Lactoferrin's anti-cancer properties. Safety, selectivity, and wide range of action

Despite recent advances in cancer therapy, current treatments, including radiotherapy, chemotherapy, and immunotherapy, although beneficial, present attendant side effects and long-term sequelae, usually more or less affecting quality of life of the patients. Indeed, except for most of the immunotherapeutic agents, the complete lack of selectivity between normal and cancer cells for radio- and chemotherapy can make them potential antagonists of the host anti-cancer self-defense over time. Recently, the use of nutraceuticals as natural compounds corroborating anti-cancer standard therapy is emerging as a promising tool for their relative abundance, bioavailability, safety, low-cost effectiveness, and immuno-compatibility with the host. In this review, we outlined the anti-cancer properties of Lactoferrin (Lf), an iron-binding glycoprotein of the innate immune defense. Lf shows high bioavailability after oral administration, high selectivity toward cancer cells, and a wide range of molecular targets controlling tumor proliferation, survival, migration, invasion, and metastasization. Of note, Lf is able to promote or inhibit cell proliferation and migration depending on whether it acts upon normal or cancerous cells, respectively. Importantly, Lf administration is highly tolerated and does not present significant adverse effects. Moreover, Lf can prevent development or inhibit cancer growth by boosting adaptive immune response. Finally, Lf was recently found to be an ideal carrier for chemotherapeutics, even for the treatment of brain tumors due to its ability to cross the blood-brain barrier, thus globally appearing as a promising tool for cancer prevention and treatment, especially in combination therapies

Mechanisms of lipid malabsorption in Cystic Fibrosis: the impact of essential fatty acids deficiency

Affiliation: CHU-Sainte-Justine, Université de MontréalTransport mechanisms, whereby alimentary lipids are digested and packaged into small emulsion particles that enter intestinal cells to be translocated to the plasma in the form of chylomicrons, are impaired in cystic fibrosis. The purpose of this paper is to focus on defects that are related to intraluminal and intracellular events in this life-limiting genetic disorder. Specific evidence is presented to highlight the relationship between fat malabsorption and essential fatty acid deficiency commonly found in patients with cystic fibrosis that are often related to the genotype. Given the interdependency of pulmonary disease, pancreatic insufficiency and nutritional status, greater attention should be paid to the optimal correction of fat malabsorption and essential fatty acid deficiency in order to improve the quality of life and extend the life span of patients with cystic fibrosis

Glycomic Analysis of Biomedically Important O-glycoconjugates

It has been established that all cells carry an array of glycans attached to proteins and lipids that are crucial in the interaction between cells and the surrounding matrix. Proteins are mainly glycosylated on asparagines (N-glycosylation) and serine or threonine residues (O-glycosylation). Compared to N-glycans, O-glycans offer a higher degree of structural ambiguity due to the existence of several types and cores. This is believed to contribute to the relative lack of knowledge on these molecules. Therefore, improvement to the current methodologies of structural studies is a prerequisite to complement the immense functional findings of O-glycoconjugates in biological systems. This thesis discusses the structural characterisation, regulation and biological roles of O-glycans. The overall aim was to optimise O-glycomic mass spectrometric analysis to help illuminate the phenotypic findings from our collaborators in three separate but related projects. The methodologies utilised involving MALDI-TOF/TOF-MS, GC-EI-MS, ESI-QTOF-MS and MALDI-QIT-TOF-MS. The first project investigated the effects of core 2 GlcNAc transferase (C2GnT) deficiency in mice. This enzyme exists in three isoforms which are expressed differently in different tissues. Analysis of the single knockout of each of these isoenzymes as well as the triple knockouts has allowed the investigation of their unique and overlapping functions. The outcomes of this study include characterisation of alterations of not just mucin-type O-glycans but also O-mannose glycan, which could be associated with several organ lesions and system failures. The second project focused on the gastric mucosa of mice with deficiency in α1,2-fucosyltranferase (FuT2). This enzyme plays an important role in decorating the mucosal mucins with ABH-blood group and Lewis antigens that are known to interact with various gut flora including the pathogen Helicobacter pylori. It has been shown that the binding of H. pylori via BabA adhesins was significantly impaired with the loss of H antigens and Lewis y on O-glycans. The third project investigated the regulation of mucin-type O-glycosylation. The protein Src has been recognised to play an essential role in the localisation of ppGalNAc transferases, the initiating enzyme of O-glycosylation, in the endoplasmic reticulum and Golgi apparatus. Therefore, it could be inferred that Src influences the regulation of protein O-glycosylation. The NIH3T3 and NBT-II cell lines with different levels of Src or different localisation of ppGalNAcT-2 have been analysed in order to identify the changes on the structures of O-glycans and the relative abundances of cores 1 and 2. Valuable information has been gathered which could lead to further investigative work to better understand the role of Src in the regulation of protein O-glycosylation

Diet and inflammation : the role of nitrate and conjugated linoleic acid

A diet rich in vegetables and unsaturated fatty acids is associated with a lower risk of major diseases including cardiovascular disease, type 2 diabetes and chronic inflammation. Yet, despite extensive research, the active component(s) responsible for these effects has not been pinpointed and studies with single nutrients have been largely unsuccessful. Recent research from our laboratory and elsewhere suggests that the inorganic anion nitrate (NO3-), especially abundant in green leafy vegetables, is converted in our bodies to nitrite (NO2-) and then further to nitric oxide (NO). The latter is a central signalling molecule with a number of beneficial effects in the cardiovascular- and gastrointestinal systems. Ingested nitrate is absorbed to the blood and mixed with nitrate from endogenous sources formed by NO synthases (NOS). Circulating nitrate is actively transported and accumulated in the salivary glands and excreted with saliva. Oral commensal bacteria play a surprisingly important role in nitrate bioactivation by reducing salivary nitrate to the more reactive nitrite anion. The nitrate-nitrite-NO pathway is now emerging as a significant source of NO, in addition to classical endogenous formation of this gas by NOS. A diet rich in vegetables and unsaturated fatty acids is associated with a lower risk of major diseases including cardiovascular disease, type 2 diabetes and chronic inflammation. Yet, despite extensive research, the active component(s) responsible for these effects has not been pinpointed and studies with single nutrients have been largely unsuccessful. Recent research from our laboratory and elsewhere suggests that the inorganic anion nitrate (NO3-), especially abundant in green leafy vegetables, is converted in our bodies to nitrite (NO2-) and then further to nitric oxide (NO). The latter is a central signalling molecule with a number of beneficial effects in the cardiovascular- and gastrointestinal systems. Ingested nitrate is absorbed to the blood and mixed with nitrate from endogenous sources formed by NO synthases (NOS). Circulating nitrate is actively transported and accumulated in the salivary glands and excreted with saliva. Oral commensal bacteria play a surprisingly important role in nitrate bioactivation by reducing salivary nitrate to the more reactive nitrite anion. The nitrate-nitrite-NO pathway is now emerging as a significant source of NO, in addition to classical endogenous formation of this gas by NOS. The results show that nitrite and dietary nitrate can reduce leukocyte recruitment during acute inflammation in the microcirculation. Dietary nitrate also prevented NSAID-provoked small intestinal inflammation in a process dependent on oral nitrate-reducing bacteria. Although strong anti-inflammatory effects were observed with dietary nitrate, the ability to clear an infection was not impaired. Dietary nitrate, nitrite and CLA were further demonstrated to alleviate inflammation in a mouse model of colitis. The protective effect seen with CLA involved upregulation of trefoil factor 3 (TFF3) expression through activation of peroxisome proliferator-activated receptor gamma (PPARγ) in the colon mucosa. Furthermore, dietary nitrite also had therapeutic effects in already established colonic inflammation, possibly mediated by maintaining the colonic mucus layer and promoting healing of colon epithelial cells. Finally, we demonstrate that the firmly adherent gastric mucus layer, normally present in conventional mice, was almost absent in germ free mice. In addition, a reduced gastric mucus layer was also observed in mice treated with broad spectrum antibiotics. While treatment with nitrate increased the mucus thickness further in conventional mice it had no effects in germ free mice, again demonstrating the essential role of oral bacteria in bioactivation of nitrate. Remarkably however, when the germ free mice were fed a low dose of nitrite, resembling what would normally be generated in saliva by bacteria, the gastric mucus thickness increased dramatically. This suggests that commensal oral bacteria modulate gastric homeostasis via physiological recycling of nitrate, originally derived from NOS. In conclusion, the studies in this thesis demonstrate that dietary nitrate, nitrite and CLA play a direct role in the regulation of inflammatory responses, both locally in the microcirculation and in the gastrointestinal tract. These results may have implications for future dietary recommendations in prevention and treatment of inflammatory disorders

Helicobacter pylori Infection Promotes Methylation and Silencing of Trefoil Factor 2, Leading to Gastric Tumor Development in Mice and Humans

Background & Aims Trefoil factors (TFFs) regulate mucosal repair and suppress tumor formation in the stomach. Tff1 deficiency results in gastric cancer, whereas Tff2 deficiency increases gastric inflammation. TFF2 expression is frequently lost in gastric neoplasms, but the nature of the silencing mechanism and associated impact on tumorigenesis have not been determined. Methods We investigated the epigenetic silencing of TFF2 in gastric biopsy specimens from individuals with Helicobacter pylori-positive gastritis, intestinal metaplasia, gastric cancer, and disease-free controls. TFF2 function and methylation were manipulated in gastric cancer cell lines. The effects of Tff2 deficiency on tumor growth were investigated in the gp130[superscript F/F] mouse model of gastric cancer. Results In human tissue samples, DNA methylation at the TFF2 promoter began at the time of H pylori infection and increased throughout gastric tumor progression. TFF2 methylation levels were inversely correlated with TFF2 messenger RNA levels and could be used to discriminate between disease-free controls, H pylori-infected, and tumor tissues. Genome demethylation restored TFF2 expression in gastric cancer cell lines, so TFF2 silencing requires methylation. In Tff2-deficient gp130[superscript F/F]/Tff2[superscript −/−] mice, proliferation of mucosal cells and release of T helper cell type-1 (Th-1) 1 cytokines increased, whereas expression of gastric tumor suppressor genes and Th-2 cytokines were reduced, compared with gp130[superscript F/F]controls. The fundus of gp130[superscript F/F]/Tff2[superscript −/−] mice displayed glandular atrophy and metaplasia, indicating accelerated preneoplasia. Experimental H pylori infection in wild-type mice reduced antral expression of Tff2 by increased promoter methylation. Conclusions TFF2 negatively regulates preneoplastic progression and subsequent tumor development in the stomach, a role that is subverted by promoter methylation during H pylori infection.National Health and Medical Research Council (Australia

Inactivation of pathogens on food and contact surfaces using ozone as a biocidal agent

This study focuses on the inactivation of a range of food borne pathogens using ozone as a biocidal agent. Experiments were carried out using Campylobacter jejuni, E. coli and Salmonella enteritidis in which population size effects and different treatment temperatures were investigate