放射敏感性与染色体诱导易位的线形关系及其应用研究

The Linear Relationship Between Chromosome Induced-Translocation And Radiosensitivity of Human Tumor Cells

应用荧光原位杂交（ＦＩＳＨ）方法，研究人类恶性肿瘤细胞放射敏感性与照射后染色体易位 畸变关系及其临床应用的可行性．采用３个放射敏感性不同的人类恶性肿瘤细胞株：鼻咽鳞癌 （ＣＮＥ）、肺腺癌（ＳＰＣ－Ａ１）和乳腺腺癌（ＭＣＦ－７）．用常规集落形成方法，测定不同照射 剂 量下、不同敏感性肿瘤细胞的存活率．经秋水仙素阻断细胞分裂周期，低渗、固定等常规染色 体制片过程和采用２， ８号染色体涂染探针及ＦＩＳＨ方法，测定照射后２４ ｈ肿瘤细胞２， ８号染色 体内在的和辐射诱导的易位畸变量．结果发现，未照射的对照细胞内， ２， ８号染色体都存在不 同程度的内在易位畸变．经分别照射２， ４， ６ Ｇｙ后２４ ｈ，ＣＮＥ，ＳＰＣ－Ａ１和ＭＣＦ－７细胞诱导生 成的残存染色体易位畸变与照射剂量相关性强，能够反映细胞的放射敏感性；此外，所有细 胞株中诱导生成的２， ８号染色体易位畸变与细胞存活率也存在良好相关性，相关系数分 别为 ０．９７和０．９８．该结果同时表明照射诱导易位畸变存在染色体簇性，与染色体大小无关． 由此可见，诱导的残存染色体易位畸变与照射剂量呈线形关系．采用ＦＩＳＨ方法计数照射诱导 的残存染色体易位畸变，在预测不同的?

Fluorescence in situ hybridization (FISH) was used to investigate the relationship between induced-translocation of chromosome af ter radiation and radiosensitivity of tumor cells and to see whether the r esult can be used to predict the radiosensitivity of human tumor cell lines, and thereby to provide a potential means of assessing cell radiosensitivity. Three human cell lines with different radiosensitivity, i.e. a nasopharyngeal cell lin e (CNE), a lung adenocarcinoma cell line (SPC-A1) and a breast adenocarcinoma ce ll line(MCF-7), were used and assessed for clonogenic cell survival after radia tion with 1, 2, 4, 6 and 8 Gy and for radiation-induced aberrations in two chro mosomes(number 2 and 8) 24 h after irradiation with 2, 4and 6 Gy . The number of radiation-induced aberration in chromosome 2 and chromosome 8 remaining 24 h after irradiation could reflect the radiosensitivity of th e cells, and there was a good relationship between induced aberrations in chromo some 2 and chromosome 8 and cell survival for all the three cell lines with the related coefficients 0.97 and 0.98 respectively. Thus, the induced-aberration, observed by means of the method ofFISH, can be used to predict the radiosensitivity oftumor cells.