A human mesenchymal spheroid prototype to replace moderate severity animal procedures in leukaemia drug testing

Abstract

Patient derived xenograft, PDX models are regarded as gold standard preclinical models in leukaemia research, especially in testing new drug combinations where typically 45 to 50 animals are used per assay. 9000 animal experiments are performed annually in leukaemia research with these expensive procedures being described as moderate severity, meaning they cause significant pain, suffering and visible distress to animals state. Furthermore, not all clinical leukaemia samples engraft and when they do data turnaround time can be between 6 to 12 months. Heavy dependence on animal models is because clinical leukaemia samples do not proliferate in vitro. Alternative cell line models though popular for drug testing are not biomimetic: they are not dependent on the microenvironment for survival, growth and treatment response and being derived from relapse samples they do not capture the molecular complexity observed at disease presentation. Here we have developed an in vitro platform to rapidly establish co cultures of patient derived leukaemia cells with 3D bone marrow mesenchyme spheroids, BM MSC spheroids. We optimise protocols for developing MSC spheroid leukaemia co-culture using clinical samples and deliver drug response data within a week. Using three patient samples representing distinct cytogenetics we show that patient derived leukaemia cells show enhanced proliferation when co-cultured with MSC spheroids. In addition, MSC spheroids provided improved protection against treatment. This makes our spheroids suitable to model treatment resistance, a major hurdle in current day cancer management. Given this 3Rs approach is 12 months faster in delivering clinical data, is a human cell based biomimetic model and 45 to 50 animals per drug response assay cheaper the anticipated target end users would include academia and pharmaceutical industry. This animal replacement prototype would facilitate clinically translatable research to be performed with greater ethical, social and financial sustainability.

Tunnelling nanotubules are druggable mediators of cancer-niche crosstalk

“…Clinically relevant and human-based animal replacement models are especially warranted in haematological malignancies, where the role of microenvironment in driving treatment resistance is of major significance [7]. Furthermore, transferrable, defined and reproducible coculture [8], spheroid and organoid [9,10] models to efficiently capture leukaemia-niche communications are still emerging. Despite significant advances in human cell-based technologies and state-of-the-art organoid platforms [11], a key limitation remains lack of appropriate ECM that are defined in chemical composition, devoid of animal-derived components such as Matrigel, and display physiologically relevant mechanical properties [12].…”