The Strange Case of Orotic Acid: The Different Expression of Pyrimidines Biosynthesis in Healthy Males and Females.

Orotic acid (OA) is an intermediate metabolite of pyrimidine nucleotide biosynthesis and represents a minor diet constituent. The measurement of urinary orotic acid is useful in confirming the diagnosis of hereditary metabolic diseases. Moreover, it could be of interest to know how the physiological concentration of this metabolite changes in relation to different conditions of clinical normality. The purpose of this study was to determine the orotic acid concentration in the urine of healthy patients, to observe normal oroticuria and to evaluate if the expression of pyrimidine intermediate biosynthesis differs between healthy males and females. The orotic acid concentration in urine was performed via the ICH M10-validated analytical method. Unexpectedly, females showed a greater oroticuria than males in pediatric age (0-10); conversely, we did not find significant differences until 70 years of age. The LC-MS/MS method was suitable for use in the differential diagnosis of hereditary metabolic disease and metabolic monitoring of anticancer drug-induced toxicity. The analytical protocol was found to be rapid and ideal, and was used in the routine analysis of a clinical chemistry laboratory. The biochemical aspects related to the expression of pyrimidine biosynthesis should be further investigated in light of the obtained results.

Endogenous glutamine decrease is associated with pancreatic cancer progression.

Pancreatic ductal adenocarcinoma (PDAC) is becoming the second leading cause of cancer-related death in the Western world. The mortality is very high, which emphasizes the need to identify biomarkers for early detection. As glutamine metabolism alteration is a feature of PDAC, its in vivo evaluation may provide a useful tool for biomarker identification. Our aim was to identify a handy method to evaluate blood glutamine consumption in mouse models of PDAC. We quantified the in vitro glutamine uptake by Mass Spectrometry (MS) in tumor cell supernatants and showed that it was higher in PDAC compared to non-PDAC tumor and pancreatic control human cells. The increased glutamine uptake was paralleled by higher activity of most glutamine pathway-related enzymes supporting nucleotide and ATP production. Free glutamine blood levels were evaluated in orthotopic and spontaneous mouse models of PDAC and other pancreatic-related disorders by High-Performance Liquid Chromatography (HPLC) and/or MS. Notably we observed a reduction of blood glutamine as much as the tumor progressed from pancreatic intraepithelial lesions to invasive PDAC, but was not related to chronic pancreatitis-associated inflammation or diabetes. In parallel the increased levels of branched-chain amino acids (BCAA) were observed. By contrast blood glutamine levels were stable in non-tumor bearing mice. These findings demonstrated that glutamine uptake is measurable both in vitro and in vivo. The higher in vitro avidity of PDAC cells corresponded to a lower blood glutamine level as soon as the tumor mass grew. The reduction in circulating glutamine represents a novel tool exploitable to implement other diagnostic or prognostic PDAC biomarkers.

Innovative superparamagnetic iron-oxide nanoparticles coated with silica and conjugated with linoleic acid: Effect on tumor cell growth and viability.

One of the goals for the development of more effective cancer therapies with reduced toxic side effects is the optimization of innovative treatments to selectively kill tumor cells. The use of nanovectors loaded with targeted therapeutic payloads is one of the most investigated strategies. In this paper superparamagnetic iron oxide nanoparticles (SPIONs) coated by a silica shell or uncoated, were functionalized with single-layer and bi-layer conjugated linoleic acid (CLA). Silica was used to protect the magnetic core from oxidation, improve the stability of SPIONs and tailor their surface reactivity. CLA was used as novel grafting biomolecule for its anti-tumor activity and to improve particle dispersibility. Mouse breast cancer 4T1 cells were treated with these different SPIONs. SPIONs functionalized with the highest quantity of CLA and coated with silica shell were the most dispersed. Cell viability was reduced by SPIONs functionalized with CLA in comparison with cells which were untreated or treated with SPIONs without CLA. As regards the types of SPIONs functionalized with CLA, the lowest viability was observed in cells treated with uncoated SPIONs with the highest quantity of CLA. In conclusion, the silica shell free SPIONs functionalized with the highest amount of CLA can be suggested as therapeutic carriers because they have the best dispersion and ability to decrease 4T1 cell viability.