dependent activation of Notch1 and suppressed the induction of numerous direct Notch target genes involved in lymphoid biology, lymphomagenesis and disease progression. Importantly, in lymph nodes from primary MCL cases with NOTCH1/2 mutations, we detected an upregulation of the same gene sets as observed in DLL4-stimulated Mino cells. Furthermore, DLL4 stimulation of NOTCH1-mutated Mino cells enhanced tumor cell migration and angiogenesis, which could be abolished by treatment with OMP-52M51. Importantly, the effects observed were specific for NOTCH1-mutated cells as they did not occur in the NOTCH1-wt cell line JeKo-1. Finally, we confirmed the potential activity of OMP-52M51 to inhibit DLL4-induced Notch1-Signaling in vivo in a xenograft mouse model of MCL.ConclusionDLL4 effectively stimulates Notch1 signaling in NOTCH1-mutated MCL and is expressed by the microenvironment in MCL lymph nodes. Our results indicate that specific inhibition of the Notch1-ligand-receptor interaction might provide a therapeutic alternative for a subset of MCL patients.

ACTH controls thymocyte homeostasis independent of glucocorticoids.

It has been known for decades that lowering the circulating glucocorticoid (GC) concentration as in Addison's disease or after removing the adrenals results in thymus enlargement, largely due to thymocyte expansion. This has been attributed to the loss of the proapoptotic effects on thymocytes by adrenal GCs. Here, we test this concept and report that ACTH directly controls thymic growth post-adrenalectomy (ADX) independent of the proapoptotic effect of GCs. This was supported by the finding that ADX caused thymus enlargement and a 1.7-fold (P < 0.001) increase in thymocyte number in GR(LckCre) mice resistant to GC-induced thymocyte apoptosis, similar to the increase seen in wild-type mice (2.2-fold; P < 0.01). We show by immunostaining that melanocortin receptor subtype 2, which selectively binds ACTH, is partly expressed on the thymic epithelium. Furthermore, ACTH in comparison to vehicle induced a 2.0-fold (P < 0.01) increase in fetal thymic organ culture thymocyte numbers in vitro and enhanced 2.2-fold (P < 0.05) the expression of delta-like ligand 4, a factor that supports T-cell development. Additionally, adrenalectomized GR(LckCre) mice treated with ACTH under conditions that repressed endogenous ACTH secretion showed increased thymocyte cellularity (1.9-fold; P < 0.01) and splenic naive T-cell numbers (2.5-fold; P < 0.001) compared to when treated with PBS. Altogether, our results show that ACTH directly controls thymocyte homeostasis independent of GCs. These results revise the old paradigm behind compensatory thymus growth following ADX, now demonstrating that ACTH has a central role in regulating thymocyte expansion when systemic GC concentration is low.

Highlights of This Issue

The combination of bevacizumab, an anti-VEGF monoclonal antibody, with cytotoxic chemotherapy has shown improved progression-free survival in breast carcinoma. However, there is a need to develop biomarkers that can identify patients most likely to benefit from this therapy. Here, Jubb and colleagues examined a large panel of in situ biomarkers in archival tissue from patients enrolled in a phase 3 clinical trial of bevacizumab in breast cancer. Their findings suggest that expression of delta-like ligand 4, neuropilin-1, and VEGF-C may predict progression-free survival benefit from the addition of bevacizumab to capecitabine. Therefore, these biomarkers may aid in patient selection.Organic anion transporting polypeptides (OATPs) are broad specificity transmembrane uptake transporters. Using recently generated Oatp1a/1b cluster knockout mice, Van de Steeg and colleagues studied the role of Oatp1a/1b transporters in drug disposition. They found that Oatp1a/1b transporters play an important role in the in vivo pharmacokinetics of the hydrophobic anticancer drug paclitaxel, mainly by mediating its hepatic uptake. The impact of Oatp1a/1b transporters on the disposition of paclitaxel was unexpected as this drug was thought to mainly pass membranes by passive diffusion. These findings suggest that alterations in tumor or hepatic OATP activity might affect the therapeutic efficacy of paclitaxel.Breast cancer subtypes display characteristic and biologically meaningful gene expression profiles. Here, Graham and colleagues investigated gene expression profiles in histologically normal breast epithelium (NlEpi) microdissected from breasts with either ER+ or ER- breast cancers. They then compared these NlEpi profiles with profiles of ER+ and ER- cancers in 4 external datasets, and found that gene expression in each type of NlEpi resembled gene expression of the corresponding type of invasive breast cancer (i.e., ER+ or ER-). Thus, NlEpi gene expression may help elucidate subtype-specific risk signatures, identify early events in cancer development and locate targets for prevention and therapy.Hereditary head and neck paragangliomas (HNPGL) are associated with mutations in the SDHD (PGL1), SDHC (PGL3), and SDHB (PGL4) genes encoding succinate dehydrogenase subunits. Recently, mutations in the human SDHAF2 gene were described, and this gene was shown to be the ‘imprinted’ PGL2-gene. Here, Kunst and colleagues describe a new branch of the Dutch SDHAF2 (PLG2-SDH5) family and establish the SDHAF2-mutation status of PGL2-family members. The identification of the SDHAF2-mutation provides a useful aid in screening for HNPGL, and the phenotypic characterization of this SDHAF2 (PLG2-SDH5) family is valuable for future counseling of patients and families.

Expression of delta-like ligand 4 (Dll4) and markers of hypoxia in colon cancer

Background:Delta-like ligand 4 (Dll4) is a Notch ligand that is upregulated by hypoxia and vascular endothelial growth factor-A (VEGF-A) and is reported to have a role in tumor angiogenesis. Evidence from xenograft studies suggests that inhibiting Dll4–Notch signalling may overcome resistance to anti-VEGF therapy. The aim of this study was to characterise the expression of Dll4 in colon cancer and to assess whether it is associated with markers of hypoxia and prognosis.Method:In all, 177 colon cancers were represented in tissue microarrays. Immunohistochemistry was performed using validated antibodies against Dll4, VEGF, hypoxia-inducible factor (HIF)-1α, HIF-2α, prolyl hydroxylase (PHD)1, PHD2, PHD3 and carbonic anhydrase 9 (CA9).Results:The expression of Dll4 was observed preferentially in the endothelium of 71% (125 out of 175) of colon cancers, but not in the endothelium adjacent to normal mucosa (none out of 107, P<0.0001). The expression of VEGF was significantly associated with HIF-2α (P<0.0001) and Dll4 (P=0.010). Only HIF-2α had a significant multivariate prognostic effect (hazard ratio 1.61, 95% confidence interval 1.01–2.57). Delta-like ligand 4 was also expressed by neoplastic cells, particularly neoplastic goblet cells.Conclusion:Endothelial expression of Dll4 is not a prognostic factor, but is significantly associated with VEGF. Assessing endothelial Dll4 expression may be critical in predicting response to anti-VEGF therapies.