Influence of 17beta-estradiol on the expression of oncogenes E6 and E7 of human papillomavirus type 18 in HeLa cell line
The relationship between HPV (Human Papillomavirus) and cervical carcinoma is very strong, causal, constant, specific and universal. HPV infection precedes the occurrence of preinvasive carcinoma and the evidence for biological probability of such relationship does not leave any doubt. Out of high-risk HPV types, the most often occurring in cervical infections types 16 and 18 were placed in the first group of human carcinogens. However, HPV infection is not the only factor of malignant neoplasm development. Neuroplastic transformation of cervical epithelium requires the presence of cofactors. In recent years, higher role is ascribed to the influences of steroid hormones, including estradiol and progesterone. In normal and neoplastic cells of uterine cervix, the occurrence of receptors for steroid hormones was described. In the regulatory region of oncogenic HPV hormone response elements were found. Receptors combined with steroid hormones functioning as transcription factors may influence the expression of viral oncogens E6 and E7 through stimulation of proliferation and transformation. The aim of this study was to analyse the influence of 17ß-estradiol on the amount of proteins E6 and E7 HPV 18 and to evaluate the transcript E6/E7 after incubation of HeLa line cells with 17ß-estradiol. The results revealed stimulating influence of the hormone on the expression of proteins and mRNA at concentrations of lx10-7M. At high concentrations of 1x10- 4M, estradiol was inhibiting transcription and expression of oncoproteins.