Functional expression of the voltage-gated Na+-channel Nav1.7 is necessary for EGF-mediated invasion in human non-small cell lung cancer cells
Functional expression of the voltage-gated Na+-channel Nav1.7 is necessary for EGF-mediated invasion in human non-small cell lung cancer cells
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DOI：
10.1242/jcs.130013
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发表时间：
2013-11-01
影响因子：
4
通讯作者：
Fitzgerald, Elizabeth M.
中科院分区：
文献类型：
--
作者：
Campbell, Thomas M.;Main, Martin J.;Fitzgerald, Elizabeth M.
各种离子通道在人类癌症中表达，其中它们密切参与增殖、血管生成、侵袭和转移。功能性电压门控Na+通道（Na-v）的表达与乳腺癌、前列腺癌、肺癌和结肠癌细胞的转移潜能有关。然而，调节癌症中Na-v表达的细胞机制在很大程度上仍然未知。生长因子是有吸引力的候选者;它们不仅在癌症进展中起关键作用，而且也是非癌细胞中离子通道表达和活性的关键调节剂。在这里，我们研究了表皮生长因子受体（EGFR）信号转导和Na-v在非小细胞肺癌（NSCLC）细胞系中的作用。我们明确地表明，α亚基Na（v）1.7的功能性表达促进H460 NSCLC细胞的侵袭。Na（v）1.7活性（使用河豚毒素）或表达（通过使用小干扰RNA）的抑制使H460细胞侵袭降低高达50%。重要的是，非侵袭性野生型A549细胞缺乏功能性Nav，而Na（v）1.7 α亚基的外源性过表达足以促进这些细胞的TTX敏感性侵袭。EGF/EGFR信号增强H460细胞的增殖、迁移和侵袭，但我们发现，特别是EGFR介导的Na（v）1.7上调对于这些细胞的侵袭行为是必要的。Na（v）1.7在mRNA、蛋白质和功能水平的表达的检测进一步揭示了EGF/EGFR信号通过ERK 1/2途径控制通道表达的转录调节以促进细胞侵袭。患者活检的免疫组织化学证实了Na（v）1.7表达在NSCLC中的临床相关性。因此，Na（v）1.7具有作为治疗干预的新靶点和/或作为NSCLC的诊断或预后标志物的显著潜力。
Various ion channels are expressed in human cancers where they are intimately involved in proliferation, angiogenesis, invasion and metastasis. Expression of functional voltage-gated Na+ channels (Na-v) is implicated in the metastatic potential of breast, prostate, lung and colon cancer cells. However, the cellular mechanisms that regulate Na-v expression in cancer remain largely unknown. Growth factors are attractive candidates; they not only play crucial roles in cancer progression but are also key regulators of ion channel expression and activity in non-cancerous cells. Here, we examine the role of epidermal growth factor receptor (EGFR) signalling and Na-v in non-small cell lung carcinoma (NSCLC) cell lines. We show unequivocally, that functional expression of the a subunit Na(v)1.7 promotes invasion in H460 NSCLC cells. Inhibition of Na(v)1.7 activity (using tetrodotoxin) or expression (by using small interfering RNA), reduces H460 cell invasion by up to 50%. Crucially, non-invasive wild type A549 cells lack functional Nav, whereas exogenous overexpression of the Na(v)1.7 a subunit is sufficient to promote TTX-sensitive invasion of these cells. EGF/EGFR signalling enhances proliferation, migration and invasion of H460 cells but we find that, specifically, EGFR-mediated upregulation of Na(v)1.7 is necessary for invasive behaviour in these cells. Examination of Na(v)1.7 expression at mRNA, protein and functional levels further reveals that EGF/EGFR signalling via the ERK1/2 pathway controls transcriptional regulation of channel expression to promote cellular invasion. Immunohistochemistry of patient biopsies confirms the clinical relevance of Na(v)1.7 expression in NSCLC. Thus, Na(v)1.7 has significant potential as a new target for therapeutic intervention and/or as a diagnostic or prognostic marker in NSCLC.