bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from A Laminin-Collagen Complex Drives Human Epidermal Carcinogenesis through Phosphoinositol-3-Kinase Activation
Authors: Waterman Elizabeth A. , Sakai Noriyasu , Nguyen Ngon T. , Horst Basil A.J. , Veitch Dallas P. , Dey Clara N. , Ortiz-Urda Susana , Khavari Paul A. , Marinkovich M. Peter
Published: March 2024

Abstract
Laminin-332 (formerly laminin-5) and collagen VII are basement membrane proteins expressed at the invasive front of human squamous cell carcinoma (SCC) tumors. These proteins have protumorigenic properties, but whether laminin-332 and collagen VII promote SCC tumors by providing adhesion or other nonadhesive extracellular cues, or whether laminin-332 and collagen VII interact together in this process remains unknown. In this study, we examined the role of these molecules by a structural approach using an in vivo model of human SCC tumorigenesis. Here, we show that individual domains (VI and V-III) on the laminin-332 β3 chain provide distinct and highly divergent cell adhesion and tumor-promoting functions. We found that laminin β3 domain VI provided a critical role in the assembly of stable adhesion complexes, but this domain was not required in SCC tumors. Instead, we found that laminin β3 domain V-III played an essential role in SCC carcinogenesis/invasion through binding to collagen VII, which in turn, led to phosphoinositol-3-kinase activation and protection from apoptosis. Overexpression of constitutively active p110 phosphoinositol-3-kinase subunit was sufficient to restore invasion and tumorigenesis in transformed cells lacking laminin-332/collagen VII interaction in a manner independent of cellular adhesion. These studies show distinctive adhesive and signaling functions in individual domains of laminin-332, one which is required for normal epithelial adhesion and one which is required for SCC tumorigenesis. This uncoupling of stable adhesion from tumor progression in our studies suggests that laminin-332/collagen VII interaction promotes epidermal carcinogenesis through signaling rather than adhesion. [Cancer Res 2007;67(9):4264–70]
Data from Role of Tumor Necrosis Factor-α and TRAIL in High-Dose Radiation–Induced Bystander Signaling in Lung Adenocarcinoma
Authors: Shareef Mohammed M. , Cui Nuan , Burikhanov Ravshan , Gupta Seema , Satishkumar Sabapathi , Shajahan Shahin , Mohiuddin Mohammed , Rangnekar Vivek M. , Ahmed Mansoor M.
Published: March 2024

Abstract
In the present study, ionizing radiation (IR)–induced bystander effects were investigated in two lung cancer cell lines. A549 cells were found to be more resistant to radiation-conditioned medium (RCM) obtained from A549 cells when compared with the H460 exposed to RCM procured from H460 cells. Significant release of tumor necrosis factor-α (TNF-α) was observed in A549 cells after IR/RCM exposure, and the survival was reversed with neutralizing antibody against TNF-α. In H460 cells, significant release of TNF-related apoptosis-inducing ligand (TRAIL), but not TNF-α, was observed in response to IR, RCM exposure, or RCM + 2Gy, and neutralizing antibody against TRAIL diminished clonogenic inhibition. Mechanistically, TNF-α present in RCM of A549 was found to mediate nuclear factor-κB (NF-κB) translocation to nucleus, whereas the soluble TRAIL present in RCM of H460 cells mobilized the nuclear translocation of PAR-4 (a proapoptotic protein). Analysis of IR-inducible early growth response-1 (EGR-1) function showed that EGR-1 was functional in A549 cells but not in H460 cells. A significant decrease in RCM-mediated apoptosis was observed in both A549 cells stably expressing small interfering RNA EGR-1 and EGR-1−/− mouse embryonic fibroblast cells. Thus, the high-dose IR-induced bystander responses in A549 may be dependent on the EGR-1 function and its target gene TNF-α. These findings show that the reduced bystander response in A549 cells is due to activation of NF-κB signaling by TNF-α, whereas enhanced response to IR-induced bystander signaling in H460 cells was due to release of TRAIL associated with nuclear translocation of PAR-4. [Cancer Res 2007;67(24):11811–20]
Data from Association of γ-Glutamyltransferase and Risk of Cancer Incidence in Men: A Prospective Study
Authors: Strasak Alexander M. , Rapp Kilian , Brant Larry J. , Hilbe Wolfgang , Gregory Martin , Oberaigner Willi , Ruttmann Elfriede , Concin Hans , Diem Günter , Pfeiffer Karl P. , Ulmer Hanno
Published: March 2024

Abstract
Although several epidemiologic studies have shown that γ-glutamyltransferase (GGT) is independently associated with cardiovascular disease and all-cause mortality, its relationship with cancer incidence remains widely unexplored. In several experimental models, the ability of cellular GGT to modulate crucial redox-sensitive functions has been established, and it thus may play a role in tumor progression, as has been repeatedly suggested. We prospectively investigated the association between GGT and risk of overall and site-specific cancer incidence in a large population-based cohort of 79,279 healthy Austrian men with serial GGT measurements. Median follow-up was 12.5 years. Adjusted Cox proportional hazards models were calculated to evaluate GGT as an independent predictor for cancer incidence, and nonparametric regression splines were fitted to flexibly capture the dose-response relationship. Elevated GGT significantly increased overall cancer risk, showing a clear dose-response relationship (P for GGT log-unit increase < 0.0001; P for trend < 0.0001). In comparison with the reference GGT concentration (25 units/L), we found adjusted relative risks (95% confidence intervals) equalling 1.19 (1.15-1.22) for GGT concentrations of 60 units/L, 1.32 (1.28-1.36) for 100 units/L, 1.67 (1.60-1.75) for 200 units/L, and 2.30 (2.14-2.47) for 400 units/L. In cancer site-specific models, GGT was significantly associated with malignant neoplasms of digestive organs, the respiratory system/intrathoracic organs, and urinary organs (all P < 0.0001). Age of participants significantly modified the association of GGT and cancer risk (P < 0.001), revealing markedly stronger associations in participants ages ≤65 years. Our findings, for the first time, show that elevated GGT is significantly associated with increased cancer risk in men. [Cancer Res 2008;68(10):3970–7]
Data from Effect of Vascular Normalization by Antiangiogenic Therapy on Interstitial Hypertension, Peritumor Edema, and Lymphatic Metastasis: Insights from a Mathematical Model
Authors: Jain Rakesh K. , Tong Ricky T. , Munn Lance L.
Published: March 2024

Abstract
Preclinical and clinical evidence shows that antiangiogenic agents can decrease tumor vessel permeability and interstitial fluid pressure (IFP) in a process of vessel “normalization.” The resulting normalized vasculature has more efficient perfusion, but little is known about how tumor IFP and interstitial fluid velocity (IFV) are affected by changes in transport properties of the vessels and interstitium that are associated with antiangiogenic therapy. By using a mathematical model to simulate IFP and IFV profiles in tumors, we show here that antiangiogenic therapy can decrease IFP by decreasing the tumor size, vascular hydraulic permeability, and/or the surface area per unit tissue volume of tumor vessels. Within a certain window of antiangiogenic effects, interstitial convection within the tumor can increase dramatically, whereas fluid convection out of the tumor margin decreases. This would result in increased drug convection within the tumor and decreased convection of drugs, growth factors, or metastatic cancer cells from the tumor margin into the peritumor fluid or tissue. Decreased convection of growth factors, such as vascular endothelial growth factor-C (VEGF-C), would limit peritumor hyperplasia, and decreased VEGF-A would limit angiogenesis in sentinel lymph nodes. Both of these effects would reduce the probability of lymphatic metastasis. Finally, decreased fluid convection into the peritumor tissue would decrease peritumor edema associated with brain tumors and ascites accumulation in the peritoneal or pleural cavity, a major complication with a number of malignancies. [Cancer Res 2007;67(6):2729–35]
Data from Six1 Overexpression in Mammary Cells Induces Genomic Instability and Is Sufficient for Malignant Transformation
Authors: Coletta Ricardo D. , Christensen Kimberly L. , Micalizzi Douglas S. , Jedlicka Paul , Varella-Garcia Marileila , Ford Heide L.
Published: March 2024

Abstract
Homeoproteins are transcription factors that act as master regulators of development and are frequently dysregulated in cancers. During embryogenesis, the Six1 homeoprotein is essential for the expansion of precursor cell populations that give rise to muscle and kidney, among other organs. Six1 overexpression is observed in numerous cancers, resulting in increased proliferation, survival, and metastasis. Here, we investigate whether Six1 can play a causal role in mammary tumor initiation. We show that Six1 overexpression in MCF12A mammary epithelial cells promotes multiple properties associated with malignant transformation, including increased proliferation, genomic instability, and anchorage-independent growth. We further show that this transformation is dependent on up-regulation of its transcriptional target, cyclin A1, which is normally expressed in the embryonic mammary gland but dramatically reduced in the adult gland. Six1-transformed MCF12A cells are tumorigenic in nude mice, forming aggressive tumors that are locally invasive and exhibit peritumoral lymphovascular invasion. In human breast carcinomas, expression of Six1 and cyclin A1 mRNA correlate strongly with each other (P < 0.0001), and expression of Six1 and cyclin A1 each correlate with Ki67, a marker of proliferation (P < 0.0001 and P = 0.014, respectively). Together, our data indicate that Six1 overexpression is sufficient for malignant transformation of immortalized, nontumorigenic mammary epithelial cells, and suggest that the mechanism of this transformation involves inappropriate reexpression of cyclin A1 in the adult mammary gland. [Cancer Res 2008;68(7):2204–13]
Data from CDC25B Involvement in the Centrosome Duplication Cycle and in Microtubule Nucleation
Authors: Boutros Rose , Lobjois Valérie , Ducommun Bernard
Published: March 2024

Abstract
Centrosome amplification is frequently reported in human cancers, although the molecular mechanisms that are responsible for this remain unclear. There is significant evidence to support a role for cyclin-dependent kinase (CDK)–cyclin complexes in centrosome duplication. The activities of CDK-cyclin complexes are, in turn, regulated by the CDC25 family of phosphatases in a strict spatiotemporal manner, and we have recently reported that CDC25B localizes to the centrosomes from early S phase. In the present study, we have investigated the role of centrosomally localized CDC25B in centrosome duplication. We first observed that overexpression of CDC25B under an inducible promoter in S phase results in centrosome overduplication. We found that forced expression of wild-type but not phosphatase-inactive CDC25B at the centrosomes results in centrosome amplification, aberrant microtubule organization, and abnormal accumulation of γ-tubulin. In contrast, inhibition of CDC25B phosphatase activity inhibits the assembly of interphase microtubules and the centrosomal localization of γ-tubulin. We propose that CDC25B is part of the pathway that controls the localization of γ-tubulin to the centrosomes, thereby regulating centrosome duplication during S phase and the nucleation of microtubules. We speculate that abnormal expression of CDC25B in numerous human tumors might therefore have a critical role in centrosome amplification and genomic instability. [Cancer Res 2007;67(24):11557–64]
Data from Cancer-Testis Antigen Lymphocyte Antigen 6 Complex Locus K Is a Serologic Biomarker and a Therapeutic Target for Lung and Esophageal Carcinomas
Authors: Ishikawa Nobuhisa , Takano Atsushi , Yasui Wataru , Inai Kouki , Nishimura Hitoshi , Ito Hiroyuki , Miyagi Yohei , Nakayama Haruhiko , Fujita Masahiro , Hosokawa Masao , Tsuchiya Eiju , Kohno Nobuoki , Nakamura Yusuke , Daigo Yataro
Published: March 2024

Abstract
Gene expression profile analyses of non–small cell lung carcinomas (NSCLC) and esophageal squamous cell carcinomas (ESCC) revealed that lymphocyte antigen 6 complex locus K (LY6K) was specifically expressed in testis and transactivated in a majority of NSCLCs and ESCCs. Immunohistochemical staining using 406 NSCLC and 265 ESCC specimens confirmed that LY6K overexpression was associated with poor prognosis for patients with NSCLC (P = 0.0003), as well as ESCC (P = 0.0278), and multivariate analysis confirmed its independent prognostic value for NSCLC (P = 0.0035). We established an ELISA to measure serum LY6K and found that the proportion of the serum LY6K-positive cases was 38 of 112 (33.9%) NSCLC and 26 of 81 (32.1%) ESCC, whereas only 3 of 74 (4.1%) healthy volunteers were falsely diagnosed. In most cases, there was no correlation between serum LY6K and conventional tumor markers of carcinoembryonic antigen (CEA) and cytokeratin 19-fragment (CYFRA 21-1) values. A combined ELISA for both LY6K and CEA classified 64.7% of lung adenocarcinoma patients as positive, and the use of both LY6K and CYFRA 21-1 increased sensitivity in the detection of lung squamous cell carcinomas and ESCCs up to 70.4% and 52.5%, respectively, whereas the false positive rate was 6.8% to 9.5%. In addition, knocked down of LY6K expression with small interfering RNAs resulted in growth suppression of the lung and esophageal cancer cells. Our data imply that a cancer-testis antigen, LY6K, should be useful as a new type of tumor biomarker and probably as a target for the development of new molecular therapies for cancer treatment. [Cancer Res 2007;67(24):11536–46]
Data from Glutathione S-Transferase P1: Gene Sequence Variation and Functional Genomic Studies
Authors: Moyer Ann M. , Salavaggione Oreste E. , Wu Tse-Yu , Moon Irene , Eckloff Bruce W. , Hildebrandt Michelle A.T. , Schaid Daniel J. , Wieben Eric D. , Weinshilboum Richard M.
Published: March 2024

Abstract
Glutathione S-transferase P1 (GSTP1) is of importance for cancer research because of its role in detoxifying carcinogens, activating antineoplastic prodrugs, metabolizing chemotherapeutic agents, and its involvement in cell cycle and apoptosis regulation. Two common GSTP1 genetic polymorphisms have been studied extensively. However, the full range of GSTP1 genetic variation has not been systematically characterized in the absence of disease pathology. We set out to identify common GSTP1 polymorphisms in four ethnic groups, followed by functional genomic studies. All exons, splice junctions, and the 5′-flanking region of GSTP1 were resequenced using 60 DNA samples each from four ethnic groups. The 35 single-nucleotide polymorphisms (SNP) identified included six nonsynonymous SNPs and 17 previously unreported polymorphisms. GSTP1 variant allozymes were then expressed in COS-1 cells, and five displayed significantly altered levels of enzyme activity. One decreased to 22% of the wild-type (WT) activity. Four variant allozymes had Km values that differed significantly from that of the WT, and five showed altered levels of immunoreactive protein compared with WT, with a significant correlation (r = 0.79, P < 0.007) between levels of immunoreactive protein and enzyme activity in these samples. In the Mexican American population, five linked SNPs were significantly associated with GSTP1 mRNA expression, one of which was found by electrophoretic mobility shift assay to alter protein binding. These studies have identified functionally significant genetic variation, in addition to the two frequently studied GSTP1 nonsynonymous SNPs, that may influence GSTP1's contribution to carcinogen and drug metabolism, and possibly disease pathogenesis and/or drug response. [Cancer Res 2008;68(12):4791–801]
Data from Mitochondrial/Cell-Surface Protein p32/gC1qR as a Molecular Target in Tumor Cells and Tumor Stroma
Authors: Fogal Valentina , Zhang Lianglin , Krajewski Stan , Ruoslahti Erkki
Published: March 2024

Abstract
A tumor homing peptide, LyP-1, selectively binds to tumor-associated lymphatic vessels and tumor cells in certain tumors and exhibits an antitumor effect. Here, we show that the protein known as p32 or gC1q receptor is the receptor for LyP-1. Various human tumor cell lines were positive for p32 expression in culture, and the expression was increased in xenograft tumors grown from the positive cell lines. Fluorescence-activated cell sorting analyses with anti-p32 antibodies showed that p32-positive cell lines expressed p32 at the cell surface. These cells bound and internalized LyP-1 peptide in proportion to the cell-surface expression level, which correlated with malignancy rather than total p32 expression in the cells. Like the LyP-1 peptide, p32 antibodies highlighted hypoxic areas in tumors, where they bound to both tumor cells and cells that expressed macrophage/myeloid cell markers and often seemed to be incorporated into the walls of tumor lymphatics. Significant p32 expression was common in human cancers and the p32 levels were often greatly elevated compared with the corresponding normal tissue. These results establish p32, particularly its cell-surface–expressed form, as a new marker of tumor cells and tumor-associated macrophages/myeloid cells in hypoxic/metabolically deprived areas of tumors. Its unique localization in tumors and its relative tumor specificity may make p32 a useful target in tumor diagnosis and therapy. [Cancer Res 2008;68(17):7210–8]
Data from 16-kDa Prolactin Inhibits Endothelial Cell Migration by Down-Regulating the Ras-Tiam1-Rac1-Pak1 Signaling Pathway
Authors: Lee Sok-Hyong , Kunz Jeannette , Lin Sue-Hwa , Yu-Lee Li-yuan
Published: March 2024

Abstract
Angiogenesis plays a key role in promoting tumorigenesis and metastasis. The 16-kDa fragment of prolactin (16k PRL) is an NH2-terminal natural breakdown fragment of the intact 23-kDa prolactin and has been shown to have potent antiangiogenic and antitumor activities. The mechanism(s) involved in the action of 16k PRL in endothelial cells remains unclear. In this study, we showed that 16k PRL reduced rat aortic endothelial cell (RAEC) migration in a wound-healing assay and in a Matrigel tube formation assay, suggesting that 16k PRL inhibits endothelial cell migration, an important activity involved in angiogenesis and tumorigenesis. We further investigated how 16k PRL attenuates endothelial cell migration. We first showed that RAEC migration is mediated through the Rho GTPase Rac1, as Rac1 inhibition by the Rac1-specific inhibitor NSC27366 or Rac1 knockdown by small interfering RNA both blocked RAEC migration. We next showed that 16k PRL reduced the activation of Rac1 in a concentration-dependent manner. Furthermore, 16k PRL inhibition of Rac1 is mediated through the suppression of T lymphoma invasion and metastasis 1 (Tiam1) and its upstream activator Ras in a phosphoinositide-3-kinase–independent manner. 16k PRL also down-regulated the phosphorylation of the downstream effector of Rac1, p21-activating kinase 1 (Pak1), and inhibited its translocation to the leading edge of migrating cells. Thus, 16k PRL inhibits cell migration by blocking the Ras-Tiam1-Rac1-Pak1 signaling pathway in endothelial cells. [Cancer Res 2007;67(22):11045–53]
Data from Sigma-1 Receptors Bind Cholesterol and Remodel Lipid Rafts in Breast Cancer Cell Lines
Authors: Palmer Christopher P. , Mahen Robert , Schnell Eva , Djamgoz Mustafa B.A. , Aydar Ebru
Published: March 2024

Abstract
Lipid rafts are membrane platforms that spatially organize molecules for specific signaling pathways that regulate various cellular functions. Cholesterol is critical for liquid-ordered raft formation by serving as a spacer between the hydrocarbon chains of sphingolipids, and alterations in the cholesterol contents of the plasma membrane causes disruption of rafts. The role that σ receptors play in cancer is not clear, although it is frequently up-regulated in human cancer cells and tissues and σ receptors inhibit proliferation in carcinoma and melanoma cell lines, induce apoptosis in colon and mammary carcinoma cell lines, and reduce cellular adhesion in mammary carcinoma cell lines. In this study, we provide molecular and functional evidence for the involvement of the enigmatic σ1 receptors in lipid raft modeling by σ1 receptor–mediated cholesterol alteration of lipid rafts in breast cancer cell lines. Cholesterol binds to cholesterol recognition domains in the COOH terminus of the σ1 receptor. This binding is blocked by σ receptor drugs because the cholesterol-binding domains form part of the σ receptor drug-binding site, mutations of which abolish cholesterol binding. Furthermore, we outline a hypothetical functional model to explain the myriad of biological processes, including cancer, in which these mysterious receptors are involved. The findings of this study provide a biological basis for the potential therapeutic applications of lipid raft cholesterol regulation in cancer therapy using σ receptor drugs. [Cancer Res 2007;67(23):11166–75]
Data from Heat Shock Protein B8, a Cyclin-Dependent Kinase–Independent Cyclin D1 Target Gene, Contributes to Its Effects on Radiation Sensitivity
Authors: Trent Sally , Yang Chuanwei , Li Cuiqi , Lynch Mary , Schmidt Emmett V.
Published: March 2024

Abstract
Overexpression of cyclin D1 is associated with many cancers, and its overexpression is especially associated with a poor prognosis in breast cancer. Paradoxically, cyclin D1 is known to enhance radiation sensitivity, a finding that has not yet been therapeutically exploited. Proposed cyclin D1 functions that could be involved in this effect include cyclin-dependent kinase (CDK)–dependent phosphorylation of retinoblastoma gene product (pRb), titration of p21/p27 complexes, and less well-characterized effects on gene expression. In this report, we sought to clarify the functions of cyclin D1 that might contribute to enhanced radiation sensitivity. Breast cancer cells stably overexpressing a cyclin D1 mutant (KE) that cannot interact with its CDK partners to phosphorylate pRb were as radiation sensitive as those expressing wild-type D1. Although cyclin D1 has been proposed to affect radiation sensitivity through interactions with p21, a cyclin D1 mutant defective for p21 interactions also increased radiation sensitivity. Cyclin D1 overexpression is generally confined to hormone receptor–positive breast cancers, wherein standard therapies include both radiation and hormonal therapies. Among several proposed CDK-independent cyclin D1 targets, we have identified heat shock protein B8 (HSPB8) as a target particularly associated with cyclin D1 and ER-positive tumors. We therefore evaluated its potential contribution to radiation sensitivity. Overexpression of HSPB8 markedly increased radiation sensitivity, and HSPB8 small interfering RNA blocked cyclin D1's enhancement of radiation sensitivity. Taken together, our results show that some of cyclin D1's effects on radiation sensitivity are CDK and p21 independent and identify HSPB8 as a candidate CDK-independent cyclin D1 target that can mediate its effects. [Cancer Res 2007;67(22):10774–81]
Data from Telomerase-Specific T-Cell Immunity in Breast Cancer: Effect of Vaccination on Tumor Immunosurveillance
Authors: Domchek Susan M. , Recio Adri , Mick Rosemarie , Clark Carolyn E. , Carpenter Erica L. , Fox Kevin R. , DeMichele Angela , Schuchter Lynn M. , Leibowitz Michael S. , Wexler Michael H. , Vance Barbara A. , Beatty Gregory L. , Veloso Elizabeth , Feldman Michael D. , Vonderheide Robert H.
Published: March 2024

Abstract
The human telomerase reverse transcriptase (hTERT) is nearly universally overexpressed in human cancer, contributes critically to oncogenesis, and is recognized by cytotoxic T cells that lyse tumors. CD8+ T cells specific for hTERT naturally occur in certain populations of cancer patients in remission, but it remains poorly understood whether such T cells could contribute to tumor immunosurveillance. To address this issue, we induced hTERT-specific T cells in vivo via peptide vaccination in 19 patients with metastatic breast cancer who otherwise had no measurable T-cell responses to hTERT at baseline. Tumor-infiltrating lymphocytes (TIL) were evident after, but not before vaccination, with 4% to 13% of postvaccine CD8+ TIL specific for the immunizing hTERT peptide. Induction of TIL manifested clinically with tumor site pain and pruritus and pathologically with alterations in the tumor microenvironment, featuring histiocytic accumulation and widespread tumor necrosis. hTERT-specific CD8+ T cells were also evident after vaccination in the peripheral blood of patients and exhibited effector functions in vitro including proliferation, IFN-γ production, and tumor lysis. An exploratory landmark analysis revealed that median overall survival was significantly longer in those patients who achieved an immune response to hTERT peptide compared with patients who did not. Immune response to a control cytomegalovirus peptide in the vaccine did not correlate with survival. These results suggest that hTERT-specific T cells could contribute to the immunosurveillance of breast cancer and suggest novel opportunities for both therapeutic and prophylactic vaccine strategies for cancer. [Cancer Res 2007;67(21):1–9]
Data from Frequent Loss of Brm Expression in Gastric Cancer Correlates with Histologic Features and Differentiation State
Authors: Yamamichi Nobutake , Inada Ken-ichi , Ichinose Masao , Yamamichi-Nishina Mitsue , Mizutani Taketoshi , Watanabe Hirotaka , Shiogama Kazuya , Fujishiro Mitsuhiro , Okazaki Takuya , Yahagi Naohisa , Haraguchi Takeshi , Fujita Shuji , Tsutsumi Yutaka , Omata Masao , Iba Hideo
Published: March 2024

Abstract
The mammalian SWI/SNF chromatin remodeling complex, an essential epigenetic regulator, contains either a single Brm or BRG1 molecule as its catalytic subunit. We observed frequent loss of Brm expression but not of BRG1 in human gastric cancer cell lines. Treatment with histone deacetylase inhibitor rescued Brm expression, indicating epigenetic regulation of this gene, and an RNA interference–based colony formation assay revealed antioncogenic properties of Brm. Brm immunostaining of 89 primary gastric cancers showed an obvious reduction in 60 cases (67%) and a severe decrease in 37 cases (42%). Loss of Brm is frequent in the major gastric cancer types (well- or moderately-differentiated tubular adenocarcinoma and poorly-differentiated adenocarcinoma) and positively correlates with the undifferentiated state. Among the minor gastric cancer types, Brm expression persists in signet-ring cell carcinoma and mucinous adenocarcinoma, but a marked decrease is observed in papillary adenocarcinoma. Intestinal metaplasia never shows decreased expression, indicating that Brm is a valid marker of gastric oncogenesis. In contrast, BRG1 is retained in most cases; a concomitant loss of BRG1 and Brm is rare in gastric cancer, contrary to other malignancies. We further show that Brm is required for villin expression, a definitive marker of intestinal metaplasia and differentiation. Via regulating such genes important for gut differentiation, Brm should play significant roles in determining the histologic features of gastric malignancy. [Cancer Res 2007;67(22):10727–35]
Data from RAD51 Up-regulation Bypasses BRCA1 Function and Is a Common Feature of BRCA1-Deficient Breast Tumors
Authors: Martin Richard W. , Orelli Brian J. , Yamazoe Mitsuyoshi , Minn Andy J. , Takeda Shunichi , Bishop Douglas K.
Published: March 2024

Abstract
The breast cancer susceptibility gene BRCA1 encodes a large protein thought to contribute to a variety of cellular processes, although the critical determinants of BRCA1-deficient tumorigenesis remain unclear. Given that BRCA1 is required for cell proliferation, suppressor mutations are believed to modify BRCA1 phenotypes and contribute to the etiology of BRCA1-deficient tumors. Here, we show that overexpression of the homologous recombinase RAD51 in a DT40 BRCA1Δ/Δ mutant rescues defects in proliferation, DNA damage survival, and homologous recombination (HR). In addition, epistasis analysis with BRCA1 and the DNA end-joining factor KU70 indicates that these factors operate independently of one another to repair double-strand breaks. Consistent with this genetic finding, cell synchronization studies show that the ability of BRCA1 to promote radioresistance is restricted to the late S and G2 phases of the cell cycle, as predicted for genes whose function is specific to homology-mediated repair rather than nonhomologous end-joining. Notably, retrospective analyses of microarray expression data reveal elevated expression of RAD51 and two of its late-acting cofactors, RAD54 and RAD51AP1, in BRCA1-deficient versus sporadic breast tumors. Taken together, our results indicate that up-regulation of HR provides a permissive genetic context for cells lacking BRCA1 function by circumventing its requirement in RAD51 subnuclear assembly. Furthermore, the data support a model in which enhanced HR activity contributes to the etiology of BRCA1-deficient tumors. [Cancer Res 2007;67(20):9658–65]
Data from Silibinin Sensitizes Human Glioma Cells to TRAIL-Mediated Apoptosis via DR5 Up-regulation and Down-regulation of c-FLIP and Survivin
Authors: Son Yong-gyu , Kim Eun Hee , Kim Jin Yeop , Kim Seung U. , Kwon Taeg Kyu , Yoon A-Rum , Yun Chae-Ok , Choi Kyeong Sook
Published: March 2024

Abstract
Silibinin, a flavonoid isolated from Silybum marianum, has been reported to have cancer chemopreventive and therapeutic effects. Here, we show that treatment with subtoxic doses of silibinin in combination with tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) induces rapid apoptosis in TRAIL-resistant glioma cells, but not in human astrocytes, suggesting that this combined treatment may offer an attractive strategy for safely treating gliomas. Although the proteolytic processing of procaspase-3 by TRAIL was partially blocked in glioma cells, cotreatment with silibinin efficiently recovered TRAIL-induced caspase activation in these cells. Silibinin treatment up-regulated DR5, a death receptor of TRAIL, in a transcription factor CHOP-dependent manner. Furthermore, treatment with silibinin down-regulated the protein levels of the antiapoptotic proteins FLIPL, FLIPS, and survivin through proteasome-mediated degradation. Taken together, our results show that the activity of silibinin to modulate multiple components in the death receptor–mediated apoptotic pathway is responsible for its ability to recover TRAIL sensitivity in TRAIL-resistant glioma cells. [Cancer Res 2007;67(17):8274–84]
Data from Molecular Basis for the Induction of an Angiogenesis Inhibitor, Thrombospondin-1, by 5-Fluorouracil
Authors: Zhao Hong-Ye , Ooyama Akio , Yamamoto Masatatsu , Ikeda Ryuji , Haraguchi Misako , Tabata Sho , Furukawa Tatsuhiko , Che Xiao-Fang , Zhang Shaoxuan , Oka Toshinori , Fukushima Masakazu , Nakagawa Masayuki , Ono Mayumi , Kuwano Michihiko , Akiyama Shin-ichi
Published: March 2024

Abstract
5-Fluorouracil (5-FU) is one of the most commonly used anticancer drugs in chemotherapy against various solid tumors. 5-FU dose-dependently increased the expression levels of intrinsic antiangiogenic factor thrombospondin-1 (TSP-1) in human colon carcinoma KM12C cells and human breast cancer MCF7 cells. We investigated the molecular basis for the induction of TSP-1 by 5-FU in KM12C cells. Promoter assays showed that the region with the Egr-1 binding site is critical for the induction of TSP-1 promoter activity by 5-FU. The binding of Egr-1 to the TSP-1 promoter was increased in KM12C cells treated with 5-FU. Immunofluorescence staining revealed that 5-FU significantly increased the level of Egr-1 in the nuclei of KM12C cells. The suppression of Egr-1 expression by small interfering RNA decreased the expression level of TSP-1. Furthermore, 5-FU induced the phosphorylation of p38 mitogen-activated protein kinase (MAPK) and heat shock protein 27 (HSP27). Blockade of the p38 MAPK pathway by SB203580 remarkably inhibited the phosphorylation of HSP27 induced by 5-FU and decreased the induction of Egr-1 and TSP-1 by 5-FU in KM12C cells. These findings suggest that the p38 MAPK pathway plays a crucial role in the induction of Egr-1 by 5-FU and that induced Egr-1 augments TSP-1 promoter activity, with the subsequent production of TSP-1 mRNA and protein. [Cancer Res 2008;68(17):7035–41]
Data from Systematic Urokinase-Activated Anthrax Toxin Therapy Produces Regressions of Subcutaneous Human Non–Small Cell Lung Tumor in Athymic Nude Mice
Authors: Su Yunpeng , Ortiz Janelle , Liu Shihui , Bugge Thomas H. , Singh Ravibhushan , Leppla Stephen H. , Frankel Arthur E.
Published: March 2024

Abstract
The novel recombinant anthrax toxin, PrAgU2/FP59, composed of the urokinase-activated protective antigen and a fusion protein of Pseudomonas exotoxin and lethal factor was tested for anti–lung cancer efficacy in an in vivo human tumor model. Male athymic nude mice (age 4–6 weeks) were inoculated s.c. with 10 million H1299 non–small cell lung cancer (NSCLC) cells in the left flank. When tumor volumes reached 200 mm3 (6–8 days), i.p. injection of 100 μL saline or different ratios and doses of PrAgU2/FP59 in 100 μL saline were given every 3 days for four doses and an additional dose at day 29. Animals were monitored twice daily and tumor measurements were made by calipers. The maximum tolerated doses of PrAgU2/FP59 differed dependent on the ratios of PrAgU2 to FP59 over the range of 3:1 to 25:1, respectively. At tolerated doses, tumor regressions were seen in all animals. Complete histologic remission lasting 60 days occurred in 30% of animals. PrAgU2/FP59 showed dramatic anti-NSCLC efficacy and warrants further clinical development for therapy of patients with advanced NSCLC. [Cancer Res 2007;67(7):3329–36]
Data from EphB4 Overexpression in B16 Melanoma Cells Affects Arterial-Venous Patterning in Tumor Angiogenesis
Authors: Huang Xiaoyong , Yamada Yoshihiro , Kidoya Hiroyasu , Naito Hisamichi , Nagahama Yumi , Kong Lingyu , Katoh Shin-Ya , Li Weng-lin , Ueno Masaya , Takakura Nobuyuki
Published: March 2024

Abstract
EphB4 receptor and its ligand ephrinB2 play an important role in vascular development during embryogenesis. In blood vessels, ephrinB2 is expressed in arterial endothelial cells (EC) and mesenchymal supporting cells, whereas EphB4 is only expressed in venous ECs. Previously, we reported that OP9 stromal cells, which support the development of both arterial and venous ECs, in which EphB4 was overexpressed, could inhibit ephrinB2-positive (ephrinB2+) EC development in an embryonic tissue organ culture system. Although the EphB4 receptor is expressed in a variety of tumor cells, its exact function in regulating tumor progression has not been clearly shown. Here we found that overexpression of EphB4 in B16 melanoma cells suppressed tumor growth in a s.c. transplantation tumor model. Histologic examination of these tumors revealed that EphB4 overexpression in B16 cells selectively suppressed arterial ephrinB2+ EC development. By coculturing ephrinB2-expressing SV40-transformed mouse ECs (SVEC) with EphB4-overexpressing B16 cells, we found that EphB4 induced the apoptosis of SVECs. However, ephrinB2 did not induce the apoptosis of EphB4-overexpressing B16 cells. Based on results from these experiments, we concluded that EphB4 overexpression in B16 tumor cells suppresses the survival of arterial ECs in tumors by a reverse signaling via ephrinB2. [Cancer Res 2007;67(20):9800–8]
Data from Vitamin E Analogues Inhibit Angiogenesis by Selective Induction of Apoptosis in Proliferating Endothelial Cells: The Role of Oxidative Stress
Authors: Dong Lan-Feng , Swettenham Emma , Eliasson Johanna , Wang Xiu-Fang , Gold Mikhal , Medunic Yasmine , Stantic Marina , Low Pauline , Prochazka Lubomir , Witting Paul K. , Turanek Jaroslav , Akporiaye Emmanuel T. , Ralph Stephen J. , Neuzil Jiri
Published: March 2024

Abstract
“Mitocans” from the vitamin E group of selective anticancer drugs, α-tocopheryl succinate (α-TOS) and its ether analogue α-TEA, triggered apoptosis in proliferating but not arrested endothelial cells. Angiogenic endothelial cells exposed to the vitamin E analogues, unlike their arrested counterparts, readily accumulated reactive oxygen species (ROS) by interfering with the mitochondrial redox chain and activating the intrinsic apoptotic pathway. The vitamin E analogues inhibited angiogenesis in vitro as assessed using the “wound-healing” and “tube-forming” models. Endothelial cells deficient in mitochondrial DNA (mtDNA) were resistant to the vitamin E analogues, both in ROS accumulation and apoptosis induction, maintaining their angiogenic potential. α-TOS inhibited angiogenesis in a mouse cancer model, as documented by ultrasound imaging. We conclude that vitamin E analogues selectively kill angiogenic endothelial cells, suppressing tumor growth, which has intriguing clinical implications. [Cancer Res 2007;67(24):11906–13]
Data from Gene Expression Profiling of Breast, Prostate, and Glioma Cells following Single versus Fractionated Doses of Radiation
Authors: Tsai Mong-Hsun , Cook John A. , Chandramouli Gadisetti V.R. , DeGraff William , Yan Hailing , Zhao Shuping , Coleman C. Norman , Mitchell James B. , Chuang Eric Y.
Published: March 2024

Abstract
Studies were conducted to determine whether gene expression profiles following a single dose of radiation would yield equivalent profiles following fractionated radiation in different tumor cell lines. MCF7 (breast), DU145 (prostate), and SF539 (gliosarcoma) cells were exposed to a total radiation dose of 10 Gy administered as a single dose (SD) or by daily multifractions (MF) of 5 × 2 Gy. Following radiation treatment, mRNA was isolated at 1, 4, 10, and 24 h and processed for cDNA microarray analysis. To determine the influence of the tumor microenvironment on gene expression, one cell type (DU145) was evaluated growing as a solid tumor in athymic nude mice for both radiation protocols. Unsupervised hierarchical cluster map analysis showed significant differences in gene expression profiles between SD and MF treatments for cells treated in vitro, with MF yielding a more robust induction compared with SD. Several genes were uniquely up-regulated by MF treatment, including multiple IFN-related genes (STAT1, G1P2, OAS1, OAS3, G1P3, IFITM1) and TGF-β–associated genes (EGR1, VEGF, THBS1, and TGFB2). DU145 cells grown in vivo exhibited a completely different set of genes induced by both SD and MF compared with the same cells exposed in vitro. The results of the study clearly show distinct differences in the molecular response of cells between SD and MF radiation exposures and show that the tumor microenvironment can significantly influence the pattern of gene expression after radiation exposures. [Cancer Res 2007;67(8):3845–52]
Data from A Polycomb Repression Signature in Metastatic Prostate Cancer Predicts Cancer Outcome
Authors: Yu Jindan , Yu Jianjun , Rhodes Daniel R. , Tomlins Scott A. , Cao Xuhong , Chen Guoan , Mehra Rohit , Wang Xiaoju , Ghosh Debashis , Shah Rajal B. , Varambally Sooryanarayana , Pienta Kenneth J. , Chinnaiyan Arul M.
Published: March 2024

Abstract
The Polycomb Group (PcG) protein EZH2 is a critical component of a multiprotein complex that methylates Lys27 of histone 3 (H3K27), which consequently leads to the repression of target gene expression. We have previously reported that EZH2 is overexpressed in metastatic prostate cancer and is a marker of aggressive diseases in clinically localized solid tumors. However, the global set of genes directly regulated by PcG in tumors is largely unknown, and thus how PcG mediates tumor progression remains unclear. Herein we mapped genome-wide H3K27 methylation in aggressive, disseminated human prostate cancer tissues. Integrative analysis revealed that a significant subset of these genes are also targets of PcG in embryonic stem cells, and their repression in tumors is associated with poor prognosis. By stepwise cross-validation, we developed a “Polycomb repression signature” composed of 14 direct targets of PcG in metastatic tumors. Notably, solid tumor subtypes in which this gene signature is repressed show poor clinical outcome in multiple microarray data sets of tumors including breast and prostate cancer. Taken together, our results show a fingerprint of PcG-mediated transcriptional repression in metastatic prostate cancer that is reminiscent of stem cells and associated with cancer progression. Therefore, PcG proteins play a central role in the epigenetic silencing of target genes and functionally link stem cells, metastasis, and cancer survival. [Cancer Res 2007;67(22):10657–63]
Data from High Levels of Heat Shock Protein Hsp72 in Cancer Cells Suppress Default Senescence Pathways
Authors: Yaglom Julia A. , Gabai Vladimir L. , Sherman Michael Y.
Published: March 2024

Abstract
The major heat shock protein Hsp72 is constitutively expressed in many tumor cell lines and biopsies, and its expression correlates with poor prognosis in several types of cancer. Hsp72 was suggested to play an important role in neoplastic transformation and tumor development. We addressed the role of Hsp72 in cancer cells by investigating the consequences of specific depletion of Hsp72 using small interfering RNA. Down-regulation of Hsp72 in certain cancer lines triggered cell senescence associated with activation and stabilization of p53 and induction of the cell cycle inhibitor p21. Effects of Hsp72 depletion on senescence and p53 did not result from a proteotoxic stress, DNA instability, or activation of ataxia-telangiectasia-mutated (ATM) and ATM- and Rad3-related pathways. Instead, depletion of Hsp72 reduced stability and activity of the p53 inhibitor Hdm2. In addition, Hsp72 depletion triggered a p53-independent senescence program through inhibitory phosphorylation and down-regulation of the cell cycle kinase Cdc2. Therefore, Hsp72 provides a selective advantage to cancer cells by suppressing default senescence via p53-dependent and p53-independent pathways. [Cancer Res 2007;67(5):2373–81]
Data from Coordinated Regulation of Pathways for Enhanced Cell Motility and Chemotaxis Is Conserved in Rat and Mouse Mammary Tumors
Authors: Wang Weigang , Wyckoff Jeffrey B. , Goswami Sumanta , Wang Yarong , Sidani Mazen , Segall Jeffrey E. , Condeelis John S.
Published: March 2024

Abstract
Correlating tumor cell behavior in vivo with patterns of gene expression has led to new insights into the microenvironment of tumor cells in the primary tumor. Until now, these studies have been done with cell line–derived tumors. In the current study, we have analyzed, in polyoma middle T oncogene (PyMT)–derived mammary tumors, tumor cell behavior and gene expression patterns of the invasive subpopulation of tumor cells by multiphoton-based intravital imaging and microarray-based expression profiling, respectively. Our results indicate that the patterns of cell behavior that contribute to invasion and metastasis in the PyMT tumor are similar to those seen previously in rat MTLn3 cell line–derived mammary tumors. The invasive tumor cells collected from PyMT mouse mammary tumors, like their counterparts from rat xenograft mammary tumors, are a population that is relatively nondividing and nonapoptotic but chemotherapy resistant and chemotactic. Changes in the expression of genes that occur uniquely in the invasive subpopulation of tumor cells in the PyMT mammary tumors that fall on the Arp2/3 complex, capping protein and cofilin pathways show a pattern like that seen previously in invasive tumor cells from the MTLn3 cell line–derived tumors. These changes predict an enhanced activity of the cofilin pathway, and this was confirmed in isolated invasive PyMT tumor cells. We conclude that changes in gene expression and their related changes in cell behavior, which were identified in the invasive tumor cells of cell line–derived tumors, are conserved in the invasive tumor cells of PyMT-derived mouse mammary tumors, although these tumor types have different genetic origins. [Cancer Res 2007;67(8):1–6]
Data from Carcinogen-Specific Gene Expression Profiles in Short-term Treated Eker and Wild-type Rats Indicative of Pathways Involved in Renal Tumorigenesis
Authors: Stemmer Kerstin , Ellinger-Ziegelbauer Heidrun , Ahr Hans-Juergen , Dietrich Daniel R.
Published: March 2024

Abstract
Eker rats heterozygous for a dominant germline mutation in the tuberous sclerosis 2 (Tsc2) tumor suppressor gene were used as a model to study renal carcinogenesis. Eker and corresponding wild-type rats were exposed to genotoxic aristolochic acid (AA) or non-genotoxic ochratoxin A (OTA) to elucidate early carcinogen-specific gene expression changes and to test whether Eker rats are more sensitive to carcinogen-induced changes in gene expression. Male Eker and wild-type rats were gavaged daily with AA (10 mg/kg body weight) or OTA (210 μg/kg body weight). After 1, 3, 7, and 14 days of exposure, renal histopathology, tubular cell proliferation, and Affymetrix gene expression profiles from renal cortex/outer medulla were analyzed. AA-treated Eker and wild-type rats were qualitatively comparable in all variables assessed, suggesting a Tsc2-independent mechanism of action. OTA treatment resulted in slightly increased cortical pathology and significantly elevated cell proliferation in both strains, although Eker rats were more sensitive. Deregulated genes involved in the phosphatidylinositol 3-kinase-AKT-Tsc2-mammalian target of rapamycin signaling, among other important genes prominent in tumorigenesis, in conjunction with the enhanced cell proliferation and presence of preneoplastic lesions suggested involvement of Tsc2 in OTA-mediated toxicity and carcinogenicity, especially as deregulation of genes involved in this pathway was more prominent in the Tsc2 mutant Eker rat. [Cancer Res 2007;67(9):4052–68]
Data from The Nuclear Matrix Protein, NRP/B, Enhances Nrf2-Mediated Oxidative Stress Responses in Breast Cancer Cells
Authors: Seng Seyha , Avraham Hava Karsenty , Jiang Shuxian , Yang Suping , Sekine Masayuki , Kimelman Noam , Li Huchun , Avraham Shalom
Published: March 2024

Abstract
The transcription factor NF-E2–related factor 2 (Nrf2) translocates into the nucleus and activates phase II genes encoding detoxification enzymes and antioxidant proteins, resulting in the protection of cells from oxidative insults. However, the involvement of Nrf2-mediated oxidative stress responses in breast cancer cells is largely unknown. Notably, during our study of the Nrf2 pathway in breast cancer cells, we observed that the nuclear matrix protein NRP/B was expressed and colocalized with Nrf2 in these cells, suggesting that NRP/B is involved in Nrf2-mediated oxidative stress responses. The expression level of NRP/B was variable in different breast cancer cells and breast cancer tissues, and was found to be localized in the nucleus. NRP/B expression was increased after exposure to the oxidative stress agent, hydrogen peroxide (H2O2), particularly in the highly aggressive MDA-MB-231 breast cancer cells. Association of NRP/B with Nrf2 in vitro and in vivo was observed in MDA-MB-231 breast cancer cells, and this association was up-regulated upon exposure to H2O2, but not to sodium nitroprusside, SIN-1, and DETA-NO. NRP/B also enhanced Nrf2-mediated NAD(P)H:quinine oxidoreductase 1 promoter activity. Thus, this study reveals that NRP/B enhances oxidative stress responses in breast cancer cells via the Nrf2 pathway, identifying a novel role of nuclear matrix protein(s) in oxidative stress responses. [Cancer Res 2007;67(18):8596–604]