Genomic Exploration of Distinct Molecular Phenotypes Steering Temozolomide Resistance Development in Patient-Derived Glioblastoma Cells

Temozolomide resistance is a major obstacle in the therapy of glioblastoma. This is also due to the insufficient understanding of glioma heterogeneity in relation to temozolomide resistance. More in depth biological knowledge would benefit the development of different approaches to tackle the problem from its root. We explored the different outcomes derived from the long-term exposure to temozolomide and identified two different behavioral phenotypes associated to specific categories of pathways. In addition, we investigated the intra-tumoral heterogeneity of these phenotypes revealing the complexity of the temozolomide resistance phenomenon. Overall design: Four cell cultures were selected for single cell RNA sequencing. For GS359, GS785, and GS789 the cells sequenced comprised five conditions: control prior treatment (T0-CTRL), control and temozolomide treatment after the first temozolomide exposure (T1-TMZ and T1-CTRL), control and treatment after the last temozolomide treatment (T2-TMZ and T2-CTRL). For GS772 the cells sequenced comprised three conditions: control prior treatment (T0-CTRL), control and temozolomide treatment after the first temozolomide exposure (T1-TMZ and T1-CTRL).