Transcriptional Repression and Protein Degradation of the Ca(2+)-Activated K(+) Channel K(Ca)1.1 by Androgen Receptor Inhibition in Human Breast Cancer Cells.
Transcriptional Repression and Protein Degradation of the Ca(2+)-Activated K(+) Channel K(Ca)1.1 by Androgen Receptor Inhibition in Human Breast Cancer Cells.
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DOI：
10.3389/fphys.2018.00312
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发表时间：
2018
影响因子：
4
通讯作者：
Ohya S
中科院分区：
文献类型：
--
作者：
Khatun A;Shimozawa M;Kito H;Kawaguchi M;Fujimoto M;Ri M;Kajikuri J;Niwa S;Fujii M;Ohya S
大电导钙激活钾通道KCa1.1在促进乳腺癌细胞增殖和转移中起重要作用。雄激素受体（AR）被提议作为AR阳性晚期三阴性乳腺癌的治疗靶点。我们在此研究了抗雄激素治疗对人乳腺癌MDA-MB-453细胞中KCa 1. 1的功能活性、激活动力学、转录表达和蛋白降解的影响，采用实时PCR、Western印迹、电压敏感染料成像和全细胞膜片钳记录。用抗雄激素比卡鲁胺或Enzalutamide处理48小时，可显著抑制（1）由paxilline（PAX）（一种特异性KCa 1.1阻滞剂）诱导的去极化反应和（2）由去极化电压阶跃诱导的PAX敏感性外向电流。MDA-MB-453细胞中KCa1.1转录本和蛋白质的表达水平显著降低，KCa1.1蛋白质降解主要导致KCa1.1活性降低。在8种调节性β和γ亚基中，LRRC 26单独在MDA-MB-453细胞以及原发性和转移性乳腺癌组织中以高水平表达，而在用抗雄激素处理的MDA-MB-453细胞中未观察到LRRC 26的表达水平和PAX敏感性外向电流的激活动力学的显著变化。用抗雄激素治疗上调MDA-MB-453细胞中泛素E3连接酶FBW 7、MDM 2和MDM 4的表达，并且KCa 1.1的蛋白降解被各自的FBW 7和MDM 2的siRNA介导的阻断显著抑制。基于这些结果，我们得出结论，KCa1.1是AR阳性乳腺癌细胞中的雄激素应答基因，并且通过FBW 7和/或MDM 2增强其蛋白质降解而下调其表达可能至少部分地有助于抗雄激素在乳腺癌细胞中的抗增殖和抗转移作用。
The large-conductance Ca2+-activated K+ channel KCa1.1 plays an important role in the promotion of breast cancer cell proliferation and metastasis. The androgen receptor (AR) is proposed as a therapeutic target for AR-positive advanced triple-negative breast cancer. We herein investigated the effects of a treatment with antiandrogens on the functional activity, activation kinetics, transcriptional expression, and protein degradation of KCa1.1 in human breast cancer MDA-MB-453 cells using real-time PCR, Western blotting, voltage-sensitive dye imaging, and whole-cell patch clamp recording. A treatment with the antiandrogen bicalutamide or enzalutamide for 48 h significantly suppressed (1) depolarization responses induced by paxilline (PAX), a specific KCa1.1 blocker and (2) PAX-sensitive outward currents induced by the depolarizing voltage step. The expression levels of KCa1.1 transcripts and proteins were significantly decreased in MDA-MB-453 cells, and the protein degradation of KCa1.1 mainly contributed to reductions in KCa1.1 activity. Among the eight regulatory β and γ subunits, LRRC26 alone was expressed at high levels in MDA-MB-453 cells and primary and metastatic breast cancer tissues, whereas no significant changes were observed in the expression levels of LRRC26 and activation kinetics of PAX-sensitive outward currents in MDA-MB-453 cells by the treatment with antiandrogens. The treatment with antiandrogens up-regulated the expression of the ubiquitin E3 ligases, FBW7, MDM2, and MDM4 in MDA-MB-453 cells, and the protein degradation of KCa1.1 was significantly inhibited by the respective siRNA-mediated blockade of FBW7 and MDM2. Based on these results, we concluded that KCa1.1 is an androgen-responsive gene in AR-positive breast cancer cells, and its down-regulation through enhancements in its protein degradation by FBW7 and/or MDM2 may contribute, at least in part, to the antiproliferative and antimetastatic effects of antiandrogens in breast cancer cells.
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影响因子：
3.8
作者：
Khaitan D;Sankpal UT;Weksler B;Meister EA;Romero IA;Couraud PO;Ningaraj NS
通讯作者：
Ningaraj NS
影响因子：
5.6
作者：
Khatun A;Fujimoto M;Kito H;Niwa S;Suzuki T;Ohya S
通讯作者：
Ohya S
影响因子：
3.8
作者：
Gong AY;Eischeid AN;Xiao J;Zhao J;Chen D;Wang ZY;Young CY;Chen XM
通讯作者：
Chen XM
影响因子：
8
作者：
Kroiss, A.;Vincent, S.;Allioli, N.
通讯作者：
Allioli, N.
影响因子：
4
作者：
Galli, Francesco;Rossi, Mariangela;Guerrini, Luisa
通讯作者：
Guerrini, Luisa