Niu Kai, Chen Xie-Wan, Qin Yu, Zhang Lu-Ping, Liao Rong-Xia, Sun Jian-Guo
Cancer Institute of Chinese People's Liberation Army (PLA), Xinqiao Hospital, Army Medical University, Chongqing, China.
Medical English Department, College of Basic Medicine, Army Medical University, Chongqing, China.
Front Oncol. 2021 Sep 10;11:697227. doi: 10.3389/fonc.2021.697227. eCollection 2021.
The resistance to radiotherapy in lung cancer can be attributed to vasculogenic mimicry (VM) to some extent. Celecoxib (CXB), a selective inhibitor of cyclooxygenase-2 (COX-2), is reported as a radiosensitizer in non-small cell lung cancer (NSCLC). However, whether CXB can regulate VM formation an off-target effect to radiosensitize NSCLC remains unclear. This study aimed to elucidate the mechanism underlying the radiosensitizing effect of CXB on NSCLC, i.e., whether CXB can inhibit VM formation binding to newly identified targets other than COX-2. CXB radiosensitivity assay was performed in BALB/c mice bearing H460 xenografts and C57 mice bearing Lewis lung cancer (LLC) xenografts, which were divided into the control, CXB, irradiation (IR) treatment, and IR plus CXB groups. VM formation was observed using 3D Matrigel, periodic acid solution (PAS) staining, and immunofluorescence staining. The potential off-targets of CXB were screened using Protein Data Bank (PDB) database, MGLTools 1.5.6, and AutoDock Vina 1.1.2 and confirmed by Western blotting, enzyme activity assay, and RNA interference experiments and by immunohistochemistry experiments. CXB treatment almost eliminated the enhancement of VM formation by IR and , partially due to COX-2 inhibition. Four potential off-targets were predicted by molecular docking. Among them, aminopeptidase N (APN) and integrin alpha-V (ITAV) were remarkably inhibited in protein expression and enzyme activity or , consistent with the remarkable reduction of VM formation in H460 xenografts in BALB/c mice. In conclusion, CXB dramatically blocked VM through inhibiting newly identified off-targets APN and ITAV, other than COX-2, then radiosensitizing NSCLC.
肺癌对放疗的抗性在一定程度上可归因于血管生成拟态（VM）。塞来昔布（CXB）是环氧化酶-2（COX-2）的选择性抑制剂，据报道在非小细胞肺癌（NSCLC）中是一种放射增敏剂。然而，CXB是否能调节VM形成以及对NSCLC产生放射增敏作用的脱靶效应仍不清楚。本研究旨在阐明CXB对NSCLC放射增敏作用的潜在机制，即CXB是否能通过结合除COX-2之外新发现的靶点来抑制VM形成。对携带H460异种移植瘤的BALB/c小鼠和携带Lewis肺癌（LLC）异种移植瘤的C57小鼠进行CXB放射敏感性测定，这些小鼠被分为对照组、CXB组、照射（IR）治疗组和IR加CXB组。使用3D基质胶、过碘酸溶液（PAS）染色和免疫荧光染色观察VM形成。利用蛋白质数据库（PDB）数据库、MGLTools 1.5.6和AutoDock Vina 1.1.2筛选CXB的潜在脱靶靶点，并通过蛋白质印迹、酶活性测定、RNA干扰实验和免疫组织化学实验进行确认。CXB处理几乎消除了IR对VM形成的促进作用，部分原因是COX-2受到抑制。通过分子对接预测了四个潜在的脱靶靶点。其中，氨肽酶N（APN）和整合素α-V（ITAV）的蛋白表达和酶活性受到显著抑制，这与BALB/c小鼠H460异种移植瘤中VM形成的显著减少一致。总之，CXB通过抑制新发现的除COX-2之外的脱靶靶点APN和ITAV，显著阻断VM，从而使NSCLC产生放射增敏作用。
