Purpose: Pancreatic ductal adenocarcinoma (PDAC) has the lowest five-year survival rate of all cancers in the United States. Programmed death 1 receptor (PD-1)-programmed death ligand 1 (PD-L1) immune checkpoint inhibition has been unsuccessful in clinical trials. Myeloid-derived suppressor cells (MDSCs) are known to block anti-tumor CD8+ T cell immune responses in various cancers including pancreas. This has led us to our objective that was to develop a clinically relevant in vitro organoid model to specifically target mechanisms that deplete MDSCs as a therapeutic strategy for PDAC. Method: Murine and human pancreatic ductal adenocarcinoma (PDAC) autologous organoid/immune cell co-cultures were used to test whether PDAC can be effectively treated with combinatorial therapy involving PD-1 inhibition and MDSC depletion. Results: Murine in vivo orthotopic and in vitro organoid/immune cell co-culture models demonstrated that polymorphonuclear (PMN)-MDSCs promoted tumor growth and suppressed cytotoxic T lymphocyte (CTL) proliferation, leading to diminished efficacy of checkpoint inhibition. Mouse- and human-derived organoid/immune cell co-cultures revealed that PD-L1-expressing organoids were unresponsive to nivolumab in vitro in the presence of PMN-MDSCs. Depletion of arginase 1-expressing PMN-MDSCs within these co-cultures rendered the organoids susceptible to anti-PD-1/PD-L1-induced cancer cell death. Conclusions: Here we use mouse- and human-derived autologous pancreatic cancer organoid/immune cell co-cultures to demonstrate that elevated infiltration of polymorphonuclear (PMN)-MDSCs within the PDAC tumor microenvironment inhibit T cell effector function, regardless of PD-1/PD-L1 inhibition. We present a pre-clinical model that may predict the efficacy of targeted therapies to improve the outcome of patients with this aggressive and otherwise unpredictable malignancy.

The identification and characterization of esophageal stem cells are critical to our understanding of the biology of the esophageal epithelium in health and disease. However, the proliferative compartment within the mouse esophageal epithelium remains poorly characterized. Here, we report that the basal cells of the mouse esophagus can be separated into three phenotypically and functionally distinct subpopulations based on the expression of α6 integrin and transferrin receptor (CD71). Cells that express high levels of α6 integrin and low levels of CD71, termed α6briCD71dim, are a minor subpopulation of small and undifferentiated cells that are enriched for label-retaining cells and thus represent a putative esophageal stem cell population. Conversely, cells expressing high levels of both α6 integrin and CD71 (α6briCD71bri), the majority of basal esophageal cells, are enriched for actively cycling cells and therefore represent a transit-amplifying population. Kinetic analyses revealed that a third cell population, which is α6 integrin-dim and CD71-bright (α6dim), is destined to leave the basal layer and differentiate.

Background: Increased accessibility to the internet and mobile devices has seen a rapid expansion in electronic health (eHealth) behavior change interventions delivered to patients with cancer and survivors using synchronous, asynchronous, and combined delivery methods. Characterizing effective delivery methods of eHealth interventions is required to enable improved design and implementation of evidence-based health behavior change interventions. Objective: This study aims to systematically review the literature and synthesize evidence on the success of eHealth behavior change interventions in patients with cancer and survivors delivered by synchronous, asynchronous, or combined methods compared with a control group. Engagement with the intervention, behavior change, and health outcomes, including quality of life, fatigue, depression, and anxiety, were examined. Methods: A search of Scopus, Ovid MEDLINE, Excerpta Medica dataBASE, Cumulative Index to Nursing and Allied Health Literature Plus, PsycINFO, Cochrane CENTRAL, and PubMed was conducted for studies published between March 2007 and March 2019. We looked for randomized controlled trials (RCTs) examining interventions delivered to adult cancer survivors via eHealth methods with a measure of health behavior change. Random-effects meta-analysis was performed to examine whether the method of eHealth delivery impacted the level of engagement, behavior change, and health outcomes. Results: A total of 24 RCTs were included predominantly examining dietary and physical activity behavior change interventions. There were 11 studies that used a synchronous approach and 11 studies that used an asynchronous approach, whereas 2 studies used a combined delivery method. Use of eHealth interventions improved exercise behavior (standardized mean difference [SMD] 0.34, 95% CI 0.21-0.48), diet behavior (SMD 0.44, 95% CI 0.18-0.70), fatigue (SMD 0.21, 95% CI −0.08 to 0.50; SMD change 0.22, 95% CI 0.09-0.35), anxiety (SMD 1.21, 95% CI: 0.36-2.07; SMD change 0.15, 95% CI −0.09 to 0.40), depression (SMD 0.15, 95% CI 0.00-0.30), and quality of life (SMD 0.12, 95% CI −0.10 to 0.34; SMD change 0.14, 95% CI 0.04-0.24). The mode of delivery did not influence the amount of dietary and physical activity behavior change observed. Conclusions: Physical activity and dietary behavior change eHealth interventions delivered to patients with cancer or survivors have a small to moderate impact on behavior change and a small to very small benefit to quality of life, fatigue, depression, and anxiety. There is insufficient evidence to determine whether asynchronous or synchronous delivery modes yield superior results. Three-arm RCTs comparing delivery modes with a control with robust engagement reporting are required to determine the most successful delivery method for promoting behavior change and ultimately favorable health outcomes.

Background: KRAS G12D mutation subtype is present in over 40% of pancreatic ductal adenocarcinoma (PDAC), one of the leading global causes of cancer death. This retrospective cohort study aims to investigate whether detection of the KRAS G12D mutation subtype in PDAC patients is a determinant of prognosis across all stages of disease. Methods: We reviewed the medical records of 231 patients presenting with PDAC at a large tertiary hospital, and compared survival using the Kaplan Meier, log-rank test and Cox proportional hazards regression model. Results: KRAS G12D mutation subtype was not significantly associated with poorer survival compared across the whole population of PDAC patients (p = 0.107; HR 1.293 95% CI (0.946–1.767)). However, KRAS G12D patients who were resectable had a shorter median survival time of 356 days compared to all other genotypes (median survival 810 days) (p = 0.019; HR 1.991 95% CI (1.121–3.537)). Conclusions: KRAS G12D patients who were resectable at diagnosis had shorter survival compared to all other PDAC patients. These data suggest that KRAS G12D may be a clinically useful prognostic biomarker of PDAC.

The molecular mechanism underlying the development of Barrett's esophagus (BE), the precursor to esophageal adenocarcinoma, remains unknown. Our previous work implicated sonic hedgehog (Shh) signaling as a possible driver of BE and suggested that bone morphogenetic protein 4 (Bmp4) and Sox9 were downstream mediators. We have utilized a novel in vivo tissue reconstitution model to investigate the relative roles of Bmp4 and Sox9 in driving metaplasia. Epithelia reconstituted from squamous epithelial cells or empty vector-transduced cells had a stratified squamous phenotype, reminiscent of normal esophagus. Expression of Bmp4 in the stromal compartment activated signaling in the epithelium but did not alter the squamous phenotype. In contrast, expression of Sox9 in squamous epithelial cells induced formation of columnar-like epithelium with expression of the columnar differentiation marker cytokeratin 8 and the intestinal-specific glycoprotein A33. In patient tissue, A33 protein was expressed specifically in BE, but not in normal esophagus. Expression of Cdx2, another putative driver of BE, alone had no effect on reconstitution of a squamous epithelium. Furthermore, epithelium coexpressing Cdx2 and Sox9 had a phenotype similar to epithelium expressing Sox9 alone. Our results demonstrate that Sox9 is sufficient to drive columnar differentiation of squamous epithelium and expression of an intestinal differentiation marker, reminiscent of BE. These data suggest that Shh-mediated expression of Sox9 may be an important early event in the development of BE and that the potential for inhibitors of the hedgehog pathway to be used in the treatment of BE and/or esophageal adenocarcinoma could be tested in the near future.