Candidate Oligo Therapeutic Target, miR-330-3p, Induces Tamoxifen Resistance in Estrogen Receptor-Positive Breast Cancer Cells via HDAC4

Figure 6

miR-330-3p induces tamoxifen resistance in ER+ breast cancer through downregulating HDAC4. (a, b) MCF7 cells were co-transfected with miR-330-3p mimics and HDAC4 vector or scramble control (NC). MCF7-TR cells were co-transfected with miR-330-3p sponge inhibitor and HDAC4-siRNA (si-HDAC4) or scrambled control (NC). (a) qRT-PCR was performed to detect the mRNA expression of HDAC4. (b) Western blotting identified the protein expression of HDAC4. (c) Co-transfection of miR-330-3p and HDAC4 was carried out in parental cell lines MCF7 and T47D; co-transfection of miR-330-3p sponge inhibitor and HDAC4-siRNA was carried out in resistant MCF7-TR and T47D-TR cell lines. Subsequently, cells were treated with the indicated dose of tamoxifen for 72 h and CCK-8 assay was performed to test cell viability. miR-330-3p could induce tamoxifen resistance in ER+ breast cancer cells through HDAC4 (data are represented as mean ± S.D of triplicate experiments;  < 0.05).

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