Christopher Y. Kang

Clinical Significance of Serum COL6A3 in Pancreatic Ductal Adenocarcinoma

Type VI collagen (COL6) forms a microfibrillar network often associated with type I collagen and constitutes a major component of the desmoplastic reaction in pancreatic ductal adenocarcinoma (PDA). We have demonstrated recently that the α3 chain of COL6, COL6A3, is highly expressed in PDA tissue and undergoes tumor-specific alternative splicing. In this study, we investigated the diagnostic value and clinical significance of circulating COL6A3 protein and mRNA in PDA. COL6A3 levels in sera from patients with PDA (n = 44), benign lesions (n = 46) and age-matched healthy volunteers (n = 30) were analyzed by enzyme-linked immunosorbent assays (ELISA). Predictive abilities of COL6A3 were examined using receiver operating characteristic (ROC) curves from logistic regression models for PDA versus normal or benign serum levels. Expression levels were correlated with clinicopathological parameters. Real-time PCR was used to analyze the presence of COL6A3 mRNA containing alternative spliced exons E3, E4, and E6. Circulating COL6A3 protein levels were significantly elevated in PDA patients when compared to healthy sera (p = 0.0001) and benign lesions (p = 0.0035). The overall area under the ROC was 0.975. Log(COL6A3) alone provided good discrimination between PDA and benign lesions (area under the curve (AUC) = 0.817), but combined with CA19-9 provided excellent discrimination (AUC = 0.904). Interestingly, high COL6A3 serum levels were significantly associated with perineural invasion and cigarette smoking. Combined E3, E4, and E6 serum RNA values provided good sensitivity but low specificity. Our data demonstrate for the first time the potential clinical significance of circulating COL6A3 in the diagnosis of pancreatic malignancy.

Conserved Metabolic Changes in Nondiabetic and Type 2 Diabetic Bariatric Surgery Patients: Global Metabolomic Pilot Study

The goal of this study was to provide insight into the mechanism by which bariatric surgical procedures led to weight loss and improvement or resolution of diabetes. Global biochemical profiling was used to evaluate changes occurring in nondiabetic and type 2 diabetic (T2D) patients experiencing either less extreme sleeve gastrectomy or a full gastric bypass. We were able to identify changes in metabolism that were affected by standard preoperation liquid weight loss diet as well as by bariatric surgery itself. Preoperation weight-loss diet was associated with a strong lipid metabolism signature largely related to the consumption of adipose reserves for energy production. Glucose usage shift away from glycolytic pyruvate production toward pentose phosphate pathway, via glucose-6-phosphate, appeared to be shared across all patients regardless of T2D status or bariatric surgery procedure. Our results suggested that bariatric surgery might promote antioxidant defense and insulin sensitivity through both increased heme synthesis and HO activity or expression. Changes in histidine and its metabolites following surgery might be an indication of altered gut microbiome ecology or liver function. This initial study provided broad understanding of how metabolism changed globally in morbidly obese nondiabetic and T2D patients following weight-loss surgery.

Perioperative use of the imacor hemodynamic transesophageal echocardiography probe in cardiac surgery patients: initial experience.

Echocardiography is the standard to assess heart function although obtaining transesophageal echocardiography (TEE) on an emergent basis may be limited by its availability. A transoral miniaturized hemodynamic TEE (hTEE) probe (ImaCor Inc.) was developed to provide direct visualization of the heart, and we hypothesized that the probe could provide hemodynamic information useful for patient management. Data from 2011 to 2012 was retrospectively collected. Four hundred ninety patients were treated in the cardiovascular intensive care unit of which 61 underwent hTEE monitoring and were divided into three groups: patients on extracorporeal membrane oxygenation (ECMO) (n = 25), ventricular assist device (VAD) (n = 6), and others (n = 30). Patient charts were reviewed to investigate the indications for the use of hTEE, findings, and the interventions performed. The indications for probe insertion were hemodynamic instability (n = 32), ECMO weaning (n = 10), VAD alarm (n = 1), tamponade (n = 14), pulmonary embolism (n = 2), and intra-aortic balloon pump wean (n = 2). In all 61 cases, we were successfully able to diagnose and treat the etiology of instability based on the hTEE findings. Utilization of the hTEE probe successfully diagnosed and aided therapy in all patients with hemodynamic instability refractory to initial therapy and provides a valuable tool to aid clinicians in the management of postoperative hemodynamics.

RAN GTPase and Osteopontin in Pancreatic Cancer

INTRODUCTION Pancreatic ductal adenocarcinoma (PDA) has the worst prognosis among cancers, mainly due to the high incidence of early metastases. RAN small GTPase (RAN) is a protein that plays physiological roles in the regulation of nuclear transport and microtubule spindle assembly. RAN was recently shown to mediate the invasive functions of the prometastatic protein osteopontin (OPN) in breast cancer cells. We and others have shown previously that high levels of OPN are present in PDA. In this study, we analyzed the expression and correlation of RAN with OPN in human pancreatic lesions, and explored their regulation in PDA cell lines. METHODS Real time PCR was used to analyze RAN and OPN mRNA levels in PDA, adjacent non-malignant, and benign pancreatic tissues. Expression levels were correlated with survival and different clinicopathological parameters using different statistical methods. Transient transfection studies using OPN and RAN plasmids, and knockdown experiments using siRNA were used to examine their mutual regulation. RESULTS OPN and RAN levels highly correlated with each other (p<0.0001). OPN or RAN levels did not correlate with venous lymphatic invasion, diabetes, obesity, T stage, BMI, or survival. However, we found a significant association between RAN levels and perineural invasion (HR=0.79, 95% CI 0.59, 1.07; p=0.0378.). OPN and RAN colocalized in PDA tissues and cell lines. Increasing RAN expression in PDA cells induced OPN transcription and RAN silencing reduced total OPN levels. OPN did not have any significant effect on RAN transcription. CONCLUSIONS The high levels of RAN in PDA and its correlation with OPN and with perineural invasion suggest that RAN may contribute to PDA metastasis and progression through the induction of OPN. RANs role in the regulation of OPN in PDA is unique and could provide potential novel therapeutic strategies to combat PDA aggressiveness.

Overexpressing TNF-Alpha in Pancreatic Ductal Adenocarcinoma Cells and Fibroblasts Modifies Cell Survival and Reduces Fatty Acid Synthesis via Downregulation of Sterol Regulatory Element Binding Protein-1 and Activation of Acetyl CoA Carboxylase

The effect of tumor necrosis factor-alpha (TNF-α) gene delivery has been suggested as a potentially useful therapeutic approach to improve the chemotherapeutic treatment of patients with pancreatic ductal adenocarcinoma (PDA), but the exact mechanism of its action is not clearly understood. In this study, we analyzed the expression profile of TNF-α in PDA tissue and explored its potential role in fatty acid synthase (FAS) regulation in PDA cells and in fibroblasts. Quantitative real-time polymerase chain reaction was used to examine the expression of TNF-α in PDA, matching adjacent tissues, and benign lesions. Logistic regression models with robust variance were used to analyze the gene expression levels, and Kaplan–Meier survival curves were generated. In vitro, we overexpressed the TNF-α gene in PDA cells and fibroblasts and analyzed its effect on cell survival, migration, and on members of the FAS signaling pathway. We also evaluated TNF-α effects on a panel of inflammation-, angiogenesis-, and metastasis-related markers. In the tumor tissue of PDA patients, compared with their matched adjacent tissue, expression levels of TNF-α were not statistically different and did not correlate with survival or any other examined clinicopathological features. Overexpression of TNF-α significantly (p < 0.05) reduced PDA and fibroblast cell migration. In PDA cells that highly overexpress TNF-α, this was associated with a significant reduction of FAS mRNA and protein expression levels and significant (p < 0.05) reduction of SREBP-1 and ACC mRNA. Reduction of FAS by TNF-α was inhibited when either SREBP-1 or ACC was knocked down by siRNA. PDA cells and fibroblasts that overexpress TNF-α displayed differential regulation of several inflammation-related markers and reduced levels of metastasis-related genes. Our data demonstrate a previously unknown multi-targeted involvement of TNF-α in PDA lipogenesis and inflammation and metastasis and suggest that intratumoral introduction of TNF-α may have the potential as a novel therapeutic approach in human PDA.

Hypothyroidism in Pancreatic Cancer: Role of Exogenous Thyroid Hormone in Tumor Invasion—Preliminary Observations

According to the epidemiological studies, about 4.4% of American general elderly population has a pronounced hypothyroidism and relies on thyroid hormone supplements daily. The prevalence of hypothyroidism in our patients with pancreatic cancer was much higher, 14.1%. A retrospective analysis was performed on patients who underwent pancreaticoduodenectomy (Whipple procedure) or distal pancreatectomy and splenectomy (DPS) at Thomas Jefferson University Hospital, Philadelphia, from 2005 to 2012. The diagnosis of hypothyroidism was correlated with clinicopathologic parameters including tumor stage, grade, and survival. To further understand how thyroid hormone affects pancreatic cancer behavior, functional studies including wound-induced cell migration, proliferation, and invasion were performed on pancreatic cancer cell lines, MiaPaCa-2 and AsPC-1. We found that hypothyroid patients taking exogenous thyroid hormone were more than three times likely to have perineural invasion, and about twice as likely to have higher T stage, nodal spread, and overall poorer prognostic stage (P < 0.05). Pancreatic cancer cell line studies demonstrated that exogenous thyroid hormone treatment increased cell proliferation, migration, and invasion (P < 0.05). We conclude that exogenous thyroid hormone may contribute to the progression of pancreatic cancer.

918 Overexpressing TNF-Alpha in Pancreatic Ductal Adenocarcinoma Cells and Fibroblasts Modifies Cell Survival and Reduces Fatty Acid Synthesis via Downregulation of Sterol Regulatory Element Binding Protein-1 and Activation of Acetyl CoA Carboxylase

The effect of tumor necrosis factor-alpha (TNF-α) gene delivery has been suggested as a potentially useful therapeutic approach to improve the chemotherapeutic treatment of patients with pancreatic ductal adenocarcinoma (PDA), but the exact mechanism of its action is not clearly understood. In this study, we analyzed the expression profile of TNF-α in PDA tissue and explored its potential role in fatty acid synthase (FAS) regulation in PDA cells and in fibroblasts. Quantitative real-time polymerase chain reaction was used to examine the expression of TNF-α in PDA, matching adjacent tissues, and benign lesions. Logistic regression models with robust variance were used to analyze the gene expression levels, and Kaplan–Meier survival curves were generated. In vitro, we overexpressed the TNF-α gene in PDA cells and fibroblasts and analyzed its effect on cell survival, migration, and on members of the FAS signaling pathway. We also evaluated TNF-α effects on a panel of inflammation-, angiogenesis-, and metastasis-related markers. In the tumor tissue of PDA patients, compared with their matched adjacent tissue, expression levels of TNF-α were not statistically different and did not correlate with survival or any other examined clinicopathological features. Overexpression of TNF-α significantly (p < 0.05) reduced PDA and fibroblast cell migration. In PDA cells that highly overexpress TNF-α, this was associated with a significant reduction of FAS mRNA and protein expression levels and significant (p < 0.05) reduction of SREBP-1 and ACC mRNA. Reduction of FAS by TNF-α was inhibited when either SREBP-1 or ACC was knocked down by siRNA. PDA cells and fibroblasts that overexpress TNF-α displayed differential regulation of several inflammation-related markers and reduced levels of metastasis-related genes. Our data demonstrate a previously unknown multi-targeted involvement of TNF-α in PDA lipogenesis and inflammation and metastasis and suggest that intratumoral introduction of TNF-α may have the potential as a novel therapeutic approach in human PDA.

Mo1839 Osteopontin (Opn) Isoforms, Diabetes, Obesity, and Cancer; What's One Got to Do With the Other? A New Role for Opn

Alternative splicing of osteopontin (OPN) produces three isoforms: OPNa, OPNb, and OPNc. The aims of this study were to examine the expression profile of OPN isoforms in sera from patients with pancreatic lesions and to determine their correlation with the presence of comorbid systemic inflammatory conditions, such as diabetes and/or obesity. Sera from 90 patients undergoing pancreatic surgery and 29 healthy volunteers were analyzed. Seventeen patients were diabetics, 17 were obese, and 6 had both diabetes and obesity. In patients with pancreatic lesions, OPNb was expressed in 48 % of the patients’ sera, OPNc in 34 %, and both in 5 %. The presence of diabetes and/or obesity was associated with complete disappearance of OPNb and expression of only OPNc. OPNc presence was significantly associated with diabetes and obesity (OR = 7.06 [95 % CI 1.97–23.3]; p = 0.003). No OPNb or OPNc was detected in the normal sera. Overexpression of OPNb and OPNc isoforms in PDA cells significantly (p < 0.05) increased their activity in soft-agar colony formation and wound healing assays, induced the transcription of interleukin (IL)-6, and reduced tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and IL-10. Our data show for the first time the significant association between serum OPNc and diabetes and/or obesity. Unraveling the functional role of OPN isoforms in systemic inflammation is essential to understanding their significance as therapeutic targets in diabetes and obesity, and during metastasis development in PDA.