Necroptosis regulates tumor repopulation after radiotherapy via RIP1/RIP3/MLKL/JNK/IL8 pathway
Necroptosis regulates tumor repopulation after radiotherapy via RIP1/RIP3/MLKL/JNK/IL8 pathway
复制标题
坏死性凋亡通过 RIP1/RIP3/MLKL/JNK/IL8 通路调节放疗后肿瘤的增殖
DOI：
10.1186/s13046-019-1423-5
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发表时间：
2019-11-09
影响因子：
11.3
通讯作者：
Huang, Qian
中科院分区：
文献类型：
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作者：
Wang, Yiwei;Zhao, Minghui;Huang, Qian
研究背景放射治疗后肿瘤细胞再增殖是肿瘤放射抵抗和复发的主要原因。本研究旨在探讨放射治疗后肿瘤再增殖的潜在机制，重点是坏死性凋亡是否以及如何参与这一过程。方法采用离体和在体的方法观察放射性损伤后的坏死性凋亡。并在体外和体内肿瘤再增殖模型中研究了坏死凋亡相关蛋白和基因的化学抑制剂或shRNA对坏死凋亡细胞的促生长作用。通过蛋白质印迹和化学发光免疫分析确定坏死性凋亡的下游相关因素。最后，在人类结直肠肿瘤标本中进行鉴定的坏死性凋亡相关生长刺激因子的免疫组织化学染色，以验证与临床结果的关系。结果放射诱导的坏死性凋亡依赖于RIP 1/RIP 3/MLKL通路的激活，体内外实验表明，抑制坏死性凋亡可减弱放射肿瘤细胞对肿瘤报告细胞的生长刺激作用。JNK/IL-8被鉴定为坏死性凋亡过程中pMLKL的下游分子，抑制JNK、IL-8或IL-8受体可显著降低放射治疗后的肿瘤再增殖。此外，IL-8的高表达与结直肠癌患者的不良临床预后相关。结论放射治疗后坏死性凋亡相关的肿瘤再增殖依赖于RIP 1/RIP 3/MLKL/JNK/IL-8通路的激活。这一新途径为理解肿瘤放射抵抗和再增殖机制提供了新的见解，MLKL/JNK/IL-8有望成为阻断肿瘤再增殖以提高结直肠癌放射治疗疗效的靶点。
Background Tumor cell repopulation after radiotherapy is a major cause for the tumor radioresistance and recurrence. This study aims to investigate the underlying mechanism of tumor repopulation after radiotherapy, with focus on whether and how necroptosis takes part in this process. Methods Necroptosis after irradiation were examined in vitro and in vivo. And the growth-promoting effect of necroptotic cells was investigated by chemical inhibitors or shRNA against necroptosis associated proteins and genes in in vitro and in vivo tumor repopulation models. Downstream relevance factors of necroptosis were identified by western blot and chemiluminescent immunoassays. Finally, the immunohistochemistry staining of identified necroptosis association growth stimulation factor was conducted in human colorectal tumor specimens to verify the relationship with clinical outcome. Results Radiation-induced necroptosis depended on activation of RIP1/RIP3/MLKL pathway, and the evidence in vitro and in vivo demonstrated that the inhibition of necroptosis attenuated growth-stimulating effects of irradiated tumor cells on living tumor reporter cells. The JNK/IL-8 were identified as downstream molecules of pMLKL during necroptosis, and inhibition of JNK, IL-8 or IL-8 receptor significantly reduced tumor repopulation after radiotherapy. Moreover, the high expression of IL-8 was associated with poor clinical prognosis in colorectal cancer patients. Conclusions Necroptosis associated tumor repopulation after radiotherapy depended on activation of RIP1/RIP3/MLKL/JNK/IL-8 pathway. This novel pathway provided new insight into understanding the mechanism of tumor radioresistance and repopulation, and MLKL/JNK/IL-8 could be developed as promising targets for blocking tumor repopulation to enhance the efficacy of colorectal cancer radiotherapy.