Renalase is a novel tissue and serological biomarker in pancreatic ductal adenocarcinoma

Dysregulated expression of the secretory protein renalase can promote pancreatic ductal adenocarcinoma (PDAC) growth in animal models. We characterized renalase expression in premalignant and malignant PDAC tissue and investigated whether plasma renalase levels corresponded to clinical PDAC characteristics. Renalase immunohistochemistry was used to determine the presence and distribution of renalase in normal pancreas, chronic pancreatitis, PDAC precursor lesions, and PDAC tissues. Associations between pretreatment plasma renalase and PDAC clinical status were assessed in patients with varied clinical stages of PDAC and included tumor characteristics, surgical resection in locally advanced/borderline resectable PDAC, and overall survival. Data were retrospectively obtained and correlated using non-parametric analysis. Little to no renalase was detected by histochemistry in the normal pancreatic head in the absence of abdominal trauma. In chronic pancreatitis, renalase immunoreactivity localized to peri-acinar spindle-shaped cells in some samples. It was also widely present in PDAC precursor lesions and PDAC tissue. Among 240 patients with PDAC, elevated plasma renalase levels were associated with worse tumor characteristics, including greater angiolymphatic invasion (80.0% vs. 58.1%, p = 0.012) and greater node positive disease (76.5% vs. 56.5%, p = 0.024). Overall survival was worse in patients with high plasma renalase levels with median follow-up of 27.70 months vs. 65.03 months (p < 0.001). Renalase levels also predicted whether patients with locally advanced/borderline resectable PDAC underwent resection (AUC 0.674; 95%CI 0.42–0.82, p = 0.04). Overall tissue renalase was increased in both premalignant and malignant PDAC tissues compared to normal pancreas. Elevated plasma renalase levels were associated with advanced tumor characteristics, decreased overall survival, and reduced resectability in patients with locally advanced/borderline resectable PDAC. These studies show that renalase levels are increased in premalignant pancreatic tissues and that its levels in plasma correspond to the clinical behavior of PDAC.

Dysregulation of miRNAs Targeting the IGF-1R Pathway in Pancreatic Ductal Adenocarcinoma

Background: Pancreatic ductal adenocarcinoma (PDAC), the most prevalent neoplastic lethal pancreatic disease, has a poor prognosis and an increasing incidence. The insulin-like growth factor-1 receptor (IGF-1R) signaling pathway is considered to be a contributing factor to the progression, metastasis, and therapy resistance of PDAC. Currently available treatment options for PDAC are limited, but microRNAs (miRNAs) may represent a new therapeutic strategy for targeting genes involved in the IGF-1R signaling pathway. Method: We investigated the expression levels of 21 miRNAs involved in the IGF-1R signaling pathway in pancreatic tissue from 38 patients with PDAC and 11 controls (five patients with chronic pancreatitis and six patients with normal pancreatic tissue). Results: We found 19 differentially expressed miRNAs between the PDAC cases and the controls. In particular, miR-100-5p, miR-145-5p, miR-29c-3p, miR-9-5p, and miR-195-5p were exclusively downregulated in PDAC tissue but not in chronic pancreatitis or normal pancreatic tissues; both control types presented similar levels. We also identified miR-29a-3p, miR-29b-3p, and miR-7-5p as downregulated miRNAs in PDAC tissues as compared with normal tissues but not with pancreatitis tissues. Conclusions: We identified a panel of miRNAs that could represent putative therapeutic targets for the development of new miRNA-based therapies for PDAC.

The Landscape of Microbial Composition and Associated Factors in Pancreatic Ductal Adenocarcinoma Using RNA-Seq Data

Recent research studies on interrogation of the tumor microbiome (including bacteria, viruses, and fungi) have yielded important insights into the role of microbes in carcinogenesis, therapeutic responses, and resistance. Once thought to be a sterile organ, a number of studies have showed the presence of microbes within this organ in PDAC status. A microbiome–pancreas axis for PDAC (pancreatic ductal adenocarcinoma) carcinogenesis is proposed. However, the microbial composition of localized PDAC tissue is still unclear. The associations between microbiome and PDAC reported in previous studies were detected in an indirect way, which mostly used samples from stool, oral saliva, and intestinal samples. This study integrated 582 samples derived from PDAC tissues across four datasets and presented a landscape of tumor microbiome at the genus level in PDAC based on remining of RNA-Seq data. On average, there are hundreds of genera distributed in the PDAC tissue, and dozens of core microbiota were identified by PDAC tissue. The pan-microbiome of PDAC tissue was also estimated, which might surpass 2,500 genera. In addition, sampling sites (stroma vs. epithelium) and tissue source (human tissue vs. PDX) were found to have great effects on the microbial composition of PDAC tissue, but not the traditional risk factors (sex and age). It is the first study to systematically focus on exploring the microbial composition of PDAC tissue and is helpful to have a deep understanding of tumor microbiome. The identified specific taxa might be potential biomarkers for follow-up research studies.

Identification of the Neurokinin-1 Receptor as Targetable Stratification Factor for Drug Repurposing in Pancreatic Cancer

The SP/NK1R-complex plays an important role in tumor proliferation. Targeting of the neurokinin-1 receptor in previous studies with its antagonist aprepitant (AP) resulted in anti-tumoral effects in colorectal cancer and hepatoblastoma. However, there is still a lack of knowledge regarding its effects on pancreatic cancer. Therefore, we treated human pancreatic ductal adenocarcinoma (PDAC) cell lines (Capan-1, DanG, HuP-T3, Panc-1, and MIA PaCa-2) and their cancer stem cell-like cells (CSCs) with AP and analyzed functional effects by MTT-, colony, and sphere formation assays, respectively; moreover, we monitored downstream mechanisms by flow cytometry. NK1R inhibition resulted in dose-dependent growth reduction in both CSCs and non-CSCs without induction of apoptosis in most PDAC cell lines. More importantly, we identified striking AP dependent cell cycle arrest in all parental cells. Furthermore, gene expression and the importance of key genes in PDAC tumorigenesis were analyzed combining RT-qPCR in eight PDAC cell lines with publicly available datasets (TCGA, GEO, CCLE). Surprisingly, we found a better overall survival in patients with high NK1R levels, while at the same time, NK1R was significantly decreased in PDAC tissue compared to normal tissue. Interestingly, there is currently no differentiation between the isoforms of NK1R (truncated and full; NK1R-tr and -fl) in any of the indicated public transcriptomic records, although many publications already emphasize on important regulatory differences between the two isoforms of NK1R in many cancer entities. In conclusion, analysis of splice variants might potentially lead to a stratification of PDAC patients for NK1R-directed therapies. Furthermore, we presume PDAC patients with high expressions of NK1R-tr might benefit from treatment with AP to improve chemoresistance. Therefore, analysis of splice variants might potentially lead to a stratification of PDAC patients for NK1R-directed therapies.

Hyaluronan heterogeneity in pancreatic ductal adenocarcinoma, primary tumors, and sites of metastasis.

e16231 Background: Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers with an estimated five-year survival rate of 10%. The dense desmoplastic stroma in PDAC contributes to its aggressive nature and treatment resistance. Among the components comprising the stroma, hyaluronan (HA) has been demonstrated to play a critical role in tumor progression and survival. Previous preliminary studies have suggested differences in HA expression in primary and metastatic foci in PDAC. However, the effects of treatment and location of HA expression as well as the role of CD44, a known receptor for HA, on HA as a biomarker signature remain unknown. Thus, we investigated the potential of HA as a biomarker in primary PDAC and metastases. Methods: PDAC tissue from primary (n = 43) and metastatic (n = 66) sites were obtained from Cedars-Sinai Medical Center along with associated clinical data. Tissue slides were stained with H&E, HA using a histochemical assay, and CD44 by immunohistochemistry. HA staining was scored according to the proportion of stromal staining at an intensity greater than the background stroma. HA status was defined as ≥ 50% staining being HA high and < 50% as being HA low. CD44 staining was recorded as an H-score (percentage of tumor cells staining multiplied by intensity of staining on a scale from 0 to 3). Associations between HA levels and the requested variables were examined with t-test, Wilcoxon rank-sum test, Chi-squared test, Fisher’s exact test, or Cox regression model where appropriate. Kaplan-Meier curves were created to assess progression free survival and overall survival. Analyses were performed using SAS 9.4 with two-sided tests and a significance level of 0.05. Results: HA score was significantly higher in primary PDAC tissue compared to sites of metastases (p = 0.0148). Within the metastases, HA score was significantly higher in liver metastasis compared to other sites of metastasis (p = 0.0478). In the liver metastasis tissue, HA score trended lower in patients with previously treated tissue compared to treatment naïve tissue (p = 0.0622). In the treatment naive liver metastasis cohort, patients with HA high status had decreased progression free survival and overall survival compared to patients with HA low status (p = 0.0032 and p = 0.0478, respectively). Using HA score and CD44 in a Cox regression model demonstrated that for every one unit increase in HA score, the risk for recurrence/progression increased by 4.4% at any fixed point in time, adjusting for CD44 score (p = 0.0049). Conclusions: HA score is variable between primary PDAC, PDAC metastatic to the liver, and PDAC metastatic to other sites. Within liver metastases, patients with HA high status had decreased progression free survival and overall survival compared to patients with HA low status. HA levels can serve as a potential biomarker to guide pancreatic cancer treatments and trial design for agents targeting the stroma.

PIVKA-II: A biomarker for diagnosing and monitoring patients with pancreatic adenocarcinoma

Background Pancreatic adenocarcinoma (PDAC) is an incurable cancer without adequate tumor markers. Our previous study has showed a better diagnostic performance of Protein Induced by Vitamin K Absence II (PIVKA-II) compared to currently used PDAC biomarkers. To corroborate our previous data with a larger sample size and to assess a possible role of PIVKA-II in predicting surgical success. Additionally, to further evaluate the hypothesis of a direct PIVKA-II production by PDAC cells, we examined PIVKA-II tissue expression in a case of PDAC using immunofluorescence. Methods We enrolled 76 newly diagnosed PDAC patients and selected 11 patients to determine PIVKA-II levels also after surgical resection. An immunofluorescence (IF) study of PIVKA-II tissue expression was carried out in one of them. PIVKA-II serum values were measured by chemiluminescent enzyme immunoassay method (CLEIA) on LUMIPULSE G1200 (Fujirebio-Europe, Belgium). Results PIVKA-II serum levels were above the cut-off at baseline in 71 patients (94%) with a median value of 464 mAU/Ml (range 27–40783 mAU/mL); the sensitivity and specificity were 78.67% and 90.67% respectively. Patients with pre-operative PIVKA-II positivity showed a significant decrease (P < 0.015) of median PIVKA-II serum concentrations after surgery: 820 (91–40783) mAU/mL at diagnosis vs 123 (31–4666) mAU/mL post-operatively. IF assay on PDAC sections demonstrated PIVKA-II expression in cancer cells. Conclusion These data are the first showing a decreased PIVKA-II serum levels after surgery in PDAC patients and reporting PIVKA-II expression in PDAC tissue. Further studies are needed to confirm these findings and to determine PIVKA-II usefulness in diagnosing and monitoring PDAC patients.

Identification, Validation, and Utilization of Immune Cells in Pancreatic Ductal Adenocarcinoma Based on Marker Genes

The immune response affects tumor biological behavior and progression. The specific immune characteristics of pancreatic ductal adenocarcinoma (PDAC) can determine the metastatic abilities of cancerous cells and the survival of patients. Therefore, it is important to characterize the specific immune landscape in PDAC tissue samples, and the effect of various types of therapy on that immune composition. Previously, a set of marker genes was identified to assess the immune cell composition in different types of cancer tissue samples. However, gene expression and subtypes of immune cells may vary across different types of cancers. The aim of this study was to provide a method to identify immune cells specifically in PDAC tissue samples. The method is based on defining a specific set of marker genes expressed by various immune cells in PDAC samples. A total of 90 marker genes were selected and tested for immune cell type-specific definition in PDAC; including 43 previously used, and 47 newly selected marker genes. The immune cell-type specificity was checked mathematically by calculating the “pairwise similarity” for all candidate genes using the PDAC RNA-sequenced dataset available at The Cancer Genome Atlas. A set of 55 marker genes that identify 22 different immune cell types for PDAC was created. To validate the method and the set of marker genes, an independent mRNA expression dataset of 24 samples of PDAC patients who received various types of (neo)adjuvant treatments was used. The results showed that by applying our method we were able to identify PDAC specific marker genes to characterize immune cell infiltration in tissue samples. The method we described enabled identifying different subtypes of immune cells that were affected by various types of therapy in PDAC patients. In addition, our method can be easily adapted and applied to identify the specific immune landscape in various types of tissue samples.

Renalase is a novel tissue and serological biomarker in pancreatic ductal adenocarcinoma

Dysregulated expression of the secretory protein renalase (RNLS) can promote pancreatic ductal adenocarcinoma (PDAC) growth in animal models. We characterized RNLS expression in premalignant and malignant PDAC tissue and investigated whether plasma RNLS levels corresponded to clinical PDAC characteristics. RNLS immunohistochemistry was used to determine the presence and distribution of RNLS in normal pancreas, chronic pancreatitis, PDAC precursor lesions, and PDAC tissues. Associations between pretreatment plasma RNLS and PDAC clinical status were assessed in patients with varied clinical stages of PDAC and included tumor characteristics, surgical resection in locally advanced/borderline resectable PDAC, and overall survival. Data were retrospectively obtained and correlated using non-parametric analysis. Mild to no RNLS was detected by histochemistry in the normal pancreas in the absence of abdominal trauma. In chronic pancreatitis, RNLS immunoreactivity localized to peri-acinar spindle-shaped cells in some samples. It was also widely present in PDAC precursor lesions and PDAC tissue. Among 240 patients with PDAC, elevated plasma RNLS levels were associated with worse tumor characteristics, including greater angiolymphatic invasion (80.0% vs. 58.1%, p = 0.012) and greater node positive disease (76.5% vs. 56.5%, p = 0.024). Overall survival was worse in patients with high plasma RNLS levels with median follow-up of 27.70 months vs. 65.03 months (p < 0.001). RNLS levels also predicted whether patients with locally advanced/borderline resectable (LA/BR) PDAC underwent resection (AUC 0.674; 95%CI 0.42-0.82, p = 0.04). Overall tissue RNLS was increased in both premalignant and malignant PDAC tissues compared to normal pancreas. Elevated plasma RNLS levels were associated with advanced tumor characteristics, decreased overall survival, and reduced resectability in patients with LA/BR PDAC. These studies show that RNLS levels are increased in premalignant pancreatic tissues and that its levels in plasma correspond to the clinical behavior of PDAC.

Role of stromal activin A in human pancreatic cancer and metastasis in mice

Pancreatic ductal adenocarcinoma (PDAC) has extensive stromal involvement and remains one of the cancers with the highest mortality rates. Activin A has been implicated in colon cancer and its stroma but its role in the stroma of PDAC has not been elucidated. Activin A expression in cancer and stroma was assessed in human PDAC tissue microarrays (TMA). Activin A expression in human TMA is significantly higher in cancer samples, with expression in stroma correlated with shorter survival. Cultured pancreatic stellate cells (PSC) were found to secrete high levels of activin A resulting in PDAC cell migration that is abolished by anti-activin A neutralizing antibody. KPC mice treated with anti-activin A neutralizing antibody were evaluated for tumors, lesions and metastases quantified by immunohistochemistry. KPC mice with increased tumor burden express high plasma activin A. Treating KPC mice with an activin A neutralizing antibody does not reduce primary tumor size but decreases tumor metastases. From these data we conclude that PDAC patients with high activin A expression in stroma have a worse prognosis. PSCs secrete activin A, promoting increased PDAC migration. Inhibition of activin A in mice decreased metastases. Hence, stroma-rich PDAC patients might benefit from activin A inhibition.

Ex vivo culture of intact human patient derived pancreatic tumour tissue

The poor prognosis of pancreatic ductal adenocarcinoma (PDAC) is attributed to the highly fibrotic stroma and complex multi-cellular microenvironment that is difficult to fully recapitulate in pre-clinical models. To fast-track translation of therapies and to inform personalised medicine, we aimed to develop a whole-tissue ex vivo explant model that maintains viability, 3D multicellular architecture, and microenvironmental cues of human pancreatic tumours. Patient-derived surgically-resected PDAC tissue was cut into 1–2 mm explants and cultured on gelatin sponges for 12 days. Immunohistochemistry revealed that human PDAC explants were viable for 12 days and maintained their original tumour, stromal and extracellular matrix architecture. As proof-of-principle, human PDAC explants were treated with Abraxane and we observed different levels of response between patients. PDAC explants were also transfected with polymeric nanoparticles + Cy5-siRNA and we observed abundant cytoplasmic distribution of Cy5-siRNA throughout the PDAC explants. Overall, our novel model retains the 3D architecture of human PDAC and has advantages over standard organoids: presence of functional multi-cellular stroma and fibrosis, and no tissue manipulation, digestion, or artificial propagation of organoids. This provides unprecedented opportunity to study PDAC biology including tumour-stromal interactions and rapidly assess therapeutic response to drive personalised treatment.