Towhid Syeda T, Liu Gui-Lai, Ackermann Teresa F, Beier Norbert, Scholz Wolfgang, Fuchß Thomas, Toulany Mahmoud, Rodemann Hans-Peter, Lang Florian
Department of Physiology, University of Tübingen, Tübingen, Germany.
Cell Physiol Biochem. 2013;32(4):838-48. doi: 10.1159/000354486. Epub 2013 Sep 20.
The serum and glucocorticoid inducible kinase SGK1, which was originally cloned from mammary tumor cells, is highly expressed in some but not all tumors. SGK1 confers survival to several tumor cells. Along those lines, the number of colonic tumors following chemical carcinogenesis was decreased in SGK1 knockout mice. Recently, a highly selective SGK inhibitor (EMD638683) has been developed. The present study explored whether EMD638683 affects survival of colon carcinoma cells in vitro and impacts on development of colonic tumors in vivo.
Colon carcinoma (Caco-2) cells were exposed to EMD638683 with or without exposure to radiation (3 Gray) and cell volume was estimated from forward scatter, phosphatidylserine exposure from annexin V binding, mitochondrial potential from JC-9 fluorescence, caspase 3 activity from CaspGlow Fluorescein staining, DNA degradation from propidium iodide staining as well as late apoptosis from annexin-V FITC and propidium iodide double staining. In vivo tumor growth was determined in wild type mice subjected to chemical carcinogenesis (intraperitoneal injection of 20 mg/kg 1,2-dimethylhydrazine followed by three cycles of 30 g/L synthetic dextran sulfate sodium in drinking water for 7 days).
EMD638683 treatment significantly augmented the radiation-induced decrease of forward scatter, increase of phosphatidylserine exposure, decrease of mitochondrial potential, increase of caspase 3 activity, increase of DNA fragmentation and increase of late apoptosis. The in vivo development of tumors following chemical carcinogenesis was significantly blunted by treatment with EMD638683.
EMD638683 promotes radiation-induced suicidal death of colon tumor cells in vitro and decreases the number of colonic tumors following chemical carcinogenesis in vivo.
血清和糖皮质激素诱导激酶SGK1最初是从乳腺肿瘤细胞中克隆出来的，在部分而非所有肿瘤中高表达。SGK1赋予多种肿瘤细胞生存能力。据此，SGK1基因敲除小鼠经化学致癌后结肠肿瘤数量减少。最近，一种高选择性的SGK抑制剂（EMD638683）已被研发出来。本研究探讨了EMD638683是否在体外影响结肠癌细胞的存活以及在体内对结肠肿瘤的发生发展产生影响。
结肠癌细胞（Caco-2）暴露于EMD638683，有无接受辐射（3 Gy），通过前向散射估计细胞体积，通过膜联蛋白V结合检测磷脂酰丝氨酸暴露情况，通过JC-9荧光检测线粒体膜电位，通过CaspGlow荧光素染色检测半胱天冬酶3活性，通过碘化丙啶染色检测DNA降解情况，以及通过膜联蛋白-V异硫氰酸荧光素和碘化丙啶双重染色检测晚期凋亡情况。在经化学致癌的野生型小鼠（腹腔注射20 mg/kg 1,2-二甲基肼，随后在饮用水中加入30 g/L合成葡聚糖硫酸钠进行三个周期，持续7天）中测定体内肿瘤生长情况。
EMD638683处理显著增强了辐射诱导的前向散射减少、磷脂酰丝氨酸暴露增加、线粒体膜电位降低、半胱天冬酶3活性增加、DNA片段化增加以及晚期凋亡增加。EMD638683处理显著抑制了化学致癌后肿瘤的体内生长。
EMD638683在体外促进辐射诱导的结肠肿瘤细胞自杀性死亡，并在体内减少化学致癌后结肠肿瘤的数量。
