Enhancement of antitumor activity by using a fully human gene encoding a single-chain fragmented antibody specific for carcinoembryonic antigen.

Human leukocyte antigen and/or costimulatory molecules are frequently lacking in metastatic tumor cells, and thus tumor cells are able to escape from the immune system. Although lymphocytes with a chimeric antigen receptor (CAR) is a promising approach for overcoming this challenge in cancer immunotherapy, administration of modified T cells alone often demonstrates little efficacy in patients. Therefore, in order to enhance the antitumor activity of immune cells in the cancer microenvironment, we used lymphocytes expressing CAR in combination with a fusion protein of IL-2 that contained the single-chain fragmented antibody (scFv) specific for the carcinoembryonic antigen.

Corrigendum to "Molecular Characterization of a Fully Human Chimeric T-Cell Antigen Receptor for Tumor-Associated Antigen EpCAM".

[This corrects the article DOI: 10.1155/2012/853879.].

High expression of fusion proteins consisting of a single-chain variable fragment antibody against a tumor-associated antigen and interleukin-2 in Escherichia coli.

Background/aim: The aim of this study was to establish a strategy for high-level production of single-chain variable fragment (scFv) antibodies fused with interleukin-2 (IL-2) in Escherichia coli.

Materials And Methods: We constructed two fusion sequences consisting of a scFv gene derived from a mouse monoclonal antibody against a tumor-associated antigen (MK-1) and human Interleukin-2(IL-2) gene, ligated the fusions into pET15b and transformed into three different E. coli strains.

Optimal production of a fusion protein consisting of a single-chain variable fragment antibody against a tumor-associated antigen and interleukin-2 in fed-batch culture of Pichia pastoris.

Background/aim: The aim of the present study was to establish the strategy for producing a single-chain variable fragment (scFv) antibody fused with interleulin-2 (IL2) by Pichia pastoris and to optimize production during fed-batch cultivation in a 5-l fermenter.

Materials And Methods: We constructed a fusion sequence consisting of an scFv gene derived from a mouse monoclonal antibody against a tumor-associated antigen (designated MK-1 antigen) and human interleulin-2 (IL-2) gene, ligated the sequences to expression vector pPICZα-A and separately transformed the constructs into Pichia pastoris strains GS115 and KM71H.

Results: The highest concentration of secreted fusion protein, 738 ± 44 mg/l, was obtained after a 60-h induction.

Potent and specific antitumor effect of CEA-targeted photoimmunotherapy.

Conventional photodynamic therapy (PDT) for cancer is limited by the insufficient efficacy and specificity of photosensitizers. We herein describe a highly effective and selective tumor-targeted PDT using a near-infrared (NIR) photosensitizer, IRDye700DX, conjugated to a human monoclonal antibody (Ab) specific for carcinoembryonic antigen (CEA). The antitumor effects of this Ab-assisted PDT, called photoimmunotherapy (PIT), were investigated in vitro and in vivo.

Tumor growth inhibition by sonodynamic therapy using a novel sonosensitizer.

Sonodynamic therapy (SDT) with low-intensity ultrasound combined with a sonosensitizer may be a promising approach to cancer therapy. Use of ultrasound has the advantage of being noninvasive, with deep-penetration properties, and convenient because of the low or no sensitivity of sonosensitizers to light. In this study, SDT with a novel sonosensitizer (a porphyrin derivative) was evaluated in vitro and in vivo.

Molecular characterization of a fully human chimeric T-cell antigen receptor for tumor-associated antigen EpCAM.

The transduction of T cells to express chimeric T-cell antigen receptor (CAR) is an attractive strategy for adaptive immunotherapy for cancer, because the CAR can redirect the recognition specificity of T cells to tumor-associated antigens (TAAs) on the surface of target cells, thereby avoiding the limitations of HLA restriction. However, there are considerable problems with the clinical application of CAR, mostly due to its xenogeneic components, which could be immunogenic in humans. Moreover, while extensive studies on the CARs have been performed, the detailed molecular mechanisms underlying the activation of CAR-grafted T cells remain unclear.

Enhancement of the antitumor effect on combination therapy of an anticancer drug and its antibody against carcinoembryonic antigen.

Background: Carcinoembryonic antigen (CEA) is frequently overexpressed in various types of human cancers and is associated with cell adhesion. There are three possible mechanisms of cancer therapy that employ anti-CEA antibody (Ab): Ab-dependent cell-mediated cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC) or the prevention of CEA interaction with the extracellular matrix and/or intercellular adhesion molecules resulting in anoikis. In this study, the effect of C2-74, a human anti-CEA monoclonal Ab was evaluated.

Sonodynamic cancer therapy: a non-invasive and repeatable approach using low-intensity ultrasound with a sonosensitizer.

The low-intensity ultrasound that is used in clinical diagnoses, such as abdomen echo inspection, is a non-invasive treatment, and penetrates deeper into the body than light. Recently, sonodynamic therapy (SDT), which uses low-intensity ultrasound together with a sonosensitizer, has been developed for cancer therapy in applying such properties of ultrasound. So far, most sonosensitizers that have been developed are sensitive to light as well as ultrasound, implying that the shortcomings of photosensitizers used during photodynamic therapy, such as skin sensitivity, still need to be overcome in SDT.

Construction and molecular characterization of human chimeric T-cell antigen receptors specific for carcinoembryonic antigen.

Background: Chimeric T-cell antigen receptors (CAR) provide a promising approach for adoptive T-cell immunotherapy of cancer. Extensive studies on CARs have been conducted, but the detailed molecular mechanisms of the activation of a CAR-grafted T-cell remain ambiguous. This study constructed a CAR bearing anti-carcinoembryonic antigen (CEA) derived from a human monoclonal antibody (clone C2-45), and investigated the molecular basis of the CAR-mediated activation in Jurkat T-cells.

Claudin-1 protein is a major factor involved in the tumorigenesis of colorectal cancer.

Background: The molecular and morphological alterations of the tight junctions in colorectal cancer (CRC) are still poorly understood. The possible involvement of claudin-1 (CL-1), one of the major tight junctional proteins (TJPs), was investigated in the tumorigenesis of CRC.

Patients And Methods: Adenocarcinoma tissue and paired normal mucosa specimens were resected from surgical specimens of CRC patients and analyzed to determine whether the expression of CL-1 correlated with the clinicopathological factors and to determine the role of CL-1 in the alteration of tight junctions during tumorigenesis.

Recombinant human monoclonal igA antibody against CEA to recruit neutrophils to CEA-expressing cells.

IgA is able to trigger antibody-dependent cellular cytotoxicity (ADCC) by recruiting neutrophils expressing the Fc receptor for the CHalpha chain. We herein describe the preparation of a human recombinant anti-CEA IgA antibody to kill carcinoembryonic antigen (CEA)-expressing tumor cells via ADCC by neutrophils. A single chain Fv (scFv) gene was constructed using a cDNA library of a hybridoma clone that produces a human anti-CEA monoclonal IgG4 (C2-45).

Association between the expression of chemokine receptors CCR7 and CXCR3, and lymph node metastatic potential in lung adenocarcinoma.

Chemokines and their receptors are essential for leukocyte trafficking, and are also involved in cancer metastasis to specific organs. Although the migration of tumor cells into the lymph nodes is an important aspect of cancer, the processes involved are poorly understood. Chemokine receptors CCR7 and CXCR3 have been shown to play an important role in tumor cell migration and lymph node metastasis.

Correlation between lymph node metastasis and the expression of VEGF-C, VEGF-D and VEGFR-3 in T1 lung adenocarcinoma.

Vascular endothelial growth factor (VEGF)-C and VEGF-D influence lymphangiogenesis through the activation of the vascular endothelial growth factor receptor (VEGFR)-3. They have been implicated in lymphatic tumor spread, which is an important prognostic factor in patients with non-small cell lung carcinoma (NSCLC). Whether or not the expression of VEGF-C, -D, and VEGFR-3 correlates with clinicopathological factors in patients with T1 lung adenocarcinoma was analysed.

Selective up-regulation of claudin-1 and claudin-2 in colorectal cancer.

Background: To understand the molecular and morphological alterations in the tight junction in colorectal cancer (CRC) tissues, the expression of eight tight junction proteins in normal and cancer colorectal tissues were compared.

Patients And Methods: Adenocarcinoma tissues and paired normal mucosa were resected from surgical specimens of CRC patients. The expression of occludin, ZO-1, ZO-2, and claudin-1 -5 was analyzed at the mRNA level by quantitative reverse transcription-polymerase chain reaction (RT-PCR) and at the protein level by immunohistochemistry.

Cancer-targeting gene therapy using tropism-modified adenovirus.

Gene therapy has the potential to provide highly selective, curative cancer treatments without inducing systemic toxicity. Adenoviral vectors have been extensively used for cancer gene therapy because of their relatively high efficacy of gene transfer. However, gene transduction to cancer cells is limited by the necessity of using adenoviral type 5 vectors.

Sonodynamic therapy of cancer using novel sonosensitizers.

Sonodynamic therapy (SDT) of cancer is based on preferential uptake and/or retention of a sonosensitizing drug (sonosensitizer) in tumor tissues and subsequent activation of the drug by ultrasound irradiation. Ultrasound can penetrate deeply into tissues and can be focused into a small region of a tumor to activate a sonosensitizer. This is a unique advantage in the non-invasive treatment of nonsuperficial tumors when compared to laser light used for photodynamic therapy.

Sonodynamic therapy of cancer using a novel porphyrin derivative, DCPH-P-Na(I), which is devoid of photosensitivity.

To improve the efficacy of sonodynamic therapy of cancer using photosensitizers, we developed a novel porphyrin derivative designated DCPH-P-Na(I) and investigated its photochemical characteristics and sonotoxicity on tumor cells. DCPH-P-Na(I) exhibited a minimum fluorescent emission by excitation with light, compared with a strong emission from ATX-70, which is known to reveal both photo- and sonotoxicity. According to this observation, when human tumor cells were exposed to light in the presence of DCPH-P-Na(I) in vitro, the least phototoxicity was observed, in contrast to the strong phototoxicity of ATX-70.

A fully human chimeric immune receptor for retargeting T-cells to CEA-expressing tumor cells.

Background: Recombinant chimeric immune receptors (CIRs) with anti-CEA specificity can retarget grafted T-cells to CEA-expressing tumors in an HLA-independent manner. To reduce the immunogenicity of conventional CIR in humans, an attempt was made to generate a CIR encoded by all human genes.

Materials And Methods: A single-chain variable fragmented (scFv) antibody gene was prepared from variable region genes of the C2-45 human mAb clone specific for CEA.

Possible applications of antibodies or their genes in cancer therapy.

In this review article the possible applications of anti-tumor-associated antigen (TAA) antibodies in the therapy of cancer have been summarized. First, recombinant monoclonal antibodies (MAbs) are increasingly being used as therapeutic agents, especially in combination with anti-cancer drugs. Second, conjugation of antibody therapy with toxins or radioisotopes offers more therapeutic approaches.

Carcinoembryonic antigen-targeted selective gene therapy for gastric cancer through FZ33 fiber-modified adenovirus vectors.

Purpose: A major problem when using the adenoviral vectors for gene therapy applications is thought to be related to low transduction efficiency in cancer cells or to side effects in normal cells. There is an urgent requirement to improve the specificity of gene delivery in the context of cancer gene therapy.

Experimental Design: We constructed a genetically modified adenovirus incorporating an IgG Fc-binding motif from the Staphylococcus protein A, Z33, within the HI loop (Adv-FZ33).

Expression of hypoxia-inducible factor-1 alpha and its prognostic significance in small-sized adenocarcinomas of the lung.

Objective: To analyze the prognostic value of hypoxia-inducible factor-1 (HIF-1) alpha expression and its correlation with clinicopathologic variables and the expression of vascular endothelial growth factor-A and -C in patients with lung adenocarcinomas of small size.

Methods: The expression of hypoxia-inducible factor-1 alpha was immunohistochemically determined in 78 cases of small-sized adenocarcinoma (maximum dimension < or = 2 cm) using antibody against a recombinant protein corresponding to amino acids 575-780 of hypoxia-inducible factor-1 alpha. Data regarding patient survival, clinicopathologic factors, and immunohistochemical studies of vascular endothelial growth factors were also collected.

IgG isotype conversion of a novel human anti-carcinoembryonic antigen antibody to increase its biological activity.

Background: The IgG isotype of antibodies is very important for their biological functions such as complement-dependent cytotoxicity (CDC) and antibody-dependent cellular cytotoxicity (ADCC). To increase the biological activity of a novel human monoclonal antibody (C2-45) against carcinoembryonic antigen (CEA), we tried to genetically convert its isotype from IgG4 to IgG1.

Materials And Methods: VH and VL genes were cloned from the parental antibody C2-45 (IgG4) and inserted into the pAc-kappa-CH3 expression vector which contained the constant region gene of human IgG1.

Preparation of human IgG and IgM monoclonal antibodies for MK-1/Ep-CAM by using human immunoglobulin gene-transferred mouse and gene cloning of their variable regions.

For antibody-based therapy of cancer, monoclonal antibodies (mAbs) of human origin are superior to mouse, mouse/human chimeric or humanized mAbs, because of their minimum immunogenicity to humans and their efficient collaboration with human effector cells. In the present study, human mAbs were prepared against a pancarcinoma antigen, MK-1 (Ep-CAM), using a genetically-engineered mouse (KM mouse) that contains the human immunoglobulin genes. Spleen cells from KM mice, immunized with recombinant MK-1, were fused with P3-U1 mouse myeloma cells.