Heptamethine carbocyanine DZ-1 dye for near-infrared fluorescence imaging of hepatocellular carcinoma

// Jiaze An 1, 2, * , Ningning Zhao 1, * , Caiqin Zhang 1 , Yong Zhao 1 , Dengxu Tan 1 , Ya Zhao 1 , Bing Bai 1 , Hai Zhang 1 , Boyang Jason Wu 3, ** and Changhong Shi 1, ** 1 Laboratory Animal Center, The Fourth Military Medical University, Xi’an, Shaanxi 710032, China 2 Department of Hepatobiliary and Pancreaticosplenic Surgery, Xijing Hospital, The Fourth Military Medical University, Xi’an, Shaanxi 710032, China 3 Department of Pharmaceutical Sciences, College of Pharmacy, Washington State University, Spokane, WA 99210, USA * These authors contributed equally to this work ** Joint corresponding authors Correspondence to: Changhong Shi, email: changhong@fmmu.edu.cn Boyang Jason Wu, email: boyang.wu@wsu.edu Keywords: heptamethine carbocyanine, hepatocellular carcinoma, HIF1α, near-infrared fluorescence, organic anion-transporting polypeptide Received: February 28, 2017      Accepted: April 17, 2017      Published: May 24, 2017 ABSTRACT Near-infrared fluorescence (NIRF) dyes have recently emerged as promising tools for non-invasive imaging of different types of cancers. Here, we explored the potential utility of a NIRF DZ-1 dye, with dual imaging and tumour targeting functions, in hepatocellular carcinoma (HCC). We showed the preferential uptake of DZ-1 by HCC cells in vitro and in derived subcutaneous/orthotopic tumour xenografts, accompanied by a minimal effect on normal cells. DZ-1 simplified tumour growth profiling as well, since we were able to correlate NIRF signals with tumour volume and/or tumour-emitting luminescence in mice. Using both orthotopic tumour transplantation and cirrhosis models in parallel, we demonstrated the ability of DZ-1 to differentiate liver tumour from cirrhosis. DZ-1 showed superiority in HCC imaging over indocyanine green by demonstrating significantly enhanced tumour-targeting specificity. At the cellular level, DZ-1 was mainly retained in mitochondria and lysosomes. Additionally, DZ-1 fluorescence spectroscopy has been used for the intraoperative navigation of rabbit liver cancer, to determine surgical margins. We showed that tumor hypoxia and select organic anion-transporting polypeptide genes mediate NIRF dye uptake in HCC, which was supported by clinical evidence. All these findings represent the first evidence that DZ-1 is an effective molecular probe for tumour-specific imaging in HCC, and provide insights into the development of a new generation of imaging agents for intraoperative guidance of cancer surgery.