Lesinski, Gregory B

225 Background: ICIs induce durable responses in dMMR CRC patients. However, clinical and molecular biomarkers of response to ICIs have not been well-established. In this study, we investigated impact of specific MMR gene loss, BRAF V600E mutation and clinical characteristics of pts on clinical outcomes of ICIs. Methods: Pts were eligible if they had confirmed dMMR CRC by IHC or MSI-H by PCR and received ICIs between 01/01/2012 and 05/01/2019 at Winship Cancer Institute of Emory University, Mayo Clinic, Vanderbilt or Stanford University. Due to the functional dependency, the groups were categorized as protein loss of MLH1+PMS2 vs MSH2+MSH6. Log-rank test, Cox hazard model and Fisher’s exact test were used for survival outcomes, the best response and the distribution of variables among the subgroups. Results: A total of 66 pts with dMMR CRC were identified and BRAF status was available for 41 pts. ORRs in MLH1+PMS2 and MSH2+MSH6 groups were 72.9% and 56.5% respectively (P = 0.189). At 2 years, PFS rates were 55.6% and 78.2% for MLH1+PMS2 and MSH2+MSH6 groups respectively (P < 0.001). Pts with BRAF V600E mutations had significantly worse outcomes as compared to pts with wild-type BRAF (2-year PFS rate of 35.0% and 73.3% respectively; P < 0.001). Notably pts < 65 had better 2-year disease control rates when compared to > 65 (71.1% and 41.5% respectively; P < 0.001). We also observed worse 2-year PFS rates in pts with liver metastases (P = 0.014). CRC side and tumor volume did not impact 2-year PFS rates in our cohort. Conclusions: Our data suggest that pts with loss of function in MSH2+MSH6 may have better 2 year-PFS rates compared pts with MLH1+PMS2 even though ORR favored MLH1+PMS2 group suggesting that ORR may not reflect the durability of ICI response in dMMR CRC patients. Consistently, pts with BRAF V600E mutation which is associated with MLH1 promoter methylation had significantly worse 2-year PFS rates. Overall, our findings suggest that BRAFV600E mutation, the affected MMR proteins, pt age, and site of metastasis may impact durability of ICI response in dMMR CRC patients.

Abstract High-quality and well-annotated biorepositories are needed to better understand the pathophysiology and biologic mechanisms of chronic pancreatitis (CP) and its consequences. We report a methodology for the development of a robust standard operating procedure (SOP) for a biorepository based on the experience of the clinical centers within the consortium to study Chronic Pancreatitis, Diabetes and Pancreas Cancer Clinical Centers (CPDPC), supported by the National Cancer Institute and the National Institute for Diabetes and Digestive and Kidney Diseases as a unique multidisciplinary model to study CP, diabetes, and pancreatic cancer in both children and adults. Standard operating procedures from the CPDPC centers were evaluated and consolidated. The literature was reviewed for standard biorepository operating procedures that facilitated downstream molecular analysis. The existing literature on biobanking practices was harmonized with the SOPs from the clinical centers to produce a biorepository for pancreatic research. This article reports the methods and basic principles behind the creation of SOPs to develop a biorepository for the CPDPC. These will serve as a guide for investigators developing biorepositories in pancreas research. Rigorous and meticulous adherence to standardized biospecimen collection will facilitate investigations to better understand the pathophysiology and biologic mechanisms of CP, diabetes, and pancreatic cancer.

Abstract Lipocalin-2 (LCN2) promotes malignant development in many cancer types. LCN2 is upregulated in patients with pancreatic ductal adenocarcinoma (PDAC) and in obese individuals, but whether it contributes to PDAC development is unclear. In this study, we investigated the effects of Lcn2 depletion on diet-induced obesity, inflammation, and PDAC development. Mice with acinar cell–specific expression of KrasG12D were crossed with Lcn2-depleted animals and fed isocaloric diets with varying amounts of fat content. Pancreas were collected and analyzed for inflammation, pancreatic intraepithelial neoplasia (PanIN), and PDAC. We also used a syngeneic orthotopic PDAC mouse model to study tumor growth in the presence or absence of Lcn2 expression. In addition, to understand the mechanistic role of how LCN2 could be mediating PDAC, we studied LCN2 and its specific receptor solute carrier family 22 member 17 (SLC22A17) in human pancreatic cancer stellate cells (PSC), key mediators of the PDAC stroma. Depletion of Lcn2 diminished extracellular matrix deposition, immune cell infiltration, PanIN formation, and tumor growth. Notably, it also increased survival in both obesity-driven and syngeneic orthotopic PDAC mouse models. LCN2 modulated the secretion of proinflammatory cytokines in PSC of the PDAC tumor microenvironment, whereas downregulation of LCN2-specific receptor SLC22A17 blocked these effects. Our results reveal how LCN2 acts in the tumor microenvironment links obesity, inflammation, and PDAC development. Cancer Res; 77(10); 2647–60. ©2017 AACR

Objective Limited efficacy of immune checkpoint inhibitors in pancreatic ductal adenocarcinoma (PDAC) has prompted investigation into combination therapy. We hypothesised that interleukin 6 (IL-6) blockade would modulate immunological features of PDAC and enhance the efficacy of anti-programmed death-1-ligand 1 (PD-L1) checkpoint inhibitor therapy. Design Transcription profiles and IL-6 secretion from primary patient-derived pancreatic stellate cells (PSCs) were analyzed via Nanostring and immunohistochemistry, respectively. In vivo efficacy and mechanistic studies were conducted with antibodies (Abs) targeting IL-6, PD-L1, CD4 or CD8 in subcutaneous or orthotopic models using Panc02, MT5 or KPC-luc cell lines; and the aggressive, genetically engineered PDAC model (Kras LSL−G12D , Trp53 LSL−R270H , Pdx1-cre, Brca2 F/F (KPC-Brca2 mice)). Systemic and local changes in immunophenotype were measured by flow cytometry or immunohistochemical analysis. Results PSCs (n=12) demonstrated prominent IL-6 expression, which was localised to stroma of tumours. Combined IL-6 and PD-L1 blockade elicited efficacy in mice bearing subcutaneous MT5 (p<0.02) and Panc02 tumours (p=0.046), which was accompanied by increased intratumoural effector T lymphocytes (CD62L − CD44 − ). CD8-depleting but not CD4-depleting Abs abrogated the efficacy of combined IL-6 and PD-L1 blockade in mice bearing Panc02 tumours (p=0.0016). This treatment combination also elicited significant antitumour activity in mice bearing orthotopic KPC-luc tumours and limited tumour progression in KPC-Brca2 mice (p<0.001). Histological analysis revealed increased T-cell infiltration and reduced α-smooth muscle actin cells in tumours from multiple models. Finally, IL-6 and PD-L1 blockade increased overall survival in KPC-Brca2 mice compared with isotype controls (p=0.0012). Conclusions These preclinical results indicate that targeted inhibition of IL-6 may enhance the efficacy of anti-PD-L1 in PDAC.