Centre Scientifique de Monaco, Department of Medical Biology, 8 Quai Antoine Ier, Monaco, Principality of Monaco.
UCA, Université Côte d'Azur, Nice-Sophia-Antipolis, Institute for Research on Cancer and Aging of Nice, CNRS-UMR 7284-Inserm U1081, Nice, France.
BMC Cancer. 2018 Mar 5;18(1):249. doi: 10.1186/s12885-018-4169-0.
In mammals, the AKT/PKB protein kinase family comprises three members (AKT1-3). PI3-Kinase (PI3K), a key oncogene involved in a wide variety of cancers, drives AKT activity. Constitutive activation of the PI3K/AKT pathway has been associated with tumorigenic properties including uncontrolled cell proliferation and survival, angiogenesis, promotion of cellular motility, invasiveness and metastasis. However, AKT1 activity has also been recently shown to repress the invasive properties of breast cancer cells in specific contexts.
This study used both pharmacological and shRNA approaches to inhibit AKT function, microscopy to characterize the cellular morphology, 3D spheroid models to assess migratory and invasive cellular capacities and a phenotypic screening approach based on electrical properties of the cells.
Here we demonstrate that the alternative action of AKT1 on invasive properties of breast cancers can be extended to head and neck carcinomas, which exhibit constitutive activation of the PI3K/AKT pathway. Indeed, inhibition of AKT1 function by shRNA or a specific pharmacological inhibitor resulted in cellular spreading and an invasive phenotype. A phenotypic screening approach based on cellular electrical properties corroborated microscopic observations and provides a foundation for future high-throughput screening studies. This technique further showed that the inhibition of AKT1 signaling is phenocopied by blocking the mTORC1 pathway with rapamycin.
Our study suggests that the repressive action of PI3K/AKT1 on cellular invasive properties may be a mechanism common to several cancers. Current and future studies involving AKT inhibitors must therefore consider this property to prevent metastases and consequently to improve survival.
在哺乳动物中，AKT/PKB 蛋白激酶家族由三个成员（AKT1-3）组成。PI3-激酶（PI3K）是一种参与多种癌症的关键致癌基因，可驱动 AKT 活性。PI3K/AKT 通路的组成性激活与致瘤特性相关，包括不受控制的细胞增殖和存活、血管生成、促进细胞迁移、侵袭和转移。然而，最近的研究表明，AKT1 活性在特定情况下也会抑制乳腺癌细胞的侵袭特性。
本研究使用药理学和 shRNA 方法抑制 AKT 功能，通过显微镜观察细胞形态，使用 3D 球体模型评估迁移和侵袭细胞能力，以及基于细胞电特性的表型筛选方法。
我们证明了 AKT1 对乳腺癌侵袭特性的替代作用可以扩展到头颈部癌，这些癌症表现出 PI3K/AKT 通路的组成性激活。事实上，通过 shRNA 或特异性药理学抑制剂抑制 AKT1 功能会导致细胞扩散和侵袭表型。基于细胞电特性的表型筛选方法与显微镜观察结果一致，并为未来高通量筛选研究提供了基础。该技术进一步表明，用雷帕霉素阻断 mTORC1 通路可模拟 AKT1 信号通路的抑制作用。
我们的研究表明，PI3K/AKT1 对细胞侵袭特性的抑制作用可能是几种癌症的共同机制。因此，涉及 AKT 抑制剂的当前和未来研究必须考虑到这一特性，以防止转移，从而提高生存率。
