Morvan Daniel, Demidem Aicha
UDA University, 49 Boulevard François Mitterrand, CS 60032, 63001 Clermont Ferrand Cedex 1, France; Centre Jean Perrin, 58 Rue Montalembert, F-63011 Clermont Ferrand, France.
UMR 1019 INRA/UDA University, ECREIN, Laboratoire de Biochimie Biologie Moléculaire, Faculté de Pharmacie, 28 Place Henri Dunant, F-63001 Clermont Ferrand, France.
Biochim Biophys Acta. 2014 Mar;1840(3):1092-104. doi: 10.1016/j.bbagen.2013.11.022. Epub 2013 Dec 1.
Localized radiotherapy is long known to cause damages to not only targeted but also non-targeted cells, the so-called bystander (BS) effect. Recently, BS effect was demonstrated in response to chemotherapy. To get further insight into the mechanism of chemotherapy-induced BS effect in vivo, we investigated the response of normal tissues and untreated BS melanomas, at distance from localized chemotherapy-treated melanomas.
B16 melanoma cells were inoculated sc in one flank, in mice. Chemotherapy was administered intratumorally. After 3 weeks, untreated melanomas were implanted into the other flank. Tumors were analyzed morphologically, and using metabolomics and transcriptomics.
Locally-treated melanomas showed growth inhibition and pleiotropic metabolic and transcriptional alterations. Tumors recovered slow proliferation while exhibiting prominent oxidative stress response (decreased glutathione level, and increased expression of genes including Mt1, Gpx3, Sod3, and Hmox1). Plasma contained increased levels of oxidative stress products. However, liver and soleus muscle displayed unaltered morphological characteristics. In contrast, untreated BS melanomas induced from naive B16 cells showed reduced growth, marked oxidative stress response (decreased glutathione level, and increased expression of genes including Sod2, Gpx1 and Gsr), and ras oncogene expression alterations. Furthermore, metabolomics and transcriptomics enabled to estimate the proportion of cells undergoing the BS effect within treated tumors.
Treatment of tumors with chemotherapy induces BS effects, underpinned by oxidative stress, in abnormal proliferating tissues in vivo, not in normal tissue, that significantly contribute to overall tumor response. General significance BS effect significantly contributes to response to chemotherapy, and may be exploited to improve overall response to cancer treatment.
长期以来，人们已知局部放疗不仅会对靶向细胞造成损伤，还会对非靶向细胞造成损伤，即所谓的旁观者（BS）效应。最近，在化疗反应中也证实了旁观者效应。为了进一步深入了解体内化疗诱导的旁观者效应的机制，我们研究了正常组织以及与局部化疗处理的黑色素瘤有一定距离的未处理旁观者黑色素瘤的反应。
将B16黑色素瘤细胞接种于小鼠一侧胁腹的皮下。进行瘤内化疗。3周后，将未处理的黑色素瘤植入另一侧胁腹。对肿瘤进行形态学分析，并使用代谢组学和转录组学方法进行研究。
局部处理的黑色素瘤显示出生长抑制以及多效性代谢和转录改变。肿瘤恢复缓慢增殖，同时表现出显著的氧化应激反应（谷胱甘肽水平降低，包括Mt1、Gpx3、Sod3和Hmox1等基因的表达增加）。血浆中氧化应激产物水平升高。然而，肝脏和比目鱼肌的形态特征未发生改变。相比之下，由未处理的B16细胞诱导产生的未处理旁观者黑色素瘤显示出生长减缓、明显的氧化应激反应（谷胱甘肽水平降低，包括Sod2、Gpx1和Gsr等基因的表达增加）以及ras癌基因表达改变。此外，代谢组学和转录组学能够估计处理过的肿瘤内经历旁观者效应的细胞比例。
化疗治疗肿瘤会在体内异常增殖组织而非正常组织中诱导旁观者效应，这种效应以氧化应激为基础，对总体肿瘤反应有显著贡献。普遍意义：旁观者效应显著有助于化疗反应，并且可能被利用来改善对癌症治疗的总体反应。
