RESUMO
The circadian clock is a critical regulator of immunity, and this circadian control of immune modulation has an essential function in host defense and tumor immunosurveillance. Here we use a single-cell RNA sequencing approach and a genetic model of colorectal cancer to identify clock-dependent changes to the immune landscape that control the abundance of immunosuppressive cells and consequent suppression of cytotoxic CD8+ T cells. Of these immunosuppressive cell types, PD-L1-expressing myeloid-derived suppressor cells (MDSCs) peak in abundance in a rhythmic manner. Disruption of the epithelial cell clock regulates the secretion of cytokines that promote heightened inflammation, recruitment of neutrophils and the subsequent development of MDSCs. We also show that time-of-day anti-PD-L1 delivery is most effective when synchronized with the abundance of immunosuppressive MDSCs. Collectively, these data indicate that circadian gating of tumor immunosuppression informs the timing and efficacy of immune checkpoint inhibitors.
Assuntos
Antígeno B7-H1 , Relógios Circadianos , Inibidores de Checkpoint Imunológico , Células Supressoras Mieloides , Animais , Camundongos , Inibidores de Checkpoint Imunológico/uso terapêutico , Inibidores de Checkpoint Imunológico/farmacologia , Células Supressoras Mieloides/imunologia , Células Supressoras Mieloides/metabolismo , Relógios Circadianos/imunologia , Antígeno B7-H1/metabolismo , Antígeno B7-H1/antagonistas & inibidores , Antígeno B7-H1/imunologia , Camundongos Endogâmicos C57BL , Ritmo Circadiano/imunologia , Linfócitos T CD8-Positivos/imunologia , Neoplasias Colorretais/imunologia , Neoplasias Colorretais/terapia , Neoplasias Colorretais/tratamento farmacológico , Microambiente Tumoral/imunologia , Tolerância Imunológica , Humanos , Feminino , Linhagem Celular Tumoral , Análise de Célula Única , Terapia de Imunossupressão , Citocinas/metabolismo , MasculinoRESUMO
An alarming rise in young onset colorectal cancer (CRC) has been reported; however, the underlying molecular mechanism remains undefined. Suspected risk factors of young onset CRC include environmental aspects, such as lifestyle and dietary factors, which are known to affect the circadian clock. We find that both genetic disruption and environmental disruption of the circadian clock accelerate Apc-driven CRC pathogenesis in vivo. Using an intestinal organoid model, we demonstrate that clock disruption promotes transformation by driving Apc loss of heterozygosity, which hyperactivates Wnt signaling. This up-regulates c-Myc, a known Wnt target, which drives heightened glycolytic metabolism. Using patient-derived organoids, we show that circadian rhythms are lost in human tumors. Last, we identify that variance between core clock and Wnt pathway genes significantly predicts the survival of patients with CRC. Overall, our findings demonstrate a previously unidentified mechanistic link between clock disruption and CRC, which has important implications for young onset cancer prevention.
