Abstract SASH1 is an adapter and signaling protein that contains SH3 and SAM domains responsible for protein–protein interactions. SASH1 downregulation has been observed in many tumors. We examined localization of SASH1 in cultures of normal IAR-20 epithelial cells and HT-29 colorectal cancer cells using immunofluorescence staining and confocal microscopy. IAR-20 normal epithelial cells and HT-29 cells with epithelial phenotype formed stable linear adherens junctions (AJs) associated with circumferential actin bundles. In both IAR-20 and HT-29 cells, SASH1 was co-localized with zones of circumferential actin bundles and linear AJs. SASH1 was not detected in lamellipodia. IAR-20 and HT-29 cells treated with Epidermal Growth Factor underwent epithelial-mesenchymal transition (EMT). We observed significant differences in the course of EMT between IAR-20 and HT-29 cultures. IAR-20 cells underwent partial EMT acquiring migratory phenotype but retaining E-cadherin in unstable radial AJs. SASH1 was present in these contacts. Disappearance of AJs was observed in HT-29 cell undergoing a complete EMT, which also resulted in disruption of stable cell–cell adhesion. SASH1 was lost from the zones of cell–cell interaction. SASH1 depletion by means of RNA interference in IAR-20 cells led to destruction of stable linear AJs and acquisition of mesenchymal phenotype by some of the cells. These data indicate involvement of SASH1 in the maintenance of stable cell–cell adhesion.

中文翻译：

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SASH1 参与维持稳定的细胞-细胞粘附

摘要 SASH1 是一种衔接子和信号蛋白，包含负责蛋白质-蛋白质相互作用的 SH3 和 SAM 结构域。在许多肿瘤中观察到 SASH1 下调。我们使用免疫荧光染色和共聚焦显微镜检查了 SASH1 在正常 IAR-20 上皮细胞和 HT-29 结肠直肠癌细胞培养物中的定位。IAR-20 正常上皮细胞和具有上皮表型的 HT-29 细胞形成与圆周肌动蛋白束相关的稳定线性粘附连接 (AJ)。在 IAR-20 和 HT-29 细胞中，SASH1 与圆周肌动蛋白束和线性 AJ 区域共定位。在片状伪足中未检测到 SASH1。用表皮生长因子处理的 IAR-20 和 HT-29 细胞经历上皮间质转化 (EMT)。我们观察到 IAR-20 和 HT-29 培养物在 EMT 过程中的显着差异。IAR-20 细胞经历了部分 EMT 获得迁移表型，但在不稳定的径向 AJ 中保留了 E-钙粘蛋白。这些接触中存在 SASH1。在经历完全 EMT 的 HT-29 细胞中观察到 AJ 的消失，这也导致稳定的细胞 - 细胞粘附的破坏。SASH1 从细胞间相互作用的区域中丢失。在 IAR-20 细胞中通过 RNA 干扰来消耗 SASH1 导致稳定的线性 AJ 破坏和一些细胞获得间充质表型。这些数据表明 SASH1 参与维持稳定的细胞 - 细胞粘附。这些接触中存在 SASH1。在经历完全 EMT 的 HT-29 细胞中观察到 AJ 的消失，这也导致稳定的细胞 - 细胞粘附的破坏。SASH1 从细胞间相互作用的区域中丢失。在 IAR-20 细胞中通过 RNA 干扰来消耗 SASH1 导致稳定的线性 AJ 破坏和一些细胞获得间充质表型。这些数据表明 SASH1 参与维持稳定的细胞 - 细胞粘附。这些接触中存在 SASH1。在经历完全 EMT 的 HT-29 细胞中观察到 AJ 的消失，这也导致稳定的细胞 - 细胞粘附的破坏。SASH1 从细胞间相互作用的区域中丢失。在 IAR-20 细胞中通过 RNA 干扰来消耗 SASH1 导致稳定的线性 AJ 破坏和一些细胞获得间充质表型。这些数据表明 SASH1 参与维持稳定的细胞 - 细胞粘附。