Id proteins in UV-mediated keratinocyte apoptosis

描述(申请人提供)：人类最常见的恶性肿瘤是皮肤癌，其发病率接近所有其他癌症亚型的总和。人类乳头瘤病毒(HPV)和紫外线(UV)照射都是这种疾病的危险因素。HPV的永生化可能是癌症发生的早期阶段，而紫外线可能通过诱导进一步的突变和选择致癌细胞来诱导后续事件。与载体转导或早期传代(P7)的E6/7细胞相比，HPV-16E6/7永生化的人角质形成细胞对UVB诱导的细胞凋亡非常敏感。DNA微阵列分析显示，在监测的16,000个基因中，ID蛋白家族的三个成员在UVB照射后显示出显著的变化；每个ID在原代细胞和永生化细胞中受到紫外线的不同调节。ID蛋白在多种其他细胞类型的分化、凋亡和肿瘤发生中发挥重要作用。因此，这些特定的目的将检验ID基因在细胞培养和移植的人表皮中对急性UVB照射诱导的角质形成细胞的凋亡和分化起核心作用的假设。 具体目的I将研究在原发和永生化的HfK中负责Id2和Id3差异调控的遗传元件。 特定目的II将描述Id2和Id3在调节人角质形成细胞凋亡中的作用。基因和细胞类型特异性反应的机制(S)将通过调查优先与ID2和ID3相互作用的因素来研究。 特殊目的III将从过度表达Id2或Id3的角质形成细胞中产生移植的人类表皮，以检测对UVB或局部致癌物的短期(分化和凋亡)和长期(转化)反应。

DESCRIPTION (provided by applicant): The most common malignancy occurring in humans is skin cancer, with an incidence that approaches that of all other cancer subtypes combined. Both human papillomavirus (HPV) and ultraviolet (UV) irradiation are risk factors for this disease. Immortalization by HPV may be an early stage in carcinogenesis, while UV may induce subsequent events both by inducing further mutations, as well as selecting for tumorigenic cells. HPV-16 E6/7-immortalized human keratinocytes were exquisitely sensitive to UVB-induced apoptosis compared to either vector-transduced or early passage (p7) E6/7 cells. DNA microarray analysis showed that, out of 16,000 genes monitored, three members of the Id protein family exhibit significant changes following UVB exposure; each Id was differentially regulated by UV in primary versus immortalized cells. Id proteins play important roles in differentiation, apoptosis, and tumorigenesis in a variety of other cell types. The Specific Aims will therefore test the hypothesis that Id genes play a central role in modulating keratinocyte apoptosis and differentiation induced by acute UVB exposure both in cell culture and grafted human epidermis. Specific Aim I will examine the genetic elements that are responsible for the differential regulation of Id2 and Id3 in primary and immortalized HFK. Specific Aim II will delineate the roles of Id2 and Id3 in the regulation of apoptosis in human keratinocytes. The mechanism(s) of the gene- and cell-type specific response will be studied by investigating the factors that interact preferentially with Id2 and Id3. Specific Aim III will generate a grafted human epidermis derived from keratinocytes that overexpress Id2 or Id3 to examine both the short-term (differentiation and apoptosis) and long-term (transformation) responses to UVB or topical carcinogens.