The Use of Fluorescent Anti-CEA Antibodies to Label, Resect and Treat Cancers: A Review

Accurate Co-Localization of Luciferase Expression and Fluorescent Anti-CEA Antibody Targeting of Liver Metastases in an Orthotopic Mouse Model of Colon Cancer

BACKGROUND

The present study aimed to validate the accuracy of a tumor-specific antibody to target liver metastases of colorectal cancer.

METHODS

A humanized anti-CEA antibody conjugated to a fluorescent dye (M5A-IR800) was tested for targeting human colorectal cancer liver metastases (CRLMs) expressing luciferase in an orthotopic mouse model. Orthotopic mouse models of CRLMs were established by implanting fragments of a luciferase-expressing human colorectal cancer cell line, LS174T, in the liver of nude mice. Mice received 50 µg M5A-IR800 72 h prior to imaging. To test co-localization, bioluminescence imaging was performed using D-luciferin, which was given via intraperitoneal injection just prior to imaging.

RESULTS

Tumors were able to be visualized non-invasively through the skin with the luciferase-luciferin signal. Intra-abdominal imaging showed accurate labeling of CRLMs with M5A-IR800, which co-localized with the luciferase-luciferin signal.

CONCLUSIONS

The present results validate the accuracy of a tumor-specific anti-CEA antibody in targeting liver metastases of colorectal cancer.

Ovarian cancer: Diagnosis and treatment strategies (Review)

Ovarian cancer is a malignant tumor that seriously endangers health. Early ovarian cancer symptoms are frequently challenging to detect, resulting in a large proportion of patients reaching an advanced stage when diagnosed. Conventional diagnosis relies heavily on serum biomarkers and pathological examination, but their sensitivity and specificity require improvement. Targeted therapy inhibits tumor growth by targeting certain characteristics of tumor cells, such as signaling pathways and gene mutations. However, the effectiveness of targeted therapy varies among individuals due to differences in their unique biological characteristics and requires individualized strategies. Immunotherapy is a promising treatment for ovarian cancer due to its long-lasting antitumor effect. Nevertheless, issues such as variable efficacy, immune-associated adverse effects and drug resistance remain to be resolved. The present review discusses the diagnostic strategies, rationale, treatment strategies and prospects of targeted therapy and immunotherapy for ovarian cancer.

A Concept for Preoperative and Intraoperative Molecular Imaging and Detection for Assessing Extent of Disease of Solid Tumors

The authors propose a concept of "systems engineering," the approach to assessing the extent of diseased tissue (EODT) in solid tumors. We modeled the proof of this concept based on our clinical experience with colorectal carcinoma (CRC) and gastrinoma that included short and long-term survival data of CRC patients. This concept, applicable to various solid tumors, combines resources from surgery, nuclear medicine, radiology, pathology, and oncology needed for preoperative and intraoperative assessments of a patient's EODT. The concept begins with a patient presenting with biopsy-proven cancer. An appropriate preferential locator (PL) is a molecule that preferentially binds to a cancer-related molecular target (i.e., tumor marker) lacking in non-malignant tissue and is the essential element. Detecting the PL after an intravenous injection requires the PL labeling with an appropriate tracer radionuclide, a fluoroprobe, or both. Preoperative imaging of the tracer's signal requires molecular imaging modalities alone or in combination with computerized tomography (CT). These include positron emission tomography (PET), PET/CT, single-photon emission computed tomography (SPECT), SPECT/CT for preoperative imaging, gamma cameras for intraoperative imaging, and gamma-detecting probes for precise localization. Similarly, fluorescent-labeled PLs require appropriate cameras and probes. This approach provides the surgeon with real-time information needed for R0 resection.

Fluorescence and tracers in surgery: the coming future

The revolution that we are seeing in the world of surgery will determine the way we understand surgical approaches in coming years. Since the implementation of minimally invasive surgery, innovations have constantly been developed to allow the laparoscopic approach to go further and be applied to more and more procedures. In recent years, we have been in the middle of another revolutionary era, with robotic surgery, the application of artificial intelligence and image-guided surgery. The latter includes 3D reconstructions for surgical planning, virtual reality, holograms or tracer-guided surgery, where ICG-guided fluorescence has provided a different perspective on surgery. ICG has been used to identify anatomical structures, assess tissue perfusion, and identify tumors or tumor lymphatic drainage. But the most important thing is that this technology has come hand in hand with the potential to develop other types of tracers that will facilitate the identification of tumor cells and ureters, as well as different light beams to identify anatomical structures. These will lead to other types of systems to assess tissue perfusion without the use of tracers, such as hyperspectral imaging. Combined with the upcoming introduction of ICG quantification, these developments represent a real revolution in the surgical world. With the imminent implementation of these technological advances, a review of their clinical application in general surgery is timely, and this review serves that aim.

Revealing tumor cells and tissues with high selectivity through folic acid-targeted nanofluorescence probes responsive to acidic microenvironments

Tumor-specific fluorescent probes must fulfill the dual requirements of targeted accumulation within tumors and high-resolution imaging capabilities. To achieve both tumor-targeted accumulation and high-resolution imaging performance, we developed a composite comprising an acid-responsive bodipy conjugated to amphiphilic PEG-b-PLA polymer, along with folic acid (FA)-modified PEG-b-PLA as a targeting moiety for active tumor-specific accumulation. Finally, a novel assembly of hybrid fluorescent nanoparticles was successfully synthesized by integrating these two components, demonstrating exceptional responsiveness to acidic conditions for fluorescence excitation and remarkable tumor-targeted accumulation capabilities. We conducted comprehensive in vitro and in vivo investigations employing techniques such as analysis of physicochemical properties, fluorescence-based probes detection at varying pH levels, assessment of in vitro cytotoxicity, evaluation of cellular uptake capacity, analysis of lysosomal co-localization imaging, examination of tumor fluorescence images in vivo, and investigation of biological distribution patterns. The results demonstrated that the acid-responsive nanofluorescence probe we designed and synthesized possesses desirable physical and chemical characteristics, including a small particle size and low cytotoxicity. Moreover, it exhibits rapid real-time response to acidic environments and displays enhanced fluorescence intensity, enabling the real-time tracking of probe entry into tumor cells as well as intracellular lysozyme accumulation. We achieved highly specific in vivo tumor visualization by combining nanoprobes targeting folate receptor. Through imaging cervical tumor mice, we demonstrated the precise imaging performance and high targeted accumulation of FA-targeted nanofluorescence probes in tumor tissue. Furthermore, we confirmed the in vivo safety of the FA-targeted nanofluorescence probe through biological distribution analysis. These findings highlight the potential widespread application of FA-targeted acid-responsive nanofluorescence probes for selective imaging of tumor cells and tissues.

Carcinoembryonic antigen in the diagnosis, treatment, and follow-up of focal liver lesions

In this editorial review, we comment on the article published in the recent issue of the World Journal of Gastrointestinal Surgery. Carcinoembryonic antigen (CEA) is a fetal glycoprotein and can be secreted in very small amounts from healthy adults after birth. CEA is widely used not only for diagnostic tumor markers but also importantly for the management of some gastrointestinal tumors. The most common clinical use is surveillance for the monitoring of colorectal carcinoma. However, CEA can become elevated in several malign or benign characterized pathologies. Serum CEA level may vary depending on the location of the lesion, whether it metastasizes or not, and its histopathological characteristics. It has been determined that cases with high preoperative CEA have a more aggressive course and the risk of metastasis to the lymph tissue and liver increases. In this editorial review, we focused on evaluating the role of CEA in clinical practice with a holistic approach, including the diagnostic and prognostic significance of CEA in patients with focal liver lesions, the role of CEA in follow-up after definitive surgery, and also hepatic resection for metastasis, and the management of all patients with raised CEA.

Highly bright and stable CsPbBr3 perovskite nanocrystals with amphiphilic polymer binding based dual-readout lateral flow immunoassay for detection of carcinoembryonic antigen

Rapid and highly sensitive detection of tumor marker (TM) is critical for the early diagnosis and treatment of cancers. Herein, utilizing highly bright and water-stable CsPbBr3 perovskite nanocrystals (NCs) capped with amphiphilic polymer ligand of octylamine-modified polyacrylic acid (OPA) and gold nanoparticles (AuNPs) as reporters, a lateral flow immunoassay (LFIA) strip is developed for fluorescence and colorimetric dual-mode detection of carcinoembryonic antigen (CEA). The prepared CsPbBr3 NCs capped by an amphiphilic polymeric of OPA ligand showed high stability and bright fluorescence. Moreover, the AuNPs immunoprobes were captured with CEA antigen and quench the green fluorescence of CsPbBr3/OPA NCs on the T line due to the inner filter effect (IFE). Therefore, CEA could be quantitative analyzed by the dual-readout of fluorescence and colorimetric signal. The detection limits of CEA can reach as low as 0.023 ng/mL and 0.027 ng/mL for the fluorescence and colorimetric mode, respectively. Good specificity and reproducibility were also demonstrated for this method. Finally, the CsPbBr3/OPA NCs-based LFIA showed good accuracy in detection of CEA level from clinical serum samples. This work firstly enables the application of CsPbBr3 perovskite NCs in a LFIA, displaying great potential in point-of-care clinical diagnosis.

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

INTRODUCTION

Gastric 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.

METHODS

MKN45 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.

RESULTS

In 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.

CONCLUSIONS

Humanized 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.

Indocyanine green dye and its application in gastrointestinal surgery: The future is bright green

Indocyanine green (ICG) is a water-soluble fluorescent dye that is minimally toxic and widely used in gastrointestinal surgery. ICG facilitates anatomical identification of structures (e.g., ureters), assessment of lymph nodes, biliary mapping, organ perfusion and anastomosis assessment, and aids in determining the adequacy of oncological margins. In addition, ICG can be conjugated to artificially created antibodies for tumour markers, such as carcinoembryonic antigen for colorectal, breast, lung, and gastric cancer, prostate-specific antigen for prostate cancer, and cancer antigen 125 for ovarian cancer. Although ICG has shown promising results, the optimization of patient factors, dye factors, equipment, and the method of assessing fluorescence intensity could further enhance its utility. This review summarizes the clinical application of ICG in gastrointestinal surgery and discusses the emergence of novel dyes such as ZW-800 and VM678 that have demonstrated appropriate pharmacokinetic properties and improved target-to-background ratios in animal studies. With the emergence of robotic technology and the increasing reporting of ICG utility, a comprehensive review of clinical application of ICG in gastrointestinal surgery is timely and this review serves that aim.

Anti-mucin 4 fluorescent antibody brightly targets colon cancer in patient-derived orthotopic xenograft mouse models: A proof-of-concept study for future clinical applications

BACKGROUND

There is a high rate of positive surgical margins with resection of liver metastases in colorectal cancer (CRC). The present study reports using a fluorescent anti-mucin 4 (MUC4) antibodies to label primary CRC and liver metastases to better visualize tumor margins in mouse models.

METHODS

Western blotting for MUC4 protein expression of normal colon and CRC tumor lysates was performed. Orthotopic primary and liver metastatic CRC mouse models received anti-MUC4 antibody conjugated to IR800 (MUC4-IR800). Mice were sacrificed and imaged after 48 hours.

RESULTS

Western blotting demonstrated increased MUC4 expression in a human CRC cell line and patient-derived primary and liver-metastatic CRCs. The LS174T orthotopic primary CRC model tumor to background ratio (TBR) was 2.04 (±0.35). The patient-derived orthotopic xenograft (PDOX) primary CRC model TBR was 2.17 (±0.35). The PDOX liver metastasis model TBR was 1.56 (±0.53).

CONCLUSION

MUC4-IR800 provided bright labeling of primary and liver tumors in CRC orthotopic mouse models, demonstrating their future clinical potential for margin visualization in fluorescence guided surgery.

A Novel Signaling Strategy for an Ultrasensitive Photoelectrochemical Immunoassay Based on Electro-Fenton Degradation of Liposomes on a Photoelectrode

A signaling strategy can directly determine the analytical performance and application scope of photoelectrochemical (PEC) immunoassays, so it is of great significance to develop an effective signaling strategy. The electro-Fenton reaction has been extensively used to degrade organic pollutants, but it has not been applied to PEC immunoassays. Herein, we report a novel signaling strategy for a PEC immunoassay based on electro-Fenton degradation of liposomes (Lip) on a photoelectrode. Lip vesicles are coated on Au@TiO₂ core-shell photoactive material, which can prevent ascorbic acid (AA) from scavenging photogenerated holes. In the presence of a target, the immunomagnetic bead labels are converted to Fe³⁺ for electro-Fenton reaction, and hydroxyl radicals generated by the electro-Fenton reaction can degrade the Lip vesicles on the photoelectrode. Because of the degradation of Lip vesicles, photogenerated holes can be scavenged more effectively by AA, leading to an increase in photocurrent. Based on the electro-Fenton-regulated interface electron transfer, the sensitive "signal on" PEC immunoassay of a carcinoembryonic antigen is achieved, which features a dynamic range from 0.05 to 5 × 10⁴ pg mL^-1 and a detection limit of 0.01 pg mL^-1. Our work provides a novel and efficient PEC immunoassay platform by introducing the electro-Fenton reaction into PEC analysis.

Far-Red Fluorescent Murine Glioma Model for Accurate Assessment of Brain Tumor Progression

Glioma is the most common brain tumor, for which no significant improvement in life expectancy and quality of life is yet possible. The creation of stable fluorescent glioma cell lines is a promising tool for in-depth studies of the molecular mechanisms of glioma initialization and pathogenesis, as well as for the development of new anti-cancer strategies. Herein, a new fluorescent glioma GL261-kat cell line stably expressing a far-red fluorescent protein (TurboFP635; Katushka) was generated and characterized, and then validated in a mouse orthotopic glioma model. By using epi-fluorescence imaging, we detect the fluorescent glioma GL261-kat cells in mice starting from day 14 after the inoculation of glioma cells, and the fluorescence signal intensity increases as the glioma progresses. Tumor growth is confirmed by magnetic resonance imaging and histology. A gradual development of neurological deficit and behavioral alterations in mice is observed during glioma progression. In conclusion, our results demonstrate the significance and feasibility of using the novel glioma GL261-kat cell line as a model of glioma biology, which can be used to study the initialization of glioma and monitor its growth by lifetime non-invasive tracking of glioma cells, with the prospect of monitoring the response to anti-cancer therapy.