Tumor-suppressive effects of pannexin 1 in C6 glioma cells
Tumor-suppressive effects of pannexin 1 in C6 glioma cells
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DOI：
10.1158/0008-5472.can-06-1396
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发表时间：
2007-02-15
期刊：
影响因子：
11.2
通讯作者：
Naus, Christian C.
中科院分区：
文献类型：
--
作者：
Lai, Charles P. K.;Bechberger, John F.;Naus, Christian C.
哺乳动物间隙连接蛋白，连接蛋白，长期以来一直涉及肿瘤抑制。最近，一个新的蛋白质家族命名为pannexins已被确定为哺乳动物的无脊椎动物的间隙连接蛋白，连接蛋白。迄今为止，据报道，泛连接蛋白I（Panx 1）和泛连接蛋白2（Panx 2）mRNA在脑中表达。大多数肿瘤细胞，包括大鼠C6神经胶质瘤，表现出连接蛋白表达减少，异常间隙连接细胞间通讯（GJIC），和增殖率增加。当缝隙连接蛋白43诱导C6细胞表达上调时，GJIC恢复，增殖减少。在这项研究中，我们研究了C6细胞中Panx 1表达的肿瘤抑制作用。逆转录-PCR分析显示，C6细胞不表达任何的pannexin的成绩单，而其非致瘤性的对应，大鼠原代星形胶质细胞，表现出所有三个pannexins的mRNA。在用标记的Panx 1 [myc]或增强型绿色荧光蛋白（EGFP）I产生稳定的C6转染子时，观察到Panx 1表达定位于高尔基体和质膜。此外，Panx 1转染子表现出扁平的形态，这与纺锤形对照细胞（仅EGFP）有很大不同。此外，Panx 1表达增加间隙连接耦合所示的通过磺酰罗丹明101。最后，我们发现Panx 1在C6细胞中的稳定表达显著降低了细胞单层增殖、细胞运动性、锚定非依赖性生长和无胸腺裸鼠体内肿瘤生长。总而言之，我们得出的结论是，泛连接蛋白表达的丧失可能参与了C6胶质瘤的发展，而Panx 1的恢复则发挥着肿瘤抑制作用。
Mammalian gap junction proteins, connexins, have long been implicated in tumor suppression. Recently, a novel family of proteins named pannexins has been identified as the mammalian counterpart of the invertebrate gap junction proteins, innexins. To date, pannexin I (Panx1) and pannexin 2 (Panx2) mRNAs are reported to be expressed in the brain. Most neoplastic cells, including rat C6 gliomas, exhibit reduced connexin expression, aberrant gap junctional intercellular communication (GJIC), and an increased proliferation rate. When gap junctions are up-regulated by transfecting C6 cells with connexin43, GJIC is restored and the proliferation is reduced. In this study, we examined the tumor-suppressive effects of Panx1 expression in C6 cells. Reverse transcription-PCR analysis revealed that C6 cells do not express any of the pannexin transcripts, whereas its nontumorigenic counterpart, rat primary astrocytes, exhibited mRNAs for all three pannexins. On generation of stable C6 transfectants with tagged Panx1 [myc or enhanced green fluorescent protein (EGFP)I, a localization of Panx1 expression to the Golgi apparatus and plasma membrane was observed. In addition, Panx1 transfectants exhibited a flattened morphology, which differs greatly from the spindle-shaped control cells (EGFP only). Moreover, Panx1 expression increased gap junctional coupling as shown by the passage of sulforhodamine 101. Finally, we showed that stable expression of Panx1 in C6 cells significantly reduced cell proliferation in monolayers, cell motility, anchorage-independent growth, and in vivo tumor growth in athymic nude mice. Altogether, we conclude that the loss of pannexin expression may participate in the development of C6 gliomas, whereas restoration of Panx1 plays a tumor-suppressive role.