Explore the vast range of titles available.

Anticytotoxic T lymphocyte-associated protein 4 (CTLA4) antibodies have shown potent antitumor activity, but systemic immune activation leads to severe immune-related adverse events, limiting clinical usage. We developed novel, conditionally active biologic (CAB) anti-CTLA4 antibodies that are active only in the acidic tumor microenvironment. In healthy tissue, this binding is reversibly inhibited by a novel mechanism using physiological chemicals as protein-associated chemical switches (PaCS). No enzymes or potentially immunogenic covalent modifications to the antibody are required for activation in the tumor. The novel anti-CTLA4 antibodies show similar efficacy in animal models compared to an analog of a marketed anti-CTLA4 biologic, but have markedly reduced toxicity in nonhuman primates (in combination with an anti-PD1 checkpoint inhibitor), indicating a widened therapeutic index (TI). The PaCS encompass mechanisms that are applicable to a wide array of antibody formats (e.g., ADC, bispecifics) and antigens. Examples shown here include antibodies to EpCAM, Her2, Nectin4, CD73, and CD3. Existing antibodies can be engineered readily to be made sensitive to PaCS, and the inhibitory activity can be optimized for each antigen’s varying expression level and tissue distribution. PaCS can modulate diverse physiological molecular interactions and are applicable to various pathologic conditions, enabling differential CAB antibody activities in normal versus disease microenvironments.

New strategies for cancer immunotherapy are needed since most solid tumors do not respond to current approaches. Here we used epithelial cell adhesion molecule EpCAM (a tumor-associated antigen highly expressed on common epithelial cancers and their tumor-initiating cells) aptamer-linked small-interfering RNA chimeras (AsiCs) to knock down genes selectively in EpCAM⁺ tumors with the goal of making cancers more visible to the immune system. Knockdown of genes that function in multiple steps of cancer immunity was evaluated in aggressive triple-negative and HER2⁺ orthotopic, metastatic, and genetically engineered mouse breast cancer models. Gene targets were chosen whose knockdown was predicted to promote tumor neoantigen expression (Upf2, Parp1, Apex1), phagocytosis, and antigen presentation (Cd47), reduce checkpoint inhibition (Cd274), or cause tumor cell death (Mcl1). Four of the six AsiC (Upf2, Parp1, Cd47, and Mcl1) potently inhibited tumor growth and boosted tumor-infiltrating immune cell functions. AsiC mixtures were more effective than individual AsiC and could synergize with anti–PD-1 checkpoint inhibition.

Near‐infrared photoimmunotherapy (NIR‐PIT) is a tumor‐specific treatment using monoclonal antibody (mAb) photosensitizer conjugates, followed by near‐infrared light irradiation. This study aimed to identify the optimum target for treating esophagogastric junction (EGJ) adenocarcinoma and to evaluate the efficacy of NIR‐PIT using mAbs in preclinical models. Tumor samples from 46 consecutive patients who had undergone surgery without any prior treatment for EGJ adenocarcinoma were assessed for expression and homogeneity of epidermal growth factor receptor (EGFR), human epidermal growth factor receptor 2 (HER2), and epithelial cell adhesion molecule (EpCAM) through immunohistochemistry. Results showed positive rates of 22%, 13%, and 98% for EGFR, HER2, and EpCAM, respectively, with EpCAM also demonstrating the highest homogeneity (93%). Therefore, EpCAM was selected as the optimal target for NIR‐PIT. The fully human monoclonal antibody targeting EpCAM, adecatumumab, was conjugated with the photosensitizer IR700 at different dye‐antibody ratios (DAR2, DAR4, DAR7) and tested on OE19 cells and xenograft mouse models under near‐infrared light irradiation. NIR‐PIT with adecatumumab‐IR700 significantly reduced tumor size and improved prognoses compared to controls, with DAR2 showing the best balance of efficacy and minimal side effects. Notable EpCAM expression and homogeneity underpin EpCAM as a promising target for NIR‐PIT in EGJ adenocarcinoma. The fully human anti‐EpCAM antibody may be suitable for NIR‐PIT in EGJ adenocarcinoma. Photoimmunotherapy (PIT) in vitro. OE19 cells formed blisters 3 h after laser illumination using adecatumumab‐IR700.

Summary Epithelial cell adhesion molecule (EpCAM) fused to IgG, IgA and IgM Fc domains was expressed to create IgG, IgA and IgM‐like structures as anti‐cancer vaccines in Nicotiana tabacum. High‐mannose glycan structures were generated by adding a C‐terminal endoplasmic reticulum (ER) retention motif (KDEL) to the Fc domain (FcK) to produce EpCAM‐Fc and EpCAM‐FcK proteins in transgenic plants via Agrobacterium‐mediated transformation. Cross‐fertilization of EpCAM‐Fc (FcK) transgenic plants with Joining chain (J‐chain, J and JK) transgenic plants led to stable expression of large quaternary EpCAM‐IgA Fc (EpCAM‐A) and IgM‐like (EpCAM‐M) proteins. Immunoblotting, SDS–PAGE and ELISA analyses demonstrated that proteins with KDEL had higher expression levels and binding activity to anti‐EpCAM IgGs. IgM showed the strongest binding among the fusion proteins, followed by IgA and IgG. Sera from BALB/c mice immunized with these vaccines produced anti‐EpCAM IgGs. Flow cytometry indicated that the EpCAM‐Fc fusion proteins significantly activated CD8+ cytotoxic T cells, CD4+ helper T cells and B cells, particularly with EpCAM‐FcKP and EpCAM‐FcP (FcKP) × JP (JKP). The induced anti‐EpCAM IgGs captured human prostate cancer PC‐3 and colorectal cancer SW620 cells. Sera from immunized mice inhibited cancer cell proliferation, migration and invasion; down‐regulated proliferation markers (PCNA, Ki‐67) and epithelial–mesenchymal transition markers (Vimentin); and up‐regulated E‐cadherin. These findings suggest that N. tabacum can produce effective vaccine candidates to induce anti‐cancer immune responses.

Colorectal cancer (CRC) is one of the most common malignancies worldwide. In spite of various attempts to ameliorate outcome by escalating treatment, significant improvement is lacking particularly in the adjuvant setting. It has been proposed that cancer stem cells (CSCs) and the epithelial‐to‐mesenchymal transition (EMT) are at least partially responsible for therapy resistance in CRC. The epithelial cell adhesion molecule (EpCAM) was one of the first CSC antigens to be described. Furthermore, an EpCAM‐specific antibody (edrecolomab) has the merit of having launched the era of monoclonal antibody treatment in oncology in the 1990s. However, despite great initial enthusiasm, monoclonal antibody treatment has not proven successful in the adjuvant treatment of CRC patients. In the meantime, new insights into the function of EpCAM in CRC have emerged and new drugs targeting various epitopes have been developed. In this review article, we provide an update on the role of EpCAM in CSCs and EMT, and emphasize the potential predictive selection criteria for novel treatment strategies and refined clinical trial design. Stem Cells Translational Medicine 2018;7:495–501 Conceptual framework for therapeutic targeting of EpCAM in malignant disease. Malignant tumors, including those of the colorectum, are characterized by marked heterogeneity and harbor phenotypically and functionally distinct subsets of cells. EpCAM‐targeted treatment of colorectal cancer is promising as it should affect many of these subsets including bulk tumor cells, CSCs, CTCs, and MET cells (only EMT cells lacking target expression will be spared). Expected outcomes are the containment (or even shrinkage) of the primary tumor as well as the inhibition of metastatic dissemination and recurrence. Traditionally, EpCAM‐directed treatments have focused on antibody‐based compounds targeting surface epitopes (i.e., EpEX). The recognition of nuclear translocation of EpICD as a potent oncogenic trigger now asks for complementary approaches involving membrane permeable drugs (i.e., small molecules). Abbreviations: CSC, cancer stem cell; CTC, circulating tumor cell; EMT, epithelial‐to‐mesenchymal transition; EpCAM, epithelial cell adhesion molecule; EpEX, EpCAM extracellular domain; EpICD, EpCAM intracellular domain; MET, mesenchymal‐to‐epithelial transition.

The diagnosis of leptomeningeal metastases (LM) of solid tumors is complicated due to low sensitivities of both magnetic resonance imaging (MRI) and cytology. MRI has a sensitivity of 76% for the diagnosis of LM and cerebrospinal fluid (CSF) cytology has a sensitivity of 44–67% at first lumbar puncture which increases to 84–91% upon second CSF sampling. Epithelial cell adhesion molecule (EpCAM) is expressed by solid tumors of epithelial origin like non-small-cell lung cancer, breast cancer or ovarium cancer. Recently, a CELLSEARCH® assay and flow cytometry laboratory techniques have been developed to detect circulating tumor cells (CTCs) of epithelial origin in CSF. These laboratory techniques are based on capture antibodies labelled with different fluorescent tags against EpCAM. In this review, we provide an overview of the available laboratory techniques and diagnostic accuracy for tumor cell detection in CSF. The reported sensitivities of the EpCAM-based CTC assays for the diagnosis of LM across the different studies are highly promising and vary between 76 and 100%. An overview of the different EpCAM-based techniques for the enumeration of CTCs in the CSF is given and a comparison is made with CSF cytology for the diagnoses of LM from epithelial tumors.

Purpose Epithelial cell adhesion molecule (EpCAM) is a potential therapeutic target and anchoring molecule for circulating and disseminated tumour cells (CTC/DTC) in liquid biopsy. In this study, we aimed to construct EpCAM-specific immuno-positron emission tomography (immunoPET) imaging probes and assess the diagnostic abilities in preclinical cancer models. Methods By engineering six single-domain antibodies (e.g., EPCD1 − 6) targeting EpCAM of different binding properties and labelling with 68 Ga (T 1/2  = 1.1 h) and 18 F (T 1/2  = 110 min), we developed a series of EpCAM-targeted immunoPET imaging probes. The probes' pharmacokinetics and diagnostic accuracies were investigated in cell-derived human colorectal (LS174T) and esophageal cancer (OE19) tumour models. Results Based on in vitro binding affinities and in vivo pharmacokinetics of the first three tracers ([ 68 Ga]Ga-NOTA-EPCD1, [ 68 Ga]Ga-NOTA-EPCD2, and [ 68 Ga]Ga-NOTA-EPCD3), we selected [ 68 Ga]Ga-NOTA-EPCD3 for tumour imaging which showed an average tumour uptake of 2.06 ± 0.124%ID/g ( n  = 3) in LS174T cell-derived tumour model. Development and characterisation of [ 18 F]AIF-RESCA-EPCD3 showed comparable tumour uptake of 1.73 ± 0.0471%ID/g ( n  = 3) in the same tumour model. Further validation of [ 68 Ga]Ga-NOTA-EPCD3 in OE19 cell-derived tumour model showed an average tumour uptake of 4.27 ± 1.16%ID/g and liver uptake of 13.5 ± 1.30%ID/g ( n  = 3). Near-infrared fluorescence imaging with Cy7-EPCD3 confirmed the in vivo pharmacokinetics and relatively high liver accumulation. We further synthesized another three 18 F-labeled nanobody tracers ([ 18 F]AIF-RESCA-EPCD4, [ 18 F]AIF-RESCA-EPCD5, and [ 18 F]AIF-RESCA-EPCD6) and found that [ 18 F]AIF-RESCA-EPCD6 had the best pharmacokinetics with low background. [ 18 F]AIF-RESCA-EPCD6 showed explicit uptake in the subcutaneously inoculated OE19 tumour model with an average uptake of 4.70 ± 0.26%ID/g ( n  = 3). In comparison, the corresponding tumour uptake (0.17 ± 0.25%ID/g, n  = 3) in the EPCD6 blocking group was substantially lower ( P  < 0.001), indicating the targeting specificity of the tracer. Conclusions We developed a series of 68 Ga/ 18 F-labeled nanobody tracers targeting human EpCAM. ImmunoPET imaging with [ 18 F]AIF-RESCA-EPCD6 may facilitate better use of EpCAM-targeted therapeutics by noninvasively displaying the target's expression dynamics.

Key message Transgenic tobacco plant expressed EpCAM-Fc fusion proteins to induce in vivo immune responses producing anti-EpCAM antibodies inhibiting human colorectal cancer cell invasion and migration. Plant is emerging as a promising alternative to produce valuable immunotherapeutic vaccines. In this study, we examined the in vivo anti-cancer efficacy of epidermal cell adhesion molecule (EpCAM)-Fc and EpCAM-FcK fusion proteins produced in transgenic plants as colorectal cancer vaccine candidates. Mice were injected with plant-derived EpCAM-Fc (EpCAM-Fc P ) and EpCAM-Fc P tagged with KDEL (ER retention signal) (EpCAM-FcK P ), using mammalian-derived EpCAM-Fc (EpCAM-Fc M ) as positive control. Total IgGs from the immunized mice were used to assess immune responses. ELISA tests revealed that IgGs from mice immunized with EpCAM-FcK P (EpCAM-FcK P IgG) exhibited the highest absorbance value for binding affinity to recombinant EpCAM-Fc M compared to IgGs from mice immunized with EpCAM-Fc P (EpCAM-Fc P IgG) and EpCAM-Fc M (EpCAM-Fc M IgG). Bio-layer interferometry revealed that EpCAM-FcK P IgG had a higher affinity value than EpCAM-Fc M IgG and EpCAM-Fc P IgG. Cell ELISA revealed that EpCAM-FcK P IgG exhibited the highest binding activity to EpCAM-positive cells SW480 and SW620 compared to EpCAM-Fc P IgG, EpCAM-Fc M IgG, and anti-EpCAM mAb. In the transwell invasion assay, EpCAM-FcK P IgG significantly decreased the numbers of invaded SW480 and SW620 cells compared to EpCAM-Fc P IgG, whereas EpCAM-Fc M IgG had similar numbers. In the wound healing assay, EpCAM-FcK P IgG showed higher migration inhibition compared to EpCAM-Fc P IgG in both cell types, with similar results to EpCAM-Fc M IgG in SW620 cells. These results confirm the applicability of plant systems to produce EpCAM-Fc vaccine candidates, inducing the production of anti-EpCAM IgGs against colorectal cancer cells.

Adoptive chimeric antigen receptor-modified T or NK cells (CAR-T or CAR-NK) offer new options for cancer treatment. CAR-T therapy has achieved encouraging breakthroughs in the treatment of hematological malignancies. However, their therapeutic efficacy against solid tumors is limited. New regimens, including combinations with chemical drugs, need to be studied to enhance the therapeutic efficacy of CAR-T or NK cells for solid tumors. An epithelial cell adhesion molecule- (EpCAM-) specific second-generation CAR was constructed and transduced into NK-92 cells by lentiviral vectors. Immune effects, including cytokine release and cytotoxicity of the CAR-NK-92 cells against EpCAM-positive colon cancer cells, were evaluated in vitro. Synergistic effects of regorafenib and CAR-NK-92 cells were analyzed in a mouse model with human colorectal cancer xenografts. The CAR-NK-92 cells can specifically recognize EpCAM-positive colorectal cancer cells and release cytokines, including IFN-γ, perforin, and granzyme B, and show specific cytotoxicity in vitro. The growth suppression efficacy of combination therapy with regorafenib and CAR-NK-92 cells on established EpCAM-positive tumor xenografts was more significant than that of monotherapy with CAR-NK-92 cells or regorafenib. Our results provided a novel strategy to treat colorectal cancer and enhance the therapeutic efficacy of CAR-modified immune effector cells for solid tumors.

Objective To construct chimeric antigen receptor (CAR)-T cells targeting epithelial cell adhesion molecule (EpCAM) antigen (anti-EpCAM-CAR-T). Methods A third-generation CAR-T cell construct used a single-chain variable fragment derived from monoclonal antibody against human EpCAM. Peripheral blood mononuclear cells were extracted from volunteers. The proportion of cluster of differentiation 8 positive (CD8+) and CD4 + T cells was measured using flow cytometry. Western blot was used to detect the expression of EpCAM-CAR. The killing efficiency was detected using the MTT assay and transwell assay, and the secretion of killer cytokines tumour necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) was detected using the ELISA. The inhibitory effect of EpCAM-CAR-T on colorectal cancer in vivo was detected using xenografts. Results It was found that T cells expanded greatly, and the proportion of CD3+, CD8 + and CD4 + T cells was more than 60%. Furthermore, EpCAM-CAR-T cells had a higher tumour inhibition rate in the EpCAM expression positive group than in the negative group ( P  < 0.05). The secretion of killer cytokines TNF-α and IFN-γ in the EpCAM expression positive cell group was higher than that in the negative group ( P  < 0.05). In the experimental group treated with EpCAM-CAR-T cells, the survival rate of nude mice was higher ( P  < 0.05), and the tumour was smaller than that in the blank and control groups ( P  < 0.05). The secretion of serum killer cytokines TNF-α and IFN-γ in tumour-bearing nude mice in the experimental group treated with EpCAM-CAR-T cells was higher than that in the blank and control groups ( P  < 0.05). Conclusion This study successfully constructed EpCAM-CAR cells and found that they can target and recognise EpCAM-positive tumour cells, secrete killer cytokines TNF-α and IFN-γ and better inhibit the growth and metastasis of colorectal cancer in vitro and in vivo than unmodified T cells.