Purification of Pierisin, an Inducer of Apoptosis in Human Gastric Carcinoma Cells, from Cabbage Butterfly, Pieris rapae

A substance strongly cytotoxic to human carcinoma cell line TMK‐1 has been found in pupae, larvae and adults of the cabbage butterfly, Pieris rapae, and named pierisin. Pierisin was purified from the pupae of P. rapae by ammonium sulfate precipitation followed by DEAE‐cellulose, Phenyl‐Sepharose and hydroxyapatite column chromatographies. The molecular weight of the purified pierisin, which was homogeneous on SDS‐polyacrylamide gel, was analyzed by mass spectrometry and found to be 98 kDa. Pierisin showed a strong cytotoxic effect, with an IC(50) of 0.75 ng/ml for human gastric carcinoma TMK‐1 cells. The dying cells exhibited characteristic morphological features of apoptosis, such as cell shrinkage, chromatin condensation and nuclear fragmentation. Oligonucleosomal DNA fragmentation was also observed in DNA isolated from pierisin‐treated cells. Moreover, similar characteristic changes showing apoptotic cell death were observed in TMK‐1 cells treated with a crude extract of pupae of P. rapae. These results indicate that pierisin from the pupae of P. rapae induces apoptosis in human carcinoma cells.