Effects of cucurbitacin I on cerebrospinal fluid stimulation of leptomeningeal and meningioma cell DNA synthesis. a. Cells from 17 (L1), 20 (L2) and 22 (L3) wk fetal leptomeninges (L), were treated with CSF without or with cucurbitacin I (250 nM) for 72 hrs. CyQUANT analysis of DNA measured with a fluorescence microplate reader with filters appropriate for ~480 nm excitation and ~520 nm emission maxima. Changes in DNA fluorescence correlate with cell proliferation. C = control, CSF = cerebrospinal fluid. * P < 0.05, *** P < 0.005, **** P < 0.001, ***** P < 0.0005. b. Cells from WHO grade I (M1-M3) and WHO grade II (M4-M5) meningiomas were treated as above. * P < 0.05, *** P < 0.005, **** P < 0.001, ***** P < 0.0005.