Effects of acetylmelodorinol and plaunotol on cancer cell lines

Abstract

This study was aimed at determining effects of acetylmelodorinol and plaunotol on four human cancer cell lines (BT474, HepG2, KATOIII, and SW620) and two normal human cell lines (CH-liver and Hs27). Tested cells were cultured in the presence or absence of acetylmelodorinol and plaunotol at various concentrations (010 g/ml) for 12, 24, 48, and 72 h and the percentages of cell viability were evaluated by MTT assay. The results indicated that both acetylmelodorinol and plaunotol have significant antiproliferative effect at 48 h of incubation, compared to control untreated cells and cells treated for 12-24 h (p<0.01). Acetylmelodorinol showed a dose and time-dependent inhibition of cell proliferation at 48 h of incubation with IC50 of 1.43+-0.39 g/ml against BT474, 4.32+-0.89 g/ml against HepG2, 3.10+-0.48 g/ml against KATOIII, 1.39+-0.08 g/ml against SW620, and 2.80+-0.35 g/ml against CH-liver. Acetylmelodorinol did not show antiproliferative effect against Hs27 cell. Plaunotol showed a dose and time-dependent inhibition of cell proliferation at 48 h of incubation with IC50 of 7.07+-1.44 g/ml against BT474, 6.11+-1.15 g/ml against HepG2, 10.36+-2.19 g/ml against KATOIII, and 6.90+-0.68 g/ml against SW620. However, plaunotol did not show antiproliferative effect against normal cells. In addition, antiproliferative effect of acetylmelodorinol was associated with apoptosis in SW620 cells as determined by morphological changes and oligonucleosomal DNA fragmentation. The confirmation of apoptosis assessed by Annexin-V-FITC staining showed that when SW620 cells were treated with 5 g/ml of acetylmelodorinol, the number of apoptotic cells increased from 29.02+-4.99 % to 56.38+-3.73% at 12 and 24 h, respectively. Necrotic cells as determined by PI staining, was negligible during this incubation time. To investigate the molecular mechanism leading to apoptosis, we examined the expression of pro-apoptotic gene (p53), and anti-apoptotic gene (Bcl-2) by RT-PCR. Both genes were expressed in untreated SW620 cells. Acetylmelodorinol treatment did not change the level of expression of p53 gene, but decreased the level of expression of Bcl-2, at 4-10 h incubation times. Taken together, these results suggested that acetylmelodorinol had strong antiproliferative, and apoptosis inducing effects in SW620 cells. The downregulation of Bcl-2 may be the molecular mechanism underlying this effect. However, plaunotol showed moderate antiproliferative effect on human cancer cell lines but did not show any effect in normal cells and did not induce apoptosis.