Biology subjects

Simula, L.

Publications and source records attributed to Simula, L..

4 recordsLinked to original sources

bioRxiv2026

Monocytes promote intraepithelial infiltration of effector memory CD8+ T cells in regressing tumors

Despite the clinical success of cancer immunotherapies, the cellular interactions driving tumor regression remain incompletely understood. Here, we investigated the dynamic remodeling of the tumor immune microenvironment during regression of transplanted PyMT mammary tumors following STING agonist treatment. Using scRNA-seq of sorted CD8+ T cells and myeloid cells, combined with imaging approaches, we identified major changes in both lymphoid and myeloid compartments during tumor regression. Regressing tumors showed a transient accumulation of Ly6Chi monocyte populations associated with a decline in macrophage subsets, while effector and memory CD8+ T-cell populations increased at the expense of exhausted T cells. Interaction analyses predicted enhanced chemotactic and adhesion interactions between CXCL9+ Ly6Chi monocytes and effector CD8+ T cells. Consistently, dynamic imaging revealed increased CD8+ T-cell motility and infiltration into tumor cores following treatment. In particular, CXCR6+ effector CD8+ T cells transiently accumulated within tumor islets during regression before relocalizing to stromal regions. Together, these findings reveal a coordinated spatiotemporal remodeling of myeloid and CD8+ T-cell populations during immunotherapy-induced tumor regression and highlight cooperative interactions that may promote durable anti-tumor immunity.

immunology↗

bioRxiv2025

An in vivo CRISPR screen unveils top target genes to efficiently improve CAR-T cell persistence in a solid tumour model of lung adenocarcinoma

CAR-T cell therapies are revolutionizing the treatment of refractory and relapsed haematological malignancies, but many patients do not exhibit long-term responses, and these therapies are less effective against solid tumors. Poor persistence of CAR-T cells in patients is associated with therapeutic failure, highlighting the need to identify strategies promoting in vivo expansion. Here, we developed an in vivo competitive screening method to identify genes whose inactivation confers a selective advantage to CAR-T cells. Inactivation of 50 genes in a heterogeneous population of T cells expressing an EGFR-targeting CAR revealed that disruption of REGNASE-1, SOCS1, PTPN2, and P16/NK4A conferred a selective advantage to CAR-T cells in human lung tumor-bearing mice. Consistently, inactivation of these genes improved tumor eradication by CAR-T cells. Interestingly disruption of other genes, described to improve CAR-T cell function in other contexts, had a negative impact in this orthotopic lung tumor model. Further evaluation of long-term effects in a subcutaneous model, highlighted SOCS1 ablation as the most promising strategy for in vivo CAR-T cell amelioration. These results support the importance of evaluating CAR-T cell editing strategies in tumor-specific models and highlight the versatility of our screening approach as a pre-clinical tool for context-specific studies on CAR-T cells amelioration.

immunology↗

bioRxiv2024

Mitochondrial metabolism sustains CD8+ T cellmigration for an efficient infiltration into solid tumors

The ability of CD8+ T cells to infiltrate solid tumors and reach cancer cells is associated with improved patient survival and responses to immunotherapy. Thus, identifying the factors controlling T cell migration in tumors is critical, so that strategies to intervene on these targets can be developed. Although interstitial motility is a highly energy-demanding process, the metabolic requirements of CD8+ T cells migrating in a 3D environment remain unclear. Here, we demonstrate that the tricarboxylic acid (TCA) cycle is the main metabolic pathway sustaining human CD8+ T cell motility in 3D collagen gels and tumor slices while glycolysis plays a much minor role. Using pharmacological and genetic approaches, we report that CD8+ T cell migration depends on the mitochondrial oxidation of glucose and glutamine, but not fatty acids, and both ATP and ROS produced by mitochondria are required for T cells to migrate. Pharmacological interventions to increase mitochondrial activity improve CD8+ T cells intra-tumoral migration and CAR T cell recruitment into tumor islets leading to better control of tumor growth in human xenograft models. Our study highlights the rationale of targeting mitochondrial metabolism to enhance the migration and antitumor efficacy of CAR T cells in treating solid tumors.

immunology↗

bioRxiv2020

PD-1-induced T cell exhaustion is controlled by a Drp1-dependent mechanism

PD-1 signalling downregulates the T cell response, promoting an exhausted state in tumor-infiltrating T cells, through mostly unveiled molecular mechanisms. Drp1-dependent mitochondrial fission plays a crucial role to sustain T cell motility, proliferation, survival and glycolytic engagement and, interestingly, such processes are exactly those inhibited by PD-1 in tumor-infiltrating T cells. Here we show that the signature of PD-1pos CD8+ T cells infiltrating MC38-derived murine tumor mass is having downregulated Drp1 activity and more fused mitochondria, compared to PD-1neg counterparts. Also, PD-1pos lymphocytic elements infiltrating human colon cancer rarely express active Drp1. Mechanistically, PD-1 signalling directly prevents mitochondria fragmentation following T cell stimulation by downregulating Drp1 phosphorylation on Ser616, via regulation of the ERK1/2 and mTOR pathways. In addition, downregulation of Drp1 activity in tumor-infiltrating PD-1pos CD8+ T cells seems to be a mechanism exploited by PD-1 signalling to reduce motility and proliferation of these cells. Overall, our data indicate that the modulation of Drp1 activity in tumor-infiltrating T cells may become a valuable target to ameliorate the anti-cancer immune response in future immunotherapy approaches.

immunology↗