Therapy-Induced Changes in CXCR4 Expression in Tumor Xenografts Can Be Monitored Noninvasively with N-[11C]Methyl-AMD3465 PET

Purpose Chemokine CXCL12 and its receptor CXCR4 are constitutively overexpressed in human cancers. The CXCL12-CXCR4 signaling axis plays an important role in tumor progression and metastasis, but also in treatment-induced recruitment of CXCR4-expressing cytotoxic immune cells. Here, we aimed to demo...

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Bibliographic Details
Published in:Molecular imaging and biology 2020-08, Vol.22 (4), p.883-890
Main Authors: Hartimath, SV, Draghiciu, O., Daemen, T, Nijman, H.W., van Waarde, A., Dierckx, R.A.J.O., de Vries, E.F.J.
Format: Article
Language:English
Subjects:
Alpha rays
Animals
Antigens
Biomarkers
Cervical cancer
Chemokines
Chemotaxis
CXCL12 protein
CXCR4 protein
Cytotoxicity
Density
Feasibility studies
Human papillomavirus
Imaging
Immune system
Immunization
Inoculation
Irradiation
Medical imaging
Medicine
Medicine & Public Health
Metastases
Positron emission
Positron emission tomography
Radiation therapy
Radiology
Receptors
Research Article
Tomography
Tumors
Vaccines
Xenografts
Xenotransplantation
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Summary:Purpose Chemokine CXCL12 and its receptor CXCR4 are constitutively overexpressed in human cancers. The CXCL12-CXCR4 signaling axis plays an important role in tumor progression and metastasis, but also in treatment-induced recruitment of CXCR4-expressing cytotoxic immune cells. Here, we aimed to demonstrate the feasibility of N-[ 11 C]methyl-AMD3465 positron emission tomography (PET) to monitor changes in CXCR4 density in tumors after single-fraction local radiotherapy or in combination with immunization. Procedure TC-1 cells expressing human papillomavirus antigens E6 and E7 were inoculated into the C57BL/6 mice subcutaneously. Two weeks after tumor cell inoculation, mice were irradiated with a single-fraction 14-Gy dose of X-ray. One group of irradiated mice was immunized with an alpha-viral vector vaccine, SFVeE6,7, and another group received daily injections of the CXCR4 antagonist AMD3100 (3 mg/kg -intraperitoneal (i.p.)). Seven days after irradiation, all animals underwent N-[ 11 C]methyl-AMD3465 PET. Results PET imaging showed N-[ 11 C]methyl-AMD3465 uptake in the tumor of single-fraction irradiated mice was nearly 2.5-fold higher than in sham-irradiated tumors (1.07 ± 0.31 %ID/g vs. 0.42 ± 0.05 % ID/g, p < 0.01). The tumor uptake was further increased by 4-fold (1.73 ± 0.17 % ID/g vs 0.42 ± 0.05 % ID/g, p < 0.01) in mice treated with single-fraction radiotherapy in combination with SFVeE6,7 immunization. Administration of AMD3100 caused a 4.5-fold reduction in the tracer uptake in the tumor of irradiated animals (0.24 ± 0.1 % ID/g, p < 0.001), suggesting that tracer uptake is indeed due to CXCR4-mediated chemotaxis. Conclusion This study demonstrates the feasibility of N-[ 11 C]methyl-AMD3465 PET imaging to monitor treatment-induced changes in the density of CXCR4 receptors in tumors and justifies further evaluation of CXCR4 as a potential imaging biomarker for evaluation of anti-tumor therapies.
ISSN:1536-1632
1860-2002
DOI:10.1007/s11307-019-01447-x