Antisense oligonucleotide targeting at the initiator of hTERT arrests growth of hepatoma cells.

Abstract

To evaluate the inhibitory effect of antisense phosphorothioate oligonucleotide (asON) complementary to the initiator of human telomerase catalytic subunit (hTERT) on the growth of hepatoma cells. The as-hTERT was synthesized by using a DNA synthesizer. HepG2.2.15 cells were treated with as-hTERT at the concentration of 10 micromol/L. After 72 h, these cells were obtained for detecting growth inhibition, telomerase activity using the methods of MTT, TRAP-PCR-ELISA, respectively. BALB/c(nu/nu) mice were injected HepG2.2.15 cells and a human-nude mice model was obtained. There were three groups for anti-tumor activity study. Once tumors were established, these animals in the first group were administered as-hTERT and saline. Apoptosis of tumor cells was detected by FCM. In the 2nd group, the animals were injected HepG2.2.15 cells together with as-hTERT. In the third group, the animals were given as-hTERT 24 hours postinjection of HepG2.2.15 cells. The anti-HBV effects were assayed with ELISA in vitro and in vivo. Growth inhibition was observed in cells treated with as-hTERT in vitro. A significant different in the value of A570-A630 was found between cells treated with as-hTERT and control (P<0.01) by MTT method. The telomerase activity of tumor cells treated with as-hTERT was reduced, the value of A450 nm was 0.42 compared to control (1.49) with TRAP-PCR-ELISA. The peak of apoptosis in tumor cells given as-hTERT was 21.12%, but not seen in saline-treated control. A prolonged period of carcinogenesis was observed in the second and third group animals. There was inhibitory effect on the expression of HBsAg and HBeAg in vivo and in vitro. As-hTERT has an anti-tumor activity, which may be useful for gene therapy of tumors.