Celecoxib upregulates endoplasmic reticulum chaperones that inhibit celecoxib-induced apoptosis in human gastric cells.

Nonsteroidal anti-inflammatory drugs (NSAIDs) induce apoptosis in cancer cells and this effect is involved in their antitumor activity. We recently demonstrated that NSAIDs upregulate GRP78, an endoplasmic reticulum (ER) chaperone, in gastric mucosal cells in primary culture. In the present study, induction of ER chaperones by NSAIDs and the effect of those chaperones on NSAID-induced apoptosis were examined in human gastric carcinoma cells. Celecoxib, an NSAID, upregulated ER chaperones (GRP78 and its cochaperones ERdj3 and ERdj4) but also C/EBP homologous transcription factor (CHOP), a transcription factor involved in apoptosis. Celecoxib also upregulated GRP78 in xenograft tumors, accompanying with the suppression of tumor growth in nude mice. Celecoxib caused phosphorylation of eukaryotic translation initiation factor 2 kinase (PERK) and eukaryotic initiation factor-2alpha (eIF2alpha) and production of activating transcription factor (ATF)4 mRNA. Suppression of ATF4 expression by small interfering RNA (siRNA) partially inhibited the celecoxib-dependent upregulation of GRP78. Celecoxib increased the intracellular Ca2+ concentration, while 1,2-bis(2-aminophenoxy)ethane-N,N,N'N'-tetraacetic acid, an intracellular Ca2+ chelator, inhibited the upregulation of GRP78 and ATF4. These results suggest that the Ca2+-dependent activation of the PERK-eIF2alpha-ATF4 pathway is involved in the upregulation of ER chaperones by celecoxib. Overexpression of GRP78 partially suppressed the apoptosis and induction of CHOP in the presence of celecoxib and this suppression was stimulated by coexpression of either ERdj3 or ERdj4. On the other hand, suppression of GRP78 expression by siRNA drastically stimulated cellular apoptosis and production of CHOP in the presence of celecoxib. These results show that upregulation of ER chaperones by celecoxib protects cancer cells from celecoxib-induced apoptosis, thus may decrease the potential antitumor activity of celecoxib.

Endoplasmic reticulum stress response is involved in nonsteroidal anti-inflammatory drug-induced apoptosis.

Apoptosis induced by nonsteroidal anti-inflammatory drugs (NSAIDs) is involved not only in the production of NSAID-induced gastric lesions but also in the antitumor activity of these drugs. The endoplasmic reticulum (ER) stress response is a cellular mechanism that aids in protecting the ER against ER stressors and is involved in ER stressor-induced apoptosis. Here, we examine the relationship between this response and NSAID-induced apoptosis in cultured guinea-pig gastric mucosal cells. Exposure of cells to indomethacin, a commonly used NSAID, induced GRP78 as well as CHOP, a transcription factor involved in apoptosis. Three factors that positively regulate CHOP expression (ATF6, ATF4 and XBP-1) were activated and/or induced by indomethacin. NSAIDs other than indomethacin (diclofenac, ibuprofen and celecoxib) also induced CHOP. Monitoring of the transcriptional activities of ATF6 and CHOP by luciferase assay revealed that both were stimulated in the presence of indomethacin. Furthermore, indomethacin-induced apoptosis was suppressed in cultured guinea-pig gastric mucosal cells by expression of the dominant-negative form of CHOP, or in peritoneal macrophages from CHOP-deficient mice. These results suggest that ER stress response-related proteins, particularly CHOP, are involved in NSAID-induced apoptosis.

Rapid adsorption pretreatment with submicrometre powdered activated carbon particles before microfiltration.

Manufacturer-supplied powdered activated carbon (PAC) was ground to produce submicrometre particles (0.8 and 0.6 m median diameter) for use as an adsorbent before microfiltration (MF) for drinking water treatment. Batch tests revealed that the microground PAC adsorbed natural organic matter (NOM) much more rapidly and had a higher adsorptive capacity than ordinary PAC. The water samples pretreated with the submicrometre PAC were subjected to MF, and the results of experiments with different PAC contact times revealed that a 1 min retention time was sufficient for adsorptive removal of NOM. The use of submicrometre PAC permitted not only shorter PAC contact times but also a 75% reduction in dose.

Role of the amino-terminal region of the DnaA protein in opening of the duplex DNA at the oriC region.

We report in this paper that the amino acid residues Ile-26 and Leu-40 of the DnaA protein are essential for the DNA replication activity in vitro. Lines of evidence to support this conclusion are as follows. Variants of the DnaA protein containing either an Ile-26-Ser or Leu-40-Ser replacement were unable to support oriC DNA replication in vitro. Though the mutant DnaA proteins retained the capability to bind oriC DNA, they were unable to open the duplex DNA at oriC. Based on these and other results, we conclude that the N-terminal region of the DnaA protein is involved in the oligomerization of this protein, an essential step for the duplex opening activity at oriC.

Interaction of metallopyrazoliumylporphyrins with calf thymus DNA.

The interaction of transition metal complexes of cationic porphyrins bearing five membered rings, meso-tetrakis(1,2-dimethylpyrazolium-4-yl)porphyrin (MPzP, M=Mn(III), Ni(II), Cu(II) or Zn(II)), with calf thymus DNA (ctDNA) has been studied. Metalloporphyrins NiPzP and CuPzP are intercalated into the 5'GC3' step of ctDNA. MnPzP is bound edge-on at the 5'TA3' step of the minor groove of ctDNA, while ZnPzP is bound face-on at the 5'TA3' step of the major groove of ctDNA. The binding constants of the metalloporphyrins to ctDNA range from 1.05x10(5) to 2.66x10(6) M(-1) and are comparable to those of other reported cationic porphyrins. The binding process of the metallopyrazoliumylporphyrins to ctDNA is endothermic and entropically driven. These results have revealed that the kind of central metal ions of metalloporphyrins influences the binding characteristics of the porphyrin to DNA.

A morphological study of liver lesions in Xenopus larvae exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) with special reference to apoptosis of hepatocytes.

Edema formation is a consistent feature of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) poisoning in experimental animals. Xenopus embryos exposed to 200 ppb of TCDD for 5 days from shortly after fertilization to early larval stage developed edema of the head, thorax, and abdomen, including ascites, from several days after the end of exposure. There has been no reports on liver lesions in TCDD-exposed anuran larvae. To elucidate the participation of liver in the edema formation, light and electron microscopic alterations in the livers from larvae that developed edema were examined. The marked change induced by TCDD was degeneration of the hepatocytes. Three types of degenerating hepatocytes were distinguished. The first type showed morphological features characteristic of apoptosis, including peripherally aggregated nuclear chromatin and overall cytoplasmic condensation; the cytoplasmic organelles retained their integrity and cytoplasmic blebbing. A considerable number of degenerating hepatocytes undergoing apoptosis and numerous apoptotic bodies derived from hepatocytes were observed by electron microscopy. The second type could not be determined as to which type of cell death it belonged to, and the third type was necrosis. Other alterations consisted of disturbances of the usual meshwork architecture of the liver, enlargements of bile canaliculi and the space of Disse, lipid accumulation, and appearance of phagocytizing macrophages. These morphological alterations in the liver generally correlated with the severity of edema with a few exception. These findings suggest that depressed hepatic function mainly due to hepatocyte death participates in the edema formation.

Apoptosis of the intestinal principal cells of Xenopus larvae exposed to 2,3,7,8-tetrachlorodibenzo-p-dioxin.

In our previous work using paraffin-embedded sections, we determined that Xenopus larvae exposed to 200 ppb 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) for 5 days from shortly after fertilization to the early larval stage showed a shortening of the digestive tract and a loss of mucosal epithelium cells due to exfoliation into the gut cavity. In the current study, we ultrastructurally examined the mucosal epithelium of the gut of TCDD-exposed Xenopus larvae 12 days after fertilization. Exfoliated cell structures at the villus tip and in the lumen were equipped with a microvillus portion and occasionally had terminal web-like structures seen by ultramicroscopy. As these exfoliated structures had nuclear fragments with condensed chromatin, they were considered to be apoptotic bodies derived from the principal cells of the epithelium. In addition, many membrane-bound cell fragments-identified as apoptotic bodies derived from the principal cells based on their ultrastructural features-were observed at the basal side of the mucosal epithelium. These apoptotic bodies were phagocytized and digested chiefly by the neighboring intact principal cells. No such cells and/or cell fragments showing apoptotic features were observed in the controls. Our observations indicate that marked apoptosis occurs in the intestinal principal cells of TCDD-exposed larvae, which may result in the shortening of the gut.

Fluorescent molecular sensory system based on bis pyrene-modified gamma-cyclodextrin dimer for steroids and endocrine disruptors.

A gamma-cyclodextrin dimer modified with two pyrene moieties, 6-(2-pyrenebutylate-aminoethyl)pyrenebutylate-amino-6-deoxy-bis-gamma-cyclodextrin, has been synthesized in the presence of N,N'-dicyclohexycarbodiimide from gamma-cyciodextrin dimer linked with ethylenediamine at an upper rim. The sensing ability and binding property of the titled dimer were investigated for bile acids and endocrine disruptors. This cyclodextrin dimer showed both monomer and excimer fluorescence; the guest-induced emissions were observed as increases or decreases depending on the guest. The values deltaI(m)/I0(m) and deltaI(ex)/I0(ex), where I0(m) and I(m) are fluorescence intensities of monomer emission in the absence and presence of a guest and I0(ex) and I(ex) are those of excimer emission and deltaI(m) and deltaI(ex) were I(m) - I0(m) and I(ex) - I0(ex), respectively, were used as a parameter of sensitivity. This host exhibited highly sensitive molecular recognition ability for bile acids and endocrine disruptors, in which the sensing parameters obtained from monomer emission were plus or minus values, whereas the parameters obtained as excimer emission were minus ones. The behavior of the appended moieties of the host during a host-guest complexation was studied by induced circular dichroism (ICD) and fluorescence spectra. The ICD intensities of the titled dimer were decreased upon an addition of a guest. The guest-induced variations in the fluorescence and ICD intensity suggest that the appended moieties move by altering the spatial relationship in the hydrophobic space between two linked cyclodextrins.

[Case of aneurysmal bone cyst of the skull].

A case of aneurysmal bone cyst of the right temporal bone was reported. The patient was a 36-year-old male who was admitted to our hospital with complaints of decreased right hearing and transient impairment of the right vision. A large tumor was palpated on the right temporal bone. Neurological examinations revealed right auditory loss, along with right facial weakness of peripheral type, and minimal pyramidal signs on the right side. The results of the laboratory examination proved to be normal. Neuroradiological examinations tended to be quite impressive. Plain x-ray films of the skull showed a blow out appearance of the right temporal bone and a bone decay in the right middle fossa, the right anterior clinoid process, and the posterior half of the right zygomatic arch. Angiograms revealed a right temporal extradural mass lesion without vascularity. CT scans showed a moderately enhanced mass lesion of soap bubble appearance in the right middle fossa. Surgical treatment was done under the diagnosis of extradural bone tumor. The operative findings disclosed many cysts containing bloody fluid and xanthochromic fluid. Numerous multinucleated giant cells, spindle cells, and foam cells were found in the microscopic examination. On the basis of macroscopic and microscopic findings, the patient was diagnosed as having an aneurysmal bone cyst. The aneurysmal bone cyst of the skull is very rare and sixteen cases have been reported in detail. This case had two interesting points, one was the transient impairment of visual acuity and the other was the CT findings.(ABSTRACT TRUNCATED AT 250 WORDS)

[High-resolution ultrasonography in cancer diagnosis--advances and indication of intraluminal sonography].

The present communication deals with recent developments in endoscopic sonography with special reference to the diagnosis of cancer of the upper abdominal organs. Examinations were carried out by an endoscope with a mechanical radial scanner, an Olympus GF UM1 and UM2, LPS UM1. Confirmed diagnostic applications are staging of esophageal and gastric cancer, diagnosis of submucosal tumors of the G.I. tract and differentiation between benign and malignant ulcer of the mucosa. The method also has excellent diagnostic application to malignancies involving organs adjacent to the G.I. tract, such as the mediastinum, retroperitoneum including the pancreas and adrenals, and the left lobe of the liver. Laparoscopic sonography, another endoscope-guided sonography involving the sonolaparoscope, revealed excellent ability to visualize and discriminate between benign and malignant small tumors in the liver and also the gallbladder and pancreas. The method is extremely helpful when surgical intervention is considered. Detection rate of hepatocellular cancer reached almost 90% of cases examined.