Analysis for machanisms invokved in ultraviolct B-light-induced apoptosis in cpidcrmal cells

本研究旨在探讨紫外线B光诱导表皮细胞凋亡的机制。理论背景是1）UV被认为是非黑素瘤性皮肤癌（包括鳞状细胞癌（SCC）、基底细胞癌（BCC））的潜在致癌物，2）众所周知UV有效地诱导表皮细胞（例如角质形成细胞和黑素细胞）的凋亡。基于这些关于表皮细胞凋亡的现有知识，我们认为，如果我们可以利用有关凋亡的知识来操纵治疗，如那些对癌症。因此，为了解决这个问题，我们首先集中在人工诱导黑色素瘤细胞凋亡。我们先前已经发现，在晚期黑素瘤细胞中，强烈表达CD 95配体（CD 95 L/APO-1 L/FasL）。由于几乎所有类型的细胞，包括免疫活性细胞，都表达CD 95（Maeda等，Br J Dermatol 1998 ; 139：198-206），黑色素瘤可以抵抗免疫活性细胞的侵袭。 ...更多信息 e细胞通过CD 95/CD 95 L交联诱导其凋亡。为了利用这些知识，我们首先感兴趣的是，当我们在黑素瘤细胞上引入CD 95表达时，我们是否可以诱导表达CD 95 L的黑素瘤细胞的凋亡。答案是肯定的，正如我们发表的，在表达CD 95 L的黑色素瘤上异位表达CD 95导致这些细胞的强烈凋亡。尽管上述研究清楚地表明了将CD 95引入CD 95 L+黑素瘤细胞的可能有效性，但我们应该知道黑素瘤CD 95 L何时被开启。因此，我们接下来使用患者标本分析了CD 95 L的表达，结果发现黑素瘤细胞，当从外部到达比3.5-mm更深时（对应于大约中间真皮），变得能够表达CD 95 L（Maeda等，J Dermatol 2001 ; 28：499-504）。本研究旨在通过CD 95的异位表达来确定未来治疗黑色素瘤的可行策略。除黑色素瘤外，基底细胞癌（BCC）是世界范围内最常见的皮肤肿瘤之一。由于BCC的发病机制尚不完全清楚，我们接下来关注这个问题。因此，我们将Wnt信号通路中的信号元件β-catenin作为研究对象，研究其在结肠癌发病机制中的作用。为了解决这个问题，我们对BCC标本进行了免疫染色，结果显示，在大约70%的BCC中观察到β-catenin的核转位，而其他皮肤病，如特应性皮炎、银屑病、鳞状细胞癌，均未在细胞核中产生阳性信号。由于该蛋白的核转位是参与癌变的必要条件，因此我们得出结论，b-连环蛋白参与了基底细胞癌的发病机制。需要进一步分析以确定哪些元件是导致β-连环蛋白核转位的原因。少

This research project was primarily designed to analyze mechanisms involved in ultraviolet B light (UV)-induced apoptosis of epidermal cells. The theoretical background was 1)UV is regarded as a potent carcinogen of non- melanomatous skin cancers, including squamous ell carcinoma (SCC), basal cell carcinoma (BCC), 2)UV is well known to effectively induce apoptosis of epidermal cells, such as keratinocytes and melanocytesl. Based on these so far available knowledge about apidermal cell apoptosis, we thought if we can use the knowlede regarding apoptosis to manipulate therapics, such as those against cancers. Therefore, to address this concern, we first focused on artificial induction of apoptosis of melanoma cells. We previously could chow that melanoma cells, in advanced stage, vigorously express CD95 ligand (CD95L/APO-1L/FasL). Since almost all types of cells including immunocompetent cells express CD95 (Maeda et al, Br J Dermatol 1998 ; 139 : 198-206), melanoma may counterattackimmun … More e cells by inducing their apoptosis via CD95/CD95L crosslinking. To employ this knowledge, we first were interested whether we could induce apoptosis of CD95L-expressing melanoma cells when we introduce expression of CD95 on melanoma cells. The answer was 'yes', as published by us that ectopic expression of CD95 on CD95L-expressing melanoma led to vigorous apoptosis of those cells. This implies future therapeutic uefulness of this strategy in melanoma thereapy.Although the above study clearly indicates the possible effectiveness of CD95 introduction of CD95L+melanoma cells, we should know when melanoma CD95L is turned on. Therefore, we next analysed using patients' specimens for expression of CD95L consequently, it was found that a melanoma cell, when reaches deeper than 3.5-mm from the outside (corresponding approximately middle dermis), becomes able to express CD95L (Maeda et al, J Dermatol 2001 ; 28 : 499-504). Together, we were able to identify the future feasible strategy to treat melanoma patients by ectopic expression of CD95.Besides melanoma, basal cell carcinoma (BCC) is one of the most frequently encountered dermatological neoplasms worldwide. Since pathegenesis of BCC is not completely clear yet, we next focused about this issue. Therefore, we focused β-catenin, a signaling element of Wnt-signaling pathway and reported to be involved in pathogenesis of colon cancers. To address this issue, we immunostained BCC specimens, revealing that nuclear translocation of β-catenin was observed in approximately 70% of BCC tested, while non of other dermatoses, such as atopic dermatitis, psoriasis, squamous cell carcinoma, gave rise to positive signal in muclei. Because nuclear translocation of this protein is a requisite condition to be involved in carcinogenesis, we concluded that b-catenin is involved in pathogenesis of BCC. Further analysis is required to identify which elements are causal to nuclear translocation of β-catenin. Less