Maziere S, Cassand P, Narbonne J F, Meflah K
Laboratoire de Toxicologie Alimentaire, Université Bordeaux I, Talence, France.
Int J Vitam Nutr Res. 1997;67(4):237-41.
The mechanism by which vitamin A prevents or delays chemical carcinogenesis remains unclear. In addition to these antimutagenic and antiproliferative activities, vitamin A seems able to induce programmed cell death. In this study, we assess the suggested role of vitamin A on the in vitro apoptosis induction in a rat colonic tumor cell line. Several concentrations of retinyl palmitate were added in the culture media. We observed cell proliferation by measuring the (3H)thymidine incorporation, cell differentiation by measuring the intestinal alkaline phosphatase expression, and apoptosis induction by DNA fragmentation and morphological evolution of adherent and floating cells. The results show that vitamin A decreases (3H)thymidine incorporation after 1 day of treatment, induces alkaline phosphatase expression, and increases the number of cells falling in apoptosis. This report confirms the role of vitamin A on the induction of cell differentiation, on the inhibition of cell proliferation and shows the vitamin A capacity to induce apoptosis. These results could be attractive to prevent development of colon cancer by vitamin A supplemented diets.
维生素A预防或延缓化学致癌作用的机制尚不清楚。除了这些抗诱变和抗增殖活性外，维生素A似乎还能够诱导程序性细胞死亡。在本研究中，我们评估了维生素A在大鼠结肠肿瘤细胞系体外诱导凋亡中的作用。在培养基中添加了几种浓度的棕榈酸视黄酯。我们通过测量（3H）胸腺嘧啶核苷掺入来观察细胞增殖，通过测量肠碱性磷酸酶表达来观察细胞分化，并通过DNA片段化以及贴壁和悬浮细胞的形态演变来观察凋亡诱导情况。结果表明，维生素A在处理1天后会减少（3H）胸腺嘧啶核苷掺入，诱导碱性磷酸酶表达，并增加凋亡细胞的数量。本报告证实了维生素A在诱导细胞分化、抑制细胞增殖方面的作用，并显示了维生素A诱导凋亡的能力。这些结果对于通过补充维生素A的饮食预防结肠癌的发生可能具有吸引力。
