Cepharanthine potentiates the antitumor effect of methylglyoxal bis (cyclopentylamidinohydrazone) on human leukemia cells.

Antiproliferative effects of cepharanthine, a biscoclaurine alkaloid, in combination with methylglyoxal bis (cyclopentylamidinohydrazone) (MGBCP), an inhibitor for polyamine biosynthesis, were investigated. The antitumor activity of MGBCP on human leukemic cells was potentiated by cepharanthine. Cellular polyamine levels in the leukemic cells treated with both MGBCP and cepharanthine were much lower than those of the cells treated with MGBCP alone. On the contrary, the cellular MGBCP concentration was much higher in the cepharanthine-treated leukemic cells. Thus cepharanthine was considered to enhance the incorporation of MGBCP into the leukemic cells. The combination of MGBCP and cepharanthine resulted in a greater suppression of macromolecule synthesis in the cells that might have caused the greater suppression of tumor cell growth.