Biomedical subjects

S Kamihira

Publications and source records attributed to S Kamihira.

At least 19 recordsLinked to original sources

PubMed2001

Breast cancer resistance protein directly confers SN-38 resistance of lung cancer cells.

Breast cancer resistance protein (BCRP), an ABC half-transporter, is overexpressed in cancer cell lines selected with doxorubicin/verapamil, topotecan, or mitoxantrone. BCRP-overexpressing cells show cross-resistance to camptothecin derivatives such as irinotecan, SN-38 (the active metabolite of irinotecan), and topotecan. To test whether BCRP confers SN-38 resistance, we selected two SN-38 resistant sublines from PC-6 human small-cell lung cancer cells by SN-38, and then characterized these cells. Compared to PC-6 cells, the resistant sublines PC-6/SN2-5 and PC-6/SN2-5H were approximately 18- and 34-fold resistant, respectively. The intracellular SN-38 accumulation was reduced in the sublines, and BCRP mRNA was overexpressed in proportion to the degree of SN-38 resistance. These findings suggest that BCRP confers SN-38 resistance in the sublines. To confirm this hypothesis, PC-6/SN2-5 cells were transfected with antisense oligonucleotides complementary to portions of BCRP mRNA. The antisense oligonucleotides significantly suppressed BCRP mRNA expression, and enhanced SN-38 sensitivity in the subline. These data indicate that BCRP is directly involved with SN-38 resistance, by efflux transport of SN-38.

ATP Binding Cassette Transporter, Subfamily G, Mem↗

PubMed2001

Soluble Fas (APO-1/CD95) isoform in adult T-cell leukemia.

Fas (APO-1/CD95) consists mainly of 2 isoforms, membrane-anchored (mFas) and soluble (sFas), both of which can mediate apoptosis through the Fas-signalling process, not only in normal but also in leukemia T-cells. This suggests that aberrant expression of either mFas or sFas may affect the natural history of T-cell neoplasms, such as adult T-cell leukemia (ATL). For studying the tumor biology related to Fas-mediated apoptosis, ATL cells with up-regulated Fas proteins and its mRNAs are convenient and useful for understanding apoptotic oncology as it occurs in nature. Most attention, so far, has been focused on mFas, and little is known about neoplasms from the viewpoint of sFas. Accordingly, we herein review and discuss the biological and clinical implications of sFas in ATL.

Apoptosis↗

PubMed2000

Correlation of urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG), a biomarker of oxidative DNA damage, and clinical features of hematological disorders: a pilot study.

The 8-hydroxy-2'-deoxyguanosine (8-OHdG), presently the most popular marker for oxidative DNA damage, level has been reported to be elevated in patients with various malignancies. In the present study, urinary 8-OHdG was examined in 44 patients with hematological disorders (13 malignant lymphoma, 11 adult T cell leukemia/lymphoma (ATL), 10 acute leukemia, and 10 myelodysplastic syndrome (MDS)) by an enzyme-linked immunosorbent assay. The pre-therapy level of urinary 8-OHdG in ATL patients was significantly elevated compared with normal controls (25.3+/-12.9 vs. 11.9+/-7.3 ng/mg, P<0.05). Although patients with lymphoma, acute leukemia and MDS also showed higher urinary 8-OHdG levels than normal controls, the differences were not significant. However, two patients with refractory anemia with excess blasts in transformation (RAEB-t) having extreme monocytosis and neutrophilia showed exceptionally high urinary 8-OHdG levels (161.0 and 218.9 ng/mg). Urinary 8-OHdG excretion increased transiently with chemotherapy, and this fluctuation was significant irrespective of the disorder (P<0.05). Interestingly, lymphoma patients with high LDH, advanced stage, poor performance status or International Prognostic Index (IPI) of high/high-intermediate risk had significantly elevated urinary 8-OHdG levels (P<0.05-<0.001). These latter results suggest that urinary 8-OHdG may be a reliable prognostic marker in lymphoma patients and should encourage large scale and long term follow up studies.

8-Hydroxy-2'-Deoxyguanosine↗

PubMed2000

Minimally differentiated acute myeloid leukemia (AML-M0) with extensive erythrophagocytosis and del(20)(q11) chromosome abnormality.

We describe an 84-year-old woman who presented severe pancytopenia and 36.6% of blasts accompanied with erythrophagocytosis in the bone marrow. According to cytochemical and immunological findings, a diagnosis of minimally differentiated acute myeloid leukemia (AML-M0) was established. Cytogenetic analysis revealed del(20)(q11) which were previously reported for one case each of ALL and MDS associated with cytophagocytosis by blasts, leading us to speculate a disease entity. Interestingly, a high expression of mRNA of TNF-alpha was detected by RT-PCR on the bone marrow mononuclear cells.

Acute Disease↗

PubMed2000

Expression and phosphorylation status of retinoblastoma protein in adult T-cell leukemia/lymphoma.

The deletion or hyperphosphorylation of the retinoblastoma protein (pRB), is reported to progress various tumors. But its relevance to adult T-cell leukemia/lymphoma (ATL) remains to be elucidated. To better understand the role of pRB in ATL, we examined the expression and phosphorylation status of pRB in three ATL cell lines and 43 clinical samples, eight peripheral blood samples and 35 lymph node samples, from patients with ATL by Western blotting. In addition, 30 lymph node sections were also evaluated immunohistochemically. As a result, Western blotting analysis revealed that the pRB in the ATL cell lines was in the hyperphosphorylated, but that in 39 of 43 clinical samples, pRB was exclusively in the hypophosphorylated form. Four peripheral blood samples were negative for pRB. Immunohistochemistry revealed that the lymph nodes of all of 30 patients tested were positive for pRB at various staining levels, weak, mild, and strong. But weak expression may be essentially negative for pRB function. Patients with weak pRB expression in their lymph nodes lived significantly shorter lives than those with mild expression. Surprisingly, patients with strong expression also showed a significantly worse prognosis than those with mild expression. Although only the absence of pRB expression was considered previously to be indicative of RB functional loss, it has been reported recently that overexpression of pRB is correlated with progression of disease in patients with advanced bladder carcinoma or follicular lymphoma. These findings indicate that pRB controls tumor proliferation not only as a cell cycle regulator but also by other mechanisms, possibly through the inhibition of apoptosis, as suggested by recent findings in an osteosarcoma cell line, Saos-2. In conclusion, pRB may play an essential role in its hypophosphorylated form for progression of ATL, as well as a cell cycle promoter in hyperphosphorylated or negative/excessive reduced form.

Adult↗

PubMed2000

Qualitative and quantitative characterization of Fas (CD95) expression and its role in primary human acute leukemia cells.

Fas antigen, a cell surface molecule, directly mediates apoptosis, and is expressed on a limited number of human tissues. Blood or bone marrow samples from patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL) and mixed leukemia were examined qualitatively and quantitatively for the expression of Fas as well as its function using flow cytometry and the annexin V staining method. Fas expression was flow cytometrically unimodal with heterogeneous density, and showed quantitatively characteristic features in different diseases: undetectable in mixed leukemia, faint to weak in ALL, low in M0 and M1, and variable (low to strong) in M2, M3, M4, and M5. Both the full-length and the alternatively spliced truncated mRNAs were detected constitutively even in acute leukemia cells with qualitatively negative and quantitatively faint Fas, and the band density of the former transcripts detected by RT-PCR was correlated with the level of expression of the Fas protein. Short-term culturing of freshly isolated leukemia cells gave rise to an increase of Fas density. In acute leukemia cells, the apoptosis induced by anti-Fas MoAb was compared with that induced by etoposide (a topoisomerase II inhibitor). We found that fresh ALL and AML cells were resistant to the anti-Fas IgM antibody, while etoposide could trigger apoptosis in all types of leukemia tested. The combined effects of the anti-Fas MoAb and etoposide were not always synergistic. These results suggest that Fas is a biological marker for characterizing ALL and AML cells, and provide insight into creating a new therapeutic modality using cytotoxic drugs and cytokines together with modulation of Fas.

Acute Disease↗

PubMed2000

Lactacystin activates FLICE (caspase 8) protease and induces apoptosis in Fas-resistant adult T-cell leukemia cell lines.

Lactacystin (LC) is a specific inhibitor of the proteasome, and has recently been shown to induce apoptosis in certain cell lines. In the present study, we established Fas-resistant adult T-cell leukemia (ATL) cell subclones RSO4 and RST1 from their parental Fas-sensitive cell lines SO4 and ST1, and examined whether LC can overcome Fas resistance. LC completely inhibited proteasome function as determined by a peptidyl-MCA substrate (LLVY-MCA and LLE-MCA), and induced apoptosis in these cell lines irrespective of Fas sensitivity at low concentrations (approximately 10 microM). LC induced the activation of caspase 3 (CPP32/Yama) and caspase 6 proteases in an identical manner to Fas-mediated apoptosis. Moreover, LC induced the activation of caspase 8 (FLICE) protease, which is the initiator of the Fas-mediated apoptotic cascade. Synthesized proteasome inhibitory peptide MG-115 (ZLLnV-CHO) also induced apoptosis in these cell lines. These results indicated that proteasome inhibitors overcome Fas-resistance by bypassing the proximal part of the Fas signal. Inhibition of the proteasome function may be a new strategy for the treatment of ATL.

Acetylcysteine↗

PubMed2000

Penetration of clinical isolates of Pseudomonas aeruginosa through MDCK epithelial cell monolayers.

Pseudomonas aeruginosa causes both invasive (bacteremic) and chronic noninvasive infections. A simple in vitro system to screen P. aeruginosa clinical isolates for their capacity to penetrate MDCK cell monolayers has been developed. By means of this system, P. aeruginosa clinical isolates, including 32 blood and 45 respiratory isolates, were examined. When monolayers were infected with 3.5x107 cfu of bacteria, significantly more blood (93.7%) than respiratory (54.4%) isolates (P<.001) were detected in the basolateral medium after 3 h. Penetration ability was usually independent of cytotoxicity. Only 8 (4 blood and 4 respiratory) isolates were cytotoxic, possessed exoU, and passed through the monolayer after epithelial cell death, associated with a marked drop in transepithelial electrical resistance. Conversely, noncytotoxic isolates with high penetration ability but without severe epithelial damage were invasive. This system is well suited for screening clinical isolates and their mutants for specific genes conferring the invasiveness phenotype.

Animals↗

PubMed2000

Birth cohort effects on incidence of lung cancers: a population-based study in Nagasaki, Japan.

Smoking prevalence remains high (around 60%) among Japanese males, but smoking initiation among males born in the 1930s decreased by approximately 10% due to economic difficulties following World War II. The present study was designed to examine whether this temporary decline in smoking initiation influenced the subsequent incidence of lung cancers, especially adenocarcinoma. Trends of lung cancer incidence by histological type in both sexes were investigated using data from the population-based cancer registry in Nagasaki, Japan, from 1986 through 1995. During this period, 5668 males and 2309 females were diagnosed as having lung cancer, and the overall incidence of lung cancers among both sexes remained stable. However, males aged 55 - 59 years showed a decrease in the age-specific incidence of adenocarcinoma and squamous-cell carcinoma (P < 0.05 and P < 0.01, respectively). In birth cohort analyses, the incidence of adenocarcinoma and squamous-cell carcinoma was lower in the 1935 - 1939 birth male cohort than in the successive cohorts. The incidence of lung cancers among females with low smoking prevalence did not change with birth cohort. The low smoking initiation among the 1935 - 1939 birth male cohort appeared to have resulted in a decreased incidence of adenocarcinoma and squamous cell carcinoma among middle-aged Japanese males. The present study suggests that smoking prevention has an effect in reducing the incidence of lung adenocarcinoma, as well as squamous-cell carcinoma, among smokers.

Adenocarcinoma↗

PubMed2000

In vitro activity of telithromycin (HMR3647), a new ketolide, against clinical isolates of Mycoplasma pneumoniae in Japan.

The in vitro activity of telithromycin (HMR3647), a new ketolide, against Mycoplasma pneumoniae was determined by the broth microdilution test using 41 clinical isolates obtained in Japan, as compared with those of five macrolides (erythromycin, clarithromycin, roxithromycin, azithromycin, and josamycin), minocycline, and levofloxacin. Telithromycin was less potent than azithromycin, but it was more active than four other macrolides, minocycline, and levofloxacin; its MICs at which 50 and 90% of the isolates tested were inhibited were both 0.00097 microg/ml, justifying clinical studies to determine its efficacy for treatment of M. pneumoniae.

Anti-Bacterial Agents↗

PubMed2000

[Characteristics of plasma DNA and its application for detection of K-ras gene mutation].

DNA diagnosis is useful and significant for clinical oncology, but its use is limited due to a difficulty in preparing tumor-derived DNA materials. To overcome this problem, we investigated the characterization of plasma DNA and it application to successfully detecting K-ras mutation at codon 12 in normal persons, hematopoietic neoplasms, and solid tumors. The range of plasma DNA in each group was 15.8 +/- 5.2 ng/ml, 43.3 +/- 29.8 ng/ml, and 26.8 +/- 17.0 ng/ml, respectively. The ranges in patients with solid tumor were gradually decreased to the normal level of around 15 ng/ml in 3 weeks postoperatively. Plasma DNAs consisted of about 200 bp DNA fragmentation and were convenient for PCR amplification of K-ras gene. The mutation at codon 12 by PCR-RFLP analysis was detected in 13(27%) of 49 patients with solid tumors such as pancreatic cancer, breast cancer, colon cancer, and gastric cancer. The diagnostic specificity was 100%. Serial observations by the PCR-RFLP analysis revealed disappearance of the mutant K-ras about 7 days after successful curative surgery in a patient with gastric cancer.

Adult↗

PubMed2000

[Activities of antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. Levofloxacin--Surveillance Group].

The surveillance study was conducted to determine the antimicrobial activity of fluoroquinolones (ofloxacin, levofloxacin, ciprofloxacin, tosufloxacin) and other 20 antimicrobial agents against 5,180 clinical isolates obtained from 26 medical institutions during 1998 in Japan. The resistance to fluoroquinolones was remarkable in Enterococci, methicillin-resistant staphylococci and Pseudomonas aeruginosa from UTI. However, many of the common pathogens such as Streptococcus pneumoniae including penicillin-resistant isolates, methicillin-susceptible Stahylococcus aureus, Moraxella catarrhalis, the family of Enterobacteriaceae, Haemophilus influenzae including ampicillin-resistant isolates have been kept to be susceptible to fluoroquinolones. About 90% of P. aeruginosa isolates from RTI were susceptible to fluoroquinolones. In conclusion, the results from this surveillance study suggest that fluoroquinolones are useful in the treatment of various bacterial infections including respiratory infections.

Anti-Infective Agents↗

PubMed2000

Real-time polymerase chain reaction for quantification of HTLV-1 proviral load: application for analyzing aberrant integration of the proviral DNA in adult T-cell leukemia.

We describe the establishment of a real-time polymerase chain reaction (PCR) assay for the quantitative estimation of human T-cell leukemia virus type 1 (HTLV-1) proviral load using a LightCycler Technology (Roche Diagnostics, Mannheim, Germany) instrument. Proviral DNA level represents a measure of the integrated viral genome in host cells, so we applied this technique to evaluate the tumor burden in adult T-cell leukemia (ATL) patients with aberrant integration patterns of HTLV-1 detected by standard Southern blot hybridization (SBH) analysis. In 14 of our 15 ATL cases with 2 or more bands detected by SBH analysis, the ATL cells were shown to harbor multiple copies of the provirus within 1 ATL cell. This result suggests the usefulness of real-time PCR quantification for the study of the relationship between ATL pathology and HTLV-1-induced pathogenesis.

DNA, Viral↗

PubMed1999

Fas-resistance in ATL cell lines not associated with HTLV-I or FAP-1 production.

A preventive role for human T-cell leukemia virus type-I (HTLV-I) and Fas-associated phosphatase-1 (FAP-1) in Fas-mediated apoptosis has been reported in HTLV-I-infected cells. In the present study, we examined whether these molecules increased during the acquisition of Fas-resistance in adult T-cell leukemia (ATL) cell lines. SO4, ST1 and KK1 are Fas-sensitive ATL cell lines, and produce small amounts of HTLV-I in vitro. Although their subclones RSO4 and RST1 are completely Fas-resistant, they produced an equivalent amount of HTLV-I to SO4 and ST1. Moreover, FAP-1 mRNA was not detected in these cell lines irrespective of Fas sensitivity. Thus, Fas resistance in ATL cells was not directly associated with the increased production of HTLV-I or FAP-1.

Antibodies, Monoclonal↗

PubMed1999

Adult T-cell leukemia cells over-express the multidrug-resistance-protein (MRP) and lung-resistance-protein (LRP) genes.

Adult T-cell leukemia (ATL) is a T-cell malignancy caused by human T-cell-leukemia-virus-I (HTLV-I) infection. ATL comprises 4 clinical forms: acute, chronic, smoldering and lymphoma types. ATL is usually resistant to conventional chemotherapy and has a relatively poor prognosis; however, the resistance mechanisms remain undetermined. To explore the multidrug-resistance (MDR) mechanisms of ATL, we examined the expression and functional activity of MDR-related genes in peripheral-blood mononuclear cells (PBMC) from ATL patients by semi-quantitative RT-PCR and FACScan with calcein-AM. PBMC from ATL patients expressed similar or higher levels of MRP, LRP and cMOAT mRNAs, as compared with normal PBMC. In normal controls and ATL patients, MDR1 mRNA expression was undetectable in this study. PBMC from acute and chronic ATL patients expressed significantly higher levels of MRP and LRP mRNA than did normal PBMC (p < 0.01 and p < 0.05 respectively). In chronic ATL, positive correlations were apparent between levels of MRP and LRP mRNA expression (r = 0.759, p = 0.018), and between each mRNA level and the absolute number of abnormal lymphocytes in peripheral blood. Probenecid, an inhibitor of the MRP pump, significantly increased the accumulation of calcein in PBMC from 3 chronic ATL patients. Our findings suggest that the MRP and LRP genes in ATL are often activated by HTLV-I infection and may confer MDR of ATL cells in vivo. Combined chemotherapy with inhibitors of these MDR genes may be promising in the treatment of ATL.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1999

Fas gene mutation in the progression of adult T cell leukemia.

Fas antigen (Apo-1/CD95) is an apoptosis-signaling cell surface receptor belonging to the tumor necrosis factor receptor superfamily. Adult T cell leukemia (ATL) cells express Fas antigen and show apoptosis after treatment with an anti-Fas monoclonal antibody. We established the ATL cell line KOB, which showed resistance to Fas-mediated apoptosis, and found that KOB expressed two forms of Fas mRNA, the normal form and a truncated form. The truncated transcript lacked 20 base pairs at exon 9, resulting in a frame shift and the generation of a premature stop codon at amino acid 239. The same mutation was detected in primary ascitic cells and peripheral blood cells. The mutation was not detected in lymph node cells, however, although all of the primary ATL cells were of the same clonal origin. A retroviral-mediated gene transfer of the truncated Fas to Jurkat cells rendered the cells resistant to Fas-mediated apoptosis, suggesting a dominant negative interference mechanism. These results indicate that an ATL subclone acquires a Fas mutation in the lymph nodes, enabling the subclone to escape from apoptosis mediated by the Fas/Fas ligand system and proliferate in the body. Mutation of the Fas gene may be one of the mechanisms underlying the progression of ATL.

Aged↗

PubMed1999

Qualitative and quantitative characterization of Fas (APO-1/CD95) on leukemic cells derived from patients with B-cell neoplasms.

Expression density and function of Fas (APO-1/CD95) on malignant B-cells, an antigen thought responsible for abnormal tumor biology, remains to be fully understood. Fifty-five cases with B-cell neoplasms of acute lymphoblastic leukemia (ALL), chronic lymphocytic leukemia (CLL), hairy cell leukemia (HCL), B-cell malignant lymphoma (ML), and myeloma (MM) were studied for qualitative and quantitative expression and function of Fas using flow cytometry and annexin-V staining methods. Fas expression was flow cytometrically unimodal with heterogeneous density and showed quantitatively characteristic features among different diseases; weak in ALL, faint in CLL, moderate in HCL, and strong in ML, respectively. Not only full-length but also alternatively spliced truncated mRNAs were detected even in leukemic B-cells with qualitatively faint or negative Fas, and then band density of the former transcripts by RT-PCR was correlated to the Fas protein expression level. Short-term culture of freshly isolated cells gave rise to increases of Fas density and susceptibility for apoptosis, suggesting that the mRNA and inducible Fas are functional at least in vitro. These results show that Fas is a biological marker for characterizing B-cell neoplasms reflecting various stages of B-cell ontogeny and may have clinical utility as a therapeutic strategy.

Apoptosis↗

PubMed1999

Multi-clonal expansion of unique human T-lymphotropic virus type-I-infected T cells with high growth potential in response to interleukin-2 in prodromal phase of adult T cell leukemia.

We established a simple IL-2-dependent colony-forming assay for T cells infected with human T-lymphotropic virus type-I (HTLV-I). IL-2-dependent cell lines were subsequently established by expanding individual colonies in liquid cultures. Lymphocyte-rich fractions were prepared from 31 HTLV-I carriers, 12 patients with smoldering ATL, 11 chronic ATL, 12 crisis ATL and 10 acute ATL. Primary colonies of CD4+ p19+ T cells were formed in all cases of carriers, smoldering and chronic ATL, and in 10 of 12 crisis cases. In contrast, no colony was formed from cells of patients with acute ATL. The rate of establishment of cell lines in HTLV-I carriers was significantly lower than that in patients of prodromal phase ATL. Cell lines established from cells of three prodromal cases were clonally identical to the parent ATL cells, while others had clonally distinct cell lines. Our results indicated the presence of four components of HTLV-I-infected T cells: (1) normal carrier T cells capable of forming colonies but not cell lines; (2) pre-malignant T cells capable of forming colonies as well as cell lines; (3) malignant T cells capable of forming colonies as well as cell lines; (4) fully malignant T cells unresponsive to IL-2. Our results suggest the presence of a multiclonal expansion of unique T cells in the prodromal phase of ATL, which have a high growth potential in response to IL-2. The coexistence of multiclonality with a dominant ATL clone may be closely related to the underlying pathology in HTLV-I leukemogenesis.

Case-Control Studies↗