Xie An, Gallant Benjamin, Guo Hao, Gonzalez Alfredo, Clark Matthew, Madigan Audrey, Feng Feng, Chen Hong-Duo, Cui Yali, Dudley Samuel C, Wan Yinsheng
Lifespan Cardiovascular Institute, The Warren Alpert School of Medicine of Brown University and The Providence Veterans Administration Medical Center, Providence, RI 02903, USA.
Department of Medicine, Lillehei Heart Institute, University of Minnesota, Minneapolis, MN 55455, USA.
Oncol Lett. 2018 Aug;16(2):1689-1695. doi: 10.3892/ol.2018.8865. Epub 2018 May 31.
Resting membrane potential (RMP) and intracellular Ca concentration [(Ca)] are involved in tumorigenesis and metastasis. The present study investigated whether functional cardiac Na channels are expressed in human melanoma cells (WM 266-4) and its nonmalignant human melanocytes (HMC), as well as whether they participate in RMP maintenance and Ca homeostasis. Confocal microscopy and western blot analysis were used to detect Na channels. The patch-clamp technique was employed to record Na currents and action potentials. Cytoplasmic Ca was measured by loading Fluo-4. Cardiac (Na1.5) Na channels were expressed in HMCs and WM 266-4 cells. Tetrodotoxin (TTX) dose-dependently blocked Na currents in WM 266-4 while HMCs had no Na currents. Ultraviolet light induced similar action potentials in HMCs and WM 266-4 cells, which were abolished by transient receptor potential A1 channel-specific blocker, HC-030031. Compared with HMCs, RMP was substantially depolarized in WM 266-4. TTX hyperpolarized RMP in WM 266-4 cells at a concentration of 30 µM, which facilitated Ca influx. Compared with HMCs, (Ca) was significantly higher in WM 266-4 cells and was elevated by 30 µM TTX. Collectively, Cardiac Na channels depolarize RMP and inhibit Ca uptake in melanoma cells possibly contributing to tumorigenesis and metastasis. Na channel agonists may be developed to treat melanoma such as WM 266-4.
静息膜电位（RMP）和细胞内钙浓度[（Ca）]与肿瘤发生和转移有关。本研究调查了功能性心脏钠通道是否在人黑色素瘤细胞（WM 266-4）及其非恶性人黑素细胞（HMC）中表达，以及它们是否参与RMP维持和钙稳态。共聚焦显微镜和蛋白质印迹分析用于检测钠通道。采用膜片钳技术记录钠电流和动作电位。通过加载Fluo-4测量细胞质钙。心脏（Na1.5）钠通道在HMC和WM 266-4细胞中表达。河豚毒素（TTX）剂量依赖性地阻断WM 266-4中的钠电流，而HMC没有钠电流。紫外线在HMC和WM 266-4细胞中诱导出相似的动作电位，这些动作电位被瞬时受体电位A1通道特异性阻滞剂HC-030031消除。与HMC相比，WM 266-4中的RMP明显去极化。30μM浓度的TTX使WM 266-4细胞中的RMP超极化，这促进了钙内流。与HMC相比，WM 266-4细胞中的（Ca）显著更高，并且30μM TTX使其升高。总体而言，心脏钠通道使黑色素瘤细胞中的RMP去极化并抑制钙摄取，这可能有助于肿瘤发生和转移。可以开发钠通道激动剂来治疗黑色素瘤，如WM 266-4。
