Indomethacin Disrupts Autophagic Flux by Inducing Lysosomal Dysfunction in Gastric Cancer Cells and Increases Their Sensitivity to Cytotoxic Drugs.

NSAIDs inhibit tumorigenesis in gastrointestinal tissues and have been proposed as coadjuvant agents to chemotherapy. The ability of cancer epithelial cells to adapt to the tumour environment and to resist cytotoxic agents seems to depend on rescue mechanisms such as autophagy. In the present study we aimed to determine whether an NSAID with sensitizing properties such as indomethacin modulates autophagy in gastric cancer epithelial cells. We observed that indomethacin causes lysosomal dysfunction in AGS cells and promotes the accumulation of autophagy substrates without altering mTOR activity. Indomethacin enhanced the inhibitory effects of the lysosomotropic agent chloroquine on lysosome activity and autophagy, but lacked any effect when both functions were maximally reduced with another lysosome inhibitor (bafilomycin B1). Indomethacin, alone and in combination with chloroquine, also hindered the autophagic flux stimulated by the antineoplastic drug oxaliplatin and enhanced its toxic effect, increasing the rate of apoptosis/necrosis and undermining cell viability. In summary, our results indicate that indomethacin disrupts autophagic flux by disturbing the normal functioning of lysosomes and, by doing so, increases the sensitivity of gastric cancer cells to cytotoxic agents, an effect that could be used to overcome cancer cell resistance to antineoplastic regimes.

Aspirin-induced gastrointestinal damage is associated with an inhibition of epithelial cell autophagy.

BACKGROUND: Aspirin (ASA) causes gastrotoxicity by hampering the epithelial defense against luminal contents through cyclooxygenase inhibition. Since cell survival in tough conditions may depend on rescue mechanisms like autophagy, we analyzed whether epithelial cells rely on this process to defend themselves from aspirin's damaging action. METHODS: Rats received a single dose of ASA (150 mg/kg, p.o.) with or without pretreatment with the autophagy inhibitor 3-methyladenine, and gastric injury and epithelial autophagy were evaluated 3 h later. The effects of ASA on cell viability and autophagy were also evaluated in gastric epithelial AGS cells. RESULTS: Basal autophagy in the gastric mucosa was inhibited by ASA as demonstrated by increased levels of p62 and ubiquitinated proteins and total LC3 and a reduced LC3-II/LC3-I ratio. Similarly, ASA increased p62 and decreased LC3-II accumulation and the number of EmGFP/LC3B puncta in AGS cells. ASA activated the PI3K/Akt-GSK3-mTOR pathway, which phosphorylates ULK1 to prevent autophagy initiation, changes that were inhibited by the PI3K-inhibitor wortmannin. Autophagy inhibition seems to enhance the vulnerability of gastric epithelial cells as a combination of ASA with 3-methyladenine exacerbated rat gastric damage and AGS cell apoptosis. CONCLUSIONS: Our data highlight the importance of autophagy in the gastric mucosa as a protective mechanism when the epithelium is injured. In the stomach, aspirin induces mucosal damage and reduces autophagy, thus, eliminating a protective mechanism that epithelial cells could use to escape death. We hypothesize that the combination of aspirin with drugs that activate autophagy could protect against gastric damage.

Cystatin C, cardiometabolic risk, and body composition in severely obese children.

The aim of this study was to assess the relationship between cystatin C (CysC), cardiometabolic risk factors (CMRFs), and body composition in severely obese children. We evaluated 117 children aged 7-14 years old. Seventy-nine of these were severely obese (body mass index z-score ranging from 2.1 to 8.4), and 38 were children with normal nutrition state. CysC was determined by immunonephelometry. CMRFs (glucose, insulin, high-density lipoprotein cholesterol, triglycerides, homocysteine, uric acid, alanine aminotransferase, and high-sensitivity C-reactive protein) were measured by standard biochemical methods. Blood pressure was evaluated at the clinical examination. Renal function was estimated using the glomerular filtration rate (eGFR) based upon creatinine levels, and body weight (Léger formula). Body composition was assessed by segmental bioelectrical impedance. Obese children at the highest tertile of CysC values were characterized by their aggregation of CMRFs. CysC concentration was associated with insulin resistance, alanine aminotransferase, uric acid, and homocysteine after adjusting for age, gender, and eGFR. CysC values were also correlated with the fat-free mass and specifically with skeletal muscle mass. CysC levels were correlated with CMRFs factors independently of renal function, and affected by skeletal muscle mass in severely obese children, although they are less influenced by this than is creatinine.