Telomerase Activity And The Expression Of Human Telomerase Reverse Transcriptase In Condyloma Acuminata Tissues

Condyloma Acuminatum (CA) is a kind of sexually transmitted disease with an increasing incidence in recent years. As a papillary-like proliferative lesion, it closely related to the infection of human papillary virus (HPV), especially the subtypes 6,11, 16 and 18. It was reported that the infection of HPV subtypes 16 and 18 might be related with the development of anal cancers and carcinomas of genitalia, such as cervix, vulvae and penis.In recent years, telomerase was one of the hotspots in the research area of oncology. It is thought that telomerase plays the primary role in maintaining length of telomeres which locate in the distal ends of human chromosomes. Telomeres protect the ends of chromosomes and keep chromosomes stable. According to massresearches, telomerase activity was activated in germ cells and most malignant tumors. Telomerase reactivation allows the possibility of cellular immortality and may thus be a major step in human carcinogenesis. As for its structure, telomerase is a specialized ribonucleoprotein polymerase containing three major components, including the RNA subunit - human telomerase RNA (hTR) serving as the RNA template for the telomeric repeats, the protein component - human telomerase associated protein I (hTEP I) and the catalytic subunit - human telomerase reverse transcriptase (hTERT). Of the components identified, hTERT appears to be the subunit responsible for the telomerase activity. Telomerase activity could be reconstituted by ectopic expression of hTERT. A lot of studies have shown that the close correlation of telomerase activity with the expression of hTERT gene. However, telomerase activity and the over-expression of hTERT gene could be detected in a cohort of normal tissues, benign and premalignant diseases. Even though, hTERT gene expression is much stronger in immortalized and malignant cells than in normal or premalignant cells.It has been reported that telomerase activity could be detected in some CA tissues, while the expression of hTERT in this disease has been never reported up to the present. Therefore, in this study, we simultaneously measured the telomerase activity and the expression of hTERT mRNA in CA lesions, in order to clarify the significance of hTERT in Condyloma Acuminatum pathogenesis.MATERIALS AND METHODSThirty-four lesions from 34 different CA patients and 14 normal skin tissues were collected via outpatient operations in the Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, during December 2002 to May 2003. All patients had typical lesion and were clinically diagnosed as Condyloma Acuminatum. Telomerase activity was detected by telomerase PCR ELISA method. Real-time fluorescent quantitative PCR was employed to measure the expression level of hTERT mRNA. HPV typing of CA tissues were determined by PCR method.RESULTSTelomerase Activity in Condyloma Acuminatum LesionsFifteen of 34 (15/34, 44.1%) CA lesions exhibited telomerase activity with the absorbance value (A_450nm - A_690nm) higher than 0.15, while the other 19 CA lesions showed telomerase negative. The mean absorbance value of telomerase positive and telomerase negative CA tissues were 0.326 ± 0.176 and 0.068 ± 0.049, respectively. As for the positive control, the 293 immortal cell lines, its absorbance value was 1.027 which was much higher than that in CA tissues. Of 14 normal skins, nine were telomerase negative, while the other five (5/14, 35.7%) were telomerase positive,which mean absorbance value of telomerase positive and negative were 0.166 ± 0.021 and 0.021 ± 0.021 respectively. Furthermore, all the telomerase positive samples exhibited a typical 6-bp ladder pattern on silver-stained 12% polyacrymide gels.Expression of hTERT mRNA in Condyloma Acuminatum LesionshTERT mRNA detection was simultaneously assayed in 24 CA cases which had sufficient tissues for both telomerase assay and RNA preparation. All 24 samples and 8 normal skins tested did not express hTERT above the detection limit, whereas the positive control - an immortal cell line did.HPV Typing in Condylom...