Kadhim Munira A, Mayah Ammar, Brooks Susan A
Department of Biological and Medical Sciences, Faculty of Health and Life Sciences, Oxford Brookes University, Oxford OX3 0BP, UK.
Cancers (Basel). 2020 Jan 17;12(1):236. doi: 10.3390/cancers12010236.
Ionising radiation (IR) is commonly used for cancer therapy; however, its potential influence on the metastatic ability of surviving cancer cells exposed directly or indirectly to IR remains controversial. Metastasis is a multistep process by which the cancer cells dissociate from the initial site, invade, travel through the blood stream or lymphatic system, and colonise distant sites. This complex process has been reported to require cancer cells to undergo epithelial-mesenchymal transition (EMT) by which the cancer cells convert from an adhesive, epithelial to motile, mesenchymal form and is also associated with changes in glycosylation of cell surface proteins, which may be functionally involved in metastasis. In this paper, we give an overview of metastatic mechanisms and of the fundamentals of cancer-associated glycosylation changes. While not attempting a comprehensive review of this wide and fast moving field, we highlight some of the accumulating evidence from in vitro and in vivo models for increased metastatic potential in cancer cells that survive IR, focusing on angiogenesis, cancer cell motility, invasion, and EMT and glycosylation. We also explore the indirect effects in cells exposed to exosomes released from irradiated cells. The results of such studies need to be interpreted with caution and there remains limited evidence that radiotherapy enhances the metastatic capacity of cancers in a clinical setting and undoubtedly has a very positive clinical benefit. However, there is potential that this therapeutic benefit may ultimately be enhanced through a better understanding of the direct and indirect effects of IR on cancer cell behaviour.
电离辐射（IR）常用于癌症治疗；然而，其对直接或间接暴露于IR的存活癌细胞转移能力的潜在影响仍存在争议。转移是一个多步骤过程，癌细胞从初始部位脱离、侵入、通过血流或淋巴系统传播，并在远处部位定植。据报道，这个复杂的过程需要癌细胞经历上皮-间质转化（EMT），通过该转化癌细胞从黏附性的上皮形式转变为可移动的间质形式，并且还与细胞表面蛋白糖基化的变化有关，这可能在功能上参与转移。在本文中，我们概述了转移机制以及癌症相关糖基化变化的基本原理。虽然我们不打算对这个广泛且快速发展的领域进行全面综述，但我们强调了一些来自体外和体内模型的越来越多的证据，这些证据表明存活于IR后的癌细胞转移潜力增加，重点关注血管生成、癌细胞运动、侵袭以及EMT和糖基化。我们还探讨了暴露于受辐照细胞释放的外泌体的细胞中的间接影响。此类研究结果需要谨慎解读，并且在临床环境中，放疗增强癌症转移能力的证据仍然有限，但其无疑具有非常积极的临床益处。然而，通过更好地理解IR对癌细胞行为的直接和间接影响，这种治疗益处最终有可能得到增强。
