Targeting netrin-1/DCC interaction in diffuse large B-cell and mantle cell lymphomas

Netrin-1 signaling pathway mechanisms in neurodegenerative diseases

Netrin-1 and its receptors play crucial roles in inducing axonal growth and neuronal migration during neuronal development. Their profound impacts then extend into adulthood to encompass the maintenance of neuronal survival and synaptic function. Increasing amounts of evidence highlight several key points: (1) Diminished Netrin-1 levels exacerbate pathological progression in animal models of Alzheimer's disease and Parkinson's disease, and potentially, similar alterations occur in humans. (2) Genetic mutations of Netrin-1 receptors increase an individuals' susceptibility to neurodegenerative disorders. (3) Therapeutic approaches targeting Netrin-1 and its receptors offer the benefits of enhancing memory and motor function. (4) Netrin-1 and its receptors show genetic and epigenetic alterations in a variety of cancers. These findings provide compelling evidence that Netrin-1 and its receptors are crucial targets in neurodegenerative diseases. Through a comprehensive review of Netrin-1 signaling pathways, our objective is to uncover potential therapeutic avenues for neurodegenerative disorders.

Insights from the neural guidance factor Netrin-1 into neurodegeneration and other diseases

Netrin-1 was initially discovered as a neuronal growth cue for axonal guidance, and its functions have later been identified in inflammation, tumorigenesis, neurodegeneration, and other disorders. We have recently found its alterations in the brains with Alzheimer's disease, which might provide important clues to the mechanisms of some unique pathologies. To provide better understanding of this promising molecule, we here summarize research progresses in genetics, pathology, biochemistry, cell biology and other studies of Netrin-1 about its mechanistic roles and biomarker potentials with an emphasis on clinical neurodegenerative disorders in order to expand understanding of this promising molecular player in human diseases.

Netrin-1 blockade inhibits tumour growth and EMT features in endometrial cancer

Netrin-1 is upregulated in cancers as a protumoural mechanism1. Here we describe netrin-1 upregulation in a majority of human endometrial carcinomas (ECs) and demonstrate that netrin-1 blockade, using an anti-netrin-1 antibody (NP137), is effective in reduction of tumour progression in an EC mouse model. We next examined the efficacy of NP137, as a first-in-class single agent, in a Phase I trial comprising 14 patients with advanced EC. As best response we observed 8 stable disease (8 out of 14, 57.1%) and 1 objective response as RECIST v.1.1 (partial response, 1 out of 14 (7.1%), 51.16% reduction in target lesions at 6 weeks and up to 54.65% reduction during the following 6 months). To evaluate the NP137 mechanism of action, mouse tumour gene profiling was performed, and we observed, in addition to cell death induction, that NP137 inhibited epithelial-to-mesenchymal transition (EMT). By performing bulk RNA sequencing (RNA-seq), spatial transcriptomics and single-cell RNA-seq on paired pre- and on-treatment biopsies from patients with EC from the NP137 trial, we noted a net reduction in tumour EMT. This was associated with changes in immune infiltrate and increased interactions between cancer cells and the tumour microenvironment. Given the importance of EMT in resistance to current standards of care2, we show in the EC mouse model that a combination of NP137 with carboplatin-paclitaxel outperformed carboplatin-paclitaxel alone. Our results identify netrin-1 blockade as a clinical strategy triggering both tumour debulking and EMT inhibition, thus potentially alleviating resistance to standard treatments.

DCC/netrin-1 regulates cell death in oligodendrocytes after brain injury

Hallmark pathological features of brain trauma are axonal degeneration and demyelination because myelin-producing oligodendrocytes (OLs) are particularly vulnerable to injury-induced death signals. To reveal mechanisms responsible for this OL loss, we examined a novel class of "death receptors" called dependence receptors (DepRs). DepRs initiate pro-death signals in the absence of their respective ligand(s), yet little is known about their role after injury. Here, we investigated whether the deleted in colorectal cancer (DCC) DepR contributes to OL loss after brain injury. We found that administration of its netrin-1 ligand is sufficient to block OL cell death. We also show that upon acute injury, DCC is upregulated while netrin-1 is downregulated in perilesional tissues. Moreover, after genetically silencing pro-death activity using DCCD1290N mutant mice, we observed greater OL survival, greater myelin integrity, and improved motor function. Our findings uncover a novel role for the netrin-1/DCC pathway in regulating OL loss in the traumatically injured brain.

Implication of Netrin-1 Gain of Expression in Canine Nodal Lymphoma

Simple Summary

Canine lymphomas represent one of the most frequent groups of neoplasia, for which prognosis may be poor. Treatments are based on polychemotherapy, with variable responses. As in human lymphomas, more and more targeted therapies are studied and developed. Therapy to restore apoptosis in neoplastic cells is one of them. Netrin-1 is a ligand of dependence receptors. When bound to its receptor, a positive signaling is triggered. When unbound, apoptosis is induced. In some human cancers, neoplastic cells can lose the ability to induce apoptosis by overexpressing netrin-1, or by decreasing the receptor expression. We hypothesized a similar pathway in canine lymphomas. We observed increased expression of netrin-1, particularly in high-grade nodal lymphomas. In vitro evaluation of an anti-netrin-1 antibody is encouraging as apoptosis is restored in a T-cell lymphoma cell line. Netrin-1 appears thus as a possible survival factor in dog lymphomas. This study suggests it can be a promising tool for a targeted therapy in lymphoma management in dogs.

Abstract

Netrin-1 is a member of the laminin superfamily, and is known to interact with specific receptors, called dependence receptors. While upon netrin-1 binding these receptors initiate positive signaling, in absence of netrin-1, these receptors trigger apoptosis. Tumor cells can avoid apoptosis by inactivating these receptors or by gaining ligand expression. The aim of the present study was to investigate the expression of netrin-1, the ligand of dependence receptors, in canine healthy lymph nodes (LN), and in lymphomas and to evaluate efficiency of a netrin-1 interfering compound in cell cultures from canine lymphoma. Thirty-two control LN and 169 lymphomas were analyzed through immunohistochemistry. Netrin-1 was expressed in the nucleoli of lymphoid and non-lymphoid cells in controls. Acquisition of a cytoplasmic expression was present in B-cell lymphomas (23.1 % in low-grade and 50.6% in high-grade) and T-cell lymphomas (50.0 % in low-grade and 78.8 % in high-grade), with a significant difference between the high- and low-grade in B-cell lymphomas. Through flow cytometry, we showed a significant increase in netrin-1 expression in either high-grade B-cell and T-cell lymphomas (19 and 5, respectively) compared with healthy LN (5), likewise an RT-qPCR analysis demonstrated a significant increase in netrin-1 expression level in 14 samples of lymphomas compared with eight samples of healthy LN. A T-cell aggressive canine lymphoma cell line and four primary canine nodal lymphomas cell cultures were treated with a netrin-1 interfering antibody. Apoptosis by measuring caspase 3 activity was significantly increased in the cell line and viability was decreased in three of the four primary cell cultures. Together, these data suggest that netrin-1 expression is increased in lymphoma, and more specifically in high-grade lymphomas, and that netrin-1 can act as a survival factor for the neoplastic cells, and so be a therapeutic target.

[Netrin-1, a novel antitumoral target]

Netrin-1, a secreted molecule that was first described for its role in guidance during embryogenesis, was then brought to light for its overexpression in a large number of aggressive cancers. Netrin-1 is a ligand of "dependence receptors". In adults, the interaction between Netrine-1 and these receptors triggers the survival, proliferation, and migration of different cell types. This will confer better survival properties to tumor cells, making them more prone to form aggressive tumors. A recently developed novel therapy aims at inhibiting the binding of Netrin-1 to these receptors in order to trigger cell death by apoptosis. This article presents a review of the functional characteristics of the Netrin-1 molecule, and the potential effects of a novel targeted therapy against Netrin-1 that could lead to very promising results in combination with conventional anti-cancer treatments.

Netrin-1 expression and targeting in multiple myeloma

Deleted in colorectal cancer (DCC) and uncoordinated-5 (UNC5) receptors, play a key role in tumor progression of several solid tumors by inducing apoptosis when unbound to their ligand netrin-1. Netrin 1 is currently being evaluated as a therapeutic target. These receptors, known as dependence receptors, and their ligands, have not yet been extensively explored in hematological malignancies. Here, we performed a screening of various human myeloma cell lines and bone marrow samples from multiple myeloma patients for netrin-1 and its receptors to determine the expression of netrin 1 and its receptors in multiple myeloma as well as to assess the potential anti-myeloma activity of a novel anti-netrin-1 treatment (NP137). Our results showed heterogeneous expression of netrin-1 and its receptors DCC and UNC5H2(B) in six human myeloma lines. Additionally, immunohistochemistry and flow cytometry showed expression of these molecules in a majority of myeloma patient samples. In vitro NP137 did not induce apoptosis of myeloma cell lines yet enhanced the cytotoxicity of bortezomib and dexamethasone. In vivo, NP137 treatment of SCID mice with established RPMI8226 myeloma tumors led to a reduction of tumor size compared to controls. Ex vivo, NP137 lowered the plasma cells percentage in bone marrow aspirates in a fraction of the patient samples analyzed. These results suggest that netrin signaling could constitute a novel therapeutic target in multiple myeloma.

Netrin-1 and its receptor DCC modulate survival and death of dopamine neurons and Parkinson's disease features

The netrin-1/DCC ligand/receptor pair has key roles in central nervous system (CNS) development, mediating axonal, and neuronal navigation. Although expression of netrin-1 and DCC is maintained in the adult brain, little is known about their role in mature neurons. Notably, netrin-1 is highly expressed in the adult substantia nigra, leading us to investigate a role of the netrin-1/DCC pair in adult nigral neuron fate. Here, we show that silencing netrin-1 in the adult substantia nigra of mice induces DCC cleavage and a significant loss of dopamine neurons, resulting in motor deficits. Because loss of adult dopamine neurons and motor impairments are features of Parkinson's disease (PD), we studied the potential impact of netrin-1 in different animal models of PD. We demonstrate that both overexpression of netrin-1 and brain administration of recombinant netrin-1 are neuroprotective and neurorestorative in mouse and rat models of PD. Of interest, we observed that netrin-1 levels are significantly reduced in PD patient brain samples. These results highlight the key role of netrin-1 in adult dopamine neuron fate, and the therapeutic potential of targeting netrin-1 signaling in PD.

Netrin-1 and Its Receptor DCC Are Causally Implicated in Melanoma Progression

Deleted in colorectal cancer (DCC), the receptor for the multifunctional cue netrin-1, acts as a tumor suppressor in intestinal cancer and lung metastasis by triggering cancer cell death when netrin-1 is lowly expressed. Recent genomic data highlighted that DCC is the third most frequently mutated gene in melanoma; we therefore investigated whether DCC could act as a melanoma tumor suppressor. Reexpressing DCC in human melanoma cell lines promoted tumor cell death and tumor growth inhibition in xenograft mouse models. Genetic silencing of DCC prodeath activity in a BRAF^V600E mouse model increased the proportion of mice with melanoma, further supporting that DCC is a melanoma tumor suppressor. Netrin-1 expression was elevated in melanoma compared with benign melanocytic lesions. Upregulation of netrin-1 in the skin cells of a BRAF^V600E-mutated murine model reduced cancer cell death and promoted melanoma progression. Therapeutic antibody blockade of netrin-1 combined with dacarbazine increased overall survival in several mouse melanoma models. Together, these data support that interfering with netrin-1 could be a viable therapeutic approach in patients with netrin-1-expressing melanoma. SIGNIFICANCE: Netrin-1 and its receptor DCC regulate melanoma progression, suggesting therapeutic targeting of this signaling axis as a viable option for melanoma treatment.

Exploring GRHL3 polymorphisms and SNP-SNP interactions in the risk of non-syndromic oral clefts in the Brazilian population

OBJECTIVE

To investigate the association of single-nucleotide polymorphisms (SNP) in grainyhead-like 3 (GRHL3) and to verify its possible interactions with others genes responsible for craniofacial development in the risk of non-syndromic oral cleft (NSOC).

METHODS

Applying TaqMan allelic discrimination assays, we evaluated GRHL3 SNPs (rs10903078, rs41268753, and rs4648975) in an ancestry-structured case-control sample composed of 1,127 Brazilian participants [272 non-syndromic cleft palate only (NSCPO), 242 non-syndromic cleft lip only (NSCLO), 319 non-syndromic cleft lip and palate (NSCLP), and 294 healthy controls]. Additionally, SNP-SNP interactions of GRHL3 and previously reported variants in FAM49A, FOXE1, NTN1, and VAX1 were verified in non-syndromic cleft lip with or without cleft palate (NSCL ± P). To eliminate false-positive associations, Bonferroni correction or 1,000 permutation method was applied.

RESULTS

The multiple logistic regression analysis showed that the CC genotype of rs10903078 (p = .03) and the haplotype C-C formed by the SNPs rs10903078 and rs41268753 (p = .04) were associated with NSCLO, but the p-values did not withstand Bonferroni correction. However, SNP-SNP test revealed significant interactions between GRHL3 SNPs and FAM49A (rs7552), FOXE1 (rs3758249), VAX1 (rs7078160 and rs751231), and NTN1 (rs9891446).

CONCLUSIONS

Our results confirm the importance of GRHL3 and its interactions with previously NSOC-associated genes, including FAM49A, FOXE1, NTN1, and VAX1, in the pathogenesis of NSOC in the Brazilian population.

Understanding the participation of GREM1 polymorphisms in nonsyndromic cleft lip with or without cleft palate in the Brazilian population

BACKGROUND

GREM1, which encodes Gremlin 1, an antagonist of bone morphogenic proteins with effects on proliferation and apoptosis, has been considered a candidate gene for nonsyndromic cleft lip with or without cleft palate (NSCL±P). In this study, we investigated potential associations of single nucleotide polymorphisms (SNP) in GREM1 and NSCL±P risk in the Brazilian population. Additionally, SNP-SNP interactions of GREM1 with previously reported rs1880646 variant in NTN1 (netrin 1), a gene also responsible for apoptotic phenotypes were verified.

METHODS

Applying Taqman allelic discrimination assays, we evaluated the variants rs16969681, rs16969816, rs16969862, and rs1258763 in 325 case-parent trios and in 1,588 isolated samples in a case-control study. Allelic and genotypic analyses, as well as interaction tests assessing gene-environmental factor (GxE) and SNP-SNP interaction with rs1880646 variant in NTN1, were performed based on logistic regression analysis adjusted for the effects of gender and genomic ancestry proportions.

RESULTS

The risk alleles of all SNP were undertransmitted in NSCL±P trios, though the case-control analysis confirmed only the association with rs16969862 alleles (OR: 0.78, 95% CI: 0.63-0.96, p = .02). The GxE interaction analysis revealed a significant interaction between maternal environmental contact with agrotoxics and rs16969816 (OR: 0.25, 95% CI: 0.08-0.74, p = .01), and pairwise interaction test with NTN1 rs1880646 yielded significant p values in the 1,000 permutation test for rs16969681, rs16969816, and rs16969862.

CONCLUSION

The GREM1 is involved in the etiology of NSCL±P in the Brazilian population and reveal that the interaction between GREM1 and NTN1 may be related with the pathogenesis of this common craniofacial malformation.

Predominance of triple wild-type and IGF2R mutations in mucosal melanomas

BACKGROUND

Primary mucosal melanoma (MM) is a rare subtype of melanoma that arises from melanocytes in the mucosa. MM has not been well profiled for mutations and its etiology is not well understood, rendering current treatment strategies unsuccessful. Hence, we investigated mutational landscape for MM to understand its etiology and to clarify mutations that are potentially relevant for MM treatment.

METHODS

Forty one MM and 48 cutaneous melanoma (CM) tissues were profiled for mutations using targeted deep next-generation sequencing (NGS) for 89 cancer-related genes. A total of 997 mutations within exons were analyzed for their mutational spectrum and prevalence of mutation, and 685 non-synonymous variants were investigated to identify mutations in individual genes and pathways. PD-L1 expression from 21 MM and 18 CM were assessed by immunohistochemistry.

RESULTS

Mutational spectrum analysis revealed a lower frequency of UV-induced DNA damage in MM than in CM (p = 0.001), while tobacco exposure was indicated as a potential etiologic factor for MM. In accordance with low UV damage signatures, MM demonstrated an overall lower number of mutations compared to CM (6.5 mutations/Mb vs 14.8 mutations/Mb, p = 0.001), and less PD-L1 expression (p = 0.003). Compared to CM, which showed frequent mutations in known driver genes (BRAF 50.0%, NRAS 29.2%), MM displayed lower mutation frequencies (BRAF; 12.2%, p < 0.001, NRAS; 17.1%), and was significantly more enriched for triple wild-type (no mutations in BRAF, RAS, or NF1, 70.7% vs 25.0%, p < 0.001), IGF2R mutation (31.7% vs 6.3%, p = 0.002), and KIT mutation (9.8% vs 0%, p = 0.042). Of clinical relevance, presence of DCC mutations was significantly associated with poorer overall survival in MM (log-rank test, p = 0.02). Furthermore, mutational spectrum analysis distinguished primary anorectal MM from CM metastasized to the bowel (spectrum analysis p < 0.001, number of mutations p = 0.002).

CONCLUSIONS

These findings demonstrated a potential etiologic factor and driver mutation for MM and strongly suggested that MM initiation or progression involves distinct molecular-mechanisms from CM. This study also identified mutational signatures that are clinically relevant for MM treatment.

The Ectodysplasin receptor EDAR acts as a tumor suppressor in melanoma by conditionally inducing cell death

Ectodysplasin receptor EDAR is seen as a typical Tumor Necrosis Factor receptor (TNFR) family member known to interact with its ligand Eda-A1, and signaling mainly through the nuclear factor-kappaB (NF-κB) and c-jun N-terminal kinases pathways. Mutations in genes that encode proteins involved in EDAR transduction cascade cause anhidrotic ectodermal dysplasia. Here, we report an unexpected pro-apoptotic activity of EDAR when unbound to its ligand Eda-A1, which is independent of NF-κB pathway. Contrarily to other death receptors, EDAR does recruit caspase-8 to trigger apoptosis but solely upon ligand withdrawal, thereby behaving as the so-called dependence receptors. We propose that pro-apoptotic activity of unbound EDAR confers it a tumor suppressive activity. Along this line, we identified loss-of-pro-apoptotic function mutations in EDAR gene in human melanoma. Moreover, we show that the invalidation of EDAR in mice promotes melanoma progression in a B-Raf mutant background. Together, these data support the view that EDAR constrains melanoma progression by acting as a dependence receptor.

The role of netrin-1 in metastatic renal cell carcinoma treated with sunitinib

Introduction

Clear-cell renal cell carcinoma (ccRCC) is the sixth most common malignancy in men in North America. Since ccRCC is a malignancy dependent on neovascularization, current first line systemic therapies like sunitinib, target the formation of new vessels allowing nutrient deprivation and cell death. However, recent studies have shown that patients develop resistance after approximately 1 year of treatment and show disease progression while on therapy. Therefore, we propose to identify the protein(s) responsible for increased migration with the aim of developing a new therapy that will target the identified protein and potentially slow down the progression of the disease.

Material and Methods

Human renal cancer cell lines (Caki-1, Caki-2, ACHN) were treated with increasing doses of sunitinib to develop a sunitinib-conditioned renal cell carcinoma cell line. mRNA microarray and qPCR were performed to compare the differences in gene expression between Caki-1 sunitinib-conditioned and non-conditioned cells. NTN1 was assessed in our in vivo sunitinib-conditioned mouse model using immunostaining. xCELLigence and scratch assays were used to evaluate migration and MTS was used to evaluate cell viability.

Results

Human renal cell carcinoma sunitinib-conditioned cell lines showed upregulation of netrin-1 in microarray and q-PCR. Increased migration was demonstrated in Caki-1 sunitinib-conditioned cells when compared to the non-treated ones as well as, increased endothelial cell migration. Silencing of netrin-1 in sunitinib-conditioned Caki-1 cells did not demonstrate a significant reduction in cell migration.

Conclusion

Netrin-1 is highly upregulated in renal cell carcinoma treated with sunitinib, but has no influence on cell viability or cell migration in metastatic RCC.

Molecular mechanisms of cell death: recommendations of the Nomenclature Committee on Cell Death 2018

Over the past decade, the Nomenclature Committee on Cell Death (NCCD) has formulated guidelines for the definition and interpretation of cell death from morphological, biochemical, and functional perspectives. Since the field continues to expand and novel mechanisms that orchestrate multiple cell death pathways are unveiled, we propose an updated classification of cell death subroutines focusing on mechanistic and essential (as opposed to correlative and dispensable) aspects of the process. As we provide molecularly oriented definitions of terms including intrinsic apoptosis, extrinsic apoptosis, mitochondrial permeability transition (MPT)-driven necrosis, necroptosis, ferroptosis, pyroptosis, parthanatos, entotic cell death, NETotic cell death, lysosome-dependent cell death, autophagy-dependent cell death, immunogenic cell death, cellular senescence, and mitotic catastrophe, we discuss the utility of neologisms that refer to highly specialized instances of these processes. The mission of the NCCD is to provide a widely accepted nomenclature on cell death in support of the continued development of the field.

Expression of Draxin in Lung Carcinomas

Guidance molecules, such as Netrin-1, and their receptors have important roles in controlling axon pathfinding, modulate biological activities of various cancer cells, and may be a useful target for cancer therapy. Dorsal repulsive axon guidance protein (Draxin) is a novel guidance molecule that binds not only common guidance molecule receptors with Netrin-1, but also directly binds the EGF domain of Netrin-1 through a 22-amino-acid peptide (22aa). By immunostaining, Draxin was positively expressed in small cell carcinoma, adenocarcinoma (ADC), and squamous cell carcinoma of the lung. In addition, western blot analysis revealed that Draxin was expressed in all histological types of lung cancer cell lines examined. Knockdown of Draxin in an ADC cell line H358 resulted in altered expression of molecules associated with proliferation and apoptosis. The Ki-67 labeling index of Draxin-knockdown ADC cells was increased compared to that of control ADC cells. In H358 cells, treatment of 22aa induced phosphorylation of histone H3, but did not change apoptosis-associated enzymes. These data suggest that Draxin might be involved in cell proliferation and apoptosis in lung adenocarcinoma cells.

Targeting netrin-1/DCC interaction in diffuse large B-cell and mantle cell lymphomas

DCC (Deleted in Colorectal Carcinoma) has been demonstrated to constrain tumor progression by inducing apoptosis unless engaged by its ligand netrin‐1. This has been shown in breast and colorectal cancers; however, this tumor suppressive function in other cancers is not established. Using a transgenic mouse model, we report here that inhibition of DCC‐induced apoptosis is associated with lymphomagenesis. In human diffuse large B‐cell lymphoma (DLBCL), an imbalance of the netrin‐1/DCC ratio suggests a loss of DCC‐induced apoptosis, either via a decrease in DCC expression in germinal center subtype or by up‐regulation of netrin‐1 in activated B‐cell (ABC) one. Such imbalance is also observed in mantle cell lymphoma (MCL). Using a netrin‐1 interfering antibody, we demonstrate both in vitro and in vivo that netrin‐1 acts as a survival factor for ABC‐DLBCL and MCL tumor cells. Together, these data suggest that interference with the netrin‐1/DCC interaction could represent a promising therapeutic strategy in netrin‐1‐positive DLBCL and MCL.