PROGRESSION OF CHEMICAL INDUCED SKIN TUMORS

对化学诱导的小鼠皮肤肿瘤的初步研究表明， 在鳞状细胞癌（SCC）的肿瘤进展过程中， 变异型低分化肿瘤，称为梭形细胞癌 （SPCC），可以出现，其特征在于增强的侵袭性， 转移潜能 我们已经开发出了细胞系， 相同双相（SCC/SPCC）初级的SCC和SPCC组分 小鼠肿瘤，以便通过差异显示基因鉴定， 干预从SCC到SPCC的切换。 我们特别关注 与人类和大鼠同源的基因表达缺失 PACE 4在SCC细胞系中的表达及其在SPCC中的过度表达 细胞系 由于PACE 4是几种蛋白质加工酶之一， 称为前蛋白转化酶（PC），其中一些具有假定的作用 在激活癌症发展所必需的底物方面， 本申请旨在研究PC在肿瘤中的功能， 进展 要检验的中心假设是，PACE 4和 另一个PC，弗林蛋白酶通过激活特定的目标，如矩阵 金属蛋白酶（MMPs）增强SCC细胞的侵袭性，因此 构成了一系列事件的重要组成部分， 晚期恶性表型，在SPCC中达到顶峰。 为了达到这个目的，我们计划：1）调查是否 PACE 4表达是诱导的小鼠肿瘤的一个重要特征 化学致癌的方案，以及这种表达是否是 与增强的侵袭性/转移性行为和/或 分化; 2）确定弗林蛋白酶是否参与该过程 3）研究外源性表达对肿瘤进展的影响 PC cDNA对获得侵袭性/转移性表型的影响 乳头状瘤和低级别非转移性SCC细胞系; 4）研究 PC在培养系统中激活MMPs的作用，以及 在原发性肿瘤中; 5）确定 通过研究PC在人类SCC中的作用获得这些发现，6） 通过克隆启动对PC上调原因的研究， 测序PACE 4启动子区域并创建启动子-报告基因 转基因小鼠，以评估正常组织中的基因调控， 诱导SCC。

Preliminary studies on chemically-induced mouse skin tumors have shown that during tumor progression of squamous cell carcinomas (SCC), a variant poorly-differentiated neoplasm, called spindle cell carcinoma (SPCC), can arise that is characterized by enhanced invasiveness and metastatic potential. We have developed cell lines that correspond to the SCC and SPCC components of the same biphasic (SCC/SPCC) primary mouse tumor, in order to identify by differential display genes that intervene in the switch from SCC to SPCC. In particular, we focused on the absence of expression of a gene homologous to the human and rat PACE4 in the SCC cell line and its overexpression in the matched SPCC cell line. Since PACE4 is one of the several protein processing enzymes known as proprotein convertases (PCs), some of which have putative roles in activating substrates that are essential for cancer development, in this application we propose to investigate the function of PCs in tumor progression. The central hypothesis to be tested is that PACE4 and another PC, furin by activating specific targets such as matrix metalloproteinases (MMPs) enhance the invasiveness of SCC cells, thus constituting important components of the chain of events leading to an advanced malignant phenotype, culminating in the SPCC. In order to achieve this objective, we plan to: 1) investigate whether PACE4 expression is a significant feature of mouse tumors induced by protocols of chemical carcinogenesis and whether this expression is closely related to enhanced invasive/metastatic behavior and/or loss of differentiation; 2) determine whether furin participates in the process of tumor progression; 3) investigate the effect of exogenous expression of PC cDNAs on the acquisition of the invasive/metastatic phenotype of papilloma and low grade non-metastatic SCC cell lines; 4) investigate the role of PCs in the activation of MMPs in culture systems as well as in primary tumors; 5) determine the probable translational value of these findings by investigating the role of PCs in human SCCs and 6) initiate studies on the cause of PC upregulation by cloning and sequencing the PACE4 promoter region and create promoter-reporter transgenic mice to evaluate gene regulation in normal tissues and induced SCCs.