Peptide-based PET imaging agent of tumor TIGIT expression

Area of Science:

• Nuclear Medicine
• Immunotherapy
• Oncology

Background:

• Elevated TIGIT expression in the tumor microenvironment correlates with better therapeutic response to TIGIT-based immunotherapy.
• Non-invasive methods to detect tumor TIGIT expression are crucial for predicting treatment outcomes.

Purpose of the Study:

• To develop a peptide-based PET imaging agent for non-invasive detection of TIGIT expression.
• To evaluate the efficacy of 68Ga-DOTA-DTBP-3 in preclinical models.

Main Methods:

• Development of a novel peptide (D-TBP-3) radiolabeled with 68Ga via a DOTA chelator.
• In vitro evaluation of affinity and stability.
• In vivo assessment using micro-PET, biodistribution, and immunohistochemistry in tumor-bearing mice.

Main Results:

• 68Ga-DOTA-DTBP-3 demonstrated specific targeting of TIGIT in 4T1 tumor-bearing mice.
• Highest uptake was observed at 0.5 hours post-injection.
• In vitro studies confirmed affinity for TIGIT and stability in serum.

Conclusions:

• 68Ga-DOTA-DTBP-3 shows potential for non-invasive detection of tumor TIGIT expression.
• The agent can aid in timely assessment of immune checkpoint blockade therapy effectiveness.