MOLECULAR ANALYSIS OF CELLULAR LOCI DISRUPTED BY PAPILLOMAVIRUS-16 INTEGRATION IN CERVICAL-CANCER - FREQUENT VIRAL INTEGRATION IN TOPOLOGICALLY DESTABILIZED AND TRANSCRIPTIONALLY ACTIVE CHROMOSOMAL REGIONS

To discern the structural features of cellular loci that are disrupted by type 16 human papillomavirus (HPV-16) integration in cervical canc er, a polymerase chain reaction (PCR)-based strategy was employed for direct amplification and sequence analysis of four such cellular loci in cancer biopsy samples. One of the HPV-16-disrupted loci was found t o be the microtubule-associated protein (MAP-2) gene and the other thr ee loci were uncharacterized and were designated PID-1 to -3 (for papi llomavirus integration-disrupted). The junctional sequences of the vir al integration sites in the four loci analyzed are bracketed by long t racts of homogeneous purine or pyrimidine or alternating purine-pyrimi dine which are known to destabilize the B-form conformation of the DNA structure. Using a panel of human/hamster hybrid cell DNAs and PCR an alysis, the four loci were assigned to chromosomes 2 (MAP-2), 9 (PID-1 ), 1 (PID-2) and 8 (PID-3), respectively. These chromosomes carry nume rous other previously determined viral integration and chromosomal fra gile sites and the myc oncogenes. The PID-1 locus was further found in Southern analysis to be rearranged and amplified in another cervical cancer biopsy and a cervical carcinoma cell line (CaSki). On Northern analysis, the PID-1 and -3 probes detected a 3.0- and a 3.6-kb transcr ipt, respectively, in normal cervical cells and in cervical cancer cel l lines. The findings suggest that HPV-16 genome integrates frequently into topologically destabilized and transcriptionally active chromoso mal sites. It remains to be elucidated whether the MAP-2 and the PID l oci contribute to the pathogenesis of cervical cancer. (C) 1996 Wiley- Liss, Inc.