RESUMO
Alcaligenes faecalis is the predominant Gram-negative bacterium inhabiting gut-associated lymphoid tissues, Peyer's patches. We previously reported that an A.â faecalis lipopolysaccharide (LPS) acted as a weak agonist for Toll-like receptorâ 4 (TLR4)/myeloid differentiation factor-2 (MD-2) receptor as well as a potent inducer of IgA without excessive inflammation, thus suggesting that A.â faecalis LPS might be used as a safe adjuvant. In this study, we characterized the structure of both the lipooligosaccharide (LOS) and LPS from A.â faecalis. We synthesized three lipidâ A molecules with different degrees of acylation by an efficient route involving the simultaneous introduction of 1- and 4'-phosphates. Hexaacylated A.â faecalis lipidâ A showed moderate agonistic activity towards TLR4-mediated signaling and the ability to elicit a discrete interleukin-6 release in human cell lines and mice. It was thus found to be the active principle of the LOS/LPS and a promising vaccine adjuvant candidate.
Assuntos
Alcaligenes faecalis/química , Lipídeo A/química , Lipopolissacarídeos/química , Animais , Configuração de Carboidratos , Linhagem Celular , Humanos , Interleucina-6/antagonistas & inibidores , Interleucina-6/metabolismo , Lipídeo A/farmacologia , Lipopolissacarídeos/isolamento & purificação , Lipopolissacarídeos/farmacologia , Camundongos , Receptor 4 Toll-Like/agonistasRESUMO
Four new alkylating N-methylpyrrole-N-methylimidazole (PI) polyamide conjugates (1-4) with seven-base-pair (bp) recognition ability were synthesized. Evaluation of their DNA-alkylating activity clearly showed accurate alkylation at match site(s). The cytotoxicities of conjugates 1-4 were determined against six human cancer cell lines, and the effect of these conjugates on the expression levels of the whole human genome in A549 cells were also investigated. A few genes among the top 20 genes were commonly downregulated by each conjugate, which reflects their sequence specificity. Conversely, many of the top 10 genes were commonly upregulated, which may have been caused by alkylation damage to DNA. Moreover, the antitumor activities of the PI polyamide conjugates 2 and 3 were investigated using nude mice transplanted with DU145 or A549. The intravenous administration of each liposomal conjugate in water yielded tumor-suppressing effects specifically toward DU145 cells and not A549 cells, which was pertinent to cytotoxicity.
Assuntos
Antineoplásicos Alquilantes/síntese química , Imidazóis/síntese química , Nylons/síntese química , Pirróis/síntese química , Animais , Antineoplásicos Alquilantes/química , Antineoplásicos Alquilantes/farmacologia , Linhagem Celular Tumoral , DNA/química , Ensaios de Seleção de Medicamentos Antitumorais , Eletroforese em Gel de Poliacrilamida , Perfilação da Expressão Gênica , Regulação da Expressão Gênica , Genoma Humano , Humanos , Imidazóis/química , Imidazóis/farmacologia , Indóis/síntese química , Indóis/química , Indóis/farmacologia , Lipossomos , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Nylons/química , Nylons/farmacologia , Análise de Sequência com Séries de Oligonucleotídeos , Pirróis/química , Pirróis/farmacologia , Relação Estrutura-Atividade , Transplante HeterólogoRESUMO
Iron-copper cooperative catalysis is shown to be effective for an alkene-Grignard exchange reaction and alkylmagnesiation of alkynes. The Grignard exchange between terminal alkenes (RCHâCH(2)) and cyclopentylmagnesium bromide was catalyzed by FeCl(3) (2.5 mol %) and CuBr (5 mol %) in combination with PBu(3) (10 mol %) to give RCH(2)CH(2)MgBr in high yields. 1-Alkyl Grignard reagents add to alkynes in the presence of a catalyst system consisting of Fe(acac)(3), CuBr, PBu(3), and N,N,N',N'-tetramethylethylenediamine to give ß-alkylvinyl Grignard reagents. The exchange reaction and carbometalation take place on iron, whereas copper assists with the exchange of organic groups between organoiron and organomagnesium species through transmetalation with these species. Sequential reactions consisting of the alkene-Grignard exchange and the alkylmagnesiation of alkynes were successfully conducted by adding an alkyne to a mixture of the first reaction. Isomerization of Grignard reagents from 2-alkyl to 1-alkyl catalyzed by Fe-Cu also is applicable as the first 1-alkyl Grignard formation step.
RESUMO
Phenyl- and vinyllithiums having an alkyl substituent at their ortho- and cis-position, respectively, readily added to alkynes in the presence of 5 mol% of Fe(acac)(3). The reaction of o-(trimethylsilyl)phenyllithium with alkynes gave benzosiloles through an addition-cyclization sequence.