Radiochemical Evaluation and In Vitro Assessment of the Targeting Ability of a Novel 99mTc-HYNIC-RGD for U87MG Human Brain Cancer Cells

Background: Labeled RGD peptide that specifically targets ανβ3 integrin has great potential for the early diagnosis of malignant tumors.αvβ3 integrin receptors appear specifically more on the surface of glioblastoma (malignant glioma) cells rather than normal cells. Objective: The aim of this study was to identify a novel RGD that can be radiolabeled with 99mTc with in vitro assessment of its targeting ability for U87MG human brain cancer cells. Method: Novel RGD was designed by Amino Acid retro-inversion technique. The peptide HYNIC conjugate was radiolabeled with 99mTc at 95°C for 10 min and radiochemical analysis was performed using ITLC and HPLC methods. The stability of the radiopeptide was checked in the presence of human serum at 37°C up to 24 h. Binding properties and internalization were studied with U87MG cells. Results: Novel HYNIC-RGD has shown high radiochemical purity over 98%. Radioconjugate binding and internalization in U87MG cells were high and specific (13.96% and 12.38% at 4 h respectively). The radiolabeled peptide revealed good affinity for glioblastoma cells (Kd=1.46± 0.26nM). Conclusion: The in vitro study demonstrated the targeting ability of novel 99mTc-HYNIC-RGD for glioblastoma cells. Therefore, more in vivo studies are required.