Methuosis has been described as a distinctive form of cell death characterized by the displacement of large fluid-filled vacuoles derived from uncontrolled macropinocytosis. Its induction has been proposed as a new strategy against cancer cells. Small molecules, such as indole-based calchones, have been identified as methuosis inducers and, recently, the CK2 inhibitor CX-4945 has been shown to have a similar effect on different cell types. However, the contribution of protein kinase CK2 to methuosis signalling is still controversial. Here we show that methuosis is not related to CK2 activity since it is not affected by structurally unrelated CK2 inhibitors and genetic reduction/ablation of CK2 subunits. Interestingly, CX-5011, a CK2 inhibitor related to CX-4945, behaves as a CK2-independent methuosis inducer, four times more powerful than its parental compound and capable to promote the formation on enlarged cytosolic vacuoles at low micromolar concentrations. We show that pharmacological inhibition of the small GTPase Rac-1, its downregulation by siRNA treatment, or the over-expression of the dominant-negative mutated form of Rac-1 (Rac-1 T17N), impairs CX-5011 ability to induce methuosis. Furthermore, cell treatment with CX-5011 induces a durable activation of Rac-1 that persists for at least 24 h. Worthy of note, CX-5011 is able to promote macropinocytosis not only in mammalian cells, but also in an in-vivo zebrafish model. Based on these evidences, CX-5011 is, therefore, proposed as a potential promising compound for cancer therapies for its dual efficacy as an inhibitor of the pro-survival kinase CK2 and inducer of methuosis.

甲基化被描述为细胞死亡的一种独特形式，其特征是源自不受控制的巨胞饮作用的充满大量液体的液泡的移位。已经提出将其诱导作为针对癌细胞的新策略。小分子分子（例如基于吲哚的钙酮）已被识别为变色诱导剂，最近，CK2抑制剂CX-4945已显示出对不同细胞类型的相似作用。然而，蛋白激酶CK2对促变信号的贡献仍存在争议。在这里，我们显示出变态与CK2活性无关，因为它不受结构无关的CK2抑制剂和CK2亚基的遗传还原/消融的影响。有趣的是，与CX-4945相关的CK2抑制剂CX-5011充当了不依赖CK2的变态诱导剂，比其母体化合物强四倍，并且能够在低微摩尔浓度下促进扩大的胞质液泡的形成。我们显示小GTPase Rac-1的药理抑制作用，通过siRNA处理对其的下调或Rac-1（Rac-1 T17N）的显性负突变形式的过表达会损害CX-5011诱导变色的能力。 。此外，用CX-5011进行细胞处理可诱导Rac-1持久活化，持续至少24小时。值得注意的是，CX-5011不仅能够促进哺乳动物细胞中的巨胞饮作用，而且还能促进 或Rac-1（Rac-1 T17N）的显性负突变形式的过表达，会削弱CX-5011诱导变色的能力。此外，用CX-5011进行细胞处理可诱导Rac-1持久活化，持续至少24小时。值得注意的是，CX-5011不仅能够促进哺乳动物细胞中的巨胞饮作用，而且还能促进 或Rac-1（Rac-1 T17N）的显性-负突变形式的过表达，会削弱CX-5011诱导变色的能力。此外，用CX-5011进行细胞处理可诱导Rac-1持久活化，持续至少24小时。值得注意的是，CX-5011不仅能够促进哺乳动物细胞中的巨胞饮作用，而且还能促进体内斑马鱼模型。因此，基于这些证据，CX-5011因其作为促生存激酶CK2抑制剂和变应性诱导剂的双重功效而被建议作为一种潜在的有前景的癌症治疗化合物。