Identification of Tumor Specific Peptide as EpCAM Ligand and Its Potential Diagnostic and Therapeutic Clinical Application

Drug Delivery Opportunities in Esophageal Cancer: Current Treatments and Future Prospects

With one of the highest mortality rates of all malignancies, the 5-year survival rate for esophageal cancer is under 20%. Depending on the stage and extent of the disease, the current standard of care treatment paradigm includes chemotherapy or chemoradiotherapy followed by surgical esophagogastrectomy, with consideration for adjuvant immunotherapy for residual disease. This regimen has high morbidity, due to anatomic changes inherent in surgery, the acuity of surgical complications, and off-target effects of systemic chemotherapy and immunotherapy. We begin with a review of current treatments, then discuss new and emerging targets for therapies and advanced drug delivery systems. Recent and ongoing preclinical and early clinical studies are evaluating traditional tumor targets (e.g., human epidermal growth factor receptor 2), as well as promising new targets such as Yes-associated protein 1 or mammalian target of rapamycin to develop new treatments for this disease. Due the function and location of the esophagus, opportunities also exist to pair these treatments with a drug delivery strategy to increase tumor targeting, bioavailability, and intratumor concentrations, with the two most common delivery platforms being stents and nanoparticles. Finally, early results with antibody drug conjugates and chimeric antigenic receptor T cells show promise as upcoming therapies. This review discusses these innovations in therapeutics and drug delivery in the context of their successes and failures, with the goal of identifying those solutions that demonstrate the most promise to shift the paradigm in treating this deadly disease.

Visualization system based on hierarchical targeting for diagnosis and treatment of hepatocellular carcinoma

The accuracy and enrichment rate of targeted drugs largely determine the clinical diagnosis and treatment effect. Therefore, the accuracy and enrichment rate of targeted drugs should be improved. We designed a visual diagnosis and treatment system based on hierarchical targeting. It consists of multifunctional magnetic nanoparticles and a bio magnetic material. Bio-magnet mediated primary targeting can effectively improve the drug enrichment rate in the target tissue. SNF peptide/epithelial cell adhesion molecule antibody mediated targeting liver cancer stem cells (LCSCs) (secondary target) can improve the accuracy of the treatment and its outcomes. Low intensity focused ultrasound irradiation can explode nanoparticles around LCSCs, which can cause physical damage to cells. The combination of released interferon gamma and its receptor (tertiary target) can be used to initiate chemotherapy and immunotherapy. Using the optical properties of Fe₃O₄ and the phase transformation ability of perfluoropentane, the system can enhance photoacoustic and ultrasonic molecular imaging enabling diagnosis and treatment visualization. Targeting LCSCs can accurately provide physical, chemical, and immune treatment of Hepatocellular carcinoma, making the therapeutic effect more effective and thorough. This system may provide a new method for a more accurate visual diagnosis and treatment of tumors.

Epithelial Cell Adhesion Molecule (EpCAM) Expression Can Be Modulated via NFκB

The epithelial cell adhesion molecule (EpCAM) is considered an essential proliferation signature in cancer. In the current research study, qPCR induced expression of EpCAM was noted in acute lymphoblastic leukemia (ALL) cases. Costunolide, a sesquiterpene lactone found in crepe ginger and lettuce, is a medicinal herb with anticancer properties. Expression of EpCAM and its downstream target genes (Myc and TERT) wasdownregulated upon treatment with costunolide in Jurkat cells. A significant change in the telomere length of Jurkat cells was not noted at 72 h of costunolide treatment. An in silico study revealed hydrophobic interactions between EpCAM extracellular domain and Myc bHLH with costunolide. Reduced expression of NFκB, a transcription factor of EpCAM, Myc, and TERT in costunolide-treated Jurkat cells, suggested that costunolide inhibits gene expression by targeting NFκB and its downstream targets. Overall, the study proposes that costunolide could be a promising therapeutic biomolecule for leukemia.

Understanding the versatile roles and applications of EpCAM in cancers: from bench to bedside

Epithelial cell adhesion molecule (EpCAM) functions not only in physiological processes but also participates in the development and progression of cancer. In recent decades, extensive efforts have been made to decipher the role of EpCAM in cancers. Great advances have been achieved in elucidating its structure, molecular functions, pathophysiological mechanisms, and clinical applications. Beyond its well-recognized role as a biomarker of cancer stem cells (CSCs) or circulating tumor cells (CTCs), EpCAM exhibits novel and promising value in targeted therapy. At the same time, the roles of EpCAM in cancer progression are found to be highly context-dependent and even contradictory in some cases. The versatile functional modules of EpCAM and its communication with other signaling pathways complicate the study of this molecule. In this review, we start from the structure of EpCAM and focus on communication with other signaling pathways. The impacts on the biology of cancers and the up-to-date clinical applications of EpCAM are also introduced and summarized, aiming to shed light on the translational prospects of EpCAM.

Chimeric Antigen Receptor (CAR)-T Cell Immunotherapy Against Thoracic Malignancies: Challenges and Opportunities

Different from surgery, chemical therapy, radio-therapy and target therapy, Chimeric antigen receptor-modified T (CAR-T) cells, a novel adoptive immunotherapy strategy, have been used successfully against both hematological tumors and solid tumors. Although several problems have reduced engineered CAR-T cell therapeutic outcomes in clinical trials for the treatment of thoracic malignancies, including the lack of specific antigens, an immunosuppressive tumor microenvironment, a low level of CAR-T cell infiltration into tumor tissues, off-target toxicity, and other safety issues, CAR-T cell treatment is still full of bright future. In this review, we outline the basic structure and characteristics of CAR-T cells among different period, summarize the common tumor-associated antigens in clinical trials of CAR-T cell therapy for thoracic malignancies, and point out the current challenges and new strategies, aiming to provide new ideas and approaches for preclinical experiments and clinical trials of CAR-T cell therapy for thoracic malignancies.

Multi-modal imaging probe for EpCAM overexpressed in breast cancer

Breast cancer is a highly lethal and aggressive form of cancer. Early-stager diagnosis and intraoperative guidance are important endeavors for reducing associated morbidity and mortality among breast cancer patients. Epithelial cell adhesion molecule (EpCAM) is aberrantly expressed in the majority of breast carcinoma, making it an attractive imaging biomarker. Herein, we have designed novel EpCAM-targeting peptides (denoted as YQ-S) for precise breast carcinoma detection. The greater binding affinity of the designed peptide YQ-S2 over YQ-S1 and the reported peptide SNF was displayed on different cell lines with flow cytometry analysis, showing a positive correlation with the expression of EpCAM. Besides, YQ-S2 displayed an ideal biosafety profile with no evidence of any acute toxicity. Thus, YQ-S2 was chosen to represent YQ-S. By linking with the near-infrared fluorescent dye (MPA), we further developed the EpCAM-targeting probe (YQ-S2-MPA) for real-time imaging and fluorescence-guided resection of breast cancer tumors. In vivo imaging of the MCF-7 tumor-bearing model demonstrated higher tumor uptake of YQ-S2-MPA compared with that of SNF-MPA. The maximum tumor-to-normal tissue signal ratio of YQ-S2-MPA was 5.1, which was about 2 times that of SNF-MPA. Meanwhile, the metastatic lesions in 4T1 lung metastasis, and lymph node metastasis (LNM) mice were successfully detected under this imaging system. Notably, YQ-S2-MPA had excellent performance in surgical navigation studies in the preclinical models. Moreover, we exploited the ^99mTc-HYNIC-YQ-S2 to localize EpCAM positive tumors successfully. These data proved that YQ-S2 can distinguish EpCAM-positive orthotopic and metastatic tumors from surrounding normal tissues accurately, and possesses the clinical potential as a surgical navigation probe.

Epithelial cell adhesion molecule (EpCAM) binding short peptides derived from antibody MOC-31; De-novo design, synthesis and their in-vitro evaluation

Epithelial cell adhesion molecule (EpCAM) is one of the critical bio-maker for circulating tumor cells (CTC) detection. For capturing CTC, antibody-antigen-based techniques have mainly been explored. However, the expensiveness and tedious manufacturing process have posed certain limitations for antibody-based techniques for its wide applications in cell capturing. On the other hand, peptides are inexpensive bimolecular probes with high specificity and tunability. Although there are few reports on EpCAM binding peptides are available in literature, those peptides were selected through random library screening. Interestingly, de-novo design of the peptides against EpCAM has not been reported till date. For the first time, we have developed a small peptide (Pep14) from the complementary derived region (CDRs) of antibody MOC31 through systematic virtual screening. Selected peptide has demonstrated good binding affinity towards EpCAM with dissociation constant (Kd) of 870 nM and found to be co-localized with the anti-EpCAM antibody in EpCAM expressing cancer cells (MCF-7). Therefore, the short peptide Pep14 hold promise for capturing circulatory tumor cells through EpCAM binding.

Peptide-Conjugated Nano Delivery Systems for Therapy and Diagnosis of Cancer

Peptides are strings of approximately 2-50 amino acids, which have gained huge attention for theranostic applications in cancer research due to their various advantages including better biosafety, customizability, convenient process of synthesis, targeting ability via recognizing biological receptors on cancer cells, and better ability to penetrate cell membranes. The conjugation of peptides to the various nano delivery systems (NDS) has been found to provide an added benefit toward targeted delivery for cancer therapy. Moreover, the simultaneous delivery of peptide-conjugated NDS and nano probes has shown potential for the diagnosis of the malignant progression of cancer. In this review, various barriers hindering the targeting capacity of NDS are addressed, and various approaches for conjugating peptides and NDS have been discussed. Moreover, major peptide-based functionalized NDS targeting cancer-specific receptors have been considered, including the conjugation of peptides with extracellular vesicles, which are biological nanovesicles with promising ability for therapy and the diagnosis of cancer.

Targeted imaging of esophageal adenocarcinoma with a near-infrared fluorescent peptide

BACKGROUND

Targeted optical imaging offers a noninvasive and accurate method for the early detection of gastrointestinal tumors, especially for flat appearances. In our previous study, a sequence of SNFYMPL (SNF) was identified as a specific peptide to bind to esophageal carcinoma using phage-display technology. This study aimed to evaluate the tumor-targeting efficacy of Cy5.5-conjugated SNF probe for imaging of esophageal carcinoma in vitro and in vivo.

METHODS

The SNF-Cy5.5 probe was synthesized and then identified using High Performance Liquid Chromatography (HPLC) and mass spectrometry (MS). Confocal fluorescence imaging and Flow cytometry analysis were performed to evaluate the binding specificity and the receptor binding affinity of SNF-Cy5.5 to OE33. In vivo imaging was performed to evaluate the targeting ability of SNF-Cy5.5 to esophageal carcinoma.

RESULTS

The confocal imaging and flow cytometry analysis showed that SNF-Cy5.5 bound specifically to the plasma membrane of OE33 cells with a high affinity. In vivo, for non-block group, SNF-Cy5.5 probe exhibited rapid OE33 tumor targeting during 24 h p.i. and excellent tumor-to-background contrast at 2 h p.i. For the block group, SNF-Cy5.5 was not observed in the mice after 4 h p.i. Ex vivo imaging also revealed that a higher fluorescent signal intensity value of the tumors was clearly observed in the non-block group than that in the block group (2.6 ± 0.32 × 10⁹ vs. 0.8 ± 0.08 × 10⁹, p < 0.05).

CONCLUSIONS

SNF-Cy5.5 was synthesized and characterized with a high efficiency and purity. The higher affinity, specificity, and tumor targeting efficacy of SNF-Cy5.5 were confirmed by in vitro and in vivo tests. SNF-Cy5.5 is a promising optical probe for the imaging of esophageal adenocarcinoma.

Peptides and pseudopeptide ligands: a powerful toolbox for the affinity purification of current and next-generation biotherapeutics

Following the consolidation of therapeutic proteins in the fight against cancer, autoimmune, and neurodegenerative diseases, recent advancements in biochemistry and biotechnology have introduced a host of next-generation biotherapeutics, such as CRISPR-Cas nucleases, stem and car-T cells, and viral vectors for gene therapy. With these drugs entering the clinical pipeline, a new challenge lies ahead: how to manufacture large quantities of high-purity biotherapeutics that meet the growing demand by clinics and biotech companies worldwide. The protein ligands employed by the industry are inadequate to confront this challenge: while featuring high binding affinity and selectivity, these ligands require laborious engineering and expensive manufacturing, are prone to biochemical degradation, and pose safety concerns related to their bacterial origin. Peptides and pseudopeptides make excellent candidates to form a new cohort of ligands for the purification of next-generation biotherapeutics. Peptide-based ligands feature excellent target biorecognition, low or no toxicity and immunogenicity, and can be manufactured affordably at large scale. This work presents a comprehensive and systematic review of the literature on peptide-based ligands and their use in the affinity purification of established and upcoming biological drugs. A comparative analysis is first presented on peptide engineering principles, the development of ligands targeting different biomolecular targets, and the promises and challenges connected to the industrial implementation of peptide ligands. The reviewed literature is organized in (i) conventional (α-)peptides targeting antibodies and other therapeutic proteins, gene therapy products, and therapeutic cells; (ii) cyclic peptides and pseudo-peptides for protein purification and capture of viral and bacterial pathogens; and (iii) the forefront of peptide mimetics, such as β-/γ-peptides, peptoids, foldamers, and stimuli-responsive peptides for advanced processing of biologics.

CAR-T Cell Therapy-An Overview of Targets in Gastric Cancer

Gastric cancer (GC) is one of the most commonly diagnosed malignancies and, unfortunately, still has a high mortality rate. Recent research points to CAR-T immunotherapy as a promising treatment for this disease. Using genetically engineered T cells designed to target a previously selected antigen, researchers are able to harness the natural anti-tumor activity of T cells. For therapy to be successful, however, it is essential to choose antigens that are present on tumor cells but not on healthy cells. In this review, we present an overview of the most important targets for CAR-T therapy in the context of GC, including their biologic function and therapeutic application. A number of clinical studies point to the following as important markers in GC: human epidermal growth factor receptor 2, carcinoembryonic antigen, mucin 1, epithelial cell adhesion molecule, claudin 18.2, mesothelin, natural-killer receptor group 2 member D, and folate receptor 1. Although these markers have been met with some success, the search for new and improved targets continues. Key among these novel biomarkers are the B7H6 ligand, actin-related protein 2/3 (ARP 2/3), neuropilin-1 (NRP-1), desmocollin 2 (DSC2), anion exchanger 1 (AF1), and cancer-related antigens CA-72-4 and CA-19-9.