Muscarinic signaling in carcinoma cells.
Muscarinic signaling in carcinoma cells.
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DOI：
10.1016/s0024-3205(03)00080-8
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发表时间：
2003-03
期刊：
影响因子：
6.1
通讯作者：
Carol L. Williams
中科院分区：
文献类型：
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作者：
Carol L. Williams
我们以前报道过M3毒蕈碱型乙酰胆碱受体（mAChR）的激活产生抗增殖信号，并刺激SCC-9小细胞肺癌（SCLC）细胞系中钙粘蛋白介导的粘附。本研究旨在确定不同SCLC细胞系中功能性mAChR表达的频率，并测试mAChR在不同SCLC细胞系中产生抗增殖信号的能力。还研究了Rac 1在SCLC细胞-细胞粘附中的潜在作用。暴露于mAChR激动剂卡巴胆碱在三种SCLC细胞系（SCC-9、SCC-15和NCI-H146）中诱导稳健的Ca 2+动员（由Ca 2+结合染料Indo-1的细胞内荧光指示），在一种SCLC细胞系（NCI-H209）中诱导适度的Ca 2+动员，在两种SCLC细胞系（SCC-18和NCI-H82）中未检测到Ca 2+动员。M3 mAChR选择性拮抗剂4-二苯基乙酰氧基-N-甲基哌啶甲碘化物抑制所有对卡巴胆碱有反应的SCLC细胞系中的Ca 2+动员。与卡巴胆碱孵育4小时可显著抑制表达功能性mAChR的四种SCLC细胞系中的三种（SCC-9、SCC-15和NCI-H146细胞）的[3 H]胸苷摄取，但不会显著改变检查的其他SCLC细胞系的[3 H]胸苷摄取。这些结果表明，SCLC细胞系通常表达功能性mAChR，当激活时会引发抗增殖信号。为了研究Rac 1在SCLC粘附中的作用，用编码Rac 1、组成型活性Rac 1 Val-12或显性阴性Rac 1 Asn-17的cDNA构建体瞬时转染SCC-9细胞，所述cDNA构建体标记有绿色荧光蛋白（GFP）。与表达GFP-Rac 1或GFP-Rac 1Asn-17的细胞相比，表达GFP标记的组成型活性Rac 1Val-12的SCC-9细胞表现出细胞间粘附增加。组成型活性GFP-Rac 1Val-12，而不是GFP-Rac 1或GFP-Rac 1Asn-17，在SCC-9细胞的细胞-细胞连接处积累。这些结果表明，活化的Rac 1增加SCLC细胞-细胞粘附，这与Rac 1活化有助于mAChR刺激诱导的SCLC细胞-细胞粘附增加的可能性一致。提示mAChR的激活可能在调节SCLC细胞的增殖和粘附中起重要作用。其他研究者证明乙酰胆碱由气道中的多种细胞表达，这支持乙酰胆碱可能激活原发性肿瘤中SCLC细胞表达的mAChR的可能性。
We previously reported that activation of M3muscarinic acetylcholine receptors (mAChR) generates anti-proliferative signals and stimulates cadherin-mediated adhesion in the SCC-9 small cell lung carcinoma (SCLC) cell line. The current study was undertaken to determine the frequency of functional mAChR expression among different SCLC cell lines, and to test the ability of mAChR to generate anti-proliferative signals in different SCLC cell lines. The potential role of Rac1 in SCLC cell-cell adhesion was also investigated. Exposure to the mAChR agonist carbachol induces robust Ca2+mobilization (indicated by intracellular fluorescence of the Ca2+-binding dye Indo-1) in three SCLC cell lines (SCC-9, SCC-15, and NCI-H146), modest Ca2+mobilization in one SCLC cell line (NCI-H209), and no detectable Ca2+mobilization in two SCLC cell lines (SCC-18 and NCI-H82). The M3mAChR-selective antagonist 4-diphenylacetoxy-N-methylpiperidine methiodide inhibits Ca2+mobilization in all SCLC cell lines responding to carbachol. Incubation with carbachol for four hours significantly inhibits [3H]thymidine uptake in three of the four SCLC cell lines expressing functional mAChR (SCC-9, SCC-15, and NCI-H146 cells), but does not significantly alter [3H]thymidine uptake in the other SCLC cell lines examined. These results indicate that SCLC cell lines often express functional mAChR which elicit anti-proliferative signals when activated. To investigate the role of Rac1 in SCLC adhesion, SCC-9 cells were transiently transfected with cDNA constructs coding for Rac1, constitutively active Rac1Val-12, or dominant negative Rac1Asn-17tagged to green fluorescent protein (GFP). SCC-9 cells expressing GFP-tagged constitutively active Rac1Val-12exhibit increased cell-cell adhesion in comparison to cells expressing GFP-Rac1 or GFP-Rac1Asn-17. Constitutively active GFP-Rac1Val-12, but not GFP-Rac1 or GFP-Rac1Asn-17, accumulates at cell-cell junctions in SCC-9 cells. These results indicate that activated Rac1 increases SCLC cell-cell adhesion, consistent with the possibility that Rac1 activation contributes to increased SCLC cell-cell adhesion induced by mAChR stimulation. These findings indicate that activation of mAChR may play a significant role in regulating the proliferation and adhesion of SCLC cells. The demonstration by other investigators that acetylcholine is expressed by a variety of cells in the airways supports the possibility that acetylcholine may activate mAChR expressed by SCLC cells in primary tumors.