Investigation of hTERT gene expression levels in two cell lines infected by high-risk human papilloma virus

Human papilloma virus (HPV) is one of the most important factors in cervical cancer. Viral sequences are integrated into the host cell genome. In mild cases the virus causes skin damages, in severe cases it leads to cancer. Like many other cancers, telomerase gene expression was increased in cervical cancer. This enzyme is a reverse transcriptase that contains two common subunits: i) catalytic protein called human telomerase reverse transcriptase (hTERT) and, ii) RNA sequence called hTR. hTERT expression is hardly found in any somatic tissues. Detection of high telomerase activity in human cells, lead to tumor genesis. So hTERT can be used as a diagnostic tool in cancer detection.
This experimental study was carried out from May 2013 to April 2014 in Nanobiotechnology Research Center, Baqiyatallah University of Medical Sciences in Tehran, Iran. Caski and Hela cancer cell lines were used which contain HPV16 and HPV18 respectively. Cell lines were cultured and total RNA was extracted. Following normalization agent glyceraldehyde-3-phosphate dehydrogenase (GADPH), hTERT expression level was determining by real-time PCR method. For each sample, the expression level of hTERT and GAPDH were quantified as copy numbers (per reaction) using the standard curve. Finally, hTERT levels in Hela and Caski cell lines were compared quantitatively by t-test using GraphPad statistic software version 5 (San Diego, CA, USA).
According to the charts real-time PCR, hTERT gene expression in Hela and Caski cancer cell lines is significantly different (t=0.0319).
All results confirm that hTERT expression levels in Hela and Caski cell lines are significantly different and the level of hTERT expression in the Caski cell line was slightly higher than that of Hela cell line. The significant difference between hTERT mRNA expression levels reported here could be used as a tumor marker for HPV16 and HPV18 in cervical cancer.