Acetyl-keto-β-boswellic acid inhibits cellular proliferation through a p21-dependent pathway in colon cancer cells

1 Although there is increasing evidence showing that boswellic acid might be a potential anticancer agent, the mechanisms involved in its action are unclear. 2 In the present study, we showed that acetyl-keto-b-boswellic acid (AKBA) inhibited cellular growth in several colon cancer cell lines. Cell cycle analysis by flow cytometry showed that cells were arrested at the G1 phase after AKBA treatment. 3 Further analysis showed that cyclin D1 and E, CDK 2 and 4 and phosphorylated Rb were decreased in AKBA-treated cells while p21 expression was increased. 4 The growth inhibitory effect of AKBA was dependent on p21 but not p53. HCT-116 p53(-/-) cells were sensitized to the apoptotic effect of AKBA, suggesting that p21 may have protected cells against apoptosis by inducing a G1 arrest. 5 In conclusion, we have demonstrated that AKBA inhibited cellular growth in colon cancer cells. These findings may have implications to the use of boswellic acids as potential anticancer agents in colon cancer.