Transcriptomic Analysis of Laser Capture Microdissected Tumors Reveals Cancer- and Stromal-Specific Molecular Subtypes of Pancreatic Ductal Adenocarcinoma.

PURPOSE: Pancreatic ductal adenocarcinoma (PDAC) lethality is multifactorial; although studies have identified transcriptional and genetic subsets of tumors with different prognostic significance, there is limited understanding of features associated with the minority of patients who have durable remission after surgical resection. In this study, we performed laser capture microdissection (LCM) of PDAC samples to define their cancer- and stroma-specific molecular subtypes and identify a prognostic gene expression signature for short-term and long-term survival. EXPERIMENTAL DESIGN: LCM and RNA sequencing (RNA-seq) analysis of cancer and adjacent stroma of 19 treatment-naïve PDAC tumors was performed. Gene expression signatures were tested for their robustness in a large independent validation set. An RNA-ISH assay with pooled probes for genes associated with disease-free survival (DFS) was developed to probe 111 PDAC tumor samples. RESULTS: Gene expression profiling identified four subtypes of cancer cells (C1-C4) and three subtypes of cancer-adjacent stroma (S1-S3). These stroma-specific subtypes were associated with DFS (P = 5.55E-07), with S1 associated with better prognoses when paired with C1 and C2. Thirteen genes were found to be predominantly expressed in cancer cells and corresponded with DFS in a validation using existing RNA-seq datasets. A second validation on an independent cohort of patients using RNA-ISH probes to six of these prognostic genes demonstrated significant association with overall survival (median 17 vs. 25 months; P < 0.02). CONCLUSIONS: Our results identified specific signatures from the epithelial and the stroma components of PDAC, which add clarity to the nature of PDAC molecular subtypes and may help predict survival.

Neoplastic-Stromal Cell Cross-talk Regulates Matrisome Expression in Pancreatic Cancer.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a highly desmoplastic reaction, warranting intense cancer-stroma communication. In this study, we interrogated the contribution of the BET family of chromatin adaptors to the cross-talk between PDAC cells and the tumor stroma. Short-term treatment of orthotopic xenograft tumors with CPI203, a small-molecule inhibitor of BET proteins, resulted in broad changes in the expression of genes encoding components of the extracellular matrix (matrisome) in both cancer and stromal cells. Remarkably, more than half of matrisome genes were expressed by cancer cells. In vitro cocultures of PDAC cells and cancer-associated fibroblasts (CAF) demonstrated that matrisome expression was regulated by BET-dependent cancer-CAF cross-talk. Disrupting this cross-talk in vivo resulted in diminished growth of orthotopic patient-derived xenograft tumors, reduced proliferation of cancer cells, and changes in collagen structure consistent with that of patients who experienced better survival. Examination of matrisome gene expression in publicly available data sets of 573 PDAC tumors identified a 65-gene signature that was able to distinguish long- and short-term PDAC survivors. Importantly, the expression of genes predictive of short-term survival was diminished in the cancer cells of orthotopic xenograft tumors of mice treated with CPI203. Taken together, these results demonstrate that inhibiting the activity BET proteins results in transcriptional and structural differences in the matrisome are associated with better patient survival. IMPLICATIONS: These studies highlight the biological relevance of the matrisome program in PDAC and suggest targeting of epigenetically driven tumor-stroma cross-talk as a potential therapeutic avenue.

FOLFIRINOX Versus Gemcitabine-based Therapy for Pancreatic Ductal Adenocarcinoma: Lessons from Patient-derived Cell Lines.

BACKGROUND/AIM: FOLFIRINOX [fluorouracil (5-FU), irinotecan, oxaliplatin] and gemcitabine plus nab-paclitaxel are standard treatments for patients with pancreatic ductal adenocarcinoma (PDAC). Despite efficacy rates of less than 32%, evidence is lacking to guide the use of one drug over the other. Herein, we compared the sensitivity of patient-derived PDAC cell lines to each of these regimens. MATERIALS AND METHODS: Changes in the growth of 19 low-passage patient-derived PDAC cell lines were evaluated in response to treatment with FOLFIRINOX and gemcitabine plus paclitaxel (Gem-Pac). RESULTS: Six cell lines exhibited optimal sensitivity (high EMax and low GI50) to FOLFIRINOX and three cell lines exhibited optimal sensitivity to Gem-Pac. Several cell lines that were optimally sensitive to one drug regimen exhibited very poor response to the other. CONCLUSION: Further characterization of cancer cells exhibiting preferential sensitivity to each of these regimens may allow the identification of biomarkers to guide the selection of appropriate chemotherapy for a given patient.

Determinants, time trends and dynamic consequences of postoperative hyperglycemia in nondiabetic patients undergoing major elective abdominal surgery: A prospective, longitudinal, observational evaluation.

BACKGROUND & AIMS: In retrospective studies an indisputable causal relationship between hyperglycemia and postoperative infections cannot be entirely disclaimed. We aimed investigate whether the time trends of blood glucose levels in the perioperative period could be a determinant of surgery-related infections. METHODS: Adult patients without diabetes who were candidates for elective major abdominal operation were prospectively enrolled in a longitudinal, observational multicenter study. The blood glucose level was measured every 6 h for 3 days. We calculated the association between blood glucose (BG) levels and the risk of occurrence of surgery-related infections using a joint regression modeling for longitudinal and time-to-event outcomes which accounts for the effect of other risk factors. RESULTS: Between January 2016 and November 2017, we obtained 6078 BG measures distributed on different time-points in 452 patients. There was a nearly 3-fold increased risk of having hyperglycemia, defined as BG ≥ 125 mg/dL, if the BG level at admission was >100 mg/dL (OR = 2.986, P < 0.001).The hazard of infection for each 10 mg/dL increase of BG levels over time was marginal (HR = 1.065, P = 0.045). The calculated risk of having an infection was 9.6% for BG going from 110 mg/dL during surgery to 84 mg/dL at the end of day 3, 10.5% for BG decreasing from 140 to 114, 11.8% for BG decreasing from 180 to 154 and 24.5% for BG increasing from 80 to 145, 24.7% for BG increasing from 110 to 175, and 25.4% for BG increasing from 140 to 205. CONCLUSIONS: The time trends of BG - as opposed to the absolute concentration -are major determinants of the risk of postoperative infections.