Analysis of calcium channels roles in cancer cells proliferation

TRPV 2通道在各种组织中表达，包括神经元、神经内分泌细胞、肾和肝中的上皮细胞以及血细胞如巨噬细胞。在本研究中，我们研究了巨噬细胞中TRPV 2通道的调节。当在无血清条件下培养巨噬细胞时，在细胞质中大量检测到TRPV 2的免疫反应性。加入血清诱导一些TRPV 2易位至质膜。趋化肽fMLP进一步诱导TRPV 2易位至质膜。根据这一观察，fMLP增加巨噬细胞中的Cs电流，这被钌红和转染TRPV 2的显性负突变体抑制。PI 3-激酶抑制剂和百日咳毒素预处理可阻断fMLP诱导的TRPV 2易位。当使用fura-2监测胞浆钙浓度（[Ca 2 +]c）时，fMLP诱导[Ca 2 +]c快速而持续的升高，后者被细胞外钙的去除所消除。加入钌红或转染TRPV 2的显性负突变体并不影响[Ca 2 +]c的初始升高，但减弱了fMLP诱导的[Ca 2 +]c升高的持续阶段。加入钌红或转染TRPV 2显性失活突变体均能抑制fMLP诱导的巨噬细胞趋化性。这些结果表明，fMLP诱导TRPV 2易位的PI 3-激酶依赖的机制，这种易位是重要的持续升高[Ca 2 +]c在巨噬细胞。

The TRPV2 channel is expressed in various tissues including neurons, neuroendocrine cells, epithelial cells in the kidney and liver and blood cells such as macrophages. In the present study, we investigated the regulation of the TRPV2 channel in macrophages. When macrophages were cultured in a serum-free condition, immunoreactivity of TRPV2 was detected largely in cytoplasm. Addition of serum induced translocation of some of the TRPV2 to the plasma membrane. A chemotactic peptide fMLP further induced translocation of the TRPV2 to the plasma membrane. In accordance with this observation, fMLP increased the Cs current in macrophage, which was inhibited by ruthenium red and the transfection of the dominant-negative mutant of TRPV2. fMLP-induced translocation of the TRPV2 was blocked by PI 3-kinase inhibitors and pretreatment with pertussis toxin. When cytoplasmic calcium concentration ([Ca2+]c)was monitored by using fura-2, fMLP induced a rapid and sustained elevation of [Ca2+]c, the latter of which was abolished by removal of extracellular calcium. Addition of ruthenium red or transfection of the dominant-negative mutant of TRPV2 did not affect the initial rise in [Ca2+]c but attenuated the sustained phase of fMLP-induced elevation of [Ca2+]c. Finally, addition of ruthenium red or transfection of dominant-negative mutant of TRPV2 inhibited chemotaxis of macrophage induced by fMLP. These results indicate that fMLP induces translocation of TRPV2 by a PI 3-kinase-dependent mechanism and this translocation is important for sustained elevation of [Ca2+]c in macrophage.