Unitat de Farmacologia i Farmacognòsia, Facultat de Farmàcia, Centros de Investigación Biomédica en Red Enfermedades Neurodegenerativas (CIBERNED), Institut de Biomedicina (IBUB), Universitat de Barcelona, Nucli Universitari de Pedralbes, 08028 Barcelona, Spain.
Pharmacol Res. 2012 Jan;65(1):66-73. doi: 10.1016/j.phrs.2011.08.006. Epub 2011 Aug 22.
In the present study, we evaluated the effects of roscovitine (Rosco) and flavopiridol (Flavo), both of which are classified as cyclin-dependent kinase (CDK) inhibitors, on apoptosis induced by the inhibition of PI3K/AKT pathway in cerebellar granule neurons (CGNs). Our results demonstrate that both CDK inhibitors prevented apoptosis induced by LY294002 (LY), as also occurs with SB415286 (SB4), a selective GSK3β inhibitor. Our findings also indicate that these CDK inhibitors inhibit GSK3β, representing a potential pharmacological mechanism involved in their neuroprotective properties. Thus, the increased activity of GSK3β induced by LY294002 and detected by dephosphorylation at Ser9 was prevented by both compounds. Likewise, GSK3β activity was measured by a radioactivity assay, revealing that CDK inhibitors and SB415286 prevented the increase in GSK3β activity induced by PI3K inhibition. In addition, we analysed c-Jun, which is also a mediator of PI3K inhibition-induced apoptosis. However, neither of the CDK inhibitors nor SB415286 prevented the increase in c-Jun phosphorylation induced by PI3K inhibition. Therefore, our data identify GSK3β as a crucial mediator of CGN apoptosis induced by PI3K inhibition and indicate that the antiapoptotic effects of CDKs are mediated by the inhibition of this pharmacological target.
在本研究中，我们评估了罗司维汀（Rosco）和 flavopiridol（Flavo）对小脑颗粒神经元（CGNs）中 PI3K/AKT 通路抑制诱导的细胞凋亡的影响，这两种药物均属于细胞周期蛋白依赖性激酶（CDK）抑制剂。我们的结果表明，两种 CDK 抑制剂均可防止 LY294002（LY）诱导的细胞凋亡，这与选择性 GSK3β抑制剂 SB415286（SB4）的作用相同。我们的研究结果还表明，这些 CDK 抑制剂抑制 GSK3β，这代表了其神经保护特性的潜在药理机制。因此，LY294002 诱导的 GSK3β活性增加（通过 Ser9 去磷酸化检测到）被这两种化合物所抑制。同样，通过放射性测定法测量 GSK3β 活性，结果表明 CDK 抑制剂和 SB415286 可防止 PI3K 抑制诱导的 GSK3β活性增加。此外，我们还分析了 c-Jun，它也是 PI3K 抑制诱导细胞凋亡的介质。然而，PI3K 抑制诱导的 c-Jun 磷酸化增加既不受 CDK 抑制剂的影响，也不受 SB415286 的影响。因此，我们的数据确定 GSK3β 是 PI3K 抑制诱导的 CGN 凋亡的关键介质，并表明 CDK 的抗凋亡作用是通过抑制该药理靶标介导的。
