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.

Differential effects of soybean and fenugreek extracts on the growth of MCF-7 cells.

The effect of aqueous and ethanol extracts of soybean and fenugreek on the growth of MCF-7 cells, an estrogen receptor positive breast cancer cell line, has been examined in this study. Soybean is well known for the presence of phytoestrogens and fenugreek is reported to have medicinal use including anticancer properties. In a dose dependent manner soybean aqueous and ethanol extract promoted the growth and DNA synthesis in MCF-7 cells. On the contrary ethanol extract of fenugreek decreased the cell viability and induced early apoptotic changes such as flipping of phosphatidylserine and decrease of mitochondrial membrane potential. Degradation of cellular DNA into fragments comprising multiples of approximately 180-200 base pair was also observed. Cell cycle analysis by flow cytometry showed the presence of a subG1 apoptotic population which was more prominent at higher concentrations along with cell cycle arrest at G2/M phase. Our experiments show that while the soybean extract acts as a promoter of MCF-7 cell growth, the fenugreek extract induces apoptosis.

Membrane estrogen receptors: genomic actions and post transcriptional regulation.

The primary cellular location of the nuclear estrogen receptor II (nER II) is the plasma membrane. A number of reports that have appeared in the recent past indicate that plasma membrane localized estrogen receptor alpha (ERalpha) also exists. Whether the membrane localized ERalpha represents the receptor that binds to the estrogen responsive element (ERE) remains to be known. The mechanisms that underlie the internalization of nER II (non-activated estrogen receptor, deglycosylated) have been identified to a certain extent. The question remains: is the primary location of the ERalpha also the plasma membrane? If that is the case, it will be a challenging task to identify the molecular events that underlie the plasma membrane-to-nucleus movement of ERalpha. The internalization mechanisms for the two 66kDa plasma membrane ERs, following hormone binding, appear to be distinct and without any overlaps. Interestingly, while the major gene regulatory role for ERalpha appears to be at the level of transcription, the nER II has its major functional role in post transcriptional mechanisms. The endoplasmic reticulum associated anchor protein-55 (ap55) that was recently reported from the author's laboratory needs a closer look. It is a high affinity estrogen binding protein that anchors the estrogen receptor activation factor (E-RAF) in an estrogen-mediated event. It will be interesting to examine whether ap55 bears any structural similarity with either ERalpha or ERbeta.