Auersperg N, Siemens C H, Krystal G, Myrdal S E
Cancer Res. 1986 Nov;46(11):5715-23.
Adult rat adrenal cells, infected with Kirsten murine sarcoma virus in early passage, transform consistently in 10% fetal bovine serum (FBS)-supplemented medium. Substitution of 3% horse serum (HS) for FBS reverses early foci and delays transformation. The influence of the serum on DNA synthesis, anchorage dependence, tumorigenicity, and subcellular Mr 21,000 transforming protein (p21) distribution was followed from infection in passage 1 to complete transformation. In FBS, increased expression of p21 preceded other evidence of transformation. Subsequently, p21-positive cells transformed morphologically, but initially their growth parallelled that of coexisting untransformed cells. Foci formed at passages 5 to 10, and the cells became anchorage independent and tumorigenic at passages 10 to 20. As transformation in FBS progressed, p21 relocated from a diffuse distribution to sites of retraction from substrata and then to ruffles and lamellae on cellular processes. Early in transformation, HS-medium reduced proliferation of morphologically normal and morphologically transformed p21-positive cells. This effect was counteracted by the addition of FBS or the Mr 50,000 to 100,000 fraction of FBS. Fully transformed, tumorigenic cells grew rapidly in both sera but, if transferred from FBS to HS, became more anchorage and density dependent, and p21 relocated from cell processes to the cell bodies. In immortal lines, the substitution of HS for FBS accelerated rather than delayed the progression of Kirsten murine sarcoma virus-induced transformation. These results show that Kirsten murine sarcoma virus-induced transformation of adult presenescent cells is controlled by physiological factors to which immortal cells appear refractory. The changes in subcellular distribution of p21 during transformation parallel the expression of some, but not other, transformation parameters and suggest a possible association of p21 with increased membrane activity.
早期传代感染了 Kirsten 小鼠肉瘤病毒的成年大鼠肾上腺细胞，在补充有 10%胎牛血清（FBS）的培养基中能持续发生转化。用 3%马血清（HS）替代 FBS 可使早期病灶逆转并延迟转化。从第 1 代感染到完全转化，跟踪了血清对 DNA 合成、贴壁依赖性、致瘤性以及亚细胞 Mr 21,000 转化蛋白（p21）分布的影响。在 FBS 中，p21 表达增加先于其他转化证据。随后，p21 阳性细胞发生形态转化，但最初它们的生长与共存的未转化细胞平行。在第 5 至 10 代形成病灶，细胞在第 10 至 20 代时变得不依赖贴壁且具有致瘤性。随着 FBS 中转化的进展，p21 从弥漫分布重新定位到从基质回缩的部位，然后到细胞突起上的褶皱和片状伪足。在转化早期，HS 培养基降低了形态正常和形态转化的 p21 阳性细胞的增殖。添加 FBS 或 FBS 的 Mr 50,000 至 100,000 组分可抵消这种作用。完全转化的致瘤细胞在两种血清中均快速生长，但如果从 FBS 转移到 HS 中，则变得更依赖贴壁和密度，并且 p21 从细胞突起重新定位到细胞体。在永生细胞系中，用 HS 替代 FBS 加速而非延迟了 Kirsten 小鼠肉瘤病毒诱导的转化进程。这些结果表明，Kirsten 小鼠肉瘤病毒诱导的成年早衰细胞转化受生理因素控制，而永生细胞似乎对这些因素不敏感。转化过程中 p21 的亚细胞分布变化与一些但不是其他转化参数的表达平行，并提示 p21 可能与膜活性增加有关。
