Bailly M, Condeelis J S, Segall J E
Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461, USA.
Microsc Res Tech. 1998 Dec 1;43(5):433-43. doi: 10.1002/(SICI)1097-0029(19981201)43:5<433::AID-JEMT9>3.0.CO;2-2.
The mammary adenocarcinoma cell line MTLn3 is chemotactic towards epidermal growth factor (EGF), and this induced motility is thought to promote breast cancer invasion and metastasis. Stimulation of MTLn3 cells with EGF results in the extension of a flat, thin structure filled with filamentous actin and termed a lamellipod. Lamellipod extension is dependent on actin polymerization and is localized to the border of adherent cells. The structure of EGF-stimulated lamellipods in MTLn3 cells is well suited to analysis of chemoattractant-stimulated protrusion. Actin polymerization occurs within 200 nm of the extending edge of the lamellipod. Although extension of the lamellipod is not dependent upon interaction with the substratum, stabilization of the extended lamellipod is dependent on an adhesive substratum. Dorsal ruffling is suppressed during lamellipod extension. Tyrosine phosphorylation is reduced in preexisting focal contacts compared to new contacts induced by EGF stimulation. The coordination of turnover of focal contacts with lamellipod extension is proposed to result in polarized cell motility in response to gradients of chemoattractants.
乳腺腺癌细胞系MTLn3对表皮生长因子（EGF）具有趋化性，这种诱导的运动性被认为会促进乳腺癌的侵袭和转移。用EGF刺激MTLn3细胞会导致一种扁平、薄的结构延伸，该结构充满丝状肌动蛋白，被称为片状伪足。片状伪足的延伸依赖于肌动蛋白聚合，且定位于贴壁细胞的边界。MTLn3细胞中EGF刺激的片状伪足结构非常适合对趋化因子刺激的突起进行分析。肌动蛋白聚合发生在片状伪足延伸边缘200纳米范围内。虽然片状伪足的延伸不依赖于与基质的相互作用，但延伸的片状伪足的稳定依赖于黏附性基质。在片状伪足延伸过程中背侧波动受到抑制。与EGF刺激诱导的新黏着斑相比，先前存在的黏着斑中的酪氨酸磷酸化减少。黏着斑周转与片状伪足延伸的协调作用被认为会导致细胞对趋化因子梯度产生极化运动。
