Bortezomib reduces the tumorigenicity of multiple myeloma via downregulation of upregulated targets in clonogenic side population cells.

Side population (SP) cells in cancers, including multiple myeloma, exhibit tumor-initiating characteristics. In the present study, we isolated SP cells from human myeloma cell lines and primary tumors to detect potential therapeutic targets specifically expressed in SP cells. We found that SP cells from myeloma cell lines (RPMI 8226, AMO1, KMS-12-BM, KMS-11) express CD138 and that non-SP cells include a CD138-negative population. Serial transplantation of SP and non-SP cells into NOD/Shi-scid IL-2γnul mice revealed that clonogenic myeloma SP cells are highly tumorigenic and possess a capacity for self-renewal. Gene expression analysis showed that SP cells from five MM cell lines (RPMI 8226, AMO1, KMS-12-BM, KMS-11, JJN3) express genes involved in the cell cycle and mitosis (e.g., CCNB1, CDC25C, CDC2, BIRC5, CENPE, SKA1, AURKB, KIFs, TOP2A, ASPM), polycomb (e.g., EZH2, EPC1) and ubiquitin-proteasome (e.g., UBE2D3, UBE3C, PSMA5) more strongly than do non-SP cells. Moreover, CCNB1, AURKB, EZH2 and PSMA5 were also upregulated in the SPs from eight primary myeloma samples. On that basis, we used an aurora kinase inhibitor (VX-680) and a proteasome inhibitor (bortezomib) with RPMI 8226 and AMO1 cells to determine whether these agents could be used to selectively target the myeloma SP. We found that both these drugs reduced the SP fraction, though bortezomib did so more effectively than VX-680 due to its ability to reduce levels of both phospho-histone H3 (p-hist. H3) and EZH2; VX-680 reduced only p-hist. H3. This is the first report to show that certain oncogenes are specifically expressed in the myeloma SP, and that bortezomib effectively downregulates expression of their products. Our approach may be useful for screening new agents with which to target a cell population possessing strong tumor initiating potential in multiple myeloma.

Enzymatic characterization of germination-specific cysteine protease-1 expressed transiently in cotyledons during the early phase of germination.

Papain-like cysteine protease activity that shows a unique transient expression profile in cotyledons of daikon radish during germination was detected. The enzyme showed a distinct elution pattern on DEAE-cellulose compared with cathepsin B-like and Responsive to dessication-21 cysteine protease. Although this activity was not detected in seed prior to imbibition, the activity increased markedly and reached a maximum at 2 days after imbibition and then decreased rapidly and completely disappeared after 5 days. Using cystatin-Sepharose, the 26 kDa cysteine protease (DRCP26) was isolated from cotyledons at 2 days after imbibition. The deduced amino acid sequence from the cDNA nucleotide sequence indicated that DRCP26 is an orthologue of Arabidopsis unidentified protein, germination-specific cysteine protease-1, belonging to the C1 family of cysteine protease predicted from genetic information. In an effort to characterize the enzymatic properties of DRCP26, the enzyme was purified to homogeneity from cotyledons at 48 h after imbibition. The best synthetic substrate for the enzyme was carbobenzoxy-Phe-Arg-4-methylcoumaryl-7-amide. All model peptides were digested to small peptides by the enzyme, suggesting that DRCP26 possesses broad cleavage specificity. These results indicated that DRCP26 plays a role in the mobilization of storage proteins in the early phase of seed germination.

A synthetic double-stranded RNA, poly I:C, induces a rapid apoptosis of human CD34(+) cells.

Toll-like receptor 3 (TLR3), retinoic acid-inducible gene I, and melanoma differentiation-associated antigen 5 (RIG-I/MDA-5) helicases are known to sense double-stranded RNA (dsRNA) virus and initiate antiviral responses, such as production of type-I interferons (IFNs). Recognition of dsRNA by TLR3 or RIG-I/MDA-5 is cell-type-dependent and recent studies have shown a direct link between TLRs and hematopoiesis. We hypothesized that viral dsRNA recognized by either TLR3 or RIG-I/MDA-5, affects the growth of human hematopoietic stem/progenitor cells. Here we show that polyinosinic polycytidylic acid (poly I:C)-mediated very rapid apoptosis occurs within 1 hour in CD34(+) cells in a dose-dependent manner. Polyadenylic-polyuridylic acid, another synthetic dsRNA that signals only through TLR3, had no effect. Poly I:C-LMW/LyoVec, a complex between low molecular-weight poly I:C and the transfection reagent LyoVec, which signals only through RIG-I/MDA-5, induces apoptosis of CD34(+) cells. A strong and sustained upregulation of messenger RNA and protein levels of Noxa, a proapoptotic BH3-only protein that can be induced by RIG-I/MDA-5 pathway, is found in CD34(+) cells treated by poly I:C. Although poly I:C upregulates type-I IFNs in CD34(+) cells, neither exogenous IFN-α nor IFN-ß induces rapid apoptosis in CD34(+) cells and neutralization or blocking of type-I IFN receptor does not rescue CD34(+) cells, whereas Z-VAD, a pan-caspase inhibitor, rescues the cells from apoptosis. These results suggest that RIG-I/MDA-5, but not TLR3, signaling triggers poly I:C-induced rapid apoptosis of human CD34(+) cells, which will provide an insight into the mechanisms of dsRNA virus-mediated hematopoietic disorders.

Aberrant overexpression of microRNAs activate AKT signaling via down-regulation of tumor suppressors in natural killer-cell lymphoma/leukemia.

The gene(s) responsible for natural killer (NK)-cell lymphoma/leukemia have not been identified. In the present study, we found that in NK-cell lymphoma lines (n = 10) and specimens of primary lymphoma (n = 10), levels of miR-21 and miR-155 expression were inversely related and were significantly greater than those found in normal natural killer (CD3(-)CD56(+)) cells (n = 8). To determine the functions of these microRNAs in lymphomagenesis, we examined the effects of antisense oligonucleotides (ASOs) targeting miR-21 (ASO-21) and/or miR-155 (ASO-155) in NK-cell lymphoma lines overexpressing one or both of these miRNAs. Conversely, cells showing little endogenous expression of miR-21 or miR-155 were transduced by the use of lentiviral vectors, leading to their overexpression. Reducing expression of miR-21 or miR-155 led to up-regulation of phosphatase and tensin homologue (PTEN), programmed cell death 4 (PDCD4), or Src homology-2 domain-containing inositol 5-phosphatase 1 (SHIP1). ASO-21- and ASO-155-treated cell lines all showed down-regulation of phosphorylated AKT(ser473). Moreover, transduction with either miR-21 or miR-155 led to down-regulation of PTEN and PDCD4 or SHIP1 with up-regulation of phosphorylated AKT(ser473). Collectively, these results provide important new insight into the pathogenesis of NK-cell lymphoma/leukemia and suggest targeting miR-21 and/or miR-155 may represent a useful approach to treating NK-cell lymphoma/leukemia.

Efficacy of atorvastatin for the treatment of nonalcoholic steatohepatitis with dyslipidemia.

Nonalcoholic steatohepatitis (NASH) is the hepatic manifestation of the metabolic syndrome. Currently, there is no established therapy for NASH. The aim of the present study was to evaluate the efficacy of atorvastatin in the treatment of NASH associated with hyperlipidemia. This prospective study included 31 patients with biopsy-proven NASH with hyperlipidemia. Body mass index, serum lipids, liver function tests, fibrosis markers, and adipocytokines (adiponectin, leptin, tumor necrosis factor-alpha) were measured periodically during an open-label study of atorvastatin (10 mg daily) for 24 months. Standard weight-loss counseling was continued during the treatment period. Oral glucose tolerance test and liver density assessed by computerized tomography were performed before and after treatment. Follow-up liver biopsy was performed in 17 patients. All 31 patients had high cholesterol levels at baseline, and 20 also presented high triglyceride levels. The body mass index and serum glucose levels did not change during the treatment. After treatment, 23 patients (74.2%) presented normal transaminase levels. Adiponectin levels were significantly increased, and the levels of tumor necrosis factor-alpha were significantly decreased. However, leptin levels were not changed significantly. The concentration of long-chain fatty acids was decreased; and significant decreases were observed in C18:2,n-6 (linoleic acid, -21%) and C20:4,n-6 (arachidonic acid, -22%). Liver steatosis and nonalcoholic fatty liver disease activity score were significantly improved, whereas 4 patients had increased fibrosis stage. The NASH-related metabolic parameters improved with therapy, including fibrosis in some patients. However, 4 of 17 patients had progression of fibrosis over the 2-year period, with 3 of them progressing to stage 3. It is unclear whether this divergent response represents sampling error, heterogeneity in the population, or untreated postprandial hyperglyceridemia. Controlled trials are needed to further investigate and resolve this.

Analysis of mutations in the urate transporter 1 (URAT1) gene of Japanese patients with hypouricemia in northern Japan and review of the literature.

BACKGROUND: Renal hypouricemia is an autosomal recessive disorder resulting from inactivating mutations in the urate transporter 1 (URAT1) encoded by SLC22A12. To date, 10 mutations have been identified and W258X in the URAT1 gene is the predominant cause in middle to southwestern Japan. However, it is still unclear whether there is a regional specific distribution of mutations in northern Japan. In this study, we analyzed mutations in the URAT1 gene of five Japanese patients with renal hypouricemia in northern Japan. METHODS: Peripheral blood mononuclear cells were isolated from patients with hypouricemia and healthy control subjects. A mutation analysis of the URAT1 gene was performed completely by direct automated sequencing of polymerase chain reaction-amplified DNA products. RESULTS: We identified two mutations. These mutations [c.269G>A (R90H) and c.774G>A (W258X)] have been reported in Japanese patients. Two of five patients were homozygotes (W258X), two carried single heterozygous mutations (W258X), and the remaining one was a compound heterozygote (R90H and W258X). CONCLUSIONS: Our study suggests that there is no regional different distribution of the URAT1 genetic mutations in Japanese with renal hypouricemia.

Prevalence of Helicobacter pylori infection, endoscopic gastric findings and dyspeptic symptoms among a young Japanese population born in the 1970s.

BACKGROUND: With the prevalence of Helicobacter pylori (H. pylori) infection rapidly decreasing in Japan, endoscopic findings and dyspeptic symptoms need to be re-evaluated. METHODS: In a health check-up program, endoscopy was performed on 530 young Japanese subjects (371 men and 159 women) born in the 1970s. Helicobacter pylori infection was evaluated using serology and a rapid urease test. Endoscopic gastritis was classified according to the Sydney classification system, in addition to nodular gastritis. Dyspeptic symptoms were also recorded before endoscopy. RESULTS: Of the 530 subjects, 87 (16.4%) were H. pylori positive. Of the 443 H. pylori-negative subjects, 349 (78.8%) were considered to have endoscopically normal gastric mucosa. However, of the 87 H. pylori-positive subjects, only 19 (21.8%) tested normal (P < 0.001). The prevalence of several types of gastritis was significantly higher in H. pylori-positive subjects compared with H. pylori-negative subjects: atrophic gastritis (37.9% vs 1.1%, P < 0.001), flat erosive gastritis (29.9% vs 7.2%, P < 0.001), rugal hyperplastic gastritis (12.6% vs 0.0%, P < 0.001), and nodular gastritis (13.8% vs 0.0%, P < 0.001). Other types of gastritis were not related to H. pylori status. The prevalence of subjects with dyspeptic symptoms was significantly higher in H. pylori-positive subjects compared with H. pylori-negative ones (28.7% vs 6.5%, P < 0.001). CONCLUSION: It is suggested that in consideration of its recent low prevalence and the slow increase in its infection, the prevalence of H. pylori-related gastritis will gradually decrease in Japan. Further studies will be required to ascertain if there is a need for H. pylori eradication in this young population.

Up-regulation of TRAIL mRNA expression in peripheral blood mononuclear cells from patients with minimal-change nephrotic syndrome.

BACKGROUND: Minimal-change nephrotic syndrome (MCNS) is considered to be associated with T-cell dysfunction and with the abnormal secretion of putative glomerular permeability factors; however, the nature of such factors remains elusive. METHODS: To identify up-regulated genes during the nephrosis phase, we undertook serial analyses of gene expression (SAGE) in peripheral blood mononuclear cells (PBMC) from a patient with MCNS sampled during the nephrosis and remission phases. To confirm the SAGE results, we performed quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) analyses. We also measured the serum levels of the identified gene product in nephrosis and remission samples from 29 MCNS patients, 57 patients with nephrotic syndrome due to other types of glomerular diseases and 30 healthy individuals. RESULTS: Using more than 20,000 SAGE tags, we identified 15 functionally known genes that were up-regulated (>or=4-fold) in PBMC from the MCNS patient during the nephrosis phase. For further examination, we selected two genes encoding secretory proteins, namely tumour necrosis factor-related apoptosis-inducing ligand (TRAIL) and tissue inhibitor of metalloprotease 1. Real-time RT-PCR analysis confirmed a higher expression of TRAIL mRNA in PBMC during nephrosis than during remission in eight MCNS patients. The expression pattern of TRAIL mRNA, however, was variable among four patients with membranous nephropathy. There was no significant increase of serum levels of a soluble form of TRAIL in MCNS patients during the nephrosis phase. CONCLUSIONS: These results suggest that the intracellular TRAIL mRNA expression in PBMC is up-regulated in MCNS patients during the nephrosis phase. This change may represent either an epiphenomenon or it may provide a potential explanation for the altered T-cell function in MCNS.