Fig. 5: Labile Zn2+ induces ABCB1-mediated drug extrusion.
a Zn2+ uptake by LLC cells treated with paclitaxel (PTX). ZnCl2 (10 μM) and PTX were added simultaneously. Ctl, no ZnCl2. n = 3. b DOX accumulation (determined by DOX fluorescence in individual cells) and DNA damage (indicated by γ-H2AX expression in individual cells) in LLC-GFP-luc cells co-cultured with MEFs in DMEM + 10% FBS + TPEN (5 μM) for 4 h. TPEN: 50 μM, pre-treating MEFs for 5 min. HEPT: 2 mM. DOX: 3 μM. Median ± interquartile range. RFU, relative fluorescence unit. c ABCB1 expression in LLC-GFP-luc cells co-cultured with mCAFs in DMEM + 10% FBS for 24 h. A representative result from three independent experiments is shown. d LLC-GFP-luc cells viability co-cultured with mCAFs under indicated conditions in DMEM + 10% FBS + 5 μM TPEN for 24 h, determined by luciferase activity. DOX: 3 μM. Mean ± SD, n = 6. Two-tailed t-test. e Inhibition rate of PTX on LLC cells with or without TPEN (0.3 μM) in DMEM determined by CCK8. Mean ± SD, n = 3 for PTX 30 nM group. n = 4 for other groups. One-way ANOVA with multiple comparisons. f Inhibition rate of DOX on LLC-GFP-luc cells with different concentrations of ZnCl2 determined by CCK8. DOX: 3 μM. Cells were treated for 24 h in DMEM + 10% FBS + TPEN (5 μM). Mean ± SEM, n = 3. Two-tailed t-test. g, h ABCB1 expression in LLC-GFP-luc cells treated with indicated concentrations of ZnCl2 for 4 h (g), or with 10 µM ZnCl2 for the indicated time (h). Representative results from three (g) or four (h) independent experiments are shown. i ABCB1 expression on LLC-GFP-luc tumour cells treated with indicated concentrations of ZnCl2 for 4 h. Mean ± SEM, n = 3. Two-tailed t-test. j DOX accumulation in LLC-GFP-luc cells treated with 3 μM DOX combined with indicated concentrations of ZnCl2 for 4 h. Blank: no DOX treatment. Mean ± SEM, n = 4. Two-tailed t-test. k ABCB1 expression in LLC-GFP-luc cells stimulated with ZnCl2 (30 μM) and LY294002 (50 μM) for 3 h. A representative result from three independent experiments is shown. Two-way ANOVA test for curve comparison. Source data are provided as a Source Data file (a–k).
