Ceramides Increase Fatty Acid Utilization in Intestinal Progenitors to Enhance Stemness and Increase Tumor Risk.

BACKGROUND & AIMS: Cancers of the alimentary tract, including esophageal adenocarcinomas, colorectal cancers, and cancers of the gastric cardia, are common comorbidities of obesity. Prolonged, excessive delivery of macronutrients to the cells lining the gut can increase one's risk for these cancers by inducing imbalances in the rate of intestinal stem cell proliferation vs differentiation, which can produce polyps and other aberrant growths. We investigated whether ceramides, which are sphingolipids that serve as a signal of nutritional excess, alter stem cell behaviors to influence cancer risk. METHODS: We profiled sphingolipids and sphingolipid-synthesizing enzymes in human adenomas and tumors. Thereafter, we manipulated expression of sphingolipid-producing enzymes, including serine palmitoyltransferase (SPT), in intestinal progenitors of mice, cultured organoids, and Drosophila to discern whether sphingolipids altered stem cell proliferation and metabolism. RESULTS: SPT, which diverts dietary fatty acids and amino acids into the biosynthetic pathway that produces ceramides and other sphingolipids, is a critical modulator of intestinal stem cell homeostasis. SPT and other enzymes in the sphingolipid biosynthesis pathway are up-regulated in human intestinal adenomas. They produce ceramides, which serve as prostemness signals that stimulate peroxisome-proliferator activated receptor-α and induce fatty acid binding protein-1. These actions lead to increased lipid utilization and enhanced proliferation of intestinal progenitors. CONCLUSIONS: Ceramides serve as critical links between dietary macronutrients, epithelial regeneration, and cancer risk.

Survival Trends for Resectable Pancreatic Cancer Using a Multidisciplinary Conference: the Impact of Post-operative Chemotherapy.

PURPOSE: Despite advances in various treatment modalities, surgical resection for pancreatic ductal adenocarcinoma (PDA) remains the only curative treatment. Data remains limited regarding survival rates for resectable PDA when managed by a multidisciplinary pancreas conference (MDPC). The aim of this study is to assess survival rates, identify significant predictors of mortality, and assess the benefits of adjuvant chemotherapy for resectable PDA following presentation at a MDPC. METHODS: All patients presented from April 2013 to August 2016 with resectable PDA were discussed at a MDPC at a tertiary care center and were followed prospectively until November 2017. Survival analysis was performed using Kaplan-Meier for age, tumor size, tumor differentiation, T-stage, lymph node status, and completion of adjuvant chemotherapy cycles. Independent predictors of survival were determined using multivariate Cox regression modeling. RESULTS: After MDPC consensus and exclusions, total of 64 patients underwent successful surgery. Amongst this cohort, 1-, 2-, and 3-year survival was 78.13%, 46.30%, and 27.27%, respectively. A total of 37 patients (58%) initiated and 16 patients (25%) finished chemotherapy following surgery. Log-rank analysis revealed that tumor size, age, surgical margins, lymph node status, and number of adjuvant chemotherapy cycles received significantly influenced post-operative survival. Tumor size (p < 0.001), lymph node status (p = 0.035), and number of adjuvant chemotherapy cycles (p = 0.041) remained significant after multivariate Cox regression model. CONCLUSIONS: Our results suggest that patients with PDA with tumor size > 50 mm and/or lymph node involvement have poor outcomes despite being surgically resectable. Successful completion of adjuvant chemotherapy has better survival outcomes as compared with incomplete or no adjuvant chemotherapy. The role of alternative management such as down-staging with neoadjuvant therapy should be considered.

Identification of a Paracrine Signaling Mechanism Linking CD34high Progenitors to the Regulation of Visceral Fat Expansion and Remodeling.

Accumulation of visceral (VIS) is a predictor of metabolic disorders and insulin resistance. This is due in part to the limited capacity of VIS fat to buffer lipids allowing them to deposit in insulin-sensitive tissues. Mechanisms underlying selective hypertrophic growth and tissue remodeling properties of VIS fat are not well understood. We identified subsets of adipose progenitors (APs) unique to VIS fat with differential Cd34 expression and adipogenic capacity. VIS low (Cd34 low) APs are adipogenic, whereas VIS high (Cd34 high) APs are not. Furthermore, VIS high APs inhibit adipogenic differentiation of SUB and VIS low APs in vitro through the secretion of soluble inhibitory factor(s). The number of VIS high APs increased with adipose tissue expansion, and their abundance in vivo caused hypertrophic growth, fibrosis, inflammation, and metabolic dysfunction. This study unveils the presence of APs unique to VIS fat involved in the paracrine regulation of adipogenesis and tissue remodeling.

Performance of a Multidisciplinary Pancreatic Cancer Conference in Predicting and Managing Resectable Pancreatic Cancer.

OBJECTIVES: Surgery is the curative treatment for pancreatic ductal adenocarcinoma (PDA). Guidelines recommend utilizing a multidisciplinary pancreatic cancer conference (MDPC) in treatment; however, data are limited. The objective of this study was to assess the accuracy of an MDPC. METHODS: Patients with PDA presented at an MDPC were prospectively collected from April 2013 to August 2016. Patients were included if the MDPC predicted them to have resectable PDA and underwent upfront surgery. Secondary aims were to compare differences in tumor characteristics, time to surgery, and resection rates with patients prior to MDPC implementation (pre-MDPC). RESULTS: A total of 278 patients were presented at the MDPC. After excluding borderline and nonresectable cases, 91 patients were predicted as resectable on evaluation, and 70 were fit for surgery. The MDPC predicted resection in 91.4%. The MDPC had larger tumor size (32.6 vs 24.0 mm), greater proportion of stage II tumor, and a shorter time from diagnosis to resection (27.3 vs 35.5 days) compared with the pre-MDPC. Microscopically negative resections were similar between MDPC and pre-MDPC (85.9% vs 88.0%) despite advanced tumor size and stage. CONCLUSIONS: The MDPC demonstrates a high resection rate. Compared with a pre-MDPC, MDPC provides shorter time to surgery and selects for advanced tumors.

Evaluation of Multiple Biological Therapies for Ischemic Cardiac Disease.

The development of cell- and gene-based strategies for regenerative medicine offers a therapeutic option for the repair and potential regeneration of damaged cardiac tissue post-myocardial infarction (MI). Human umbilical cord subepithelial cell-derived stem cells (hUC-SECs), human bone marrow-derived mesenchymal stem cells (hBM-MSCs), and human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs), all derived from human tissue, have been shown to have in vitro and in vivo therapeutic potential. Additionally, S100a1, VEGF165, and stromal-derived factor-1α (SDF-1α) genes all have the potential to improve cardiac function and/or effect adverse remodeling. In this study, we compared the therapeutic potential of hBM-MSCs, hUC-SECs, and hiPSC-CMs along with plasmid-based genes to evaluate the in vivo potential of intramyocardially injected biologics to enhance cardiac function in a mouse MI model. Human cells derived from various tissue types were expanded under hypoxic conditions and injected intramyocardially into mice that had undergone left anterior descending (LAD) artery ligation. Similarly, plasmids were also injected into three groups of mice after LAD ligation. Seven experimental groups were studied in total: (1) control (saline), (2) hBM-MSCs, (3) hiPSC-CMs, (4) hUC-SECs, (5) S100a1 plasmid, (6) VEGF165 plasmid, and (7) SDF-1α plasmid. We evaluated echocardiography, hemodynamic catheterization measurements, and histology at 4 and 12 weeks post-biologic injection. Significant improvement was observed in cardiac function and contractility in hiPSC-CM and S100a1 groups and a significant reduction in left ventricle scar within the hUC-SEC group and a slight improvement in the SDF-1α and VEGF165 groups compared to the control group. These results demonstrate the potential for new biologic therapies to reduce scar burden and improve contractile function.

Metastatic malignant melanoma of the gallbladder presenting as biliary colic: a case report and review of literature.

Malignant melanoma (MM) is the most common cancer to metastasize to the gastrointestinal tract. Autopsy reports estimate that up to 15 per cent of these patients also have gallbladder metastases, and MM accounts for up to 60 per cent of metastatic lesions to the gallbladder. However, despite its prevalence, MM to the gallbladder is reported only sparingly in the literature. This discordance may be explained by the fact that these lesions are seldom symptomatic. Abdominal ultrasound remains the modality of choice in studying gallbladder pathology and has the ability to define metastatic lesions. The effect of screening for gallbladder metastases on improving survival is not well defined, and thus its role remains controversial. Cholecystectomy for melanoma metastases to the gallbladder seems to be mostly palliative, although there have been isolated reports of excellent long-term survival outcomes. The role for immunotherapy and chemotherapy in this population is not well defined, and overall prognosis is poor. Recent reports have advocated laparoscopic cholecystectomy as the treatment of choice, though there remains a concern for peritoneal port site seeding. We present the case of a 48-year-old man with MM metastatic to the gallbladder and a brief review of the literature.