Near-infrared fluorescence imaging-guided surgery improves recurrence-free survival rate in novel orthotopic animal model of head and neck squamous cell carcinoma

PET/NIR Fluorescence Bimodal Imaging for Targeted Tumor Detection

Cancer is one of the greatest threats to human health due to late diagnosis and incomplete resection. The bimodal probe combines positron emission tomography (PET) imaging for noninvasive whole-body scanning with intraoperative near-infrared fluorescence (NIRF) surgical guidance for preoperative tumor detection, tumor resection during surgery, and postoperative monitoring. We developed a new PET/NIRF bimodal imaging agent, [68Ga]Ga-DOTA-NPC, covalently coupled to DCDSTCY and DOTA via ethylenediamine and radiolabeled with gallium-68, and investigated it in vitro and in vivo. The probe was found to be preferential for colon cancer cells due to the organic anion-transporting polypeptide1B3 (OATP1B3). PET/NIRF imaging allowed us to confirm [68Ga]Ga-DOTA-NPC as a promising probe for tumor detection, as it provides good biosafety and high-contrast tumor accumulation. Orthotopic and subcutaneous colon tumors were successfully resected under real-time NIRF guidance. [68Ga]Ga-DOTA-NPC provides highly sensitive and unlimited tissue-penetrating PET/NIRF imaging, helping to visualize and differentiate tumors from adjacent tissue.

Stimuli-Responsive Polymer Nanoprobes Intended for Fluorescence-Guided Surgery of Malignant Head-and-Neck Tumors and Metastases

Nano-sized carriers are widely studied as suitable candidates for the advanced delivery of various bioactive molecules such as drugs and diagnostics. Herein, the development of long-circulating stimuli-responsive polymer nanoprobes tailored for the fluorescently-guided surgery of solid tumors is reported. Nanoprobes are designed as long-circulating nanosystems preferably accumulated in solid tumors due to the Enhanced permeability and retention effect, so they act as a tumor microenvironment-sensitive activatable diagnostic. This study designs polymer probes differing in the structure of the spacer between the polymer carrier and Cy7 by employing pH-sensitive spacers, oligopeptide spacers susceptible to cathepsin B-catalyzed enzymatic hydrolysis, and non-degradable control spacer. Increased accumulation of the nanoprobes in the tumor tissue coupled with stimuli-sensitive release behavior and subsequent activation of the fluorescent signal upon dye release facilitated favorable tumor-to-background ratio, a key feature for fluorescence-guided surgery. The probes show excellent diagnostic potential for the surgical removal of intraperitoneal metastasis and orthotopic head and neck tumors with very high efficacy and accuracy. In addition, the combination of macroscopic resection followed by fluorescence-guided surgery using developed probes enable the identification and resection of most of the CAL33 intraperitoneal metastases with total tumor burden reduced to 97.2%.

Free three-dimensional image software in local extension assessment of oral squamous cell carcinoma: a pilot study

OBJECTIVE

Oral Squamous Cell Carcinoma (OSCC) is conventionally treated by surgical resection, and positive surgical margins strongly increase local recurrence and decrease survival. This study aimed to evaluate whether a Three-Dimensional Segmentation (3DS) image of OSCC confers advantage over Multiplanar Reconstruction (MPR) of OSCC using images of computed tomography scan in surgical planning of tumor resection.

METHODS

Twenty-six patients with locally advanced OSCC had tumor morphology and dimensions evaluated by MPR images, 3DS images, and Surgical Pathology Specimen (SPS) analyses (gold standard). OSCC resection was performed with curative intent using only MPR images.

RESULTS

OSCC morphology was more accurately assessed by 3DS than by MPR images. Similar OSCC volumes and dimensions were obtained when MPR images, 3DS images and SPS measurements were considered. Nevertheless, there was a strong correlation between the OSCC longest axis measured by 3DS and SPS analyses (ICC = 0.82; 95% CI 0.59‒0.92), whereas only a moderate correlation was observed between the longest axis of OSCC measured by MPR images and SPS analyses (ICC = 0.51; 95% CI 0.09‒0.78). Taking only SPS with positive margins into account, MPR images and 3DS images underestimated the tumor's longest axis in eight out of 11 (72.7%) and 5 out of the 11 (45.5%) cases, respectively.

CONCLUSION

Our data present preliminary evidence that 3DS model represents a useful tool for surgical planning of OSCC resection, but confirmation in a larger cohort of patients is required.

LEVEL OF EVIDENCE

Laboratory study.

Prognostic Value of Urokinase-Type Plasminogen Activator Receptor PET/CT in Head and Neck Squamous Cell Carcinomas and Comparison with 18F-FDG PET/CT: A Single-Center Prospective Study

The aim of this phase II clinical trial (NCT02965001) was to evaluate the prognostic value of urokinase-type plasminogen activator receptor (uPAR) PET/CT with the novel ligand ⁶⁸Ga-NOTA-AE105 in head and neck cancer and compare it with ¹⁸F-FDG. Methods: Patients with head and neck squamous cell carcinoma referred for curatively intended radiotherapy were eligible and prospectively included in this study. ⁶⁸Ga-uPAR and ¹⁸F-FDG PET/CT were performed before initiation of curatively intended radiotherapy, and the SUV_max of the primary tumor was measured on both PET/CT studies by 2 independent readers. Relapse-free survival (RFS) and overall survival (OS) were calculated, and optimal cutoffs were established for ⁶⁸Ga-uPAR and ¹⁸F-FDG PET independently and compared using log rank and Kaplan-Meier statistics, as well as univariate and multivariate analysis in a Cox proportional-hazards model. Results: In total, 57 patients were included and followed for a median of 33.8 mo (range, 2.30-47.2, mo). The median SUV_max of the primary tumors was 2.98 (range, 1.94-5.24) for ⁶⁸Ga-uPAR and 15.7 (range, 4.24-45.5) for ¹⁸F-FDG. The optimal cutoffs for ⁶⁸Ga-NOTA-AE105 SUV_max in the primary tumor were 2.63 for RFS and 2.66 for OS. A high uptake of ⁶⁸Ga-NOTA-AE105 (SUV_max above cutoff) was significantly associated with poor RFS and OS (log-rank P = 0.012 and P = 0.022). ⁶⁸Ga-NOTA-AE105 uptake in the primary tumor was significantly associated with poor RFS in univariate analysis (hazard ratio [HR], 8.53 [95% CI, 1.12-64.7]; P = 0.038), and borderline-associated with OS (HR, 7.44 [95% CI, 0.98-56.4]; P = 0.052). For ¹⁸F-FDG PET, the optimal cutoffs were 22.7 for RFS and 22.9 for OS. An ¹⁸F-FDG SUV_max above the cutoff was significantly associated with reduced RFS (log-rank P = 0.012) and OS (log-rank P = 0.000). ¹⁸F-FDG uptake was significantly associated with reduced RFS (HR, 3.27 [95% CI, 1.237-8.66]; P = 0.017) and OS (HR, 7.10 [95% CI, 2.60-19.4]; P < 0.001) in univariate analysis. In a multivariate analysis including ⁶⁸Ga-uPAR SUV_max, ¹⁸F-FDG SUV_max, TNM stage, and p16 status, only ⁶⁸Ga-uPAR SUV_max remained significant (HR, 8.51 [95% CI, 1.08-66.9]; P = 0.042) for RFS. For OS, only TNM stage and ¹⁸F-FDG remained significant. Conclusion: The current trial showed promising results for the use of ⁶⁸Ga-uPAR PET SUV_max in the primary tumor to predict RFS in head and neck squamous cell carcinoma patients referred for curatively intended radiotherapy when compared with ¹⁸F-FDG PET, TNM stage, and p16 status. ⁶⁸Ga-uPAR PET could potentially become valuable for identification of patients suited for deescalation of treatment and risk-stratified follow-up schemes.

Near-infrared fluorescence guided surgery: State of the evidence from a health technology assessment perspective

Different applications of near-infrared fluorescence-guided surgery are very promising, and techniques that help surgeons in intraoperative guidance have been developed, thereby bridging the gap between preoperative imaging and intraoperative visualization and palpation. Thus, these techniques are advantageous in terms of being faster, safer, less invasive, and cheaper. There are a few fluorescent dyes available, but the most commonly used dye is indocyanine green. It can be used in its natural form, but different nanocapsulated and targeted modifications are possible, making this dye more stable and specific. A new active tumor-targeting strategy is the conjugation of indocyanine green nanoparticles with antibodies, making this dye targeted and highly selective to various tumor proteins. In this mini-review, we discuss the application of near-infrared fluorescence-guided techniques in thoracic surgery. During lung surgery, it can help find small, non-palpable, or additional tumor nodules, it is also useful for finding the sentinel lymph node and identifying the proper intersegmental plane for segmentectomies. Furthermore, it can help visualize the thoracic duct, smaller bullae of the lung, phrenic nerve, or pleural nodules. We summarize current applications and provide a framework for future applications and development.

Towards Photodynamic Image-Guided Surgery of Head and Neck Tumors: Photodynamic Priming Improves Delivery and Diagnostic Accuracy of Cetuximab-IRDye800CW

Fluorescence image-guided surgery (IGS) using antibody conjugates of the fluorophore IRDye800CW have revolutionized the surgical debulking of tumors. Cetuximab, an anti-epidermal growth factor receptor (EGFR) monoclonal antibody, conjugated to IRDye800CW (Cet-IRDye800) is the first molecular targeted antibody probe to be used for IGS in head and neck cancer patients. In addition to surgical debulking, Cetuximab-targeted photodynamic therapy (photoimmunotherapy; PIT) is emerging in the clinic as a powerful modality for head and neck tumor photodestruction. A plethora of other photoactivable agents are also in clinical trials for photodynamic-based therapies of head and neck cancer. Considering the vascular and stromal modulating effects of sub-therapeutic photodynamic therapy, namely photodynamic priming (PDP), this study explores the potential synergy between PDP and IGS for a novel photodynamic image-guided surgery (P-IGS) strategy. To the best of our knowledge, this is the first demonstration that PDP of the tumor microenvironment can augment the tumor delivery of full-length antibodies, namely Cet-IRDye800. In this study, we demonstrate a proof-of-concept that PDP primes orthotopic FaDu human head and neck tumors in mice for P-IGS by increasing the delivery of Cet-IRDye800 by up to 138.6%, by expediting its interstitial accumulation by 10.5-fold, and by increasing its fractional tumor coverage by 49.5% at 1 h following Cet-IRDye800 administration. Importantly, PDP improves the diagnostic accuracy of tumor detection by up to 264.2% with respect to vicinal salivary glands at 1 h. As such, PDP provides a time-to-surgery benefit by reducing the time to plateau 10-fold from 25.7 h to 2.5 h. We therefore propose that a pre-operative PDP regimen can expedite and augment the accuracy of IGS-mediated surgical debulking of head and neck tumors and reduce the time-to-IGS. Furthermore, this P-IGS regimen, can also enable a forward-looking post-operative protocol for the photodestruction of unresectable microscopic disease in the surgical bed. Beyond this scope, the role of PDP in the homogenous delivery of diagnostic, theranostic and therapeutic antibodies in solid tumors is of considerable significance to the wider community.

Tumor-Specific Imaging with Angiostamp800 or Bevacizumab-IRDye 800CW Improves Fluorescence-Guided Surgery over Indocyanine Green in Peritoneal Carcinomatosis

Complete surgical removal of lesions improves survival of peritoneal carcinomatosis and can be enhanced by intraoperative near-infrared fluorescence imaging. Indocyanine green (ICG) is the only near-infrared fluorescent dye approved for clinical use, but it lacks specificity for tumor cells, highlighting the need for tumor-selective targeting agents. We compared the tumor-specific near-infrared fluorescent probes Bevacizumab-IRDye 800CW and Angiostamp800, which target tumor angiogenesis and cancer cells, to ICG for fluorescence-guided surgery in peritoneal carcinomatosis of ovarian origin. The probes were administered to mice with orthotopic peritoneal carcinomatosis prior to conventional and fluorescence-guided surgery. The influence of neoadjuvant chemotherapy was also assessed. Conventional surgery removed 88.0 ± 1.2% of the total tumor load in mice. Fluorescence-guided surgery allowed the resection of additional nodules, enhancing the total tumor burden resection by 9.8 ± 0.7%, 8.5 ± 0.8%, and 3.9 ± 1.2% with Angiostamp800, Bevacizumab-IRDye 800CW and ICG, respectively. Interestingly, among the resected nodules, 15% were false-positive with ICG, compared to only 1.4% with Angiostamp800 and 3.5% with Bevacizumab-IRDye 800CW. Furthermore, conventional surgery removed only 69.0 ± 3.9% of the total tumor burden after neoadjuvant chemotherapy. Fluorescence-guided surgery with Angiostamp800 and Bevacizumab-IRDye 800CW increased the total tumor burden resection to 88.7 ± 4.3%, whereas ICG did not improve surgery at all. Bevacizumab-IRDye 800CW and Angiostamp800 better detect ovarian tumors and metastases than the clinically used fluorescent tracer ICG, and can help surgeons completely remove tumors, especially after surgery neoadjuvant chemotherapy.

Gold Nanoclusters: Imaging, Therapy, and Theranostic Roles in Biomedical Applications

For the past two decades, atomic gold nanoclusters (AuNCs, ultrasmall clusters of several to 100 gold atoms, having a total diameter of <2 nm) have emerged as promising agents in the diagnosis and treatment of cancer. Owing to their small size, significant quantization occurs to their conduction band, which leads to emergent photonic properties and the disappearance of the plasmonic responses observed in larger gold nanoparticles. For example, AuNCs exhibit native luminescent properties, which have been well-explored in the literature. Using proteins, peptides, or other biomolecules as structural scaffolds or capping ligands, required for the stabilization of AuNCs, improves their biocompatibility, while retaining their distinct optical properties. This paved the way for the use of AuNCs in fluorescent bioimaging, which later developed into multimodal imaging combined with computer tomography and magnetic resonance imaging as examples. The development of AuNC-based systems for diagnostic applications in cancer treatment was then made possible by employing active or passive tumor targeting strategies. Finally, the potential therapeutic applications of AuNCs are extensive, having been used as light-activated and radiotherapy agents, as well as nanocarriers for chemotherapeutic drugs, which can be bound to the capping ligand or directly to the AuNCs via different mechanisms. In this review, we present an overview of the diverse biomedical applications of AuNCs in terms of cancer imaging, therapy, and combinations thereof, as well as highlighting some additional applications relevant to biomedical research.

Modular Synthesis of Peptide-Based Single- and Multimodal Targeted Molecular Imaging Agents

A practical, modular synthesis of targeted molecular imaging agents (TMIAs) containing near-infrared dyes for optical molecular imaging (OMI) or chelated metals for magnetic resonance imaging (MRI) and single-photon emission correlation tomography (SPECT) or positron emission tomography (PET) has been developed. In the method, imaging modules are formed early in the synthesis by attaching imaging agents to the side chain of protected lysines. These modules may be assembled to provide a given set of single- or dual-modal imaging agents, which may be conjugated in the last steps of the synthesis under mild conditions to linkers and targeting groups. A key discovery was the ability of a metal such as gadolinium, useful in MRI, to serve as a protecting group for the chelator, 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA). It was further discovered that two lanthanide metals, La and Ce, can double as protecting groups and placeholder metals, which may be transmetalated under mild conditions by metals used for PET in the final step. The modular method enabled the synthesis of discrete targeted probes with two of the same or different dyes, two same or different metals, or mixtures of dyes and metals. The approach was exemplified by the synthesis of single- or dual-modal imaging modules for MRI-OMI, PET-OMI, and PET-MRI, followed by conjugation to the integrin-seeking peptide, c(RGDyK). For Gd modules, their efficacy for MRI was verified by measuring the NMR spin-lattice relaxivity. To validate functional imaging of TMIAs, dual-modal agents containing Cy5.5 were shown to target A549 cancer cells by confocal fluorescence microscopy.

Targeted molecular imaging of head and neck squamous cell carcinoma: a window into precision medicine

Tumor biomarkers play important roles in tumor growth, invasion, and metastasis. Imaging of specific biomarkers will help to understand different biological activities, thereby achieving precise medicine for each head and neck squamous cell carcinoma (HNSCC) patient. Here, we describe various molecular targets and molecular imaging modalities for HNSCC imaging. An extensive search was undertaken in the PubMed database with the keywords including “HNSCC,” “molecular imaging,” “biomarker,” and “multimodal imaging.” Imaging targets in HNSCC consist of the epidermal growth factor receptor, cluster of differentiation 44 variant 6 (CD44v6), and mesenchymal-epithelial transition factor and integrins. Targeted molecular imaging modalities in HNSCC include optical imaging, ultrasound, magnetic resonance imaging, positron emission tomography, and single-photon emission computed tomography. Making the most of each single imaging method, targeted multimodal imaging has a great potential in the accurate diagnosis and therapy of HNSCC. By visualizing tumor biomarkers at cellular and molecular levels in vivo, targeted molecular imaging can be used to identify specific genetic and metabolic aberrations, thereby accelerating personalized treatment development for HNSCC patients.

Validation of a Three-Dimensional Head and Neck Spheroid Model to Evaluate Cameras for NIR Fluorescence-Guided Cancer Surgery

Near-infrared (NIR) fluorescence-guided surgery is an innovative technique for the real-time visualization of resection margins. The aim of this study was to develop a head and neck multicellular tumor spheroid model and to explore the possibilities offered by it for the evaluation of cameras for NIR fluorescence-guided surgery protocols. FaDu spheroids were incubated with indocyanine green (ICG) and then included in a tissue-like phantom. To assess the capability of Fluobeam® NIR camera to detect ICG in tissues, FaDu spheroids exposed to ICG were embedded in 2, 5 or 8 mm of tissue-like phantom. The fluorescence signal was significantly higher between 2, 5 and 8 mm of depth for spheroids treated with more than 5 µg/mL ICG (p < 0.05). The fluorescence intensity positively correlated with the size of spheroids (p < 0.01), while the correlation with depth in the tissue-like phantom was strongly negative (p < 0.001). This multicellular spheroid model embedded in a tissue-like phantom seems to be a simple and reproducible in vitro tumor model, allowing a comparison of NIR cameras. The ideal configuration seems to be 450 μm FaDu spheroids incubated for 24 h with 0.05 mg/mL of ICG, ensuring the best stability, toxicity, incorporation and signal intensity.

Aza-BODIPY: A New Vector for Enhanced Theranostic Boron Neutron Capture Therapy Applications

Boron neutron capture therapy (BNCT) is a radiotherapeutic modality based on the nuclear capture of slow neutrons by stable ¹⁰B atoms followed by charged particle emission that inducing extensive damage on a very localized level (<10 μm). To be efficient, a sufficient amount of ¹⁰B should accumulate in the tumor area while being almost cleared from the normal surroundings. A water-soluble aza-boron-dipyrromethene dyes (BODIPY) fluorophore was reported to strongly accumulate in the tumor area with high and BNCT compatible Tumor/Healthy Tissue ratios. The clinically used ¹⁰B-BSH (sodium borocaptate) was coupled to the water-soluble aza-BODIPY platform for enhanced ¹⁰B-BSH tumor vectorization. We demonstrated a strong uptake of the compound in tumor cells and determined its biodistribution in mice-bearing tumors. A model of chorioallantoic membrane-bearing glioblastoma xenograft was developed to evidence the BNCT potential of such compound, by subjecting it to slow neutrons. We demonstrated the tumor accumulation of the compound in real-time using optical imaging and ex vivo using elemental imaging based on laser-induced breakdown spectroscopy. The tumor growth was significantly reduced as compared to BNCT with ¹⁰B-BSH. Altogether, the fluorescent aza-BODIPY/¹⁰B-BSH compound is able to vectorize and image the ¹⁰B-BSH in the tumor area, increasing its theranostic potential for efficient approach of BNCT.

Real-time surveillance of surgical margins via ICG-based near-infrared fluorescence imaging in patients with OSCC

Background

Local recurrence is the main cause of death among patients with oral squamous cell carcinoma (OSCC). This study assessed near-infrared fluorescence (NIF) imaging and spectroscopy to monitor surgical margins intraoperatively for OSCC.

Methods

Cytological and animal experiments were first performed to confirm the feasibility of monitoring surgical margins with NIF imaging and spectroscopy. Then, 20 patients with OSCC were included in the clinical trials. At 6–8 h after 0.75 mg/kg indocyanine green (ICG) injection, all patients underwent surgery with NIF imaging. During the surgery, both NIF images and quantified fluorescence intensity were acquired to monitor the surgical margins.

Results

In cytological and animal experiments, the results showed it was feasible to monitor surgical margins with NIF imaging and spectroscopy. Fluorescence was detected in primary tumors in all patients. The fluorescence intensities of the tumor, peritumoral, and normal tissues were 398.863 ± 151.47, 278.52 ± 84.89, and 274.5 ± 100.93 arbitrary units (AUs), respectively (P < 0.05). The SBR of tumor to peritumoral tissue and normal tissues was computed to be 1.45 ± 0.36 and 1.56 ± 0.41, respectively. After primary tumor excision, the wounds showed abnormal fluorescence in four patients (4/20), and residual cancer cells were confirmed by pathological examination in two patients (2/20).

Conclusion

These findings confirmed the complementary value of NIF imaging during radical tumor resection of OSCC. Before tumor resection, we could utilize the fluorescence margin produced by ICG NIF imaging to determine the surgical margin. Moreover, after tumor blocks were removed, the status of surgical margin could also be evaluated rapidly by ICG NIF imaging of tumor bed and in vitro specimens.

Noninvasive monitoring of liver metastasis development via combined multispectral photoacoustic imaging and fluorescence diffuse optical tomography

Rationale:In vivo molecular imaging in preclinical animal models is a tool of choice for understanding the pathophysiological mechanisms involved in cancer development and for conducting drug development research. Moreover, combining several imaging modalities can provide multifaceted, complementary and cross-validated information. Photoacoustic imaging (PAI) is a promising imaging modality that can reflect blood vasculature and tissue oxygenation as well as detect exogenous molecules, but one shortcoming of PAI is a lack of organic photoacoustic contrast agents capable of providing tumor contrast.

Methods: In the present study, we designed an animal model of liver metastases from colon cancer and monitored metastasis development by in vivo bioluminescence and X-ray microcomputed tomography. Contrast-agent-free PAI was used to detect the respective amounts of oxy- and deoxyhemoglobin and, thus, liver tissue oxygenation. two contrast agents, Angiostamp800 and indocyanin green (ICG), respectively with and without tumor targeting specificity, were then evaluated for their dual fluorescence and photoacoustic detectability and were then used for combined PAI and fluorescence diffuse optical tomography (fDOT) at various disease development stages.

Findings: Contrast-agent-free PAI reflected tumor angiogenesis and gradual hypoxia during metastasis development. Multispectral PAI enabled noninvasive real-time monitoring of ICG blood pharmacokinetics, which demonstrated tumor-related liver dysfunction. Both PAI and fluorescence ICG signals were clearly modified in metastasis-bearing livers but did not allow for differentiation between different disease stages. In contrast, there was a significant improvement achieved by using the tumor-specific marker Angiostamp800, which provided gradually increasing PAI and fDOT signals during metastasis development.

Conclusion: We demonstrated for the first time the value of using Angiostamp800 as a bimodal tumor-targeting contrast agent for combined PAI and fluorescence imaging of liver metastasis progression in vivo.

NIR fluorescence-guided tumor surgery: new strategies for the use of indocyanine green

Surgery is the frontline treatment for a large number of cancers. The objective of these excisional surgeries is the complete removal of the primary tumor with sufficient safety margins. Removal of the entire tumor is essential to improve the chances of a full recovery. To help surgeons achieve this objective, near-infrared fluorescence-guided surgical techniques are of great interest. The concomitant use of fluorescence and indocyanine green (ICG) has proved effective in the identification and characterization of tumors. Moreover, ICG is authorized by the Food and Drug Administration and the European Medicines Agency and is therefore the subject of a large number of studies. ICG is one of the most commonly used fluorophores in near-infrared fluorescence-guided techniques. However, it also has some disadvantages, such as limited photostability, a moderate fluorescence quantum yield, a high plasma protein binding rate, and undesired aggregation in aqueous solution. In addition, ICG does not specifically target tumor cells. One way to exploit the capabilities of ICG while offsetting these drawbacks is to develop high-performance near-infrared nanocomplexes formulated with ICG (with high selectivity for tumors, high tumor-to-background ratios, and minimal toxicity). In this review article, we focus on recent developments in ICG complexation strategies to improve near-infrared fluorescence-guided tumor surgery. We describe targeted and nontargeted ICG nanoparticle models and ICG complexation with targeting agents.

Novel Peptide NIRF Optical Surgical Navigation Agents for HNSCC

Head and neck squamous cell carcinoma (HNSCC) survival rates have not improved in a decade, with a 63% 5-year recurrence rate after surgery, making HNSCC a compelling indication for optical surgical navigation (OSN). A promising peptide, HN1, targeted and internalized in human HNSCC cells in multiple laboratories, but was slow (24 h) to accumulate. We modified HN1 and explored structural variables to improve the uptake kinetics and create IRdye800 adducts useful for OSN. Eleven new molecules were synthesized and characterized chemically, in human HNSCC cells (Cal 27), and in HNSCC xenograft mice. Cal 27 flank xenografts in Balb/c nude mice were imaged for 3-48 h after 40 nmol intravenous doses of IR800-labeled molecules. Cell uptake kinetics in the 1-2 h window incubated at 1-10 μM were independent of the dye label (FITC, Cy5, or IR800), but increased markedly with additional N-terminal lipophilic substitution, and after resequencing the peptide to separate polar amino acids and move the lysine-dye more centrally. Microscopy confirmed the strong Cal 27 cell binding and demonstrated primarily cytosolic and membrane localization of the fastest peptide, 4Iphf-HN17. 4Iph-HN17-IR800 showed 26-fold greater rate of uptake in cells than HN1-IR800, and far stronger OSN imaging intensity and tumor to background contrast in mice, suggesting that the new peptide is a promising candidate for OSN of HNSCC.

Gold nanoclusters as a contrast agent for image-guided surgery of head and neck tumors

With the objective to evaluate the potential of ultra-small gold (Au) nanoclusters (NCs) for optical image-guided surgery, we synthesized and characterized AuNCs shelled by zwitterionic or pegylated ligands. The toxicity of the different AuNCs was evaluated on the Head and Neck Squamous Cell Carcinoma (HNSCC) CAL-33 and SQ20B cell lines in vitro. The safer AuNCs were administrated intravenously to mice for the determination of the pharmacokinetic properties. Biodistributions were performed on orthotopic CAL-33 HNSCC-bearing mice. Finally, the AuNCs were used for image-guided surgery, allowing the increase of the survival time vs. control animals, and the number of animals without any local recurrence.

A Novel Multimodal NIR-II Nanoprobe for the Detection of Metastatic Lymph Nodes and Targeting Chemo-Photothermal Therapy in Oral Squamous Cell Carcinoma

Current surgical treatment for oral squamous cell carcinoma (OSCC) must be as precise as possible to fully resect tumors and preserve functional tissues. Thus, it is urgent to develop efficient fluorescent probes to clearly identify tumor delineation, as well as metastatic lymph nodes. Chemo-photothermal therapy combination attracted a growing attention to increase anti-tumor effect in various types of cancer, including OSCC. In the present study, we designed a multimodal NIR-II probe that involves combining photothermal therapy with chemotherapy, imaging OSCC tumors and detecting metastatic lymph nodes. Methods: In this study, we synthesized a novel near infrared (NIR)-II probe named TQTPA [4,4'-((6,7-bis(4-(hexyloxy)phenyl)-[1,2,5]thiadiazolo [3,4-g]quinoxaline-4,9-diyl)bis(thiophene-5,2-diyl))bis(N,N-diphenylaniline)] via the Suzuki reaction and prepared multimodal nanoparticles (NPs) loading TQTPA and cis-dichlorodiammine platinum (CDDP) (HT@CDDP) by hyaluronic acid. The characteristics of the NPs, including their photothermal and imaging capabilities were investigated in vitro and in vivo. Their anti-tumor efficacy was evaluated using orthotopic, tongue tumor-bearing, nude mice. Results: The NPs possessed good stability and water solubility and were pH/hyaluronidase sensitive. The good tissue penetration quality and active targeting ability enabled the NPs to draw the outline of orthotopic tongue tumors and metastatic lymph nodes as small as 1 mm in nude mice by IR-808 under NIR exposure. In vitro and in vivo experiments validated the biocompatibility and low systematic toxicity of the NPs. At the same time, the NPs acted as multimodal therapy agents, combining photothermal therapy with chemotherapy. Conclusion: With a good imaging capability and anti-tumor efficacy, our NPs successfully outlined orthotopic tongue tumors and metastatic lymph nodes as well as enabled chemo-photothermal therapy combination. Our study established a solid foundation for the application of new clinical diagnosis and treatment patterns in the future.

Evaluation of the theranostic properties of gadolinium-based nanoparticles for head and neck cancer

BACKGROUND

The aim of the study was to evaluate the benefits of the combination of Gadolinium-based nanoparticles AGuIX and radiotherapy on the recurrence free survival after tumor resection in a head and neck animal orthotopic model.

METHODS

Human head and neck CAL33 orthotopic tumors were implanted in female NMRI nude mice. The biodistribution of AGuIX was studied by fluorescence imaging. Tumor resection was performed 19 days after tumor implantation. Radiotherapy was performed 23 days after resection (10 Gy), 1 hour after AGuIX IV injection.

RESULTS

After systemic administration, AGuIX passively accumulated in the orthotopic tumors. After tumor surgery, the combination of AGuIX with radiotherapy significantly improved the recurrence free survival and the median survival time (196 days) compared to irradiated only mice (75 days).

CONCLUSION

This study demonstrated the improvement of the recurrence free survival following combination of AGuIX injection with radiotherapy after Head and neck tumor resection.

In-vivo optical imaging in head and neck oncology: basic principles, clinical applications and future directions

Head and neck cancers become a severe threat to human's health nowadays and represent the sixth most common cancer worldwide. Surgery remains the first-line choice for head and neck cancer patients. Limited resectable tissue mass and complicated anatomy structures in the head and neck region put the surgeons in a dilemma between the extensive resection and a better quality of life for the patients. Early diagnosis and treatment of the pre-malignancies, as well as real-time in vivo detection of surgical margins during en bloc resection, could be leveraged to minimize the resection of normal tissues. With the understanding of the head and neck oncology, recent advances in optical hardware and reagents have provided unique opportunities for real-time pre-malignancies and cancer imaging in the clinic or operating room. Optical imaging in the head and neck has been reported using autofluorescence imaging, targeted fluorescence imaging, high-resolution microendoscopy, narrow band imaging and the Raman spectroscopy. In this study, we reviewed the basic theories and clinical applications of optical imaging for the diagnosis and treatment in the field of head and neck oncology with the goal of identifying limitations and facilitating future advancements in the field.

Trends in Surgical Research in Head and Neck Cancer

OPINION STATEMENT

The task of surgical research is to improve the efficacy of available surgical therapeutic modalities, develop new ones, and balance this well with favorable functional outcome. Therefore, surgical research is composed of a translational and a clinical component. In translational surgical research, animal models are used to better understand the biology of head and neck cancers, but even more importantly, the biology of changes to the disease and the microenvironment created by surgical interventions. Animal models additionally allow for the development of image-guided surgery systems, novel strategies of intraoperative adjuvant treatment, and patient "avatars" to test innovative anticancer drug combinations. In clinical surgical research, surgical techniques are validated in clinical trials for effectiveness of tumor control and improvement of functional recovery of the patient. In conclusion, surgical research for head and neck cancer is an active field spanning across the entire breadth of basic and clinical science devoted to a better understanding of what surgery does to the disease and to the patient.

uPAR-targeted optical near-infrared (NIR) fluorescence imaging and PET for image-guided surgery in head and neck cancer: proof-of-concept in orthotopic xenograft model

Purpose

Urokinase-like Plasminogen Activator Receptor (uPAR) is overexpressed in a variety of carcinoma types, and therefore represents an attractive imaging target. The aim of this study was to assess the feasibility of two uPAR-targeted probes for PET and fluorescence tumor imaging in a human xenograft tongue cancer model.

Experimental design and results

Tumor growth of tongue cancer was monitored by bioluminescence imaging (BLI) and MRI. Either ICG-Glu-Glu-AE105 (fluorescent agent) or ⁶⁴Cu-DOTA-AE105 (PET agent) was injected systemically, and fluorescence imaging or PET/CT imaging was performed. Tissue was collected for micro-fluorescence imaging and histology. A clear fluorescent signal was detected in the primary tumor with a mean in vivo tumor-to-background ratio of 2.5. Real-time fluorescence-guided tumor resection was possible, and sub-millimeter tumor deposits could be localized. Histological analysis showed co-localization of the fluorescent signal, uPAR expression and tumor deposits. In addition, the feasibility of uPAR-guided robotic cancer surgery was demonstrated. Also, uPAR-PET imaging showed a clear and localized signal in the tongue tumors.

Conclusions

This study demonstrated the feasibility of combining two uPAR-targeted probes in a preclinical head and neck cancer model. The PET modality provided preoperative non-invasive tumor imaging and the optical modality allowed for real-time fluorescence-guided tumor detection and resection. Clinical translation of this platform seems promising.

Urokinase-type plasminogen activator receptor (uPAR), tissue factor (TF) and epidermal growth factor receptor (EGFR): tumor expression patterns and prognostic value in oral cancer

Background

Tumor-specific biomarkers are a prerequisite for the development of targeted imaging and therapy in oral squamous cell carcinoma (OSCC). urokinase-type Plasminogen Activator Receptor (uPAR), Tissue Factor (TF) and Epidermal Growth Factor Receptor (EGFR) are three biomarkers that exhibit enhanced expression in many types of cancers, and have been investigated as potential biomarkers for targeted strategies and prognostication. The aim of the study was to investigate the expression patterns of uPAR, TF and EGFR and their potential prognostic value in OSCC.

Methods

Immunohistochemical expression of uPAR, TF and EGFR in tumor resection specimens from 191 patients with primary OSCC was analyzed. Overall (OS) and disease-free survival (DFS) was calculated. Associations between biomarker expression, clinicopathological factors and patient survival was analyzed using the Cox proportional hazards model for univariate and multivariate analysis, log rank and Kaplan-Meier statistics.

Results

uPAR and TF exhibited a highly tumor-specific expression pattern while EGFR also showed expression in normal tissues outside the tumor compartment. The overall positive expression rate of uPAR, TF and EGFR was 95%, 58% and 98%, respectively. High uPAR expression across the entire cohort was negatively associated with OS (p = 0.031, HR = 1.595 (95%CI 1.044–2.439)) in univariate analysis. The 5-year OS for high and low uPAR expression was 39% and 56%, respectively. The expression of TF and EGFR was not associated with survival outcome.

Conclusions

This study may suggest that uPAR and TF could potentially be attractive targets for molecular imaging and therapy in OSCC due to high positive expression rates and tumor-specific expression patterns. High uPAR expression was significantly associated with a reduced survival. uPAR seems to be a prognostic biomarker in oral cancer.

RGD-Binding Integrins in Head and Neck Cancers

Alterations in integrin expression and function promote tumour growth, invasion, metastasis and neoangiogenesis. Head and neck cancers are highly vascular tumours with a tendency to metastasise. They express a wide range of integrin receptors. Expression of the αv and β1 subunits has been explored relatively extensively and linked to tumour progression and metastasis. Individual receptors αvβ3 and αvβ5 have proved popular targets for diagnostic and therapeutic agents but lesser studied receptors, such as αvβ6, αvβ8, and β1 subfamily members, also show promise. This review presents the current knowledge of integrin expression and function in squamous cell carcinoma of the head and neck (HNSCC), with a particular focus on the arginine-glycine-aspartate (RGD)-binding integrins, in order to highlight the potential of integrins as targets for personalised tumour-specific identification and therapy.

The critical role of the ZNF217 oncogene in promoting breast cancer metastasis to the bone

Bone metastasis affects >70% of patients with advanced breast cancer. However, the molecular mechanisms underlying this process remain unclear. On the basis of analysis of clinical datasets, and in vitro and in vivo experiments, we report that the ZNF217 oncogene is a crucial mediator and indicator of bone metastasis. Patients with high ZNF217 mRNA expression levels in primary breast tumours had a higher risk of developing bone metastases. MDA-MB-231 breast cancer cells stably transfected with ZNF217 (MDA-MB-231-ZNF217) showed the dysregulated expression of a set of genes with bone-homing and metastasis characteristics, which overlapped with two previously described 'osteolytic bone metastasis' gene signatures, while also highlighting the bone morphogenetic protein (BMP) pathway. The latter was activated in MDA-MB-231-ZNF217 cells, and its silencing by inhibitors (Noggin and LDN-193189) was sufficient to rescue ZNF217-dependent cell migration, invasion or chemotaxis towards the bone environment. Finally, by using non-invasive multimodal in vivo imaging, we found that ZNF217 increases the metastatic growth rate in the bone and accelerates the development of severe osteolytic lesions. Altogether, the findings of this study highlight ZNF217 as an indicator of the emergence of breast cancer bone metastasis; future therapies targeting ZNF217 and/or the BMP signalling pathway may be beneficial by preventing the development of bone metastases. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Peptide-Based Optical uPAR Imaging for Surgery: In Vivo Testing of ICG-Glu-Glu-AE105

Near infrared intra-operative optical imaging is an emerging technique with clear implications for improved cancer surgery by enabling a more distinct delineation of the tumor margins during resection. This modality has the potential to increase the number of patients having a curative radical tumor resection. In the present study, a new uPAR-targeted fluorescent probe was developed and the in vivo applicability was evaluated in a human xenograft mouse model. Most human carcinomas express high level of uPAR in the tumor-stromal interface of invasive lesions and uPAR is therefore considered an ideal target for intra-operative imaging. Conjugation of the flourophor indocyanine green (ICG) to the uPAR agonist (AE105) provides an optical imaging ligand with sufficiently high receptor affinity to allow for a specific receptor targeting in vivo. For in vivo testing, human glioblastoma xenograft mice were subjected to optical imaging after i.v. injection of ICG-AE105, which provided an optimal contrast in the time window 6–24 h post injection. Specificity of the uPAR-targeting probe ICG-AE105 was demonstrated in vivo by 1) no uptake of unconjugated ICG after 15 hours, 2) inhibition of ICG-AE105 tumor uptake by a bolus injection of the natural uPAR ligand pro-uPA, and finally 3) the histological colocalization of ICG-AE105 fluorescence and immunohistochemical detected human uPAR on resected tumor slides. Taken together, our data supports the potential use of this probe for intra-operative optical guidance in cancer surgery to ensure complete removal of tumors while preserving adjacent, healthy tissue.

Quantification of tumor fluorescence during intraoperative optical cancer imaging

Intraoperative optical cancer imaging is an emerging technology in which surgeons employ fluorophores to visualize tumors, identify tumor-positive margins and lymph nodes containing metastases. This study compares instrumentation to measure tumor fluorescence. Three imaging systems (Spectropen, Glomax, Flocam) measured and quantified fluorescent signal-to-background ratios (SBR) in vitro, murine xenografts, tissue phantoms and clinically. Evaluation criteria included the detection of small changes in fluorescence, sensitivity of signal detection at increasing depths and practicality of use. In vitro, spectroscopy was superior in detecting incremental differences in fluorescence than luminescence and digital imaging (Ln[SBR] = 6.8 ± 0.6, 2.4 ± 0.3, 2.6 ± 0.1, p = 0.0001). In fluorescent tumor cells, digital imaging measured higher SBRs than luminescence (6.1 ± 0.2 vs. 4.3 ± 0.4, p = 0.001). Spectroscopy was more sensitive than luminometry and digital imaging in identifying murine tumor fluorescence (SBR = 41.7 ± 11.5, 5.1 ± 1.8, 4.1 ± 0.9, p = 0.0001), and more sensitive than digital imaging at detecting fluorescence at increasing depths (SBR = 7.0 ± 3.4 vs. 2.4 ± 0.5, p = 0.03). Lastly, digital imaging was the most practical and least time-consuming. All methods detected incremental differences in fluorescence. Spectroscopy was the most sensitive for small changes in fluorescence. Digital imaging was the most practical considering its wide field of view, background noise filtering capability, and sensitivity to increasing depth.