Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Trivandrum 695014, India.
Graduate Degree Program, Manipal Academy of Higher Education, Manipal, Udupi 576104, India.
Cells. 2022 Jul 25;11(15):2290. doi: 10.3390/cells11152290.
Overexpression and hyperactivation of the serine/threonine protein kinase B (AKT) pathway is one of the most common cellular events in breast cancer progression. However, the nature of AKT1-specific genome-wide transcriptomic alterations in breast cancer cells and breast cancer remains unknown to this point. Here, we delineate the impact of selective AKT1 knock down using gene-specific siRNAs or inhibiting the AKT activity with a pan-AKT inhibitor VIII on the nature of transcriptomic changes in breast cancer cells using the genome-wide RNA-sequencing analysis. We found that changes in the cellular levels of AKT1 lead to changes in the levels of a set of differentially expressed genes and, in turn, imply resulting AKT1 cellular functions. In addition to an expected positive relationship between the status of AKT1 and co-expressed cellular genes, our study unexpectedly discovered an inherent role of AKT1 in inhibiting the expression of a subset of genes in both unstimulated and growth factor stimulated breast cancer cells. We found that depletion of AKT1 leads to upregulation of a subset of genes-many of which are also found to be downregulated in breast tumors with elevated high AKT1 as well as upregulated in breast tumors with no detectable AKT expression. Representative experimental validation studies in two breast cancer cell lines showed a reasonable concurrence between the expression data from the RNA-sequencing and qRT-PCR or data from ex vivo inhibition of AKT1 activity in cancer patient-derived cells. In brief, findings presented here provide a resource for further understanding of AKT1-dependent modulation of gene expression in breast cancer cells and broaden the scope and significance of AKT1 targets and their functions.
丝氨酸/苏氨酸蛋白激酶 B（AKT）途径的过度表达和超激活是乳腺癌进展中最常见的细胞事件之一。然而，到目前为止，乳腺癌中 AKT1 特异性全基因组转录组改变的性质仍然未知。在这里，我们使用基因特异性 siRNA 或使用泛 AKT 抑制剂 VIII 抑制 AKT 活性来描绘选择性 AKT1 敲低对乳腺癌细胞转录组变化的影响，使用全基因组 RNA-seq 分析。我们发现 AKT1 细胞水平的变化导致一组差异表达基因水平的变化，进而暗示 AKT1 细胞功能的变化。除了 AKT1 的状态与共表达细胞基因之间的预期正相关关系外，我们的研究还意外地发现 AKT1 在抑制未刺激和生长因子刺激的乳腺癌细胞中一组基因的表达方面具有内在作用。我们发现 AKT1 的耗竭导致一组基因的上调，其中许多基因在 AKT1 水平升高的乳腺癌肿瘤中也下调，在 AKT 表达不可检测的乳腺癌肿瘤中上调。在两种乳腺癌细胞系中的代表性实验验证研究表明，RNA-seq 和 qRT-PCR 的表达数据之间存在合理的一致性，或者癌症患者来源细胞中 AKT1 活性的体外抑制数据之间存在一致性。简而言之，这里提出的研究结果为进一步了解 AKT1 依赖性调节乳腺癌细胞中基因表达提供了资源，并拓宽了 AKT1 靶标及其功能的范围和意义。
