Effect Of Inhibited Telomerase Expression On Human Laryngeal Carcinoma Line Of Hep-2

Telomere is a simple repeating structure containing TTAGGG in the terminal of eukaryocyte chromosome. It can prevent chromosome degradation,terminal-terminal fusion, recombination and chromosome elimination to make chromosome stable. In the normal, because of self-defect during chromosome reproduction,telomere will loss 50-150 bp per cell division. As number of times of cell division increases, telomere DNA shortens gradually and cells come into crisis finally.Those events will lead to cell death. Telomerase is a complex of RNA and protein and a reverse transcriptase depending on RNA specially. It can de novo synthesis telomere DNA of chromosome terminal by using self RNA as template in order to make up telomere DNA loss during cell division, maintain telomere length and keep chromosome mobile equilibrium. Since paid Kim set up high sensitive method detecting telomerase based on PCR in 1994, telomerase has been paied widespread attention. Researchers discovered that there was close relationship between telomerase and cell proliferation,difFerentiation,eternal alive, which has become hot spot of tumour and apolexis studies.Incidence rate of carcinoma of larynx is the second among tumours in otorhinolaryngology .Mao li et al studied the telomerase expression of 16 head4Hep-2and neck carcinoma cell lines (including 7 carcinoma of larynx cell lines);29 head and neck carcinoma tissue samples and 17 normal side of carcinoma tissue samples. They found that telomerase expression! is positive (100%) in all 16 head and neck carcinoma cell lines and in 26 of 29 head and neck carcinoma tissue samples telomerase expression is positive (90%) ,but telomerase expression is negative (0%) in 17 normal side of carcinoma tissue samples.Hohaus detected telomerase activity of 36 laryngeal carcinoma tissue samples and 21 around carcinoma mucosae samples The result showed that telomerase expression! is positive in 32 of 36(88.9%) carcinoma of larynx tissue samples and 16 of 21(76.2%) around of carcinoma mucosae samples, and intensity of telomerase expression has correlation(P<0.05) with tumours volume and DNA content The larger of rumours volume and the more of DNA heteroploid content.the higher intensity of telomerase expression.To find the relationship between telemorase and carcinoma of larynx, we studied the effect of telomerase on cancer cell growth by detecting rtRNA telomerase expression .We transfected pBBS212-hTR(telomerase antisense RNA eukaryon expression vector) into human carcinoma of larynx Hep-2 cell lines, and assayed main telomerase activity by telomere repeat amplification,and detected cell cycle with MTT and FCM and observed cell growth with electron microscope The result showed that Hep-2 telomerase activity is high before transfection,and OD value is 3.102.But after transfection telemerase active declines, and OD value is 0.327 only,which indicated that telemerase antisense RNA can seal off or inhibit telomerase antisense RNA activity of Hep-2 .Cell growth dynamics showed that telomerase antisense RNA cound inhibit cell proliferation and extend doubling time .Result of electron microscope showed that there are edge collection phenomenon of chromatin or shaped apoptsis corpuscles in part Hep-2/pBBS212-hTR, whereas the control cells have no changes above . The results indicate the telomerase antisense RNA inhibit telomerase activity as well as tumour cell proliferation and lead Hep-2 sequence apoptosis. At the sameHep-2time anti-telomerase can escape side-effect of telomerase activity lack of on normal cells. In addition , because telomerase activity of primitive stem cell is lower than that of their filial generation cell, cure can lower inhibition to stem cell that directly at telomerase. To have spectral specificity, lower side defect merits that using inhibition telomerase activity .We think that anti-polynucleotide technique to telomerase can bring hope to cure carcinoma of larynx.