bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemoprevention of Human Prostate Cancer by Oral Administration of Green Tea Catechins in Volunteers with High-Grade Prostate Intraepithelial Neoplasia: A Preliminary Report from a One-Year Proof-of-Principle Study
Authors: Bettuzzi Saverio , Brausi Maurizio , Rizzi Federica , Castagnetti Giovanni , Peracchia Giancarlo , Corti Arnaldo 
Published: January 2006

Abstract
Green tea catechins (GTCs) proved to be effective in inhibiting cancer growth in several experimental models. Recent studies showed that 30% of men with high-grade prostate intraepithelial neoplasia (HG-PIN) would develop prostate cancer (CaP) within 1 year after repeated biopsy. This prompted us to do a proof-of-principle clinical trial to assess the safety and efficacy of GTCs for the chemoprevention of CaP in HG-PIN volunteers. The purity and content of GTCs preparations were assessed by high-performance liquid chromatography [(−)-epigallocathechin, 5.5%; (−)-epicatechin, 12.24%; (−)-epigallocatechin-3-gallate, 51.88%; (−)-epicatechin-3-gallate, 6.12%; total GTCs, 75.7%; caffeine, &lt;1%]. Sixty volunteers with HG-PIN, who were made aware of the study details, agreed to sign an informed consent form and were enrolled in this double-blind, placebo-controlled study. Daily treatment consisted of three GTCs capsules, 200 mg each (total 600 mg/d). After 1 year, only one tumor was diagnosed among the 30 GTCs-treated men (incidence, ∼3%), whereas nine cancers were found among the 30 placebo-treated men (incidence, 30%). Total prostate-specific antigen did not change significantly between the two arms, but GTCs-treated men showed values constantly lower with respect to placebo-treated ones. International Prostate Symptom Score and quality of life scores of GTCs-treated men with coexistent benign prostate hyperplasia improved, reaching statistical significance in the case of International Prostate Symptom Scores. No significant side effects or adverse effects were documented. To our knowledge, this is the first study showing that GTCs are safe and very effective for treating premalignant lesions before CaP develops. As a secondary observation, administration of GTCs also reduced lower urinary tract symptoms, suggesting that these compounds might also be of help for treating the symptoms of benign prostate hyperplasia. (Cancer Res 2006; 66(2): 1234-40)
Angiopoietin 2 Induces Glioma Cell Invasion by Stimulating Matrix Metalloprotease 2 Expression through the αvβ1 Integrin and Focal Adhesion Kinase Signaling Pathway
Authors: Hu Bo , Jarzynka Michael J. , Guo Ping , Imanishi Yorihisha , Schlaepfer David D. , Cheng Shi-Yuan 
Published: January 2006

Abstract
Accumulating evidence reveals a significant correlation between angiopoietin 2 (Ang2) expression and tumor invasion and metastasis in various human cancers, but the major focus of recent studies has been on the angiogenic effects of Ang2. We recently reported that Ang2-stimulated glioma cell invasion results from the up-regulation and activation of matrix metalloprotease 2 (MMP-2) in tumor cells. In this study, we identify a novel mechanism by which Ang2 stimulates MMP-2 expression leading to glioma cell invasion. We show that Ang2 interacts with αvβ1 integrin in Tie2-deficient human glioma cells, activating focal adhesion kinase (FAK), p130Cas, extracellular signal–regulated protein kinase (ERK) 1/2, and c-jun NH2-terminal kinase (JNK) and substantially enhancing MMP-2 expression and secretion. The Ang2/αvβ1 integrin signaling pathway was attenuated by functional inhibition of β1 and αv integrins, FAK, p130Cas, ERK1/2, and JNK. Furthermore, expression of a negative regulator of FAK, FAK-related nonkinase, by U87MG/Ang2–expressing glioma xenografts suppressed Ang2-induced MMP-2 expression and glioma cell infiltration in the murine brain. These data establish a functional link between Ang2 interaction with αvβ1 integrin and glioma cell invasion through the FAK/p130Cas/ERK1/2 and JNK-mediated signaling pathway. (Cancer Res 2006; 66(2): 775-83)
Differential Requirement for DNA Methyltransferase 1 in Maintaining Human Cancer Cell Gene Promoter Hypermethylation
Authors: Ting Angela H. , Jair Kam-wing , Schuebel Kornel E. , Baylin Stephen B. 
Published: January 2006

Abstract
Previous work has shown that DNA hypermethylation of tumor suppressor genes in colorectal cancer cells may be maintained in the absence of the major mammalian methyltransferase, DNA methyltransferase 1 (DNMT1). In an effort to dissect the dependency on DNMT1 to maintain such hypermethylation in different cancer types, we performed a systematic analysis of depletion of DNMT1 in colorectal (SW48), bladder (T24), and breast (T47D) cancer cells by DNMT1-specific small hairpin RNA (shRNA) targeting. We show that although DNMT1-deficient SW48 and T24 cells exhibited no observable growth defects and were able to maintain promoter hypermethylation, DNMT1-deficient T47D breast cells failed to form comparable numbers of colonies when stably selected for the incorporation of the DNMT1-specific shRNA expression vector, suggesting a growth defect with reduced levels of DNMT1. Further treatment of T47D cells with transient transfection of small interfering RNA targeting DNMT1 revealed that severely DNMT1-deficient T47D cells could not fully maintain promoter hypermethylation, and gene silencing was partially reversed at two of the three assayed loci. These observations suggest that human cancer cells may differ in their reliance on DNMT1 for maintaining DNA methylation. (Cancer Res 2006; 66(2): 729-35)
PTEN Autoregulates Its Expression by Stabilization of p53 in a Phosphatase-Independent Manner
Authors: Tang Yufang , Eng Charis 
Published: January 2006

Abstract
PTEN (phosphatase and tensin homologue, deleted on chromosome 10) is a tumor suppressor with dual phosphatase activity and mutations of its gene, PTEN, have been associated with many sporadic cancers and heritable neoplasia syndromes, including Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome. However, accumulating evidence now shows that PTEN may have novel functions other than as a phosphatase. In the present study, we show that PTEN is able to autoregulate its expression through the stabilization of another tumor suppressor p53. We further show that PTEN enhances p53 transactivation, a relationship that requires the interaction between PTEN and p53 and is PTEN phosphatase independent. We show that cell lines from Cowden syndrome and Bannayan-Riley-Ruvalcaba syndrome patients with germ line PTEN promoter mutations in the vicinity of the p53-binding motifs have altered p53 regulation. This seems to be due to reduced PTEN stability and decreased PTEN-p53 interactions. Our data provide clues to better understand the regulation of PTEN expression and the possible mechanisms of the pathogenesis of the subset of Cowden syndrome individuals with germ line promoter variation and who lack mutations in the PTEN coding region and splice sites. Importantly, this mechanism also holds for those sporadic tumors that lack intragenic mutations but have hemizygous deletion of PTEN, which includes the promoter region as manifested by loss-of-heterozygosity of 10q markers. The importance of our observations is underlined by the broad spectrum of neoplasias that harbor somatic PTEN or p53 alterations, or both. (Cancer Res 2006; 66(2): 736-42)
TheIn vivoExpansion Rate of Properly Stimulated Transferred CD8+ T Cells Exceeds That of an Aggressively Growing Mouse Tumor
Authors: Hwang Leroy N. , Yu Zhiya , Palmer Douglas C. , Restifo Nicholas P. 
Published: January 2006

AbstractIt has been hypothesized that rapidly dividing tumor cells can outpace adoptively transferred antitumor lymphocytes when tumors are large. However, this hypothesis is at odds with clinical observations indicating that bulky tumors can be destroyed by small numbers of adoptively transferred antitumor T cells. We sought to measure the relative growth rates of T cells and tumor cells in a model using transgenic CD8+ T cells specific for the gp10025-33 H-2Db epitope (called pmel-1) to treat large, well-established s.c. B16 melanoma. We tested the effect of the immunization using an altered peptide ligand vaccine alone or in combination with interleukin-2 (IL-2) by analyzing the kinetics of T-cell expansion using direct enumeration. We found that pmel-1 T cells proliferated explosively during a 5-day period following transfer. Calculations from net changes in population suggest that, at the peak of cell division, pmel-1 T cells divide at a rate of 5.3 hours per cell division, which was much faster than B16 tumor cells during optimal growth (24.9 hours per cell division). These results clearly indicate that the notion of a kinetic “race” between the tumor and the lymphocyte is no contest when adoptively transferred cells are stimulated with immunization and IL-2. When appropriately stimulated, tumor-reactive T-cell expansion can far exceed the growth of even an aggressively growing mouse tumor. (Cancer Res 2006; 66(2): 1132-8)
The Gene Expression Program of Prostate Fibroblast Senescence Modulates Neoplastic Epithelial Cell Proliferation through Paracrine Mechanisms
Authors: Bavik Claes , Coleman Ilsa , Dean James P. , Knudsen Beatrice , Plymate Steven , Nelson Peter S. 
Published: January 2006

Abstract
The greatest risk factor for developing carcinoma of the prostate is advanced age. Potential molecular and physiologic contributors to the frequency of cancer occurrence in older individuals include the accumulation of somatic mutations through defects in genome maintenance, epigenetic gene silencing, oxidative stress, loss of immune surveillance, telomere dysfunction, chronic inflammation, and alterations in tissue microenvironment. In this context, the process of prostate carcinogenesis can be influenced through interactions between intrinsic cellular alterations and the extrinsic microenvironment and macroenvironment, both of which change substantially as a consequence of aging. In this study, we sought to characterize the molecular alterations that occur during the process of prostate fibroblast senescence to identify factors in the aged tissue microenvironment capable of promoting the proliferation and potentially the neoplastic progression of prostate epithelium. We evaluated three mechanisms leading to cell senescence: oxidative stress, DNA damage, and replicative exhaustion. We identified a consistent program of gene expression that includes a subset of paracrine factors capable of influencing adjacent prostate epithelial growth. Both direct coculture and conditioned medium from senescent prostate fibroblasts stimulated epithelial cell proliferation, 3-fold and 2-fold, respectively. The paracrine-acting proteins fibroblast growth factor 7, hepatocyte growth factor, and amphiregulin (AREG) were elevated in the extracellular environment of senescent prostate fibroblasts. Exogenous AREG alone stimulated prostate epithelial cell growth, and neutralizing antibodies and small interfering RNA targeting AREG attenuated, but did not completely abrogate the growth-promoting effects of senescent fibroblast conditioned medium. These results support the concept that aging-related changes in the prostate microenvironment may contribute to the progression of prostate neoplasia. (Cancer Res 2006; 66(2): 794-802)
Dietary Soy Isoflavones Inhibit Estrogen Effects in the Postmenopausal Breast
Authors: Wood Charles E. , Register Thomas C. , Franke Adrian A. , Anthony Mary S. , Cline J. Mark 
Published: January 2006

Abstract
Soy isoflavones are promising dietary agents for prevention of breast cancer. Isoflavones bind estrogen receptors (ER) and may variably act as either estrogen agonists or antagonists depending on the estrogen environment. In this study, we used a postmenopausal primate model to evaluate interactive effects of dietary soy isoflavones and estrogen on risk markers for breast cancer. The experiment followed a randomized factorial design in which 31 ovariectomized adult female cynomolgus monkeys were divided into social groups of three to four animals each and rotated through eight different diets containing the human equivalent of 0, 60, 120, or 240 mg/d soy isoflavones with a dose of oral micronized 17β-estradiol (E2) corresponding to either a low (0.09 mg/d) or a high (0.5 mg/d) postmenopausal estrogen environment. Treatment periods lasted 4 months with a 1-month washout period between diets. The highest isoflavone dose resulted in significantly lower breast proliferation and uterine size in the high-estrogen environment. These effects were accompanied by divergent changes in breast markers of ER activation in which pS2 expression was significantly lower and progesterone receptor expression was significantly higher following the 240 mg isoflavone dose. All isoflavone doses resulted in lower serum estrone and E2 concentrations in the high-estrogen environment. In contrast, isoflavone treatment had no significant estrogen agonist effects and minimal antagonistic effects in the lower-estrogen environment. These findings show that in the presence of estrogen higher doses of dietary soy isoflavones may alter ER signaling and induce selective antagonistic effects in the breast. (Cancer Res 2006; 66(2): 1241-9)
Radiofrequency Thermal Ablation of Hepatocellular Carcinoma Liver Nodules Can Activate and Enhance Tumor-Specific T-Cell Responses
Authors: Zerbini Alessandro , Pilli Massimo , Penna Amalia , Pelosi Guido , Schianchi Claudia , Molinari Atim , Schivazappa Simona , Zibera Carlo , Fagnoni Francesco F. , Ferrari Carlo , Missale Gabriele 
Published: January 2006

Abstract
Radiofrequency thermal ablation (RFA) destroys tumoral tissue generating a local necrosis followed by marked inflammatory response with a dense T-cell infiltrate. In this study, we tested whether hepatocellular carcinoma thermal ablation can induce or enhance T-cell responses specific for hepatocellular carcinoma–associated antigens. Peripheral blood mononuclear cells derived from 20 patients with hepatocellular carcinoma were stimulated before and a month after RFA treatment with autologous hepatocellular carcinoma–derived protein lysates obtained before and immediately after RFA treatment. The effect of thermal ablation on memory T-cell responses to recall antigens [tetanus toxoid, protein purified derivative (PPD), Escherichia coli] was also assessed. T-cell reactivity was analyzed in an IFN-γ enzyme-linked immunospot assay and by intracellular IFN-γ staining. Treatment was followed by a significant increase of patients responsive either to tumor antigens derived from both the untreated hepatocellular carcinoma tissue (P &lt; 0.05) and the necrotic tumor (P &lt; 0.01) and by a higher frequency of circulating tumor-specific T cells. T-cell responses to recall antigens were also significantly augmented. Phenotypic analysis of circulating T and natural killer cells showed an increased expression of activation and cytotoxic surface markers. However, tumor-specific T-cell responses were not associated with protection from hepatocellular carcinoma relapse. Evidence of tumor immune escape was provided in one patient by the evidence that a new nodule of hepatocellular carcinoma recurrence was not recognized by T cells obtained at the time of RFA. In conclusion, RFA treatment generates the local conditions for activating the tumor-specific T-cell response. Although this effect is not sufficient for controlling hepatocellular carcinoma, it may represent the basis for the development of an adjuvant immunotherapy in patients undergoing RFA for primary and secondary liver tumors. (Cancer Res 2006; 66(2): 1139-46)
Tumor Cells Transduced with the MHC Class II Transactivator and CD80 Activate Tumor-Specific CD4+ T Cells Whether or Not They Are Silenced for Invariant Chain
Authors: Thompson James A. , Dissanayake Samudra K. , Ksander Bruce R. , Knutson Keith L. , Disis Mary L. , Ostrand-Rosenberg Suzanne 
Published: January 2006

AbstractThe specificity and potency of the immune system make immunotherapy a potential strategy for the treatment of cancer. To exploit this potential, we have developed cell-based cancer vaccines consisting of tumor cells expressing syngeneic MHC class II and costimulatory molecules. The vaccines mediate tumor regression in mice and activate human CD4+ T cells in vitro. Previous vaccines were generated by transducing MHC II negative tumor cells with a single HLA-DR allele. Because expression of multiple MHC II alleles would facilitate presentation of a broader repertoire of tumor antigens, we have now transduced tumor cells with the MHC class II transactivator (CIITA), a regulatory gene that coordinately increases expression of all MHC II alleles. Previous studies in mice indicated that coexpression of the MHC II accessory molecule invariant chain (Ii) inhibited presentation of endogenously synthesized tumor antigens and reduced vaccine efficacy. To determine if Ii expression affects presentation of MHC class II–restricted endogenously synthesized tumor antigens in human tumor cells, HLA-DR-MCF10 breast cancer cells were transduced with the CIITA, CD80 costimulatory molecule gene, and with or without small interfering RNAs (siRNA) specific for Ii. Ii expression is silenced &gt;95% in CIITA/CD80/siRNA transductants; down-regulation of Ii does not affect HLA-DR expression or stability; and Ii+ and Ii− transductants activate human CD4+ T cells to DRB1*0701-restricted HER-2/neu epitopes. Therefore, tumor cells transduced with the CIITA, CD80, and with or without Ii siRNA present endogenously synthesized tumor antigens and are potential vaccines for activating tumor-specific CD4+ T cells. (Cancer Res 2006; 66(2): 1147-54)
Effect of Adenovirus-Mediated Heat Shock Protein Expression and Oncolysis in Combination with Low-Dose Cyclophosphamide Treatment on Antitumor Immune Responses
Authors: Di Paolo Nelson C. , Tuve Sebastian , Ni Shaoheng , Hellström Karl Erik , Hellström Ingegerd , Lieber André 
Published: January 2006

AbstractHeat shock proteins such as gp96 have the ability to chaperone peptides and activate antigen-presenting cells. In this study, we tested whether adenovirus-mediated overexpression of secreted or membrane-associated forms of gp96 in tumor cells would stimulate an antitumor immune response. Studies were carried out in C57Bl/6 mice bearing aggressively growing s.c. tumors derived from syngeneic TC-1 cells, a cell line that expresses HPV16 E6 and E7 proteins. We found that secreted gp96 can induce protective and therapeutic antitumor immune responses. Our data also indicate that the antitumor effect of sgp96 expression seems to be limited by the induction of suppressive regulatory T cells (Treg). TC-1 tumor transplantation increased the number of splenic and tumor-infiltrating Tregs. Importantly, treatment of mice with low-dose cyclophosphamide decreased the number of Tregs and enhanced the immunostimulatory effect of sgp96 expression. We also tested whether an oncolytic vector (Ad.IR-E1A/TRAIL), that is able to induce tumor cell apoptosis and, potentially, release cryptic tumor epitopes in immunogenic form, could stimulate antitumor immune responses. Although tumor cells infected ex vivo with Ad.IR-E1A/TRAIL had no antitumor effect when used as a vaccine alone, the additional treatment with low-dose cyclophosphamide resulted in the elimination of pre-established tumors. This study gives a rationale for testing approaches that suppress Tregs in combination with oncolytic or immunostimulatory vectors. (Cancer Res 2006; 66(2): 960-9)
Targeting Cell-Impermeable Prodrug Activation to Tumor Microenvironment Eradicates Multiple Drug-Resistant Neoplasms
Authors: Wu Wenyuan , Luo Yunping , Sun Chengzao , Liu Yuan , Kuo Paul , Varga Janos , Xiang Rong , Reisfeld Ralph , Janda Kim D. , Edgington Thomas S. , Liu Cheng 
Published: January 2006

AbstractThe tumor microenvironment is notably enriched with a broad spectrum of proteases. The proteolytic specificities of peptide substrates provide modular chemical tools for the rational design of cell-impermeable prodrugs that are specifically activated by proteases extracellularly in the tumor microenvironment. Targeting cell-impermeable prodrug activation to tumor microenvironment will significantly reduce drug toxicity to normal tissues. The activated prodrug attacks both tumor and stroma cells through a “bystander effect” without selectively deleting target-producing cells, therefore further minimizing resistance and toxicity. Here, we showed that legumain, the only asparaginyl endopeptidase of the mammalian genome, is highly expressed by neoplastic, stromal, and endothelial cells in solid tumors. Legumain is present extracellularly in the tumor microenvironment, associated with matrix as well as cell surfaces and functional locally in the reduced pH of the tumor microenvironment. A novel legumain-activated, cell-impermeable doxorubicin prodrug LEG-3 was designed to be activated exclusively in the tumor microenvironment. Upon administration, there is a profound increase of the end-product doxorubicin in nuclei of cells in tumors but little in other tissues. This tumor microenvironment–activated prodrug completely arrested growth of a variety of neoplasms, including multidrug-resistant tumor in vivo and significantly extended survival without evidence of myelosuppression or cardiac toxicity. The tumor microenvironment–activated prodrug design can be extended to other proteases and chemotherapeutic compounds and provides new potentials for the rational development of more effective functionally targeted cancer therapeutics. (Cancer Res 2006; 66(2): 970-80)
Induction of Metastasis by S100P in a Rat Mammary Model and Its Association with Poor Survival of Breast Cancer Patients
Authors: Wang Guozheng , Platt-Higgins Angela , Carroll Joe , de Silva Rudland Suzete , Winstanley John , Barraclough Roger , Rudland Philip S. 
Published: January 2006

Abstract
S100P, an EF-hand calcium-binding protein, has been reported to be associated with the progression of many types of cancers. Transfection of an expression vector for S100P into a benign, nonmetastatic rat mammary cell line causes a 4- to 6-fold increase in its level in all four transformant cell clones. When the resultant transformant cell lines are introduced in turn into the mammary fat pads of syngeneic Furth-Wistar rats, there is a significant 3-fold increase in local muscle invasion and a significant induction of metastasis in 64% to 75% of tumor-bearing animals. In a group of 303 breast cancer patients followed for up to 20 years, antibodies to S100P immunocytochemically stain 161 primary tumors. Survival of patients with S100P-positive carcinomas is significantly worse by about 7-fold than for those with negatively stained carcinomas. There is also a significant association between the class level of immunocytochemical staining of the carcinoma cells and decreased patient survival. Positive staining for S100P is significantly associated with that for two other metastasis-inducing proteins, S100A4 and osteopontin. Patients with tumors that stained positively for both S100P and S100A4 have a significantly reduced survival of 1.1% over patients with either S100 protein alone. Multivariate regression analysis identifies S100P, S100A4, and osteopontin as the most significant independent indicators of death in this group of patients. These results suggest that stratification of patients into groups according to expression of multiple metastasis-inducing proteins may lead to a more accurate prediction of patient survival. (Cancer Res 2006; 66(2): 1199-207)