Anti-tumor effect of securinine and its resistance to toxicity of cyclophosphamide

AIM: To study the anti-tumor effect of SEC and its resistance to the toxicity of CTX. METHODS: Transplanted mouse tumor Sarcoma 180, model of bone marrow suppression caused by CTX (100 mg · kg^-1 · d^-1, ip) and MTT assay were used. RESULTS: The inhibition rates of SEC(2.5,5,10 mg · kg^-1 · d^-1 x 7, ip) against Sarcoma-180 were 5%~11%, 18%~38% and 32%~39% respectively. In combination with low dose of CTX (20 mg · kg^-1 · d^-1 · 2, ip), the effect was much more pronounced than that of independent administration, giving inhibition rates of 54%~87%. Moreover, the inhibitory effect of CTX (100 mg · kg^-1 · d^-1 · 1, ip) on DNA content in bone marrow and WBC was reduced by SEC, but there was no dose-dependent effect. The proliferation of three human tumor cell lines in vitro was inhibited after incubation with different concentrations of SEC for 24 h. The values of IC₅₀ were 26.8 mg · L^-1 (K 562), 98.2 mg · L^-1 (SHG-44) and 68.4 mg · L^-1 (HOS-8603) respectively. CONCLUSION: SEC has a certain anti-tumor effect and can reduce the toxicity of CTX.