Immune-competent 3D InSightTM tumour models as novel platform to assess combinatorial biologics therapy

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Abstract Background Immunotherapy has revolutionized cancer treatment, but clinical success is still limited to a subset of patients, underlining the need for novel therapeutic targets. Available ex vivo platforms for drug screening show limitations due to only partial recapitulation of tumor-intrinsic features and of the interactions of tumours with stromal/immune cells. Here, we review our 3D InSightTM tumour models, a complex platform allowing us to study the efficacy of immune-targeting agents on tumour infiltration and killing by peripheral blood mononuclear cells (PBMCs) using clinically relevant models of 3D tumour microtissues from patient-derived xenografts (PDX) with high translational potential. Methods Lung carcinoma GFP-A549 cells were cultured with dermal fibroblasts and PBMCs in Akura 96/384-well plates. To generate a pro-inflammatory tumour microenvironment, PBMCs were activated with cytokines, anti-CD3/CD28 or their combination. We assessed the effect of PD-1 inhibitors in combination with cytokines for potential synergistic anti-cancer effects. 3D InSight™ tumour Microtissue from Melanoma PDX were labeled with CellTracker to monitor for tumour cell viability once exposed to PBMCs. Killing activity and effector function of T cells were evaluated by measuring tumour microtissue size by automatic stage fluorescence microscopy and measuring release of IL-6, TNF, IFNγ and GM-CSF with a MAGPIXTM Luminex system over time. Immune tumour infiltration was quantified and the impact on survival was assessed histologically. Results Combination treatment with cytokines and anti-PD-1 led to higher release of IL-6/TNF/IFNγ/GM-CSF and increased tumour microtissue infiltration by CD8+ T cells, resulting in enhanced tumour killing. Conclusion Our 3D InSightTM tumour models can be successfully employed for optimal high throughput screening of biologics to unveil the efficacy and anti-tumour properties of immune-targeting therapeutic agents. Legal entity responsible for the study InSphero. Funding InSphero AG. Disclosure All authors have declared no conflicts of interest.