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Organoid-transplant model systems to study the effects of obesity on the pancreatic carcinogenesis in vivo

ABSTRACT: Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related mortality among adults in developed countries. The discovery of the most common genetic alterations as well as the development of organoids models’ of pancreatic cancer has provided insight into the fundamental pathways driving tumour progression from a normal cell, to non-invasive precursor lesion, to widely metastatic disease, offering new opportunities for identifying the key driver of cancer evolution. Obesity is one of the most serious public health challenges of the 21st century. Several epidemiological studies have shown the positive association between obesity and cancer-related morbidity/mortality, as well as poor prognosis and poorer treatment outcome. Despite strong evidence indicates a link between obesity and cancer incidence, the molecular basis of the initiating events remains largely elusive. This is mainly due to the lack of an accurate and reliable model of pancreatic carcinogenesis that mimics human obesity-associated PDAC, making data interpretation difficult and often confusing. Here we propose a suitable and manageable preclinical tool, organoids-based, to study the effects of obesity on pancreatic carcinogenesis. Therefore, we tracked the effects of obesity on the natural evolution of PDAC in a genetically defined transplantable model of the syngeneic murine pancreatic preneoplastic lesion (mP) and tumour (mT) derived-organoids that recapitulates the progression of human disease from early preinvasive lesions to metastatic disease. Our results suggest that organoid-derived transplants in obese mice represent a suitable system to study early steps of pancreatic carcinogenesis and support the hypothesis that inflammation induced by obesity stimulates tumour progression and metastatization during pancreatic carcinogenesis.

ORGANISM(S): Mus musculus

PROVIDER: GSE148135 | GEO | 2020/04/07

REPOSITORIES: GEO

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Project description:Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related mortality among adults in developed countries. The discovery of the most common genetic alterations as well as the development of organoids models of pancreatic cancer have provided insight into the fundamental pathways driving the progression from normal cell, to non-invasive precursor lesion, to widely metastatic disease, offering new opportunities for the discovery of key activated pathways along cancer progression. Obesity is one of the most serious public health challenges of the 21st century. Several epidemiological studies have shown the positive association between obesity and cancer-related morbidity/mortality, as well as poor prognosis and poorer treatment outcome. Despite strong evidence indicates a link between obesity and cancer incidence, the molecular basis of the initiating events remains largely elusive. This is mainly due to the lack of an accurate and reliable model of pancreatic carcinogenesis that mimics human obesity-associated PDAC, making data interpretation difficult and often confusing. Here we propose, to our knowledge, the best suitable and manageable preclinical tool, based on next-generation cell culture models, to study the effects of obesity on pancreatic carcinogenesis. Therefore we tracked the effects of obesity on the natural evolution of PDAC in a genetically-defined transplantable model of syngeneic murine pancreatic preneoplastic lesion (mP) and tumor (mT) derived organoids that recapitulates the progression of human disease from early preinvasive lesions to metastatic disease. Our models indicated that both genetic- and diet-induced obesity promoted incidence engraftment rate and growth of both preneoplastic and neoplastic organoids, favoring pancreatic cancer progression and distant metastases dissemination. Our obesity models of carcinogenesis mimic the evolution of human pancreatic cancer pathology, promoting carcinogenesis and concomitant accumulation of a myeloid infiltrate. These changes in cancer immune infiltrate were also associated to a specific pattern of anti-inflammatory Th2 signature. Moreover, gene expression profile analysis revealed a change in gene expression programs that addresses cells to different pancreatic subtypes and stromal conditions. Our results suggest that organoid-derived transplants in obese mice represent a suitable system to study early step of carcinogenesis and support the hypothesis that inflammation induced by obesity stimulates tumor progression and metastatization during pancreatic carcinogenesis.

Project description:Pancreatic ductal adenocarcinoma (PDAC) is a heterogeneous cancer in which differences in survival rates might be related to a variety in gene expression profiles. Although the molecular biology of PDAC begins to be revealed, genes or pathways that specifically drive tumour progression or metastasis are not well understood. Therefore, we performed microarray analyses on whole-tumour samples of 2 human PDAC subpopulations with similar clinicopathological features, but extremely distinct survival rates after potentially curative surgery, i.e., good outcome (OS and DFSM-bM-^@M-^I>M-bM-^@M-^I50M-bM-^@M-^Imonths) versus bad outcome (OSM-bM-^@M-^I<M-bM-^@M-^I19M-bM-^@M-^Imonths and DFSM-bM-^@M-^I<M-bM-^@M-^I7M-bM-^@M-^Imonths). Additionally, liver- and peritoneal metastases were analysed and compared to primary cancer tissue. The integrin and ephrin receptor families were upregulated in all PDAC samples, irrespective of outcome, supporting an important role of the interaction between pancreatic cancer cells and the surrounding desmoplastic reaction in tumorigenesis and cancer progression. Moreover, some components, such as ITGB1 and EPHA2, were upregulated in PDAC samples with a poor outcome, Additionally, overexpression of the non-canonical Wnt/M-NM-2-catenin pathway and EMT genes in PDAC samples with bad versus good outcome suggests their contribution to the invasiveness of pancreatic cancer, with M-NM-2-catenin being also highly upregulated in metastatic tissue. Thus, we conclude that components of the integrin and ephrin pathways and EMT-related genes might serve as molecular markers in pancreatic cancer as their expression seems to be related with prognosis. Microarray analysis was performed on 'Good' and 'Bad' patient samples (samples with similar pathological characteristics were chosen based on the definition of the 2 diverse survival outcome groups and the required RIN values above 7.1), on surrounding non-tumoural pancreatic control samples, liver metastasis (LM) and peritoneal metastasis (PM). Comparisons between good vs. control, bad vs. control, good vs. bad, and primary pancreatic cancer versus metastasis were performed.

Project description:Epigenetic modifications, particularly DNA methylation have been increasingly implicated in cancer. Although some genes display aberrant methylation in pancreatic cancer, a comprehensive global analysis is yet to be performed. To define the genome-wide pattern of DNA methylation in pancreatic ductal adenocarcinomas (PDAC), the methylation profile of 156 PDAC and 23 non-malignant pancreas was captured using high-density arrays. More than 90,000 CpG sites were significantly differentially methylated (DM) in PDAC relative to non-malignant pancreas, with pronounced alterations in a sub-set of 13,517 CpG sites. This sub-set of differentially methylated CpG sites segregated PDAC from non-malignant pancreas, regardless of tumour cellularity. As expected, PDAC hyper-methylation was most prevalent in the 5’ region of genes (including the proximal promoter, 5’UTR and CpG islands). From 3981 genes aberrantly methylated, approximately 36% showed significant correlation between methylation and mRNA expression levels. Pathway analysis revealed an enrichment of aberrant methylation in genes involved in key molecular mechanisms important to PDAC: TGF-β, WNT, Integrin signaling, Cell adhesion, Stellate cell activation and Axon guidance. Bisulfite amplicon deep sequencing and qRT-PCR expression analyses of axon guidance pathway genes SLIT2, SLIT3, ROBO1, ROBO3, SRGAP1, and MET suggested epigenetic suppression of SLIT-ROBO signaling and up-regulation of MET expression. Hypo-methylation of MET and ITGA2 correlated with high gene expression, which correlated with poor survival of PDAC patients. These data suggest that aberrant methylation plays an important role in pancreatic carcinogenesis affecting known core signaling pathways with important implications for disease pathophysiology and therapy. This dataset includes gene expression data from 103 primary tumour samples. 86 samples from this dataset have already been deposited into GEO (GSE36924), and has been duplicated here since the data has been processed differently. This data is also available through the International Cancer Genome Consortium (ICGC) Data Portal (http://dcc/icgc.org), under the project code: Pancreatic Cancer (QCMG, AU). Access to the restricted clinical data must be made through the ICGC Data Access Compliance Office (http://www.icgc.org/daco). This dataset contains gene expression array data from 103 primary pancreatic ductal adenocarcinoma samples. All samples have 1 biological replicate. These data have corresponding methylation 450K array data (GSE49149).

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Organoid-transplant model systems to study the effects of obesity on the pancreatic carcinogenesis in vivo

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