|Budget Amount *help
¥3,300,000 (Direct Cost: ¥3,300,000)
Fiscal Year 2001: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥1,100,000 (Direct Cost: ¥1,100,000)
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
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