DCC Expression Research Articles

Cinnamaldehyde attenuates streptozocin-induced diabetic osteoporosis in a rat model by modulating netrin-1/DCC-UNC5B signal transduction.

Background: Cinnamaldehyde (CMD) is a major functional component of Cinnamomum verum and has shown treatment effects against diverse bone diseases. This study aimed to assess the anti-diabetic osteoporosis (DOP) potential of diabetes mellitus (DM) and to explore the underlying mechanism driving the activity of CMD. Methods: A DOP model was induced via an intraperitoneal injection of streptozocin (STZ) into Sprague-Dawley rats, and then two different doses of CMD were administered to the rats. The effects of CMD on the strength, remodeling activity, and histological structure of the bones were assessed. Changes in the netrin-1 related pathways also were detected to elucidate the mechanism of the anti-DOP activity by CMD. Results: CMD had no significant effect on the body weight or blood glucose level of the model rats. However, the data showed that CMD improved the bone strength and bone remodeling activity as well as attenuating the bone structure destruction in the DOP rats in a dose-dependent manner. The expression of netrin-1, DCC, UNC5B, RANKL, and OPG was suppressed, while the expression of TGF-β1, cathepsin K, TRAP, and RANK was induced by the STZ injection. CMD administration restored the expression of all of these indicators at both the mRNA and protein levels, indicating that the osteoclast activity was inhibited by CMD. Conclusion: The current study demonstrated that CMD effectively attenuated bone impairments associated with DM in a STZ-induced DOP rat model, and the anti-DOP effects of CMD were associated with the modulation of netrin-1/DCC/UNC5B signal transduction.

Netrin-1 ve Reseptörlerinin Çeşitli Kanserlerdeki Rolü

ABSTRACT
 Netrin-1 is a laminin-like protein that is secreted. It plays a role in the development of the nervous system and is also involved in processes such as cell migration, proliferation, angiogenesis, differentiation, apoptosis, metastasis, and invasion. DCC, neogenin, and UNC5 receptor families form the main receptors of netrin-1. These receptors have a dual role depending on the presence or absence of netrin-1. Netrin-1 influences carcinogenesis through signaling pathways such as PI3K/AKT, ERK/MAPK, Notch, and NF-kB. Netrin-1 receptor interactions are effective in cancer cell viability and carcinogenesis mechanisms. Overall, overexpression of netrin-1 and loss of its receptors promote carcinogenesis. Netrin-1 is involved in apoptosis through different receptors. Changes in the expression of DCC and UNC5H receptors affect cancer cell growth and metastasis. Loss of expression in dependent receptors is observed in advanced stages of various tumors. Neogenin is associated with migration and metastasis in tumors. Studies have shown that netrin-1 influences tumor development in various cancers such as gastric cancer, pancreatic ductal adenocarcinoma, colorectal cancer, and glioblastoma. Overexpression of netrin-1 is associated with poor prognosis and decreased overall survival. Netrin-1 levels are reported to be higher in patient groups compared to healthy control groups and decrease with chemotherapy. The mechanism of netrin-1 and its receptors in tumor development is not clear due to their different effects. This article summarizes research findings presenting the role and position of netrin-1 in various cancers.

Retracted: Expression and Relationship of Netrin-1, DCC, UNC5B, and VEGF in Villous Tissues of Patients with Delayed Abortion.

[This retracts the article DOI: 10.1155/2022/6283372.].

Relationship between insulin and Netrin-1/DCC guidance cue pathway regulation in the prefrontal cortex of rodents exposed to prenatal dietary restriction.

Fetal restriction (FR) alters insulin sensitivity, but it is unknown how the metabolic profile associated with restriction affects development of the dopamine (DA) system and DA-related behaviors. The Netrin-1/DCC guidance cue system participates in maturation of the mesocorticolimbic DA circuitry. Therefore, our objective was to identify if FR modifies Netrin-1/DCC receptor protein expression in the prefrontal cortex (PFC) at birth and mRNA in adulthood in rodent males. We used cultured HEK293 cells to assess if levels of miR-218, microRNA regulator of DCC, are sensitive to insulin. To assess this, pregnant dams were subjected to a 50% FR diet from gestational day 10 until birth. Medial PFC (mPFC) DCC/Netrin-1 protein expression was measured at P0 at baseline and Dcc/Netrin-1 mRNA levels were quantified in adults 15 min after a saline/insulin injection. miR-218 levels in HEK-293 cells were measured in response to insulin exposure. At P0, Netrin-1 levels are downregulated in FR animals in comparison to controls. In adult rodents, insulin administration results in an increase in Dcc mRNA levels in control but not FR rats. In HEK293 cells, there is a positive correlation between insulin concentration and miR-218 levels. Since miR-218 is a Dcc gene expression regulator and our in vitro results show that insulin regulates miR-218 levels, we suggest that FR-induced changes in insulin sensitivity could be affecting Dcc expression via miR-218, impacting DA system maturation and organization. As fetal adversity is linked to nonadaptive behaviors later in life, this may contribute to early identification of vulnerability to chronic diseases associated with fetal adversity.

Omics approaches to discover pathophysiological pathways contributing to human pain.

Omics approaches to discover pathophysiological pathways contributing to human pain.

Molecular and clinical analysis of genes involved in gastric cancer

Gastric cancer is the abnormal growth of stomach cells. The symptoms of this disease include difficulty in swallowing, heartburn, stomach pain, indigestion, nausea, vomiting, and blood in the stool. Gastric cancer is a multifactorial and genetic disease, and many genes and factors are involved in it. DCC and CDH1 are the genes silenced by hypermethylation in gastric cancer and play an influential role in suppressing gastric cancer tumors. The aim of this study was bioinformatics analysis at the genome and proteome level and evaluation and comparison of the expression of DCC and CDH1 genes in different human body tissues. The results of this study showed that the CDH1 gene is more expressed in the thyroid gland and Parathyroid gland and the DCC gene is more expressed in the testis, hippocampal formation, basal ganglia, midbrain, cerebral cortex, and hypothalamus. The expression analysis of these genes showed that both genes generally are more active in glands and have little expression in other body organs. Cellular analysis of DCC and CDH1 genes by antibodies that bind to the proteins of the target genes showed that both genes are active in the Golgi apparatus, with the difference that the DCC gene is more present in the nucleus and the CDH1 gene is more present in the plasma membrane. The expression level of the CDH1 gene is relatively higher than that of the DCC gene. Also, phenotypic studies of the DCC gene showed that this gene is related to colorectal cancer, and it was found that the CDH1 gene is effective in Blepharocheilodontic syndrome 1. Finally, considering the role of CDH1 and DCC genes as tumor suppressor genes, these items can be used for targeted treatments in gastric cancer.

Unique effects of social defeat stress in adolescent male mice on the Netrin-1/DCC pathway, prefrontal cortex dopamine and cognition (Social stress in adolescent vs. adult male mice).

For some individuals, social stress is a risk factor for psychiatric disorders characterized by adolescent onset, prefrontal cortex (PFC) dysfunction and cognitive impairments. Social stress may be particularly harmful during adolescence when dopamine (DA) axons are still growing to the PFC, rendering them sensitive to environmental influences. The guidance cue Netrin-1 and its receptor, DCC, coordinate to control mesocorticolimbic DA axon targeting and growth during this age. Here, we adapted the accelerated social defeat (AcSD) paradigm to expose male mice to social stress in either adolescence or adulthood and categorized them as “resilient” or “susceptible” based on social avoidance behavior. We examined whether stress would alter the expression of DCC and Netrin-1 in mesolimbic DA regions and would have enduring consequences on PFC DA connectivity and cognition. While in adolescence the majority of mice are resilient but exhibit risk-taking behavior, AcSD in adulthood leads to a majority of susceptible mice without altering anxiety-like traits. In adolescent, but not adult mice, AcSD dysregulates DCC and Netrin-1 expression in mesolimbic DA regions. These molecular changes in adolescent mice are accompanied by changes in PFC DA connectivity. Following AcSD in adulthood, cognitive function remains unaffected, but all mice exposed to AcSD in adolescence show deficits in inhibitory control when they reach adulthood. These findings indicate that exposure to AcSD in adolescence versus adulthood has substantially different effects on brain and behavior and that stress-induced social avoidance in adolescence does not predict vulnerability to deficits in cognitive performance.

MiR-218 in Adolescence Predicts and Mediates Vulnerability to Stress

BackgroundAdolescence is a period of increased vulnerability to psychiatric disorders, including depression. Discovering novel biomarkers to identify individuals who are at high risk is very much needed. Our previous work shows that the microRNA miR-218 mediates susceptibility to stress and depression in adulthood by targeting the netrin-1 guidance cue receptor gene Dcc in the medial prefrontal cortex (mPFC). MethodsHere, we investigated whether miR-218 regulates Dcc expression in adolescence and could serve as an early predictor of lifetime stress vulnerability in male mice. ResultsmiR-218 expression in the mPFC increases from early adolescence to adulthood and correlates negatively with Dcc levels. In blood, postnatal miR-218 expression parallels changes occurring in the mPFC. Notably, circulating miR-218 levels in adolescence associate with vulnerability to social defeat stress in adulthood, with high levels associated with social avoidance severity. Indeed, downregulation of miR-218 in the mPFC in adolescence promotes resilience to stress in adulthood. ConclusionsmiR-218 expression in adolescence may serve both as a marker of risk and as a target for early interventions.

MicroRNA-422a Inhibits DCC Expression in a Manner Dependent on SNP rs12607853

DCC netrin 1 receptor (DCC) affects the structure and function of the dopamine circuitry, which in turn affects the susceptibility to developing addiction. In a previous study, we found that single nucleotide polymorphism (SNP) rs12607853 in the 3′ untranslated region (3′-UTR) of DCC was significantly associated with heroin addiction. In the current study, we first used bioinformatics prediction to identify the DCC rs12607853 C allele as a potential hsa-miR-422a and hsa-miR-378c target site. We then used vector construction and dual-luciferase reporter assays to investigate the targeting relationship of DCC rs12607853 with hsa-miR-422a and hsa-miR-378c. The dual-luciferase reporter gene assay confirmed that the C allele of rs12607853 in combination with hsa-miR-422a led to repressed dual-luciferase gene expression. Moreover, gene expression assays disclosed that hsa-miR-422a inhibited DCC expression at both the mRNA and protein levels. We also found that morphine inhibited the expression of hsa-miR-422a but increased the expression of DCC mRNA, and this change in the expression of hsa-miR-422a could not be reversed by naloxone, which suggested that the role of DCC in opioid addiction might be regulated by hsa-miR-422a. In summary, this study improves our understanding of the role of hsa-miR-422a and identifies the genetic basis of rs12607853, which might contribute to the discovery of new biomarkers or therapeutic targets for opioid addiction.

DCC-related developmental effects of abused- versus therapeutic-like amphetamine doses in adolescence.

The guidance cue receptor DCC controls mesocortical dopamine development in adolescence. Repeated exposure to an amphetamine regimen of 4mg/kg during early adolescence induces, in male mice, downregulation of DCC expression in dopamine neurons by recruiting the Dcc microRNA repressor, microRNA-218 (miR-218). This adolescent amphetamine regimen also disrupts mesocortical dopamine connectivity and behavioral control in adulthood. Whether low doses of amphetamine in adolescence induce similar molecular and developmental effects needs to be established. Here, we quantified plasma amphetamine concentrations in early adolescent mice following a 4 or 0.5mg/kg dose and found peak levels corresponding to those seen in humans following recreational and therapeutic settings, respectively. In contrast to the high doses, the low amphetamine regimen does not alter Dcc mRNA or miR-218 expression; instead, it upregulates DCC protein levels. Furthermore, high, but not low, drug doses downregulate the expression of the DCC receptor ligand, Netrin-1, in the nucleus accumbens and prefrontal cortex. Exposure to the low-dose regimen did not alter the expanse of mesocortical dopamine axons or their number/density of presynaptic sites in adulthood. Strikingly, adolescent exposure to the low-dose drug regimen does not impair behavioral inhibition in adulthood; instead, it induces an overall increase in performance in a go/no-go task. These results show that developmental consequences of exposure to therapeutic- versus abused-like doses of amphetamine in adolescence have dissimilar molecular signatures and opposite behavioral effects. These findings have important clinical relevance since amphetamines are widely used for therapeutic purposes in youth.

The microRNAs let-7 and miR-9 down-regulate the axon-guidance genes Ntn1 and Dcc during peripheral nerve regeneration

Axon guidance helps growing neural axons to follow precise paths to reach their target locations. It is a critical step for both the formation and regeneration of neuronal circuitry. Netrin-1 (Ntn1) and its receptor, deleted in colorectal carcinoma (Dcc) are essential factors for axon guidance, but their regulation in this process is incompletely understood. In this study, using quantitative real-time RT-PCR (qRT-PCR) and biochemical and reporter gene assays, we found that the Ntn1 and Dcc genes are both robustly up-regulated in the sciatic nerve stump after peripheral nerve injury. Moreover, we found that the microRNA (miR) let-7 directly targets the Ntn1 transcript by binding to its 3'-untranslated region (3'-UTR), represses Ntn1 expression, and reduces the secretion of Ntn1 protein in Schwann cells. We also identified miR-9 as the regulatory miRNA that directly targets Dcc and found that miR-9 down-regulates Dcc expression and suppresses the migration ability of Schwann cells by regulating Dcc abundance. Functional examination in dorsal root ganglion neurons disclosed that let-7 and miR-9 decrease the protein levels of Ntn1 and Dcc in these neurons, respectively, and reduce axon outgrowth. Moreover, we identified a potential regulatory network comprising let-7, miR-9, Ntn1, Dcc, and related molecules, including the RNA-binding protein Lin-28 homolog A (Lin28), SRC proto-oncogene nonreceptor tyrosine kinase (Src), and the transcription factor NF-κB. In summary, our findings reveal that the miRs let-7 and miR-9 are involved in regulating neuron pathfinding and extend our understanding of the regulatory pathways active during peripheral nerve regeneration.

Egr-1 increases angiogenesis in cartilage via binding Netrin-1 receptor DCC promoter

BackgroundOsteoarthritis (OA) is a joint disease characterized by degradation of cartilage. The etiology of OA is still unclear. Vascular endothelial growth factor (VEGF) plays a key role of angiogenesis in the pathogenesis of OA and contributes to the angiogenesis of NT-1/DCC. Whether or not NT-1/DCC and VEGF interact in regulating angiogenesis of OA cartilage is not known.MethodsHistological studies for CD34, VEGF, and safranin-O staining were performed to determine angiogenesis and cartilage tissue injury. ELISA indicated the level of pro-inflammation cytokines. Immunoblotting, immunoprecipitation, and electrophoretic mobility shift assay (EMSA) were performed to assay the expression and function of NT-1/DCC-VEGF signaling pathway.ResultsOur data indicated that VEGF expression was increased in cartilage tissue from OA rats, while the chondrocytes were disorganized, and cartilage degeneration was increasing in OA rats. The inflammation factors in articular cavity fluid were higher in the OA rats than in the sham. The protein expression of NT-1, DCC, and VEGF were increased in osteoarthritic cartilage. DCC was involved in the positive regulation of osteoarthritic angiogenesis by VEGF. Egr-1 expression was higher in OA rats than in sham rats. Egr-1 is a regulator of DCC promoter activity, and the binding is higher in OA rats than in sham rats.ConclusionOur present study provides a mechanism by which Egr-1 induced angiogenesis via NT-1/DCC-VEGF pathway.

Alterations of Tumor Suppressor Genes Expression in Colorectal Cancer: Their Impact on Progression and Prediction of Patients Outcome

Background: Deregulation of tumor suppressor genes as APC, DCC and SMAD2 are related to tumorgenesis thus we aimed to investigate their expression among colorectal cancer to validate their relation with clinicopathological factors and the clinical outcome for CRC patients.
 Materials and Methods: Formalin-fixed paraffin samples from 115 colorectal cancer were investigated for APC, DCC and SMAD2 gene expression using quantitative PCR (QPCR) and their levels were analyzed versus clinicopathological factors and the overall survival (OS) of colorectal cancer patients.
 Results: A significant relation was reported between DCC and SMAD2 gene expression with clinical stages as they reported decrease expression among those with stage III. The three investigated genes were decreased significantly with poor histological differentiation colorectal cancer patients. The correlations between the expressions of the investigated genes revealed a significant correlation between SMAD2 and APC as well as between SMAD2 and DCC. Moreover patients with mean levels below and equal their expression values showed a considerable difference with OS.
 Conclusion: Gene expression of tumor suppressor genes APC, DCC and SMAD2 were significantly related to differential grading and patient's outcome thus pointing out their potential role as predictive markers for prognosis of colorectal cancer.

DCC Is Required for the Development of Nociceptive Topognosis in Mice and Humans

Avoidance of environmental dangers depends on nociceptive topognosis, or the ability to localize painful stimuli. This is proposed to rely on somatotopic maps arising from topographically organized point-to-point connections between the body surface andthe CNS. To determine the role of topographic organization of spinal ascending projections in nociceptive topognosis, we generated a conditional knockout mouse lacking expression of the netrin1 receptor DCC in the spinal cord. These mice have an increased number of ipsilateral spinothalamic connections and exhibit aberrant activation of the somatosensory cortex in response to unilateral stimulation. Furthermore, spinal cord-specific Dcc knockout animals displayed mislocalized licking responses to formalin injection, indicating impaired topognosis. Similarly, humans with DCC mutations experience bilateral sensation evoked by unilateral somatosensory stimulation. Collectively, our results constitute functional evidence of the importance of topographic organization of spinofugal connections for nociceptive topognosis.

Non-Contingent Exposure to Amphetamine in Adolescence Recruits miR-218 to Regulate Dcc Expression in the VTA.

The development of the dopamine input to the medial prefrontal cortex occurs during adolescence and is a process that is vulnerable to disruption by stimulant drugs such as amphetamine. We have previously linked the amphetamine-induced disruption of dopamine connectivity and prefrontal cortex maturation during adolescence to the downregulation of the Netrin-1 receptor, DCC, in dopamine neurons. However, how DCC expression in dopamine neurons is itself regulated is completely unknown. MicroRNA (miRNA) regulation of mRNA translation and stability is a prominent mechanism linking environmental events to changes in protein expression. Here, using male mice, we show that miR-218 is expressed in dopamine neurons and is a repressor of DCC. Whereas Dcc mRNA levels increase from early adolescence to adulthood, miR-218 exhibits the exact opposite switch, most likely maintaining postnatal Dcc expression. This dynamic regulation appears to be selective to Dcc since the expression of Robo 1, the other guidance cue receptor target of miR-218, does not vary with age. Amphetamine in adolescence, but not in adulthood, increases miR-218 in the VTA and this event is required for drug-induced downregulation of Dcc mRNA and protein expression. This effect seems to be specific to Dcc because amphetamine does not alter Robo1. Furthermore, the upregulation of miR-218 by amphetamine requires dopamine D2 receptor activation. These findings identify miR-218 as regulator of DCC in the VTA both in normal development and after drug exposure in adolescence.

Potential effect of mechano growth factor E-domain peptide on axonal guidance growth in primary cultured cortical neurons of rats.

Establishing appropriate synaptic connections and plasticity is a critical need in neuronal regeneration and development. Mechano growth factor (MGF) and its C-terminal E-domain peptide with 24 amino acids, MGF-Ct24E, are potential neuroprotective agents. Our preliminary study indicates that Netrin-1 can guide axonal growth and its expression is sensitive to MGF, but how MGF regulates the expression of Netrin-1 and its receptor DCC is still unclear. Here, we investigate the effect of MGF-Ct24E on the expression of Netrin-1 and DCC in primary cultured cortical neurons in vitro and the adult rat brain in vivo. MTT assay shows that MGF-Ct24E can significantly protect primary cortical neurons against nerve injury. There is a significant increase in axonal elongation after MGF-Ct24E treatment at concentrations of 0.5 and 1.0 μg/ml. Real-time polymerase chain reaction assay indicates that MGF-Ct24E can effectively promote the expression of Netrin-1 and DCC in primary cultured cortical neurons. To identify the certain mechanism of MGF-Ct24E on neuronal guidance and growth, adult rats are subjected to intramuscular injection of MGF-Ct24E after traumatic brain injury. Rats injected with MGF-Ct24E start eating and drinking within 14 days, indicating that MGF-Ct24E can promote rehabilitation. HE staining and immunohistochemistry assays of brain section slices reveal that MGF-Ct24E treatment can significantly inhibit the haemorrhage of traumatic brain injury and promote expression of Netrin-1. Further investigation of protein expression by Western blot assay shows that MGF-Ct24E promotes expression of Netrin-1 and DCC after nerve injury. MGF-Ct24E can effectively improve axonal guidance through upregulation of Netrin-1/DCC signalling in neuronal regeneration. Copyright © 2016 John Wiley & Sons, Ltd.

Genome-Wide Association Analysis Identifies Dcc as an Essential Factor in the Innervation of the Peripheral Vestibular System in Inbred Mice.

This study aimed to investigate the genetic causes of vestibular dysfunction. We used vestibular sensory-evoked potentials (VsEPs) to characterize the vestibular function of 35 inbred mouse strains selected from the Hybrid Mouse Diversity Panel and demonstrated strain-dependent phenotypic variation in vestibular function. Using these phenotypic data, we performed the first genome-wide association study controlling for population structure that has revealed two highly suggestive loci, one of which lies within a haplotype block containing five genes (Stard6, 4930503L19Rik, Poli, Mbd2, Dcc) on Chr. 18 (peak SNP rs29632020), one gene, deleted in colorectal carcinoma (Dcc) has a well-established role in nervous system development. An in-depth analysis of Dcc-deficient mice demonstrated elevation in mean VsEP threshold for Dcc (+/-) mice (-11.86dB) compared to wild-type (-9.68dB) littermates. Synaptic ribbon studies revealed Dcc (-/-) (P0) and Dcc (+/-) (6-week-old) mice showed lower density of the presynaptic marker (CtBP2) as compared to wild-type controls. Vestibular ganglion cell counts of Dcc (-/-) (P0) was lower than controls. Whole-mount preparations showed abnormal innervation of the utricle, saccule, and crista ampullaris at E14.5, E16.5, and E18.5. Postnatal studies were limited by the perinatal lethality in Dcc (-/-) mice. Expression analyses using in situ hybridization and immunohistochemistry showed Dcc expression in the mouse vestibular ganglion (E15.5), and utricle and crista ampullaris (6-week-old), respectively. In summary, we report the first GWAS for vestibular functional variation in inbred mice and provide evidence for the role of Dcc in the normal innervation of the peripheral vestibular system.

You-Gui pills promote nerve regeneration by regulating netrin1, DCC and Rho family GTPases RhoA, Racl, Cdc42 in C57BL/6 mice with experimental autoimmune encephalomyelitis

Ethnopharmacological relevanceYou-Gui pills (YGPs) are an effective traditional Chinese formula being used clinically for the treatment of multiple sclerosis (MS). Previous studies demonstrated that YGPs exerted the potent neuroprotective effects in murine models of experimental autoimmune encephalomyelitis (EAE), which is an equivalent animal model for multiple sclerosis (MS). However, the mechanism of YGPs functions remained unclear. Aim of this studyThe aim of this study was to evaluate the therapeutic effect of YGPs in MOG35–55-induced EAE mice and to further elucidate the underlying molecular mechanism. Methods: Female C57BL/6 mice were divided into six groups, including the non-treated EAE model, prednisone acetate- and 1.2, 2.4 or 4.8g/kg YGPs-treated EAE groups, and a normal control group. The EAE model was established by injecting the mice subcutaneously with MOG35–55 antigen. The body weights were measured and the neurological functions were scored in each group. The pathology and morphology of the brain and spinal cord was examined. The expression of MAP-2 was detected by immunofluorescent staining. The levels of netrin1, DCC, RhoA, Rac1, and Cdc42 were assayed by immunohistochemistry, qRT-PCR and Western blot on day 40 post-immunization (PI). ResultsYGPs treatments significantly reduced neurological function scores in EAE mice, where the inflammatory infiltration was reduced and the axon and myelin damage in both brain and spinal cord was alleviated. In the brain and spinal cord tissues, YGPs increased the expression of neuronal factors MAP-2, netrin1 and DCC. The expression of Rac1 and Cdc42 were increased, while RhoA was reduced following YGPs treatments. ConclusionOur results demonstrated that YGPs exhibited a neuroprotective effect on promoting nerve regeneration at the brain and spinal cord in EAE mice induced by MOG35–55. Netrin1, DCC and the Rho family GTPases of RhoA, Racl, Cdc42 were involved in mediating the effects of YGPs on nerve regeneration.

Complete Loss of Netrin-1 Results in Embryonic Lethality and Severe Axon Guidance Defects without Increased Neural Cell Death.

Netrin-1 regulates cell migration and adhesion during the development of the nervous system, vasculature, lung, pancreas, muscle, and mammary gland. It is also proposed to function as a dependence ligand that inhibits apoptosis; however, studies disagree regarding whether netrin-1 loss-of-function mice exhibit increased cell death. Furthermore, previously studied netrin-1 loss-of-function gene-trap mice express a netrin-1-β-galactosidase protein chimera with potential for toxic gain-of-function effects, as well as a small amount of wild-type netrin-1 protein. To unambiguously assess loss of function, we generated netrin-1 floxed and netrin-1 null mouse lines. Netrin-1(-/-) mice die earlier and exhibit more severe axon guidance defects than netrin-1 gene-trap mice, revealing that complete loss of function is more severe than previously reported. Netrin-1(-/-) embryos also exhibit increased expression of the netrin receptors DCC and neogenin that are proposed dependence receptors; however, increased apoptosis was not detected, inconsistent with netrin-1 being an essential dependence receptor ligand in the embryonic spinal cord.

Abstract 2457: Functional Study of DCC Gene in multiple myeloma mell lines

Abstract Functional Study of DCC Gene in Multiple Myeloma Cell Lines ABSTRACT INTRODUCTION: Multiple Myeloma (MM) is an incurable hematological malignancy characterized by multiorgan dysfunction as a result of bone marrow infiltration by malignant cells and the systemic damage of monoclonal circulating protein. Despite considerable progress in understanding MM biology, the molecular basis of this disease still remains open to debate. Previous data showed that DCC gene hypermethylation is significantly correlated with poor prognosis of MM patients. However, the involvement of DCC in the tumorigenesis process of MM remains unclear. PURPOSE: To better understand the role of DCC in this pathology through gene silencing in MM cell lines and evaluation of its interference in different tumorigenic processes. METHODS: The DCC gene expression was evaluated in three MM cell lines (RPMI-8226 and U266) and promoter methylation profile of this gene in the three cell lines was determined. The presence of DCC protein was confirmed by Western blotting (WB). The DCC expression was silenced by esiRNA and transfections were performed by electroporation. RESULTS: We detected the presence of aberrant methylation in DCC promoter in RPMI-8226, a cell line with undetectable expression of DCC. On the other hand, DCC was not methylated in U266, which present expression of DCC at mRNA and protein level. For this reason, DCC was silenced in U266 with esiRNA and its impact in the apoptosis, cell viability, proliferation and cell cycle processes was evaluated in this cell line. Support by FAPESP Citation Format: Dorival Mendes Rodrigues-Junior, Thais Priscilla Biassi, Viviane Carlin, Joel Machado-Junior, André Luiz Vettore. Functional Study of DCC Gene in multiple myeloma mell lines. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2457. doi:10.1158/1538-7445.AM2014-2457