Synthesis and anti-metastatic effects of pregn-17(20)-en-3-amine derivatives

Novel pregn-17(20)-en-3-amine derivatives were synthesized and their anti-metastatic effects were evaluated in human breast cancer cells using chemotaxis assay. Compared with positive control LY294002, a PI3K inhibitor, derivatives 5a, 19a, 20a, 19g, 20f, 5c, 12e and 12f exhibited significant inhibitory effects against cancer cell migration induced by chemokine epidermal growth factor (EGF). Especially, the IC₅₀ for compound 20f was as low as 0.03 μM. Preliminary structure-activity relationship studies suggested that most 3β-substituted derivatives were more effective than those 3α-substituted derivatives, provided there was no substituted group at position C-16. Moreover, the α,β-unsaturated fragment in ring D might be critical for their anti-metastatic activities. Further investigations on compound 20f revealed inhibitory effects on cell adhesion, migration and invasion of MDA-MB-231 cells. The mechanisms for the anti-metastatic effect of 20f might be through the inhibition of the phosphorylations of PI3K, Akt, PKCζ, and integrin β1 in a dose-dependent manner. Taken together, the novel steroidal alkaloid derivative 20f could be further explored as an effective anti-metastatic agent for the treatment of human metastatic breast cancer.