Pillinger Genevra, Loughran Niamh V, Piddock Rachel E, Shafat Manar S, Zaitseva Lyubov, Abdul-Aziz Amina, Lawes Matthew J, Bowles Kristian M, Rushworth Stuart A
Department of Molecular Haematology, Norwich Medical School, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, United Kingdom.
Department of Haematology, Norfolk and Norwich University Hospitals NHS Trust, Norwich, NR4 7UY, United Kingdom.
Oncotarget. 2016 Jun 28;7(26):39784-39795. doi: 10.18632/oncotarget.9289.
Phosphoinositide-3-kinase (PI3K) is an enzyme group, known to regulate key survival pathways in acute myeloid leukaemia (AML). It generates phosphatidylinositol-3,4,5-triphosphate, which provides a membrane docking site for protein kinaseB activation. PI3K catalytic p110 subunits are divided into 4 isoforms; α,β,δ and γ. The PI3Kδ isoform is always expressed in AML cells, whereas the frequency of PI3Kγ expression is highly variable. The functions of these individual catalytic enzymes have not been fully resolved in AML, therefore using the PI3K p110δ and p110γ-targeted inhibitor IPI-145 (duvelisib) and specific p110δ and p110γ shRNA, we analysed the role of these two p110 subunits in human AML blast survival. The results show that PI3Kδ and PI3Kγ inhibition with IPI-145 has anti-proliferative activity in primary AML cells by inhibiting the activity of AKT and MAPK. Pre-treatment of AML cells with IPI-145 inhibits both adhesion and migration of AML blasts to bone marrow stromal cells. Using shRNA targeted to the individual isoforms we demonstrated that p110δ-knockdown had a more significant anti-proliferative effect on AML cells, whereas targeting p110γ-knockdown significantly inhibited AML migration. The results demonstrate that targeting both PI3Kδ and PI3Kγ to inhibit AML-BMSC interactions provides a biologic rationale for the pre-clinical evaluation of IPI-145 in AML.
磷脂酰肌醇-3-激酶(PI3K)是一组酶,已知其可调节急性髓系白血病(AML)中的关键生存途径。它生成磷脂酰肌醇-3,4,5-三磷酸,为蛋白激酶B的激活提供膜停靠位点。PI3K催化性p110亚基分为4种异构体:α、β、δ和γ。PI3Kδ异构体在AML细胞中总是表达,而PI3Kγ表达的频率变化很大。这些单个催化酶在AML中的功能尚未完全明确,因此我们使用PI3K p110δ和p110γ靶向抑制剂IPI-145(度维利西布)以及特异性p110δ和p110γ短发夹RNA(shRNA),分析了这两个p110亚基在人AML原始细胞存活中的作用。结果表明,用IPI-145抑制PI3Kδ和PI3Kγ对原代AML细胞具有抗增殖活性,其通过抑制AKT和MAPK的活性来实现。用IPI-145预处理AML细胞可抑制AML原始细胞与骨髓基质细胞的黏附和迁移。使用针对单个异构体的shRNA,我们证明敲低p110δ对AML细胞具有更显著的抗增殖作用,而靶向敲低p110γ则显著抑制AML的迁移。结果表明,靶向PI3Kδ和PI3Kγ以抑制AML-骨髓间充质干细胞(BMSC)相互作用为IPI-145在AML中的临床前评估提供了生物学依据。