Integration of human papillomavirus 18 DNA in esophageal carcinoma 109 cells.

aimTo detect human papillomavirus (HPV) DNA in esophageal carcinoma (EC) 109 cells and investigate the relationship between HPV and EC.

methodsGenomic DNA and total RNA from EC109 cells were isolated. HPV DNA was detected by polymerase chain reaction (PCR) with the general primer sets of My09/11 and GP5 +/6 + for the HPV L1 gene and type-specific primer sets for HPV18 E6 and HPV18 E6-E7. Reverse transcription (RT) of mRNA isolated from EC109 cells was performed to produce a cDNA. And then a PCR-based protocol for the amplification of papillomavirus oncogene transcripts was used to analyze HPV18 DNA and integrated transcripts of HPV18 in the chromosomes of EC109 cells. The final nested PCR products were cloned into a pMD-18T vector and sequenced to analyze the chromosomal location of HPV integration.

resultsHPV18 DNA was detected in EC109 cells by PCR using the general primer sets of My09/11 and GP5 +/6 + for HPV L1 and the type-specific primer sets for HPV18 E6 and E6-E7 to generate products of 450 bp, 150 bp, 335 bp and 944 bp, respectively. Approximately 600 bp of integrated HPV18-specific transcript was identified. The final nested PCR product of integrated HPV18 DNA was cloned into a pMD-18T vector and sequenced to analyze the chromosomal location of HPV integration. Sequence alignment showed that the HPV18 sequence from EC109 cells was identical to that of the encoded early protein E7-E1 of the standard HPV18 strain X05015, and another partial gene sequence was identical to a partial sequence of human chromosome 8.

conclusionIntegration of the HPV genome into the host cell chromosome suggests that persistent HPV infection is vital for malignant cell transformation and carcinogenesis.