Related Experiment Video
Updated: Jun 18, 2026
Preparing a 68Ga-labeled Arginine Glycine Aspartate RGD-peptide for Angiogenesis
Published on: January 7, 2019
Peptide-Based [68Ga]Ga Labeled PET Tracer for Tumor Imaging by Targeting Tumor-Associated Macrophages
Mingxing Huang1, Rang Wang1, Mufeng Li1
1Department of Nuclear Medicine, West China Hospital, Sichuan University, 37 Guoxue Alley, Chengdu 610041, China.
Abstract:
Tumor-associated macrophages (TAMs) are known to promote cancer development and metastasis. In this study, a TAMs-targeting peptide named M2pep was selected to investigate the feasibility of [68Ga]Ga-labeled M2pep as a noninvasive probe in targeted TAMs imaging. The peptide M2pep was conjugated with 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) and radiolabeled with 68Ga. The cellular uptake and binding assay were assessed in M2 macrophages and in the B16F10 cell line. Micro-PET imaging and a biodistribution study were performed on B16F10 tumor-bearing mice. High radiochemical purity [68Ga]Ga-DOTA-M2pep (>95%) was prepared and was stabilized in saline and bovine serum at 37 °C for 2 h. In vitro studies demonstrated high uptake of [68Ga]Ga-DOTA-M2pep in M2 macrophages, which was effectively blocked by the “cold” M2pep (free peptide). The micro-PET imaging and biodistribution study revealed that [68Ga]Ga-DOTA-M2pep reached the tumor site rapidly and showed high accumulation in the tumor at 1 h post-injection. In addition, the probe was rapidly cleared from the blood and mainly excreted via the kidneys, resulting in a high tumor/background ratio. Preclinical studies have shown that [68Ga]Ga-DOTA-M2pep specifically targets TAMs and might be a promising molecular probe for the noninvasive visualization of TAMs expression.
Insights
A novel [68Ga]Ga-labeled peptide, [68Ga]Ga-DOTA-M2pep, effectively targets tumor-associated macrophages (TAMs). This molecular probe shows promise for noninvasive TAMs imaging in cancer diagnostics.
Area of Science:
- Oncology
- Radiochemistry
- Molecular Imaging
Background:
- Tumor-associated macrophages (TAMs) are key drivers of cancer progression and metastasis.
- Targeting TAMs is a crucial strategy for cancer diagnosis and therapy.
- Noninvasive imaging of TAMs expression is needed for effective cancer management.
Purpose of the Study:
- To develop and evaluate [68Ga]Ga-labeled M2pep ([68Ga]Ga-DOTA-M2pep) as a molecular probe for noninvasive TAMs imaging.
- To assess the feasibility of using [68Ga]Ga-DOTA-M2pep for targeted imaging of TAMs in a preclinical cancer model.
Main Methods:
- Peptide M2pep was conjugated with DOTA and radiolabeled with Gallium-68 (68Ga).
- In vitro cellular uptake and binding assays were performed using M2 macrophages and B16F10 cells.
- In vivo studies involved micro-PET imaging and biodistribution analysis in B16F10 tumor-bearing mice.
Main Results:
- High radiochemical purity (>95%) of [68Ga]Ga-DOTA-M2pep was achieved and demonstrated stability.
- [68Ga]Ga-DOTA-M2pep showed high specific uptake in M2 macrophages in vitro.
- Micro-PET imaging revealed rapid tumor accumulation and high tumor-to-background ratios in vivo.
- The probe was quickly cleared from circulation and primarily excreted renally.
Conclusions:
- [68Ga]Ga-DOTA-M2pep specifically targets TAMs.
- This radiolabeled peptide is a promising molecular probe for noninvasive visualization of TAMs expression.
- The findings support the potential clinical utility of [68Ga]Ga-DOTA-M2pep in cancer imaging.
![Automated Preparation of [68Ga]Ga-3BP-3940 on a Synthesis Module for PET Imaging of the Tumor Microenvironment](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F68356.jpg&w=3840&q=50)
