Peptide multimer for early detection of hepatocellular carcinoma

The incidence of hepatocellular carcinoma (HCC) is rising rapidly worldwide. In the U.S., this cancer is growing at a rate faster than that of any other cancer. New biomarkers specific for HCC tissue targets are critically needed to develop improved diagnostic and therapeutic strategies and better manage the increasing tumor burden. While alpha fetoprotein (AFP) is a common serological marker for HCC, no tissue targets are currently being used as imaging biomarkers to detect this tumor, which is growing rapidly in incidence. Individual HCC cells will be evaluated using scRNA-seq with trajectory analysis to identify promising earlystage targets that are highly specific for this tumor. This methodology will examine the molecular pathogenesis that drives hepatocyte transformation to identify promising imaging biomarkers that can accurately distinguish malignant from benign lesions in the context of the tumor microenvironment. Antibodies are large in dimensions, and have reduced ability to extravasate from vasculature, diffuse and penetrate into tumor, and clear from interstitial space, resulting in higher background. Peptides are much smaller in size and lower in molecular weight. The diminutive dimensions can overcome irregular microvasculature, heterogeneous uptake, and transport barriers found in HCC tumors. These protein fragments can extravasate through leaky tumor microvasculature for deeper penetration and better access to tumor targets. Peptides have less potential for immunogenicity, allowing for repeat use. Conventional ligands are being developed for specific binding to single targets only. This strategy is limited in effectiveness for heterogeneous tumor cell populations, such as HCC. Monomer peptides will be arranged in a multimer configuration to produce multivalent ligand-target interactions. Increased sensitivity occurs from simultaneous detection of multiple targets. Greater specificity arises from the multimer binding to a larger combined target epitope. Cancer targets may be detected at lower levels of expression, and at an earlier time point. Peptides specific for GPC3, CD44, and EpCAM will be used as an initial demonstration. Peptides specific for new early-stage HCC targets identified from scRNAseq will be identified and inserted. The multimer will be labeled with Gd-Dota for in vivo use to detect HCC tumors using MR imaging, and will be labeled with IRDye800 for optical imaging with laparoscopy. Cell-derived and subcutaneous tumor models do not accurately reflect the molecular and genetic profile and vascular delivery of human disease. A pre-clinical model of HCC using patient-derived tumor specimens will be implanted in an orthotopic location to validate specific multimer uptake. These tumors provide clinically relevant molecular and genetic profiles. Tumor implantation in the orthotopic location provides vascular delivery with intact stroma and vasculature that is representative of the clinical scenario. Success completion of the proposed aims will result in a peptide multimer that will be validated in an advanced pre-clinical model for early cancer detection that reflects the heterogeneity and variability of cell surface targets expressed by HCC.