Epidermal abnormalities and increased malignancy of skin tumors in human epidermal keratin 8-expressing transgenic mice.
Keratins K8 and K18 are the major components of the intermediate filament cytoskeleton of simple epithelia. Increased levels of these keratins have been associated with invasive growth and progression to malignancy in different types of human and murine epithelial tumors (including skin tumors), and even in tumors from nonepithelial origin. However, it has not yet clarified whether K8/K18 expression in tumors is cause or consequence of malignancy. Given the increasing incidence of epidermal cancer in humans (40% of all tumors diagnosed), we generated a mouse model to examine the role of simple epithelium keratins in the establishment and progression of human skin cancer. Transgenic mice expressing human K8 in the epidermis showed severe epidermal and hair follicle dysplasia with concomitant alteration in epidermal differentiation markers. The severity of the skin phenotype of these transgenic mice increases with age, leading to areas of preneoplastic transformation. Skin carcinogenesis assays showed a dramatic increase in the progression of papillomas toward malignancy in transgenic animals. These results support the idea that K8 alters the epidermal cell differentiation, favors the neoplastic transformation of cells, and is ultimately responsible of the invasive behavior of transformed epidermal cells leading of conversion of benign to malignant tumors.
Casanova
M Llanos
ML
Epithelial Damage, Repair and Tissue Engineering, CIEMAT, Avenida Complutense 22, 28040 Madrid, Spain. llanos.casanova@ciemat.es
Bravo
Ana
A
Martínez-Palacio
Jesús
J
Fernández-Aceñero
M Jesús
MJ
Villanueva
Concepción
C
Larcher
Fernando
F
Conti
Claudio J
CJ
Jorcano
José L
JL
D000375:Aging / Q000473:pathology / Q000502:physiology; D000818:Animals; D000831:Animals, Newborn; D002454:Cell Differentiation; D002471:Cell Transformation, Neoplastic; D018450:Disease Progression; D004817:Epidermis / Q000002:abnormalities* / Q000378:metabolism / Q000473:pathology; D018859:Hair Follicle / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007633:Keratins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008822:Mice, Transgenic; D011230:Precancerous Conditions / Q000378:metabolism / Q000473:pathology; D012868:Skin Abnormalities / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D012878:Skin Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D019076:Transgenes / Q000235:genetics
D007633:Keratins