High expression of GADD-45alpha and VEGF induced tumor recurrence via upregulation of IL-2 after photodynamic therapy using NPe6.
High expression of GADD-45alpha and VEGF induced tumor recurrence via upregulation of IL-2 after photodynamic therapy using NPe6.
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DOI：
10.3892/ijo.32.2.397
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发表时间：
2008-02
影响因子：
5.2
通讯作者：
K. Ohtani;J. Usuda;S. Ichinose;T. Ishizumi;T. Hirata;T. Inoue;S. Maehara;K. Imai;M. Kubota;Yoshihiko Tsunoda;M. Yamada;H. Tsutsui;K. Yamada;Y. Kuroiwa;K. Furukawa;T. Okunaka;H. Kato
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作者：
K. Ohtani;J. Usuda;S. Ichinose;T. Ishizumi;T. Hirata;T. Inoue;S. Maehara;K. Imai;M. Kubota;Yoshihiko Tsunoda;M. Yamada;H. Tsutsui;K. Yamada;Y. Kuroiwa;K. Furukawa;T. Okunaka;H. Kato
NPe6是一种用于光动力治疗（PDT）的新型第二代光敏剂。使用 NPe6 和二极管激光 (664 nm) 的 PDT 会诱导细胞死亡、炎症反应、免疫反应和微血管系统损伤。在本研究中，我们使用细胞因子过表达的 Lewis 肺癌 (LLC)、LLC-IL-2 细胞在体外和体内评估了免疫反应和增强的血管生成对 NPe6-PDT 抗肿瘤效果的影响。我们通过体外 DNA 微阵列分析表明，在以杀死 90% 细胞的剂量 (LD90) 施用 NPe6-PDT 后 3 小时，IL-2 和 GADD-45α（生长停滞和 DNA 损伤 45α）mRNA 表达被诱导。与体外亲本 LLC 细胞相比，IL-2 过表达细胞（LLC/IL-2 细胞）对克隆形成性的丧失具有抵抗力。此外，在雌性C57BL/6小鼠中，NPe6-PDT在LLC肿瘤中的治愈率为66.7%，而在LLC/IL-2肿瘤中的治愈率仅为16.6%，并且IL-2的过度表达导致NPe6-PDT失败，并导致体内肿瘤复发。这些结果表明IL-2表达可能在减弱NPe6-PDT的抗肿瘤作用中发挥不利作用。据报道，尤其是血管内皮生长因子(VEGF)的表达可能导致PDT后肿瘤复发，并对减弱PDT的抗肿瘤活性产生不利影响。 LLC/IL-2肿瘤的免疫组化分析结果显示，PDT后这些肿瘤中GADD-45α和VEGF的表达被诱导，特别是PDT后12小时，表达水平远高于LLC肿瘤。我们使用体外和体内模型的研究结果表明，PDT 引起的细胞死亡受到 GADD-45α 表达诱导的抑制，并且 IL-2 上调介导的 VEGF 表达增强促进了肿瘤复发。因此，推测使用IL-2抑制剂可能会提高NPe6-PDT的疗效。
NPe6 is a novel second-generation photosensitizer used for photodynamic therapy (PDT). PDT using NPe6 and diode laser (664 nm) induces cell death, inflammatory reactions, immunological responses and damage to the microvasculature. In this study, we evaluated the influence of the immunological responses and of enhanced angiogenesis on the anti-tumor effect of NPe6-PDT using cytokine-overexpressing Lewis lung carcinoma (LLC), LLC-IL-2 cells both in vitro and in vivo. We showed by DNA microarray analysis in vitro that IL-2 and GADD-45alpha (growth arrest and DNA damage 45 alpha) mRNA expressions were induced by 3 h after NPe6-PDT applied at a dose killing 90% of the cells (LD90). IL-2-overexpressing cells (LLC/IL-2 cells) were resistant to the loss of clonogenicity as compared to the parental LLC cells in vitro. Furthermore, in female C57BL/6 mice, NPe6-PDT produced a cure rate of 66.7% in LLC tumors, whereas the cure rate was only 16.6% in LLC/IL-2 tumors, and overexpression of IL-2 caused failure of NPe6-PDT, with tumor recurrence, in vivo. These results suggest that IL-2 expression may play an unfavorable role in attenuation of the antitumor effect of NPe6-PDT. It has been reported that the expression of vascular endothelial growth factor (VEGF), in particular, may cause tumor recurrence after PDT and exert unfavorable effect in relation to attenuate the anti-tumor activity of PDT. Results of immunohistochemical analysis of LLC/IL-2 tumors have revealed that the expressions of GADD-45alpha and VEGF are induced in these tumors after PDT, and in particular, 12 h after PDT, the expression levels were much higher as compared with those in the LLC tumors. The results of our studies using in vitro and in vivo models suggest that the cell death caused by PDT was inhibited by induction of GADD-45alpha expression and that tumor recurrence was promoted by the enhancement of VEGF expression mediated by IL-2 upregulation. Therefore, it is speculated that the use of an IL-2 inhibitor may improve the efficacy of NPe6-PDT.