Bose Chhanda, Zhang Hailing, Udupa Kodetthoor B, Chowdhury Parimal
Donald W. Reynolds Department of Geriatrics, University of Arkansas for Medical Sciences, College of Medicine, Little Rock, Arkansas 72205, USA.
Am J Physiol Gastrointest Liver Physiol. 2005 Nov;289(5):G926-34. doi: 10.1152/ajpgi.00138.2005. Epub 2005 Jul 28.
The objectives of the present study were to determine the effect of nicotine on MAPK signaling and on the proliferation of AR42J cells as well as to assess the relationship between MAPK activation and exocrine secretion in these cells. AR42J cells were incubated with nicotine and analyzed for the activation of MAPK by Western blot analysis using their respective antibodies and confirmed by immunohistochemistry. The effect of nicotine on cell proliferation was determined by the spectrophotometric method, and cell function was assessed by cholecystokinin (CCK)-stimulated amylase release into the culture medium. Nicotine at a dose of 100 microM induced phospho-ERK1/2 activation maximally in 3 min compared with untreated cells. Furthermore, immunofluorescence study confirmed the nicotine-induced increase in translocation of phospho-ERK1/2 to the nucleus. Activation of phospho-ERK1/2 was inhibited by an ERK1/2 pathway inhibitor but not by a nicotine receptor antagonist. At the same dose, there was significantly enhanced proliferation of AR42J cells until 72 h without toxic effect, as the percentage of lactate dehydrogenase release remained unchanged. Other MAPKs, c-Jun NH2-terminal kinase 1/2 and p38 MAPK, were not affected by nicotine treatment. At a nicotine dose of 100 microM, the CCK-stimulated release of amylase was maximal at 6 min, and, although a nicotinic receptor antagonist inhibited this response, it was not inhibited by the ERK1/2 pathway inhibitor. We conclude that nicotine treatment induced activation of ERK1/2 and increased the proliferation of AR42J cells. The data further indicate that MAPK signaling by nicotine is independent of the secretory response.
本研究的目的是确定尼古丁对丝裂原活化蛋白激酶（MAPK）信号传导及AR42J细胞增殖的影响，并评估这些细胞中MAPK激活与外分泌之间的关系。将AR42J细胞与尼古丁一起孵育，使用各自的抗体通过蛋白质印迹分析来分析MAPK的激活情况，并通过免疫组织化学进行确认。通过分光光度法确定尼古丁对细胞增殖的影响，并通过胆囊收缩素（CCK）刺激淀粉酶释放到培养基中来评估细胞功能。与未处理的细胞相比，100微摩尔剂量的尼古丁在3分钟内最大程度地诱导了磷酸化细胞外信号调节激酶1/2（phospho-ERK1/2）的激活。此外，免疫荧光研究证实了尼古丁诱导的磷酸化ERK1/2向细胞核转位的增加。磷酸化ERK1/2的激活被ERK1/2途径抑制剂抑制，但未被尼古丁受体拮抗剂抑制。在相同剂量下，直到72小时AR42J细胞的增殖显著增强且无毒性作用，因为乳酸脱氢酶释放的百分比保持不变。其他MAPK，即c-Jun氨基末端激酶1/2和p38 MAPK，不受尼古丁处理的影响。在100微摩尔的尼古丁剂量下，CCK刺激的淀粉酶释放在6分钟时最大，并且，尽管烟碱受体拮抗剂抑制了这种反应，但它未被ERK1/2途径抑制剂抑制。我们得出结论，尼古丁处理诱导了ERK1/2的激活并增加了AR42J细胞的增殖。数据进一步表明，尼古丁的MAPK信号传导与分泌反应无关。
