Engelholm S A, Vindeløv L L, Spang-Thomsen M, Brünner N, Tommerup N, Nielsen M H, Hansen H H
Eur J Cancer Clin Oncol. 1985 Jul;21(7):815-24. doi: 10.1016/0277-5379(85)90221-4.
Specimens from a human small cell carcinoma of the lung were established as a cell line in vitro. Flow cytometric DNA analysis demonstrated only one tumor cell population in the parent tumor as well as in the early passages in vitro. After six passages in vitro, two new subpopulations with different DNA content appeared. By cloning, permanent cell lines were established from the new subpopulations, whereas the original population stopped growing. The cloned cell lines were characterized by morphology, chromosomes analysis, electron microscopy and plating efficiency; the stability of the DNA content was examined regularly by flow cytometric DNA analysis and instability was found in one of the cloned cell lines. Chromosome analysis showed that the cloned cell lines consisted of more than one population after 17 in vitro passages. Both cloned cell lines produced tumors in nude mice. Genetic instability was demonstrated in these mouse-grown tumors as well. Development of resistance to antineoplastic treatment may be due to heterogeneity in sensitivity among subpopulations in a tumor. Isolation of populations with different DNA contents allows the study of interaction between subpopulations and the observations provide evidence in support of the hypothesis of clonal evolution.
来自人类肺小细胞癌的标本在体外建立了细胞系。流式细胞术DNA分析表明，原发肿瘤以及体外早期传代培养的细胞中仅存在一个肿瘤细胞群体。体外传代6次后，出现了两个具有不同DNA含量的新亚群。通过克隆，从新亚群中建立了永久细胞系，而原始群体停止生长。对克隆的细胞系进行了形态学、染色体分析、电子显微镜检查和接种效率检测；通过流式细胞术DNA分析定期检测DNA含量的稳定性，发现其中一个克隆细胞系存在不稳定性。染色体分析表明，体外传代17次后，克隆细胞系由不止一个群体组成。两个克隆细胞系均可在裸鼠体内形成肿瘤。在这些裸鼠生长的肿瘤中也证实了基因不稳定性。肿瘤对抗肿瘤治疗产生耐药性的原因可能是肿瘤亚群之间敏感性的异质性。分离具有不同DNA含量的群体有助于研究亚群之间的相互作用，这些观察结果为克隆进化假说提供了支持证据。
