CANCER PREVENTION & IMBALANCE IN PROTEIN PHOSPHORYLATION

这项研究的长期目标是验证一个假设，即氧化剂 可能引起蛋白质磷酸化系统的失衡， 化学预防性抗氧化剂可以抵消该过程。 氧化剂有 作为肿瘤促进的重要介质， 蛋白激酶C（PKC）和蛋白质 磷酸酶（PP）1和2A已成为肿瘤促进剂的受体 在别人家里所知的 尽管如此，这些调解人之间的相互联系是 不太了解。 我们的初步研究显示， PP2A易氧化失活，氧化剂促肿瘤 可能诱导PKC、PP1/PP2A的区室化和失衡 系统 相反，化学预防性抗氧化剂可能会破坏交叉- 氧化剂和肿瘤促进剂受体之间的对话。 这些 将用C3H/10T1/2细胞系和体外细胞培养物进行研究。 转型模式。 主要重点是了解直接 以及氧化剂对PKC/PP系统的间接作用， 抗氧化剂的直接作用（间接作用）。 变形- 相关研究将限于鸟氨酸的诱导 脱羧酶、c-fos、c-myc和转化灶的体外评分。 第一个目的是确定氧化剂肿瘤促进剂H2O2， 过氧化苯甲酰和佛波酯诱导的氧化剂可以诱导 PKC/PP失衡或区室化。 然后， 了解PKC/PP失衡如何影响上述结果 提到了与转型有关的事件。 第二个目标是确定 非硫化学预防剂，类胡萝卜素（番茄红素， β-胡萝卜素）、维生素E和鞣花酸来抵消氧化剂 对PKC、PP1和PP2A的影响。 第三个目标是扩展这些研究 有机硫化合物二烯丙基硫醚和奥替普拉（二硫硫醇酮） 为了评估硫剂的抗氧化作用是否不同于 不含硫剂。 最终目的是了解 化学预防剂的相互作用， 对抗肿瘤促进剂。 硒，维生素E， 维生素C和二烯丙基硫将被研究。 的结果予以 这些研究可能有助于进一步了解 癌症化学预防

The long term goal of this study is to test a hypothesis that oxidants may induce an imbalance in protein phosphorylation systems, and chemopreventive antioxidants may counteract this process. Oxidants have emerged as important mediators of tumor promotion in one era of carcinogenesis research while protein kinase C (PKC) and protein phosphatase (PP) 1 and 2 A have emerged as receptors for tumor promoters in another. Nonetheless, the interlink between these mediators is poorly understood. Our preliminary studies revealed that oxidant tumor PP2A are susceptible to oxidative inactivation, oxidant tumor promoters may induce compartmentalization and imbalance in the PKC, PP1/PP2A system. Conversely, chemopreventive antioxidants may disrupt the cross- talk between the oxidants and the receptors for tumor promoters. These studies will be carried out with the C3H/10T1/2 cell line and an in vitro model of transformation. The primary focus is to understand the direct and indirect actions of oxidants that influence the PKC/PP system and its direct counteraction by antioxidants (indirect actions). Transformation- related studies will be restricted to induction of ornithine decarboxylase, c-fos, c-myc and in vitro scoring of the transformed foci. The first aim is to determine whether the oxidant tumor promoters H202, benzoyl peroxide and phorbol ester-induced oxidants can induce an imbalance or compartmentalization in PKC/PP. Then, studies are extended to understand how the imbalance in PKC/PP could affect the above mentioned transformation-related events. The second aim is to determine the abilities of nonsulfur chemopreventive agents, carotenoids (lycopene, Beta-carotene), vitamin E, and ellagic acid to counteract the oxidant effects on PKC, PP1, and PP2A. The third aim is to extend these studies to the organosulfur compounds diallysulfide and oltipraz (dithiolthiones) to assess whether the antioxidant actions of sulfur agents differ from that of nonsulfur agents. The final aim is to understand the interactions of chemopreventive agents that are effective in counteracting tumor promoters. The combination of selenium, vitamin E, Vitamin C, and diallylsulfide will be studied. The results of these studies may further help understand the molecular mechanisms involved in cancer chemoprevention.