Antonella Raffo Romero (Villeneuve d'Ascq / FR), Laurine Lagache (Villeneuve d'Ascq / FR), Nawale Hajjaji (Villeneuve d'Ascq / FR; Lille / FR), Marie Duhamel (Villeneuve d'Ascq / FR), Isabelle Fournier (Villeneuve d'Ascq / FR), Michel Salzet (Villeneuve d'Ascq / FR)
Introduction: Breast cancer (BC) is the most common cancer among women causing the highest number of cancer-related deaths. Currently, BC research is mainly conducted using 2D cultures or mouse models. Both have proven to have limitations: 2D culture lacks cell-cell or cell-matrix interactions and mice are associated with ethical problems and poorly mimic the human diseases. There is an unmet need to develop novel more accurate, realistic, standardisable and robust experimentation models.
Methodology: We have developed BC tumoroids made from a mixture of tumor cells isolated from human and canine BC tissues. In the tumoroid model, we conducted studies to isolate tumoroid-derived subclones with heterogeneous profiles. We analyzed these subclones using proteomics and mass spectrometry imaging to compare them with their parent tumoroids. Our goal was to determine whether the study of these subclones could lead to a more comprehensive treatment strategy that targeting all subclones, potentially reducing post-treatment resistance compared to standard hospital treatment.
Results: Our results show that intratumoral heterogeneity is maintained in the tumoroid model. While many tumoroids exhibited a homogeneous profile, others showed heterogeneity within tumoroids derived from the same patient, which is critical for recapitulating in vivo drug responses. This led us to investigate different subclones within the tumoroids that represent intratumoral heterogeneity. We isolated different subpopulations and used mass spectrometry imaging to demonstrate their similarities to the parent tumoroids. Additionally, proteomic profiling revealed distinct differences between the subclones. Finally, we showed that not all subclones grow and respond uniformly to treatments. The next step is to propose new treatments based on our proteomics analysis that can affect all subclones, thereby preventing relapse in patients.
Conclusion: Our knowledge of biology, combinedwith our skills in proteomics and mass spectrometry imaging helped us to better understand the BC tumoroids and to study the different intratumoral populations that are so problematic today.