Journal: bioRxiv
Article Title: Predictable clonal hierarchies from restricted progenitors provide a framework for cell type-specific therapies in glioblastoma
doi: 10.64898/2026.02.21.707071
Figure Lengend Snippet: Track-informed combination treatment predictably remodels clonal interaction architecture a) Schematic of the track-informed CellTag lineage tracing and drug perturbation workflow in HOTT. Primary IDH1 WT GBM cells from (n = 3) patient tumors are dissociated and transduced with a high-complexity CellTag lentiviral barcode library encoding combinatorial DNA barcodes and GFP. Barcoded tumor cells are directly transplanted onto human cortical organoids and allowed to engraft and invade toward the organoid center over a 5-7 day period. Following engraftment, organoids are separated and treated with vehicle (DMSO), abemaciclib (1 µM), OTX008 (2.5 µM), or the combination of abemaciclib and OTX008 for 7 days, with drugs refreshed at each media change. At the experimental endpoint, organoids are dissociated and GFP⁺ CellTagged tumor cells are isolated by fluorescence-activated cell sorting (FACS) for single-cell RNA sequencing (scRNA-seq). Lineage relationships are reconstructed by identifying shared CellTag barcode combinations across cells, enabling analysis of treatment-induced changes in clonal architecture. b) UMAP visualization of scRNA-seq profiles from CellTag-labeled GBM cells following treatment in the HOTT (n = 98,474 cells). Cells are colored by treatment condition. c) Fraction of cells assigned to each transcriptional cell type following reference-based mapping from the full CellTag lineage-tracing dataset. d) Clone-member composition shifts (n = 9,138 clones) by cell type following drug treatment. Dot plot shows the log₂ fold change in clone-member representation for each cell type relative to vehicle, computed from unweighted clone-member proportions. For each treatment, the proportion of clone-member cells assigned to each cell type was calculated and normalized to the corresponding vehicle proportion (log₂FC). Dot size represents the magnitude of the log₂ fold change (|log₂FC|), and color denotes directionality (red, enrichment; blue, depletion), with values capped at the 75th percentile. Statistical significance was assessed at the clone level by comparing the distribution of clone-level cell type proportions between each treatment and Vehicle using two-sided unpaired Wilcoxon rank-sum tests, with p-values corrected across all cell type × treatment comparisons using the Benjamini–Hochberg method (**** FDR < 1×10⁻⁴, *** FDR < 1×10⁻³, ** FDR < 1×10⁻², * FDR < 0.05; ns, not significant). e) Top enriched clonal co-occurrence interactions per treatment. For each treatment condition (vehicle, abemaciclib, OTX008, combination), edges represent cell type pairs that co-occur within inferred clones more frequently than expected by chance (log₂ observed/expected), computed from clone × cell type presence matrices. Interactions were filtered to retain pairs with log₂ enrichment ≥ 0.5 and the top 10 strongest enriched pairs per treatment were plotted. Edge thickness denotes log₂ enrichment, and edges are colored by the Track assignment of the recipient cell type. f) UpSet plot of progenitor-progenitor clonal co-occurrence patterns across treatments. Columns denote the top 20 progenitor-progenitor cell type combinations observed within inferred clones; filled circles indicate presence of each progenitor cell type in the combination. The upper bar plot reports intersection size as the fraction of all clones within each treatment exhibiting the corresponding combination, with bars stacked by treatment (vehicle, abemaciclib, OTX008, combination). Fractions are normalized independently within each treatment using the total number of clones in that treatment as the denominator; therefore, stacked bar heights can exceed 100% because per-treatment fractions are summed across conditions. Left bars indicate progenitor set sizes. g) Delta abundance-normalized log₂ enrichment of progenitor-progenitor (PP), progenitor-mature (PM), and mature-mature (MM) cell-cell pairings for each treatment relative to Vehicle. Enrichment values reflect pooled clone-derived cell-cell interactions normalized to overall progenitor abundance. Significance was assessed at the clone level using two-sided Wilcoxon tests with Benjamini-Hochberg correction (* q < 0.05, ** q < 0.01, *** q < 0.001). h) Weighted clone-member Track composition changes relative to Vehicle. Bars show weighted log₂ fold change in Track representation among clone-member cells for each treatment versus Vehicle, with weights defined as 1 / p(Track | Treatment) and baseline Track frequencies computed from all cells. Significance was assessed using clone-level replication (Wilcoxon signed-rank test against 0) with FDR correction (* FDR < 0.05, ** FDR < 0.01, *** FDR < 0.001). i) Clone-level Track interaction residuals for combination treatment. Bars show deviation of the observed Combo effect from the additive expectation of Abemaciclib and OTX008, defined as log₂FC_Combo − (log₂FC_Abemaciclib + log₂FC_OTX008). Residuals were tested against 0 using clone-level replication (Wilcoxon signed-rank test) with FDR correction (* FDR < 0.05, ** FDR < 0.01, *** FDR < 0.001).
Article Snippet: Organoids were treated with vehicle control (DMSO), abemaciclib (1 μM, MedChemExpress), OTX008 (2.5 μM, MedChemExpress), or a combination of abemaciclib and OTX008 for 7 days, with compounds refreshed at each media change.
Techniques: Transduction, Isolation, Fluorescence, FACS, Single Cell, RNA Sequencing, Labeling, Clone Assay, Derivative Assay