Integrin alpha 6 Targeted Near Infrared Fluorescent Imaging and Photoacoustic Imaging of Hepatocellular Carcinoma in Mice

Background and Aims: Hepatocellular carcinoma (HCC) is the fourth most common cause of cancer-related death and ranks sixth in terms of incident cases worldwide. The purpose of this study was to develop an effective and sen-sitive method to distinguish liver cancer tissues from nor-mal tissues in HCC patients. Integrin alpha 6 is a promising cell surface target for molecular imaging of HCC, where it is overexpressed and is a prognostic biomarker. We previous-ly identified an integrin alpha 6-targeted peptide CRWYDENAC (RWY) that has been used for positron emission tomogra-phy (PET) imaging of HCC in mouse models. Methods: We labeled the integrin alpha 6-targeted RWY peptide with cyanine 7 (Cy7) to form an optical probe (Cy7-RWY) for near infra -red fluorescent (NIRF) and photoacoustic (PA) imaging in HCC. Mice transplanted with subcutaneous HCC-LM3 or or-thotopic HCC-H22 cells that overexpressed integrin alpha 6 were intravenously injected with Cy7-RWY and its corresponding Cy7-control. NIRF and PA images of mice were collected from 0 to 48 h after injection. Results: Both NIRF and PA signals started to accumulate in the tumor 2 h after injec-tion of Cy7-RWY and peaked at 24 h. Conclusions: Cy7-RWY is a promising optical probe for NIRF and PA imaging of HCC in mice, and has potential clinical application for HCC detection.