Bioactive compounds from the medicinal plant, Eurycoma longifolia Jack have been shown to promote anti-proliferative effects on various
cancer cell lines. Here we examined the effects of purified
eurycomanone, a
quassinoid found in Eurycoma longifolia Jack extract, on the expression of selected genes of the A549
lung cancer cells.
Eurycomanone inhibited A549
lung cancer cell proliferation in a dose-dependent manner at concentrations ranging from 5 to 20 μg/ml. The concentration that inhibited 50% of cell growth (GI(50)) was 5.1 μg/ml. The anti-proliferative effects were not fully reversible following the removal of
eurycomanone, in which 30% of cell inhibition still remained (p<0.0001, T-test). At 8 μg/ml (GI(70)),
eurycomanone suppressed anchorage-independent growth of A549 cells by >25% (p<0.05, T-test, n=8) as determined using soft
agar colony formation assay.
Cisplatin, a
chemotherapy drug used for the treatment of
non small cell lung cancer on the other hand, inhibited A549 cells proliferation at concentrations ranging from 0.2 μg/ml to 15 μg/ml with a GI(50) of 0.58 μg/ml. The treatment with
eurycomanone reduced the abundance expression of the
lung cancer markers,
heterogeneous nuclear ribonucleoprotein (
hnRNP) A2/B1,
p53 tumor suppressor protein and other
cancer-associated genes including
prohibitin (PHB),
annexin 1 (ANX1) and endoplasmic reticulum
protein 28 (ERp28) but not the house keeping genes. The
mRNA expressions of all genes with the exception of PHB were significantly downregulated, 72 h
after treatment (p<0.05, T-test, n=9). These findings suggest that
eurycomanone at viable therapeutic concentrations of 5-20 μg/ml exhibited significant anti-proliferative and anti-clonogenic cell growth effects on A549
lung cancer cells. The treatment also resulted in suppression of the
lung cancer cell
tumor markers and several known
cancer cell growth-associated genes.