Department of Molecular Cell Biology, Center for Molecular Biomedicine, Jena University Hospital, Hans-Knöll-Strasse 2, Jena 07745, Germany.
J Cancer Res Clin Oncol. 2010 Dec;136(12):1881-90. doi: 10.1007/s00432-010-0847-2. Epub 2010 Mar 12.
This work employs pharmacological targeting of phosphoinositide 3-kinases (PI3K) in selected neuroblastoma (NB) tumors with the inhibitor AS605240, which has been shown to express low toxicity and relative specificity for the PI3K species γ.
The expression pattern of PI3K isoforms in 7 NB cell lines and 14 tumor patient samples was determined by Western blotting and immunocytochemistry. The effect of AS605240 on the growth of four selected tumor cell lines was assessed. Two cell lines exhibiting (SK-N-LO) or lacking (SK-N-AS) PI3Kγ expression were chosen for further in vitro analysis, which involved propidium iodide (PI)-based cell cycle staining, terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL-staining) of apoptotic cells and analysis of PI3K/Akt-related signaling pathways via Western blotting and translocation experiments. The action of AS605240 in vivo was addressed by xenograft experiments in severe combined immunodeficiency (SCID) mice, thereby comparing SK-N-LO and SK-N-AS derived tumors. Apoptosis induced in SK-N-LO tumors was shown by immunohistochemical TUNEL-staining.
Significant expression of PI3Kγ in neuroblastoma patient biopsies and tumor cell lines was detected. AS605240 induced apoptosis in NB cell lines proportional to this expression and suppressed growth of PI3Kγ positive, but not negative, tumors in a xenograft mouse model. No adverse effects of the inhibitor treatment were observed.
Our observations hint to an oncogenic function of PI3Kγ in distinct neuroblastoma entities and reveal PI3K targeting by AS605240 as a promising molecular therapy of these tumors.
本研究采用磷脂酰肌醇 3-激酶（PI3K）抑制剂 AS605240 对特定神经母细胞瘤（NB）肿瘤进行药理学靶向治疗，该抑制剂已被证明对 PI3K 同工型γ具有低毒性和相对特异性。
通过 Western blot 和免疫细胞化学检测 7 种 NB 细胞系和 14 种肿瘤患者样本中 PI3K 同工型的表达模式。评估 AS605240 对四种选定肿瘤细胞系生长的影响。选择两个表达（SK-N-LO）或缺乏（SK-N-AS）PI3Kγ的细胞系进行进一步的体外分析，包括碘化丙啶（PI）细胞周期染色、凋亡细胞末端脱氧核苷酸转移酶介导的 dUTP-生物素 nick 末端标记（TUNEL 染色）以及通过 Western blot 和转位实验分析 PI3K/Akt 相关信号通路。通过在严重联合免疫缺陷（SCID）小鼠中进行异种移植实验来研究 AS605240 的体内作用，从而比较 SK-N-LO 和 SK-N-AS 衍生的肿瘤。通过免疫组化 TUNEL 染色显示 SK-N-LO 肿瘤中诱导的凋亡。
在神经母细胞瘤患者活检和肿瘤细胞系中检测到 PI3Kγ 的显著表达。AS605240 诱导 NB 细胞系的凋亡与这种表达成正比，并在异种移植小鼠模型中抑制 PI3Kγ 阳性但不是阴性肿瘤的生长。未观察到抑制剂治疗的不良反应。
我们的观察结果提示 PI3Kγ 在某些神经母细胞瘤实体中具有致癌功能，并揭示 AS605240 对 PI3K 的靶向作用是这些肿瘤有前途的分子治疗方法。
