Effect of Ginkgo biloba extract EGb761 on apoptosis of K-ras mutational human colon cancer cells DLD1 and its mechanism

Objective To explore the effect of Ginkgo biloba extract (EGb761) on apoptosis of K-ras mutational human colon cancer cells DLD1 (DLD1/G13D) and its mechanism. Methods Human colon cancer cell lines DLD1/G13D and DLD1 with K-ras wild type (DLD1/WT) were cultured in vitro, the cell proliferation and apoptosis after 24 h of EGb761 were measured. Proteins involved in related signal pathway were detected by Western blot or ELISA. Results EGb761 reduced cell proliferation and induced cell apoptosis in a concentration-dependent manner in DLD1/WT and DLD1/G13D cells. EGb761 downregulated the expression of RIP1, impaired the phosphorylation of IκB and decreased the level of NF-κB in DLD1/WT and DLD1/G13D cells [DLD1/G13D: (24 ± 4)%, DLD1/WT: (29 ± 9)% (P < 0.05). Conclusion EGb761 restrains the proliferation and induces the apoptosis of DLD1/WT and DLD1/G13D cells. The mechanism may be related to the degradation of RIP-1 and inhibition of activation of NF-κB signaling pathway. Key words: Colonic neoplasms; Ginkgo biloba extract; Mutation; Apoptosis; NF-κB signaling pathway