RESUMO
ABT-737 is a novel and potent Bcl-2 antagonist with single-agent activity against small-cell lung cancer (SCLC) cell lines. Here, we evaluated the contribution of Bcl-2 family members to the in vitro cellular response of several SCLC cell lines to ABT-737. Relatively higher levels of Bcl-2, Bcl-X(L), Bim and Noxa, and lower levels of Mcl-1 characterized naïve SCLC cell lines that were sensitive to ABT-737. Conversely, a progressive decrease in the relative levels of Bcl-2 and Noxa and a progressive increase in Mcl-1 levels characterized the increased resistance of H146 cells following chronic exposure to ABT-737. Knockdown of Mcl-1 with small interfering RNA sensitized two resistant SCLC cell lines H196 and DMS114 to ABT-737 by enhancing the induction of apoptosis. Likewise, up-regulation of Noxa sensitized H196 cells to ABT-737. Combination treatment with DNA-damaging agents was extremely synergistic with ABT-737 and was associated with the down-regulation of Mcl-1 and the up-regulation of Noxa, Puma, and Bim in H196 cells. Thus, SCLC cells sensitive to ABT-737 expressed the target proteins Bcl-2 and Bcl-X(L), whereas Mcl-1 and factors regulating Mcl-1 function seem to contribute to the overall resistance of SCLC cells to ABT-737. Overall, these observations provide further insight as to the mechanistic bases for ABT-737 efficacy in SCLC and will be helpful for profiling patients and aiding in the rational design of combination therapies.
Assuntos
Compostos de Bifenilo/farmacologia , Carcinoma de Células Pequenas/tratamento farmacológico , Carcinoma de Células Pequenas/metabolismo , Neoplasias Pulmonares/tratamento farmacológico , Neoplasias Pulmonares/metabolismo , Nitrofenóis/farmacologia , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Sulfonamidas/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Apoptose/efeitos dos fármacos , Proteínas Reguladoras de Apoptose/biossíntese , Proteínas Reguladoras de Apoptose/genética , Proteína 11 Semelhante a Bcl-2 , Compostos de Bifenilo/administração & dosagem , Carboplatina/administração & dosagem , Carcinoma de Células Pequenas/patologia , Processos de Crescimento Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Regulação para Baixo , Sinergismo Farmacológico , Etoposídeo/administração & dosagem , Humanos , Neoplasias Pulmonares/patologia , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Proteína de Sequência 1 de Leucemia de Células Mieloides , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Nitrofenóis/administração & dosagem , Piperazinas/administração & dosagem , Piperazinas/farmacologia , Proteínas Proto-Oncogênicas/biossíntese , Proteínas Proto-Oncogênicas/genética , Proteínas Proto-Oncogênicas c-bcl-2/biossíntese , Proteínas Proto-Oncogênicas c-bcl-2/genética , RNA Interferente Pequeno/genética , Sulfonamidas/administração & dosagem , Transfecção , Regulação para CimaRESUMO
In this report, we describe the antitumor activity of A-289099, an indolyloxazoline derivative with antimitotic activity. A-289099 decreased the proliferation of a variety of cells with EC(50) values ranging from 5.1 to 12.8 nM in a P-glycoprotein-independent manner. In cultured cells, microtubules depolymerized in a time- and dose-dependent manner when treated with A-289099. In competition-binding assays, A-298099 competed with [(3)H]colchicine for binding to tubulin (K(i) = 0.65 micro M); however, it did not compete with [(3)H]paclitaxel or [(3)H]vincristine. There was an accumulation of cells in G(2)-M after treatment with A-289099 for 8 h and a subsequent increase in a subdiploid population and an increase in caspase-3 activity, indicative of apoptosis after treatment for 24 and 48 h. The antitumor activities of A-289099 were evaluated using the syngeneic M5076 murine reticulum sarcoma flank tumor model. Animals size-matched for established tumors ( approximately 350 mm(3)) were dosed p.o. (50 mg/kg every day) for 11 days starting on day 10 postinoculation. Tumors from A-289099-treated animals regressed throughout the 11-day dosing period with a percentage of the average treated-tumor-volume divided by the average vehicle-control-tumor-volume (% T/C) value of 11% after treatment for 7 days. Examination of tumor sections revealed an increase in internucleosomal DNA fragmentation or cell death within the central core after drug-treatment. A decrease in the perfusion of tumors was observed after drug-treatment that was localized primarily to the central core and closely associated with the regions of cell death. In summary, our findings indicate A-289099 is a promising, orally active tubulin-binding compound with antitumor activity in vivo.
Assuntos
Antineoplásicos/uso terapêutico , Indóis/uso terapêutico , Oxazóis/uso terapêutico , Sarcoma Experimental/tratamento farmacológico , Tubulina (Proteína)/metabolismo , Administração Oral , Animais , Antineoplásicos/metabolismo , Apoptose/efeitos dos fármacos , Sítios de Ligação , Caspase 3 , Caspases/metabolismo , Ciclo Celular/efeitos dos fármacos , Proteínas de Ciclo Celular/metabolismo , Divisão Celular/efeitos dos fármacos , Colchicina/metabolismo , Relação Dose-Resposta a Droga , Feminino , Humanos , Marcação In Situ das Extremidades Cortadas , Indóis/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Mitose/efeitos dos fármacos , Oxazóis/metabolismo , Paclitaxel/farmacologia , Sarcoma Experimental/metabolismo , Sarcoma Experimental/patologia , Células Tumorais Cultivadas/efeitos dos fármacos , Células Tumorais Cultivadas/metabolismo , Vincristina/farmacologiaRESUMO
A series of indole containing oxazolines has been discovered as a result of structural modifications of the lead compound A-105972. The compounds exert their anticancer activity through inhibition of tubulin polymerization by binding at the colchicine site. A-289099 was identified as an orally active antimitotic agent active against various cancer cell lines including those that express the MDR phenotype. The anticancer activity, pharmacokinetics, and an efficient and enantioselective synthesis of A-289099 are described.