Intermittent microwave irradiation facilitates antigen-antibody reaction in Western blot analysis.

We established a shortened protocol for western blot analysis using intermittent microwave irradiation. With this method, the procedure is completed within 1 h after applying the primary antibody, and thus greatly saves time. This procedure appears to be applicable to any antibody based on our experience of several years.

Mechanisms of asbestos-induced carcinogenesis.

Respiratory exposure to asbestos fibers has been associated with diffuse malignant mesothelioma (DMM) in humans. Despite advancements in the molecular analyses of human DMM and the development of animal models, the carcinogenic mechanisms of the disease remain unclear. There are basically three hypotheses regarding the pathogenesis of asbestos-induced DMM, which may be summarized as follows: (1) the "oxidative stress theory" is based on the fact that phagocytic cells that engulf asbestos fibers produce large amounts of free radicals due to their inability to digest the fibers, and epidemiological studies indicating that iron-containing asbestos fibers appear more carcinogenic; (2) the "chromosome tangling theory" postulates that asbestos fibers damage chromosomes when cells divide; and (3) the "theory of adsorption of many specific proteins as well as carcinogenic molecules" states that asbestos fibers in vivo concentrate proteins or chemicals including the components of cigarette smoke.

Abnormal DNA methyltransferase expression in mouse germline stem cells results in spermatogenic defects.

Although spermatogonial stem cells (SSCs) are committed to spermatogenesis, they may also convert to an embryonic stem cell-like pluripotent state at a low frequency. Because changes in DNA methylation patterns are associated with this conversion, we examined the effect of manipulating DNA methyltransferase (Dnmt) expression on the fate of cultured SSCs, germline stem (GS) cells. Dnmt1 knockdown induced apoptosis in GS cells, which was attenuated by the loss of Trp53.

Granulocyte colony-stimulating factor protects cardiac mitochondria in the early phase of cardiac injury.

Although granulocyte colony-stimulating factor (G-CSF) reportedly plays a cardioprotective role in several models of cardiac injury, clinical use of this drug in cardiac patients has been controversial. Here, we tested, in vivo and in vitro, the effect of G-CSF on cardiac mitochondria, which play a key role in determining cardiac cellular fate and function. Mild stimulation of C57/BL6 mice with doxorubicin (Dox) did not induce cardiac apoptosis or fibrosis but did induce damage to mitochondrial organization of the myocardium as observed through an electron microscope.

Genome-wide analysis identifies a tumor suppressor role for aminoacylase 1 in iron-induced rat renal cell carcinoma.

A growing number of studies indicate a link between oxidative stress and cancer. We previously developed a rat model of renal cell carcinoma (RCC) induced by ferric nitrilotriacetate (Fe-NTA). Here, we performed a genome-wide analysis to study characteristics of genomic alteration and identify putative genes involved in the development of Fe-NTA-induced RCCs.

Role of iron in carcinogenesis: cancer as a ferrotoxic disease.

Iron is abundant universally. During the evolutionary processes, humans have selected iron as a carrier of oxygen inside the body. However, iron works as a double-edged sword, and its excess is a risk for cancer, presumably via generation of reactive oxygen species.

Induction of autophagy in malignant rhabdoid tumor cells by the histone deacetylase inhibitor FK228 through AIF translocation.

Malignant rhabdoid tumors (MRT) exhibit a very poor prognosis because of their resistance to chemotherapeutic agents and new therapies are needed for the treatment of this cancer. Here, we show that the histone deacetylase (HDAC) inhibitor FK228 (depsipeptide) has an antitumor effect on MRT cells both in vitro and in vivo. FK228 is a unique cyclic peptide and is among the most potent inhibitors of both Class I and Class II HDACs.

Characteristics and modifying factors of asbestos-induced oxidative DNA damage.

Respiratory exposure to asbestos has been linked with mesothelioma in humans. However, its carcinogenic mechanism is still unclear. Here we studied the ability of chrysotile, crocidolite and amosite fibers to induce oxidative DNA damage and the modifying factors using four distinct approaches.

A high-throughput reporter gene assay to prove the ability of natural compounds to modulate glutathione peroxidase, superoxide dismutase and catalase gene promoters in V79 cells.

The aim of the study was to establish a 96-well microtiter plate-based reporter gene assay to test the influence of natural compounds on the promoter activities of rat catalase, human glutathione peroxidase and human superoxide dismutase expressed in V79 cells. Luciferase expression vectors with the promoter regions of the genes coding for the three above-mentioned enzymes were constructed and transfected into V79 cells. Thereafter the ability of sodium ascorbate, L-carnitine, catechin, epigallocatechin gallate, genistein, paraquat, quercetin, 12-O-tetradecanoylphorbol-13-acetate and Trolox to enhance the promoter activities was evaluated.

The Bcr-Abl kinase inhibitor INNO-406 induces autophagy and different modes of cell death execution in Bcr-Abl-positive leukemias.

Bcr-Abl tyrosine kinase (TK) inhibitors are promising therapeutic agents for Bcr-Abl-positive (Bcr-Abl(+)) leukemias. Although they are known to promote caspase-mediated apoptosis, it remains unclear whether caspase-independent cell death-inducing mechanisms are also triggered. Here we demonstrated that INNO-406, a second-generation Bcr-Abl TK inhibitor, induces programmed cell death (PCD) in chronic myelogenous leukemia (CML) cell lines through both caspase-mediated and caspase-independent pathways.

Protein N-acylation: H2O2-mediated covalent modification of protein by lipid peroxidation-derived saturated aldehydes.

Various lines of evidence indicate that the oxidative modification of protein and the subsequent accumulation of the degenerated proteins have been found in cells and tissues during aging, oxidative stress, and in a variety of pathological states. The critical agents that give rise to this protein degeneration may be represented by aldehydes. Although the covalent modification of proteins by aldehydes alone has been well-studied, the effect of reactive oxygen species, such as H2O2, upon aldehyde modification of the protein has received little attention.

Molecular mechanisms of oxidative stress-induced carcinogenesis: from epidemiology to oxygenomics.

Oxidative stress is associated with inflammation, radiation, reperfusion, and iron overload. Epidemiological observations have shown that oxidative stress is one of the major sources of carcinogenesis, the top-ranked cause of human mortality worldwide. In situations of oxidative stress, reactive oxygen and nitrogen species contribute to the alteration of genome information, presumably followed by selection of the adapted proliferating cells in a given environment.

Increased susceptibility of chronic ulcerative colitis-induced carcinoma development in DNA repair enzyme Ogg1 deficient mice.

Ogg1 DNA repair enzyme recognizes and excises oxidative stress-caused 8-hydroxyl-deoxyguanosine (8-OHdG) from GC base-pairs. Ogg1 knockout mice are phenotypically normal, but exhibit elevated levels of 8-OHdG in nuclear and mitochondrial DNA, as well as moderately elevated mutagenesis and spontaneous lung tumors and UV-induced skin tumors. To elucidate the mechanistic role of inflammation-caused oxidative stress in carcinogenesis, the development of chronic ulcerative colitis (UC)-induced carcinoma in Ogg1 knockout mice was studied using a dextran sulfate sodium (DSS)-induced UC model without the use of a carcinogen.

Pluripotency of a single spermatogonial stem cell in mice.

Although pluripotent stem cells were recently discovered in postnatal testis, attempts to analyze their developmental potential have led to conflicting claims that spermatogonial stem cells are pluripotent or that they lose spermatogenic potential after conversion into pluripotent stem cells. To examine this issue, we analyzed the developmental fate of a single spermatogonial stem cell that appeared during transfection experiments. After transfection of a neomycin-resistance gene into germline stem cells, we obtained an embryonic stem-like, multipotent germline stem cell line.

Contents of endometriotic cysts, especially the high concentration of free iron, are a possible cause of carcinogenesis in the cysts through the iron-induced persistent oxidative stress.

Purpose: Endometriotic cysts are known to transform into ovarian cancers, such as clear cell and endometrioid carcinomas. We hypothesized that an iron-rich environment produced by the repetition of hemorrhage in the endometriotic cysts during the reproductive period may play a crucial role in carcinogenesis in the cysts through the iron-induced persistent oxidative stress.

Experimental Design: Contents of human ovarian cysts, including 21 endometriotic cysts, 4 clear cell carcinomas, and 11 nonendometriotic cysts, were analyzed for the concentrations of free "catalytic" iron, lactose dehydrogenase, potential antioxidant, lipid peroxide, and 8-hydroxy-2'-deoxyguanosine (8-OHdG).

Chronic oxidative stress causes amplification and overexpression of ptprz1 protein tyrosine phosphatase to activate beta-catenin pathway.

Ferric nitrilotriacetate induces oxidative renal tubular damage via Fenton-reaction, which subsequently leads to renal cell carcinoma (RCC) in rodents. Here, we used gene expression microarray and array-based comparative genomic hybridization analyses to find target oncogenes in this model. At the common chromosomal region of amplification (4q22) in rat RCCs, we found ptprz1, a tyrosine phosphatase (also known as protein tyrosine phosphatase zeta or receptor tyrosine phosphatase beta) highly expressed in the RCCs.

Visualization and characterization of UVB-induced reactive oxygen species in a human skin equivalent model.

Reactive oxygen species (ROS) play important roles in the process of ultraviolet-induced skin damage or photoaging. Although many enzymatic and chemical methods have been developed for evaluating ROS, evaluation methods for ROS generation in living systems are quite limited. Here we propose a unique system to visualize UVB-induced ROS and investigate the biological impact of ROS.

Production of knockout mice by gene targeting in multipotent germline stem cells.

Spermatogonial stem cells can convert into embryonic stem (ES) cell-like multipotent germline stem (mGS) cells in vitro and produce germline chimeras by blastocyst microinjection. Although homologous recombination was previously demonstrated in mGS cells, spermatogenesis was not found in chimeras, suggesting that they are not competent for germline modification. Here we conducted detailed analysis of chimeric animals to determine whether mGS cells retain germline potential after genetic manipulation.

Association of microRNA-34a overexpression with proliferation is cell type-dependent.

Recently Welch et al. reported that microRNA (miRNA)-34a functions as a potential tumor suppressor in neuroblastoma cells (Oncogene 26: 5017-22, 2007). Here, we conversely show that miRNA-34a supports cell proliferation in rat oxidative stress-induced renal carcinogenesis and is overexpressed in various types of human cancers.

FasL expression in hepatic antigen-presenting cells and phagocytosis of apoptotic T cells by FasL+ Kupffer cells are indicators of rejection activity in human liver allografts.

Fas-Fas ligand (FasL) interaction and apoptosis are important in the mechanism of allograft rejection. However, the interaction between donor and recipient cells, specifically focusing on antigen-presenting cells (APCs), under various conditions is poorly understood in human liver allografts. FasL expression on APCs, its association with apoptosis, and the origin of apoptotic lymphocytes in human liver allografts were assessed by immunohistochemistry and in situ hybridization.

Overexpression of CYP3A aggravates endotoxin-induced liver injury in hypophysectomized female rats.

Aim: CYP3A2 is a male-specific isoform of cytochrome P450 enzyme which is expressed abundantly in male rats but not in intact female rats. Having previously reported that hepatic CYP3A2 promotes lipopolysaccharide (LPS)-induced liver injury in male rats, we further examined the impact of CYP3A on LPS-induced liver injury by comparing intact and hypophysectomized female rats. In hypophysectomized female rats, phenobarbital (PB), a cytochrome P450 inducer, markedly increased the hepatic content and activity of CYP3A1/2, but did not do so in intact rats.

Oxidative stress is related to the formation of Antoni B patterns and eosinophilic hyaline droplets in schwannomas.

Schwannomas, particularly of vestibular origin, often accompany degenerative hypocellular areas known as Antoni B patterns; however, the detailed mechanism is uncertain. Eosinophilic hyaline droplets (EHD), the substantial nature of which are autophagic vacuoles, preferentially appear in acoustic schwannomas and distribute around areas of Antoni B. We investigated their common background using schwannomas with (15 cases) or without (10 cases) EHD, and demonstrated that EHD showed selective immunoreactivity with an anti-nitrotyrosine antibody, suggesting the overproduction of nitric oxide in this condition.

Pathological investigation of oxidative stress in the post-genomic era.

Aerobes, including humans, are consistently exposed to oxidative stress by consuming oxygen. The biological significance of oxidative stress via reactive oxygen and nitrogen species consists of two stages: reversible redox regulation and irreversible oxidative molecular damage, which are sometimes intermingled. During the past decade, many signaling cascades associated with oxidative stress have been discovered.

ARMET is a soluble ER protein induced by the unfolded protein response via ERSE-II element.

Arginine rich, mutated in early stage of tumors (ARMET) was first identified as a human gene highly mutated in a variety of cancers. However, little is known about the characteristics of the ARMET protein and its expression. We identified ARMET as a gene upregulated by endoplasmic reticulum (ER) stress.

Overexpression of a transcription factor LYL1 induces T- and B-cell lymphoma in mice.

LYL1, a member of the class II basic helix-loop-helix transcription factors, is aberrantly expressed in a fraction of human T-cell acute lymphoblastic leukemia. Here, we generated transgenic mice ubiquitously overexpressing LYL1 using a construct expressing full-length cDNA driven by a human elongation factor 1alpha promoter. Four independent lines exhibiting high LYL1 expression were established.