We found that the cancerous pancreas harbors a markedly more abundant microbiome compared with normal pancreas in both mice and humans, and select bacteria are differentially increased in the tumorous pancreas compared with gut. Ablation of the microbiome protects against preinvasive and invasive pancreatic ductal adenocarcinoma (PDA), whereas transfer of bacteria from PDA-bearing hosts, but not controls, reverses tumor protection. Bacterial ablation was associated with immunogenic reprogramming of the PDA tumor microenvironment, including a reduction in myeloid-derived suppressor cells and an increase in M1 macrophage differentiation, promoting TH1 differentiation of CD4 T cells and CD8 T-cell activation. Bacterial ablation also enabled efficacy for checkpoint-targeted immunotherapy by upregulating PD-1 expression. Mechanistically, the PDA microbiome generated a tolerogenic immune program by differentially activating select Toll-like receptors in monocytic cells. These data suggest that endogenous microbiota promote the crippling immune-suppression characteristic of PDA and that the microbiome has potential as a therapeutic target in the modulation of disease progression. We found that a distinct and abundant microbiome drives suppressive monocytic cellular differentiation in pancreatic cancer via selective Toll-like receptor ligation leading to T-cell anergy. Targeting the microbiome protects against oncogenesis, reverses intratumoral immune tolerance, and enables efficacy for checkpoint-based immunotherapy. These data have implications for understanding immune suppression in pancreatic cancer and its reversal in the clinic. .

Purpose GVAX pancreas, granulocyte-macrophage colony-stimulating factor–secreting allogeneic pancreatic tumor cells, induces T-cell immunity to cancer antigens, including mesothelin. GVAX is administered with low-dose cyclophosphamide (Cy) to inhibit regulatory T cells. CRS-207, live-attenuated Listeria monocytogenes–expressing mesothelin, induces innate and adaptive immunity. On the basis of preclinical synergy, we tested prime/boost vaccination with GVAX and CRS-207 in pancreatic adenocarcinoma. Patients and Methods Previously treated patients with metastatic pancreatic adenocarcinoma were randomly assigned at a ratio of 2:1 to two doses of Cy/GVAX followed by four doses of CRS-207 (arm A) or six doses of Cy/GVAX (arm B) every 3 weeks. Stable patients were offered additional courses. The primary end point was overall survival (OS) between arms. Secondary end points were safety and clinical response. Results A total of 90 patients were treated (arm A, n = 61; arm B, n = 29); 97% had received prior chemotherapy; 51% had received ≥ two regimens for metastatic disease. Mean number of doses (± standard deviation) administered in arms A and B were 5.5 ± 4.5 and 3.7 ± 2.2, respectively. The most frequent grade 3 to 4 related toxicities were transient fevers, lymphopenia, elevated liver enzymes, and fatigue. OS was 6.1 months in arm A versus 3.9 months in arm B (hazard ratio [HR], 0.59; P = .02). In a prespecified per-protocol analysis of patients who received at least three doses (two doses of Cy/GVAX plus one of CRS-207 or three of Cy/GVAX), OS was 9.7 versus 4.6 months (arm A v B; HR, 0.53; P = .02). Enhanced mesothelin-specific CD8 T-cell responses were associated with longer OS, regardless of treatment arm. Conclusion Heterologous prime/boost with Cy/GVAX and CRS-207 extended survival for patients with pancreatic cancer, with minimal toxicity.

PurposeSonic hedgehog (SHH), an activating ligand of smoothened (SMO), is overexpressed in > 70% of pancreatic cancers (PCs). We investigated the impact of vismodegib, an SHH antagonist, plus gemcitabine (GV) or gemcitabine plus placebo (GP) in a multicenter phase Ib/randomized phase II trial and preclinical PC models.Patients and MethodsPatients with PC not amenable to curative therapy who had received no prior therapy for metastatic disease and had Karnofsky performance score ≥ 80 were enrolled. Patients were randomly assigned in a one-to-one ratio to GV or GP. The primary end point was progression-free-survival (PFS). Exploratory correlative studies included serial SHH serum levels and contrast perfusion computed tomography imaging. To further investigate putative biologic mechanisms of SMO inhibition, two autochthonous pancreatic cancer models (KrasG12D; p16/p19fl/fl; Pdx1-Cre and KrasG12D; p53R270H/wt; Pdx1-Cre) were studied.ResultsNo safety issues were identified in the phase Ib portion (n = 7), and the phase II study enrolled 106 evaluable patients (n = 53 in each arm). Median PFS was 4.0 and 2.5 months for GV and GP arms, respectively (95% CI, 2.5 to 5.3 and 1.9 to 3.8, respectively; adjusted hazard ratio, 0.81; 95% CI, 0.54 to 1.21; P = .30). Median overall survival (OS) was 6.9 and 6.1 months for GV and GP arms, respectively (95% CI, 5.8 to 8.0 and 5.0 to 8.0, respectively; adjusted hazard ratio, 1.04; 95% CI, 0.69 to 1.58; P = .84). Response rates were not significantly different. There were no significant associations between correlative markers and overall response rate, PFS, or OS. Preclinical trials revealed no significant differences with vismodegib in drug delivery, tumor growth rate, or OS in either model.ConclusionThe addition of vismodegib to gemcitabine in an unselected cohort did not improve overall response rate, PFS, or OS in patients with metastatic PC. Our preclinical and clinical results revealed no statistically significant differences with respect to drug delivery or treatment efficacy using vismodegib.

The evolution of more sophisticated imaging techniques has initiated a renewed interest in stereotactic devices, methods, and applications. The Brown-Roberts-Wells instrument was available to us early in its prototype stage, and this report reviews the first 500 cases using the system at the University of Southern California Medical Center Hospitals. Procedures were undertaken after recognition of apparent structural alterations on imaging studies, with objectives being both diagnostic and therapeutic. Target locations were predominantly within the cerebral centrum-basal ganglia (284 cases) and diencephalic-mesencephalic regions (129 cases). Operative objectives included: histological and microbiological assay, cyst and abscess aspiration, installation of temporary or permanent drainage conduits, point source and colloid base brachytherapy, cerebroscopy and ventriculoscopy with biopsy, aspiration, and excision, and intraoperative vascular localization. Using multiple instrumentation at the target point (741 point placements), we realized procedural objectives in 95.6% of the cases. The mortality was 0.2% and the morbidity was 1%: hematoma, 2 cases; infection, 1 case; increased deficit, 1 case; intraprocedural seizure, 1 case. A specific diagnosis was not obtained in 4.4% (necrosis, 10 cases; inflammatory response, 9 cases; granuloma, 1 case; gliosis, 1 case; diagnostic error, 1 case). Individual guidelines for case selection, technique, institutional requirements, and applications of the method are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Purpose Gastric cancers (GC) may harbor a small subset of cells with cancer stem cell (CSC) properties including chemotherapy (CT) resistance. The Hedgehog (HH) pathway is a key developmental pathway that can be subverted by CSCs during tumorigenesis. Here we examine the role of HH signaling in CD44(+) GC cells. Experimental Design GC cell lines, tumor xenografts, and patient tumors were examined. Results GC cell lines AGS, MKN-45, and NCI-N87 grown as spheroids or sorted for CD44(+) were found to have upregulation of HH pathway proteins. HH inhibition using Smo shRNA or vismodegib (VIS) decreased spheroid formation and colony formation. CD44(+) cells, compared to unselected cells, were also resistant to 5-fluorouracil and cisplatin CT, and this resistance was reversed in vitro and in xenografts with Smo shRNA or VIS. CD44(+) cells also had significantly more migration, invasion, and anchorage-independent growth, and these properties could all be blocked with HH inhibition. Clinical tumor samples from a phase II trial for advanced GC of CT with or without VIS were analyzed for CD44 expression. In the CT alone group, high CD44 expression was associated with decreased survival, while in the CT plus VIS group, high CD44 expression was associated with improved survival. Conclusions HH signaling maintains CSC phenotypes and malignant transformation phenotypes in CD44(+) GC cells, and HH inhibition can block CT resistance in CD44(+) cells. GC is a heterogeneous disease, and the strategy of combining CT with HH inhibition may only be effective in the subset with high CD44 levels.

Summary Pancreatic ductal adenocarcinoma (PDA) is characterized by immune-tolerance and immunotherapeutic resistance. We discovered upregulation of receptor-interacting serine/threonine-protein kinase 1 (RIP1) in tumor-associated macrophages (TAMs) in PDA. To study its role in oncogenic progression, we developed a selective small molecule RIP1 inhibitor with high in vivo exposure. Targeting RIP1 reprogrammed TAMs toward an MHCIIhiTNFα+IFNγ+ immunogenic phenotype in a STAT1-dependent manner. RIP1 inhibition in TAMs resulted in cytotoxic T cell activation and T-helper cell differentiation towards a mixed Th1/Th17 phenotype, leading to tumor-immunity in mice and in organotypic models of human PDA. Targeting RIP1 synergized with PD1- and ICOS-based immunotherapies. Tumor-promoting effects of RIP1 were independent of its co-association with RIP3. Collectively, our work describes RIP1 as a checkpoint kinase governing tumor-immunity.

No abstract

Despite overall progress in the therapy of local and locally advanced esophageal, gastroesophageal junction, and gastric adenocarcinomas, death as a result of these tumors remains a common outcome. Most randomized phase III trials on which level-one evidence has been built have included the heterogeneous histologies and locations associated with these tumors. However, the different etiologies, molecular biology, and recurrence patterns associated with gastroesophageal malignancies suggest the need to split rather than lump. Biologic and response differences exist between squamous and adenocarcinomas, as well as diffuse and intestinal histologies. This may be a cause behind conflicting outcomes in similar trials. The accepted standard of chemoradiotherapy for locally advanced esophageal and gastroesophageal junction cancers is based on a few positive trials, with the best chemotherapy and total dose of radiation remaining controversial. In the West, the staging evaluations of locally advanced gastric cancer are not uniform. Yet, these evaluations will inform the results of preoperative and perioperative treatments. Although postoperative chemoradiotherapy for gastric cancer has been an accepted treatment option for the last decade, more recent studies have called into question the need for radiotherapy. In perioperative strategies, it has yet to be determined whether histologic or molecular changes in the operative specimen should inform postoperative treatment. An appropriate place for targeted therapy needs to be found in preoperative and postoperative treatment regimens. Finally, because so much is lost when trials are forced to close for lack of accrual, it is imperative to build multidisciplinary consensus before they are launched.