Patched targeting peptides for imaging and treatment of hedgehog positive breast tumors

Area of Science:

• Oncology
• Molecular Imaging
• Biochemistry

Background:

• High tumor hedgehog expression correlates with poor prognosis in invasive ductal carcinoma.
• Sonic hedgehog signaling pathway plays a role in cancer progression.
• PTCH-binding peptides show potential for growth inhibition in activated hedgehog signaling tumors.

Purpose of the Study:

• To investigate the growth inhibitory effects of PTCH-binding peptides in breast cancer cells.
• To evaluate these peptides as molecular imaging probes for tracking hedgehog pathway activity.
• To assess changes in hedgehog pathway expression following chemotherapy.

Main Methods:

• Treatment of breast cancer cell lines with PTCH-blocking peptides.
• In vitro uptake studies with FITC- and (99m)Tc-labeled peptide conjugates.
• In vivo imaging studies using (99m)Tc-labeled peptides in tumor models.
• Correlation analysis of patched receptor expression and radiotracer uptake.

Main Results:

• Significant growth inhibition observed in breast cancer cells treated with PTCH-blocking peptides.
• Demonstrated in vitro uptake and in vivo tumor accumulation of radiolabeled peptide conjugates.
• Increased patched receptor expression post-treatment correlated with enhanced tumor radiotracer uptake.
• (99m)Tc-labeled peptides effectively imaged patched receptor in vivo.

Conclusions:

• Peptides binding the sonic hedgehog docking site in patched receptor correlate with patched expression and can be used for in vivo imaging.
• Radiolabeled peptides show potential for monitoring hedgehog signaling pathway activity.
• These agents may serve to evaluate response to anti-cancer therapies in breast cancer.