In Vitro Modulation of Telomerase Activity, Telomere Length and Cell Cycle in MKN45 Cells by Verbascoside

Abstract

Screening of natural products with anti-tumor activity as telomerase inhibitor is a new subject in the field of tumor therapy. Using telomerase PCR ELISA, telomere DNA hybridization and flow cytometry analysis, the effects of verbascoside, a phenylpropanoid glucoside extracted from Pedicularis striata Pall, on telomerase activity, telomere length and cell cycle of human gastric carcinoma cells MKN45 was examined in vitro. After being treated with a 50 % inhibition concentration of verbascoside (17.8 microg/ml), telomerase activity in the cells was significantly inhibited but not in the cellular supernatant, the average telomere length became remarkably short, and the sub-G0 /G1 peak and G2/M arrest were also displayed when compared to the control cells. These results suggest that verbascoside mediated-cell differentiation and apoptosis may be affected by telomere-telomerase-cell cycle dependent modulation. Thus, the antitumor mechanism of verbascoside is demonstrated once more by its inhibiting effect on telomerase activity in tumor cells, and the telomerase assay may provide a valuable screening method for antitumor activity of natural products.

Natural Antioxidant Pedicularioside G Inhibits Angiogenesis and Tumourigenesis in vitro and in vivo

“…Pedicularioside G has anti-angiogenic, antitumour growth, antimetastatic and antitumoural effects. Our previous studies have shown that another phenylpropanoid glycoside, verbascoside (acteoside) extracted from Pedicularis species could reverse malignant phenotypic characteristics, induce tumour cell re-differentiation [27], inhibit telomerase activity and shorten telomere length of human gastric adenocarcinoma cells [28]. The present study further demonstrated that pedicularioside G remarkably decreased the angiogenesis and tumourigenesis.…”

The Retrovirus-mediated Antisense Human Telomerase RNA (hTR) Gene Limits the Growth of Hepatocellular Carcinoma Growth in Cell Culture and Animals

“…It has been confirmed that the highest rate of telomerase activity is at S phase, whereas the lowest is at the G2/M phase [23]. Thus, our data indicate that the G2/M phase blockage is largely responsible for the antisense gene-mediated down-regulation of telomerase activity, which is in agreement with results from previous investigations [24][25][26].…”

Anti-inflammatory and anti-ulcerogenic properties of Stachytarpheta cayennensis (L.C. Rich) Vahl

“…In fact, the chemical characterization by HPLC/UV of Stachytarpheta cayennensis extracts revealed higher amounts of iridoid than arylpropanoid in the ethanolic extract SC01, whereas in the extract SC02, arylpropanoid was predominant over iridoid. The arylpropanoid verbascoside (also called acteoside) is found in several species in the Verbenaceae family (Cometa et al, 1993), and has been shown to present a wide range of biological activities (Akbay et al, 2002;Sheng et al, 2002;Zhang et al, 2002). Indeed, Schapoval et al (1998) demonstrated an important anti-inflammatory activity of verbascoside isolated from Stachytarpheta cayennensis.…”