Department of Cell Science, Research Institute for Frontier Medicine, Sapporo Medical University School of Medicine, South-1, West-17, Chuo-ku, Sapporo, 060-8556, Japan.
Department of Obstetrics and Gynecology, Sapporo Medical University School of Medicine, Sapporo, Japan.
Histochem Cell Biol. 2020 Aug;154(2):197-213. doi: 10.1007/s00418-020-01876-8. Epub 2020 Apr 7.
Apoptosis-stimulating p53 protein 2 (ASPP2) is an apoptosis inducer that acts via binding with p53 and epithelial polarity molecule PAR3. Lipolysis-stimulated lipoprotein receptor (LSR) is an important molecule at tricellular contacts, and loss of LSR promotes cell migration and invasion via Yes-associated protein (YAP) in human endometrial cancer cells. In the present study, to find how ASPP2 suppression promotes malignancy in human endometrial cancer, we investigated its mechanisms including the relationship with LSR. In endometriosis and endometrial cancers (G1 and G2), ASPP2 was observed as well as PAR3 and LSR in the subapical region. ASPP2 decreased in G3 endometrial cancer compared to G1. In human endometrial cancer cell line Sawano, ASPP2 was colocalized with LSR and tricellulin at tricellular contacts and binding to PAR3, LSR, and tricellulin in the confluent state. ASPP2 suppression promoted cell migration and invasion, decreased LSR expression, and induced expression of phosphorylated YAP, claudin-1, -4, and -7 as effectively as the loss of LSR. Knockdown of YAP prevented the upregulation of pYAP, cell migration and invasion induced by the ASPP2 suppression. Treatment with a specific antibody against ASPP2 downregulated ASPP2 and LSR, affected F-actin at tricellular contacts, upregulated expression of pYAP and claudin-1, and induced cell migration and invasion via YAP. In normal human endometrial epithelial cells, ASPP2 was in part colocalized with LSR at tricellular contacts and knockdown of ASPP2 or LSR induced expression of claudin-1 and claudin-4. ASPP2 suppression promoted cell invasion and migration via LSR and YAP in human endometrial cancer cells.
凋亡刺激蛋白 p53 结合蛋白 2（ASPP2）是一种凋亡诱导剂，通过与 p53 和上皮极性分子 PAR3 结合发挥作用。脂肪分解刺激脂蛋白受体（LSR）是三细胞接触处的重要分子，在人类子宫内膜癌细胞中，LSR 的丢失通过 Yes 相关蛋白（YAP）促进细胞迁移和侵袭。在本研究中，为了寻找 ASPP2 抑制如何促进人类子宫内膜癌的恶性转化，我们研究了其机制，包括与 LSR 的关系。在子宫内膜异位症和子宫内膜癌（G1 和 G2）中，在亚顶区观察到 ASPP2 以及 PAR3 和 LSR。与 G1 相比，G3 子宫内膜癌中 ASPP2 减少。在人类子宫内膜癌细胞系 Sawano 中，ASPP2 与 LSR 和三细胞连接蛋白 tricellulin 一起在三细胞连接处共定位，并在细胞汇合状态下与 PAR3、LSR 和 tricellulin 结合。ASPP2 抑制促进细胞迁移和侵袭，降低 LSR 表达，并诱导磷酸化 YAP、claudin-1、-4 和 -7 的表达，其效果与 LSR 的缺失相当。YAP 的敲低阻止了由 ASPP2 抑制引起的 pYAP、细胞迁移和侵袭的上调。针对 ASPP2 的特异性抗体处理下调了 ASPP2 和 LSR，影响了三细胞接触处的 F-肌动蛋白，上调了 pYAP 和 claudin-1 的表达，并通过 YAP 诱导细胞迁移和侵袭。在正常的人类子宫内膜上皮细胞中，ASPP2 部分与 LSR 在三细胞连接处共定位，ASPP2 或 LSR 的敲低诱导了 claudin-1 和 claudin-4 的表达。ASPP2 抑制通过 LSR 和 YAP 促进人类子宫内膜癌细胞的侵袭和迁移。
