Na/K-ATPase as a target for anticancer drugs: studies with perillyl alcohol.

BACKGROUND: Na/K-ATPase (NKA) is inhibited by perillyl alcohol (POH), a monoterpene used in the treatment of tumors, including brain tumors. The NKA α1 subunit is known to be superexpressed in glioblastoma cells (GBM). This isoform is embedded in caveolar structures and is probably responsible for the signaling properties of NKA during apoptosis. In this work, we showed that POH acts in signaling cascades associated with NKA that control cell proliferation and/or cellular death. METHODS: NKA activity was measured by the amount of non-radioactive Rb(+) incorporation into cultured GBM cell lines (U87 and U251) and non-tumor cells (mouse astrocytes and VERO cells). Cell viability was measured by lactate dehydrogenase levels in the supernatants of POH-treated cells. Activated c-Jun N-terminal Kinase (JNK) and p38 were assessed by western blotting. Apoptosis was detected by flow cytometry and immunocytochemistry, and the release of interleukins was measured by ELISA. RESULTS: All four cell types tested showed a similar sensitivity for POH. Perillic acid (PA), the main metabolite of POH, did not show any effect on these cells. Though the cell viability decreased in a dose-dependent manner when cells were treated with POH, the maximum cytotoxic effect of PA obtained was 30% at 4 mM. 1.5 mM POH activated p38 in U87 cells and JNK in both U87 and U251 cells as well as mouse astrocytes. Dasatinib (an inhibitor of the Src kinase family) and methyl ß-cyclodextrin (which promotes cholesterol depletion in cell membranes) reduced the POH-induced activation of JNK1/2 in U87 cells, indicating that the NKA-Src complex participates in this mechanism. Inhibition of JNK1/2 by the JNK inhibitor V reduced the apoptosis of GBM cells that resulted from POH administration, indicating the involvement of JNK1/2 in programmed cell death. 1.5 mM POH increased the production of interleukin IL-8 in the U251 cell supernatant, which may indicate a possible strategy by which cells avoid the cytotoxic effects of POH. CONCLUSIONS: A signaling mechanism mediated by NKA may have an important role in the anti-tumor action of POH in GBM cells.

Oleic acid induces lung injury in mice through activation of the ERK pathway.

Oleic acid (OA) can induce acute lung injury in experimental models. In the present work, we used intratracheal OA injection to show augmented oedema formation, cell migration and activation, lipid mediator, and cytokine productions in the bronchoalveolar fluids of Swiss Webster mice. We also demonstrated that OA-induced pulmonary injury is dependent on ERK1/2 activation, since U0126, an inhibitor of ERK1/2 phosphorylation, blocked neutrophil migration, oedema, and lipid body formation as well as IL-6, but not IL-1ß production. Using a mice strain carrying a null mutation for the TLR4 receptor, we proved that increased inflammatory parameters after OA challenges were not due to the activation of the TLR4 receptor. With OA being a Na/K-ATPase inhibitor, we suggest the possible involvement of this enzyme as an OA target triggering lung inflammation.

Inhibition of mammal Na(+)K(+)-ATPase by diterpenes extracted from the Brazilian brown alga Dictyota cervicornis.

The dolastane diterpenes 4-acetoxy-9,14-dihydroxydolast-1(15),7-diene (1) and 4,7-diacetoxy-14-hydroxydolast-1(15),8-diene (2) were isolated from specimens of the alga Dictyota cervicornis collected from the Rio de Janeiro coast, Brazil. Chemical structures of the diterpenes were assigned by 1D and 2D NMR spectral data for the first time. Both substances inhibited Na(+)K(+)-ATPase preparations from guinea-pig brain or kidney, with the same inhibitory potency towards enzyme isoforms. The maximal inhibition obtained for 1 was 40% at a concentration of 0.5 mm in the incubation mixture, while it reached 80% for compound 2 at this concentration. Ouabain insensitive ATPases were inhibited by 1, but not by 2. Data comparing the inhibitory potency of these compounds with that of ouabain and oleic acid suggest a higher degree of selectivity of 2 towards the Na(+)K(+)-pump. Cardiac glycosides such as ouabain are used classically in the treatment of heart failure, but alterations of Na(+)K(+)-pump activity are also involved in several other diseases. Therefore, the study of compounds interfering with this pump activity is gaining further importance.

[Pesticide pollution in water systems in a small rural community in Southeast Brazil]. / Análise da contaminação dos sistemas hídricos por agrotóxicos numa pequena comunidade rural do Sudeste do Brasil.

Recent advances in analytical techniques allow identifying pesticide pollution in water systems. In small rural communities, the negative effects of pesticide pollution can be aggravated by the lack of infrastructure and adverse socioeconomic conditions. This study investigated pesticide pollution in potential water supply sources in a tomato growing area in Paty do Alferes, Rio de Janeiro State, Brazil. The study selected 27 points where five monthly samples were collected. Pesticide pollution was determined by analyzing acetyl-cholinesterase inhibition. In 19 of the 27 sample points, some pesticide pollution was detected, and in two points the pesticide pollution was above the permitted limits. The results thus proved the incidence of pesticide pollution in water sources in Paty do Alferes that could jeopardize the local population's health.

Análise da contaminação dos sistemas hídricos por agrotóxicos numa pequena comunidade rural do Sudeste do Brasil / Pesticide pollution in water systems in a small rural community in Southeast Brazil

Só recentemente, com a evolução das técnicas analíticas foi possível a detecção de contaminação por agrotóxicos nos sistemas hídricos. Em pequenas comunidades rurais, os efeitos negativos à saúde pública de uma contaminação dos sistemas hídricos seriam agravados pela falta de infra-estrutura e de condições sócio-econômicas. O objetivo deste estudo foi analisar essa possível contaminação por agrotóxicos nos sistemas hídricos superficiais e subterrâneos utilizados para consumo humano direto na região da cultura do tomate no Município de Paty do Alferes, Rio de Janeiro, Brasil. Para isso, este estudo selecionou 27 pontos de coleta, onde foram feitas cinco coletas mensais, perfazendo um total de 135 amostras. A contaminação de sistemas hídricos por organofosforados e carbamatos foi determinada pela análise da inibição da atividade da enzima acetilcolinesterase. O resultado encontrado foi que em 19 dos 27 pontos selecionados houve contaminação detectável, sendo que em duas ocasiões essas contaminações ultrapassaram o permitido pela legislação. Com isso, comprovou-se a contaminação dos sistemas hídricos na região de Paty do Alferes, o que colocaria a saúde da população local em risco.

Recent advances in analytical techniques allow identifying pesticide pollution in water systems. In small rural communities, the negative effects of pesticide pollution can be aggravated by the lack of infrastructure and adverse socioeconomic conditions. This study investigated pesticide pollution in potential water supply sources in a tomato growing area in Paty do Alferes, Rio de Janeiro State, Brazil. The study selected 27 points where five monthly samples were collected. Pesticide pollution was determined by analyzing acetyl-cholinesterase inhibition. In 19 of the 27 sample points, some pesticide pollution was detected, and in two points the pesticide pollution was above the permitted limits. The results thus proved the incidence of pesticide pollution in water sources in Paty do Alferes that could jeopardize the local population's health.

Efeito da lavagem e cocção em batatas contaminadas por pesticidas organofosforados e carbamatos / Effect of the washing and cooking in potatos contaminated by organophosphate pesticides and carbamates

Os pesticidas organosfosfados e carbamatos são utilizados em cultura de frutas e hortaliças e são substâncias muito tóxicas para o ambiente e o organismos humano e ainda podem causar distúrbios neurológicos. O estudo teve por objetivo avaliar a eficácia da lavagem em água corrente e da cocção por fervura para remover resíduos de pesticidas na casca e na polpa de batatas. Foram escolhidas batatas cultivadas por processo tradicional e orgânico compradas em organizações comerciais na cidade do Rio de Janeiro. Foram analisadas doze amostras: oito de supermercados, duas de hortifruti, uma de feira livre e uma de mercearia. Cada amostra representativa analisada pesou 2 kg. O método aplicado foi o método enzimático desenvolvido no Laboratório de Biologia CeluLar – ENZITOX;UERJ. Os resultados mostraram que a amostra de batatas originada da mercearia tinha a maior concentração em resíduo de carbamato e que o cozimento por fervura é um processo muito importante para reduzir a concentração dessas substâncias tóxicas.