bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wnt3a Growth Factor Induces Androgen Receptor-Mediated Transcription and Enhances Cell Growth in Human Prostate Cancer Cells
Authors: Verras Meletios , Brown Jeffrey , Li Xiaomeng , Nusse Roel , Sun Zijie 
Published: September 2005

Abstract
The Wnt signaling pathway plays a critical role in embryogenesis and tumorigenesis. However, biological roles of Wnt growth factors have not been fully characterized in prostate development and the pathogenesis of prostate cancer. In this study, we used Wnt3a-conditioned medium (Wnt3a-CM) and purified Wnt3a proteins to investigate whether there is a direct effect of Wnt3a on androgen receptor (AR)-mediated transcription and to determine its role in the growth of prostate cancer cells. We demonstrated that Wnt3a-CM either induces AR activity in the absence of androgens or enhances AR activity in the presence of low concentrations of androgens, whereas purified Wnt3a showed a pronounced effect in the presence of low concentrations of ligands. We also showed that Wnt3a-CM and the purified Wnt3a enhance the level of cytosolic and nuclear β-catenin, suggesting an involvement of β-catenin in this regulation. Moreover, treatment of LNCaP cells with Wnt3a-CM and purified Wnt3a significantly enhances cell growth in the absence of androgens. Our findings demonstrate that Wnt3a plays an important role in androgen-mediated transcription and cell growth. These results suggest a novel mechanism for the progression of prostate cancer.
Folate Is Associated with the Natural History of High-Risk Human Papillomaviruses
Authors: Piyathilake Chandrika J. , Henao Olga L. , Macaluso Maurizio , Cornwell Phillip E. , Meleth Sreelatha , Heimburger Douglas C. , Partridge Edward E. 
Published: September 2005

Abstract
Several micronutrients have been implicated in cervical carcinogenesis. However, their mode of action is still a matter of speculation. In particular, it is unclear whether certain nutrients reduce the probability of acquiring high-risk human papillomavirus (HPV) or whether they facilitate the clearance of high-risk HPV. We conducted a 24-month prospective follow-up study to test the hypothesis that systemic concentrations of folate are associated with the occurrence and duration of high-risk HPV infections after controlling for other micronutrients (vitamins B12, A, E, and C, total carotene) and known risk factors for high-risk HPV infections and cervical cancer. Circulating concentrations of these micronutrients and risk factors for cervical cancer were determined in a cohort of 345 women who were at risk of developing cervical intraepithelial neoplasia. Using the hybrid capture 2 (HC-2) assay, high-risk HPV status was evaluated at 6-month intervals up to 24 months. All women had at least three consecutive visit high-risk HPV test results. Higher folate status was inversely associated with becoming HC-2 test-positive [odds ratio (OR): 0.27; 95% confidence interval (CI), 0.08–0.91; P = 0.04]. Women with higher folate status were significantly less likely to be repeatedly HC-2 test-positive (OR: 0.33; 95% CI, 0.13–0.86; P = 0.02) and more likely to become test-negative during the study (OR: 2.50; 95% CI, 1.18–5.30; P = 0.02). To our knowledge, this is the first long-term prospective follow-up study reporting an independent protective role of higher folate status on several aspects of the natural history of high-risk HPV after controlling for known risk factors and other micronutrients. Improving folate status in subjects at risk of getting infected or already infected with high-risk HPV may have a beneficial impact in the prevention of cervical cancer.
Vδ1 T Lymphocytes from B-CLL Patients Recognize ULBP3 Expressed on Leukemic B Cells and Up-Regulated by
Trans
-Retinoic Acid
Authors: Poggi Alessandro , Venturino Claudia , Catellani Silvia , Clavio Marino , Miglino Maurizio , Gobbi Marco , Steinle Alexander , Ghia Paolo , Stella Stefania , Caligaris-Cappio Federico , Zocchi Maria Raffaella 
Published: September 2005

Abstract
We analyzed 38 untreated patients with chronic lymphocytic leukemia of B-cell type (B-CLL): 24 low-, 8 intermediate-, and 6 high-risk stage. In 15 patients (13 low risk and 2 intermediate risk), circulating Vδ1 T lymphocytes were significantly increased (100 to 300 cells/μL) compared with most intermediate, all high-risk stage, and 15 healthy donors (50 to 100 cells/μL). We studied these Vδ1 T lymphocytes and observed that they proliferated in vitro and produced tumor necrosis factor α or IFN-γ in response to autologous leukemic B cells but not to normal lymphocytes. However, they were unable to kill resting autologous B cells, which lack the MHC-related MIC-A antigen and express low levels of the UL16-binding protein (ULBP) 3 and undetectable levels of ULBP1, ULBP2, and ULBP4. All these molecules are reported ligands for the NKG2D receptor, which is expressed by γδ T cells and activates their cytolytic function. The Vδ1 T lymphocytes studied were able to lyse the ULBP3+ C1R B-cell line upon transfection with MIC-A. More importantly, they also lysed autologous B-CLL cells when transcription and expression of MIC-A or up-regulation of ULBP3 were achieved either by activation or by exposure to trans-retinoic acid. The NKG2D receptor expressed on Vδ1 T cells was involved in the recognition of B-CLL. Finally, in six patients with low numbers of circulating Vδ1 T cells and undetectable ULBP3, the disease progressed over 1 year, whereas no progression occurred in patients with high Vδ1 T lymphocytes and detectable/inducible ULBP3. These data suggest that Vδ1 T lymphocytes may play a role in limiting the progression of B-CLL.
Inhibition of Chk1 by CEP-3891 Accelerates Mitotic Nuclear Fragmentation in Response to Ionizing Radiation
Authors: Syljuåsen Randi G. , Sørensen Claus Storgaard , Nylandsted Jesper , Lukas Claudia , Lukas Jiri , Bartek Jiri 
Published: September 2005

Abstract
The human checkpoint kinase Chk1 has been suggested as a target for cancer treatment. Here, we show that a new inhibitor of Chk1 kinase, CEP-3891, efficiently abrogates both the ionizing radiation (IR)-induced S and G2 checkpoints. When the checkpoints were abrogated by CEP-3891, the majority (64%) of cells showed fragmented nuclei at 24 hours after IR (6 Gy). The formation of nuclear fragmentation in IR-treated human cancer cells was directly visualized by time-lapse video microscopy of U2-OS cells expressing a green fluorescent protein-tagged histone H2B protein. Nuclear fragmentation occurred as a result of defective chromosome segregation when irradiated cells entered their first mitosis, either prematurely without S and G2 checkpoint arrest in the presence of CEP-3891 or after a prolonged S and G2 checkpoint arrest in the absence of CEP-3891. The nuclear fragmentation was clearly distinguishable from apoptosis because caspase activity and nuclear condensation were not induced. Finally, CEP-3891 not only accelerated IR-induced nuclear fragmentation, it also increased the overall cell killing after IR as measured in clonogenic survival assays. These results demonstrate that transient Chk1 inhibition by CEP-3891 allows premature mitotic entry of irradiated cells, thereby leading to accelerated onset of mitotic nuclear fragmentation and increased cell death.
Androgen-Independent Prostate Cancer Is a Heterogeneous Group of Diseases
Authors: Shah Rajal B. , Mehra Rohit , Chinnaiyan Arul M. , Shen Ronglai , Ghosh Debashis , Zhou Ming , MacVicar Gary R. , Varambally Soorynarayana , Harwood Jason , Bismar Tarek A. , Kim Robert , Rubin Mark A. , Pienta Kenneth J. 
Published: September 2005

Abstract
Understanding the biology of prostate cancer metastasis has been limited by the lack of tissue for study. We studied the clinical data, distribution of prostate cancer involvement, morphology, immunophenotypes, and gene expression from 30 rapid autopsies of men who died of hormone-refractory prostate cancer. A tissue microarray was constructed and quantitatively evaluated for expression of prostate-specific antigen, androgen receptor, chromogranin, synaptophysin, MIB-1, and α-methylacylCoA-racemase markers. Hierarchical clustering of 16 rapid autopsy tumor samples was performed to evaluate the cDNA expression pattern associated with the morphology. Comparisons were made between patients as well as within the same patient. Metastatic hormone-refractory prostate cancer has a heterogeneous morphology, immunophenotype, and genotype, demonstrating that “metastatic disease” is a group of diseases even within the same patient. An appreciation of this heterogeneity is critical to evaluating diagnostic and prognostic biomarkers as well as to designing therapeutic targets for advanced disease.
Pten Loss Causes Hypertrophy and Increased Proliferation of Astrocytes
In vivo
Authors: Fraser Melissa M. , Zhu Xiaoyan , Kwon Chang-Hyuk , Uhlmann Erik J. , Gutmann David H. , Baker Suzanne J. 
Published: September 2005

Abstract
Somatic mutations of PTEN are found in many types of cancers including glioblastoma, the most malignant astrocytic tumor. PTEN mutation occurs in 25 to 40% of glioblastomas but is rarely observed in low-grade glial neoplasms. To determine the role of Pten in astrocytes and glial tumor formation, we inactivated Pten by a Cre-loxP approach with a GFAP-cre transgenic mouse that induced Cre-mediated recombination in astrocytes. Pten conditional knockout mice showed a striking progressive enlargement of the entire brain. Increased nuclear and soma size was observed in both astrocytes and neurons, which contributed in part to the increase in brain size. Pten-deficient astrocytes showed accelerated proliferation in vitro and aberrant ongoing proliferation in adult brains in vivo. In contrast, neurons lacking Pten did not show alterations in proliferation. This study shows cell-type dependent effects of Pten loss in the adult brain, including increased astrocyte proliferation that may render astroglial cells susceptible to neoplastic transformation or malignant progression.
Loss of Neural Cell Adhesion Molecule Induces Tumor Metastasis by Up-regulating Lymphangiogenesis
Authors: Crnic Ivana , Strittmatter Karin , Cavallaro Ugo , Kopfstein Lucie , Jussila Lotta , Alitalo Kari , Christofori Gerhard 
Published: September 2005

Abstract
Reduced expression of neural cell adhesion molecule (NCAM) has been implicated in the progression to tumor malignancy in cancer patients. Previously, we have shown that the loss of NCAM function causes the formation of lymph node metastasis in a transgenic mouse model of pancreatic β cell carcinogenesis (Rip1Tag2). Here we show that tumors of NCAM-deficient Rip1Tag2 transgenic mice exhibit up-regulated expression of the lymphangiogenic factors vascular endothelial growth factor (VEGF)-C and -D (17% in wild-type versus 60% in NCAM-deficient Rip1Tag2 mice) and, with it, increased lymphangiogenesis (0% in wild-type versus 19% in NCAM-deficient Rip1Tag2 mice). Repression of VEGF-C and -D function by adenoviral expression of a soluble form of their cognate receptor, VEGF receptor-3, results in reduced tumor lymphangiogenesis (56% versus 28% in control versus treated mice) and lymph node metastasis (36% versus 8% in control versus treated mice). The results indicate that the loss of NCAM function causes lymph node metastasis via VEGF-C- and VEGF-D-mediated lymphangiogenesis. These results also establish Rip1Tag2;NCAM-deficient mice as a unique model for stochastic, endogenous tumor lymphangiogenesis and lymph node metastasis in immunocompetent mice.
Cul4A Physically Associates with MDM2 and Participates in the Proteolysis of p53
Authors: Nag Alo , Bagchi Srilata , Raychaudhuri Pradip 
Published: September 2005

Abstract
The cullin 4A (Cul4A) gene is amplified and overexpressed in breast and hepatocellular carcinomas. Cul4A functions as an E3 ligase and participates in the proteolysis of several regulatory proteins through the ubiquitin-proteasome pathway. Here, we show that Cul4A associates with MDM2 and p53. Depletion of Cul4A leads to an accumulation of p53. Moreover, expression of Cul4A increases the decay-rate of p53 and delays the accumulation of p53 in response to DNA damage. Cul4A fails to increase the decay of p53 in mouse embryonic fibroblasts lacking MDM2. In addition, the Cul4A-mediated rapid decay of p53 is blocked by p19ARF. The results provide evidence for a role of Cul4A in the MDM2-mediated proteolysis of p53.
Androgenic Suppression of ATP-binding Cassette Transporter A1 Expression in LNCaP Human Prostate Cancer Cells
Authors: Fukuchi Junichi , Hiipakka Richard A. , Kokontis John M. , Hsu Stephen , Ko Andrew L. , Fitzgerald Michael L. , Liao Shutsung 
Published: September 2005

Abstract
Alteration of lipid metabolism is commonly observed in sex hormone-dependent cancer cells, yet its mechanistic involvement in cancer cell proliferation and progression is unclear. We have found that the expression of the cholesterol transporter, ATP-binding cassette transporter A1 (ABCA1), was 15- to 20-fold higher in androgen-dependent than in androgen-independent LNCaP human prostate cancer cells, indicating a possible relationship between the expression levels of ABCA1 and prostate cancer progression. On the basis of real-time quantitative PCR and Western blot analysis, expression of ABCA1 in androgen-dependent cells was inhibited by androgen. The antiandrogen Casodex blocked the effect of androgen, implicating the androgen receptor in regulation of ABCA1 expression by androgens. Using an ABCA1 promoter-reporter gene assay, androgenic suppression was observed at the transcriptional level in androgen-dependent but not in androgen-independent prostate cancer cells. ABCA1 appears to have a role in modulating cell proliferation because knockdown of ABCA1 expression by RNA interference in androgen-dependent cells increased their rate of proliferation. Therefore, a suppressive effect of androgen on ABCA1 expression may be one of the mechanisms by which androgens regulate proliferation in prostate cancer cells. Attenuated ABCA1 expression in androgen-independent cells thus may contribute, in part, to prostate cancer progression.
Natural Killer Cell-Mediated Killing of Freshly Isolated Neuroblastoma Cells
Authors: Castriconi Roberta , Dondero Alessandra , Corrias Maria Valeria , Lanino Edoardo , Pende Daniela , Moretta Lorenzo , Bottino Cristina , Moretta Alessandro 
Published: September 2005

Abstract
In the present study, we assessed the susceptibility of freshly isolated neuroblastoma cells to killing mediated by normal human natural killer (NK) cells and analyzed the receptor–ligand interactions that regulate this event. We show that killing of freshly isolated neuroblasts, similar to neuroblastoma cell lines, involves NKp46 and NKp30 (natural cytotoxicity receptors). However, freshly isolated neuroblasts were generally more resistant to NK-mediated lysis than conventional neuroblastoma cell lines. Moreover, a significant heterogeneity in susceptibility to lysis existed among neuroblastomas derived from different patients. Remarkably, susceptibility to lysis directly correlated with the surface expression, on neuroblasts, of poliovirus receptor [PVR (CD155)], a ligand for the DNAX accessory molecule-1 [DNAM-1 (CD226)] triggering receptor expressed by NK cells. Indeed, PVR-expressing neuroblastomas were efficiently killed by NK cells. Moreover, monoclonal antibody-mediated masking of either DNAM-1 (on NK cells) or PVR (on neuroblasts) resulted in strong inhibition of tumor cell lysis. Thus, assessment of the PVR surface levels may represent a novel useful criterion to predict the susceptibility/resistance of neuroblastomas to NK-mediated killing.
Elevated Flk1 (Vascular Endothelial Growth Factor Receptor 2) Signaling Mediates Enhanced Angiogenesis in β3-Integrin–Deficient Mice
Authors: Reynolds Andrew R. , Reynolds Louise E. , Nagel Tobi E. , Lively Julie C. , Robinson Stephen D. , Hicklin Daniel J. , Bodary Sarah C. , Hodivala-Dilke Kairbaan M. 
Published: September 2005

Abstract
Tumor growth, tumor angiogenesis, and vascular endothelial growth factor (VEGF)–specific angiogenesis are all enhanced in β3-integrin–null mice. Furthermore, endothelial cells isolated from β3-null mice show elevated levels of Flk1 (VEGF receptor 2) expression, suggesting that β3-integrin can control the amplitude of VEGF responses by controlling Flk1 levels or activity. We now show that Flk1 signaling is required for the enhanced tumor growth and angiogenesis seen in β3-null mice. Moreover, β3-null endothelial cells exhibit enhanced migration and proliferation in response to VEGF in vitro, and this phenotype requires Flk1 signaling. Upon VEGF stimulation, β3-null endothelial cells exhibit higher levels of phosphorylated Flk1 and extracellular-related kinases 1 and 2 than wild-type endothelial cells. Furthermore, signaling via ERK1/2 is required to mediate the elevated responses to VEGF observed in β3-null endothelial cells and aortic rings in vitro. These data confirm that VEGF signaling via Flk1 is enhanced in β3-integrin–deficient mice and suggests that this increase may mediate the enhanced angiogenesis and tumor growth observed in these mice in vivo.
A Novel Nuclear Protein, MGC5306 Interacts with DNA Polymerase β and Has a Potential Role in Cellular Phenotype
Authors: Wang Liming , Bhattacharyya Nandan , Chelsea Diane M. , Escobar Pedro F. , Banerjee Sipra 
Published: September 2005

Abstract
A novel protein MGC5306 has been identified in yeast–two-hybrid analysis by screening a HeLa cDNA library with a truncated DNA polymeraseβ (polβΔ) as bait. The polβΔ is expressed in various types of cancers. Co-immunoprecipitation–Western blot analysis confirms not only its interaction with polβΔ but also with wild-type polβ. Binding to polβ indicates potential function of MGC5306 in repair pathway. Transfection of cells with MGC5306-GFP and Western blot analysis with anti-MGC5306 antibody reveal its nuclear localization. MGC5306 is expressed in human carcinomas and tumor cell lines but not in normal tissues, suggesting MGC5306 is most likely involved in carcinogenesis. An antigrowth activity and modulations of cell cycle events are identified in cells expressing siRNAMGC5306.
Oral Consumption of Green Tea Polyphenols Inhibits Insulin-Like Growth Factor-I–Induced Signaling in an Autochthonous Mouse Model of Prostate Cancer
Authors: Adhami Vaqar Mustafa , Siddiqui Imtiaz Ahmad , Ahmad Nihal , Gupta Sanjay , Mukhtar Hasan 
Published: September 2005

AbstractWe earlier demonstrated that oral infusion of green tea polyphenols inhibits development and progression of prostate cancer in transgenic adenocarcinoma of the mouse prostate (TRAMP) model. Evidence indicates that elevated levels of IGF-I with concomitant lowering of IGF binding protein (IGFBP)-3 are associated with increased risk for prostate cancer development and progression. In this study, we examined the role of IGF/IGFBP-3 signaling and its downstream and other associated events during chemoprevention of prostate cancer by green tea polyphenols in TRAMP mice. Our data demonstrated an increase in the levels of IGF-I, phosphatidylinositol 3′-kinase, phosphorylated Akt (Thr-308), and extracellular signal-regulated kinase 1/2 with concomitant decrease in IGFBP-3 in dorso-lateral prostate of TRAMP mice during the course of cancer progression, i.e., as a function of age. Continuous green tea polyphenol infusion for 24 weeks to these mice resulted in substantial reduction in the levels of IGF-I and significant increase in the levels of IGFBP-3 in the dorso-lateral prostate. This modulation of IGF/IGFBP-3 was found to be associated with an inhibition of protein expression of phosphatidylinositol 3′-kinase, phosphorylated forms of Akt (Thr-308) and extracellular signal-regulated kinase 1/2. Furthermore, green tea polyphenol infusion resulted in marked inhibition of markers of angiogenesis and metastasis most notably vascular endothelial growth factor, urokinase plasminogen activator, and matrix metalloproteinases 2 and 9. Based on our data, we suggest that IGF-I/IGFBP-3 signaling pathway is a prime pathway for green tea polyphenol-mediated inhibition of prostate cancer that limits the progression of cancer through inhibition of angiogenesis and metastasis.
Combined Total Genome Loss of Heterozygosity Scan of Breast Cancer Stroma and Epithelium Reveals Multiplicity of Stromal Targets
Authors: Fukino Koichi , Shen Lei , Matsumoto Satoshi , Morrison Carl D. , Mutter George L. , Eng Charis 
Published: September 2005

Abstract
Recent breast cancer studies have highlighted the importance of interactions between cancer epithelium and tumor stroma. Recently, the focus of solid tumor investigations has shifted from mutations in carcinomatous epithelium to disturbances of tissue organization in cancer. The genetic basis of this microenvironment, however, remains to be clarified. To begin to resolve this problem, a total genome loss of heterozygosity (LOH) scan was done on epithelial and stromal DNA from 134 sporadic invasive breast carcinomas. In addition to detecting more frequent LOH at three loci in stroma than in epithelium, we found strong evidence that LOH frequencies were significantly elevated in specific regions of each chromosome. We detected 57 markers, which were preferentially lost either in stroma (n = 38) or epithelium (n = 19), relative to the background LOH frequencies on their respective chromosomes. This multiplicity of stromal cell LOH, and hence loss of genetic material, provides a possible mechanism for interpatient variation in host-stromal response to invading adenocarcinoma cells. This is consistent with a model in which initial, random LOH occurs equally among epithelium and stroma, but subsequent clonal selection is driven by factors, which appear to be distinctly different between malignant epithelial and surrounding stromal cells. Genetic alterations in stroma did not mimic those in epithelium, but they could play a different and parallel role in carcinogenesis and tumor progression, probably by modifying some features specific to breast cancer.
Mutation of the
PIK3CA
Gene in Ovarian and Breast Cancer
Authors: Campbell Ian G. , Russell Sarah E. , Choong David Y. H. , Montgomery Karen G. , Ciavarella Marianne L. , Hooi Christine S. F. , Cristiano Briony E. , Pearson Richard B. , Phillips Wayne A. 
Published: September 2005

Abstract
Phosphatidylinositol 3′-kinases are lipid kinases with important roles in neoplasia. Recently, a very high frequency of somatic mutations in PIK3CA has been reported among a large series of colorectal cancers. However, the relevance of PIK3CA mutation in other cancer types remains unclear because of the limited number of tumors investigated. We have screened a total of 284 primary human tumors for mutations in all coding exons of PIK3CA using a combination of single stranded conformational polymorphism and denaturing high-performance liquid chromatography analysis. Among 70 primary breast cancers, 40% (28 of 70) harbored mutations in PIK3CA, making it the most common mutation described to date in this cancer type. Mutations were not associated with histologic subtype, estrogen receptor status, grade or presence of tumor in lymph nodes. Among the primary epithelial ovarian cancers only 11 of 167 (6.6%) contain somatic mutations, but there was a clear histologic subtype bias in their distribution. Only 2 of 88 (2.3%) of serous carcinomas had PIK3CA mutations compared with 8 of 40 (20.0%) endometrioid and clear cell cancers, which was highly significant (P = 0.001). In contrast, PIK3CA gene amplification (&gt;7-fold) was common among all histologic subtypes (24.5%) and was inversely associated with the presence of mutations. Overall, PIK3CA mutation or gene amplification was detected in 30.5% of all ovarian cancers and 45% of the endometrioid and clear cell subtypes. Our study is the first direct evidence that PIK3CA is an oncogene in ovarian cancer and greatly extends recent findings in breast cancer.