⁶⁴Cu Hypoxia Imaging Radiotracer Targeting the Human Copper Transporter

Area of Science:

• Biomedical imaging
• Radiochemistry
• Oncology

Background:

• Hypoxia imaging is crucial in oncology, cardiology, and neurology but faces challenges with diagnostic accuracy.
• Current hypoxia imaging biomarkers often have suboptimal signals, limiting clinical translation.

Purpose of the Study:

• To develop a novel Copper-64 (⁶⁴Cu)-based radiotracer for enhanced hypoxia detection.
• To evaluate the efficacy of ⁶⁴Cu-CysPhe in non-invasively imaging hypoxic tumors.

Main Methods:

• Developed a ⁶⁴Cu-based radiotracer, ⁶⁴Cu-CysPhe, utilizing the human copper transporter 1 (hCtr1) pathway.
• Performed in-vivo PET-MRI imaging in a murine breast cancer model.
• Conducted immunohistochemical analyses and compared with established radiotracers (⁶⁴Cu-ATSM, ¹⁸F-FDG).

Main Results:

• ⁶⁴Cu-CysPhe demonstrated selective accumulation in hypoxic tissues via the hCtr1 pathway.
• PET-MRI imaging showed high tumor-to-muscle ratios (>3.0) up to 24 hours post-injection in a murine breast cancer model.
• Immunohistochemistry confirmed preferential localization to hypoxic regions, distinguishing them from necrotic areas, and showed superior sensitivity compared to ⁶⁴Cu-ATSM and ¹⁸F-FDG.

Conclusions:

• ⁶⁴Cu-CysPhe is a promising novel radiotracer for non-invasive imaging of tumor hypoxia.
• The tracer's mechanism targets cellular copper uptake, enhancing signal and diagnostic accuracy.
• This development could significantly advance functional imaging in oncology.