Fig. 6: The histone deacetylase inhibitor quisinostat rescues IP3R3 expression and enhances cisplatin response in SMARCA4/2-deficient cancer cells. | Nature Communications

Fig. 6: The histone deacetylase inhibitor quisinostat rescues IP3R3 expression and enhances cisplatin response in SMARCA4/2-deficient cancer cells.

From: SMARCA4/2 loss inhibits chemotherapy-induced apoptosis by restricting IP3R3-mediated Ca2+ flux to mitochondria

Fig. 6

a SMARCA2 and ITPR3 mRNA expression in H1703 cells treated with quisinostat for 48 h. Mean ± SD, n = 3 independent experiments, one-way ANOVA followed by Dunnett’s tests for multiple comparisons to untreated, p values (p): left, 10 nM—0.0003, 40 nM < 0.0001; right, 10 nM—0.0027, 40 nM—0.0002. Immunoblots (b) and annexin V+/PI− apoptotic population (c) in H1703 cells treated with cisplatin (3 μM) and quisinostat (10 nM) for 72 h. cl cleaved. Mean ± SD, n = 3 independent experiments, one-way ANOVA followed by Dunnett’s test for multiple comparisons, p values: all <0.0001. d Colony formation assay for H1703 cells treated with cisplatin and quisinostat for 12 days. Immunoblots of H1703 cells ± SMARCA2 knockout (e) or ±IP3R3 knockdown (f) treated with cisplatin (3 μM) and quisinostat (10 nM) for 72 h. g Representative images from confocal live-cell imaging of H1703 cells overexpressing the mitochondrial Ca2+ probe CEPIA-2mt treated with quisinostat or/and cisplatin and stained with the mitochondrial marker Mitotracker deep red. Cisplatin: 2 μM, 24 h; quisinostat: 40 nM, 72 h. Scale bar, 25 μm. h Quantification of basal mitochondrial Ca2+ levels from g, showing the ratio of CEPIA-2mt/Mitotracker fluorescence intensities compared to control. 43 control (ctrl), 42 cisplatin, 38 quisinostat, and 46 quisinostat/cisplatin cells from n = 4 independent experiments were analyzed. Mean ± SD, one-way ANOVA followed by Dunnett’s test for multiple comparisons to ctrl, p values: cisplatin—0.2105, quisinostat—0.2985, combination—0.0032. i Tumor growth in H1703 xenograft models treated with cisplatin (4 mg kg−1) and quisinostat (10 mg kg−1). Vehicle (n = 6 animals), all other groups (n = 5 animals); upper, tumor volume, mean ± SEM, two-way ANOVA; lower, endpoint tumor weight, one-way ANOVA followed by Dunnett’s tests for multiple comparisons to the combination, p values: upper, cisplatin < 0.0001, quisinostat—0.0054; lower, cisplatin—0.0008, quisinostat—0.0330. Representative images (j) and digital quantification (k) of immunohistochemistry analysis in endpoint tumors described in i. Scale bar, 100 μm. Mean ± SD, all groups (n = 5), one-way ANOVA followed by Dunnett’s test for multiple comparisons, p values: all <0.0001. *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001; ns not significant.

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