Phenylarsine oxide (PAO) more intensely induces apoptosis in acute promyelocytic leukemia and As2O3-resistant APL cell lines than As2O3 by activating the mitochondrial pathway

We studied the cytotoxic effect of an organic arsenical compound, phenylarsine oxide (PAO) on an acute promyelocytic leukemia (APL) cell line (NB4) and an As₂O₃-resistant NB4 subline (NB4/As). Cell growth was inhibited by 50% (IC₅₀) upon 2-day treatment with As₂O₃ or PAO at 0.54 and 0.06 μM, respectively in NB4 cells (P = 0.025), and 2.80 and 0.08 μM, respectively in NB4/As (P = 0.030). 0.1 μM PAO increased the proportion of hypodiploid cells (50.3%) by a greater degree than the same dose of As₂O₃ (3.8%) in NB4 cells. In NB4 cells, 0.1 μM PAO reduced the mitochondrial transmembrane potential (20.5% in a PI^negative-Rhodamine123^low fraction) by a greater degree than 1 μM As₂O₃ (7.1%). Western blotting showed that 0.1 μM PAO downregulated the expression of both Bcl-2 and Bcl-X_L proteins, whereas I μM As₂O₃ downregulated only Bcl-2 expression. These results suggest that the cytotoxic effect of PAO on an APL cell line and As₂O₃-resistant subline is significantly higher than that of As₂O₃. PAO-induced apoptosis seems to be related to the activation of the mitochondrial pathway and downregulation of both Bcl-2 and Bcl-X_L. PAO is a considerable agent for relapsed/refractory APL and for purging APL cells following stem cell transplantation.     

Prognostic significance of surface markers expressed in multiple myeloma: CD56 and other antigens

Multiple myeloma (MM) is characterized by increased numbers of malignant plasma cells. Plasma cells, that represent the terminal differentiation of B lymphocytes, have considerable heterogeneity of surface markers expressed on them. Some studies showed the prognostic significance of several immunophenotypic molecules on MM cells. Here, we review several surface markers related to their prognostic significance in MM patients. We also report that CD56-negative MM is the unique entity characterized by poor prognosis with high incidence of extramedullary disease, Bence Jones protein, renal insufficiency, thrombocytopenia and plasmablastic morphology.     

Thymidine phosphorylase and dihydropyrimidine dehydrogenase expression in hepatocellular carcinoma and metastatic liver cancer

Thymidine phosphorylase (TP) and dihydropyrimidine dehydrogenase (DPD) are considered to be key enzymes affecting the prognosis for patients with various cancers. We tried to prove the correlation of TP and DPD expression in hepatocellular carcinoma (HCC) and liver metastasis. We quantified TP and DPD levels by an enzyme-linked immunosorbent assay (ELISA) in the tumor (T) and adjacent normal tissue (N) obtained from 8 HCC patients, and 11 liver metastasis patients together with 9 of their primary cancers. TP levels were higher in the primary cancer, liver metastasis, and HCC compared with each adjacent tissue. TP levels were higher in HCC than in liver metastasis, and TP levels in the adjacent tissues of HCC were also higher than those in adjacent tissues of liver metastasis. TP levels were higher in liver metastasis than in primary cancer, and TP levels in adjacent tissues of liver metastasis were also higher than those in adjacent tissues of primary cancer. However, there were no differences in TP T/N ratio between HCC and liver metastasis, and between primary cancer and liver metastasis. DPD levels were lower in the liver metastasis compared with the adjacent liver tissues, and DPD levels in liver metastasis or its adjacent liver tissues were higher than those in primary cancer or its adjacent tissues. There were no differences in DPD T/N ratio between HCC and liver metastasis, and between primary cancer and liver metastasis. Thus, we demonstrated that TP was highly expressed in liver malignancy. We may be able to increase the success of anticancer chemotherapy for liver malignancy while decreasing the side effects by analysis of T/N ratios in TP, DPD, and TP/DPD in addition to TP expression.     

Temporal changes in the distribution and number of macrophage-lineage cells in the periodontal membrane of the rat molar in response to experimental tooth movement

In order to evaluate the possible role of macrophages in the remodelling of periodontal tissue in response to tooth movement, temporal changes in the number and distribution of macrophage-lineage cells in the periodontal membrane of the rat molar tooth after experimental tooth movement were examined immunohistochemically using four anti-rat monoclonal antibodies: ED1 (anti-monocyte/macrophage-lineage cells and dendritic cells), ED2 (anti-resident macrophages), KI-M2R (anti-tissue macrophages), and OX6 (anti-class II molecules). The right maxillary first molar tooth of Wistar rats was moved mesially by a closed-coil spring for 1, 3, 5, or 7 days. Sham-treated rats wearing an inactivated appliance for each experimental period and entirely untreated rats were used as controls. Alternate horizontal serial cryostat sections were cut and incubated with antibodies to ED1, ED2, KI-M2R, and OX6. In addition, cells immunopositive for each monoclonal antibody in the periodontal membrane during tooth movement were analysed on the tension and pressure sides. In the control rats, large numbers of cells positively stained with each monoclonal antibody were distributed throughout the periodontal membrane surrounding the distobuccal root. At 1 day after experimental tooth movement, the number of immunopositive cells obtained with all four monoclonal antibodies decreased as compared with those of the control on the mesial/pressure side. During the later experimental time periods, ED1- and OX6-positive cells in the periodontal membrane of this side were significantly increased in number compared with controls, whereas the density and distribution pattern of cells positive with ED2 or KI-M2R remained unchanged. On the mesial/pressure side, which underwent hyalinization, a marked accumulation of OX6- and ED1-reactive cells, but not of ED2- or KI-M2R-reactive cells, was frequently observed in the area of the hyalinized tissue at 5-7 days after the start of tooth movement. On the distal/tension side, no particular change in the distribution of immunopositive cells obtained with any antibody was detected throughout the experimental periods, with the exception that there was a significant increase in the number of ED1-positive cells and in of OX6-positive cells at 1 and 7 days, respectively, after the start of tooth movement. These results suggest that after the start of tooth movement OX6- and ED1-positive cells, which are mostly exudative macrophages, but not ED2- and KI-M2R-positive cells, i.e., resident macrophages, may be actively engaged in bone resorption and the remodelling of tissues on the pressure side of the periodontal membrane.     

Detection of Alzheimer’s disease-related neuroinflammation by a PET ligand selective for glial versus vascular translocator protein

A substantial and constitutive expression of translocator protein (TSPO) in cerebral blood vessels hampers the sensitive detection of neuroinflammation characterized by greatly induced TSPO expression in activated glia. Here, we conducted in vivo positron emission tomography (PET) and in vitro autoradiographic imaging of normal and TSPO-deficient mouse brains to compare the binding properties of ¹⁸F-FEBMP, a relatively novel TSPO radioligand developed for human studies based on its insensitivity to a common polymorphism, with ¹¹C-PK11195, as well as other commonly used TSPO radioligands including ¹¹C-PBR28, ¹¹C-Ac5216 and ¹⁸F-FEDAA1106. TSPO in cerebral vessels of normal mice was found to provide a major binding site for ¹¹C-PK11195, ¹¹C-PBR28 and ¹⁸F-FEDAA1106, in contrast to no overt specific binding of ¹⁸F-FEBMP and ¹¹C-Ac5216 to this vascular component. In addition, ¹⁸F-FEBMP yielded PET images of microglial TSPO with a higher contrast than ¹¹C-PK11195 in a tau transgenic mouse modeling Alzheimer’s disease (AD) and allied neurodegenerative tauopathies. Moreover, TSPO expression examined by immunoblotting was significantly increased in AD brains compared with healthy controls, and was well correlated with the autoradiographic binding of ¹⁸F-FEBMP but not ¹¹C-PK11195. Our findings support the potential advantage of comparatively glial TSPO-selective radioligands such as ¹⁸F-FEBMP for PET imaging of inflammatory glial cells.     

Changes in Portal Systemic Pressure Gradient After Balloon-Occluded Retrograde Transvenous Obliteration of Gastric Varices and Aggravation of Esophageal Varices

The purpose of this study was to evaluate change in the portal systemic pressure gradient (PSPG) following balloon-occluded retrograde transvenous obliteration (BRTO) and the aggravation of esophageal varices. The PSPG was monitored before and after BRTO in 19 patients. PSPG changes were obtained by subtracting the PSPG before BRTO from that after BRTO. The development of outflow vessels (e.g., left inferior phrenic vein) was classified into two grades: Grade 1, BRTO alone; and Grade 2, coil embolization plus BRTO. After confirming demonstration of the whole gastric varices on angiography and computed tomography, BRTO was conducted using a 5% ethanolamine-iopamidol mixture. Endoscopy was performed to evaluate gastric and esophageal varices before, within 1 month, and 3–6 months after BRTO. Eradication of gastric varices was obtained in all patients and aggravation of esophageal varices was seen in 11 patients. The PSPG was significantly elevated by BRTO (p = 0.0362). The PSPG was significantly elevated in patients with Grade 2 compared with those with Grade 1 (7.7 ± 3.7 vs. 3.3 ± 4.3 mmHg, respectively; p = 0.0314) and in those with esophageal varices before treatment compared with those without (7.4 ± 4.0 vs. 3.2 ± 3.9 mmHg, respectively; p = 0.0482). The cumulative aggravation rate of esophageal varices was significantly higher in 11 patients with a PSPG elevation >5 mmHg than in 8 patients with one of ≤5 mmHg (p = 0.0105). In conclusion, BRTO induced a significant elevation in PSPG, with the degree of elevation influencing the aggravation of esophageal varices following BRTO.     

Downregulation of Tie2 gene by a novel antitumor sulfolipid, 3'-sulfoquinovosyl-1'-monoacylglycerol, targeting angiogenesis

We previously reported that 3'-sulfoquinovosyl-1'-monoacylglycerol (SQMG) was effective in suppressing the growth of solid tumors due to hemorrhagic necrosis in vivo . In the present study, we investigated the antiangiogenic effect of SQMG. In vivo assessment of antitumor assays showed that some tumor cell lines, but not others, were sensitive to SQMG. Microscopic study suggested that in SQMG-sensitive tumors, but not SQMG-resistant tumors, angiogenesis was reduced. We next investigated gene expression relating to angiogenesis in tumor tissues by quantitative real-time polymerase chain reaction. Consequently, although vascular endothelial growth factor gene expression was not detected with significant differences among the cases, significant downregulation of Tie2 gene expression was observed in all SQMG-sensitive tumors as compared with controls, but not in SQMG-resistant tumors. These data suggested that the antitumor effects of SQMG could be attributed to antiangiogenic effects, possibly via the downregulation of Tie2 gene expression in SQMG-sensitive tumors. ( Cancer Sci 2008; 99: 1063–1070)     

Interference by adrenaline with chondrogenic differentiation through suppression of gene transactivation mediated by Sox9 family members

In contrast to osteoblasts, little attention has been paid to the functional expression of adrenergic signaling machineries in chondrocytes. Expression of mRNA was for the first time demonstrated for different adrenergic receptor (AdR) subtypes in chondrogenic ATDC5 cells and mouse metatarsals isolated before vascularization in culture, but not for other molecules related to adrenergic signaling. In neonatal mouse tibial sections, β₂AdR and α_2aAdR mRNA expression was found in chondrocytes at different developmental stages by in situ hybridization. Exposure to adrenaline significantly suppressed expression of several maturation markers through the cAMP/protein kinase A pathway activated by β₂AdR without affecting cellular proliferation in both cultured ATDC5 cells and metatarsals. Adrenaline also significantly inhibited gene transactivation by sry-type HMG box 9 (Sox9) family members essential for chondrogenic differentiation in a manner prevented by the general βAdR antagonist propranolol, with a concomitant significant decrease in the levels of Sox6 mRNA and corresponding protein, in ATDC5 cells and primary cultured mouse costal chondrocytes. Systemic administration of propranolol significantly promoted the increased expression of mRNA for collagen I and collagen X, but not for collagen II, in callus of fractured femur in mice. These results suggest that adrenaline may interfere with chondrogenic differentiation through downregulation of Sox6 expression for subsequent suppression of gene transactivation mediated by Sox9 family members after activation of β₂AdR expressed by chondrocytes.