Reversion of apoptotic resistance of TP53-mutated Burkitt lymphoma B-cells to spindle poisons by exogenous activation of JNK and p38 MAP kinases.

Defects in apoptosis are frequently the cause of cancer emergence, as well as cellular resistance to chemotherapy. These phenotypes may be due to mutations of the tumor suppressor TP53 gene. In this study, we examined the effect of various mitotic spindle poisons, including the new isocombretastatin derivative isoNH2CA-4 (a tubulin-destabilizing molecule, considered to bind to the colchicine site by analogy with combretastatin A-4), on BL (Burkitt lymphoma) cells. We found that resistance to spindle poison-induced apoptosis could be reverted in tumor protein p53 (TP53)-mutated cells by EBV (Epstein Barr virus) infection. This reversion was due to restoration of the intrinsic apoptotic pathway, as assessed by relocation of the pro-apoptotic molecule Bax to mitochondria, loss of mitochondrial integrity and activation of the caspase cascade with PARP (poly ADP ribose polymerase) cleavage. EBV sensitized TP53-mutated BL cells to all spindle poisons tested, including vincristine and taxol, an effect that was systematically downmodulated by pretreatment of cells with inhibitors of p38 and c-Jun N-terminal kinase (JNK) mitogen-activated protein kinases. Exogenous activation of p38 and JNK pathways by dihydrosphingosine reverted resistance of TP53-mutated BL cells to spindle poisons. Dihydrosphingosine treatment of TP53-deficient Jurkat and K562 cell lines was also able to induce cell death. We conclude that activation of p38 and JNK pathways may revert resistance of TP53-mutated cells to spindle poisons. This opens new perspectives for developing alternative therapeutic strategies when the TP53 gene is inactivated.

Recent advances in Hsp90 inhibitors as antitumor agents.

One promising therapeutic strategy for treating cancer is to specifically target signal transduction pathways that have a key role in oncogenic transformation and malignant progression. Hsp90 is an emerging therapeutic target of interest for the treatment of cancer. It is responsible for modulating cellular response to stress by maintaining the function of numerous signalling proteins - known as 'client proteins' - that are associated with cancer cell survival and proliferation. Many cancers result from specific mutations in, or aberrant expression of, these client proteins. Small molecule Hsp90 inhibitors bind to the ATP binding pocket, inhibit chaperone function and could potentially result in cytostasis or cell death. Consequently, many client proteins are targeted for degradation via the ubiquitin-proteasome pathway including receptor and non receptor kinases (Erb-B2, epidermal growth factor receptor, and Src family kinases), serine/threonine kinases (c-Raf-1 and Cdk4), steroid hormone receptors (androgen and estrogen), and apoptosis regulators such as mutant p53. Inhibition of Hsp90 function has also proven effective in killing cancer cells that have developed resistance to targeted therapies such as kinase inhibitors. This review is intended to update recent developments in new Hsp90 inhibitors as antitumors agents, the design, biological evaluation and their clinical trials studies.

[Antileishmanial activity of five 2- or 3- quinolines by enyne group]. / Activité anti leishmanienne de cinq quinoléines substitutées en position 2- ou 3- par un groupement, enyne.

INTRODUCTION: Leishmaniasis is an emergent orphan disease because of its co-infection with HIV AIDS. We report herein the in vitro biological evalution of five news quinolines, 2- or 3- substituted by an enyne group against Leishmania donovani (MHOM/ET/L82/LV9). PATIENTS AND METHODS: The quinolines has been synthesized by using a cross-coupling reaction between a chloroenyne and an organometallic coumpound in a presence of iron a "green" catalyst. Biological evalution is realized by a colorimetric method with the use of 3-(4,5-dimethylthiazol-2,5-diphényl)-tétrazolium bromide. RESULTS: Determination of the inhibitory concentrations as well as the minimal inhibitory concentrations has shown that the substitution by an enyne group made it possible to have a more important antileishmanial activity. In addition, we have seen that the -2 or the -3 position of the enyne group had no influence in the antileishmanial activity. CONCLUSION: Thus, we have shown the real interest of these quinolines which could be favourably compared with pentamidine, which is currently the reference product, and to consider the use of these quinolines in the treament of the leishmaniasis.

[Antileishmanial activity of five 2- or 3- quinolines by enyne group]. / Activité anti leishmanienne de cinq quinoléines substituées en position 2- ou 3- par un groupement ényne.

INTRODUCTION: Leishmaniasis is an emergent orphan disease because of its co-infection with HIV AIDS. We report herein the in vitro biological evalution of five news quinolines, 2- or 3-substituted by an enyne group against Leishmania donovani (MHOM/ET/L82/LV9). PATIENTS AND METHODS: The quinolines has been synthesized by using a cross-coupling reaction between a chloroenyne and an organometallic coumpound in a presence of iron a "green" catalyst. Biological evalution is realized by a colorimetric method with the use of 3-(4,5-diméthylthiazol-2,5-diphényl)-tetrazolium bromide. RESULTS: Determination of the inhibitory concentrations as well as the minimal inhibitory concentrations has shown that the substitution by an enyne group made it possible to have a more important antileishmanial activity. In addition, we have seen that the -2 or the -3 position of the e nyne group h ad no influence in the antileishmanial activity. CONCLUSION: Thus, we have shown the real interest of these quinolines which could be favourably compared with pentamidine, which is currently the reference p roduct, and to consider the use of these quinolines in the treament of the leishmaniasis.

[New total synthesis of derrusnine]. / Nouvelle synthèse totale de la derrusnine.

The thermal condensation of diethyl 3,4-methylenedioxyphenylmalonate with 3,5-dimethoxyphenol (di-O-methylphloroglucinol) leads to the corresponding 3-(3,4-méthylenedioxyphenyl)-4-hydroxy-5,7-dimethoxycoumarine which is methylated further into derrusnine.

Mechanism of inhibition of tumor necrosis factor production by chlorpromazine and its derivatives in mice.

In previous work, we reported that chlorpromazine inhibits tumor necrosis factor (TNF) production in endotoxin lipopolysaccharide-treated mice, and protects against lipopolysaccharide toxicity. Chlorpromazine is used as an antipsychotic and has several effects on the central nervous system. It acts on different neurotransmitter receptors and has other biochemical activities some of which, like inhibition of phospholipase A2, might be responsible for the inhibitory effect on TNF production. To investigate the role of these actions in the inhibition of TNF production by chlorpromazine, we have synthesized some chlorpromazine derivatives that do not have central activities. Some of these analogs have lost their affinity for various receptors and their phospholipase A2 inhibitory activity, but still inhibit TNF production. No correlation was found between TNF inhibition and the ability to inhibit nitric oxide (NO) synthase, whereas a good correlation was evident between TNF inhibition and antioxidant activity.

Antiinflammatory mechanism of cordiachromene A action.

The mechanism of antiinflammatory action of cordiachromene A, isolated from the chloromethylenic extract of the ascidian Aplidium antillense or chemically synthesized, was studied using different in vivo and in vitro inhibition tests on enzymes of the cyclooxygenase cascade. Cordiachromene A inhibits prostacyclin synthesis and arachidonic acid metabolism but not phospholipase A2 and peroxidase. The mechanism of action, already known to be stereospecific, operates by cyclooxygenase inhibition.

Marine bioactive compounds: stereospecific anti-inflammatory activity of natural and synthetic cordiachromene A.

A new synthesis is proposed for cordiachromene A (CCA), a bioactive component of the ascidian Aplidium antillense Gravier, using a method producing a racemic mixture. The anti-inflammatory activities of a natural extract and a chemically synthetic form of CCA were assessed in vivo by carrageenan-induced rat-paw edema. The activity of synthetic CCA was confirmed by a test on kaolin-induced granuloma in the rat. Strong activities were measured for both CCA, but comparison of results of the first test suggests that only the natural optically active isomer has an anti-inflammatory effect. CCA is similar to indomethacin in its effect on carrageenan-induced rat-paw edema and ten times as active as phenylbutazone.