Topological inactivation activity was according to a previously described method. 17 Antitumor activity in vitro JAR choriocarcinoma cells were maintained in an incubator supplied with a humidified atmosphere of 5% CO 2 at 37°C. The culture medium was DMEM containing 20 mM HEPES and 10% fetal bovine serum. The cell viability and proliferation were determined by quantitative 3-(4,5dimethylthiozol-2-yl)-2,5-diphenyltetrazolium bromide (MTT). A total of 3 × 10 4 cells/mL were applied into 96-well microtiter plates at 100 µL per well and exposed to PEGylated α-MMC, PEGylated MAP30, and un-PEGylated counterparts of 0.012, 0.06, 0.3, and 1.5 mg/mL at 24, 48, and 72 hours. Cells without drugs were used as controls. Each concentration was tested in quadruplicate. The determination procedure was carried out according to the previous description. 18 The optical density (OD) at 570 nm was measured using an ELISA plate reader (EL × 800, BIO-TEK, Atlanta, GA). Cell viability and proliferation were observed together with controls.