Avaliação do Potencial Citotóxico, Genotóxico e Antitumoral do Ditionato de cis-Tetraamino(oxalato)rutênio(III) em Diferentes Linhagens Celulares

• Ano de defesa: 2010
• Autor(a) principal: PEREIRA, Flávia de Castro
• Orientador(a): LACERDA, Elisângela de Paula Silveira
• Tipo de documento: Dissertação
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Mestrado em Biologia
• Departamento: Ciências Biolóicas
• País: BR
• Palavras-chave em Português: Apoptose; atividade antitumoral; A549; citotoxicidade; Ditionato de cis-Tetraamino(oxalato)rutênio(III); genotoxicidade; K562
• Palavras-chave em Inglês: cis-Tetraammine(oxalato)Ruthenium(III) Dithionate; Cytotoxicity; Antitumor activity; A549; K562, Ruthenium(III) compounds; immunomodulatory activity, Apoptosis
• Área do conhecimento CNPq: CNPQ::CIENCIAS BIOLOGICAS::BIOQUIMICA::BIOLOGIA MOLECULAR
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tde/1288

Despite the resounding success of cisplatin and closely related platinum antitumor agents, the movement of other transition-metal antitumor agents toward the clinic has been exceptionally slow. Non-Platinum chemotherapeutic metallopharmaceuticals hold much promise for the future, and needs to be actively explored in a large variety of tumor types in combination therapies. The preparations of metallocomplexes with potential antitumor activity has been one of the main targets of transition metal chemistry since Rosenberg s discovery of cisplatin cisdiamminedichloridoplatinum (II), cis-[Pt(NH3)2Cl2]} cytotoxic activity in the 1960s. In 1978, cisplatin was approved as the first platinumbased drug for the oncology treatment, although several negative side-effects (nephrotoxicity, neurotoxicity, nausea, etc.) had been induced on treated patients. Nevertheless, cisplatin was followed by carboplatin {cis-diammine-1,1´ - yclobutanedicarboxylateplatinum(II), [Pt(NH3)2(cbdc)], approved in 1985} and oxaliplatin 1R,2Rdiamminocyclohexaneoxalatoplatinum(II), [Pt(dach)(ox)], approved in 1996}, which met requirements of improving antitumor activity and reducing disadvantages of cisplatin, carboplatin and oxaliplatin represent the second, and third platinum-based drug generations, respectively. Nowadays, not only platinum-bearing complexes are extensively studied with the aim to broaden a spectrum of transition metal-based complexes which could be used in the treatment of cancer. Ruthenium complexes have shown potential utility in chemotherapy and photodynamic therapy. Ruthenium complexes generally have lower toxicities compared to cisplatin attributed to their specific accumulation in cancer tissues. In vitro and in vivo studies show high anticancer activity of Ruthenium complexes and some of them are currently undergoing clinical trials. In the present work we studied the antitumor activity of the Ruthenium(III) compound cis-Tetraammine(oxalato)Ruthenium(III) Dithionate {cis- [Ru(C2O4)(NH3)4]2(S2O6)} against different tumor and normal cells lineages, analising cell viabilities, cell cycle distribution, apoptosis induction mecanistics and genome DNA damage. Correlation tests were performed to determine the effects of the time of exposure and concentration of Ruthenium complex on mitotic index (MI) and mitotic aberration index on Allium cepa root cells. A comparison of MI results of cis- [Ru(C2O4)(NH3)4]2(S2O6) to those of lead nitrate reveals that the Ruthenium complex demonstrates an average mitotic inhibition eightfold higher than lead, with the frequency of cellular abnormalities almost fourfold lower and mitotic aberration threefold lower. A. cepa root cells exposed to a range of Ruthenium complex concentrations did not display significant clastogenic effects. The cis- Tetraammine(oxalato)Ruthenium(III) Dithionate therefore exhibits a remarkable capacity to inhibit mitosis, perhaps by inhibiting DNA synthesis or blocking the cell cycle in the G2 phase. Results showed that Ruthenium(III) causes a significant reduction of proliferation of A549 cells with viabilities ranging from 55.5% to 24.6% when treated with 40 μM for 24 and 48h; and 32% to 18.2% when treated with 150 μM for 24 and 48h. The Ruthenium(III) compound induced a moderate (31.9% and 39.6% for concentrations 10 and 40 μM, respectively) to high degree (74% for concentration 32 μM) of cytotoxic activity against A549 cells (IC50= 33.72 μM). On the other hand, the normal lung fibroblast MRC-5 did not show significant reduction proliferation in the presence of Ruthenium(III) compound. Even when treated with higher concentrations of cis-Tetraammine(oxalato)Ruthenium(III) Dithionate for 48 hours, MRC-5 cells showed viabilities ranging from 85% to 78,4% for 40 μM and 150 μM, respectively. The antiproliferative and cytotoxic activity revealed that K562 cells cultured with concentrations 40 and 150 μg mL-1 of Ruthenium(III) compound showed significant reduction of proliferation after 72h of exposition, with viabilities ranging from 88.2% to 55.6% when treated with 40 μM for 24 and 72h; and 76.2% to 26.7% when treated with 150 μM for 24 and 72h. The Ruthenium(III) compound induced low [22.4% (24h) to 28.2% (48h) and 29.8% (24h) to 35.7% (48h) for concentrations 10 and 40 μM, respectively] to moderate [44% (24h) and 53% (48h) for concentration 150 μM] of cytotoxic activity against K562. After incubation for 48 h, the IC50 value was 18.28 μM. Compared to the cell cycle profiles of untreated cells, flow cytometric analysis indicated a sub-G1 arresting effect of Ruthenium compound on K562 cells, inducing a 1.7-fold, 2.2-fold and 2.4-fold increase in the number of sub-G1 cells for 24, 48 and 72 h, respectively, when compared to control. The compound also caused a significant increase in tailed cells in any of the concentrations tested compared with negative control that can be associated cytotoxicity with direct effect on K562 cells DNA.