Mechanism of action of chounghwamycin A

The mechanism of action of chounghwamycin A to tumor cells resembles that of actinomycin D, preferentially inhibiting the synthesis of RNA. The interaction of chounghwamycin A with DNA was studied, and the results indicated that chounghwamycin A could not cause any scission in tested DNA. However, an induced mobility shift of the DNA in agarose gel electrophoresis was observed. When the concentration of chounghwamycin A gradually increased, the migration rate of closed circular form DNA is gradually slowed. At a critical concentration of chounghwamycin A, 15.6 micrograms/ml, the migration rate of closed circular form DNA reaches its minimum value. As more choungwamycin A is added, the mobility of the closed circular DNA increases gradually again, suggesting that the intercalation of chounghwamycin A in DNA is the primary mechanism of its action against tumor cells.