Time-response analysis showing percentage changes in <sup>31</sup>P-NMR-detected metabolite levels following treatment of KNS42 pediatric glioblastoma cells with PI-103 (5×GI<sub>50</sub>).

<p>Data are expressed as percentage of treated to control (% T/C) and presented as the mean ± SD, n≥3.</p><p>PE in KNS42 cells was not consistently detectable due to the low levels of this metabolite and was not affected by treatment with PI-103.</p><p>Glycerophosphoethanolamine (GPE) level was not affected by treatment with PI-103.</p><p>Two-tailed unpaired <i>t</i> test was used to compare results in treated cells to controls.</p><p>*P<0.05.</p>