Possible enhancing activity of diacylglycerol on 4-nitroquinoline 1-oxide induced carcinogenesis of the tongue in human c-Ha-ras proto-oncogene transgenic rats

Obesity: An emerging driver of head and neck cancer

Obesity has become pandemic and emerged as one of the most critical global health care problems worldwide since last century. Recent studies have demonstrated that there may be a causal link between obesity and higher risks and mortality of cancers, including prostate, breast, colon, and thyroid cancers, head and neck cancer (HNC). This review focuses on the relationship between obesity and HNC, and the molecular mechanism of abnormal lipid metabolism in HNC. Elucidating the mechanism may open up new possibilities for strategies to reduce risk and mortality of HNC in an increasingly obese population.

A decision tree-based integrated testing strategy for tailor-made carcinogenicity evaluation of test substances using genotoxicity test results and chemical spaces

Genotoxicity evaluation has been widely used to estimate the carcinogenicity of test substances during safety evaluation. However, the latest strategies using genotoxicity tests give more weight to sensitivity; therefore, their accuracy has been very low. For precise carcinogenicity evaluation, we attempted to establish an integrated testing strategy for the tailor-made carcinogenicity evaluation of test materials, considering the relationships among genotoxicity test results (Ames, in vitro mammalian genotoxicity and in vivo micronucleus), carcinogenicity test results and chemical properties (molecular weight, logKow and 179 organic functional groups). By analyzing the toxicological information and chemical properties of 230 chemicals, including 184 carcinogens in the Carcinogenicity Genotoxicity eXperience database, a decision tree for carcinogenicity evaluation was optimised statistically. A decision forest model was generated using a machine-learning method-random forest-which comprises thousands of decision trees. As a result, balanced accuracies in cross-validation of the optimised decision tree and decision forest model, considering chemical space (71.5% and 75.5%, respectively), were higher than balanced accuracy of an example regulatory decision tree (54.1%). Moreover, the statistical optimisation of tree-based models revealed significant organic functional groups that would cause false prediction in standard genotoxicity tests and non-genotoxic carcinogenicity (e.g., organic amide and thioamide, saturated heterocyclic fragment and aryl halide). In vitro genotoxicity tests were the most important parameters in all models, even when in silico parameters were integrated. Although external validation is required, the findings of the integrated testing strategies established herein will contribute to precise carcinogenicity evaluation and to determine new mechanistic hypotheses of carcinogenicity.

Differential Expression of Prostaglandin I2 Synthase Associated with Arachidonic Acid Pathway in the Oral Squamous Cell Carcinoma

Introduction

Differential expression of genes encoding cytochrome P450 (CYP) and other oxygenases enzymes involved in biotransformation mechanisms of endogenous and exogenous compounds can lead to oral tumor development.

Objective

We aimed to identify the expression profile of these genes, searching for susceptibility biomarkers in oral squamous cell carcinoma.

Patients and Methods

Sixteen oral squamous cell carcinoma samples were included in this study (eight tumor and eight adjacent non-tumor tissues). Gene expression quantification was performed using TaqMan Array Human CYP450 and other Oxygenases 96-well plate (Applied Biosystems) by real time qPCR. Protein quantification was performed by ELISA and IHC methods. Bioinformatics tools were used to find metabolic pathways related to the enzymes encoded by differentially expressed genes. Results. CYP27B1, CYP27A1, CYP2E1, CYP2R1, CYP2J2, CYP2U1, CYP4F12, CYP4X1, CYP4B1, PTGIS, ALOX12, and MAOB genes presented differential expression in the oral tumors. After correction by multiple tests, only the PTGIS (Prostaglandin I2 Synthase) gene presented significant differential expression (P < 0.05). The PTGIS gene and protein were reduced in oral tumors.

Conclusion

PTGIS presents downexpression in oral tumors. PTGIS play an important role in the arachidonic acid metabolism. Arachidonic acid and/or metabolites are derived from this pathway, which can influence the regulation of important physiological mechanisms in tumorigenesis process.

Alpha-linolenic acid-enriched diacylglycerol oil does not promote tumor development in tongue and gastrointestinal tract tissues in a medium-term multi-organ carcinogenesis bioassay using male F344 rat

Alpha-linolenic acid (ALA)-enriched diacylglycerol (DAG) oil is an edible oil enriched with DAG (>80%) and ALA (>50%). The present study investigated whether ALA-DAG oil promotes tumorigenesis in the tongue and gastrointestinal tract, using a rat medium-term multi-organ carcinogenesis bioassay model. Rats were treated with five genotoxic carcinogens to induce multi-organ tumorigenesis until week 4, and from 1 week after withdrawal, fed a semi-synthetic diet (AIN-93G) containing ALA-DAG oil at concentrations of 0, 13,750, 27,500, and 55,000 ppm. Rats fed AIN-93G containing 55,000 ppm ALA-triacylglycerol or a standard basal diet served as reference and negative control groups, respectively. Animals were euthanized at week 30. ALA-DAG oil was shown to have no effects on survival, general condition, body weight, food consumption, or organ weight. More discolored spots were observed in the stomachs of the 13,750- and 55,000-ppm ALA-DAG groups than in those of the control groups; however, there were no differences in the frequency of histopathological findings across groups. There were no meaningful increases in the incidence of pre-neoplastic and neoplastic lesions in the tongue and gastrointestinal tract among the groups. We therefore conclude that ALA-DAG oil does not promote tumor development in the digestive system.

A pioneering epidemiological study investigating the incidence of squamous cell carcinoma of tongue in a Portuguese population

Objective: The purpose of this study was to investigate the incidence of squamous cell carcinoma (SCC) of the anterior two thirds of the tongue in a population living in central and southern Portugal, all treated at Portuguese Institute of Oncology of Lisbon, Francisco Gentil (IPOLFG). Study Design: This study was a retrospective review of all patients who had a histopathological diagnosis of SCC of the anterior two thirds of the tongue and had been treated in the Head and Neck Surgery Unit at the IPOLFG (Lisbon, Portugal), between 1st January 2001 and 31st December 2009. The risk factors evaluated were: gender; age; alcohol consumption; tobacco use; prosthesis use and the carcinoma site. Results: Of the 424 cases analyses, 71% were men. Mean age of occurrence was in 5th decade for males and the 6th decade for females, and the border of the tongue was the most common location. Alcohol consumption and tobacco had a lower impact in women, being the most common etiological factors in the male population. No significant association was observed between patients and the use of a prosthesis. Conclusions: In spite of the consumption of aohol and tobacco starting to decline in certain parts of the world, our findings showed both factors still have a significant impact in male population. Further research should be done to determine etiological factors in females.

Key words:Squamous cell carcinoma, tongue, epidemiology, Portuguese population.

Diacylglycerol oil for the metabolic syndrome

Excess adiposity has been shown to play a crucial role in the development of the metabolic syndrome. The elevated fasting and postprandial triglyceride-rich lipoprotein levels is the central lipid abnormality observed in the metabolic syndrome. Recent studies have indicated that diacylglycerol (DAG) is effective for fasting and postprandial hyperlipidemia and preventing excess adiposity by increasing postprandial energy expenditure. We will here discuss the mechanisms of DAG-mediated improvements in hyperlipidemia and in postprandial energy expenditure, and effects of DAG oil on lipid/glucose metabolism and on body fat. Further, the therapeutic application of DAG for the metabolic syndrome will be considered.