Effective Inhibition of Cancer Cell Growth by a Novel Tripartite T ransfection Complex Containing Ribbon Antisense Molecules to hTR

Abstract

Purpose: In the present study, ribbon antisense to the hTR RNA, a component of the telomerase complex, was employed to inhibit telomerase activity and cancer cell growth. Materials and Methods: Ribbon antisense molecules to the human hTR gene (hTR-RiAS) were constructed and complexed with a short modified peptide and cationic liposomes to improve the cellular uptake of the antisense molecules. The DPL complexes containing hTR-RiAS were transfected into target cancer cells. Various assays were performed to confirm the effects of the hTR-RiAS on the gene expression and cell proliferation. Results: When cancer cells were treated with hTR-RiAS, the cellular level of hTR mRNA was reduced by more than 95%, as shown by RT-PCR. Further, the telomerase activity was also affected by the antisense treatment. In contrast, both mismatched and scrambled oligonucleotides failed to reduce the levels of hTR mRNA and telomerase activity. When checked for cancer cell viability, hTR- RiAS inhibited cell growth by more than 70%, in a very rapid manner. The reduced cell viability was found to be due to apoptosis of cancer cells. Conclusion: These results show that hTR-RiAS is a powerful anticancer reagent, with the potential for broad efficacy to diverse malignant tumors.