Jennifer W. Harris

An obligatory role for neurotensin in high-fat-diet-induced obesity

Obesity and its associated comorbidities (for example, diabetes mellitus and hepatic steatosis) contribute to approximately 2.5 million deaths annually and are among the most prevalent and challenging conditions confronting the medical profession. Neurotensin (NT; also known as NTS), a 13-amino-acid peptide predominantly localized in specialized enteroendocrine cells of the small intestine and released by fat ingestion, facilitates fatty acid translocation in rat intestine, and stimulates the growth of various cancers. The effects of NT are mediated through three known NT receptors (NTR1, 2 and 3; also known as NTSR1, 2, and NTSR3, respectively). Increased fasting plasma levels of pro-NT (a stable NT precursor fragment produced in equimolar amounts relative to NT) are associated with increased risk of diabetes, cardiovascular disease and mortality; however, a role for NT as a causative factor in these diseases is unknown. Here we show that NT-deficient mice demonstrate significantly reduced intestinal fat absorption and are protected from obesity, hepatic steatosis and insulin resistance associated with high fat consumption. We further demonstrate that NT attenuates the activation of AMP-activated protein kinase (AMPK) and stimulates fatty acid absorption in mice and in cultured intestinal cells, and that this occurs through a mechanism involving NTR1 and NTR3 (also known as sortilin). Consistent with the findings in mice, expression of NT in Drosophila midgut enteroendocrine cells results in increased lipid accumulation in the midgut, fat body, and oenocytes (specialized hepatocyte-like cells) and decreased AMPK activation. Remarkably, in humans, we show that both obese and insulin-resistant subjects have elevated plasma concentrations of pro-NT, and in longitudinal studies among non-obese subjects, high levels of pro-NT denote a doubling of the risk of developing obesity later in life. Our findings directly link NT with increased fat absorption and obesity and suggest that NT may provide a prognostic marker of future obesity and a potential target for prevention and treatment.

Cotargeting the PI3K and RAS Pathways for the Treatment of Neuroendocrine Tumors

Background: The precise involvement of the PI3K/mTOR and RAS/MEK pathways in carcinoid tumors is not well defined. Therefore, the purpose of our study was to evaluate the role these pathways play in carcinoid cell proliferation, apoptosis, and secretion and to determine the effects of combined treatment on carcinoid tumor inhibition. Methods: The human neuroendocrine cell lines BON (pancreatic carcinoid), NCI-H727 (lung carcinoid), and QGP-1 (somatostatinoma) were treated with either the pan-PI3K inhibitor, BKM120, or the dual PI3K–mTOR inhibitor, BEZ235, alone or in combination with the MEK inhibitor, PD0325901; proliferation, apoptosis, and protein expression were assessed. Peptide secretion was evaluated in BON and QGP-1 cells. The antiproliferative effect of BEZ235, alone or combined with PD0325901, was then tested in vivo. Results: Both BKM120 and BEZ235 decreased proliferation and increased apoptosis; combination with PD0325901 significantly enhanced the antineoplastic effects of either treatment alone. In contrast, neurotensin peptide secretion was markedly stimulated with BKM120 treatment, but not BEZ235. The combination of BEZ235 + PD0325901 significantly inhibited the growth of BON xenografts without systemic toxicity. Conclusions: Both BKM120 and BEZ235 effectively inhibited neuroendocrine tumor (NET) cell proliferation and stimulated apoptosis. However, inhibition of the PI3K pathway alone with BKM120 significantly stimulated neurotensin peptide secretion; this did not occur with the dual inhibition of both PI3K and mTOR using BEZ235 suggesting that this would be a more effective treatment regimen for NETs. Moreover, the combination of BEZ235 and the MEK inhibitor PD0325901 was a safe and more effective therapy in vivo compared with single agents alone. Clin Cancer Res; 20(5); 1212–22. ©2014 AACR.

Adipocytes activate mitochondrial fatty acid oxidation and autophagy to promote tumor growth in colon cancer

Obesity has been associated with increased incidence and mortality of a wide variety of human cancers including colorectal cancer. However, the molecular mechanism by which adipocytes regulate the metabolism of colon cancer cells remains elusive. In this study, we showed that adipocytes isolated from adipose tissues of colon cancer patients have an important role in modulating cellular metabolism to support tumor growth and survival. Abundant adipocytes were found in close association with invasive tumor cells in colon cancer patients. Co-culture of adipocytes with colon cancer cells led to a transfer of free fatty acids that released from the adipocytes to the cancer cells. Uptake of fatty acids allowed the cancer cells to survive nutrient deprivation conditions by upregulating mitochondrial fatty acid β-oxidation. Mechanistically, co-culture of adipocytes or treating cells with fatty acids induced autophagy in colon cancer cells as a result of AMPK activation. Inhibition of autophagy attenuated the ability of cancer cells to utilize fatty acids and blocked the growth-promoting effect of adipocytes. In addition, we found that adipocytes stimulated the expression of genes associated with cancer stem cells and downregulated genes associated with intestinal epithelial cell differentiation in primary colon cancer cells and mouse tumor organoids. Importantly, the presence of adipocytes promoted the growth of xenograft tumors in vivo. Taken together, our results show that adipocytes in the tumor microenvironment serve as an energy provider and a metabolic regulator to promote the growth and survival of colon cancer cells.

Ventral hernia: Patient selection, treatment, and management ☆

Ventral hernias are among the most common pathologic conditions seen by clinicians, with an estimated one fourth of all individuals being born with, developing, or acquiring a ventral hernia in their lifetime. Repair of ventral hernias is among the 5 most common procedures performed by a general surgeon, and it is estimated that in the United States more than

Increased morbidity and mortality of a concomitant colectomy during a pancreaticoduodenectomy: an NSQIP propensity-score matched analysis

3.4 billion will be spent this year on the surgical management of ventral hernias. These repairs are fraught with complications including surgical site infections (SSIs), wound complications, and hernia recurrences. Despite the increasing use of advanced surgical techniques, availability of modern prosthetic materials, and increasing understanding of ventral hernias, the long-term outcome for ventral hernia repair remains poor, with a 10-year failure rate (recurrence) of 30% in the simplest ventral hernia defects and more than 70% in more complex ventral hernias. One of the main reasons for persistently poor outcomes despite the advances made is the increasingly comorbid patient population. Within Westernized nations, obesity is a growing epidemic. In the United States, 66% of adults are overweight or obese. Patients with hernias typically have an even higher BMI, and

Deptor Is a Novel Target of Wnt/β-Catenin/c-Myc and Contributes to Colorectal Cancer Cell Growth

BACKGROUND Select patients with peri-ampullary cancers require concomitant colon resection (CR) during a pancreaticoduodenectomy (PD) for margin-negative resections. This study analysed the impact of concomitant CR on major morbidity (MM) and mortality. METHODS National Surgical Quality Improvement Program (NSQIP) patients undergoing PD for peri-ampullary cancers were identified from 2005 to 2012. A 4 : 1 propensity-score matched analysis isolated the impact of CR upon PD. Risk factors for 30-day MM and mortality were analysed to determine post-operative sequelae of PD+CR. RESULTS From 10 965 PD and 159 PD+CR patients, 624 and 156, respectively, were selected for 4 : 1 matched analysis. PD+CR resulted in a higher MM and mortality (50.0% and 9.0%) versus PD alone (28.8% and 2.9%, respectively, P < 0.001). Multivariate analysis identified risk factors for MM after PD: concomitant CR [odds ratio (OR)-3.19, P < 0.001], smoking (OR-1.92, P = 0.005), a lack of functional independence (OR-3.29, P = 0.018), cardiac disease (OR-2.39, P = 0.011), decreased albumin (per g/dl, OR-1.38, P = 0.033) and a longer operative time (versus median time, OR-1.56, P = 0.029). Independent predictors of mortality included concomitant CR (OR-3.16, P = 0.010), ventilator dependence (OR-13.87, P < 0.001) and septic shock (OR-6.02, P < 0.001). CONCLUSIONS CR was an independent predictor of MM and mortality after a PD. Patients requiring PD+CR should be identified pre-operatively, maximally optimized and referred to experienced surgeons at expert centres.

Temperature induces significant changes in both glycolytic reserve and mitochondrial spare respiratory capacity in colorectal cancer cell lines

Activation of the Wnt/β-catenin signaling pathway drives colorectal cancer growth by deregulating expression of downstream target genes, including the c-myc proto-oncogene. The critical targets that mediate the functions of oncogenic c-Myc in colorectal cancer have yet to be fully elucidated. Previously, we showed that activation of PI3K/Akt/mTOR contributes to colorectal cancer growth and metastasis. Here, we show that Deptor, a suppressor of mTOR, is a direct target of Wnt/β-catenin/c-Myc signaling in colorectal cancer cells. Inhibition of Wnt/β-catenin or knockdown of c-Myc decreased, while activation of Wnt/β-catenin or overexpression of c-Myc increased the expression of Deptor. c-Myc bound the promoter of Deptor and transcriptionally regulated Deptor expression. Inhibition of Wnt/β-catenin/c-Myc signaling increased mTOR activation, and the combination of Wnt and Akt/mTOR inhibitors enhanced inhibition of colorectal cancer cell growth in vitro and in vivo Deptor expression was increased in colorectal cancer cells; knockdown of Deptor induced differentiation, decreased expression of B lymphoma Mo-MLV insertion region 1 (Bmi1), and decreased proliferation in colorectal cancer cell lines and primary human colorectal cancer cells. Importantly, our work identifies Deptor as a downstream target of the Wnt/β-catenin/c-Myc signaling pathway, acting as a tumor promoter in colorectal cancer cells. Moreover, we provide a molecular basis for the synergistic combination of Wnt and mTOR inhibitors in treating colorectal cancer with elevated c-Myc.Significance: The mTOR inhibitor DEPTOR acts as a tumor promoter and could be a potential therapeutic target in colorectal cancer. Cancer Res; 78(12); 3163-75. ©2018 AACR.

Preclinical evaluation of novel fatty acid synthase inhibitors in primary colorectal cancer cells and a patient-derived xenograft model of colorectal cancer

Abstract Thermotherapy, as a method of treating cancer, has recently attracted considerable attention from basic and clinical investigators. A number of studies and clinical trials have shown that thermotherapy can be successfully used as a therapeutic approach for various cancers. However, the effects of temperature on cancer bioenergetics have not been studied in detail with a real time, microplate based, label‐free detection approach. This study investigates how changes in temperature affect the bioenergetics characteristics (mitochondrial function and glycolysis) of three colorectal cancer (CRC) cell lines utilizing the Seahorse XF96 technology. Experiments were performed at 32 °C, 37 °C and 42 °C using assay medium conditions and equipment settings adjusted to produce equal oxygen and pH levels ubiquitously at the beginning of all experiments. The results suggest that temperature significantly changes multiple components of glycolytic and mitochondrial function of all cell lines tested. Under hypothermia conditions (32 °C), the extracellular acidification rates (ECAR) of CRC cells were significantly lower compared to the same basal ECAR levels measured at 37 °C. Mitochondrial stress test for SW480 cells at 37 °C vs 42 °C demonstrated increased proton leak while all other OCR components remained unchanged (similar results were detected also for the patient‐derived xenograft cells Pt.93). Interestingly, the FCCP dose response at 37 °C vs 42 °C show significant shifts in profiles, suggesting that single dose FCCP experiments might not be sufficient to characterize the mitochondrial metabolic potential when comparing groups, conditions or treatments. These findings provide valuable insights for the metabolic and bioenergetic changes of CRC cells under hypo‐ and hyperthermia conditions that could potentially lead to development of better targeted and personalized strategies for patients undergoing combined thermotherapy with chemotherapy.

Necrotizing Fasciitis of the Breast Requiring Emergent Radical Mastectomy.

Fatty Acid Synthase (FASN), a key enzyme of de novo lipogenesis, is upregulated in many cancers including colorectal cancer (CRC); increased FASN expression is associated with poor prognosis. Potent FASN inhibitors (TVBs) developed by 3-V Biosciences demonstrate anti-tumor activity in vitro and in vivo and a favorable tolerability profile in a Phase I clinical trial. However, CRC characteristics associated with responsiveness to FASN inhibition are not fully understood. We evaluated the effect of TVB-3664 on tumor growth in nine CRC patient-derived xenografts (PDXs) and investigated molecular and metabolic changes associated with CRC responsiveness to FASN inhibition. CRC cells and PDXs showed a wide range of sensitivity to FASN inhibition. TVB-3664 treatment showed significant response (reduced tumor volume) in 30% of cases. Anti-tumor effect of TVB-3664 was associated with a significant decrease in a pool of adenine nucleotides and alterations in lipid composition including a significant reduction in fatty acids and phospholipids and an increase in lactosylceramide and sphingomyelin in PDXs sensitive to FASN inhibition. Moreover, Akt, Erk1/2 and AMPK were major oncogenic pathways altered by TVBs. In summary, we demonstrated that novel TVB inhibitors show anti-tumor activity in CRC and this activity is associated with a decrease in activation of Akt and Erk1/2 oncogenic pathways and significant alteration of lipid composition of tumors. Further understanding of genetic and metabolic characteristics of tumors susceptible to FASN inhibition may enable patient selection and personalized medicine approaches in CRC.

Abstract B54: The role of fatty acid synthase in regulation of autophagy in colorectal cancer

Necrotizing fasciitis is a rare, aggressive, soft‐tissue infection that results in necrosis of skin, subcutaneous tissue, and fascia. It spreads rapidly and may progress to sepsis, multi‐organ failure, and death. Predisposing conditions include diabetes, chronic alcoholism, advanced age, vascular disease, and immunosuppression and many cases are preceded by an injury or invasive procedure. Necrotizing soft‐tissue infection of the breast is uncommon, with only a few reported cases in the literature. We present a 53‐year‐old diabetic woman who presented to the emergency room with several weeks of worsening breast and shoulder pain, swelling, and erythema. Upon formal evaluation by the surgical service, a necrotizing soft‐tissue infection was suspected, and the patient was scheduled for emergent, surgical debridement. Because of the aggressive nature and high mortality of this disease, immediate surgical intervention, coupled with antibiotic therapy and physiologic support, is necessary to prevent complications and death.