Kijima T, Maulik G, Ma P C, Madhiwala Priya, Schaefer E, Salgia R
Department of Medical Oncology, Dana-Farber Cancer Institute, Dana 1234B, 44 Binney Street, Boston, MA 02115, USA.
J Cell Mol Med. 2003 Apr-Jun;7(2):157-64. doi: 10.1111/j.1582-4934.2003.tb00214.x.
Small cell lung cancer (SCLC) is a rapidly progressive disease with ultimate poor outcome. SCLC has been shown to interact closely with the stromal and extracellular matrix (ECM) components of the diseased host. ECM consists of type I/IV collagen, laminin, vitronectin, and fibronectin (FN) among others. Herein, we investigated the behavior of a SCLC cell line (NCI-H446) on FN-coated surface. Over a course of 72 h, FN (10 micro g/ml) caused both increased survival and proliferation of NCI-H446 cells. Survival under serum-starved conditions increased 1.44-fold and proliferation in the presence of fetal calf serum increased by 1.30-fold. The phosphatidylinositol 3-kinase (PI3-K) inhibitor LY294002 reduced both survival and proliferation of NCI-H446 cells (0.48- and 0.27-fold, respectively), even on FN-coated surface. We next determined the effects of FN on cytoskeletal function such as cell motility/morphology and adhesion. Over a course of 24 h, FN reduced aggregation of NCI-H446 cells and induced flattened cellular morphology with neurite-like projections after 1 h, however, in the presence of LY294002, the cells rounded up. Adhesion of NCI-H446 cells also increased with FN (4.47-fold) which was abrogated with LY294002 treatment. This correlated with phosphorylation of the cytoskeletal protein p125FAK, on Tyr397, Tyr861 and Ser843 residues with FN. Even in the presence of LY294002, these serine/tyrosine residues were still phosphorylated on FN-coated surface. In contrast, the focal adhesion protein paxillin was not phosphorylated at Tyr31 with FN. In summary, FN stimulation of SCLC cells leads to enhancement of viability and changes in cytoskeletal function that are partially mediated through the PI3-K pathway.
小细胞肺癌（SCLC）是一种进展迅速、预后极差的疾病。研究表明，SCLC与患病宿主的基质和细胞外基质（ECM）成分密切相互作用。ECM包括I/IV型胶原蛋白、层粘连蛋白、玻连蛋白和纤连蛋白（FN）等。在此，我们研究了一种SCLC细胞系（NCI-H446）在FN包被表面的行为。在72小时的过程中，FN（10微克/毫升）使NCI-H446细胞的存活率和增殖率均增加。血清饥饿条件下的存活率提高了1.44倍，在胎牛血清存在下的增殖率提高了1.30倍。磷脂酰肌醇3-激酶（PI3-K）抑制剂LY294002降低了NCI-H446细胞的存活率和增殖率（分别为0.48倍和0.27倍），即使在FN包被的表面也是如此。接下来，我们确定了FN对细胞骨架功能（如细胞运动/形态和黏附）的影响。在24小时的过程中，FN减少了NCI-H446细胞的聚集，并在1小时后诱导出具有神经突样突起的扁平细胞形态，然而，在LY294002存在的情况下，细胞变圆。NCI-H446细胞与FN的黏附也增加了（4.47倍），LY294002处理可消除这种黏附。这与细胞骨架蛋白p125FAK在Tyr397、Tyr861和Ser843残基上的磷酸化与FN有关。即使在LY294002存在的情况下，这些丝氨酸/酪氨酸残基在FN包被的表面仍被磷酸化。相比之下，粘着斑蛋白桩蛋白在Tyr31处未被FN磷酸化。总之，FN对SCLC细胞的刺激导致活力增强和细胞骨架功能改变，这部分是通过PI3-K途径介导的。
