Résumé
Background: Telomerase is a ribonucleoproteins enzyme responsible for the maintenance of telomere length. Human telomerase reverse transcriptase [hTERT] is a major component of the catalytic subunit of telomerase enzymes and is expressed in cells that have telomerase activity but is not expressed in normal somatic cells. Based on the specific expression of hTERT in most cancer cells, it can be considered as a factor in the distinction between cancer cells and normal cells. It seems that inhibiting the expression of hTERT has been presented as a therapeutic approach in inhibiting the activity of telomerase. One of the special tools for inhibiting genes is the use of small interfering RNA [siRNAs]. The purpose of this study was to investigate the effect of hTERT gene on the cell viability and cell cycle in gastric cancer cells.
Materials and methods: In this study, human cancer cells, adenocarcinoma gastric cell line [AGS] were cultured in RPMI 1640 medium [Roswell Park Memorial Institute] containing 10 Percent FBS [Fetal Bovine Serum] and 1 Percent penicillin/streptomycin antibiotics. The suppression of the hTERT gene was accomplished by FlexiTube siRNA. The repression effect of hTERT gene was investigated on cell viability by MTT assay [3-[4, 5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide] with ELISA [Enzyme Linked Immunosorbent Assay] reader at 570 nm, and cell cycle performed by flow cytometry and DAPI [4', 6-diamidino-2-phenylindole] staining.
Results: The effect of hTERT siRNA on the cell viability by MTT assay showed time dependent cell viability of AGS cell line upon treatment and increasing the exposure time to 48 hours for that concentration decreased AGS cell [p = 0.02]. Analysis of flow cytometry also showed increased number of cells in G1 phase and decreased the number of cells in S phase, and induced apoptosis via decreasing the level of hTERT expression.
Conclusion: The significant downregulation in hTERT mRNA after 48 hours of hTERT siRNA treatment inhibited the cell viability of AGS cells and cell cycle arrest
Résumé
Gastric cancer as the fourth most frequent malignancy worldwide was known to have the highest rate among cancer-related disorders in Ardabil province. The product of TP53 gene regulated the cell cycle process and acts as a tumor suppressor factor. The polymorphism P53 Arg72Pro [rs1042522] has been reported to be associated with many type of cancers. The purpose of the present study was investigating about susceptibility of gaining gastric cancer in which probably conferred by the polymorphism P53 Arg72Pro in Ardabil province. Using PCR-RFLP, the polymorphism was assayed among 87 patients affected with gastric cancer and 92 healthy controls selected. The statistical significance was analyzed by logistic regression test. The mean of age for cases and controls were 64.2 and 61.9 years respectively. The frequency of genotypes for cases has been detected as 16.3% for Pro/Pro, 41.9% for Arg/Pro, and 41.9% for Arg/Arg and for controls were 18.5% Pro/Pro, 40.2% Arg/Pro, and 41.3% Arg/Arg respectively. There was not any significant association between this polymorphism and affecting to gastric cancer. Finding shows relationship between susceptibility of gaining gastric cancer in our province and the polymorphism rsl 042522 could be due to genetic and population relationship between Ardabil population and Caucasians, and the selective advantage of the Arg allele in cold climates, as well. On the other hand, considering to the previous studies on the etiology of gastric cancer in Ardabil province shows, environmental factors such as nitrate have more important role bin conferring susceptibility to gain gastric cancer and some genetic changes and affecting to gastric cancer in this study indicates that the role of lifestyle improvement might reduce the huge rate of affected patients in our province