Synthesis and Preclinical Evaluation of Dual-Targeted Molecular Tracer for Positron Emission Tomography Imaging of Programmed Cell Death Ligand-1 and Integrin α_vβ₃

Dual-targeting strategies have shown considerable potential in improving the imaging contrast and specificity toward tumor tissues. In this study, we synthesized a dual-targeted tracer, <b>[</b> ^<b>68</b> <b>Ga]-Ga-NOTA-IMB-RGD</b>, which synergistically targeted programmed cell death ligand-1 (PD-L1) and integrin α_vβ₃. The tracer was produced with high radiochemical purity (>95%) and radiochemical yield (>95%). <i>In vitro</i> cellular uptake studies revealed that <b>[</b> ^<b>68</b> <b>Ga]-Ga-NOTA-IMB-RGD</b> exhibited high binding affinity for both PD-L1 and α_vβ₃, resulting in significantly higher uptake in PD-L1- and α_vβ₃-positive cells (U87, A375-hPD-L1, B16-F10, and MC38) compared to α_vβ₃-positive (A375) or PD-L1- and α_vβ₃-negative (LLC) cells. <i>In vivo</i> imaging of <b>[</b> ^<b>68</b> <b>Ga]-Ga-NOTA-IMB-RGD</b> in tumor-bearing mice revealed high and specific tumor uptake in double-positive tumors, modest tumor uptake in single-positive tumors, and low uptake in double-negative tumors, indicating strong binding to both PD-L1 and α_vβ₃ <i>in vivo</i>. <i>Ex vivo</i> tissue analysis further validated the high specificity and sensitivity of <b>[</b> ^<b>68</b> <b>Ga]-Ga-NOTA-IMB-RGD</b> in detecting tumors coexpressing PD-L1 and α_vβ₃. Importantly, <b>[</b> ^<b>68</b> <b>Ga]-Ga-NOTA-IMB-RGD</b> exhibited enhanced tumor uptake and retention compared to both PD-L1-targeted and α_vβ₃-targeted tracers in the same tumor models. In conclusion, the dual-targeted tracer <b>[</b> ^<b>68</b> <b>Ga]-Ga-NOTA-IMB-RGD</b> was successfully prepared and showed significantly specific targeting of both PD-L1 and α_vβ₃ <i>in vivo</i>, offering promising potential for clinical translation.