Oxidovanadium(IV) complexes with chrysin and silibinin: anticancer activity and mechanisms of action in a human colon adenocarcinoma model.

Vanadium compounds were studied during recent years to be considered as a representative of a new class of nonplatinum metal antitumor agents in combination to its low toxicity. On the other hand, flavonoids are a wide family of polyphenolic compounds synthesized by plants that display many interesting biological effects. Since coordination of ligands to metals can improve the pharmacological properties, we report herein, for the first time, a exhaustive study of the mechanisms of action of two oxidovanadium(IV) complexes with the flavonoids: silibinin Na2[VO(silibinin)22]·6H2O (VOsil) and chrysin [VO(chrysin)2EtOH]2(VOchrys) on human colon adenocarcinoma derived cell line HT-29. The complexes inhibited the cell viability of colon adenocarcinoma cells in a dose dependent manner with a greater potency than that the free ligands and free metal, demonstrating the benefit of complexation. The decrease of the ratio of the amount of reduced glutathione to the amount of oxidized glutathione were involved in the deleterious effects of both complexes. Besides, VOchrys caused cell cycle arrest in G2/M phase while VOsil activated caspase 3 and triggering the cells directly to apoptosis. Moreover, VOsil diminished the NF-kB activation via increasing the sensitivity of cells to apoptosis. On the other hand, VOsil inhibited the topoisomerase IB activity concluding that this is important target involved in the anticancer vanadium effects. As a whole, the results presented herein demonstrate that VOsil has a stronger deleterious action than VOchrys on HT-29 cells, whereby suggesting that Vosil is the potentially best candidate for future use in alternative anti-tumor treatments.

Antiproliferative and apoptosis-inducing activity of an oxidovanadium(IV) complex with the flavonoid silibinin against osteosarcoma cells.

Flavonoids are a large family of polyphenolic compounds synthesized by plants. They display interesting biological effects mainly related to their antioxidant properties. On the other hand, vanadium compounds also exhibit different biological and pharmacological effects in cell culture and in animal models. Since coordination of ligands to metals can improve or change the pharmacological properties, we report herein, for the first time, a detailed study of the mechanisms of action of an oxidovanadium(IV) complex with the flavonoid silibinin, Na2[VO(silibinin)2]·6H2O (VOsil), in a model of the human osteosarcoma derived cell line MG-63. The complex inhibited the viability of osteosarcoma cells in a dose-dependent manner with a greater potency than that of silibinin and oxidovanadium(IV) (p < 0.01), demonstrating the benefit of complexation. Cytotoxicity and genotoxicity studies also showed a concentration effect for VOsil. The increase in the levels of reactive oxygen species and the decrease of the ratio of the amount of reduced glutathione to the amount of oxidized glutathione were involved in the deleterious effects of the complex. Besides, the complex caused cell cycle arrest and activated caspase 3, triggering apoptosis as determined by flow cytometry. As a whole, these results show the main mechanisms of the deleterious effects of VOsil in the osteosarcoma cell line, demonstrating that this complex is a promising compound for cancer treatments.

A new approach for the characterization of proliferative cells in cestodes.

Cestodes show a remarkable proliferative capability that sustains the constant growth and differentiation of proglottids essential for their lifestyle. It is believed that a separate population of undifferentiated stem cells (the so-called germinative cells) are the only cells capable of proliferation during growth and development. The study of this particular cell subpopulation is hampered by the current lack of methods to isolate it. In this work, we developed a reproducible flow cytometry and cell sorting method to quantify and isolate the proliferating cells in the tetrathyridia larvae of the model cestode Mesocestoides corti, based on the DNA content of the cells. The isolated cells display the typical germinative cell morphology, and can be used for RNA isolation with a yield in the ng to µg range. We expect that this approach may facilitate the characterization of the germinative cells in M. corti and other model tapeworms.

Intrachromosomal localization of aberration breakpoints induced by neutrons and gamma rays in Chinese hamster ovary cells.

Chromosome breakpoints induced by neutrons or gamma rays in Chinese hamster ovary cells were mapped to Giemsa-light or Giemsa-dark bands or to band junctions. Radiation-induced breakpoints were found to be distributed nonrandomly according to chromosome or band length. More than 60% of the breakpoints were localized in G-light bands. A group of 13 bands which corresponded to only 7% of the total chromosome length contained 22% of the breakpoints produced by neutrons and 14% of those induced by gamma rays. Seven of these 13 bands are also preferentially damaged by AluI, BamHI and DNase I as reported previously. The results indicate that chromatin and nuclear structure may play a role in the distribution of breakpoints produced by ionizing radiation and endonucleases.

Rolipram versus imipramine in inpatients with major, "minor" or atypical depressive disorder: a double-blind double-dummy study aimed at testing a novel therapeutic approach.

Unlike conventional antidepressants, rolipram stimulates both the presynaptic as well as the postsynaptic component of monoaminergic transmission. Several double-blind comparative trials are on the way to assess the clinical efficacy and safety of this novel compound. The present study was a randomized double-blind double-dummy comparison with imipramine in inpatients with major, "minor" and atypical depressions (DSM III). Results show no relevant differences between rolipram and imipramine regarding efficacy and safety.

Etizolam in the treatment of generalized anxiety disorder: a controlled clinical trial.

A total of 45 patients with generalized anxiety disorder were treated twice daily for 2 weeks, on a double-blind basis, with 0.5 mg etizolam, 0.5 mg alprazolam or 3 mg bromazepam, and symptoms were assessed using Hamilton's rating scale for anxiety and Hamilton's rating scale for depression. Patients then received the same drug for a further 2 weeks, the drugs being given three times daily if a poor response was observed during the first 2 weeks. All drugs displayed equivalent anxiolytic activity after 2 weeks, but etizolam displayed a progressive increase in anxiolytic activity over 4 weeks of treatment. Etizolam also possessed a more marked antidepressant effect than did alprazolam or bromazepam. There were no differences in the tolerability of the three drugs.

Polyoxometalates as antitumor agents: Bioactivity of a new polyoxometalate with copper on a human osteosarcoma model.

Polyoxometalates (POMs) are early transition metal oxygen anion clusters. They display interesting biological effects mainly related to their antiviral and antitumor properties. On the other hand, copper compounds also show different biological and pharmacological effects in cell culture and in animal models. We report herein for the first time, a detailed study of the mechanisms of action of a copper(II) compound of the group of HPOMs with the formula K7Na3[Cu4(H2O)2(PW9034)2]20H2O (PW9Cu), in a model of human osteosarcoma derived cell line, MG-63. The compound inhibited selectively the viability of the osteosarcoma cells in the range of 25-100µM (p<0.01). Besides, we have clearly shown a more deleterious action of PW9Cu on tumor osteoblasts than in normal cells. Cytotoxicity studies also showed deleterious effects for PW9Cu. The increment of reactive oxygen species (ROS) and the decrease of the GSH/GSSG ratio were involved in the antiproliferative effects of PW9Cu. Moreover, the compound caused cell cycle arrest in G2 phase, triggering apoptosis as determined by flow cytometry. As a whole, these results showed the main mechanisms of the deleterious effects of PW9Cu in the osteosarcoma cell line MG-63, demonstrating that this compound is a promissory agent for cancer treatments.

Antitumor properties of a vanadyl(IV) complex with the flavonoid chrysin [VO(chrysin)2EtOH]2 in a human osteosarcoma model: the role of oxidative stress and apoptosis.

Flavonoids, a polyphenolic compound family, and the vanadium compounds have interesting biological, pharmacological, and medicinal properties. We report herein the antitumor actions of the complex [VO(chrysin)2EtOH]2 (VOchrys) on the MG-63 human osteosarcoma cell line. Oxovanadium(IV), chrysin and VOchrys caused a concentration-dependent inhibition of cell viability. The complex was the strongest antiproliferative agent (p < 0.05). Cytotoxicity and genotoxicity studies also showed a concentration effect. Reactive oxygen species (ROS) and the alterations in the GSH/GSSG ratio underlie the main mechanisms of action of VOchrys. Additions of ROS scavengers (vitamin C plus vitamin E) or GSH to the viability experiments demonstrated beneficial effects (p < 0.01). Besides, the complex triggered apoptosis, disruption of the mitochondria membrane potential (MMP), increased levels of caspase 3 and DNA fragmentation measured by the sub-G1 peak in cell cycle arrest experiments (p < 0.01). Collectively, VOchrys is a cell death modulator and a promissory complex to be used in cancer treatments.

Persistence of replicating coxsackievirus B3 in the athymic murine heart is associated with development of myocarditic lesions.

Coxsackievirus B3 (CVB3)-induced myocarditis was studied in euthymic (nu/+) and athymic (nu/nu) C3H/HeN (H-2k) mice. Mice were inoculated intraperitoneally with 10(6) p.f.u. of CVB3 (Nancy strain) and sacrificed at intervals up to 92 days post-inoculation (p.i.). Viraemia peaked at day 2 to 3 p.i. and ceased at day 5 to 7 p.i. in a synchronized manner in both sets of mice. Very few infectious particles were detected in the blood of nu/nu mice after day 14 p.i. In nu/nu mice, CVB3 persisted in myocardial tissue with constant titres between 2.7 +/- 1.9 x 10(4) and 7.6 +/- 5.2 x 10(4) p.f.u./mg from day 3 to 92 p.i., which were comparable to those of nu/+ mice in the acute phase. In nu/+ mice, the virus was recovered from all animals examined by day 11 p.i. and from three out of 13 mice between days 14 and 21 p.i., yet no virus was recovered from nu/+ mice at day 42 p.i. In nu/nu mice, sense and antisense RNA for CVB3 was detected in the myocardial tissue up to day 42 p.i. by in situ hybridization and up to day 92 p.i. by reverse transcriptase-PCR. Neither sense nor antisense RNA was detected after day 21 p.i. in nu/+ mice with the same techniques. Myocardial tissue damage was analysed morphologically. At day 92 p.i., the area of myocardial injury peaked at 23% of the section in nu/nu mice. In contrast, less than 0.6% of tissue sections contained lesions in nu/+ mice. A neutralizing antibody response to CVB3 was observed in both nu/nu and nu/+ mice. The mean titre of neutralizing antibody was significantly higher at day 21 p.i. in nu/+ mice, but similar at day 42 p.i. with nu/nu and nu/+ mice. Perforin-producing natural killer-like cells, which are considered to play an important role in causing acute myocarditic lesions in immunocompetent mice, were found in the lesions of nu/nu mice persistently infected with CVB3. Prolonged tumour necrosis factor-alpha mRNA synthesis detected in nu/nu mice appears to reflect the continuous activation of macrophages, which extend phagocytic reactions to virus-infected myocytes. These immunological results suggested that the host immune response devoid of antigen-specific T cell function is not sufficient to terminate CVB3 infection in nu/nu mice. Also, it appears that competent cellular immunity, on the whole, plays a role in curing rather than in aggravating myocarditis in nu+mice.(ABSTRACT TRUNCATED AT 400 WORDS)