RESUMO
We explore a novel strategy of activating immune signaling through increased micronuclei formation utilizing a cell cycle checkpoint inhibitor to drive cell cycle progression following ionizing radiation. The Chk1/2 inhibitor AZD7762 is used to abrogate radiation therapy (RT)-induced G2/M cell cycle arrest in multiple cell lines and, we find that this therapeutic combination promotes increased micronuclei formation in vitro and subsequently drives increased type I interferon signaling and cytotoxic T-cell activation. In vivo studies using B16-F10 melanoma cancer cells implanted in C57/BL6 mice demonstrate improved rates of tumor control at the abscopal (unirradiated) site, located outside of the radiation field, only in the AZD7762 + RT group, with a corresponding reduction in mean tumor volume, increase in the CD8 T-cell population, and immune activated gene signaling. Our results demonstrate that targeted inhibition of cell cycle checkpoint activation following ionizing radiation drives increased production of immunogenic micronuclei, leading to systemic tumor response with potential future clinical benefit.
Assuntos
Núcleo Celular/efeitos dos fármacos , Núcleo Celular/efeitos da radiação , Quinase 1 do Ponto de Checagem/antagonistas & inibidores , Quinase do Ponto de Checagem 2/antagonistas & inibidores , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos da radiação , Melanoma Experimental/imunologia , Proteínas de Neoplasias/antagonistas & inibidores , Tiofenos/farmacologia , Ureia/análogos & derivados , Animais , Linhagem Celular Tumoral , Feminino , Humanos , Interferon beta/biossíntese , Interferon beta/genética , Melanoma Experimental/tratamento farmacológico , Melanoma Experimental/patologia , Melanoma Experimental/radioterapia , Proteínas de Membrana/biossíntese , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Testes para Micronúcleos , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Interferência de RNA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/farmacologia , Fator de Transcrição STAT1/biossíntese , Fator de Transcrição STAT1/genética , Carga Tumoral/efeitos dos fármacos , Carga Tumoral/efeitos da radiação , Ureia/farmacologia , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Active cell proliferation and turnover in the growth plate is essential for embryonic and postnatal bone growth. We performed a lineage tracing of Wnt/ß-catenin signaling responsive cells (Wnt-responsive cells) using Axin2CreERT2 ;Rosa26ZsGreen mice and found a novel cell population that resides in the outermost layer of the growth plate facing the Ranvier's groove (RG; the perichondrium adjacent to growth plate). These Wnt-responsive cells rapidly expanded and contributed to formation of the outer growth plate from the neonatal to the growing stage but stopped expanding at the young adult stage when bone longitudinal growth ceases. In addition, a second Wnt-responsive sporadic cell population was localized within the resting zone of the central part of the growth plate during the postnatal growth phase. While it induced ectopic chondrogenesis in the RG, ablation of ß-catenin in the Wnt-responsive cells strongly inhibited expansion of their descendants toward the growth plate. These findings indicate that the Wnt-responsive cell population in the outermost layer of the growth plate is a unique cell source of chondroprogenitors involving lateral growth of the growth plate and suggest that Wnt/ß-catenin signaling regulates function of skeletal progenitors in a site- and stage-specific manner. © 2019 American Society for Bone and Mineral Research.
