RESUMO
Identifying novel drug targets to overcome resistance to tyrosine kinase inhibitors (TKIs) and eradicating leukemia stem/progenitor cells are required for the treatment of chronic myelogenous leukemia (CML). Here, we show that ubiquitin-specific peptidase 47 (USP47) is a potential target to overcome TKI resistance. Functional analysis shows that USP47 knockdown represses proliferation of CML cells sensitive or resistant to imatinib in vitro and in vivo. The knockout of Usp47 significantly inhibits BCR-ABL and BCR-ABLT315I-induced CML in mice with the reduction of Lin-Sca1+c-Kit+ CML stem/progenitor cells. Mechanistic studies show that stabilizing Y-box binding protein 1 contributes to USP47-mediated DNA damage repair in CML cells. Inhibiting USP47 by P22077 exerts cytotoxicity to CML cells with or without TKI resistance in vitro and in vivo. Moreover, P22077 eliminates leukemia stem/progenitor cells in CML mice. Together, targeting USP47 is a promising strategy to overcome TKI resistance and eradicate leukemia stem/progenitor cells in CML.
Assuntos
Resistencia a Medicamentos Antineoplásicos , Leucemia Mielogênica Crônica BCR-ABL Positiva/patologia , Células-Tronco Neoplásicas/metabolismo , Células-Tronco Neoplásicas/patologia , Inibidores de Proteínas Quinases/farmacologia , Ubiquitina Tiolesterase/metabolismo , Proteases Específicas de Ubiquitina/metabolismo , Animais , Proliferação de Células/efeitos dos fármacos , Dano ao DNA , Reparo do DNA/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , MAP Quinases Reguladas por Sinal Extracelular/metabolismo , Proteínas de Fusão bcr-abl , Regulação Leucêmica da Expressão Gênica/efeitos dos fármacos , Humanos , Células K562 , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Camundongos Knockout , Complexo de Endopeptidases do Proteassoma/metabolismo , Ligação Proteica/efeitos dos fármacos , Estabilidade Proteica/efeitos dos fármacos , Proteólise/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Fator de Transcrição STAT5/metabolismo , Transdução de Sinais/efeitos dos fármacos , Tiofenos/farmacologia , Ensaios Antitumorais Modelo de Xenoenxerto , Proteína 1 de Ligação a Y-Box/metabolismo , Proteínas ras/metabolismoRESUMO
The spindle assembly checkpoint prevents chromosome mis-segregation during mitosis by delaying sister chromatid separation. Several F-box protein members play critical roles in maintaining genome stability and regulating cell cycle progress via ubiquitin-mediated protein degradation. Here, we showed that Fbxo6 critically regulated spindle checkpoint and chromosome segregation. Fbxo6 was phosphorylated during mitosis. Overexpression of Fbxo6 lead to faster exit from nocodazole-induced mitosis arrest through premature sister chromatid separation. Moreover, we found substantially more binuclear and multilobed nuclei cells accompanied with impaired cell viability in Fbxo6-overexpressed HeLa cells. Mechanistically, Fbxo6 interacted with spindle checkpoint proteins including Mad2 and BubR1 leading to the premature exit from mitosis. Overall, we revealed a novel role of Fbxo6 in regulating spindle checkpoint, which may shed light on the regulation of genome instability of cancer cells.
