Project description:Pancreatic Ductal Adenocarcinoma (PDA) is a critical health issue in cancer field with little new therapeutic options. Several evidences support an implication of intra-tumoral microenvironment (stroma) on PDA progression. However, its contribution to the role of neuroplastic changes within pathophysiology and clinical course of PDA, mainly through tumor recurrence and neuropathic pain, remains unknown neglecting a putative therapeutic window. Here, we report that intra-tumoral microenvironment is a mediator of PDA Associated Neural Remodeling (PANR). With laser capture microdissection of stromal/tumoral compartment from human PDA followed by cDNA based microarray analyses we highlighted numerous factors expressed by stromal compartment that could impact on neuroplastic changes; among them, the Slit2/Robo axon guidance pathway. Using co-culture in vitro, we showed that stromal secreted Slit2 increases DRG neurite outgrowth and Schwann cells migration/proliferation by modulating N-Cadherin/β-Catenin signaling. Importantly, Slit2/Robo signaling inhibition disrupts this stromal/neural connection. Finally, we revealed in vivo that Slit2 expression is correlated with neural remodeling within Human and mouse PDA. These results demonstrate the implication of microenvironment, through secretion of axon guidance molecule, in PANR. Furthermore, it provides rationale to investigate the disruption of stromal/neural compartment dialogue by using Slit2/Robo pathway inhibitors for treatment of pancreatic cancer recurrence and associated pain. Freshly frozen tissue samples of PDACs were obtained from patients who underwent surgery. Patients underwent hemipancreaticoduodenectomy or distal pancreatectomy. No distant metastases were revealed at initial diagnosis. Histological examination confirmed diagnosis of PDAC in all cases. Prior to surgery all patients had signed an informed consent form that had been approved by the local ethics committee. Frozen sections were obtained from tissue samples of three tumors. After a brief staining sections were dehydrated and epithelial and stromal compartment has been microdissected using the PALM system. The microdissected material was immediately dissolute in a buffer containing β-mercaptoethanol and RNA carrier, and frozen before RNA extraction. Fifteen ug of total RNA was converted to biotinylated cRNA and hybridised to a human oligonucleotide array U133 Plus 2.0 (Genechip, Affymetrix, Santa Clara, CA).

Project description:During the development of the Drosophila central nervous system the process of midline crossing is orchestrated by a number of guidance receptors and ligands. Many key axon guidance molecules have been identified in both invertebrates and vertebrates, but the transcriptional regulation of growth cone guidance remains largely unknown. One open question is whether transcriptional regulation plays a role in midline crossing, or if local translation can account for the necessary fine tuning of protein levels. To investigate this issue, we conducted a genome wide analysis of transcription in Drosophila embryos using wild type and a number of well-characterized Drosophila guidance mutants and transgenics. We also analyzed a publicly available microarray time course of Drosophila embryonic development with an axon guidance focus. Using hopach, a novel clustering method which is well suited to microarray data analysis, we identified groups of genes with similar expression patterns across guidance mutants and transgenics. We then systematically characterized the resulting clusters with respect to their relevance to axon guidance using two complementary controlled vocabularies: the Gene Ontology (GO) and anatomical annotations of the Atlas of Pattern of Gene Expression (APoGE) in situ hybridization database. The analysis indicates that regulation of gene expression does play a role in the process of axon guidance in Drosophila. We also find a strong link between axon guidance and hemocyte migration, a result that agrees with mounting evidence that axon guidance molecules are co-opted in vertebrate vascularization. Cell cyclin activity in the context of axon guidance is also suggested from our array data. RNA and protein patterns of cell cyclin in axon guidance mutants and transgenics support this possible link. This study provides important insights into the regulation of axon guidance in vivo and suggests that transcription does play a role in control of axon guidance. Experiment Overall Design: Several mutants and transgenics were analyzed, totalizing 17 distinct conditions. Individual descriptions are included in each microarray. For each condition there are 3 or 4 replicates. The file's name indicates the replicates, e.g., comm.a reflects the replicate a of mutant commissureless. The experiment design covers a range of mutants and transgenics of key axon guidance mutans, in different dosages. The protocol was the standard Affymetrix protocol.

Project description:During the development of the Drosophila central nervous system the process of midline crossing is orchestrated by a number of guidance receptors and ligands. Many key axon guidance molecules have been identified in both invertebrates and vertebrates, but the transcriptional regulation of growth cone guidance remains largely unknown. One open question is whether transcriptional regulation plays a role in midline crossing, or if local translation can account for the necessary fine tuning of protein levels. To investigate this issue, we conducted a genome wide analysis of transcription in Drosophila embryos using wild type and a number of well-characterized Drosophila guidance mutants and transgenics. We also analyzed a publicly available microarray time course of Drosophila embryonic development with an axon guidance focus. Using hopach, a novel clustering method which is well suited to microarray data analysis, we identified groups of genes with similar expression patterns across guidance mutants and transgenics. We then systematically characterized the resulting clusters with respect to their relevance to axon guidance using two complementary controlled vocabularies: the Gene Ontology (GO) and anatomical annotations of the Atlas of Pattern of Gene Expression (APoGE) in situ hybridization database. The analysis indicates that regulation of gene expression does play a role in the process of axon guidance in Drosophila. We also find a strong link between axon guidance and hemocyte migration, a result that agrees with mounting evidence that axon guidance molecules are co-opted in vertebrate vascularization. Cell cyclin activity in the context of axon guidance is also suggested from our array data. RNA and protein patterns of cell cyclin in axon guidance mutants and transgenics support this possible link. This study provides important insights into the regulation of axon guidance in vivo and suggests that transcription does play a role in control of axon guidance. Keywords: Mutant Analysis

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Xenopus laevis

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