TY - JOUR
T1 - 2-5A antisense directed against telomerase RNA produces apoptosis in ovarian cancer cells
AU - Kushner, David M.
AU - Paranjape, Jayashree M.
AU - Bandyopadhyay, Bhaswati
AU - Cramer, Hagen
AU - Leaman, Douglas W.
AU - Kennedy, Alexander W.
AU - Silverman, Robert H.
AU - Cowell, John K.
N1 - Funding Information:
1 Supported by United States Public Health Service Grant 1 PO1 CA 62220 awarded by the Department of Health and Human Services, National Cancer Institute (to R.H.S.).
PY - 2000/2
Y1 - 2000/2
N2 - Objective. RNase L is converted to an active form upon binding short 2',5'-oligoadenylates (2-5A). To direct RNase L to an RNA target, 2-5A is attached to an antisense oligonucleotide (2-5A antisense). This chimera can be directed against telomerase-an RNA-protein complex that elongates telomeric DNA and is involved in cellular immortalization. Our objective is to investigate the effect of 2-5A antisense by targeting telomerase RNA (hTR) in the ovarian cancer cell line, HEY-1B. Methods. Baseline RNase L levels and telomerase activities were measured in both HEY-1B and normal ovarian epithelial cells (NOE). Cells were treated daily with chimeric oligonucleotides (ODN) directed against four different hTR sites, or control ODNs including nonchimeric antisense, 2-5A fused to a mismatched sequence, or inactive 2-5A fused to antisense. At 48 h, apoptosis was evaluated using the TUNEL assay. After six daily ODN administrations, telomerase activity was redetermined, and at 7 days viability counts were obtained. Results. Both cell lines expressed similar levels of RNase L. Hey-1B displayed telomerase activity while NOE did not. After 7 days of transfection, 2-5A antisense ODNs caused profound cell death in the HEY-1B cells, but not in the NOE cells. This effect was seen regardless of hTR target site, and ODN controls showed no significant decrease in cell viability in either cell line. HEY1B cells treated with 2-5A antisense against hTR showed a decrease in telomerase activity and a profound induction of programmed cell death. Conclusions. The results suggest that 2-5A antisense directed against telomerase RNA results in apoptotic cell death in ovarian cancer cells, but not normal ovarian epithelial cells. The 2-5A antisense strategy may hold a considerable advantage over the conventional antisense approach in targeting cancer- causing genes.
AB - Objective. RNase L is converted to an active form upon binding short 2',5'-oligoadenylates (2-5A). To direct RNase L to an RNA target, 2-5A is attached to an antisense oligonucleotide (2-5A antisense). This chimera can be directed against telomerase-an RNA-protein complex that elongates telomeric DNA and is involved in cellular immortalization. Our objective is to investigate the effect of 2-5A antisense by targeting telomerase RNA (hTR) in the ovarian cancer cell line, HEY-1B. Methods. Baseline RNase L levels and telomerase activities were measured in both HEY-1B and normal ovarian epithelial cells (NOE). Cells were treated daily with chimeric oligonucleotides (ODN) directed against four different hTR sites, or control ODNs including nonchimeric antisense, 2-5A fused to a mismatched sequence, or inactive 2-5A fused to antisense. At 48 h, apoptosis was evaluated using the TUNEL assay. After six daily ODN administrations, telomerase activity was redetermined, and at 7 days viability counts were obtained. Results. Both cell lines expressed similar levels of RNase L. Hey-1B displayed telomerase activity while NOE did not. After 7 days of transfection, 2-5A antisense ODNs caused profound cell death in the HEY-1B cells, but not in the NOE cells. This effect was seen regardless of hTR target site, and ODN controls showed no significant decrease in cell viability in either cell line. HEY1B cells treated with 2-5A antisense against hTR showed a decrease in telomerase activity and a profound induction of programmed cell death. Conclusions. The results suggest that 2-5A antisense directed against telomerase RNA results in apoptotic cell death in ovarian cancer cells, but not normal ovarian epithelial cells. The 2-5A antisense strategy may hold a considerable advantage over the conventional antisense approach in targeting cancer- causing genes.
KW - 2-5A
KW - Antisense
KW - Ovarian cancer
KW - Telomerase
UR - http://www.scopus.com/inward/record.url?scp=0033980773&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0033980773&partnerID=8YFLogxK
U2 - 10.1006/gyno.1999.5668
DO - 10.1006/gyno.1999.5668
M3 - Article
C2 - 10637068
AN - SCOPUS:0033980773
SN - 0090-8258
VL - 76
SP - 183
EP - 192
JO - Gynecologic Oncology
JF - Gynecologic Oncology
IS - 2
ER -