76P - Immune engager compounds screening using CRC patient-derived organoids

Background

Colorectal cancer (CRC) is the third cause of cancer-related death worldwide. Surgery is the primary treatment followed by radiotherapy and/or chemotherapy which have toxic side effects and can be ineffective. 2D cell cultures and animal models have been used for CRC drug development. Still, they cannot recapitulate the human anatomy or physiology or predict drug efficacy, resistance and toxicity. Patient-derived organoids (PDO) are three-dimensional in vitro stem cell cultures that recapitulate the organs' cell lineage, functions and tumour heterogeneity retaining patients’ tumour antigens and faithfully predicting treatment response. Since PDOs lack the immune microenvironment needed to better predict patients' responses and resistance, we optimised an in vitro CRC organoids and immune cell co-culture protocol to rapidly and efficiently assess CD3- T cell interactions, activation and capacity to recognise and kill tumour organoids using bioengineered T cell engaging bispecific molecules.

Methods

We co-cultured CRC organoids, non-autologous stimulated CD3-T cells in suspension with T cell engager molecules HER2 and EGFR. At the end of each co-culture dose-response assay we assessed organoid viability, CD3-CD4-CD8 T cell viability, activation and killing by time-lapse live cell imaging, flow cytometry and ELISA.

Results

As HER2 and EGFR T cell engager doses were increased, the viability of the organoids substantially dropped. Moreover, CD4+CD25+CD69+ and CD8+CD25+CD69+ T cell populations were detected by flow cytometry in the presence of both T cell engagers' molecules but not in the controls. Finally, higher levels of Interferon-gamma cytokine were observed in the supernatant of co-cultured organoids with HER2 and EGFR molecules compared to the controls.

Conclusions

We have recreated the complex tumour cells and immune microenvironment interaction to successfully profile the efficacy, activity and crosstalk between HER2 and EGFR immune engager compounds, tumour organoids and immune cell subsets across a range of target organoid genotypes and a range of immune cell donors, aiming to replicate patients’ response and prioritise suitable immunotherapy candidates without the need for murine models.

Editorial acknowledgement

Clinical trial identification

Legal entity responsible for the study

Prof. Andrew Beggs Group - The University of Birmingham and AstraZeneca UK Limited.

Funding

AstraZeneca UK Limited.

Disclosure

All authors have declared no conflicts of interest.