TY - JOUR
T1 - Different HPV16 E6/E7 oncogene expression patterns in epithelia reconstructed from HPV16-immortalized human endocervical cells and genital keratinocytes
AU - Sun, Qi
AU - Tang, Shou Ching
AU - Pater, Mary M.
AU - Pater, Alan
N1 - Funding Information:
Excellent technical assistance by G Jin is acknowledged. We thank DG Haegert for clinical samples and assistance in the pathology, WW Franke for HaCaT cells, FX Bosch for plasmid 4/1EX.1 containing the human CK1 gene, MA Stanley, for W12 cells, NS Belaguli for pBSE7 plasmid used as probe for E6/E7 RNA, L Gissmann and H zur Hausen for pHPV16 DNA, T Michalak and G Paterno for assistance with micrography, E Evelly for histology and SV Atkins and J Petten for typing the manuscript. This investigation was supported in part by grants from the National Cancer Institute, with funds from the Canadian Cancer Society, and from the Medical Research Council of Canada.
PY - 1997
Y1 - 1997
N2 - Human papillomavirus type 16 (HPV16) E6/E7 oncogenes immortalize two types of human genital epithelial cells in vitro, endocervical cells and ectocervical or foreskin keratinocytes. Epithelia reconstructed in in vivo nude mouse implants or in vitro organotypic raft cultures from immortalized endocervical cells form higher grade dysplasia than those from keratinocytes. Here, we compared viral E6/E7 mRNA expression in immortalized cell lines of the three cell types using implants, rafts and in situ hybridization assays. Endocervical cells expressed E6/E7 throughout their reconstructed epithelia. In contrast, oncogenes were limited to basal cells for keratinocyte lower grade dysplasias. To study the role of the HPV16 promoter/enhancer in this repression in the upper layers of keratinocyte epithelia, new cell lines were established by immortalization with E6/E7 controlled by the SV40 promoter. The oncogenes were shown to be controlled from the SV40 elements after immortalization. Nevertheless, E6/E7 in the two cell types had the same cell-specific expression pattern as that controlled from the homologous HPV16 promoter. In addition, naturally occurring premalignant lesions having integrated HPV16 DNA expressed E6/E7 extensively in the high-grade dysplastic region of undifferentiated metaplasia. On the other hand, oncogene expression was restricted to lower layers in the lower grade dysplastic region of more mature differentiation. Our data suggest that keratinocytes have an inherent HPV16 promoter-nonspecific mechanism of repression. Apparently this mechanism, which can be acquired during maturation, is initially nonfunctional in in vitro and in vivo epithelia derived from metaplastic endocervical cells.
AB - Human papillomavirus type 16 (HPV16) E6/E7 oncogenes immortalize two types of human genital epithelial cells in vitro, endocervical cells and ectocervical or foreskin keratinocytes. Epithelia reconstructed in in vivo nude mouse implants or in vitro organotypic raft cultures from immortalized endocervical cells form higher grade dysplasia than those from keratinocytes. Here, we compared viral E6/E7 mRNA expression in immortalized cell lines of the three cell types using implants, rafts and in situ hybridization assays. Endocervical cells expressed E6/E7 throughout their reconstructed epithelia. In contrast, oncogenes were limited to basal cells for keratinocyte lower grade dysplasias. To study the role of the HPV16 promoter/enhancer in this repression in the upper layers of keratinocyte epithelia, new cell lines were established by immortalization with E6/E7 controlled by the SV40 promoter. The oncogenes were shown to be controlled from the SV40 elements after immortalization. Nevertheless, E6/E7 in the two cell types had the same cell-specific expression pattern as that controlled from the homologous HPV16 promoter. In addition, naturally occurring premalignant lesions having integrated HPV16 DNA expressed E6/E7 extensively in the high-grade dysplastic region of undifferentiated metaplasia. On the other hand, oncogene expression was restricted to lower layers in the lower grade dysplastic region of more mature differentiation. Our data suggest that keratinocytes have an inherent HPV16 promoter-nonspecific mechanism of repression. Apparently this mechanism, which can be acquired during maturation, is initially nonfunctional in in vitro and in vivo epithelia derived from metaplastic endocervical cells.
KW - E6/E7 oncogene expression
KW - Endocervical cells
KW - Human papillomavirus type 16
KW - Keratinocytes
KW - Metaplasia
KW - Stratified squamous epithelium
UR - http://www.scopus.com/inward/record.url?scp=0030815807&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0030815807&partnerID=8YFLogxK
U2 - 10.1038/sj.onc.1201425
DO - 10.1038/sj.onc.1201425
M3 - Article
C2 - 9395236
AN - SCOPUS:0030815807
SN - 0950-9232
VL - 15
SP - 2399
EP - 2408
JO - Oncogene
JF - Oncogene
IS - 20
ER -