Fluorescence imaging is currently attracting much interest as a method for intraoperative tumor detection, but most current tracers lack tumor specificity. Therefore, this technique can be further ...improved by tumor-specific detection. With tumor-targeted antibodies bound to a radioactive label, tumor-specific SPECT or PET is feasible in the clinical setting. The aim of the present study was to apply antibody-based tumor detection to intraoperative optical imaging, using preclinical in vivo mouse models.
Anti-vascular endothelial growth factor (VEGF) antibody bevacizumab and anti-human epidermal growth factor receptor (HER) 2 antibody trastuzumab were labeled with the near-infrared (NIR) fluorescence dye IRDye 800CW. Tumor uptake of the fluorescent tracers and their (89)Zr-labeled radioactive counterparts for PET was determined in human xenograft-bearing athymic mice during 1 wk after tracer injection, followed by ex vivo biodistribution and pathologic examination. Intraoperative imaging of fluorescent VEGF- or HER2-positive tumor lesions was performed in subcutaneous tumors and in intraperitoneal dissemination tumor models.
Tumor-to-background ratios, with fluorescent imaging, were 1.93 ± 0.40 for bevacizumab and 2.92 ± 0.29 for trastuzumab on day 6 after tracer injection. Real-time intraoperative imaging detected tumor lesions at even the submillimeter level in intraperitoneal dissemination tumor models. These results were supported by standard histology, immunohistochemistry, and fluorescence microscopy analyses.
NIR fluorescence-labeled antibodies targeting VEGF or HER2 can be used for highly specific and sensitive detection of tumor lesions in vivo. These preclinical findings encourage future clinical studies with NIR fluorescence-labeled tumor-specific antibodies for intraoperative-guided surgery in cancer patients.
Iatrogenic injury of the ureters is a feared complication of abdominal surgery. Zwitterionic near-infrared fluorophores are molecules with geometrically-balanced, electrically-neutral surface charge, ...which leads to renal-exclusive clearance and ultralow non-specific background binding. Such molecules could solve the ureter mapping problem by providing real-time anatomic and functional imaging, even through intact peritoneum. Here we present the first-in-human experience of this chemical class, as well as the efficacy study in patients undergoing laparoscopic abdominopelvic surgery. The zwitterionic near-infrared fluorophore ZW800-1 is safe, has pharmacokinetic properties consistent with an ideal blood pool agent, and rapid elimination into urine after a single low-dose intravenous injection. Visualization of structure and function of the ureters starts within minutes after ZW800-1 injection and lasts several hours. Zwitterionic near-infrared fluorophores add value during laparoscopic abdominopelvic surgeries and could potentially decrease iatrogenic urethral injury. Moreover, ZW800-1 is engineered for one-step covalent conjugatability, creating possibilities for developing novel targeted ligands.
To provide proof of principle of safety, breast tumor-specific uptake, and positive tumor margin assessment of the systemically administered near-infrared fluorescent tracer bevacizumab-IRDye800CW ...targeting VEGF-A in patients with breast cancer.
Twenty patients with primary invasive breast cancer eligible for primary surgery received 4.5 mg bevacizumab-IRDye800CW as intravenous bolus injection. Safety aspects were assessed as well as tracer uptake and tumor delineation during surgery and
in surgical specimens using an optical imaging system.
multiplexed histopathology analyses were performed for evaluation of biodistribution of tracer uptake and coregistration of tumor tissue and healthy tissue.
None of the patients experienced adverse events. Tracer levels in primary tumor tissue were higher compared with those in the tumor margin (
< 0.05) and healthy tissue (
< 0.0001). VEGF-A tumor levels also correlated with tracer levels (
= 0.63,
< 0.0002). All but one tumor showed specific tracer uptake. Two of 20 surgically excised lumps contained microscopic positive margins detected
by fluorescent macro- and microscopy and confirmed at the cellular level.
Our study shows that systemic administration of the bevacizumab-IRDye800CW tracer is safe for breast cancer guidance and confirms tumor and tumor margin uptake as evaluated by a systematic validation methodology. The findings are a step toward a phase II dose-finding study aimed at
margin assessment and point to a novel drug assessment tool that provides a detailed picture of drug distribution in the tumor tissue.
.
Small and flat adenomas are known to carry a high miss-rate during standard white-light endoscopy. Increased detection rate may be achieved by molecular fluorescence endoscopy with targeted ...near-infrared (NIR) fluorescent tracers. The aim of this study was to validate vascular endothelial growth factor A (VEGF-A) and epidermal growth factor receptor (EGFR)-targeted fluorescent tracers during ex vivo colonoscopy with an NIR endoscopy platform.
VEGF-A and EGFR expression was determined by immunohistochemistry on a large subset of human colorectal tissue samples--48 sessile serrated adenomas/polyps, 70 sporadic high-grade dysplastic adenomas, and 19 hyperplastic polyps--and tissue derived from patients with Lynch syndrome--78 low-grade dysplastic adenomas, 57 high-grade dysplastic adenomas, and 31 colon cancer samples. To perform an ex vivo colonoscopy procedure, 14 mice with small intraperitoneal EGFR-positive HCT116(luc) tumors received intravenous bevacizumab-800CW (anti-VEGF-A), cetuximab-800CW (anti-EGFR), control tracer IgG-800CW, or sodium chloride. Three days later, 8 resected HCT116(luc) tumors (2-5 mm) were stitched into 1 freshly resected human colon specimen and followed by an ex vivo molecular fluorescence colonoscopy procedure.
Immunohistochemistry showed high VEGF-A expression in 79%-96% and high EGFR expression in 51%-69% of the colorectal lesions. Both targets were significantly overexpressed in the colorectal lesions, compared with the adjacent normal colon crypts. During ex vivo molecular fluorescence endoscopy, all tumors could clearly be delineated for both bevacizumab-800CW and cetuximab-800CW tracers. Specific tumor uptake was confirmed with fluorescent microscopy showing, respectively, stromal and cell membrane fluorescence.
VEGF-A is a promising target for molecular fluorescence endoscopy because it showed a high protein expression, especially in sessile serrated adenomas/polyps and Lynch syndrome. We demonstrated the feasibility to visualize small tumors in real time during colonoscopy using a NIR fluorescence endoscopy platform, providing the endoscopist a wide-field red-flag technique for adenoma detection. Clinical studies are currently being performed in order to provide in-human evaluation of our approach.
In solid tumors, angiogenesis occurs in the setting of a defective vasculature and impaired lymphatic drainage that is associated with increased vascular permeability and enhanced tumor permeability. ...These universal aspects of the tumor microenvironment can have a marked influence on intratumoral drug delivery that may often be underappreciated. In this study, we investigated the effect of blood vessel normalization in tumors by the antiangiogenic drug bevacizumab on antibody uptake by tumors. In mouse xenograft models of human ovarian and esophageal cancer (SKOV-3 and OE19), we evaluated antibody uptake in tumors by positron emission tomographic imaging 24 and 144 hours after injection of (89)Zr-trastuzumab (SKOV-3 and OE19), (89)Zr-bevacizumab (SKOV-3), or (89)Zr-IgG (SKOV-3) before or after treatment with bevacizumab. Intratumor distribution was assessed by fluorescence microscopy along with mean vessel density (MVD) and vessel normalization. Notably, bevacizumab treatment decreased tumor uptake and intratumoral accumulation compared with baseline in the tumor models relative to controls. Bevacizumab treatment also reduced MVD in tumors and increased vessel pericyte coverage. These findings are clinically important, suggesting caution in designing combinatorial trials with therapeutic antibodies due to a possible reduction in tumoral accumulation that may be caused by bevacizumab cotreatment.
To find new potentially therapeutic drugs against clear cell Renal Cell Carcinoma (ccRCC), within drugs currently prescribed for other diseases (drug repositioning), we previously searched for drugs ...which are expected to bring the gene expression of 500 + ccRCC samples from The Cancer Genome Atlas closer to that of healthy kidney tissue samples. An inherent limitation of this bulk RNA-seq data is that tumour samples consist of a varying mixture of cancerous and non-cancerous cells, which influences differential gene expression analyses. Here, we investigate whether the drug repositioning candidates are expected to target the genes dysregulated in ccRCC cells by studying the association with tumour purity. When all ccRCC samples are analysed together, the drug repositioning potential of identified drugs start decreasing above 80% estimated tumour purity. Because ccRCC is a highly vascular tumour, attributed to frequent loss of VHL function and subsequent activation of Hypoxia-Inducible Factor (HIF), we stratified the samples by observed activation of the HIF-pathway. After stratification, the association between estimated tumour purity and drug repositioning potential disappears for HIF-activated samples. This result suggests that the identified drug repositioning candidates specifically target the genes expressed by HIF-activated ccRCC tumour cells, instead of genes expressed by other cell types part of the tumour micro-environment.
Reversal of cancer gene expression is predictive of therapeutic potential and can be used to find new indications for existing drugs (drug repositioning). Gene expression reversal potential is ...currently calculated, in almost all studies, by pre-aggregating all tumour samples into a single group signature or a limited number of molecular subtype signatures. Here, we investigate whether drug repositioning based on individual tumour sample gene expression signatures outperforms the use of tumour group and subtype signatures. The tumour signatures were created using 534 tumour samples and 72 matched normal samples from 530 clear cell renal cell carcinoma (ccRCC) patients. More than 20,000 drug signatures were extracted from the CMAP and LINCS databases. We show that negative enrichment of individual tumour samples correlated (Spearman's rho = 0.15) much better with the amount of differentially expressed genes in drug signatures than with the tumour group signature (Rho = 0.08) and the 4 tumour subtype signatures (Rho 0.036-0.11). Targeted drugs used against ccRCC, such as sirolimus and temsirolimus, which could not be identified with the pre-aggregated tumour signatures could be recovered using individual sample analysis. Thus, drug repositioning can be personalized by taking into account the gene expression profile of the individual's tumour sample.
More than 50 monoclonal antibodies (mAbs), including several antibody-drug conjugates, are in advanced clinical development, forming an important part of the many molecularly targeted anticancer ...therapeutics currently in development. Drug development is a relatively slow and expensive process, limiting the number of drugs that can be brought into late-stage trials. Development decisions could benefit from quantitative biomarkers, enabling visualization of the tissue distribution of (potentially modified) therapeutic mAbs to confirm effective whole-body target expression, engagement, and modulation and to evaluate heterogeneity across lesions and patients. Such biomarkers may be realized with positron emission tomography imaging of radioactively labeled antibodies, a process called immunoPET. This approach could potentially increase the power and value of early trials by improving patient selection, optimizing dose and schedule, and rationalizing observed drug responses. In this review, we summarize the available literature and the status of clinical trials regarding the potential of immunoPET during early anticancer drug development.
Incomplete oncologic resections and damage to vital structures during colorectal cancer surgery increases morbidity and mortality. Moreover, neoadjuvant chemoradiotherapy has become the standard ...treatment modality for locally advanced rectal cancer, where subsequent downstaging can make identification of the primary tumor more challenging during surgery. Near-infrared (NIR) fluorescence imaging can aid surgeons by providing real-time visualization of tumors and vital structures during surgery.
We present the first-in-human clinical experience of a novel NIR fluorescent peptide, cRGD-ZW800-1, for the detection of colon cancer. cRGD-ZW800-1 was engineered to have an overall zwitterionic chemical structure and neutral charge to lower nonspecific uptake and thus background fluorescent signal. We performed a phase I study in 11 healthy volunteer as well as a phase II feasibility study in 12 patients undergoing an elective colon resection, assessing 0.005, 0.015, and 0.05 mg/kg cRGD-ZW800-1 for the intraoperative visualization of colon cancer.
cRGD-ZW800-1 appears safe, and exhibited rapid elimination into urine after a single low intravenous dose. Minimal invasive intraoperative visualization of colon cancer through full-thickness bowel wall was possible after an intravenous bolus injection of 0.05 mg/kg at least 2 hours prior to surgery. Longer intervals between injection and imaging improved the tumor-to-background ratio.
cRGD-ZW800-1 enabled fluorescence imaging of colon cancer in both open and minimal invasive surgeries. Further development of cRGD-ZW800-1 for widespread use in cancer surgery may be warranted given the ubiquitous overexpression of various integrins on different types of tumors and their vasculature.
PDF
