Fleischer N, Chen C, Surana M, Leiser M, Rossetti L, Pralong W, Efrat S
Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, USA.
Diabetes. 1998 Sep;47(9):1419-25. doi: 10.2337/diabetes.47.9.1419.
Development of beta-cell lines for cell therapy of diabetes is hindered by functional deviations of the replicating cells from the normal beta-cell phenotype. In a recently developed cell line, denoted betaTC-tet, derived from transgenic mice expressing the SV40 T antigen (Tag) under control of the tetracycline (Tc) gene regulatory system, growth arrest can be induced by shutting off Tag expression in the presence of Tc. Here, we compared differentiated cell functions in dividing and growth-arrested betaTC-tet cells, both in culture and in vivo. Proliferating cells stably maintained normal glucose responsiveness for >60 passages in culture. Growth-arrested cells survived for months in culture and in vivo and maintained normal insulin production and secretion. After growth arrest, the cells gradually increased their insulin content three- to fourfold. This occurred without significant changes in insulin biosynthetic rates. At high passage numbers, proliferating betaTC-tet cells exhibited an abnormal increase in hexokinase expression. However, the upregulation of hexokinase was reversible upon growth arrest. Growth-arrested cells transplanted intraperitoneally into syngeneic recipients responded to hyperglycemia by a significant increase in insulin secretion. These findings demonstrate that transformed beta-cells maintain function during long periods of growth arrest, suggesting that conditional transformation of beta-cells may be a useful approach for developing cell therapy for diabetes.
用于糖尿病细胞治疗的β细胞系的开发受到复制细胞与正常β细胞表型功能偏差的阻碍。在最近开发的一种细胞系中，称为βTC-tet，它源自转基因小鼠，在四环素（Tc）基因调控系统的控制下表达SV40 T抗原（Tag），在Tc存在的情况下关闭Tag表达可诱导生长停滞。在这里，我们比较了培养中和体内处于分裂状态和生长停滞状态的βTC-tet细胞的分化细胞功能。增殖细胞在培养中稳定维持正常葡萄糖反应性超过60代。生长停滞的细胞在培养中和体内存活数月，并维持正常的胰岛素产生和分泌。生长停滞后，细胞的胰岛素含量逐渐增加三到四倍。这一过程中胰岛素生物合成速率没有显著变化。在传代次数较高时，增殖的βTC-tet细胞的己糖激酶表达出现异常增加。然而，生长停滞时己糖激酶的上调是可逆的。腹腔内移植到同基因受体中的生长停滞细胞对高血糖的反应是胰岛素分泌显著增加。这些发现表明，转化的β细胞在长时间生长停滞期间维持功能，这表明β细胞的条件性转化可能是开发糖尿病细胞治疗方法的一种有用途径。
