Design, Synthesis and In Vivo Fluorescence Imaging Study of a Cytochrome P450 1B1 Targeted NIR Probe Containing a Chelator Moiety

Abstract

Cytochrome P450 (CYP) 1B1 has been found to be overexpressed specifically in tumor tissues at an early stage, which makes it a potential cancer biomarker for molecular imaging. Multimodal imaging combines different imaging modalities and offers more comprehensive information. Thus, imaging probes bearing more than one kind of signal fragment have been extensively explored and display great promise. Herein, we developed a near infrared (NIR) probe with a chelator moiety targeting CYP1B1 by conjugating α‐naphthoflavone (ANF) derivatives with both an NIR dye and a chelator for potential application in bimodal imaging. Enzymatic inhibitory studies demonstrated inhibitory activity against CYP1B1 and selectivity among CYP1 were successfully retained after chemical modification. Cell‐based saturation studies indicated nanomolar range binding affinity between the probe and CYP1B1 overexpressed cancer cells. In vitro competitive binding assays monitored by confocal microscopy revealed that the probe could specifically accumulate in tumor cells. In vivo and ex vivo imaging studies demonstrated that the probe could effectively light‐up the tumor tissues as early as 2 hours post‐injection. In addition, the fluorescence was significantly blocked by co‐injection of CYP1B1 inhibitor, which indicated the probe accumulation in tumor sites was due to specific binding to CYP1B1.

The Impact of Inorganic Systems and Photoactive Metal Compounds on Cytochrome P450 Enzymes and Metabolism: From Induction to Inhibition

“…It should be noted that various organic systems have been studied with characteristics similar to these "wires". For example, organic fluorophores have been tethered to binding groups for P450 cam [66][67][68] and CYP1B1 [69], including a system with a pendant metal chelating group [70].…”

Fe3O4-Cy5.5-trastuzumab magnetic nanoparticles for magnetic resonance/near-infrared imaging targeting HER2 in breast cancer

“…Earlystage breast cancer is considered to be completely curable, and timely diagnosis and intervention are the keys to its cure [2,8,9]. The combination of molecular imaging with nanotechnology can monitor and evaluate the microscopic changes of some molecular markers at the molecular level, which solves the defects of conventional imaging methods that are easy to miss and misdiagnose [10][11][12][13][14]. This is of great significance in realizing early detection of breast cancer, timely treatment, and real-time postoperative evaluation.…”

Design and Synthesis of Novel Near-Infrared Fluorescence Probes Based on an Open Conformation of a Cytochrome P450 1B1 Complex for Molecular Imaging of Colorectal Tumors

“…The probes could indicate the tumor site in the tumor-bearing mice. 38,39 Although the derivative with high inhibitory activity was selected as the ligand, when linkers and fluorescent fragments were introduced, the inhibitory activity of the ANF derivatives against the CYP1B1 enzyme decreased by nearly 1000-fold. As the reported probes were designed based on a closed conformation of the CYP1B1 complex, we speculated that the linker and signal fragment of the probes might not extend to the real entrance of the active pocket of the CYP1B1 protein.…”

“…The binding affinity of these probes for CYP1B1 was at the nanomolar level. The probes could indicate the tumor site in the tumor-bearing mice. , …”