Combinatorial Gli activity directs immune infiltration and tumor growth in pancreatic cancer.

Proper Hedgehog (HH) signaling is essential for embryonic development, while aberrant HH signaling drives pediatric and adult cancers. HH signaling is frequently dysregulated in pancreatic cancer, yet its role remains controversial, with both tumor-promoting and tumor-restraining functions reported. Notably, the GLI family of HH transcription factors (GLI1, GLI2, GLI3), remain largely unexplored in pancreatic cancer. We therefore investigated the individual and combined contributions of GLI1-3 to pancreatic cancer progression. At pre-cancerous stages, fibroblast-specific Gli2/Gli3 deletion decreases immunosuppressive macrophage infiltration and promotes T cell infiltration. Strikingly, combined loss of Gli1/Gli2/Gli3 promotes macrophage infiltration, indicating that subtle changes in Gli expression differentially regulate immune infiltration. In invasive tumors, Gli2/Gli3 KO fibroblasts exclude immunosuppressive myeloid cells and suppress tumor growth by recruiting natural killer cells. Finally, we demonstrate that fibroblasts directly regulate macrophage and T cell migration through the expression of Gli-dependent cytokines. Thus, the coordinated activity of GLI1-3 directs the fibroinflammatory response throughout pancreatic cancer progression.

ATDC induces an invasive switch in KRAS-induced pancreatic tumorigenesis.

The initiation of pancreatic ductal adenocarcinoma (PDA) is linked to activating mutations in KRAS. However, in PDA mouse models, expression of oncogenic mutant KRAS during development gives rise to tumors only after a prolonged latency or following induction of pancreatitis. Here we describe a novel mouse model expressing ataxia telangiectasia group D complementing gene (ATDC, also known as TRIM29 [tripartite motif 29]) that, in the presence of oncogenic KRAS, accelerates pancreatic intraepithelial neoplasia (PanIN) formation and the development of invasive and metastatic cancers. We found that ATDC up-regulates CD44 in mouse and human PanIN lesions via activation of ß-catenin signaling, leading to the induction of an epithelial-to-mesenchymal transition (EMT) phenotype characterized by expression of Zeb1 and Snail1. We show that ATDC is up-regulated by oncogenic Kras in a subset of PanIN cells that are capable of invading the surrounding stroma. These results delineate a novel molecular pathway for EMT in pancreatic tumorigenesis, showing that ATDC is a proximal regulator of EMT.

Survival benefit with adjuvant radiotherapy after resection of distal cholangiocarcinoma: A propensity-matched National Cancer Database analysis.

BACKGROUND: No convincing evidence for the benefit of adjuvant radiotherapy (RT) following resection of distal cholangiocarcinoma (dCCA) exists, especially for lower-risk (margin- or node-negative) disease. Hence, the association of adjuvant RT on survival after surgical resection of dCCA was compared with no adjuvant RT (noRT). METHODS: Using National Cancer Database data from 2004 to 2016, patients undergoing pancreatoduodenectomy for nonmetastatic dCCA were identified. Patients with neoadjuvant RT and chemotherapy and survival <6 months were excluded. Propensity score matching was used to account for treatment-selection bias. A multivariable Cox proportional hazards model was then used to analyze the association of adjuvant RT with survival. RESULTS: Of 2162 (34%) adjuvant RT and 4155 (66%) noRT patients, 1509 adjuvant RT and 1509 noRT patients remained in the cohort after matching. The rates of node-negative disease (N0), node-positive disease (N+), and unknown node status (Nx) were 39%, 51%, and 10%, respectively. After matching, adjuvant RT was associated with improved survival (median, 29.3 vs 26.8 months; P < .001), which remained after multivariable adjustment (HR, 0.86; 95% CI, 0.80-0.93; P < .001). Multivariable interaction analyses showed this benefit was seen irrespective of nodal status (N0: HR, 0.77; 95% CI, 0.66-0.89; P < .001; N+: HR, 0.79; 95% CI, 0.71-0.89; P < .001) and margin status (R0: HR, 0.58; 95% CI, 0.50-0.67; P < .001; R1: HR, 0.87; 95% CI, 0.78-0.96; P = .007). Stratified analyses by nodal and margin status demonstrated consistent results. CONCLUSIONS: Adjuvant RT after dCCA resection was associated with a survival benefit in patients, even in patients with margin- or node-negative resections. Adjuvant RT should be considered routinely irrespective of margin and nodal status after resection for dCCA. LAY SUMMARY: Adjuvant radiotherapy after resection of distal cholangiocarcinoma was associated with a survival benefit in patients, even in patients with margin-negative or node-negative resections. Adjuvant radiotherapy should be considered routinely irrespective of margin and nodal status after resection of distal cholangiocarcinoma.

Association of Adjuvant Radiotherapy With Survival After Margin-negative Resection of Pancreatic Ductal Adenocarcinoma: A Propensity-matched National Cancer Database (NCDB) Analysis.

INTRODUCTION: There is conflicting evidence for the benefit of adjuvant radiotherapy (RT) after resection of pancreatic ductal adenocarcinoma (PDAC), especially for margin-negative (R0) resections. We aimed to evaluate the association of adjuvant RT with survival after R0 resection of PDAC. METHODS: Using National Cancer Database (NCDB) data from 2004 to 2013, we identified patients with R0 resection of nonmetastatic PDAC. Patients with neoadjuvant radiotherapy and chemotherapy and survival <6 months were excluded. Propensity score matching was used to account for treatment selection bias. A multivariable Cox proportional hazards model was then used to analyze the association of RT with survival. RESULTS: Of 4547 (36%) RT and 7925 (64%) non-RT patients, 3860 RT and 3860 non-RT patients remained in the cohort after matching. Clinicopathologic and demographic variables were well balanced after matching. Lymph node metastases were present in 68% (44% N1, 24% N2). After matching, RT was associated with higher survival (median 25.8 vs 23.9 mo, 5-yr 27% vs 24%, P < 0.001). After multivariable adjustment, RT remained associated with a survival benefit (HR 0.89, 95% CI 0.84-0.94, P < 0.001). Stratified and multivariable interaction analyses showed that this benefit was restricted to patients with node-positive disease: N1 (HR: 0.68, CI95%: 0.62-0.76, P = 0.007) and N2 (HR: 0.59, CI95%: 0.54-0.64, P = 0.04). CONCLUSIONS: In this large retrospective cohort study, adjuvant RT after R0 PDAC resection was associated with a survival benefit in patients with node-positive disease. Adjuvant RT should be considered after R0 resection of PDAC with node-positive disease.

Teamwork at the Bench: Strategies for Collaborative Surgical Science in a Pandemic.

The Center for Basic and Translational Science was formed to address the unique challenges faced by surgeon-scientists. Shortly after its inception, COVID-19 upended research workflows at our institution. We discuss how the collaborative Center for Basic and Translational Science framework was adapted to support laboratories during the pandemic by assisting with ramp-down, promoting mentorship and community building, and maintaining research productivity.

Immunotherapy for pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) remains a lethal cancer with an urgent need for better medical therapies. Efforts have been made to investigate the efficacy of immunotherapy, particularly given the hallmarks of immune suppression and exhaustion in PDAC tumors. Here, we review the molecular components responsible for the immune-privileged state in PDAC and provide an overview of the immunotherapeutic strategies for PDAC including vaccine therapy, checkpoint blockade, myeloid-targeted therapy, and immune agonist therapy.

Repeat Cytoreductive Surgery-Hyperthermic Intraperitoneal Chemoperfusion is Feasible and Offers Survival Benefit in Select Patients with Peritoneal Metastases.

INTRODUCTION: We hypothesized that repeat cytoreductive surgery-hyperthermic intraperitoneal chemoperfusion (CRS-HIPEC) for peritoneal metastases (PM) may be associated with suboptimal resection, more frequent postoperative complications, and worse oncologic outcomes. METHODS: Using a prospectively maintained database, we compared clinicopathologic, perioperative, and oncologic outcome data in patients undergoing single or repeat CRS-HIPEC procedures. The Kaplan-Meier method was used to estimate survival. Multivariate analyses identified associations with perioperative and oncologic outcomes. RESULTS: Of the 1294 patients undergoing CRS-HIPEC procedures at our institution, only one CRS-HIPEC procedure (single HIPEC cohort) was performed in 1169 patients (90.3%), whereas 125 patients (9.7%) underwent repeat CRS-HIPEC procedures (repeat HIPEC cohort). Of the 1440 CRS-HIPEC procedures at our institution, a first CRS-HIPEC procedure was performed in 1294 patients (89.9%), whereas subsequent second, third, and fourth CRS-HIPEC procedures were performed in 125 patients (8.7%), 18 patients (1.3%), and 3 patients (0.2%), respectively. Progression-free survival (PFS) following the second CRS-HIPEC procedure was negatively impacted by shorter PFS following the first CRS-HIPEC procedure, independent of other significant variables related to the second procedure, including completeness of cytoreduction and postoperative complications. Patients undergoing multiple CRS-HIPEC procedures were not at higher risk for suboptimal resection or postoperative complications and demonstrated equivalent PFS following each successive procedure compared to the first procedure. CONCLUSIONS: Repeat CRS-HIPEC procedures for PM were not associated with suboptimal perioperative and oncologic outcomes. Our data confirmed our ability to select patients appropriately for repeat CRS-HIPEC procedures.

Analysis of Predictors of Resection and Survival in Locally Advanced Stage III Pancreatic Cancer: Does the Nature of Chemotherapy Regimen Influence Outcomes?

BACKGROUND: Locally advanced unresectable pancreatic cancer (LAPC) historically portends a poor prognosis. FOLFIRINOX and gemcitabine/nab-paclitaxel have proven effective in the metastatic setting. We sought to evaluate the outcomes of these regimens compared with older regimens in LAPC. METHODS: A retrospective, single institutional review of all consecutive LAPC treated with "new" (FOLFIRINOX and/or gemcitabine/nab-paclitaxel) and "old" (gemcitabine or 5-FU) chemotherapy from 2010 to 2014 was performed. Univariate and multivariate predictors of resection and survival were determined. RESULTS: A total of 92 patients (new chemotherapy = 61, old chemotherapy = 31) were analyzed, of which 19 (21%) underwent eventual resection (median overall survival [OS] = 32 vs. 14.3 months for unresected patients, P = 0.0002). For the overall cohort, resection (hazard ratio [HR] 0.261, P = 0.014), radiation therapy (HR 0.458, P = 0.004), number of lines of chemotherapy (HR 0.486, P = 0.012), and new chemotherapy (HR 0.593 vs. old regimens, P = 0.065) were independent predictors of OS on multivariate analyses (MVA). On MVA, predictors of eventual resection were head and neck tumors (OR 0.307, P = 0.033) or SMA involvement (OR 0.285, P = 0.023). In nonresected patients (73), MVA showed treatment with new chemotherapy (HR 0.452, P = 0.006), radiation (HR 0.459, P = 0.006), and number of lines of CT (HR 0.705, P = 0.013) to be predictors of survival. CONCLUSIONS: In LAPC, use of FOLFIRNOX and/or gemcitabine/nab-paclitaxel is associated with improved survival compared with older chemotherapy regimens, regardless of eventual resection. Tumor location and relationship to certain vasculature are important determinants of resection in this cohort.

Cross-desensitization of CCR1, but not CCR2, following activation of the formyl peptide receptor FPR1.

The cross-regulation of G protein-coupled receptors (GPCRs) plays an important role in the immune response. Studies from several laboratories have suggested that a hierarchy of sensitivities to cross-desensitization exists for the chemoattractant GPCRs. We carried out experiments to study the capacity of the formyl peptide receptor-1 (FPR1) to desensitize chemokine receptors CCR1 and CCR2. Our results show that activation of FPR1 resulted in the desensitization and partial internalization of CCR1, but not CCR2, in both primary human monocytes and HEK293 cells coexpressing CCR1, CCR2, and FPR1 (HR1R2F cells). The desensitization of CCR1 by FPR1 stimulation was not due to the simple depletion of the Ca(2+) stores, but was dependent on activation of protein kinase C. Furthermore, we found that the cross-desensitization of CCR1 by FPR1 was associated with CCR1 phosphorylation and moderate reduction of CCR1 cell-surface expression. In contrast, CCR2 was not phosphorylated or internalized after FPR1 activation. Additional studies showed that optimal cross talk between FPR1 and CCR1 was dependent on the functional activity of protein kinase Cß. These results provide a mechanistic basis for the capacity of certain GPCR ligands to exert rapid and selective cross-inactivation of other chemoattractant receptors, and suggest that FPR1 is able to exert "traffic control" in the migration of inflammatory cells by rapidly inhibiting the cell responses to potentially "low-priority" chemoattractants such as CCR1 agonists without inhibiting the response to "higher priority" CCR2 chemoattractants.

Bmi1 is required for the initiation of pancreatic cancer through an Ink4a-independent mechanism.

Epigenetic dysregulation is involved in the initiation and progression of many epithelial cancers. BMI1, a component of the polycomb protein family, plays a key role in these processes by controlling the histone ubiquitination and long-term repression of multiple genomic loci. BMI1 has previously been implicated in pancreatic homeostasis and the function of pancreatic cancer stem cells. However, no work has yet addressed its role in the early stages of pancreatic cancer development. Here, we show that BMI1 is required for the initiation of murine pancreatic neoplasia using a novel conditional knockout of Bmi1 in combination with a Kras(G12D)-driven pancreatic cancer mouse model. We also demonstrate that the requirement for Bmi1 in pancreatic carcinogenesis is independent of the Ink4a/Arf locus and at least partially mediated by dysregulation of reactive oxygen species. Our data provide new evidence of the importance of this epigenetic regulator in the genesis of pancreatic cancer.

Recent advances in pancreatic surgery.

PURPOSE OF REVIEW: To appraise the recent literature dealing with important advances in the field of pancreatic surgery. RECENT FINDINGS: Surgical care for pancreatic cancer patients remains fractured, with imperfect patient selection and ongoing bias in referral patterns based on socioeconomic factors. Analysis of readmissions after pancreatectomy reveals it to be a poor quality of care metric. More extensive pancreatic resections lead to higher morbidity. Intraductal papillary mucinous neoplasm and pancreatic neuroendocrine tumor biology affect patient outcomes and suggest the need for better diagnostic approaches for these entities. Perioperative drainage still has a role during Whipple pancreaticoduodenectomy on the basis of the results of a randomized controlled trial. Laparoscopic and robotic approaches married with new emerging technologies have the potential to transform the practice of pancreatic surgery. SUMMARY: Pancreatic surgery is a rapidly evolving field with the promise to significantly improve outcomes for patients with a variety of pancreatic diseases in the future.

From Inception to Malignancy: the Co-evolution of Pancreatic Cancer and Its Immunosuppressive Microenvironment.

Published in Cancer Research in 2007, Clark and colleagues first introduced the concept that the immune microenvironment evolves in lockstep with the progression of pancreatic cancer. Leveraging genetically engineered mouse models of the disease that were described a few years earlier, Clark and colleagues used a combination of approaches to describe the dynamics of immune evolution in precursor lesions all the way to overt malignancy. They discovered that immunosuppression is established at the earliest stages of carcinogenesis. Here, we discuss their findings, how they led to a wealth of functional work, and how they have been expanded upon since the advent of -omics technologies. See related article by Clark and colleagues, Cancer Res 2007;67:9518-27.

Characterization of undifferentiated carcinomas of the pancreas with and without osteoclast-like giant cells.

BACKGROUND: Undifferentiated carcinoma (UC) is a rare subtype of pancreatic cancer differentiated from UC with osteoclast-like giant cells (UC-OGC) in 2019, impacting interpretation of literature that does not distinguish these subtypes. We sought to identify translationally relevant differences between these two variants and as compared to pancreatic ductal adenocarcinoma (PDAC). METHODS: We characterized clinical and multiomic differences between UC (n = 32) and UC-OGC (n = 15) using DNA-sequencing (seq), RNA-seq, and multiplex immunofluorescence (mIF) and compared these findings to PDAC. RESULTS: Characteristics at diagnosis were similar between UC and UC-OGC, though UC-OGC was more resectable (p = .009). Across all stages, median overall survival (OS) was shorter for UC than UC-OGC (0.4 vs 10.8 years, respectively; p = .003). This shorter survival was retained after stratification by resection, albeit without statistical significance (1.8 vs 11.9 years, respectively; p = .08). In a subset of patients with available tissue, the genomic landscape was similar between UC (n = 9), UC-OGC (n = 5), and PDAC (n = 159). Bulk RNA-seq was deconvoluted and, along with mIF in UC (n = 13), UC-OGC (n = 5), and PDAC (n = 16), demonstrated statistically significantly increased antigen-presenting cells (APCs), including M2 macrophages and NK cells, and decreased cytotoxic and regulatory T cells (Tregs) in UC and UC-OGC vs PDAC. Findings were similar between UC and UC-OGC except decreased Tregs in UC-OGC (p = .04). CONCLUSIONS: In this series, UC is more aggressive than UC-OGC with these variants having more APCs and fewer Tregs than PDAC, suggesting potential for immune-modulating therapies in treatment of these pancreatic cancer subtypes.

Notch Signaling Regulates Immunosuppressive Tumor-Associated Macrophage Function in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDA) continues to have a dismal prognosis. The poor survival of patients with PDA has been attributed to a high rate of early metastasis and low efficacy of current therapies, which partly result from its complex immunosuppressive tumor microenvironment. Previous studies from our group and others have shown that tumor-associated macrophages (TAM) are instrumental in maintaining immunosuppression in PDA. Here, we explored the role of Notch signaling, a key regulator of immune response, within the PDA microenvironment. We identified Notch pathway components in multiple immune cell types within human and mouse pancreatic cancer. TAMs, the most abundant immune cell population in the tumor microenvironment, expressed high levels of Notch receptors, with cognate ligands such as JAG1 expressed on tumor epithelial cells, endothelial cells, and fibroblasts. TAMs with activated Notch signaling expressed higher levels of immunosuppressive mediators, suggesting that Notch signaling plays a role in macrophage polarization within the PDA microenvironment. Genetic inhibition of Notch in myeloid cells led to reduced tumor size and decreased macrophage infiltration in an orthotopic PDA model. Combination of pharmacologic Notch inhibition with PD-1 blockade resulted in increased cytotoxic T-cell infiltration, tumor cell apoptosis, and smaller tumor size. Our work implicates macrophage Notch signaling in the establishment of immunosuppression and indicates that targeting the Notch pathway may improve the efficacy of immune-based therapies in patients with PDA.

ROR2 Regulates Cellular Plasticity in Pancreatic Neoplasia and Adenocarcinoma.

Cellular plasticity is a hallmark of pancreatic ductal adenocarcinoma (PDAC) starting from the conversion of normal cells into precancerous lesions, to the progression of carcinoma subtypes associated with aggressiveness and therapeutic response. We discovered that normal acinar cell differentiation, maintained by the transcription factor Pdx1, suppresses a broad gastric cell identity that is maintained in metaplasia, neoplasia, and the classical subtype of PDAC in mouse and human. We have identified the receptor tyrosine kinase Ror2 as marker of a gastric metaplasia-like identity in pancreas neoplasms. Ablation of Ror2 in a mouse model of pancreatic tumorigenesis promoted a switch to a gastric pit cell identity that largely persisted through progression to the classical subtype of PDAC. In both human and mouse pancreatic cancer, ROR2 activity continued to antagonize the gastric pit cell identity, strongly promoting an epithelial to mesenchymal transition, conferring resistance to KRAS inhibition, and vulnerability to AKT inhibition.

ROR2 regulates cellular plasticity in pancreatic neoplasia and adenocarcinoma.

Cellular plasticity is a hallmark of pancreatic ductal adenocarcinoma (PDAC) starting from the conversion of normal cells into precancerous lesions to the progression of carcinoma subtypes associated with aggressiveness and therapeutic response. We discovered that normal acinar cell differentiation, maintained by the transcription factor Pdx1, suppresses a broad gastric cell identity that is maintained in metaplasia, neoplasia, and the classical subtype of PDAC in mouse and human. We have identified the receptor tyrosine kinase Ror2 as marker of a gastric metaplasia (SPEM)-like identity in the pancreas. Ablation of Ror2 in a mouse model of pancreatic tumorigenesis promoted a switch to a gastric pit cell identity that largely persisted through progression to the classical subtype of PDAC. In both human and mouse pancreatic cancer, ROR2 activity continued to antagonize the gastric pit cell identity, strongly promoting an epithelial to mesenchymal transition, conferring resistance to KRAS inhibition, and vulnerability to AKT inhibition.

Oncogenic KRAS-Dependent Stromal Interleukin-33 Directs the Pancreatic Microenvironment to Promote Tumor Growth.

Pancreatic cancer is characterized by an extensive fibroinflammatory microenvironment. During carcinogenesis, normal stromal cells are converted to cytokine-high cancer-associated fibroblasts (CAF). The mechanisms underlying this conversion, including the regulation and function of fibroblast-derived cytokines, are poorly understood. Thus, efforts to therapeutically target CAFs have so far failed. Herein, we show that signals from epithelial cells expressing oncogenic KRAS-a hallmark pancreatic cancer mutation-activate fibroblast autocrine signaling, which drives the expression of the cytokine IL33. Stromal IL33 expression remains high and dependent on epithelial KRAS throughout carcinogenesis; in turn, environmental stress induces interleukin-33 (IL33) secretion. Using compartment-specific IL33 knockout mice, we observed that lack of stromal IL33 leads to profound reprogramming of multiple components of the pancreatic tumor microenvironment, including CAFs, myeloid cells, and lymphocytes. Notably, loss of stromal IL33 leads to an increase in CD8+ T-cell infiltration and activation and, ultimately, reduced tumor growth. Significance: This study provides new insights into the mechanisms underlying the programming of CAFs and shows that during this process, expression of the cytokine IL33 is induced. CAF-derived IL33 has pleiotropic effects on the tumor microenvironment, supporting its potential as a therapeutic target.