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We herein report a unique case of type B2 thymoma-associated myasthenia gravis which was ameliorated by immunosuppressive therapy in combination with chemotherapy. However, the patient subsequently developed pure red cell aplasia and marked lymphocytosis after additional chemotherapy aimed at improvement of thymoma. While a separate immunosuppressive regimen was effective for anemia, lymphocytosis was exacerbated. The biopsied thymoma specimen contained CD4+, CD8+, and CD4+/CD8+ T cells, some of which were CD3−, suggesting immature thymocytes. In contrast, majority of the peripheral lymphocytes were polyclonal CD3+/CD8+/T cell receptor (TCR)αβ+ T cells. The CD4/CD8 ratio in the present patient might be affected by immunosuppressive agents, resulting in CD8+ T cell expansion associated with pure red cell aplasia. Although several cases of thymoma accompanied by peripheral T cell lymphocytosis were reported, marked CD8+ T cell proliferation is extremely rare.

We report a unique case of mediastinal grey zone lymphoma that was considered to originate from CD20 + CD30 + Hodgkin cell–like cells associated with a multilocular thymic cyst that had been completely removed 4 years previously. In the formerly resected thymus, irregular-shaped cysts were observed, and large CD20 + CD30 + Hodgkin cell–like cells proliferated in close association with the proliferating thymic epithelial cells. This case suggests the important role of thymic columnar epithelial cells in the proliferation of thymic B cells and the tumorigenesis of mediastinal grey zone lymphoma. Also, it suggests that mediastinal grey zone lymphoma can proliferate slowly in the very early stage.

Carbon monoxide (CO) levels in expired gas are higher in patients with bronchial asthma than in healthy individuals. Heme oxygenase-1 (HO-1) is a rate-limiting enzyme that catalyzes the degradation of heme to yield biliverdin, CO and free iron. Thus, HO-1 is implicated in the pathogenesis of bronchial asthma. However, whether HO-1 expression and activity in lung tissue are related to allergic airway inflammation remains unclear. We investigated whether expression of HO-1 is related to allergic airway inflammation in lungs and whether HO-1 could influence airway hyperresponsiveness and eosinophilia in mice sensitized to ovalbumin (OVA).C57BL/6 mice immunized with OVA were challenged thrice with an aerosol of OVA every second day for 8 days. HO-1-positive cells were identified by immunostaining in lung tissue, and zinc protoporphyrin (Zn-PP), a competitive inhibitor of HO-1, was administered intraperitoneally to OVA-immunized C57BL/6 mice on day 23 (day before inhalation of OVA) and immediately before inhalation on the subsequent 4 days (total five doses). Mice were analyzed for effects of HO-1 on AHR, inflammatory cell infiltration and cytokine levels in lung tissue. Ethical approval was obtained from the concerned institutional review board.Number of HO-1-positive cells increased in the subepithelium of the bronchi after OVA challenge, and HO-1 localized to alveolar macrophages. Zn-PP clearly inhibited AHR, pulmonary eosinophilia and IL-5 and IL-13 expression in the lung tissue.Expression of HO-1 is induced in lung tissue during attacks of allergic bronchial asthma, and its activity likely amplifies and prolongs allergic airway inflammation.

The newly synthesized naftopidil analogue HUHS1015 reduced cell viability in malignant pleural mesothelioma cell lines MSTO-211H, NCI-H28, NCI-H2052, and NCI-H2452, with the potential greater than that for the anticancer drugs paclitaxel or cisplatin at concentrations higher than 30 μM. HUHS1015 induced both necrosis and apoptosis of MSTO-211H and NCI-H2052 cells. HUHS1015 upregulated expression of mRNAs for Puma, Hrk, and Noxa in MSTO-211H and NCI-H2052 cells, suggesting HUHS1015-induced mitochondrial apoptosis. HUHS1015 clearly suppressed tumor growth in mice inoculated with NCI-H2052 cells. Taken together, the results of the present study indicate that HUHS1015 could be developed as an effective anticancer drug for treatment of malignant pleural mesothelioma.

Malignant mesothelioma (MM) is a highly aggressive tumor associated with asbestos exposure. The identification of a marker specific for MM may be of considerable value for the early detection of this tumor and may be used in particular to screen groups with a history of asbestos exposure. The aim of this study was to evaluate serum soluble mesothelin-related peptide (SMRP) levels as a diagnostic marker for MM and investigate whether its diagnostic value is enhanced by combination with other biomarkers. Serum SMRP levels were measured using a quantitative enzyme-linked immunosorbent assay in 96 patients with MM, 55 patients with lung cancer and 39 individuals with a history of asbestos exposure. Receiver operating characteristic curves were constructed for performance evaluation. Stepwise logistic regression analysis was used to select marker combinations (MCs). Serum SMRP levels in patients with MM were significantly higher compared to those in the other groups (P

Background/Aims: Accumulating evidence has suggested that free fatty acids (FFAs) interact with protein kinases and protein phosphatases. The present study examined the effect of FFAs on protein phosphatases and Akt. Methods: Activities of protein phosphatase 1 (PP1), protein phosphatase 2A (PP2A), and protein tyrosine phosphatase 1B (PTP1B) were assayed under the cell-free conditions. Phosphorylation of Akt was monitored in MSTO-211H human malignant pleural mesothelioma cells without and with knocking-down phosphatidylinositol 3 kinase (PI3K) or 3-phosphoinositide-dependent protein kinase-1 (PDK1). Results: In the cell-free assay, unsaturated FFAs (uFFAs) such as oleic, linoleic and linolenic acid and saturated FFAs (sFFAs) such as stearic, palmitic, myristic, and behenic acid markedly reduced PTP1B activity, with the potential for uFFAs greater than that for sFFAs. All the investigated sFFAs inhibited PP2A activity, but otherwise no inhibition was obtained with uFFAs. Both uFFAs and sFFAs had no effect on PP1 activity. Oleic acid phosphorylated Akt both on Thr308 and Ser473, while stearic acid phosphorylated Akt on Thr308 alone. The effects of oleic and stearic acid on Akt phosphorylation were abrogated by the PI3K inhibitor wortmannin or the PDK1 inhibitor BX912 and also by knocking-down PI3K or PDK1. Conclusion: The results of the present study indicate that uFFAs and sFFAs could activate Akt through a pathway along a PI3K/PDK1/Akt axis in association with PTP1B inhibition.

Here, we report a rare case of double-hit lymphoma, demonstrating t(6;14;18)(p25;q32;q21), suggesting two independent dual-translocations, c-MYC/BCL-2 and IRF4/BCL-2. The present case had a rare abnormal chromosome, t(6;14;18)(p25;q32;q21), independently, in addition to known dual-hit chromosomal abnormalities, t(14;18)(q32;q21) and t(8;22)(q24;q11.2). Lymph node was characterized by a follicular and diffuse growth pattern with variously sized neoplastic follicles. The intrafollicular area was composed of centrocytes with a few centroblasts and the interfollicular area was occupied by uniformly spread medium- to large-sized lymphocytes. CD23 immunostaining demonstrated a disrupted follicular dendritic cell meshwork. The intrafollicular tumor cells had a germinal center phenotype with the expression of surface IgM, CD10, Bcl-2, Bcl-6, and MUM1/IRF4. However, the interfollicular larger cells showed plasmacytic differentiation with diminished CD20, Bcl-2, Bcl-6, and positive intracytoplasmic IgM, and co-expression of MUM1/IRF4 and CD138 with increased Ki-67-positive cells (> 90%). MUM1/IRF4 has been found to induce c-MYC expression, and in turn, MYC transactivates MUM1/IRF4, creating a positive autoregulatory feedback loop. On the other hand, MUM1/IRF4 functions as a tumor suppressor in c-MYC-induced B-cell leukemia. The present rare case arouses interest in view of the possible "dual" activation of both c-MYC and MUM1/IRF4 through two independent dual-translocations, c-MYC/BCL-2 and IRF4/BCL-2.

Nodal marginal zone B cell lymphoma is a rare type of malignant lymphoma and appears to be heterogeneous. Here we report a 60-year-old woman with stage I splenic type of nodal marginal zone B cell lymphoma with prominent follicular colonization. She was treated only by radiation therapy, and remained free of disease on examination for 4 years. The lymph node cells showed an abnormal chromosome of deletion 13, although neither bone marrow cells nor peripheral blood cells demonstrated the same abnormal chromosome. This type of chromosomal abnormality has not been previously reported and may be related to good prognosis in the present case.

Background/Aims: Sphingosine regulates cellular differentiation, cell growth, and apoptosis. The present study aimed at understanding sphingosine-regulated mesothelioma cell proliferation. Methods: Human malignant mesothelioma cells such as NCI-H28, NCI-H2052, NCI-H2452, and MSTO-211H cells were cultured. The siRNA to silence the protein kinase C (PKC)-δ-targeted gene was constructed and transfected into cells. MTT assay, cell cycle analysis using a flow cytometry, and cell-free PKC-δ assay were carried out. Results: For all the cell types sphingosine inhibited cell growth in a concentration (1-100 µM)-dependent manner. The sphingosine effect was not prevented by rottlerin, an inhibitor of protein kinase C-δ (PKC-δ); conversely, rottlerin further enhanced the sphingosine effect or rottlerin suppressed mesothelioma cell growth without sphingosine. In the cell-free PKC assay, sphingosine attenuated PKC-δ activity. Knocking-down PKC-δ induced cell cycle arrest at the G0/G1 phase and inhibited cell growth. Conclusion: The results of the present study show that sphingosine suppressed mesothelioma cell proliferation by inhibiting PKC-δ, to induce cell cycle arrest at the G0/G1 phase.

Background/Aims: The present study investigated adenosine-induced apoptosis in human malignant pleural mesothelioma cells. Methods: MTT assay, TUNEL staining, flow cytometry using propidium iodide and annexin V-FITC, real-time RT-PCR, Western blotting, and assay of caspase-3, -8, and -9 activities were carried out using malignant pleural mesothelioma cell lines such as NCI-H28, NCI-H2052, NCI-H2452, and MSTO-211H cells, and p53 or A3 adenosine receptor was knocked-down by transfecting each siRNA into cells. Results: Adenosine induced apoptosis in all the malignant pleural mesothelioma cells used here, independently of caspase activation. The adenosine effect was prevented by the adenosine transporter inhibitor dipyridamole, the adenosine kinase inhibitor ABT-702, or the A3 adenosine receptor inhibitor MRS1191. Adenosine upregulated expression of the p53 mRNA and protein, that is abolished by ABT-702, but not by knocking-down A3 adenosine receptor. Adenosine-induced apoptosis in NCI-H28 cells was significantly inhibited by knocking-down p53 and in part by knocking-down A3 adenosine receptor. Conclusion: The results of the present study show that AMP converted from intracellularly transported adenosine upregulates p53 expression to induce caspase-independent apoptosis in malignant pleural mesothelioma cells and that A3 adenosine receptor also participates partially in the apoptosis by the different mechanism.

Malignant pleural mesothelioma (MPM) is an aggressive malignant tumour of mesothelial origin associated with asbestos exposure. Because MPM has limited response to conventional chemotherapy and radiotherapy, the prognosis is very poor. Several researchers have reported that cytokines such as interleukin (IL)-6 play an important role in the growth of MPM. Previously, it was reported that all-trans-retinoic acid (ATRA) inhibited the production and function of IL-6 and transforming growth factor (TGF)-beta1 in experiments using lung fibroblasts. We investigated whether ATRA had an inhibitory effect on the cell growth of MPM, the origin of which was mesenchymal cells similar to lung fibroblasts, using a subcutaneous xenograft mouse model. We estimated the tumour growth and performed quantitative measurements of IL-6, TGF-beta1 and platelet-derived growth factor (PDGF) receptor (PDGFR)-beta mRNA levels both of cultured MPM cells and cells grown in mice with or without the administration of ATRA. ATRA significantly inhibited MPM tumour growth. In vitro studies disclosed that the administration of ATRA reduced 1) mRNA levels of TGF-beta1, TGF-beta1 receptors and PDGFR-beta, and 2) TGF-beta1-dependent proliferation and PDGF-BB-dependent migration of MPM cells. These data may provide a rationale to explore the clinical use of ATRA for the treatment of MPM.

We report two elderly male patients with hemophagocytic syndrome (HPS) associated with systemic lupus erythematosus (SLE). They were admitted to the hospital because of general malaise. At admission, they showed fever of unknown origin and hematological abnormalities without typical symptoms for SLE such as arthralgia or malar rash. Chest X-rays, computed tomography and cardiac sonogram demonstrated unilateral pleural and pericardial effusions. Bone marrow aspiration revealed hypocellular marrow with increased macrophages phagocytosing blood cells in the both cases. One patient had positive reactivity for direct Coombs's test and high level of platelet-associated antibody, whose symptoms were ameliorated only by 20 mg per day of prednisolone. The other patient, however, progressive worsened and died regardless of intensive treatment containing methyl-prednisolone pulse therapy. Late-onset lupus (LO-SLE) patients tend to have a more insidious onset of disease, and less frequently show typical symptoms of early-onset SLE such as malar rash. So it seems to be important that clinicians make a fast diagnosis and proper treatment for LO-SLE and associated HPS by careful observation for the latent symptoms and laboratory findings.

Background/aims Liver fibrosis with any aetiology, induced by the transdifferentiation and proliferation of hepatic stellate cells (HSCs) to produce collagen, is characterized by progressive worsening in liver function, leading to a high incidence of death. We have recently reported that all-trans-retinoic acid (ATRA) suppresses the transdifferentiation and proliferation of lung fibroblasts and prevents radiation- or bleomycin-induced lung fibrosis. Methods We examined the impact of ATRA on carbon tetrachloride (CCl(4))-induced liver fibrosis. We performed histological examinations and quantitative measurements of transforming growth factor (TGF)-beta1 and interleukin (IL)-6 in CCl(4)-treated mouse liver tissues with or without the administration of ATRA, and investigated the effect of ATRA on the production of the cytokines in quiescent and activated HSCs. Results CCl(4)-induced liver fibrosis was attenuated in histology by intraperitoneal administration of ATRA, and the overall survival rate at 12 weeks was 26.5% without ATRA (n=25), whereas it was 75.0% (n=24) in the treatment group (P=0.0187). In vitro studies disclosed that the administration of ATRA reduced (i) the production of TGF-beta1, IL-6 and collagen from HSCs, (ii) TGF-beta-dependent transdifferentiation of the cells and IL-6-dependent cell proliferation and (iii) the activities of nuclear factor-kappaB p65 and p38mitogen-activated protein kinase, which stimulate the production of TGF-beta1 and IL-6, which could be the mechanism underlying the preventive effect of ATRA on liver fibrosis. Conclusions Our findings indicate that ATRA ameliorates liver fibrosis. As the oral administration of the drug results in good compliance, ATRA could be a novel approach in the treatment of liver fibrosis.

We report a very rare case of a 45-year-old Japanese male patient with hairy cell leukemia-Japanese variant (HCL-JV) expressing CD27. The patient showed a high number of abnormal peripheral lymphocytes, thrombocytopenia, and severe splenomegaly but no lymphadenopathy. Histology of the resected spleen showed small-sized lymphoma cells diffusely infiltrating the red pulp without follicle formation. By immunohistochemistry, lymphoma cells were negative for CD3, CD5, CD8, CD10, CD34, cyclin-D1, and annexin A1 but positive for CD20 and BCL2. BRAF V600E mutation was not observed. Bone marrow aspirate showed preserved normal hematopoietic cells with invasion of lymphoma cells in an interstitial pattern without obvious nodules. The cells had abundant pale cytoplasm and round nuclei with inconspicuous nucleoli. After natural drying, the cells had unevenly distributed microvilli. Flow cytometric analysis demonstrated positivity for CD11a, CD11c, CD19, CD20, CD22, CD27, surface IgG, and λ but not for CD2, CD3, CD4, CD5, CD7, CD8, CD10, CD21, CD23, CD25, CD30, CD34, CD38, CD43, CD56, CD57, CD103, IgD, IgM, and κ. Monoclonal expansion of B cells was confirmed by an immunoglobulin heavy chain (IgH) rearrangement band as demonstrated by Southern blot hybridization. The lymphoma cells had unevenly distributed long, large, and broad-based microvilli, which resembled splenic diffuse red pulp small B cell lymphoma (SDRPL) cells. CD27 expression is extremely rare in HCL-JV, but the young age of the patient and high peripheral WBC counts were similar to HCL-JV, which suggests, in this case, an intermediate disease between SDRPL and HCL-JV.

Malignant mesothelioma is an aggressive tumor arising from mesothelial cells of serous membranes, and forms spheroid-like cell aggregates in pleural and peritoneal effusions. We examined the levels of anoikis, apoptosis induced by the detachment of cells from the extracellur matrix, in suspension culture in the human mesothelioma cell line NCI-H2052. NCI-H2052 cells were adherent in conventional monolayer cultures, but were found to form spheroids in suspension cultures using dishes with ultra-low cell binding capacity. NCI-H2052 cells proliferated in both cultures, but the proliferation rate was markedly lower in suspension cultures than in monolayer cultures. In addition, NCI-H2052 cells in suspension cultures showed little apoptosis, suggesting that the suspension culture induces anoikis resistance. Western blot analysis revealed that suspension cultures induced activation of Src family kinases (SFK) after spheroid formation. Dasatinib, an inhibitor of multi-tyrosine kinases including SFK, abolished anoikis resistance in suspension cultures, indicating that SFK activated by spheroid formation are responsible for anoikis resistance. Cisplatin induced apoptosis in NCI-H2052 cells, but the apoptotic rate was significantly lower in suspension cultures than in monolayer cultures, suggesting that spheroid formation is involved in cisplatin resistance. Furthermore, a combination of dasatinib and cisplatin induced apoptosis more significantly than either alone in suspension cultures. These results suggest that spheroid formation induces resistance to anoikis and to cisplatin through SFK activation and that dasatinib facilitates cisplatin-induced apoptosis in human mesothelioma cells.

Malignant pleural mesothelioma (MPM) is associated with a history of heavy, long-term exposure to asbestos. However, MPM may also be associated with simian virus 40 (SV40), a polyomavirus. The association between SV40 and MPM remains unclear. The present study was conducted in order to investigate the proportion of SV40 presence in the histological specimens of Vietnamese patients with MPM. Histological specimens were obtained from 45 patients (19 men and 26 women) with MPM at the Pham Ngoc Thach Hospital in Ho Chi Minh City, Vietnam. The specimens were processed and examined in order to detect the presence of the SV40 large T antigen (SV40 Tag) expression using immunohistochemistry. Of the 45 patients, 23 (51%) were epithelioid, 7 (16%) were biphasic, 6 (13%) were sarcomatoid, 4 (9%) were desmoplastic, 4 (9%) were well-differentiated papillary and 1 (2%) was the anaplastic subtype. In total, 9/45 patients (20%) demonstrated SV40 Tag expression. The proportion of patients that demonstrated SV40 Tag expression was not significantly different between the epithelioid subtype and the other subtypes (22 vs. 18%; P=1.000) or between the patients with stage IV disease and other stages (20 vs. 20%; P=1.000). The median survival time was not significantly different between the patients with or without SV40 Tag expression (196 vs. 236 days, P=0.8949). In summary, a 5th of the Vietnamese patients with MPM were associated with infection with SV40. SV40 may be a potential cause of MPM in Vietnam and this potential association requires additional studies.

We report a patient who had a 4-year history of adult-onset Still's disease (AOSD) and showed a prominent increase in large granular lymphocytes (LGL) when she developed severe Pseudomonas conjunctivitis due to Pseudomonas aeruginosa, skin eruptions, liver damage, and abnormal findings in coagulation studies, without any evidence of active viral activation, hemophagocytosis, or malignancies. The increased LGL cells were CD3(+)CD8(+), and disappeared promptly after the administration of antibiotics combined with prednisolone, with subsequent stabilization of her general condition.

We report a rare primary splenic diffuse large B-cell lymphoma demonstrating CD5(+) and CD23(+) with very low CD20 expression. The only lesion was detected in the spleen, which was extremely enlarged with multiple large white-colored nodules. The lesion was characterized by a diffuse growth pattern of medium- to large-sized lymphoma cells with abundant cytoplasm. Immunohistochemical and flow cytometric study demonstrated that the lymphoma cells were negative for CD2, CD3, CD4, CD8, CD10, CD56, CD138, ALK-1, λ-light chain, and cyclin-D1, and positive for CD5, CD19, CD23, CD25, CD38, CD43, CD79a, IgM, IgD, κ-light chain, BCL2, BCL6, BOB. 1, Oct-2, Pax5, and MUM-1. CD20 was very weakly positive immunohistochemically, and negative by flow cytometric analysis. These findings resembled Richter syndrome, although chronic lymphocytic leukemia was not preexisting. Extremely poor outcome might be supposed because the effect of rituximab might be quite limited since CD20 was very weakly positive, in addition to an inferior prognosis of both CD20(-) and CD5(+) diffuse large B-cell lymphoma. Careful management is thus necessary.

Background/Aims: Our earlier studies suggested crosstalk between IRS/PI3 kinase/PDK1/Akt/Rac1/ROCK and (Shc2/Grb2/SOS)/Ras/Raf/MEK/ERK pathways downstream PDGF-ββ receptor responsible for chemotaxis and proliferation of malignant mesothelioma cells. The present study was conducted to obtain evidence for this. Methods: To assess activation of Akt, MEK, and ERK, Western blotting was carried out on MSTO-211H malignant mesothelioma cells using antibodies against phospho-Thr308-Akt, phopho-Ser473-Akt, Akt, phospho-MEK, MEK, phopho-ERK1/2, and ERK1/2. To knock-down Akt, PI3 kinase, PDK1, and Rac1, siRNAs silencing each-targeted gene were constructed and transfected into cells. To monitor Rac1 activity, FRET monitoring was carried out on living and fixed cells. Results: ERK was activated under the basal conditions in MSTO-211H cells, and the activation was prevented by inhibitors for PI3 kinase, PDK1, Akt, and Rac1 or by knocking-down PI3 kinase, PDK1, Akt, and Rac1. Akt was also activated under the basal conditions, and the activation was suppressed by a MEK inhibitor and an ERK1/2 inhibitor. In the FRET analysis, Rac1 was activated under the basal conditions, and the activation was inhibited by a MEK inhibitor and an ERK1/2 inhibitor. Conclusion: The results of the present study show that ERK could be activated by PI3 kinase, PDK1, Akt, and Rac1 and that alternatively, Akt and Rac1 could be activated by MEK and ERK in MSTO-211H cells.

Here we demonstrate a unique case of CD20-negative low-grade B cell lymphoma showing immunophenotypic and genotypic features resembling multiple myeloma. The female patient had no abnormal masses, splenomegaly, swelled lymph nodes, or bone lesions. Although serum levels of IgG, IgA, and IgM were decreased without M protein, κ-type Bence-Jones protein was observed. In bone marrow, monotonous proliferation of small to medium-sized lymphoid cells was observed without classical myeloma cells, the same histological findings as lymphoplasmacytic lymphoma. The cells were CD38+, CD138+, CD43+, CD44+, CD3-, CD4-, CD5-, CD7-, CD8-, CD10-, CD11b-, CD19-, CD20-, CD21-, CD23-, CD24-, CD25-, CD27-, CD40-, CD45-, and CD56-. Surface or cytoplasmic IgM, κ, or λ were all negative. Chromosomal analysis demonstrated t(11;14)(q13;q32). The present case may belong to a new entity of low-grade B cell lymphoma with the same histological findings as lymphoplasmacytic lymphoma, mainly proliferated in bone marrow whose immunophenotype and genotype are similar to plasma cell myeloma.

Background/Aims: A3 adenosine receptor mediates apoptosis in cancer cells via diverse signaling pathways. The present study examined A3 adenosine receptor-mediated apoptosis in Lu-65 cells, a human giant cell lung carcinoma cell line. Methods: MTT assay, TUNEL staining, real-time RT-PCR, Western blotting, and assay of caspase-3, -8, and -9 activities were carried out in Lu-65 cells, and A3 adenosine receptor or p53 was knocked-down by transfecting each siRNA into cells. Results: Extracellular adenosine induces Lu-65 cell apoptosis in a concentration (0.01-10 mM)-dependent manner, and the effect was inhibited by the A3 adenosine receptor inhibitor MRS1191 or by knocking-down A3 adenosine receptor or p53. Like adenosine, the A3 adenosine receptor agonist 2-Cl-IB-MECA also induced Lu-65 cell apoptosis. Adenosine upregulated expression of p53 and Noxa mRNAs and activated caspase-3 and -9, but not caspase-8. Those adenosine effects were still inhibited by knocking-down A3 adenosine receptor or p53. Conclusion: The results of the present study show that adenosine upregulates p53 expression via A3 adenosine receptor, to promote p53-dependent Noxa gene transcription, causing activation of caspase-9 and the effector caspase-3 to induce Lu-65 cell apoptosis.

Background Malignant pleural mesothelioma (MPM) is an aggressive malignant tumor of mesothelial origin associated with asbestos exposure. MPM has a limited response to conventional chemotherapy and radiotherapy, so early diagnosis of MPM is very important. This study investigated the pleural effusion mesothelin levels in patients with MPM and compared them to those of a population with a non-malignant pleuritis or lung cancer involving malignant pleural effusion. Methods The pleural effusion mesothelin concentrations were measured in 45 MPM patients and 53 non-MPM individuals (24 individuals with non-malignant pleural effusions and 29 individuals with lung cancer involving malignant pleural effusion). Results This study demonstrated that patients with MPM had significantly higher pleural effusion mesothelin levels than a population with non-malignant pleuritis or lung cancer involving malignant pleural effusion. The difference in overall survival between the groups with pleural effusion mesothelin levels lower and higher than the assumed cut-off of 10 nM was significant. Conclusions The data suggest that the pleural effusion mesothelin concentration could be useful as an aid for the diagnosis of MPM.

Malignant mesothelioma is an aggressive tumor of serosal surfaces that is closely associated with asbestos exposure which induces oxidative stress. Heme oxygenase (HO)-1, a rate-limiting enzyme of heme degradation, plays a protective role against oxidative stress. The HO-1 gene promoter carries (GT)n repeats whose number is inversely related to transcriptional activity of the HO-1 gene.To investigate the relationship between the length polymorphism of (GT)n repeats and mesothelioma susceptibility, we analyzed the HO-1 promoter in 44 asbestos-exposed subjects without mesothelioma and 78 asbestos-exposed subjects with mesothelioma using PCR-based genotyping.The number of repeats ranged from 16 to 38, with two peaks at 23 and 30 repeats. Polymorphisms of (GT)n repeats were grouped into two classes of alleles, short (S) (24) and long (L) (≥24), and three genotypes: L/L, L/S, and S/S. The proportions of allele frequencies in class L as well as genotypic frequencies of L allele carriers (L/L and L/S) were significantly higher in the asbestos-exposed subjects with mesothelioma than in those without mesothelioma.The findings of this study suggest that long (GT)n repeats in the HO-1 gene promoter are associated with a higher risk of malignant mesothelioma in the Japanese population.

In some instances, because of the lack of mass formation and the absence of prominent lymph node enlargement, diagnosis of lymphoma-associated hemophagocytic syndrome (LAHS) is difficult, which results in the development of progressive disease with unfavorable prognosis. Therefore, in the diagnosis of secondary hemophagocytic syndrome (HPS), markers for underlying malignant lymphoma are required. We reviewed 110 Japanese patients, including 57 LAHS cases and 53 benign disease-associated HPS cases, and demonstrated that the values of the serum sIL-2R level and sIL-2R/ferritin ratio in LAHS patients were both statistically higher than those of patients with benign disease-associated HPS. Most LAHS patients showed high values of both indices. The positive predictive value of patients showing high values of both indices for LAHS was 95.6%. On the other hand, the predictive value of patients showing low values of both indices for benign disease-associated HPS was 92.1%. We propose serum sIL-2R/ferritin ratio as a novel useful marker for predicting underlying malignant lymphoma in HPS patients.

Malignant mesothelioma is an aggressive tumor of serosal surfaces, which is refractory to current treatment options. Arsenic trioxide (As2O3) is used clinically to treat acute promyelocytic leukemia, and also to inhibit proliferation of several solid tumors including hepatoma, esophageal, and gastric cancer in vitro. Here we found that As2O3 inhibited cell viability of a mesothelioma cell line, NCI-H2052. As2O3 induced apoptosis of NCI-H2052 cells, which was accompanied by activation of c-Jun NH2-terminal kinase (JNK)1/2, extracellular signal-regulated kinase (ERK)1/2, and caspase-3. zVAD-fmk, a broad-spectrum caspase inhibitor, inhibited As2O3-induced apoptosis and activation of caspase-3, but not that of JNK1/2 and ERK1/2. Small interfering RNAs (siRNAs) targeting JNK1/2 suppressed As2O3-induced caspase-3 activation and apoptosis, indicating that JNK1/2 regulate As2O3-induced apoptosis though caspase cascade. Furthermore, JNK1 siRNA abrogated As2O3-induced JNK2 phosphorylation and JNK2 siRNA abrogated As2O3-induced JNK1 phosphorylation, suggesting that JNK1 and JNK2 interact with each other. Moreover, JNK1 siRNA, but not JNK2 siRNA, abrogated As2O3-induced ERK1/2 phosphorylation. JNK2 siRNA together with PD98059, a specific MAPK/ERK kinase inhibitor, suppressed As2O3-induced apoptosis more significantly than JNK2 siRNA alone. These results indicated that As2O3 induces apoptosis of NCI-H2052 cells mainly through JNK1/2 activation, and that ERK1/2 is involved in As2O3-induced apoptosis when JNK1/2 are inactivated.

The mucin-type transmembrane glycoprotein podoplanin (also known as T1alpha, gp38 or Aggrus) is well established as one of the lymphatic-specific markers. Podoplanin was also reported to be associated with tumor-induced platelet aggregation and tumor metastasis. Here, we generated a novel monoclonal antibody (clone; 7B10) that specifically recognized human podoplanin, as assessed by enzyme-linked immunosorbent assay, Western blot analyses, immunohistochemistry and flow cytometry. 7B10 stained not only lymphatic vessels but also type I alveolar cells in the lung, podocytes in the kidney and myoepithelial cells in the breast. In addition, podoplanin expression was analyzed by immunostaining on tissue microarrays that included 12 different cancer types using 7B10. Consequently, we found that podoplanin was expressed by cancer cells derived from esophagus, lung, liver, colon and breast, as well as lymphatic endothelial cells. These findings suggest a potential role of podoplanin in tumor progression in diverse types of human cancers.

Although high-dose thoracic radiotherapy is an effective strategy for some malignancies including lung cancers and malignant lymphomas, it often causes complications of radiation fibrosis. To study the mechanism initiating tissue fibrosis, we investigated irradiation-induced cytokine production from human lung fibroblastic cells and found that IL-6 production was stimulated by irradiation. IL-6 is an autocrine growth factor for human myeloma cells, and retinoic acid is reported to inhibit their growth. Thus we evaluated the effect of all- trans retinoic acid (ATRA) on cell proliferation of lung fibroblasts along with the cytokine/receptor system. Irradiation-dependent stimulation of IL-6 production was correlated with increased NF-κB activity, and ATRA reduced this effect. Irradiation also increased the levels of mRNA for IL-6R and gp130, which were blocked by coexisting ATRA. Furthermore, IL-6 stimulated cell proliferation in dose-dependent manner but was overcome by pharmacological concentration of ATRA. These effects of ATRA were inhibited by rottlerin, which suggests ATRA abolished irradiation-induced stimulation through a PKCδ-dependent pathway. Finally, we demonstrated that IL-6 transcripts in the lung were upregulated at 2 mo after irradiation, and the effect was inhibited by the intraperitoneal administration of ATRA. ATRA is expected to have an advantage for radiotherapy in its antitumor effects, as reported previously, and to prevent radiotherapy-induced pulmonary injury.

7582 Background: Serum mesothelin is the best available blood test for diagnosing MPM, but provides a poor sensitivity (J Clin Oncol 2012). We previously showed that two blood tests, a test for cir...

SRPX2 (Sushi repeat-containing protein, X-linked 2) has recently emerged as a multifunctional protein that is involved in seizure disorders, angiogenesis and cellular adhesion. Here, we analyzed this protein biochemically. SRPX2 protein was secreted with a highly post-translational modification. Chondroitinase ABC treatment completely decreased the molecular mass of purified SRPX2 protein to its predicted size, whereas heparitinase, keratanase and hyaluroinidase did not. Secreted SRPX2 protein was also detected using an anti-chondroitin sulfate antibody. These results indicate that SRPX2 is a novel chondroitin sulfate proteoglycan (CSPG). Furthermore, a binding assay revealed that hepatocyte growth factor dose-dependently binds to SRPX2 protein, and a ligand–glycosaminoglycans interaction was speculated to be likely in proteoglycans. Regarding its molecular architecture, SRPX2 has sushi repeat modules similar to four other CSPGs/lecticans; however, the molecular architecture of SRPX2 seems to be quite different from that of the lecticans. Taken together, we found that SRPX2 is a novel CSPG that is overexpressed in gastrointestinal cancer cells. Our findings provide key glycobiological insight into SRPX2 in cancer cells and demonstrate that SRPX2 is a new member of the cancer-related proteoglycan family.

Background Malignant pleural mesothelioma (MPM) is an aggressive malignant tumor of mesothelial origin associated with asbestos exposure. MPM has a limited response to conventional chemotherapy and radiotherapy, so the early diagnosis of MPM is very important. This study investigated the pleural effusion mesothelin levels in patients with MPM and compared them with those of a population with a non-malignant pleuritis or lung cancer involving malignant pleural effusion. Methods The pleural effusion mesothelin concentrations were measured in 45 MPM patients and 53 non-MPM individuals (24 individuals with non-malignant pleural effusions and 29 individuals with lung cancer involving malignant pleural effusion). Results This study demonstrated that patients with MPM had significantly higher pleural effusion mesothelin levels than a population with non-malignant pleuritis or lung cancer involving malignant pleural effusion. The difference in overall survival between the groups with pleural effusion mesothelin levels lower and higher than the assumed cutoff of 10 nM was significant. Conclusions The data suggest that the pleural effusion mesothelin concentration could be useful as an aid for the diagnosis of MPM.

Summary Pulmonary fibrosis is characterized by progressive worsening of pulmonary function leading to a high incidence of death. Currently, however, there has been little progress in therapeutic strategies for pulmonary fibrosis. There have been several reports on cytokines being associated with lung fibrosis, including interleukin (IL)-6 and transforming growth factor (TGF)-β1. We reported recently that two substances (ATRA and thalidomide) have preventive effects on pulmonary fibrosis by inhibiting IL-6-dependent proliferation and TGF-β1-dependent transdifferentiation of lung fibroblasts. Rheumatoid arthritis is a chronic autoimmune disorder, and its pathogenesis is also characterized by an association with several cytokines. It has been reported that calpain, a calcium-dependent intracellular cysteine protease, plays an important role in the progression of rheumatoid arthritis. In this study, we examined the preventive effect of Calpeptin, a calpain inhibitor, on bleomycin-induced pulmonary fibrosis. We performed histological examinations and quantitative measurements of IL-6, TGF-β1, collagen type Iα1 and angiopoietin-1 in bleomycin-treated mouse lung tissues with or without the administration of Calpeptin. Calpeptin histologically ameliorated bleomycin-induced pulmonary fibrosis in mice. Calpeptin decreased the expression of IL-6, TGF-β1, angiopoietin-1 and collagen type Iα1 mRNA in mouse lung tissues. In vitro studies disclosed that Calpeptin reduced (i) production of IL-6, TGF-β1, angiopoietin-1 and collagen synthesis from lung fibroblasts; and (ii) both IL-6-dependent proliferation and angiopoietin-1-dependent migration of the cells, which could be the mechanism underlying the preventive effect of Calpeptin on pulmonary fibrosis. These data suggest the clinical use of Calpeptin for the prevention of pulmonary fibrosis.

e21165 Background: Histone deacetylase (HDAC) modulates gene expression through the deacetylation of lysine residues on histone proteins and acts transcriptional repressors of genes. HDAC is curren...