Mechanism of Chemoprevention Action and SAR of a Tetrahydroisoquinoline Riboside

描述（由申请人提供）： 具有结构-活性关系（SAR）的促进剂，其指向除NT抑制以外的某些机制。例如，在JB 6 P+致癌模型中作为抗肿瘤促进剂测试的新型四氢异喹啉核苷NT抑制剂中，关于抗促进活性的效力的相对顺序为：化合物23 >化合物3 >化合物4，而NT抑制效力顺序相反，其中化合物4最有效（Ki = 0.45 nM），其次是化合物3（Ki = 15 nM），然后是化合物23，最不有效（Ki = 300 nM）。在用化合物23进一步研究后，我们已经表明，除了抑制TPA诱导的致瘤转化之外，它还抑制TPA诱导的AP-1转录因子活化，这已经显示在JB 6小鼠表皮细胞致癌模型中以及在许多其他体外和体内致癌过程中，在TPA诱导的肿瘤促进中具有主要作用。因此，在本申请中，我们提出开始研究化合物23的作用机制，以及进行抗肿瘤促进SAR和在体内小鼠皮肤致癌模型中测试化合物的癌症化学预防潜力。具体目标是：1）合成和测试化合物23的新的芳族和杂环类似物，2）研究对AP-1 DNA结合和MAP激酶信号传导途径的干扰，其可能解释化合物的可能的AP-1依赖性抗肿瘤促进活性，和3）在体内小鼠皮肤致癌模型中评价来自Aim 2的最佳化合物。我们建立的AP-1-SEAP JB 6报告细胞将用于SAR及其机制的体外研究。我们将使用AP-1-SEAP报告基因和锚定非依赖性细胞生长克隆转化测定来测试待合成活性的新化合物的潜在化学预防活性。将分析AP-1 DNA结合、蛋白激酶C的干扰以及已知位于AP-1上游的促分裂原活化蛋白激酶（MAPK）ERK、p38和JNK的作用。SENCAR小鼠皮肤两阶段致癌模型将用于评估这类化合物的体内抗肿瘤促进活性，以尝试鉴定用于临床前优化的潜在先导化合物。这项研究计划的成功可能会导致新的有前途的皮肤癌化学预防剂的鉴定。

DESCRIPTION (provided by applicant): Promotion agents with a structure-activity relationship (SAR) that points to some mechanism(s) other than NT inhibition. For example, among novel tetrahydroisoquinoline riboside NT inhibitors tested as anti-tumor promotion agents in the JB6 P+ carcinogenesis model, the relative order of potency with regard to anti-promotion activity was: Compound 23 > Compound 3 > Compound 4, whereas the NT inhibitory potency order was the opposite, with Compound 4 being the most potent (Ki = 0.45 nM) followed by Compound 3 (Ki = 15 nM) and then followed by Compound 23, the least potent (Ki = 300 nM). Upon further investigation with Compound 23, we have shown that in addition to inhibiting TPA-induced tumorigenic transformation, it also inhibits TPA-induced AP-1 transcription factor activation, which has been shown to have a major role in TPA-induced tumor promotion in the JB6 mouse epidermal cell carcinogenesis model, as well as in many other in vitro and in vivo carcinogenesis processes. Thus, in this application, we propose to initiate an investigation of the mechanisms of action of compound 23, as well as conduct antitumor promotion SAR and test the compounds' cancer chemopreventive potential in an in vivo mouse skin carcinogenesis model. The specific aims are: 1) to synthesize and test new aromatic and heterocyclic analogs of Compound 23, 2) to investigate interference with AP-1 DNA binding, and MAP kinase signaling pathways that might account for the possible AP-1-dependent antitumor promotion activity of the compounds, and 3) to evaluate the best compound from Aim 2 in an in vivo mouse skin carcinogenesis model. AP-1-SEAP JB6 reporter cells created by us will be used for the in vitro investigations of SAR and mechanism. We will use the AP-1-SEAP reporter and anchorage independent cell growth clonogenic transformation assays to test the potential chemopreventive activity of new compounds to be synthesized activity. Interference with AP-1 DNA binding, protein kinase C, as well as the role of the mitogen-activated protein kinases (MAPKs) ERK, p38 and JNK, known to be upstream of AP-1, will be analyzed. The SENCAR mouse skin two-stage carcinogenesis model will be used to assess the in vivo anti-tumor promotion activity of this class of compounds in attempts to identify potential lead compounds for preclinical optimization. The success of this research program may lead to the identification of novel promising agents for skin cancer chemoprevention.