TUMOR PROMOTERS & PROTEIN KINASE C IN CANCER METASTASIS

肿瘤促进剂佛波酯和细胞调节剂 升高细胞内二酰甘油，诱导蛋白激酶C 结合到质膜上，从而影响各种 细胞功能包括细胞黏附和胞吐作用。这些 Ca~(2+)调节功能在血液生成中的关键作用 转移。我们最初的观察显示出强烈的 膜结合蛋白激酶水平之间的相关性 C活性和转移能力的三个特征 表型稳定的B16小鼠黑色素瘤亚系 低(F1)、中(BL6)和高(F10)转移行为 促使本提案旨在调查 膜结合蛋白激酶C在血行转移中的作用 膜结合蛋白激酶C活性低的原因 在F1亚线上对比F10将进行测试。基于 观察到12-0十四酰佛波醇-13-乙酸酯(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，减少转移，这项研究 将调查生理调节剂和 药理制剂，它调节膜结合 蛋白激酶C，与血行转移有关。转移将会是 通过计算出现的肺结节数目来评价 尾静脉注射处理细胞3周后。这些细胞将 也可以测试它们在体外与内皮细胞的附着情况 单层和基底膜及其体内早期(3h) 肺滞留用于评估细胞黏附的改变 由蛋白激酶C介导。这项研究将确定 蛋白激酶C和磷酸化的膜靶蛋白 检测它们对内皮细胞和基底细胞的亲和力 细胞膜被改变。最后，蛋白激酶C的作用机制 延长TPA治疗的失活将通过以下方式解决 特别关注蛋白水解性失活的作用 CaPain(钙激活的蛋白水解酶)和氧化失活 活性氧物种。某些药物，包括抗癌药物 已知会产生氧自由基的药物将是 测试它们使蛋白激酶C失活和抑制的能力 转移。这项研究还将评估 肿瘤促进剂在肿瘤的血源性扩散中的作用。

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.