Cytogenetic analysis of eight human papillomavirus immortalized human keratinocyte cell lines

Cytogenetic analysis was performed on human papillomavirus (HPV)-immortalized cell lines. Lines were established by co-transfection of primary human keratinocyte cells with HPV type 16 or 18 DNA and pSV2neo. The resulting clonal lines contained integrated HPV DNA and exhibited extended life spans in culture but were non-tumorigenic in nude mice. Two HPV16-immortalized lines (FEPE1L8 and FEPE1L9) and 4 HPV18-immortalized lines (FEA, FEH18L, FEP18-5 and FEP18-11) were established. Two additional lines were derived by subsequent treatment of the FEA line with TPA and by further transfection with HSVII DNA. Cytogenetic analysis revealed that all lines were abnormal, containing a variety of numerical and structural aberrations. Six of the 8 lines were hyper-triploid and 2 were near-diploid. Examination of lines FEA, FEH18L and FEP18-11 at multiple passages in culture revealed that the lines were clonal and chromosomally stable over extended passage in culture. Structural rearrangements were most common in chromosomes 1 and 3 but also occurred in chromosomes 5, 7, 8, 12, 16 and 22. Marker chromosomes were present in all cell lines. A small metacentric marker, possibly an isochromosome for the short arm of chromosome 5, was consistently present in the FEA line and its derivatives (FEAB10 and FEAT) as well as the FEH18L line. A loss or reduction in copy number of chromosome 13 was seen in 5 of the 8 cell lines.