Increased precision of orthotopic and metastatic breast cancer surgery guided by matrix metalloproteinase-activatable near-infrared fluorescence probes.

Chongwei Chi,Jinzuo Ye,Jiandong Wang,Qian Zhang,Yang Du,Jie Tian,Jingdan Qiu,Zhongliang Wang,Deqiang Kou,Yamin Mao

doi:10.1038/srep14197

Abstract

Advanced medical imaging technology has allowed the use of fluorescence molecular imaging-guided breast cancer surgery (FMI-guided BCS) to specifically label tumour cells and to precisely distinguish tumour margins from normal tissues intra-operatively, a major challenge in the medical field. Here, we developed a surgical navigation system for real-time FMI-guided BCS. Tumours derived from highly metastatic 4T1-luc breast cancer cells, which exhibit high expression of matrix metalloproteinase (MMP) and human epidermal growth factor receptor 2 (HER2), were established in nude mice; these mice were injected with smart MMP-targeting and “always-on” HER2-targeting near-infrared (NIR) fluorescent probes. The fluorescence signal was imaged to assess in vivo binding of the probes to the tumour and metastatic sites. Then, orthotopic and metastatic breast tumours were precisely removed under the guidance of our system. The post-operative survival rate of mice was improved by 50% with the new method. Hematoxylin and eosin staining and immunohistochemical staining for MMP2 and CD11b further confirmed the precision of tumour dissection. Our method facilitated the accurate detection and complete removal of breast cancer tumours and provided a method for defining the molecular classification of breast cancer during surgery, thereby improving prognoses and survival rates.

Highlights

About 20–50% of breast cancer patients have positive tumour margins after lumpectomy[5,6,7,8]
Recent studies have supported the use of fluorescence Molecular imaging (MI) (FMI) during surgery to overcome the challenges associated with precise intra-operative detection of tumour margins[17] due to the following advantages: (1) FMI is non-radioactive, non-invasive, highly sensitive, and specific for tumour detection, and many studies have used this technique for detection of different types of tumours[18,19,20,21,22,23]; (2) FMI is a simple, robust approach that is well suited for intra-operative imaging-guided surgery; and (3) compared with other imaging techniques, FMI-guided breast cancer surgery (BCS) can realise the detection of early lesions in vivo and has been shown to be advantageous for the intra-operative, accurate localisation of tumour margins and the precise resection of lesions[24,25]
To evaluate the function and efficacy of our FMI-guided BCS technique for the precise detection and complete resection of breast metastatic tumours, we used a smart fluorescent probe, MMPSense 750 FAST to target Matrix metalloproteinases (MMPs) based on the following three reasons: (1) the probe can efficiently and abundantly accumulate at tumour sites due to the enhanced permeability and retention effect (EPR); (2) MMP-750 is a MMP-activatable imaging agent that is optically silent upon injection and produces a fluorescent signal after cleavage by MMP enzyme; and (3) near-infrared (NIR) fluorescence, emitted at 750 nm, eliminates autofluorescence from the body, which can increase the accuracy of imaging data collected from biomedical applications

Summary

Introduction

About 20–50% of breast cancer patients have positive tumour margins after lumpectomy[5,6,7,8]. To evaluate the function and efficacy of our FMI-guided BCS technique for the precise detection and complete resection of breast metastatic tumours, we used a smart fluorescent probe, MMPSense 750 FAST (hereafter referred to as MMP-750; PerkinElmer, Inc., Waltham, MA, USA) to target MMP based on the following three reasons: (1) the probe can efficiently and abundantly accumulate at tumour sites due to the enhanced permeability and retention effect (EPR); (2) MMP-750 is a MMP-activatable imaging agent that is optically silent upon injection and produces a fluorescent signal after cleavage by MMP enzyme (with a high signal-to-background ratio); and (3) near-infrared (NIR) fluorescence, emitted at 750 nm, eliminates autofluorescence from the body, which can increase the accuracy of imaging data collected from biomedical applications. An always-on probe, HER2Sense 645 (hereafter referred to as HER2-645; PerkinElmer, Inc.), was used to positively and target HER2

Methods

Results

Conclusion