Establishment of In Vivo Acquired Resistance to Chemotherapy Via Individual Dose Escalation Treatment Regime.

The vast majority of cancer deaths are the result of drug resistance. The lack of superior preclinical models that better reflect the complexity of relapsed disease hinders the development of novel therapeutics. 2D and 3D in vitro cell-based assays have provided some information, but this is limited and does not consider the role of the tumor microenvironment. The development of an in vivo assay can allow to generate resistance, while taking into account the role of the tumor microenvironment and the tumor structure. To achieve this, we have developed an in vivo dose-escalation protocol that models the acquisition of resistance. This model of chemo-resistant neuroblastoma presented with metastases and a genetic signature characteristic of clinical relapsed tumors (Yogev et al. Cancer Res. 79:5382-5393, 2019). We believe that this protocol can be used to generate faithful models for other types of relapse disease; these could serve as reliable tools while developing novel therapies.