Significant role of macrophages in human cancers associated with Epstein-Barr virus (Review).

Epstein-Barr virus (EBV) is a ubiquitous pathogen that was first identified as a human cancer virus. Many human cancers are associated with EBV, and we demonstrated that EBV infects macrophages. Macrophages infected with EBV show a close correlation with many human cancers, and thus more attention must be given to the role of macrophages infiltrating into cancer tissues associated with EBV.

Involvement of NANOG upregulation in malignant progression of human cells.

Previously, we isolated cell lines that display various degrees of transformed phenotypes from a single-cell population of human diploid fibroblasts (RB) containing a large deletion (13q14-22) in one copy of chromosome 13. They included a cell line transfected with SV40 early genes (RBSV), an immortalized cell line (RBI), an anchorage-independent cell line (RBS), and a tumorigenic cell line (RBT). Here, we analyzed gene expression profiles in these cell lines and showed that expression of some fibroblast-specified or mesenchyme-specified genes were downregulated, and those of stem cell-specified genes, including NANOG, were upregulated during malignant progression.

Macrophage involvement in Epstein-Barr virus-related tumors.

Epstein-Barr virus (EBV) is known as a causative agent of Burkitt's lymphoma, nasopharyngeal carcinoma and approximately 10% of stomach carcinoma cases. In other human cancers, EBV gene expression including lytic infection protein detected using in situ hybridization and immunofluorescence staining has been reported. Moreover, the expression and replication of EBV genes in cultured normal macrophages and in histiocytes of Langerhans' cell histiocytosis have been identified.

Downregulation of drs tumor suppressor gene in highly malignant human pulmonary neuroendocrine tumors.

Neuroendocrine tumors in the lung fall into four categories: typical carcinoid tumor (TC), atypical carcinoid tumor (AC), large-cell neuroendocrine carcinoma (LCNEC) and small-cell lung carcinoma (SCLC), in ascending order of malignancy. The drs gene was originally isolated as a suppressor against v-src transformation and was shown to induce apoptosis in human cancer cells. The expression of drs was markedly downregulated in various human cancer tissues and cell lines.

Expression of Epstein-Barr virus in renal cell carcinoma.

There have been few studies regarding the etiology of renal cell carcinoma. To examine the possible involvement of Epstein-Barr virus (EBV) in this disease, 9 renal cell carcinoma (RCC), 2 nephroblastoma (Wilms' tumor) and 2 RCC cell lines were subjected to mRNA in situ hybridization and indirect immunofluorescence staining. Messenger RNA in situ hybridization using BamHIW, EBNA LP, EBNA 2 and EBER1 probes of EBV revealed signals in all the examined samples, although some samples showed weak signals using the EBNA LP probe.

Expression of the Epstein-Barr virus in lymphoproliferative diseases of the lung.

There have been few studies regarding the etiology of lymphoproliferative disorders of the lung. To examine the possible involvement of the Epstein-Barr virus (EBV) in these diseases, EBV mRNAs, proteins and DNA, were detected. Two non-Hodgkin's lymphomas (NHL) originating in the lung, 5 mucosal-associated lymphoid tissue lymphomas (MALT lymphoma) of the lung, 1 lymphoid hyperplasia of the lung and 1 lymphoid interstitial pneumonia (LIP), were subjected to mRNA in situ hybridization, indirect immunofluorescence staining and PCR.

Downregulation of drs mRNA expression is associated with the progression of adult T-cell leukemia/lymphoma.

Although adult T-cell leukemia/lymphoma (ATLL) is initiated by infection with human T-cell leukemia virus (HTLV-1), many other factors are thought to be required for the progression from indolent ATL to aggressive ATLL. The drs gene was originally isolated as a novel suppressor gene of v-src transformation and was shown to induce apoptosis in human cancer cells. To investigate the involvement of drs downregulation in the progression of ATLL, we examined the expression of drs in smoldering, chronic and aggressive ATLL, and found that drs expression was markedly reduced in clinically aggressive ATLL.

Suppression of tumorigenicity, but not anchorage independence, of human cancer cells by new candidate tumor suppressor gene CapG.

Previously, we isolated a series of cell lines from a human diploid fibroblast lineage as a model for multistep tumorigenesis in humans. After passaging a single LT-transfected fibroblast clone, differently progressed cell lines were obtained, including immortalized, anchorage-independent and tumorigenic cell lines. In the present paper, we analysed the gene expression profiles of these model cell lines, and observed that expression of the CapG protein was lost in the tumorigenic cell line.

Down-regulation of ASY/Nogo transcription associated with progression of adult T-cell leukemia/lymphoma.

Adult T-cell leukemia/lymphoma (ATLL) is an aggressive form of human leukemia/lymphoma. Although this disease is initiated by infection with human T-lymphotropic virus type 1 (HTLV-1), many HTLV-1 carriers survive for a long period without aggressive illness, suggesting that other factors may play roles in the progression of ATLL to an aggressive state. However, the mechanism involved in this progression still remains unclear.

Expression of Epstein-Barr virus in Langerhans' cell histiocytosis.

Langerhans' cell histiocytosis (LCH) is a proliferative histiocytic disorder of unknown etiology. We previously reported that Epstein-Barr virus (EBV) infects and proliferates in macrophages, and investigated the possibility that EBV exhibits etiologic effects in LCH. To detect EBV expression, paraffin sections from 17 LCH cases were examined by mRNA in situ hybridization for EBV BamHIW, Epstein-Barr virus nuclear antigen-2 (EBNA2), and Epstein-Barr virus-encoded small nonpolyadenylated RNA (EBER1) sequences, and by indirect immunofluorescence staining for EBNA2, latent membrane protein 1 (LMP1), and BamHIZ-coding leftward-reading frame 1 (BZLF1).

Expression of Epstein-Barr virus in thyroid carcinoma correlates with tumor progression.

There have been few studies regarding cancer progression from differentiated thyroid carcinoma to the undifferentiated one. To examine the possible involvement of Epstein-Barr virus (EBV) in this progression, 10 papillary carcinomas and 11 undifferentiated carcinomas were subjected to mRNA in situ hybridization, indirect immunofluorescence staining, polymerase chain reaction (PCR), and reverse-transcriptase PCR. mRNA in situ hybridization using a BamHIW probe revealed signals in all of the examined samples, although the signal strength was weaker in the papillary carcinomas than in the undifferentiated carcinomas.

Down-regulation of drs mRNA in human prostate carcinomas.

We have previously reported that the drs gene has the ability to suppress transformation by v-src and v-K-ras in the rat cell line F2808. We have also shown that the expression of drs mRNA is markedly reduced in a variety of human cancer cell lines, suggesting that down-regulation of drs mRNA is correlated with the development of human cancers. To clarify the role of the drs gene in prostate carcinogenesis, we examined the expression of the drs gene in 3 normal prostate, 13 prostate carcinoma, 5 benign prostate hyperplasia (BPH), and 2 prostatic intraepithelial neoplasia (PIN) tissue specimens by in situ hybridization and in 3 prostate carcinoma cell lines (PC3, LNCaP, and DU145) and 2 BPH tissues by Northern blot analysis.

Down-regulation of drs mRNA in colorectal neoplasms.

The drs gene was originally isolated as a transformation suppressor gene against the v-src oncogene. Expression of drs mRNA is down-regulated by retroviral oncogenes such as v-src and v-K-ras in the rat cell line F2408. Expression of drs mRNA is also markedly reduced in a variety of human cancer cell lines, including those of carcinomas of the colon, bladder, and ovary, suggesting that down-regulation of drs mRNA is correlated with the development of human cancers.

Suppression of anchorage-independent growth of human cancer cell lines by the TRIF52/periostin/OSF-2 gene.

In searching for genes that suppress the viral transformation of primary cells, we have isolated a number of TRIF (transcript reduced in F2408) genes that are expressed well in primary rat embryo fibroblasts (REFs) but poorly in spontaneously immortalized rat fibroblast cell lines derived from REFs. One of these genes, TRIF52, is a rat homologue of the mouse protein periostin, which is suspected of being involved in oncogenesis. We found here that periostin mRNA expression is markedly downregulated in a variety of human cancer cell lines and human lung cancer tissues.

Expression of drs mRNA in human lung adenocarcinomas.

The drs gene was originally isolated from a rat primary embryo fibroblast cDNA library as a suppressor gene against v-src transformation. We have previously shown that expression of drs mRNA was markedly reduced in a variety of human cancer cell lines, including those of the colon, bladder, and ovary. Furthermore, introduction of drs cDNA by retrovirus vector into these cancer cell lines caused suppression of anchorage-independent growth without affecting cell proliferation.

Association of Epstein-Barr virus with oral cancers.

Epstein-Barr virus (EBV) persists in the epithelial cells of oral mucosa and often replicates on them. EBV is known to be a causative agent of nasopharyngeal carcinoma. We suspect that EBV may be associated with oral cancers, and thus examined EBV expression on 28 tongues and 9 other oral cancers.

Link of a new type of apoptosis-inducing gene ASY/Nogo-B to human cancer.

Although apoptosis plays an essential role in the embryogenesis and homeostasis of multicellular organisms, this mechanism has not yet been fully clarified. We isolated a novel human apoptosis-inducing gene, ASY, which encodes an endoplasmic reticulum-targeting protein without any known apoptosis-related motifs. This gene is identical to the Nogo-B, a splice variant of the Nogo-A which has recently been shown to be an inhibitor of neuronal regeneration in the central nervous system.

Detection of Epstein--Barr virus-determined nuclear antigen-2 mRNA by in situ hybridization.

A mRNA in situ hybridization method was developed to detect mRNA of Epstein--Barr virus-determined nuclear antigen-2 (EBNA2). Strong in situ hybridization signals were detected in EBNA2-transfected cells with the antisense probe but not with the sense probe of this mRNA. Hybridization signals were also found in formalin-fixed paraffin-embedded tissue samples from patients with invasive uterine cervical cancer and with cervical intraepithelial neoplasia.

Expression of Epstein-Barr virus in cutaneous T-cell lymphoma including mycosis fungoides.

Cutaneous T-Cell lymphoma (CTCL) is a non-Hodgkin's lymphoma of unknown pathogenesis. Mycosis fungoides (MF) is a clinically determined subset of CTCL with intensive infiltration of lymphoma cells into the epidermis. To determine whether Epstein-Barr virus (EBV) is associated with these lymphoma cells, we performed mRNA in situ hybridization in 5 cases of CTCL and 7 cases of MF using an RNA probe transcribed from BamHI W fragment of EBV genome.

Down-regulation of drs mRNA in human colon adenocarcinomas.

We have previously reported that the drs gene, whose mRNA expression is down-regulated by retroviral oncogenes such as v-src and v-K-ras, has the ability to suppress transformation by v-src and v-K-ras in the rat cell line F2408. We have also isolated a human homolog of this gene (h-drs) and shown that expression of h-drs mRNA is markedly reduced in a variety of human cancer cell lines, including those of carcinomas of the colon, bladder, and ovary, suggesting that down-regulation of drs mRNA is correlated with the development of human cancers. To clarify the correlation between down-regulation of the drs gene and malignant tumor formation in human cancer tissues, we examined expression of drs mRNA in human normal tissues, colon adenoma, and adenocarcinoma tissues by in situ hybridization.

Proper use of serum antibody titres against Epstein-Barr virus in nasopharyngeal carcinoma: IgA/virus capsid antigen for diagnosis and EBV-related nuclear antigen-2 for follow-up.

Sera from patients with nasopharyngeal carcinoma (NPC) show high titres of IgA antibodies to Epstein-Barr viral capsid antigen (IgA/VCA). We reported previously that the serum titres for Epstein-Barr virus-related nuclear antigen-2 (EBNA2) correlated with NPC patients' prognosis. To investigate which is better for diagnosing NPC and predicting patient prognosis, the titration of serum IgA/VCA or EBNA2, we examined the same serum titres.

Epstein-Barr virus (EBV) genes expression in cervical intraepithelial neoplasia and invasive cervical cancer: a comparative study with human papillomavirus (HPV) infection.

To elucidate a causative role of Epstein-Barr virus (EBV) for cervical cancer, presence and expression of EBV genes were examined in 31 cervical carcinomas (ICC), 23 cervical intraepithelial neoplasias (CIN), and 35 normal cervices (NCX). In reverse transcription polymerase chain reaction (RT-PCR) analysis, EBER-1 mRNAwas expressed in 74% (23/31) of ICC, 83% (19/23) of CIN, 37% (13/35) of NCX. LMP-1 was expressed in 52% (16/31) of ICC, 70% (16/23) of CIN, and 23% (8/35) of NCX, and EBNA-2 was expressed in 32% (10/31) of ICC, in 48% (11/23) of CIN, and in 11% (4/35) of NCX.

Expression of Epstein-Barr virus in mesopharyngeal and hypopharyngeal carcinomas.

Epstein-Barr virus (EBV) causes various tumors, including nasopharyngeal carcinoma (NPC). There have been no reports as to whether the carcinogenicity of EBV is restricted to the nasopharynx or extends into the mesopharynx and hypopharynx. We attempted to ascertain the relation between EBV and mesopharyngeal (MPC) and hypopharyngeal carcinomas (HPC).

Expression of latent and replicative-infection genes of Epstein-Barr virus in macrophage.

Unlike other herpesviruses, Epstein-Barr virus (EBV) has not yet been shown to infect macrophages. Six macrophage cultures were isolated from normal and affected samples. Nested polymerase chain reaction revealed the existence of the EBV genome in all these macrophages.