Alpha-tocopherol attenuates the anti-tumor activity of crizotinib against cells transformed by NPM-ALK

Abstract

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.

Key conditions of alpha-tocopherol encapsulation in gum Arabic dispersions

“…liver cancer). It is also associated to skin healthiness (Ben-Shabat et al, 2013;Lai et al, 2014;Uchihara et al, 2017). TOC generally originates in a vegetable at diverse compositions.…”

EBP2, a novel NPM‐ALK‐interacting protein in the nucleolus, contributes to the proliferation of ALCL cells by regulating tumor suppressor p53

“…NPM1 cDNA and the cDNA encoding N‐terminal Flag NPM1 inserted into MSCV‐Puro retroviral vector. Retroviral vector for NPM‐ALK (K210R) was constructed using MSCV‐Puro‐N‐Flag NPM‐ALK as a template by mutagenesis PCR as previously described [16].…”

“…NPM1 −/− /p53 −/− MEF and p53 −/− MEF were kindly gifted from Pier Paolo Pandolfi (Harvard University) and cultured in DMEM‐high glucose (Nacalai Tesque) supplemented with 10% FBS, 100 units·mL −1 penicillin, 100 μg·mL −1 streptomycin, and 55 μ m 2‐mercaptoethanol (Nacalai Tesque). Ba/F3 cells were infected using RetroNectin (Takara Bio Inc., Shiga, Japan) and MEFs were infected using 10 μg·mL −1 polybrene as reported previously [16]. HEK293T cells were transfected with plasmids using polyethylenimine (PEI) Max (Polyscience inc. Warrington, PA, USA).…”

“…Proteins were eluted within Laemmli's sample buffer at 100°C for 10 min. SDS/PAGE, transfer, and immunoblotting were performed and the intensity of each band was quantified by IMAGEJ software [16].…”

“…[15] reported that NPM‐ALK was distributed in equal amounts between the cytoplasm and nucleus in ALCL cell lines and showed that only the cytoplasmic NPM‐ALK was catalytically active in these cells. On the other hand, we previously reported that the nuclear localization of NPM‐ALK was regulated by its kinase activity [16], suggesting that nuclear NPM‐ALK induces oncogenic features. Although NPM is a nucleolar protein possessing a nucleolar localization signal (NoLS), the N‐terminal portion of NPM‐ALK derived from the NPM gene lacks NoLS.…”