Azuma M, Yoshida H, Kawamata H, Yanagawa T, Furumoto N, Sato M
Second Department of Oral and Maxillofacial Surgery, Tokushima University School of Dentistry, Japan.
Cancer Res. 1988 May 15;48(10):2898-903.
We have found that reversible differentiation into the myoepithelial cells of a human salivary gland adenocarcinoma cell line (HSG) occurs in growth medium containing dibutyryl cAMP (dB-cAMP). In the current study, the relationship between intracellular cAMP levels and anchorage-dependent and -independent growth or ras oncogene of p21 levels was analyzed in the differentiation process toward myoepithelial cells of HSG cells cultured in the presence of dB-cAMP. Correlation between the concentrations of dB-cAMP and intracellular cAMP in the HSG cells was statistically significant. There was a significant inverse correlation between the concentrations of dB-cAMP and colony-forming ability of the cells in semisolid agar or on a plastic surface. We have found the expression of ras p21 protein in HSG cells. When HSG cells were cultured in the presence of dB-cAMP and were committed to differentiate into myoepithelial cells, it was shown by double-antibody labeling technique and/or immunoblotting that the committed cells expressed myosin with a concomitant decrease of ras p21 protein. Moreover, intracellular cAMP levels were found to be inversely associated with ras p21 content of the cells. These findings indicate that the intracellular cAMP levels regulate significantly cell proliferation and ras p21 expression in HSG cells.
我们发现，在含有二丁酰环磷腺苷（dB - cAMP）的生长培养基中，人唾液腺腺癌细胞系（HSG）可发生可逆性分化为肌上皮细胞。在当前研究中，分析了在dB - cAMP存在下培养的HSG细胞向肌上皮细胞分化过程中，细胞内cAMP水平与锚定依赖性和非依赖性生长或p21的ras癌基因水平之间的关系。HSG细胞中dB - cAMP浓度与细胞内cAMP之间的相关性具有统计学意义。在半固体琼脂或塑料表面上，dB - cAMP浓度与细胞的集落形成能力之间存在显著的负相关。我们在HSG细胞中发现了ras p21蛋白的表达。当HSG细胞在dB - cAMP存在下培养并开始分化为肌上皮细胞时，通过双抗体标记技术和/或免疫印迹表明，已分化细胞表达肌球蛋白，同时ras p21蛋白减少。此外，发现细胞内cAMP水平与细胞的ras p21含量呈负相关。这些发现表明，细胞内cAMP水平显著调节HSG细胞的增殖和ras p21表达。
