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PET and MRI of metastatic peritoneal and pulmonary colorectal cancer in mice with human epidermal growth factor receptor 1-targeted 89Zr-labeled panitumumab.

ABSTRACT: UNLABELLED:Human epidermal growth factor receptor 1 (HER1) plays an important role in the pathogenesis of colorectal cancer. Panitumumab is an anti-HER1 monoclonal antibody approved for use in colorectal cancer. However, few data exist regarding HER1 status in the corresponding distant metastases, and little corresponding information is available regarding the localization of panitumumab at primary and metastatic lesions. The utility of PET and MRI using (89)Zr-panitumumab to assess the status of HER1 in distant metastases with different metastasis models is presented in this study. METHODS:In vivo biodistribution and PET studies were performed in HER1-expressing LS-174T and HER1-negative A375 tumor xenografts. Additionally, studies were performed in different models of intraperitoneal and pulmonary metastases. MRI studies were performed for metastatic models to characterize the targeting potential of (89)Zr-panitumumab at different lesion sites. RESULTS:HER1-mediated targeting was achieved in all HER1-expressing models. The LS-174T tumor area under the curve (AUC) was 3.7-fold greater than the AUC for A375. The LS-174T tumor AUC of 204.13 ± 9.67 was significantly greater (P < 0.001) than the LS-174T tumor AUC of 36.45 ± 1.39 obtained from mice coinjected with 0.1 mg of panitumumab for blocking the target. Differences were observed in 2 intraperitoneal models; tumor uptake in mice with a 3-d tumor burden was more than 2-fold greater than the mice with a 7-d tumor burden. PET and MRI studies revealed HER1-mediated tumor targeting in all metastatic models. However, significant differences were observed between different LS-174T tumor models. Peak tumor uptake of approximately 40 percentage injected dose per gram (%ID/g) was observed at 3-4 d after injection for the subcutaneous tumor model, in contrast to approximately 75 %ID/g at 2 d after injection for the thoracic tumors and approximately 95 %ID/g at 1-2 d after injection for the intraperitoneal tumors. CONCLUSION:The potential utility of (89)Zr-panitumumab in assessing HER1 status in distant metastases and understanding the variations in antibody uptake at different lesion sites is demonstrated in this study. (89)Zr-panitumumab can play a vital role in patient stratification and immunotherapy and therefore warrants further investigation for clinical translation.

SUBMITTER: Nayak TK

PROVIDER: S-EPMC3252203 | biostudies-literature | 2012 Jan

REPOSITORIES: biostudies-literature

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PET and MRI of metastatic peritoneal and pulmonary colorectal cancer in mice with human epidermal growth factor receptor 1-targeted 89Zr-labeled panitumumab.

Nayak Tapan K TK Garmestani Kayhan K Milenic Diane E DE Brechbiel Martin W MW

Journal of nuclear medicine : official publication, Society of Nuclear Medicine 20120101 1

<h4>Unlabelled</h4>Human epidermal growth factor receptor 1 (HER1) plays an important role in the pathogenesis of colorectal cancer. Panitumumab is an anti-HER1 monoclonal antibody approved for use in colorectal cancer. However, few data exist regarding HER1 status in the corresponding distant metastases, and little corresponding information is available regarding the localization of panitumumab at primary and metastatic lesions. The utility of PET and MRI using (89)Zr-panitumumab to assess the ...[more]

PMID: 22213822

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Project description:UNLABELLED:Tumor-associated macrophages (TAMs) are increasingly investigated in cancer immunology and are considered a promising target for better and tailored treatment of malignant growth. Although TAMs also have high diagnostic and prognostic value, TAM imaging still remains largely unexplored. Here, we describe the development of reconstituted high-density lipoprotein (rHDL)-facilitated TAM PET imaging in a breast cancer model. METHODS:Radiolabeled rHDL nanoparticles incorporating the long-lived positron-emitting nuclide (89)Zr were developed using 2 different approaches. The nanoparticles were composed of phospholipids and apolipoprotein A-I (apoA-I) in a 2.5:1 weight ratio. (89)Zr was complexed with deferoxamine (also known as desferrioxamine B, desferoxamine B), conjugated either to a phospholipid or to apoA-I to generate (89)Zr-PL-HDL and (89)Zr-AI-HDL, respectively. In vivo evaluation was performed in an orthotopic mouse model of breast cancer and included pharmacokinetic analysis, biodistribution studies, and PET imaging. Ex vivo histologic analysis of tumor tissues to assess regional distribution of (89)Zr radioactivity was also performed. Fluorescent analogs of the radiolabeled agents were used to determine cell-targeting specificity using flow cytometry. RESULTS:The phospholipid- and apoA-I-labeled rHDL were produced at 79% ± 13% (n = 6) and 94% ± 6% (n = 6) radiochemical yield, respectively, with excellent radiochemical purity (>99%). Intravenous administration of both probes resulted in high tumor radioactivity accumulation (16.5 ± 2.8 and 8.6 ± 1.3 percentage injected dose per gram for apoA-I- and phospholipid-labeled rHDL, respectively) at 24 h after injection. Histologic analysis showed good colocalization of radioactivity with TAM-rich areas in tumor sections. Flow cytometry revealed high specificity of rHDL for TAMs, which had the highest uptake per cell (6.8-fold higher than tumor cells for both DiO@Zr-PL-HDL and DiO@Zr-AI-HDL) and accounted for 40.7% and 39.5% of the total cellular DiO@Zr-PL-HDL and DiO@Zr-AI-HDL in tumors, respectively. CONCLUSION:We have developed (89)Zr-labeled TAM imaging agents based on the natural nanoparticle rHDL. In an orthotopic mouse model of breast cancer, we have demonstrated their specificity for macrophages, a result that was corroborated by flow cytometry. Quantitative macrophage PET imaging with our (89)Zr-rHDL imaging agents could be valuable for noninvasive monitoring of TAM immunology and targeted treatment.

Project description:Anti-HER1 monoclonal antibody (mAb), panitumumab (Vectibix) is a fully human mAb approved by the FDA for the treatment of epidermal growth factor receptor (EGFR, HER1)-expressing colorectal cancers. By combining the targeted specificity of panitumumab with the quantitative in vivo imaging capabilities of PET, we evaluated the potential of (89)Zr-DFO-panitumumab PET/CT imaging and performed non-invasive, in vivo imaging of HER1 expression and estimated human dosimetry.Panitumumab was radiolabeled with (89)Zr using a derivative of desferrioxamine (DFO-Bz-NCS) and with (111)In using CHX-A" DTPA as bifunctional chelators. Comparative biodistribution/dosimetry of both radiotracers was performed in non-tumor bearing athymic nude mice (n=2 females and n=2 males) over 1-week following i.v. injection of either using (89)Zr-DFO-panitumumab or (111)In-CHX-A"-DTPA-panitumumab. Micro-PET/CT imaging of female athymic nude mice bearing human breast cancer tumors (n=5 per tumor group) with variable HER1-expression very low (BT-474), moderate (MDA-MB-231), and very high (MDA-MB-468) was performed at over 1 week following i.v. injection of (89)Zr-DFO-panitumumab.Radiochemical yield and purity of (89)Zr-Panitumumab was >70% and >98% respectively with specific activity 150 ± 10 MBq/mg of panitumumab in a ~4 hr synthesis time. Biodistribution of (111)In-CHX-A" DTPA -panitumumab and (89)Zr-DFO-panitumumab in athymic non-tumor bearing nude mice displayed similar percent injected dose per gram of tissue with prominent accumulation of both tracers in the lymph nodes, a known clearance mechanism of panitumumab. Also exhibited was prolonged blood pool with no evidence of targeted accumulation in any organ. Human radiation dose estimates showed similar biodistributions with estimated human effective doses of 0.578 and 0.183 mSv/MBq for (89)Zr-DFO-panitumumab and (111)In-CHX-A"-DTPA-panitumumab, respectively. Given the potential quantitative and image quality advantages of PET, imaging of tumor bearing mice was only performed using (89)Zr-DFO-panitumumab. Immuno-PET imaging of (89)Zr-DFO-panitumumab in mice bearing breast cancer xenograft tumors with variable HER1 expression showed high tumor uptake (SUV >7) in the MDA-MB-468 high HER1-expressing mice and a strong correlation between HER1-expression level and tumor uptake (R(2)= 0.857, P < .001).(89)Zr-DFO-panitumumab can prepared with high radiochemical purity and specific activity. (89)Zr-DFO-panitumumab microPET/CT showed uptake corresponding to HER-1 expression. Due to poor clearance, initial dosimetry estimates suggest that only a low dose (89)Zr-DFO-panitumumab shows favorable human dosimetry; however due to high tumor uptake, the use of (89)Zr-DFO-panitumumab is expected to be clinically feasible.

Project description:To develop imaging and therapeutic agents, antibodies are often conjugated randomly to a chelator/radioisotope or drug using a primary amine (NH2) of lysine or sulfhydryl (SH) of cysteine. Random conjugation to NH2 or SH groups can require extreme conditions and may affect target recognition/binding and must therefore be tested. In the present study, nimotuzumab was site-specifically labeled using ∆N-SpyCatcher/SpyTag with different chelators and radiometals. Nimotuzumab is a well-tolerated anti-EGFR antibody with low skin toxicities. First, ΔN-SpyCatcher was reduced using tris(2-carboxyethyl)phosphine (TCEP), which was followed by desferoxamine-maleimide (DFO-mal) conjugation to yield a reactive ΔN-SpyCatcher-DFO. The ΔN-SpyCatcher-DFO was reacted with nimotuzumab-SpyTag to obtain stable nimotuzumab-SpyTag-∆N-SpyCatcher-DFO. Radiolabeling was performed with 89Zr, and the conjugate was used for the in vivo microPET imaging of EGFR-positive MDA-MB-468 xenografts. Similarly, ∆N-SpyCatcher was conjugated to an eighteen-membered macrocyclic chelator macropa-maleimide and used to radiolabel nimotuzumab-SpyTag with actinium-225 (225Ac) for in vivo radiotherapy studies. All constructs were characterized using biolayer interferometry, flow cytometry, radioligand binding assays, HPLC, and bioanalyzer. MicroPET/CT imaging showed a good tumor uptake of 89Zr-nimotuzumab-SpyTag-∆N-SpyCatcher with 6.0 ± 0.6%IA/cc (n = 3) at 48 h post injection. The EC50 of 225Ac-nimotuzumab-SpyTag-∆N-SpyCatcher and 225Ac-control-IgG-SpyTag-∆N-SpyCatcher against an EGFR-positive cell-line (MDA-MB-468) was 3.7 ± 3.3 Bq/mL (0.04 ± 0.03 nM) and 18.5 ± 4.4 Bq/mL (0.2 ± 0.04 nM), respectively. In mice bearing MDA-MB-468 EGFR-positive xenografts, 225Ac-nimotuzumab-SpyTag-∆N-SpyCatcher significantly (p = 0.0017) prolonged the survival of mice (64 days) compared to 225Ac-control IgG (28.5 days), nimotuzumab (28.5 days), or PBS-treated mice (30 days). The results showed that the conjugation and labeling using SpyTag/∆N-SpyCatcher to nimotuzumab did not significantly (p > 0.05) alter the receptor binding of nimotuzumab compared with a non-specific conjugation approach. 225Ac-nimotuzumab-SpyTag-∆N-SpyCatcher was effective in vitro and in an EGFR-positive triple negative breast cancer xenograft model.

Project description:INTRODUCTION:Chimeric antigen receptor (CAR) T-cells have been recently developed and are producing impressive outcomes in patients with hematologic malignancies. However, there is no standardized method for cell trafficking and in vivo CAR T-cell monitoring. We assessed the feasibility of real-time in vivo 89Zr-p-Isothiocyanatobenzyl-desferrioxamine (Df-Bz-NCS, DFO) labeled CAR T-cell trafficking using positron emission tomography (PET). RESULTS:The 89Zr-DFO radiolabeling efficiency of Jurkat/CAR and human peripheral blood mononuclear cells (hPBMC)/CAR T-cells was 70%-79%, and cell radiolabeling activity was 98.1-103.6 kBq/106 cells. Cell viability after radiolabeling was >95%. Cell proliferation was not significantly different during the early period after radiolabeling, compared with unlabeled cells; however, the proliferative capacity decreased over time (day 7 after labeling). IL-2 or IFN-? secretion was not significantly different between unlabeled and labeled CAR T-cells. PET/magnetic resonance imaging in the xenograft model showed that most of the 89Zr-DFO-labeled Jurkat/CAR T-cells were distributed in the lung (24.4% ± 3.4%ID) and liver (22.9% ± 5.6%ID) by one hour after injection. The cells gradually migrated from the lung to the liver and spleen by day 1, and remained stable in these sites until day 7 (on day 7: lung 3.9% ± 0.3%ID, liver 36.4% ± 2.7%ID, spleen 1.4% ± 0.3%ID). No significant accumulation of labeled cells was identified in tumors. A similar pattern was observed in ex vivo biodistributions on day 7 (lung 3.0% ± 1.0%ID, liver 19.8% ± 2.2%ID, spleen 2.3% ± 1.7%ID). 89Zr-DFO-labeled hPBMC/CAR T-cells showed a similar distribution, compared with Jurkat/CAR T-cells, on serial PET images. CAR T cell distribution was cross-confirmed by flow cytometry, Alu polymerase chain reaction, and immunohistochemistry. CONCLUSION:Real-time in vivo cell trafficking is feasible using PET imaging of 89Zr-DFO-labeled CAR T-cells. This can be used to investigate cellular kinetics, initial in vivo biodistribution, and safety profiles in future CAR T-cell development.

Dataset Information

PET and MRI of metastatic peritoneal and pulmonary colorectal cancer in mice with human epidermal growth factor receptor 1-targeted 89Zr-labeled panitumumab.

Publications

PET and MRI of metastatic peritoneal and pulmonary colorectal cancer in mice with human epidermal growth factor receptor 1-targeted 89Zr-labeled panitumumab.

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