a Molecular Stress and Stem Cell Biology Group, School of Biotechnology, KIIT University , Bhubaneswar , India.
b Hemalata Hospitals and Research Centre , Bhubaneswar , India.
Int J Radiat Biol. 2019 Jun;95(6):667-679. doi: 10.1080/09553002.2019.1580401. Epub 2019 Mar 20.
Radiation therapy is an integral part of current treatment modality for colorectal cancer. Recent studies have revealed the presence of cancer stem-like cells (CSCs) population, in different tumors are responsible for therapeutic resistance and disease relapse, including colorectal cancer with poorer survival rate. Hence, characterization of the effect of Ionizing Radiation (IR) in colorectal cancer may serve to explain possible mechanisms. Parental HCT116 and HCT-15 cells and derived colonospheres were irradiated and dose was optimized based on cell survival assay and cell cycle analysis. DNA damage response (DDR) was elucidated by γH2AX foci formation, COMET assay, and ATM, p-ATM, ERCC1 expression post-treatment. The expression level of developmental marker (β-catenin), CSC markers (CD44, KLF4) and telomeric components (TRF2, RAP1, hTERT) were evaluated. We observed cell survival was more in colonospheres post-irradiation and also exhibited decreased γH2AX foci, olive tail moment, increased ERCC1, and p-ATM expression than its parental counterpart which corresponds to efficient DDR. Differential expression of developmental marker, CSC markers, and telomeric components were observed after irradiation. This study highlighted the presence of CSC phenotype in colonospheres having increased DNA repair capacity. Differential expression of developmental marker, CSC markers and telomeric components between parental and colonospheres may contribute in radio-resistance property of CSCs.
放射治疗是目前治疗结直肠癌的重要方法之一。最近的研究表明，不同肿瘤中存在癌症干细胞样细胞（CSC）群体，这些细胞是导致治疗抵抗和疾病复发的原因之一，包括结直肠癌患者的生存率较低。因此，研究电离辐射（IR）对结直肠癌的影响可能有助于解释可能的机制。 我们使用亲本 HCT116 和 HCT-15 细胞和衍生的类器官进行照射，并根据细胞存活实验和细胞周期分析优化剂量。通过 γH2AX 焦点形成、彗星试验和治疗后 ATM、p-ATM、ERCC1 表达来阐明 DNA 损伤反应（DDR）。评估了发育标记物（β-连环蛋白）、CSC 标记物（CD44、KLF4）和端粒成分（TRF2、RAP1、hTERT）的表达水平。 我们观察到，照射后类器官的细胞存活率更高，γH2AX 焦点、橄榄尾矩减少，ERCC1 和 p-ATM 表达增加，与有效的 DDR 相对应。照射后观察到发育标记物、CSC 标记物和端粒成分的差异表达。 这项研究强调了类器官中存在具有增加 DNA 修复能力的 CSC 表型。亲本细胞和类器官之间发育标记物、CSC 标记物和端粒成分的差异表达可能有助于 CSCs 的放射抵抗特性。
