RESUMO
The assembly and disassembly of FtsZ play an essential role in bacterial cell division. Using single-cell imaging, we report that short exposure to BT-benzo-29 inhibits Z-ring formation in live Bacillus subtilis cells. Fluorescence recovery after photobleaching of the Z-ring in live bacteria demonstrated that BT-benzo-29 strongly suppressed the assembly dynamics of FtsZ in the Z-ring. Furthermore, B. subtilis cells expressing V275A-FtsZ resisted the antibacterial activity of BT-benzo-29 providing evidence that BT-benzo-29 inhibits bacterial proliferation by targeting FtsZ. In addition, a brief (8 min) exposure of BT-benzo-29 destroyed the Z-ring without perturbing the localization of a late cell division protein, DivIVA, the nucleoid segregation, and membrane permeability. BT-benzo-29, when used in combination with vancomycin and polymyxin B (PMB), produced a much stronger inhibitory effect on Bacillus subtilis and Escherichia coli cells, respectively. The combination index of BT-benzo-29 with vancomycin and PMB was determined to be <1, suggesting that BT-benzo-29 exhibits synergistic inhibitory effects on bacterial proliferation when used along with these antibiotics.
Assuntos
Antibacterianos/farmacologia , Bacillus subtilis/efeitos dos fármacos , Proteínas de Bactérias/antagonistas & inibidores , Benzimidazóis/farmacologia , Divisão Celular/efeitos dos fármacos , Proteínas do Citoesqueleto/antagonistas & inibidores , Farmacorresistência Bacteriana/genética , Tiofenos/farmacologia , Substituição de Aminoácidos , Bacillus subtilis/genética , Bacillus subtilis/crescimento & desenvolvimento , Bacillus subtilis/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Permeabilidade da Membrana Celular/efeitos dos fármacos , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Combinação de Medicamentos , Sinergismo Farmacológico , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Recuperação de Fluorescência Após Fotodegradação , Expressão Gênica , Testes de Sensibilidade Microbiana , Mutação , Polimixina B/farmacologia , Análise de Célula Única , Vancomicina/farmacologiaRESUMO
Combretastatin A-4 (CA-4) in phosphate and serine pro-drug forms is under phase II clinical trials. With our interest of discovering CA-4 inspired new chemical entities, a novel series of 4,5-diaryl-2-aminoimidazole analogues of the compound was designed and synthesized by an efficient and diversity feasible route involving atom economical arene C-H bond arylation. Interestingly, four compounds showed potent cell-based antiproliferative activities in nanomolar concentrations. Among the compounds, compound 12 inhibited the proliferation of several types of cancer cells much more efficiently than CA-4. It depolymerized microtubules, induced spindle defects, and stalled mitosis in cells. Compound 12 bound to tubulin and inhibited the polymerization of tubulin in vitro. In addition, podophyllotoxin and CA-4 inhibited the binding of compound 12 to tubulin. The distinctive pharmacophoric features of the bridging motif as well as quinoline nucleus were explored. We noted also a valuable quality of compound 12 as a potential probe in characterizing new CA-4 analogues.