RESUMO
Antibody-drug conjugates (ADC) target cytotoxic drugs to antigen-positive cells for treating cancer. After internalization, ADCs with noncleavable linkers are catabolized to amino acid-linker-warheads within the lysosome, which then enter the cytoplasm by an unknown mechanism. We hypothesized that a lysosomal transporter was responsible for delivering noncleavable ADC catabolites into the cytoplasm. To identify candidate transporters, we performed a phenotypic shRNA screen with an anti-CD70 maytansine-based ADC. This screen revealed the lysosomal membrane protein SLC46A3, the genetic attenuation of which inhibited the potency of multiple noncleavable antibody-maytansine ADCs, including ado-trastuzumab emtansine. In contrast, the potencies of noncleavable ADCs carrying the structurally distinct monomethyl auristatin F were unaffected by SLC46A3 attenuation. Structure-activity experiments suggested that maytansine is a substrate for SLC46A3. Notably, SLC46A3 silencing led to relative increases in catabolite concentrations in the lysosome. Taken together, our results establish SLC46A3 as a direct transporter of maytansine-based catabolites from the lysosome to the cytoplasm, prompting further investigation of SLC46A3 as a predictive response marker in breast cancer specimens.
Assuntos
Antineoplásicos Fitogênicos/metabolismo , Imunoconjugados/metabolismo , Maitansina/metabolismo , Proteínas de Membrana Transportadoras/metabolismo , Antineoplásicos Fitogênicos/administração & dosagem , Linhagem Celular Tumoral , Citoplasma/metabolismo , Sistemas de Liberação de Medicamentos , Humanos , Imunoconjugados/administração & dosagem , Lisossomos/metabolismo , Maitansina/administração & dosagemRESUMO
The Cell division cycle 7 (Cdc7) protein kinase is essential for DNA replication and maintenance of genome stability. We systematically explored thiazole-based compounds as inhibitors of Cdc7 kinase activity in cancer cells. Our studies resulted in the identification of a potent, selective Cdc7 inhibitor that decreased phosphorylation of the direct substrate MCM2 in vitro and in vivo, and inhibited DNA synthesis and cell viability in vitro.
Assuntos
Proteínas de Ciclo Celular/antagonistas & inibidores , Inibidores de Proteínas Quinases/síntese química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Tiazóis/síntese química , Tiazóis/farmacologia , Animais , Domínio Catalítico , Proteínas de Ciclo Celular/química , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Técnicas de Química Sintética , Feminino , Células HCT116 , Humanos , Concentração Inibidora 50 , Masculino , Camundongos , Componente 2 do Complexo de Manutenção de Minicromossomo/metabolismo , Simulação de Acoplamento Molecular , Fosforilação/efeitos dos fármacos , Inibidores de Proteínas Quinases/química , Inibidores de Proteínas Quinases/metabolismo , Proteínas Serina-Treonina Quinases/química , Proteínas Serina-Treonina Quinases/metabolismo , Ratos , Relação Estrutura-Atividade , Tiazóis/química , Tiazóis/metabolismo , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
We describe the structural optimization of a lead compound 1 that exhibits dual inhibitory activities against FLT3 and CDK4. A series of pyrido[4',3':4,5]pyrrolo[2,3-d]pyrimidine derivatives was synthesized, and SAR analysis, using cell-based assays, led to the discovery of 28 (AMG 925), a potent and orally bioavailable dual inhibitor of CDK4 and FLT3, including many FLT3 mutants reported to date. Compound 28 inhibits the proliferation of a panel of human tumor cell lines including Colo205 (Rb(+)) and U937 (FLT3(WT)) and induced cell death in MOLM13 (FLT3(ITD)) and even in MOLM13 (FLT3(ITD, D835Y)), which exhibits resistance to a number of FLT3 inhibitors currently under clinical development. At well-tolerated doses, compound 28 leads to significant growth inhibition of MOLM13 xenografts in nude mice, and the activity correlates with inhibition of STAT5 and Rb phosphorylation.
