Colorectal cancer invasiveness in vitro: Predominant contribution of neonatal Nav1.5 under normoxia and hypoxia
Colorectal cancer invasiveness in vitro: Predominant contribution of neonatal Nav1.5 under normoxia and hypoxia
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DOI：
10.1002/jcp.27399
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发表时间：
2019-05-01
影响因子：
5.6
通讯作者：
Djamgoz, Mustafa B. A.
中科院分区：
文献类型：
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作者：
Guzel, R. Mine;Ogmen, Kazim;Djamgoz, Mustafa B. A.
电压门控钠离子通道(VGSCs)在人体肿瘤中具有功能性表达，可促进肿瘤的体外侵袭和体内转移。据报道，新生儿和成人形式的NaV1.5(分别为nNav1.5和aNav1.5)在结直肠癌(CRCA)细胞中以信使RNA(MRNA)水平表达。本研究对三株CRCA细胞株HT29、HCT116和SW620进行了研究，发现它们表达nNav1.5基因和蛋白。以SW620细胞为模型，研究了选择性靶向nNav1.5或aNav1.5的小干扰RNA(SiRNAs)对(A)通道活性和(B)体外侵袭力的影响。沉默nNav1.5使海流变得更像成年人，并将入侵抑制高达73%。重要的是，随后应用高度特异的通用VGSC阻滞剂河豚毒素(TTX)没有进一步的效果。相反，沉默aNav1.5使电流更像新生儿，但仅抑制17%的侵袭，而TTX仍有显著影响。低氧增加了侵袭性，这也可以被靶向nNav1.5的siRNA完全阻断。雷诺嗪可剂量依赖性地抑制缺氧效应，但在nNav1.5-siRNA预处理的细胞中其作用消失。我们得出的结论是：(A)功能性nNav1.5的表达在人CRCA细胞中是共同的，(B)低氧增加了SW620细胞的侵袭力，(C)VGSC依赖的侵袭力在常氧和低氧条件下都主要由nNav1.5驱动，(D)低氧诱导的侵袭力的增加可能是由nNav1.5的持续电流成分介导的。
Functional expression of voltage-gated Na+ channels (VGSCs) occurs in human carcinomas and promotes invasiveness in vitro and metastasis in vivo. Both neonatal and adult forms of Nav1.5 (nNav1.5 and aNav1.5, respectively) have been reported to be expressed at messenger RNA (mRNA) level in colorectal cancer (CRCa) cells. Here, three CRCa cell lines (HT29, HCT116 and SW620) were studied and found to express nNav1.5 mRNA and protein. In SW620 cells, adopted as a model, effects of gene silencing (by several small interfering RNAs [siRNAs]) selectively targeting nNav1.5 or aNav1.5 were determined on (a) channel activity and (b) invasiveness in vitro. Silencing nNav1.5 made the currents more "adult-like" and suppressed invasion by up to 73%. Importantly, subsequent application of the highly specific, general VGSC blocker, tetrodotoxin (TTX), had no further effect. Conversely, silencing aNav1.5 made the currents more "neonatal-like" but suppressed invasion by only 17% and TTX still induced a significant effect. Hypoxia increased invasiveness and this was also blocked completely by siRNA targeting nNav1.5. The effect of hypoxia was suppressed dose dependently by ranolazine, but its effect was lost in cells pretreated with nNav1.5-siRNA. We conclude that (a) functional nNav1.5 expression is common to human CRCa cells, (b) hypoxia increases the invasiveness of SW620 cells, (c) the VGSC-dependent invasiveness is driven predominantly by nNav1.5 under both normoxic and hypoxic conditions and (d) the hypoxia-induced increase in invasiveness is likely to be mediated by the persistent current component of nNav1.5.