journal contribution
posted on 2023-04-03, 15:05 authored by Minjee Kim, Daniel J. Ma, David Calligaris, Shuangling Zhang, Ryan W. Feathers, Rachael A. Vaubel, Isabelle Meaux, Ann C. Mladek, Karen E. Parrish, Fang Jin, Cedric Barriere, Laurent Debussche, James Watters, Shulan Tian, Paul A Decker, Jeanette E. Eckel-Passow, Gaspar J. Kitange, Aaron J. Johnson, Ian F. Parney, Panos Z. Anastasiadis, Nathalie Y.R. Agar, William F. Elmquist, Jann N. Sarkaria Fig. S1: MDM2 transcript expression. RNA extracted from flank tumor xenografts from 51 PDX models was assessed by qRT-PCR for MDM2 expression in pooled triplicate samples and compared to expression in normal brain (NB). Fig. S2: MDM2 Amplification in PDX lines. Copy-number profiles were generated from whole exome sequencing of flank xenografts. MDM2 exons are highlighted in red. GBM10, GBM12, and GBM102 show normal MDM2 copy number. GBM108 and GBM143 demonstrate high-level amplification of MDM2. Fig. S3: Apoptosis by TUNEL assay in GBM108. Established flank tumor xenografts were randomized and treated for 5 days with placebo (n=5 mice) versus 50 mg/kg SAR405838 (n=5 mice). Tumor samples were then processed for TUNEL staining. TUNEL-positive cells were quantitated in six high-powered fields (HPF) for each sample. Results are plotted as mean and standard error of the mean. * P<0.05, ** P<0.01, *** P<0.001. Fig. S4: Blood brain barrier integrity in orthotopic tumors. Near-moribund mice with orthotopic GBM108 tumors were injected with TexasRed-3 kDa dextran conjugate 10 min before euthanasia and processed for cresyl violet and fluorescent microscopy on serial histology sections. Accumulation of TR-dextran within the tumor reflects disruption of the BBB. Results presented are representative of five mice analyzed. Scale bar = 500 µm. Fig. S5: VEGFA expression in GBM108 models. Short term explant cultures from parental GBM108, GBM108-empty vector (EV), and GBM108VEGFA were processed for an ELISA to measure VEGFA levels. One-way ANOVA. * P<0.05, ** P<0.01, *** P<0.001. Fig. S6: Effects of VEGFA expression on SAR405838 sensitivity. Short-term explant cultures from GBM108-Vector and GBM108-VEGFA were treated with indicated concentrations of SAR405838 for 24 hours and then relative cell number analyzed in a CyQuant assay. Fig. S7: Spatial distribution of SAR405838 in GBM108-Vector and GBM108-VEGFA intracranial tumors by MALDI-MSI.
Funding
National Institutes of Health
MIT/Mayo Physical Sciences Center
History
ARTICLE ABSTRACT
Controversy exists surrounding whether heterogeneous disruption of the blood–brain barrier (BBB), as seen in glioblastoma (GBM), leads to adequate drug delivery sufficient for efficacy in GBM. This question is especially important when using potent, targeted agents that have a poor penetration across an intact BBB. Efficacy of the murine double minute-2 (MDM2) inhibitor SAR405838 was tested in patient-derived xenograft (PDX) models of GBM. In vitro efficacy of SAR405838 was evaluated in PDX models with varying MDM2 expression and those with high (GBM108) and low (GBM102) expression were evaluated for flank and orthotopic efficacy. BBB permeability, evaluated using TexasRed-3 kDa dextran, was significantly increased in GBM108 through VEGFA overexpression. Drug delivery, MRI, and orthotopic survival were compared between BBB-intact (GBM108-vector) and BBB-disrupted (GBM108-VEGFA) models. MDM2-amplified PDX lines with high MDM2 expression were sensitive to SAR405838 in comparison with MDM2 control lines in both in vitro and heterotopic models. In contrast with profound efficacy observed in flank xenografts, SAR405838 was ineffective in orthotopic tumors. Although both GBM108-vector and GBM108-VEGFA readily imaged on MRI following gadolinium contrast administration, GBM108-VEGFA tumors had a significantly enhanced drug and gadolinium accumulation, as determined by MALDI-MSI. Enhanced drug delivery in GBM108-VEGFA translated into a marked improvement in orthotopic efficacy. This study clearly shows that limited drug distribution across a partially intact BBB may limit the efficacy of targeted agents in GBM. Brain penetration of targeted agents is a critical consideration in any precision medicine strategy for GBM. Mol Cancer Ther; 17(9); 1893–901. ©2018 AACR.
