Abstract: The invention relates to the synthesis of a second-generation camptothecin glucuronide prodrug (BQC-G) of a potent anticancer camptothecin derivative 5,6-dihydro-4H-benzo[de]quinoline-camptothecin (BQC). BQC-G was over 4000 times more water soluble than BQC, displayed good stability in human plasma and was an excellent substrate for enzymatic hydrolysis by bacterial and human ?-glucuronidases. BQC-G was about 30 times less toxic than BQC, but was as toxic as BQC after hydrolysis of the glucuronide moiety by ?-glucuronidase. In the presence of human serum albumin, BQC-G displayed lower cytotoxicity (IC50=1080 nM) but could be activated by ?-glucuronidase to display potent activity (IC50=13.3 nM).

Abstract: The invention relates to the synthesis of a second-generation camptothecin glucuronide prodrug (BQC-G) of a potent anticancer camptothecin derivative 5,6-dihydro-4H-benzo[de]quinoline-camptothecin (BQC). BQC-G was over 4000 times more water soluble than BQC, displayed good stability in human plasma and was an excellent substrate for enzymatic hydrolysis by bacterial and human ?-glucuronidases. BQC-G was about 30 times less toxic than BQC, but was as toxic as BQC after hydrolysis of the glucuronide moiety by ?-glucuronidase. In the presence of human serum albumin, BQC-G displayed lower cytotoxicity (IC50=1080 nM) but could be activated by ?-glucuronidase to display potent activity (IC50=13.3 nM).

Abstract: A number of human beta-glucuronidase variants having higher enzymatic activity at physiological pH as compared with wild-type beta-glucuronidase and uses thereof in prodrug therapy. Also disclosed herein is a method for identifying enzyme variants having elevated enzymatic activity using a mammalian surface display system.