Fulgenzi Gianluca, Graciotti Laura, Faronato Monica, Soldovieri Maria Virginia, Miceli Francesco, Amoroso Salvatore, Annunziato Lucio, Procopio Antonio, Taglialatela Maurizio
Department of Molecular Pathology and Innovative Therapies, Polytechnic University of Marche, Via Ranieri, Ancona 60131, Italy.
Int J Biochem Cell Biol. 2006;38(7):1146-59. doi: 10.1016/j.biocel.2005.12.003. Epub 2006 Jan 17.
Given the pivotal role of ion channels in neoplastic transformation, the aim of the present study has been to assess possible differences in the expression patterns of voltage-gated monovalent cationic (Na(+) and K(+)) currents between normal and neoplastic mesothelial cells (NM, MPM, respectively), and to evaluate the role of specific ion channels in mesothelioma cells proliferation, apoptosis, and motility. To achieve this aim, membrane currents expressed in NM and MPM cells derived from surgically-removed human specimens were investigated by means of patch-clamp electrophysiology. NM cells were found to express three main classes of K(+) currents, which were defined as K(IR), maxiK(Ca), and K(V) currents on the basis of their biophysical and pharmacological properties. Each of these K(+) currents was absent in MPM cells; by contrast, MPM cells revealed the novel appearance of tetrodotoxin (TTX)-sensitive voltage-gated Na(+) currents undetected in normal mesothelial cells. Reverse transcriptase-polymerase chain reaction (RT-PCR) and real-time PCR analysis of MPM cells transcripts showed significant expression of the mRNAs encoding for Na(V)1.2, and Na(V)1.6, and Na(V)1.7 (and less so for Na(V)1.3, Na(V)1.4, and Na(V)1.5) main voltage-gated sodium channel (VGSC) alpha-subunit(s). Interestingly, blockade of VGSCs with TTX decreased mesothelioma cell migration in in vitro motility assays; on the other hand, TTX failed to interfere with cell viability, proliferation, and apoptosis progression triggered by UV exposure. In summary, the results of the present study suggest that VGSCs expression in MPM cells may favor the increased motility of the neoplastic cells, a phenotypic feature often associated with the malignant phenotype.
鉴于离子通道在肿瘤转化中的关键作用，本研究的目的是评估正常和肿瘤性间皮细胞（分别为NM和MPM）之间电压门控单价阳离子（Na⁺和K⁺）电流表达模式的可能差异，并评估特定离子通道在间皮瘤细胞增殖、凋亡和运动中的作用。为实现这一目标，通过膜片钳电生理学研究了手术切除的人体标本来源的NM和MPM细胞中表达的膜电流。发现NM细胞表达三类主要的K⁺电流，根据其生物物理和药理学特性将其定义为K(IR)、maxiK(Ca)和K(V)电流。MPM细胞中不存在这些K⁺电流中的任何一种；相反，MPM细胞显示出在正常间皮细胞中未检测到的对河豚毒素（TTX）敏感的电压门控Na⁺电流的新出现。对MPM细胞转录本进行逆转录聚合酶链反应（RT-PCR）和实时PCR分析显示，编码Na(V)1.2、Na(V)1.6和Na(V)1.7（以及编码Na(V)1.3、Na(V)1.4和Na(V)1.5的程度较低）的主要电压门控钠通道（VGSC）α亚基的mRNA有显著表达。有趣的是，在体外运动试验中，用TTX阻断VGSCs可降低间皮瘤细胞的迁移；另一方面，TTX未能干扰紫外线照射引发的细胞活力、增殖和凋亡进程。总之，本研究结果表明，MPM细胞中VGSCs的表达可能有利于肿瘤细胞运动性的增加，这是一种通常与恶性表型相关的表型特征。
