Chien, Jeremy

AbstractPurpose: The aim of the present study was to evaluate the effects of piroxicam, a widely used nonsteroidal anti-inflammatory drug, alone and in combination with cisplatin (CDDP), on cell growth of mesothelioma cells.Experimental Design: Cell proliferation, cell cycle analysis, and microarray technology were done on MSTO-211H and NCI-H2452 cells treated with piroxicam. Moreover, the effects of piroxicam and CDDP on tumor growth and survival of mouse xenograft models of mesothelioma were determined.Results: Piroxicam treatment of MSTO-211H and NCI-H2452 cells resulted in a significant inhibition of proliferation. Cell cycle analysis revealed that there was an increase in the rate of apoptosis in MSTO-211H cells and an increase in the cells accumulating in G2-M in NCI-H2452. Moreover, a marked tumor growth inhibition and an extended survival of mice treated with a combination of piroxicam and CDDP in MSTO-211H cell–induced peritoneal mesotheliomas was observed. Last, GeneChip array analysis of MSTO-211H mesothelioma cell line revealed that piroxicam treatment caused up-regulation of metabolic pathway–associated genes and down-regulation of genes related to RNA processing apparatus. Of note, epidermal growth factor receptor, one of the new biological targets of chemotherapy for mesothelioma, was down-regulated and HtrA1, a serine protease recently shown to be an endogenous mediator of CDDP cytotoxicity, was up-regulated following piroxicam treatment both in vitro and in vivo.Conclusion: These data suggest that piroxicam sensitizes mesothelioma cells to CDDP-induced cytotoxicity by modulating the expression of several target genes. Therefore, piroxicam in combination with CDDP might potentially be useful in the treatment of patients with mesothelioma.

Abstract We previously identified HSulf-1 as a down-regulated gene in several tumor types including ovarian, breast, and hepatocellular carcinomas. Loss of HSulf-1, which selectively removes 6-O-sulfate from heparan sulfate, up-regulates heparin-binding growth factor signaling and confers resistance to chemotherapy-induced apoptosis. Here we report that HSulf-1 expression in MDA-MB-468 breast carcinoma clonal lines leads to reduced proliferation in vitro and reduced tumor burden in athymic nude mice in vivo. Additionally, xenografts derived from HSulf-1–expressing stable clones of carcinoma cells showed reduced vessel density, marked necrosis, and apoptosis, indicative of inhibition of angiogenesis. Consistent with this observation, HSulf-1–expressing clonal lines showed reduced staining with the endothelial marker CD31 in Matrigel plug assay, indicating that HSulf-1 expression inhibits angiogenesis. More importantly, HSulf-1 expression in the xenografts was associated with a reduced ability of vascular endothelial cell heparan sulfate to participate in a complex with fibroblast growth factor 2 (FGF-2) and its receptor tyrosine kinase FGF receptor 1c. In vitro, short hairpin RNA–mediated down-regulation of HSulf-1 in human umbilical vein endothelial cells (HUVEC) resulted in an increased proliferation mediated by heparan sulfate–dependent FGF-2, hepatocyte growth factor, and vascular endothelial growth factor 165 (VEGF165) but not by heparan sulfate–independent VEGF121. HSulf-1 down-regulation also enhanced downstream signaling through the extracellular signal–regulated kinase pathway compared with untreated cells. Consistent with the role of heparan sulfate glycosaminoglycan sulfation in VEGF-mediated signaling, treatment of HUVEC cells with chlorate, which inhibits heparan sulfate glycosaminoglycan sulfation and therefore mimics HSulf-1 overexpression, led to an attenuated VEGF-mediated signaling. Collectively, these observations provide the first evidence of a novel mechanism by which HSulf-1 modulates the function of heparan sulfate binding VEGF165 in proliferation and angiogenesis. (Cancer Res 2006; 66(12): 6025-32)

Abstract ATR (ataxia telangiectasia and Rad3-related) function is necessary for the proper response to commonly used chemotherapeutic agents. Heterozygous truncating mutations in exon 10 of the ATR gene have been described in numerous cancers exhibiting microsatellite instability. We show that truncating mutations of ATR are capable of acting in a dominant-negative manner to abrogate ATR-dependent Chk1 phosphorylation and cell-cycle arrests after DNA damage. In addition, endometrial cell lines harboring ATR mutations are defective for ATR-dependent responses. These findings imply that ATR mutations play an important role in the development and clinical behavior of a subset of microsatellite instability–positive endometrial, colon, and stomach cancers.