Could be FOXO3a, miR-96-5p and miR-182-5p useful for Brazilian women with luminal A and triple negative breast cancers prognosis and target therapy?

FOXO3a dysregulation is frequently implicated in tumorigenesis, and its inhibition can occur by several molecular mechanisms. Among these, post-transcriptional suppression by miRNAs has been associated with various cancers initiation. Here, we assessed the expression profiles of the most relevant miRNAs for breast tumorigenesis, using Luminal A (LA) and Triple-Negative (TN) breast cancer from Brazilian patients, by the quantitative real time-PCR method. Their potential prognostic role for the patients was also evaluated. We identified the miRNAs miR-96-5p and miR-182-5p, de-scribed as negative regulators of FOXO3A, with differential expression both in LA and TN tumors when compared to normal tissue. The miR-96-5p and miR-182-5p miRNAs were upregulated in LA (7.82 times, p < 0.005; 6.12 times, p < 0.005, respectively) and TN breast cancer samples (9.42 times, p < 0.0001; 8.51 times, p < 0.0001) compared to normal tissues. The samples with higher miR-96-5p and miR-182-5p expression (FR ≥ 4) were submitted for FOXO3a immunostaining. Reduced protein detection was observed in all of the tumors compared to normal tissues. The most prominent miRNA expression and FOXO3a protein suppression were observed in TN samples (p < 0.001), indicating the relevant role of these molecules in this tumor biology and clinical behavior. Our results corroborate the literature regarding to the relevance of FOXO3a in the breast cancer, and they open new perspectives for alternative target therapy options for Brazilian patients expressing both FOXO3a and its regulatory miRNAs.

Involvement of oxidative stress in the hepatotoxicity induced by aromatic antiepileptic drugs.

The use of the classic aromatic antiepileptic drugs (AAEDs) has recently been expanded to a broad spectrum of psychiatric and neurological disorders. However, the clinical use of these drugs is limited by several adverse effects, mainly idiosyncratic hepatotoxicity. AAED-induced hepatotoxicity has been attributed to a defective detoxification by the epoxide hydrolase and accumulation of arene oxides. The underlying mechanism has been proposed as immune-mediated, but direct toxicity has also been suggested. In general, idiosyncratic drug-induced hepatotoxicity may be mediated, at least in part, by oxidative stress. On the other hand, the oxidative stress induced by the AAED metabolites has not been demonstrated yet. Therefore, in the present study we have evaluated the induction of oxidative stress by three classical AAEDs: carbamazepine, phenytoin and phenobarbital as well as by their metabolites. The toxic effects of the metabolites were evaluated by incubating the drug with rat liver microsomes. The AAED-induced oxidative stress was demonstrated by the increased malondialdehyde levels, oxidation of cardiolipin; oxidation of sulfhydryl proteins and alteration of the cellular redox status. Results suggest that the hepatotoxicity associated with AAED might be mediated by the oxidative stress induced by the drugs metabolites.

Aromatic antiepileptic drugs and mitochondrial toxicity: effects on mitochondria isolated from rat liver.

Idiosyncratic hepatotoxicity is a well-known complication associated with aromatic antiepileptic drugs (AAED), and it has been suggested to occur due to the accumulation of toxic arene oxide metabolites. Although there is clear evidence of the participation of an immune process, a direct toxic effect involving mitochondria dysfunction is also possible. The effects of AAED on mitochondrial function have not been studied yet. Therefore, we investigated, in vitro, the cytotoxic mechanism of carbamazepine (CB), phenytoin (PT) and phenobarbital (PB), unaltered and bioactivated, in the hepatic mitochondrial function. The murine hepatic microsomal system was used to produce the anticonvulsant metabolites. All the bioactivated drugs (CB-B, PB-B, PT-B) affected mitochondrial function causing decrease in state three respiration, RCR, ATP synthesis and membrane potential, increase in state four respiration as well as impairment of Ca2+ uptake/release and inhibition of calcium-induced swelling. As an unaltered drug, only PB, was able to affect mitochondrial respiration (except state four respiration) ATP synthesis and membrane potential; however, Ca2+ uptake/release as well as swelling induction were not affected. The potential to induce mitochondrial dysfunction was PT-B>PB-B>CB-B>PB. Results suggest the involvement of mitochondrial toxicity in the pathogenesis of AAED-induced hepatotoxicity.

Antiepileptogenic properties of phenobarbital: behavior and neurochemical analysis.

Chronic in vivo models of epilepsy provide a suitable strategy for quantifying epileptogenesis, as well as investigating neurochemical changes associated with neuronal plasticity that leads to seizuring conditions. The aim of this paper was to investigate antiepileptogenic properties of phenobarbital, focusing on the neurochemical changes associated with repeated seizures induced by low convulsive dose of pentylenetetrazol (PTZ) (60 mg/kg, sc) in mice. Phenobarbital (10 and 30 mg/kg, ip) significantly diminished the severity of seizures induced by PTZ. Repeated PTZ administration was associated with an increase in [3H]glutamate binding (B(max) 196.6+/-10.2 pmol/mgxcontrol B(max) 137.7+/-17.0 pmol/mg). Regarding NMDA receptors, repeated PTZ administration was likewise associated with an increase in [3H]MK-801 binding (0.55+/-0.02 pmol/mgxcontrol 0.32+/-0.01 pmol/mg). In addition, phenobarbital (10 mg/kg) prevented the increase in [3H]glutamate binding (B(max) 133.7+/-11.4 pmol/mg), as well as in [3H]MK-801 binding (phenobarbital 10 and 30 mg/kg, 0.33+/-0.01 and 0.34+/-0.01 pmol/mg, respectively). This study reveals an interesting capability of phenobarbital in interfering with the establishment of both the behavioral expression and associated neurochemical changes induced by the repeated administration of low convulsive dose of PTZ, which may be important in the context of preventing epileptogenesis.

[Experimental cholelithiasis in animals]. / Colelitiasis experimental en animales.

This paper reviews the most relevant animal-based knowledge in gallstone formation, and its contribution to our improved understanding of the human illness. The importance of diet, age, sex and hormones has been proved in both animals and humans. Nevertheless, there are clear cut differences among species which make general conclusions hard to obtain. Although there is no ideal experimental animal, primates and hamsters seem to be close. Guinea-pigs, rats, mice, rabbits and dogs have been useful in providing key information in certain areas. The paramount importance of alterations in the lipidic composition of bile in lithogenesis is supported by experimental research in animals and has been ratified in humans. Diet is the main mechanism for experimental gallstone formation in animals. Observation of drug-induced lithogenesis in animals has made investigators aware of such phenomenon in humans.

[Hepatinecrosis caused by furosemide. Special lesions of various species?]. / Hepatonecrosis por furosemida. Lesión privativa de algunas especies?

Furosemide is a wellknown hepatotoxic agent in rodents. Toxicity is result of the production of a catabolite by action of microsomal enzymes. The goal of this study was to demonstrate differences in toxicity between two rodents species: rat and hamster. Animals received 400 mg/k/i.p. of furosemide, with or without pretreatment with phenobarbital as enzymatic inducer. Adequates controls were used. Microscopic findings were different in both groups. Rats treated with furosemide plus phenobarbital, exhibited extensive mediozonal necrosis; when those without pretreatment, showed less extensive necrosis of liver cells, erratic in distribution. In contrast, it was a lack of necrosis in hamsters' livers, showing only unremarkable changes.