ZD6474, an inhibitor of vascular endothelial growth factor receptor tyrosine kinase, inhibits growth of experimental lung metastasis and production of malignant pleural effusions in a non-small cell lung cancer model.

ZD6474 is a novel, orally active inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase, with some additional activity against epidermal growth factor receptor (EGFR) tyrosine kinase. The purpose of this study was to determine the potential of ZD6474 in the control of established experimental lung metastasis and pleural effusions produced by human non-small cell lung cancer (NSCLC) cells. PC14PE6 (adenocarcinoma) and H226 (squamous cell carcinoma) cells express high levels of EGFR and only PC14PE6 cells overexpress VEGF. Neither ZD6474 nor the EGFR tyrosine kinase inhibitor gefitinib inhibit proliferation of PC14PE6 or H226 cells in vitro. Both PC14PE6 and H226 cells inoculated intravenously into nude mice induced multiple lung nodules after 5-7 weeks. In addition, PC14PE6 cells produced bloody pleural effusions. Daily oral treatment with ZD6474 did not reduce the number of lung nodules produced by PC14PE6 or H226 cells, but did reduce the lung weight and the size of lung nodules. ZD6474 also inhibited the production of pleural effusions by PC14PE6 cells. Histological analyses of lung lesions revealed that ZD6474 treatment inhibited activation of VEGFR-2 and reduced tumor vascularization and tumor cell proliferation. Therapeutic effects of ZD6474 were considered likely to be due to inhibition of VEGFR-2 tyrosine kinase because gefitinib was inactive in this model. These results indicate that ZD6474, an inhibitor of VEGFR-2, may be useful in controlling the growth of established lung metastasis and pleural effusions by NSCLC.

Current status and perspective of angiogenesis and antivascular therapeutic strategy: non-small cell lung cancer.

Lung cancer is the leading cause of cancer death worldwide, and most patients die of metastatic disease. Angiogenesis, namely, neovascularization from preexisting vasculature, is necessary for tumor growth in both primary and distant organs to supply oxygen and nutrition. Angiogenesis consists of sprouting and nonsprouting (the enlargement, splitting, and fusion of preexisting vessels) processes, and both can occur concurrently. The growth of non-small cell lung cancer (NSCLC), which accounts for more than 80% of all lung cancers, is usually dependent on angiogenesis, which is regulated by complex mechanisms in the presence of various angiogenesis-related molecules. Vascular endothelial growth factor (VEGF), also known as vascular permeability factor (VPF), is one of the most potent angiogenic molecules, while also regulating both angiogenesis and vascular permeability and hence promoting tumor progression and the development of malignant pleural effusions in NSCLC. Recent clinical trials showed that the anti-VEGF antibody bevacizumab, combined with standard first-line chemotherapy, provided a statistically and clinically significant survival advantage with tolerable toxicity. In addition, the combined use of the anti-VEGF antibody with an inhibitor of epidermal growth factor receptor (EGFR) has also shown favorable antitumor efficiency. These successes proved the validity of an antivasculature strategy for NSCLC. Furthermore, a large number of antivasculature agents have been shown to be effective against multiple targets. The efficiency of these compounds is currently being investigated in clinical trials for NSCLC.

Novel orthotopic implantation model of human malignant pleural mesothelioma (EHMES-10 cells) highly expressing vascular endothelial growth factor and its receptor.

Malignant pleural mesothelioma (MPM) is closely related to exposure to asbestos, and a rapid increase in the number of MPM patients in Japan is estimated in the years 2010-2050. The purpose of the present study was to establish a clinically relevant animal model that shows human patient-like progression of MPM. Here, we demonstrate that a human MPM cell line (EHMES-10) inoculated orthotopically (thoracic cavity) into severe combined immunodeficiency (SCID) mice produces highly vascularized thoracic tumors with pleural dissemination and bloody pleural effusions by 5 weeks, suggesting a patient-like progression of this cell line after orthotopic inoculation. EHMES-10 cells overexpressed vascular endothelial growth factor (VEGF), a molecule responsible for malignant effusions, and its receptor. Treatment with cisplatin, but not gemcitabine, significantly inhibited the production of pleural effusions, but it was not effective for thoracic tumors, consistent with chemotherapy refractory characteristics of MPM in patients. Our patient-like orthotopic model using EHMES-10 cells overexpressing VEGF and its receptor may be useful for examining the molecular pathogenesis of MPM and may contribute to the development of novel treatment strategies for MPM.

Antitumor vascular strategy for controlling experimental metastatic spread of human small-cell lung cancer cells with ZD6474 in natural killer cell-depleted severe combined immunodeficient mice.

BACKGROUND: Small-cell lung cancer is often characterized by rapid growth and metastatic spread. Because tumor growth and metastasis are angiogenesis dependent, there is great interest in therapeutic strategies that aim to inhibit tumor angiogenesis. METHODS: The effect of ZD6474, an orally available inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2) and epidermal growth factor tyrosine kinases, was studied in experimental multiple-organ metastasis models with human small-cell lung cancer cell lines (SBC-3 or SBC-5) in natural killer cell-depleted severe combined immunodeficient mice. RESULTS: Intravenously inoculated SBC-5 cells produced experimental metastases in the liver, lung, and bone whereas SBC-3 cells produced the metastases in the liver, systemic lymph nodes, and kidneys. Daily oral treatment with ZD6474 (50 mg/kg), started on day 14 (after the establishment of micrometastases), significantly reduced the frequency of large (>3 mm) metastatic colonies (in the liver and lymph nodes) and osteolytic bone lesions. ZD6474 treatment did not significantly reduce the frequency of small (<2-3 mm) metastatic lesions found in the lung (SBC-5) or kidney (SBC-3), consistent with an antiangiogenic mechanism of action. Immunohistochemical analysis of SBC-5 metastatic deposits in the liver showed that ZD6474 treatment inhibited VEGFR-2 activation and induced apoptosis of tumor-associated endothelial cells, resulting in decreasing tumor microvessel density. ZD6474 treatment was also associated with a decrease in tumor cell proliferation and an increase in tumor cell apoptosis. The antitumor effects of ZD6474 were considered likely to be due to inhibition of VEGFR-2 tyrosine kinase because gefitinib, a small-molecule inhibitor of epidermal growth factor receptor tyrosine kinase, was inactive in these models. CONCLUSIONS: These results suggest that ZD6474 may be of potential therapeutic value in inhibiting the growth of metastatic small-cell lung cancer in humans. Phase II trials with ZD6474 are currently ongoing in a range of solid tumors.

SRC tyrosine kinase inhibitor, m475271, suppresses subcutaneous growth and production of lung metastasis via inhibition of proliferation, invasion, and vascularization of human lung adenocarcinoma cells.

Src, a proto-oncogene, has been strongly implicated in the growth, progression and metastasis of a number of human cancers. Its role in lung cancer is, however, still unknown. In the present study, we assessed the expression of Src in three different human lung adenocarcinoma cell lines (PC-9, PC14PE6, A549), and explored the effect of a novel Src kinase inhibitor, M475271, on the behavior of the cell lines. The three cell lines expressed various levels of auto-phosphorylated Src. While M475271 reduced Src-phosphorylation and invasiveness of all three cell lines, it inhibited the proliferation of PC-9 and A549 cells with highly phosphorylated Src, but not PC14PE6 cells. We further examined the effect of M475271 on subcutaneous tumors and lung metastasis caused by PC-9 and/or A549 cells in NK-cell depleted SCID mice. Daily oral treatment with M475271 inhibited the growth of subcutaneous tumors with PC-9 and A549 cells via inhibition of tumor cells proliferation, VEGF production and/or vascularization in the mice in a dose-dependent manner. In the metastasis model with A549 cells, the lung weight in the M475271 (50 mg/kg)-treated group was less than that of the control group, despite no difference in the number of metastatic nodules. Our results suggest that inhibition of tyrosine kinase Src by M475271 could reduce the growth, invasion and VEGF-mediated neovascularization of lung adenocarcinoma cells, resulting in inhibition of growth of subcutaneous tumors and lung metastasis. Therefore, a novel Src tyrosine kinase inhibitor, M475271, might be helpful for controlling the progression of human lung adenocarcinoma.

A case of sarcoidosis accompanying squamous cell carcinoma in the mandibular gingiva.

A 51-year-old man with a history of gingival cancer two years previously was referred to our hospital for further examination of chest abnormal shadow. Bilateral hilar and mediastinal lymphadenopathy, diffuse small nodular opacities and pleural nodules were observed in chest high resolution CT. Serum angiotensin converting enzyme and lysozyme were elevated. Transbronchial lung biopsy specimens demonstrated non-caseous granuloma. CD4-positive lymphocytes were increased in broncho-alveolar lavage (CD4/CD8 ratio 5.47). The patient was diagnosed as having sarcoidosis. Radiological findings were improved and serum angiotensin converting enzyme level was decreased to within the normal range by corticosteroid therapy (prednisolone 30 mg/day). This is the first report of sarcoidosis accompanying the gingival cancer.

Sensitization of tumor-associated endothelial cell apoptosis by the novel vascular-targeting agent ZD6126 in combination with cisplatin.

PURPOSE: ZD6126 is a novel vascular-targeting agent that selectively disrupts the tubulin cytoskeleton of endothelial cells. In the immature vessels characteristic of tumor vasculature, this leads to endothelial cell contraction, blood vessel congestion, and, consequently, tumor cell death. ZD6126 has been shown to delay tumor growth in a range of xenograft models. The antitumor effect of ZD6126 can be increased in combination with cisplatin or radiation therapy, although the precise mechanism of this enhancement has not been demonstrated. ZD6126 treatment has also been shown to inhibit lung metastasis, and the present study has explored the potential to increase the antimetastatic effect of ZD6126 by combining with cisplatin, and the underlining mechanism has been investigated. EXPERIMENTAL DESIGN: Human lung adenocarcinoma PC14PE6 cells were injected into the tail vein of nude mice. Five weeks after injection animals were treated with ZD6126 (200 mg/kg i.p.), cisplatin (6 mg/kg i.v.), or a combination of the two agents. The animals were sacrificed 24 hours later, and the extent of lung metastases and the presence of apoptotic cells were assessed. RESULTS: Histologic analysis revealed that the ZD6126/cisplatin combination resulted in a 2 to 4-fold increase in the total number of tumor-associated apoptotic cells compared with either treatment alone. ZD6126 alone induced apoptosis of tumor-associated endothelial cells in tumors, and the extent of apoptosis was increased 2-fold in combination with cisplatin. The lung weight was significantly reduced, and the number of metastatic nodules significantly was lower in the combined treatment group than in the control group. CONCLUSIONS: These data suggest that the antimetastatic effect of the vascular-targeting agent ZD6126 can be increased by use in combination with cisplatin, which increases the incidence of endothelial cell apoptosis.

Inhaled steroid therapy and hospitalization for bronchial asthma: trend in Tokushima University Hospital.

With the recognition that airway inflammation is present even in patients with mild bronchial asthma, therapy with inhaled corticosteroids is now indicated in various stages of patients. In the present article, we retrospectively examined the prescriptions for inhaled corticosteroids and other drugs for the treatment of outpatients with bronchial asthma at Tokushima University Hospital. We also analyzed asthma control in these patients, in terms of the incidence of emergency consultations and hospitalizations due to asthma exacerbations. To analyze the recent trend, the patients observed from 1998 to 2000 (recent years) were included, and for control purpose, those in 1990 and 1991 (earlier years) were also included. The percentage of patients treated with inhaled corticosteroids remarkably increased in recent years (mean; 81.3%) compared to earlier years (mean; 23.5%). In contrast, the usage of oral corticosteroids, oral xanthine derivatives, beta-adrenergic receptor agonists and anti-allergic agents tended to decrease in the 10 years period. After the introduction in 1995, considerable patients up to 25% have been treated with anti-leukotrienes. Emergency consultations decreased in recent years (mean; 0.18/patient/year) compared to earlier years (mean; 0.79/patient/year). Emergency hospitalizations also decreased in recent years (mean; 0.043/patient/year) compared to earlier years (mean; 0.23/patient/ year). In the present study, spread of inhaled corticosteroid therapy and decline in incidence of emergency consultation and hospitalization were simultaneously observed at Tokushima University Hospital, and the former has, at least in part, a contribution to the latter.

Activity of a new vascular targeting agent, ZD6126, in pulmonary metastases by human lung adenocarcinoma in nude mice.

ZD6126 (ANG453) is a novel vascular targeting agent that selectively disrupts the cytoskeleton of endothelial cells in tumor. In mouse s.c. xenograft models, ZD6126 was found to induce selective occlusion of tumor blood vessels, cessation of tumor blood flow, and death of tumor cells because of the starvation of oxygen and nutrition. Here, we investigated whether ZD6126 inhibited the metastatic formation of human non-small cell lung cancer cells. PC14PE6 (adenocarcinoma) and H226 (squamous cell carcinoma) cells were injected into the tail vein of nude mice, and lung metastases were estimated. ZD6126 treatment involved either a single dose on 24 h before killing or daily doses from day 14 until the end of the experiment. Single treatment with i.p. injection of 200 mg/kg ZD6126 caused bleeding and necrotic changes in the tumor by 24 h. Histological analysis revealed that apoptotic tumor cells were markedly increased in the ZD6126-treated group. Moreover, ZD6126 induced the apoptosis of CD31-positive vascular endothelial cells in tumors but not in the normal lung parenchyma. When mice were treated daily with 100 mg/kg ZD6126 from day 14 until the end of the experiment, the lung weight was significantly less in the ZD6126-treated group than that of the control group, despite no difference in the number of metastatic nodules. These data suggest that ZD6126 could demonstrate its antitumor activity against both already established and early phase of lung cancer metastasis by causing the selective apoptosis of tumor endothelial cells and destruction of the tumor vasculature.