Department of Radiation Oncology and Molecular Radiation Sciences, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
The Russell H. Morgan Department of Radiology and Radiological Science, Division of Cancer Imaging Research, Johns Hopkins University School of Medicine, Baltimore, MD, USA; Department of Oncology, Sidney Kimmel Comprehensive Cancer Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA; In Vivo Cellular and Molecular Imaging Center, Johns Hopkins University School of Medicine, Baltimore, MD, USA.
Neoplasia. 2015 Jan;17(1):16-31. doi: 10.1016/j.neo.2014.10.009.
The TWIST1 gene has diverse roles in development and pathologic diseases such as cancer. TWIST1 is a dimeric basic helix-loop-helix (bHLH) transcription factor existing as TWIST1-TWIST1 or TWIST1-E12/47. TWIST1 partner choice and DNA binding can be influenced during development by phosphorylation of Thr125 and Ser127 of the Thr-Gln-Ser (TQS) motif within the bHLH of TWIST1. The significance of these TWIST1 phosphorylation sites for metastasis is unknown. We created stable isogenic prostate cancer cell lines overexpressing TWIST1 wild-type, phospho-mutants, and tethered versions. We assessed these isogenic lines using assays that mimic stages of cancer metastasis. In vitro assays suggested the phospho-mimetic Twist1-DQD mutation could confer cellular properties associated with pro-metastatic behavior. The hypo-phosphorylation mimic Twist1-AQA mutation displayed reduced pro-metastatic activity compared to wild-type TWIST1 in vitro, suggesting that phosphorylation of the TWIST1 TQS motif was necessary for pro-metastatic functions. In vivo analysis demonstrates that the Twist1-AQA mutation exhibits reduced capacity to contribute to metastasis, whereas the expression of the Twist1-DQD mutation exhibits proficient metastatic potential. Tethered TWIST1-E12 heterodimers phenocopied the Twist1-DQD mutation for many in vitro assays, suggesting that TWIST1 phosphorylation may result in heterodimerization in prostate cancer cells. Lastly, the dual phosphatidylinositide 3-kinase (PI3K)-mammalian target of rapamycin (mTOR) inhibitor BEZ235 strongly attenuated TWIST1-induced migration that was dependent on the TQS motif. TWIST1 TQS phosphorylation state determines the intensity of TWIST1-induced pro-metastatic ability in prostate cancer cells, which may be partly explained mechanistically by TWIST1 dimeric partner choice.
TWIST1 基因在发育和病理性疾病（如癌症）中具有多种作用。TWIST1 是一种二聚体碱性螺旋-环-螺旋（bHLH）转录因子，存在 TWIST1-TWIST1 或 TWIST1-E12/47 两种形式。TWIST1 伴侣选择和 DNA 结合在发育过程中可受到 TWIST1 bHLH 内 Thr-Gln-Ser（TQS）模体中 Thr125 和 Ser127 的磷酸化影响。这些 TWIST1 磷酸化位点对转移的意义尚不清楚。我们构建了过表达 TWIST1 野生型、磷酸化突变体和锚定形式的稳定同基因前列腺癌细胞系。我们使用模拟癌症转移各阶段的检测方法评估这些同基因系。体外检测表明，磷酸化模拟突变体 Twist1-DQD 可能赋予与促转移行为相关的细胞特性。与野生型 TWIST1 相比，低磷酸化模拟突变体 Twist1-AQA 在体外显示出降低的促转移活性，表明 TWIST1 TQS 模体的磷酸化对于促转移功能是必需的。体内分析表明，Twist1-AQA 突变体的转移能力降低，而 Twist1-DQD 突变体的表达则具有较强的转移潜能。TWIST1-E12 异二聚体的表达在许多体外检测中模拟了 Twist1-DQD 突变，表明 TWIST1 磷酸化可能导致前列腺癌细胞中的异二聚化。最后，双重磷脂酰肌醇 3-激酶（PI3K）-雷帕霉素靶蛋白（mTOR）抑制剂 BEZ235 强烈抑制了依赖于 TQS 模体的 TWIST1 诱导的迁移。TWIST1 TQS 磷酸化状态决定了 TWIST1 诱导的前列腺癌细胞促转移能力的强度，这在机制上部分可以通过 TWIST1 二聚体伴侣选择来解释。
