Uchihara Yuki, Ueda Fumihito, Tago Kenji, Nakazawa Yosuke, Ohe Tomoyuki, Mashino Tadahiko, Yokota Shigenobu, Kasahara Tadashi, Tamura Hiroomi, Funakoshi-Tago Megumi
Division of Hygienic Chemistry, Faculty of Pharmacy, Keio University, Minato-ku, Tokyo, Japan.
Division of Structural Biochemistry, Department of Biochemistry, Jichi Medical University, Shimotsuke-shi, Tochigi-ken, Japan.
PLoS One. 2017 Aug 14;12(8):e0183003. doi: 10.1371/journal.pone.0183003. eCollection 2017.
Anaplastic large cell lymphomas (ALCL) are mainly characterized by harboring the fusion protein nucleophosmin-anaplastic lymphoma kinase (NPM-ALK). The ALK inhibitor, crizotinib specifically induced apoptosis in Ba/F3 cells expressing NPM-ALK by inhibiting the activation of NPM-ALK and its downstream molecule, signal transducer and activator of transcription factor 3 (STAT3). We found that α-tocopherol, a major component of vitamin E, attenuated the effects of crizotinib independently of its anti-oxidant properties. Although α-tocopherol suppressed the inhibitory effects of crizotinib on the signaling axis including NPM-ALK and STAT3, it had no influence on the intake of crizotinib into cells. Crizotinib also directly inhibited the kinase activity of NPM-ALK; however, this inhibitory effect was not altered by the co-treatment with α-tocopherol. Whereas the nuclear localization of NPM-ALK was disappeared by the treatment with crizotinib, the co-treatment with α-tocopherol swept the effect of crizotinib and caused the localization of NPM-ALK in nucleus. The administration of α-tocopherol attenuated the anti-tumor activity of crizotinib against NPM-ALK-provoked tumorigenesis in vivo. Furthermore, the α-tocopherol-induced inhibition of crizotinib-caused apoptosis was also observed in NPM-ALK-positive cells derived from ALCL patients, namely, SUDHL-1 and Ki-JK. Collectively, these results not only revealed the novel mechanism underlying crizotinib-induced apoptosis in NPM-ALK-positive cells, but also suggest that the anti-tumor effects of crizotinib are attenuated when it is taken in combination with vitamin E.
间变性大细胞淋巴瘤（ALCL）主要特征是含有融合蛋白核磷蛋白-间变性淋巴瘤激酶（NPM-ALK）。ALK抑制剂克唑替尼通过抑制NPM-ALK及其下游分子信号转导和转录激活因子3（STAT3）的激活，特异性诱导表达NPM-ALK的Ba/F3细胞凋亡。我们发现，维生素E的主要成分α-生育酚可独立于其抗氧化特性减弱克唑替尼的作用。尽管α-生育酚抑制了克唑替尼对包括NPM-ALK和STAT3在内的信号轴的抑制作用，但它对克唑替尼进入细胞的摄取没有影响。克唑替尼还直接抑制NPM-ALK的激酶活性；然而，这种抑制作用不会因与α-生育酚联合处理而改变。用克唑替尼处理可使NPM-ALK的核定位消失，而与α-生育酚联合处理则消除了克唑替尼的作用，并导致NPM-ALK定位于细胞核。给予α-生育酚可减弱克唑替尼在体内对NPM-ALK引发的肿瘤发生的抗肿瘤活性。此外，在源自ALCL患者的NPM-ALK阳性细胞即SUDHL-1和Ki-JK中也观察到α-生育酚诱导的对克唑替尼引起的凋亡的抑制作用。总的来说，这些结果不仅揭示了克唑替尼诱导NPM-ALK阳性细胞凋亡的新机制，还表明克唑替尼与维生素E联合使用时其抗肿瘤作用会减弱。
