Yun Hong Shik, Baek Jeong-Hwa, Yim Ji-Hye, Um Hong-Duck, Park Jong Kuk, Song Jie-Young, Park In-Chul, Kim Jae-Sung, Lee Su-Jae, Lee Chang-Woo, Hwang Sang-Gu
a Division of Radiation Cancer Biology, Korea Institute of Radiological and Medical Sciences , Seoul , South Korea.
b Department of Life Science , College of Natural Sciences, Hanyang University , Seoul , South Korea.
Cancer Biol Ther. 2016;17(2):208-18. doi: 10.1080/15384047.2016.1139232.
Tumor cell radioresistance is a major contributor to radiotherapy failure, highlighting the importance of identifying predictive biomarkers for radioresistance. In this work, we established a radioresistant H460 (RR-H460) cell line from parental radiosensitive H460 lung cancer cells by exposure to fractionated radiation. The radiation-resistant, anti-apoptotic phenotype of RR-H460 cell lines was confirmed by their enhanced clonogenic survival and increased expression of the radioresistance genes Hsp90 and Her-3. RR-H460 cells displayed characteristics of cancer stem-like cells (CSCs), including induction of the surface marker CD44 and stem cell markers Nanog, Oct4, and Sox2. RR-H460 cells also exhibited sphere formation and malignant behavior, further supporting a CSC phenotype. Using proteomic analyses, we identified 8 proteins that were up-regulated in RR-H460 CSC lines and therefore potentially involved in radioresistance and CSC-related biological processes. Notably, 4 of these-PAI-2, NOMO2, KLC4, and PLOD3-have not been previously linked to radioresistance. Depletion of these individual genes sensitized RR-H460 cells to radiotoxicity and additively enhancing radiation-induced apoptosis. Our findings suggest the possibility of integrating molecular targeted therapy with radiotherapy as a strategy for resolving the radioresistance of lung tumors.
肿瘤细胞的放射抗性是放疗失败的主要原因，这凸显了识别放射抗性预测生物标志物的重要性。在这项研究中，我们通过对亲本放射敏感的H460肺癌细胞进行分次照射，建立了一种放射抗性的H460（RR-H460）细胞系。RR-H460细胞系的抗辐射、抗凋亡表型通过其增强的克隆形成存活率以及放射抗性基因Hsp90和Her-3表达的增加得到证实。RR-H460细胞表现出癌症干细胞样细胞（CSC）的特征，包括表面标志物CD44以及干细胞标志物Nanog、Oct4和Sox2的诱导表达。RR-H460细胞还表现出成球能力和恶性行为，进一步支持了CSC表型。通过蛋白质组学分析，我们鉴定出8种在RR-H460 CSC系中上调的蛋白质，因此它们可能参与放射抗性和CSC相关的生物学过程。值得注意的是，其中4种——PAI-2、NOMO2、KLC4和PLOD3——以前尚未与放射抗性相关联。这些单个基因的缺失使RR-H460细胞对放射毒性敏感，并累加增强辐射诱导的细胞凋亡。我们的研究结果表明，将分子靶向治疗与放疗相结合作为解决肺肿瘤放射抗性策略的可能性。
