A case of clear cell variant of solid-pseudopapillary tumor of the pancreas in an adult male patient.

A clear cell variant of solid-pseudopapillary tumor (SPT) of the pancreas was initially reported in 2006 as a tumor that arose in the pancreatic body and tail in young adults; to date, only 4 cases of this entity have been reported. Here, we present the case of a 58-year-old man with clear cell variant of SPT with distinctive clinicopathologic features. The tumor was well demarcated, was 2.6 cm in size and mostly composed of multivacuolated clear cells with solid growth, and exhibited the characteristic immunohistochemical positivity of ß-catenin in the cytoplasm and nuclei of the neoplastic cells. In contrast to classical SPT with nuclear positivity, this case was negative for E-cadherin. Direct DNA sequencing of exon 3 of ß-catenin gene demonstrated a single amino acid substitution (serine to phenylalanine) in codon 37, which is the phosphorylation site by GSKß and frequently found in classical SPT. Electron microscopy demonstrated enlarged mitochondria and endoplasmic reticulum. Despite the fact that previous cases of clear cell variant of SPT arose mainly in the pancreatic body and tail in female young adults (age, 26-32 years), this case suggested that it is possible for a clear cell variant of SPT to arise in the pancreatic head in a middle-aged man. Because the recognition of the clear cell variant of SPT is important for the appropriate diagnosis of primary pancreatic tumor, the present case with its distinctive characteristics may provide new information for a more profound understanding of the pancreatic SPT.

Quantitative imaging of spontaneous neuromagnetic activity for assessing cerebral ischemia using sLORETA-qm.

To image cerebral neural activity in ischemic areas, we proposed a novel technique to analyze spontaneous neuromagnetic fields based on standardized low-resolution brain electromagnetic tomography modified for a quantifiable method (sLORETA-qm). Using a 160-channel whole-head-type magnetoencephalographic system, cerebral magnetic fields were obtained pre- and postoperatively from 5 patients with unilateral internal carotid artery occlusive disease and 16 age-matched healthy volunteers. For quantitative imaging, voxel-based time-averaged intensities of slow waves in 4 frequency bands (0.3-2 Hz, 2-4 Hz, 4-6 Hz and 6-8 Hz) were obtained by the proposed technique based on sLORETA-qm. Positron emission tomography with (15)O gas inhalation ((15)O-PET) was also performed in these patients to evaluate cerebral blood flow and metabolism. In all 5 patients, slow waves in every frequency band were distributed in the area of cerebrovascular insufficiency, as confirmed by (15)O-PET preoperatively. In 4 patients, slow-wave intensities in theta bands (4-6 Hz, 6-8 Hz) decreased postoperatively along with improvements in cerebral blood flow and metabolism, whereas delta bands (0.3-2 Hz, 2-4 Hz) showed no significant differences between pre- and postoperatively. One patient with deterioration of cerebral infarction after surgery showed marked increases in slow-wave intensities in delta bands (0.3-2 Hz, 2-4 Hz) postoperatively, with distribution close to the infarct region. The proposed quantitative imaging of spontaneous neuromagnetic fields enabled clear visualization and alternations of cerebral neural conditions in the ischemic area. This technique may offer a novel, non-invasive method for identifying cerebral ischemia, although further studies in a larger number of patients are warranted.

A case of central nervous system lymphomatoid granulomatosis; characteristics of PET imaging and pathological findings.

Lymphomatoid granulomatosis (LYG) in the central nervous system (CNS) is an uncommon lymphoproliferative disorder with low grade malignant potential. Here we report a case of CNS-LYG, in particular, its characteristics of radioisotope imaging and pathological findings. A 65-year-old man complained of visual disturbance and homonymous hemianopsia was designated. CT and MRI revealed an edematous, enhanced irregular and nodular lesion in the right occipital and parietal lobes. Although 18F-fluorodeoxyglucose (FDG)-positron emission tomography (PET) scan showed low uptake in the lesion, Methionine (MET)-PET scan indicated high uptake. Proton magnetic resonance spectroscopy ((1)H-MRS) at 3T revealed a decrease of the peak of the N-acetylaspartate (NAA), suggesting a possible neoplastic lesion. The patient was diagnosed with CNS-LYG based on the surgically removed material showing perivascular infiltration of CD3-positive small T-lymphocytes with granulomatous lesions. The post-operative steroid therapy was effective and the recurrence or exacerbation has not been observed by radiological imaging until now.

[Expression of cyclooxygenase (COX)-2 in astrocytic tumors and anti-tumor effects of selective COX-2 inhibitors].

Cyclooxygenase (COX)-2 of astrocytic tumors was studied by immunohistochemistry. COX-2 was expressed in 8 of 12 (75%) glioblastoma multiforme, 1 of 7 (14%) anaplastic astrocytoma, but none in astrocytoma. COX-2 was detected by an immnoblotting in 2 of 9 human glioblastoma cell lines (KNS42 and U138). In glioblastoma cell lines, NS398 and Etodolac inhibited cell proliferation and induced apoptosis. The result showed that COX-2 expression may be related with histological grades and COX-2 inhibitors will be one of promising therapeutic tools in human astrocytic tumors.

Computational analysis of isoform-specific signal regulation by CEACAM1-A cell adhesion molecule expressed in PC12 cells.

CEACAM1 is a signal-regulating, homophilic cell adhesion receptor system expressed in epithelia, vessel endothelia, and leukocytes. Here, we demonstrate that CEACAM1 is expressed also in PC12 cells, both as the common transmembrane isoforms, CEACAM1-L and CEACAM1-S, and as a novel, secreted, differentially spliced isoform. CEACAM1 can have both positive and negative effects on cell signaling. In an attempt to explain this dual behavior, we have initiated computational analysis of the signal-regulating effects of CEACAM1. This suggests that CEACAM1 can exert its signal-regulating activities by discriminating between binding of Src kinases and SHP phosphatases, respectively. Major factors that regulate this discrimination are the expression levels and expression ratios of transmembrane CEACAM1-L and CEACAM1-S, the concentration of secreted CEACAM1, and homophilic binding of CEACAM1 presented by neighboring cells.

Histone deacetylase inhibitors such as sodium butyrate and trichostatin A inhibit vascular endothelial growth factor (VEGF) secretion from human glioblastoma cells.

We investigated the effects of histone deacetylase (HDAC) inhibitors such as sodium butyrate (SB) and trichostatin A (TSA) on the expression of vascular endothelial growth factor (VEGF) by human glioblastoma T98G, U251MG, and U87MG cells. The glioblastoma cells secreted three VEGF isoforms, VEGF (189), (165), and (121), although the expression levels of VEGF differed between the cell types. Treatment with either 5mM SB or 100 ng/ml TSA reduced VEGF secretion in conditioned media and reduced VEGF mRNA expression. We also studied the expression of VEGF-B, -C, and -D mRNA in human glioblastoma cells and their modulation by HDAC inhibitors. The PCR products of VEGF-B (357bp), VEGF-C (501bp), and VEGF-D (484bp) were amplified in all glioblastoma cells examined. Treatment with SB reduced the expression of VEGF-D mRNA in U251MG cells and the expression of VEGF-B mRNA in U87MG cells. TSA treatment reduced the expression of VEGF-D in U251MG cells. These results suggest that HDAC inhibitors reduce VEGF secretion and modulate the expression of the other VEGF family members, and therefore may inhibit angiogenesis in glioblastoma tissues.

Correlation between positron emission tomography findings and glucose transporter 1, 3 and L-type amino acid transporter 1 mRNA expression in primary central nervous system lymphomas.

Primary central nervous system lymphoma (PCNSL) is an aggressive form of non-Hodgkin lymphoma with a poor prognosis. [18F] 2-fluoro-2-deoxy-D-glucose (FDG) and L-(methyl-11C)-methionine (MET) are the most widely used tracers in oncological positron emission tomography studies for PCNSL and commonly identify hypermetabolic lesions through increased uptake of FDG and MET. However, the mechanisms underlying the uptake of FDG and MET in PCNSL have not been clearly determined. The present study aimed to investigate the mRNA expression levels of glucose transporter (GLUT)1, GLUT3 and L-type amino acid transporter 1 (LAT1) in resected PCNSL specimens, in order to identify whether these transporters are associated with the increased uptake of FDG and MET. A total of 7 patients diagnosed with PCNSL were investigated. The uptake of FDG and MET by the tumors was evaluated based on the maximum standardized uptake value (SUVmax). The quantity of GLUT1, GLUT3 and LAT1 mRNA in the PCNSL specimens was measured to determine whether GLUT1, GLUT3 and/or LAT1 are involved in the increased uptake of FDG and MET in PCNSL. Furthermore, microvessel density (MVD) and cell density (CD) were measured in all the cases. Our results indicated that the expression of GLUT3, but not GLUT1, was significantly correlated with FDG SUVmax and the expression of LAT1 was significantly correlated with MET SUVmax. However, neither MVD nor CD were found to be significantly associated with the uptake of FDG and MET. GLUT3 was identified as a key determinant of FDG accumulation, whereas LAT1 was a key determinant of MET accumulation in PCNSL. Therefore, GLUT3 and LAT1 may represent potential targets for the future development of novel therapeutic agents for PCNSL.

Antitumor effects of a cyclooxygenase-2 inhibitor, meloxicam, alone and in combination with radiation and/or 5-fluorouracil in cultured tumor cells.

To ascertain whether meloxicam used in a clinical setting as a non-steroidal anti-inflammatory drug (NSAID) warrants preclinical in vivo evaluation as an anticancer agent, we investigated its antitumor effects alone and in combination with radiation and/or 5-fluorouracil (5-FU) in cultured cells. Seven cell lines were examined for cyclooxygenase-2 (COX-2) protein expression by immunoblot analysis, and the HeLaS3, SCCVII and EMT6 cell lines were selected, expressing relatively high, intermediate, and relatively low COX-2 levels, respectively. Antitumor effects were examined using a colony assay. Among the three cell lines, the effect of meloxicam alone was strongest in SCCVII cells. With 24 h of drug exposure, meloxicam at concentrations of 250 and 1250 µM had a definite antitumor effect, dependent on the drug exposure time. The effect of meloxicam in combination with radiation and/or 5-FU was also investigated in the SCCVII cells. At a meloxicam concentration of 250 µM, the antitumor effect in combination with radiation or 5-FU was increased compared to the effect of radiation or 5-FU alone; however, the combined effect appeared to be additive. At lower concentrations, meloxicam had no radiosensitizing effect, nor did it enhance the effect of 5-FU. A meloxicam concentration of 250 µM is considerably higher than concentrations obtained in humans taking meloxicam as an NSAID. In conclusion, the antitumor effect of meloxicam was not correlated with the level of COX-2 protein expression. The effect of meloxicam in combination with radiation and/or 5-FU appeared to be additive. To evaluate the possibility of using meloxicam as an anticancer agent, in vivo investigations at clinically relevant drug dose levels are required.

Histone deacetylase inhibitor, FK228, induces apoptosis and suppresses cell proliferation of human glioblastoma cells in vitro and in vivo.

We investigated the effects of FK228 on cell proliferation and apoptosis against human glioblastoma (GM) T98G, U251MG, and U87MG cells. Upon exposure to FK228, cell proliferation was inhibited, and apoptosis detected by the cleavage of CPP32 was induced. FK228 increased the expression levels of p21 (WAF-1) and of pro-apoptotic Bad protein in all GM cells. Furthermore, FK228 treatment also reduced the anti-apoptotic protein Bcl-xL in all GM cells and anti-apoptotic Bcl-2 in U87MG cells, thereby shifting the cellular equilibrium from life to death. An increased accumulation of histone H4 was detected in the p21 (WAF-1) promoter and the structural gene (exon 2) and the Bad structural gene (exon 2 and 3) upon treatment with FK228, as assessed by chromatin immunoprecipitation (ChIP) assay. Thus, the results indicated that an increased expression of p21 (WAF1) and Bad due to FK228 is regulated, at least in part, by the degree of acetylation of the gene-associated histone. We also found that FK228 inhibits cellular invasiveness and decreases MMP-2 activity. In addition, the growth of transplanted human GM m-3 cells into the subcutaneous tissue of hereditary athymic mice was significantly inhibited, and apoptosis was induced with FK228 treatment. The results suggested that FK228 might be useful in the treatment of human GM, although further studies will be needed.