Twist1 as a Target for Prevention and Treatment of Cutaneous Squamous Cell Carcinoma

项目总结 拟议研究的总体目标是了解Twist1在皮肤鳞状细胞中的作用 肿瘤(CSCC)，并开发靶向Twist1的新方法来预防和治疗这种疾病 重要的疾病。Twist1是一种参与上皮-间充质转化和肿瘤的转录因子 一些上皮性癌症的进展和转移。在我们实验室之前的研究中，我们发现 TPA促皮肤肿瘤过程中角质形成细胞的增殖需要Twist1 提示在皮肤癌发生过程中的早期作用，除了在癌症进展和 转移。这些早期的研究表明，Twist1调节了G1-S期细胞周期蛋白的水平。 此外，Twist1还可以调节p53和p21的功能。到目前为止，Twist1对UV的影响 皮肤癌的发生还没有被研究过，因此证明Twist1也起作用是很重要的 在紫外线皮肤癌的发生中起关键作用。在新的初步实验中，我们发现Twist1在 角质形成细胞导致角质形成细胞分化。此外，Twist1在小鼠基底角质形成细胞中的缺失 小鼠在体表皮导致隆起区角质形成细胞干细胞(KSCs)的变化，包括迁移 KSCS离开凸起区域。这些发现表明，Twist1可能在调节 角质形成细胞分化是KSC动态平衡所必需的。在额外的初步实验中，我们有 发现在Twist1缺陷角质形成细胞中Ovol1的表达显著上调，这可能是原因之一 用于推动差异化。此外，我们还发现，哈拉明，一种天然存在的化合物 据报道，通过促进Twist1的降解来抑制Twist1，诱导角质形成细胞和上皮性细胞分化 Ovol1以类似于在Twist1 KO小鼠的表皮中看到的方式。在本提案中，我们将测试 假设Twist1通过维持两者之间的平衡在紫外线诱导的CSCC中发挥关键作用 表皮角质形成细胞的增殖和分化，包括KSCs通过调节 Ovol1和靶向Twist1将有效地抑制紫外线诱导的CSCC。具体目标如下：一) 进一步研究Twist1在调节角质形成细胞和KSCs增殖和分化中的作用；ii) 研究角质形成细胞特异性缺失Twist1基因对紫外线诱发皮肤癌的影响；iii) 确定Ovol1作为Twist1下游效应分子在调节肿瘤细胞增殖和分化中的作用 角质形成细胞和角质形成细胞(KSC)进一步评估新型Twist1抑制剂三尖杉酯碱预防紫外线损伤的能力 诱发皮肤癌。拟议研究的完成将进一步阐明Twist1在 角质形成细胞和KSC的增殖分化及其在宫颈鳞癌发生发展中的作用 皮肤肿瘤的发展阶段。将Twist1确定为皮肤癌发生的关键早期参与者可能 导致预防和治疗CSCC的新方法。新型预防制剂的开发 和/或本赠款申请中建议的治疗可能会导致此类药物迅速进入临床。

PROJECT SUMMARY The overall goal of the proposed research is to understand the role of Twist1 in cutaneous squamous cell carcinoma (cSCC) and to develop novel approaches for targeting Twist1 for prevention and treatment of this important disease. Twist1 is a transcription factor involved in epithelial-mesenchymal transition and cancer progression and metastasis in a number of epithelial cancers. In previous studies from our laboratory, we found that Twist1 was required for proliferation of keratinocytes during the process of skin tumor promotion by TPA suggesting a role early in the process of skin carcinogenesis in addition to its role in cancer progression and metastasis. These earlier studies showed that Twist1 regulated levels of G1-S-phase cell cycle proteins. Furthermore, Twist1 was shown to regulate the function of p53 and p21. To date, the impact of Twist1 on UV skin carcinogenesis has not been studied and therefore it is important to demonstrate that Twist1 also plays critical role in UV skin carcinogenesis. In new preliminary experiments, we have found that deletion of Twist1 in keratinocytes leads to keratinocyte differentiation. Furthermore, deletion of Twist1 in basal keratinocytes of mouse epidermis in vivo leads to changes in bulge-region keratinocyte stem cells (KSCs), including migration of KSCs out of the bulge region. These findings suggest that Twist1 may play an important role in regulating keratinocyte differentiation and be required for KSC homeostasis. In additional preliminary experiments, we have found that Ovol1 expression is significantly upregulated in Twist1 deficient keratinocytes and may be responsible for driving differentiation. Furthermore, we have also found that Harmine, a naturally occurring compound reported to inhibit Twist1 by facilitating its degradation, induces differentiation in keratinocytes and upregulates Ovol1 in a manner similar to that seen in epidermis of Twist1 KO mice. In this proposal, we will test the hypothesis that Twist1 plays a critical role in UV-induced cSCC by maintaining the balance between proliferation and differentiation of epidermal keratinocytes, including KSCs via regulation of the levels of Ovol1 and that targeting Twist1 will effectively inhibit UV-induced cSCC. The specific aims are as follows: i) To further examine the role of Twist1 in regulating proliferation and differentiation of keratinocytes and KSCs; ii) To examine the impact of keratinocyte specific deletion of Twist1 on UV-induced skin carcinogenesis; iii) Determine the role of Ovol1 as a downstream effector of Twist1 in regulating proliferation and differentiation of keratinocytes and KSCsand iv) Further evaluate the ability of Harmine, a novel Twist1 inhibitor, to prevent UV- induced skin carcinogenesis. Completion of the proposed studies will further elucidate the role of Twist1 in keratinocyte and KSC proliferation and differentiation and its role in development of cSCC, especially in the early stages of skin tumor development. Identification of Twist1 as a key early player in skin cancer development could lead to novel approaches for the prevention and treatment of cSCC. Development of novel agents for prevention and/or treatment as proposed in this grant application could lead to rapid translation of such agents into the clinic.