Effect of antisense human telomerase RNA on malignant phenotypes of gastric carcinoma.
OBJECTIVE
The study was designed to explore the effects of antisense human telomerase RNA (ahTR) on the malignant phenotype of gastric carcinoma cell line SGC-7901, and its potential role in gene therapy for tumors.


METHODS
An ahTR eukaryotic expression vector, including the sequence of template region of telomere repeats, was constructed by recombinant technology of molecules and then transfected into gastric carcinoma cell line SGC-7901 by liposome DOTAP. Subsequently, the expression of hTR RNA and ahTR RNA by reverse transcription-polymerase chain reaction, telomerase activity by telomeric repeat amplification protocol-ELISA (TRAP-ELISA), telomere length by Southern blotting, cell morphology under light microscope, cellular proliferation capacity by 3-(4,5-dimethyl-2 thiazoyl)-2,5-diphenyl-2H-tetrazolium bromide assay, cell-cycle distribution by flow cytometry, efficiency of clone formation in soft agar, and tumorigenecity in nude mice were examined and evaluated in ahTR-transfected cells, control plasmid pCI-neo transfected cells and their parental cells.


RESULTS
An ahTR eukaryotic expression vector was constructed and successfully transfected into SGC-7901 cells. The telomerase activity in ahTR-transfected SGC-7901 cells decreased from 100% to approximately 25%, and telomere length in the cells shortened to 3.35 from 4.08 Kb at 60 population doublings. Compared with the parental cells and pCI-neo transfected cells, ahTR-transfected cells displayed some morphological changes, such as decreased atypia, and recovery of contact inhibition and density inhibition under light microscope. Furthermore, ahTR-transfected cells displayed decreased invasive capacity in Borden's chamber invasive model, increased G0/G1 phase rate and apoptotic rate. Surprisingly, ahTR-transfected SGC-7901 cells lost their capacity for clone formation in soft agar and tumorigencity in nude mice.


CONCLUSIONS
Antisense-hTR transfection can inhibit the growth of SGC-7901 cells and partially reverse the malignant phenotypes. This study provides an exciting approach for cancer therapy by inhibiting telomerase activity using an antisense gene.
Yang
Shi-Ming
SM
Department of Gastroenterology, South-West Hospital, Third Military Medical University, Chongquing, China. shimingyang@yahoo.com
Fang
Dian-Chun
DC
Yang
Jin-Liang
JL
Liang
Guang-Ping
GP
Lu
Rong
R
Luo
Yuan-Hui
YH
Liu
Wei-Wen
WW
D000818:Animals; D017209:Apoptosis; D015139:Blotting, Southern; D002453:Cell Cycle / Q000235:genetics; D004797:Enzyme-Linked Immunosorbent Assay; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D010641:Phenotype; D016372:RNA, Antisense / Q000235:genetics* / Q000494:pharmacology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000201:enzymology* / Q000235:genetics; D019098:Telomerase / Q000235:genetics* / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured
D016372:RNA, Antisense; D019098:Telomerase