78P - Daily rhythmic expression of pro-tumoral programs in NSCLC shape cancer immunity and therapy response

Background

Circadian rhythms (CRs) are 24-hour cycles involved in fundamental aspects of the organism's physiology, such as cell cycle control, metabolism, or immune responses. While the notion of CR abrogation and cancer is well-known, the specific mechanisms that control rhythmic responses in the tumor microenvironment (TME) are not fully understood. Here, we aim to dissect these programs in NSCLC, with the goal of harnessing circadian biology in a therapeutic setting.

Methods

Using a preclinical model of NSCLC (K-ras^MUTTp53^-/- cell line, KP) orthotopically transferred to C57BL/6 mice, we evaluated daily fluctuations of oncogenic programs, profiled the immune microenvironment, and assessed therapeutic response to anti-PD1 across the day. We also analyzed mice lacking circadian functions in myeloid cells, the main immune infiltrate of KP tumors.

Results

KP tumoral burden showed daily regulation, being higher during the resting phase. Interestingly, transcriptome analysis of FACS-sorted cancer cells over 24h revealed a pro-tumoral program dominated by glycolysis, hypoxia, and mTORC1 increased signaling, which is exacerbated at noon. Strikingly, KP tumors lacking BMAL1 showed increased CD8+ T cell infiltration and reduced tumoral load, suggesting tumor glycolysis controlled by BMAL1, and that its loss promotes anti-tumor immunity. As dendritic cells and CD8+ T cells exert a circadian anti-tumor role in melanoma, we verified whether T cell immunity can be therapeutically exploited in our model. Anti-PD1 efficacy was improved during the active phase, as revealed by a rise in tumor-antigen specific CD8+ T cells, enhanced tumoral clearance and better clinical score. Furthermore, using mice lacking CRs in myeloid cells, we observed different tumor outcomes. Bmal1 loss in neutrophils promoted bigger tumors and more myeloid cell infiltration in KP tumors. Conversely, Bmal1 deletion in CD11c-expressing cells led to lower tumoral burden, being these tumors enriched in cytotoxic CD8+ T cells.

Conclusions

Together, our results suggest time-dependent pro-tumoral mechanisms controlled by BMAL1 in the TME of NSCLC. Dissecting circadian programs controlled by BMAL1 will be key for the proper design of therapeutic interventions in lung cancer.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

The authors.

Funding

Ramón y Cajal Programme 2021; CNIO Excellence Programme; ERC StG 2022.

Disclosure

All authors have declared no conflicts of interest.