D'Alimonte Iolanda, Nargi Eleonora, Zuccarini Mariachiara, Lanuti Paola, Di Iorio Patrizia, Giuliani Patricia, Ricci-Vitiani Lucia, Pallini Roberto, Caciagli Francesco, Ciccarelli Renata
Department of Medical, Oral and Biotechnology Sciences, University of Chieti-Pescara, via dei Vestini 29, 66100, Chieti, Italy.
Purinergic Signal. 2015 Sep;11(3):331-46. doi: 10.1007/s11302-015-9454-7. Epub 2015 May 15.
Glioblastoma multiforme (GBM), the most common and aggressive brain tumor in humans, comprises a population of stem-like cells (GSCs) that are currently investigated as potential target for GBM therapy. Here, we used GSCs isolated from three different GBM surgical specimens to examine the antitumor activity of purines. Cultured GSCs expressed either metabotropic adenosine P1 and ATP P2Y receptors or ionotropic P2X7 receptors. GSC exposure for 48 h to 10-150 μM ATP, P2R ligand, or to ADPβS or MRS2365, P2Y1R agonists, enhanced cell expansion. This effect was counteracted by the PY1R antagonist MRS2500. In contrast, 48-h treatment with higher doses of ATP or UTP, which binds to P2Y2/4R, or 2'(3')-O-(4-benzoylbenzoyl)-ATP (Bz-ATP), P2X7R agonist, decreased GSC proliferation. Such a reduction was due to apoptotic or necrotic cell death but mostly to growth arrest. Accordingly, cell regrowth and secondary neurosphere formation were observed 2 weeks after the end of treatment. Suramin, nonselective P2R antagonist, MRS1220 or AZ11645373, selective A3R or P2X7R antagonists, respectively, counteracted ATP antiproliferative effects. AZ11645373 also abolished the inhibitory effect of Bz-ATP low doses on GSC growth. These findings provide important clues on the anticancer potential of ligands for A3R, P2Y1R, and P2X7R, which are involved in the GSC growth control. Interestingly, ATP and BzATP potentiated the cytotoxicity of temozolomide (TMZ), currently used for GBM therapy, enabling it to cause a greater and long-lasting inhibitory effect on GSC duplication when readded to cells previously treated with purine nucleotides plus TMZ. These are the first findings identifying purine nucleotides as able to enhance TMZ antitumor efficacy and might have an immediate translational impact.
多形性胶质母细胞瘤（GBM）是人类最常见且侵袭性最强的脑肿瘤，其中包含一群干细胞样细胞（GSCs），目前它们正作为GBM治疗的潜在靶点进行研究。在此，我们使用从三个不同GBM手术标本中分离出的GSCs来检测嘌呤的抗肿瘤活性。培养的GSCs表达代谢型腺苷P1受体和ATP P2Y受体或离子型P2X7受体。将GSCs暴露于10 - 150μM的ATP（P2R配体）、ADPβS或MRS2365（P2Y1R激动剂）48小时，可增强细胞增殖。这种效应被PY1R拮抗剂MRS2500抵消。相反，用更高剂量的ATP或UTP（与P2Y2/4R结合）或2'(3')-O-(4-苯甲酰苯甲酰)-ATP（Bz-ATP，P2X7R激动剂）处理48小时，会降低GSC增殖。这种减少是由于凋亡或坏死性细胞死亡，但主要是由于生长停滞。因此，在治疗结束2周后观察到细胞再生长和次级神经球形成。苏拉明（非选择性P2R拮抗剂）、MRS1220或AZ11645373（分别为选择性A3R或P2X7R拮抗剂）可抵消ATP的抗增殖作用。AZ11645373还消除了低剂量Bz-ATP对GSC生长的抑制作用。这些发现为参与GSC生长控制的A3R、P2Y1R和P2X7R配体的抗癌潜力提供了重要线索。有趣的是，ATP和BzATP增强了目前用于GBM治疗的替莫唑胺（TMZ）的细胞毒性，当重新添加到先前用嘌呤核苷酸加TMZ处理过的细胞中时，使其能够对GSC复制产生更大且持久的抑制作用。这些是首次发现嘌呤核苷酸能够增强TMZ抗肿瘤疗效的研究结果，可能会立即产生转化影响。
