信号转导子和转录激活子 5b（STAT5b）在β1 整联蛋白介导的人乳腺癌细胞迁移中的新作用。

A novel role for signal transducer and activator of transcription 5b (STAT5b) in beta1-integrin-mediated human breast cancer cell migration.

机构信息

Department of Microbiology, University of Virginia, 1300 Jefferson Park Avenue, Charlottesville, VA 22908, USA.

出版信息

Breast Cancer Res. 2009;11(4):R52. doi: 10.1186/bcr2341. Epub 2009 Jul 24.

INTRODUCTION

Signal transducer and activator of transcription (STAT) 5b is a transcription factor involved in pro-proliferative and pro-survival signaling in a number of solid tumors, including breast cancer. The contribution of STAT5b to breast cancer cell motility has not been explored. This work aims to elucidate the role of STAT5b in breast cancer cell migration.

METHODS

STAT5b was knocked down by using siRNA in two aggressive, highly migratory breast cancer cell lines (BT-549 and MDA-MB-231), and transwell migration assays were performed to determine the importance of STAT5b for their migration. Knockdown-rescue experiments were used to validate the specificity of STAT5b knockdown and to determine which regions/functions of STAT5b are necessary for its role in migration. Live-cell imaging of wound healing and spreading was carried out to examine cell morphology and motility after STAT5b knockdown.

RESULTS

Knockdown of STAT5b, but not STAT5a, inhibited migration of BT-549 and MDA-MB-231 breast cancer cells to serum by 60% to 80%, and inhibited migration equally over a range of serum concentrations (0.1% to 10% serum). Migratory inhibition upon STAT5b knockdown could be rescued by reintroduction of wild-type STAT5b, as well as Y699F- and dominant-negative STAT5b mutants, but not an SH2 domain defective R618K-STAT5b mutant. beta1- integrin-mediated migration of breast cancer cells to fibronectin was inhibited with STAT5b knockdown, and loss of STAT5b correlated with loss of directional migration and formation of multiple, highly contractile protrusions upon attachment to fibronectin.

CONCLUSIONS

The data presented here demonstrate that STAT5b is integral to breast cancer cell migration and identify a novel, SH2-dependent function of STAT5b in regulating beta1-integrin-mediated migration of highly aggressive breast cancer cells.

简介

信号转导子和转录激活子（STAT）5b 是一种转录因子，涉及多种实体瘤中的促增殖和抗细胞凋亡信号转导，包括乳腺癌。STAT5b 对乳腺癌细胞迁移的贡献尚未得到探索。本研究旨在阐明 STAT5b 在乳腺癌细胞迁移中的作用。

方法

使用 siRNA 在两种侵袭性、高迁移性乳腺癌细胞系（BT-549 和 MDA-MB-231）中敲低 STAT5b，并进行 Transwell 迁移实验以确定 STAT5b 对其迁移的重要性。敲低挽救实验用于验证 STAT5b 敲低的特异性，并确定 STAT5b 的哪些区域/功能对于其在迁移中的作用是必需的。进行活细胞划痕愈合和扩散实验以检查 STAT5b 敲低后细胞形态和运动性。

结果

STAT5b 的敲低而非 STAT5a 的敲低抑制了 BT-549 和 MDA-MB-231 乳腺癌细胞向血清中的迁移，抑制率为 60%至 80%，并且在 0.1%至 10%血清浓度范围内的迁移抑制率相当。STAT5b 敲低后，通过重新引入野生型 STAT5b、Y699F 和显性失活 STAT5b 突变体，但不是 SH2 结构域缺陷的 R618K-STAT5b 突变体，可以挽救迁移抑制。乳腺癌细胞向纤维连接蛋白的 beta1-整合素介导的迁移被 STAT5b 敲低所抑制，并且 STAT5b 的缺失与定向迁移的丧失以及在附着于纤维连接蛋白时形成多个高度收缩的突起相关。