Telomere maintenance in telomerase‐positive human ovarian SKOV‐3 cells cannot be retarded by complete inhibition of telomerase

FEBS Letters

Johnston, Jeffrey¹  Lu, Jie¹  Mo, Yiqun¹  Gan, Yuebo¹  Wientjes, M.Guillaume¹  Au, Jessie L.-S¹ 

[1] College of Pharmacy, The Ohio State University, 500 West 12th Avenue, Columbus, OH 43210, USA

关键词: Telomerase;    Telomere;    Ovarian cancer;    Alternative lengthening of telomeres;    ALT;    alternative lengthening of telomeres;    AZT;    3′-azido-deoxythymidine;    FISH;    fluorescence in situ hybridization;    hTR;    human telomerase RNA component;    IPTG;    isopropyl-β-D-thiogalactopyranoside;    NHEJ;    non-homologous end joining;    PML;    promyelocytic leukemia;    TERT;    telomerase reverse transcriptase;    TRAP;    telomeric repeat amplification protocol;   

DOI  :  10.1016/S0014-5793(02)03141-1

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

The two known mechanisms for telomere maintenance in eukaryocytes are telomerase in telomerase-positive cells and alternative lengthening of telomeres (ALT) in telomerase-negative cells. We report here that telomere maintenance in the telomerase-positive human ovarian SKOV-3 cells was not affected by inhibition of telomerase. For comparison, the effect of telomerase inhibitors on telomere maintenance in another telomerase-positive cell line (i.e. human pharynx FaDu cells) and the telomerase-negative human osteosarcoma Saos-2 cells was examined. Telomerase activity was measured using a modified telomeric repeat amplification protocol and telomere length was measured using a solution hybridization-based method and fluorescence in situ hybridization. A reverse transcriptase inhibitor (3′-azido-deoxythymidine or AZT) and an antisense against a component of human telomerase RNA (antisense hTR) were used to inhibit telomerase. FaDu and SKOV-3 cells showed comparable baseline telomerase activity. Telomerase activity in both cells was inhibited about equally by AZT (maximal inhibition of ∼80%) and by expression of antisense hTR (complete inhibition in SKOV-3 cells and maximal inhibition of ∼80% in FaDu cells). However, treatment with telomerase inhibitors resulted in ∼50% telomere shortening in FaDu cells but had no effect on SKOV-3 nor Saos-2 cells. SKOV-3 cells did not show the characteristic features of ALT (i.e. heterogeneous telomere length and promyelocytic leukemia bodies), whereas these ALT features were observed in Saos-2 cells. Collectively, these results suggest the existence of a telomerase-independent mechanism of telomere maintenance in the telomerase-positive SKOV-3 cells.

【 授权许可】

Unknown