Inactivation of the transforming growth factor  (TGF)-signaling pathway and gene silencing through hypermethylation of promoter CpG islands are two frequent alterations in human and experimental cancers. Here we report that nonneoplastic TGF1؊/؊ keratinocyte cell lines exhibit increased sensitivity to cell killing by alkylating agents, and this is due to lack of expression of the DNA repair enzyme O 6 -methylguanine DNA methyltransferase (MGMT). In TGF1؊/؊ but not TGF1؉/؊ cell lines, the CpG dinucleotides in the MGMT promoter are hypermethylated, as measured by restriction enzyme analysis and methylation specific polymerase chain reaction. In one unstable TGF1؉/؊ cell line, loss of the wild type TGF1 allele correlates with the appearance of methylation in the MGMT promoter. Bisulfite sequencing shows that in the KO3 TGF1؊/؊ cell line nearly all of the 28 CpG sites in the MGMT promoter 475 base pairs upstream of the start site of transcription are methylated, whereas most are unmethylated in the H1 TGF1؉/؊ line. Treatment of the TGF1؊/؊ cell lines with 5-azacytidine causes reexpression of MGMT mRNA and demethylation of CpG islands in the promoter. Analysis of the time course of methylation using methylation-specific polymerase chain reaction shows a lack of methylation in primary TGF1؊/؊ keratinocytes and increasing methylation with passage number of immortalized clones. Subcloning of early passage clones reveals a remarkable heterogeneity and instability of the methylation state in the TGF1؊/؊ keratinocytes. Thus, the TGF1؊/؊ genotype does not directly regulate MGMT methylation but predisposes cells to immortalization-associated MGMT hypermethylation.Inactivation of tumor suppressor genes is a common feature of cancer development in humans and animal models. There is increasing evidence that methylation of normally unmethylated CpG islands in gene promoters is an important epigenetic mechanism for transcriptional inactivation of tumor suppressor and DNA repair genes (1-3). One DNA repair gene that is frequently hypermethylated in tumors is methylguanine methyltransferase (MGMT) 1 (4, 5). MGMT removes alkyl adducts from O 6 -guanine residues by transferring the alkyl group to an active cysteine residue within its sequence in a reaction that inactivates further enzymatic activity (6). Since O 6 -alkylated guanine can mispair with thymine during replication to cause transversions as well as cross-link with cytosines on the opposite DNA strand (6), cells that are deficient in MGMT activity may be more susceptible to mutation and, hence, cancer development or progression. Supporting this role in cancer development, transgenic animals overexpressing MGMT are resistant to tumor formation induced by alkylating agents (7), whereas MGMT null animals exhibit an increased frequency of methylnitrosourea-induced tumors (8).TGF1 is a member of a large family of multifunctional secreted polypeptides that are potent growth inhibitors of epithelial cells (9). In human cancers and animal models of multistage carcinog...
Abstract-An experimental model of crescentic type nephritis was established by im munizing rats that had been given at i.v. nephritogenic dose (0.4 ml/animal) of rabbit anti-rat glomerular basement membrane (GBM) serum [anti-GBM serum] with 5 mg of rabbit r-globulin in Freund's complete adjuvant, and the process of nephritis was in vestigated by means of biochemical, histopathological and immunopathological analyses. Rats treated with anti-GBM serum and then with rabbit r-globulin (group II) showed significantly high levels or a tendency for high levels of urinary protein content, N-acetyl (3-glucosaminidase activity and plasmin-like activity from the 20th day to the 40th day observations after the induction of nephritis, when compared to rats given anti-GBM serum alone (group I). On the 40th day, plasma urea nitrogen, cholesterol and fibrinogen Currently, glucocorticoids, nonsteroidal anti -inflammatory agents, immunosuppres sants, anticoagulants and fibrinolytic agents are widely used for therapy of glomerulo nephritis. Human glomerulonephritis is clas sified into various types on the basis of clinical and histopathological findings. Masugi nephritis or its modification induced in rats or rabbits by an injection of anti-kidney serum (1, 2) or anti-glomerular basement membrane (anti-GBM) serum (3) has been chiefly employed as an experimental model for evaluating the antinephritic effect of drugs. It has been generally believed that the immunological mode of development of the anti-GBM nephritis in rats consists of the following two phases: Immediately after the injection of rabbit anti-rat GBM serum, the primary phase (heterologous phase) is caused by a reaction between anti-rat GBM antibody and host's GBM. Consecutively, 7 to 10 days later, the secondary phase (autologous phase) is induced by a reaction between rat antibody against rabbit r
Japan Pharmacogenomics Data Science Consortium (JPDSC) has assembled a database for conducting pharmacogenomics (PGx) studies in Japanese subjects. The database contains the genotypes of 2.5 million single-nucleotide polymorphisms (SNPs) and 5 human leukocyte antigen loci from 2994 Japanese healthy volunteers, as well as 121 kinds of clinical information, including self-reports, physiological data, hematological data and biochemical data. In this article, the reliability of our data was evaluated by principal component analysis (PCA) and association analysis for hematological and biochemical traits by using genome-wide SNP data. PCA of the SNPs showed that all the samples were collected from the Japanese population and that the samples were separated into two major clusters by birthplace, Okinawa and other than Okinawa, as had been previously reported. Among 87 SNPs that have been reported to be associated with 18 hematological and biochemical traits in genome-wide association studies (GWAS), the associations of 56 SNPs were replicated using our data base. Statistical power simulations showed that the sample size of the JPDSC control database is large enough to detect genetic markers having a relatively strong association even when the case sample size is small. The JPDSC database will be useful as control data for conducting PGx studies to explore genetic markers to improve the safety and efficacy of drugs either during clinical development or in post-marketing.
In Japan, drug therapy for schizophrenia is characterized by high-dose antipsychotic polypharmacy, which is an uncommon approach internationally. In this study, we reduced the number of antipsychotic agents in 5 patients using the Safety Correction of High-dose Antipsychotic Polypharmacy (SCAP) method and conducted a survey regarding treatment satisfaction. The switch from polypharmacy to monotherapy was achieved in all patients. There was no deterioration in psychiatric symptoms, and adverse reactions were reduced. Three of the subjects were satisfied with the decrease in the number of antipsychotic agents and dose-reduction. These results suggest that the SCAP method is a safe and useful method that can be applied in a clinical setting.
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