Maki Koh

Induction of Apoptosis by γ-Tocotrienol in Human Cancer Cell Lines and Leukemic Blasts From Patients: Dependency on Bid, Cytochrome c, and Caspase Pathway

Tocotrienols (Toc3) have been suggested to possess anticancer effects besides antioxidant and antiinflammatory effects. Previous studies have demonstrated that Toc3 induce apoptosis in epithelial carcinoma. However, the effects of Toc3 on malignant hematopoietic cells have not yet been thoroughly investigated. We investigated Toc3-induced apoptosis in human hematological cancer cell lines. α-, δ-, and γ-Toc3 induced concentration-dependent apoptosis, and γ-Toc3 demonstrated more effective induction than the other Toc3 derivatives in HL-60 cells. γ-Toc3 may have induced apoptosis by activation of the caspase cascade, cytochrome c (Cyt.c) release, Bid cleavage, and mitochondorial membrane depolarization in HL-60, NB-4, Raji, and SY-5Y cells. Furthermore, 10–30 μM γ-Toc3 showed cytotoxicity for leukemic cells from various patients regardless of lymphoblastic, myeloblastic, or relapsed leukemia, but the cytotoxic effect was weak in normal mononuclear cells, interestingly. γ-Toc3 may have a role in cancer prevention and potential for treating hematological malignancies.

Plasma All-Trans Retinoic Acid Level in Neonates of Mothers with Acute Promyelocytic Leukemia

We have encountered 3 cases of APL in pregnancy as shown in table 1 . All 3 mothers were diagnosed as having APL in the third trimester. They received standard oral induction therapy with ATRA (45 mg/m 2 divided into 2 doses) for 2–4 weeks. Chemotherapy was performed after cesarean section. All of them achieved complete remission after this additional chemotherapy. None of the mothers suffered any toxicity during ATRA therapy. All the neonates were delivered safely, but had the complications shown in table 1 . All of them required intubation for respiratory distress syndrome (RDS). Their complications improved with appropriate treatment. Case 2 was reported previously because this neonate had premature atrial contraction [5] . Laboratory data were within the normal range and none of the neonates had dermatitis, dry skin, or cheilitis, which are known toxicities of ATRA. We measured the plasma ATRA level in umbilical cord blood, as well as in the mothers and neonates ( fi g. 1 A). The method of measuring ATRA levels has been described previously [8] . ATRA was detected in the maternal plasma of case 2, and in the maternal and neonatal plasma of case 3. Transfer of ATRA to the fetus occurred as shown in fi gure 1 B. 9cis RA and 13cis RA, which are Alltrans retinoic acid (ATRA) therapy for acute promyelocytic leukemia (APL) achieves a high complete remission rate with mild side effects during induction therapy. APL is characterized by the chromosomal translocation (15; 17), which results in fusion of the PML gene and the retinoic acid receptor (RAR) gene. Recently, this translocation has been related to oncogenesis in APL, and identifi cation of the molecular mechanism of oncogenesis is underway. The administration of chemotherapy during the fi rst trimester is associated with a high rate of fetal malformation [1] . However, it has been reported that pregnant women with APL can be treated by ATRA and control of disseminated intravascular coagulation during the second and third trimesters allowing safe delivery of the fetus with no serious complications [2–6] . Although vitamin A and its derivatives are known to be teratogenic in early pregnancy, little is known about its effects in late pregnancy [7] . In this study, we measured plasma ATRA levels in the umbilical cord blood of neonates born to mothers treated with ATRA during pregnancy. These neonates were followed up after delivery. Received: August 26, 2004 Accepted after revision: February 8, 2005

The α-tocopherol status and expression of α-tocopherol-related proteins in methionine-choline deficient rats treated with vitamin E

Non-alcoholic fatty liver disease is the most common liver disorder in developed countries, and its incidence is increasing in all population groups. As an antioxidant, vitamin E is effective in the treatment of non-alcoholic fatty liver disease, although the mechanism is still unclear. Methionine-choline deficient Wistar rats (n = 5) used as an experimental model of non-alcoholic fatty liver disease were fed a vitamin E-enriched diet (500 mg/kg) for 4 weeks. The effects were assessed by measuring lipid peroxidation, α-tocopherol levels, and the expression of α-tocopherol-related proteins in the liver. In vitamin E-treated methionine-choline deficient rats, lipid peroxidation was reduced, but liver histopathological changes were not improved. Hepatic α-tocopherol levels in these rats were significantly elevated compared to normal rats treated with vitamin E. Expression of liver α-tocopherol transfer protein in vitamin E-treated methionine-choline deficient rats was significantly repressed compared to methionine-choline deficient rats. The expression of liver cytochrome P450 4F2 and ATP-binding cassette transporter protein 1, involved in metabolism and transport of α-tocopherol, respectively, was significantly repressed in vitamin E-treated methionine-choline deficient rats. In methionine-choline deficient rats, vitamin E treatment altered the hepatic α-tocopherol-related protein expression, which may affect α-tocopherol status in the liver, leading to reduced lipid peroxidation.

Liver X receptor up-regulates α-tocopherol transfer protein expression and α-tocopherol status.

Fat-soluble vitamin E (α-tocopherol) has antioxidant activity. α-Tocopherol transfer protein (α-TTP), a hepatic cytosolic protein, selectively binds α-tocopherol and has an important role regulating circulatory α-tocopherol levels. However, only a few studies have shown the transcriptional regulation of the α-TTP gene. Here, we demonstrate that liver X receptor (LXR) regulates α-TTP expression through direct interaction with the α-TTP gene promoter, and it modulates circulating α-tocopherol levels. LXR belongs to the nuclear receptor superfamily, acts as a ligand-dependent transcription factor for oxysterols and plays an important role in cholesterol metabolism and lipogenesis. We identified an LXR response element (LXRE; DR4, a direct repeat with four-nucleotides spacing) of the human α-TTP gene promoter by using luciferase and electrophoretic mobility shift assays. Mutations in this element abolished activation of this promoter. Moreover, treatment of vitamin E-deficient rats with T0901317, a synthetic LXR ligand, increased α-TTP expression in the liver and cerebrum and increased the plasma α-tocopherol levels. These results indicate that the LXR signaling pathway modulates α-TTP gene expression and plasma α-tocopherol levels. Our observations imply that the LXR signaling pathway might be a useful target for antioxidant properties by controlling the vitamin E status.

Case treated with triple therapy of lamivudine, interferon-β and prednisolone for acute exacerbation of chronic hepatitis B during pregnancy.

We herein report a case of a pregnant Chinese woman who suffered an acute exacerbation of hepatitis B. The patients liver enzymes became elevated toward the end of the first trimester. She was treated with lamivudine, interferon (IFN)‐β and steroids early in the second trimester. After this treatment regimen was initiated, aminotransferase levels rapidly normalized within 4 weeks. IFN‐β and steroids were administrated for 2 weeks in the second trimester, while the administration of lamivudine continued until delivery. The spontaneous delivery of a female baby weighing 2984 g occurred at 37 weeks of gestation. A neonatal examination revealed no congenital anomalies, and fetal growth was found to be within normal reference ranges. The infant received simultaneous active and passive hepatitis B virus immunization within 12 h of delivery and completed the hepatitis B vaccine schedule at 2, 3 and 5 months of age. The infant was successfully prevented from contracting hepatitis B virus. This case suggests that combination therapy with lamivudine, IFN‐β and steroids may be safely used during the second trimester to treat acute exacerbations of hepatitis B.

Dehydroepiandrosterone alters vitamin E status and prevents lipid peroxidation in vitamin E-deficient rats

In humans, dehydroepiandrosterone and its sulfate ester metabolite DHEA-S are secreted predominantly from the adrenal cortex, and dehydroepiandrosterone is converted to steroid hormones, including androgens and estrogens, and neurosteroid. Dehydroepiandrosterone exerts protective effects against several pathological conditions. Although there are reports on the association between dehydroepiandrosterone and vitamins, the exact relationship between dehydroepiandrosterone and vitamin E remains to be determined. Therefore, we attempted to elucidate the effect of dehydroepiandrosterone on vitamin E status and the expression of various vitamin E-related proteins, including binding proteins, transporters, and cytochrome P450, in vitamin E-deficient rats. Plasma α-tocopherol levels in vitamin E-deficient rats increased in response to dehydroepiandrosterone administration. The expression of hepatic α-tocopherol transfer protein was repressed in vitamin E-deficient rats compared to that in control rats; however, dehydroepiandrosterone administration significantly upregulated this expression. Hepatic expression of CYP4F2, an α-tocopherol metabolizing enzyme, in vitamin E-deficient rats was decreased by dehydroepiandrosterone administration, whereas hepatic expression of ATP-binding cassette transporter A1, an α-tocopherol transporter, was not altered following dehydroepiandrosterone administration. Dehydroepiandrosterone repressed lipid peroxidation in the liver of vitamin E-deficient rats. Therefore, adequate dehydroepiandrosterone supplementation may improve lipid peroxidation under several pathological conditions, and dehydroepiandrosterone may modulate α-tocopherol levels through altered expression of vitamin E-related proteins.

Three brothers of X-linked agammaglobulinemia: the relation between phenotype and neutropenia

X-linked agammaglobulinemia (XLA, i.e. Bruton’s agammaglobulinemia [1]) is an X chromosomal recessive primary immunodeficiency syndrome, which is caused by insufficiency of antibody production. In 1993, BTK (Bruton’s tyrosine kinase) gene, the critical gene of XLA, was discovered in Xq22 by Tsukada et al. [2] and Vetrie et al. [3]. We report a family case with XLA, and describe the difference of clinical outcome between the proband and his brothers.

Expression of retinoic acid receptor-target genes during retinoic acid therapy for acute promyelocytic leukemia.

Expression of retinoic acid receptor–target genes during retinoic acid therapy for acute promyelocytic leukemia

α-Tocopherol Status and Altered Expression of α-Tocopherol-Related Proteins in Streptozotocin-Induced Type 1 Diabetes in Rat Models

Vitamin E plays a critical role as an antioxidant in several pathological conditions, including diabetes, cancer, cardiovascular diseases, and neurodegenerative disorders. Diabetes is a metabolic disorder of glucose due to the lack of adequate insulin production (type 1) or peripheral insulin resistance (type 2). Oxidative stress plays a major role in the pathogenesis of diabetes and its complications. The purpose of the present study was to determine α-tocopherol status and the expression of α-tocopherol-related proteins, including binding proteins and metabolizing enzymes, under streptozotocin (STZ)-induced type 1 diabetes in rat models. In STZ rats, plasma α-tocopherol levels decreased compared to the control rats, whereas hepatic α-tocopherol levels in the STZ rats were significantly increased. CuZn-superoxide dismutase (SOD) gene expression in the liver of STZ rats was markedly decreased, whereas Mn-SOD gene expression remained unaltered. Accelerated lipid peroxidation in the liver of STZ rats was observed and the hepatic expression of α-tocopherol transfer protein (α-TTP) in STZ rats decreased compared to that in the controls. The hepatic expression of cytochrome P450 4F2 (CYP4F2) and CYP3A2 genes in STZ rats also decreased. The reduced expression of hepatic α-TTP and CYP4F2 genes probably leads to decreased plasma α-tocopherol levels and elevated α-tocopherol levels in the liver of STZ rats. The altered expression of hepatic α-tocopherol-related proteins might regulate α-tocopherol status in type 1 diabetes. Determining the mechanism of modulating α-tocopherol status may be helpful in promoting antioxidant therapy in diabetes.

Altered Expression of Retinol Metabolism-Related Genes in an ANIT-Induced Cholestasis Rat Model

Cholestasis is defined as a reduction of bile secretion caused by a dysfunction of bile formation. Insufficient bile secretion into the intestine undermines the formation of micelles, which may result in the reduced absorption of lipids and fat-soluble vitamins. Here, we investigated the retinol homeostasis and the alterations of retinol metabolism-related genes, including β-carotene 15,15′ monooxygenase (BCMO), lecithin:retinol acyltransferase (LRAT), aldehyde dehydrogenase (ALDH), cytochrome P450 26A1 (CYP26A1), and retinoic acid receptors (RAR) β, in a α-naphthyl isothiocyanate (ANIT)-induced cholestasis rat model. Moreover, we examined the expression of the farnesoid X receptor (FXR) target genes. Our results showed that plasma retinol levels were decreased in ANIT rats compared to control rats. On the contrary, hepatic retinol levels were not different between the two groups. The expression of FXR target genes in the liver and intestine of cholestasis model rats was repressed. The BCMO expression was decreased in the liver and increased in the intestine of ANIT rats compared to control rats. Finally, the hepatic expression of LRAT, RARβ, and ALDH1A1 in cholestatic rats was decreased compared to the control rats, while the CYP26A1 expression of the liver was not altered. The increased expression of intestinal BCMO in cholestasis model rats might compensate for decreased circulatory retinol levels. The BCMO expression might be regulated in a tissue-specific manner to maintain the homeostasis of retinol.