An antibiotic isolated from the bacterium Streptomyces plicatus with antineoplastic activity. Plicamycin, also known as mithramycin, binds to the minor groove of DNA at GC-rich sites, resulting in inhibition of RNA synthesis; this agent also inhibits mRNA expression, resulting in a reduction in protein synthesis. In addition, plicamycin may inhibit bone resorption by down regulating transcription of c-src, an oncogene involved in bone metabolism and resorption. orA drug used to treat some types of testicular cancer. It is also used to treat a higher-than-normal amounts of calcium in the blood or urine. Plicamycin binds to DNA and prevents cells from making RNA and proteins. It is a type of antineoplastic antibiotic. Also called Mithracin and mithramycin.