The protective effect of 1400W against ischaemia and reperfusion injury is countered by transient medullary kidney endothelial dysregulation.

Renal ischaemia and reperfusion (I/R) is caused by a sudden temporary impairment of the blood flow. I/R is a prevalent cause of acute kidney injury. As nitric oxide generated by inducible nitric oxide synthase (iNOS) has detrimental effects during I/R, the pharmacological blockade of iNOS has been proposed as a potential strategy to prevent I/R injury. The aim of this study was to improve the understanding of 1400W (an iNOS inhibitor) on renal I/R as a pharmacological strategy against kidney disease. BALB/c mice received 30 min of bilateral ischaemia, followed by 48 h or 28 days of reperfusion. Vehicle or 1400W (10 mg/kg) was administered 30 min before inducing ischaemia. We found that after 48 h of reperfusion 1400W decreased the serum creatinine, blood urea nitrogen, neutrophil gelatinase-associated lipocalin and proliferating cell nuclear antigen 3 in the I/R animals. Unexpectedly, we observed mRNA upregulation of genes involved in kidney injury, cell-cycle arrest, inflammation, mesenchymal transition and endothelial activation in the renal medulla of sham animals treated with 1400W. We also explored if 1400W promoted chronic kidney dysfunction 28 days after I/R and did not find significant alterations in renal function, fibrosis, blood pressure or mortality. The results provide evidence that 1400W may have adverse effects in the renal medulla. Importantly, our data point to 1400W-induced endothelial dysfunction, establishing therapeutic limitations for its use. KEY POINTS: Acute kidney injury is a global health problem associated with high morbidity and mortality. The pharmacological blockade of inducible nitric oxide synthase (iNOS) has been proposed as a potential strategy to prevent AKI induced by ischaemia and reperfusion (I/R). Our main finding is that 1400W, a selective and irreversible iNOS inhibitor with low toxicity that is proposed as a therapeutic strategy to prevent kidney I/R injury, produces aberrant gene expression in the medulla associated to tissue injury, cell cycle arrest, inflammation, mesenchymal transition and endothelial activation. The negative effect of 1400W observed in the renal medulla at 48 h from drug administration, is transient as it did not translate into a chronic kidney disease condition.

The cluster [Re6Se8I6]3- penetrates biological membranes: drug-like properties for CNS tumor treatment and diagnosis.

Tumorigenic cell lines are more susceptible to [Re6Se8I6]3- cluster-induced death than normal cells, becoming a novel candidate for cancer treatment. Still, the feasibility of using this type of molecules in human patients remains unclear and further pharmacokinetics analysis is needed. Using coupled plasma optical emission spectroscopy, we determined the Re-cluster tissue content in injected mice, as a biodistribution measurement. Our results show that the Re-cluster successfully reaches different tissues, accumulating mainly in heart and liver. In order to dissect the mechanism underlying cluster biodistribution, we used three different experimental approaches. First, we evaluate the degree of lipophilicity by determining the octanol/water partition coefficient. The cluster mostly remained in the octanol fraction, with a coefficient of 1.86 ± 0.02, which indicates it could potentially cross cell membranes. Then, we measured the biological membrane penetration through a parallel artificial membrane permeability assays (PAMPA) assay. The Re-cluster crosses the artificial membrane, with a coefficient of 122 nm/s that is considered highly permeable. To evaluate a potential application of the Re-cluster in central nervous system (CNS) tumors, we analyzed the cluster's brain penetration by exposing cultured blood-brain-barrier (BBB) cells to increasing concentrations of the cluster. The Re-cluster effectively penetrates the BBB, reaching nearly 30% of the brain side after 24 h. Thus, our results indicate that the Re-cluster penetrates biological membranes reaching different target organs-most probably due to its lipophilic properties-becoming a promising anti-cancer drug with high potential for CNS cancer's diagnosis and treatment.

p73 participates in male germ cells apoptosis induced by etoposide.

Etoposide is a commonly used drug in testicular cancer chemotherapy. However, the molecular pathways that activate germ cell apoptosis in response to etoposide are poorly understood. The aim of this study was to evaluate the participation of p73, a member of the p53 family, in apoptosis induced by etoposide in male germ cells. First, we used GC2-spc cells-a male germ cell model-to evaluate apoptotic signaling after treatment of etoposide. We found an important increase in p73 protein levels, along with the c-Abl kinase, its physiological activator, in response to etoposide. This increase was accompanied by a decrease in cell viability and activation of caspase-3. Pifithrin (PFT) treatment prevented p73 increase and apoptosis induced by etoposide. Also, the in vitro knockdown of p73 or p53 by shRNA, significantly prevented the decrease in cell viability after etoposide treatment. In an in vivo model-21-day-old rat testes-we observed an up-regulation of the protein levels of p73 and phosphorylated p73-at c-Abl site Tyr99-in response to the etoposide injection. STI571 (a pharmacological inhibitor of c-Abl) or PFT co-injection prevented etoposide-induced up-regulation of phospho-p73 and pro-apoptotic TAp73 isoform levels. Moreover, caspases-3, -8, -9 activation and germ cell death induced by etoposide were significantly decreased by these drugs. These results support the notion that the c-Abl/p73 pathway is activated in germ cells after etoposide treatment, triggering apoptosis, possibly assisting p53.