Lower risk of progression from prediabetes to diabetes with health checkup with lifestyle education: Japan Ningen Dock study.

BACKGROUND AND AIMS: To investigate whether the progression from prediabetes to diabetes is lower among those who undertake Ningen Dock (comprehensive health checkups with lifestyle education and doctor's consultation) than those who undertake basic mandatory occupational health checkups. METHODS AND RESULTS: Subjects aged 30-69 years with complete annual data from 2008 to 2012 for either Ningen Dock or basic health checkups were enrolled. Subjects with prediabetes (fasting plasma glucose 100-125 mg/dl or HbA1c 5.7-6.4%) at baseline were selected (14,928 in the comprehensive group and 10,433 in the basic group). The incidence of diabetes (fasting plasma glucose ≥ 126 mg/dl, HbA1c ≥ 6.5% or taking glucose-lowering drugs) and the reduction of risk factors were compared. After 4 years, 3226 cases of diabetes occurred among 25,361 subjects with prediabetes. The incidence of diabetes was lower in the comprehensive group than the basic group (2.9 vs. 3.8 cases/100 person-years, hazard ratio 0.75, 95% confidence interval 0.68-0.81 after adjustment). Moreover, more overweight subjects controlled their body mass index (16.2% vs. 13.2%) and more began a daily exercise habit (11.8% vs. 8.5%) in the comprehensive group than in the basic group. The incidence of diabetes was lower in subjects who could control their weight or start daily exercise at year 1 in the comprehensive group. CONCLUSION: Progression from prediabetes to diabetes was significantly lower in subjects undertaking a comprehensive health checkup with lifestyle education. Lifestyle education at health checkup for people with prediabetes might prevent progression to diabetes by reducing modifiable risk factors.

Long interspersed element-1 is differentially regulated by food-borne carcinogens via the aryl hydrocarbon receptor.

A single human cell contains more than 5.0 × 10(5) copies of long interspersed element-1 (L1), 80-100 of which are competent for retrotransposition (L1-RTP). Recent observations have revealed the presence of de novo L1 insertions in various tumors, but little is known about its mechanism. Here, we found that 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) and 2-amino-3,8-dimethyl-imidazo[4,5-f]quinoxaline (MeIQx), food-borne carcinogens that are present in broiled meats, induced L1-RTP. This induction was dependent on a cellular cascade comprising the aryl hydrocarbon receptor (AhR), a mitogen-activated protein kinase, and CCAAT/enhancer-binding protein ß. Notably, these compounds exhibited differential induction of L1-RTP. MeIQx-induced L1-RTP was dependent on AhR nuclear translocator 1 (ARNT1), a counterpart of AhR required for gene expression in response to environmental pollutants. By contrast, PhIP-induced L1-RTP did not require ARNT1 but was dependent on estrogen receptor α (ERα) and AhR repressor. In vivo studies using transgenic mice harboring the human L1 gene indicated that PhIP-induced L1-RTP was reproducibly detected in the mammary gland, which is a target organ of PhIP-induced carcinoma. Moreover, picomolar levels of each compound induced L1-RTP, which is comparable to the PhIP concentration detected in human breast milk. Data suggest that somatic cells possess machineries that induce L1-RTP in response to the carcinogenic compounds. Together with data showing that micromolar levels of heterocyclic amines (HCAs) were non-genotoxic, our observations indicate that L1-RTP by environmental compounds is a novel type of genomic instability, further suggesting that analysis of L1-RTP by HCAs is a novel approach to clarification of modes of carcinogenesis.

Plasma amino acid profile is associated with visceral fat accumulation in obese Japanese subjects.

UNLABELLED: What is already known about this subject • Asians with metabolic complications associated with obesity, a low body mass index and a low waist circumference have a greater proportion of visceral adipose tissue for a given amount of total body fat compared with Europeans. • Apparent obese humans and obese animal models show an elevation of branched-chain amino acid levels in plasma. • A multivariate logistic regression model of plasma free amino acids has been used to screen for several types of cancers in clinical settings. What this study adds • A specific formula incorporating six amino acid values (Ala, Gly, Glu, Trp, Tyr and branched-chain amino acid) was developed for discrimination of subjects with high visceral fat area by multivariate logistic regression analyses. • The generated amino acid formula was strongly correlated with visceral fat area in both apparent and non-apparent obese subjects. • Measuring plasma free amino acids can be used to distinguish the non-apparent visceral obesity in clinical settings in Asian populations. SUMMARY: Metabolic complications associated with obesity are becoming more common among Japanese subjects. However, visceral fat accumulation is not always apparent by measuring body mass index (BMI) or waist circumference in Asian populations because of the physiological characteristics particular to those ethnicities. Excess visceral fat accumulation raises the odds ratio for developing cardiovascular disease. Thus, high-throughput determination of the amount of abdominal adipose tissue is necessary. We hypothesized that accumulating visceral fat alters the peripheral amino acid profile and that a multivariate logistic regression model of plasma free amino acids can distinguish visceral obesity. A total of 1449 Japanese subjects (985 males and 464 females) who had undergone a comprehensive health screening were enrolled in this study. The visceral fat area was determined using computed tomography imaging, and a plasma free amino acid index to identify high visceral fat areas (≥100 cm(2) ) was developed. The sensitivity and specificity values of the generated amino acid index were 80% and 65%, respectively. In particular, the sensitivity of the generated index to identify subjects with non-apparent visceral obesity (BMI < 25 kg m(-2) ; visceral fat area ≥ 100 cm(2) ) was much greater than that of the waist circumference (73% vs. 46%, respectively). This index's high sensitivity and specificity may be the result of specific alterations in the patients' amino acid profiles, which were specifically correlated with the visceral fat areas and not with subcutaneous fat areas. This profile can be used as a predictor of elevated visceral obesity and a risk assessment tool for metabolic complications in Asian populations.

HIV-1 Vpr induces ATM-dependent cellular signal with enhanced homologous recombination.

An ATM-dependent cellular signal, a DNA-damage response, has been shown to be involved during infection of human immunodeficiency virus type-1 (HIV-1), and a high incidence of malignant tumor development has been observed in HIV-1-positive patients. Vpr, an accessory gene product of HIV-1, delays the progression of the cell cycle at the G2/M phase, and ATR-Chk1-Wee-1, another DNA-damage signal, is a proposed cellular pathway responsible for the Vpr-induced cell cycle arrest. In this study, we present evidence that Vpr also activates ATM, and induces expression of gamma-H2AX and phosphorylation of Chk2. Strikingly, Vpr was found to stimulate the focus formation of Rad51 and BRCA1, which are involved in repair of DNA double-strand breaks (DSBs) by homologous recombination (HR), and biochemical analysis revealed that Vpr dissociates the interaction of p53 and Rad51 in the chromatin fraction, as observed under irradiation-induced DSBs. Vpr was consistently found to increase the rate of HR in the locus of I-SceI, a rare cutting-enzyme site that had been introduced into the genome. An increase of the HR rate enhanced by Vpr was attenuated by an ATM inhibitor, KU55933, suggesting that Vpr-induced DSBs activate ATM-dependent cellular signal that enhances the intracellular recombination potential. In context with a recent report that KU55933 attenuated the integration of HIV-1 into host genomes, we discuss the possible role of Vpr-induced DSBs in viral integration and also in HIV-1 associated malignancy.

Antitumor effect of beta2-microglobulin in leukemic cell-bearing mice via apoptosis-inducing activity: activation of caspase-3 and nuclear factor-kappaB.

We have reported previously that beta2-microglobulin (beta2m) induces apoptosis in leukemic cells in vitro, and that an interaction between beta2m and HLA class I antigen induces apoptosis. Here we examined whether beta2m can induce apoptosis in leukemic cells in vivo and whether it has an antitumor effect in tumor-bearing mice. Daily administration of 50 or 250 microg of beta2m induced apoptosis and an antitumor effect on K562 leukemia cell-bearing mice in the same manner as tumor necrosis factor-alpha. In tumor tissues in beta2m-treated mice, both caspase-3 and nuclear factor-kappaB (NF-kappaB) were stained more strongly than in control mice by anti-caspase-3 and anti-NF-kappaB p65/Rel A polyclonal antibodies. We also observed the in vivo immunological effects of beta2m on lymphoid and hematopoietic organs, such as thymus, bone marrow, Peyer's patches, liver, and spleen in normal mice. Using antibodies against caspase-3 and NF-kappaB, immunohistochemical staining showed that no specific tissues were damaged or stained in normal mice. We conclude that beta2m stimulates caspase-3 and NF-kappaB pathways to induce apoptosis, making it a useful approach to a new therapy for leukemia.

C-type natriuretic peptide is synthesized and secreted from leukemia cell lines, peripheral blood cells, and peritoneal macrophages.

OBJECTIVE: C-type natriuretic peptide (CNP) is the third member of the natriuretic peptide family. Cultured endothelial cells secrete CNP, and its secretion rate from the endothelial cells is augmented by lipopolysaccharide, interleukin-1beta, and tumor necrosis factor-alpha, which participate in the pathophysiology of inflammation. In this study, we investigated the regulation of CNP secretion from monocytes and macrophages to estimate its contribution to the progression of inflammation. MATERIALS AND METHODS: CNP secretion rates from two human leukemia cell lines (THP-1 and HL-60), human peripheral blood lymphocytes, granulocytes, monocytes, monocyte-derived macrophages, and mouse peritoneal macrophages were measured under conditions with or without stimulation. Immunoreactive CNP levels in the culture media of these cells were measured by a specific radioimmunoassay. RESULTS: The secretion rates of CNP from THP-1 and HL-60 cells were augmented according to the degree of their differentiation into macrophage-like cells under the stimulation with phorbol ester. Peripheral blood monocytes also increased the CNP secretion rate after their differentiation into macrophages. Retinoic acid elicited synergistic effects on the CNP secretion rate from HL-60 cells when administered with lipopolysaccharide, interferon-gamma, interleukin-1beta, tumor necrosis factor-alpha, or phorbol ester. In contrast, the phorbol ester-stimulated CNP secretion rate from THP-1 cells was suppressed with dexamethasone, which inhibits monocyte differentiation into macrophage. CONCLUSIONS: The secretion rate of CNP from monocytes was shown to be regulated based on the degree of their differentiation. This study provides evidence that the monocyte/macrophage system is one of the sources of CNP, especially under inflammatory conditions.

A new apoptotic pathway for the complement factor B-derived fragment Bb.

Apoptosis is involved in both the cellular and humoral immune system destroying tumors. An apoptosis-inducing factor from HL-60 myeloid leukemia cells was obtained, purified, and sequenced. The protein found has been identified as a human complement factor B-derived fragment Bb, although it is known that factor B is able to induce apoptosis in several leukemia cell lines. Monoclonal antibodies against fragment Ba and Bb inhibited the apoptotic activity of factor B. When the purified fragment Bb was used for apoptosis induction, only the anti-Bb antibody inhibited Bb-induced apoptosis, and not the anti-Ba antibody. The apoptosis-inducing activity was found to be enhanced under conditions facilitating the formation of Bb. Blocking TNF/TNFR or FasL/Fas interactions did not interfere with the factor B-induced apoptosis. CD11c (iC3bR) acts as the main subunit of a heterodimer binding to fragment Bb in the apoptosis pathway, and the factor B-derived fragment Bb was found to possess the previously unknown function of inducing apoptosis in leukemic cells through a suicide mechanism of myeloid lineage cells during the differentiation stage.

Oxidative stress as a necessary factor in room temperature-induced apoptosis of HL-60 cells.

HL-60 cells undergo apoptosis when placed at room temperature (RT) [Shimura et al. (1997) FEBS Lett. 417, 379-384]. We report that superoxide anion radical, one of the reactive oxygen species (ROS), was produced after RT treatment. Affinity blot analysis with a biotinylated YVAD-CHO detected the generation of processed peptides with molecular masses of 15-25 kDa. Activation of such an ICE-like protease was completely abolished by N-acetylcysteine and exogenously expressed Bcl-2, known as antioxidants. We concluded that oxidative stress was a critical factor in the signal cascade of the apoptosis. Western blot analysis and experiments using tetrapeptide inhibitors suggested that caspases-1, -3, -4, -6, and -9 did not have an essential role in the apoptotic cascade. It is interesting that cyclosporin A (CsA) blocked RT-induced apoptosis with an inhibition of cytochrome c release from mitochondria. CsA, however, generated a significant amount of ROS with considerable reduction of mitochondrial membrane potential, implying that oxidative stress was one necessary factor for RT-induced apoptosis. It is also likely that mitochondrial membrane potential and the release of apoptotic factors from cytoplasm are differently regulated. Taken together with the reports that some Burkitt lymphoma cells showed apoptosis when exposed at low temperature followed by rewarming, and that hepatocytes or liver endothelial cells are susceptible to cold-induced apoptosis through the ROS function, we propose that studying the mechanism of RT-induced apoptosis of HL-60 cells may provide a therapeutic strategy for pathological conditions involving ROS, such as neurodegenerative diseases and ischemia.

Improved gene transfer to neuroblastoma cells by a monoclonal antibody targeting RET, a receptor tyrosine kinase.

Receptor-mediated gene transfer is an effective strategy among nonviral vector systems. It is, however, crucial to develop various types of monoclonal antibodies satisfying both the binding specificity for cell targeting and the capacity of endocytosis required for gene transfer. In the present study, we generated a novel monoclonal antibody (NBL-1) to RET, a receptor tyrosine kinase expressed in both neuroblastoma cells and cells present in substantia nigra, a responsive locus of Parkinson's disease. NBL-1, when added to the culture medium of the neuroblastoma cells, was incorporated by endocytosis in a wortmannin-sensitive manner. Using a biotinylated NBL-1 complexed with plasmid DNAs based on electrostatic interaction through avidin-conjugated polylysines, exogenous luciferase genes were expressed in neuroblastoma cells at a more than 10-fold higher level. The expression level of the gene based on NBL-1 was comparable to that obtained by a geneporter system, an improved nonviral gene transduction method. Furthermore, the NBL-1-based gene transfer mediated the formation of more than 20-fold higher numbers of drug-resistant colonies. In contrast, RET-negative cells, which included HeLa, HT1080, Caco-2, and Colo205 cells, did not show any increased expression of an exogenous gene by NBL-1. These data suggest that the RET molecules enable selective gene transduction, and that NBL-1 may possibly be applied to gene therapy for neuroblastomas and Parkinson's disease.

Induction of apoptosis in human hematopoietic U937 cells by granulocyte-macrophage colony-stimulating factor: possible existence of caspase 3-like pathway.

Granulocyte-macrophage colony-stimulating factor (GM-CSF) induced apoptosis in human hematopoietic U937 cells by itself and in a synergistic manner with tumor necrosis factor (TNF). GM-CSF-induced apoptosis was not inhibited by caspase inhibitors YVAD-CMK, DEVD-CHO and z-VAD-FMK, under the condition that these inhibitors potently suppressed TNF-induced apoptosis. Both GM-CSF and TNF induced caspase 3-like activity in this cell line though the time course was distinct between two cytokines, and combined stimulation of cells with GM-CSF plus TNF induced additive or synergistic activation of caspase 3-like activity. Amount of immunoreactive cleaved forms of caspase 3 recognized by specific antibody was completely dissociated with its enzymatic activity when the cells were stimulated with GM-CSF, but not with TNF. These results indicate that GM-CSF induces apoptosis of U937 cells via unknown pathway, which seems to be mediated by caspase 3-like activity, yet not caspase 3 itself, resistant to the caspase inhibitors, and synergistically interacts with conventional caspase 3 pathway of TNF. Possible involvement of caspases 1 and 8 (-like activity) but not caspase 7 in this pathway was also suggested.

NH2-terminal pentapeptide of endothelial interleukin 8 is responsible for the induction of apoptosis in leukemic cells and has an antitumor effect in vivo.

We have reported that endothelial interleukin 8 (IL-8) induces apoptosis in leukemic cells in vitro and in vivo, and that interaction between endothelial cells and leukemic cells causes induction of apoptosis through the release of endothelial IL-8 (Y. Terui et al., Biochem. Biophys. Res. Commun., 243: 407-411, 1998; Y. Terui et al., Blood, 92: 2672-2680, 1998). Here, we examined whether a pentapeptide corresponding to the NH2-terminal region of endothelial IL-8 can induce apoptosis in leukemic cells. The NH2-terminal pentapeptide Ala-Val-Leu-Pro-Arg (AVLPR) was found to significantly induce apoptosis in the leukemic cell lines K562, HL-60, Jurkat, and Daudi, as compared with the COOH-terminal pentapeptide Arg-Glu-Ala-Asn-Ser (REANS). Moreover, the NH2-terminal pentapeptide AVLPR significantly inhibited growth of i.p. and s.c. tumor masses of K562 cells and induced apoptosis in these cells in vivo. The active site of endothelial IL-8 is the NH2-terminal pentapeptide AVLPR, and this may serve as a new therapy for hematological malignancies.

Beta(2)-microglobulin identified as an apoptosis-inducing factor and its characterization.

Major histocompatibility complex (MHC) molecules play an important role in antigen presentation for induction of tumor as well as cellular and humoral immunities. Recent studies using anti-MHC antibodies demonstrated that antibodies specific for HLA class I molecules induced cellular activation and a type of apoptosis that may be distinct from Fas-dependent or TNFR (tumor necrosis factor-alpha receptor)-dependent processes. We purified a previously untested apoptosis-inducing factor from HL-60 human leukemic cell-conditioned media to homogeneity and sequenced it. It was identified as beta(2)-microglobulin (beta(2)m), which has been previously known as thymotaxin and is a part of the HLA class I antigen complex. beta(2)m acts on both T-leukemic cells and myeloid leukemic cells to induce apoptosis, which then activates caspase 1 and 3. Cross-linking studies showed that biotinilated beta(2)m recognized an epitope distinct from those recognized by the anti-HLA class I antibody, as reported previously. We demonstrated that beta(2)m plays a previously unrecognized and important role in regulating the elimination of tumor cells, which occurs as a result of the action of beta(2)m as an apoptosis-inducing factor.

Long-term clinical and echocardiographic outcome in patients with mitral stenosis treated with percutaneous transvenous mitral commissurotomy.

Long-term follow-up after percutaneous transvenous mitral commissurotomy (PTMC) is limited. Ninety-four middle-aged (51+/-9 years) mitral stenosis patients who underwent successful PTMC were followed up with annual echocardiography for 6.1+/-1.4 years. PTMC success was defined as either mitral valve area (MVA) >1.5 cm2 or a MVA of more than twice the pre-procedural value, together with no worsening of mitral regurgitation >grade 2+. Mitral valve replacement (MVR), worsening of congestive heart failure (CHF), and thromboembolism were sought for survival analysis. Restenosis was defined as loss of more than 50% of the initial procedural MVA gain. Functional limit of daily activities was assessed through a questionnaire. The study population was divided into group 1 (post-procedural MVA >2.0 cm2), group 2 (MVA > 1.5 cm2 and < or = 2.0 cm2) and group 3 (MVA < or = 1.5 cm2). The 6-year survival with freedom from MVR, CHF, thromboembolism, and combined events (MVR+CHF) was 92%, 95%, 91%, and 88%, respectively. No group 1 patient experienced MVR or CHF. Restenosis was predominant in group 3. Deterioration of daily activities during follow-up was not observed in group 1; however, it was significant in group 2 (p<0.05) and group 3 (p<0.001). These results demonstrated that patients who attained a large MVA (>2.0cm2) immediately after PTMC maintained their procedural benefit with less clinical complication and with less limitation of daily activity.

Inhibition of Vpr-induced cell cycle abnormality by quercetin: a novel strategy for searching compounds targeting Vpr.

Vpr, an accessory gene product of HIV-1 which induces cell cycle abnormality leading to the increased HIV replication, is supposed to be a possible target for anti-AIDS drugs. We recently established a cell line (MIT-23) in which Vpr-induced cell cycle perturbation could be manipulated by a tetracycline promoter. Here, we screened anti-Vpr activity in 27 kinds of herb drugs using MIT-23 cells. One of the extracts prepared from Houttuyniae herba showed an inhibitory activity. Quercetin (QCT), a compound of this crude drug, efficiently inhibited Vpr function without affecting its expression. Furthermore, data suggested that Vpr-induced transcription from HIV-LTR was considerably abrogated by QCT. These data indicate that QCT, a flavonoid previously reported to inhibit HIV replication, also targets Vpr, implicating that MIT-23 cell provides a novel strategy for screening compounds possessing anti-Vpr activity which would be in turn utilized for clarifying the mechanism of Vpr function.

Multiple centrosome formation induced by the expression of Vpr gene of human immunodeficiency virus.

We previously established a cell line called MIT-23 in which expression of the Vpr gene of human immunodeficiency virus 1 (HIV-1) can be controlled by the addition of tetracycline. Vpr expression induces multiple nuclear formation and increased ploidy in MIT-23 cells. We herein report that multipolar mitotic spindles were formed upon induction of Vpr. Further analysis of centrosomes with anti-gamma-tubulin immunostaining revealed that a significant population of cells 1 week after expression of Vpr gene product had an increased number of centrosomes in the cells with abnormal nuclei. Taking into account that the centrosome plays an important role in genome integrity, the abnormal number of centrosomes in cells expressing Vpr may be directly related to aneuploidy or the formation of micronuclei in MIT-23 cells, suggesting that Vpr has an oncogenic role in HIV infected cells.

Micronuclei formation with chromosome breaks and gene amplification caused by Vpr, an accessory gene of human immunodeficiency virus.

Vpr, an accessory gene of human immunodeficiency virus, induces cell cycle abnormality by accumulating cells at the G2-M phase. We reported recently that Vpr caused both micronuclei formation and aneuploidy. Here, we show that Vpr also induced chromosome breaks and gene amplification. Expression of Vpr induced more than 10-fold increase of colonies resistant to N-(phosphonacetyl)-L-aspartate, an inhibitor of pyrimidine de novo synthesis. Fluorescence in situ hybridization analysis detected that 4 of 10 N-(phosphonacetyl)-L-aspartate resistant clones studied had intrachromosomal amplification of carbamyl-phosphate synthetase/aspartate transcarbamoylase/dihydroorotase gene. Another single clone had dicentrics. Data suggested that the Vpr-induced chromosome breaks leading to gene amplification, followed by bridge-breakage-fusion cycle, were one of the possible mechanisms of Vpr-induced genomic instability.

Plasma adrenomedullin and natriuretic peptides in patients with essential or malignant hypertension.

Adrenomedullin (AM), a potent vasodilator and natriuretic peptide, is found in human blood. To investigate the pathophysiological role of AM in essential and malignant hypertension (EHT and MHT), we measured the plasma concentrations of AM in patients with EHT of WHO stage I or II (n = 42) and in those with MHT (n = 9) by a specific radioimmunoassay, and compared these concentrations with those in normotensive controls (n = 46). The plasma concentrations of atrial and brain natriuretic peptides (ANP and BNP) in these subjects were also measured by immunoradiometric assays, and their relations to plasma AM were examined. The plasma AM level in the EHT patients (7.15+/-0.21 pmol/l, mean+/-SEM) was significantly (p < 0.01) higher than that in the normotensive controls (6.14+/-0.25 pmol/l), and a further elevation was observed in the MHT patients (14.1+/-3.8 pmol/l). Similar elevations of plasma ANP and BNP were seen in the two patient groups. The plasma AM level significantly (p < 0.01) correlated with not only the systolic (r = 0.44) and diastolic (r = 0.46) blood pressures, but also with the plasma levels of ANP (r = 0.43) and BNP (r = 0.43). The elevated plasma concentration of AM in the MHT patients decreased significantly (p < 0.05) after antihypertensive treatment, and the plasma ANP and BNP levels similarly declined. These results suggest that AM may participate, along with ANP and BNP, in mechanisms counteracting a further elevation of blood pressure in patients with EHT and MHT.

Micronuclei formation and aneuploidy induced by Vpr, an accessory gene of human immunodeficiency virus type 1.

Vpr, an accessory gene of HIV-1, induces cell cycle abnormality with accumulation at G2/M phase and increased ploidy. Since abnormality of mitotic checkpoint control provides a molecular basis of genomic instability, we studied the effects of Vpr on genetic integrity using a stable clone, named MIT-23, in which Vpr expression is controlled by the tetracycline-responsive promoter. Treatment of MIT-23 cells with doxycycline (DOX) induced Vpr expression with a giant multinuclear cell formation. Increased micronuclei (MIN) formation was also detected in these cells. Abolishment of Vpr expression by DOX removal induced numerous asynchronous cytokinesis in the multinuclear cells with leaving MIN in cytoplasm, suggesting that the transient Vpr expression could cause genetic unbalance. Consistent with this expectation, MIT-23 cells, originally pseudodiploid cells, became aneuploid after repeated expression of Vpr. Experiments using deletion mutants of Vpr revealed that the domain inducing MIN formation as well as multinucleation was located in the carboxy-terminal region of Vpr protein. These results suggest that Vpr induces genomic instability, implicating the possible role in the development of AIDS-related malignancies.

Activated endothelial cells induce apoptosis in leukemic cells by endothelial interleukin-8.

Tumor cells are eradicated by several systems, including Fas ligand-Fas and tumor necrosis factor (TNF)-tumor necrosis factor receptor (TNFR). In the previous study, we purified an apoptosis-inducing factor (AIF) to homogeneity from a medium conditioned by PDBu-treated HL-60 cells. N-terminal sequence analysis showed that AIF is identical to endothelial interleukin-8 (IL-8). A novel apoptosis system, in which endothelial cells participate via endothelial IL-8 release, is identified here. Human umbilical vein cells (VE cells) produce and secrete IL-8 by stimulation of IL-1alpha and TNF-alpha. Endothelial IL-8, which is secreted from VE cells by stimulation of IL-1alpha and TNF-alpha , induces apoptosis in myelogenous leukemia cell line K562 cells. Monocyte-derived IL-8 could not induce apoptosis in K562 cells. Moreover, interaction between VE cells and K562 cells induces the release of endothelial IL-8 from VE cells, and the attached K562 cells undergo apoptosis. Moreover, interactions between VE cell and other cell lines, such as HL-60, U937, Jurkat, and Daudi, induce the secretion of endothelial IL-8 and the induction of apoptosis in cell lines. Endothelial IL-8 significantly inhibits tumor growth of intraperitoneal and subcutaneous tumor mass of K562 cells and induces apoptosis in their cells in vivo. Endothelial IL-8 plays an important role in apoptosis involving endothelial cells, which may provide us with a new therapy for hematological malignancies.