ABSTRACT
Radiologic screening of high-risk adults reduces lung-cancer-related mortality1,2; however, a small minority of eligible individuals undergo such screening in the United States3,4. The availability of blood-based tests could increase screening uptake. Here we introduce improvements to cancer personalized profiling by deep sequencing (CAPP-Seq)5, a method for the analysis of circulating tumour DNA (ctDNA), to better facilitate screening applications. We show that, although levels are very low in early-stage lung cancers, ctDNA is present prior to treatment in most patients and its presence is strongly prognostic. We also find that the majority of somatic mutations in the cell-free DNA (cfDNA) of patients with lung cancer and of risk-matched controls reflect clonal haematopoiesis and are non-recurrent. Compared with tumour-derived mutations, clonal haematopoiesis mutations occur on longer cfDNA fragments and lack mutational signatures that are associated with tobacco smoking. Integrating these findings with other molecular features, we develop and prospectively validate a machine-learning method termed 'lung cancer likelihood in plasma' (Lung-CLiP), which can robustly discriminate early-stage lung cancer patients from risk-matched controls. This approach achieves performance similar to that of tumour-informed ctDNA detection and enables tuning of assay specificity in order to facilitate distinct clinical applications. Our findings establish the potential of cfDNA for lung cancer screening and highlight the importance of risk-matching cases and controls in cfDNA-based screening studies.
Subject(s)
Circulating Tumor DNA/analysis , Circulating Tumor DNA/genetics , Early Detection of Cancer/methods , Genome, Human/genetics , Lung Neoplasms/diagnosis , Lung Neoplasms/genetics , Mutation , Cohort Studies , Female , Hematopoiesis/genetics , Humans , Lung/metabolism , Lung/pathology , Lung Neoplasms/blood , Lung Neoplasms/pathology , Male , Middle Aged , Reproducibility of ResultsABSTRACT
Fluorescence imaging is currently being actively developed for surgical guidance; however, it remains underutilized for diagnostic and endoscopic surveillance of incipient colorectal cancer in high-risk patients. Here we demonstrate the utility and potential for clinical translation of a fluorescently labeled cathepsin-activated chemical probe to highlight gastrointestinal lesions. This probe stays optically dark until it is activated by proteases produced by tumor-associated macrophages and accumulates within the lesions, enabling their detection using an endoscope outfitted with a fluorescence detector. We evaluated the probe in multiple murine models and a human-scale porcine model of gastrointestinal carcinogenesis. The probe provides fluorescence-guided surveillance of gastrointestinal lesions and augments histopathological analysis by highlighting areas of dysplasia as small as 400 µm, which were visibly discernible with significant tumor-to-background ratios, even in tissues with a background of severe inflammation and ulceration. Given these results, we anticipate that this probe will enable sensitive fluorescence-guided biopsies, even in the presence of highly inflamed colorectal tissue, which will improve early diagnosis to prevent gastrointestinal cancers.
Subject(s)
Early Detection of Cancer/methods , Endoscopy/methods , Precancerous Conditions/diagnosis , Animals , Colon/pathology , Colonic Neoplasms/pathology , Colorectal Neoplasms/pathology , Disease Models, Animal , Female , Fluorescence , Fluorescent Dyes , Gastrointestinal Neoplasms/pathology , Gastrointestinal Tract/pathology , Male , Mice , Mice, Inbred C57BL , Molecular Imaging/methods , Precancerous Conditions/pathology , Rats , Rats, Inbred Strains , Stomach Neoplasms/diagnosis , Stomach Neoplasms/prevention & control , SwineABSTRACT
Robust cytotoxic T cell infiltration has proven to be difficult to achieve in solid tumors. We set out to develop a flexible protocol to efficiently transfect tumor and stromal cells to produce immune-activating cytokines, and thus enhance T cell infiltration while debulking tumor mass. By combining ultrasound with tumor-targeted microbubbles, membrane pores are created and facilitate a controllable and local transfection. Here, we applied a substantially lower transmission frequency (250 kHz) than applied previously. The resulting microbubble oscillation was significantly enhanced, reaching an effective expansion ratio of 35 for a peak negative pressure of 500 kPa in vitro. Combining low-frequency ultrasound with tumor-targeted microbubbles and a DNA plasmid construct, 20% of tumor cells remained viable, and â¼20% of these remaining cells were transfected with a reporter gene both in vitro and in vivo. The majority of cells transfected in vivo were mucin 1+/CD45- tumor cells. Tumor and stromal cells were then transfected with plasmid DNA encoding IFN-ß, producing 150 pg/106 cells in vitro, a 150-fold increase compared to no-ultrasound or no-plasmid controls and a 50-fold increase compared to treatment with targeted microbubbles and ultrasound (without IFN-ß). This enhancement in secretion exceeds previously reported fourfold to fivefold increases with other in vitro treatments. Combined with intraperitoneal administration of checkpoint inhibition, a single application of IFN-ß plasmid transfection reduced tumor growth in vivo and recruited efficacious immune cells at both the local and distant tumor sites.
Subject(s)
Immunotherapy/methods , Interferon-beta/genetics , Neoplasms, Experimental/therapy , T-Lymphocytes/immunology , Transfection/methods , Ultrasonic Waves , Animals , Cell Line, Tumor , Cell Membrane/radiation effects , Cell Movement , Humans , Interferon-beta/metabolism , Mice , Microbubbles/therapeutic use , T-Lymphocytes/physiologyABSTRACT
Resistance to androgen deprivation therapy, or castration-resistant prostate cancer (CRPC), is often accompanied by metastasis and is currently the ultimate cause of prostate cancer-associated deaths in men. Recently, secondary hormonal therapies have led to an increase of neuroendocrine prostate cancer (NEPC), a highly aggressive variant of CRPC. Here, we identify that high levels of cell surface receptor Trop2 are predictive of recurrence of localized prostate cancer. Moreover, Trop2 is significantly elevated in CRPC and NEPC, drives prostate cancer growth, and induces neuroendocrine phenotype. Overexpression of Trop2 induces tumor growth and metastasis while loss of Trop2 suppresses these abilities in vivo. Trop2-driven NEPC displays a significant up-regulation of PARP1, and PARP inhibitors significantly delay tumor growth and metastatic colonization and reverse neuroendocrine features in Trop2-driven NEPC. Our findings establish Trop2 as a driver and therapeutic target for metastatic prostate cancer with neuroendocrine phenotype and suggest that high Trop2 levels could identify cancers that are sensitive to Trop2-targeting therapies and PARP1 inhibition.
Subject(s)
Antigens, Neoplasm/metabolism , Biomarkers, Tumor/metabolism , Bone Neoplasms/secondary , Carcinoma, Neuroendocrine/pathology , Cell Adhesion Molecules/metabolism , Gene Expression Regulation, Neoplastic , Poly (ADP-Ribose) Polymerase-1/metabolism , Prostatic Neoplasms, Castration-Resistant/pathology , Animals , Antigens, Neoplasm/genetics , Apoptosis , Biomarkers, Tumor/genetics , Bone Neoplasms/drug therapy , Bone Neoplasms/metabolism , Carcinoma, Neuroendocrine/drug therapy , Carcinoma, Neuroendocrine/metabolism , Cell Adhesion Molecules/genetics , Cell Movement , Cell Proliferation , Follow-Up Studies , Humans , Male , Mice , Mice, Inbred NOD , Mice, SCID , Neoplasm Invasiveness , Phenotype , Poly (ADP-Ribose) Polymerase-1/antagonists & inhibitors , Poly (ADP-Ribose) Polymerase-1/genetics , Poly(ADP-ribose) Polymerase Inhibitors/pharmacology , Prognosis , Prostatic Neoplasms, Castration-Resistant/drug therapy , Prostatic Neoplasms, Castration-Resistant/metabolism , Survival Rate , Tumor Cells, Cultured , Xenograft Model Antitumor AssaysABSTRACT
BACKGROUND: Liquid biopsy circulating tumor DNA (ctDNA) mutational analysis holds great promises for precision medicine targeted therapy and more effective cancer management. However, its wide adoption is hampered by high cost and long turnaround time of sequencing assays, or by inadequate analytical sensitivity of existing portable nucleic acid tests to mutant allelic fraction in ctDNA. METHODS: We developed a ctDNA Epidermal Growth Factor Receptor (EGFR) mutational assay using giant magnetoresistive (GMR) nanosensors. This assay was validated in 36 plasma samples of non-small cell lung cancer patients with known EGFR mutations. We assessed therapy response through follow-up blood draws, determined concordance between the GMR assay and radiographic response, and ascertained progression-free survival of patients. RESULTS: The GMR assay achieved analytical sensitivities of 0.01% mutant allelic fraction. In clinical samples, the assay had 87.5% sensitivity (95% CI = 64.0-97.8%) for Exon19 deletion and 90% sensitivity (95% CI = 69.9-98.2%) for L858R mutation with 100% specificity; our assay detected T790M resistance with 96.3% specificity (95% CI = 81.7-99.8%) with 100% sensitivity. After 2 weeks of therapy, 10 patients showed disappearance of ctDNA by GMR (predicted responders), whereas 3 patients did not (predicted nonresponders). These predictions were 100% concordant with radiographic response. Kaplan-Meier analysis showed responders had significantly (P < 0.0001) longer PFS compared to nonresponders (N/A vs. 12 weeks, respectively). CONCLUSIONS: The GMR assay has high diagnostic sensitivity and specificity and is well suited for detecting EGFR mutations at diagnosis and noninvasively monitoring treatment response at the point-of-care.
Subject(s)
Biosensing Techniques , Carcinoma, Non-Small-Cell Lung , Circulating Tumor DNA/genetics , DNA Mutational Analysis/methods , Drug Monitoring/methods , ErbB Receptors/genetics , Lung Neoplasms , Acrylamides/therapeutic use , Aged , Aniline Compounds/therapeutic use , Carcinoma, Non-Small-Cell Lung/diagnosis , Carcinoma, Non-Small-Cell Lung/drug therapy , Carcinoma, Non-Small-Cell Lung/genetics , Female , Humans , Liquid Biopsy , Lung Neoplasms/diagnosis , Lung Neoplasms/drug therapy , Lung Neoplasms/genetics , Male , Middle Aged , Mutation , Oligonucleotide Array Sequence Analysis , Protein Kinase Inhibitors/therapeutic use , Protein-Tyrosine Kinases/antagonists & inhibitorsABSTRACT
Surface-enhanced Raman spectroscopy (SERS) is a promising cellular identification and drug susceptibility testing platform, provided it can be performed in a controlled liquid environment that maintains cell viability. We investigate bacterial liquid-SERS, studying plasmonic and electrostatic interactions between gold nanorods and bacteria that enable uniformly enhanced SERS. We synthesize five nanorod sizes with longitudinal plasmon resonances ranging from 670 to 860 nm and characterize SERS signatures of Gram-negative Escherichia coli and Serratia marcescens and Gram-positive Staphylococcus aureus and Staphylococcus epidermidis bacteria in water. Varying the concentration of bacteria and nanorods, we achieve large-area SERS enhancement that is independent of nanorod resonance and bacteria type; however, bacteria with higher surface charge density exhibit significantly higher SERS signal. Using cryo-electron microscopy and zeta potential measurements, we show that the higher signal results from attraction between positively charged nanorods and negatively charged bacteria. Our robust liquid-SERS measurements provide a foundation for bacterial identification and drug testing in biological fluids.
Subject(s)
Mycobacterium tuberculosis , Spectrum Analysis, Raman , Cryoelectron Microscopy , Gold , Microbial Sensitivity Tests , Static ElectricityABSTRACT
Radiotheranostics, injectable radiopharmaceuticals with antitumour effects, have seen rapid development over the past decade. Although some formulations are already approved for human use, more radiopharmaceuticals will enter clinical practice in the next 5 years, potentially introducing new therapeutic choices for patients. Despite these advances, several challenges remain, including logistics, supply chain, regulatory issues, and education and training. By highlighting active developments in the field, this Review aims to alert practitioners to the value of radiotheranostics and to outline a roadmap for future development. Multidisciplinary approaches in clinical trial design and therapeutic administration will become essential to the continued progress of this evolving therapeutic approach.
Subject(s)
Biomedical Research/trends , Neoplasms/radiotherapy , Radiation Oncology/trends , Radiopharmaceuticals/administration & dosage , Theranostic Nanomedicine/trends , Animals , Diffusion of Innovation , Forecasting , Humans , Neoplasms/mortality , Neoplasms/pathology , Radiopharmaceuticals/adverse effects , Treatment OutcomeABSTRACT
V-domain Ig suppressor of T-cell activation (VISTA) is an immune checkpoint that affects the ability of T-cells to attack tumors. A FRET-based high throughput screening identified NSC622608 as the first small-molecule ligand for VISTA. Investigation of the interaction of NSC622608 with VISTA using STD NMR and molecular modeling enabled the identification of a potential binding site in VISTA for NSC622608. Screening NSC622608 against a library of single-point VISTA mutants revealed the key residues in VISTA interacting with NSC622608. Further structural optimization resulted in a lead with submicromolar VISTA binding affinity. The lead compound blocked VISTA signaling in vitro, enhanced T-cell proliferation, and restored T-cell activation in the presence of VISTA-expressing cancer cell lines. This work would enable future development of small molecules targeting VISTA as immunomodulators and imaging probes.
Subject(s)
B7 Antigens/antagonists & inhibitors , Drug Discovery , Immune Checkpoint Inhibitors/pharmacology , Small Molecule Libraries/pharmacology , B7 Antigens/immunology , Cell Line , Humans , Immune Checkpoint Inhibitors/chemistry , Ligands , Lymphocyte Activation/drug effects , Lymphocyte Activation/immunology , Molecular Structure , Small Molecule Libraries/chemistry , T-Lymphocytes/drug effects , T-Lymphocytes/immunologyABSTRACT
"Smart" biomaterials that are responsive to physiological or biochemical stimuli have found many biomedical applications for tissue engineering, therapeutics, and molecular imaging. In this work, we describe in situ polymerization of activatable biorthogonal small molecules in response to a reducing environment change in vivo. We designed a carbohydrate linker- and cyanobenzothiazole-cysteine condensation reaction-based small molecule scaffold that can undergo rapid condensation reaction upon physiochemical changes (such as a reducing environment) to form polymers (pseudopolysaccharide). The fluorescent and photoacoustic properties of a fluorophore-tagged condensation scaffold before and after the transformation have been examined with a dual-modality optical imaging method. These results confirmed the in situ polymerization of this probe after both local and systemic administration in living mice.
Subject(s)
Benzothiazoles/chemistry , Carbohydrates/chemistry , Cysteine/chemistry , Fluorescent Dyes/chemistry , Nitriles/chemistry , Optical Imaging , Polymerization , Animals , Cell Line, Tumor , Female , Fluorescent Dyes/chemical synthesis , Humans , Mice , Mice, Inbred BALB C , Mice, Nude , Molecular Structure , Neoplasms, Experimental/diagnostic imaging , Oxidation-ReductionABSTRACT
An antigen binding fragment (BFab) derived from a tumor-associated mucin 1-sialoglycotope antigen (CA6) targeting antibody (huDS6) was engineered. We synthesized a companion diagnostic positron emission tomography (PET) tracer by radiolabeling BFab with [64Cu] to measure CA6 expression on cancer tissues prior to anti-human CA6 (huDS6-DM4 antibody-drug conjugate) therapy for ovarian and breast cancer patients. After chemotherapy, the ovarian patient received PET scan with 18F-2-fluoro-2-deoxyglucose ([18F]FDG: 10 mCi), followed by [64Cu]-DOTA-BFab ([64Cu]BFab; 5.5 mCi) 1 week later for PET scanning of CA6 expression and subsequent surgery. The breast cancer patient was treated with chemotherapy before primary tumor resection and subsequent [18F]FDG-PET scan. 4 weeks later the patient received of [64Cu]BFab (11.7 mCi) for CA6 PET scan. Whole body [18F]FDG-PET of the breast cancer patient indicated FDG-avid tumor metastases to the liver, bilateral hila and thoracic spine, but no uptake was observed for the ovarian patient. Each patient was also imaged by PET/CT with [64Cu]BFab at 1 and 24 hours after tracer administration. The [64Cu]BFab tracer was well tolerated by both patients without adverse effects, and no significant tracer uptake was observed in both patients. Immunohistochemistry (IHC) data indicated CA6 expressions were weak to intermediate and matched with the [64Cu]BFab-PET signals.
Subject(s)
Breast Neoplasms , Immunoconjugates , Breast Neoplasms/diagnostic imaging , Breast Neoplasms/drug therapy , Female , Fluorodeoxyglucose F18 , Humans , Positron Emission Tomography Computed Tomography , Positron-Emission Tomography , RadiopharmaceuticalsABSTRACT
In recent years, there has been an unprecedented expansion in the field of nanomedicine with the development of new nanoparticles for the diagnosis and treatment of cancer. Nanoparticles have unique biological properties given their small size and large surface area-to-volume ratio, which allows them to bind, absorb, and carry compounds such as small molecule drugs, DNA, RNA, proteins, and probes with high efficiency. Their tunable size, shape, and surface characteristics also enable them to have high stability, high carrier capacity, the ability to incorporate both hydrophilic and hydrophobic substances and compatibility with different administration routes, thereby making them highly attractive in many aspects of oncology. This review article will discuss how nanoparticles are able to function as carriers for chemotherapeutic drugs to increase their therapeutic index; how they can function as therapeutic agents in photodynamic, gene, and thermal therapy; and how nanoparticles can be used as molecular imaging agents to detect and monitor cancer progression.
Subject(s)
Antineoplastic Agents/administration & dosage , Medical Oncology/trends , Nanomedicine/trends , Nanoparticles/therapeutic use , Neoplasms/drug therapy , Drug Carriers , Drug Delivery Systems , Humans , Tumor MicroenvironmentABSTRACT
6â³-[18 F]fluoromaltotriose is a positron emission tomography tracer that can differentiate between bacterial infection and inflammation in vivo. Bacteria-specific uptake of 6â³-[18 F]fluoromaltotriose is attributed to the targeting of maltodextrin transporter in bacteria that is absent in mammalian cells. Herein, we report a new synthesis of 6â³-[18 F]fluoromaltotriose as a key step for its clinical translation. In comparison with the previously reported synthesis, the new synthesis features unambiguous assignment of the fluorine-18 position on the maltotriose unit. The new method utilizes direct fluorination of 2â³,3â³,4â³-tri-O-acetyl-6â³-O-trifyl-α-D-glucopyranosyl-(1-4)-O-2',3',6'-tri-O-acetyl-α-D-glucopyranosyl-(1-4)-1,2,3,6-tetra-O-acetyl-D-glucopyranose followed by basic hydrolysis. Radiolabeling of the new maltotriose triflate precursor proceeds using a single HPLC purification step, which results in shorter reaction time in comparison with the previously reported synthesis. Successful synthesis of 6â³-[18 F]fluoromaltotriose has been achieved in 3.5 ± 0.3% radiochemical yield (decay corrected, n = 7) and radiochemical purity above 95%. The efficient radiosynthesis of 6â³-[18 F]fluoromaltotriose would be critical in advancing this positron emission tomography tracer into clinical trials for imaging bacterial infections.
Subject(s)
Bacterial Infections/congenital , Bacterial Infections/diagnostic imaging , Fluorine Radioisotopes , Positron-Emission Tomography , Trisaccharides/chemistry , Trisaccharides/chemical synthesis , Animals , Chemistry Techniques, Synthetic , HumansABSTRACT
Molecular imaging is revolutionizing the way we study the inner workings of the human body, diagnose diseases, approach drug design, and assess therapies. The field as a whole is making possible the visualization of complex biochemical processes involved in normal physiology and disease states, in real time, in living cells, tissues, and intact subjects. In this review, we focus specifically on molecular imaging of intact living subjects. We provide a basic primer for those who are new to molecular imaging, and a resource for those involved in the field. We begin by describing classical molecular imaging techniques together with their key strengths and limitations, after which we introduce some of the latest emerging imaging modalities. We provide an overview of the main classes of molecular imaging agents (i.e., small molecules, peptides, aptamers, engineered proteins, and nanoparticles) and cite examples of how molecular imaging is being applied in oncology, neuroscience, cardiology, gene therapy, cell tracking, and theranostics (therapy combined with diagnostics). A step-by-step guide to answering biological and/or clinical questions using the tools of molecular imaging is also provided. We conclude by discussing the grand challenges of the field, its future directions, and enormous potential for further impacting how we approach research and medicine.
Subject(s)
Molecular Imaging/methods , Animals , Diagnostic Imaging , Female , Humans , Magnetic Resonance Imaging/methods , Male , Mice , Molecular Imaging/instrumentation , Nanoparticles , Rats , Tomography, X-Ray Computed/methodsABSTRACT
Early and comprehensive endoscopic detection of colonic dysplasia - the most clinically significant precursor lesion to colorectal adenocarcinoma - provides an opportunity for timely, minimally-invasive intervention to prevent malignant transformation. Here, the development and evaluation of biodegradable near-infrared fluorescent silica nanoparticles (FSN) is described that have the potential to improve adenoma detection during fluorescence-assisted white-light colonoscopic surveillance in rodent and human-scale models of colorectal carcinogenesis. FSNs are biodegradable (t1/2 of 2.7 weeks), well-tolerated, and enable detection and delineation of adenomas as small as 0.5 mm2 with high tumor-to-background ratios. Furthermore, in the human-scale, APC 1311/+ porcine model, the clinical feasibility and benefit of using FSN-guided detection of colorectal adenomas using video-rate fluorescence-assisted white-light endoscopy is demonstrated. Since nanoparticles of similar size (e.g., 100-150-nm) or composition (i.e., silica, silica/gold hybrid) have already been successfully translated to the clinic, and, clinical fluorescent/white light endoscopy systems are becoming more readily available, there is a viable path towards clinical translation of the proposed strategy for early colorectal cancer detection and prevention in high-risk patients.
ABSTRACT
Poly(ADP ribose) polymerase (PARP) enzymes generate poly(ADP ribose) post-translational modifications on target proteins for an array of functions centering on DNA and cell stress. PARP isoforms 1 and 2 are critically charged with the surveillance of DNA integrity and are the first line guardians of the genome against DNA breaks. Here we present a novel probe ([18F]-SuPAR) for noninvasive imaging of PARP-1/2 activity using positron emission tomography (PET). [18F]-SuPAR is a radiofluorinated nicotinamide adenine dinucleotide (NAD) analog that can be recognized by PARP-1/2 and incorporated into the long branched polymers of poly(ADP ribose) (PAR). The measurement of PARP-1/2 activity was supported by a reduction of radiotracer uptake in vivo following PARP-1/2 inhibition with talazoparib treatment, a potent PARP inhibitor recently approved by FDA for treatment of breast cancer, as well as ex vivo colocalization of radiotracer analog and poly(ADP ribose). With [18F]-SuPAR, we were able to map the dose- and time-dependent activation of PARP-1/2 following radiation therapy in breast and cervical cancer xenograft mouse models. Tumor response to therapy was determined by [18F]-SuPAR PET within 8 h of administration of a single dose of radiation equivalent to one round of stereotactic ablative radiotherapy.
Subject(s)
DNA Damage , Fluorine Radioisotopes/administration & dosage , Poly(ADP-ribose) Polymerases/metabolism , Animals , Breast Neoplasms/diagnostic imaging , Female , Humans , NAD/metabolism , Positron-Emission Tomography , Receptors, Urokinase Plasminogen Activator/metabolism , Substrate Specificity , Uterine Cervical Neoplasms/diagnostic imaging , Xenograft Model Antitumor AssaysABSTRACT
Circulating tumor cells (CTCs) are established cancer biomarkers for the "liquid biopsy" of tumors. Molecular analysis of single CTCs, which recapitulate primary and metastatic tumor biology, remains challenging because current platforms have limited throughput, are expensive, and are not easily translatable to the clinic. Here, we report a massively parallel, multigene-profiling nanoplatform to compartmentalize and analyze hundreds of single CTCs. After high-efficiency magnetic collection of CTC from blood, a single-cell nanowell array performs CTC mutation profiling using modular gene panels. Using this approach, we demonstrated multigene expression profiling of individual CTCs from non-small-cell lung cancer (NSCLC) patients with remarkable sensitivity. Thus, we report a high-throughput, multiplexed strategy for single-cell mutation profiling of individual lung cancer CTCs toward minimally invasive cancer therapy prediction and disease monitoring.
Subject(s)
Biomarkers, Tumor/blood , Carcinoma, Non-Small-Cell Lung/blood , Lung Neoplasms/blood , Neoplastic Cells, Circulating , Adult , Aged , Carcinoma, Non-Small-Cell Lung/pathology , Cell Count , Female , Gene Expression Profiling , Gene Expression Regulation, Neoplastic , Humans , Leukocyte Common Antigens/blood , Lung Neoplasms/pathology , Male , Microfluidics , Middle Aged , Mutation , Nanotechnology , Reverse Transcriptase Polymerase Chain Reaction , Single-Cell AnalysisABSTRACT
BACKGROUND: Although most patients with PDAC experience distant failure after resection, a significant portion still present with local recurrence. Intraoperative fluorescent imaging can potentially facilitate the visualization of involved peritumoral LNs and guide the locoregional extent of nodal dissection. Here, the efficacy of targeted intraoperative fluorescent imaging was examined in the detection of metastatic lymph nodes (LNs) during resection of pancreatic ductal adenocarcinoma (PDAC). METHODS: A dose-escalation prospective study was performed to assess feasibility of tumor detection within peripancreatic LNs using cetuximab-IRDye800 in PDAC patients. Fluorescent imaging of dissected LNs was analyzed ex vivo macroscopically and microscopically and fluorescence was correlated with histopathology. RESULTS: A total of 144 LNs (72 in the low-dose and 72 in the high-dose cohort) were evaluated. Detection of metastatic LNs by fluorescence was better in the low-dose (50 mg) cohort, where sensitivity and specificity was 100% and 78% macroscopically, and 91% and 66% microscopically. More importantly, this method was able to detect occult foci of tumor (measuring < 5 mm) with a sensitivity of 88% (15/17 LNs). CONCLUSION: This study provides proof of concept that intraoperative fluorescent imaging with cetuximab-IRDye800 can facilitate the detection of peripancreatic lymph nodes often containing subclinical foci of disease.
Subject(s)
Carcinoma, Pancreatic Ductal/surgery , Intraoperative Care/methods , Lymph Nodes/pathology , Molecular Imaging , Optical Imaging , Pancreatectomy , Pancreatic Neoplasms/surgery , Carcinoma, Pancreatic Ductal/metabolism , Carcinoma, Pancreatic Ductal/secondary , Cetuximab/administration & dosage , ErbB Receptors/metabolism , Feasibility Studies , Fluorescent Dyes/administration & dosage , Humans , Indoles/administration & dosage , Lymph Node Excision , Lymph Nodes/metabolism , Lymph Nodes/surgery , Lymphatic Metastasis , Microscopy, Fluorescence , Pancreatic Neoplasms/metabolism , Pancreatic Neoplasms/pathology , Predictive Value of Tests , Prospective Studies , Spectroscopy, Near-Infrared , Treatment OutcomeABSTRACT
BACKGROUND: The cystine/glutamate antiporter (xc-) has been implicated in several neurological disorders and, specifically, in multiple sclerosis (MS) as a mediator of glutamate excitotoxicity and proinflammatory immune responses. We aimed to evaluate an xc-specific positron emission tomography (PET) radiotracer, (4S)-4-(3-[18F]fluoropropyl)-L-glutamate ([18F]FSPG), for its ability to allow non-invasive monitoring of xc- activity in a mouse model of MS. METHODS: Experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice by subcutaneous injection of myelin oligodendrocyte glycoprotein (MOG35-55) peptide in complete Freund's adjuvant (CFA) followed by pertussis toxin. Control mice received CFA emulsion and pertussis toxin without MOG peptide, while a separate cohort of naïve mice received no treatment. PET studies were performed to investigate the kinetics and distribution of [18F]FSPG in naïve, control, pre-symptomatic, and symptomatic EAE mice, compared to 18F-fluorodeoxyglucose ([18F]FDG). After final PET scans, each mouse was perfused and radioactivity in dissected tissues was measured using a gamma counter. Central nervous system (CNS) tissues were further analyzed using ex vivo autoradiography or western blot. [18F]FSPG uptake in human monocytes, and T cells pre- and post-activation was investigated in vitro. RESULTS: [18F]FSPG was found to be more sensitive than [18F]FDG at detecting pathological changes in the spinal cord and brain of EAE mice. Even before clinical signs of disease, a small but significant increase in [18F]FSPG signal was observed in the spinal cord of EAE mice compared to controls. This increase in PET signal became more pronounced in symptomatic EAE mice and was confirmed by ex vivo biodistribution and autoradiography. Likewise, in the brain of symptomatic EAE mice, [18F]FSPG uptake was significantly higher than controls, with the largest changes observed in the cerebellum. Western blot analyses of CNS tissues revealed a significant correlation between light chain of xc- (xCT) protein levels, the subunit of xc- credited with its transporter activity, and [18F]FSPG-PET signal. In vitro [18F]FSPG uptake studies suggest that both activated monocytes and T cells contribute to the observed in vivo PET signal. CONCLUSION: These data highlight the promise of [18F]FSPG-PET as a technique to provide insights into neuroimmune interactions in MS and the in vivo role of xc- in the development and progression of this disease, thus warranting further investigation.
Subject(s)
Amino Acid Transport Systems, Acidic/metabolism , Encephalomyelitis, Autoimmune, Experimental/diagnostic imaging , Encephalomyelitis, Autoimmune, Experimental/metabolism , Fluorine Radioisotopes/metabolism , Glutamates/metabolism , Positron-Emission Tomography/methods , Animals , Cells, Cultured , Fluorodeoxyglucose F18/metabolism , Humans , Leukocytes, Mononuclear/metabolism , Mice , Mice, Inbred C57BL , Multiple Sclerosis/diagnostic imaging , Multiple Sclerosis/metabolismABSTRACT
Raman microspectroscopy provides chemo-selective image contrast, sub-micrometer resolution, and multiplexing capabilities. However, it suffers from weak signals resulting in image-acquisition times of up to several hours. Surface-enhanced Raman scattering (SERS) can dramatically enhance signals of molecules in close vicinity of metallic surfaces and overcome this limitation. Multimodal, SERS-active nanoparticles are usually labeled with Raman marker molecules, limiting SERS to the coating material. In order to realize multimodal imaging while acquiring the rich endogenous vibronic information of the specimen, a core-shell particle based on "Nanorice", where a spindle-shaped iron oxide core is encapsulated by a closed gold shell, is developed. An ultrathin layer of silica prevents agglomeration and unwanted chemical interaction with the specimen. This approach provides Raman signal enhancement due to plasmon resonance effects of the shell while the optical absorption in the near-infrared spectral region provides contrast in photoacoustic tomography. Finally, T2-relaxation of a magnetic resonance imaging (MRI) experiment is altered by taking advantage of the iron oxide core. The feasibility for Raman imaging is evaluated by nearfield simulations and experimental studies on the primate cell line COS1. MRI and photoacoustics are demonstrated in agarose phantoms illustrating the promising translational nature of this strategy for clinical applications in radiology.
Subject(s)
Contrast Media/chemistry , Dust , Magnetic Resonance Imaging/methods , Nanoparticles/chemistry , Photoacoustic Techniques/methods , Spectrum Analysis, Raman , Animals , COS Cells , Chlorocebus aethiops , Computer Simulation , Nanoparticles/ultrastructure , Phantoms, ImagingABSTRACT
BACKGROUND: Cell-free DNA (cfDNA) diagnostics are emerging as a new paradigm of disease monitoring and therapy management. The clinical utility of these diagnostics is relatively limited by a low signal-to-noise ratio, such as with low allele frequency (AF) mutations in cancer. While enriching for rare alleles to increase their AF before sample analysis is one strategy that can greatly improve detection capability, current methods are limited in their generalizability, ease of use, and applicability to point mutations. METHODS: Leveraging the robust single-base-pair specificity and generalizability of the CRISPR associated protein 9 (Cas9) system, we developed a deactivated Cas9 (dCas9)-based method of minor-allele enrichment capable of efficient single-target and multiplexed enrichment. The dCas9 protein was complexed with single guide RNAs targeted to mutations of interest and incubated with cfDNA samples containing mutant strands at low abundance. Mutation-bound dCas9 complexes were isolated, dissociated, and the captured DNA purified for downstream use. RESULTS: Targeting the 3 most common epidermal growth factor receptor mutations (exon 19 deletion, T790M, L858R) found in non-small cell lung cancer (NSCLC), we achieved >20-fold increases in AF and detected mutations by use of qPCR at an AF of 0.1%. In a cohort of 18 NSCLC patient-derived cfDNA samples, our method enabled detection of 8 out of 13 mutations that were otherwise undetected by qPCR. CONCLUSIONS: The dCas9 method provides an important application of the CRISPR/Cas9 system outside the realm of genome editing and can provide a step forward for the detection capability of cfDNA diagnostics.