Kano Y, Little J B
Cancer Res. 1985 Jun;45(6):2550-5.
Early passage cultures of a strain of normal human diploid fibroblasts were exposed to various doses of X-rays. The cells were serially passaged and followed throughout their life span in vitro. G-banded metaphase chromosome preparations were examined at each subculture to determine the presence of abnormal clones, i.e., groups of cells bearing identical chromosomal rearrangements. It was found that X-irradiation induced random chromosomal rearrangements which persisted throughout the life span of the cells. No abnormal clones were observed among the progeny of four nonirradiated cultures, nor in seven of nine cultures exposed to single radiation doses. On the other hand, multiple abnormal clones emerged among the progeny of cells in all five cultures exposed to multiple sequential radiation doses (three doses of 400 or 600 rads each). Evidence of clonal expansion and attenuation and of clonal succession during serial passaging occurred in these populations. In several cases, these clones expanded to include most of the cell population before the cultures became senescent. These findings are discussed in terms of their possible role in the transformation of human diploid cells by radiation.
一株正常人二倍体成纤维细胞的早期传代培养物接受了不同剂量的X射线照射。这些细胞进行连续传代，并在体外追踪其整个生命周期。在每次传代培养时检查G带中期染色体标本，以确定异常克隆的存在，即携带相同染色体重排的细胞群。结果发现，X射线照射诱导了随机的染色体重排，这些重排在细胞的整个生命周期中持续存在。在四个未照射培养物的后代中，以及在接受单次辐射剂量的九个培养物中的七个中，均未观察到异常克隆。另一方面，在所有五个接受多次连续辐射剂量（每次三剂400或600拉德）的培养物的细胞后代中，出现了多个异常克隆。在这些群体中发生了连续传代过程中的克隆扩增、衰减和克隆更替的证据。在几种情况下，这些克隆在培养物衰老之前扩展到包括大多数细胞群体。就这些发现可能在辐射诱导人二倍体细胞转化中的作用进行了讨论。
