ALDH1A3 is epigenetically regulated during melanocyte transformation and is a target for melanoma treatment.

Despite the promising targeted and immune-based interventions in melanoma treatment, long-lasting responses are limited. Melanoma cells present an aberrant redox state that leads to the production of toxic aldehydes that must be converted into less reactive molecules. Targeting the detoxification machinery constitutes a novel therapeutic avenue for melanoma. Here, using 56 cell lines representing nine different tumor types, we demonstrate that melanoma cells exhibit a strong correlation between reactive oxygen species amounts and aldehyde dehydrogenase 1 (ALDH1) activity. We found that ALDH1A3 is upregulated by epigenetic mechanisms in melanoma cells compared with normal melanocytes. Furthermore, it is highly expressed in a large percentage of human nevi and melanomas during melanocyte transformation, which is consistent with the data from the TCGA, CCLE and protein atlas databases. Melanoma treatment with the novel irreversible isoform-specific ALDH1 inhibitor [4-dimethylamino-4-methyl-pent-2-ynthioic acid-S methylester] di-methyl-ampal-thio-ester (DIMATE) or depletion of ALDH1A1 and/or ALDH1A3, promoted the accumulation of apoptogenic aldehydes leading to apoptosis and tumor growth inhibition in immunocompetent, immunosuppressed and patient-derived xenograft mouse models. Interestingly, DIMATE also targeted the slow cycling label-retaining tumor cell population containing the tumorigenic and chemoresistant cells. Our findings suggest that aldehyde detoxification is relevant metabolic mechanism in melanoma cells, which can be used as a novel approach for melanoma treatment.

Aldehyde dehydrogenases inhibition eradicates leukemia stem cells while sparing normal progenitors.

The vast majority of patients with acute myeloid leukemia (AML) achieve complete remission (CR) after standard induction chemotherapy. However, the majority subsequently relapse and die of the disease. A leukemia stem cell (LSC) paradigm has been invoked to explain this failure of CR to reliably translate into cure. Indeed, LSCs are highly enriched in CD34+CD38- leukemic cells that exhibit positive aldehyde dehydrogenase activity (ALDH+) on flow cytometry, these LSCs are resistant to currently existing treatments in AML such as cytarabine and anthracycline that, at the cost of great toxicity on normal cells, are highly active against the leukemic bulk, but spare the LSCs responsible for relapse. To try to combat the LSC population selectively, a well-characterized ALDH inhibitor by the trivial name of dimethyl ampal thiolester (DIMATE) was assessed on sorted CD34+CD38- subpopulations from AML patients and healthy patients. ALDH activity and cell viability were monitored by flow cytometry. From enzyme kinetic studies DIMATE is an active enzyme-dependent, competitive, irreversible inhibitor of ALDH1. On cells in culture, DIMATE is a powerful inhibitor of ALDHs 1 and 3, has a major cytotoxic activity on human AML cell lines. Moreover, DIMATE is highly active against leukemic populations enriched in LSCs, but, unlike conventional chemotherapy, DIMATE is not toxic for healthy hematopoietic stem cells which retained, after treatment, their self-renewing and multi-lineage differentiation capacity in immunodeficient mice, xenografted with human leukemic cells. DIMATE eradicates specifically human AML cells and spares healthy mouse hematologic cells.

α,ß-Acetylenic amino thiolester inhibitors of aldehyde dehydrogenases 1&3: suppressors of apoptogenic aldehyde oxidation and activators of apoptosis.

The aim of this minireview is to recapitulate the evidence in the literature supporting a role for the aldehyde dehydrogenases (ALDH1, ALDH2 and ALDH3) in controlling the levels of 3 endogenous apoptogenic aldehydes: methional, malondialdehyde (MDA) and 4-hydroxynonenal (HNE). All 3 aldehydes are formed during the metabolism of cellular constituents. Methional is derived from the oxidative decarboxylation of 4-methylthio-2-oxobutanoate coming from the methionine salvage pathway. MDA arises from the peroxidation of lipids and also from methional subjected to attack by reactive oxygen species (ROS). HNE is formed primarily from lipid peroxidation by ROS attack. One major origin of ROS is the dysfunctional electron transport chain in the mitochondria of cancer cells. As bifunctional electrophilic compounds, HNE forms adducts with cellular nucleophiles e.g. GSH, whilst MDA acts as a potent DNA/protein cross-linking agent in vitro and in vivo. Cancer cells protect themselves from the apoptogenic effect of these aldehydes by the ALDHs that oxidize them to their non-apoptogenic carboxylic acids. Indeed, the over-expression of ALDH3 protects cells from HNE-induced apoptosis. The inhibition of ALDH1 allows methional to reach its apoptogenic threshold in BAF3bcl2 that were resistant to methional-inducible apoptosis. One member of the α,ß-acetylenic N-substituted aminothiol ester family is an "active-enzyme-dependent", competitive, irreversible inhibitor of ALDH1 in vitro, an inhibitor of ALDH1 and ALDH3 in rat and human cancer cells in culture, an irreversible apoptogen on chemoresistant bcl2(+++) murine lymphoid and human epithelial cancer cells but a reversible cytostatic compound on human prostate epithelial normal cells in culture.

Synergetic bitherapy in mice with xenografts of human prostate cancer using a methional mimic (METLICO) and an aldehyde dehydrogenase 3 inhibitor (MATE): systemic intraperitoneal (IP) and targeted intra-tumoral (IT) administration.

An intraperitoneal (IP) monotherapy in nu/nu mice with subcutaneous xenografts of a human prostate epithelial cancer cell line:DU145 was undertaken with an aldehyde dehydrogenase 3 inhibitor MATE, that is a potent apoptogen on (DU145) in culture but not on their human prostate epithelial normal counterparts [13] . Tumour growth was slowed down but treatment had to be done 5days/week. To try to potentiate the action of MATE in vivo, a bitherapy was undertaken based on the synergetic apoptotic effect that had been observed previously in culture on DU145 treated with a methional mimic METLICO and DIMATE, an inhibitor of ALDH1 and ALDH3 [19]. The bitherapy with METLICO/MATE administered IP was as effective as the monotherapy with MATE alone by IP, but at a 2-fold lower dose of MATE and at a dose of METLICO that had no growth-inhibitory effect as a monotherapy . Hence there was definite synergism with bitherapy. To try to increase the efficacy of bitherapy, it was administered by the intra-tumoral (IT) route using the recently developed 20-bars-pressurized microinjection system from CERMA [16, 17]. IT administration of the bitherapy was indeed more effective than that by IP as regards tumour volumes are concerned. Histopathological analysis of IT-treated tumours confirmed that there were many necrotized zones but intact cells were still present. Approaches for treating a wider zone of tumour tissue by IT-bitherapy are discussed.

The effect of a novel irreversible inhibitor of aldehyde dehydrogenases 1 and 3 on tumour cell growth and death.

Aldehyde dehydrogenases (ALDHs) are a family of several isoenzymes expressed in various tissues and in all subcellular fractions. In some tumours, there is an increase of ALDH activity, especially that of class 1 and 3. The increase in the activity of these isoenzymes is correlated with cell growth and drug resistance shown by these cells. It has been observed that hepatoma cells expressing low ALDH3 activity are more susceptible to growth inhibition by low concentration of lipid peroxidation products than hepatoma cells expressing high ALDH3 activity. The products of lipid peroxidation are good substrates for ALDH, but when their intracellular levels are increased in hepatoma cells treated repeatedly with prooxidants, they inhibit ALDH3 and bring about growth inhibition or cell death. As a follow up to the work previously reported on S-methyl 4-amino-4-methylpent-2-ynethioate, a synthetic suicide inhibitor of ALDH1, which induced bcl2 overexpressing cells into apoptosis and exhibited an ED50 of 400 microM, a novel broad spectrum inhibitor of ALDH1 and ALDH3 was synthesised. This new compound (ATEM) is a suicide inhibitor of ALDH1, an irreversible inhibitor of ALDH3 and exhibits an ED50 of 10-25 microM on rat cultured hepatoma cells. Four hours after treatment with 25 microM ATEM, ALDH activity using benzaldehyde or propionaldehyde in hepatoma cells was decreased by 40% and cell number by 15% compared with controls. As cell growth did not resume when the inhibitor was removed from the culture medium, it suggested strongly that ALDHs play a pivotal role in mediating cell death.

Dose-dependent activation and block by bisG10, a K+ channel blocker, of mouse and frog skeletal muscle KATP channels.

The effects of a K+ channel blocker, bisG10, were examined on ATP-sensitive K+ (KATP) channels in membrane patches excised from mammalian and amphibian skeletal muscle fibres using the patch-clamp technique. At micromolar concentrations, bisG10, added on the intracellular side, induced a strong, reversible, flickery block of KATP channels. BisG10, added on the extracellular side, was about 100-fold less potent at inhibiting channel activity. At 10 nM, intracellular bisG10 increased KATP channel activity. This activation was independent of the presence of internal ATP or Mg2+. The inhibitory effect of bisG10 most likely arose from open-channel block whereas activation could result from more complex, indirect interactions.

Methional derived from 4-methylthio-2-oxobutanoate is a cellular mediator of apoptosis in BAF3 lymphoid cells.

4-Methylthio-2-oxobutanoic acid is the direct precursor of methional, which is a potent inducer of apoptosis in a BAF3 murine lymphoid cell line which is interleukin-3 (IL3)-dependent. Cultures treated for 8 h with methional in the presence of IL3 show extensive DNA double-strand breaks on flow cytometric analysis, increases in DNA fragmentation as measured by the amount of non-sedimentable DNA present in the 30,000 g supernatant of cell lysates and the typical laddering pattern of multiples of 180 bp seen upon agarose gel electrophoresis. No such features of apoptosis were found in cells treated with 4-methylthio 2-oxobutanoic acid or propanal, suggesting that the simultaneous presence of the methylthio group on the propanal moiety is essential for apoptosis to take place. Methional is further metabolized in cells by two reactions: oxidation via aldehyde dehydrogenase to (methylthio)propionic acid or beta-hydroxylation to malondialdehyde. The formation of malondialdehyde from methional in vitro by chemical hydroxylation under the conditions of the Fenton reaction provides a mechanism for the beta-hydroxylation which takes place in vivo. During apoptosis induced by IL3 deprivation, the ratio of 2,4-DNPH MDA to 2,4-DNPH methional is 0.94 in cells in IL3- medium compared with 0.54 in cells in IL3+ medium. These results support a role of cellular methional and malondialdehyde in apoptosis.

Attitudes of registered nurses toward euthanasia.

We sought to identify variables that contribute to euthanasia attitude and behavior, including demographics, death fears, experience with death, attitudes toward patient autonomy, and level of moral development. Subjects were 137 registered nurses from the southeastern United States representing 13 clinical nursing areas. Principal components analysis identified four factors that together explained 62.9% of total variance. These factors were belief in afterlife, nursing experience, liberal or conservative political view, and personal values. Variables identified through factor analysis were entered into regression analyses. These analyses showed that increased religious belief, years of nursing experience, and propensity to view death as an end of existence predicted opposition to euthanasia. Predictors for euthanasia support included a liberal political view, more experience with dying patients, and the belief that patients should have a personal responsibility for their own health-care decisions.

Response to Kirton.

Further comment and analyses of data from 103 alcoholics indicate less internal consistency in alcoholics' responding than in normals, no tendency for innovative alcoholics to engage in more hostile/aggressive behaviors than adaptor alcoholics, and a likelihood that more than three factors for alcoholics would be required to account for variance comparable to that for nonalcoholic persons.

A factor analysis of the Kirton Adaption-Innovation Inventory using an alcoholic population.

The present study reports a factor analysis of the Kirton Adaption-Innovation Inventory using 103 alcoholic men. Kirton in 1976 and we in an unpublished work in 1986 noted identical factor structures when responses from nonalcoholic populations to the inventory were factor analyzed. Recent reviews regarding personality characteristics of alcoholics suggest characteristics similar to the adaption-innovation concepts of Kirton. This factor analysis for an alcoholic sample supports the validity of the inventory as a measure of problem-solving style of alcoholics.

Relationship of field dependence/independence to adaption-innovation in alcoholics.

Using alcoholics as subjects, the present study attempted a replication of Kirton's 1978 study in which he demonstrated a relationship between his adaption-innovation theory and Witkin's concept of field dependence/independence. Correlations obtained in the present study paralleled those of Kirton. As a group, alcoholics tended to be field-dependent in orientation. Innovators were less field-dependent than adaptors and "average" individuals. It was suggested that the varied characteristics of alcoholics should be considered when planning therapeutic strategies.

[Transfusional malaria. Apropros of a case in Limousin]. / Paludisme post-transfusionnel. A propos d'un cas en limousin.

Transfusional malaria is a disease in continual increase because of the greater number of international journeys and because of the insufficient prophylaxis at the present time. The authors report a new case which occurred in Limoges due to Plasmodium falciparum. The blood-donor was cambodgian and specific immunological tests were positive on this serum. Any fever, without evident cause, happening after blood or blood-derivative transfusion must suggest transfusional malaria. This diagnosis must be quickly confirmed by parasite detection in the blood and a good and efficient treatment will be easy. Maybe soon a culture of human Plasmodium in human red cells will make possible an efficient prophylaxis using a cheap fluorescent antibody test.

Sex differences in self-perceptions as students of excellence and academic performance.

Differences between the sexes in self-ratings on 37 characteristics of a quality student, changes in their perceptions over a semester, and academic performances were analyzed for 172 male and 281 females. The characteristics were collapsed into five groups reflecting learning in class, study habits and attitudes, peer relationships, student-instructor relationships, and physical and emotional needs. Trend analyses showed significant differences (a) between the sexes on three grouped characteristics: learning in class, study habits and attitudes, and peer relationships (with females reporting higher ratings), (b) among the three self-rating sessions(reflecting upward trends) on all grouped characteristics, and (c) on one interaction, student-instructor relationships. Analysis of variance showed that the females obtained significantly higher grades than did the males.