uPAR-targeted optical imaging contrasts as theranostic agents for tumor margin detection

Potential Application Prospects of Biomolecule-Modified Two-Dimensional Chiral Nanomaterials in Biomedicine

Chirality, one of the most fundamental properties of natural molecules, plays a significant role in biochemical reactions. Nanomaterials with chiral characteristics have superior properties, such as catalytic properties, optoelectronic properties, and photothermal properties, which have significant potential for specific applications in nanomedicine. Biomolecular modifications such as nucleic acids, peptides, proteins, and polysaccharides are sources of chirality for nanomaterials with great potential for application in addition to intrinsic chirality, artificial macromolecules, and metals. Two-dimensional (2D) nanomaterials, as opposed to other dimensions, due to proper surface area, extensive modification sites, drug loading potential, and simplicity of preparation, are prepared and utilized in diagnostic applications, drug delivery research, and tumor therapy. Current advanced studies on 2D chiral nanomaterials for biomedicine are focused on novel chiral development, structural control, and materials sustainability applications. However, despite the advances in biomedical research, chiral 2D nanomaterials still confront challenges such as the difficulty of synthesis, quality control, batch preparation, chiral stability, and chiral recognition and selectivity. This review aims to provide a comprehensive overview of the origins, synthesis, applications, and challenges of 2D chiral nanomaterials with biomolecules as cargo and chiral modifications and highlight their potential roles in biomedicine.

A novel urokinase plasminogen activator receptor-targeted peptide-based probe for in-vivo molecular imaging of glioblastoma

AIM

The urokinase plasminogen activator receptor (uPAR) is a promising biomarker for cancer diagnosis and therapy. We herein fabricated a new type of uPAR-targeted imaging probe Al18F-NOTA-VC and preliminarily evaluated its potential application in PET imaging of the glioma model in vivo.

METHODS

Peptide VC was synthesized and identified by MALDI-TOF-MS. The IC50 between VC/precursor NOTA-VC and uPAR was then determined before the synthesis and purification of Al18F-NOTA-VC, followed by further studies of in-vitro properties of Al18F-NOTA-VC. Meanwhile, the AE105-based probe followed a similar procedure in-vitro test. Finally, the PET imaging properties, including uPAR-targeting ability and the metabolism of Al18F-NOTA-VC, were investigated.

RESULTS

The VC and NOTA-VC were obtained successfully and demonstrated a good affinity with uPAR. Followed by Al18F labeling successfully, excellent properties, including the serum stability, water solubility, and specificity of Al18F-NOTA-VC, were obtained in-vitro test compared with AE105 based probe. An excellent tumor uptake and renal excretion data of Al18F-NOTA-VC were acquired from in-vivo U87MG tumor model PET imaging, consistent with the subsequent biodistribution study.

CONCLUSION

In addition to the excellent specificity and high tumor/normal tissue contrast for uPAR-targeted PET imaging of U87MG tumor, Al18F-NOTA-VC possessed promising clearance ability by renal system route. These excellent properties facilitated Al18F-NOTA-VC to be a promising imaging agent for uPAR high-expressing tumors and, thus, provided a paradigm for developing peptide-based probes for uPAR-associated disease diagnosis.

Side-by-Side Comparison of uPAR-Targeting Optical Imaging Antibodies and Antibody Fragments for Fluorescence-Guided Surgery of Solid Tumors

PURPOSE

Radical resection is paramount for curative oncological surgery. Fluorescence-guided surgery (FGS) aids in intraoperative identification of tumor-positive resection margins. This study aims to assess the feasibility of urokinase plasminogen activator receptor (uPAR) targeting antibody fragments for FGS in a direct comparison with their parent IgG in various relevant in vivo models.

PROCEDURES

Humanized anti-uPAR monoclonal antibody MNPR-101 (uIgG) was proteolytically digested into F(ab')2 and Fab fragments named uFab2 and uFab. Surface plasmon resonance (SPR) and cell assays were used to determine in vitro binding before and after fluorescent labeling with IRDye800CW. Mice bearing subcutaneous HT-29 human colonic cancer cells were imaged serially for up to 120 h after fluorescent tracer administration. Imaging characteristics and ex vivo organ biodistribution were further compared in orthotopic pancreatic ductal adenocarcinoma (BxPc-3-luc2), head-and-neck squamous cell carcinoma (OSC-19-luc2-GFP), and peritoneal carcinomatosis (HT29-luc2) models using the clinical Artemis fluorescence imaging system.

RESULTS

Unconjugated and conjugated uIgG, uFab2, and uFab specifically recognized uPAR in the nanomolar range as determined by SPR and cell assays. Subcutaneous tumors were clearly identifiable with tumor-to-background ratios (TBRs) > 2 after 72 h for uIgG-800F and 24 h for uFab2-800F and uFab-800F. For the latter two, mean fluorescence intensities (MFIs) dipped below predetermined threshold after 72 h and 36 h, respectively. Tumors were easily identified in the orthotopic models with uIgG-800F consistently having the highest MFIs and uFab2-800F and uFab-800F having similar values. In biodistribution studies, kidney and liver fluorescence approached tumor fluorescence after uIgG-800F administration and surpassed tumor fluorescence after uFab2-800F or uFab-800F administration, resulting in interference in the abdominal orthotopic mouse models.

CONCLUSIONS

In a side-by-side comparison, FGS with uPAR-targeting antibody fragments compared with the parent IgG resulted in earlier tumor visualization at the expense of peak fluorescence intensity.

Near-infrared-dye labeled tumor vascular-targeted dimer GEBP11 peptide for image-guided surgery in gastric cancer

Introduction

Positive resection margins occur in about 2.8%-8.2% gastric cancer surgeries and is associated with poor prognosis. Intraoperative guidance using Nearinfrared (NIR) fluorescence imaging is a promising technique for tumor detection and margin assessment. The goal of this study was to develop a tumor-specific probe for real-time intraoperative NIR fluorescence imaging guidance.

Methods

The tumor vascular homing peptide specific for gastric cancer, GEBP11, was conjugated with a near-infrared fluorophore, Cy5.5. The binding specificity of the GEBP11 probes to tumor vascular endothelial cells were confirmed by immunofluorescent staining. The ability of the probe to detect tumor lesions was evaluated in two xenograft models. An orthotopic gastric cancer xenograft model was used to evaluate the efficacy of the GEBP11 NIR probes in real-time surgical guidance.

Results

In vitro assay suggested that both mono and dimeric GEBP11 NIR probes could bind specifically to tumor vascular epithelial cells, with dimeric peptides showed better affinity. In tumor xenograft mice, live imaging suggested that comparing with free Cy5.5 probe, significantly stronger NIR signals could be detected at the tumor site at 24-48h after injection of mono or dimeric GEBP11 probes. Dimeric GEBP11 probe showed prolonged and stronger NIR signals than mono GEBP11 probe. Biodistribution assay suggested that GEBP11 NIR probes were enriched in gastric cancer xenografts. Using dimeric GEBP11 NIR probes in real-time surgery, the tumor margins and peritoneal metastases could be clearly visualized. Histological examination confirmed the complete resection of the tumor.

Conclusion

(GEBP11)2-ACP-Cy5.5 could be a potential useful probe for intraoperative florescence guidance in gastric cancer surgery.

Molecular Imaging and Nanotechnology-Emerging Tools in Diagnostics and Therapy

Personalized medicine is emerging as a new goal in the diagnosis and treatment of diseases. This approach aims to establish differences between patients suffering from the same disease, which allows to choose the most effective treatment. Molecular imaging (MI) enables advanced insight into molecule interactions and disease pathology, improving the process of diagnosis and therapy and, for that reason, plays a crucial role in personalized medicine. Nanoparticles are widely used in MI techniques due to their size, high surface area to volume ratio, and multifunctional properties. After conjugation to specific ligands and drugs, nanoparticles can transport therapeutic compounds directly to their area of action and therefore may be used in theranostics—the simultaneous implementation of treatment and diagnostics. This review summarizes different MI techniques, including optical imaging, ultrasound imaging, magnetic resonance imaging, nuclear imaging, and computed tomography imaging with theranostics nanoparticles. Furthermore, it explores the potential use of constructs that enables multimodal imaging and track diseases in real time.

Chemotherapeutic nanomaterials in tumor boundary delineation: Prospects for effective tumor treatment

Accurately delineating tumor boundaries is key to predicting survival rates of cancer patients and assessing response of tumor microenvironment to various therapeutic techniques such as chemotherapy and radiotherapy. This review discusses various strategies that have been deployed to accurately delineate tumor boundaries with particular emphasis on the potential of chemotherapeutic nanomaterials in tumor boundary delineation. It also compiles the types of tumors that have been successfully delineated by currently available strategies. Finally, the challenges that still abound in accurate tumor boundary delineation are presented alongside possible perspective strategies to either ameliorate or solve the problems. It is expected that the information communicated herein will form the first compendious baseline information on tumor boundary delineation with chemotherapeutic nanomaterials and provide useful insights into future possible paths to advancing current available tumor boundary delineation approaches to achieve efficacious tumor therapy.

The Urokinase Receptor (uPAR) as a "Trojan Horse" in Targeted Cancer Therapy: Challenges and Opportunities

Simple Summary

Discovered more than three decades ago, the urokinase-type plasminogen activator receptor (uPAR) has now firmly established itself as a versatile molecular target holding promise for the treatment of aggressive malignancies. The copious abundance of uPAR in virtually all human cancerous tissues versus their healthy counterparts has fostered a gradual shift in the therapeutic landscape targeting this receptor from function inhibition to cytotoxic approaches to selectively eradicate the uPAR-expressing cells by delivering a targeted cytotoxic insult. Multiple avenues are being explored in a preclinical setting, including the more innovative immune- or stroma targeting therapies. This review discusses the current state of these strategies, their potentialities, and challenges, along with future directions in the field of uPAR targeting.

Abstract

One of the largest challenges to the implementation of precision oncology is identifying and validating selective tumor-driving targets to enhance the therapeutic efficacy while limiting off-target toxicity. In this context, the urokinase-type plasminogen activator receptor (uPAR) has progressively emerged as a promising therapeutic target in the management of aggressive malignancies. By focalizing the plasminogen activation cascade and subsequent extracellular proteolysis on the cell surface of migrating cells, uPAR endows malignant cells with a high proteolytic and migratory potential to dissolve the restraining extracellular matrix (ECM) barriers and metastasize to distant sites. uPAR is also assumed to choreograph multiple other neoplastic stages via a complex molecular interplay with distinct cancer-associated signaling pathways. Accordingly, high uPAR expression is observed in virtually all human cancers and is frequently associated with poor patient prognosis and survival. The promising therapeutic potential unveiled by the pleiotropic nature of this receptor has prompted the development of distinct targeted intervention strategies. The present review will focus on recently emerged cytotoxic approaches emphasizing the novel technologies and related limits hindering their application in the clinical setting. Finally, future research directions and emerging opportunities in the field of uPAR targeting are also discussed.

Targeting the Urokinase-Type Plasminogen Activator Receptor (uPAR) in Human Diseases With a View to Non-invasive Imaging and Therapeutic Intervention

The interaction between the serine protease urokinase-type plasminogen activator (uPA) and its glycolipid-anchored receptor (uPAR) focalizes plasminogen activation to cell surfaces, thereby regulating extravascular fibrinolysis, cell adhesion, and migration. uPAR belongs to the Ly6/uPAR (LU) gene superfamily and the high-affinity binding site for uPA is assembled by a dynamic association of its three consecutive LU domains. In most human solid cancers, uPAR is expressed at the invasive areas of the tumor-stromal microenvironment. High levels of uPAR in resected tumors or shed to the plasma of cancer patients are robustly associated with poor prognosis and increased risk of relapse and metastasis. Over the years, a plethora of different strategies to inhibit uPA and uPAR function have been designed and investigated in vitro and in vivo in mouse models, but so far none have been implemented in the clinics. In recent years, uPAR-targeting with the intent of cytotoxic eradication of uPAR-expressing cells have nonetheless gained increasing momentum. Another avenue that is currently being explored is non-invasive imaging with specific uPAR-targeted reporter-molecules containing positron emitting radionuclides or near-infrared (NIR) florescence probes with the overarching aim of being able to: (i) localize disease dissemination using positron emission tomography (PET) and (ii) assist fluorescence guided surgery using optical imaging. In this review, we will discuss these advancements with special emphasis on applications using a small 9-mer peptide antagonist that targets uPAR with high affinity.

In Vivo Evaluation of a Miniaturized Fluorescence Molecular Tomography (FMT) Endoscope for Breast Cancer Detection Using Targeted Nanoprobes

In this study, in vivo animal experiments with 12 nude mice bearing breast-cancer-patient-tissue-derived xenograft (PDX) tumors were performed aiming to verify the imaging capability of a novel miniaturized fluorescence molecular tomography (FMT) endoscope, in combination with targeted nanoparticle–near-infrared (NIR) dye conjugates. Tumor-bearing mice were divided into two groups by systematic injection with urokinase plasminogen activator receptor-targeted (n = 7) and nontargeted (n = 5) imaging nanoprobes as a contrast agent, respectively. Each mouse was imaged at 6, 24, and 48 h following the injection of nanoprobes using the FMT endoscope. The results show that systemic delivery of targeted nanoprobes produced a 4-fold enhancement in fluorescence signals from tumors, compared with tumors that received nontargeted nanoprobes. This study indicates that our miniaturized FMT endoscope, coupled with the targeted nanoparticle–NIR dye conjugates as a contrast agent, has high sensitivity and specificity, and thus great potential to be used for image-guided detection and removal of a primary tumor and local metastatic tumors during surgery.

Molecular imaging of the urokinase plasminogen activator receptor: opportunities beyond cancer

The urokinase plasminogen activator receptor (uPAR) plays a multifaceted role in almost any process where migration of cells and tissue-remodeling is involved such as inflammation, but also in diseases as arthritis and cancer. Normally, uPAR is absent in healthy tissues. By its carefully orchestrated interaction with the protease urokinase plasminogen activator and its inhibitor (plasminogen activator inhibitor-1), uPAR localizes a cascade of proteolytic activities, enabling (patho)physiologic cell migration. Moreover, via the interaction with a broad range of cell membrane proteins, like vitronectin and various integrins, uPAR plays a significant, but not yet completely understood, role in differentiation and proliferation of cells, affecting also disease progression. The implications of these processes, either for diagnostics or therapeutics, have received much attention in oncology, but only limited beyond. Nonetheless, the role of uPAR in different diseases provides ample opportunity to exploit new applications for targeting. Especially in the fields of oncology, cardiology, rheumatology, neurology, and infectious diseases, uPAR-targeted molecular imaging could offer insights for new directions in diagnosis, surveillance, or treatment options.

Near-IR emissive rare-earth nanoparticles for guided surgery

Intraoperative image-guided surgery (IGS) has attracted extensive research interests in determination of tumor margins from surrounding normal tissues. Introduction of near infrared (NIR) fluorophores into IGS could significantly improve the in vivo imaging quality thus benefit IGS. Among the reported NIR fluorophores, rare-earth nanoparticles exhibit unparalleled advantages in disease theranostics by taking advantages such as large Stokes shift, sharp emission spectra, and high chemical/photochemical stability. The recent advances in elements doping and morphologies controlling endow the rare-earth nanoparticles with intriguing optical properties, including emission span to NIR-II region and long life-time photoluminescence. Particularly, NIR emissive rare earth nanoparticles hold advantages in reduction of light scattering, photon absorption and autofluorescence, largely improve the performance of nanoparticles in biological and pre-clinical applications. In this review, we systematically compared the benefits of RE nanoparticles with other NIR probes, and summarized the recent advances of NIR emissive RE nanoparticles in bioimaging, photodynamic therapy, drug delivery and NIR fluorescent IGS. The future challenges and promises of NIR emissive RE nanoparticles for IGS were also discussed.

Tumor Targeting Chemo- and Photodynamic Therapy Packaged in Albumin for Enhanced Anti-Tumor Efficacy

PURPOSE

Combination therapy for tumors is an important and promising strategy to improve therapeutic efficiency. This study aims at combining tumor targeting, chemo-, and photodynamic therapies to improve the anti-tumor performance.

PATIENTS AND METHODS

Human serum albumin (HSA), as a nontoxic and biodegradable drug carrier, was used to load hydrophobic photosensitizers (mono-substituted β-4-pyridyloxy phthalocyanine zinc, mPPZ) by a dilution-incubation-purification (DIP) strategy to form molecular complex HSA:mPPZ. This complex was cross-linked as nanoparticles, and then chemotherapy drug doxorubicin (DOX) was adsorbed into the nanoparticles to achieve combined photodynamic therapy and chemotherapy. Next, the surface of the obtained composite was modified by a tumor surface receptor (urokinase receptor) targeting agent (ATF-HSA) using a noncovalent method to obtain the final product (ATF-HSA@HSA:mPPZ:DOX nanoparticles, AHmDN).

RESULTS

AHmDN exhibited strong stability, remarkable cytotoxicity and higher uptake to tumor cells. Cell imaging analysis indicated that DOX was separated from AHmDN and uniformly distributed in cell nucleus while mPPZ localized in cytoplasm. The PDT activity of all the samples had been confirmed by the detection of intracellular ROS. In animal experiments, AHmDN was demonstrated to have a prominent tumor-targeting effect using a 3D imaging system. In addition, the enhanced antitumor effect of AHmDN in tumor-bearing mice was also been observed. Importantly, the tumor-targeting effect of such nanoparticles lasted for about 14 days after one injection.

CONCLUSION

These albumin nanoparticles with combined functions of tumor targeting, chemotherapy and photodynamic therapy can highly enhance the anti-tumor effect. This drug delivery system can be applied to package other hydrophobic photosensitizers and chemotherapy drugs for improving therapeutic efficacy to tumors.

Improved surgical resection of metastatic pancreatic cancer using uPAR targeted in vivo fluorescent guidance: comparison with traditional white light surgery

Pancreatic cancer remains one of the deadliest cancers. The five-year survival rates have been reported as 3%. Radical surgical tumor resection is critical for improved outcome and the low survival rate for pancreatic cancer is due to lack of other effective treatments and here optical guided surgery could be a solution for better surgical outcome. In the present study, we targeted the urokinase plasminogen activator receptor (uPAR) with a peptide conjugated with the fluophore ICG (ICG-Glu-Glu-AE105) for optical imaging. In the first part of the study we aimed to validate ICG-Glu-Glu-AE105 for resection of the primary tumor and metastases in an orthotopic human xenograft pancreatic cancer model. In the second part of the study we aimed to investigate if fluorescent-guided imaging could locate additional metastases following conventional removal of metastasis under normal white light surgery.

Our study showed that ICG-Glu-Glu-AE105 was an excellent probe for intraoperative optical imaging with a mean tumor-to-background ratio (TBR) for the primary tumor of 3.5 and a TBR for the metastases of 3.4. Further, a benefit using intraoperative fluorescent guidance yielded identification of an additional 14% metastases compared to using normal white light surgery. In 4 of 8 mice there were identified additional metastases with uPAR optical imaging compared to white light.

In conclusion, the uPAR-targeted optical probe ICG-Glu-Glu-AE105 enables intraoperative optical cancer imaging, including robotic surgery, and may be a benefit during intended radical resection of disseminated pancreas cancer by finding more metastasis than with traditional white light surgery.

Nanoscale systems for local drug delivery

Many diseases and conditions affect a relatively localized area of the body. They can be treated either by direct deposition of drug in the target area, or by giving the drug systemically. Here we review nanoparticle-based approaches to achieving both. We highlight advantages and disadvantages that nanoscale solutions have for locally administered therapies, with emphasis on the former. We discuss strategies to enable systemically delivered nanoparticles to deliver their payloads at specific locations in the body, including triggering (local and remote) and targeting.

Emerging Fluorescent Molecular Tracers to Guide Intra-Operative Surgical Decision-Making

Fluorescence imaging is an emerging technology that can provide real-time information about the operating field during cancer surgery. Non-specific fluorescent agents, used for the assessment of blood flow and sentinel lymph node detection, have so far dominated this field. However, over the last decade, several clinical studies have demonstrated the great potential of targeted fluorescent tracers to visualize tumor lesions in a more specific way. This has led to an exponential growth in the development of novel molecular fluorescent contrast agents. In this review, the design of fluorescent molecular tracers will be discussed, with particular attention for agents and approaches that are of interest for clinical translation.

Nanoparticle Binding to Urokinase Receptor on Cancer Cell Surface Triggers Nanoparticle Disintegration and Cargo Release

Cancer cell expresses abundant surface receptors. These receptors are important targets for cancer treatment and imaging applications. Our goal here is to develop nanoparticles with cargo loading and tumor targeting capability.

Methods: A peptide targeting at cancer cell surface receptor (urokinase receptor, uPAR) was expressed in fusion with albumin (diameter of ~7 nm), and the fusion protein was assembled into nanoparticles with diameter of 40 nm, either in the presence or absence of cargo molecules, by a novel preparation method. An important feature of this method is that the nanoparticles were stabilized by hydrophobic interaction of the fusion protein and no covalent linking agent was used in the preparation. The stability, the cargo release, in vitro and in vivo properties of such formed nanoparticles were characterized by transmission electron microscopy, dynamic light scattering, gel shift assay, laser scanning confocal microscopy and 3D fluorescent molecular tomography.

Results: The nanoparticles were stable for more than two weeks in aqueous buffer, even in the buffer containing 10% fetal bovine serum. Interestingly, in the presence of urokinase receptor, the uPAR-targeting nanoparticle disintegrated into 7.5 nm fragments and released its cargo, but not the non-targeting nanoparticles made from albumin by the same preparation method. Such nanoparticles also showed higher uptake and cytotoxicity to the receptor-expressing cancer cells in vitro and higher tumor accumulation in xenografted tumor-bearing mice in vivo compared to the non-targeting nanoparticles.

Conclusion: Our results demonstrate a new function of cell surface receptor as a responsive trigger to disassemble nanoparticles, besides its common use to enrich targeting agents. Such nanoparticles were thus named receptor-responsive nanoparticles (RRNP).

Peptide-functionalized NaGdF4 nanoparticles for tumor-targeted magnetic resonance imaging and effective therapy

Metallic nanoparticles showed potent efficacy for diagnosis and therapy of cancer, but their clinical applications are limited by their poor tumor-targeting ability. Herein, peptide-functionalized 9 nm NaGdF₄ nanoparticles (termed as, NaGdF₄@bp-peptide NPs) have been synthesized through the Gd–phosphate coordination reaction of the spherical NaGdF₄ nanoparticles with phosphopeptides (sequence: KLAKLAKKLAKLAKG(p-S)GAKRGARSTA, p-S means phosphorylated serine) including a p32 protein binding motif incorporating a cell-penetrating function, and a proapoptotic domain. The NaGdF₄@bp-peptide NPs are ready to be efficiently internalized by cancer cells; they show a much higher cytotoxicity in MCF-7 breast cancer cells than the casein phosphopeptide (CPP) modified NaGdF₄ nanoparticles (termed as, NaGdF₄@CPP NPs). Using mouse-bearing MCF-7 breast cancer as a model system, the in vivo experimental results demonstrate that NaGdF₄@bp-peptide NPs have integration of T₁-weighted magnetic resonance imaging (MRI) contrast and tumor-targeting functionalities, and are able to suppress tumor growth without causing systemic toxicity.

NaGdF₄@bp-peptide nanoparticles have been used as a T₁-weighted MR contrast agent with active-tumor targeting and antitumor ability.

Advantages of patient-derived orthotopic mouse models and genetic reporters for developing fluorescence-guided surgery

Fluorescence-guided surgery can enhance the surgeon's ability to achieve a complete oncologic resection. There are a number of tumor-specific probes being developed with many preclinical mouse models to evaluate their efficacy. The current review discusses the different preclinical mouse models in the setting of probe evaluation and highlights the advantages of patient-derived orthotopic xenografts (PDOX) mouse models and genetic reporters to develop fluorescence-guided surgery.

How can nanotechnology help the fight against breast cancer?

In this review we provide a broad overview on the use of nanotechnology for the fight against breast cancer (BC). Nowadays, detection, diagnosis, treatment, and prevention may be possible thanks to the application of nanotechnology to clinical practice. Taking into consideration the different forms of BC and the disease status, nanomaterials can be designed to meet the most forefront objectives of modern therapy and diagnosis. We have analyzed in detail three main groups of nanomaterial applications for BC treatment and diagnosis. We have identified several types of drugs successfully conjugated with nanomaterials. We have analyzed the main important imaging techniques and all nanomaterials used to help the non-invasive, early detection of the lesions. Moreover, we have examined theranostic nanomaterials as unique tools, combining imaging, detection, and therapy for BC. This state of the art review provides a useful guide depicting how nanotechnology can be used to overcome the current barriers in BC clinical practice, and how it will shape the future scenario of treatments, prevention, and diagnosis, revolutionizing the current approaches, e.g., reducing the suffering related to chemotherapy.

Theranostic Nanoparticles for Tracking and Monitoring Disease State

The development of novel nanoparticles consisting of both diagnostic and therapeutic components has increased over the past decade. These "theranostic" nanoparticles have been tailored toward one or more types of imaging modalities and have been developed for optical imaging, magnetic resonance imaging, ultrasound, computed tomography, and nuclear imaging comprising both single-photon computed tomography and positron emission tomography. In this review, we focus on state-of-the-art theranostic nanoparticles that are capable of both delivering therapy and self-reporting/tracking disease through imaging. We discuss challenges and the opportunity to rapidly adjust treatment for individualized medicine.

Using Atomic Force Microscopy to Predict Tumor Specificity of ICAM1 Antibody-Directed Nanomedicines

Atomic force microscopy (AFM) is a powerful tool to detect in vitro antibody-antigen interactions. To date, however, AFM-measured antibody-antigen interactions have yet to be exploited to predict in vivo tumor specificity of antibody-directed nanomedicines. In this study, we have utilized AFM to directly measure the biomechanical interaction between live triple negative breast cancer (TNBC) cells and an antibody against ICAM1, a recently identified TNBC target. For the first time, we provide proof-of-principle evidence that in vitro TNBC cell-ICAM1 antibody binding force measured by AFM on live cells more precisely correlates with in vivo tumor accumulation and therapeutic efficacy of ICAM1 antibody-directed liposomes than ICAM1 gene and surface protein overexpression levels. These studies demonstrate that live cell-antibody binding force measurements may be used as a novel in vitro metric for predicting the in vivo tumor recognition of antibody-directed nanomedicines.

Research progresses on the functional polypeptides in the detection and imaging of breast cancer

Polypeptides as functional groups continue to garner significant interest in the detection and imaging of breast cancer, working as recognition elements, signal sources, building blocks and therapeutic reagents, etc.

Targeted Delivery of siRNA Therapeutics to Malignant Tumors

Over the past 20 years, a diverse group of ligands targeting surface biomarkers or receptors has been identified with several investigated to target siRNA to tumors. Many approaches to developing tumor-homing peptides, RNA and DNA aptamers, and single-chain variable fragment antibodies by using phage display, in vitro evolution, and recombinant antibody methods could not have been imagined by researchers in the 1980s. Despite these many scientific advances, there is no reason to expect that the ligand field will not continue to evolve. From development of ligands based on novel or existing biomarkers to linking ligands to drugs and gene and antisense delivery systems, several fields have coalesced to facilitate ligand-directed siRNA therapeutics. In this review, we discuss the major categories of ligand-targeted siRNA therapeutics for tumors, as well as the different strategies to identify new ligands.

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.

UPAR targeted molecular imaging of cancers with small molecule-based probes

Molecular imaging can allow the non-invasive characterization and measurement of biological and biochemical processes at the molecular and cellular levels in living subjects. The imaging of specific molecular targets that are associated with cancers could allow for the earlier diagnosis and better treatment of diseases. Small molecule-based probes play prominent roles in biomedical research and have high clinical translation ability. Here, with an emphasis on small molecule-based probes, we review some recent developments in biomarkers, imaging techniques and multimodal imaging in molecular imaging and highlight the successful applications for molecular imaging of cancers.

Doxorubicin-loaded redox-responsive micelles based on dextran and indomethacin for resistant breast cancer

Multidrug resistance (MDR) against chemotherapeutic agents has become one of the major obstacles to successful cancer therapy and MDR-associated proteins (MRPs)-mediated drug efflux is the key factor for MDR. In this study, a redox-responsive polymer based on dextran (DEX) and indomethacin (IND), which could reduce MRPs-mediated efflux of chemotherapeutics, was synthesized, and the obtained polymer could spontaneously form stable micelles with well-defined core-shell structure and a uniform size distribution with an average diameter of 50 nm and effectively encapsulate doxorubicin (DOX); the micelles contain a disulfide bridge (cystamine, SS) between IND and DEX (DEX-SS-IND). In vitro drug release results indicated that DEX-SS-IND/DOX micelles could maintain good stability in a stimulated normal physiological environment and promptly depolymerized and released DOX in a reducing environment. After incubating DEX-SS-IND/DOX micelles with drug-resistant tumor (MCF-7/ADR) cells, the intracellular accumulation and retention of DOX were significantly increased under the synergistic effects of redox-responsive delivery and the inhibitory effect of IND on MRPs. In vitro cytotoxicity showed that DEX-SS-IND/DOX micelles exhibited higher cytotoxicity against MCF-7/ADR cells. Moreover, DEX-SS-IND/DOX micelles showed significantly enhanced inhibition of tumor in BALB/c nude mice bearing MCF-7/ADR tumors and reduced systemic toxicity. Overall, the cumulative evidence indicates that DEX-SS-IND/DOX micelles hold significant promise for overcoming MDR for cancer therapy.

A Systematic Evaluation of Factors Affecting Extracellular Vesicle Uptake by Breast Cancer Cells

Extracellular vesicles (EVs) are nanometer-scale particles that are secreted by cells and mediate intercellular communication by transferring biomolecules between cells. Harnessing this mechanism for therapeutic biomolecule delivery represents a promising frontier for regenerative medicine and other clinical applications. One challenge to realizing this goal is that to date, our understanding of which factors affect EV uptake by recipient cells remains incomplete. In this study, we systematically investigated such delivery questions in the context of breast cancer cells, which are one of the most well-studied cell types with respect to EV delivery and therefore comprise a facile model system for this investigation. By displaying various targeting peptides on the EV surface, we observed that although displaying GE11 on EVs modestly increased uptake by MCF-7 cells, neuropeptide Y (NPY) display had no effect on uptake by the same cells. In contrast, neurotensin (NTS) and urokinase plasminogen activator (uPA) display reduced EV uptake by MDA-MB-231 cells. Interestingly, EV uptake rate did not depend on the source of the EVs; breast cancer cells demonstrated no increase in uptake on administration of breast cancer-derived EVs in comparison to HEK293FT-derived EVs. Moreover, EV uptake was greatly enhanced by delivery in the presence of polybrene and spinoculation, suggesting that maximal EV uptake rates are much greater than those observed under basal conditions in cell culture. By investigating how the cell's environment might provide cues that impact EV uptake, we also observed that culturing cells on soft matrices significantly enhanced EV uptake, compared to culturing on stiff tissue culture polystyrene. Each of these observations provides insights into the factors impacting EV uptake by breast cancer cells, while also providing a basis of comparison for systematically evaluating and perhaps enhancing EV uptake by various cell types.

Cell targeting peptides as smart ligands for targeting of therapeutic or diagnostic agents: a systematic review

Cell targeting peptides (CTP) are small peptides which have high affinity and specificity to a cell or tissue targets. They are typically identified by using phage display and chemical synthetic peptide library methods. CTPs have attracted considerable attention as a new class of ligands to delivery specifically therapeutic and diagnostic agents, because of the fact they have several advantages including easy synthesis, smaller physical sizes, lower immunogenicity and cytotoxicity and their simple and better conjugation to nano-carriers and therapeutic or diagnostic agents compared to conventional antibodies. In this systematic review, we will focus on the basic concepts concerning the use of cell-targeting peptides (CTPs), following the approaches of selecting them from peptide libraries. We discuss several developed strategies for cell-specific delivery of different cargos by CTPs, which are designed for drug delivery and diagnostic applications.

Be Active or Not: the Relative Contribution of Active and Passive Tumor Targeting of Nanomaterials

Malignant tumor (cancer) remains as one of the deadliest diseases throughout the world, despite its overall mortality drops. Nanomaterials (NMs) have been widely studied as diagnostic and/or therapeutic agents for tumors. A feature of NMs, compared to small molecules, is that NMs can be concentrated passively in tumors through enhanced permeability and retention (EPR) effect. In the meantime, NMs can be engineered to target toward tumor specific markers in an active manner, e.g., receptor-mediated targeting. The relative contribution of the EPR effect and the receptor-mediated targeting to NM accumulation in tumor tissues has not been clearly defined yet. Here, we tackle this fundamental issue by reviewing previous studies. First, we summarize the current knowledge on these two tumor targeting strategies of NMs, and on how NMs arrive to tumors from blood circulation. We then demonstrate that contribution of the active and passive effects to total accumulation of NMs in tumors varies with time. Over time, the receptor-mediated targeting contributes more than the EPR effect with a ratio of 3 in the case of urokinase-type plasminogen activator receptor (uPAR)-mediated targeting and human serum albumin (HSA)-mediated EPR effect. Therefore, this review highlights the dynamics of active and passive targeting of NMs on their accumulation at tumor sites, and is valuable for future design of NMs in cancer diagnosis and treatment.

Prognostic Impact of Urokinase Plasminogen Activator Receptor Expression in Pancreatic Cancer: Malignant Versus Stromal Cells

The urokinase plasminogen activator receptor (uPAR) has been proposed as a potential prognostic factor for various malignancies. The aim of this study is to assess the prognostic value of uPAR expression in neoplastic and stromal cells of patients with pancreatic adenocarcinoma. Urokinase plasminogen activator receptor expression was determined by immunohistochemistry in 122 pancreatic ductal adenocarcinomas. Kaplan-Meier and Cox regression analyses were used to determine the association with survival. Respectively 66%, 82% and 62% of patients with pancreatic cancer expressed uPAR in neoplastic cells, stromal, and in both combined. Multivariate analysis showed a significant inverse association between uPAR expression in both neoplastic and stromal cells and overall survival. The prognostic impact of uPAR in stromal cells is substantial, but not as pronounced as that of uPAR expression in neoplastic cells. This study suggests a role for uPAR as a biomarker to single out higher risk subgroups of patients with pancreatic cancer.

Diverse Applications of Nanomedicine

The design and use of materials in the nanoscale size range for addressing medical and health-related issues continues to receive increasing interest. Research in nanomedicine spans a multitude of areas, including drug delivery, vaccine development, antibacterial, diagnosis and imaging tools, wearable devices, implants, high-throughput screening platforms, etc. using biological, nonbiological, biomimetic, or hybrid materials. Many of these developments are starting to be translated into viable clinical products. Here, we provide an overview of recent developments in nanomedicine and highlight the current challenges and upcoming opportunities for the field and translation to the clinic.

Current status of biomarker and targeted nanoparticle development: The precision oncology approach for pancreatic cancer therapy

Pancreatic cancer remains one of the major causes of cancer-related mortality. The majority of pancreatic cancer patients are diagnosed at the advanced stage with unresectable and drug resistant tumors. The new treatments with the combination of chemotherapy, molecular targeted therapy, and immunotherapy have shown modest effects on therapeutic efficacy and survival of the patients. Therefore, there is an urgent need to develop effective therapeutic approaches targeting highly heterogeneous pancreatic cancer cells and tumor microenvironments. Recent advances in biomarker targeted cancer therapy and image-guided drug delivery and monitoring treatment response using multifunctional nanoparticles, also referred to as theranostic nanoparticles, offer a new opportunity of effective detection and treatment of pancreatic cancer. Increasing evidence from preclinical studies has shown the potential of applications of theranostic nanoparticles for designing precision oncology approaches for pancreatic cancer therapy. In this review, we provide an update on the current understanding and strategies for the development of targeted therapy for pancreatic cancer using nanoparticle drug carriers. We address issues concerning drug delivery barriers in stroma rich pancreatic cancer and the potential approaches to improve drug delivery efficiency, therapeutic responses and tumor imaging. Research results presented in this review suggest the development of an integrated therapy protocol through image-guided and targeted drug delivery and therapeutic effect monitoring as a promising precision oncology strategy for pancreatic cancer treatment.

Mapping Sentinel Lymph Node Metastasis by Dual-probe Optical Imaging

Purpose: Sentinel lymph node biopsy (SLNB) has emerged as the preferred standard procedure in patients with breast cancer, melanoma and other types of cancer. Herein, we developed a method to intra-operatively map SLNs and differentiate tumor metastases within SLNs at the same time, with the aim to provide more accurate and real-time intraoperative guidance. Experimental Design: Hyaluronic acid (HA), a ligand of lymphatic vessel endothelial hyaluronan receptor (LYVE)-1, is employed as a SLN mapping agent after being conjugated with a near-infrared fluorophore (Cy5.5). Different sized HAs (5, 10 and 20K) were tested in normal mice and mice with localized inflammation to optimize LN retention time and signal to background ratio. Cetuximab, an antibody against epidermal growth factor receptor (EGFR), and trastuzumab, an antibody against human epidermal growth factor receptor 2 (HER2), were labeled with near-infrared fluorophore (IRDye800) for detecting metastatic tumors. LN metastasis model was developed by hock injection of firefly luciferase engineered human head neck squamous carcinoma cancer UM-SCC-22B cells or human ovarian cancer SKOV-3 cells. The metastases within LNs were confirmed by bioluminescence imaging (BLI). IRDye800-Antibodies were intravenously administered 24 h before local administration of Cy5.5-HA. Optical imaging was then performed to identify nodal metastases. Results: Binding of HA with LYVE-1 was confirmed by ELISA and fluorescence staining. HA with a size of 10K was chosen based on the favorable migration and retention profile. After sequential administration of IRDye800-antibodies intravenously and Cy5.5-HA locally to a mouse model with LN metastases and fluorescence optical imaging, partially metastasized LNs were successfully distinguished from un-metastasized LNs and fully tumor occupied LNs, based on the different signal patterns. Conclusions: Fluorophore conjugated HA is a potential lymphatic mapping agent for SLNB. Dual-tracer imaging with the combination of lymphatic mapping agents and tumor targeting agents can identify tumor metastases within SLNs, thus may provide accurate and real-time intra-operative guidance to spare the time spent waiting for a biopsy result.

Intraoperative Molecular Imaging of Lung Adenocarcinoma Can Identify Residual Tumor Cells at the Surgical Margins

PURPOSE

During lung surgery, identification of surgical margins is challenging. We hypothesized that molecular imaging with a fluorescent probe to pulmonary adenocarcinomas could enhance residual tumor during resection.

PROCEDURES

Mice with flank tumors received a contrast agent targeting folate receptor alpha. Optimal dose and time of injection was established. Margin detection was compared using traditional methods versus molecular imaging. A pilot study was then performed in three humans with lung adenocarcinoma.

RESULTS

The peak tumor-to-background ratio (TBR) of murine tumors was 3.9. Fluorescence peaked at 2 h and was not improved beyond 0.1 mg/kg. Traditional inspection identified 30% of mice with positive margins. Molecular imaging identified an additional 50% of residual tumor deposits (p < 0.05). The fluorescent probe visually enhanced all human tumors with a mean TBR of 3.5.

CONCLUSIONS

Molecular imaging is an important adjunct to traditional inspection to identify surgical margins after tumor resection.

Selecting Tumor-Specific Molecular Targets in Pancreatic Adenocarcinoma: Paving the Way for Image-Guided Pancreatic Surgery

PURPOSE

The purpose of this study was to identify suitable molecular targets for tumor-specific imaging of pancreatic adenocarcinoma.

PROCEDURES

The expression of eight potential imaging targets was assessed by the target selection criteria (TASC)-score and immunohistochemical analysis in normal pancreatic tissue (n = 9), pancreatic (n = 137), and periampullary (n = 28) adenocarcinoma.

RESULTS

Integrin αvβ6, carcinoembryonic antigen (CEA), epithelial growth factor receptor (EGFR), and urokinase plasminogen activator receptor (uPAR) showed a significantly higher (all p < 0.001) expression in pancreatic adenocarcinoma compared to normal pancreatic tissue and were confirmed by the TASC score as promising imaging targets. Furthermore, these biomarkers were expressed in respectively 88 %, 71 %, 69 %, and 67 % of the pancreatic adenocarcinoma patients.

CONCLUSIONS

The results of this study show that integrin αvβ6, CEA, EGFR, and uPAR are suitable targets for tumor-specific imaging of pancreatic adenocarcinoma.

Advances in fluorescent-image guided surgery

Fluorescence imaging is increasingly gaining intraoperative applications. Here, we highlight a few recent advances in the surgical use of fluorescent probes.

Nanoparticles in practice for molecular-imaging applications: An overview

Nanoparticles (NPs) are playing a progressively more significant role in multimodal and multifunctional molecular imaging. The agents like Superparamagnetic iron oxide (SPIO), manganese oxide (MnO), gold NPs/nanorods and quantum dots (QDs) possess specific properties like paramagnetism, superparamagnetism, surface plasmon resonance (SPR) and photoluminescence respectively. These specific properties make them able for single/multi-modal and single/multi-functional molecular imaging. NPs generally have nanomolar or micromolar sensitivity range and can be detected via imaging instrumentation. The distinctive characteristics of these NPs make them suitable for imaging, therapy and delivery of drugs. Multifunctional nanoparticles (MNPs) can be produced through either modification of shell or surface or by attaching an affinity ligand to the nanoparticles. They are utilized for targeted imaging by magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), positron emission tomography (PET), computed tomography (CT), photo acoustic imaging (PAI), two photon or fluorescent imaging and ultra sound etc. Toxicity factor of NPs is also a very important concern and toxic effect should be eliminated. First generation NPs have been designed, developed and tested in living subjects and few of them are already in clinical use. In near future, molecular imaging will get advanced with multimodality and multifunctionality to detect diseases like cancer, neurodegenerative diseases, cardiac diseases, inflammation, stroke, atherosclerosis and many others in their early stages. In the current review, we discussed single/multifunctional nanoparticles along with molecular imaging modalities.

STATEMENT OF SIGNIFICANCE

The present article intends to reveal recent avenues for nanomaterials in multimodal and multifunctional molecular imaging through a review of pertinent literatures. The topic emphasises on the distinctive characteristics of nanomaterial which makes them, suitable for biomedical imaging, therapy and delivery of drugs. This review is more informative of indicative technologies which will be helpful in a way to plan, understand and lead the nanotechnology related work.

Functionalized milk-protein-coated magnetic nanoparticles for MRI-monitored targeted therapy of pancreatic cancer

Engineered nanocarriers have emerged as a promising platform for cancer therapy. However, the therapeutic efficacy is limited by low drug loading efficiency, poor passive targeting to tumors, and severe systemic side effects. Herein, we report a new class of nanoconstructs based on milk protein (casein)-coated magnetic iron oxide (CNIO) nanoparticles for targeted and image-guided pancreatic cancer treatment. The tumor-targeting amino-terminal fragment (ATF) of urokinase plasminogen activator and the antitumor drug cisplatin (CDDP) were engineered on this nanoplatform. High drug loading (~25 wt%) and sustained release at physiological conditions were achieved through the exchange and encapsulation strategy. These ATF-CNIO-CDDP nanoparticles demonstrated actively targeted delivery of CDDP to orthotopic pancreatic tumors in mice. The effective accumulation and distribution of ATF-CNIO-CDDP was evidenced by magnetic resonance imaging, based on the T₂-weighted contrast resulting from the specific accumulation of ATF-CNIO-CDDP in the tumor. Actively targeted delivery of ATF-CNIO-CDDP led to improved therapeutic efficacy in comparison with free CDDP and nontargeted CNIO-CDDP treatment. Meanwhile, less systemic side effects were observed in the nanocarrier-treated groups than that in the group treated with free CDDP. Hematoxylin and Eosin and Sirius Red staining of tumor sections revealed the possible disruption of stroma during the treatment with ATF-CNIO-CDDP. Overall, our results suggest that ATF-CNIO-CDDP can be an effective theranostic platform for active targeting-enhanced and image-guided cancer treatment while simultaneously reducing the systemic toxicity.

Albumin-Mediated Biomineralization of Paramagnetic NIR Ag2S QDs for Tiny Tumor Bimodal Targeted Imaging in Vivo

Bimodal imaging has captured increasing interests due to its complementary characteristics of two kinds of imaging modalities. Among the various dual-modal imaging techniques, MR/fluorescence imaging has been widely studied owing to its high 3D resolution and sensitivity. There is, however, still a strong demand to construct biocompatible MR/fluorescence contrast agents with near-infrared (NIR) fluorescent emissions and high relaxivities. In this study, BSA-DTPA(Gd) derived from bovine serum albumin (BSA) as a novel kind of biotemplate is employed for biomineralization of paramagnetic NIR Ag2S quantum dots (denoted as Ag2S@BSA-DTPA(Gd) pQDs). This synthetic strategy is found to be bioinspired, environmentally benign, and straightforward. The obtained Ag2S@BSA-DTPA(Gd) pQDs have fine sizes (ca. 6 nm) and good colloidal stability. They exhibit unabated NIR fluorescent emission (ca. 790 nm) as well as high longitudinal relaxivity (r1 = 12.6 mM(-1) s(-1)) compared to that of commercial Magnevist (r1 = 3.13 mM(-1) s(-1)). In vivo tumor-bearing MR and fluorescence imaging both demonstrate that Ag2S@BSA-DTPA(Gd) pQDs have pronounced tiny tumor targeting capability. In vitro and in vivo toxicity study show Ag2S@BSA-DTPA(Gd) pQDs are biocompatible. Also, biodistribution analysis indicates they can be cleared from body mainly via liver metabolism. This protein-mediated biomineralized Ag2S@BSA-DTPA(Gd) pQDs presents great potential as a novel bimodal imaging contrast agent for tiny tumor diagnosis.

Green Tea Catechin-Based Complex Micelles Combined with Doxorubicin to Overcome Cardiotoxicity and Multidrug Resistance

Chemotherapy for cancer treatment has been demonstrated to cause some side effects on healthy tissues and multidrug resistance of the tumor cells, which greatly limits therapeutic efficacy. To address these limitations and achieve better therapeutic efficacy, combination therapy based on nanoparticle platforms provides a promising approach through delivering different agents simultaneously to the same destination with synergistic effect. In this study, a novel green tea catechin-based polyion complex (PIC) micelle loaded with doxorubicin (DOX) and (-)-Epigallocatechin-3-O-gallate (EGCG) was constructed through electrostatic interaction and phenylboronic acid-catechol interaction between poly(ethylene glycol)-block-poly(lysine-co-lysine-phenylboronic acid) (PEG-PLys/PBA) and EGCG. DOX was co-loaded in the PIC micelles through π-π stacking interaction with EGCG. The phenylboronic acid-catechol interaction endowed the PIC micelles with high stability under physiological condition. Moreover, acid cleavability of phenylboronic acid-catechol interaction in the micelle core has significant benefits for delivering EGCG and DOX to same destination with synergistic effects. In addition, benefiting from the oxygen free radicals scavenging activity of EGCG, combination therapy with EGCG and DOX in the micelle core could protect the cardiomyocytes from DOX-mediated cardiotoxicity according to the histopathologic analysis of hearts. Attributed to modulation of EGCG on P-glycoprotein (P-gp) activity, this kind of PIC micelles could effectively reverse multidrug resistance of cancer cells. These results suggested that EGCG based PIC micelles could effectively overcome DOX induced cardiotoxicity and multidrug resistance.

uPAR-targeted multimodal tracer for pre- and intraoperative imaging in cancer surgery

Pre- and intraoperative diagnostic techniques facilitating tumor staging are of paramount importance in colorectal cancer surgery. The urokinase receptor (uPAR) plays an important role in the development of cancer, tumor invasion, angiogenesis, and metastasis and over-expression is found in the majority of carcinomas. This study aims to develop the first clinically relevant anti-uPAR antibody-based imaging agent that combines nuclear (¹¹¹In) and real-time near-infrared (NIR) fluorescent imaging (ZW800-1). Conjugation and binding capacities were investigated and validated in vitro using spectrophotometry and cell-based assays. In vivo, three human colorectal xenograft models were used including an orthotopic peritoneal carcinomatosis model to image small tumors. Nuclear and NIR fluorescent signals showed clear tumor delineation between 24h and 72h post-injection, with highest tumor-to-background ratios of 5.0 ± 1.3 at 72h using fluorescence and 4.2 ± 0.1 at 24h with radioactivity. 1-2 mm sized tumors could be clearly recognized by their fluorescent rim. This study showed the feasibility of an uPAR-recognizing multimodal agent to visualize tumors during image-guided resections using NIR fluorescence, whereas its nuclear component assisted in the pre-operative non-invasive recognition of tumors using SPECT imaging. This strategy can assist in surgical planning and subsequent precision surgery to reduce the number of incomplete resections.

Gold Nanorods Based Air Scanning Electron Microscopy and Diffusion Reflection Imaging for Mapping Tumor Margins in Squamous Cell Carcinoma

A critical challenge arising during a surgical procedure for tumor removal is the determination of tumor margins. Gold nanorods (GNRs) conjugated to epidermal growth factor receptors (EGFR) (GNRs-EGFR) have long been used in the detection of cancerous cells as the expression of EGFR dramatically increases once the tissue becomes cancerous. Optical techniques for the identification of these GNRs-EGFR in tumor are intensively developed based on the unique scattering and absorption properties of the GNRs. In this study, we investigate the distribution of the GNRs in tissue sections presenting squamous cell carcinoma (SCC) to evaluate the SCC margins. Air scanning electron microscopy (airSEM), a novel, high resolution microscopy is used, enabling to localize and actually visualize nanoparticles on the tissue. The airSEM pictures presented a gradient of GNRs from the tumor to normal epithelium, spread in an area of 1 mm, suggesting tumor margins of 1 mm. Diffusion reflection (DR) measurements, performed in a resolution of 1 mm, of human oral SCC have shown a clear difference between the DR profiles of the healthy epithelium and the tumor itself.

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.

Preclinical evaluation of a urokinase plasminogen activator receptor-targeted nanoprobe in rhesus monkeys

Purpose

To translate a recombinant peptide containing the amino-terminal fragment (ATF) of urokinase plasminogen activator receptor-targeted magnetic iron oxide (IO) nanoparticles (uPAR-targeted human ATF-IONPs) into clinical applications, we conducted a pilot study to evaluate the toxicity and pharmacokinetics of this nanoparticle in normal rhesus monkeys.

Methods

We assessed the changes in the following: magnetic resonance imaging (MRI) signals from pretreatment stage to 14 days posttreatment, serum iron concentrations from 5 minutes posttreatment to 12 weeks posttreatment, routine blood examination and serum chemistry analysis results from pretreatment stage to 12 weeks after administration, and results of staining of the liver with Perls’ Prussian Blue and hematoxylin–eosin at 24 hours and 3 months posttreatment in two rhesus monkeys following an intravenous administration of the targeted nanoparticles either with a polyethylene glycol (ATF-PEG-IONP) or without a PEG (ATF-IONP) coating.

Results

The levels of alkaline phosphatase, alanine transaminase, and direct bilirubin in the two monkeys increased immediately after the administration of the IONPs but returned to normal within 20 days and stayed within the normal reference range 3 months after the injection. The creatinine levels of the two monkeys stayed within the normal range during the study. In addition, red blood cells, white blood cells, hemoglobin level, and platelets remained normal during the 3 months of the study.

Conclusion

All of the results suggest that a transient injury in terms of normal organ functions, but no microscopic necrotic lesions, was observed at a systemic delivery dose of 5 mg/kg of iron equivalent concentration in the acute phase, and that no chronic toxicity was found 3 months after the injection. Therefore, we conclude that uPAR-targeted IONPs have the potential to be used as receptor-targeted MRI contrasts as well as theranostic agents for the detection and treatment of human cancers in future studies.

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

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.

IGF1 Receptor Targeted Theranostic Nanoparticles for Targeted and Image-Guided Therapy of Pancreatic Cancer

Overcoming resistance to chemotherapy is a major and unmet medical challenge in the treatment of pancreatic cancer. Poor drug delivery due to stromal barriers in the tumor microenvironment and aggressive tumor biology are additional impediments toward a more successful treatment of pancreatic cancer. In attempts to address these challenges, we developed IGF1 receptor (IGF1R)-directed, multifunctional theranostic nanoparticles for targeted delivery of therapeutic agents into IGF1R-expressing drug-resistant tumor cells and tumor-associated stromal cells. These nanoparticles were prepared by conjugating recombinant human IGF1 to magnetic iron oxide nanoparticles (IONPs) carrying the anthracycline doxorubicin (Dox) as the chemotherapeutic payload. Intravenously administered IGF1-IONPs exhibited excellent tumor targeting and penetration in an orthotopic patient-derived xenograft (PDX) model of pancreatic cancer featuring enriched tumor stroma and heterogeneous cancer cells. IGF1R-targeted therapy using the theranostic IGF1-IONP-Dox significantly inhibited the growth of pancreatic PDX tumors. The effects of the intratumoral nanoparticle delivery and therapeutic responses in the orthotopic pancreatic PDX tumors could be detected by magnetic resonance imaging (MRI) with IONP-induced contrasts. Histological analysis showed that IGF1R-targeted delivery of Dox significantly inhibited cell proliferation and induced apoptotic cell death of pancreatic cancer cells. Therefore, further development of IGF1R-targeted theranostic IONPs and MRI-guided cancer therapy as a precision nanomedicine may provide the basis for more effective treatment of pancreatic cancer.

Dual actions of albumin packaging and tumor targeting enhance the antitumor efficacy and reduce the cardiotoxicity of doxorubicin in vivo

Doxorubicin (DOX) is an effective chemotherapy drug used to treat different types of cancers. However, DOX has severe side effects, especially life-threatening cardiotoxicity. We herein report a new approach to reduce the toxicity of DOX by embedding DOX inside human serum albumin (HSA). HSA is further fused by a molecular biology technique with a tumor-targeting agent, amino-terminal fragment of urokinase (ATF). ATF binds with a high affinity to urokinase receptor, which is a cell-surface receptor overexpressed in many types of tumors. The as-prepared macromolecule complex (ATF-HSA:DOX) was not as cytotoxic as free DOX to cells in vitro, and was mainly localized in cell cytosol in contrast to DOX that was localized in cell nuclei. However, in tumor-bearing mice, ATF-HSA:DOX was demonstrated to have an enhanced tumor-targeting and antitumor efficacy compared with free DOX. More importantly, histopathological examinations of the hearts from the mice treated with ATF-HSA:DOX showed a significantly reduced cardiotoxicity compared with hearts from mice treated with free DOX. These results demonstrate the feasibility of this approach in reducing the cardiotoxicity of DOX while strengthening its antitumor efficacy. Such a tumor-targeted albumin packaging strategy can also be applied to other antitumor drugs.