RESUMO
The identification of antitumoral substances is the focus of intense biomedical research. Two structural analogues of thalidomide, LNO3 and L3, are two synthetic compounds that might possess such antitumor properties. We evaluated the toxicological effects of these substances, including cytotoxicity, genotoxicity and induction of apoptosis in HTC cells. Additionally, the production of free radicals (nitric oxide and superoxide) was investigated, and the expression of caspases genes 3, 8, and 9 were determined by RT-qPCR. The compounds exhibited cytotoxic effects that resulted in inhibited cell proliferation. LNO3 showed to be more effective and toxic than L3 in all assays. LNO3 stimulated the release of NO and superoxide, which was accompanied by the formation of peroxynitrite. Apoptosis was induced in a dose-dependent manner by both compounds; however, the expression of caspases 3, 8 and 9 was unchanged. These results suggested that L3 and LNO3 possess antiproliferative and pro-apoptotic effects in HTC cells. Additionally, although they exhibited cytotoxicity, L3 and LNO3 might be useful coadjuvants in tumor treatment studies.
RESUMO
Soybean isoflavonoids have received significant attention due to their potential anticarcinogenic and antiproliferative effects and possible role in many signal transduction pathways. However, their mechanisms of action and their molecular targets remain to be further elucidated. In this paper, we demonstrated that two soybean isoflavones (genistein and daidzein) reduced the proliferation of the human colon adenocarcinoma grade II cell line (HT-29) at concentrations of 25 and 50-100 µM, respectively. We then investigated the effects of genistein and daidzein by RT-PCR on molecules that involved in tumor development and progression by their regulation of cell proliferation. At a concentration of 50 µM genistein, there was suppressed expression of ß-catenin (CTNNBIP1). Neither genistein nor daidzein affected APC (adenomatous polyposis coli) or survivin (BIRC5) expression when cells were treated with concentrations of 10 or 50 µM. These data suggest that the down-regulation of ß-catenin by genistein may constitute an important determinant of the suppression of HT-29 cell growth and may be exploited for the prevention and treatment of colon cancer.
Assuntos
Adenocarcinoma/genética , Adenocarcinoma/patologia , Proteína da Polipose Adenomatosa do Colo/genética , Anticarcinógenos/farmacologia , Processos de Crescimento Celular/efeitos dos fármacos , Processos de Crescimento Celular/genética , Neoplasias do Colo/genética , Neoplasias do Colo/patologia , Expressão Gênica/efeitos dos fármacos , Genisteína/farmacologia , Proteínas Inibidoras de Apoptose/genética , Peptídeos e Proteínas de Sinalização Intracelular/genética , Isoflavonas/farmacologia , Fitoestrógenos/farmacologia , Proteínas Adaptadoras de Transdução de Sinal , Proteína da Polipose Adenomatosa do Colo/metabolismo , Proteína da Polipose Adenomatosa do Colo/fisiologia , Anticarcinógenos/uso terapêutico , Relação Dose-Resposta a Droga , Expressão Gênica/genética , Genisteína/uso terapêutico , Células HT29 , Humanos , Proteínas Inibidoras de Apoptose/metabolismo , Proteínas Inibidoras de Apoptose/fisiologia , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Isoflavonas/uso terapêutico , Fitoestrógenos/uso terapêutico , Fitoterapia , Glycine max , SurvivinaRESUMO
Isoflavones are phenolic compounds widely distributed in plants and found in a high percentage in soybeans. They have important biological properties and are regarded as potential chemopreventive agents. The aim of this study was to verify the preventive effect of two soy isoflavones (genistein and daidzein) by a micronucleus assay, analysis of GST activity, and real-time RT-PCR analysis of GSTa2 gene expression. Mutagens of direct (doxorubicin) and indirect (2-aminoanthracene) DNA damage were used. Hepatoma cells (HTC) were treated with genistein or daidzein for 26 h at noncytotoxic concentrations; 10 µM when alone, and 0.1, 1.0 and 10 µM when combined with genotoxic agents. The micronucleus test demonstrated that both isoflavones alone had no genotoxic effect. Genistein showed antimutagenic effects at 10 µM with both direct and indirect DNA damage agents. On phase II enzyme regulation, the current study indicated an increase in total cytoplasmic GST activity in response to genistein and daidzein at 10 µM supplementation. However, the mRNA levels of GSTa2 isozymes were not differentially modulated by genistein or daidzein. The results point to an in vitro antimutagenic activity of genistein against direct and indirect DNA damage-induced mutagenicity.
