Progression of Chemical Induced Skin Tumors

描述（由申请人提供）：PACE4是我们实验室研究的一种蛋白转化酶（PC），在金属蛋白酶和其他癌症相关底物的加工中起重要作用。我们发现PACE4在化学致癌方案诱导的高级别小鼠皮肤鳞状细胞癌中过表达。此外，当在小鼠皮肤源性角质形成细胞中过度表达时，它能够增加细胞侵袭性。在本提案中，我们将使用转基因小鼠模型和化学诱导的皮肤肿瘤，试图在体内证明PCs有助于肿瘤发生和进展的假设，以及体内PC抑制将导致皮肤肿瘤形成和/或侵袭性恶性表型的减少或消失。此外，我们将尝试证明哪些PC底物，一旦在体内激活，将显著促进肿瘤生长和进展的过程。本文主要研究以下三个方面：1)利用角蛋白5启动子控制PACE4的转基因小鼠模型（K5-PACE4小鼠），采用化学致癌方案确定PACE4组织特异性过表达对不同阶段皮肤癌变的影响。我们预计这些转基因动物将表现出对致癌的易感性增加。2)利用转基因模型，在体内评价PCs的抑制作用。我们将通过在表皮中产生表达基于蛋白的PC抑制剂α -1 PDX （PDX）的转基因小鼠来建立遗传转移方法的可行性。这些小鼠应该能抵抗化学致癌和/或肿瘤进展，并能中和PACE4的作用。此外，我们将使用已知的PC抑制剂，如氯甲基酮，局部应用于K5-PACE4小鼠的皮肤，以评估pace4诱导的皮肤化学致癌易感性的逆转。3)为了确定肿瘤发生的关键体内PC底物，我们建议将K5-PACE4小鼠与其他针对皮肤表达PACE4底物的转基因动物（如IGF-1、tgf - β和MT2-MMP）杂交。这种方法将在加速皮肤肿瘤发展的过程中建立各自底物激活的体内层次结构。

DESCRIPTION (provided by applicant): PACE4, a proprotein convertase (PC) studied in our laboratory has a significant role in the processing of metalloproteases and other cancer-related substrates. We have found that PACE4 is overexpressed in high grade murine skin squamous cell carcinomas induced by chemical carcinogenesis protocols. In addition, when overexpressed in mouse skin-derived keratinocytes it is able to increase cell invasiveness. In the present proposal, using transgenic mouse models and chemically-induced skin tumors, we will attempt to prove in vivo, the hypothesis that PCs contribute to tumor development and progression and that in vivo PC inhibition will result in the decrease or absence of skin tumor formation and/or aggressive malignant phenotypes. In addition, we will attempt to demonstrate which of the PC substrates, once activated in vivo, will contribute significantly to the process of tumor growth and progression. The following three aims are to be addressed: 1) Using a transgenic mouse model in which PACE4 is under the control of the keratin 5 promoter (K5-PACE4 mice), chemical carcinogenesis protocols will be used to determine the effect of PACE4 tissue specific overexpression on different stages of skin carcinogenesis. We expect that these transgenic animals will exhibit an increased susceptibility to carcinogenesis. 2) Using the transgenic models, inhibitors of PCs will be evaluated in vivo. We will establish the feasibility of a genetic transfer approach by generating transgenic mice expressing the protein-based PC inhibitor alpha-1 PDX (PDX) in the epidermis. These mice should be resistant to chemical carcinogenesis and/or tumor progression and should neutralize the effects of PACE4. In addition, we will use known PC inhibitors such as chloromethyl ketone, applied topically to the skin of K5-PACE4 mice to evaluate the reversal of the PACE4-induced susceptibility to skin chemical carcinogenesis. 3) In order to determine the critical in vivo PC substrates for cancer development, we propose to cross K5-PACE4 mice with other transgenic animals expressing PACE4 substrates targeted to the skin such as IGF-1, TGF-beta and MT2-MMP. This approach will establish the in vivo hierarchy of the respective substrate activation in the acceleration of skin tumor development.