title: Potentiation of UVB-induced apoptosis by novel phytosphingosine derivative, tetraacetyl phytosphingosine in HaCaT cell and mouse skin.
abstract: Inappropriate apoptosis results in the epidermal hyperplasia as in psoriasis and UVB irradiation has been successfully used to treat this kind of skin disorders. Previously, we reported that the novel phytosphingosine derivative, tetraacetyl phytosphingosine (TAPS) induced apoptosis in HaCaT cells. This study examined the effect of UVB irradiation and/or TAPS on the induction of apoptosis in HaCaT. 10 mJ/cm2 of UVB irradiation or 10 microM of TAPS alone exhibited weak cytotoxicity but co-treatment of UVB and TAPS synergistically enhanced the cytotoxicity and apoptosis in HaCaT. The cells treated with UVB and TAPS showed much higher levels of cleaved caspase-3, -8, -9 and Bax than with UVB or TAPS alone, whereas Bcl-2 level was decreased by co-administration of UVB and TAPS. In hairless mice, co-treatment of UVB and TAPS synergistically increased apoptosis, as shown in the HaCaT co-treated with UVB and TAPS. Furthermore, UVB irradiation caused an increase of apoptotic cells in the epidermis and the TAPS-treated mice showed an increase of apoptotic cells in the dermis as well as in the epidermis. These results suggest that the TAPS co-treatment synergistically increases the level of UVB-induced apoptosis via caspase activation by regulating the level of pro-apoptotic Bax and anti-apoptotic Bcl-2.
authors.affiliation: Department of Dermato-Immunology, The Catholic University of Korea, 505 Banpo-dong, Seocho-gu, Seoul, South Korea 137-040.
authors.forename: H J
authors.initials: HJ
authors.lastname: Kim
authors.forename: S-Y
authors.initials: SY
authors.lastname: Kang
authors.forename: S J
authors.initials: SJ
authors.lastname: Kim
authors.forename: S H
authors.initials: SH
authors.lastname: Kim
authors.forename: T-Y
authors.initials: TY
authors.lastname: Kim
mesh_terms: D000107:Acetylation; D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000528:radiation effects; D015153:Blotting, Western; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases / Q000378:metabolism; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects; D045304:Cytochromes c / Q000378:metabolism; D020405:Dermis / Q000166:cytology / Q000187:drug effects / Q000528:radiation effects; D000078404:Epidermal Cells; D004817:Epidermis / Q000187:drug effects / Q000528:radiation effects; D005434:Flow Cytometry; D006801:Humans; D020287:In Situ Nick-End Labeling; D015603:Keratinocytes / Q000187:drug effects* / Q000378:metabolism / Q000528:radiation effects; D051379:Mice; D008812:Mice, Hairless; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D012867:Skin / Q000166:cytology / Q000187:drug effects* / Q000528:radiation effects; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000737:chemistry / Q000494:pharmacology; D014466:Ultraviolet Rays; D051028:bcl-2-Associated X Protein
chemical_list: C494826:BAX protein, human; C494827:Bax protein, mouse; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D045304:Cytochromes c; C505407:CASP3 protein, human; C505530:CASP8 protein, human; C506433:CASP9 protein, human; C505409:Casp3 protein, mouse; C505526:Casp8 protein, mouse; C506434:Casp9 protein, mouse; D053148:Caspase 3; D053181:Caspase 8; D053453:Caspase 9; D020169:Caspases; C012491:phytosphingosine; D013110:Sphingosine