Deficiencies in Natural Killer Cell Numbers, Expansion, and Function at the Pre-Neoplastic Stage of Pancreatic Cancer by KRAS Mutation in the Pancreas of Obese Mice.
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ABSTRACT:
SUBMITTER: Kaur K
PROVIDER: S-EPMC6021953 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:The current paradigm of pancreatic neoplastic transformation proposes an initial step whereby acinar cells convert into acinar-to-ductal metaplasias, followed by progression of these lesions into neoplasias under sustained oncogenic activity and inflammation. Understanding the molecular mechanisms driving these processes is crucial to the early diagnostic and prevention of pancreatic cancer. Emerging evidence indicates that transcription factors that control exocrine pancreatic development could have either, protective or facilitating roles in the formation of preneoplasias and neoplasias in the pancreas. We previously identified that the homeodomain transcription factor Prox1 is a novel regulator of mouse exocrine pancreas development. Here we investigated whether Prox1 function participates in early neoplastic transformation using in vivo, in vitro and in silico approaches. We found that Prox1 expression is transiently re-activated in acinar cells undergoing dedifferentiation and acinar-to-ductal metaplastic conversion. In contrast, Prox1 expression is largely absent in neoplasias and tumors in the pancreas of mice and humans. We also uncovered that Prox1-heterozygosis markedly increases the formation of acinar-to-ductal-metaplasias and early neoplasias, and enhances features associated with inflammation, in mouse pancreatic tissues expressing oncogenic Kras. Furthermore, we discovered that Prox1-heterozygosis increases tissue damage and delays recovery from inflammation in pancreata of mice injected with caerulein. These results are the first demonstration that Prox1 activity protects pancreatic cells from acute tissue damage and early neoplastic transformation. Additional data in our study indicate that this novel role of Prox1 involves suppression of pathways associated with inflammatory responses and cell invasiveness.
| S-EPMC4796801 | biostudies-literature
Project description:SUMMARY Medulloblastoma is the most common malignant brain tumor in children. It is thought to result from transformation of granule cell precursors (GCPs) in the developing cerebellum, but little is known about the early stages of the disease. Here we identify a pre-neoplastic stage of medulloblastoma in patched heterozygous mice, a model of the human disease. We show that pre-neoplastic cells are present in the majority of patched mutants, although only 16% of these mice develop tumors. Pre-neoplastic cells, like tumor cells, exhibit activation of the Sonic hedgehog pathway and constitutive proliferation. Importantly, they also lack expression of the wild-type patched allele, suggesting that loss of patched is an early event in tumorigenesis. While pre-neoplastic cells resemble GCPs and tumor cells in many respects, they have a distinct molecular signature. Genes that mark the pre-neoplastic stage include regulators of migration, apoptosis and differentiation, processes critical for normal development but previously unrecognized for their role in medulloblastoma. The identification and molecular characterization of pre-neoplastic cells provides insight into the early steps in medulloblastoma formation, and may yield important markers for early detection and therapy of this disease. ANIMALS Patched heterozygous mice (Goodrich et al., 1997) were obtained from Matthew Scott's lab at Stanford, and maintained by breeding with 129X1/SvJ mice from Jackson Laboratories. Math1-GFP transgenic mice (Lumpkin et al., 2003) were provided by Jane Johnson at UT Southwestern Medical Center. Math1-GFP/patched+/- mice were generated by crossing patched heterozygotes with Math1-GFP mice, and then backcrossing to Math1-GFP mice three times before further analysis. All mice were maintained in the Cancer Center Isolation Facility at Duke University Medical Center. ISOLATION OF CELLS Granule cell precursors (GCPs) were isolated from 7-day-old (P7) patched+/- mice; preneoplastic cells were obtained from 6 week-old patched mutants; and tumor cells were obtained from 10-25-week old patched mutants displaying physical and behavioral signs of medulloblastoma. Cells were isolated from each source using a protocol described in (Wechsler- Reya and Scott, 1999). Briefly, cerebella were digested in solution containing 10 U/ml papain Oliver et al. Pre-Neoplastic Stage of Medulloblastoma - 8 - (Worthington, Lakewood, NJ) and 250 U/ml DNase (Sigma) and triturated to obtain a cell suspension. This suspension was centrifuged through a step gradient of 35% and 65% Percoll (Amersham Biosciences, Piscataway, NJ), and cells were harvested from the 35%-65% interface. Cells were resuspended in serum-free culture medium consisting of Neurobasal containing B27 supplement, sodium pyruvate, L-glutamine, and penicillin/streptomycin (all from Invitrogen, Carlsbad, California) and counted on a hemacytometer. Cells used for RNA isolation were centrifuged and flash frozen in liquid nitrogen. For proliferation assays or immunostaining, cells were plated on poly-D-lysine (PDL)-coated tissue culture vessels and incubated in serum-free culture medium. MICROARRAY HYBRIDIZATION AND ANALYSIS RNA from GCPs, pre-neoplastic cells and tumor cells (isolated as described above, but not FACS-sorted) and from normal adult cerebellum (not dissociated) was converted to cDNA using the Superscript Choice cDNA kit (Invitrogen) and a T7-dT(24) primer (Genset/Proligo, Boulder, CO). cRNA was generated using a T7-transcription/labeling kit from Enzo Life Sciences and hybridized to Affymetrix U74Av2 chips (Affymetrix, Santa Clara, CA). Chips were scanned, and hybridization data were acquired using Affymetrix Suite 5.0 software. Affymetrix CEL files were normalized and quantified using Bioconductor software with the gcRMA model to quantify gene expression levels (Gentleman and Carey, 2002). Unsupervised principal components analysis (PCA) was used to identify the relationships among normal adult cerebellum, GCPs, pre-neoplastic cells and tumor cells based on expression profiles. To identify genes that were differentially expressed among GCPs, pre-neoplastic cells and tumor cells, supervised analysis was carried out. A gene-by-gene ANOVA model with three groups (GCP, pre-neoplastic, tumor) was used to fit the log2-transformed intensities. To correct for multiple comparisons, the nominal p-value was adjusted using the false discovery rate (Benjamini and Hochberg, 1995). Genes were considered to be differentially expressed if they satisfied all of the following criteria: a difference in expression greater than 1.9-fold between any two groups, a maximum absolute intensity difference larger than 32 units, and an adjusted pvalue < 0.01. There were 118 genes that met these criteria. The identities of differentially expressed genes were verified by integrating data from the Affymetrix and Unigene databases. Gene functions were determined using information from Gene Ontology, Unigene, LocusLink and PubMed databases. Clustering was performed with Cluster and Treeview (Eisen et al., 1998). All statistical analysis was performed using R-1.7 software (Dalgaard, 2002). Results were visualized with Spotfire 6.0 (Somerville, MA). CORRESPONDING AUTHOR Robert J. Wechsler-Reya* Dept. of Pharmacology & Cancer Biology, Duke University Medical Center Box 3813, Durham, NC 27710 Phone: 919-613-8754. Fax: 919-668-3556. Email: rw.reya@duke.edu Keywords = medulloblastoma Keywords = brain tumor Keywords = pre-neoplastic Keywords = patched Keywords = hedgehog Keywords = migration Keywords = differentiation
2005-03-22 | GSE2426 | GEO
Project description:Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease and a major health problem in the United States. While the cytokine TGF-? has been implicated in PDAC development, it can exert both pro-tumorigenic and anti-tumorigenic effects that are highly context dependent and incompletely understood. Using three-dimensional (3D) cultures of KrasG12D-expressing mouse pancreatic epithelial cells we demonstrated that while exposure to exogenous TGF-? induced growth arrest of the KrasG12D cells, its subsequent removal allowed the cells to enter a hyper-proliferative, partially mesenchymal (PM), and progenitor-like state. This state was highly stable and was maintained by autocrine TGF-? signaling. While untreated KrasG12D cells formed cystic lesions in vivo, PM cells formed ductal structures resembling human PanINs, suggesting that they had attained increased oncogenic potential. Supporting this hypothesis, we determined that the PM cells share salient molecular and phenotypic features with the quasi-mesenchymal/squamous subtype of human PDAC, which has the worst prognosis of any of the recently identified subtypes. Transient pulses of TGF-? have been observed during pancreatitis, a major risk factor for PDAC. Our data suggest that transient TGF-? exposure is sufficient to induce the acquisition of stable PDAC-associated phenotypes in pre-neoplastic KrasG12D cells, providing novel molecular insight into the complex role of TGF-? in tumorigenesis.
| S-EPMC6076343 | biostudies-literature
Project description:Although the cell of origin for pancreatic cancer remains unknown, prior studies have suggested that pancreatic neoplasia may be initiated in progenitor-like cells. To examine the effects of oncogene activation within the pancreatic progenitor pool, we devised a system for real-time visualization of both normal and oncogenic KRAS-expressing pancreatic progenitor cells in living zebrafish embryos.By using BAC transgenes under the regulation of ptf1a regulatory elements, we expressed either extended green fluorescent protein (eGFP) alone or eGFP fused to oncogenic KRAS in developing zebrafish pancreas.After their initial specification, normal eGFP-labeled pancreatic progenitor cells were observed to actively migrate away from the forming endodermal gut tube, and subsequently underwent characteristic exocrine differentiation. In contrast, pancreatic progenitor cells expressing oncogenic KRAS underwent normal specification and migration, but failed to differentiate. This block in differentiation resulted in the abnormal persistence of an undifferentiated progenitor pool, and was associated with the subsequent formation of invasive pancreatic cancer. These tumors showed several features in common with the human disease, including evidence of abnormal Hedgehog pathway activation.These results provide a unique view of the tumor-initiating effects of oncogenic KRAS in a living vertebrate organism, and suggest that zebrafish models of pancreatic cancer may prove useful in advancing our understanding of the human disease.
| S-EPMC2654247 | biostudies-literature
Project description:Pre-diabetic patients have a high risk of developing diabetes as well as other associated diseases. From the viewpoint of risk assessment and to assist the development of protective therapies, we focused on the functional role of natural killer T (NKT) cells in pre-diabetes. We found that the expression of an NKT cell marker gene, Va14-Ja18, was significantly lower in specific tissues/organs such as adipose tissue and pancreas in non-obese pre-diabetes model mice than in their normal littermates. Subsequently, in the pre-diabetes model mice, Va14-Ja18 was activated with ?-galactosylceramide (?-GalCer) and its effect on glucose tolerance was estimated. The simultaneous injection of ?-GalCer and lymphocytes improved glucose tolerance with its maximum effect on the 3rd day. An analysis of circulating cytokine levels revealed that interferon-?, which is a pro-inflammatory cytokine, was secreted only on the 1st day after treatment with ?-GalCer and that interleukin (IL)-4, which is an anti-inflammatory cytokine, was secreted from the 1st to the 4th day. The prolonged secretion of IL-4 was thought to substantially contribute to the improvement of glucose tolerance. Based on these results, the functional role of NKT cells in pre-diabetes is to improve metabolic dysfunctions.
| S-EPMC5809671 | biostudies-literature
Project description:BackgroundMedulloblastomas are malignant childhood brain tumors that arise due to the aberrant activity of developmental pathways during postnatal cerebellar development and in adult humans. Transcriptome analysis has identified four major medulloblastoma subgroups. One of them, the Sonic hedgehog (SHH) subgroup, is caused by aberrant Hedgehog signal transduction due to mutations in the Patched1 (PTCH1) receptor or downstream effectors. Mice carrying a Patched-1 null allele (Ptch1∆/+) are a good model to study the alterations underlying medulloblastoma development as a consequence of aberrant Hedgehog pathway activity.ResultsTranscriptome analysis of human medulloblastomas shows that SERPINE2, also called Protease Nexin-1 (PN-1) is overexpressed in most medulloblastomas, in particular in the SHH and WNT subgroups. As siRNA-mediated lowering of SERPINE2/PN-1 in human medulloblastoma DAOY cells reduces cell proliferation, we analyzed its potential involvement in medulloblastoma development using the Ptch1∆/+ mouse model. In Ptch1∆/+ mice, medulloblastomas arise as a consequence of aberrant Hedgehog pathway activity. Genetic reduction of Serpine2/Pn-1 interferes with medulloblastoma development in Ptch1∆/+ mice, as ~60% of the pre-neoplastic lesions (PNLs) fail to develop into medulloblastomas and remain as small cerebellar nodules. In particular the transcription factor Atoh1, whose expression is essential for development of SHH subgroup medulloblastomas is lost. Comparative molecular analysis reveals the distinct nature of the PNLs in young Ptch1∆/+Pn-1Δ/+ mice. The remaining wild-type Ptch1 allele escapes transcriptional silencing in most cases and the aberrant Hedgehog pathway activity is normalized. Furthermore, cell proliferation and the expression of the cell-cycle regulators Mycn and Cdk6 are significantly reduced in PNLs of Ptch1∆/+Pn-1Δ/+ mice.ConclusionsOur analysis provides genetic evidence that aberrant Serpine2/Pn-1 is required for proliferation of human and mouse medulloblastoma cells. In summary, our analysis shows that Serpine2/PN-1 boosts malignant progression of PNLs to medulloblastomas, in which the Hedgehog pathway is activated in a SHH ligand-independent manner.
| S-EPMC4406471 | biostudies-literature
Project description:Despite expression of oncogenic KRAS, premalignant pancreatic intraepithelial neoplasia 1 (PanIN1) lesions rarely become fully malignant pancreatic ductal adenocarcinoma (PDAC). The molecular mechanisms through which established risk factors, such as chronic pancreatitis, acinar cell damage, and/or defective autophagy increase the likelihood of PDAC development are poorly understood. We show that accumulation of the autophagy substrate p62/SQSTM1 in stressed KrasG12D acinar cells is associated with PDAC development and maintenance of malignancy in human cells and mice. p62 accumulation promotes neoplastic progression by controlling the NRF2-mediated induction of MDM2, which acts through p53-dependent and -independent mechanisms to abrogate checkpoints that prevent conversion of differentiated acinar cells to proliferative ductal progenitors. MDM2 targeting may be useful for preventing PDAC development in high-risk individuals.
| S-EPMC5730340 | biostudies-literature
Project description:Fluorescence and light microscopy are important tools in the history of natural science. However, the resolution of microscopes is limited by the diffraction of light. One possible method to circumvent this physical restriction is the recently developed expansion microscopy (ExM). However, the original ultrastructure ExM (U-ExM) protocol is very time-consuming, and some epitopes are lost during the process. In this study, we developed a shortened pre-gelation staining ExM (PS-ExM) protocol and tested it to investigate the Plasmodium liver stage. The protocol presented in this study allows expanding of pre-stained samples, which results in shorter incubation times, better preservation of some epitopes and the advantage that non-expanded controls can be performed alongside using the same staining protocol. The protocol applicability was accessed throughout the Plasmodium liver stage, showing isotropic five-fold expansion. Furthermore, we used PS-ExM to visualise parasite mitochondria as well as the association of lysosomes to the parasitophorous vacuole membrane (PVM) as an example of visualising host-pathogen interaction. We are convinced that this new tool will be helpful for a deeper understanding of the biology of the Plasmodium liver stage.
| S-EPMC10729816 | biostudies-literature
Project description:High risk (oncogenic) human papillomavirus (HPV) infection causes cervical cancer. Infections are common but most clear naturally. Persistent infection can progress to cancer. Pre-neoplastic disease (cervical intraepithelial neoplasia/CIN) is classified by histology (CIN1-3) according to severity. Cervical abnormalities are screened for by cytology and/or detection of high risk HPV but both methods are imperfect for prediction of which women need treatment. There is a need to understand the host virus interactions that lead to different disease outcomes and to develop biomarker tests for accurate triage of infected women. As cancer is increasingly presumed to develop from proliferative, tumour initiating, cancer stem cells (CSCs), and as other oncogenic viruses induce stem cell associated gene expression, we evaluated whether presence of mRNA (detected by qRT-PCR) or proteins (detected by flow cytometry and antibody based proteomic microarray) from stem cell associated genes and/or increased cell proliferation (detected by flow cytometry) could be detected in well-characterised, routinely collected cervical samples from high risk HPV+ve women. Both cytology and histology results were available for most samples with moderate to high grade abnormality. We found that stem cell associated proteins including human chorionic gonadotropin, the oncogene TP63 and the transcription factor SOX2 were upregulated in samples from women with CIN3 and that the stem cell related, cell surface, protein podocalyxin was detectable on cells in samples from a subset of women with CIN3. SOX2, TP63 and human gonadotrophin mRNAs were upregulated in high grade disease. Immunohistochemistry showed that SOX2 and TP63 proteins clearly delineated tumour cells in invasive squamous cervical cancer. Samples from women with CIN3 showed increased proliferating cells. We believe that these markers may be of use to develop triage tests for women with high grade cervical abnormality to distinguish those who may progress to cancer from those who may be treated more conservatively.
| S-EPMC4274002 | biostudies-literature
Project description:Pancreatic ductal adenocarcinoma (PDA) is characterized by epithelial mutations in KRAS and prominent tumor-associated inflammation, including macrophage infiltration. But knowledge of early interactions between neoplastic epithelium and macrophages in PDA carcinogenesis is limited. Using a pancreatic organoid model, we found that the expression of mutant KRAS in organoids increased (i) ductal to acinar gene expression ratios, (ii) epithelial cells proliferation and (iii) colony formation capacity in vitro, and endowed pancreatic cells with the ability to generate neoplastic tumors in vivo. KRAS mutations induced a protumorigenic phenotype in macrophages. Altered macrophages decreased epithelial pigment epithelial derived factor (PEDF) expression and induced a cancerous phenotype. We validated our findings using annotated patient samples from The Cancer Genome Atlas (TCGA) and in our human PDA specimens. Epithelium-macrophage cross-talk occurs early in pancreatic carcinogenesis where KRAS directly induces cancer-related phenotypes in epithelium, and also promotes a protumorigenic phenotype in macrophages, in turn augmenting neoplastic growth.
| S-EPMC6128758 | biostudies-literature