Couldwell W T, Law R E, Hinton D R, Gopalakrishna R, Yong V W, Weiss M H
Department of Neurological Surgery, University of Southern California School of Medicine, Los Angeles, USA.
Acta Neurochir Suppl. 1996;65:22-6. doi: 10.1007/978-3-7091-9450-8_8.
The present study was undertaken to explore the role of the Protein Kinase C (PKC) signal transduction system in growth regulation of pituitary adenomas. Primary tumor cultures were plated from fresh surgical tumor specimens. The PKC inhibitors Staurosporine and Tamoxifen were added at varying dosages to the cell cultures. Measurements of cell proliferation were performed by [3H]-thymidine uptake and the [3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H tetrazolium bromide] (MTT) assay. After a 48 h treatment period, both [3H]-thymidine uptake and absorbance on the MTT assay decreased in a dose-related manner in both the staurosporine and tamoxifen-treated cultures (IC50 of 10 nM and 30 microM respectively). Direct measurement of PKC activity using an in vitro assay revealed very high activity (range of 1465-5708 pmol/min/mg protein; within the range previously published for malignant glioma specimens) in 12 frozen specimens of pituitary adenomas (9 nonfunctional adenomas, 1 prolactinoma, 1 gonadotrophin-secreting and 1 corticotroph-secreting adenoma). In contrast, PKC activity measured in normal adenohypophysis was comparatively very low. These data indicate that pituitary adenoma cells display high PKC activity and are sensitive to growth inhibition by PKC inhibitors. These data suggest a role for the PKC system in regulating pituitary tumor growth, which may have implications for future therapy of these tumors.
本研究旨在探讨蛋白激酶C（PKC）信号转导系统在垂体腺瘤生长调控中的作用。从新鲜手术肿瘤标本中接种原代肿瘤培养物。将不同剂量的PKC抑制剂星形孢菌素和他莫昔芬添加到细胞培养物中。通过[3H] - 胸腺嘧啶核苷摄取和[3 - （4,5 - 二甲基 - 2 - 噻唑基） - 2,5 - 二苯基 - 2H溴化四氮唑]（MTT）法进行细胞增殖测量。在48小时的处理期后，在星形孢菌素和他莫昔芬处理的培养物中，[3H] - 胸腺嘧啶核苷摄取和MTT法的吸光度均呈剂量相关下降（IC50分别为10 nM和30 μM）。使用体外测定法直接测量PKC活性，发现在12例垂体腺瘤冷冻标本（9例无功能腺瘤、1例催乳素瘤、1例促性腺激素分泌腺瘤和1例促肾上腺皮质激素分泌腺瘤）中活性非常高（范围为1465 - 5708 pmol/分钟/毫克蛋白；在先前发表的恶性胶质瘤标本范围内）。相比之下，在正常腺垂体中测量的PKC活性相对非常低。这些数据表明垂体腺瘤细胞显示出高PKC活性，并且对PKC抑制剂的生长抑制敏感。这些数据提示PKC系统在调节垂体肿瘤生长中起作用，这可能对这些肿瘤的未来治疗有影响。
