Trophoblast cell invasiveness and the mechanisms of its regulation

滋养层细胞侵袭力及其调控机制

• 批准号: 09470360
• 负责人: KURACHI Hirohisa
• 金额: $ 8.51万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1999
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09470360/
• 关键词: trophoblast; integrin; placenta; invasion; epidermal growth factor; chemokinasis; 細胞外マトリックス; プロモーター; 転写制御; MAPキナーゼ系; JAK-STAT系; 増殖因子; サイトカイン

Trophoblast, an important component of mammalian placenta has a unique biological features. Particularly, during the first trimester of pregnancy, trophoblasts start invading into uterine wall as far as uterine spinal arteries. Interestingly, this invasive behavior is strictly regulated so that the invasion would not go beyond uterine vessels. Recently, particular members of integrins have been described to be expressed on trophoblast. Evidence has been accumulated that these integrins play an essential role for the regulation of the invasive behavior described above. It has been shown that two main mechanisms are involved in cell-to-cell and cell-to extracellular matrix (ECM) interactions : interaction via ligand receptor binding, and comunication by soluble growth factors or cytokines such as epidermal growth factor (EGF), interleukin-6 (IL-6), transforming growth factor-beta (TGF-β), or leukemia inhibitory factor (LIF).In this study, utilizing human BeWo choriocarcinoma cells, we ex … More amined whether epidermal growth factor influences integrin expression on the surface of BeWo cells. Among integrin molecules examined by flow cytometry, α2 integrin expression was increased most effectively at 12, 24 and 48 hours after stimulation of 10 nM EGF. This increase concurrently occurred along the increase of human choriogenic gonadotropin (hCG) secretion, which indicates functional differentiation of trophoblasts. In addition, the α2 integrin transcripts were induced in response to EGF as early as 3 hours after addition.Combined with previous knowledge, we speculated that the increase of α2 integrin play a role in the invasion activity into endometrium. An invasion assay indicated that EGF increased invasion activity of BeWo cells at biological concentration. Antibody against α2 integrin suppressed the invasion activity more effectively on EGF-treated cells than untreated cells, which may indicate that the increase of cell surface α2 integrin may contribute to augmented invasiveness into Matrigel. Furthermore, we examined the effects of EGF on BeWo cell adhesion on collagen and chemokinasis by EGF by adhesion assay and Boyden Chamber assay, respectively. EGF did not alter the adhesion of BeWo cells to collagen matrix. On the other hand, EGF augmented chemokinasis activity of BeWo cells in dose-dependant manner. Noteworthy was that the increase of chemokinasis activity was suppressed by antibody against α2 integrin antibody more effectively when the cells were treated with EGF reimniscently to the invasion assay results. Given these results, we concluded that i) α2 integrin is an inducible molecule by EGF. ii) the increase of α2 integrin by EGF accounts in part for the augmentation of invasiveness of BeWo cells, presumably due to increase of chemokinasis activity. Less

滋养层细胞是哺乳动物胎盘的重要组成部分，具有独特的生物学特性。特别是，在怀孕的前三个月，滋养细胞开始侵入子宫壁，直到子宫脊髓动脉。有趣的是，这种侵袭行为受到了严格的监管，因此侵袭不会超出子宫血管。最近，整合素的特定成员被描述为在滋养层细胞上表达。越来越多的证据表明，这些整合素在上述侵袭行为的调节中起着至关重要的作用。细胞与细胞之间和细胞与细胞外基质之间的相互作用主要有两种机制：通过配体受体结合的相互作用，以及通过可溶性生长因子或细胞因子如表皮生长因子、白介素6、转化生长因子-ββ、白血病抑制因子等的相互作用。更多的是关于表皮生长因子是否影响BeWo细胞表面整合素的表达。在流式细胞仪检测的整合素分子中，α2整合素的表达在10 nM表皮生长因子刺激后12、24和48h最明显。这种增加与人绒毛膜促性腺激素(HCG)分泌的增加同时发生，这表明滋养层细胞的功能分化。此外，α2整合素的转录产物在加入表皮生长因子后3h即可被诱导，结合已有的研究结果，我们推测α2整合素的增加在子宫内膜的侵袭活动中起一定作用。侵袭实验表明，在生物浓度范围内，EGF可增强BeWo细胞的侵袭活性。抗α-2整合素抗体能更有效地抑制α-2整合素对细胞的侵袭活性，提示细胞表面整合素的增加可能是细胞侵袭力增强的原因之一。此外，我们通过黏附实验和Boyden小室实验分别检测了EGF对BeWo细胞与胶原黏附和趋化作用的影响。EGF不改变BeWo细胞与胶原基质的黏附。另一方面，EGF以剂量依赖的方式增强BeWo细胞的趋化活性。值得注意的是，当α-2整合素抗体与侵袭实验结果一致时，能更有效地抑制趋化活性的增加。根据这些结果，我们得出结论：1)α-2整合素是一种可被表皮生长因子诱导的分子。2)表皮生长因子上调α-2整合素的表达可能是BEWO细胞侵袭力增强的部分原因，可能是由于趋化活性增强所致。较少