Ambiguine I Isolated from Fischerella ambigua Induces Apoptosis in Cancer Cells

Ambiguine I was previously isolated from Fischerella ambigua, and it was identified as a NF-κB inhibitor (IC₅₀= 30 nM). To further investigate the mechanism action through which ambiguine I exerts its biological effects on cancer cells, fluorescence activated cell sorting analysis was performed on treated HeLa cervical cancer cells. The DNA content was measured in both treated and untreated cells and an increased population of cells was detected in sub G₁-phase in the cells treated with ambiguine I. The preliminary results showed that 72% of treated cell were in sub G₁-phase, compared to 37% of the untreated cells. This effect was associated with G₁-phase block in the cell cycle and induction of apoptosis in treated cells. The biological and cellular effects on HeLa cervical cancer cells of ambiguine I are being further examined. The levels of protein expression of mediators of the NF-κB pathway are also being studied. The kinases IKK-α and IKK-β have been analyzed by Western blot analysis at increasing concentrations of ambiguine I. The NF-κB expression of p50 and p65 units have also been examined in treated cells and compared with the positive control, rocaglamide.