Kennedy A R, Little J B
Department of Physiology, Harvard University, School of Public Health, Boston, MA 02115, USA.
Carcinogenesis. 1980;1(12):1039-47. doi: 10.1093/carcin/1.12.1039.
We have performed experiments designed to investigate the mechanism for the enhancement of radiation transformation in vitro by 12-O-tetradecanoylphorbol-13-acetate (TPA). Two types of experiments, involving C3H 10T1/2 cells and 100 rad X-ray exposures with subsequent TPA treatment, are reported here. In one set of experiments, cultures were initially seeded at differing initial cell densities prior to irradiation. In the other series of experiments, cultures exposed to 100 rads and TPA contained the same initial cell densities (about 300 viable cells per dish); these cultures were allowed to reach confluence and were then reseeded at various cell densities to allow a second cycle of growth to confluence (which involved different numbers of cell divisions). We have observed that the number of transformed foci which ultimately developed per dish treated with 100 rads and TPA remains approximately constant even though the cell density (initial or reseeded) is varied over several orders of magnitude. The yield of transformants per dish which occurred following this treatment was similar to those previously observed in cultures irradiated with higher doses (400-600 rads) of X-rays alone. Our results suggest that a similar mechanism for the induction of malignant transformation may be involved for high doses of radiation alone or for a low dose of radiation followed by TPA treatment.
我们进行了旨在研究12 - O - 十四烷酰佛波醇 - 13 - 乙酸酯（TPA）增强体外辐射转化机制的实验。本文报道了两类涉及C3H 10T1/2细胞以及100拉德X射线照射并随后进行TPA处理的实验。在一组实验中，培养物在辐照前最初以不同的初始细胞密度接种。在另一系列实验中，接受100拉德和TPA处理的培养物具有相同的初始细胞密度（每皿约300个活细胞）；这些培养物培养至汇合状态，然后以不同的细胞密度重新接种，以进行第二轮生长至汇合（这涉及不同数量的细胞分裂）。我们观察到，尽管细胞密度（初始或重新接种的）在几个数量级范围内变化，但每皿经100拉德和TPA处理后最终形成的转化灶数量大致保持恒定。此处理后每皿转化体的产量与之前在仅接受较高剂量（400 - 600拉德）X射线照射的培养物中观察到的产量相似。我们的结果表明，单独高剂量辐射或低剂量辐射后进行TPA处理可能涉及类似的诱导恶性转化机制。
