Molecular features linked to the growth-inhibitory effects of gemcitabine on human pancreatic cancer cells.

Although gemcitabine (GEM) is widely used in the treatment of pancreatic cancers, the molecular mechanisms that underlie its anti-tumor effects are not fully understood. To clarify the anti-tumor mechanism(s) of GEM, we studied a human pancreatic cancer cell line, YPK-1, that showed a 50% inhibitory concentration (IC50) of GEM of 6.3 x 10(-3) microg/ml after 72 h of exposure.

IL-2-regulated persistent human herpesvirus-6B infection facilitates growth of adult T cell leukemia cells.

Human herpesvirus-6B (HHV-6B), a causative agent of exanthem subitum, infects human adult T cell leukemia (ATL) cell lines. We established a persistent HHV-6B infection in an ATL cell line, TaY, in the presence of 20 units/ml interleukin-2 (IL-2). The HHV-6B infected culture proliferated with a constant ratio of infected (1%) to the uninfected (99%) cells.

Coexpression of CD40 and CD40 ligand in Epstein-Barr virus-infected T and NK cells and their role in cell survival.

We investigated the role that CD40-CD40 ligand (CD40L) signaling plays in survival of Epstein-Barr virus (EBV)-infected T and NK cells. EBV-infected T and NK cell lines derived from patients with either chronic active EBV infection (CAEBV) or nasal T/NK cell lymphoma, as well as virus-infected peripheral T cells freshly isolated from a patient with CAEBV, were shown to express both CD40 and CD40L on their surface. Apoptosis of these cells was enhanced by blockade of CD40-CD40L signaling by a fusion protein of CD40 and immunoglobulin G (CD40Ig).

Transcriptional profiling of human herpesvirus type B (HHV-6B) in an adult T cell leukemia cell line as in vitro model for persistent infection.

Human herpesvirus 6 (HHV-6), which is present in more than 90% of the human, is known to cause infectious diseases in immuno-compromised patients, e.g., transplant patients.

Evaluation of epstein-barr virus DNA load in gastric mucosa with chronic atrophic gastritis using a real-time quantitative PCR assay.

Purpose: It is hypothesized that Epstein-Barr virus (EBV) has already infected the noncarcinomatous gastric mucosa before carcinogenesis of EBV-associated gastric carcinoma. However, the frequency and distribution of EBV infection in the gastric mucosa of chronic atrophic gastritis (CAG) are still unclear. To clarify these points, we evaluated the EBV DNA load in gastric mucosa with CAG.

Long-term intravenous administration of activated autologous lymphocytes for cancer patients does not induce antinuclear antibody and rheumatoid factor.

The treatment of activated autologous lymphocyte can lead to a potent antitumor effect with destruction of autologous cancer cells, but potential adverse autoimmune effects due to destruction of autologous tissue must also be considered. This study was performed to evaluate whether administration of activated autologous lymphocytes induces autoimmune disease. Patients with advanced cancer, who underwent transfer therapy with activated autologous lymphocytes, were eligible for the study.

Molecular signature linked to acquired resistance to cisplatin in esophageal cancer cells.

To clarify the molecular basis of acquired cisplatin (CDDP) resistance in esophageal squamous cell carcinoma (ESCC), we used cDNA microarray technology. A CDDP-resistant cell line (YES-2/CDDP), which shows a 7.5-fold increase in resistance to CDDP and a 3-fold decrease in CDDP accumulation compared with the parental YES-2 ESCC cell line, was generated from YES-2 by exposure to increased concentrations of CDDP.

Characterization of Epstein-Barr virus (EBV)-positive NK cells isolated from hydroa vacciniforme-like eruptions.

Recently, the involvement of Epstein-Barr virus (EBV) in hydroa vacciniforme (HV)-like eruptions has been suggested. To elucidate the role of EBV in this disease, we isolated EBV-infected cell clones from peripheral blood mononuclear cells (PBMC) and the skin lesions of a patient with HV-like eruptions; cells isolated from PBMC were designated SNK-12, and those from the eruption SNK-11. Both cells expressed CD16, CD56, and HLA-DR and had germline configurations of the T-cell receptor and the immunoglobulin genes, indicating that the cell clones were of NK cell lineage.

Common cytological and cytogenetic features of Epstein-Barr virus (EBV)-positive natural killer (NK) cells and cell lines derived from patients with nasal T/NK-cell lymphomas, chronic active EBV infection and hydroa vacciniforme-like eruptions.

In this study, we describe the cytological and cytogenetic features of six Epstein-Barr virus (EBV)-infected natural killer (NK) cell clones. Three cell clones, SNK-1, -3 and -6, were derived from patients with nasal T/NK-cell lymphomas; two cell clones, SNK-5 and -10, were isolated from patients with chronic active EBV infection (CAEBV); and the other cell clone, SNK-11, was from a patient with hydroa vacciniforme (HV)-like eruptions. An analysis of the number of EBV-terminal repeats showed that the SNK cell clones had monoclonal EBV genomes identical to the original EBV-infected cells of the respective patients, and SNK cells had the type II latency of EBV infection, suggesting that not only the cell clones isolated from nasal T/NK-cell lymphomas but also those isolated from CAEBV and HV-like eruptions had been transformed by EBV to a certain degree.

Quantification of human cytomegalovirus using bronchoalveolar lavage cells in pulmonary complications associated with hematologic neoplasia.

Human cytomegalovirus (CMV) has been recognized as a frequent pathogen involved in interstitial pneumonia (IP), and CMV-IP is a severe and life-threatening complication in the immunocompromised patients. The use of real-time PCR in molecular diagnostics has increased to the point where it is now accepted as the gold standard for detecting a wide variety of templates including viruses. Therefore, we developed a rapid quantification system of CMV using a LightCycler in order to clarify the possible role of CMV reactivation in patients with hematologic neoplasia showing pulmonary complications.

Preferential expansion of Vgamma9-JgammaP/Vdelta2-Jdelta3 gammadelta T cells in nasal T-cell lymphoma and chronic active Epstein-Barr virus infection.

We recently established an Epstein-Barr virus (EBV)-positive gammadelta T-cell line from a nasal T/natural killer (NK)-cell lymphoma (Nagata H, Konno A, Kimura N, Zhang Y, Kimura M, Demachi A, Sekine T, Yamamoto K, Shimizu N: Characterization of novel natural killer (NK)-cell and gammadelta T-cell lines established from primary lesions of nasal T/NK-cell lymphomas associated with the Epstein-Barr virus. Blood 2001, 97:708-713). Subsequently, we established two novel EBV-positive gammadelta T-cell lines from the peripheral blood of patients with chronic active EBV infection.

Human neutrophils isolated from peripheral blood contain Ku protein but not DNA-dependent protein kinase.

Ku protein, a heterodimer of 70kDa (Ku70) and 86kDa (Ku86) polypeptides, is involved in non-homologous DNA end-joining (NHEJ) of DNA double-strand break repair and V(D)J recombination in combination with the catalytic component of DNA-dependent protein kinase (p470). Although Ku protein is known to be ubiquitously present in eukaryotic cells, it was previously reported to be absent in mature neutrophils. Using a mixture of protease inhibitors in the isolation procedure of neutrophils from human peripheral blood, we were able to detect Ku in the neutrophils by immunoblot and flow-cytometric analyses.

Inhibition of human telomerase enhances the effect of the tyrosine kinase inhibitor, imatinib, in BCR-ABL-positive leukemia cells.

Purpose: Telomerase is a ribonucleoprotein enzyme that maintains protective structures at the ends of eukaryotic chromosomes. Earlier findings have supported an association between progressive telomere shortening in the chronic phase of chronic myelogenous leukemia and the up-regulation of telomerase activity occurring late in the evolution of the disease. We examined the impact of telomerase inhibition by dominant negative-human telomerase reverse transcriptase (DN-hTERT) on the biological features of BCR-ABL-transformed cells.