Rubin H
Department of Molecular Biology, University of California, Berkeley 94720.
Cancer Res. 1988 May 1;48(9):2512-8.
Seeding 2 X 10(4) cells from a clone of BALB/c 3T3 cells in agar led to the formation of about 100 small colonies (approximate diameter, 0.2 mm) and two large colonies (1-mm diameter). Seven of the former and both of the latter were isolated, and the morphology and growth properties of their cells were observed in repeated weekly passages. The seven subclones derived from the smaller agar colonies spread out on the dish and multiplied more slowly than the parental clone on plastic, but six of them produced more colonies in agar than the parental clone. The two subclones derived from the larger agar colonies had a fully transformed morphology, multiplied much faster than the parental clone on plastic, and produced a high percentage of large colonies in agar. Each of the subclones could be distinguished morphologically from the others and from the parental clone, and most of them could be distinguished on the basis of their colony-forming efficiency in agar. Most of the secondary subclones derived from an early passage on plastic of one of the two large agar clones, died out on the second passage after their isolation. Secondary subclones derived from the same subclone five weeks later had a wide range of fluctuating growth rates, but did not die out on passage. The two rapidly growing subclones derived from large agar colonies initiated fast-growing tumors in nude mice. None of the other subclones produced any visible growth in nude mice over a 3-month period. Large agar colonies of fast growing, morphologically transformed cells appeared once during further passage of the parental clone and two of the subclones. The results reveal a surprising degree of heritable diversity in morphology and growth characteristics of the progeny from a clonal line of nontransformed cells. They also indicate that, in this cell line, only those cells that have a high efficiency (greater than 20%) of large colony formation in agar have the capacity to form tumors in nude mice.
将来自BALB/c 3T3细胞克隆的2×10⁴个细胞接种于琼脂中，形成了约100个小菌落（直径约0.2毫米）和两个大菌落（直径1毫米）。分离出其中7个小菌落和2个大菌落，并在每周重复传代过程中观察其细胞的形态和生长特性。源自较小琼脂菌落的7个亚克隆在培养皿上展开，增殖速度比塑料培养皿上的亲代克隆慢，但其中6个在琼脂中形成的菌落比亲代克隆多。源自较大琼脂菌落的2个亚克隆具有完全转化的形态，在塑料培养皿上的增殖速度比亲代克隆快得多，并且在琼脂中产生的大菌落比例很高。每个亚克隆在形态上都可以与其他亚克隆和亲代克隆区分开来，并且大多数可以根据它们在琼脂中的集落形成效率来区分。源自两个大琼脂克隆之一在塑料上早期传代的大多数第二代亚克隆，在分离后的第二次传代时死亡。五周后源自同一亚克隆的第二代亚克隆具有广泛波动的生长速率，但传代时没有死亡。源自大琼脂菌落的两个快速生长的亚克隆在裸鼠中引发了快速生长的肿瘤。在三个月的时间里，其他亚克隆在裸鼠中均未产生任何可见的生长。在亲代克隆和两个亚克隆的进一步传代过程中，快速生长、形态转化的细胞的大琼脂菌落出现过一次。结果揭示了来自未转化细胞克隆系的子代在形态和生长特征上存在惊人程度的可遗传多样性。它们还表明，在这个细胞系中，只有那些在琼脂中具有高效（大于20%）形成大菌落能力的细胞才有能力在裸鼠中形成肿瘤。
