bluuebunny/crossref_metadata_2025 huggingface dataset:
Nitric oxide stimulates COX-2 expression in cultured collecting duct cells through MAP kinases and superoxide but not cGMP
Authors: Yang Tianxin , Zhang Aihua , Pasumarthy Anita , Zhang Lihong , Warnock Zachary , Schnermann Jurgen B.
Published: May 2006

Collecting ducts are a major site of renal production and action of both prostaglandins and nitric oxide. Experiments were undertaken to examine whether nitric oxide regulates cyclooxygenase (COX)-2 expression and PGE2release in cultured collecting duct cells. In mIMCD-K2 cells, sodium nitroprusside (SNP) in the 50- to 800-μM range induced a marked dose- and time-dependent increase in COX-2 protein levels, determined by immunoblotting, and the induction was detectable at 4 h. This was preceded by induction of COX-2 mRNA as determined by real-time-RT-PCR. The COX-2 induction was accompanied by a significant rise in PGE2release as determined by enzyme immunoassay. S-nitroso- N-acetylpenicillamine (SNAP) had a similar stimulatory effect on COX-2 expression and PGE2release. 8-bromo-cGMP (200 μM) had no effect on COX-2 expression. The SNP-stimulated COX-2 expression was not affected by the guanylyl cyclase inhibitor methylene blue or the protein kinase G inhibitor KT-5823 (2.0 μM). In contrast, the SNP-stimulated COX-2 expression was significantly reduced by either the Erk1/2 inhibitor PD-98059 or the P38 inhibitor SB-203580 and was abolished by combination of the two kinase inhibitors. The stimulation was also significantly blocked by the SOD mimetic tempol. Thus we conclude that NO stimulates COX-2 expression in collecting duct cells through mechanisms involving MAP kinase and superoxide, but not cGMP.
Role of a tyrosine kinase in the CO2-induced stimulation of HCO3−reabsorption by rabbit S2 proximal tubules
Authors: Zhou Yuehan , Bouyer Patrice , Boron Walter F.
Published: May 2006

A previous study demonstrated that proximal tubule cells regulate HCO3−reabsorption by sensing acute changes in basolateral CO2concentration, suggesting that there is some sort of CO2sensor at or near the basolateral membrane (Zhou Y, Zhao J, Bouyer P, and Boron WF Proc Natl Acad Sci USA 102: 3875–3880, 2005). Here, we hypothesized that an early element in the CO2signal-transduction cascade might be either a receptor tyrosine kinase (RTK) or a receptor-associated (or soluble) tyrosine kinase (sTK). In our experiments, we found, first, that basolateral 17.5 μM genistein, a broad-spectrum tyrosine kinase inhibitor, virtually eliminates the CO2sensitivity of HCO3−absorption rate ( J[Formula: see text]). Second, we found that neither basolateral 250 nM nor basolateral 2 μM PP2, a high-affinity inhibitor for the Src family that also inhibits the Bcr-Abl sTK as well as the Kit RTK, reduces the CO2-stimulated increase in J[Formula: see text]. Third, we found that either basolateral 35 nM PD168393, a high-affinity inhibitor of RTKs in the erbB (i.e., EGF receptor) family, or basolateral 10 nM BPIQ-I, which blocks erbB RTKs by competing with ATP, eliminates the CO2sensitivity. In conclusion, the transduction of the CO2signal requires activation of a tyrosine kinase, perhaps an erbB. The possibilities include the following: 1) a TK is simply permissive for the effect of CO2on J[Formula: see text]; 2) a CO2receptor activates an sTK, which would then raise J[Formula: see text]; 3) a CO2receptor transactivates an RTK; and 4) the CO2receptor could itself be an RTK.
Proprioceptive Guidance of Saccades in Eye–Hand Coordination
Authors: Ren L. , Khan A. Z. , Blohm G. , Henriques D.Y.P. , Sergio L. E. , Crawford J. D.
Published: May 2006

The saccade generator updates memorized target representations for saccades during eye and head movements. Here, we tested if proprioceptive feedback from the arm can also update handheld object locations for saccades, and what intrinsic coordinate system(s) is used in this transformation. We measured radial saccades beginning from a central light-emitting diode to 16 target locations arranged peripherally in eight directions and two eccentricities on a horizontal plane in front of subjects. Target locations were either indicated 1) by a visual flash, 2) by the subject actively moving the handheld central target to a peripheral location, 3) by the experimenter passively moving the subject’s hand, or 4) through a combination of the above proprioceptive and visual stimuli. Saccade direction was relatively accurate, but subjects showed task-dependent systematic overshoots and variable errors in radial amplitude. Visually guided saccades showed the smallest overshoot, followed by saccades guided by both vision and proprioception, whereas proprioceptively guided saccades showed the largest overshoot. In most tasks, the overall distribution of saccade endpoints was shifted and expanded in a gaze- or head-centered cardinal coordinate system. However, the active proprioception task produced a tilted pattern of errors, apparently weighted toward a limb-centered coordinate system. This suggests the saccade generator receives an efference copy of the arm movement command but fails to compensate for the arm’s inertia-related directional anisotropy. Thus the saccade system is able to transform hand-centered somatosensory signals into oculomotor coordinates and combine somatosensory signals with visual inputs, but it seems to have a poorly calibrated internal model of limb properties.
Quantitative PCR-based approach for rapid phage display analysis: a foundation for high throughput vascular proteomic profiling
Authors: Ballard Victoria L. T. , Holm Jacquelyne M. , Edelberg Jay M.
Published: May 2006

Functional proteomic strategies offer unique advantages over current molecular array approaches, as the epitopes identified can directly provide bioactive peptides for investigational and/or translational applications. The vascular endothelium is well suited to proteomic assessment by in vivo phage display, but extensive enrichment and sequencing steps limit its application for high throughput molecular profiling. To overcome these limitations we developed a quantitative PCR (Q-PCR) strategy to allow the rapid quantification of in vivo phage binding. Primers were designed for distinct clones selected from a defined phage pool to probe for age-associated changes in cardiac vascular epitopes. Sensitivity and specificity of the primer sets were tested and confirmed in vitro. Q-PCR quantification of phage in vivo confirmed the preferential homing of all phage clones to the young rather than old cardiac vasculature and demonstrated a close correlation with phage measurements previously determined using traditional bacterial-based titration methods. This Q-PCR approach provides quantification of phage within hours of phage injection and may therefore be used for rapid, high throughput analysis of binding of defined phage sequences both in vivo and in vitro, complementing nonbiased phage approaches for the proteomic mapping of vascular beds and other tissues.
Proteomics and genomics of microgravity
Authors: Nichols Heather L. , Zhang Ning , Wen Xuejun
Published: May 2006

Many serious adverse physiological changes occur during spaceflight. In the search for underlying mechanisms and possible new countermeasures, many experimental tools and methods have been developed to study microgravity caused physiological changes, ranging from in vitro bioreactor studies to spaceflight investigations. Recently, genomic and proteomic approaches have gained a lot of attention; after major scientific breakthroughs in the fields of genomics and proteomics, they are now widely accepted and used to understand biological processes. Understanding gene and/or protein expression is the key to unfolding the mechanisms behind microgravity-induced problems and, ultimately, finding effective countermeasures to spaceflight-induced alterations. Significant progress has been made in identifying the genes/proteins responsible for these changes. Although many of these genes and/or proteins were observed to be either upregulated or downregulated, however, no large-scale genomics and proteomics studies have been published so far. This review aims at summarizing the current status of microgravity-related genomics and proteomics studies and stimulating large-scale proteomics and genomics research activities.
Hypoxia Increases Androgen Receptor Activity in Prostate Cancer Cells
Authors: Park Soo-Yeon , Kim Yun-Jeong , Gao Allen C. , Mohler James L. , Onate Sergio A. , Hidalgo Alejandro A. , Ip Clement , Park Eun-Mi , Yoon Sun Young , Park Young-Mee
Published: May 2006

Recent studies show that prostate cancer cells are able to survive in a hypoxic tumor environment, and the extent of tumor hypoxia correlates with poor clinical outcome. Androgen deprivation, the most common form of prostate cancer therapy, was itself shown to induce a state of transient hypoxia at the microenvironmental level. Because androgen receptor (AR) signaling plays a critical role in prostate cancer, we investigated the effect of hypoxia in regulating AR function. We found that in LNCaP prostate cancer cells, AR binding to the androgen-responsive element (ARE), prostate-specific antigen accumulation, and ARE-reporter gene activity were increased after hypoxia treatment. Hypoxia-enhanced AR function was also observed when AR was exogenously introduced into AR-null DU145 cells. Confocal microscopy and chromatin immunoprecipitation assays showed that AR translocation to the nucleus and AR recruitment to the prostate-specific antigen promoter were facilitated after hypoxia treatment. The AR stimulatory effect seemed to be ligand-dependent because it was abrogated when cells were cultured in an androgen-depleted medium, but was restored with the addition of R1881, a synthetic androgen. The sensitivity of AR activation to R1881 was also increased after hypoxia treatment. Although concentrations of <1 nmol/L R1881 did not induce ARE reporter activity under normoxic conditions, exposure to hypoxia greatly potentiated the AR response to low levels of R1881. Collectively, our results provide compelling evidence that changes in hypoxia/reoxygenation stimulate AR trans-activation and sensitization. The AR-stimulatory effect of an unstable tissue oxygenation milieu of a tumor is likely to contribute to treatment resistance and the emergence of recurrent prostate cancer. (Cancer Res 2006; 66(10): 5121-9)
Protein 4.1B/Differentially Expressed in Adenocarcinoma of the Lung-1 Functions as a Growth Suppressor in Meningioma Cells by Activating Rac1-Dependent c-Jun-NH2-kinase Signaling
Authors: Gerber Mark A. , Bahr Scott M. , Gutmann David H.
Published: May 2006

Meningiomas are the second most common brain tumor in adults, yet comparatively little is presently known about the dysregulated growth control pathways involved in their formation and progression. One of the most frequently observed genetic changes in benign meningioma involves loss of protein 4.1B expression. Previous studies from our laboratory have shown that protein 4.1B growth suppression in meningioma is associated with the activation of the c-Jun-NH2-kinase (JNK) pathway and requires localization of a small unique region (U2 domain) of protein 4.1B to the plasma membrane. To define the relationship between protein 4.1B expression and JNK activation, as well as to determine the mechanism of JNK activation by protein 4.1B, we used a combination of genetic and pharmacologic approaches. In this report, we show that protein 4.1B/differentially expressed in adenocarcinoma of the lung-1 (DAL-1) expression in meningioma cells in vitro results in JNK activation, which requires the sequential activation of Src, Rac1, and JNK. In addition, inhibition of Rac1 or JNK activation abrogates protein 4.1B/DAL-1 growth suppression and cyclin A regulation. Last, protein 4.1B/DAL-1 regulation of this critical growth control pathway in meningioma cells requires the presence of the U2 domain. Collectively, these observations provide the first mechanistic insights into the function of protein 4.1B as a growth regulator in meningioma cells. (Cancer Res 2006; 66(10): 5295-303)
Stromal Antiapoptotic Paracrine Loop in Perineural Invasion of Prostatic Carcinoma
Authors: Ayala Gustavo E. , Dai Hong , Tahir Salahaldin A. , Li Rile , Timme Terry , Ittmann Michael , Frolov Anna , Wheeler Thomas M. , Rowley David , Thompson Timothy C.
Published: May 2006

Caveolin-1 (cav-1) is a major scaffolding component of cell membrane invaginations (caveolae). It is involved in sequestering numerous effectors and signaling molecules and has antiapototic activities in prostate cancer. Perineural invasion (PNI) is associated with decreased apoptosis of cancer cells both in human tissues and the in vitro PNI model. We show here that stromal (perineurium) production of cav-1 is involved in a paracrine antiapoptotic loop in PNI. Transforming growth factor-β1 is up-regulated in the cancer cells as they approach the nerve and is thought to up-regulate cav-1 in the perineurium of nerves with prostate cancer. Cav-1 is then secreted into the microenvironment and used by prostate cancer cells to inhibit apoptosis. In the in vitro PNI model, this phenomenon is partially reversed by neutralizing cav-1 antibodies or using ganglia from cav-1 knockout mice. Our results show a novel paracrine mechanism used by the prostate cancer in PNI to increase their proliferative activity and decrease apoptosis. (Cancer Res 2006; 66(10): 5159-64)
Targeting Aurora Kinases for the Treatment of Prostate Cancer
Authors: Lee Edmund Chun Yu , Frolov Anna , Li Rile , Ayala Gustavo , Greenberg Norman M.
Published: May 2006

Inappropriate expression of the Aurora kinases can induce aberrant mitosis, centrosome irregularities, and chromosomal instability, which lead to anueploidy and cell transformation. Here, we report that Aurora-A and Aurora-B are highly expressed in primary human and mouse prostate cancers and prostate cancer cell lines. In clinical samples, levels of Aurora-A and Aurora-B were significantly elevated in prostatic intraepithelial neoplasia lesions and prostate tumors when compared with the non-neoplastic samples. Interestingly, expression of Aurora-A in non-neoplastic prostates correlated with seminal vesicle invasion (ρ = 0.275, P = 0.0169) and in prostate tumor with positive surgical margins (ρ = 0.265, P = 0.0161). In addition, nuclear expression of Aurora-B in prostatic intraepithelial neoplasia lesions correlated with clinical staging of the tumor (ρ = −0.4, P = 0.0474) whereas cytoplasmic expression in tumors correlated with seminal vesicle invasion (ρ = 0.282, P = 0.0098). Cell lines and primary tumors derived from the TRAMP model were also found to express high levels of Aurora-A and Aurora-B. When human PC3, LNCaP, and mouse C1A cells were treated with the potent Aurora kinase inhibitor VX680, which attenuates phosphorylation of histone H3, cancer cell survival was reduced. VX680 could further reduce cell viability >2-fold when used in combination with the chemotherapy drug doxorubicin. Our findings support a functional relationship between Aurora kinase expression and prostate cancer and the application of small-molecule inhibitors in therapeutic modalities. (Cancer Res 2006; 66(10): 4996-5002)
Epidermal Growth Factor Induces Insulin Receptor Substrate-2 in Breast Cancer Cells via c-Jun NH2-Terminal Kinase/Activator Protein-1 Signaling to Regulate Cell Migration
Authors: Cui Xiaojiang , Kim Hyun-Jung , Kuiatse Isere , Kim Heetae , Brown Powel H. , Lee Adrian V.
Published: May 2006

The epidermal growth factor (EGF) and insulin-like growth factor (IGF) signaling pathways are critically involved in cancer development and progression. However, how these two signals cross-talk with each other to regulate cancer cell growth is not clearly understood. In this study, we found that EGF remarkably induced expression of major IGF signaling components, insulin receptor substrate (IRS)-1 and IRS-2, an effect that could be blocked by EGF receptor (EGFR) tyrosine kinase inhibitors. Although both extracellular signal-regulated kinase and c-Jun NH2-terminal kinase (JNK) signaling pathways were involved in the EGF up-regulation of IRS-1, the IRS-2 induction by EGF was specifically mediated by JNK signaling. Consistent with this, EGF increased IRS-2 promoter activity, which was associated with recruitment of activator protein-1 (AP-1) transcription factors and was inhibited by blocking AP-1 activity. Moreover, EGF treatment enhanced IGF-I and integrin engagement-elicited tyrosine phosphorylation of IRS and their downstream signaling, such as binding to phosphatidylinositol 3′-kinase regulatory subunit p85. Finally, repressing the induction of IRS-2 levels abolished the EGF enhancement of cell motility, suggesting that increased IRS-2 is essential for the EGF regulation of breast cancer cell migration. Taken together, our results reveal a novel mechanism of cross-talk between the EGF and IGF signaling pathways, which could have implications in therapeutic applications of targeting EGFR in tumors. Because AP-1 activity is involved in breast cancer progression, our work may also suggest IRS-2 as a useful marker for aggressive breast cancer. (Cancer Res 2006; 66(10): 5304-13)
Membrane-Type 4 Matrix Metalloproteinase Promotes Breast Cancer Growth and Metastases
Authors: Chabottaux Vincent , Sounni Nor Eddine , Pennington Caroline J. , English William R. , van den Brûle Frédéric , Blacher Silvia , Gilles Christine , Munaut Carine , Maquoi Erik , Lopez-Otin Carlos , Murphy Gillian , Edwards Dylan R. , Foidart Jean-Michel , Noël Agnès
Published: May 2006

Membrane-type matrix metalloproteinases (MT-MMP) constitute a subfamily of six distinct membrane-associated MMPs. Although the contribution of MT1-MMP during different steps of cancer progression has been well documented, the significance of other MT-MMPs is rather unknown. We have investigated the involvement of MT4-MMP, a glycosylphosphatidylinositol–anchored protease, in breast cancer progression. Interestingly, immunohistochemical analysis shows that MT4-MMP production at protein level is strongly increased in epithelial cancer cells of human breast carcinomas compared with normal epithelial cells. Positive staining for MT4-MMP is also detected in lymph node metastases. In contrast, quantitative reverse transcription-PCR analysis reveals similar MT4-MMP mRNA levels in human breast adenocarcinomas and normal breast tissues. Stable transfection of MT4-MMP cDNA in human breast adenocarcinoma MDA-MB-231 cells does not affect in vitro cell proliferation or invasion but strongly promotes primary tumor growth and associated metastases in RAG-1 immunodeficient mice. We provide for the first time evidence that MT4-MMP overproduction accelerates in vivo tumor growth, induces enlargement of i.t. blood vessels, and is associated with increased lung metastases. These results identify MT4-MMP as a new putative target to design anticancer strategies. (Cancer Res 2006; 66(10): 5165-72)
Keratoepithelin Suppresses the Progression of Experimental Human Neuroblastomas
Authors: Becker Jürgen , Erdlenbruch Bernhard , Noskova Ievgeniia , Schramm Alexander , Aumailley Monique , Schorderet Daniel F. , Schweigerer Lothar
Published: May 2006

Neuroblastoma is the most common extracranial childhood tumor. High expression of activin A is associated with a favorable prognosis, but the contributing mechanisms have remained unclear. Our previous demonstration of the activin A–mediated up-regulation of keratoepithelin led to the consideration that keratoepithelin could modulate neuroblastoma growth and/or progression. We report here that enhanced keratoepithelin expression in human neuroblastoma cells suppresses neuroblastoma cell cohesion and adhesion to various extracellular matrix proteins and that it inhibits neuroblastoma cell proliferation and invasion in vitro and in vivo. Using microarray analysis, we identified several keratoepithelin-regulated genes that may contribute to these biological changes. Together with the observation that keratoepithelin is expressed in human neuroblastomas in vivo, our data suggest that keratoepithelin could play a beneficial role in neuroblastoma development and/or progression. (Cancer Res 2006; 66(10): 5314-21)
Resistance to Imatinib of Bcr/Abl P190 Lymphoblastic Leukemia Cells
Authors: Mishra Suparna , Zhang Bin , Cunnick Jess M. , Heisterkamp Nora , Groffen John
Published: May 2006

Around 20% of patients with acute lymphoblastic leukemia are Philadelphia chromosome positive (Ph-positive acute lymphoblastic leukemia) and express the Bcr/Abl tyrosine kinase. Treatment with the tyrosine kinase inhibitor Imatinib is currently standard for chronic myelogenous leukemia, which is also caused by Bcr/Abl. However, Imatinib has shown limited efficacy for treating Ph-positive acute lymphoblastic leukemia. In our study, we have investigated the effect of Imatinib therapy on murine P190 Bcr/Abl lymphoblastic leukemia cells. Three of four cultures were very sensitive to treatment with 5 μmol/L Imatinib. Significant cell death also initially occurred when the same cultures were treated in the presence of stromal support. However, after 6 days, remaining cells started to proliferate vigorously. The Bcr/Abl tyrosine kinase present in the cells that were now able to multiply in the presence of 5 μmol/L Imatinib was still inhibited by the drug. In concordance with this, the Abl ATP-binding pocket domain of Bcr/Abl in the resistant cells did not contain point mutations which would make the protein Imatinib resistant. The effect of stroma in selecting Imatinib-resistant lymphoblasts did not require direct cell-cell contact. SDF-1α could substitute for the presence of stromal cells. Our results show that stroma selects Imatinib-resistant Bcr/Abl P190 lymphoblasts that are less dependent on Bcr/Abl tyrosine kinase activity. Therefore, therapy for Ph-positive acute lymphoblastic leukemia, aimed at interfering with the protective effect of stroma in combination with Imatinib, could be of benefit for the eradication of the leukemic cells. (Cancer Res 2006; 66(10): 5387-93)
DNA Fusion Vaccines Induce Epitope-Specific Cytotoxic CD8+ T Cells against Human Leukemia-Associated Minor Histocompatibility Antigens
Authors: Rice Jason , Dunn Stuart , Piper Karen , Buchan Sarah L. , Moss Paul A. , Stevenson Freda K.
Published: May 2006

The graft-versus-leukemia effect of allogeneic stem-cell transplantation is believed to be mediated by T-cell recognition of minor histocompatibility antigens on recipient cells. For minor histocompatibility antigens HA-1 and HA-2, normal cell expression is restricted to hemopoietic cells, and boosting the immune response to these antigens may potentiate graft-versus-leukemia effect without accompanying graft-versus-host disease. To increase efficacy, expansion of HA-1- or HA-2-specific CTL before transplantation is desirable. However, primary HA-1- or HA-2-specific CTL expanded in vitro are often of low avidity. An alternative approach is to prime specific CTL responses in vivo by vaccination. Clearly, donor vaccination must be safe and specific. We have developed DNA fusion vaccines able to induce high levels of epitope-specific CTL using linked CD4+ T-cell help. The vaccines incorporate a domain of tetanus toxin (DOM) fused to a sequence encoding a candidate MHC class I binding peptide. This design generates antitumor CD8+ T-cell responses and protective immunity in preclinical models. For clinical application, we constructed vaccines encoding HLA-A*0201-restricted peptides from human HA-1 and HA-2, which were fused to DOM, and tested their performance in HLA-A*0201-transgenic mice. Priming induced epitope-specific, IFNγ-producing CD8+ T cells with cytotoxic function boosted to high levels with electroporation. Strikingly, these mouse T cells efficiently killed human lymphoblastoid cell lines expressing endogenous HA-1 or HA-2. High avidity is indicated by the independence of cytolysis from CD8/MHC class I interaction. These safe epitope-specific vaccines offer a potential strategy to prime HA-1- or HA-2-specific CTL in transplant donors before adoptive transfer. (Cancer Res 2006; 66(10): 5436-42)
BRCA1 Promotes Induction of ssDNA by Ionizing Radiation
Authors: Schlegel Brian P. , Jodelka Francine M. , Nunez Rafael
Published: May 2006

The BRCA1 tumor suppressor contributes to the repair of DNA double-strand breaks (DSB) through homologous recombination, but the mechanism is unknown. The rapid accumulation of BRCA1 into nuclear foci in response to induction of DNA breaks suggests that BRCA1 may function in an early step in the repair pathway. We examined the role of BRCA1 in one such early step, the resection of DSBs to generate ssDNA. The appearance of ssDNA in response to ionizing radiation is similar to that of BRCA1 foci formation, suggesting that the two processes are related. Furthermore, BRCA1 colocalizes to ssDNA sites induced by ionizing radiation. Overexpression of BRCA1 causes an increase in cells exhibiting ssDNA induced by ionizing radiation. Mutant BRCA1 that lacks the COOH-terminal BRCT domain also promotes ssDNA but fails to form nuclear foci. Knockdown of BRCA1 expression reduces ssDNA and Rad51 foci formation in response to ionizing radiation. These results indicate that BRCA1 promotes induction of ssDNA in response to ionizing radiation and accumulates at sites of ssDNA. (Cancer Res 2006; 66(10): 5181-9)
Identification of Candidate Alkylator-Induced Cancer Susceptibility Genes by Whole Genome Scanning in Mice
Authors: Fenske Timothy S. , McMahon Christine , Edwin Deepa , Jarvis Joseph C. , Cheverud James M. , Minn Matthew , Mathews Vikram , Bogue Molly A. , Province Michael A. , McLeod Howard L. , Graubert Timothy A.
Published: May 2006

Secondary malignancies are a serious adverse consequence of alkylator chemotherapy. The risk of developing an alkylator-associated malignancy is influenced by genetic background, although the relevant genetic factors are poorly understood. To screen for novel susceptibility factors, we established a mouse model of alkylator-induced malignancy. We exposed mice from 20 inbred strains to the prototypical alkylating agent, N-nitroso-N-ethylurea (ENU). ENU was a potent carcinogen in many of the strains tested, inducing 140 tumors in 240 ENU-treated mice (66% incidence of at least one tumor in evaluable mice), compared with a background incidence of 8% spontaneous tumors in 240 strain-, age-, and sex-matched control mice (relative risk, 8.4; P < 0.0001). A wide variety of tumor histologies were noted, including epithelial carcinomas, soft tissue sarcomas, and hematopoietic tumors. Cancer susceptibility was a heritable trait for the most common tumor types, lung adenocarcinoma (H2 = 0.25), T cell lymphoma (H2 = 0.19), and myeloid malignancies (H2 = 0.10). Quantitative trait locus mapping identified regions on chromosomes 3, 6, 9, and 15 containing candidate genes associated with lung adenoma, lung carcinoma, and lymphoma susceptibility. This novel mouse model recapitulates many features of human alkylator-associated cancer and supports the hypothesis that susceptibility to this syndrome is influenced by inherited polymorphisms that could be used to make informed clinical treatment decisions. (Cancer Res 2006; 66(10): 5029-38)
Intratumor CD4 T-Cell Accumulation Requires Stronger Priming than for Expansion and Lymphokine Secretion
Authors: Joncker Nathalie T. , Helft Julie , Jacquet Alexandra , Premel Virginie , Lantz Olivier
Published: May 2006

T cells need to migrate to and accumulate inside tumors before mediating rejection of the tumor. The number of specific T cells inside tumors may depend on the efficiency of priming in the draining lymph node (DLN), intratumor deletion, suppressive phenomena, or both. We used monoclonal anti-male antigen CD4 (Marilyn) T cells and tumor cell lines expressing or not the corresponding antigen (Dby) to analyze CD4 T-cell accumulation in tumors. Priming by MHC II+ or MHC II− male splenocytes or Dby+ tumor cells induced similar Marilyn T-cell expansion in the DLN and recirculation in other lymph nodes and capacity to produce IFN-γ. However, intratumor accumulation was different for each priming condition. In mice with Dby− tumors, MHC II+ male splenocyte priming induced greater, although not statistically significant, Marilyn T-cell accumulation in the tumors than MHC II− male splenocyte priming. In mice with Dby+ tumors, priming in the tumor DLN induced less Marilyn T-cell intratumor accumulation than priming by MHC II+ male splenocytes. We saw comparable differences for Marilyn T-cell accumulation in gut lamina propria, suggesting that priming affects effector T-cell accumulation in inflamed tissues. Mature dendritic cells were loaded with graded doses of Dby peptide to control for antigen-presenting cell characteristics during priming. We observed similar proliferation, with higher concentrations inducing higher intratumor accumulation. Thus, intratumor accumulation requires stronger stimulation than for proliferation or the capacity to secrete lymphokines. In this system, priming intensity alone can explain the number of intratumor T cells without having to call for intratumor deletion or suppression phenomena. (Cancer Res 2006; 66(10): 5443-51)
Lack of Rb and p53 Delays Cerebellar Development and Predisposes to Large Cell Anaplastic Medulloblastoma through Amplification of N-Myc and Ptch2
Authors: Shakhova Olga , Leung Carly , van Montfort Erwin , Berns Anton , Marino Silvia
Published: May 2006

Medulloblastomas are among the most common malignant brain tumors in childhood. They typically arise from neoplastic transformation of granule cell precursors in the cerebellum via deregulation of molecular pathways involved in normal cerebellar development. In a mouse model, we show here that impairment of the balance between proliferation and differentiation of granule cell precursors in the external granular layer of the developing cerebellum predisposes but is not sufficient to induce neoplastic transformation of these progenitor cells. Using array-based chromosomal comparative genomic hybridization, we show that genetic instability resulting from inactivation of the p53 pathway together with deregulation of proliferation induced by Rb loss eventually leads to neoplastic transformation of these cells by acquiring additional genetic mutations, mainly affecting N-Myc and Ptch2 genes. Moreover, we show that p53 loss influences molecular mechanisms that cannot be mimicked by the loss of either p19ARF, p21, or ATM. (Cancer Res 2006; 66(10): 5190-200)
Activator Protein-2 Overexpression Accounts for Increased Insulin Receptor Expression in Human Breast Cancer
Authors: Paonessa Francesco , Foti Daniela , Costa Vanessa , Chiefari Eusebio , Brunetti Giuseppe , Leone Francesco , Luciano Francesco , Wu Frank , Lee Amy S. , Gulletta Elio , Fusco Alfredo , Brunetti Antonio
Published: May 2006

Various studies have shown that the insulin receptor (IR) is increased in most human breast cancers, and both ligand-dependent malignant transformation and increased cell growth occur in cultured breast cells overexpressing the IR. However, although numerous in vivo and in vitro observations have indicated an important contributory role for the IR in breast cancer cell biology, the molecular mechanisms accounting for increased IR expression in breast tumors have not previously been elucidated. Herein, we did immunoblot analyses of nuclear protein from cultured breast cancer cells and normal and tumoral tissues from breast cancer patients combined with promoter studies by using a series of human wild-type and mutant IR promoter constructs. We provide evidence that IR overexpression in breast cancer is dependent on the assembly of a transcriptionally active multiprotein-DNA complex, which includes the high-mobility group A1 (HMGA1) protein, the developmentally regulated activator protein-2 (AP-2) transcription factor and the ubiquitously expressed transcription factor Sp1. In cultured breast cancer cells and human breast cancer specimens, the expression of AP-2 was significantly higher than that observed in cells and tissues derived from normal breast, and this overexpression paralleled the increase in IR expression. However, AP-2 DNA-binding activity was undetectable with the IR gene promoter, suggesting that transactivation of this gene by AP-2 might occur indirectly through physical and functional cooperation with HMGA1 and Sp1. Our findings support this hypothesis and suggest that in affected individuals, hyperactivation of the AP-2 gene through the overexpression of IR may play a key role in breast carcinogenesis. (Cancer Res 2006; 66(10): 5085-93)
PTEN/Akt Signaling through Epidermal Growth Factor Receptor Is Prerequisite for Angiogenesis by Hepatocellular Carcinoma Cells That Is Susceptible to Inhibition by Gefitinib
Authors: Ueda Shu-ichi , Basaki Yuji , Yoshie Masumi , Ogawa Katsuhiro , Sakisaka Shotaro , Kuwano Michihiko , Ono Mayumi
Published: May 2006

Hepatocellular carcinoma (HCC) is one of the most common tumor-related causes of death worldwide for which there is still no satisfactory treatment. We previously reported the antiangiogenic effect of gefitinib, a selective epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor that has been used successfully to treat lung cancer. In this study, we investigated the effects of gefitinib on tumor-induced angiogenesis by using HCC cell lines (HCC3, CBO12C3, and AD3) in vitro as well as in vivo. Oral administration of gefitinib inhibited angiogenesis induced by HCC3 and CBO12C3, but not by AD3 in the mouse dorsal air sac model. Production of both vascular endothelial growth factor (VEGF) and chemokine C-X-C motif ligand 1 (CXCL1) by EGF-stimulated HCC was more markedly inhibited by gefitinib in HCC3 and CBO12C3 cells than in AD3 cells. EGF stimulated the phosphorylation of EGFR, Akt, and extracellular signal-regulated kinase 1/2 (ERK1/2) in HCC3 and CBO12C3 cells, whereas EGF stimulated phosphorylation of EGFR and ERK1/2, but not Akt in AD3 cells. In fact, Akt was constitutively activated in the absence of EGF in AD3 cells. Gefitinib inhibited Akt phosphorylation in all three cell lines, but it was about five times less effective in AD3 cells. The concentration of PTEN in AD3 cells was about a half that in HCC3 and CBO12C3 cells. Transfection of HCC3 cells with PTEN small interfering RNA reduced their sensitivity to gefitinib in terms of its inhibitory effect on both Akt phosphorylation and the production of VEGF and CXCL1. In conclusion, effect of gefitinib on HCC-induced angiogenesis depends on its inhibition of the production of angiogenic factors, probably involving a PTEN/Akt signaling pathway. (Cancer Res 2006; 66(10): 5346-53)
Differentially Active Origins of DNA Replication in Tumor versus Normal Cells
Authors: Di Paola Domenic , Price Gerald B. , Zannis-Hadjopoulos Maria
Published: May 2006

Previously, a degenerate 36 bp human consensus sequence was identified as a determinant of autonomous replication in eukaryotic cells. Random mutagenesis analyses further identified an internal 20 bp of the 36 bp consensus sequence as sufficient for acting as a core origin element. Here, we have located six versions of the 20 bp consensus sequence (20mer) on human chromosome 19q13 over a region spanning ∼211 kb and tested them for ectopic and in situ replication activity by transient episomal replication assays and nascent DNA strand abundance analyses, respectively. The six versions of the 20mer alone were capable of supporting autonomous replication of their respective plasmids, unlike random genomic sequence of the same length. Furthermore, comparative analyses of the endogenous replication activity of these 20mers at their respective chromosomal sites, in five tumor/transformed and two normal cell lines, done by in situ chromosomal DNA replication assays, involving preparation of nascent DNA by the λ exonuclease method and quantification by real-time PCR, showed that these sites coincided with chromosomal origins of DNA replication in all cell lines. Moreover, a 2- to 3-fold higher origin activity in the tumor/transformed cells by comparison to the normal cells was observed, suggesting a higher activation of these origins in tumor/transformed cell lines. (Cancer Res 2006; 66(10): 5094-103)
Doxorubicin plus Interleukin-2 Chemoimmunotherapy against Breast Cancer in Mice
Authors: Ewens Andrew , Luo Liqun , Berleth Erica , Alderfer James , Wollman Robert , Hafeez Bilal Bin , Kanter Peter , Mihich Enrico , Ehrke M. Jane
Published: May 2006

As recently characterized, following s.c. implantation into syngeneic C57BL/6 mice, E0771 tumor invades locally into dermal layers and peritoneum, metastasizes to the lung, and induces a nonspecific immunosuppression in the host. Using this breast medullar adenocarcinoma model, a therapy consisting of a single moderate dose of doxorubicin followed by twice daily moderate doses of interleukin-2 for 30 days was examined for efficacy and mechanism of action when given to animals with established disease. This combination treatment, but not combinants alone, resulted in tumor-free long-term survival of 40% of the mice without significant toxicity and 83% of survivors had immune memory specific for E0771 cells. Treatment also decreased immune suppression induced by E0771 tumor. Full response to treatment required functional CD8+ T cells, whereas depletion of natural killer cells caused only a reduction in response rate. A serum “biomarker” profile that correlated with, and seemed predictive of, response to treatment was identified by nuclear magnetic resonance–based metabonomic analysis. The efficacy of this nontoxic treatment and the potential to be able to predict which individual is responding to treatment are characteristics that make this chemoimmunotherapy attractive for clinical testing. (Cancer Res 2006; 66(10): 5419-26)
Vaccination with Human HER-2/neu(435-443) CTL Peptide Induces Effective Antitumor Immunity against HER-2/neu-Expressing Tumor CellsIn vivo
Authors: Gritzapis Angelos D. , Mahaira Louisa G. , Perez Sonia A. , Cacoullos Nike T. , Papamichail Michael , Baxevanis Constantin N.
Published: May 2006

HER-2/neu is a self-antigen expressed by tumors and nonmalignant epithelial tissues. The possibility of self-tolerance to HER-2/neu-derived epitopes has raised questions concerning their utility in antitumor immunotherapy. Altered HER-2/neu peptide ligands capable of eliciting enhanced immunity to tumor-associated HER-2/neu epitopes may circumvent this problem. The human CTL peptide HER-2/neu (435-443) [hHER-2(9435)] represents a xenogeneic altered peptide ligand of its mouse homologue, differing by one amino acid residue at position 4. In contrast to mHER-2(9435), vaccination of HLA-A*0201 transgenic (HHD) mice with hHER-2(9435) significantly increased the frequency of mHER-2(9435)-specific CTL and also induced strong protective and therapeutic immunity against the transplantable ALC tumor cell line transfected to coexpress HLA-A*0201 and hHER-2/neu or rHER-2/neu. Similar results were also obtained with wild-type C57BL/6 mice inoculated with HER-2/neu transfectants of ALC. Adoptive transfer of CD8+ CTL from mice immunized with hHER-2(9435) efficiently protected naive syngeneic mice inoculated with ALC tumors. In conclusion, our results show that HER-2(9435) serves as a tumor rejection molecule. They also propose a novel approach for generating enhanced immunity against a self-HER-2/neu CTL epitope by vaccinating with xenogeneic altered peptide ligands and provide useful insights for the design of improved peptide-based vaccines for the treatment of patients with HER-2/neu-overexpressing tumors. (Cancer Res 2006; 66(10): 5452-60)
Role of Macrophage Inhibitory Cytokine-1 in Tumorigenesis and Diagnosis of Cancer
Authors: Bauskin Asne R. , Brown David A. , Kuffner Tamara , Johnen Heiko , Luo X. Wei , Hunter Mark , Breit Samuel N.
Published: May 2006

Macrophage inhibitory cytokine-1 (MIC-1), a transforming growth factor-β superfamily cytokine, is involved in tumor pathogenesis, and its measurement can be used as a clinical tool for the diagnosis and management of a wide range of cancers. Although generally considered to be part of the cell's antitumorigenic repertoire, MIC-1 secretion, processing, and latent storage suggest a complex, dynamic variability in MIC-1 bioavailability in the tumor microenvironment, potentially modulating tumor progression and invasiveness. (Cancer Res 2006; 66(10): 4983-5)
HER-2/neu Status Is a Determinant of Mammary Aromatase Activity In vivo: Evidence for a Cyclooxygenase-2-Dependent Mechanism
Authors: Subbaramaiah Kotha , Howe Louise R. , Port Elisa R. , Brogi Edi , Fishman Jack , Liu Catherine H. , Hla Timothy , Hudis Clifford , Dannenberg Andrew J.
Published: May 2006

Cytochrome P450 aromatase (aromatase), a product of the CYP19 gene, catalyzes the synthesis of estrogens from androgens. Given the significance of estrogen synthesis in hormone-dependent breast carcinogenesis, it is important to elucidate the mechanisms that regulate CYP19 expression. The main objective of this study was to define the interrelationship between HER-2/neu, cyclooxygenase-2 (COX-2), and aromatase in mammary tissue. Mammary aromatase activity and prostaglandin E2 (PGE2) levels were increased in mice with mammary-targeted expression of a COX-2 transgene. In vitro, overexpressing COX-2 caused both increased PGE2 production and aromatase activity, effects that were suppressed by celecoxib, a selective COX-2 inhibitor. Previously, we found that overexpression of HER-2/neu was associated with increased levels of COX-2 in human breast cancers. Here, we show that overexpression of HER-2/neu is also associated with increased aromatase activity. These results suggested the possibility that COX-2 was the functional intermediate linking HER-2/neu and aromatase. Consistent with this idea, COX-2 deficiency led to a gene dose-dependent reduction in mammary aromatase activity in a HER-2/neu transgenic mouse model. Complementary in vitro studies showed that HER-2/neu–mediated induction of PGE2 synthesis and aromatase activity were suppressed by inhibiting COX-2. Collectively, our data indicate that COX-2 is the functional intermediate linking HER-2/neu and aromatase and suggest that inhibitors of PGE2 synthesis will suppress estrogen biosynthesis in breast tissue. (Cancer Res 2006; 66(10): 5504-11)
KRASD13 Promotes Apoptosis of Human Colorectal Tumor Cells by ReovirusT3D and Oxaliplatin but not by Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand
Authors: Smakman Niels , van den Wollenberg Diana J.M. , Elias Sjoerd G. , Sasazuki Takehiko , Shirasawa Senji , Hoeben Rob C. , Borel Rinkes Inne H.M. , Kranenburg Onno
Published: May 2006

Colorectal tumors frequently contain activating mutations in KRAS. ReovirusT3D is an oncolytic virus that preferentially kills tumor cells with an activated Ras pathway. Here we have assessed the contribution of endogenous mutant KRAS in human colorectal cancer cell lines to ReovirusT3D replication and to tumor cell oncolysis. In addition, treatment combinations involving ReovirusT3D, oxaliplatin, and tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) were tested for their efficacy in tumor cell killing. The mutation status of KRAS did not predict the sensitivity of a panel of human colorectal cancer cell lines to ReovirusT3D. Virus replication was observed in all cell lines tested regardless of KRAS status and was not affected by deletion of endogenous mutant KRASD13. However, deletion of KRASD13 or p53 did reduce apoptosis induction by ReovirusT3D whereas deletion of β-cateninΔS45 had no effect. Likewise, KRASD13- or p53-deficient cells display reduced sensitivity to oxaliplatin but not to death receptor activation by TRAIL. Finally, the treatment of colorectal cancer cells with ReovirusT3D combined with either oxaliplatin or TRAIL resulted in a nonsynergistic increase in tumor cell killing. We conclude that oncolysis of human tumor cells by ReovirusT3D is not determined by the extent of virus replication but by their sensitivity to apoptosis induction. Oncogenic KRASD13 increases tumor cell sensitivity to activation of the cell-intrinsic apoptosis pathway without affecting ReovirusT3D replication. (Cancer Res 2006; 66(10): 5403-8)
Malignant Transformation of Immortalized HaCaT Keratinocytes through Deregulated Nuclear Factor κB Signaling
Authors: Ren Qing , Kari Csaba , Quadros Marlene R.D. , Burd Randy , McCue Peter , Dicker Adam P. , Rodeck Ulrich
Published: May 2006

Previous studies addressing functional aspects of nuclear factor κB (NF-κB) activation in normal and transformed keratinocytes revealed complex and seemingly contradictory roles of this transcription factor in this cell type. In normal skin, NF-κB signaling seems to inhibit squamous cell carcinoma development whereas, in squamous cell carcinoma themselves, deregulated NF-κB expression and/or signaling is frequently observed. To further investigate this paradox, we focused on NF-κB activation as it relates to the transformed phenotype of immortalized but nontumorigenic human keratinocytes (HaCaT cells). We observed that NF-κB activity contributed to survival and growth of cultured HaCaT keratinocytes as shown by use of pharmacologic NF-κB inhibitors, RNA interference, and inducible overexpression of a dominant interfering IκB construct. NF-κB activation was largely provided through interaction with extracellular matrix components because preventing cell attachment by forced suspension culture markedly reduced NFκB signaling associated with cell death (anoikis); conversely, anoikis was partially reversed by NF-κB activation induced either by tumor necrosis factor-α treatment or by overexpressing the NF-κB p65 subunit in HaCaT cells. Furthermore, overexpression of NF-κBp65 in HaCaT cells induced colony formation in soft agar and tumorigenicity in nude mice. In summary, as opposed to normal keratinocytes, immortalized HaCaT keratinocytes provide a cellular context in which deregulated NF-κB signaling supports multiple malignant traits in vitro and in vivo. (Cancer Res 2006; 66(10): 5209-15)
BRCC36 Is Essential for Ionizing Radiation–Induced BRCA1 Phosphorylation and Nuclear Foci Formation
Authors: Chen Xiaowei , Arciero Cletus A. , Wang Chunrong , Broccoli Dominique , Godwin Andrew K.
Published: May 2006

We have previously reported the identification and characterization of a novel BRCA1/2 interacting protein complex, BRCC (BRCA1/2-containing complex). BRCC36, one of the proteins in BRCC, directly interacts with BRCA1, and regulates the ubiquitin E3 ligase activity of BRCC. Importantly, BRCC36 is aberrantly expressed in the vast majority of breast tumors, indicating a potential role in the pathogenesis of this disease. To further elucidate the functional consequence of abnormal BRCC36 expression in breast cancer, we have done in vivo silencing studies using small interfering RNAs targeting BRCC36 in breast cancer cell lines, i.e., MCF-7, ZR-75-1, and T47D. Knock-down of BRCC36 alone does not affect cell growth, but when combined with ionizing radiation (IR) exposure, it leads to an increase in the percentage of cells undergoing apoptosis when compared with the small interfering RNA control group in breast cancer cells. Immunoblot analysis shows that inhibition of BRCC36 has no effect on the activation of ATM, expression of p21 and p53, or BRCA1-BARD1 interaction following IR exposure. Importantly, BRCC36 depletion disrupts IR-induced phosphorylation of BRCA1. Immunofluorescent staining of BRCA1 and γ-H2AX indicates that BRCC36 depletion prevents the formation of BRCA1 nuclear foci in response to DNA damage in breast cancer cells. These results show that down-regulation of BRCC36 expression impairs the DNA repair pathway activated in response to IR by inhibiting BRCA1 activation, thereby sensitizing breast cancer cells to IR-induced apoptosis. (Cancer Res 2006; 66(10): 5039-46)