(99m)Tc-labeled SWL specific peptide for targeting EphA2 receptor

Area of Science:

• Oncology
• Molecular Imaging
• Radiochemistry

Background:

• EphA2 receptor tyrosine kinase is overexpressed in aggressive cancers.
• SWL peptide exhibits high binding affinity to EphA2.
• Targeted molecular imaging probes are crucial for cancer detection.

Purpose of the Study:

• To develop and evaluate a novel peptide-based SPECT imaging probe, 99mTc-HYNIC-SWL, for EphA2-positive tumors.
• To assess the in vitro and in vivo specificity and efficacy of 99mTc-HYNIC-SWL for EphA2-targeted imaging.

Main Methods:

• Radiolabeling of SWL peptide with 99mTc via HYNIC.
• Immunofluorescence staining to confirm EphA2 expression in cancer cell lines.
• In vitro saturation binding assays.
• In vivo SPECT imaging and biodistribution studies in tumor-bearing mice.

Main Results:

• 99mTc-HYNIC-SWL demonstrated high binding affinity to EphA2-expressing A549 cells (KD=2.6±0.7nM).
• SPECT imaging revealed significantly higher uptake in A549 tumors compared to OCM-1 tumors with low EphA2 expression.
• Tumor uptake was significantly reduced by co-administration of unlabeled SWL, confirming EphA2 specificity.

Conclusions:

• 99mTc-HYNIC-SWL effectively targets EphA2-positive tumors.
• The probe enables noninvasive investigation of EphA2 expression using SPECT imaging.
• 99mTc-HYNIC-SWL is a promising molecular imaging agent for EphA2-driven cancers.