Lymphoma Group, Molecular Pathology Programme, Spanish National Cancer Research Centre (CNIO), Madrid, Spain.
Haematologica. 2013 Jan;98(1):57-64. doi: 10.3324/haematol.2012.068510. Epub 2012 Jul 16.
Peripheral T-cell lymphomas are very aggressive hematologic malignancies for which there is no targeted therapy. New, rational approaches are necessary to improve the very poor outcome in these patients. Phosphatidylinositol-3-kinase is one of the most important pathways in cell survival and proliferation. We hypothesized that phosphatidylinositol-3-kinase inhibitors could be rationally selected drugs for treating peripheral T-cell lymphomas. Several phosphatidylinositol-3-kinase isoforms were inhibited genetically (using small interfering RNA) and pharmacologically (with CAL-101 and GDC-0941 compounds) in a panel of six peripheral and cutaneous T-cell lymphoma cell lines. Cell viability was measured by intracellular ATP content; apoptosis and cell cycle changes were checked by flow cytometry. Pharmacodynamic biomarkers were assessed by western blot. The PIK3CD gene, which encodes the δ isoform of phosphatidylinositol-3-kinase, was overexpressed in cell lines and primary samples, and correlated with survival pathways. However, neither genetic nor specific pharmacological inhibition of phosphatidylinositol-3-kinase δ affected cell survival. In contrast, the pan-phosphatidylinositol-3-kinase inhibitor GDC-0941 arrested all T-cell lymphoma cell lines in the G1 phase and induced apoptosis in a subset of them. We identified phospho-GSK3β and phospho-p70S6K as potential biomarkers of phosphatidylinositol-3-kinase inhibitors. Interestingly, an increase in ERK phosphorylation was observed in some GDC -0941-treated T-cell lymphoma cell lines, suggesting the presence of a combination of phosphatidylinositol-3-kinase and MEK inhibitors. A highly synergistic effect was found between the two inhibitors, with the combination enhancing cell cycle arrest at G0/G1 in all T-cell lymphoma cell lines, and reducing cell viability in primary tumor T cells ex vivo. These results suggest that the combined treatment of pan-phosphatidylinositol-3-kinase + MEK inhibitors could be more effective than single phosphatidylinositol-3-kinase inhibitor treatment, and therefore, that this combination could be of therapeutic value for treating peripheral and cutaneous T-cell lymphomas.
外周 T 细胞淋巴瘤是一种非常侵袭性的血液恶性肿瘤，目前尚无靶向治疗方法。为了改善这些患者的预后极差的情况，需要新的、合理的方法。磷脂酰肌醇 3-激酶是细胞存活和增殖最重要的途径之一。我们假设磷脂酰肌醇 3-激酶抑制剂可以作为治疗外周 T 细胞淋巴瘤的合理选择药物。我们在一组六种外周和皮肤 T 细胞淋巴瘤细胞系中，通过遗传（使用小干扰 RNA）和药理学（使用 CAL-101 和 GDC-0941 化合物）抑制了几种磷脂酰肌醇 3-激酶同工酶。通过细胞内 ATP 含量来测量细胞活力；通过流式细胞术检查细胞凋亡和细胞周期变化。通过 Western blot 评估药效学生物标志物。PIK3CD 基因，编码磷脂酰肌醇 3-激酶的 δ 同工酶，在外周和皮肤 T 细胞淋巴瘤细胞系和原代样本中过表达，并与生存途径相关。然而，无论是遗传抑制还是特定的磷脂酰肌醇 3-激酶 δ 的药理学抑制都不会影响细胞存活。相比之下，pan-phosphatidylinositol-3-kinase 抑制剂 GDC-0941 使所有 T 细胞淋巴瘤细胞系停滞在 G1 期，并诱导其中一部分细胞凋亡。我们鉴定出磷酸化-GSK3β 和磷酸化-p70S6K 作为磷脂酰肌醇 3-激酶抑制剂的潜在生物标志物。有趣的是，在一些用 GDC-0941 处理的 T 细胞淋巴瘤细胞系中观察到 ERK 磷酸化增加，表明存在磷脂酰肌醇 3-激酶和 MEK 抑制剂的组合。两种抑制剂之间存在高度协同作用，联合使用可增强所有 T 细胞淋巴瘤细胞系在 G0/G1 期的细胞周期阻滞，并减少体外原代肿瘤 T 细胞的细胞活力。这些结果表明，pan-phosphatidylinositol-3-kinase + MEK 抑制剂的联合治疗可能比单一磷脂酰肌醇 3-激酶抑制剂治疗更有效，因此，这种联合治疗可能对治疗外周和皮肤 T 细胞淋巴瘤具有治疗价值。
