110 research outputs found

    Level of protein kinase C activity correlates directly with resistance to adriamycin in murine fibrosarcoma cells

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    AbstractIn this report, we demonstrate a direct correlation between protein kinase C (PKC) activity and adriamycin (ADR) resistance in mouse fibrosarcoma cells. PKC activity was measured in four murine UV-2237M fibrosarcoma cell lines that differed in the degrees to which they expressed resistance to ADR, which is an inhibitor of PKC. A comparison of the four cell lines revealed a positive correlation between the level of PKC activity and resistance to ADR. Incubation of the cells with the PKC inhibitor H-7 produced a partial reversal of ADR resistance. Taken together, these results suggest a role for PKC in the mechanism of ADR resistance

    The molecular biology of lung cancer brain metastasis : an overview of current comprehensions and future perspectives

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    Brain metastases occur in 20-40% of patients with advanced malignancies and lung cancer is one of the most common causes of brain metastases. The occurrence of brain metastases is associated with poor prognosis and high morbidity in patients with advanced lung cancer, even after intensive multimodal therapy. Progress in treating brain metastases has been hampered by a lack of model systems, a lack of human tissue samples, and the exclusion of brain metastatic patients from many clinical trials. While the biology of brain metastasis is still poorly understood, it is encouraging to see more efforts are beginning to be directed toward the study of brain metastasis. During the multi-step process of metastasis, functional significance of gene expressions, changes in brain vasculature, abnormal secretion of soluble factors and activation of autocrine/paracrine signaling are considered to contribute to the brain metastasis development. A better understanding of the mechanism of this disease will help us to identify the appropriate therapeutic strategies, which leads to circumvent brain metastases. Recent findings on the biology of lung cancer brain metastases and translational leads identified by molecular studies are discussed in this review

    ヒト ハイガン サイボウ ニヨル ガンセイ キョウスイ ケイセイ ニオケル VEGF Vascular Endothelial Growth Factor ノ イギ

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    The purpose of this study was to determine the molecular mechanisms that regulate the pathogenesis of malignant pleural effusion (PE) associated with advanced stage human non-small cell lung cancer. Intravenous injection of human PC14PE6 (adenocarcinoma) or H226 (squamous cell carcinoma) cells into nude mice yielded numerous lung lesions. PC14 PE6 lung lesions invaded the pleura and produced PE containing a high level of vascular endothelial growth factor (VEGF)/vascular permeability factor (VPF), resulting in vascular hyperpermeability in the thoracic cavity. Lung lesions produced by H226 cells were confined to the lung parenchyma and did not induce PE. The expression of VEGF/VPF mRNA and protein by the cell lines directly correlated with PE formation. Transfection of H226 cells with either sense-VEGF 165 or sense-VEGF 121 genes did not increase cell invasion into the pleura nor induce formation of PE. However, the injection of the VEGF/ VPF-transfected H226 cells into the pleural space resulted in induction of vascular hyperpermeability and PE, indicating that the production of malignant PE requires tumor cells to invade the pleura and express high levels of VEGF/VPF. Therefore, targeting these steps may control malignant PE in lung cancer patients. PTK787, an inhibitor of VEGF/VPF receptor tyrosine kinase phosphorylation, does not affect the in vitro proliferation of PC14PE6 cells. Oral feeding with PTK787 significantly reduced the formation of PE, but not the number of lung lesions of PC14PE6 cells. Furthermore, treatment with PTK787 significantly suppressed vascular hyperpermeability of PE-bearing mice, suggesting that PTK787 reduced PE formation mainly by inhibition of vascular permeability. Therefore, the VEGF/VPF receptor tyrosine kinase inhibitor PTK787 could be useful clinically for the control of malignant PE in lung cancer patients

    Antivascular therapy of human follicular thyroid cancer experimental bone metastasis by blockade of Epidermal Growth Factor Receptor and Vascular Growth Factor Receptor phosphorylation

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    Patients suffering from bone metastases of Follicular Thyroid Carcinoma (FTC) have a poor prognosis because of the lack of effective treatment strategies. The overexpression of Epidermal Growth Factor Receptor (EGFR) associated with increased vascularity has been implicated in the pathogenesis of FTC and subsequent bone metastases. We hypothesized that inhibiting the phosphorylation of the EGFR and Vascular Endothelial Growth Factor Receptor (VEGFR) by AEE788, a dual tyrosine kinase inhibitor of EGFR and VEGFR, in combination with paclitaxel would inhibit experimental FTC bone lesions and preserve bone structure. We tested this hypothesis using the human WRO FTC cell line. In culture, AEE788 inhibited the EGF-mediated phosphorylation of EGFR, VEGFR2, mitogen-activated protein kinase and Akt in culture. AEE788, alone and in combination with paclitaxel, inhibited cell growth and induced apoptosis. When WRO cells were injected into the tibia of nude mice, tumor and endothelial cells within the lesions expressed phosphorylated EGFR, VEGFR, Akt and mitogen-activated protein kinase that were inhibited by the oral administration of AEE788. Therapy consisting of orally given AEE788 and i.p. injected paclitaxel induced a high level of apoptosis in tumor-associated endothelial cells and tumor cells with the inhibition of tumor growth in the bone and the preservation of bone structure. Collectively, these data show that blocking the phosphorylation of EGFR and VEGFR with AEE788 combined with paclitaxel can significantly inhibit experimental human FTC in the bone of nude mice

    Hematogenous Metastasis of Ovarian Cancer: Rethinking Mode of Spread

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    SummaryOvarian cancer has a clear predilection for metastasis to the omentum, but the underlying mechanisms involved in ovarian cancer spread are not well understood. Here, we used a parabiosis model that demonstrates preferential hematogenous metastasis of ovarian cancer to the omentum. Our studies revealed that the ErbB3-neuregulin 1 (NRG1) axis is a dominant pathway responsible for hematogenous omental metastasis. Elevated levels of ErbB3 in ovarian cancer cells and NRG1 in the omentum allowed for tumor cell localization and growth in the omentum. Depletion of ErbB3 in ovarian cancer impaired omental metastasis. Our results highlight hematogenous metastasis as an important mode of ovarian cancer metastasis. These findings have implications for designing alternative strategies aimed at preventing and treating ovarian cancer metastasis

    In Support of a Patient-Driven Initiative and Petition to Lower the High Price of Cancer Drugs

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    Comment in Lowering the High Cost of Cancer Drugs--III. [Mayo Clin Proc. 2016] Lowering the High Cost of Cancer Drugs--I. [Mayo Clin Proc. 2016] Lowering the High Cost of Cancer Drugs--IV. [Mayo Clin Proc. 2016] In Reply--Lowering the High Cost of Cancer Drugs. [Mayo Clin Proc. 2016] US oncologists call for government regulation to curb drug price rises. [BMJ. 2015
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