Fig. 6: Nuclear β-catenin interacted with TopoIIα and enhanced its activity, thereby upregulating chemosensitivity to EPI. | Cell Death & Differentiation

Fig. 6: Nuclear β-catenin interacted with TopoIIα and enhanced its activity, thereby upregulating chemosensitivity to EPI.

From: Aquaporin 1 promotes sensitivity of anthracycline chemotherapy in breast cancer by inhibiting β-catenin degradation to enhance TopoIIα activity

Fig. 6

a Immunofluorescence analysis showed the localization of β-catenin and TopoIIα in MDA-MB-231, AQP1/MDA-MB-231, and MDA-MB-231 cells treated with Wnt3a (50 ng/ml) for 24 h (left panel). Insets showed a high-magnification view of the indicated region. Scale bars: 100 μm. The fluorescence intensity in a graph representation and values were expressed as mean ± SEM (χ2 test, **P < 0.01, ***P < 0.001; right panel). b Co-immunoprecipitation with β-catenin antibody in HEK-293T, AQP1/HEK-293T, and HEK-293T+Wnt3a cells showed the interaction of β-catenin with TopoIIα. c The expression (left panel) and catalytic activity (right panel) of TopoIIα were detected in vector/MDA-MB-231 cells and AQP1/MDA-MB-231 cells. d After TopoIIα activity inhibitor etoposide (0.1 μg/ml) treatment for 6 h, vector/MDA-MB-231 and AQP1/MDA-MB-231 cells were treated with EPI (0.5276 μg/ml) or MTX (0.01347 mg/ml) for 48 h, and cell viability was tested by MTT assay. Cell viability of vector/MDA-MB-231 was normalized to 100%. Values were expressed as mean ± SEM (two-tailed Student’s t test, ***P < 0.001). e Vector/MDA-MB-231, shTopoIIα/MDA-MB-231, AQP1/MDA-MB-231, and shTopoIIα/AQP1/MDA-MB-231 cells were treated with EPI (0.5276 μg/ml) or MTX (0.01347 mg/ml) for 48 h, and cell viability was tested by MTT assay. Cell viability of vector/MDA-MB-231 was normalized to 100%. Values were expressed as mean ± SEM (two-tailed Student’s t test, ***P < 0.001). f Cell viability of vector/MDA-MB-231, siβ-catenin/MDA-MB-231, β-catenin/MDA-MB-231, AQP1/MDA-MB-231, siβ-catenin/AQP1/MDA-MB-231, AQP1/β-catenin/MDA-MB-231, and AQP1/β-catenin/MDA-MB-231+etoposide with EPI (0.5276 μg/ml) or MTX (0.01347 mg/ml) treatment for 48 h was tested by MTT assay. Cell viability of vector/MDA-MB-231 was normalized to 100%. Values were expressed as mean ± SEM (two-tailed Student’s t test, **P < 0.01, ***P < 0.001). g The expression (left panel) and catalytic activity (right panel) of TopoIIα were tested in AQP1/MDA-MB-231 cells and siβ-catenin/AQP1/MDA-MB-231 cells. h A schematic illustration of TopoIIα and TopoIIα-CT domain mediated the interaction with β-catenin by co-immunoprecipitation experiments. i, j Cell viability of vector/MDA-MB-231, vector/scr/AQP1/MDA-MB-231, shTopoIIα/AQP1/MDA-MB-231, and TopoIIα-ΔCT/shTopoIIα/AQP1/MDA-MB-231 with different concentration of EPI treatment for 48 h was tested by MTT (i) or ATP/viability (j) assay. Values were expressed as mean ± SEM (two-tailed Student’s t test, *P < 0.05, **P < 0.01). All experiments were independently repeated for three times.

Back to article page