Kosti, P. | Search bioRxiv

bioRxiv2026

Actionable spatial prostanoid barriers constrain BiTE-driven adoptive T cell immunity in intact human tumors

Adoptive cell therapy (ACT) in solid tumors is limited by tumor microenvironment (TME)-imposed resistance mechanisms that are inadequately addressed by conventional systems. We developed tissue-preserving patient-derived explants (PDEs) from lung and ovarian cancer to interrogate redirected T cell immunity in intact human tissue. Using mesothelin-targeting bispecific T cell engager (BiTE(R), Amgen trademark)-secreting T cells, we observed antigen-dependent but heterogeneous responses across lesions. An integrated ex vivo response score stratified responder and non-responder TMEs, revealing that resistance associates with reduced antigen density, stromal dominance, and limited myeloid licensing rather than baseline lymphocyte abundance. Elevated prostaglandin E2 (PGE2) inversely correlated with BiTE-induced T cell activation, identifying the COX/PGE2 axis as a tissue-imposed constraint. COX inhibition amplified interferon-driven immune programs enhanced intratumoral CD8 infiltration, and increased tumor-restricted apoptosis. Spatial transcriptomics localized these effects to tumor-proximal immune hubs in responders, whereas non-responders remained stromally insulated. These findings position PDEs as human-based new approach methodologies enabling combinatorial ACT pharmacodynamics and stratification. Statement of significancePatient-derived explants provide a human-based new approach methodology to interrogate adoptive immunotherapy pharmacodynamics within intact tumor microenvironments in NSCLC and HGSOC. We uncover a COX/PGE2-mediated tissue ceiling that limits BiTE-driven T cell function and demonstrate that COX inhibition reactivates tumor-proximal immune hubs to enhance intratumoral CD8 infiltration and tumor-restricted apoptosis, informing patient stratification and rational combinations.

systems biology↗

bioRxiv2020

Hypoxia-Sensing CAR T-Cells Provide Safety and Efficacy in Treating Solid Tumors

There has been significant interest in the prospects of chimeric antigen receptor (CAR) T-cell therapy in the treatment of solid malignancies, and multiple clinical trials are in progress 1. However, the scope of these trials has been restricted by the lack of availability of tumor-specific targets to direct CAR binding. Tumor specificity is crucial as on-target off-tumor activation of CAR T-cells in healthy tissues can result in potentially lethal toxicities due to uncontrolled cytokine release syndrome 2. Here we engineer a stringent hypoxia-sensing CAR T-cell system which achieves selective expression of a pan-ErbB-targeted CAR within a solid tumor, a microenvironment characterized by an inadequate oxygen supply. Using murine xenograft models, we demonstrate that despite widespread expression of ErbB receptors in healthy organs, the approach provides anti-tumor efficacy without off-tumor toxicity. This dynamic on/off oxygen-sensing safety switch has the potential to facilitate the unlimited expansion of the CAR T-cell target repertoire for treating solid malignancies.Competing Interest StatementYes there is potential Competing Interest. J.M. is co-founder and chief scientific officer, T.M. is an employee, and D.M.D., D.L.Y. are consultants to Leucid Bio, which is a spinout company focused on development of cellular therapeutic agents. J.N.A., J.M. and P.K. are named inventors on a patent submitted in relation to this work. All other authors have declared that there are no competing financial interests or conflicts of interest in relation to this study.View Full Text

synthetic biology↗