TUMOR PROMOTERS & PROTEIN KINASE C IN CANCER METASTASIS

肿瘤促进剂佛波醇酯和细胞调节剂， 升高细胞内甘油二酯，诱导蛋白激酶C 与质膜结合，从而影响各种 细胞功能包括细胞粘附和胞吐作用。 这些 Ca 2+调节功能在造血干细胞中发挥关键作用 转移 我们最初的观察显示 膜结合蛋白激酶水平与 C活性和转移能力在三个良好表征的 表型稳定的B16鼠黑色素瘤亚系， 低（F1）、中等（BL 6）和高（F10）转移行为 促使本建议旨在调查的作用， 膜结合蛋白激酶C与血行转移 膜结合蛋白激酶C活性低的原因 在F1亚系比较F10将被测试。 基于 观察到12-0十四酰基佛波醇-13-乙酸酯（TPA）（1 h）-处理刺激蛋白激酶的膜结合 C和增加转移，而TPA（24小时）治疗 使蛋白激酶C失活并减少转移， 将研究生理调节剂的作用， 药理学试剂，其调节膜缔合， 蛋白激酶C对血行转移的影响。 转移将是 通过计数出现的肺结节数量进行评估 尾静脉注射处理细胞后3周。 这些细胞将 还测试了它们在体外与内皮细胞的附着 单层和基底膜及其早期（3 h） 肺滞留，以评估细胞粘附的改变 由蛋白激酶C介导。 该研究将确定 被蛋白激酶C磷酸化的膜靶蛋白， 检测它们对内皮和基底的亲和力 膜发生了变化。 最后，蛋白激酶C的机制 长期TPA处理的灭活将通过以下方法解决： 特别注意蛋白水解失活的作用 通过钙蛋白酶（Ca 2+激活蛋白酶）和氧化失活， 活性氧 某些药物，包括抗癌药物 已知会产生氧自由基的药物， 测试了它们抑制蛋白激酶C和抑制 转移 本研究还将评估以下方面的额外作用： 在癌症的血行扩散中的肿瘤促进剂。

Tumor promoter phorbol esters, and cellular regulators which elevate intracellular diacylglycerol, induce protein kinase C association to the plasma membrane and thereby influence various cellular functions including cell adhesion and exocytosis. These Ca2+-regulated functions play key roles in hematogenous metastasis. Our original observations showing a strong correlation between the levels of membrane-bound protein kinase C activity and metastatic ability in three well characterized phenotypically stable sublines of B16 murine melanoma exhibiting low (F1), intermediate (BL6) and high (F10) metastatic behaviour prompted the present proposal designed to investigate the role of membrane-bound protein kinase C in hematogenous metastasis. The reasons why membrane-bound protein kinase C activity is low in the F1 subline compared F10 will be tested. Based on observations that 12-0 tetradecanoylphorbol-13-acetate (TPA) (1 h)-treatment stimulates membrane-association of protein kinase C and increases metastasis whereas TPA (24 h) treatment inactivates protein kinase C and decreases metastasis, this study will investigate the effects of physiological regulators and pharmacological agents, which modulate membrane association of protein kinase C, on hematogenous metastasis. Metastasis will be evaluated by counting the number of pulmonary nodules appearing 3 weeks after tail vein injection of treated cells. These cells will also be tested for their in vitro attachment to endothelial monolayers and basement membranes and their early (3 h) in vivo pulmonary retention to assess alterations in cell adhesion mediated by protein kinase C. The study will identify the membrane target proteins phosphorylated by protein kinase C and examine whether their affinity for endothelium and basement membranes is altered. Finally, the mechanism of protein kinase C inactivation with prolonged TPA treatment will be addressed with specific attention placed on the roles of proteolytic inactivation by calpain (Ca2+-activated protease) and oxidative inactivation by reactive oxygen species. Certain agents including anticancer drugs that are known to generate oxygen free radicals will be tested for their ability to inactivate protein kinase C and inhibit metastasis. This study also will evaluate the additional role of tumor promoters in the hematogenous spread of cancer.