This study characterizes the transcriptional regulatory mechanisms that drive responses of two patient-derived glioblastoma multiforme (GBM) stem-like cells (PD-GSCs) that have distinct phenotypes - one sensitive and another resistant to the drug pitavastatin. This study investigates the differing mechanisms driving drug response in the two PD-GSCs at the single-cell level, and provides an approach that can be used to infer transcriptional regulatory network models, which can then be used to identify mechanisms driving cell-state transitions, e.g., proneural-to-mesenchymal transitions (PMT), which has been observed experimentally and clinically in GBM. The use of these network models enabled the identification of transcription factor and gene targets that perturbed drug-induced PMT through 1) simulations of network dynamics network, and 2) characterization of gene program activities over the time-course response to drug treatment. These results enabled the identification of multiple siRNAs and the drug vinflunine as secondary components that potentiate the efficacy of pitavastatin. This work demonstrates an approach to uncover the transcriptional network topology (TRN) topology of PD-GSCs, and use it to rationally predict combinatorial treatments that block treatment escape and acquired resistance to drugs in GBM.

Systems Analysis of Single-Cell Heterogeneity Underlying Glioma Drug Resistance