Effect of metformin on residual cells after chemotherapy in a human lung adenocarcinoma cell line.

Cancer chemotherapy, including molecular targeted therapy, has major limitations because it does not kill all the cancer cells; the residual cells survive until they acquire chemoresistance. In the present study, the combined effects of metformin and gefitinib were examined in vivo in a mouse xenograft model, inoculated with a human lung adenocarcinoma cell line that possesses an activating epidermal growth factor receptor mutation. The mechanism of the interaction was further elucidated in vitro. Metformin did not suppress the growth of already established tumors, nor did metformin augment tumor shrinkage by gefitinib. However, metformin significantly suppressed the regrowth of the tumor after effective treatment with gefitinib, suggesting the specific effect of metformin on the residual cells. Cytotoxicity of metformin was characterized by the absence of apoptosis induction and unremarkable cell cycle shift in vitro. The residual cell population after treatment with gefitinib was characterized by enriched cells with high expression of CD133 and CD24. Metformin was still effective on this specific cell population. Targeting residual cells after chemotherapy may represent an effective novel strategy for the treatment of cancer. Elucidating the mechanism of metformin cytotoxicity provides insights into future development of anticancer therapeutics.

Antiproliferative action of metformin in human lung cancer cell lines.

The oral antidiabetic agent metformin has anticancer properties, probably via adenosine monophosphate-activated protein kinase activation. In the present study, growth inhibition was assessed by a clonogenic and by a cell survival assay, apoptosis induction was assessed by Hoechst staining and caspase activities and cell cycle alteration after exposure to metformin, and the interaction of metformin with cisplatin in vitro were elucidated in four human lung cancer cell lines representing squamous, adeno-, large cell and small cell carcinoma. Clonogenicity and cell proliferation were inhibited by metformin in all the cell lines examined. This inhibitory effect was not specific to cancer cells because it was also observed in a non-transformed human mesothelial cell line and in mouse fibroblast cell lines. Inhibition of clonogenicity was observed only when the cells were exposed to metformin for a long period, (10 days) and the surviving fraction, obtained after inhibiting proliferation by increasing the dose, reached a plateau at approximately 0.1-0.3, indicating the cytostatic characteristics of metformin. Metformin induced significant apoptosis only in the small cell carcinoma cell line. A tendency of cell cycle accumulation at the G0/G1 phase was observed in all four cell lines. Cisplatin, in a dose-dependent manner, severely antagonized the growth inhibitory effect of metformin, and even reversed the effect in three cell lines but not in the adenocarcinoma cell line. The present data obtained using various histological types of human lung cancer cell lines in vitro illustrate the cytostatic nature of metformin and its cytoprotective properties against cisplatin.

Interaction and cross-resistance of cisplatin and pemetrexed in malignant pleural mesothelioma cell lines.

Although cisplatin and pemetrexed are key drugs in the treatment of malignant pleural mesothelioma, their drug-drug interactions, cross-resistance and resistance mechanisms in malignant pleural mesothelioma are not well understood. In the present study, the interaction of these 2 agents was determined by clonogenic assays followed by isobologram analysis of 4 human malignant pleural mesothelioma cell lines. The cell lines were exposed to the agents using a stepwise dose-escalation method to establish drug-resistant sublines. Thymidylate synthase mRNA expression was evaluated in the drug-resistant sublines. As a consequence, cisplatin and pemetrexed had synergistic effects in 3 cell lines and an additive effect in the fourth cell line. The former 3 cell lines showed similar pemetrexed sensitivity in the parental cells and their cisplatin-resistant sublines, whereas the fourth cell line exhibited cross-resistance. In contrast, cisplatin had diverse effects on pemetrexed-resistant sublines. High thymidylate synthase expression did not correlate with natural pemetrexed resistance. Elevated thymidylate synthase expression correlated with acquired pemetrexed resistance in 2 sublines. In conclusion, cisplatin and pemetrexed showed synergistic activity and no cross-resistance in 3 of the 4 malignant pleural mesothelioma cell lines, suggesting the clinical relevance of their combination in chemotherapy. Thymidylate synthase expression did not necessarily correlate with pemetrexed resistance. The information together with the experimental model presented here would be useful for further investigating therapeutic targets of malignant mesothelioma.

Characterization of sarcoma-like cells derived from endarterectomized tissues from patients with CTEPH and establishment of a mouse model of pulmonary artery intimal sarcoma.

In general, intravascular thrombus formation in the pulmonary arteries is considered to be the most common cause of chronic thromboembolic pulmonary hypertension (CTEPH). The current mainstay of therapy for patients with CTEPH is pulmonary endarterectomy (PEA). Recently, the existence of myofibroblast-like cells in endarterectomized tissues has been demonstrated. At the 2nd passage of these myofibroblast-like cells, a pleomorphic cell type was isolated. Pulmonary intimal sarcoma is a very uncommon neoplastic tumor thought to originate from subendothelial-mesenchymal cells of the pulmonary vascular wall. Because these pleomorphic cells were isolated from the pulmonary vascular beds, it is believed that the analysis of these cells may contribute to the understanding of pulmonary intimal sarcoma. We isolated cells from the endarterectomized tissue from patients with CTEPH and identified one type as sarcoma-like cells (SCLs). The SCLs were characterized as hyperproliferative, anchorage-independent, invasive and serum-independent. Moreover, C.B-17/lcr-scid/scidJcl mice injected subcutaneously with SCLs developed solid, undifferentiated tumors at the site of injection, and those injected intravenously with SCLs via the tail vein developed tumors which grew along the intimal surface of the pulmonary vessels, thus, demonstrating the high tumorigenic potential of these cells. The behavior of SCLs indicated that these cells may have a vascular cell-like potential which can affiliate them with the intimal surface of the pulmonary artery, and which may be shared with pulmonary intimal sarcoma. A further investigation of this mouse model with SCLs may elucidate the mechanism(s) underlying the development of pulmonary intimal sarcoma.

Characterization of myofibroblasts in chronic thromboembolic pulmonary hypertension.

BACKGROUND: It has been generally accepted that chronic thromboembolic pulmonary hypertension (CTEPH) results from pulmonary embolism arising from deep vein thrombosis. An unresolved question regarding the etiology of CTEPH is why pulmonary thromboemboli are stable and resistant to effective anticoagulation. Recently non-resolving pulmonary thromboemboli in CTEPH have been shown to include myofibroblasts. This study investigates the cellular characteristics of myofibroblasts included in the organized thrombotic tissues of CTEPH. METHODS: Organized thrombotic tissues of patients with CTEPH were obtained following pulmonary endarterectomy. We isolated cells from endarterectomized tissue from patients with CTEPH and identified them as endothelial-like cells and myofibroblast-like cells. RESULTS: Myofibroblast-like cells were characterized as hyperproliferative, anchorage-independent, invasive and serum-independent. CONCLUSIONS: Here we report the presence of active myofibroblast-like cells in endarterectomized tissue of CTEPH. We suggest that the formation of myofibroblasts with a high growth potential in the organized thrombotic tissues may be an important event in the pathobiology of this disease.

Endothelial-like cells in chronic thromboembolic pulmonary hypertension: crosstalk with myofibroblast-like cells.

BACKGROUND: Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by intravascular thrombus formation in the pulmonary arteries.Recently, it has been shown that a myofibroblast cell phenotype was predominant within endarterectomized tissues from CTEPH patients. Indeed, our recent study demonstrated the existence of not only myofibroblast-like cells (MFLCs), but also endothelial-like cells (ELCs). Under in vitro conditions, a few transitional cells (co-expressing both endothelial- and SM-cell markers) were observed in the ELC population. We hypothesized that MFLCs in the microenvironment created by the unresolved clot may promote the endothelial-mesenchymal transition and/or induce endothelial cell (EC) dysfunction. METHODS: We isolated cells from these tissues and identified them as MFLCs and ELCs. In order to test whether the MFLCs provide the microenvironment which causes EC alterations, ECs were incubated in serum-free medium conditioned by MFLCs, or were grown in co-culture with the MFLCs. RESULTS: Our experiments demonstrated that MFLCs promoted the commercially available ECs to transit to other mesenchymal phenotypes and/or induced EC dysfunction through inactivation of autophagy, disruption of the mitochondrial reticulum, alteration of the SOD-2 localization, and decreased ROS production. Indeed, ELCs included a few transitional cells, lost the ability to form autophagosomes, and had defective mitochondrial structure/function. Moreover, rapamycin reversed the phenotypic alterations and the gene expression changes in ECs co-cultured with MFLCs, thus suggesting that this agent had beneficial therapeutic effects on ECs in CTEPH tissues. CONCLUSIONS: It is possible that the microenvironment created by the stabilized clot stimulates MFLCs to induce EC alterations.

[A case of pulmonary arteriovenous fistula treated by transcatheter embolization using 320-row multidetector computed tomography].

The patient was a 34-year-old man, who was referred to our hospital because of abnormal shadows in the right lower lung field on a chest radiograph during a medical screening. Chest computed tomography (CT) showed a pulmonary arteriovenous fistula 23 x 17 mm in size in the anterior basal segment of the right lung, together with a single artery and single vein. He had no symptoms and did not have Osler-Weber-Rendu syndrome. Coil embolization was performed in order to decrease the risk of complications associated with right-to-left shunting. Transcatheter embolization using interlocking detachable coils and detachable fibered coils was successfully performed without severe complications. Then, 320-row multidetector CT revealed that the blood flow from the pulmonary artery disappeared just after coil embolization, the blood flow from the pulmonary vein flowed backward, and the fistula was contrasted. The fistula had almost completely disappeared 8 months after embolization. We confirmed that blood flows were interrupted by 320-row CT and pulmonary angiography. 320-row CT was useful for the evaluation of pulmonary arteriovenous fistula and coil embolization.

[Case of thymic carcinoid associated with multiple endocrine neoplasia type I treated effectively with chemotherapy].

A 53-year-old man was referred to our hospital due to a mediastinal mass found during a medical checkup in July 2009. He had a past history of hyperparathyroidism, for which he underwent surgery in 1994, and also had a family history in that his sister had multiple endocrine neoplasia type 1 (MEN1). He was given a diagnosis of MEN I on genetic testing. Chest CT revealed a mediastinal mass 4 cm in maximum dimension, and an atypical carcinoid was diagnosed according to mediastinal biopsy findings. Bone metastasis was detected and he was given cisplatin and etoposide. The tumor decreased in size by 30%, and was evaluated as showing partial response. Although there are some cases of MEN-related thymoma treated by surgery, a case which successfully responded to chemotherapy alone is thought to be extremely rare.

Durable hypogammaglobulinemia associated with thymoma (Good syndrome).

Good syndrome, characterized by hypogammaglobulinemia and acquired immunodeficiency, is a rare condition associated with thymoma. A 67-year-old woman, who 4 months previously had a thymoma resected, presented with generalized hypogammaglobulinemia with a severely decreased B cell population as demonstrated by flow cytometry. She was diagnosed as having bacterial mediastinitis associated with Good syndrome. For the subsequent 6 years, she suffered from repeated serious bacterial infections. As this paraneoplastic syndrome is not resolved by tumor removal, careful management with intensive infection-control using antibiotics and intravenous immunoglobulins is required for the long term. Serum immunoglobulin levels should be evaluated for patients with thymoma and suspected vulnerability to infection.

[Symptomatic splenomegaly in a young Japanese man with sarcoidosis accompanied by spleen, liver, kidney, lung and lymph node lesions].

A 27-year-old man experienced progressive left hypochondralgia. CT with contrast medium enhancement revealed marked splenomegaly, multiple swollen lymph nodes in the mediastinum and abdominal cavity, and multiple nodules in the spleen, liver, kidneys and lungs. Pathological examinations of the lung and liver lesions showed non-caseating granulomatous lesions, and established the diagnosis of sarcoidosis. The symptom and lesions presented by CT regressed dramatically with administration of corticosteroid (30 mg/day oral prednisolone). Symptomatic splenomegaly in a young Japanese man with sarcoidosis seems very rare especially considering that sarcoidosis lesions completely regress spontaneously within a year in 90% patients of young Japanese men with sarcoidosis.

The role of EBUS-TBNA for the diagnosis of sarcoidosis--comparisons with other bronchoscopic diagnostic modalities.

BACKGROUND: The diagnosis of sarcoidosis requires both compatible clinical features and pathologic findings as a means to exclude other differential diagnoses. The utility of endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) for diagnosis of sarcoidosis has been reported, although its indication remains unclear for cases of suspicious sarcoidosis. To clarify the role of EBUS-TBNA for the diagnosis of sarcoidosis, we compared three diagnostic modalities: EBUS-TBNA, transbronchial lung biopsy (TBLB) and bronchoalveolar lavage fluid analysis (BAL). METHODS: Thirty-eight patients with suspicious sarcoidosis who had enlarged hilar and/or mediastinal lymph nodes on chest CT were retrospectively reviewed. Patients with malignancies or prior established diagnosis of sarcoidosis were excluded. BAL was initially performed followed by TBLB and finally EBUS-TBNA at the same setting. Microbacterial examinations were also performed from all samples. RESULTS: Pathological findings compatible with sarcoidosis were obtained in 32 patients. The remaining 6 patients were diagnosed as one case each of chronic eosinophilic pneumonia, atypical mycobacterial infection and tuberculosis, and the remaining three were pathologically indefinite cases. Clinically, 35 patients were diagnosed with sarcoidosis. The diagnostic accuracy of sarcoidosis was significantly better by EBUS-TBNA (91.4%, p<0.001) compared to the other two modalities. According to chest roentgenogram classifications, there were 31 stage I patients and 4 stage II patients. For stage I patients, EBUS-TBNA was significantly better (90.3%, p<0.001), but each modality showed 100% accuracy for stage II patients. CONCLUSION: It is recommended that EBUS-TBNA is added to the conventional diagnostic modalities for patients with suspicious stage I sarcoidosis on chest roentgenogram.

Chronic obstructive pulmonary disease and interstitial lung disease in patients with lung cancer.

BACKGROUND AND OBJECTIVE: Although lung cancer is frequently accompanied by COPD and interstitial lung disease (ILD), the precise coincidence of these diseases with lung cancer is not well understood. The objectives of this study were to determine the prevalence of abnormal CT and spirometric findings suggestive of COPD or ILD in a population of patients with untreated lung cancer, and to estimate the lung cancer risk in this population. METHODS: The study population consisted of 256 patients with untreated lung cancer and 947 subjects participating in a CT screening programme for lung cancer. Semi-quantitative analysis of low attenuation area (LAA), fibrosis and ground glass attenuation (GGA) on CT was performed by scoring. Gender- and age-matched subpopulations, with stratification by smoking status, were compared using the Mantel-Haenszel projection method. RESULTS: Inter-observer consistency was excellent for LAA, but not as good for fibrosis or GGA scores. Pooled odds ratios for lung cancer risk using LAA, fibrosis, GGA scores and reduced FEV(1)/FVC and %VC were 3.63, 5.10, 2.71, 7.17 and 4.73, respectively (P < 0.0001 for all parameters). Multivariate regression analyses confirmed these results. CONCLUSION: Abnormal CT and spirometric parameters suggestive of COPD and ILD were strong risk factors for lung cancer, even after adjusting for gender, age and smoking status.

[Case of metachronous mucosa-associated lymphoid tissue (MALT) lymphoma originated from a distinct B-cell clone].

Although mucosa-associated lymphoid tissue (MALT) lymphoma is classified as an indolent lymphoma, it frequently disseminates and recurs to make the disease difficult to cure. The present case had metachronous lesions in the skin, orbit and pleura, and all of them were diagnosed as derived from the same monoclonal tumor cell. A 65-year-old woman was admitted to our hospital because of a pleural tumor with pleural effusion. Two years before, she had undergone surgical resection for skin erythematous lesion and an ocular adnexa tumor, which were diagnosed as lymphoid hyperplasia by histological examination at that time. On admission, thoracoscopy-guided biopsy of the pleural tumor with local anesthesia established a diagnosis of MALT lymphoma. The rearranged immunoglobulin heavy chain of the skin tumor, ocular adnexa tumor, pleural tumor and lymphocytes in the pleural effusion were analyzed using a polymerase chain reaction (PCR)-based assay. This analysis revealed the metachronous MALT lymphoma originated from a distinct B-cell clone. After rituximub and CHOP therapy, complete remission was obtained. Although MALT lymphoma occurs in a wide variety of body sites, the pleural presentation of MALT lymphoma is very rare. Lifelong observation of all patients treated for MALT lymphoma is required because of the high frequency of dissemination and recurrence.

Tiotropium bromide attenuates respiratory syncytial virus replication in epithelial cells.

BACKGROUND: Respiratory syncytial virus (RSV) infection could be related to airway inflammation as well as exacerbation of chronic obstructive pulmonary disease (COPD). Tiotropium bromide decreases the frequency of exacerbation in patients with COPD; however, the mechanisms of tiotropium bromide to reduce the chances of exacerbation have not been defined. One potential mechanism could be that tiotropium bromide protects against RSV infection in epithelial cells. OBJECTIVE: To examine whether tiotropium bromide affects RSV replication in HEp-2 cells. METHODS: The supernatant titer of RSV was calculated by methylcellulose plaque assay after RSV innoculation. Intracellular RSV and ICAM-1 mRNA were measured by PCR. Syncytium formation was observed by light microscopy. Intracellular RSV fusion protein and RhoA protein were detected by Western blot analysis. Furthermore, RhoA activity, ICAM-1 expression and inflammatory cytokines in cultured supernatant were measured by binding assay, immunofluorescence staining and ELISA, respectively. RESULTS: Tiotropium bromide decreased the supernatant titer of RSV, and it inhibited syncytium formation, RhoA activation and ICAM-1 expression. Moreover, it suppressed the production of IL-6 and IL-8 after RSV infection. CONCLUSIONS: The antiviral effects of tiotropium bromide regarding RSV replication are partly due to inhibition of RhoA activity and ICAM-1 expression. Tiotropium bromide decreases RSV replication and may modulate airway inflammation by reducing the production of inflammatory cytokines.

Impaired spermatogenesis by testicular sarcoidosis.

Testicular involvement by sarcoidosis is a rare condition. A 23-year-old Japanese man had asymptomatic bilateral testicular lesions, which were detected by gallium scintigram, together with lesions located bilaterally in the uvea, lungs and hilar, and mediastinal lymph nodes and unilateral supraclavicular lymph nodes. Semen analysis demonstrated severely impaired spermatogenesis. Treatment with corticosteroid dramatically improved these lesions and restored spermatogenesis. This case report suggests that testicular sarcoidosis may cause male infertility.

Identification of annexin 1 as a novel autoantigen in acute exacerbation of idiopathic pulmonary fibrosis.

Consistent with the hypothesis that pulmonary epithelial apoptosis is the key to the acute exacerbation of idiopathic pulmonary fibrosis (IPF), we conducted serological identification of Ags by recombinant expression cloning (SEREX) analysis using type II alveolar cell carcinoma (A549) cell lines to identify disease-related Abs. In a survey of Abs to the recombinant autoantigens identified by SEREX analysis, five Abs were identified as novel candidates for the acute exacerbation of IPF. Abs to annexin 1 were detected in 47 and 53% of the sera and bronchoalveolar lavage materials from patients with acute exacerbation of IPF. Some identical TCR Vbeta genes were identified in sequential materials obtained at 1-3 mo in all 10 acute exacerbation IPF cases, suggesting that some infiltrating CD4-positive T cells sharing limited epitopes expand by Ag-driven stimulation during disease extension. The CDR3 region of these identical TCR Vbeta genes showed high homology with the N-terminal portion of annexin 1, including in the HLA-DR ligand epitopes predicted by TEPITOPE analysis. By Western blotting analysis and observation of the CD4-positive T cell responses in bronchoalveolar lavage samples, the N-terminal portion of annexin 1 was cleaved and found to induce marked proliferative responses of CD4-positive T cells in three patients. Our study demonstrates that annexin 1 is an autoantigen that raises both Ab production and T cell response in patients with acute exacerbation of IPF, and that the N-terminal portion of annexin 1 plays some role in the pathogenesis of acute exacerbation in IPF patients.

Pulmonary and systemic toxicity of bleomycin on severe combined immune deficiency mice.

Severe combined immune deficiency (SCID) mice were more sensitive to systemic delivery of bleomycin (BLM) than the wild-type strain, and died from esophagitis. Lung injury in the SCID mice by its intratracheal injection, however, was of comparable degree but with less lymphocyte infiltration than that in the wild-type mice. Macrophages and lymphocytes increased transiently in bronchoalveolar lavage fluid of SCID mice, whereas their increase in wild-type was continuous. Unsustainable inflammation in the lung might reduce BLM-induced lung injury in BLM-sensitive SCID mice.

[A case of angiosarcoma of pelvis with pulmonary metastases which responded to paclitaxel].

A 60-year-old man was admitted to our hospital complaining of back pain and bloody sputum. Chest CT scan showed characteristic multiple small nodules with central dense opacity and surrounding faint opacity, suggesting lesions with hemorrhage. Bone scintigram and MRI revealed multiple osteolytic lesions in pelvis and lumbar spine. Biopsy of the bone lesion established a diagnosis of angiosarcoma. Chemotherapy with paclitaxel and palliative radiotherapy for the bone were initiated. Pulmonary metastases dramatically diminished after 4 courses of paclitaxel treatment. After eight weeks, the tumor recurred. Salvage chemotherapy of weekly administration of docetaxel yielded limited effects. The patient died of cancer one year after treatment initiation.

Altered gene expression by cisplatin in a human squamous cell lung carcinoma cell line.

BACKGROUND: Substantial evidence has disclosed that some cytotoxic agents have complex activities in influencing signal transduction pathways in cells. MATERIALS AND METHODS: cDNA microarray analysis was performed after exposing a human squamous cell carcinoma cell line, RERF-LC-AI, to low-dose cisplatin for 5 days. Up-regulated gene expressions were suppressed by small interfering RNA to investigate phenotypic alteration of the cells. RESULTS: Among 30,000 genes screened, 42 genes showed increases or decreases in expression of more than 2-fold with cisplatin treatment. They included genes with functions involved in apoptosis, cell cycle regulation and DNA metabolism/repair. Suppression of the 5 most significantly altered genes by small interfering RNA resulted in partly reduced apoptosis without altering cytotoxicity of cisplatin. CONCLUSION: Besides direct cytotoxic effects on cells, cisplatin may have indirect effects involving drug resistance, and synergistic effects with other agents.