A novel AT1R-targeted near-infrared fluorescent probe enables intraoperative visualization and resection in hepatocellular carcinoma.

Despite ongoing advancements in therapeutic strategies, hepatocellular carcinoma (HCC) remains linked to a poor prognosis and high mortality rates, primarily owing to its aggressive biological behavior and significant potential for recurrence. Near-infrared fluorescence (NIRF)-guided surgery has become a gold-standard curative intervention for HCC; however, its clinical efficacy is markedly compromised by the limited availability of HCC-targeted NIRF probes. In this study, a novel NIRF molecular probe, MPA-Ang II-df, was constructed by conjugating the NIR dye MPA with a targeting ligand for the angiotensin II type 1 receptor (AT1R), a protein that is overexpressed in HCC. The targeting capability of this probe was systematically evaluated.

By conjugating a fluorescent moiety to the AT1R-targeting ligand Ang II-df, the resulting probe demonstrated high selectivity and specificity for AT1R-positive HCC tumor cells and tissues, both in vitro and in vivo. Ex vivo biodistribution analysis revealed prominent and target-specific accumulation of MPA-Ang II-df in AT1R-positive HCC tumor tissues, with minimal uptake in non-target organs. This resulted in tumor-to-background ratios (TBRs) of 5.7 ± 0.1, 18.1 ± 0.3, 15.5 ± 0.7, 21.6 ± 1.0, and 20.5 ± 0.3 for the tumor compared to the liver, heart, spleen, pancreas, and colorectal tissue in the Huh-7 subcutaneous xenograft model, respectively, at 10 h post-injection.

Furthermore, quantitative assessments confirmed high TBRs for MPA-Ang II-df, with values of 2.6 ± 0.3 and 4.4 ± 0.8 in orthotopic and bone-metastasized Huh-7 tumor models, respectively, facilitating precise delineation of tumor margins to guide intraoperative resection. Considering its rapid targeting capability, sustained retention profile, and accurate demarcation of tumor margins in orthotopic and bone-metastatic Huh-7 tumor models, MPA-Ang II-df emerges as a promising AT1R-targeted fluorescent contrast agent, potentially broadening the range of HCC fluorescent probes available for surgical navigation.