Chiharu Tabata

Clinical Significance of Serum Vascular Endothelial Growth Factor in Malignant Pleural Mesothelioma

Introduction: 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 diagnosing MPM early is very important. Vascular endothelial growth factor (VEGF) is an autocrine growth factor for MPM. Here, we investigated the serum levels of VEGF in patients with MPM in comparison with a population that had been exposed to asbestos without developing MPM. Methods: Serum concentrations of VEGF were measured in 51 patients with MPM and 42 individuals with benign asbestos-related diseases (asbestosis or pleural plaques) or who were healthy despite asbestos exposure. Results: We demonstrated that patients with MPM had significantly higher serum levels of VEGF than a population who had been exposed to asbestos but had not developed MPM, and the patients with advanced stage MPM showed higher levels of VEGF than the early stage patients with MPM. The difference in overall survival between the groups with VEGF serum levels lower and higher than the assumed cutoff of 460 pg/ml was significant. Conclusions: Our data suggest that the VEGF serum concentration could be a useful marker for screening MPM among asbestos-exposed individuals and as a prognostic factor.

Arsenic trioxide induces apoptosis through JNK and ERK in human mesothelioma cells

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. J. Cell. Physiol. 226: 762–768, 2011.

Significant increase in circulating tumour cells in pulmonary venous blood during surgical manipulation in patients with primary lung cancer

OBJECTIVES Circulating tumour cells (CTCs) are tumour cells shed from a primary tumour and circulate in the peripheral blood after passing through the drainage vein. In previous studies, we showed that high numbers of CTCs were detected in the drainage pulmonary venous blood of most patients with resectable primary lung cancer, whereas only low numbers of CTCs were detected in the peripheral blood of some patients. Accordingly, this prospective study was conducted to assess changes in CTCs in the drainage pulmonary vein (PV) during lung cancer surgery. METHODS A total of 30 consecutive peripheral-type primary lung cancer patients who underwent lobectomy (or right upper and middle bilobectomy) through open thoracotomy were included. For each patient, 2.5 ml of blood was sampled from the lobar PV of the primary tumour site before and after surgical manipulation for lobectomy. The CTCs were evaluated quantitatively with the CellSearch® system. RESULTS Before surgical manipulation, CTCs were detected in PV blood in the majority of patients (22 of 30, 73.3%), although CTCs were detected in peripheral blood in only two patients (6.7%). The median number of CTCs in the PV (pvCTC-count) before surgical manipulation was 4.0 cells/2.5 ml, and there was no significant correlation between pvPV-count and any clinicopathological characteristic, including tumour size, progression and histological type. After surgical manipulation, at the time of completion of the lobectomy, the pvCTC-count significantly increased (median, 60.0 cells/2.5 ml; P = 0.001). The increase in pvCTC-count was significantly associated with microscopic lymphatic tumour invasion (ly); pvCTC-count significantly increased in ly-positive patients (pvCTC-count before and after surgical manipulation, 4.0 and 90.5 cells/2.5 ml, respectively; P = 0.006), but not in ly-negative patients (3.5 and 7.0 cells/2.5 ml, respectively; P = 0.153). The increase in pvCTC-count was not significantly associated with any other clinicopathological factor or with any surgical procedure, including the sequence of vessel interruption. CONCLUSIONS We documented a significant increase in CTC count in drainage PV blood after surgical manipulation, especially in tumours with lymphatic invasion. We are awaiting survival data at 5 year follow-up examination, which may provide clinical significance of the pvCTC-count.

Serum HMGB1 as a prognostic marker for malignant pleural mesothelioma

BackgroundMalignant pleural mesothelioma (MPM) is an aggressive malignant tumor of mesothelial origin that shows a limited response to conventional chemotherapy and radiotherapy. Therefore, diagnosing MPM early is very important. Some researchers have previously reported that high-mobility group box 1 (HMGB1) was correlated with pulmonary fibrosis. MPM involves the malignant transformation of mesothelial cells, which originate from mesenchymal cells similar to lung fibroblasts. Here, we investigated serum levels of HMGB1 in patients with MPM and compared them with those of a population that had been exposed to asbestos without developing MPM.MethodsHMGB1 production from MPM cell lines was measured using ELISA. Serum HMGB1 levels were also examined in 61 MPM patients and 45 individuals with benign asbestos-related diseases.ResultsHMGB1 concentrations of 2 out of 4 MPM cell lines were higher than that of normal mesothelial cell line, Met-5A. We demonstrated that patients with MPM had significantly higher serum levels of HMGB1 than the population who had been exposed to asbestos but had not developed MPM. The difference in overall survival between groups with serum HMGB1 levels that were lower and higher than assumed cut-off values was significant.ConclusionsOur data suggest that serum HMGB1 concentration is a useful prognostic factor for MPM.

Pleural effusion VEGF levels as a prognostic factor of malignant pleural mesothelioma

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. Vascular endothelial growth factor (VEGF), a potent mitogen for the vascular endothelium, is also known to be an autocrine growth factor for MPM. Here, we investigated the pleural effusion VEGF 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 VEGF concentrations were measured in 46 MPM patients and 45 individuals with non-MPM individuals (25 individuals with non-malignant pleural effusions, and 20 individuals with lung cancer involving malignant pleural effusion). RESULTS We demonstrated that patients with MPM had significantly higher pleural effusion VEGF levels than a population with non-malignant pleuritis or lung cancer involving malignant pleural effusion, and the patients with advanced stage MPM showed higher levels of VEGF than the early stage MPM patients. The difference in overall survival between the groups with pleural effusion VEGF levels lower and higher than the assumed cut-off of 2000pg/ml was significant. CONCLUSIONS Our data suggest that the pleural effusion VEGF concentration could be useful as an aid for the diagnosis of MPM and as a prognostic factor.

All-trans-retinoic acid ameliorates carbon tetrachloride-induced liver fibrosis in mice through modulating cytokine production.

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.

Crosstalk between PI3 Kinase/PDK1/Akt/ Rac1 and Ras/Raf/MEK/ERK Pathways Downstream PDGF Receptor

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.

Clinical significance of pleural effusion mesothelin in malignant pleural mesothelioma.

Abstract 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.

A3 adenosine receptor-mediated p53-dependent apoptosis in Lu-65 human lung cancer cells.

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.

Possible prediction of underlying lymphoma by high sIL-2R/ferritin ratio in hemophagocytic syndrome

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.