Non-neoplastic Pancreatic Tissues Research Articles

Expression profiles of MUC5AC glycoforms in neoplastic and non-neoplastic pancreatic tissue.

e16008 Background: MUC5AC, secretory mucin, exists in two major glycoforms, heavily-glycosylated mature (MM) and less-glycosylated immature (IM) isoforms. Prior IM-based tissue expression studies could not establish the clinical significance of MUC5AC in pancreatic ductal adenocarcinoma (PDA). Despite having strong pre-clinical evidence of MM’s role in local invasion, metastasis, and drug (gemcitabine) resistance, its impact on PDA outcomes is unclear. In this study, for the first time, we examined the differential expression of MM and IM by immunohistochemistry in primary PDA (pPDA), metastatic PDA (mPDA), normal pancreatic tissue adjacent to tumor (NAJ), neuroendocrine tumors (NET), Pancreatitis (P), normal pancreas (N) using tissue microarrays (TMA). Methods: Commercially available TMA (PA2081c, tissuearray.com, Derwood, MD) constructed from 96 patients, including 38 pPDA (14-stage 1, 22-Stage 2, and 2-stage 3), 5 mPDA, 24 NAJ, 11 NET, 8 P and 10 N was used in this study. Two separate 1 mm cores represented each case. Immunohistochemistry for MUC5AC was performed using CHL2 clone (ab77576, abcam, Boston, MA) for the IM isoform and 45M1 clone (ab369, abcam, Boston, MA) for the MM isoform. The immunostains were optimized as per the manufacturer's recommendations using appropriate controls. The sections are evaluated for the intensity of expression (0-3) and the percentage of reactive cells, and an H-score is derived from the product of these measurements. Cases are categorized as having negative/weak (score <10) or positive (score >10) expression. For every positive case, the pattern of expression in terms of Apical (Ap), cytoplasmic (Cy), and extracellular (EC) expression was recorded. Results: MUC5AC (MM and IM) is not expressed in N, NAJ, and P. MM expression is only noted in 44% of PDAs (19/43; 18 pPDA and 1 omental mPDA lesion). Three different expression patterns were noted, including Ap (63%), Cy (84%), and EC (47%). IM expression was detected in 60% of PDAs (26/43, 25 pPDA and omental mPDA lesion) and 18% NET (2/11). IM expression was noted in cases with EC MM expression (9/43, 21%), suggesting that IM was further glycosylated to MM and expressed extracellularly in some patients. MM and MM were co-expressed in 40% of PDA (17/43). Liver and abdomen metastatic lesions in the TMA did not express IM or MM. Pertinent clinical information was not available to study the impact of MM’s expression on PDA outcomes. Conclusions: Our study shows that MUC5AC is primarily expressed in PDAs and can be a useful biomarker. Larger studies are ongoing to correlate tissue expression patterns in PDAs for evidence of any association with early recurrence or treatment failure. Preliminary data suggests that only MM isoform is expressed extracellularly and could be detected in patient serum and serve as a potential non-invasive biomarker for treatment selection (for gemcitabine resistance) and monitor the response in certain cases.

Tumor metabolic alterations after neoadjuvant chemoradiotherapy predict postoperative recurrence in patients with pancreatic cancer.

We investigated the metabolic changes in pancreatic ductal adenocarcinoma to identify the mechanisms of treatment response of neoadjuvant chemoradiation therapy. Frozen tumor and non-neoplastic pancreas tissues were prospectively obtained from 88 patients with pancreatic ductal adenocarcinoma who underwent curative-intent surgery. Sixty-two patients received neoadjuvant chemoradiation therapy and 26 patients did not receive neoadjuvant therapy (control group). Comprehensive analysis of metabolites in tumor and non-neoplastic pancreatic tissue was performed by capillary electrophoresis-mass spectrometry. Capillary electrophoresis-mass spectrometry detected 90 metabolites for analysis among more than 500 ionic metabolites quantified. There were significant differences in 27 tumor metabolites between the neoadjuvant chemoradiation therapy and control groups. There were significant differences in eight metabolites [1-MethylnNicotinamide, Carnitine, Glucose, Glutathione (red), N-acetylglucosamine 6-phosphate, N-acetylglucosamine 1-phosphate, UMP, Phosphocholine] between good responder and poor responder for neoadjuvant chemoradiation therapy. Among these metabolites, phosphocholine, Carnitine and Glutathione were associated with recurrence-free survival only in the neoadjuvant chemoradiation therapy group. Microarray confirmed marked gene suppression of choline transporters [CTL1-4 (SLC44A1-44A4)] in pancreatic ductal adenocarcinoma tissue of neoadjuvant chemoradiation therapy group. The present study identifies several important metabolic consequences and potential neoadjuvant chemoradiation therapy targets in pancreatic ductal adenocarcinoma. Choline metabolism is one of the key pathways involved in recurrence of the patients with pancreatic ductal adenocarcinoma who received neoadjuvant chemoradiation therapy.

Inhibitory Response to CK II Inhibitor Silmitasertib and CDKs Inhibitor Dinaciclib Is Related to Genetic Differences in Pancreatic Ductal Adenocarcinoma Cell Lines.

Casein kinase II (CK2) and cyclin-dependent kinases (CDKs) frequently interact within multiple pathways in pancreatic ductal adenocarcinoma (PDAC). Application of CK2- and CDK-inhibitors have been considered as a therapeutic option, but are currently not part of routine chemotherapy regimens. We investigated ten PDAC cell lines exposed to increasing concentrations of silmitasertib and dinaciclib. Cell proliferation, metabolic activity, biomass, and apoptosis/necrosis were evaluated, and bioinformatic clustering was used to classify cell lines into sensitive groups based on their response to inhibitors. Furthermore, whole exome sequencing (WES) and RNA sequencing (RNA-Seq) was conducted to assess recurrent mutations and the expression profile of inhibitor targets and genes frequently mutated in PDAC, respectively. Dinaciclib and silmitasertib demonstrated pronounced and limited cell line specific effects in cell death induction, respectively. WES revealed no genomic variants causing changes in the primary structure of the corresponding inhibitor target proteins. RNA-Seq demonstrated that the expression of all inhibitor target genes was higher in the PDAC cell lines compared to non-neoplastic pancreatic tissue. The observed differences in PDAC cell line sensitivity to silmitasertib or dinaciclib did not depend on target gene expression or the identified gene variants. For the PDAC hotspot genes kirsten rat sarcoma virus (KRAS) and tumor protein p53 (TP53), three and eight variants were identified, respectively. In conclusion, both inhibitors demonstrated in vitro efficacy on the PDAC cell lines. However, aberrations and expression of inhibitor target genes did not appear to affect the efficacy of the corresponding inhibitors. In addition, specific aberrations in TP53 and KRAS affected the efficacy of both inhibitors.

Prevalence of histological features resembling autoimmune pancreatitis in neoplastic pancreas resections.

Types 1 and 2 autoimmune pancreatitis (AIP) can mimic pancreatic neoplasia. Due to the small quantity of tissue in mass-targeted pancreas biopsies, inflammatory features may raise the differential of AIP. However, the frequency of AIP-like histology in neoplastic pancreas is not well characterised. Therefore, the specificity of inflammatory lesions on biopsy with respect to the diagnosis of AIP is uncertain. Neoplastic pancreas resections performed at our institution between 2008 and 2019 were retrospectively reviewed. Features of AIP types 1 and 2 were assessed in the non-neoplastic areas. If features of immunoglobulin (Ig)G4-associated AIP were seen, IgG4 immunohistochemistry was performed. We identified 163 neoplastic pancreas resections. Of these, 34 had one or more types of inflammatory lesions in non-neoplastic pancreatic tissue. Dense lymphoplasmacytic inflammation mimicking type 1 AIP was found in six cases with mild to moderately increased IgG4-positive plasma cells. Neutrophilic infiltrates in small intralobular ducts were found in 20 cases. Mild extralobular ductitis or duct microabscess was found in 10 specimens. Marked neutrophilic duct destruction that resembled granulocytic epithelial lesions was found in 12 cases. Some cases showed multiple features. Approximately 20% of neoplastic pancreas resections showed focal areas that could raise the differential of AIP. More cases showed neutrophilic predominant inflammation as seen in type 2 autoimmune pancreatitis, compared to dense lymphoplasmacytic infiltrates seen in type 1 AIP. Pathologists must be cautious when making a diagnosis of AIP on biopsy tissue based on histological findings alone.

New Pancreatic Cancer Biomarkers eIF1, eIF2D, eIF3C and eIF6 Play a Major Role in Translational Control in Ductal Adenocarcinoma.

Pancreatic cancer is one of the deadliest forms of cancer and ranks among the leading causes of cancer-related death worldwide. The most common histological type is ductal adenocarcinoma (PDAC), accounting for approximately 95% of cases. Deregulation of protein synthesis has been found to be closely related to cancer. The rate-limiting step of translation is initiation, which is regulated by a broad range of eukaryotic translation initiation factors (eIFs). Human PDAC samples were biochemically analyzed for the expression of various eIF subunits on the protein level (immunohistochemistry, immunoblot analyses) in 174 cases of PDAC in comparison with non-neoplastic pancreatic tissue (n=10). Our investigation revealed a significant down-regulation of four specific eIF subunits, namely eIF1, eIF2D, eIF3C and eIF6. Concomitantly, the protein (immunoblot) levels of eIF1, eIF2D, eIF3C and eIF6 were reduced in PDAC samples as compared with non-neoplastic pancreatic tissue. Members of the eIF family are of relevance in pancreatic tumor biology and may play a major role in translational control in PDAC. Consequently, they might be useful as potential new biomarkers and therapeutic targets in PDAC.

High methylation levels of PCDH10 predict poor prognosis in patients with pancreatic ductal adenocarcinoma

BackgroundPancreatic ductal adenocarcinoma (PDAC) is one of the most lethal malignancies and is not a clinically homogeneous disease, but subsets of patients with distinct prognosis and response to therapy can be identified by genome-wide analyses. Mutations in major PDAC driver genes were associated with poor survival. By bioinformatics analysis, we identified protocadherins among the most frequently mutated genes in PDAC suggesting an important role of these genes in the biology of this tumor. Promoter methylation of protocadherins has been suggested as a prognostic marker in different tumors, but in PDAC this epigenetic modification has not been extensively studied. Thus, we evaluated whether promoter methylation of three frequently mutated protocadherins, PCDHAC2, PCDHGC5 and PCDH10 could be used as survival predictors in PDAC patients.MethodsDNA extracted from 23 PDACs and adjacent non-neoplastic pancreatic tissues were bisulfite treated. Combined Bisulfite Restriction Analysis (COBRA) coupled to denaturing high-performance liquid chromatography (dHPLC) detection and bisulfite genomic sequencing (BGS) were used to determine the presence of methylated CpG dinucleotides in the promoter amplicons analyzed.ResultsIn an exploratory analysis, two protocadherins showed the same pattern of CpG methylation in PDAC and adjacent non-neoplastic pancreatic tissues: lack of methylation for PCDHAC2, complete methylation for PCDHGC5. Conversely, the third protocadherin analyzed, PCDH10, showed a variable degree of CpG methylation in PDAC and absence of methylation in adjacent non-neoplastic pancreatic tissues. At Kaplan–Meier analysis, high levels of PCDH10 methylation defined according to the receiver operating characteristic (ROC) curve analysis were significantly associated with worse progression-free survival (PFS) rates (P = 0.008), but not with overall survival (OS). High levels of PCDH10 methylation were a prognostic factor influencing PFS (HR = 4.0: 95% CI, 1.3–12.3; P = 0.016), but not the OS.ConclusionsIn this study, we show for the first time that the methylation status of PCDH10 can predict prognosis in PDAC patients with a significant impact on the outcome in terms of progression-free survival. High levels of PCDH10 promoter methylation could be useful to identify patients at high risk of disease progression, contributing to a more accurate stratification of PDAC patients for personalized clinical management.

Dysregulation of KRAS signaling in pancreatic cancer is not associated with KRAS mutations and outcome.

Pancreatic ductal adenocarcinoma (PDAC) is a tumor with a poor prognosis, and no targeted therapy is currently available. The aim of the present study was to investigate the prognostic significance of the expression of V-Ki-ras2 Κirsten rat sarcoma viral oncogene homolog (KRAS), downstream signaling pathway genes and the association with clinical characteristics in PDAC patients undergoing radical surgery. Tumors and adjacent non-neoplastic pancreatic tissues were examined in 45 patients with histologically verified PDAC. KRAS and B-Raf proto-oncogene, serine/threonine kinase (BRAF) gene mutation analysis was performed using the KRAS/BRAF/phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α array. The transcript profile of 52 KRAS downstream signaling pathway genes was assessed using quantitative-polymerase chain reaction. KRAS mutation was detected in 80% of cases. The genes of four signaling pathways downstream of KRAS, including the phosphoinositide 3-kinase/3-phosphoinositide-dependent protein kinase 1/V-akt murine thymoma viral oncogene homolog 1, RAL guanine nucleotide exchange factor, Ras and Rab interactor 1/ABL proto-oncogene-1, non-receptor tyrosine kinase, and RAF proto-oncogene serine/threonine-protein kinase/mitogen-activated protein kinase pathways, exhibited differential expression in PDAC compared with that in the adjacent normal tissues. However, no significant differences in expression were evident between patients with KRAS-mutated and wild-type tumors. The expression of KRAS downstream signaling pathways genes did not correlate with angioinvasion, perineural invasion, grade or presence of lymph node metastasis. Additionally, the presence of KRAS mutations was not associated with overall survival. Among the KRAS downstream effective signaling pathways molecules investigated, only v-raf-1 murine leukemia viral oncogene homolog 1 expression was predictive of prognosis. Overall, KRAS mutation is present in the majority of cases of PDAC, but is not associated with changes in the expression of KRAS downstream signaling pathways and the clinical outcome. This may partly explain the failure of KRAS-targeted therapies in PDAC.

CD13hi Neutrophil-like myeloid-derived suppressor cells exert immune suppression through Arginase 1 expression in pancreatic ductal adenocarcinoma

ABSTRACTPerineural invasion and immunosuppressive tumor microenvironment are the distinct features of pancreatic ductal adenocarcinoma (PDAC). Heterogeneous myeloid-derived suppressor cells (MDSCs) are potent suppressors of antitumor immunity, posing obstacles for cancer immunotherapy. Increasing evidences have demonstrated the accumulation of MDSCs in PDAC patients. However, the role of MDSCs in perineural invasion of PDAC and the existence of novel MDSC subsets during PDAC remain unclear. This study found that lymphocytic perineural cuffs were frequently present in chronic pancreatitis (CP) tissues and adjacent non-neoplastic pancreatic tissues (ANPTs), but not in PDAC with perineural invasion. Meanwhile, we found that neutrophil-like MDSCs (nMDSCs), but not monocyte-like MDSCs (mMDSCs), were significantly increased in PBMCs and tumor tissues of PDAC patients. Further observation identified two distinct subsets of nMDSCs, CD13hi and CD13low nMDSCs in PDAC patients, which have not been reported previously. Despite a similar morphology, CD13hi nMDSCs expressed higher levels of CD11b, CD33, CD16 and arginase 1 but lower levels of CD66b than CD13low nMDSCs. Importantly, CD13hi MDSCs, compared with CD13low nMDSCs, more effectively suppressed alloreactive T cell responses via an arginase-1-related mechanism. After tumor resection, the circulating CD13hi nMDSCs were decreased markedly. PDAC patients with more CD13hi nMDSCs had a shorter overall survival than those with less CD13hi nMDSCs. To conclude, we identified two novel MDSC subsets with different characteristics and functions in PDAC, demonstrated the association of the two MDSC subsets with cancer progression, and explored their roles in perineural invasion and immune escape of PDAC.

The detection of tumor location and lymph node metastasis by aberrant NXPH1 and NXPH2 expressions in pancreatic ductal adenocarcinomas.

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive disease associated with a poor prognosis and high morbidity. Early diagnosis and complete tumor removal are still the principal factors extending life expectancy in PDAC patients. Here, the relationship of neurexophillin 1 (NXPH1) and NXPH2 expressions with clinicopathological parameters of PDAC was evaluated. Immunohistochemical analysis of NXPH1 and NXPH2 was performed in one tissue microarray of 96 surgical specimens, including normal pancreatic duct tissue (n = 5), PDACs at various stages of differentiation (n = 77), and pancreatic neuroendocrine tumors (n = 14). The intensity of both NXPH1 and NXPH2 staining was weak in only a small proportion of benign pancreatic ductal epithelial cells and was significantly higher in most PDAC specimens than in non-neoplastic pancreatic tissue specimens. However, no correlation of the expression of these PDAC biomarkers with tumor grades, T, N, and American Joint Committee on Cancer (AJCC) pathologic stages was established. Contrary to our expectation, the immunohistochemical results of NXPH1 and NXPH2 were inversely correlated with N stage in PDAC. NXPH1 and NXPH2 as PDAC biomarkers may be used to identify patients with this tumor, help delineate appropriate surgical margins, and identify lymph node metastasis in imaging studies.

The role of S100P and IMP3 in the cytologic diagnosis of pancreatic adenocarcinoma

PurposeThe aim of this study was to assess the role of the two markers, S100P and IMP3, in differentiating between pancreatic ductal adenocarcinoma (PDA) and non-neoplastic pancreatic tissue in (fine needle aspiration cytology) FNAC. Patients and methodsThis is a retrospective study that included 72 cases presented with pancreatic mass, where endoscopic guided FNAC was taken from pancreatic lesions. The final histopathologic diagnosis was considered the gold standard. Cell blocks were stained with anti S100P, and IMP3. Nuclear immunoreactivity with or without cytoplasmic staining for the first marker, and cytoplasmic staining for the second marker was considered specific.Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and total accuracy of the two markers, as well as the combined accuracy of both markers were calculated. ResultsS100P achieved 96.4% sensitivity, 93.3% specificity, 98.2% PPV, 87.5% NPV and 95.8% total accuracy, while IMP3 achieved 91.2% sensitivity, 86.7% specificity, 96.2% PPV, 72.2% NPV and 90.3% total accuracy for PDA.Both markers showed a total combined accuracy of 89%.S100P showed strong and diffuse staining pattern in most of cases, while the staining pattern for IMP3 was moderate and focal in most of cases. ConclusionBoth markers were sensitive and specific for diagnosis of PDA. The staining pattern for S100P was easier to evaluate than IMP3.

Hedgehog pathway overexpression in pancreatic cancer is abrogated by new-generation taxoid SB-T-1216.

The Hedgehog pathway is one of the major driver pathways in pancreatic ductal adenocarcinoma. This study investigated prognostic importance of Hedgehog signaling pathway in pancreatic cancer patients who underwent a radical resection. Tumors and adjacent non-neoplastic pancreatic tissues were obtained from 45 patients with histologically verified pancreatic cancer. The effect of experimental taxane chemotherapy on the expression of Hedgehog pathway was evaluated in vivo using a mouse xenograft model prepared using pancreatic cancer cell line Paca-44. Mice were treated by experimental Stony Brook Taxane SB-T-1216. The transcript profile of 34 Hedgehog pathway genes in patients and xenografts was assessed using quantitative PCR. The Hedgehog pathway was strongly overexpressed in pancreatic tumors and upregulation of SHH, IHH, HHAT and PTCH1 was associated with a trend toward decreased patient survival. No association of Hedgehog pathway expression with KRAS mutation status was found in tumors. Sonic hedgehog ligand was overexpressed, but all other downstream genes were downregulated by SB-T-1216 treatment in vivo. Suppression of HH pathway expression in vivo by taxane-based chemotherapy suggests a new mechanism of action for treatment of this aggressive tumor.

Identification of genes and pathways associated with pancreatic ductal adenocarcinoma by bioinformatics analyses.

This study aimed to explore the underlying genes and pathways associated with pancreatic ductal adenocarcinoma (PDAC) by bioinformatics analyses. Gene expression profile GSE43795 was downloaded from the Gene Expression Omnibus database. The differentially expressed genes (DEGs) between six PDAC and five non-neoplastic pancreatic tissue samples were analyzed using the limma package. Gene ontology (GO) and pathway enrichment analyses of DEGs were performed, followed by functional annotation and protein-protein interaction (PPI) network construction. Finally, the sub-network was identified and pathway enrichment analysis was performed on the contained DEGs. A total of 374 downregulated and 559 upregulated DEGs were identified. The downregulated DEGs were enriched in GO terms associated with digestion and transport and pathways related to metabolism, while the upregulated DEGs were enriched in GO terms associated with the cell cycle and mitosis and pathways associated with the occurrence of cancer including the cell cycle pathway. Following functional annotation, the oncogene pituitary tumor-transforming 1 (PTTG1) was upregulated. In the PPI network and sub-network, cell division cycle 20 (CDC20) and BUB1 mitotic checkpoint serine/threonine kinase B (BUB1B) were hub genes with high connectivity degrees. Additionally, DEGs in the sub-network including cyclin B1 (CCNB1) were mainly enriched in the cell cycle and p53 signaling pathways. In conclusion, the cell cycle and p53 signaling pathways may play significant roles in PDAC, and DEGs including CDC20, BUB1B, CCNB1 and PTTG1 may be potential targets for PDAC diagnosis and treatment.

Overexpression of β3 Chains of Laminin-332 is Associated With Clinicopathologic Features and Decreased Survival in Patients With Pancreatic Adenocarcinoma.

Background:Laminin-332 (LM-332, formerly termed laminin-5) is a heterotrimeric glycoprotein that promotes cellular adhesion and migration. The heterotrimer consists of an α3, a β3, and a γ2 chain. The aim of this investigation was to clarify the clinicopathologic significance of laminin-332β3 (LNβ3) chain expression and determine its influence on survival in pancreatic ductal adenocarcinoma.Materials and Methods:Quantitative real-time polymerase chain reaction was used to validate and detect the expression of LNβ3 mRNA in 37 pancreatic carcinoma tissue specimens and non-neoplastic pancreatic tissue samples. In addition, the protein expression of LNβ3 was detected by immunohistochemistry methods in 96 pancreatic carcinoma specimens and 90 non-neoplastic pancreatic tissues. We analyzed the association between immunohistochemically detected LNβ3 expression in pancreatic ductal adenocarcinoma and clinicopathologic characteristics. Survival curves were completed using the Kaplan-Meier method and compared using log-rank analysis.Results:Quantitative real-time polymerase chain reaction indicated that the relative value of LNβ3 mRNA was 1.427±1.554 and 1.423±1.439 by 2−Δ(ΔCt) in pancreatic carcinoma and non-neoplastic pancreatic tissues, respectively, values that were not statistically associated (P=0.991). Immunostaining for LNβ3 was expressed in all patients with pancreatic ductal adenocarcinoma. LNβ3 expression was related to differentiation (P=0.000) and advanced stage (P=0.034). Tumors with low expression of LNβ3 had a survival advantage compared with tumors that had high expression of LNβ3 (P=0.016). Multivariate analysis indicated that location is an independent predictor of overall survival, whereas other clinicopathologic characteristics such as tumor size, duodenal invasion, differentiation, extent of invasion, hepatic metastasis, and expression of LNβ3 were not.Conclusion:Our results suggest that LNβ3 expression may play a key role in the progression and prognosis of pancreatic ductal adenocarcinoma.

Distinct Protein Expression Profiles of Solid-Pseudopapillary Neoplasms of the Pancreas.

Solid-pseudopapillary neoplasm (SPN) is an uncommon pancreatic tumor with mutation in CTNNB1 and distinct clinical and pathological features. We compared the proteomic profiles of SPN to mRNA expression. Pooled SPNs and pooled non-neoplastic pancreatic tissues were examined with high-resolution mass spectrometry. We identified 329 (150 up-regulated and 179 down-regulated) differentially expressed proteins in SPN. We identified 191 proteins (58.1% of the 329 dysregulated proteins) with the same expression tendencies in SPN based on mRNA data. Many overexpressed proteins were related to signaling pathways known to be activated in SPNs. We found that several proteins involved in Wnt signaling, including DKK4 and β-catenin, and proteins that bind β-catenin, such as FUS and NONO, were up-regulated in SPNs. Molecules involved in glycolysis, including PKM2, ENO2, and HK1, were overexpressed in accordance to their mRNA levels. In summary, SPN showed (1) distinct protein expression changes that correlated with mRNA expression, (2) overexpression of Wnt signaling proteins and proteins that bind directly to β-catenin, and (3) overexpression of proteins involved in metabolism. These findings may help develop early diagnostic biomarkers and molecular targets.

Sonic hedgehog paracrine signaling activates stromal cells to promote perineural invasion in pancreatic cancer.

Pancreatic cancer is characterized by stromal desmoplasia and perineural invasion (PNI). We sought to explore the contribution of pancreatic stellate cells (PSC) activated by paracrine Sonic Hedgehog (SHH) in pancreatic cancer PNI and progression. In this study, the expression dynamics of SHH were examined via immunohistochemistry, real-time PCR, and Western blot analysis in a cohort of carcinomatous and nonneoplastic pancreatic tissues and cells. A series of in vivo and in vitro assays was performed to elucidate the contribution of PSCs activated by paracrine SHH signaling in pancreatic cancer PNI and progression. We show that SHH overexpression in tumor cells is involved in PNI in pancreatic cancer and is an important marker of biologic activity of pancreatic cancer. Moreover, the overexpression of SHH in tumor cells activates the hedgehog pathway in PSCs in the stroma instead of activating tumor cells. These activated PSCs are essential for the promotion of pancreatic cancer cell migration along nerve axons and nerve outgrowth to pancreatic cancer cell colonies in an in vitro three-dimensional model of nerve invasion in cancer. Furthermore, the coimplantation of PSCs activated by paracrine SHH induced tumor cell invasion of the trunk and nerve dysfunction along sciatic nerves and also promoted orthotropic xenograft tumor growth, metastasis, and PNI in in vivo models. These results establish that stromal PSCs activated by SHH paracrine signaling in pancreatic cancer cells secrete high levels of PNI-associated molecules to promote PNI in pancreatic cancer.

Characterization of gene expression and activated signaling pathways in solid-pseudopapillary neoplasm of pancreas

Solid-pseudopapillary neoplasm is an uncommon pancreatic tumor with distinct clinicopathologic features. Solid-pseudopapillary neoplasms are characterized by mutations in exon 3 of CTNNB1. However, little is known about the gene and microRNA expression profiles of solid-pseudopapillary neoplasms. Thus, we sought to characterize solid-pseudopapillary neoplasm-specific gene expression and identify the signaling pathways activated in these tumors. Comparisons of gene expression in solid-pseudopapillary neoplasm to pancreatic ductal carcinomas, neuroendocrine tumors, and non-neoplastic pancreatic tissues identified solid-pseudopapillary neoplasm-specific mRNA and microRNA profiles. By analyzing 1686 (1119 upregulated and 567 downregulated) genes differentially expressed in solid-pseudopapillary neoplasm, we found that the Wnt/β-catenin, Hedgehog, and androgen receptor signaling pathways, as well as genes involved in epithelial mesenchymal transition, are activated in solid-pseudopapillary neoplasms. We validated these results experimentally by assessing the expression of β-catenin, WIF-1, GLI2, androgen receptor, and epithelial–mesenchymal transition-related markers with western blotting and immunohistochemistry. Our analysis also revealed 17 microRNAs, especially the miR-200 family and miR-192/215, closely associated with the upregulated genes associated with the three pathways activated in solid-pseudopapillary neoplasm and epithelial mesenchymal transition. Our results provide insight into the molecular mechanisms underlying solid-pseudopapillary neoplasm tumorigenesis and its characteristic less epithelial cell differentiation than the other common pancreatic tumors.

Nuclear Death Receptor TRAIL-R2 Inhibits Maturation of Let-7 and Promotes Proliferation of Pancreatic and Other Tumor Cells

Tumor necrosis factor-related apoptosis inducing ligand (TRAIL-R1) (TNFRSF10A) and TRAIL-R2 (TNFRSF10B) on the plasma membrane bind ligands that activate apoptotic and other signaling pathways. Cancer cells also might have TRAIL-R2 in the cytoplasm or nucleus, although little is known about its activities in these locations. We investigated the functions of nuclear TRAIL-R2 in cancer cell lines. Proteins that interact with TRAIL-R2 initially were identified in pancreatic cancer cells by immunoprecipitation, mass spectrometry, and immunofluorescence analyses. Findings were validated in colon, renal, lung, and breast cancer cells. Functions of TRAIL-R2 were determined from small interfering RNA knockdown, real-time polymerase chain reaction, Drosha-activity, microRNA array, proliferation, differentiation, and immunoblot experiments. We assessed the effects of TRAIL-R2 overexpression or knockdown in human pancreatic ductal adenocarcinoma (PDAC) cells and their ability to form tumors in mice. We also analyzed levels of TRAIL-R2 in sections of PDACs and non-neoplastic peritumoral ducts from patients. TRAIL-R2 was found to interact with the core microprocessor components Drosha and DGCR8 and the associated regulatory proteins p68, hnRNPA1, NF45, and NF90 in nuclei of PDAC and other tumor cells. Knockdown of TRAIL-R2 increased Drosha-mediated processing of the let-7 microRNA precursor primary let-7 (resulting in increased levels of mature let-7), reduced levels of the let-7 targets (LIN28B and HMGA2), and inhibited cell proliferation. PDAC tissues from patients had higher levels of nuclear TRAIL-R2 than non-neoplastic pancreatic tissue, which correlated with increased nuclear levels of HMGA2 and poor outcomes. Knockdown of TRAIL-R2 in PDAC cells slowed their growth as orthotopic tumors in mice. Reduced nuclear levels of TRAIL-R2 in cultured pancreatic epithelial cells promoted their differentiation. Nuclear TRAIL-R2 inhibits maturation of the microRNA let-7 in pancreatic cancer cell lines and increases their proliferation. Pancreatic tumor samples have increased levels of nuclear TRAIL-R2, which correlate with poor outcome of patients. These findings indicate that in the nucleus, death receptors can function as tumor promoters and might be therapeutic targets.

Pancreatic intraepithelial neoplasia and histological changes in non‐neoplastic pancreas associated with neoadjuvant therapy in patients with pancreatic ductal adenocarcinoma

To study the histological changes in non-neoplastic pancreas and the effects on pancreatic intraepithelial neoplasia (PanIN) after neoadjuvant chemoradiation therapy (NCRT) for pancreatic ductal adenocarcinoma (PDAC). We reviewed the archival H&E slides from 218 patients with PDAC who completed NCRT and pancreaticoduodenectomy. Sixty-five patients who underwent pancreaticoduodenectomy for PDAC without NCRT were used as controls. Various histological features were reviewed and correlated with NCRT and survival. The NCRT group had lower densities of PanIN2 (P = 0.004) and PanIN3 (P = 0.02) than the control group. The extent of fibrosis, the frequency of neuroma-like nerve proliferation and the frequency of islet cell aggregation were significantly higher in the NCRT group than in the control group (P < 0.05). The intensity of inflammation was less in the NCRT group than in the control group (P = 0.02). In the NCRT group, patents with moderate to severe fibrosis or grade 2 inflammation had poorer survival than those with mild fibrosis (P = 0.04) or those with grade 0 or grade 1 inflammation (P = 0.003), respectively. Non-neoplastic pancreatic tissue from patients who received NCRT had a reduced density of high-grade PanIN lesions, more pancreatic fibrosis, and higher frequencies of neuroma-like nerve proliferation and islet cell aggregation, but less inflammation, compared to tissue from those who did not receive NCRT.

Clinicopathologic significance of immunostaining of α-thalassemia/mental retardation syndrome X-linked protein and death domain–associated protein in neuroendocrine tumors

α-Thalassemia/mental retardation syndrome X-linked protein (ATRX) and death domain-associated protein (DAXX) genes are tumor suppressors whose mutations have been identified in sporadic pancreatic neuroendocrine tumors as well as in patients with MEN1. However, it is unknown whether ATRX and DAXX alterations are specific for pancreatic neuroendocrine tumor. In addition, the association of ATRX/DAXX protein loss with tumor cell proliferation has not been examined. We, therefore, immunostained ATRX and DAXX in 10 gastric, 15 duodenal, 20 rectal, 70 pancreatic, and 22 pulmonary neuroendocrine tumors with 15 nonneoplastic pancreases and 27 pancreatic adenocarcinomas to elucidate the site-specific roles of ATRX/DAXX abnormalities. At least 1 loss of ATRX and DAXX immunoreactivity was detected in all neuroendocrine tumor cases but not in any of nonneoplastic pancreatic tissues or pancreatic adenocarcinomas. The loss of DAXX protein was correlated with the Ki-67 index (ATRX, P = .904; DAXX, P = .044). The status of DAXX immunoreactivity correlated positively with World Health Organization histologic grade (P = .026). These results suggest that the status of ATRX or DAXX protein loss in neuroendocrine tumor differed among the organs in which these tumors arose, and these proteins may play site-specific roles in the development of these tumors.

The association between the expression of solute carrier transporters and the prognosis of pancreatic cancer

The aim of this study was to investigate the prognostic significance of fourteen anticancer drug-relevant solute carrier transporters (SLCs) in pancreatic cancer in the context of clinical-pathological characteristics and the KRAS mutation status of tumors. Tumors and non-neoplastic pancreatic tissues were obtained from 32 histologically verified patients with pancreatic ductal adenocarcinoma. The transcript profile of SLCs was assessed using quantitative real-time PCR. KRAS mutations in exon 2 were assessed by high-resolution melting analysis and confirmed by sequencing. SLC22A3 and SLC22A18 were upregulated and SLC22A1, SLC22A2, SLC22A11, SLC28A1, SLC28A3 and SLC29A1 were downregulated when compared with non-neoplastic pancreatic tissues. Moreover, significantly lower levels of SLC22A1, SLC22A11 and SLC29A1 were found in tumors with angioinvasion. There was also a significantly higher transcript level of SLC28A1 in tumors with regional lymph nodes affected by metastasis. The study found that a high expression of SLC28A1 was significantly associated with poor overall survival in unselected patients. In contrast, a high expression of SLC22A3 or SLC29A3 was significantly associated with longer overall survival in patients treated with nucleoside analogs. Protein expression of SLC22A1, SLC22A3 and SLC29A3 in tumor tissues of patients with pancreatic carcinoma was observed by immunoblotting for the first time. Finally, SLC levels were not found to be associated with KRAS mutation status in exon 2. This study identified a number of associations of transcript levels of SLCs with prognosis of pancreatic cancer patients.