Fonagy A, Swiderski C, Ostrovsky A M, Bolton W E, Freeman J W
Department of Surgery, Lucille Parkey Markey Cancer Center, Lexington, Kentucky 40536.
Cancer Res. 1994 Apr 1;54(7):1859-64.
Steady-state level of nucleolar P120 protein and P120 mRNA was compared to the doubling time and S-phase fraction in human breast cancer cell lines growing exponentially and in similar cells treated with a single dose of P120 antisense oligodeoxynucleotides. The study included six breast cancer cell lines and one nontransformed breast cell line with doubling times from 1.1 to 5.5 days and with S-phase fractions from 35 to 9%. P120 expression level was determined by densitometric computerized evaluation of protein and mRNA blots and with a quantitative 32P-reverse transcriptase-polymerase chain reaction method developed for small-scale samples. In the slowest growing normal cell line, P120 expression level was only about 10% of the level found in the most rapidly growing cancer cell line. The amount of P120 mRNA was highly correlated with the amount of P120 protein (P = 0.0001), indicating that P120 accumulation is regulated in these cells primarily at a transcriptional level. There was also a significant positive correlation between the level of P120 protein/mRNA and doubling time of cell lines (P = 0.0008) or percentage of S-phase cells (P = 0.210). P120 antisense oligomer treatment decreased the growth rate of cells in a dose-dependent manner, and the inhibition reached 70% at 100 microM concentration. Both P120 mRNA and P120 protein levels were also decreased by approximately 70% in cells treated with 100 microM P120 antisense oligomer. Slowly growing cells exhibited 50% inhibition by treatment at a proportionally lower concentration of P120 antisense oligomer than fast growing cells. This study shows that the expression of P120, measured either at the protein or the mRNA level, correlates with proliferation rate, identifying P120 as a cell proliferation marker.
将处于指数生长期的人乳腺癌细胞系以及用单剂量P120反义寡脱氧核苷酸处理的类似细胞中的核仁P120蛋白和P120 mRNA的稳态水平与倍增时间和S期分数进行比较。该研究包括6种乳腺癌细胞系和1种未转化的乳腺细胞系，其倍增时间为1.1至5.5天，S期分数为35%至9%。通过蛋白质和mRNA印迹的光密度计算机化评估以及为小规模样品开发的定量32P逆转录酶-聚合酶链反应方法来测定P120表达水平。在生长最慢的正常细胞系中，P120表达水平仅为生长最快的癌细胞系中发现水平的约10%。P120 mRNA的量与P120蛋白的量高度相关（P = 0.0001），表明P120在这些细胞中的积累主要在转录水平受到调节。P120蛋白/mRNA水平与细胞系的倍增时间（P = 0.0008）或S期细胞百分比（P = 0.210）之间也存在显著正相关。P120反义寡聚物处理以剂量依赖的方式降低细胞的生长速率，在100 microM浓度下抑制率达到70%。在用100 microM P120反义寡聚物处理的细胞中，P120 mRNA和P120蛋白水平也均降低了约70%。与快速生长的细胞相比，缓慢生长的细胞在用比例更低浓度的P120反义寡聚物处理时表现出50%的抑制率。这项研究表明，无论是在蛋白质水平还是mRNA水平测量的P120表达都与增殖速率相关，将P120鉴定为细胞增殖标志物。
