Enhancement by caffeine of neocarzinostatin cytotoxicity in murine leukemia L1210 cells.

Posttreatment incubation with nontoxic doses of caffeine resulted in enhancement of cell lethality and inhibition of cell growth in L1210 mouse leukemia cells which had been exposed to a protein antibiotic, neocarzinostatin. In addition, caffeine treatment appeared to inhibit the eventual maturation of newly synthesized DNA in L1210 cells following exposure to this antibiotic. These results, indicating the existence of caffeine-sensitive repair in L1210 leukemia cells treated with neocarzinostatin, provide further evidence for DNA damage as a mechanism of the cytocidal action of the antibiotic.