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Lee H.W.,Cancer Stem Cell Research Center | Lee H.W.,Samsung | Park Y.M.,Samsung | Lee S.J.,Cancer Stem Cell Research Center | And 15 more authors.
Clinical Cancer Research | Year: 2013

Purpose: Metastatic relapse of primary lung cancer leads to therapeutic resistance and unfavorable clinical prognosis; therefore, identification of key molecules associated with metastatic conversion has significant clinical implications. We previously identified a link between early brain metastasis of lung adenocarcinoma and amplification of the a-smooth muscle actin (ACTA2) gene. The aim of present study was to investigate the prognostic and functional significance of ACTA2 expression in cancer cells for the metastatic potential of lung adenocarcinomas. Experimental Design: ACTA2 expression was analyzed in tumor cells from 263 patients with primary lung adenocarcinomas by immunohistochemistry, and was correlated with clinicopathologic parameters. The expression of ACTA2 in human lung adenocarcinoma cells was modulated with short hairpin RNAs (shRNA) and siRNAs specifically targeting ACTA2. Results: The patients with lung adenocarcinomas with high ACTA2 expression in tumor cells showed significantly enhanced distant metastasis and unfavorable prognosis. ACTA2 downregulation remarkably impaired in vitro migration, invasion, clonogenicity, and transendothelial penetration of lung adenocarcinoma cells without affecting proliferation. Consistent with the in vitro results, depletion of ACTA2 in human lung adenocarcinoma PC14PE6 cells significantly reduced their metastatic potential without altering their tumorigenic potential. Expression of c-MET and FAK in lung adenocarcinoma cells was also reduced by ACTA2-targeting siRNAs and shRNAs, and was accompanied by a loss of mesenchymal characteristics. Conclusions: These findings indicate that ACTA2 regulates c-MET and FAK expression in lung adenocarcinoma cells, which positively and selectively influence metastatic potential. Therefore, ACTA2 could be a promising prognostic biomarker and/or therapeutic target for metastatic lung adenocarcinoma. © 2013 American Association for Cancer Research.


PubMed | Cancer Stem Cell Research Center
Type: Journal Article | Journal: Experimental and therapeutic medicine | Year: 2012

We hypothesized that methotrexate (MTX) normalizes the increased permeability of the blood-tumor barrier and thus reduces the accessibility of rituximab (RTX) to central nervous system (CNS) lymphoma. Here, we evaluated the combinational treatment capability of RTX and MTX using an alternative treatment schedule against CNS lymphoma. We developed a CNS lymphoma animal model that closely mimics the morphological and molecular characteristics of human CNS lymphoma by injecting Raji human Burkitt lymphoma cells into the brains of immune-compromised mice and tested a novel combinational treatment schedule by which penetration of RTX was not influenced by MTX administration. RTX was conjugated with Alexa Fluor 680, and its distribution in the brain was analyzed by in vivo imaging. When MTX treatment was followed by a 3-day post RTX administration, RTX was scarcely distributed in the brain, and there were only modest statistically insignificant therapeutic effects compared with the control mice which received sham injections. In contrast, RTX administration followed by a 3-day post MTX treatment showed significantly increased distribution of RTX and significantly reduced tumor volume in the brain. Collectively, our data demonstrate that RTX can be successfully combined with MTX using an alternative treatment schedule that allows increased distribution of RTX in CNS lymphoma.

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