Inhibition of Telomerase Activity by Cucurbitacin I in Colon Cancer Cell Line, LS174T

Abstract

Telomerase activity is dependent on the expression level of human telomerase reverse transcriptase (hTERT) in cancer cells. hTERT messenger ribonucleic acid (mRNA) is expressed in more than 85% of cancer cells, but not in normal human somatic cells. Therefore, the proliferation of human cancer cells can be arrested by telomerase inhibition. We aimed to investigate the effect of cucurbitacin I on the inhibition of hTERT mRNA expression in LS174T colorectal carcinoma cells. After treating the LS174T cells with various concentrations (2.5–125 ng/mL) of cucurbitacin I for 24 h, total RNA was extracted and cDNA was synthesized. Real-time PCR was used for quantitative assessment of hTERT mRNA gene expression versus control group. The level of hTERT mRNA was calculated via normalized to β-actin mRNA level which uniformly expressed housekeeping gene, within each sample. The results of our investigation suggested that cucurbitacin I significantly inhibited telomerase activity and showed a considerable decrease in mRNA expression of hTERT in the treated cells in comparison with the control cells in a concentration-dependent manner. Preliminary study shows that cucurbitacin I is effective for the inhibition of telomerase activity in colorectal cancer.

Keywords

• cucurbitacin I
• telomerase activity
• human telomerase reverse transcriptase messenger ribonucleic acid
• LS174T cell line