Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America.
PLoS One. 2010 Nov 15;5(11):e13973. doi: 10.1371/journal.pone.0013973.
Cysteine protease cathepsins are important in extracellular matrix protein degradation, cell apoptosis, and angiogenesis. Mice lacking cathepsins are protected from tumor progression in several animal models, suggesting that the regulation of cathepsin activities controls the growth of various malignant tumors.
We tested the role of cathepsins using a mouse model of multistage epithelial carcinogenesis, in which the human keratin-14 promoter/enhancer drove the expression of human papillomavirus type 16 (HPV16) early region E6/E7 transgenes. During the progression of premalignant dysplasia, we observed increased expression of cysteine protease cathepsin S, but concomitantly reduced expression of cathepsin endogenous inhibitor cystatin C in the skin tissue extract. Absence of cystatin C in these transgenic mice resulted in more progression of dysplasia to carcinoma in situ on the face, ear, chest, and tail. Chest and ear skin extract real time PCR and immunoblot analysis, mouse serum sample ELISA, tissue immunohistological analysis, and tissue extract-mediated in vitro elastinolysis and collagenolysis assays demonstrated that cystatin C deficiency significantly increased cathepsin expression and activity. In skin from both the chest and ear, we found that the absence of cystatin C reduced epithelial cell apoptosis but increased proliferation. From the same tissue preparations, we detected significantly higher levels of pro-angiogenic laminin 5-derived γ2 peptides and concurrently increased neovascularization in cystatin C-deficient mice, compared to those from wild-type control mice.
Enhanced cathepsin expression and activity in cystatin C-deficient mice contributed to the progression of dysplasia by altering premalignant tissue epithelial proliferation, apoptosis, and neovascularization.
半胱氨酸蛋白酶组织蛋白酶在细胞外基质蛋白降解、细胞凋亡和血管生成中起着重要作用。几种动物模型中缺乏组织蛋白酶的小鼠免受肿瘤进展的影响，这表明组织蛋白酶活性的调节控制着各种恶性肿瘤的生长。
我们使用多阶段上皮癌发生的小鼠模型来测试组织蛋白酶的作用，其中人角蛋白 14 启动子/增强子驱动人乳头瘤病毒 16（HPV16）早期区域 E6/E7 转基因的表达。在癌前发育不良的进展过程中，我们观察到皮肤组织提取物中半胱氨酸蛋白酶组织蛋白酶 S 的表达增加，但同时内源性组织蛋白酶抑制剂胱抑素 C 的表达减少。这些转基因小鼠中胱抑素 C 的缺失导致面部、耳朵、胸部和尾巴的发育不良更倾向于原位癌。胸部和耳部皮肤提取物实时 PCR 和免疫印迹分析、小鼠血清样本 ELISA、组织免疫组织化学分析以及组织提取物介导的体外弹性溶解和胶原蛋白溶解测定表明，胱抑素 C 缺乏显著增加了组织蛋白酶的表达和活性。在胸部和耳部皮肤中，我们发现胱抑素 C 的缺失减少了上皮细胞凋亡，但增加了增殖。从相同的组织制备中，我们发现缺乏胱抑素 C 的小鼠中，促血管生成的层粘连蛋白 5 衍生的 γ2 肽水平显著升高，同时新血管生成增加，与野生型对照小鼠相比。
胱抑素 C 缺乏的小鼠中增强的组织蛋白酶表达和活性通过改变癌前组织上皮细胞的增殖、凋亡和新血管生成，促进了发育不良的进展。
