Tumor engraftment in patient-derived xenografts of pancreatic ductal adenocarcinoma is associated with adverse clinicopathological features and poor survival

Patient-derived xenograft (PDX) tumors are powerful tools to study cancer biology. However, the ability of PDX tumors to model the biological and histological diversity of pancreatic ductal adenocarcinoma (PDAC) is not well known. In this study, we subcutaneously implanted 133 primary and metastatic PDAC tumors into immunodeficient mice. Fifty-seven tumors were successfully engrafted and even after extensive passaging, the histology of poorly-, moderately-, and well-differentiated tumors was maintained in the PDX models. Moreover, the fibroblast and collagen contents in the stroma of patient tumors were recapitulated in the corresponding PDX models. Analysis of the clinicopathological features of patients revealed xenograft tumor engraftment was associated with lymphovascular invasion (P = 0.001) and worse recurrence-free (median, 7 vs. 16 months, log-rank P = 0.047) and overall survival (median, 13 vs. 21 months, log-rank P = 0.038). Among successful engraftments, median time of growth required for reimplantation into new mice was 151 days. Reflective of the inherent biological diversity between PDX tumors with rapid (<151 days) and slow growth, differences in their growth were maintained during extensive passaging. Rapid growth was additionally associated with lymph node metastasis (P = 0.022). The association of lymphovascular invasion and lymph node metastasis with PDX formation and rapid growth may reflect an underlying biological mechanism that allows these tumors to adapt and grow in a new environment. While the ability of PDX tumors to mimic the cellular and non-cellular features of the parental tumor stroma provides a valuable model to study the interaction of PDAC cells with the tumor microenvironment, the association of successful engraftment with adverse clinicopathological features suggests PDX models over represent more aggressive forms of this disease

Black bean extract ameliorates liver fibrosis in rats with CCl4-induced injury

We assessed the anti-fibrotic effects of methanolic black bean extract antioxidants in a carbon tetrachloride (CCl4) liver injury model in rats. Experimentally intoxicated animals received CCl4 for eight weeks, the reference and test groups received daily intragastric quercetin or daily intragastric black bean extract. Liver fibrosis was assessed and quantified using morpho-metric analysis. Expression of fibrosis related genes was measured by real time RT-PCR. Qualitative and quantitative histological analysis showed that administration of 70 mg/kg b.w. of black bean extract reduced hepatic fibrosis index by 18% compared to positive controls (P 0.006), as a result of a decrease in type I (44.3% less, P 0.03) and type IV (68.9% less, P 0.049) collagen gene expression compared to CCl4-injured and Quercetin treated rats. In conclusion, we provide evidence that this methanol black bean extract ameliorates liver fibrosis and types I and IV collagen gene expression, in the animal model used.Practical applications: The compounds contained in this black bean extract exhibited strong antifibrotic effects in the CCl4 chronic liver injury model used; considering that this compounds are contained in a leguminous that has been used in human diet for a long time, their toxic potential should be very low, and this characteristic should favor their potential use in some other chronic or degenerative states that include an increase in inflammation and oxidative burst in their pathogenesis. Another possible application of this kind of extract could be its use as an antimicrobial or even antiparasitic therapeutic agent, although it is purely speculative

Medical care costs incurred by patients with smoking-related non-small cell lung cancer treated at the National Cancer Institute of Mexico

Background Smoking is a public health problem in Mexico and worldwide; its economic impact on developing countries has not been well documented. The aim of this study was to assess the direct medical costs attributable to smoking incurred by lung cancer patients treated at the National Cancer Institute of Mexico (INCan). Methods The study was conducted at INCan in 2009. We carried out a cost of illness (COI) methodology, using data derived from an expert panel consensus and from medical chart review. A panel of experts developed a diagnostic-therapeutic guide that combined the hospital patient pathways and the infrastructure, human resources, technology, and services provided by the medical units at INCan. Cost estimates in Mexican pesos were adjusted by inflation and converted into US Dollars using the 2013 FIX exchange rate for foreign transactions (1 USD = 13.06 Mexican pesos). Results A 297 incident cases diagnosed with any type of lung cancer were analyzed. According to clinical stage, the costs per patient were 13,456; 35,648; 106,186; and 144,555 USD, for lung cancer stages I, II, III, and IV respectively. The weighted average annual cost/patient was and 139,801 USD and the average annual cost/patient that was attributable to smoking was 92,269 USD. This cost was independent of the clinical stage, with stage IV representing 96% of the annual cost. The total annual cost of smoking-related lung cancer at INCan was 19,969,781 USD. Conclusions The medical care costs of lung cancer attributable to smoking represent a high cost both for INCan and the Mexican health sector. These costs could be reduced if all provisions established in the Framework Convention of Tobacco Control of the World Health Organization were implemented in Mexico

Critical role for arginase 2 in obesity-associated pancreatic cancer

Obesity is an established risk factor for pancreatic ductal adenocarcinoma (PDA). Despite recent identification of metabolic alterations in this lethal malignancy, the metabolic dependencies of obesity-associated PDA remain unknown. Here we show that obesity-driven PDA exhibits accelerated growth and a striking transcriptional enrichment for pathways regulating nitrogen metabolism. We find that the mitochondrial form of arginase (ARG2), which hydrolyzes arginine into ornithine and urea, is induced upon obesity, and silencing or loss of ARG2 markedly suppresses PDA. In vivo infusion of 15N-glutamine in obese mouse models of PDA demonstrates enhanced nitrogen flux into the urea cycle and infusion of 15N-arginine shows that Arg2 loss causes significant ammonia accumulation that results from the shunting of arginine catabolism into alternative nitrogen repositories. Furthermore, analysis of PDA patient tumors indicates that ARG2 levels correlate with body mass index (BMI). The specific dependency of PDA on ARG2 rather than the principal hepatic enzyme ARG1 opens a therapeutic window for obesity-associated pancreatic cancer