Anti-carcinoembryonic Antigen Antibody Research Articles

Large-area grown ultrathin molybdenum oxides for label-free sensitive biomarker detection.

The rise of two-dimensional (2D) materials has provided a confined geometry and yielded methods for guiding electrons at the nanoscale level. 2D material-enabled electronic devices can interact and transduce the subtle charge perturbation and permit significant advancement in molecule discrimination technology with high accuracy, sensitivity, and specificity, leaving a significant impact on disease diagnosis and health monitoring. However, high-performance biosensors with scalable fabrication ability and simple protocols have yet to be fully realized due to the challenges in wafer-scale 2D film synthesis and integration with electronics. Here, we propose a molybdenum oxide (MoOx)-interdigitated electrode (IDE)-based label-free biosensing chip, which stands out for its wafer-scale dimension, tunability, ease of integration and compatibility with the complementary metal-oxide-semiconductor (CMOS) fabrication. The device surface is biofunctionalized with monoclonal anti-carcinoembryonic antigen antibodies (anti-CEA) via the linkage agent (3-aminopropyl)triethoxysilane (APTES) for carcinoembryonic antigen (CEA) detection and is characterized step-by-step to reveal the working mechanism. A wide range and real-time response of the CEA concentration from 0.1 to 100 ng mL-1 and a low limit of detection (LOD) of 0.015 ng mL-1 were achieved, meeting the clinical requirements for cancer diagnosis and prognosis in serum. The MoOx-IDE biosensor also demonstrates strong surface affinity towards molecules and high selectivity using L-cysteine (L-Cys), glycine (Gly), glucose (Glu), bovine serum albumin (BSA), and immunoglobulin G (IgG). This study showcases a simple, scalable, and low-cost strategy to create a nanoelectronic biosensing platform to achieve high-performance cancer biomarker discrimination capabilities.

Improving Intracellular Delivery of an Antibody-Drug Conjugate Targeting Carcinoembryonic Antigen Increases Efficacy at Clinically Relevant Doses In Vivo.

Solid tumor antibody-drug conjugates (ADC) have experienced more clinical success in the last 5 years than the previous 18-year span since the first ADC approval in 2000. While recent advances in protein engineering, linker design, and payload variations have played a role in this success, high expression and readily internalized targets have also been crucial to solid tumor therapy. However, these factors are also paradoxically connected to poor tissue penetration and lower efficacy. Previous work shows that potent ADCs can benefit from slower internalization under subsaturating doses to improve tissue penetration and increase tumor response. In contrast, faster internalization is predicted to increase efficacy under higher, tumor saturating doses. In this work, the intracellular delivery of SN-38 conjugated to an anti-carcinoembryonic antigen (anti-CEA) antibody (Ab) is increased by coadministering a noncompeting (cross-linking) anti-CEA Ab to improve efficacy in a colorectal carcinoma animal model. The SN-38 payload enables broad tumor saturation with clinically-tolerable doses, and under these saturating conditions, using a second CEA receptor cross-linking Ab yields faster internalization, which increases tumor killing efficacy. Our spheroid results show indirect bystander killing can also occur, but the more efficient direct cell killing from targeted intracellular payload release drives a greater tumor response. These results provide a strategy to increase therapeutic effectiveness with improved intracellular delivery under tumor saturating doses with the potential to expand the ADC target repertoire.

Biocatalytic Buoyancy-Driven Nanobots for Autonomous Cell Recognition and Enrichment

HighlightsA self-propelled, biocatalytic buoyancy-driven metal–organic framework (MOF) nanobot is developed.The anti-carcinoembryonic antigen antibody functionalized MOF nanobot demonstrates directional vertical motion to “find-and-fetch” cancer cells from mixed cell population.The captured cells can be recovered with full metabolic potential.

Humanized Anti-Carcinoembryonic Antigen Antibodies Brightly Target and Label Gastric Cancer in Orthotopic Mouse Models

IntroductionGastric cancer poses a major therapeutic challenge. Improved visualization of tumor margins at the time of gastrectomy with fluorescent tumor-specific antibodies could improve outcomes. The present report demonstrates the potential of targeting gastric cancer with a humanized anti-carcinoembryonic antigen (CEA) antibody in orthotopic mouse models. MethodsMKN45 cells were injected subcutaneously into nude mice to establish xenograft models. Tumor fragments collected from subcutaneous models were then implanted into the greater curvature of the stomach to establish orthotopic models. For tumor labeling, a humanized anti-CEA antibody (M5A) and IgG as a control, were conjugated with the near-infrared dye IRDye800CW. Time (24-72 h) and dose (50-100 μg) response curves were performed in subcutaneous models. Orthotopic models received 50 μg of M5A-IR800 or 50 μg IgG-IR800 as a control and were imaged after 72 h. Fluorescence imaging was performed on the mice using the LI-COR Pearl Imaging System. ResultsIn subcutaneous models, tumor to background ratios (TBRs) reached 8.85 at 72 h. Median TBRs of orthotopic model primary tumors were 6.25 (interquartile range [IQR] 6.03-7.12) for M5A-IR800 compared to 0.42 (IQR 0.38-0.54) for control. Abdominal wall metastasis median TBRs were 13.52 (IQR 12.79-13.76) for M5A-IR800 and 3.19 (IQR 2.65-3.73) for the control. Immunohistochemistry confirmed CEA expression within tumors. ConclusionsHumanized anti-CEA antibodies conjugated to near-infrared dyes provide specific labeling of gastric cancers in mouse models. Orthotopic models demonstrated bright and specific labeling with TBRs greater than ten times that of control. This tumor-specific fluorescent antibody is a promising potential clinical tool for improving visualization of gastric cancer margins at time of surgical resection.

Colorimetric immunoassay of carcinoembryonic antigen based on the glucose oxidase/MnO2 nanosheet cascade reaction with self-supplying oxygen.

The detection of carcinoembryonic antigen (CEA) has profound implications in cancer diagnostics and therapeutic monitoring. In this work, we developed a colorimetric immunoassay for the detection of CEA. This assay involves the utilization of zinc(II)-based coordination polymers (ZnCPs) as a host for integrating glucose oxidase (GOx) and anti-carcinoembryonic antigen antibody (anti-CEA), which results in the formation of a detection antibody (anti-CEA/GOx@ZnCPs). The adaptable inclusion properties of ZnCPs enable the preservation of the original catalytic behavior of GOx and antigen capture ability of anti-CEA. Consequently, the anti-CEA/GOx@ZnCPs can act as a detection antibody to facilitate the development of an immunoassay. The combination of anti-CEA/GOx@ZnCPs in the immunoassay triggers a cascade reaction involving GOx and MnO2 nanosheets, leading to the generation of an amplified colorimetric signal through self-supplying oxygen. This colorimetric immunoassay exhibits a linear response ranging from 2 to 180 ng mL-1 CEA and has a detection limit of 50 pg mL-1. The practicality of this colorimetric immunoassay in biological matrices was demonstrated by the successful determination of CEA in serum samples with good recovery and precision. We believe that this study will pave the way to rationally design multifunctional CP-based composites for a wide range of applications in bioanalysis.

Proof of concept of improved fluorescence-guided surgery of colon cancer liver metastasis using color-coded imaging of a tumor-labeling fluorescent antibody and indocyanine green restricted to the adjacent liver segment

BackgroundIndocyanine green has been used for fluorescence-guided surgery of liver metastasis and labeling of liver segments. However, indocyanine green is nonspecific, and indocyanine green labeling does not always clearly outline tumor margins. In addition, it is difficult to distinguish between a tumor and its adjacent liver segment colored with indocyanine green alone. In the present study, we performed fluorescence-guided surgery in an orthotopic colon-cancer liver metastasis mouse model by labeling the metastatic liver tumor with an anti-carcinoembryonic antigen fluorescent antibody and with indocyanine green restricted to the adjacent liver segment. MethodsA liver metastasis model was established with human LS174T colon cancer tumor fragments. To label the tumor, mice received SGM-101, an anti-carcinoembryonic antigen antibody conjugated to a near-infrared fluorophore (700 nm), currently in clinical trials, 3 days before surgery. Indocyanine green (800 nm) was injected after ligation of the tumor-bearing Glissonean pedicle with fluorescence labeling restricted to the liver segment adjacent to the tumor. Bright-light surgery and fluorescence-guided surgery were performed to resect the liver metastasis. To assess recurrence, mice underwent necropsy 3 weeks after surgery and the tumor was weighed. ResultsFluorescence-guided anatomic left lateral lobectomy and fluorescence-guided partial liver resection were both performed with color-coded double labeled imaging. Tumor weight 3 weeks after surgery was significantly lower with fluorescence-guided surgery compared to bright-light surgery (38 ± 57 mg vs 836 ± 668 mg, P = .011) for partial liver resection. ConclusionThe present study provides a proof-of-concept that color-coded and double labeling of the tumor and adjacent liver segment has the potential to improve liver metastasectomy.

Multimodal CEA-targeted fluorescence and radioguided cytoreductive surgery for peritoneal metastases of colorectal origin

In patients with colorectal peritoneal metastases scheduled for cytoreductive surgery, accurate preoperative estimation of tumor burden and subsequent intraoperative detection of all tumor deposits remains challenging. In this study (ClinicalTrials.gov NCT03699332) we describe the results of a phase I clinical trial evaluating [111In]In-DOTA-labetuzumab-IRDye800CW, a dual-labeled anti-carcinoembryonic antigen (anti-CEA) antibody conjugate that enables both preoperative imaging and intraoperative radioguidance and fluorescence imaging. Primary study outcomes are safety and feasibility of this multimodal imaging approach. Secondary outcomes are determination of the optimal dose, correlation between tracer uptake and histopathology and effects on clinical strategy. Administration of [111In]In-DOTA-labetuzumab-IRDye800CW is well-tolerated and enables sensitive pre- and intraoperative imaging in patients who receive 10 or 50 mg of the tracer. Preoperative imaging revealed previously undetected lymph node metastases in one patient, and intraoperative fluorescence imaging revealed four previously undetected metastases in two patients. Alteration of clinical strategy based on multimodal imaging occurred in three patients. Thus, multimodal image-guided surgery after administration of this dual-labeled tracer is a promising approach that may aid in decision making before and during cytoreductive surgical procedures.

Targeted Delivery of Endosomal Escape Peptides to Enhance Immunotoxin Potency and Anti-cancer Efficacy.

This work describes use of anti-carcinoembryonic antigen antibodies (10H6, T84.66) for targeted delivery of an endosomal escape peptide (H6CM18) and gelonin, a type I ribosome inactivating protein. The viability of colorectal cancer cells (LS174T, LoVo) was assessed following treatment with gelonin or gelonin immunotoxins, with or without co-treatment with T84.66-H6CM18. Fluorescent microscopy was used to visualize the escape of immunoconjugates from endosomes of treated cells, and efficacy and toxicity were assessed in vivo in xenograft tumor-bearing mice following single- and multiple-dose regimens. Application of 25pM T84.66-H6CM18 combined with T84.66-gelonin increased gelonin potency by ~ 1,000-fold and by ~ 6,000-fold in LS174T and LoVo cells. Intravenous 10H6-gelonin at 1.0mg/kg was well tolerated by LS174T tumor-bearing mice, while 10 and 25mg/kg doses led to signs of toxicity. Single-dose administration of PBS, gelonin conjugated to T84.66 or 10H6, T84.66-H6CM18, or gelonin immunotoxins co-administered with T84.66-H6CM18 were evaluated. The combinations of T84.66-gelonin + 1.0mg/kg T84.66-H6CM18 and 10H6-gelonin + 0.1mg/kg T84.66-H6CM18 led to significant delays in LS174T growth. Use of a multiple-dose regimen allowed further anti-tumor effects, significantly extending median survival time by 33% and by 69%, for mice receiving 1mg/kg 10H6-gelonin + 0.1mg/kg T84.66-H6CM18 (p = 0.0072) and 1mg/kg 10H6-gelonin + 1mg/kg T84.66-H6CM18 (p = 0.0017). Combined administration of gelonin immunoconjugates with antibody-targeted endosomal escape peptides increased the delivery of gelonin to the cytoplasm of targeted cells, increased gelonin cell killing in vitro by 1,000-6,000 fold, and significantly increased in vivo efficacy.

Spectrally Distinct Double Labeling of Colon-Cancer Liver Metastases and Adjacent Liver Segment with a Near-Infrared-labeled Anti-Carcinoembryonic Antigen (CEA) Antibody and Indocyanine Green in an Orthotopic Mouse Model

Spectrally Distinct Double Labeling of Colon-Cancer Liver Metastases and Adjacent Liver Segment with a Near-Infrared-labeled Anti-Carcinoembryonic Antigen (CEA) Antibody and Indocyanine Green in an Orthotopic Mouse Model

Cucurbituril-Ferrocene: Host-Guest Based Pretargeted Positron Emission Tomography in a Xenograft Model.

Pretargeted positron emission tomography is a macromolecule-driven nuclear medicine technique that involves targeting a preadministered antigen target-bound macromolecule with a radioligand in vivo, aiming to minimize the overall radiation dose. This study investigates the use of antibody based host-guest chemistry methodology for pretargeted positron emission tomography. We hypothesize that the novel pretargeting approach reported here overcomes the challenges the current pretargeting platforms have with the in vivo stability and modularity of the pretargeting components. A cucurbit[7]uril host molecule modified, anti-carcinoembryonic antigen antibody (M5A; CB7-M5A) and a 68Ga-radiolabeled ferrocene guest radioligand ([68Ga]Ga-NOTA-PEG3-NMe2-Fc) were studied as potential host-guest chemistry pretargeting agents for positron emission tomography in BxPC3 xenografted nude mice. The viability of the platform was studied via in vivo biodistribution and positron emission tomography. Tumor uptake of [68Ga]Ga-NOTA-PEG3-NMe2-Fc was significantly higher in mice which received CB7-M5A prior to the radioligand injection (pretargeted) (3.3 ± 0.7%ID/g) compared to mice which only received the radioligand (nonpretargeted) (0.2 ± 0.1%ID/g).

Biotin-streptavidin-guided two-step pretargeting approach using PLGA for molecular ultrasound imaging and chemotherapy for ovarian cancer.

BackgroundOvarian cancer seriously threatens the lives and health of women, and early diagnosis and treatment are still challenging. Pre-targeting is a promising strategy to improve the treatment efficacy of ovarian cancer and the results of ultrasound imaging.PurposeTo explore the effects of a pre-targeting strategy using streptavidin (SA) and paclitaxel (PTX)-loaded phase-shifting poly lactic-co-glycolic acid (PLGA) nanoparticles with perfluoro-n-pentane (PTX-PLGA-SA/PFPs) on the treatment and ultrasound imaging of ovarian cancer.MethodsPTX-PLGA/PFPs were prepared with a single emulsion (O/W) solvent evaporation method and SA was attached using carbodiimide. The encapsulation efficiency of PTX and the release characteristics were assessed with high performance liquid chromatography. The phase-change characteristics of the PTX-PLGA-SA/PFPs were investigated. The anti-carcinoembryonic antigen (CEA) antibody (Ab) was covalently attached to PTX-PLGA/PFPs via carbodiimide to create PTX-PLGA-Ab/PFPs. The targeting efficiency of the nanoparticles and the viability of ovarian cancer SKOV3 cells were evaluated in each group using a microscope, flow cytometry, and cell counting kit 8 assays.ResultsTHE PTX-PLGA-SA/PFPs were spheres with a size of 383.0 ± 75.59 nm. The encapsulation efficiency and loading capability of the nanoparticles for PTX were 71.56 ± 6.51% and 6.57 ± 0.61%, respectively. PTX was burst-released up to 70% in 2–3 d. When irradiated at 7.5 W for 3 min, the PTX-PLGA-SA/PFPs visibly enhanced the ultrasonography images (P < 0.05). At temperatures of 45°C and 60°C the nanoparticles phase-shifted into micro-bubbles and the sizes increased. The binding efficiencies of SA and Ab to the PTX-PLGA/PFPs were 97.16 ± 1.20% and 92.74 ± 5.75%, respectively. Pre-targeting resulted in a high binding efficacy and killing effect on SKOV3 cells (P < 0.05).ConclusionsThe two-step pre-targeting process can significantly enhance the targeting ability of PTX-loaded PLGA nanoparticles for ovarian cancer cells and substantially improve the therapeutic efficacy. This technique provides a new method for ultrasonic imaging and precise chemotherapy for ovarian cancer.

Ex Vivo Assessment of Tumor-Targeting Fluorescent Tracers for Image-Guided Surgery.

Image-guided surgery can aid in achieving complete tumor resection. The development and assessment of tumor-targeted imaging probes for near-infrared fluorescence image-guided surgery relies mainly on preclinical models, but the translation to clinical use remains challenging. In the current study, we introduce and evaluate the application of a dual-labelled tumor-targeting antibody for ex vivo incubation of freshly resected human tumor specimens and assessed the tumor-to-adjacent tissue ratio of the detectable signals. Immediately after surgical resection, peritoneal tumors of colorectal origin were placed in cold medium. Subsequently, tumors were incubated with 111In-DOTA-hMN-14-IRDye800CW, an anti-carcinoembryonic antigen (CEA) antibody with a fluorescent and radioactive label. Tumors were then washed, fixed, and analyzed for the presence and location of tumor cells, CEA expression, fluorescence, and radioactivity. Twenty-six of 29 tumor samples obtained from 10 patients contained malignant cells. Overall, fluorescence intensity was higher in tumor areas compared to adjacent non-tumor tissue parts (p < 0.001). The average fluorescence tumor-to-background ratio was 11.8 ± 9.1:1. A similar ratio was found in the autoradiographic analyses. Incubation with a non-specific control antibody confirmed that tumor targeting of our tracer was CEA-specific. Our results demonstrate the feasibility of this tracer for multimodal image-guided surgery. Furthermore, this ex vivo incubation method may help to bridge the gap between preclinical research and clinical application of new agents for radioactive, near infrared fluorescence or multimodal imaging studies.

A Colorimetric Immunoassay Based on Coordination Polymer Composite for the Detection of Carcinoembryonic Antigen.

Coordination polymers (CPs) as fascinating materials have been explored in a number of fields due to their diverse properties. In this work, we demonstrate the feasibility of CPs in the facile fabrication of multifunctional composites for establishing an immunoassay. To this end, a zinc(II)-based CP (ZnCP) with adenine as a bridge ligand was employed to integrate with alkaline phosphatase (ALP) and anticarcinoembryonic antigen (anti-CEA) antibody, which produces ALP/anti-CEA@ZnCPs. Benefiting from the adaptive inclusion property of ZnCPs, the integrated ALP and anti-CEA can maintain their original catalytic activity and capture ability to target antigen, respectively. This allows the ALP/anti-CEA@ZnCPs to be a detection antibody for performing an immunoassay. Meanwhile, ZnCP as a host can effectively protect the loaded ALP and anti-CEA against harsh environments. On this basis, by using iron(II)-phenanthroline complex as a signal amplifier, a colorimetric immunoassay for CEA detection was developed, and a low detection limit of 21.1 pg/mL has been achieved. This immunoassay was successfully applied to determine CEA levels in serum samples with good recovery and precision. We believe that this study can not only provide a new method for CEA detection but also open up a new way for the rational design and fabrication of multifunctional composites.

Improved antibody-guided surgery with a near-infrared dye on a pegylated linker for CEA-positive tumors.

.Real-time intraoperative image-guided cancer surgery promises to improve oncologic outcomes. Tumor-specific antibodies conjugated with near-infrared (NIR) fluorophores have demonstrated the potential to enhance visualization of solid tumor margins and metastatic disease; however, multiple challenges remain, including improvement in probe development for clinical utility. We have developed an NIR-IR800 dye on a PEGylated linker (sidewinder) conjugated to the humanized anti-carcinoembryonic antigen (CEA) antibody (M5A) with extended in vivo serum and tumor persistence. The anti-CEA M5A-sidewinder has a high dye-to-antibody ratio (average of 7 per antibody) that allows, in an orthotopic implanted human pancreatic cancer mouse model increased tumor fluorescence, higher tumor-to-background ratio and extends the surgical scheduling window compared to current antibody dye conjugates. These preclinical results demonstrate the potential of this probe for fluorescence-guided surgery of CEA-positive gastrointestinal cancers.

Image-Guided Surgery in Patients with Pancreatic Cancer: First Results of a Clinical Trial Using SGM-101, a Novel Carcinoembryonic Antigen-Targeting, Near-Infrared Fluorescent Agent

BackgroundNear-infrared (NIR) fluorescence is a promising novel imaging technique that can aid in intraoperative demarcation of pancreatic cancer (PDAC) and thus increase radical resection rates. This study investigated SGM-101, a novel, fluorescent-labeled anti-carcinoembryonic antigen (CEA) antibody. The phase 1 study aimed to assess the tolerability and feasibility of intraoperative fluorescence tumor imaging using SGM-101 in patients undergoing a surgical exploration for PDAC.MethodsAt least 48 h before undergoing surgery for PDAC, 12 patients were injected intravenously with 5, 7.5, or 10 mg of SGM-101. Tolerability assessments were performed at regular intervals after dosing. The surgical field was imaged using the Quest NIR imaging system. Concordance between fluorescence and tumor presence on histopathology was studied.ResultsIn this study, SGM-101 specifically accumulated in CEA-expressing primary tumors and peritoneal and liver metastases, allowing real-time intraoperative fluorescence imaging. The mean tumor-to-background ratio (TBR) was 1.6 for primary tumors and 1.7 for metastatic lesions. One false-positive lesion was detected (CEA-expressing intraductal papillary mucinous neoplasm). False-negativity was seen twice as a consequence of overlying blood or tissue that blocked the fluorescent signal.ConclusionThe use of a fluorescent-labeled anti-CEA antibody was safe and feasible for the intraoperative detection of both primary PDAC and metastases. These results warrant further research to determine the impact of this technique on clinical decision making and overall survival.

Tumor-Specific Labeling of Pancreatic Cancer Using a Humanized Anti-CEA Antibody Conjugated to a Near-Infrared Fluorophore.

Development of a humanized fluorophore-conjugated antibody that can improve contrast for fluorescence-guided oncologic surgeries. BxPC-3-GFP pancreatic cancer cells were injected into flanks of nude mice. Fragments of subcutaneous tumors were grafted onto the pancreatic tail of recipient mice to create orthotopic xenograft models of pancreatic cancer. After tumors developed for 4weeks, a humanized anti-carcinoembryonic antigen antibody conjugated to an 800nm near-infrared fluorescent dye (hM5A-IR800) was injected intravenously. Mice were imaged at 6, 12, 24, 48, and 72h after injection. Fluorescence imaging showed that hM5A-IR800 specifically localized to BxPC-3 human pancreatic cancer cells. The fluorescent probe localized to cell surfaces in vitro and specifically co-localized with green fluorescent protein-labeled tumors in an orthotopic pancreatic xenograft model in vivo. Serial imaging at specific time points showed peak signal intensity of the orthotopic pancreatic tumor at 48h; this time point corresponded with a maximal tumor-to-background ratio (TBR) of 16.6 at 48h. hM5A-IR800 was successfully able to specifically label orthotopic pancreatic tumors in situ. The longer wavelength allowed deeper tissue penetration, particularly in tumor areas covered by normal pancreatic parenchyma. The probe had expected kinetics for an antibody-fluorophore conjugate, with the peak signal intensity reached at 48h. A clear tumor signal was observed with a TBR>5 at all time points, with high contrast (TBR of 16.6) at 48h. hM5A-IR800 demonstrated excellent tumor localization and a very bright signal. It is a promising agent for future clinical fluorescence-guided surgery applications.

Near-infrared–conjugated humanized anti-carcinoembryonic antigen antibody targets colon cancer in an orthotopic nude-mouse model

BackgroundThe success of a curative surgery for cancer is dependent on the complete removal of all cancer cells. Tumor visualization by the surgeon can be enhanced through fluorescent-antibody targeting. To further develop such technology, we selected humanized anti-carcinoembryonic antigen (CEA) conjugated to a near-infrared dye to target orthotopically-implanted human colon cancer in nude mice. Materials and methodsThe HT-29 human colon cancer cell line was grown in culture and subcutaneously injected in mice. After 3 wk of growth, tumors were resected and cut into 2 mm3 fragments that were sutured to the cecum of five additional nude mice for orthotopic implantation. The tumors were allowed to grow for 4 wk at which point 3 had successful orthotopic tumor growth and were selected for injection of the humanized anti-CEA antibody conjugated to the near-infrared dye IRDye800CW (anti-CEA-IRDye800CW). The antibody-dye conjugate (75 μg) was administered via tail vein injection. Images were obtained with the Pearl Trilogy Small Animal Imaging System with both 700 and 800 nm channels and evaluated using Image Studio. ResultsLaparotomy was performed 24 h after labeling the tumors. When imaged through the 800 nm channel, the tumors were observed to be strongly labeled with anti-CEA-IRDye800. At 48 h, laparotomy was repeated which again demonstrated strong labeling of the tumors through the 800 nm channel, but with a lower absolute intensity (in relative units), than at 24 h. ConclusionsHumanized anti-CEA-IRDye800CW can rapidly and effectively label CEA-expressing human colon cancer in an orthotopic nude mouse model. Given the ability of this technology to target and label tumors with great specificity, the anti-CEA-IRDye800CW is currently being developed for clinical use in fluorescence-guided surgery.

Significant Therapeutic Efficacy with Combined Radioimmunotherapy and Cetuximab in Preclinical Models of Colorectal Cancer.

Despite extensive efforts to improve the clinical management of patients with colorectal cancer, approved treatments for advanced disease offer limited survival benefit. Therefore, the identification of novel treatment strategies is essential. We evaluated the preclinical efficacy of combination radioimmunotherapy, using a humanized (131)I-labeled anti-carcinoembryonic antigen antibody ((131)I-huA5B7), with cetuximab in colorectal cancer (CRC). Three human CRC cell lines--SW1222, LoVo, and LS174T--were used to generate subcutaneous xenografts, and stably luciferase-transfected SW1222 cells were used to establish a model of hepatic metastases in immunocompromised mice. Imaging and biodistribution studies were conducted to confirm the selective tumor localization of (131)I-huA5B7. Efficacy was evaluated on the basis of tumor growth delay and survival, along with markers of DNA damage response, cell cycle, proliferation, and apoptosis. Selective tumor targeting was achieved with (131)I-huA5B7 alone or in combination with cetuximab without observable toxicity. Compared with monotherapy, combining cetuximab with radioimmunotherapy significantly and synergistically reduced tumor growth and prolonged survival of mice in 2 of the subcutaneous and in the metastatic tumor model. Evidence of DNA damage, G2/M arrest, significantly decreased proliferation, and increased apoptosis were observed with radioimmunotherapy and the combination therapy. However, a significant decrease in DNA-protein kinase expression with the combination regimen suggests that the addition of cetuximab suppressed DNA repair. Our results demonstrate enhanced therapeutic efficacy with the combination of cetuximab and radioimmunotherapy in CRC, which could potentially translate into successful clinical outcomes. This strategy could improve the treatment of residual disease postoperatively and ultimately prevent or delay recurrence. Furthermore, other carcinoembryonic antigen-expressing malignancies could also benefit from this approach.

Texture analysis of (125)I-A5B7 anti-CEA antibody SPECT differentiates metastatic colorectal cancer model phenotypes and anti-vascular therapy response.

Background:We aimed to test the ability of texture analysis to differentiate the spatial heterogeneity of 125I-A5B7 anti-carcinoembryonic antigen antibody distribution by nano-single photon emission computed tomography (SPECT) in well-differentiated (SW1222) and poorly differentiated (LS174T) hepatic metastatic colorectal cancer models before and after combretastatin A1 di-phosphate anti-vascular therapy.Methods:Nano-SPECT imaging was performed following tail vein injection of 20 MBq 125I-A5B7 in control CD1 nude mice (LS174T, n=3 and SW1222, n=4), and CA1P-treated mice (LS174T, n=3; SW1222, n=4) with liver metastases. Grey-level co-occurrence matrix textural features (uniformity, homogeneity, entropy and contrast) were calculated in up to three liver metastases in 14 mice from control and treatment groups.Results:Before treatment, the LS174T metastases (n=7) were more heterogeneous than SW1222 metastases (n=12) (uniformity, P=0.028; homogeneity, P=0.01; contrast, P=0.045). Following CA1P, LS174T metastases (n=8) showed less heterogeneity than untreated LS174T controls (uniformity, P=0.021; entropy, P=0.006). Combretastatin A1 di-phosphate-treated SW1222 metastases (n=11) showed no difference in texture features compared with controls (all P>0.05).Conclusions:Supporting the potential for novel imaging biomarkers, texture analysis of 125I-A5B7 SPECT shows differences in spatial heterogeneity of antibody distribution between well-differentiated (SW1222) and poorly differentiated (LS174T) liver metastases before treatment. Following anti-vascular treatment, LS174T metastases, but not SW1222 metastases, were less heterogeneous.

Retraction: “Radioimmunotherapy of small‐volume disease of metastatic colorectal cancer: Results of a phase II trial with the iodine‐131–labeled humanized anti–carcinoembryonic antigen antibody hMN‐14,”

Retraction: “Radioimmunotherapy of small‐volume disease of metastatic colorectal cancer: results of a phase II trial with the iodine‐131–labeled humanized anti–carcinoembryonic antigen antibody hMN‐14,” by Behr TM, Liersch T, Greiner‐Bechert L, Griesinger F, Béhé M, Markus PM, Gratz S, Angerstein C, Brittinger G, Becker H, Goldenberg DM, Becker W.1The above article, published online on February 12, 2002, in Wiley Online Library (wileyonlinelibrary.com), has been retracted by agreement amongst the authors, the journal Editor‐in‐Chief, Fadlo R. Khuri, Wiley Periodicals, Inc., and the American Cancer Society.The article was submitted for publication by the corresponding author, Thomas M. Behr, on the assumption that all co‐authors had agreed to the submission. However, the journal was informed on February 2, 2015, that 4 co‐authors on the paper had not consented to the submission and subsequent publication of this manuscript. Furthermore, an external evaluation commissioned by one of the co‐authors of the study protocol, patient follow‐up, and study results published in the manuscript has led to the conclusion that 6 of the 30 patients were invented and that follow‐up studies in 10 of the 30 patients were not performed or contradict patient data published in the manuscript.Based on these findings and at the request of the co‐authors who did not consent to publication, the Publisher has agreed to retract this manuscript. Behr, T. M., Liersch, T., Greiner‐Bechert, L., Griesinger, F., Béhé, M., Markus, P. M., Gratz, S., Angerstein, C., Brittinger, G., Becker, H., Goldenberg, D. M. and Becker, W. (2002), . Cancer, 94: 1373‐1381. doi: 10.1002/cncr.10308.