Pancreatic Adenocarcinoma Tumors Research Articles

The Pancreatic Microbiome is Associated with Carcinogenesis and Worse Prognosis in Males and Smokers.

Simple SummaryThe cancer microbiome has been suggested to be closely involved in the immune dysregulation that leads to carcinogenesis. Given that pancreatic adenocarcinoma (PAAD) is one of the most lethal cancers, it is important to identify features of the microbiome that may contribute to more deadly PAAD tumors. In this study, we analyzed PAAD patient RNA-sequencing data from The Cancer Genome Atlas (TCGA) to correlate abundance of intra-pancreatic microbes to dysregulation of immune and cancer-associated genes and pathways. We discovered that the presence of several bacteria species within PAAD tumors is linked to metastasis and immune suppression. Furthermore, we found that the increased prevalence and poorer prognosis of PAAD in males and smokers are linked to the presence of potentially cancer-promoting or immune-inhibiting microbes. Further study into the roles of these microbes in PAAD is imperative for understanding how a pro-tumor microenvironment may be treated to limit cancer progression.An intra-pancreatic microbiota was recently discovered in several prominent studies. Since pancreatic adenocarcinoma (PAAD) is one of the most lethal cancers worldwide, and the intratumor microbiome was found to be a significant contributor to carcinogenesis in other cancers, this study aims to characterize the PAAD microbiome and elucidate how it may be associated with PAAD prognosis. We further explored the association between the intra-pancreatic microbiome and smoking and gender, which are both risk factors for PAAD. RNA-sequencing data from The Cancer Genome Atlas (TCGA) were used to infer microbial abundance, which was correlated to clinical variables and to cancer and immune-associated gene expression, to determine how microbes may contribute to cancer progression. We discovered that the presence of several bacteria species within PAAD tumors is linked to metastasis and immune suppression. This is the first large-scale study to report microbiome-immune correlations in human pancreatic cancer samples. Furthermore, we found that the increased prevalence and poorer prognosis of PAAD in males and smokers are linked to the presence of potentially cancer-promoting or immune-inhibiting microbes. Further study into the roles of these microbes in PAAD is imperative for understanding how a pro-tumor microenvironment may be treated to limit cancer progression.

AMP‑activated protein kinase family member 5 is an independent prognostic indicator of pancreatic adenocarcinoma: A study based on The Cancer Genome Atlas.

Pancreatic adenocarcinoma (PAAD) is a common and highly malignant tumor. The identification of prognostic biomarkers for PAAD could provide invaluable information for clinical treatment. AMP-activated protein kinase family member 5 (ARK5) is a member of the AMPK family that mediates the migration of PAAD cells. In the present study, ARK5 expression was evaluated using bioinformatics analysis in public datasets from The Cancer Genome Atlas. The expression levels of ARK5 in PAAD tumor tissue were significantly increased, compared with matched non-cancerous tissues. ARK5 target genes were then predicted and Gene Ontology Biological Processes, Kyoto Encyclopedia of Genes and Genomes pathway analysis and Reactome gene sets were used to determine the functions associated with the target genes. A protein-protein interaction network was also constructed to find out the node genes and observe their association with the overall survival rate of PAAD. A total of nine node genes were identified in the PPI network, of which six were significantly upregulated in PAAD tissue, compared with matched normal tissue. The prognostic value of each node gene was evaluated by comparing the overall survival in patients with PAAD stratified according to the expression levels of these genes. Overall survival was significantly reduced in patients with high polo-like kinase-1 (PLK1) or protein phosphatase 1 catalytic subunit β (PPP1CB) expression, compared with patients with low expression of these genes. To further evaluate the relationship between PAAD and ARK5, ARK5 immunohistochemical staining was performed in a tissue microarray consisting of 112 tumor samples from patients with PAAD and adjacent normal tissue samples. ARK5 protein expression in PAAD tissue was markedly increased, compared with non-cancerous tissue (P=7.631×10−11). Moreover, ARK5 protein levels were associated with N stage (P=0.018). The overall survival of patients with PAAD with high ARK5 protein expression levels was reduced (P=0.014), compared with patients with low expression. In conclusion, these findings suggested that ARK5 may represent an independent prognostic indicator of PAAD.

Immediate and durable therapeutic response after EUS-guided radiofrequency ablation of a pancreatic insulinoma.

EUS-guided radiofrequency ablation (RFA) is an endoscopic procedure and emerging therapeutic option for the treatment of pancreatic tumors.1-3 It has been described in recent years for local therapy of pancreatic adenocarcinoma and neuroendocrine tumors in patients for whom operative management is deemed unsuitable.1,4,5 Hyperthermic ablation using radiofrequency waves at 500 kHz is used to induce irreversible cellular injury and necrosis of the target lesion.6,7 Precise delivery of thermal energy is critical to spare the normal surrounding pancreatic tissue from injury.

VCAN accumulation and proteolysis as predictors of T lymphocyte-excluded and permissive tumor microenvironments.

3127 Background: Immune checkpoint inhibitors (ICIs) represent a major advance for treating solid tumors. However, only a minority of patients (pts) benefit from these therapies and markers that predict response have been elusive. Versican (VCAN) is an immunosuppressive proteoglycan in the tumor microenvironment (TME), which releases an immunostimulatory N-terminal fragment versikine (Vkine) when cleaved by ADAMTS proteases. We have demonstrated in colorectal cancers (CRC) that a low VCAN/high Vkine (VCAN proteolytic predominant [VPP]) phenotype correlates with increased tumor-infiltrating CD8+ T lymphocytes (TILs). Here we examine the accumulation of VCAN as a marker of immune exclusion and its proteolysis as a marker of an immune-permissive TME. Methods: Immunohistochemistry for VCAN, Vkine and CD8+ was performed on samples from 1662 pts across breast (BC), CRC, endometrial cancer, pancreatic adenocarcinoma (PDAC), esophageal cancers and neuroendocrine tumors (NETs), across stages of disease (I-IV) and with diverse prior treatments. Stromal intensities of VCAN and Vkine staining quantified in collaboration with blinded surgical pathologists using a 0-3+ scale. 0/1+ were considered “low” for both VCAN and Vkine, whereas 2/3+ were considered “high”. The number of CD8+ TILs were counted using 400x magnification, the equivalent of a high power field (hpf). Results: Across the entire cohort VCAN phenotypes were diverse (VCAN high/Vkine low, 21%; VCAN high/Vkine high, 23%; VCAN low/Vkine low, 29%; VCAN low/Vkine high (VPP), 27%). Consistent with VCAN accumulation as a marker of T cell exclusion, VCAN low cancers had increased TILs compared to VCAN high (4.8 vs 18.3 TILs/hpf, p < 0.001). Low VCAN was identified in 85% esophageal, 79% NET (including small cell lung cancer [SCLC]) 72% endometrial, 47% MSI-H CRCs, 28% triple-negative BC and only 22% MSS CRC, 18% PDAC, 17% ER+ BCs. The VPP subgroup had the highest TILs per hpf across tumors. VPP was identified in 47% of esophageal, 45% endometrial, 41% NETs (including SCLC), 24% MSI-H CRCs, and only 9% MSS CRC, 7% ER+ BCs, 3% triple-negative BCs, and 0% of PDAC (n = 131 PDAC pts). Conclusions: VCAN accumulation correlates with T lymphocyte exclusion, while VCAN proteolysis predicts an immune permissive phenotype. VCAN accumulation and proteolysis are now incorporated into ICI clinical trials as a potential marker of response. Future studies will clarify the role of these biomarkers in predicting benefits of immuno-oncology treatment strategies.

Blood levels of steroid hormone precursors allow differentiation between pancreatic adenocarcinoma and neuroendocrine tumors.

e16692 Background: The activity of some enzymes involved in the synthesis and transformation of sex hormones changes in some tumor tissues of the pancreas, which can affect the circulating concentrations of these hormones in the blood. The purpose of the study was to determine the possibility of differential diagnosis of pancreatic cancer at primary examination. Methods: Levels of 17OHP and DHEAS were measured by RIA in the blood of 25 men with chronic pancreatitis (CP), 34 patients with pancreatic adenocarcinoma (PA) and 15 patients with pancreatic neuroendocrine tumors (PNET). The results were compared with the levels in 23 healthy donors. All patients gave voluntary informed consent for the study. Results: Men with CP did not show statistically significant changes in 17OHP and DHEAS. The levels in pancreatic cancers were lower than in donors: in PA, DHEAS was 1.6 times and 17OHP - 1.4 times lower than the norm. DHEAS in PNET was 2.4 times lower than the norm and 1.5 times lower than in PA. 17OHP in PNET was 6.4 and 4.5 times lower, respectively. Conclusions: Measuring DHEAS and 17OHP in the blood can serve as an informative laboratory test for predictor assessment of the nature of pancreatic disease.

Phase I study of mesothelin-targeted immunotoxin LMB-100 given as a long infusion with or without nab-paclitaxel.

3553 Background: LMB-100 recombinant immunotoxin consists of a mesothelin-binding Fab for targeting a modified Pseudomonas exotoxin A payload. Previous Phase 1 clinical testing of a 30-minute LMB-100 “short” infusion format identified a serum half-life of ~1 hour. Pre-clinical data suggested that extending infusion time could improve anti-tumor efficacy by increasing tumor cell duration of exposure to LMB-100. The primary objective of this study was to determine the safety and tolerability of administering LMB-100 in a long infusion format over 24-48 hours alone or with nab-paclitaxel chemotherapy in patients with mesothelin-expressing solid tumors. Methods: Patients (n = 15) with pancreatic adenocarcinoma and other mesothelin-expressing solid tumors (n = 3; mesothelioma, colon, and ampullary cancers) treated on 3 dose levels received long infusion of LMB-100 (65 or 100 mcg/kg/day) for 24 hour on Days 1 and 4 (n = 6) or 48 hour on Day 1 (n = 9) with or without a loading dose (40 mcg/kg over 30 minutes) for up to 2 cycles. In the second arm, patients (n = 5) with pancreatic adenocarcinoma were treated with LMB-100 over 24 hours on Day 1 concurrently with nab-paclitaxel (125 mg/m2) for up to 3 cycles. Results: DLT of proteinuria (grade 3) in one patient and acute kidney injury (grade 1) in one patient were observed amongst patients receiving 100 mcg/kg/day over 48 hours and 24 hours, respectively. No objective responses were seen but all patients receiving nab-paclitaxel had > 50% decrease in CA 19-9. Patients at all single agent dose levels (8 of 10 evaluable) developed high titer anti-drug antibodies (ADAs) against LMB-100. Those with ADAs (8 of 8) had undetectable cycle 2 peak plasma LMB-100 concentration. Development of high titer ADAs occurred more frequently with long infusion than seen previously with “short” infusion LMB-100. Most long infusion patients (19 of 20) developed increased serum IL-6 within 24 hours of LMB-100 infusion. However, the systemic inflammatory response to LMB-100 (as measured by increased serum CRP) which occurs in most “short” infusion patients was not observed. Conclusions: Long infusion format LMB-100 is generally well tolerated but immunogenicity limits treatment to 1 effective cycle. No anti-tumor efficacy of the single agent was observed. Clinical trial information: NCT02810418 .

Reverse engineering a predictive signature characterized by proliferation, DNA damage, and immune escape from stage I lung adenocarcinoma recurrence.

Identifying early-stage cancer patients at risk for progression is a major goal of biomarker research. This report describes a novel 19-gene signature (19-GCS) that predicts stage I lung adenocarcinoma (LAC) recurrence and response to therapy and performs comparably in pancreatic adenocarcinoma (PAC), which shares LAC molecular traits. Kaplan-Meier, Cox regression, and cross-validation analyses were used to build the signature from training, test, and validation sets comprising 831 stage I LAC transcriptomes from multiple independent data sets. A statistical analysis was performed using the R language. Pathway and gene set enrichment were used to identify underlying mechanisms. 19-GCS strongly predicts overall survival and recurrence-free survival in stage I LAC (P=0.002 and P<0.001, respectively) and in stage I-II PAC (P<0.0001 and P<0.0005, respectively). A multivariate cox regression analysis demonstrated the independence of 19-GCS from significant clinical factors. Pathway analyses revealed that 19-GCS high-risk LAC and PAC tumors are characterized by increased proliferation, enhanced stemness, DNA repair deficiency, and compromised MHC class I and II antigen presentation along with decreased immune infiltration. Importantly, high-risk LAC patients do not appear to benefit from adjuvant cisplatin while PAC patients derive additional benefit from FOLFIRINOX compared with gemcitabine-based regimens. When validated prospectively, this proof-of-concept biomarker may contribute to tailoring treatment, recurrence reduction, and survival improvements in early-stage lung and pancreatic cancers.

Treatment of CEA-positive solid tumors with anti-CEA chimeric antigen receptor T-cells in CEA transgenic mice

Abstract Chimeric antigen receptors (CARs) combine specificity of antibody to target antigen on cancer cells with the potent cytotoxic activity of T-cells without the need for MHC recognition. Chimeric antigen receptor (CAR) T-cells that were designed to express the single chain variable fragment binding domain of human anti-CEA antibody BW431/26 on mouse splenocytes were able to reduce CEA-expressing pancreatic adenocarcinoma tumor in CEA-transgenic (CEAtg) mice without significant off-target effects (Chmielewski et al., 2012). In this study, an anti-CEA CAR construct derived from murine anti-CEA antibody (T84.66) expressed on human T-cells targeted CEA+ colon carcinoma cells (LS174T/CEA and MC38CEA) with high specificity in vitro. When co-incubated with CEA-positive or CEA-negative mouse cancer cells, anti-CEA CAR expressed on mouse T-cells specifically targeted CEA-positive cancer cells in vitro. Compared to mock T-cells control, anti-CEA CAR T-cells injected intravenously delayed subcutaneous MC38CEA tumor growth in CEAtg mice. Lymphodepletion via cyclophosphamide injected before anti-CEA T-cells therapy further delayed subcutaneous MC38CEA tumor growth in CEAtg mice. To improve the therapeutic potential of anti-CEA CAR T-cells, IL2 was conjugated to a humanized anti-CEA antibody to form an immunocytokine (ICK). The ICK was injected interperitoneally after anti-CEA CAR T-cells into lymphodepleted CEAtg mice. A single injection of the ICK delayed subcutaneous MC38CEA tumor growth even further. Four injections of ICK after anti-CEA CAR T-cells eradicated subcutaneous MC38CEA tumors. These data show the therapeutic potential of anti-CEA CAR T-cells to target CEA-positive tumors.

GPCRs in pancreatic adenocarcinoma: Contributors to tumour biology and novel therapeutic targets.

Pancreatic cancer has one of the highest mortality rates (5-year survival ~9%) among cancers. Pancreatic adenocarcinoma (PAAD) is the most common (>80%) and the most lethal type of pancreatic cancer. A need exists for new approaches to treat pancreatic adenocarcinoma. GPCRs, the largest family of cell-surface receptors and drug targets, account for ~35% of approved drugs. Recent studies have revealed roles for GPCRs in PAAD cells and cells in the tumour micro-environment. This review assesses current information regarding GPCRs in PAAD by summarizing omics data for GPCRs expression in PAAD. The PAAD "GPCRome" includes GPCRs with approved agents, thereby offering potential for their repurposing/repositioning. We then reviewed the evidence for functional roles of specific GPCRs in PAAD. We also highlight gaps in understanding the contribution of GPCRs to PAAD biology and identify several GPCRs that may be novel therapeutic targets for future work in search of GPCR-targeted drugs to treat PAAD tumours.

Evaluation of ICD codes and phecodes for the identification of pancreatic cancer in a large genomic database.

642 Background: Large genomic databases linked to electronic health records promise to shed light on molecular mechanisms underlying rare diseases, such as pancreatic cancer. However, accurately identifying patients with the desired phenotype can be challenging. This is particularly the case for pancreatic tumors, since ICD codes do not distinguish between pancreatic adenocarcinoma (PDAC) and pancreatic neuroendocrine tumors (pNET). Previous studies have shown that ICD codes aggregated by phenotype, known as “phecodes”, have a higher accuracy in identifying specific phenotypes than ICD codes themselves; however, their performance in identifying cancers of the pancreas has not been studied. Methods: From a large deidentified genomic database, two queries were performed to identify all adults with pancreatic cancer for a GWAS study, one using ICD-9/10 codes and the other using phecodes. The medical records for all patients identified from both queries were then reviewed to confirm the presence and histologic type of pancreatic cancer. Results: Of the 91,985 genotyped adults in the database, ICD-9/10 codes identified 1,247 patients with pancreatic cancer, compared with only 422 patients identified by the phecode query. All patients in the phecode cohort were also found in the ICD cohort. Of the 1,247 patients in the ICD cohort, 760 were confirmed to have pancreatic cancer on review of the health records (594 with PDAC, 166 with pNET) whereas in the phecode cohort, only 251 were confirmed to have pancreatic cancer (159 with PDAC, 92 pNET). The positive predictive value (PPV) for PDAC in the ICD query was 47%, compared with 38% for the phecode cohort. The ICD and phecode cohorts had similarly low numbers of pre-malignant cystic tumors (5% in each cohort) and other periampullary cancers (3%). Conclusions: In this large genomic database, the use of ICD-9/10 codes for pancreatic cancer was able to identify nearly three times as many patients with pancreatic cancer and had a higher PPV compared to using phecodes. Therefore, ICD codes, rather than phecodes, should be used to identify patients with pancreatic cancer for subsequent genotyping analysis, though caution is required because the PPV is still low.

Clinical significance of MUC4 isoforms in pancreatic cancer patients.

742 Background: Pancreatic adenocarcinoma (PC) is a highly aggressive cancer with a 5-year survival rate around 9% with majority of patients diagnosed at advanced stage. Prior studies describe transcriptomic alterations during tumorigenesis, of which novel and progressive expression of mucins are significant. Mucins are large secreted or membrane-tethered glycoproteins that have been shown to be of pathogenic importance in PC. Methods: We explored differential expression and survival outcomes based on mucin expression using TCGA PC patients (n = 150). RNA-Seq. reads were realigned to all known mucin splice variant (SV) sequences. Hazard ratios (HR) were calculated for all SVs (n = 123), and SVs with significant HRs were plotted on Kaplan-Maier survival curves comparing expression about the median. The MUC4 SV (MUC4Δ6) was selected for validation in patient tumor samples (n = 17) due to PC tumor cell-specific expression and in-frame deletion of a single exon. After discovery of significant mucin SVs, we designed a gold-nanoparticle (GNP) assay to specifically detect MUC4Δ6 in circulation from PC patient plasma. Results: In the absence of significant mucin-based survival differences, we expanded our analysis to include mucin SV transcripts. Through hazard and survival analyses, we identified 3 MUC1 SVs with better survival (SV1 HR = .61, p = .033; SV2 HR = .64, p = .05; SV3 HR = .62, p = .04), and one each of MUC4 (HR = 1.93, p = .028) and MUC16 (HR = 1.90, p = .027) with worse prognosis. In a validation cohort, we found 10 samples had a high cellularity (HC) gene signature. Expression of MUC4Δ6 was 4804.7 copies/100,000 GPI copies in the HC population and expressors above the median had a median survival of 397 days compared to1964.5 days (p = .191) in low expressors. Our novel GNP assay detected MUC4∆6 transcripts at minimum concentrations of 100 fM with a synthetic RNA. Uniquely, our assay detects the MUC4∆6 SV but not wild-type variant. Conclusions: We were able to determine that expression of specific mucin SV are prognostic in PC patients. We developed technology to detect MUC4Δ6 transcript in circulation using a novel GNP assay. Future studies will seek to stabilize the nanoparticles and modify them for potential diagnostic purposes in a clinical setting.

Abstract A081: Phase I study of mesothelin-targeted immunotoxin LMB-100 given as a long infusion

Abstract Purpose: LMB-100 recombinant immunotoxin consists of a mesothelin-binding Fab for targeting and a modified Pseudomonas exotoxin A payload. Previous Phase 1 clinical testing of a 30-minute LMB-100 infusion format identified dose-limiting toxicity (DLT) of capillary leak syndrome (CLS) and a serum half-life of ~60 minutes. Pre-clinical data suggested that extending infusion time could improve anti-tumor efficacy by increasing tumor cell duration of exposure to LMB-100. The primary objective of this study was to determine the safety and tolerability of administering LMB-100 over a longer infusion time. We hypothesized that reduced CMAX would result in decreased severity of off-target toxicities like CLS without decreasing anti-tumor activity. Patients and Methods: Patients (n = 15) with pancreatic adenocarcinoma and other mesothelin-expressing solid tumors (n = 3; mesothelioma, colon adenocarcinoma, ampullary carcinoma) treated on 3 dose levels received long infusion (24-48 hours) LMB-100 (65 or 100 mcg/kg/day) with or without a loading dose (40 mcg/kg over 30 minutes) for up to 2 cycles. Safety and tolerability, pharmacokinetics, immunogenicity and anti-tumor activity were assessed. Results: DLT of proteinuria (grade 3) was observed in 1 of 6 patients receiving 100 mcg/kg/day over 48 hours with pre-load. Three of 6 patients at this dose level developed significant CLS (&amp;gt;5 kg weight gain from fluid edema) that was not dose-limiting. No CLS was observed in the 6 patients who received 100 mcg/kg over 24 hours on days 1 and 4 with pre-load. Increased immunogenicity was observed with the long infusion compared to standard administration format: 8 of 9 patients receiving 2nd cycle treatment had undetectable plasma LMB-100 concentration during this cycle that was associated with the development of high titer anti-LMB-100 antibodies. Progressive disease was observed in 11 of 12 evaluable patients, and none of 8 evaluable patients with pancreatic adenocarcinoma had a clinically significant decline in CA 19-9 tumor marker. Conclusions: Long infusion format of delivery for LMB-100 can reduce CLS but increases immunogenicity. No anti-tumor activity was observed. Citation Format: Christine Alewine, Mehwish Iqra Ahmad, Cody J Peer, Seth Steinberg, William D Figg, Raffit Hassan, Ira Pastan. Phase I study of mesothelin-targeted immunotoxin LMB-100 given as a long infusion [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A081. doi:10.1158/1535-7163.TARG-19-A081

Does the Artery-first Approach Improve the Rate of R0 Resection in Pancreatoduodenectomy?: A Multicenter, Randomized, Controlled Trial.

To compare the rates of R0 resection in pancreatoduodenectomy (PD) for pancreatic and periampullary malignant tumors by means of standard (ST-PD) versus artery-first approach (AFA-PD). Standardized histological examination of PD specimens has shown that most pancreatic resections thought to be R0 resections are R1. "Artery-first approach" is a surgical technique characterized by meticulous dissection of arterial planes and clearing of retropancreatic tissue in an attempt to achieve a higher rate of R0. To date, studies comparing AFA-PD versus ST-PD are retrospective cohort or case-control studies. A multicenter, randomized, controlled trial was conducted in 10 University Hospitals (NCT02803814, ClinicalTrials.gov). Eligible patients were those who presented with pancreatic head adenocarcinoma and periampullary tumors (ampulloma, distal cholangiocarcinoma, duodenal adenocarcinoma). Assignment to each group (ST-PD or AFA-PD) was randomized by blocks and stratified by centers. The primary end-point was the rate of tumor-free resection margins (R0); secondary end-points were postoperative complications and mortality. One hundred seventy-nine patients were assessed for eligibility and 176 randomized. After exclusions, the final analysis included 75 ST-PD and 78 AFA-PD. R0 resection rates were 77.3% (95% CI: 68.4-87.4) with ST-PD and 67.9% (95% CI: 58.3-79.1) with AFA-PD, P=0.194. There were no significant differences in postoperative complication rates, overall 73.3% versus 67.9%, and perioperative mortality 4% versus 6.4%. Despite theoretical oncological advantages associated with AFA-PD and evidence coming from low-level studies, this multicenter, randomized, controlled trial has found no difference neither in R0 resection rates nor in postoperative complications in patients undergoing ST-PD versus AFA-PD for pancreatic head adenocarcinoma and other periampullary tumors.

Somatostatin and chemokine CXCR4 receptor expression in pancreatic adenocarcinoma relative to pancreatic neuroendocrine tumours.

Pancreatic adenocarcinoma (PAC) represents one of the most fatal types of cancer with an exceptionally poor prognosis, underscoring the need for improved diagnostic and treatment approaches. An over-expression of somatostatin receptors (SST) as well as of the chemokine receptor CXCR4 has been shown for many tumour entities. Respective expression data for PAC, however, are scarce and contradictory. Overall, 137 tumour samples from 70 patients, 26 of whom were diagnosed with PAC and 44 with pancreatic neuroendocrine tumour (PanNET), were compared in terms of SST and CXCR4 expression by immunohistochemical analysis using well-characterized rabbit monoclonal antibodies. Only SST1 and CXCR4 expression was detected in PAC tumours, with SST1 present in 42.3% and CXCR4 in 7.7% of cases. However, the overall staining intensity was very weak. In contrast to the tumour cells, in many PAC cases, tumour capillaries exhibited strong SST3, SST5, or CXCR4 expression. In PanNETs, SST2 was the most-prominently expressed receptor, observed in 75.0% of the tumours at medium-strong intensity. SST5, SST1, and CXCR4 expression was detected in 20.5%, 15.9%, and 11.4% of PanNET cases, respectively, but the staining intensity was only weak. SST2 positivity in PanNET, but not in PAC, was associated with favourable patient outcomes. SST or CXCR4 expression in PAC is clearly of no therapeutic relevance. However, indirect targeting of these tumours via SST3, SST5, or CXCR4 on tumour microvessels may represent a promising additional therapeutic strategy.

CXCR4-Directed Imaging in Solid Tumors.

Despite histological evidence in various solid tumor entities, available experience with CXCR4-directed diagnostics and endoradiotherapy mainly focuses on hematologic diseases. With the goal of expanding the application of CXCR4 theranostics to solid tumors, we aimed to elucidate the feasibility of CXCR4-targeted imaging in a variety of such neoplasms.Methods: Nineteen patients with newly diagnosed, treatment-naïve solid tumors including pancreatic adenocarcinoma or neuroendocrine tumor, cholangiocarcinoma, hepatocellular carcinoma, renal cell carcinoma, ovarian cancer, and prostate cancer underwent [68Ga]Pentixafor PET/CT. CXCR4-mediated uptake was assessed both visually and semi-quantitatively by evaluation of maximum standardized uptake values (SUVmax) of both primary tumors and metastases. With physiologic liver uptake as reference, tumor-to-background ratios (TBR) were calculated. [68Ga]Pentixafor findings were further compared to immunohistochemistry and [18F]FDG PET/CT.Results: On [68Ga]Pentixafor PET/CT, 10/19 (52.6%) primary tumors were visually detectable with a median SUVmax of 5.4 (range, 1.7–16.0) and a median TBR of 2.6 (range, 0.8–7.4), respectively. The highest level of radiotracer uptake was identified in a patient with cholangiocarcinoma (SUVmax, 16.0; TBR, 7.4). The relatively low uptake on [68Ga]Pentixafor was also noted in metastases, exhibiting a median SUVmax of 4.5 (range, 2.3–8.8; TBR, 1.7; range, 1.0–4.1). A good correlation between uptake on [68Ga]Pentixafor and histological derived CXCR4 expression was noted (R = 0.62, P < 0.05). In the 3 patients in whom [18F]FDG PET/CT was available, [68Ga]Pentixafor exhibited lower uptake in all lesions.Conclusions: In this cohort of newly diagnosed, treatment-naïve patients with solid malignancies, CXCR4 expression as detected by [68Ga]Pentixafor-PET/CT and immunohistochemistry was rather moderate. Thus, CXCR4-directed imaging may not play a major role in the management of solid tumors in the majority of patients.

Mesothelin-Targeted Immunotoxin LMB-100 in Combination With Tofacitinib in Persons With Previously Treated Pancreatic Adenocarcinoma, Cholangiocarcinoma and Other Mesothelin Expressing Solid Tumors

Mesothelin-Targeted Immunotoxin LMB-100 in Combination With Tofacitinib in Persons With Previously Treated Pancreatic Adenocarcinoma, Cholangiocarcinoma and Other Mesothelin Expressing Solid Tumors

Follow "the superior mesenteric artery": laparoscopic approach for total mesopancreas excision during pancreaticoduodenectomy.

The prognosis of patients affected by pancreatic adenocarcinoma and periampullary tumors is dismal, mainly due to aggressive tumor biology and low rate of resectability at the diagnosis. Among resectable patients, the quality of surgical resection, with a particular focus on the complete resection of the retropancreatic tissue (the so-called "mesopancreas") encircling the superior mesenteric artery (SMA), has a cardinal role. With this assumption, many pancreatic surgeons recommend periadventitial dissection of the SMA in order to obtain a total mesopancreas excision (TMpE), maximizing surgical margin and minimizing R1 resection rate. To introduce our approaches for periadventitial dissection of the SMA, tailored to patient and tumor characteristics and aiming at obtaining a TMpE, during laparoscopic pancreatoduodenectomy (LPD). Three different approaches for the SMA periadventitial dissection during LPD are described: the right, the right-left, and the anterior SMA-first approach. Indications, advantages, and technical aspects of each technique are reported, as well as pathologic results, particularly focusing on resection margin status and removed lymphnodes number, safety, and feasibility. Overall, R0 rate and number of lymphnodes retrieved were 86% and 26, respectively, without significant differences according to the SMA approach performed. Rate of conversion to laparotomy due to intraoperative bleeding during SMA dissection step was 6% (3/48) among patients who underwent the right SMA approach and nil among remaining patients. During LPD, a tailored approach for periadventitial dissection of SMA makes TMpE feasible, safe, and oncologic valid, when performed by a team experienced with mininvasive approach and pancreatic surgery.

The systemic activin response to pancreatic cancer: implications for effective cancer cachexia therapy.

BackgroundPancreatic ductal adenocarcinoma (PDAC) is a particularly lethal malignancy partly due to frequent, severe cachexia. Serum activin correlates with cachexia and mortality, while exogenous activin causes cachexia in mice.MethodsIsoform‐specific activin expression and activities were queried in human and murine tumours and PDAC models. Activin inhibition was by administration of soluble activin type IIB receptor (ACVR2B/Fc) and by use of skeletal muscle specific dominant negative ACVR2B expressing transgenic mice. Feed‐forward activin expression and muscle wasting activity were tested in vivo and in vitro on myotubes.ResultsMurine PDAC tumour‐derived cell lines expressed activin‐βA but not activin‐βB. Cachexia severity increased with activin expression. Orthotopic PDAC tumours expressed activins, induced activin expression by distant organs, and produced elevated serum activins. Soluble factors from PDAC elicited activin because conditioned medium from PDAC cells induced activin expression, activation of p38 MAP kinase, and atrophy of myotubes. The activin trap ACVR2B/Fc reduced tumour growth, prevented weight loss and muscle wasting, and prolonged survival in mice with orthotopic tumours made from activin‐low cell lines. ACVR2B/Fc also reduced cachexia in mice with activin‐high tumours. Activin inhibition did not affect activin expression in organs. Hypermuscular mice expressing dominant negative ACVR2B in muscle were protected for weight loss but not mortality when implanted with orthotopic tumours. Human tumours displayed staining for activin, and expression of the gene encoding activin‐βA (INHBA) correlated with mortality in patients with PDAC, while INHBB and other related factors did not.ConclusionsPancreatic adenocarcinoma tumours are a source of activin and elicit a systemic activin response in hosts. Human tumours express activins and related factors, while mortality correlates with tumour activin A expression. PDAC tumours also choreograph a systemic activin response that induces organ‐specific and gene‐specific expression of activin isoforms and muscle wasting. Systemic blockade of activin signalling could preserve muscle and prolong survival, while skeletal muscle‐specific activin blockade was only protective for weight loss. Our findings suggest the potential and need for gene‐specific and organ‐specific interventions. Finally, development of more effective cancer cachexia therapy might require identifying agents that effectively and/or selectively inhibit autocrine vs. paracrine activin signalling.

Abstract 1832: Ligand-dependent Wnt signaling directs metabolic adaptations to promote pancreatic tumorigenesis

Abstract Wnt/β-catenin signaling plays important roles in pancreatic adenocarcinoma (PDA) tumor initiation and progression via broad-ranging effects on proliferation, differentiation, survival, and stemness. Although Wnt has been shown to promote glycolysis in colon cancer, its role in regulating metabolism in PDA has not been explored in any detail. For this study, the AsPC-1 cell line was selected as an exemplar of ligand-dependent autocrine Wnt signaling in PDA. AsPC-1 harbors an inactivating mutation in RNF43 that confers Wnt growth-dependency and response to LGK974, a PORCN inhibitor that blocks Wnt ligand secretion and signaling. Global transcriptomic, proteomic, and metabolomic analysis revealed several metabolites and putative mediators of metabolism that are directly or indirectly linked to autocrine Wnt signaling in AsPC-1. In contrast to colon cancer, pharmacologic inhibition of Wnt by LGK974 in AsPC-1 led to the accumulation of pyruvate and lactate, as well as reduced tricarboxylic acid cycle metabolites and decreased mitochondrial membrane potential as measured by tetramethylrhodamine assay. These metabolic changes were accompanied by cell cycle arrest and downregulation of transcriptional programs involved in cell cycle progression, DNA replication, and nucleotide metabolism. Pyruvate analogs dichloroacetate and oxamate, that respectively target pyruvate dehydrogenase kinase and lactate dehydrogenase, restored mitochondrial membrane potential in the context of LGK974. Importantly, LGK974 results were phenocopied by siRNA-mediated knockdown of WNT7B. Thus, inhibition of mitochondrial oxidative phosphorylation by LGK974 in RNF43-mutant PDA appears mechanistically linked to its inhibition of canonical Wnt signaling, an adaptation and potential metabolic vulnerability that could be leveraged to therapeutic advantage via combinatorial strategies. Altogether, these results suggest tissue context and differing mechanisms of Wnt pathway activation or signal strength may profoundly influence its role in regulating cancer metabolism. Citation Format: Kristina Y. Aguilera, Rana Riahi, Edris A. Saadat, Anna R. Lay, Thuc Le, Anthony Cabebe, Timothy R. Donahue, Caius Radu, David W. Dawson. Ligand-dependent Wnt signaling directs metabolic adaptations to promote pancreatic tumorigenesis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1832.

Abstract 1551: First in class immunotherapy targeting Galectin-9 promotes T-cell activation and anti-tumor response against pancreatic cancer and other solid tumors

Abstract Background: Pancreatic adenocarcinoma (PDA) is one of the deadliest forms of cancer, with a five-year survival rate at or below seven percent. Current immunotherapies show promise in treating other cancers, but success remains elusive for pancreatic cancer. Poor prognosis in pancreatic cancer is invariably linked to immune dysfunction. We have shown that in PDA, Galectin-9 (Gal-9) plays a significant role in facilitating a tumor-permissive immune microenvironment. Specifically, Gal-9 modulates immunosuppression via binding to multiple partner molecules (TIM-3, Dectin-1, CD44, CD206 etc). In light of these findings, we have developed and characterized first-in-class, therapeutic monoclonal antibodies to target Gal-9 and impede tumor growth. Methods: A proprietary synthetic, human antibody library was screened via phage display to identify high-affinity antibodies cross-reactive with human, cynomolgus and rodent Gal-9, to enable efficacy and toxicity studies. We used surface plasmon resonance and bead-based assays to measure antibody binding affinity. ELISA and cell-based approaches were used to demonstrate antibody blockade of Gal-9 binding to known ligands, inferring potential therapeutic efficacy. Efficacy in multiple IgG formats were assayed using KPC (Pdx1Cre; KrasG12D; Tp53R172H)-derived cancer cells implanted orthotopically into the pancreas of C57BL/6 mice. Patient-derived organotypic tumor spheroids (PDOTs) derived from PDA and other GI tumors, which recapitulate complex tumor architecture, were treated with anti-Gal-9 antibodies and resulting immune profile was analyzed via flow cytometry. Results: Our lead clinical candidate Gal-9 antibodies exhibit specific binding towards mouse, cynomolgus and human Gal-9 with KDvalues in the sub nanomolar range. These antibodies potently block Gal-9 interactions with known ligands such as CD206 and Dectin-1. These antibodies also inhibit Gal-9 mediated apoptosis of Jurkat cells. Mice bearing orthotopic pancreatic tumors treated with Gal-9 antibodies induced significant reduction in tumor size (p&amp;lt;0.005) compared with relevant controls. Immune profiling showed increased T cell activation and modulation of the monocytic compartment towards an immune permissive state. PDOTs showed similar immune profiles including an increase in type 1 inflammatory cytokines and effector T cell activation. Conclusions: Our Gal-9 lead therapeutic antibody has been identified, characterized and is being further assessed in expanding pre-clinical efficacy, molecular and safety studies in preparation for an IND filing. Our data demonstrate novel cancer immune biology with therapeutic implications of a first-in-class monoclonal antibody against Gal-9 to reverse immunosuppressive mechanisms contributing to tumor growth immune escape in pancreatic cancer and other solid tumors. Citation Format: Linxiao Chen, Wei Wang, Akiko Koide, Joseph Bolen, George Miller, Shohei Koide. First in class immunotherapy targeting Galectin-9 promotes T-cell activation and anti-tumor response against pancreatic cancer and other solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1551.