Single nucleotide polymorphisms of estrogen receptor alpha in human renal cell carcinoma

Estrogens and their receptors (ERs) have been shown to play a role in various cancers. We hypothesize that polymorphisms and genotypic changes of the ERalpha gene are involved in renal cell carcinoma. To test this hypothesis, DNA samples from 113 cases of human renal cell cancer were analyzed by sequence-specific polymerase chain reaction to determine the genotypic frequency of six different polymorphic loci on ERalpha gene (codon 10 T-->C, codon 87 G-->C, codon 243 C-->T, codon 325 C-->G, codon 594 G-->A, and intron 1 C-->T). The relative risk of variant genotype was calculated by comparison with 200 healthy controls. The results of this study demonstrate that the distribution of genotypes on codon 10 differs between renal cancer patients and healthy normal controls (p<0.05). The relative risk of the genotype 10C/C was calculated as 2.51. No differences in genotypes were observed at all other loci. We also analyzed DNA from pairs of cancerous and normal tissues from 96 cases of human renal cell cancer to characterize genotypic changes at these loci. Genotypic changes were detected in nine cancer samples on exon 1 (codons 10 and 87) of ERalpha, although none were detected at other regions. The present study demonstrates for the first time that codon 10 polymorphism on exon 1 of ERalpha may be involved in renal cancer risk.     

The obesity in bilateral ovariectomized rats is related to a decrease in the expression of leptin receptors in the brain.

We investigated the expression levels of leptin receptors in the brain of ovariectomized (OVX) rats. The mean expression level of ob mRNA in adipose tissues of OVX rats was significantly (P < 0.01) lower than that in the SHAM operation group rats, and the mean body weight of OVX rats was significantly (P < 0.01) greater than that in the SHAM group rats. However, there were no differences between serum leptin concentrations in these two groups. The mean level of leptin receptor (OB-R) mRNA expression in the brain tissue and the mean level of long form type OB-R (OB-RL) mRNA expression in the hypothalamus of the OVX rats were significantly (P < 0.05) lower than those in the SHAM group rats. These changes were cancelled by supplementation with 17 beta-estradiol in OVX rats. These results suggested that not only changes in the expression level of ob mRNA in adipose tissue and the serum leptin concentration but also changes in the OB-R mRNA in the brain are involved in the body weight increase in OVX rats and that a decrease in OB-R makes transmission of signals to suppress the amount of food intake difficult, thus leading to an increase in body weight.     

Origin of cortical microtubules organized at M/G1 interface: recruitment of tubulin from phragmoplast to nascent microtubules

The origin of cortical microtubules (CMTs) was investigated in transgenic BY-2 cells stably expressing a GFP (green fluorescent protein) -tubulin fusion protein (BY-GT16). In a previous study, we found that CMTs were initially organized in the perinuclear regions but then elongated to reach the cell cortex where they formed bright spots, and that the appearance of parallel MTs from the bright spots was followed by the appearance of transverse MTs (Kumagai et al., Plant Cell Physiol. 42, 723-732, 2001). In this study, we investigated the migration of tubulin to the reorganization sites of CMTs at the M/G1 interface. After synchronization of the BY-GT16 cells by aphidicolin, the localization of GFP-tubulin was monitored and analyzed by deconvolution microscopy. GFP-tubulin was found to accumulate on the nuclear surface near the cell plate at the final stage of phragmoplast collapse. Subsequently, GFP-tubulin accumulated again on the nuclear surface opposite the cell plate, where nascent MTs elongated to the cell cortex. The significance of these observations on the mode of CMT organization is discussed.     

Degradation of Endogenous Organic Acids Induced by Pi Uptake in Catharanthus roseus Cells: Involvement of the Biochemical pH-Stat

We have previously shown that inorganic orthophosphate (P_i)uptake by Catharanthus roseus cells proceeds by a proton/P_icotransport mechanism [Sakano (1990) Plant Physiol. 93: 479]that acidifies the cytoplasm [Sakano et al. (1992) Plant Physiol.99: 672]. In the present study, we analyzed changes in the contentof endogenous organic acids, carbon dioxide evolution, and oxygenconsumption upon P_i application. The results are consistentwith the operation of the biochemical pH-stat mechanism [Davies(1986) Physiol. Plant. 67: 702] during and after P_i uptake. (Received November 13, 1997; Accepted March 30, 1998)     

Effectiveness of weekly subcutaneous recombinant human erythropoietin administration for chemotherapy-induced anemia

The effects of weekly subcutaneousrecombinant human erythropoietin (r-hEPO)administration on anemia during chemotherapy includingcisplatin and 5-fluorouracil in patients with head andneck carcinomas were examined. Weekly subcutaneousr-hEPO administration in cancer patients has not beeninvestigated previously. Patients were treated withr-hEPO 100 IU/kg (2 patients), 200 IU/kg (6 patients),or 400 IU/kg (5 patients), or placebo, andeffectiveness was evaluated by monitoring hemoglobinconcentration changes after administration for 8weeks. Hemoglobin concentrations in all 3 r-hEPOdosage groups were higher than that in the controlgroup during chemotherapy. All r-hEPO doses producedimprovements in the anemia induced by chemotherapy;however, the 400 IU/kg dose was most effective. Therequirement for blood transfusions decreased inpatients receiving r-hEPO therapy, and no significantside-effects were associated with r-hEPOadministration. These results suggest thatchemotherapy-induced anemia can be prevented by weeklysubcutaneous r-hEPO administration.     

Synthesis of adiposin-1 and related compounds

The synthesis is described of adiposin-1 (2a), isolated from an α-d-glucosidase inhibitor complex, adiposin, produced by Streptomyces caluvs TM-521. The synthesis involved the coupling of 1,6-anhydro-4-O-(3,4-anhydro-α-d-galactopyranosyl)-β-d-glucopyranose (13) with the di-O-isopropylidene derivative (7) of dl-(1,4,$\text{6}\text{5}$)-4,5,6-trihydroxy-3-(hydroxymethyl)-2-cyclohexenylamine. All possible diastereoisomers of the secondary amine were isolated by chromatography on silica gel. Their structures were tentatively assigned on the basis of ¹H-n.m.r. spectroscopy and optical rotation. Likewise, both the core-structure (4) of adiposin and the saturated analog (22) of 2a were synthesized.     

Effects of hypergravity on expression of XTH genes in azuki bean epicotyls

Hypergravity produced by centrifugation caused inhibition of elongation growth and a decrease in the cell wall extensibility in azuki bean epicotyls ( Vigna angularis Ohwi et Ohashi). Also, hypergravity increased the molecular mass of xyloglucans, whereas it decreased xyloglucan-degrading activity in epicotyls. When the expression profiles of three xyloglucan endotransglucosylase/hydrolase ( XTH ) genes, VaXTHS4 , VaXTH1 and VaXTH2 , were analyzed under hypergravity conditions, the expression of VaXTHS4 , which shows only hydrolase activity, was downregulated in proportion to the logarithm of the magnitude of gravity (R = −0.94). However, the gene expression of VaXTH1 or VaXTH2 , which shows only transglucosylase activity, was not affected by gravitational conditions. When the seedlings that had been grown at 1  g were transferred to hypergravity conditions at 300  g , the downregulation of VaXTHS4 expression was detected within 1 h. By removal of hypergravity stimulus, VaXTHS4 expression was increased within 1 h. These results suggest that azuki bean epicotyls promptly regulate the expression level of only VaXTHS4 in response to gravity stimuli. The regulation of xyloglucan-hydrolyzing activity as a result of changes in VaXTHS4 expression may be involved in the regulation by gravity of molecular mass of xyloglucans, leading to modifications of cell wall mechanical properties and cell elongation. Lanthanum and gadolinium, potential blockers of mechanosensitive calcium ion permeable channels (mechanoreceptors), nullified the suppression of VaXTHS4 expression, suggesting that mechanoreceptors are responsible for inhibition by hypergravity of VaXTHS4 expression.     

Modification of chemical properties of cell walls by silicon and its role in regulation of the cell wall extensibility in oat leaves

Effects of silicon on the mechanical and chemical properties of cell walls in the second leaf of oat (Avena sativa L.) seedlings were investigated. The cell wall extensibility in the basal region of the second leaf was considerably higher than that in the middle and subapical regions. Externally applied silicon increased the cell wall extensibility in the basal region, but it did not affect the extensibility in the middle and subapical regions. The amounts of cell wall polysaccharides and phenolic compounds, such as diferulic acid (DFA) and ferulic acid (FA), per unit length were lower in the basal region than in the middle and subapical regions of the leaf, and silicon altered these amounts in the basal region. In this region, silicon decreased the amounts of matrix polymers and cellulose per unit length and of DFA and FA, both per unit length and unit matrix polymer content. Silicon treatment also lowered the activity of phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) in the basal region. In contrast, the amount of silicon in cell walls increased in response to silicon treatment in three regions. These results suggest that in the basal region, silicon reduces the net wall mass and the formation of phenolic acid-mediated cross-linkages between wall polysaccharides. Such modifications of wall architecture may be responsible for the silicon-induced increase in the cell wall extensibility in oat leaves.     

Differential expression of protein phosphatase type 1 isotypes and nucleolin during cell cycle arrest

In the present study, we examined the expression and cytolocalization of protein phosphatase type 1 (PP1) isoforms and nucleolin in human osteoblastic cell line MG63 cells at two boundaries in the cell cycle. We treated MG63 cells with hydroxyurea and nocodazole to arrest the cells at the G(1)/S and G(2)/M boundaries, respectively. As judged from the results of Western blot analysis, PP1 isoforms were expressed differently at each boundary of the cell cycle. Nucleolin was also shown to have a different expression pattern at each boundary. In the hydroxyurea-treated cells, nucleolus-like bodies were bigger in size and decreased in number compared with those in asynchronized cells. However, the subcellular localization of PP1s and nucleolin was not changed. Anti-nucleolin antibody interacted with 110-kDa and 95-kDa proteins present in asynchronized cells and in the cells treated with hydroxyurea. Treatment of the cells with nocodazole decreased the level of the 95-kDa form of nucleolin. In the nocodazole-treated cells, it was impossible to distinguish the distribution of each protein. The phosphorylation status of nucleolin in the cell cycle arrested samples was examined by 2D-IEF-PAGE followed by Western blot analysis. In the case of asynchronized cells or hydroxyurea-treated ones, nucleolin was located at a basic isoelectric point (dephosphorylated status); whereas in the G(2)/M arrest cells, the isoelectric point of nucleolin shifted to an acidic status, indicating that nucleolin was phosphorylated. The present results indicate that PP1 and nucleolin were differently expressed at G(1)/S and G(2)/M boundaries of the cell cycle and acted in a different fashion during cell-cycle progression.     

Dynamic intracellular reorganization of cytoskeletons and the vacuole in defense responses and hypersensitive cell death in plants

Plants have evolved various means for controlled and organized cell destruction, known as programmed cell death (PCD). In plant immune responses against microbial infection, hypersensitive cell death as a form of PCD is a crucial event to prevent the spread of biotrophic pathogens. Recent live cell imaging techniques have revealed dynamic features and significant roles of cytoskeletons and the vacuole during defense responses and the PCD. Actin microfilaments (MFs) focus on the infection sites and function as tracks for the polar transport of antimicrobial materials. To accomplish hypersensitive cell death, further dynamic changes in cytoskeletons are induced. MFs play a role in the structural and functional regulation of the vacuole, leading to execution of the PCD. We here overview spatiotemporal dynamic changes in the cytoskeletons and the vacuoles triggered by signals from pathogens, and propose a hypothetical model for MF-regulated vacuole-mediated PCD in plant immunity.