bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from ErbB3-Dependent Motility and Intravasation in Breast Cancer Metastasis
Authors: Xue Chengsen , Liang Fubo , Mahmood Radma , Vuolo Magalis , Wyckoff Jeffrey , Qian Hong , Tsai Kun-Lin , Kim Mimi , Locker Joseph , Zhang Zhong-Yin , Segall Jeffrey E.
Published: March 2023

Abstract
A better understanding of how epidermal growth factor receptor family members (ErbBs) contribute to metastasis is important for evaluating ErbB-directed therapies. Activation of ErbB3/ErbB2 heterodimers can affect both proliferation and motility. We find that increasing ErbB3-dependent signaling in orthotopic injection models of breast cancer can enhance intravasation and lung metastasis with no effect on primary tumor growth or microvessel density. Enhanced metastatic ability due to increased expression of ErbB2 or ErbB3 correlated with stronger chemotaxis and invasion responses to heregulin β1. Suppression of ErbB3 expression reduced both intravasation and metastasis. A human breast cancer tumor tissue microarray showed a significant association between ErbB3 and ErbB2 expression and metastasis independent of tumor size. These results indicate that ErbB3-dependent signaling through ErbB3/ErbB2 heterodimers can contribute to metastasis through enhancing tumor cell invasion and intravasation in vivo and that ErbB-directed therapies may be useful for the inhibition of invasion independent of effects on tumor growth. (Cancer Res 2006; 66(3): 1418-26)
Data from Tumor Necrosis Factor-α Blocks Apoptosis in Melanoma Cells when BRAF Signaling Is Inhibited
Authors: Gray-Schopfer Vanessa C. , Karasarides Maria , Hayward Robert , Marais Richard
Published: March 2023

Abstract
The protein kinase BRAF, a component of the RAS/RAF/mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK)/ERK signaling pathway, regulates cell fate in response to extracellular signals. Activating mutations in BRAF occur in ∼70% of human melanomas. The active proteins stimulate constitutive pathway signaling, proliferation, and survival. Thus, inhibition of BRAF signaling in melanoma cells causes cell cycle arrest and induces cell death through apoptosis, validating BRAF as an important therapeutic target. Here, we show that the apoptosis induced by inhibition of BRAF signaling in melanoma cells can be prevented if the cells are treated with tumor necrosis factor (TNF)-α. This allows the cells to recover from the inhibition of BRAF signaling and reenter the cell cycle. This effect occurs due to a specific TNF-α and BRAF interaction because TNF-α does not prevent cell death in the presence of cisplatin, nitrogen mustard or thapsigargin. Furthermore, the cytokines Fas ligand, TNF-related apoptosis-inducing ligand, interleukin (IL)-1, and IL-6 do not prevent cell death when BRAF signaling is inhibited. The survival mechanism requires nuclear factor-κB (NF-κB) transcription factor activity, which is strongly induced by TNF-α in these cells. These findings suggest that drugs that target the BRAF/MEK pathway could be combined with agents that target TNF-α and/or NF-κB signaling to provide exciting new therapeutic opportunities for the treatment of melanoma. [Cancer Res 2007;67(1):122–9]
Data from Ataxia Telangiectasia Mutated and Checkpoint Kinase 2 Regulate BRCA1 to Promote the Fidelity of DNA End-Joining
Authors: Wang Hui-Chun , Chou Wen-Cheng , Shieh Sheau-Yann , Shen Chen-Yang
Published: March 2023

Abstract
Homologous recombination (HR) and nonhomologous end-joining (NHEJ) are the two mechanisms responsible for repairing DNA double-strand breaks (DSBs) and act in either a collaborative or competitive manner in mammalian cells. DSB repaired by NHEJ may be more complicated than the simple joining of the ends of DSB, because, if nucleotides were lost, it would result in error-prone repair. This has led to the proposal that a subpathway of precise NHEJ exists that can repair DSBs with higher fidelity; this is supported by recent findings that the expression of the HR gene, BRCA1, is causally linked to in vitro and in vivo precise NHEJ activity. To further delineate this mechanism, the present study explored the connection between NHEJ and the cell-cycle checkpoint proteins, ataxia telangiectasia mutated (ATM) and checkpoint kinase 2 (Chk2), known to be involved in activating BRCA1, and tested the hypothesis that ATM and Chk2 promote precise end-joining by BRCA1. Support for this hypothesis came from the observations that (a) knockdown of ATM and Chk2 expression affected end-joining activity; (b) in BRCA1-defective cells, precise end-joining activity was not restored by a BRCA1 mutant lacking the site phosphorylated by Chk2 but was restored by wild-type BRCA1 or a mutant mimicking phosphorylation by Chk2; (c) Chk2 mutants lacking kinase activity or with a mutation at a site phosphorylated by ATM had a dominant negative effect on precise end-joining in BRCA1-expressing cells. These results suggest that the other two HR regulatory proteins, ATM and Chk2, act jointly to regulate the activity of BRCA1 in controlling the fidelity of DNA end-joining by precise NHEJ. (Cancer Res 2006; 66(3): 1391-400)
Data from TMPRSS2:ERG Fusion by Translocation or Interstitial Deletion Is Highly Relevant in Androgen-Dependent Prostate Cancer, But Is Bypassed in Late-Stage Androgen Receptor–Negative Prostate Cancer
Authors: Hermans Karin G. , van Marion Ronald , van Dekken Herman , Jenster Guido , van Weerden Wytske M. , Trapman Jan
Published: March 2023

Abstract
Recently, a unique fusion between the prostate-specific, androgen-regulated TMPRSS2 gene and the ETS genes ERG, ETV1, or ETV4 has been described in clinical prostate cancer. We investigated mechanisms of expression of four ETS genes, ERG, ETV1, ETV4, and FLI1, in 11 xenografts representing different stages of prostate cancer. All five androgen-dependent xenografts showed as major transcript overexpression of two splice variants of TMPRSS2:ERG, linking TMPRSS2 exon 1 or 2 sequences to ERG exon 4. In one of two androgen-sensitive xenografts, fusion transcripts of TMPRSS2 and ETV1 were detected. Array-based comparative genomic hybridization and interphase fluorescence in situ hybridization indicated both interstitial deletions and translocations as mechanisms of TMPRSS2:ERG gene fusion. Importantly, TMPRSS2 to ERG fusions were also observed in three of four androgen-independent, androgen receptor (AR)–negative xenografts and in two AR-negative clinical prostate cancer specimens; however, the fusion gene was not expressed. In almost all AR-negative tumor samples, overexpression of wild-type ETV4 or FLI1 was detected. Combined, our observations indicate a key role of fusion of TMPRSS2 and ETS genes in most androgen-regulated prostate cancers, which might be bypassed by androgen-independent expression of wild-type ETS factors in late-stage disease. (Cancer Res 2006; 66(22): 10658-63)
Data from Transcriptional Profiling Identifies Cyclin D1 as a Critical Downstream Effector of Mutant Epidermal Growth Factor Receptor Signaling
Authors: Kobayashi Susumu , Shimamura Takeshi , Monti Stefano , Steidl Ulrich , Hetherington Christopher J. , Lowell April M. , Golub Todd , Meyerson Matthew , Tenen Daniel G. , Shapiro Geoffrey I. , Halmos Balázs
Published: March 2023

Abstract
Activating mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase domain determine responsiveness to EGFR tyrosine kinase inhibitors in patients with advanced non–small cell lung cancer (NSCLC). The modulation of transcriptional pathways by mutant EGFR signaling is not fully understood. Previously, we and others identified a single base pair change leading to a threonine to methionine (T790M) amino acid alteration in the ATP-binding pocket of the EGFR as a common mechanism of acquired resistance. The gefitinib-resistant, T790M-mutant H1975 NSCLC cell line undergoes prominent growth arrest and apoptosis when treated with the irreversible EGFR inhibitor, CL-387,785. We did a transcriptional profiling study of mutant EGFR target genes that are differentially expressed in the “resistant” gefitinib-treated and the “sensitive” CL387,785-treated H1975 cells to identify the pivotal transcriptional changes in NSCLC with EGFR-activating mutations. We identified a small subset of early gene changes, including significant reduction of cyclin D1 as a result of EGFR inhibition by CL-387,785 but not by gefitinib. The reduction in cyclin D1 transcription was associated with subsequent suppression of E2F-responsive genes, consistent with proliferation arrest. Furthermore, cyclin D1 expression was higher in EGFR-mutant lung cancer cells compared with cells with wild-type EGFR. EGFR-mutant cells were routinely sensitive to the cyclin-dependent kinase inhibitor flavopiridol, confirming the functional relevance of the cyclin D axis. These studies suggest that cyclin D1 may contribute to the emergence of EGFR-driven tumorigenesis and can be an alternative target of therapy. (Cancer Res 2006; 66(23): 11389-98)
Data from Vascular Proliferation Is Important for Clinical Progress of Endometrial Cancer
Authors: Stefansson Ingunn M. , Salvesen Helga B. , Akslen Lars A.
Published: March 2023

Abstract
Angiogenesis is essential for tumor growth, invasion, and metastatic spread. Whereas microvessel density (MVD) has been widely used as a measure of tumor-associated angiogenesis, we now wanted to examine the significance of other angiogenic markers, especially vascular proliferation (by Ki-67/factor VIII staining) and the degree of pericyte coverage [by α-smooth muscle actin (α-SMA)/factor VIII staining], in a large and population-based series of endometrial carcinoma with complete follow-up. Due to limited information on the role of lymphangiogenesis in these tumors, lymphatic vessel density (LVD) by LYVE-1 staining was also determined, as well as selected angiogenic factors [vascular endothelial growth factor (VEGF)-A, VEGF-C, VEGF-D and basic fibroblast growth factor (bFGF)], which could possibly be related to vascular proliferation and lymphangiogenesis. The information on angiogenic phenotype was related to clinicopathologic features and disease progress. Median vascular proliferation, as estimated by vascular proliferation index (VPI), was 3.9% and high VPI was associated with features of aggressive tumors and decreased survival. The prognostic effect of VPI was superior to that of MVD. Presence of pericyte coverage, as estimated by the α-SMA index (SMAI), was 35% and low SMAI was significantly associated with vascular invasion by tumor cells and impaired prognosis. Peritumoral lymphatic vessels (LVD-pt) were found in 39.5% of the cases and high LVD-pt was significantly associated with aggressive tumor features and decreased survival. In multivariate survival analysis, only the extent of vascular proliferation had independent prognostic effect, in addition to well-known clinicopathologic factors, whereas MVD did not have significant prognostic value. In conclusion, our study indicates that vascular proliferation is a meaningful variable in assessing the angiogenic phenotype of endometrial carcinoma. (Cancer Res 2006; 66(6): 3303-9)
Data from Tagging Single-Nucleotide Polymorphisms in Antioxidant Defense Enzymes and Susceptibility to Breast Cancer
Authors: Cebrian Arancha , Pharoah Paul D. , Ahmed Shahana , Smith Paula L. , Luccarini Craig , Luben Robert , Redman Karen , Munday Hannah , Easton Douglas F. , Dunning Alison M. , Ponder Bruce A.J.
Published: March 2023

Abstract
It is generally believed that the initiation of breast cancer is a consequence of cumulative genetic damage leading to genetic alterations and provoking uncontrolled cellular proliferation and/or aberrant programmed cell death, or apoptosis. Reactive oxygen species have been related to the etiology of cancer as they are known to be mitogenic and therefore capable of tumor promotion. The aim of this study was to assess the role of common variation in 10 polymorphic genes coding for antioxidant defense enzymes in modulating individual susceptibility to breast cancer using a case-control study (N cases = 4,474 and N controls = 4,580). Both cases and controls were from the East Anglian region of the United Kingdom. We have identified a set of 54 single nucleotide polymorphisms (SNPs) that efficiently tag all the known SNPs in the 10 genes and are also expected to tag any unknown SNPs in each gene. We found no evidence for association of common variants in SOD1, SOD2, GPX1, GPX4, GSR, TXNRD1, and TXN2. There was borderline evidence for association of variants in CAT g27168a {P [2 degrees of freedom (df)] = 0.05}, TXN t2715c [P (2 df) = 0.007], and TXNRD2 A66S and TXNRD2 g23524a (Ptrend = 0.074 and 0.046, respectively). For TXNRD2 A66S [AS versus AA: odds ratio (OR), 1.05; 95% confidence intervals (95% CI), 0.96-1.15; SS versus AA: OR, 1.12; 95% CI, 0.98-1.29], there are bioinformatics data to suggest that it is functional but confirmation in independent data sets is required before they can be regarded as definitive breast cancer susceptibility alleles. Even if confirmed, these four alleles would account for just 0.32% of the excess familial risk of breast cancer. (Cancer Res 2006; 66(2): 1225-33)
Data from Mitochondrial Genetic Background Modifies Breast Cancer Risk
Authors: Bai Ren-Kui , Leal Suzanne M. , Covarrubias Daniel , Liu Aiyi , Wong Lee-Jun C.
Published: March 2023

Abstract
Inefficient mitochondrial electron transport chain (ETC) function has been implicated in the vicious cycle of reactive oxygen species (ROS) production that may predispose an individual to late onset diseases, such as diabetes, hypertension, and cancer. Mitochondrial DNA (mtDNA) variations may affect the efficiency of ETC and ROS production, thus contributing to cancer risk. To test this hypothesis, we genotyped 69 mtDNA variations in 156 unrelated European-American females with familial breast cancer and 260 age-matched European-American female controls. Fisher's exact test was done for each single-nucleotide polymorphism (SNP)/haplogroup and the P values were adjusted for multiple testing using permutation. Odds ratio (OR) and its 95% confidence interval (95% CI) were calculated using the Sheehe correction. Among the 69 variations, 29 were detected in the study subjects. Three SNPs, G9055A (OR, 3.03; 95% CI, 1.63–5.63; P = 0.0004, adjusted P = 0.0057), A10398G (OR, 1.79; 95% CI, 1.14–2.81; P = 0.01, adjusted P = 0.19), and T16519C (OR, 1.98; 95% CI, 1.25–3.12; P = 0.0030, adjusted P = 0.0366), were found to increase breast cancer risk; whereas T3197C (OR, 0.31; 95% CI, 0.13–0.75; P = 0.0043, adjusted P = 0.0526) and G13708A (OR, 0.47; 95% CI, 0.24–0.92; P = 0.022, adjusted P = 0.267) were found to decrease breast cancer risk. Overall, individuals classified as haplogroup K show a significant increase in the risk of developing breast cancer (OR, 3.03; 95% CI, 1.63–5.63; P = 0.0004, adjusted P = 0.0057), whereas individuals bearing haplogroup U have a significant decrease in breast cancer risk (OR, 0.37; 95% CI, 0.19–0.73; P = 0.0023, adjusted P = 0.03). Our results suggest that mitochondrial genetic background plays a role in modifying an individual's risk to breast cancer. [Cancer Res 2007;67(10):4687–94]
Data from NKX3.1 Homeodomain Protein Binds to Topoisomerase I and Enhances Its Activity
Authors: Bowen Cai , Stuart August , Ju Jeong-Ho , Tuan Jenny , Blonder Josip , Conrads Thomas P. , Veenstra Timothy D. , Gelmann Edward P.
Published: March 2023

Abstract
The prostate-specific homeodomain protein NKX3.1 is a tumor suppressor that is commonly down-regulated in human prostate cancer. Using an NKX3.1 affinity column, we isolated topoisomerase I (Topo I) from a PC-3 prostate cancer cell extract. Topo I is a class 1B DNA-resolving enzyme that is ubiquitously expressed in higher organisms and many prokaryotes. NKX3.1 interacts with Topo I to enhance formation of the Topo I-DNA complex and to increase Topo I cleavage of DNA. The two proteins interacted in affinity pull-down experiments in the presence of either DNase or RNase. The NKX3.1 homeodomain was essential, but not sufficient, for the interaction with Topo I. NKX3.1 binding to Topo I occurred independently of the Topo I NH2-terminal domain. The binding of equimolar amounts of Topo I to NKX3.1 caused displacement of NKX3.1 from its cognate DNA recognition sequence. Topo I activity in prostates of Nkx3.1+/− and Nkx3.1−/− mice was reduced compared with wild-type mice, whereas Topo I activity in livers, where no NKX3.1 is expressed, was independent of Nkx3.1 genotype. Endogenous Topo I and NKX3.1 could be coimmunoprecipitated from LNCaP cells, where NKX3.1 and Topo I were found to colocalize in the nucleus and comigrate within the nucleus in response to either γ-irradiation or mitomycin C exposure, two DNA-damaging agents. This is the first report that a homeodomain protein can modify the activity of Topo I and may have implications for organ-specific DNA replication, transcription, or DNA repair. [Cancer Res 2007;67(2):455–64]
Data from Oncogenic BRAF Is Required for Tumor Growth and Maintenance in Melanoma Models
Authors: Hoeflich Klaus P. , Gray Daniel C. , Eby Michael T. , Tien Janet Y. , Wong Leo , Bower Janeko , Gogineni Alvin , Zha Jiping , Cole Mary J. , Stern Howard M. , Murray Lesley J. , Davis David P. , Seshagiri Somasekar
Published: March 2023

Abstract
The usual paradigm for developing kinase inhibitors in oncology is to use a high-affinity proof-of-concept inhibitor with acceptable metabolic properties for key target validation experiments. This approach requires substantial medicinal chemistry and can be confounded by drug toxicity and off-target activities of the test molecule. As a better alternative, we have developed inducible short-hairpin RNA xenograft models to examine the in vivo efficacy of inhibiting oncogenic BRAF. Our results show that tumor regression resulting from BRAF suppression is inducible, reversible, and tightly regulated in these models. Analysis of regressing tumors showed the primary mechanism of action for BRAF to be increased tumor cell proliferation and survival. In a metastatic melanoma model, conditional BRAF suppression slowed systemic tumor growth as determined by in vivo bioluminescence imaging. Taken together, gain-of-function BRAF signaling is strongly associated with in vivo tumorigenicity, confirming BRAF as an important target for small-molecule and RNA interference–based therapeutics. (Cancer Res 2006; 66(2): 999-1006)
Data from Methylation-Independent Silencing of the Tumor Suppressor INK4b (p15) by CBFβ-SMMHC in Acute Myelogenous Leukemia with inv(16)
Authors: Markus Jan , Garin Matthew T. , Bies Juraj , Galili Naomi , Raza Azra , Thirman Michael J. , Le Beau Michelle M. , Rowley Janet D. , Liu P. Paul , Wolff Linda
Published: March 2023

Abstract
The tumor suppressor gene INK4b (p15) is silenced by CpG island hypermethylation in most acute myelogenous leukemias (AML), and this epigenetic phenomenon can be reversed by treatment with hypomethylating agents. Thus far, it was not investigated whether INK4b is hypermethylated in all cytogenetic subtypes of AML. A comparison of levels of INK4b methylation in AML with the three most common cytogenetic alterations, inv(16), t(8;21), and t(15;17), revealed a strikingly low level of methylation in all leukemias with inv(16) compared with the other types. Surprisingly, the expression level of INK4b in inv(16)+ AML samples was low and comparable with that of the other subtypes. An investigation into an alternative mechanism of INK4b silencing determined that the loss of INK4b expression was caused by inv(16)-encoded core binding factor β-smooth muscle myosin heavy chain (CBFβ-SMMHC). The silencing was manifested in an inability to activate the normal expression of INK4b RNA as shown in vitamin D3–treated U937 cells expressing CBFβ-SMMHC. CBFβ-SMMHC was shown to displace RUNX1 from a newly determined CBF site in the promoter of INK4b. Importantly, this study (a) establishes that the gene encoding the tumor suppressor p15INK4b is a target of CBFβ-SMMHC, a finding relevant to the leukemogenesis process, and (b) indicates that, in patients with inv(16)-containing AML, reexpression from the INK4b locus in the leukemia would not be predicted to occur using hypomethylating drugs. [Cancer Res 2007;67(3):992–1000]
Data from Expression of p16Ink4a Compensates for p18Ink4c Loss in Cyclin-Dependent Kinase 4/6–Dependent Tumors and Tissues
Authors: Ramsey Matthew R. , Krishnamurthy Janakiraman , Pei Xin-Hai , Torrice Chad , Lin Weili , Carrasco Daniel R. , Ligon Keith L. , Xiong Yue , Sharpless Norman E.
Published: March 2023

Abstract
Cell cycle progression from G1 to S phase depends on phosphorylation of pRb by complexes containing a cyclin (D type or E type) and cyclin-dependent kinase (e.g., cdk2, cdk4, or cdk6). Ink4 proteins function to oppose the action of cdk4/6-cyclin D complexes by inhibiting cdk4/6. We employed genetic and pharmacologic approaches to study the interplay among Ink4 proteins and cdk4/6 activity in vivo. Mouse embryo fibroblasts (MEF) lacking p16Ink4a and p18Ink4c showed similar growth kinetics as wild-type MEFs despite increased cdk4 activity. In vivo, germline deficiency of p16Ink4a and p18Ink4c resulted in increased proliferation in the intermediate pituitary and pancreatic islets of adult mice, and survival of p16Ink4a−/−;p18Ink4c−/− mice was significantly reduced due to aggressive pituitary tumors. Compensation among the Ink4 proteins was observed both in vivo in p18Ink4c−/− mice and in MEFs from p16Ink4a−/−, p18Ink4c−/−, or p16Ink4a−/−;p18Ink4c−/− mice. Treatment with PD 0332991, a specific cdk4/6 kinase inhibitor, abrogated proliferation in those compartments where Ink4 deficiency was associated with enhanced proliferation (i.e., islets, pituitary, and B lymphocytes) but had no effect on proliferation in other tissues such as the small bowel. These data suggest that p16Ink4a and p18Ink4c coordinately regulate the in vivo catalytic activity of cdk4/6 in specific compartments of adult mice. [Cancer Res 2007;67(10):4732–41]
Data from Functional Gene Expression Analysis Uncovers Phenotypic Switch in Aggressive Uveal Melanomas
Authors: Onken Michael D. , Ehlers Justis P. , Worley Lori A. , Makita Jun , Yokota Yoshifumi , Harbour J. William
Published: March 2023

Abstract
Microarray gene expression profiling is a powerful tool for generating molecular cancer classifications. However, elucidating biological insights from these large data sets has been challenging. Previously, we identified a gene expression-based classification of primary uveal melanomas that accurately predicts metastatic death. Class 1 tumors have a low risk and class 2 tumors a high risk for metastatic death. Here, we used genes that discriminate these tumor classes to identify biological correlates of the aggressive class 2 signature. A search for Gene Ontology categories enriched in our class-discriminating gene list revealed a global down-regulation of neural crest and melanocyte-specific genes and an up-regulation of epithelial genes in class 2 tumors. Correspondingly, class 2 tumors exhibited epithelial features, such as polygonal cell morphology, up-regulation of the epithelial adhesion molecule E-cadherin, colocalization of E-cadherin and β-catenin to the plasma membrane, and formation of cell-cell adhesions and acinar structures. One of our top class-discriminating genes was the helix-loop-helix inhibitor ID2, which was strongly down-regulated in class 2 tumors. The class 2 phenotype could be recapitulated by eliminating Id2 in cultured class 1 human uveal melanoma cells and in a mouse ocular melanoma model. Id2 seemed to suppress the epithelial-like class 2 phenotype by inhibiting an activator of the E-cadherin promoter. Consequently, Id2 loss triggered up-regulation of E-cadherin, which in turn promoted anchorage-independent cell growth, a likely antecedent to metastasis. These findings reveal new roles for Id2 and E-cadherin in uveal melanoma progression, and they identify potential targets for therapeutic intervention. (Cancer Res 2006; 66(9): 4602-9)
Data from Signal Transducer and Activator of Transcription 3 Is Required for the Oncogenic Effects of Non–Small-Cell Lung Cancer–Associated Mutations of the Epidermal Growth Factor Receptor
Authors: Alvarez James V. , Greulich Heidi , Sellers William R. , Meyerson Matthew , Frank David A.
Published: March 2023

Abstract
Somatic mutations in the epidermal growth factor receptor (EGFR) occur frequently in lung cancer and confer sensitivity to EGFR kinase inhibitors gefitinib and erlotinib. These mutations, which occur in the kinase domain of the protein, also render EGFR constitutively active and transforming. Signal transducers and activators of transcription 3 (STAT3) transduces signals from a number of oncogenic tyrosine kinases and contributes to a wide spectrum of human malignancies. Here, we show that STAT3 is activated by mutant EGFRs and is necessary for its downstream phenotypic effects. Inhibiting STAT3 function in fibroblasts abrogates transformation by mutant EGFR. In non–small-cell lung cancer cells, STAT3 activity is regulated by EGFR through modulation of STAT3 serine phosphorylation. Inhibiting STAT3 function increases apoptosis of these cells, suggesting that STAT3 is necessary for their survival. Finally, a group of genes constituting a STAT3 signature is enriched in lung tumors with EGFR mutations. Thus, STAT3 is a critical mediator of the oncogenic effects of somatic EGFR mutations and targeting STAT3 may be an effective strategy for treating tumors characterized by these mutations. (Cancer Res 2006; 66(6): 3162-8)
Data from N-Cadherin Signaling Potentiates Mammary Tumor Metastasis via Enhanced Extracellular Signal-Regulated Kinase Activation
Authors: Hulit James , Suyama Kimita , Chung Su , Keren Rinat , Agiostratidou Georgia , Shan Weisong , Dong Xinyuan , Williams Terence M. , Lisanti Michael P. , Knudsen Karen , Hazan Rachel B.
Published: March 2023

Abstract
N-cadherin is up-regulated in aggressive breast carcinomas, but its mechanism of action in vivo remains unknown. Transgenic mice coexpressing N-cadherin and polyomavirus middle T antigen (PyVmT) in the mammary epithelium displayed increased pulmonary metastasis, with no differences in tumor onset or growth relative to control PyVmT mice. PyVmT-N-cadherin tumors contained higher levels of phosphorylated extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) than PyVmT controls, and phosphorylated ERK staining was further increased in pulmonary metastases. Tumor cell isolates from PyVmT-N-cadherin mice exhibited enhanced ERK activation, motility, invasion, and matrix metalloproteinase-9 (MMP-9) expression relative to PyVmT controls. MAPK/ERK kinase 1 inhibition in PyVmT-N-cadherin cells reduced MMP-9 production and invasion but not motility. Furthermore, inactivation of fibroblast growth factor receptor in PyVmT-N-cadherin cells reduced motility, invasion, and ERK activation but had no effect on PyVmT cells. Thus, de novo expression of N-cadherin in mammary ducts enhances metastasis of breast tumors via enhanced ERK signaling. [Cancer Res 2007;67(7):3106–16]
Data from Distinct Genetic Signatures among Pilocytic Astrocytomas Relate to Their Brain Region Origin
Authors: Sharma Mukesh K. , Mansur David B. , Reifenberger Guido , Perry Arie , Leonard Jeffrey R. , Aldape Kenneth D. , Albin Meredith G. , Emnett Ryan J. , Loeser Simon , Watson Mark A. , Nagarajan Rakesh , Gutmann David H.
Published: March 2023

Abstract
Pilocytic astrocytomas (PAs) are the most common glioma in children. Whereas many PAs are slow-growing or clinically indolent, others exhibit more aggressive features with tumor recurrence and death. To identify genetic signatures that might predict PA clinical behavior, we did gene expression profiling on 41 primary PAs arising sporadically and in patients with neurofibromatosis type 1 (NF1). Whereas no expression signature was found that could discriminate clinically aggressive or recurrent tumors from more indolent cases, PAs arising in patients with NF1 did exhibit a unique gene expression pattern. In addition, we identified a gene expression signature that stratified PAs by location (supratentorial versus infratentorial). Lastly, we also identified a gene expression pattern common to PAs and normal mouse astrocytes and neural stem cells from these distinct brain regions as well as a gene expression pattern shared between PAs and another human glial tumor (ependymoma) arising supratentorially compared with those originating in the posterior fossa. These results suggest that glial tumors share an intrinsic, lineage-specific molecular signature that reflects the brain region in which their nonmalignant predecessors originated. [Cancer Res 2007;67(3):890–900]
Data from Influence of Bcl-2 Family Members on the Cellular Response of Small-Cell Lung Cancer Cell Lines to ABT-737
Authors: Tahir Stephen K. , Yang Xiufen , Anderson Mark G. , Morgan-Lappe Susan E. , Sarthy Aparna V. , Chen Jun , Warner Robert B. , Ng Shi-Chung , Fesik Stephen W. , Elmore Steve W. , Rosenberg Saul H. , Tse Christin
Published: March 2023

Abstract
ABT-737 is a novel and potent Bcl-2 antagonist with single-agent activity against small-cell lung cancer (SCLC) cell lines. Here, we evaluated the contribution of Bcl-2 family members to the in vitro cellular response of several SCLC cell lines to ABT-737. Relatively higher levels of Bcl-2, Bcl-XL, Bim and Noxa, and lower levels of Mcl-1 characterized naïve SCLC cell lines that were sensitive to ABT-737. Conversely, a progressive decrease in the relative levels of Bcl-2 and Noxa and a progressive increase in Mcl-1 levels characterized the increased resistance of H146 cells following chronic exposure to ABT-737. Knockdown of Mcl-1 with small interfering RNA sensitized two resistant SCLC cell lines H196 and DMS114 to ABT-737 by enhancing the induction of apoptosis. Likewise, up-regulation of Noxa sensitized H196 cells to ABT-737. Combination treatment with DNA-damaging agents was extremely synergistic with ABT-737 and was associated with the down-regulation of Mcl-1 and the up-regulation of Noxa, Puma, and Bim in H196 cells. Thus, SCLC cells sensitive to ABT-737 expressed the target proteins Bcl-2 and Bcl-XL, whereas Mcl-1 and factors regulating Mcl-1 function seem to contribute to the overall resistance of SCLC cells to ABT-737. Overall, these observations provide further insight as to the mechanistic bases for ABT-737 efficacy in SCLC and will be helpful for profiling patients and aiding in the rational design of combination therapies. [Cancer Res 2007;67(3):1176–83]
Data from 15-Deoxy-Δ12,14-Prostaglandin J2 Inhibits Transcriptional Activity of Estrogen Receptor-α via Covalent Modification of DNA-Binding Domain
Authors: Kim Han-Jong , Kim Joon-Young , Meng Zhaojing , Wang Li Hua , Liu Fa , Conrads Thomas P. , Burke Terrence R. , Veenstra Timothy D. , Farrar William L.
Published: March 2023

Abstract
The cyclopentenone 15-deoxy-Δ12,14-prostaglandin J2 (15d-PGJ2) inhibits proliferation of cancer cells, including breast cancers, by peroxisome proliferator-activated receptor-γ (PPARγ)–dependent and PPARγ-independent mechanisms. However, little is known about its effect on the transcriptional activity of estrogen receptor-α (ERα) that plays vital roles in the growth of breast cancers. Here, we show that 15d-PGJ2 inhibits both 17β-estradiol (E2)–dependent and E2-independent ERα transcriptional activity by PPARγ-independent mechanism. In addition, 15d-PGJ2 directly modifies ERα protein via its reactive cyclopentenone moiety, evidenced by incorporation of biotinylated 15d-PGJ2 into ERα, both in vitro and in vivo. Nanoflow reverse-phase liquid chromatography tandem mass spectrometry analysis identifies two cysteines (Cys227 and Cys240) within the COOH-terminal zinc finger of ERα DNA-binding domain (DBD) as targets for covalent modification by 15d-PGJ2. Gel mobility shift and chromatin immunoprecipitation assays show that 15d-PGJ2 inhibits DNA binding of ERα and subsequent repression of ERα target gene expression, such as pS2 and c-Myc. Therefore, our results suggest that 15d-PGJ2 can block ERα function by covalent modification of cysteine residues within the vulnerable COOH-terminal zinc finger of ERα DBD, resulting in fundamental inhibition of both hormone-dependent and hormone-independent ERα transcriptional activity. [Cancer Res 2007;67(6):2595–602]
Data from Combined cDNA Array Comparative Genomic Hybridization and Serial Analysis of Gene Expression Analysis of Breast Tumor Progression
Authors: Yao Jun , Weremowicz Stanislawa , Feng Bin , Gentleman Robert C. , Marks Jeffrey R. , Gelman Rebecca , Brennan Cameron , Polyak Kornelia
Published: March 2023

Abstract
To identify genetic changes involved in the progression of breast carcinoma, we did cDNA array comparative genomic hybridization (CGH) on a panel of breast tumors, including 10 ductal carcinoma in situ (DCIS), 18 invasive breast carcinomas, and two lymph node metastases. We identified 49 minimal commonly amplified regions (MCRs) that included known (1q, 8q24, 11q13, 17q21-q23, and 20q13) and several uncharacterized (12p13 and 16p13) regional copy number gains. With the exception of the 17q21 (ERBB2) amplicon, the overall frequency of copy number alterations was higher in invasive tumors than that in DCIS, with several of them present only in invasive cancer. Amplification of candidate loci was confirmed by quantitative PCR in breast carcinomas and cell lines. To identify putative targets of amplicons, we developed a method combining array CGH and serial analysis of gene expression (SAGE) data to correlate copy number and expression levels for each gene within MCRs. Using this approach, we were able to distinguish a few candidate targets from a set of coamplified genes. Analysis of the 12p13-p12 amplicon identified four putative targets: TEL/ETV6, H2AFJ, EPS8, and KRAS2. The amplification of all four candidates was confirmed by quantitative PCR and fluorescence in situ hybridization, but only H2AFJ and EPS8 were overexpressed in breast tumors with 12p13 amplification compared with a panel of normal mammary epithelial cells. These results show the power of combined array CGH and SAGE analysis for the identification of candidate amplicon targets and identify H2AFJ and EPS8 as novel putative oncogenes in breast cancer. (Cancer Res 2006; 66(8): 4065-78)
Data from Cellular FLICE-Inhibitory Protein Down-regulation Contributes to Celecoxib-Induced Apoptosis in Human Lung Cancer Cells
Authors: Liu Xiangguo , Yue Ping , Schönthal Axel H. , Khuri Fadlo R. , Sun Shi-Yong
Published: March 2023

Abstract
The cyclooxygenase-2 (COX-2) inhibitor celecoxib is an approved drug in the clinic for colon cancer chemoprevention and has been tested for its chemopreventive and therapeutic efficacy in various clinical trials. Celecoxib induces apoptosis in a variety of human cancer cells including lung cancer cells. Our previous work has shown that celecoxib induces death receptor 5 expression, resulting in induction of apoptosis and enhancement of tumor necrosis factor–related apoptosis-inducing ligand (TRAIL)–induced apoptosis in human lung cancer cells. In the current study, we further show that celecoxib down-regulated the expression of cellular FLICE-inhibitory protein (c-FLIP), a major negative regulator of the death receptor–mediated extrinsic apoptotic pathway, through a ubiquitin/proteasome–dependent mechanism independent of COX-2 in human lung cancer cells. Overexpression of c-FLIP, particularly FLIPL, inhibited not only celecoxib-induced apoptosis but also apoptosis induced by the combination of celecoxib and TRAIL. These results thus indicate that c-FLIP down-regulation also contributes to celecoxib-induced apoptosis and enhancement of TRAIL-induced apoptosis, which complements our previous finding that the extrinsic apoptotic pathway plays a critical role in celecoxib-induced apoptosis in human lung cancer cells. Collectively, we conclude that celecoxib induces apoptosis in human lung cancer cells through activation of the extrinsic apoptotic pathway, primarily by induction of death receptor 5 and down-regulation of c-FLIP. (Cancer Res 2006; 66(23): 11115-9)
Data from Inhibition of Histone Deacetylation Does Not Block Resilencing of p16 after 5-Aza-2′-Deoxycytidine Treatment
Authors: Egger Gerda , Aparicio Ana M. , Escobar Sonia G. , Jones Peter A.
Published: March 2023

Abstract
Epigenetic drugs are in use in clinical trials of various human cancers and are potent at reactivating genes silenced by DNA methylation and chromatin modifications. We report here the analysis of a set of normal fibroblast and cancer cell lines after combination treatment with the DNA methyltransferase inhibitor 5-aza-2′-deoxycytidine (5-aza-CdR) and the histone deacetylase inhibitor 4-phenylbutyric acid (PBA). Low doses of the drug combination caused cell cycle arrest, whereas high doses induced apoptosis in T24 bladder carcinoma cells. Both p16 (CDKN2A/INK4) and p21 (CIP1/SDI1/WAF1) expression were induced to similar levels in normal and cancer cells in a dose-dependent fashion after combination treatments. We detected a distinct increase of histone H3 acetylation at lysine 9/14 near the transcription start sites, in both LD419 normal fibroblasts and T24 bladder carcinoma cells, whereas the acetylation changes in the p21 locus were less apparent. Interestingly, the levels of trimethylation of histone H3 on lysine 9, which usually marks inactive chromatin regions and was associated with the p16 promoter in silenced T24 cells, did not change after drug treatments. Furthermore, we provide evidence that the remethylation of the p16 promoter CpG island in T24 cells after 5-aza-CdR treatment cannot be halted by subsequent continuous PBA treatment. The p16 gene is resilenced with kinetics similar to 5-aza-CdR only–treated cells, which is also marked by a localized loss of histone acetylation at the transcription start site. Altogether, our data provide new insights into the mechanism of epigenetic drugs and have important implications for epigenetic therapy. [Cancer Res 2007;67(1):346–53]
Data from Tumor-Induced Activation of Lymphatic Endothelial Cells via Vascular Endothelial Growth Factor Receptor-2 Is Critical for Prostate Cancer Lymphatic Metastasis
Authors: Zeng Yiping , Opeskin Kenneth , Goad Jeremy , Williams Elizabeth D.
Published: March 2023

Abstract
Prostate cancer disseminates initially and primarily to regional lymph nodes. However, the nature of interactions between tumor cells and lymphatic endothelial cells (LEC) is poorly understood. In the current study, we have isolated prostate LECs and developed a series of two-dimensional and three-dimensional in vitro coculture systems and in vivo orthotopic prostate cancer models to investigate the interactions of prostate cancer cells with prostate LECs. In vitro, highly lymph node metastatic prostate cancer cell lines (PC-3 and LNCaP) and their conditioned medium enhanced prostate LEC tube formation and migration, whereas poorly lymph node metastatic prostate cancer cells (DU145) or normal prostate epithelial cells (RWPE-1) or their conditioned medium had no effect. In vivo, the occurrence of lymphatic invasion and lymph node metastasis was observed in PC-3 and LNCaP xenografts but not in DU145 xenografts. Furthermore, vascular endothelial growth factor (VEGF) receptor (VEGFR)-2 is expressed by prostate LECs, and its ligands VEGF-A, VEGF-C, and VEGF-D are up-regulated in highly lymph node metastatic prostate cancer cells. Recombinant VEGF-A and VEGF-C, but not VEGF-C156S, potently promoted prostate LEC tube formation, migration, and proliferation in vitro, indicating that signaling via VEGFR-2 rather than VEGFR-3 is involved in these responses. Consistent with this, blockade of VEGFR-2 significantly reduced tumor-induced activation of LECs. These results show that the interaction of prostate tumor cells with LECs via VEGFR-2 modulates LEC behavior and is related to the ability of tumor cells to form lymph node metastases. (Cancer Res 2006; 66(19): 9566-75)
Data from Transactivation of the Epidermal Growth Factor Receptor by Formylpeptide Receptor Exacerbates the Malignant Behavior of Human Glioblastoma Cells
Authors: Huang Jian , Hu Jinyue , Bian Xiuwu , Chen Keqiang , Gong Wanghua , Dunlop Nancy M. , Howard O.M. Zack , Wang Ji Ming
Published: March 2023

Abstract
The G protein-coupled formylpeptide receptor (FPR), which mediates leukocyte migration in response to bacterial and host-derived chemotactic peptides, promotes the chemotaxis, survival, and tumorigenesis of highly malignant human glioblastoma cells. Because glioblastoma cells may also express other receptors for growth signals, such as the epidermal growth factor (EGF) receptor (EGFR), we investigated the role of EGFR in the signaling cascade of FPR and how two receptors cross-talk to exacerbate tumor growth. We found that N-formyl-methionyl-leucyl-phenylalanine, an FPR agonist peptide, rapidly induced EGFR phosphorylation at tyrosine residue (Tyr) 992, but not residues 846, 1068, or 1173, in glioblastoma cells, whereas all these residues were phosphorylated after only EGF treatment. The FPR agonist-induced EGFR phosphorylation in tumor cells was dependent on the presence of FPR as well as Gαi proteins, and was controlled by Src tyrosine kinase. The transactivation of EGFR contributes to the biological function of FPR in glioblastoma cells because inhibition of EGFR phosphorylation significantly reduced FPR agonist-induced tumor cell chemotaxis and proliferation. Furthermore, depletion of both FPR and EGFR by short interference RNA abolished the tumorigenesis of the glioblastoma cells. Our study indicates that the glioblastoma-promoting activity of FPR is mediated in part by transactivation of EGFR and the cross-talk between two receptors exacerbates the malignant phenotype of tumor cells. Thus, targeting both receptors may yield antiglioblastoma agents superior to those targeting one of them. [Cancer Res 2007;67(12):5906–13]
Data from The Soluble Wnt Receptor Frizzled8CRD-hFc Inhibits the Growth of Teratocarcinomas In vivo
Authors: DeAlmeida Venita I. , Miao Li , Ernst James A. , Koeppen Hartmut , Polakis Paul , Rubinfeld Bonnee
Published: March 2023

Abstract
Wnt signaling is important for normal cell proliferation and differentiation, and mutations in pathway components are associated with human cancers. Recent studies suggest that altered wnt ligand/receptor interactions might also contribute to human tumorigenesis. Therefore, agents that antagonize wnt signaling at the extracellular level would be attractive therapeutics for these cancers. We have generated a soluble wnt receptor comprising the Frizzled8 cysteine-rich domain (CRD) fused to the human Fc domain (F8CRDhFc) that exhibits favorable pharmacologic properties in vivo. Potent antitumor efficacy was shown using the mouse mammary tumor virus-Wnt1 tumor model under dosing conditions that did not produce detectable toxicity in regenerating tissue compartments. In vitro, F8CRDhFc inhibited autocrine wnt signaling in the teratoma cell lines PA-1, NTera-2, Tera-2, and NCCIT. In vivo, systemic administration of F8CRDhFc significantly retarded the growth of tumor xenografts derived from two of these cell lines, PA-1 and NTera-2. Pharmacodynamic markers of wnt signaling, identified by gene expression analysis of cultured teratoma cells, were also modulated in the tumor xenografts following treatment with F8CRDhFc. Additionally, these markers could be used as indicators of treatment efficacy and might also be useful in identifying patients that would benefit from the therapeutic agent. This is the first report showing the efficacy of a soluble wnt receptor as an antitumor agent and suggests that further development of wnt antagonists will have utility in treating human cancer. [Cancer Res 2007;67(11):5371–9]
Data from Elevated Expression of the Oncogene c-fms and Its Ligand, the Macrophage Colony-Stimulating Factor-1, in Cervical Cancer and the Role of Transforming Growth Factor-β1 in Inducing c-fms Expression
Authors: Kirma Nameer , Hammes Luciano S. , Liu Ya-Guang , Nair Hareesh B. , Valente Philip T. , Kumar Shantha , Flowers Lisa C. , Tekmal Rajeshwar Rao
Published: March 2023

Abstract
Cervical cancer is the third most common gynecologic cancer in the United States. The presence and possible involvement of several cytokines have been studied in cervical cancer; however, very little data, if any, are available on whether cervical tumors are responsive to stimulation by the macrophage colony-stimulating factor-1 (CSF-1). Given the involvement of c-fms and its ligand CSF-1 in gynecologic cancers, such as that of the uterus and the ovaries, we have examined the expression of c-fms and CSF-1 in cervical tumor (n = 17) and normal cervix (n = 8) samples. The data show that c-fms and its ligand are significantly higher in cervical carcinomas compared with normal samples. Immunohistochemistry not only showed that tumor cells expressed significantly higher levels of c-fms but also c-fms levels were markedly higher in tumor cells than tumor-associated stromal cells. Blocking c-fms activity in cervical cancer cells, which express CSF-1 and c-fms, resulted in increased apoptosis and decreased motility compared with control, suggesting that CSF-1/c-fms signaling may be involved in enhanced survival and possibly invasion by cervical cancer cells via an autocrine mechanism. Combined, the data show for the first time the induction of CSF-1 and c-fms in cervical carcinomas and suggest that c-fms activation may play a role in cervical carcinogenesis. Additionally, our data suggest that transforming growth factor-β1 may be a factor in inducing the expression of c-fms in cervical cancer cells. The data suggest that c-fms may be a valuable therapeutic target in cervical cancer. [Cancer Res 2007;67(5):1918–26]
Data from Human Papillomavirus 16/18 E6 Oncoprotein Is Expressed in Lung Cancer and Related with p53 Inactivation
Authors: Cheng Ya-Wen , Wu Ming-Fang , Wang John , Yeh Kun-Tu , Goan Yih-Gang , Chiou Hui-Ling , Chen Chih-Yi , Lee Huei
Published: March 2023

Abstract
Inactivation of p53 by human papillomavirus 16/18 E6 plays a crucial role in cervical tumorigenesis. To investigate the involvement of HPV16/18 in lung tumorigenesis, the association between HPV16 or HPV18 E6 and p53 protein expression in 122 lung tumors was evaluated by immunohistochemistry, and data showed that HPV16/18 E6 expression correlated inversely with p53 expression, which was further confirmed by tissue in situ immunostaining. Real-time reverse transcription-PCR analysis indicated that E6-positive tumors had lower p21WAF1/CIP1 and mdm2 mRNA levels than E6-negative tumors. To elucidate the role of E6 in p53 inactivation, we successfully established lung adenocarcinoma cell lines with or without HPV16 infection from patients' pleural effusions. Western blotting showed that E6 protein was indeed expressed in HPV16-infected cells and a lower level of p53 protein was observed in E6-positive cells compared with E6-negative cells. Moreover, the levels of p21WAF1/CIP1 and mdm2 mRNA in E6-positive cells were lower than in E6-negative cells. The interaction of E6 with p53 protein was revealed by immunoprecipitation assay showing that p53 could be inactivated by E6 protein. Conversely, p53 proteins and p21WAF1/CIP1 and mdm2 mRNA expressions were restored in E6-knockdown cells by RNA interference compared with control cells. These results reveal that HPV16/18 E6 may be partially involved in p53 inactivation to down-regulate p21WAF1/CIP1 and mdm2 transcription. In conclusion, HPV16/18 E6 is indeed expressed in HPV DNA–positive lung tumors and is involved in p53 inactivation to contributing to HPV-mediated lung tumorigenesis. [Cancer Res 2007;67(22):10686–93]