bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from MicroRNA-34b and MicroRNA-34c Are Targets of p53 and Cooperate in Control of Cell Proliferation and Adhesion-Independent Growth
Authors: Corney David C. , Flesken-Nikitin Andrea , Godwin Andrew K. , Wang Wei , Nikitin Alexander Yu.
Published: March 2023

Abstract
MicroRNAs (miRNA) are a recently discovered class of noncoding RNAs that negatively regulate gene expression. Recent evidence indicates that miRNAs may play an important role in cancer. However, the mechanism of their deregulation in neoplastic transformation has only begun to be understood. To elucidate the role of tumor suppressor p53 in regulation of miRNAs, we have analyzed changes in miRNA microarray expression profile immediately after conditional inactivation of p53 in primary mouse ovarian surface epithelium cells. Among the most significantly affected miRNAs were miR-34b and miR-34c, which were down-regulated 12-fold according to quantitative reverse transcription–PCR analysis. Computational promoter analysis of the mir-34b/mir-34c locus identified the presence of evolutionarily conserved p53 binding sites ∼3 kb upstream of the miRNA coding sequence. Consistent with evolutionary conservation, mir-34b/mir-34c were also down-regulated in p53-null human ovarian carcinoma cells. Furthermore, as expected from p53 binding to the mir-34b/c promoter, doxorubicin treatment of wild-type, but not p53-deficient, cells resulted in an increase of mir-34b/mir-34c expression. Importantly, miR-34b and miR-34c cooperate in suppressing proliferation and soft-agar colony formation of neoplastic epithelial ovarian cells, in agreement with the partially overlapping spectrum of their predicted targets. Taken together, these results show the existence of a novel mechanism by which p53 suppresses such critical components of neoplastic growth as cell proliferation and adhesion-independent colony formation. [Cancer Res 2007;67(18):8433–8]
Data from ELMO1 and Dock180, a Bipartite Rac1 Guanine Nucleotide Exchange Factor, Promote Human Glioma Cell Invasion
Authors: Jarzynka Michael J. , Hu Bo , Hui Kwok-Min , Bar-Joseph Ifat , Gu Weisong , Hirose Takanori , Haney Lisa B. , Ravichandran Kodi S. , Nishikawa Ryo , Cheng Shi-Yuan
Published: March 2023

Abstract
A distinct feature of malignant gliomas is the intrinsic ability of single tumor cells to disperse throughout the brain, contributing to the failure of existing therapies to alter the progression and recurrence of these deadly brain tumors. Regrettably, the mechanisms underlying the inherent invasiveness of glioma cells are poorly understood. Here, we report for the first time that engulfment and cell motility 1 (ELMO1) and dedicator of cytokinesis 1 (Dock180), a bipartite Rac1 guanine nucleotide exchange factor (GEF), are evidently linked to the invasive phenotype of glioma cells. Immunohistochemical analysis of primary human glioma specimens showed high expression levels of ELMO1 and Dock180 in actively invading tumor cells in the invasive areas, but not in the central regions of these tumors. Elevated expression of ELMO1 and Dock180 was also found in various human glioma cell lines compared with normal human astrocytes. Inhibition of endogenous ELMO1 and Dock180 expression significantly impeded glioma cell invasion in vitro and in brain tissue slices with a concomitant reduction in Rac1 activation. Conversely, exogenous expression of ELMO1 and Dock180 in glioma cells with low level endogenous expression increased their migratory and invasive capacity in vitro and in brain tissue. These data suggest that the bipartite GEF, ELMO1 and Dock180, play an important role in promoting cancer cell invasion and could be potential therapeutic targets for the treatment of diffuse malignant gliomas. [Cancer Res 2007;67(15):7203–11]
Data from The Ubiquitin-Interacting Motif–Containing Protein RAP80 Interacts with BRCA1 and Functions in DNA Damage Repair Response
Authors: Yan Jun , Kim Yong-Sik , Yang Xiao-Ping , Li Li-Ping , Liao Grace , Xia Fen , Jetten Anton M.
Published: March 2023

Abstract
In this study, we examine the potential role of receptor-associated protein 80 (RAP80), a nuclear protein containing two ubiquitin-interacting motifs (UIM), in DNA damage response and double-strand break (DSB) repair. We show that following ionizing radiation and treatment with DNA-damaging agents, RAP80 translocates to discrete nuclear foci that colocalize with those of γ-H2AX. The UIMs and the region of amino acids 204 to 304 are critical for the relocalization of RAP80 to ionizing radiation–induced foci (IRIF). These observations suggest that RAP80 becomes part of a DNA repair complex at the sites of IRIF. We also show that RAP80 forms a complex with the tumor repressor BRCA1 and that this interaction is mediated through the BRCA1 COOH-terminal repeats of BRCA1. The UIMs are not required for the interaction of RAP80 with BRCA1. Knockdown of RAP80 in HEK293 cells significantly reduced DSB-induced homology-directed recombination (HDR). Moreover, inhibition of RAP80 expression by small interfering RNA increased radiosensitivity, whereas increased radioresistance was observed in human breast cancer MCF-7 cells with overexpression of RAP80. Taken together, our data suggest that RAP80 plays an important role in DNA damage response signaling and HDR-mediated DSB repair. We further show that RAP80 can function as a substrate of the ataxia-telangiectasia mutated protein kinase in vitro, which phosphorylates RAP80 at Ser205 and Ser402. We show that this phosphorylation is not required for the migration of RAP80 to IRIF. [Cancer Res 2007;67(14):6647–56]
Data from A Comparison of DNA Copy Number Profiling Platforms
Authors: Greshock Joel , Feng Bin , Nogueira Cristina , Ivanova Elena , Perna Ilana , Nathanson Katherine , Protopopov Alexei , Weber Barbara L. , Chin Lynda
Published: March 2023

Abstract
The accurate mapping of recurring DNA copy number aberrations (CNAs), a hallmark feature of the cancer genome, has facilitated the discovery of tumor suppressor genes and oncogenes. Microarray-based assays designed to detect these chromosomal copy number alterations on a genome-wide and high-resolution scale have emerged as a cornerstone technology in the genomic era. The diversity of commercially available platforms prompted a systematic comparison of five copy number profiling assays for their ability to detect 2-fold copy number gain and loss (4n or 1n, respectively) as well as focal high-amplitude CNAs. Here, using a collection of established human melanoma cell lines, we defined the reproducibility, absolute signals, signal to noise, and false-positive and false-negative rates for each of the five assays against ground truth defined by spectral karyotyping, in addition to comparing the concordance of CNA detection by two high-resolution Agilent and Affymetrix microarray platforms. Our analyses concluded that the Agilent's 60-mer oligonucleotide microarray with probe design optimized for genomic hybridization offers the highest sensitivity and specificity (area under receiver operator characteristic curve >0.99), whereas Affymetrix's single nucleotide polymorphism microarray seems to offer better detection of CNAs in gene-poor regions. Availability of these comparison results should guide study design decisions and facilitate further computational development. [Cancer Res 2007;67(21):10173–80]
Data from Activation of the Signal Transducers and Activators of the Transcription 3 Pathway in Alveolar Epithelial Cells Induces Inflammation and Adenocarcinomas in Mouse Lung
Authors: Li Yuan , Du Hong , Qin Yulin , Roberts Jennifer , Cummings Oscar W. , Yan Cong
Published: March 2023

Abstract
The lung is an organ for host defense to clear up pathogens through innate and adaptive immunity. This process involves up-regulation of proinflammatory cytokines and chemokines that lead to activation of the signal transducers and activators of the transcription 3 (Stat3) signaling pathway. Overexpression of Stat3C in alveolar type II epithelial cells of CCSP-rtTA/(tetO)7-Stat3C bitransgenic mice leads to severe pulmonary inflammation, including immune cell infiltration and up-regulation of proinflammatory cytokines and chemokines in the lung. As a consequence, spontaneous lung bronchoalveolar adenocarcinoma was observed in bitransgenic mice. Aberrantly expressed genes in the bitransgenic model were identified and served as biomarkers for human bronchoalveolar adenocarcinoma. During tumorigenesis, genes that are critical to epithelial cell proliferation in lung development were reactivated. Therefore, Stat3 is a potent proinflammatory molecule that directly causes spontaneous lung cancer in vivo. [Cancer Res 2007;67(18):8494–503]
Data from Lupeol Suppresses Cisplatin-Induced Nuclear Factor-κB Activation in Head and Neck Squamous Cell Carcinoma and Inhibits Local Invasion and Nodal Metastasis in an Orthotopic Nude Mouse Model
Authors: Lee Terence K. , Poon Ronnie T.P. , Wo Jana Y. , Ma Stephanie , Guan Xin-Yuan , Myers Jeffrey N. , Altevogt Peter , Yuen Anthony P.W.
Published: March 2023

Abstract
A poor prognosis in head and neck squamous cell carcinoma (HNSCC) patients is commonly associated with the presence of regional metastasis. Cisplatin-based chemotherapy concurrent with radiation therapy is commonly used in the treatment of locally advanced HNSCC. However, the result is dismal due to common acquisition of chemoresistance and radioresistance. Epidemiologic studies have shown the importance of dietary substances in the prevention of HNSCC. Here, we found that lupeol, a triterpene found in fruits and vegetables, selectively induced substantial HNSCC cell death but exhibited only a minimal effect on a normal tongue fibroblast cell line in vitro. Down-regulation of NF-κB was identified as the major mechanism of the anticancer properties of lupeol against HNSCC. Lupeol alone was not only found to suppress tumor growth but also to impair HNSCC cell invasion by reversal of the NF-κB–dependent epithelial-to-mesenchymal transition. Lupeol exerted a synergistic effect with cisplatin, resulting in chemosensitization of HNSCC cell lines with high NF-κB activity in vitro. In in vivo studies, using an orthotopic metastatic nude mouse model of oral tongue squamous cell carcinoma, lupeol at a dose of 2 mg/animal dramatically decreased tumor volume and suppressed local metastasis, which was more effective than cisplatin alone. Lupeol exerted a significant synergistic cytotoxic effect when combined with low-dose cisplatin without side effects. Our results suggest that lupeol may be an effective agent either alone or in combination for treatment of advanced tumors. [Cancer Res 2007;67(18):8800–9]
Data from Cytochrome P450 Epoxygenase Promotes Human Cancer Metastasis
Authors: Jiang Jian-Gang , Ning Yao-Gui , Chen Chen , Ma Ding , Liu Zhen-Jun , Yang Shilin , Zhou Jianfeng , Xiao Xiao , Zhang Xin A. , Edin Matthew L. , Card Jeffrey W. , Wang Jianing , Zeldin Darryl C. , Wang Dao Wen
Published: March 2023

Abstract
Cytochrome P450 (CYP) epoxygenases convert arachidonic acid to four regioisomeric epoxyeicosatrienoic acids (EET), which exert diverse biological activities in a variety of systems. We previously reported that the CYP2J2 epoxygenase is overexpressed in human cancer tissues and cancer cell lines and that EETs enhance tumor growth, increase carcinoma cell proliferation, and prevent apoptosis of cancer cells. Herein, we report that CYP epoxygenase overexpression or EET treatment promotes tumor metastasis independent of effects on tumor growth. In four different human cancer cell lines in vitro, overexpression of CYP2J2 or CYP102 F87V with an associated increase in EET production or addition of synthetic EETs significantly induced Transwell migration (4.5- to 5.5-fold), invasion of cells (3- to 3.5-fold), cell adhesion to fibronectin, and colony formation in soft agar. In contrast, the epoxygenase inhibitor 17-ODYA or infection with the antisense recombinant adeno-associated viral vector (rAAV)-CYP2J2 vector inhibited cell migration, invasion, and adhesion with an associated reduction in EET production. CYP overexpression also enhanced metastatic potential in vivo in that rAAV-CYP2J2–infected MDA-MB-231 human breast carcinoma cells showed 60% more lung metastases in athymic BALB/c mice and enhanced angiogenesis in and around primary tumors compared with control cells. Lung metastasis was abolished by infection with the antisense rAAV-CYP2J2 vector. CYP epoxygenase overexpression or EET treatment up-regulated the prometastatic matrix metalloproteinases and CD44 and down-regulated the antimetastatic genes CD82 and nm-23. Together, these data suggest that CYP epoxygenase inhibition may represent a novel approach to prevent metastasis of human cancers. [Cancer Res 2007;67(14):6665–74]
Data from Elevated Interleukin-6 and G-CSF in Human Pancreatic Cancer Cell Conditioned Medium Suppress Dendritic Cell Differentiation and Activation
Authors: Bharadwaj Uddalak , Li Min , Zhang Rongxin , Chen Changyi , Yao Qizhi
Published: March 2023

Abstract
Although dendritic cell (DC) function is impaired in pancreatic cancer patients, the underlying mechanisms are unknown. This study analyzed the soluble factors released by pancreatic cancer cells responsible for inhibiting DC differentiation and activation. Medium conditioned by a highly metastatic human pancreatic cancer cell line BxPC-3 [BxPC-3 conditioned medium (BxCM)] was mainly used for the study. Both CD34+ hematopoietic progenitor cell–derived and CD14+ monocyte-derived immature DCs and mature DCs (mDCs) were inhibited by BxCM. Allostimulation of CD4+ and CD8+ T cells by BxCM-treated mDCs was inefficient and resulted in production of lower levels of Th1 and Th2 cytokines. Antigen-specific T-cell activation capability was also reduced in BxCM-treated mDCs. Addition of exogenous interleukin-6 (IL-6) and granulocyte colony-stimulating factor (G-CSF), which were present in high amounts in BxCM, mimicked the inhibitory effect of BxCM on DC differentiation and maturation. IL-6 was able to suppress DC differentiation and G-CSF mainly acted on the suppressing allostimulatory capacity of DCs. In addition, pancreatic cancer patient sera were able to inhibit DC differentiation of CD14+ monocytes obtained from healthy donors. Depleting IL-6 or G-CSF from BxCM could reverse the DC-inhibitory properties of BxCM. Furthermore, BxCM, IL-6, or G-CSF led to the activation of signal transducer and activator of transcription 3 (STAT3) in CD14+ monocytes to different degrees. Blocking BxCM-induced STAT3 activation also reversed the inhibitory effect of BxCM on DC differentiation. Therefore, IL-6 and G-CSF in BxCM represent two main factors responsible for suppression of DC differentiation, maturation, and antigen presentation, and this suppression of DC functions may be due to the aberrant activation of STAT3 by BxCM. [Cancer Res 2007;67(11):5479–88]
Data from Intratumoral Delivery and Suppression of Prostate Tumor Growth by Attenuated Salmonella enterica serovar typhimurium Carrying Plasmid-Based Small Interfering RNAs
Authors: Zhang Ling , Gao Lifang , Zhao Lijuan , Guo Baofeng , Ji Kun , Tian Yong , Wang Jinguo , Yu Hao , Hu Jiadi , Kalvakolanu Dhananjaya V. , Kopecko Dennis J. , Zhao Xuejian , Xu De-Qi
Published: March 2023

Abstract
The facultative anaerobic, invasive Salmonella enterica serovar typhimurium (S. typhimurium) has been shown to retard the growth of established tumors. We wondered if a more effective antitumor response could be achieved in vivo if these bacteria were used as tools for delivering specific molecular antitumor therapeutics. Constitutively activated transcription factor signal transducer and activator of transcription 3 (STAT3) promotes the survival of a number of human tumors. In this study, we investigated the relative efficacies of attenuated S. typhimurium alone or combined with Stat3-specific small interfering RNA (siRNA) in terms of tumor growth and metastasis. The bacteria preferentially homed into tumors over normal liver and spleen tissues in vivo. S. typhimurium expressing plasmid-based Stat3-specific siRNAs significantly inhibited tumor growth, reduced the number of metastastic organs, and extended the life time for C57BL6 mice bearing an implanted prostate tumor, versus bacterial treatment alone. These results suggest that attenuated S. typhimurium combined with an RNA interference approach might be more effective for the treatment of primary as well as metastatic cancer. [Cancer Res 2007;67(12):5859–64]
Data from Twist Transcriptionally Up-regulates AKT2 in Breast Cancer Cells Leading to Increased Migration, Invasion, and Resistance to Paclitaxel
Authors: Cheng George Z. , Chan Joseph , Wang Qi , Zhang Weizhou , Sun Calvin D. , Wang Lu-Hai
Published: March 2023

Abstract
Metastasis, the cardinal feature of malignant tumors, is an important clinical variable in patient prognosis. To understand the basis for metastasis, we systematically selected for highly invasive cells from breast cancer cell lines, MCF7 and MDA-MB-453, with moderate to low invasive ability using Boyden chamber invasion assay. The four-cycle selected invasive lines, named MCF7-I4 and MDA-MB-453-I4, respectively, displayed epithelial-mesenchymal transition (EMT) and dramatically enhanced invasive ability. EMT changes were corroborated with decreased level of E-cadherin and increased vimentin, fibronectin, and β1 integrin. Twist, a basic helix-loop-helix transcription factor, and AKT2, a known proto-oncogene, were found to be elevated in the invasive cells compared with the parental. Ectopic expression and knockdown of Twist by short interference RNA resulted in significant increase and reduction, respectively, of AKT2 protein and mRNA expression. Twist bound to E-box elements on AKT2 promoter and enhanced its transcriptional activity. Moreover, silencing AKT2 decreased Twist-promoted migration, invasion, and paclitaxel resistance. Reintroducing AKT2 largely rescued the phenotype resulted from knockdown of Twist in I4 cells, suggesting that AKT2 is a downstream target and functional mediator of Twist. Finally, we observed a 68.8% correlation of elevated Twist and AKT2 expression in late-stage breast cancers as oppose to 13% in early-stage breast cancers. Our study identifies Twist as a positive transcriptional regulator of AKT2 expression, and Twist-AKT2 signaling is involved in promoting invasive ability and survival of breast cancer cells. [Cancer Res 2007;67(5):1979–87]
Data from Haplotype Analysis of CYP11A1 Identifies Promoter Variants Associated with Breast Cancer Risk
Authors: Yaspan Brian L. , Breyer Joan P. , Cai Qiuyin , Dai Qi , Elmore J. Bradford , Amundson Isaac , Bradley Kevin M. , Shu Xiao-Ou , Gao Yu-Tang , Dupont William D. , Zheng Wei , Smith Jeffrey R.
Published: March 2023

Abstract
The CYP11A1 gene encodes the cholesterol side chain cleavage enzyme that catalyzes the initial and rate-limiting step of steroidogenesis. A large number of epidemiologic studies have implicated the duration and degree of endogenous estrogen exposure in the development of breast cancer in women. Here, we conduct a systematic investigation of the role of genetic variation of the CYP11A1 gene in breast cancer risk in a study of 1193 breast cancer cases and 1310 matched controls from the Shanghai Breast Cancer Study. We characterize the genetic architecture of the CYP11A1 gene in a Chinese study population. We then genotype tagging polymorphisms to capture common variation at the locus for tests of association. Variants designating a haplotype encompassing the gene promoter are significantly associated with both increased expression (P = 1.6e−6) and increased breast cancer risk: heterozygote age-adjusted odds ratio (OR), 1.51 [95% confidence interval (95% CI), 1.19–1.91]; homozygote age-adjusted OR, 2.94 (95% CI, 1.22–7.12), test for trend, P = 5.0e−5. Among genes controlling endogenous estrogen metabolism, CYP11A1 harbors common variants that may influence expression to significantly modify risk of breast cancer. [Cancer Res 2007;67(12):5673–82]
Data from Evidence that in Xeroderma Pigmentosum Variant Cells, which Lack DNA Polymerase η, DNA Polymerase ι Causes the Very High Frequency and Unique Spectrum of UV-Induced Mutations
Authors: Wang Yun , Woodgate Roger , McManus Terrence P. , Mead Samantha , McCormick J. Justin , Maher Veronica M.
Published: March 2023

Abstract
Xeroderma pigmentosum variant (XPV) patients have normal DNA excision repair, yet are predisposed to develop sunlight-induced cancer. They exhibit a 25-fold higher than normal frequency of UV-induced mutations and very unusual kinds (spectrum), mainly transversions. The primary defect in XPV cells is the lack of functional DNA polymerase (Pol) η, the translesion synthesis DNA polymerase that readily inserts adenine nucleotides opposite photoproducts involving thymine. The high frequency and striking difference in kinds of UV-induced mutations in XPV cells strongly suggest that, in the absence of Pol η, an abnormally error-prone polymerase substitutes. In vitro replication studies of Pol ι show that it replicates past 5′T-T3′ and 5′T-U3′ cyclobutane pyrimidine dimers, incorporating G or T nucleotides opposite the 3′ nucleotide. To test the hypothesis that Pol ι causes the high frequency and abnormal spectrum of UV-induced mutations in XPV cells, we identified an unlimited lifespan XPV cell line expressing two forms of Pol ι, whose frequency of UV-induced mutations is twice that of XPV cells expressing one form. We eliminated expression of one form and compared the parental cells and derivatives for the frequency and kinds of UV-induced mutations. All exhibited similar sensitivity to the cytotoxicity of UV(254 nm), and the kinds of mutations induced were identical, but the frequency of mutations induced in the derivatives was reduced to ≤50% that of the parent. These data strongly support the hypothesis that in cells lacking Pol η, Pol ι is responsible for the high frequency and abnormal spectrum of UV-induced mutations, and ultimately their malignant transformation. [Cancer Res 2007;67(7):3018–26]
Data from Initial Analyses of Colon Cancer–Specific Antigen (CCSA)-3 and CCSA-4 as Colorectal Cancer–Associated Serum Markers
Authors: Leman Eddy S. , Schoen Robert E. , Weissfeld Joel L. , Cannon Grant W. , Sokoll Lori J. , Chan Daniel W. , Getzenberg Robert H.
Published: March 2023

Abstract
Colon cancer–specific antigen (CCSA)-3 and CCSA-4 are novel colon cancer markers identified by focused proteomic analysis of nuclear structural proteins. The goal of these studies was to evaluate serum-based CCSA-3 and CCSA-4 in the detection of individuals with preneoplastic and neoplastic lesions using ELISAs. Serum samples from 107 subjects undergoing colonoscopy, 28 subjects with colorectal cancer, and 125 subjects with benign disease or other types of cancer were evaluated. Individuals who underwent colonoscopy were classified into mutually exclusive categories, including normal colon, hyperplastic polyp, nonadvanced adenoma, and advanced adenoma. Sensitivity and specificity for both CCSA-3 and CCSA-4 were evaluated using receiver operating characteristic (ROC) curves. At a cutoff of 2 μg/mL for CCSA-3 and 0.3 μg/mL for CCSA-4, each marker detected all 28 colorectal cancers, for a sensitivity of 100% (lower 95% confidence bound, 89.8%). The sensitivity for detection of the combined end point of colorectal cancer and advanced adenoma for CCSA-3 was 89.1% [95% confidence interval (95% CI), 76.4–96.4%] and for CCSA-4 was 84.8% (95% CI, 71.1–93.7%) and 91.3% (95% CI, 79.2–97.6%) for either marker positive. The specificity in individuals with normal, hyperplastic polyps, or nonadvanced adenomas was 82.0% (95% CI, 72.4–89.4%) and 91.0% (95% CI, 83.0–96.0%) for CCSA-3 and CCSA-4, respectively. ROC curves for CCSA-3 and CCSA-4 reveal an area under the curve of 0.94 (95% CI, 0.90–0.98%). In these initial analyses, CCSA-3 and CCSA-4 show promise as potential serum markers for detection of colorectal cancer and advanced adenomas. [Cancer Res 2007;67(12):5600–5]
Data from Identification of Epigenetically Silenced Genes in Tumor Endothelial Cells
Authors: Hellebrekers Debby M.E.I. , Melotte Veerle , Viré Emmanuelle , Langenkamp Elise , Molema Grietje , Fuks François , Herman James G. , Van Criekinge Wim , Griffioen Arjan W. , van Engeland Manon
Published: March 2023

Abstract
Tumor angiogenesis requires intricate regulation of gene expression in endothelial cells. We recently showed that DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors directly repress endothelial cell growth and tumor angiogenesis, suggesting that epigenetic modifications mediated by DNMTs and HDAC are involved in regulation of endothelial cell gene expression during tumor angiogenesis. To understand the mechanisms behind the epigenetic regulation of tumor angiogenesis, we used microarray analysis to perform a comprehensive screen to identify genes down-regulated in tumor-conditioned versus quiescent endothelial cells, and reexpressed by 5-aza-2′-deoxycytidine (DAC) and trichostatin A (TSA). Among the 81 genes identified, 77% harbored a promoter CpG island. Validation of mRNA levels of a subset of genes confirmed significant down-regulation in tumor-conditioned endothelial cells and reactivation by treatment with a combination of DAC and TSA, as well as by both compounds separately. Silencing of these genes in tumor-conditioned endothelial cells correlated with promoter histone H3 deacetylation and loss of H3 lysine 4 methylation, but did not involve DNA methylation of promoter CpG islands. For six genes, down-regulation in microdissected human tumor endothelium was confirmed. Functional validation by RNA interference revealed that clusterin, fibrillin 1, and quiescin Q6 are negative regulators of endothelial cell growth and angiogenesis. In summary, our data identify novel angiogenesis-suppressing genes that become silenced in tumor-conditioned endothelial cells in association with promoter histone modifications and reactivated by DNMT and HDAC inhibitors through reversal of these epigenetic modifications, providing a mechanism for epigenetic regulation of tumor angiogenesis. [Cancer Res 2007;67(9):4138–48]
Data from Molecular Features of Hormone-Refractory Prostate Cancer Cells by Genome-Wide Gene Expression Profiles
Authors: Tamura Kenji , Furihata Mutsuo , Tsunoda Tatsuhiko , Ashida Shingo , Takata Ryo , Obara Wataru , Yoshioka Hiroki , Daigo Yataro , Nasu Yasutomo , Kumon Hiromi , Konaka Hiroyuki , Namiki Mikio , Tozawa Keiichi , Kohri Kenjiro , Tanji Nozomu , Yokoyama Masayoshi , Shimazui Toru , Akaza Hideyuki , Mizutani Yoichi , Miki Tsuneharu , Fujioka Tomoaki , Shuin Taro , Nakamura Yusuke , Nakagawa Hidewaki
Published: March 2023

Abstract
One of the most critical issues in prostate cancer clinic is emerging hormone-refractory prostate cancers (HRPCs) and their management. Prostate cancer is usually androgen dependent and responds well to androgen ablation therapy. However, at a certain stage, they eventually acquire androgen-independent and more aggressive phenotype and show poor response to any anticancer therapies. To characterize the molecular features of clinical HRPCs, we analyzed gene expression profiles of 25 clinical HRPCs and 10 hormone-sensitive prostate cancers (HSPCs) by genome-wide cDNA microarrays combining with laser microbeam microdissection. An unsupervised hierarchical clustering analysis clearly distinguished expression patterns of HRPC cells from those of HSPC cells. In addition, primary and metastatic HRPCs from three patients were closely clustered regardless of metastatic organs. A supervised analysis and permutation test identified 36 up-regulated genes and 70 down-regulated genes in HRPCs compared with HSPCs (average fold difference > 1.5; P < 0.0001). We observed overexpression of AR, ANLN, and SNRPE and down-regulation of NR4A1, CYP27A1, and HLA-A antigen in HRPC progression. AR overexpression is likely to play a central role of hormone-refractory phenotype, and other genes we identified were considered to be related to more aggressive phenotype of clinical HRPCs, and in fact, knockdown of these overexpressing genes by small interfering RNA resulted in drastic attenuation of prostate cancer cell viability. Our microarray analysis of HRPC cells should provide useful information to understand the molecular mechanism of HRPC progression and to identify molecular targets for development of HRPC treatment. [Cancer Res 2007;67(11):5117–25]
Data from Increased Expression of the E3 Ubiquitin Ligase RNF5 Is Associated with Decreased Survival in Breast Cancer
Authors: Bromberg Kenneth D. , Kluger Harriet M. , Delaunay Agnes , Abbas Sabiha , DiVito Kyle A. , Krajewski Stan , Ronai Ze'ev
Published: March 2023

Abstract
The selective ubiquitination of proteins by ubiquitin E3 ligases plays an important regulatory role in control of cell differentiation, growth, and transformation and their dysregulation is often associated with pathologic outcomes, including tumorigenesis. RNF5 is an E3 ubiquitin ligase that has been implicated in motility and endoplasmic reticulum stress response. Here, we show that RNF5 expression is up-regulated in breast cancer tumors and related cell lines. Elevated expression of RNF5 was seen in breast cancer cell lines that became more sensitive to cytochalasin D– and paclitaxel-induced apoptosis following its knockdown with specific short interfering RNA. Inhibition of RNF5 expression markedly decreased cell proliferation and caused a reorganization of the actin cytoskeleton in response to stress in MCF-7 but not in p53 mutant breast cancer cells, suggesting a p53-dependent function. Significantly, high levels of RNF5 were associated with decreased survival in human breast cancer specimens. Similarly, RNF5 levels were higher in metastatic melanoma specimens and in melanoma, leukemia, ovarian, and renal tumor-derived cell lines, suggesting that increased RNF5 expression may be a common event during tumor progression. These results indicate that RNF5 is a novel regulator of breast cancer progression through its effect on actin cytoskeletal alterations, which also affect sensitivity of breast cancer cells to cytoskeletal targeting antineoplastic agents. [Cancer Res 2007;67(17):8172–9]
Data from The let-7 MicroRNA Represses Cell Proliferation Pathways in Human Cells
Authors: Johnson Charles D. , Esquela-Kerscher Aurora , Stefani Giovanni , Byrom Mike , Kelnar Kevin , Ovcharenko Dmitriy , Wilson Mike , Wang Xiaowei , Shelton Jeffrey , Shingara Jaclyn , Chin Lena , Brown David , Slack Frank J.
Published: March 2023

Abstract
MicroRNAs play important roles in animal development, cell differentiation, and metabolism and have been implicated in human cancer. The let-7 microRNA controls the timing of cell cycle exit and terminal differentiation in Caenorhabditis elegans and is poorly expressed or deleted in human lung tumors. Here, we show that let-7 is highly expressed in normal lung tissue, and that inhibiting let-7 function leads to increased cell division in A549 lung cancer cells. Overexpression of let-7 in cancer cell lines alters cell cycle progression and reduces cell division, providing evidence that let-7 functions as a tumor suppressor in lung cells. let-7 was previously shown to regulate the expression of the RAS lung cancer oncogenes, and our work now shows that multiple genes involved in cell cycle and cell division functions are also directly or indirectly repressed by let-7. This work reveals the let-7 microRNA to be a master regulator of cell proliferation pathways. [Cancer Res 2007;67(16):7713–22]
Data from Fundamental Differences in Cell Cycle Deregulation in Human Papillomavirus–Positive and Human Papillomavirus–Negative Head/Neck and Cervical Cancers
Authors: Pyeon Dohun , Newton Michael A. , Lambert Paul F. , den Boon Johan A. , Sengupta Srikumar , Marsit Carmen J. , Woodworth Craig D. , Connor Joseph P. , Haugen Thomas H. , Smith Elaine M. , Kelsey Karl T. , Turek Lubomir P. , Ahlquist Paul
Published: March 2023

Abstract
Human papillomaviruses (HPV) are associated with nearly all cervical cancers, 20% to 30% of head and neck cancers (HNC), and other cancers. Because HNCs also arise in HPV-negative patients, this type of cancer provides unique opportunities to define similarities and differences of HPV-positive versus HPV-negative cancers arising in the same tissue. Here, we describe genome-wide expression profiling of 84 HNCs, cervical cancers, and site-matched normal epithelial samples in which we used laser capture microdissection to enrich samples for tumor-derived versus normal epithelial cells. This analysis revealed that HPV+ HNCs and cervical cancers differed in their patterns of gene expression yet shared many changes compared with HPV− HNCs. Some of these shared changes were predicted, but many others were not. Notably, HPV+ HNCs and cervical cancers were found to be up-regulated in their expression of a distinct and larger subset of cell cycle genes than that observed in HPV− HNC. Moreover, HPV+ cancers overexpressed testis-specific genes that are normally expressed only in meiotic cells. Many, although not all, of the hallmark differences between HPV+ HNC and HPV− HNC were a direct consequence of HPV and in particular the viral E6 and E7 oncogenes. This included a novel association of HPV oncogenes with testis-specific gene expression. These findings in primary human tumors provide novel biomarkers for early detection of HPV+ and HPV− cancers, and emphasize the potential value of targeting E6 and E7 function, alone or combined with radiation and/or traditional chemotherapy, in the treatment of HPV+ cancers. [Cancer Res 2007;67(10):4605–19]
Data from Cancer Resistance in Transgenic Mice Expressing the SAC Module of Par-4
Authors: Zhao Yanming , Burikhanov Ravshan , Qiu Shirley , Lele Subodh M. , Jennings C. Darrell , Bondada Subbarao , Spear Brett , Rangnekar Vivek M.
Published: March 2023

Abstract
Prostate apoptosis response-4 (Par-4) is a tumor-suppressor protein that induces apoptosis in cancer cells, but not in normal/immortalized cells. The cancer-specific proapoptotic action of Par-4 is encoded in its centrally located SAC domain. We report here the characterization of a novel mouse model with ubiquitous expression of the SAC domain. Although SAC transgenic mice displayed normal development and life span, they were resistant to the growth of spontaneous, as well as oncogene-induced, autochthonous tumors. Resistance to tumorigenesis was linked to inhibition of nuclear factor-κB activity and induction of apoptosis by the SAC domain. Collectively, our findings provide genetic evidence that the SAC domain of Par-4 confers cancer resistance in transgenic mice without compromising normal viability or aging, and may have therapeutic significance. [Cancer Res 2007;67(19):9276–85]
Data from Extralymphatic Tumors Prepare Draining Lymph Nodes to Invasion via a T-Cell Cross-Tolerance Process
Authors: Preynat-Seauve Olivier , Contassot Emmanuel , Schuler Prisca , Piguet Vincent , French Lars E. , Huard Bertrand
Published: March 2023

Abstract
Metastases often develop in lymphoid organs. However, the immunologic mechanism allowing such invasion is not known because these organs are considered to be hostile to tumor cells. Here, we analyzed the interactions between tumor cells and CD8+ T cells in such lymphoid organs. Tumor cells implanted into lymph nodes were able to induce tumor-specific cytotoxic CD8+ T-cell responses, conducting to tumor rejection, in contrast to primary extralymphatic tumors rapidly anergizing T cells in draining lymph nodes (DLN) via a cross-presentation process. This abortive CD8+ T-cell response to extralymphatic tumor is independent of the subcellular localization of antigen in tumor cells and is consistent with a lack of CD4+ T-cell help. Notably, this anergy was potent enough to allow successful DLN implantation of tumor cells. Such distant cross-tolerization of tumor-specific CD8+ T cells may be a determinant permissive event leading to invasion of DLN. In this situation, metastatic tumor cells do not need to down-regulate their immunogenicity to spread. [Cancer Res 2007;67(10):5009–16]
Data from Genetic Screening Reveals an Essential Role of p27kip1 in Restriction of Breast Cancer Progression
Authors: Yuan Yuhui , Qin Li , Liu Dan , Wu Ray-Chang , Mussi Paola , Zhou Suoling , Songyang Zhou , Xu Jianming
Published: March 2023

Abstract
The genetic changes and mechanisms underlying the progression of estrogen-dependent breast cancers to estrogen-independent, antiestrogen-resistant, and metastatic breast cancers are unclear despite being a major problem in endocrine therapy. To identify genes responsible for this progression, we carried out a genetic screening by an enhanced retroviral mutagen (ERM)–mediated random mutagenesis in the estrogen-dependent T47D breast cancer cells. We found that T47D cells contain only one p27kip1 (p27) allele coding for the p27 cyclin-dependent kinase (CDK) inhibitor. An ERM insertion into the p27 locus of T47D cells disrupted the p27 gene and created estrogen-independent and antiestrogen-resistant breast cancer cells that still maintained functional estrogen receptors. Disruption of p27 in T47D cells resulted in several changes, and most of these changes could be rescued by p27 restoration. First, CDK2 activity was increased in the absence of estrogen or in the presence of estrogen antagonists tamoxifen or ICI 182780; second, amplified in breast cancer 1 (AIB1), a cancer overexpressed transcriptional coactivator, was hyperphosphorylated, which made AIB1 a better coactivator for E2F1; and third, growth factor receptor binding protein 2–associated binder 2 (Gab2) and Akt activity were increased following E2F1 overactivation, leading to a significant enhancement of cell migration and invasion. Furthermore, the p27-deficient cells, but not T47D control cells, developed lung metastasis in an ovarian hormone–independent manner when they were i.v. injected into nude mice. In sum, loss of p27 activated AIB1, E2F1, Gab2, and Akt; increased cell migration and invasion; caused antiestrogen insensitivity; and promoted metastasis of breast cancer cells. These findings suggest that p27 plays an essential role in restriction of breast cancer progression. [Cancer Res 2007;67(17):8032–42]
Data from ABCG2/BCRP Expression Modulates d-Luciferin–Based Bioluminescence Imaging
Authors: Zhang Yimao , Bressler Joseph P. , Neal Jeff , Lal Bachchu , Bhang Hyo-Eun C. , Laterra John , Pomper Martin G.
Published: March 2023

Abstract
Bioluminescence imaging (BLI) is becoming indispensable to the study of transgene expression during development and, in many in vivo models of disease such as cancer, for high throughput drug screening in vitro. Because reaction of d-luciferin with firefly luciferase (fLuc) produces photons of sufficiently long wavelength to permit imaging in intact animals, use of this substrate and enzyme pair has become the method of choice for performing BLI in vivo. We now show that expression of the ATP-binding cassette (ABC) family transporter ABCG2/BCRP affects BLI signal output from the substrate d-luciferin. In vitro studies show that d-luciferin is a substrate for ABCG2/BCRP but not for the MDR1 P-glycoprotein (ABCB1/Pgp), multidrug resistance protein 1 (MRP1/ABCC1), or multidrug resistance protein 2 (MRP2/ABCC2). d-Luciferin uptake within cells is shown to be modulated by ABC transporter inhibitors, including the potent and selective ABCG2/BCRP inhibitor fumitremorgin C. Images of xenografts engineered to express transgenic ABCG2/BCRP, as well as xenografts derived from the human prostate cancer cell line 22Rv1 that naturally express ABCG2/BCRP, show that ABCG2/BCRP expression and function within regions of interest substantially influence d-luciferin–dependent bioluminescent output in vivo. These findings highlight the need to consider ABCG2/BCRP effects during d-luciferin–based BLI and suggest novel high throughput methods for identifying new ABCG2/BCRP inhibitors. [Cancer Res 2007;67(19):9389–97]
Data from Activation of Toll-like Receptor 4 on Tumor Cells In vitro Inhibits Subsequent Tumor Growth In vivo
Authors: Andreani Virginia , Gatti Gerardo , Simonella Lucio , Rivero Virginia , Maccioni Mariana
Published: March 2023

Abstract
Although an eruption of information on the role of Toll-like receptor 4 (TLR4), the main receptor for bacterial lipopolysaccharide, in activating macrophages and dendritic cells has emerged, very little is known about the role of TLR4 present on epithelial cells from sterile environments like tumors. The main goal of this work was to investigate the consequences of TLR4 activation present on tumor cells in two different animal models of cancer: the Dunning rat prostate cancer and the B16 murine melanoma models. We show that (a) activating TLR4 signaling in two different tumor cell lines in vitro modifies the tumor outgrowth in vivo; (b) this effect is not due to a direct consequence of TLR4 signaling on the proliferation/apoptosis balance of the tumor cells; (c) the T-cell compartment is somehow involved in the described phenomenon because the inhibitory effect observed is not seen in athymic nude mice; and (d) tumor-infiltrating lymphocytes purified from tumors induced by TLR4-activated cells show strong induction of IFNγ transcript in detriment of interleukin-10 transcript, suggesting a change in their functionality. We hypothesize that TLR4 signaling in tumor cells in vitro induces the expression of proinflammatory mediators, which could dramatically alter the maturation state of dendritic cells present at the site of inoculation, switching the type of immune response elicited against the tumor. These results open up new avenues for understanding the role of TLR4 in tumor cells and for identifying potential new therapy strategies for cancer. [Cancer Res 2007;67(21):10519–27]
Data from Large-Scale CpG Methylation Analysis Identifies Novel Candidate Genes and Reveals Methylation Hotspots in Acute Lymphoblastic Leukemia
Authors: Taylor Kristen H. , Pena-Hernandez Keila E. , Davis J. Wade , Arthur Gerald L. , Duff Deiter J. , Shi Huidong , Rahmatpanah Farah B. , Sjahputera Ozy , Caldwell Charles W.
Published: March 2023

Abstract
This study examined DNA methylation associated with acute lymphoblastic leukemia (ALL) and showed that selected molecular targets can be pharmacologically modulated to reverse gene silencing. A CpG island (CGI) microarray containing more than 3,400 unique clones that span all human chromosomes was used for large-scale discovery experiments and led to 262 unique CGI loci being statistically identified as methylated in ALL lymphoblasts. The methylation status of 10 clones encompassing 11 genes (DCC, DLC-1, DDX51, KCNK2, LRP1B, NKX6-1, NOPE, PCDHGA12, RPIB9, ABCB1, and SLC2A14) identified as differentially methylated between ALL patients and controls was independently verified. Consequently, the methylation status of DDX51 was found to differentiate patients with B- and T-ALL subtypes (P = 0.011, Fisher's exact test). Next, the relationship between methylation and expression of these genes was examined in ALL cell lines (NALM-6 and Jurkat) before and after treatments with 5-aza-2-deoxycytidine and trichostatin A. More than a 10-fold increase in mRNA expression was observed for two previously identified tumor suppressor genes (DLC-1 and DCC) and also for RPIB9 and PCDHGA12. Although the mechanisms that lead to the CGI methylation of these genes are unknown, bisulfite sequencing of the promoter of RPIB9 suggests that expression is inhibited by methylation within SP1 and AP2 transcription factor binding motifs. Finally, specific chromosomal methylation hotspots were found to be associated with ALL. This study sets the stage for acquiring a better biological understanding of ALL and for the identification of epigenetic biomarkers useful for differential diagnosis, therapeutic monitoring, and the detection of leukemic relapse. [Cancer Res 2007;67(6):2617–25]
Data from A Vascular Targeted Pan Phosphoinositide 3-Kinase Inhibitor Prodrug, SF1126, with Antitumor and Antiangiogenic Activity
Authors: Garlich Joseph R. , De Pradip , Dey Nandini , Su Jing Dong , Peng Xiaodong , Miller Antoinette , Murali Ravoori , Lu Yiling , Mills Gordon B. , Kundra Vikas , Shu H-K. , Peng Qiong , Durden Donald L.
Published: March 2023

Abstract
PTEN and the pan phosphoinositide 3-kinase (PI3K) inhibitor 2-(4-morpholinyl)-8-phenyl-4H-1benzopyran-4-one (LY294002) exert significant control over tumor-induced angiogenesis and tumor growth in vivo. The LY294002 compound is not a viable drug candidate due to poor pharmacologic variables of insolubility and short half-life. Herein, we describe the development and antitumor activity of a novel RGDS-conjugated LY294002 prodrug, termed SF1126, which is designed to exhibit increased solubility and bind to specific integrins within the tumor compartment, resulting in enhanced delivery of the active compound to the tumor vasculature and tumor. SF1126 is water soluble, has favorable pharmacokinetics, and is well tolerated in murine systems. The capacity of SF1126 to inhibit U87MG and PC3 tumor growth was enhanced by the RGDS integrin (αvβ3/α5β1) binding component, exhibiting increased activity compared with a false RADS-targeted prodrug, SF1326. Antitumor activity of SF1126 was associated with the pharmacokinetic accumulation of SF1126 in tumor tissue and the pharmacodynamic knockdown of phosphorylated AKT in vivo. Furthermore, SF1126 seems to exhibit both antitumor and antiangiogenic activity. The results support SF1126 as a viable pan PI3K inhibitor for phase I clinical trials in cancer and provide support for a new paradigm, the application of pan PI3K inhibitory prodrugs for the treatment of cancer. [Cancer Res 2008;68(1):206–15]
Data from Direct Transcriptional Activation of Promyelocytic Leukemia Protein by IFN Regulatory Factor 3 Induces the p53-Dependent Growth Inhibition of Cancer Cells
Authors: Kim Tae-Kyung , Lee Joong-Seob , Oh Se-Yeong , Jin Xun , Choi Yun-Jaie , Lee Tae-Hoon , Lee Eun ho , Choi Young-Ki , You Seungkwon , Chung Yong Gu , Lee Jang-Bo , DePinho Ronald A. , Chin Lynda , Kim Hyunggee
Published: March 2023

Abstract
IFN regulatory factor 3 (IRF3) is a transcriptional factor that plays a crucial role in activation of innate immunity and inflammation in response to viral infection, and is also involved in p53-dependent inhibition of cell growth. Although functional activation of IRF3 by viral infection is relatively well documented, the biological role and regulatory mechanism underlying cell growth inhibition by IRF3 are poorly understood. Here, we show a novel regulatory pathway connecting IRF3-promyelocytic leukemia protein (PML)-p53 in primary and cancer cell lines. Overexpression of IRF3 induces p53-dependent cell growth inhibition in cancer cell lines with normal p53 activity. In addition, doxycycline-induced expression of IRF3 in U87MG cells inhibits tumor growth in nude mice in vivo. IRF3 is found to increase expression of PML by a direct transcriptional activation as determined by PML-promoter-luciferase and chromatin immunoprecipitation assays. When PML is depleted by RNA interference–mediated knockdown, IRF3 fails to increase p53 acetylation and its transcriptional activity. Taken together, the results of the present study indicate that direct transcriptional activation of PML by IRF3 results in the p53-dependent growth inhibition of normal and cancer cells in vitro and in vivo, which is suggestive of a novel regulatory network between the innate immune response and tumor suppression. [Cancer Res 2007;67(23):11133–40]