Raised expression of the antiapoptotic protein ped/pea-15 increases susceptibility to chemically induced skin tumor development.
ped/pea-15 is a cytosolic protein performing a broad antiapoptotic function. We show that, upon DMBA/TPA-induced skin carcinogenesis, transgenic mice overexpressing ped/pea-15 (Tg(ped/pea-15)) display early development of papillomas and a four-fold increase in papilloma number compared to the nontransgenic littermates (P<0.001). The malignant conversion frequency was 24% for the Tg(ped/pea-15) mice and only 5% in controls (P<0.01). The isolated application of TPA, but not that of DMBA, was sufficient to reversibly upregulate ped/pea-15 in both untransformed skin and cultured keratinocytes. ped/pea-15 protein levels were also increased in DMBA/TPA-induced papillomas of both Tg(ped/pea-15) and control mice. Isolated TPA applications induced Caspase-3 activation and apoptosis in nontransformed mouse epidermal tissues. The induction of both Caspase-3 and apoptosis by TPA were four-fold inhibited in the skin of the Tg(ped/pea-15) compared to the nontransgenic mice, accompanied by a similarly sized reduction in TPA-induced JNK and p38 stimulation and by constitutive induction of cytoplasmic ERK activity in the transgenics. ped/pea-15 expression was stably increased in cell lines from DMBA/TPA-induced skin papillomas and carcinomas, paralleled by protection from TPA apoptosis. In the A5 spindle carcinoma cell line, antisense inhibition of ped/pea-15 expression simultaneously rescued sensitivity to TPA-induced Caspase-3 function and apoptosis. The antisense also reduced A5 cell ability to grow in semisolid media by 65% (P<0.001) and increased by three-fold tumor latency time (P<0.01). Thus, the expression levels of ped/pea-15 control Caspase-3 function and epidermal cell apoptosis in vivo and determine susceptibility to skin tumor development.
Formisano
Pietro
P
Dipartimento di Biologia e Patologia Cellulare e Molecolare, Università di Napoli Federico II, Istituto di Endocrinologia ed Oncologia Sperimentale del CNR, Via Sergio Pansini, 5, Naples 80131, Italy.
Perruolo
Giuseppe
G
Libertini
Silvana
S
Santopietro
Stefania
S
Troncone
Giancarlo
G
Raciti
Gregory Alexander
GA
Oriente
Francesco
F
Portella
Giuseppe
G
Miele
Claudia
C
Beguinot
Francesco
F
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000633:toxicity; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D015153:Blotting, Western; D002273:Carcinogens / Q000633:toxicity; D053148:Caspase 3; D020169:Caspases / Q000378:metabolism; D002471:Cell Transformation, Neoplastic / Q000187:drug effects / Q000235:genetics; D002478:Cells, Cultured; D003043:Cocarcinogenesis; D016373:DNA, Antisense / Q000494:pharmacology; D004789:Enzyme Activation; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D015603:Keratinocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008819:Mice, Nude; D008822:Mice, Transgenic; D010212:Papilloma / Q000139:chemically induced / Q000235:genetics / Q000473:pathology; D010750:Phosphoproteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000502:physiology*; D012509:Sarcoma / Q000139:chemically induced / Q000235:genetics / Q000473:pathology; D012878:Skin Neoplasms / Q000139:chemically induced / Q000235:genetics / Q000473:pathology; D013755:Tetradecanoylphorbol Acetate / Q000633:toxicity; D014162:Transfection
D051017:Apoptosis Regulatory Proteins; D002273:Carcinogens; D016373:DNA, Antisense; D047908:Intracellular Signaling Peptides and Proteins; C092039:PEA15 protein, human; D010750:Phosphoproteins; D015127:9,10-Dimethyl-1,2-benzanthracene; C505407:CASP3 protein, human; C505409:Casp3 protein, mouse; D053148:Caspase 3; D020169:Caspases; D013755:Tetradecanoylphorbol Acetate