18F-FET microPET and microMRI for anti-VEGF and anti-PlGF response assessment in an orthotopic murine model of human glioblastoma

TY - JOUR

T1 - 18F-FET microPET and microMRI for anti-VEGF and anti-PlGF response assessment in an orthotopic murine model of human glioblastoma

AU - Nedergaard, Mette Kjoelhede

AU - Michaelsen, Signe Regner

AU - Urup, Thomas

AU - Broholm, Helle

AU - El Ali, Henrik

AU - Poulsen, Hans Skovgaard

AU - Stockhausen, Marie-Thérése

AU - Kjaer, Andreas

AU - Lassen, Ulrik

PY - 2015/2/13

Y1 - 2015/2/13

N2 - BACKGROUND: Conflicting data exist for anti-cancer effects of anti-placental growth factor (anti-PlGF) in combination with anti-VEGF. Still, this treatment combination has not been evaluated in intracranial glioblastoma (GBM) xenografts. In clinical studies, position emission tomography (PET) using the radiolabeled amino acid O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) and magnetic resonance imaging (MRI) add complementary but distinct information about glioma growth; however, the value of 18F-FET MicroPET combined with MicroMRI has not been investigated preclinically. Here we examined the use of 18F-FET MicroPET and MicroMRI for evaluation of anti-VEGF and anti-PlGF treatment response in GBM xenografts.METHODS: Mice with intracranial GBM were treated with anti-VEGF, anti-PlGF + anti-VEGF or saline. Bioluminescence imaging (BLI), 18F-FET MicroPET and T2-weighted (T2w)-MRI were used to follow tumour development. Primary end-point was survival, and tumours were subsequently analysed for Ki67 proliferation index and micro-vessel density (MVD). Further, PlGF and VEGFR-1 expression were examined in a subset of the xenograft tumours and in 13 GBM patient tumours.RESULTS: Anti-VEGF monotherapy increased survival and decreased 18F-FET uptake, BLI and MVD, while no additive effect of anti-PlGF was observed. 18F-FET SUV max tumour-to-brain (T/B) ratio was significantly lower after one week (114 ± 6%, n = 11 vs. 143 ± 8%, n = 13; p = 0.02) and two weeks of treatment (116 ± 12%, n = 8 vs. 190 ± 24%, n = 5; p = 0.02) in the anti-VEGF group as compared with the control group. In contrast, T2w-MRI volume was unaffected by anti-VEGF. Gene expression of PlGF and VEGFR-1 in xenografts was significantly lower than in patient tumours.CONCLUSION: 18F-FET PET was feasible for anti-angiogenic response evaluation and superior to T2w-MRI; however, no additive anti-cancer effect of anti-PlGF and anti-VEGF was observed. Thus, this study supports use of 18F-FET PET for response evaluation in future studies.

AB - BACKGROUND: Conflicting data exist for anti-cancer effects of anti-placental growth factor (anti-PlGF) in combination with anti-VEGF. Still, this treatment combination has not been evaluated in intracranial glioblastoma (GBM) xenografts. In clinical studies, position emission tomography (PET) using the radiolabeled amino acid O-(2-18F-fluoroethyl)-L-tyrosine (18F-FET) and magnetic resonance imaging (MRI) add complementary but distinct information about glioma growth; however, the value of 18F-FET MicroPET combined with MicroMRI has not been investigated preclinically. Here we examined the use of 18F-FET MicroPET and MicroMRI for evaluation of anti-VEGF and anti-PlGF treatment response in GBM xenografts.METHODS: Mice with intracranial GBM were treated with anti-VEGF, anti-PlGF + anti-VEGF or saline. Bioluminescence imaging (BLI), 18F-FET MicroPET and T2-weighted (T2w)-MRI were used to follow tumour development. Primary end-point was survival, and tumours were subsequently analysed for Ki67 proliferation index and micro-vessel density (MVD). Further, PlGF and VEGFR-1 expression were examined in a subset of the xenograft tumours and in 13 GBM patient tumours.RESULTS: Anti-VEGF monotherapy increased survival and decreased 18F-FET uptake, BLI and MVD, while no additive effect of anti-PlGF was observed. 18F-FET SUV max tumour-to-brain (T/B) ratio was significantly lower after one week (114 ± 6%, n = 11 vs. 143 ± 8%, n = 13; p = 0.02) and two weeks of treatment (116 ± 12%, n = 8 vs. 190 ± 24%, n = 5; p = 0.02) in the anti-VEGF group as compared with the control group. In contrast, T2w-MRI volume was unaffected by anti-VEGF. Gene expression of PlGF and VEGFR-1 in xenografts was significantly lower than in patient tumours.CONCLUSION: 18F-FET PET was feasible for anti-angiogenic response evaluation and superior to T2w-MRI; however, no additive anti-cancer effect of anti-PlGF and anti-VEGF was observed. Thus, this study supports use of 18F-FET PET for response evaluation in future studies.

KW - Animals

KW - Antineoplastic Agents

KW - Antineoplastic Combined Chemotherapy Protocols

KW - Brain Neoplasms

KW - Cell Line, Tumor

KW - Cell Transformation, Neoplastic

KW - Drug Synergism

KW - Female

KW - Gene Expression Regulation, Neoplastic

KW - Glioblastoma

KW - Humans

KW - Magnetic Resonance Imaging

KW - Membrane Proteins

KW - Mice

KW - Microvessels

KW - Multimodal Imaging

KW - Optical Imaging

KW - Positron-Emission Tomography

KW - RNA, Messenger

KW - Survival Analysis

KW - Tomography, X-Ray Computed

KW - Treatment Outcome

KW - Tyrosine

KW - Vascular Endothelial Growth Factor A

KW - Vascular Endothelial Growth Factor Receptor-1

U2 - 10.1371/journal.pone.0115315

DO - 10.1371/journal.pone.0115315

M3 - Journal article

C2 - 25680186

SN - 1932-6203

VL - 10

SP - 1

EP - 16

JO - P L o S One

JF - P L o S One

IS - 2

M1 - e0115315

ER -