TY - JOUR
T1 - Targeted disruption of the epidermal growth factor receptor inhibits development of papillomas and carcinomas from human papillomavirus-immortalized keratinocytes
AU - Woodworth, Craig D.
AU - Gaiotti, Darci
AU - Michael, Evan
AU - Hansen, Laura
AU - Nees, Matthias
PY - 2000/8/15
Y1 - 2000/8/15
N2 - The epidermal growth factor receptor (EGF-R) is frequently overexpressed in human papillomavirus (HPV)-associated dysplasias and carcinomas, implying that it is important for the progression of keratinocytes to malignancy. We used mice with a targeted disruption of the EGF-R gene to directly examine its role in cell immortalization and tumor development. Epidermal keratinocytes were cultured from EGF-R knockout, heterozygous, and wild-type mice, infected with retroviruses encoding HPV-16 E6 and E7 oncogenes, and grafted to nude mice. E6/E7 induced immortalization of EGF-R wild-type cells 5-fold more efficiently than null cells. Immortal EGF-R null cells grew more slowly, achieved a lower saturation density, and were more sensitive to apoptosis than the immortalized wild-type or heterozygous cells. Analyses using cDNA expression arrays showed that EGF-R null cells expressed increased levels of RNAs encoding p21waf and insulin-like growth factor-binding protein-2. EGF-R-positive immortal keratinocytes formed papillomas in 17% (15 of 90) of skin grafts, and seven grafts progressed to squamous carcinoma after 6-12 months. EGF-R null keratinocytes did not form papillomas, but 1 of 96 grafts progressed to a squamous carcinoma after 1 year. However, treatment with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate induced tumors in 18 and 35% of grafts containing EGF-R null or EGF-R-positive cells, respectively. Transduction with an activated v-Haras gene, which signals downstream of the EGF-R, induced rapidly growing carcinomas in all grafts regardless of EGF-R genotype. These results directly show that the EGF-R is important, but not essential, for immortalization by HPV and for progression of immortal cells to papillomas and carcinomas.
AB - The epidermal growth factor receptor (EGF-R) is frequently overexpressed in human papillomavirus (HPV)-associated dysplasias and carcinomas, implying that it is important for the progression of keratinocytes to malignancy. We used mice with a targeted disruption of the EGF-R gene to directly examine its role in cell immortalization and tumor development. Epidermal keratinocytes were cultured from EGF-R knockout, heterozygous, and wild-type mice, infected with retroviruses encoding HPV-16 E6 and E7 oncogenes, and grafted to nude mice. E6/E7 induced immortalization of EGF-R wild-type cells 5-fold more efficiently than null cells. Immortal EGF-R null cells grew more slowly, achieved a lower saturation density, and were more sensitive to apoptosis than the immortalized wild-type or heterozygous cells. Analyses using cDNA expression arrays showed that EGF-R null cells expressed increased levels of RNAs encoding p21waf and insulin-like growth factor-binding protein-2. EGF-R-positive immortal keratinocytes formed papillomas in 17% (15 of 90) of skin grafts, and seven grafts progressed to squamous carcinoma after 6-12 months. EGF-R null keratinocytes did not form papillomas, but 1 of 96 grafts progressed to a squamous carcinoma after 1 year. However, treatment with the tumor promoter 12-O-tetradecanoylphorbol-13-acetate induced tumors in 18 and 35% of grafts containing EGF-R null or EGF-R-positive cells, respectively. Transduction with an activated v-Haras gene, which signals downstream of the EGF-R, induced rapidly growing carcinomas in all grafts regardless of EGF-R genotype. These results directly show that the EGF-R is important, but not essential, for immortalization by HPV and for progression of immortal cells to papillomas and carcinomas.
UR - http://www.scopus.com/inward/record.url?scp=0034662650&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0034662650&partnerID=8YFLogxK
M3 - Article
C2 - 10969784
AN - SCOPUS:0034662650
VL - 60
SP - 4397
EP - 4402
JO - Cancer Research
JF - Cancer Research
SN - 0008-5472
IS - 16
ER -