Shiroeda O, Yamaguchi N, Kawai K
Cancer Res. 1987 Sep 1;47(17):4630-3.
Low density lipoprotein receptor activity in cultured rabbit aortic smooth muscle cells was enhanced by the addition of the conditioned medium derived from the serum-free culture of a human lung cancer cell line. By gel filtration, two peaks of low density lipoprotein receptor-enhancing fractions were obtained, and the molecular weights were 140,000 and greater than 850,000. These fractions also stimulated [3H]thymidine incorporation into DNA. Maximal stimulations of the low density lipoprotein receptor activity and [3H]thymidine incorporation were observed at 16 and 20 h after the addition of the conditioned medium, respectively. The apparent Km (about 10 micrograms/ml) was not changed by the addition of the conditioned medium. De novo cholesterol synthesis was also stimulated by the conditioned medium. It is speculated that certain factors released from the cancer cells affect cholesterol metabolism in normal cells.
通过添加源自人肺癌细胞系无血清培养的条件培养基，培养的兔主动脉平滑肌细胞中的低密度脂蛋白受体活性得到增强。通过凝胶过滤，获得了两个低密度脂蛋白受体增强组分峰，分子量分别为140,000和大于850,000。这些组分还刺激了[3H]胸苷掺入DNA。分别在添加条件培养基后16小时和20小时观察到低密度脂蛋白受体活性和[3H]胸苷掺入的最大刺激。添加条件培养基后，表观Km（约10微克/毫升）未发生变化。条件培养基也刺激了胆固醇的从头合成。推测癌细胞释放的某些因子会影响正常细胞中的胆固醇代谢。
