bluuebunny/crossref_metadata_2025_split huggingface dataset:
Smad7 Sensitizes Tumor Necrosis Factor–Induced Apoptosis through the Inhibition of Antiapoptotic Gene Expression by Suppressing Activation of the Nuclear Factor-κB Pathway
Authors: Hong Suntaek , Lee Chan , Kim Seong-Jin 
Published: October 2007

AbstractAlthough tumor necrosis factor (TNF) induces apoptosis and cell death in many tumor cells, some cancer cells are still resistant to the TNF-induced death signal. In this report, we showed that Smad7, an inhibitory Smad of transforming growth factor-β (TGF-β) signaling, can overcome the TNF resistance in human breast and gastric cancer cells. Overexpression of Smad7 induces the degradation of poly(ADP-ribose) polymerase and the activation of caspase cascade. Although c-Jun NH2-terminal kinase (JNK) signaling is involved in TNF-induced cell death, the expression of Smad7 does not synergize the activation of JNK. However, the activation of nuclear factor-κB (NF-κB), the cell survival factor, is markedly decreased in Smad7-stable cells. Furthermore, the expression of antiapoptotic target genes of NF-κB is significantly reduced in accordance with the level of Smad7. In addition, Smad7 mediates the inhibitory activity of TGF-β on TNF-induced NF-κB activation and the synergistic activity of TGF-β on TNF-induced apoptosis. These findings suggest that Smad7 sensitizes the tumor cells to TNF-induced apoptosis through the inhibition of expression of antiapoptotic NF-κB target genes. [Cancer Res 2007;67(19):9577–83]
The Phosphoinositide Kinase PIKfyve Mediates Epidermal Growth Factor Receptor Trafficking to the Nucleus
Authors: Kim Jayoung , Jahng Wan Jin , Di Vizio Dolores , Lee Julie S. , Jhaveri Raj , Rubin Mark A. , Shisheva Assia , Freeman Michael R. 
Published: October 2007

Abstract
ErbB receptor tyrosine kinases can transit to nuclei in tumor cells, where they have been shown to regulate gene expression as components of transcriptional complexes. Quantitative analysis of a human bladder cancer tissue microarray identified nuclear epidermal growth factor receptor (EGFR) in tumor cells and also showed an increased frequency of this histologic feature in cancer relative to normal tissues. This observation suggests a potential role for nuclear EGFR in bladder cancer. We confirmed that EGFR could be induced to transit to nuclei in cultured human bladder cancer cells in response to the urothelial cell growth factor and EGFR ligand heparin-binding EGF-like growth factor (HB-EGF). Mass spectrometric analysis of EGFR immune complexes from a transitional carcinoma cell line (TCCSUP) identified the phosphoinositide kinase, PIKfyve, as a potential component of the EGFR trafficking mechanism. RNA silencing indicated that PIKfyve is a mediator of HB-EGF–stimulated EGFR nuclear trafficking, EGFR binding to the cyclin D1 promoter, and cell cycle progression. These results identify a novel mediator of the EGFR transcription function and further suggest that nuclear EGFR and the lipid kinase PIKfyve may play a role in bladder oncogenesis. [Cancer Res 2007;67(19):9229–37]
Relocalized p27Kip1 Tumor Suppressor Functions as a Cytoplasmic Metastatic Oncogene in Melanoma
Authors: Denicourt Catherine , Saenz Cheryl C. , Datnow Brian , Cui Xian-Shu , Dowdy Steven F. 
Published: October 2007

AbstractThe p27 tumor suppressor negatively regulates G1 cell cycle progression. However, human malignancies rarely select for deletion/inactivation of p27, a hallmark of tumor suppressor genes. Instead, p27 is degraded or relocalized to the cytoplasm in aggressive malignancies, supporting the notion that p27 sequestration from its nuclear cyclin:cyclin-dependent kinase (cdk) targets is critical. However, emerging cell biology data suggest a novel cdk-independent cytoplasmic function of p27 in cell migration. Here, we find cytoplasmic p27 in 70% of invasive and metastatic melanomas. In contrast, no cytoplasmic p27 was detected in noninvasive, basement membrane–confined melanoma in situ, suggesting a late oncogenic role for cytoplasmic p27 in metastasis. Targeted cytoplasmic expression of wild-type or non–cdk-binding p27 at subphysiologic levels induced melanoma motility and resulted in numerous metastases to lymph node, lung, and peritoneum. These observations point to a prominent role of cytoplasmic p27 in metastatic disease that is independent of cyclin:cdk regulation or mere nuclear loss. [Cancer Res 2007;67(19):9238–43]
Definition of Functionally Important Mechanistic Differences among Selective Estrogen Receptor Down-regulators
Authors: Wittmann Bryan M. , Sherk Andrea , McDonnell Donald P. 
Published: October 2007

Abstract
One subclass of antiestrogens, the selective estrogen receptor down-regulators (SERDs), have received considerable attention of late as they competitively inhibit estrogen binding and induce a rapid, proteasome-dependent degradation of the receptor. Contained within this class of molecules is the steroidal antiestrogen ICI182,780 (faslodex), recently approved for the treatment of metastatic cancer, and GW5638/DPC974, a SERD that is currently being evaluated in the clinic. Given that mechanistic differences between different selective estrogen receptor modulators have been translated into important clinical profiles, it was of interest to determine if the SERD subclass of ligands were likewise functionally or mechanistically distinguishable. In this study, we show that although the steroidal and nonsteroidal SERDs target ERα for degradation, the underlying mechanism(s) are different. Of note was the identification of a specific protein-protein interaction surface presented on ERα in the presence of the ICI182,780-activated receptor which is required for degradation. Interestingly, this surface is also presented on ERα in the presence of RU58,668, a SERD that is chemically distinct from ICI182,780. This surface is not required for GW5638-mediated degradation, and thus, this SERD seems to affect ERα down-regulation by a different mechanism. These data suggest that sequencing of therapies using drugs of this class is likely to be possible. Finally, because of the unmet need for orally active SERDS that function similarly to ICI182,780, we have used the insights from these mechanistic studies to develop and validate a high-throughput screen for compounds of this class with improved pharmaceutical properties. [Cancer Res 2007;67(19):9549–60]
Tumor Necrosis Factor α Mediates Homogeneous Distribution of Liposomes in Murine Melanoma that Contributes to a Better Tumor Response
Authors: Seynhaeve Ann L.B. , Hoving Saske , Schipper Debby , Vermeulen Cindy E. , aan de Wiel-Ambagtsheer Gisela , van Tiel Sandra T. , Eggermont Alexander M.M. , ten Hagen Timo L.M. 
Published: October 2007

Abstract
Successful treatment of solid tumors with chemotherapeutics requires that adequate levels reach the tumor cells. Tumor vascular normalization has been proposed to enhance drug delivery and improve tumor response to chemotherapy. Differently, augmenting leakage of the tumor-associated vasculature, and as such enhance vascular abnormality, may improve tumor response as well. In the present study, we show that addition of low-dose tumor necrosis factor α (TNF) to systemic injections with pegylated long circulating liposomes augmented the tumor accumulation of these liposomes 5- to 6-fold, which strongly correlated with enhanced tumor response. Using intravital microscopy, we could study the liposomal distribution inside the tumor in more detail. Especially 100 nm liposomes effectively extravasate in the surrounding tumor tissue in the presence of TNF and this occurred without any effect on tumor vascular density, branching, and diameter. Next to that, we observed in living animals that tumor cells take up the liposomes intact, followed by intracellular degradation. To our knowledge, this is an unprecedented observation. Taken together, TNF renders more tumor vessels permeable, leading to a more homogeneous distribution of the liposomes throughout the tumor, which is crucial for an optimal tumor response. We conclude that delivery of nanoparticulate drug formulations to solid tumor benefits from augmenting the vascular leakage through vascular manipulation with vasoactive drugs like TNF. [Cancer Res 2007;67(19):9455–62]
Trastuzumab-Resistant HER2-Driven Breast Cancer Cells Are Sensitive to Epigallocatechin-3 Gallate
Authors: Eddy Sean F. , Kane Susan E. , Sonenshein Gail E. 
Published: October 2007

Abstract
Overexpression of the epidermal growth factor receptor family member HER2 is found in ∼30% of breast cancers and is a target for immunotherapy. Trastuzumab, a humanized monoclonal antibody against HER2, is cytostatic when added alone and highly successful in clinical settings when used in combination with other chemotherapeutic agents. Unfortunately, HER2 tumors in patients develop resistance to trastuzumab or metastasize to the brain, which is inaccessible to antibody therapy. Previously, we showed that the green tea polyphenol epigallocatechin-3 gallate (EGCG) inhibits growth and transformed phenotype of Her-2/neu–driven mouse mammary tumor cells. The different modes of action of EGCG and trastuzumab led us to hypothesize that EGCG will inhibit HER2-driven breast cancer cells resistant to trastuzumab. We studied trastuzumab-resistant BT474 human breast cancer cells, isolated by chronic trastuzumab exposure, and JIMT-1 breast cancer cells, derived from a pleural effusion in a patient who displayed clinical resistance to trastuzumab therapy. EGCG treatment caused a dose-dependent decrease in growth and cellular ATP production, and apoptosis at high concentrations. Akt activity was suppressed by EGCG leading to the induction of FOXO3a and target cyclin-dependent kinase inhibitor p27Kip1 levels. Thus, EGCG in combination with trastuzumab may provide a novel strategy for treatment of HER2-overexpressing breast cancers, given that EGCG can cross the blood-brain barrier. [Cancer Res 2007;67(19):9018–23]
The Alternative Reading Frame Tumor Suppressor Antagonizes Hypoxia-Induced Cancer Cell Migration via Interaction with the COOH-Terminal Binding Protein Corepressor
Authors: Paliwal Seema , Kovi Ramesh C. , Nath Bharath , Chen Ya-Wen , Lewis Brian C. , Grossman Steven R. 
Published: October 2007

Abstract
The alternative reading frame (ARF) tumor suppressor exerts both p53-dependent and p53-independent activities critical to the prevention of cancer in mice and humans. Recent evidence from mouse models suggests that when p53 is absent, further loss of ARF can widen the tumor spectrum, and potentiate invasion and metastasis. A major target of the p53-independent activity of ARF is the COOH-terminal binding protein (CtBP) family of metabolically regulated transcriptional corepressors, which are degraded upon acute exposure to the ARF protein. CtBPs are activated under conditions of metabolic stress, such as hypoxia, to repress epithelial and proapoptotic genes, and can mediate hypoxia-induced migration of cancer cells. The possibility that ARF could suppress tumor cell migration as part of its p53-independent activities was thus explored. Small-interfering RNA (siRNA)–mediated knockdown of ARF in human lung carcinoma cells led to increased cell migration, especially during hypoxia, and this effect was blocked by concomitant treatment with CtBP2 siRNA. Introduction of ARF into p53 and ARF-null human colon cancer cells inhibited hypoxia-induced migration. Furthermore, overexpression of CtBP2 in ARF-expressing cells enhanced cell migration, and an ARF mutant defective in CtBP-family binding was impaired in its ability to inhibit cell migration induced by CtBP2. ARF depletion or CtBP2 overexpression was associated with decreased PTEN expression and activation of the phosphatidylinositol 3-kinase pathway, and a phosphatidylinositol 3-kinase inhibitor blocked CtBP2-mediated cell migration. Thus, ARF can suppress cell migration by antagonizing CtBP2 and the phosphatidylinositol 3-kinase pathway, and these data may explain the increased aggressiveness of ARF-null tumors in mouse models. [Cancer Res 2007;67(19):9322–9]
The Fuzzy Math of Solid Tumor Stem Cells: A Perspective
Authors: Kern Scott E. , Shibata Darryl 
Published: October 2007

Abstract
Apparently effective therapeutic agents very often fail to cure cancer patients. It is therefore attractive to wonder whether a specific resistant cell subset should be recognized and separately targeted. In solid tumors, such as carcinomas, a minor population of “cancer stem cells” has been proposed and sought experimentally in human tumors and isolated cell populations. It is often overlooked that the rationale and supportive data are essentially numerical and can be evaluated as such. A reevaluation of the published studies and related claims within awarded U.S. patents suggests that the mathematical support for the concept of therapeutically useful stem cells is weak and may even invalidate the foundations of these publications and patent claims. Mathematical arguments should be used more consistently, because they can serve as a guide for interpreting studies into cancer stem cells of solid tumors. [Cancer Res 2007;67(19):8985–8]
Autocrine Glutamate Signaling Promotes Glioma Cell Invasion
Authors: Lyons Susan A. , Chung W. Joon , Weaver Amy K. , Ogunrinu Toyin , Sontheimer Harald 
Published: October 2007

Abstract
Malignant gliomas have been shown to release glutamate, which kills surrounding brain cells, creating room for tumor expansion. This glutamate release occurs primarily via system xC−, a Na+-independent cystine-glutamate exchanger. We show here, in addition, that the released glutamate acts as an essential autocrine/paracrine signal that promotes cell invasion. Specifically, chemotactic invasion and scrape motility assays each show dose-dependent inhibition of cell migration when glutamate release was inhibited using either S-(4)-CPG or sulfasalazine, both potent blockers of system xC−. This inhibition could be overcome by the addition of exogenous glutamate (100 μmol/L) in the continued presence of the inhibitors. Migration/invasion was also inhibited when Ca2+-permeable α-amino-3-hydroxy-5-methylisoxazole-4-propionic acid receptors (AMPA-R) were blocked using GYKI or Joro spider toxin, whereas CNQX was ineffective. Ca2+ imaging experiments show that the released glutamate activates Ca2+-permeable AMPA-R and induces intracellular Ca2+ oscillations that are essential for cell migration. Importantly, glioma cells release glutamate in sufficient quantities to activate AMPA-Rs on themselves or neighboring cells, thus acting in an autocrine and/or paracrine fashion. System xC− and the appropriate AMPA-R subunits are expressed in all glioma cell lines, patient-derived glioma cells, and acute patient biopsies investigated. Furthermore, animal studies in which human gliomas were xenographed into scid mice show that chronic inhibition of system xC−–mediated glutamate release leads to smaller and less invasive tumors compared with saline-treated controls. These data suggest that glioma invasion is effectively disrupted by inhibiting an autocrine glutamate signaling loop with a clinically approved candidate drug, sulfasalazine, already in hand. [Cancer Res 2007;67(19):9463–71]
Nitric Oxide Inactivates the Retinoblastoma Pathway in Chronic Inflammation
Authors: Ying Lei , Hofseth Anne B. , Browning Darren D. , Nagarkatti Mitzi , Nagarkatti Prakash S. , Hofseth Lorne J. 
Published: October 2007

Abstract
Patients with chronic inflammatory bowel disease have a high risk of colon cancer. The molecules that initiate and promote colon cancer and the cancer pathways altered remain undefined. Here, using in vitro models and a mouse model of colitis, we show that nitric oxide (NO) species induce retinoblastoma protein (pRb) hyperphosphorylation and inactivation, resulting in increased proliferation through the pRb-E2F1 pathway. NO-driven pRb hyperphosphorylation occurs through soluble guanylyl cyclase/guanosine 3′,5′-cyclic monophosphate signaling and is dependent on the mitogen-activated protein kinase/extracellular signal-regulated kinase kinase MEK/ERK and phosphatidylinositol 3-kinase/AKT pathways. Our results reveal a link between NO and pRb inactivation and provide insight into molecules that can be targeted in the prevention of the inflammation-to-cancer sequence. [Cancer Res 2007;67(19):9286–93]
A Phase II Study of Gefitinib Monotherapy in Advanced Esophageal Adenocarcinoma: Evidence of Gene Expression, Cellular, and Clinical Response
Authors: Ferry David R. , Anderson Mark , Beddard Kate , Tomlinson Simon , Atherfold Paul , Obszynska Jolanta , Harrison Rebecca , Jankowski Janusz 
Published: October 2007

AbstractPurpose: At presentation, most cases of adenocarcinoma of the esophagus (ACE) are inoperable. Although chemotherapy can prolong survival, patients eventually die as a result of refractory disease. Epidermal growth factor receptor (EGFR) is almost universally expressed in ACE and is a negative prognostic factor.Experimental Design: This open-label, two-center, noncomparative, two-part phase II trial assessed the EGFR tyrosine kinase inhibitor gefitinib (500 mg/d) in patients with advanced, inoperable ACE. The primary end point was tumor response. The effect of EGFR inhibition was also evaluated by gene expression analysis of tumor biopsies taken before gefitinib treatment and 28 days after.Results: Twenty-seven patients were recruited and evaluable for tumor response and safety. Three patients had a partial response and seven had stable disease, giving a disease control rate (partial response + stable disease) of 37%. Drug-related adverse events were generally mild: diarrhea in 19 (grade 3 in three) and rash in 19 (grade 3 in five) patients, and there were no grade 4 drug-related adverse events. Microarray experiments on tumor biopsies showed that gefitinib also down-regulated oncogenes associated with tumor progression. Ki67 (a marker of tumor growth) expression decreased in five of seven biopsies taken before and after treatment.Conclusion: Gefitinib (500 mg/d) is an active and generally well-tolerated treatment for ACE. Studies on endoscopic biopsies are feasible and indicate that gefitinib inhibits both gene expression and cellular biology at 500 mg/d, and these may provide surrogate end points for predictive biomarkers. Further trials of gefitinib are warranted, particularly as patient response seems to be durable and current second-line chemotherapy options have no proven ability to prolong life.
Phase I Trial of Poly-l-Glutamate Camptothecin (CT-2106) Administered Weekly in Patients with Advanced Solid Malignancies
Authors: Homsi Jade , Simon George R. , Garrett Chris R. , Springett Gregory , De Conti Ronald , Chiappori Alberto A. , Munster Pamela N. , Burton Michelle K. , Stromatt Scott , Allievi Claudia , Angiuli Patrizia , Eisenfeld Amy , Sullivan Daniel M. , Daud Adil I. 
Published: October 2007

Abstract
Purpose: CT-2106 is a 20(S)-camptothecin poly-l-glutamate conjugate. This linkage stabilizes the active lactone form of camptothecin and enhances aqueous solubility. In addition, poly-l-glutamate is postulated to increase tumor delivery of the active compound through enhanced permeability and retention effect in tumor. We studied a weekly schedule of CT-2106 in patients with refractory solid tumor malignancies.
Experimental Design: CT-2106 was infused (10 min i.v. infusion) on days 1, 8, and 15 of each 28-day cycle. Plasma and urine were analyzed for total and unconjugated camptothecin by high-performance liquid chromatography equipped with a fluorescence detector. Toxicity and response assessments were done with Common Toxicity Criteria for Adverse Events version 3 and Response Evaluation Criteria in Solid Tumors, respectively.
Results: Twenty-six patients were enrolled. Median age was 58 years (range, 36-83) and median number of doses was 6 (range, 1-9). The most frequent tumor type (50%) was melanoma. Dose limiting toxicities were thrombocytopenia and fatigue. A weekly dose of 25 mg/m2 given every 3 of 4 weeks was the maximum tolerated dose. The majority of grade 3 and 4 toxicities were hematologic. The pharmacokinetic profile of conjugated and unconjugated camptothecin showed a polyexponential decline with similar terminal half life (t1/2 range was 44-63 and 31-48 h for conjugated and unconjugated, respectively). Pharmacokinetics of conjugated and unconjugated camptothecin were dose and time independent in the tested dose range. Urinary excretion of conjugated and unconjugated camptothecin accounted for about 30% and 4% of the administered dose, respectively.
Conclusions: CT-2106 has a more manageable toxicity profile compared with unconjugated camptothecin. The maximum tolerated dose is 25 mg/m2 weekly given 3 of 4 weeks. This compound results in prolonged release of unconjugated camptothecin.
Amplification of PVT1 Contributes to the Pathophysiology of Ovarian and Breast Cancer
Authors: Guan Yinghui , Kuo Wen-Lin , Stilwell Jackie L. , Takano Hirokuni , Lapuk Anna V. , Fridlyand Jane , Mao Jian-Hua , Yu Mamie , Miller Melinda A. , Santos Jennifer L. , Kalloger Steve E. , Carlson Joseph W. , Ginzinger David G. , Celniker Susan E. , Mills Gordon B. , Huntsman David G. , Gray Joe W. 
Published: October 2007

Abstract
Purpose: This study was designed to elucidate the role of amplification at 8q24 in the pathophysiology of ovarian and breast cancer because increased copy number at this locus is one of the most frequent genomic abnormalities in these cancers.
Experimental Design: To accomplish this, we assessed the association of amplification at 8q24 with outcome in ovarian cancers using fluorescence in situ hybridization to tissue microarrays and measured responses of ovarian and breast cancer cell lines to specific small interfering RNAs against the oncogene MYC and a putative noncoding RNA, PVT1, both of which map to 8q24.
Results: Amplification of 8q24 was associated with significantly reduced survival duration. In addition, small interfering RNA–mediated reduction in either PVT1 or MYC expression inhibited proliferation in breast and ovarian cancer cell lines in which they were both amplified and overexpressed but not in lines in which they were not amplified/overexpressed. Inhibition of PVT1 expression also induced a strong apoptotic response in cell lines in which it was overexpressed but not in lines in which it was not amplified/overexpressed. Inhibition of MYC, on the other hand, did not induce an apoptotic response in cell lines in which MYC was amplified and overexpressed.
Conclusions: These results suggest that MYC and PVT1 contribute independently to ovarian and breast pathogenesis when overexpressed because of genomic abnormalities. They also suggest that PVT1-mediated inhibition of apoptosis may explain why amplification of 8q24 is associated with reduced survival duration in patients treated with agents that act through apoptotic mechanisms.