Fig. 4. Compound 15 kills metabolically-active human glioblastoma cells in vitro and in 3D structures.

a Representative brightfield and fluorescence images (from three independent experiments) of U87 human glioblastoma cells (20,000 cells/well) treated with compound 15 (red, λ_em 590 nm) or 2-NBDG (green, λ_em 530 nm) (both 100 μM) with or without d-glucose (5 mM) and illuminated or not with ThorLabs M530L3 LED (10 mW, 37 J cm⁻²). Annexin V-Pacific blue (4 μg mL⁻¹) was used as an apoptosis marker (blue, λ_em 450 nm). Scale bar: 10 μm. b Flow cytometric quantification (gating: Supplementary Fig. 5) of apoptotic U87 cells after different treatments. Data presented as mean values ± SD (n = 4 independent experiments). c Size decrease of U87-nlsCrimson 3D spheroids after variable treatments with compound 15 (100 μM) and visible light (10 mW, 37 J cm⁻²). Data presented as mean values ± SEM and normalized to the viability of untreated spheroids (n = 3 independent experiments with three technical replicates). d Representative merged brightfield and fluorescence microscope images (from three independent experiments) of U87-nlsCrimson spheroids where live cells expressed E2Crimson fluorescent protein (λ_em 645 nm, magenta). Spheroids treated with compound 15 plus light showed circumference of dead cells of ~50 μm in diameter (blue bar). Scale bar: 100 μm. P values were obtained from two-tailed unpaired t tests. Source data are available.