bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Minimal Active Domain of Endostatin Is a Heparin-Binding Motif that Mediates Inhibition of Tumor Vascularization
Authors: Olsson Anna-Karin , Johansson Irja , Åkerud Helena , Einarsson Barbro , Christofferson Rolf , Sasaki Takako , Timpl Rupert , Claesson-Welsh Lena 
Published: September 2005

Abstract
Endostatin constitutes the COOH-terminal 20,000 Da proteolytic fragment of collagen XVIII and has been shown to possess antiangiogenic and antitumorigenic properties. In the present study, we have investigated the role of the heparin-binding sites in the in vivo mechanism of action of endostatin. The majority of the heparin binding is mediated by arginines 155/158/184/270 in endostatin, but there is also a minor site constituted by arginines 193/194. Using endostatin mutants lacking either of these two sites, we show that inhibition of fibroblast growth factor-2–induced angiogenesis in the chicken chorioallantoic membrane requires both heparin-binding sites. In contrast, inhibition of vascular endothelial growth factor-A–induced chorioallantoic membrane angiogenesis by endostatin was only dependent on the minor heparin-binding site (R193/194). These arginines were also required for endostatin to inhibit fibroblast growth factor-2– and vascular endothelial growth factor-A–induced chemotaxis of primary endothelial cells. Moreover, we show that a synthetic peptide corresponding to amino acids 180–199 of human endostatin (which covers the minor heparin-binding site) inhibits endothelial cell chemotaxis and reduces tumor vascularization in vivo. Substitution of arginine residues 193/194 for alanine attenuates the antiangiogenic effects of the peptide. These data show an essential role for heparin binding in the antiangiogenic action of endostatin.
The Anticancer Drug Ellipticine Forms Covalent DNA Adducts, Mediated by Human Cytochromes P450, through Metabolism to 13-Hydroxyellipticine and EllipticineN2-Oxide
Authors: Stiborová Marie , Sejbal Jan , Bořek-Dohalská Lucie , Aimová Dagmar , Poljaková Jitka , Forsterová Kristina , Rupertová Martina , Wiesner Jiří , Hudeček Jiří , Wiessler Manfred , Frei Eva 
Published: September 2005

AbstractEllipticine is an antineoplastic agent, the mode of action of which is considered to be based on DNA intercalation and inhibition of topoisomerase II. We found that ellipticine also forms the cytochrome P450 (CYP)-mediated covalent DNA adducts. We now identified the ellipticine metabolites formed by human CYPs and elucidated the metabolites responsible for DNA binding. The 7-hydroxyellipticine, 9-hydroxyellipticine, 12-hydroxyellipticine, 13-hydroxyellipticine, and ellipticine N2-oxide are generated by hepatic microsomes from eight human donors. The role of specific CYPs in the oxidation of ellipticine and the role of the ellipticine metabolites in the formation of DNA adducts were investigated by correlating the levels of metabolites formed in each microsomal sample with CYP activities and with the levels of the ellipticine-derived deoxyguanosine adducts in DNA. On the basis of this analysis, formation of 9-hydroxyellipticine and 7-hydroxyellipticine was attributable to CYP1A1/2, whereas production of 13-hydroxyellipticine and ellipticine N2-oxide, the metabolites responsible for formation of two major DNA adducts, was attributable to CYP3A4. Using recombinant human enzymes, oxidation of ellipticine to 9-hydroxyellipticine and 7-hydroxyellipticine by CYP1A1/2 and to 13-hydroxyellipticine and N2-oxide by CYP3A4 was corroborated. Homologue modeling and docking of ellipticine to the CYP3A4 active center was used to explain the predominance of ellipticine oxidation by CYP3A4 to 13-hydroxyellipticine and N2-oxide.
Metallothionein-I/II Double Knockout Mice Are Hypersensitive to Lead-Induced Kidney Carcinogenesis
Authors: Waalkes Michael P. , Liu Jie , Goyer Robert A. , Diwan Bhalchandra A. 
Published: September 2005

Abstract
Lead is an environmental nephrotoxicant and probable human carcinogen. Elucidating factors predisposing populations to lead toxicity is an important public health issue. Recently, we found that metallothionein-I/-II double knockout (metallothionein-null) mice that are unable to produce the major forms of metallothionein do not produce lead inclusion bodies, which are thought to mitigate lead toxicity, and were sensitive to the subchronic toxic effects of lead exposure (10 weeks), showing modestly diminished renal function and nephromegaly compared with wild-type (WT) mice. It is unclear how this knockout might impact lead carcinogenesis. Thus, the effects of lead(II) acetate were tested in groups (n = 25) of male metallothionein-null and WT mice receiving drinking water with 0, 1,000, 2,000, or 4,000 parts per million lead for up to 104 weeks. Renal proliferative lesions (adenoma and cystic tubular atypical hyperplasia) were much more common and more severe in lead-exposed metallothionein-null mice than in WT mice. A metastatic renal cell carcinoma also occurred in a lead-treated metallothionein-null mouse, whereas none occurred in WT mice. Lead-induced renal proliferative lesions showed marked overexpression of cyclin D1, a common feature of human renal tumors. Renal lead-containing nuclear inclusion bodies were frequently observed in WT mice but did not form in metallothionein-null mice. Metallothionein was often found associated with the outer portion of these inclusion bodies. Thus, the metallothionein-null mice cannot form renal inclusion bodies, even after protracted lead exposure, and this increases the carcinogenic potential of lead. Poor production of metallothionein may predispose human populations to lead carcinogenicity.
NIMA-Related Protein Kinase 1 Is Involved Early in the Ionizing Radiation-Induced DNA Damage Response
Authors: Polci Rosaria , Peng Aimin , Chen Phang-Lang , Riley Daniel J. , Chen Yumay 
Published: September 2005

Abstract
Cellular functions of the NimA-related mammalian kinase Nek1 have not been demonstrated to date. Here we show that Nek1 is involved early in the DNA damage response induced by ionizing radiation (IR) and that Nek1 is important for cells to repair and recover from DNA damage. When primary or transformed cells are exposed to IR, Nek1 kinase activity is increased within 4 minutes, and Nek1 expression is up-regulated shortly thereafter and sustained for hours. At the same early time frame after IR that its kinase activity is highest, a portion of Nek1 redistributes in cells from cytoplasm to discrete nuclear foci at sites of DNA double-strand breaks. There it colocalizes with γ-H2AX and NFBD1/MDC1, two key proteins involved very early in the response to IR-induced DNA double-strand breaks. Finally, Nek1-deficient fibroblasts are much more sensitive to the effects of IR-induced DNA damage than otherwise identical fibroblasts expressing Nek1. These results suggest that Nek1 may function as a kinase early in the DNA damage response pathway.
The FLT3 Internal Tandem Duplication Mutation Prevents Apoptosis in Interleukin-3-Deprived BaF3 Cells Due to Protein Kinase A and Ribosomal S6 Kinase 1–Mediated BAD Phosphorylation at Serine 112
Authors: Yang Xinping , Liu Liyun , Sternberg David , Tang Liren , Galinsky Ilene , DeAngelo Daniel , Stone Richard 
Published: September 2005

Abstract
Internal tandem duplication (ITD) mutations in the FLT3 tyrosine kinase have been detected in ∼20% of acute myeloid leukemia (AML) patients. Patients harboring FLT3/ITD mutations have a relatively poor prognosis. FLT3/ITD results in constitutive autophosphorylation of the receptor and factor-independent survival. Previous studies have shown that FLT3/ITD activates the signal transducers and activators of transcription 5 (STAT5), p42/p44 mitogen-activated protein kinase [MAPK; extracellular signal-regulated kinase (ERK) 1/2], and phosphatidylinositol 3-kinase/Akt pathways. We herein provide biochemical and biological evidence that ribosomal S6 kinase 1 (RSK1) and protein kinase A (PKA) are the two principal kinases that mediate the antiapoptotic function of FLT3/ITD via phosphorylation of BAD at Ser112. Inhibiting both MAPK kinase (MEK)/ERK and PKA pathways by a combination of U0126 (10 μmol/L) and H-89 (5 μmol/L) reduced most of BAD phosphorylation at Ser112 and induced apoptosis to a level comparable with that induced by FLT3 inhibitor AG1296 (5 μmol/L) in BaF3/FLT3/ITD cells. RNA interference of RSK1 or PKA catalytic subunit reduced BAD phosphorylation and induced apoptosis. The MEK inhibitor U0126 and/or the PKA inhibitor H-89 greatly enhanced the efficacy of the FLT3 inhibitor AG1296, suggesting that combining FLT3/ITD downstream pathway inhibition with FLT3 inhibitors may be a viable therapeutic strategy for AML caused by a FLT3/ITD mutation.
Polycyclic Aromatic Hydrocarbon-DNA Adducts in Prostate Cancer
Authors: Rybicki Benjamin A. , Rundle Andrew , Savera Adnan T. , Sankey Steadman S. , Tang Deliang 
Published: September 2005

Abstract
The formation of DNA adducts can lead to DNA replication errors and the potential for carcinogenesis. DNA adducts have been detected in prostate cells, but the distribution of adducts with respect to prostate cancer risk factors and histology is unknown. In a study of 130 Caucasian (n = 61) and African-American (n = 69) men with prostate cancer who underwent radical prostatectomy, we quantified polycyclic aromatic hydrocarbon (PAH)-DNA adducts in prostate tumor and adjacent nontumor cells by immunohistochemistry. A strong correlation between paired adduct levels in the two cell types was observed (r = 0.56; P &lt; 0.0001); however, nontumor cells had a significantly higher level of adducts compared with tumor (0.30 absorbance units ± 0.05 versus 0.17 absorbance units ± 0.04; P &lt; 0.0001). Variables significantly associated with PAH-DNA adduct levels in tumor cells included primary Gleason grade, tumor volume, and log-transformed prostate-specific antigen (PSA) at time of diagnosis. Tumors with a primary Gleason grade of 5 had significantly lower PAH-DNA adduct levels than tumor cells with a primary Gleason grade of 3 or 4 (P &lt; 0.0001 for both). Tumors that involved 10% or less of the prostate gland had significantly higher PAH-DNA adduct levels than tumors that involved 15 to 20% of the prostate gland (P = 0.004). PSA levels were inversely associated with PAH-DNA adduct levels in tumor cells (P = 0.009). A similar, albeit less significant, inverse association was observed between PSA and PAH-DNA adduct levels in nontumor cells (P = 0.07). Interestingly, increasing primary Gleason grade was associated with increasing PAH-DNA adduct levels in adjacent nontumor cells (P = 0.008). Our results show that PAH-DNA adducts are present in the prostate but vary with regard to cellular histology. In prostate tumor cells, decreased cellular differentiation and increased tumor proliferation may reduce PAH-DNA adduct levels.
Small In-Frame Deletion in the Epidermal Growth Factor Receptor as a Target for ZD6474
Authors: Arao Tokuzo , Fukumoto Hisao , Takeda Masayuki , Tamura Tomohide , Saijo Nagahiro , Nishio Kazuto 
Published: September 2005

Abstract
ZD6474 is an inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2/KDR) tyrosine kinase, with additional activity against epidermal growth factor receptor (EGFR) tyrosine kinase. ZD6474 inhibits angiogenesis and growth of a wide range of tumor models in vivo. Gefitinib (“Iressa”) is a selective EGFR tyrosine kinase inhibitor that blocks signal transduction pathways implicated in cancer cell proliferation. Here, the ability of gefitinib and ZD6474 to inhibit tumor cell proliferation was examined directly in eight cancer cell lines in vitro, and a strong correlation was noted between the IC50 values of gefitinib and ZD6474 (r = 0.79). No correlation was observed between the sensitivity to ZD6474 and the level of EGFR or VEGFR expression. The NSCLC cell line PC-9 was seen to be hypersensitive to gefitinib and ZD6474, and a small (15-bp) in-frame deletion of an ATP-binding site (exon 19) in the EGFR was detected (delE746-A750–type deletion). To clarify the involvement of the deletional mutation of EGFR in the cellular sensitivity to ZD6474, we examined the effect of this agent on HEK293 stable transfectants expressing deletional EGFR that designed as the same deletion site observed in PC-9 cells (293-pΔ15). These cells exhibited a 60-fold higher sensitivity to ZD6474 compared with transfectants expressing wild-type EGFR. ZD6474 inhibited the phosphorylation of the mutant EGFR by 10-fold compared with cells with wild-type EGFR. In conclusion, the findings suggested that a small in-frame deletion in the EGFR increased the cellular sensitivity to ZD6474.
NOD2
3020insC Alone Is Not Sufficient for Colorectal Cancer Predisposition
Authors: Alhopuro Pia , Ahvenainen Taru , Mecklin Jukka-Pekka , Juhola Matti , Järvinen Heikki J. , Karhu Auli , Aaltonen Lauri A. 
Published: September 2005

Abstract
Mutations in NOD2 have been shown to associate with increased susceptibility to Crohn’s disease. A recent Polish study linked the truncating NOD2 3020insC variant with an increased risk of colorectal cancer (CRC) at an older age (&gt;50 years) of disease onset, with an odds ratio of 2.23. We studied the possible contribution of the 3020insC variant to CRC risk in a series of 1,042 Finnish population-based patients from which 926 samples were successfully analyzed and in 348 anonymous cancer-free controls. The frequency of the 3020insC mutation was 3.7% in both CRC patients (34 of 926, including 1 homozygote) and cancer-free controls (13 of 348; odds ratio, 0.98; confidence interval, 0.51–1.88). Contrary to the Polish study, there was no significant difference in the mutation rates between CRC patients &gt; 50 years of age (25 of 576; 4.3%) and controls in the present series. We studied respective tumor tissue DNAs of all patients displaying heterozygous 3020insC changes for loss of heterozygosity. Loss of heterozygosity at NOD2 was observed in only 1 of the 33 CRC samples. Our results suggest that NOD2 3020insC alone does not contribute to CRC risk. If this variant predisposes to CRC, additional factors not present in the Finnish population need to be involved.
Mitogen- and Stress-Activated Protein Kinase 1 Activity and Histone H3 Phosphorylation in Oncogene-Transformed Mouse Fibroblasts
Authors: Drobic Bojan , Espino Paula S. , Davie James R. 
Published: September 2005

Abstract
Activation of the Ras-Raf-mitogen-activated protein/extracellular signal-regulated kinase (ERK) kinase-ERK signal transduction pathway or the SAPK2/p38 pathway results in the activation of mitogen- and stress-activated protein kinase 1 (MSK1). This activation of MSK1 leads to a rapid phosphorylation of histone H3 at Ser10. Previously, we had demonstrated that Ser10 phosphorylated H3 was elevated in Ciras-3 (c-Ha-ras–transformed 10T1 2) mouse fibroblasts and that H3 phosphatase activity was similar in Ciras-3 and 10T1 2 cells. Here, we demonstrate that the activities of ERK and MSK1, but not p38, are elevated in Ciras-3 cells relative to these activities in the parental 10T1 2 cells. Analyses of the subcellular distribution of MSK1 showed that the H3 kinase was similarly distributed in Ciras-3 and 10T1 2 cells, with most MSK1 being present in the nucleus. In contrast to many other chromatin modifying enzymes, MSK1 was loosely bound in the nucleus and was not a component of the nuclear matrix. Our results provide evidence that oncogene-mediated activation of the Ras-mitogen-activated protein kinase signal transduction pathway elevates the activity of MSK1, resulting in the increased steady-state levels of phosphorylated H3, which may contribute to the chromatin decondensation and aberrant gene expression observed in these cells.
Adenoviral E1A Targets Mdm4 to Stabilize Tumor Suppressor p53
Authors: Li Zheng , Day Chi-Ping , Yang Jer-Yen , Tsai Wen-Bin , Lozano Guillermina , Shih Hsiu-Ming , Hung Mien-Chie 
Published: September 2005

Abstract
The adenoviral protein E1A associates with multiple anticancer activities, including stabilization of p53 tumor suppressor, and has been tested through gene therapy approaches in clinical trials. To identify potential E1A-binding proteins involved in E1A’s anticancer activities, we screened a yeast two-hybrid library and identified Mdm4, an Mdm2-related p53-binding protein, as a novel E1A-binding protein. The NH2-terminal region of Mdm4 and the CR1 domain of E1A were required for the interaction between E1A and Mdm4. E1A preferentially bound to Mdm4 rather than Mdm2 and formed a complex with p53 in the presence of Mdm4, resulting in the stabilization of p53 in a p14ARF-independent manner. E1A failed to stabilize p53 in the absence of Mdm4, showing that Mdm4 was required for p53 stabilization by E1A. Moreover, E1A-mediated stabilization of p53 occurred in nucleus. Although it had no effect on the p53-Mdm2 interaction, E1A facilitated Mdm4 binding to p53 and inhibited Mdm2 binding to Mdm4, resulting in decreased nuclear exportation of p53. Thus, our findings highlighted a novel mechanism, whereby E1A stabilized the p53 tumor suppressor through Mdm4.
Cyclin B1 Is a Critical Target of RhoB in the Cell Suicide Program Triggered by Farnesyl Transferase Inhibition
Authors: Kamasani Uma , Huang Minzhou , DuHadaway James B. , Prochownik Edward V. , Donover P. Scott , Prendergast George C. 
Published: September 2005

Abstract
Farnesyl transferase inhibitors (FTIs) have displayed limited efficacy in clinical trials, possibly because of their relatively limited cytotoxic effects against most human cancer cells. Therefore, efforts to leverage the clinical utility of FTIs may benefit from learning how these agents elicit p53-independent apoptosis in mouse models of cancer. Knockout mouse studies have established that gain of the geranylgeranylated isoform of the small GTPase RhoB is essential for FTI to trigger apoptosis. Here we demonstrate that Cyclin B1 is a crucial target for suppression by RhoB in this death program. Steady-state levels of Cyclin B1 and its associated kinase Cdk1 were suppressed in a RhoB-dependent manner in cells fated to undergo FTI-induced apoptosis. These events were not derivative of cell cycle arrest, because they did not occur in cells fated to undergo FTI-induced growth inhibition. Mechanistic investigations indicated that RhoB mediated transcriptional suppression but also accumulation of Cyclin B1 in the cytosol at early times after FTI treatment, at a time before the subsequent reduction in steady-state protein levels. Enforcing Cyclin B1 expression attenuated apoptosis but not growth inhibition triggered by FTI. Moreover, enforcing Cyclin B1 abolished FTI antitumor activity in graft assays. These findings suggest that Cyclin B1 suppression is a critical step in the mechanism by which FTI triggers apoptosis and robust antitumor efficacy. Our findings suggest that Cyclin B1 suppression may predict favorable clinical responses to FTI, based on cytotoxic susceptibility, and they suggest a rational strategy to address FTI nonresponders by coinhibition of Cdk1 activity.
Significant Contribution of Germline
BRCA2
Rearrangements in Male Breast Cancer Families
Authors: Tournier Isabelle , Paillerets Brigitte Bressac-de , Sobol Hagay , Stoppa-Lyonnet Dominique , Lidereau Rosette , Barrois Michel , Mazoyer Sylvie , Coulet Florence , Hardouin Agnès , Chompret Agnès , Lortholary Alain , Chappuis Pierre , Bourdon Violaine , Bonadona Valérie , Maugard Christine , Gilbert Brigitte , Nogues Catherine , Frébourg Thierry , Tosi Mario 
Published: September 2005

Abstract
Although screening for large deletions or duplications of the BRCA1 gene is becoming a routine component of the molecular diagnosis of familial breast cancer, little is known about the occurrence of such rearrangements in the BRCA2 gene. Because of the high frequency of BRCA2 mutations in breast cancer families with at least one case of male breast cancer, we selected a cohort of 39 such families, tested negative for mutations in the coding regions of BRCA1 and BRCA2, and developed an assay for BRCA2 rearrangements, based on quantitative multiplex PCR of short fluorescent fragments (QMPSF). We found three rearrangements: (1) a deletion of exons 12 and 13; (2) a duplication of exons 1 and 2; and (3) a complete deletion of BRCA2. We determined the boundaries of the deletion of exons 12 and 13, showing that it resulted from an unequal recombination between Alu sequences. We mapped the complete BRCA2 deletion, which extends over at least 298 kb and showed that it does not affect APRIN/AS3, previously characterized as a tumor suppressor gene, but it comprises several loci corresponding to proven or putative transcripts of unknown functional significance. These data suggest that screening for BRCA2 rearrangements should be done, especially in male breast cancer families tested negative for BRCA1 and BRCA2 mutations.
Elimination of Hepatic Metastases of Colon Cancer Cells via p53-Independent Cross-Talk between Irinotecan and Apo2 Ligand/TRAIL
Authors: Ravi Rajani , Jain Ajay J. , Schulick Richard D. , Pham Vui , Prouser Traci S. , Allen Heather , Mayer Elizabeth Garrett , Yu Hua , Pardoll Drew M. , Ashkenazi Avi , Bedi Atul 
Published: September 2005

Abstract
The majority of colorectal cancers have lost/inactivated the p53 tumor suppressor gene. Using isogenic human colon cancer cells that differ only in their p53 status, we demonstrate that loss of p53 renders tumor cells relatively resistant to the topoisomerase I inhibitor, irinotecan. Whereas irinotecan-induced up-regulation of the proapoptotic proteins PUMA and Noxa requires p53, we find that irinotecan inhibits Janus kinase 2 (JAK2)-signal transducer and activator of transcription 3 and 5 (STAT3/5) signaling in both p53-proficient and p53-deficient tumor cells. We show that irinotecan inhibits JAK2-STAT3/5-dependent expression of survival proteins (Bcl-xL and XIAP) and cooperates with Apo2 ligand/tumor necrosis factor-related apoptosis-inducing ligand (Apo2L/TRAIL) to facilitate p53-independent apoptosis of colon cancer cells. Whereas xenografts of p53-deficient colon cancer cells are relatively resistant to irinotecan compared with their p53-proficient counterparts, combined treatment with irinotecan and Apo2L/TRAIL eliminates hepatic metastases of both p53-proficient and p53-deficient cancer cells in vivo and significantly improves the survival of animals relative to treatment with either agent alone. Although the synergy between chemotherapy and Apo2L/TRAIL has been ascribed to p53, our data demonstrate that irinotecan enhances Apo2L/TRAIL-induced apoptosis of tumor cells via a distinct p53-independent mechanism involving inhibition of JAK2-STAT3/5 signaling. These findings identify a novel p53-independent channel of cross-talk between topoisomerase I inhibitors and Apo2L/TRAIL and suggest that the addition of Apo2L/TRAIL can improve the therapeutic index of irinotecan against both p53-proficient and p53-deficient colorectal cancers, including those that have metastasized to the liver.