β-1,4-Galactosyltransferase (β-1,4-GalT) V - whose human and mouse genes were cloned by us - has been suggested to be involved in the biosyntheses of N-glycans, O-glycans, and lactosylceramide by in vitro studies. Our recent study showed that β-1,4-GalT V-knockout mice are embryonic lethal, suggesting the importance of the glycans synthesized by β-1,4-GalT V for embryonic development. A subsequent study showed that murine β-1,4-GalT V is involved in the biosynthesis of lactosylceramide. It is well known that the glycosylation of cell surface glycoproteins and glycolipids changes dramatically upon the malignant transformation of cells. We found that among six β-1,4-GalTs the gene expression of only β-1,4-GalT V increases upon malignant transformation. The expression of the β-1,4-GalT V gene has been shown to be regulated by transcription factors Sp1 and Ets-1 in cancer cells. Both transcription factors regulate the gene expression levels of not only glycosyltransferases, but also key molecules involved in tumor growth, invasion and metastasis. Therefore, the abnormal glycosylation and malignant phenotypes of cancer cells are considered to be suppressed by regulating the expression levels of the transcription factor genes. This review gives a summary account of the gene discovery, in vivo function, and transcriptional mechanism of β-1,4-GalT V. Also, a perspective on applications of the manipulation of transcription factor genes to cancer therapy will be discussed.
Human bronchial mucins, such as MUC5AC, have traditionally been defined as a family of high-molecular weight glycoproteins. Changes in the contents of sugar chains on MUC5AC are among the fundamental features in inflammatory respiratory disease. The changes have been shown to lead to unfavorable alterations in the viscosity of mucus, resulting in impairment of mucociliary transport, vulnerability to viral/bacterial infection as sugar chains play an important role in adhesion of some viruses and bacteria to the epithelium, and finally inflammatory cell infiltration in the airway. Recently, we found that expression of some glycosyltransferases associated with the contents and structure of sugar chains is regulated by phosphatidylinositol-phospholipase (PI-PL) C signaling in cells. L-Carbocisteine, a mucoregulatory drug, normalized or balanced fucosylated and sialylated sugar chains, such as sialyl Lewis x through inhibition of PI-PL C signaling. We prepared MUC5AC fusion protein with tandem repeats associated with MUC5AC, and confirmed that L-carbocisteine inhibited the increases in viscosity associated with sialyl Lewis x expression levels. In addition, the clinical study (2008) noted that L-carbocisteine reduced the frequency of common colds and exacerbation of symptoms in patients with COPD. These favorable effects in patients may be due to normalization of sugar chain contents on mucins. We suggest that the inhibitory effect on infection of airway epithelial cells by rhinoviruses, respiratory syncytial virus, and influenza viruses by treatment with L-carbocisteine may also be based on the regulation of sugar chain contents or structures on mucins.
Sialyl Lewis X (sLeX) antigen, Neu5Acα2,3Galβ1,4(Fucα1,3)GlcNAc-R, is expressed on the glycoproteins in sera or the surface of the cells and the expression of sLeX is enhanced in various conditions such as the inflammation and cancer. SLeX in the serum is utilized as a tumor marker. To clarify the roles of sLeX on secreted glycoproteins in vivo, we investigate the regulation of natural killer (NK) cell-dependent cytotoxicity through sLeX. NK cells express many receptors to kill the target cells such as cancerous cells and non-self, and their protein ligands have been elucidated. Of the killer lectin-like receptors (KLRs) on NK cells, several have been reported to recognize glycans. Using recombinant extracellular domains of KLRs (rKLRs: rNKG2A, C, D and rCD94), we evaluated their glycan ligand specificity and binding affinities using EIA methods. We clarified that all of these rKLRs can bind to high sLeX-expressing glycoprotein and heparin, heparan sulfate and highly sulfated polysaccharides and that glycan binding sites on NKG2D are mostly overlapped with those of protein ligands. In this review, we show the recent findings concerning the glycan ligands of these KLRs.
As a new strategy for drug discovery and development, we propose here the establishment of drug re-profiling strategy. In this strategy, the actions of existing medicines, whose safety and pharmacokinetic effects in humans have been confirmed already, are examined comprehensively at the molecular level and the results are used for the development of new medicines. For example, identification of the mechanisms underlying the side effects of medicines enables us to develop safer drugs. The results can also be used for developing existing drugs for use as medicines in treatment of other diseases. Promoting this research strategy could provide breakthroughs in drug discovery and development by pharmaceutical companies.
Bone formation and maintenance are sophisticatedly orchestrated through a well-organized and highly regulated mechanism by two distinct cell types; bone-forming osteoblast and bone-resorbing osteoclast. It has been previously established that the adipocyte-derived hormone leptin regulates bone metabolism through the central nervous system and the sympathetic nervous system. We recently identified the osteoblast as the principal cell type in which the sympathetic tone could signal to regulate bone mass by generating and analyzing the cell specific adrenergic receptor deletion mice. The fact that adipocyte-derived hormone regulates bone metabolism implies that the skeleton might exert a feedback control of glucose metabolism. We then revealed that the skeleton acts as an endocrine regulator of energy metabolism through the osteoblast-specific secreted molecule osteocalcin that activates insulin secretion by pancreatic β-cells, insulin sensitivity in fat, liver, and muscle. Moreover, we have recently reported that the sympathetic tone into osteoblast is a pivotal mediator of leptin regulation of insulin secretion by regulating osteocalcin bioactivity. This unexpected functional cross talk between fat, nervous systems, and skeleton illustrates the importance of the skeleton for the regulation of major physiological functions such as glucose homeostasis in vertebrates.
This paper reports a specific and sensitive enzyme-linked immunosorbent assay (ELISA) for pharmacokinetic studies of vindesine (VDS). Anti-VDS antibody was obtained by immunizing rabbits with VDS conjugated with bovine serum albumin using N-[β-(4-diazophenyl) ethyl] maleimide as a heterobifunctional coupling agent. An enzyme marker was similarly prepared by coupling VDS with horseradish peroxidase using N-(4-diazophenyl) maleimide. The detection limit of VDS by ELISA was approximately 24 pg/mL with 50-mL samples. This assay was specific for VDS and showed very slight cross-reactivity with other vinca alkaloids, vincristine (0.18%) and vinblastine (0.11%). The values for the VDS concentrations detected using this assay were comparable with those detected using HPLC. There was a good correlation between the values determined by the two methods. Moreover, ELISA was about 50-fold more sensitive in detecting VDS at lower concentrations. The sensitivity and specificity of ELISA should provide a useful tool for pharmacokinetic studies of VDS.
We analyzed the target enzymes of drugs containing new active ingredients (NAIs) focusing on the characteristics of the reaction of the enzymes, and attempted to prepare a comprehensive overview of the changes in the approval of the drugs over a 3 decade period from 1980 to 2009 in Japan. Fifty-eight enzyme therapeutic targets of 235 NAIs were found to be primarily distributed to EC1, EC2 and EC3 classes, and the enzymes were unevenly distributed to 21 of 64 sub-classes and 34 of 264 sub-subclasses, respectively, classified by the enzyme nomenclature of the International Union of Biochemistry and Molecular Biology (IUBMB). Though the number of NAIs approved that targeted EC1 class enzymes decreased over the time frame studied, the number of NAIs which targeted EC2 class enzymes increased over the same time. There was no clear change in the number of NAIs which targeted other classes of enzymes. More than 80% of NAIs targeted one enzyme as a primary target, and less than 20% of NAIs targeted more than two enzymes as secondary targets. NAIs which primarily targeted EC2 and EC3 class enzymes had more secondary target enzymes than other classes. The results of this study revealed the characteristics of the reactions of the target enzymes of NAIs and the changes in NAI approvals in Japan during the three decades studied, and provided information regarding possible future trends of NAIs.
This study examined the impact of pharmaceutical inquiries regarding prescriptions on drug costs by surveying the actual condition of inquiries at 13 pharmacies. The study also investigated the significance of inquiries from a medical economics perspective by calculating the medical cost savings realized by preventing adverse drug reactions (ADRs). As a result, the total change in drug costs for the 13 pharmacies after pharmaceutical inquiries represented an increase of ¥9,018/month. However, upon recalculating the cost of drugs by assuming that those with an “Incomplete entry in the prescription (compared with previous prescription, etc.)” should in fact have been prescribed, and excluding them, the total drug costs for the 13 pharmacies is decreased to ¥154,743/month, translating to a cost-savings of ¥7.2/prescription. The study then undertook a comprehensive assessment based on the Diagnosis Procedure Combination (DPC) system to determine the total medical cost-savings for 5 patients in whom ADRs could have occurred if the prescriptions had not been modified as a result of pharmaceutical inquiries. The obtained figure of ¥1,188,830 suggests that pharmaceutical inquiries contribute to reduced medical costs. The findings of this study indicate that pharmaceutical inquiries regarding prescriptions by staff pharmacists not only ensure the proper delivery of drug therapy to patients, but are also effective from a medical economics perspective.
In accordance with Article 25-2 of the Pharmacists Act, pharmacists provide patients with information about the initial symptoms of adverse drug reactions for detecting and preventing those reactions. Thus far, however, there have been no reports quantitatively evaluating the usefulness of such information. We present a theory of information evaluation using posterior probability (PP), positive likelihood ratio (LR(+)) and incidence of nonspecific initial symptoms (NIS)—a measure of general symptoms without anything come to mind. First, we calculated using the data from the clinical trials. For liver damage caused by loxoprofen sodium hydrate, the LR(+) was as high as 27.9 in the presence of rash, but the PP was 0.002067, which means there were only 2 liver damage cases among 1000 rash cases. Calculated in the same way for voriconazole, the LR(+) was 5 and the PP was 0.2 (1 liver damage case among 5 rash cases). This suggests that information about rash as an initial symptom of liver damage is useful for patients taking voriconazole. However, the PP was greatly reduced when it was calculated by considering NIS. Since patients cannot distinguish initial symptom of side effect from mere change in body condition, the calculation considering NIS is realistic. Therefore, it is necessary to study in order to raise the value of the information service of the pharmacist. Our study demonstrates how PP and NIS, our new effective measure, allow a quantitative evaluation of the usefulness of information about initial symptoms.
The model core curriculum for pharmaceutical education specifies the specific behavioral objectives (SBOs) concerning adverse drug reactions, which aims to train pharmacy students to manage adverse drug reactions. Fukuoka University Hospital has developed a problem-based learning (PBL) program concerning adverse drug reactions as long-term practical training to collect adverse event information, identify adverse effects, and acquire management skills. Students' level of satisfaction with the program was high (approximately 90%), and the mean self-evaluation score for the SBOs concerning adverse reaction was 4.4 (5-grade scale), showing a high level of understanding. In addition, students' will of participation to the adverse drug reaction-reporting system was significantly improved after the PBL program, showing the usefulness of this program (p=0.02). However, the results of the PBL program revealed students' insufficient knowledge of adverse reactions and lack of reviewing skills, suggesting the need to improve the education system whereby students can learn adverse drug reactions in clinical settings.
The most effective drugs based on the type of cancer are chosen for chemotherapy. Tumor cells can be targeted at the DNA, RNA or protein level, and most of the classical anticancer drugs interact with tumor DNA in a time-dependent manner or a concentration-dependent manner. However, it has been unclear to date whether a combination therapy is carried out by using exact classification. Thus it is necessary to reclassify a great number of anticancer drugs. We propose a new classification system based on pharmacological effects of anticancer drugs. Classification of four anticancer drugs (cisplatin, carboplatin, paclitaxel and gemcitabine) was performed by the 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. The four anticancer drugs were grouped by IC50 values (inhibitory concentration, 50%) in a time-dependent manner and a concentration-dependent manner. The present approach may be combined to enhance the chemosensitivity, improve the dose of cytotoxic drugs and evaluate the effects of novel anticancer drugs.