Induction of urokinase-type plasminogen activator by the anthracycline antibiotic in human RC-K8 lymphoma and H69 lung-carcinoma cells

Current evidence has suggested the possible involvement of ROS as signaling messengers in IL-1β- or LPS-induced gene expression. We previously reported that both IL-1β and LPS induce uPA in RC-K8 human lymphoma cells. Here, we provide evidence that ROS-generating anthracycline antibiotics, including doxorubicin and aclarubicin, upregulate uPA expression in 2 human malignant cell lines, RC-K8 and H69 small-cell lung-carcinoma cells. Both doxorubicin and aclarubicin markedly increased uPA accumulation in RC-K8- and H69-conditioned medium in a dose-dependent manner. In each case, maximal induction was observed at a sublethal concentration, i.e., at a concentration where cell growth was slightly inhibited. Both doxorubicin and aclarubicin increased uPA mRNA levels, and induction in each case reached the maximal level 9 hr after stimulation. Doxorubicin barely changed the half-life of uPA mRNA and activated uPA gene transcription. Antioxidants such as NAC and PDTC inhibited doxorubicin-induced uPA mRNA accumulation. Microarray analysis, using Human Cancer CHIP version 2 (Takara Shuzo, Kyoto, Japan), in which 425 human cancer-related genes were spotted on glass plates, revealed that uPA is 1 of 3 genes that were clearly upregulated in H69 cells by doxorubicin stimulation. These findings suggest that the anthracycline induces uPA in human malignant cells by activating gene transcription in which ROS may be involved. Therefore, by upregulating uPA expression, the anthracycline may influence many biologic cell functions mediated by the uPA/plasmin system.