bluuebunny/crossref_metadata_2025 huggingface dataset:
Containment of Tumor-Colonizing Bacteria by Host Neutrophils
Authors: Westphal Kathrin , Leschner Sara , Jablonska Jadwiga , Loessner Holger , Weiss Siegfried
Published: April 2008

Administration of facultative anaerobic bacteria like Salmonella typhimurium, Shigella flexneri, and Escherichia coli to tumor-bearing mice leads to a preferential accumulation and proliferation of the microorganisms within the solid tumor. Until now, all known tumor-targeting bacteria have shown poor dissemination inside the tumors. They accumulate almost exclusively in large necrotic areas and spare a rim of viable tumor cells. Interestingly, the bacteria-containing necrotic region is separated from viable tumor cells by a barrier of host neutrophils that have immigrated into the tumor. We here report that depletion of host neutrophils results in a noticeably higher total number of bacteria in the tumor and that bacteria were now also able to migrate into vital tumor tissue. Most remarkably, an increase in the size of the necrosis was observed, and complete eradication of established tumors could be observed under these conditions. Thus, bacteria-mediated tumor therapy can be amplified by depletion of host neutrophils. [Cancer Res 2008;68(8):2952–60]
Triterpenoid CDDO-Methyl Ester Inhibits the Janus-Activated Kinase-1 (JAK1)→Signal Transducer and Activator of Transcription-3 (STAT3) Pathway by Direct Inhibition of JAK1 and STAT3
Authors: Ahmad Rehan , Raina Deepak , Meyer Colin , Kufe Donald
Published: April 2008

The C-28 methyl ester of the oleane triterpenoid 2-cyano-3,12-dioxooleana-1,9-dien-28-oic acid (CDDO-Me) induces apoptosis of human cancer cells by disrupting redox balance and is in clinical trials. CDDO-Me contains α,β-unsaturated carbonyl groups that form reversible adducts with thiol nucleophiles. The present studies show that CDDO-Me blocks interleukin-6 (IL-6)–induced and constitutive activation of the Janus-activated kinase 1 (JAK1) in cells. In support of a direct mechanism, CDDO-Me forms adducts with JAK1 at Cys1077 in the kinase domain and inhibits JAK1 activity. In concert with these results, CDDO-Me blocked IL-6–induced and constitutive activation of signal transducer and activator of transcription 3 (STAT3). Moreover, we show that CDDO-Me (a) binds directly to STAT3 by a mechanism dependent on the alkylation of Cys259 and (b) inhibits the formation of STAT3 dimers. These findings indicate that CDDO-Me inhibits activation of the JAK1→STAT3 pathway by forming adducts with both JAK1 and STAT3. [Cancer Res 2008;68(8):2920–6]
p53 Loss Synergizes with Estrogen and Papillomaviral Oncogenes to Induce Cervical and Breast Cancers
Authors: Shai Anny , Pitot Henry C. , Lambert Paul F.
Published: April 2008

Whereas the tumor suppressor p53 gene is frequently mutated in most human cancers, this is not the case in human papillomavirus (HPV)-associated cancers, presumably because the viral E6 oncoprotein inactivates the p53 protein. The ability of E6 to transform cells in tissue culture and induce cancers in mice correlates in part with its ability to inactivate p53. In this study, we compared the expression of the HPV16 E6 oncogene to the conditional genetic disruption of p53 in the context of a mouse model for cervical cancer in which estrogen is a critical cofactor. Nearly all of the K14Crep53f/f mice treated with estrogen developed cervical cancer, a stark contrast to its complete absence in like-treated K14E6WTp53f/f mice, indicating that HPV16 E6 must only partially inactivate p53. p53-independent activities of E6 also contributed to carcinogenesis, but in the female reproductive tract, these activities were manifested only in the presence of the HPV16 E7 oncogene. Interestingly, treatment of K14Crep53f/f mice with estrogen also resulted in mammary tumors after only a short latency, many of which were positive for estrogen receptor α. The majority of these mammary tumors were of mixed cell types, suggestive of their originating from a multipotent progenitor. Furthermore, a subset of mammary tumors arising in the estrogen-treated, p53-deficient mammary glands exhibited evidence of an epithelial to mesenchymal transition. These data show the importance of the synergy between estrogen and p53 insufficiency in determining basic properties of carcinogenesis in hormone-responsive tissues, such as the breast and the reproductive tract. [Cancer Res 2008;68(8):2622–31]
Bile Acid Exposure Up-regulates Tuberous Sclerosis Complex 1/Mammalian Target of Rapamycin Pathway in Barrett's-Associated Esophageal Adenocarcinoma
Authors: Yen Chia-Jui , Izzo Julie G. , Lee Dung-Fang , Guha Sushovan , Wei Yongkun , Wu Tsung-Teh , Chen Chun-Te , Kuo Hsu-Ping , Hsu Jung-Mao , Sun Hui-Lung , Chou Chao-Kai , Buttar Navtej S. , Wang Kenneth K. , Huang Peng , Ajani Jaffer , Hung Mien-Chie
Published: April 2008

Barrett's esophagus, a columnar metaplasia of the lower esophagus epithelium related to gastroesophageal reflux disease, is the strongest known risk factor for the development of esophageal adenocarcinoma (EAC). Understanding the signal transduction events involved in esophageal epithelium carcinogenesis may provide insights into the origins of EAC and may suggest new therapies. To elucidate the molecular pathways of bile acid–induced tumorigenesis, the newly identified inflammation-associated signaling pathway involving IκB kinases β (IKKβ), tuberous sclerosis complex 1 (TSC1), and mammalian target of rapamycin (mTOR) downstream effector S6 kinase (S6K1) was confirmed to be activated in immortalized Barrett's CPC-A and CPC-C cells and esophageal cancer SEG-1 and BE3 cells. Phosphorylation of TSC1 and S6K1 was induced in response to bile acid stimulation. Treatment of these cells with the mTOR inhibitor rapamycin or the IKKβ inhibitor Bay 11-7082 suppressed bile acid–induced cell proliferation and anchorage-independent growth. We next used an orthotopic rat model to evaluate the role of bile acid in the progression of Barrett's esophagus to EAC. Of interest, we found high expression of phosphorylated IKKβ (pIKKβ) and phosphorylated S6K1 (pS6K1) in tumor tissues and the Barrett's epithelium compared with normal epithelium. Furthermore, immunostaining of clinical EAC tissue specimens revealed that pIKKβ expression was strongly correlated with pS6K1 level. Together, these results show that bile acid can deregulate TSC1/mTOR through IKKβ signaling, which may play a critical role in EAC progression. In addition, Bay 11-7082 and rapamycin may potentially be chemopreventive drugs against Barrett's esophagus–associated EAC. [Cancer Res 2008;68(8):2632–40]
Double-Strand Break Damage and Associated DNA Repair Genes Predispose Smokers to Gene Methylation
Authors: Leng Shuguang , Stidley Christine A. , Willink Randy , Bernauer Amanda , Do Kieu , Picchi Maria A. , Sheng Xin , Frasco Melissa A. , Van Den Berg David , Gilliland Frank D. , Zima Christopher , Crowell Richard E. , Belinsky Steven A.
Published: April 2008

Gene promoter hypermethylation in sputum is a promising biomarker for predicting lung cancer. Identifying factors that predispose smokers to methylation of multiple gene promoters in the lung could affect strategies for early detection and chemoprevention. This study evaluated the hypothesis that double-strand break (DSB) repair capacity and sequence variation in genes in this pathway are associated with a high methylation index in a cohort of current and former cancer-free smokers. A 50% reduction in the mean level of DSB repair capacity was seen in lymphocytes from smokers with a high methylation index, defined as three or more of eight genes methylated in sputum, compared with smokers with no genes methylated. The classification accuracy for predicting risk for methylation was 88%. Single nucleotide polymorphisms within the MRE11A, CHEK2, XRCC3, DNA-PKc, and NBN DNA repair genes were highly associated with the methylation index. A 14.5-fold increased odds for high methylation was seen for persons with seven or more risk alleles of these genes. Promoter activity of the MRE11A gene that plays a critical role in recognition of DNA damage and activation of ataxia-telangiectasia mutated was reduced in persons with the risk allele. Collectively, ours is the first population-based study to identify DSB DNA repair capacity and specific genes within this pathway as critical determinants for gene methylation in sputum, which is, in turn, associated with elevated risk for lung cancer. [Cancer Res 2008;68(8):3049–56]
Distinct RAD51 Associations with RAD52 and BCCIP in Response to DNA Damage and Replication Stress
Authors: Wray Justin , Liu Jingmei , Nickoloff Jac A. , Shen Zhiyuan
Published: April 2008

RAD51 has critical roles in homologous recombination (HR) repair of DNA double-strand breaks (DSB) and restarting stalled or collapsed replication forks. In yeast, Rad51 function is facilitated by Rad52 and other “mediators.” Mammalian cells express RAD52, but BRCA2 may have supplanted RAD52 in mediating RAD51 loading onto ssDNA. BCCIP interacts with BRCA2, and both proteins are important for RAD51 focus formation after ionizing radiation and HR repair of DSBs. Nonetheless, mammalian RAD52 shares biochemical activities with yeast Rad52, including RAD51 binding and single-strand annealing, suggesting a conserved role in HR. Because RAD52 and RAD51 associate, and RAD51 and BCCIP associate, we investigated the colocalization of RAD51 with BCCIP and RAD52 in human cells. We found that RAD51 colocalizes with BCCIP early after ionizing radiation, with RAD52 later, and there was little colocalization of BCCIP and RAD52. RAD52 foci are induced to a greater extent by hydroxyurea, which stalls replication forks, than by ionizing radiation. Using fluorescence recovery after photo bleaching, we show that RAD52 mobility is reduced to a greater extent by hydroxyurea than ionizing radiation. However, BCCIP showed no changes in mobility after hydroxyurea or ionizing radiation. We propose that BCCIP-dependent repair of DSBs by HR is an early RAD51 response to ionizing radiation–induced DNA damage, and that RAD52-dependent HR occurs later to restart a subset of blocked or collapsed replication forks. RAD52 and BRCA2 seem to act in parallel pathways, suggesting that targeting RAD52 in BRCA2-deficient tumors may be effective in treating these tumors. [Cancer Res 2008;68(8):2699–706]
MicroRNAs 221 and 222 Bypass Quiescence and Compromise Cell Survival
Authors: Medina Ricardo , Zaidi Sayyed K. , Liu Chang-Gong , Stein Janet L. , vanWijnen Andre J. , Croce Carlo M. , Stein Gary S.
Published: April 2008

MicroRNAs (miRNA) have tumor suppressive and oncogenic potential in human cancer, but whether and how miRNAs control cell cycle progression is not understood. To address this question, we carried out a comprehensive analysis of miRNA expression during serum stimulation of quiescent human cells. Time course analyses revealed that four miRNAs are up-regulated and >100 miRNAs are down-regulated, as cells progress beyond the G1-S phase transition. We analyzed the function of two up-regulated miRNAs (miR-221 and miR-222) that are both predicted to target the cell growth suppressive cyclin-dependent kinase inhibitors p27 and p57. Our results show that miR-221 and miR-222 both directly target the 3′ untranslated regions of p27 and p57 mRNAs to reduce reporter gene expression, as well as diminish p27 and p57 protein levels. Functional studies show that miR-221 and miR-222 prevent quiescence when elevated during growth factor deprivation and induce precocious S-phase entry, thereby triggering cell death. Thus, the physiologic up-regulation of miR-221 and miR-222 is tightly linked to a cell cycle checkpoint that ensures cell survival by coordinating competency for initiation of S phase with growth factor signaling pathways that stimulate cell proliferation. [Cancer Res 2008;68(8):2773–80]
BCR/ABL Inhibits Mismatch Repair to Protect from Apoptosis and Induce Point Mutations
Authors: Stoklosa Tomasz , Poplawski Tomasz , Koptyra Mateusz , Nieborowska-Skorska Margaret , Basak Grzegorz , Slupianek Artur , Rayevskaya Marina , Seferynska Ilona , Herrera Larry , Blasiak Janusz , Skorski Tomasz
Published: April 2008

BCR/ABL kinase–positive chronic myelogenous leukemia (CML) cells display genomic instability leading to point mutations in various genes including bcr/abl and p53, eventually causing resistance to imatinib and malignant progression of the disease. Mismatch repair (MMR) is responsible for detecting misincorporated nucleotides, resulting in excision repair before point mutations occur and/or induction of apoptosis to avoid propagation of cells carrying excessive DNA lesions. To assess MMR activity in CML, we used an in vivo assay using the plasmid substrate containing enhanced green fluorescent protein (EGFP) gene corrupted by T:G mismatch in the start codon; therefore, MMR restores EGFP expression. The efficacy of MMR was reduced ∼2-fold in BCR/ABL-positive cell lines and CD34+ CML cells compared with normal counterparts. MMR was also challenged by N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), which generates O6-methylguanine and O4-methylthymine recognized by MMR system. Impaired MMR activity in leukemia cells was associated with better survival, accumulation of p53 but not of p73, and lack of activation of caspase 3 after MNNG treatment. In contrast, parental cells displayed accumulation of p53, p73, and activation of caspase 3, resulting in cell death. Ouabain-resistance test detecting mutations in the Na+/K+ ATPase was used to investigate the effect of BCR/ABL kinase–mediated inhibition of MMR on mutagenesis. BCR/ABL-positive cells surviving the treatment with MNNG displayed ∼15-fold higher mutation frequency than parental counterparts and predominantly G:C→A:T and A:T→G:C mutator phenotype typical for MNNG-induced unrepaired lesions. In conclusion, these results suggest that BCR/ABL kinase abrogates MMR activity to inhibit apoptosis and induce mutator phenotype. [Cancer Res 2008;68(8):2576–80]
Urinary Biomarkers Predict Brain Tumor Presence and Response to Therapy
Authors: Smith Edward R. , Zurakowski David , Saad Ali , Scott R. Michael , Moses Marsha A.
Published: April 2008

Purpose: A major difficulty in treating brain tumors is the lack of effective methods of identifying novel or recurrent disease. In this study, we have evaluated the efficacy of urinary matrix metalloproteinases (MMP) as diagnostic biomarkers for brain tumors.

Experimental Design: Urine, cerebrospinal fluid, and tissue specimens were collected from patients with brain tumors. Zymography, ELISA, and immunohistochemistry were used to characterize the presence of MMP-2, MMP-9, MMP-9/neutrophil gelatinase–associated lipocalin (NGAL), and vascular endothelial growth factor (VEGF). Results were compared between age- and sex-matched controls and subjected to univariate and multivariate statistical analyses.

Results: Evaluation of a specific panel of urinary biomarkers by ELISA showed significant elevations of MMP-2, MMP-9, MMP-9/NGAL, and VEGF (all P < 0.001) in samples from brain tumor patients compared with controls. Multiplexing MMP-2 and VEGF provided superior accuracy compared with any other combination or individual biomarker. Receiver-operating characteristics curves for MMP-2 and VEGF showed excellent discrimination. Immunohistochemistry identified these same proteins in the source tumor tissue. A subset of patients with longitudinal follow-up revealed subsequent clearing of biomarkers after tumor resection.

Conclusion: We report, for the first time, the identification of a panel of urinary biomarkers that predicts the presence of brain tumors. These biomarkers correlate with presence of disease, decrease with treatment, and can be tracked from source tissue to urine. These data support the hypothesis that urinary MMPs and associated proteins are useful predictors of the presence of brain tumors and may provide a basis for a novel, noninvasive method to identify new brain tumors and monitor known tumors after treatment.
Clinical, Radiographic, and Biochemical Characterization of Multiple Myeloma Patients with Osteonecrosis of the Jaw
Authors: Raje Noopur , Woo Sook-Bin , Hande Karen , Yap Jeffrey T. , Richardson Paul G. , Vallet Sonia , Treister Nathaniel , Hideshima Teru , Sheehy Niall , Chhetri Shweta , Connell Brendan , Xie Wanling , Tai Yu-Tzu , Szot-Barnes Agnieszka , Tian Mei , Schlossman Robert L. , Weller Edie , Munshi Nikhil C. , Van Den Abbeele Annick D. , Anderson Kenneth C.
Published: April 2008

Purpose: Osteonecrosis of the jaw (ONJ) has been reported in patients with a history of aminobisphosphonate use. This study was conducted in order to define ONJ clinically and radiographically and gain insights into its pathophysiology.

Experimental Design: Eleven multiple myeloma (MM) patients with ONJ were included in the study. Patients underwent clinical, biochemical, radiographic, and molecular profiling. Ten MM patients on aminobisphosphonates without ONJ and five healthy volunteers were used as controls for biochemical and molecular studies.

Results: MM patients with ONJ were treated with either pamidronate (n = 3), zoledronate (n = 4), or both agents sequentially (n = 4) for a mean of 38.7 months. Radiographic studies showed bone sclerosis and fragmentation on plain films and computerized tomography. Quantitative regional analysis of NaF-PET and FDG-PET scans confirmed an increased standardized uptake value (SUVmax) in areas of ONJ. The target to background ratio of SUVmax was significantly greater for NaF-PET compared with FDG-PET scan. Biochemical bone marker data and transcriptional profiling studies showed that genes and proteins involved in osteoblast and osteoclast signaling cascades were significantly down-regulated in patients with ONJ.

Conclusions: ONJ was associated with a mean duration of 38.7 months of aminobisphosphonate exposure. Radiographic and functional imaging confirmed sites of clinically established ONJ. Gene and protein studies are consistent with altered bone remodeling, evidenced by suppression of both bone resorption and formation.
Dopamine Increases the Efficacy of Anticancer Drugs in Breast and Colon Cancer Preclinical Models
Authors: Sarkar Chandrani , Chakroborty Debanjan , Chowdhury Uttio Roy , Dasgupta Partha Sarathi , Basu Sujit
Published: April 2008

Purpose: Because neurotransmitter dopamine inhibits vascular permeability factor/vascular endothelial growth factor (VEGF)–induced angiogenesis and as anti-VEGF agents act synergistically with anticancer drugs, we therefore investigated whether dopamine can increase the efficacies of these drugs.

Experimental Design: The effect of dopamine was investigated in human breast cancer–(MCF-7) and colon (HT29) cancer–bearing mice. Experimental groups received either dopamine or doxorubicin or dopamine plus doxorubicin in MCF-7 tumor-bearing mice, and either dopamine or 5-fluorouracil or dopamine plus 5-fluorouracil in HT29-bearing mice. Thereafter, tumor growth, angiogenesis, tumor cell apoptosis, life span, and the effect of dopamine on the growth and survival of tumor cells in vitro were determined. Finally, the effects of dopamine on tumor vascular permeability; on VEGF receptor-2, mitogen-activated protein kinase, and focal adhesion kinase phosphorylation; and also on the proliferation and migration of tumor endothelial cells were investigated.

Results: Dopamine, in combination with anticancer drugs, significantly inhibited tumor growth and increased the life span when compared with treatment with dopamine or anticancer drugs alone. Dopamine had no direct effects on the growth and survival of tumor cells. The antiangiogenic action of dopamine was mediated by inhibiting proliferation and migration of tumor endothelial cells through suppression of VEGF receptor-2, mitogen-activated protein kinase, and focal adhesion kinase phosphorylation.

Conclusion: Our study shows that dopamine significantly enhances the efficacies of commonly used anticancer drugs and also indicates that an inexpensive drug like dopamine, which is being extensively used in the clinics, might have a role as an antiangiogenic agent for the treatment of breast and colon cancer.
Inverse Correlation between Tumoral Indoleamine 2,3-Dioxygenase Expression and Tumor-Infiltrating Lymphocytes in Endometrial Cancer: Its Association with Disease Progression and Survival
Authors: Ino Kazuhiko , Yamamoto Eiko , Shibata Kiyosumi , Kajiyama Hiroaki , Yoshida Norio , Terauchi Mikio , Nawa Akihiro , Nagasaka Tetsuro , Takikawa Osamu , Kikkawa Fumitaka
Published: April 2008

Purpose: Tumor escape from host immune systems is a crucial mechanism for disease progression. We recently showed that the immunosuppressive enzyme indoleamine 2,3-dioxygenase (IDO) is a prognostic indicator for endometrial cancer. The purpose of the present study was to investigate the relationship between IDO expression and tumor-infiltrating lymphocytes (TIL) or natural killer (NK) cells and to clarify their prognostic effect in endometrial cancer.

Experimental Design: Immunohistochemical staining for IDO expression in endometrial cancer tissues (n = 65) was done. Tumor-infiltrating CD3+ and CD8+ lymphocytes, as well as CD57+ NK cells, were counted in serial tissue sections.

Results: High IDO expression in tumor cells was found in 32 of 65 cases and was positively correlated with myometrial invasion, nodal metastasis, and lymph-vascular space involvement. We also found a significant correlation between high IDO expression and reduced numbers of CD3+, CD8+, and CD57+ cells infiltrating into both the tumor epithelium and stroma. Patients with high IDO expression, a low number of stromal CD3 (<60), low intraepithelial CD8 (<25), or low stromal CD8 (<40) had significantly impaired progression-free survival. On multivariate analysis, IDO expression and the number of stromal CD3+ TILs were independent prognostic factors for impaired progression-free survival.

Conclusions: Tumoral IDO expression correlated with a reduced number of TILs and NK cells in endometrial cancer, possibly contributing to disease progression and impaired clinical outcome. These findings suggest that targeting IDO to restore host antitumor immunity may be a therapeutic strategy for endometrial cancer.
Vascularization in Primary Breast Carcinomas: Its Prognostic Significance and Relationship with Tumor Cell Dissemination
Authors: Dhakal Hari Prasad , Naume Bjørn , Synnestvedt Marit , Borgen Elin , Kaaresen Rolf , Schlichting Ellen , Wiedswang Gro , Bassarova Assia , Giercksky Karl-Erik , Nesland Jahn M.
Published: April 2008

Purpose: The interaction between tumor cells, stroma, and endothelial cells is important for the dissemination of tumor cells. The aim of the present study is to examine vascularity in primary breast carcinomas and its prognostic significance and relationship with tumor cell dissemination.

Experimental Design: A total of 498 invasive breast carcinomas were analyzed. Representative tumor sections were stained for CD34 and CD105, and vascularity was quantified by the Chalkley method. The relationship between Chalkley counts, vascular invasion, disseminated tumor cells (DTC) in the bone marrow, other clinicopathologic variables, and clinical outcome was evaluated.

Results: High vascular grades determined by Chalkley counts were significantly associated with shorter distant disease–free survival and breast cancer–specific survival in all patients (P < 0.001, log-rank) and in node-negative patients not receiving adjuvant systemic therapy (P < 0.05). In multivariate analysis, both CD34 and CD105 Chalkley counts showed prognostic significance for distant disease–free survival (P = 0.014 and P = 0.026), whereas CD34 also showed prognostic significance for breast cancer–specific survival (P = 0.007). Vascular invasion and DTCs in the bone marrow showed independent prognostic significance. DTC did not discriminate survival for CD34 low Chalkley counts, whereas a very poor prognosis was observed for DTC-positive patients with high CD34 counts. In node-negative patients not receiving systemic chemotherapy, high CD34 and high CD105 counts in combination identified patients with unfavorable outcome, as opposed to all other CD34/CD105 combinations.

Conclusions: Improved identification of risk groups could be obtained by adding CD34 and CD105 vascular analysis to DTC, vascular invasion, and other primary tumor factors. This may facilitate the selection of candidates for adjuvant systemic therapy.
Treatment of Cancer with a Novel Dual-Targeted Conditionally Replicative Adenovirus Armed with mda-7/IL-24 Gene
Authors: Luo Jingjing , Xia Qingmei , Zhang Rui , Lv Chen , Zhang Wei , Wang Yingxin , Cui Qiang , Liu Li , Cai Rong , Qian Cheng
Published: April 2008

Purpose: Recent studies showed that oncolytic adenoviruses not only have capacity for destruction of tumors but also can be used as potential vectors to express therapeutic genes for therapy of cancer. However, better specificity and mode of transgene expression are required to improve the efficacy and safety if this vector is applied for clinical application.

Experimental Design: In this study, we have created adenoviral replication-based transgene expression system by replacement of 6.7K/gp19K of E3 genes with EGFP and IL-24 genes so that expression of transgenes should be controlled by adenoviral E3 promoter. Transgene expression, viral replication capacity, and cytotoxicity have been studied in tumor and normal cells. Antitumor efficacy was evaluated in animal model with established tumor.

Results: Our data showed that expression of IL-24 could be detected at 6 h and reached the maximal level at 48 h after infection in tumor cells. The expression level was 14 times higher than that induced by cytomegalovirus promoter. Low level of IL-24 could be detected in normal cells only until 72 h after infection. The substitution of 6.7K/gp19K of E3 genes with transgenes did not affect viral replication in tumor cells. Strong cytotoxicity was observed only in tumor cells after infection with AdCN205-IL-24. Treatment of the established tumors induced high level of local expression of IL-24 in tumor cells and resulted in tumor regression.

Conclusions: Our data showed that AdCN205-IL-24 can provide potent and safe vector for the therapy of cancer.
Epidermal Growth Factor Receptor Controls Flat Dysplastic Aberrant Crypt Foci Development and Colon Cancer Progression in the Rat Azoxymethane Model
Authors: Dougherty Urszula , Sehdev Amikar , Cerda Sonia , Mustafi Reba , Little Nathaniel , Yuan Weihua , Jagadeeswaran Sujatha , Chumsangsri Anusara , Delgado Jorge , Tretiakova Maria , Joseph Loren , Hart John , Cohen Ezra E.W. , Aluri Lata , Fichera Alessandro , Bissonnette Marc
Published: April 2008

Purpose: Colonic carcinogenesis deranges growth-regulating epidermal growth factor receptors (EGFR). We previously showed that EGFR signals were up-regulated in human aberrant crypt foci (ACF), putative colon cancer precursors. The azoxymethane model of colon cancer recapitulates many aspects of human colonic tumors. Recent studies indicate that flat dysplastic ACF with increased β-catenin are tumor precursors in this model. We asked, therefore, if EGFR signals are required for flat dysplastic ACF development and cancer progression.

Experimental Design: Rats received azoxymethane or saline, and standard chow or chow supplemented with gefitinib, an EGFR inhibitor, for 44 weeks. EGFR signals were quantified in normal colon, flat ACF, and tumors by computerized analysis of immunostains and Western blots. K-ras mutations were assessed by PCR and mRNA for egfr ligands by quantitative real-time PCR.

Results: EGFR inhibition with gefitinib decreased the incidence of flat dysplastic ACF from 66% to 36% and tumors from 71% to 22% (P < 0.05). This inhibitor also reduced the overexpressions of cyclin D1 and Cox-2 in flat ACF. Furthermore, in flat ACF, EGFR blockade decreased the up-regulation of c-Jun, FosB, phosphorylated active signal transducers and activators of transcription 3, and CCAAT/enhancer binding protein-β, potential regulators of cyclin D1 and Cox-2. In colonic tumors, EGFR blockade significantly decreased angiogenesis, proliferation, and progression while also increasing apoptosis (P < 0.05). Gefitinib also inhibited the activations of extracellular signal–regulated kinase, Src, and AKT pathways in tumors.

Conclusions: We have shown for the first time that EGFR promotes the development of flat dysplastic ACF and the progression of malignant colonic tumors. Furthermore, we have mechanistically identified several transcription factors and their targets as EGFR effectors in colonic carcinogenesis.
Sensitizing estrogen receptor–negative breast cancer cells to tamoxifen with OSU-03012, a novel celecoxib-derived phosphoinositide-dependent protein kinase-1/Akt signaling inhibitor
Authors: Weng Shu-Chuan , Kashida Yoko , Kulp Samuel K. , Wang Dasheng , Brueggemeier Robert W. , Shapiro Charles L. , Chen Ching-Shih
Published: April 2008

Tamoxifen is a mainstay in the treatment of estrogen receptor (ER)–positive breast cancer patients. Although the efficacy of tamoxifen has been attributed to induction of tumor cell growth arrest and apoptosis by inhibition of ER signaling, recent evidence indicates that tamoxifen possesses ER-independent antitumor activities. Here, we use OSU-03012, a small-molecule inhibitor of phosphoinositide-dependent protein kinase-1 (PDK-1) to address the hypothesis that PDK-1/Akt signaling represents a therapeutically relevant target to sensitize ER-negative breast cancer to tamoxifen. OSU-03012 sensitized both ER-positive MCF-7 and ER-negative MDA-MB-231 cells to the antiproliferative effects of tamoxifen in an ER-independent manner. Flow cytometric analysis of phosphatidylserine externalization revealed that this augmented suppression of cell viability was attributable to a marked enhancement of tamoxifen-induced apoptosis by OSU-03012. Mechanistically, this OSU-03012-mediated sensitization was associated with suppression of a transient tamoxifen-induced elevation of Akt phosphorylation and enhanced modulation of the functional status of multiple Akt downstream effectors, including FOXO3a, GSK3α/β, and p27. The growth of established MDA-MB-231 tumor xenografts was suppressed by 50% after oral treatment with the combination of tamoxifen (60 mg/kg) and OSU-03012 (100 mg/kg), whereas OSU-03012 and tamoxifen alone suppressed growth by 30% and 0%, respectively. These findings indicate that the inhibition of PDK-1/Akt signaling to sensitize ER-negative breast cancer cells to the ER-independent antitumor activities of tamoxifen represents a feasible approach to extending the use of tamoxifen to a broader population of breast cancer patients. Considering the urgent need for novel therapeutic strategies for ER-negative breast cancer patients, this combinatorial approach is worthy of continued investigation. [Mol Cancer Ther 2008;7(4):800–8]
SUMOylation of HMGA2: selective destabilization of promyelocytic leukemia protein via proteasome
Authors: Cao Xuefei , Clavijo Carlos , Li Xu , Lin H. Helen , Chen Yuan , Shih Hsiu-Ming , Ann David K.
Published: April 2008

The HMGA2 architectural protein functions in a variety of cellular processes, such as cell growth, transcription regulation, neoplastic transformation, and progression. Up-regulation of HMGA2 protein is observed in many tumors and is associated with advanced cancers with poor prognoses. Although the expression and biochemical properties of HMGA2 protein are regulated by microRNA and phosphorylation, it is unknown whether HMGA2 activity can also be regulated by SUMOylation, and that is what is investigated in this report. We identified HMGA2 as a SUMOylation target and showed that the expression of wild-type HMGA2, but not SUMOylation-defective HMGA2(2K/R), selectively lowered the steady-state level of PML protein. Consequently, the HMGA2-elicited PML down-regulation rendered a reduction in the average number of PML nuclear bodies per cell and the volume of PML assembled per PML nuclear body. Using small interfering RNA to suppress endogenous ubiquitin expression and proteasome inhibitor to repress ubiquitin-mediated protein degradation, we showed that HMGA2 confers PML down-regulation through ubiquitin-proteasome–dependent protein degradation. Importantly, arsenic trioxide treatment stimulated HMGA2 SUMOylation, leading to the formation of HMGA2 nuclear foci surrounding PML nuclear bodies and the stimulation of PML degradation. Collectively, our results unveil a previously unrecognized effect by HMGA2 on the modulation of PML protein level, providing a novel mechanism underlying HMGA2 function and underscoring the molecular basis for oncogenic progression by HMGA2. [Mol Cancer Ther 2008;7(4):923–34]
Molecular analysis of metaplastic breast carcinoma: high EGFR copy number via aneusomy
Authors: Gilbert Judith A. , Goetz Matthew P. , Reynolds Carol A. , Ingle James N. , Giordano Karin F. , Suman Vera J. , Blair Hilary E. , Jenkins Robert B. , Lingle Wilma L. , Reinholz Monica M. , Adjei Alex A. , Ames Matthew M.
Published: April 2008

Metaplastic breast carcinoma, a rare tumor composed of adenocarcinomatous and nonglandular growth patterns, is characterized by a propensity for distant metastases and resistance to standard anticancer therapies. We sought confirmation that this tumor is a basal-like breast cancer, expressing epidermal growth factor receptor (EGFR) and stem cell factor receptor (KIT). EGFR activating mutations and high copy number (associated with response to tyrosine kinase inhibitor gefitinib) and KIT activating mutations (associated with imatinib sensitivity) were then investigated. Seventy-seven metaplastic cases were identified (1976-2006); 38 with tumor blocks available underwent pathologic confirmation before EGFR and KIT immunohistochemical analyses. A tissue microarray of malignant glandular and metaplastic elements was constructed and analyzed immunohistochemically for cytokeratin 5/6, estrogen receptor, progesterone receptor, and p63, and by fluorescence in situ hybridization for EGFR and HER-2/neu. DNA isolated from individual elements was assessed for EGFR and KIT activating mutations. All assessable cases were negative for estrogen receptor, progesterone receptor, and (except one) HER2. The majority were positive for cytokeratin 5/6 (58%), p63 (59%), and EGFR overexpression (66%); 24% were KIT positive. No EGFR or KIT activating mutations were present; 26% of the primary metaplastic breast carcinomas were fluorescence in situ hybridization-positive, displaying high EGFR copy number secondary to aneusomy (22%) and amplification (4%). We report here that metaplastic breast carcinoma is a basal-like breast cancer lacking EGFR and KIT activating mutations but exhibiting high EGFR copy number (primarily via aneusomy), suggesting that EGFR tyrosine kinase inhibitors should be evaluated in this molecular subset of breast carcinomas. [Mol Cancer Ther 2008;7(4):944–51]
Genome-wide DNA copy number predictors of lapatinib sensitivity in tumor-derived cell lines
Authors: Greshock Joel , Cheng Jie , Rusnak David , Martin Anne Marie , Wooster Richard , Gilmer Tona , Lee Kwan , Weber Barbara L. , Zaks Tal
Published: April 2008

A common aim of pharmacogenomic studies that use genome-wide assays on panels of cancers is the unbiased discovery of genomic alterations that are associated with clinical outcome and drug response. Previous studies of lapatinib, a selective dual-kinase inhibitor of epidermal growth factor receptor (EGFR) and HER2 tyrosine kinases, have shown predictable relationships between the activity of these target genes and response. Under the hypothesis that additional genes may play a role in drug sensitivity, a predictive model for lapatinib response was constructed from genome-wide DNA copy number data from 24 cancer cell lines. An optimal predictive model which consists of aberrations at nine distinct genetic loci, includes gains of HER2, EGFR, and loss of CDKN2A. This model achieved an area under the receiver operating characteristic curve of ∼0.85 (80% confidence interval, 0.70–0.98; P < 0.01), and correctly classified the sensitivity status of 8 of 10 head and neck cancer cell lines. This study shows that biomarkers predictive for lapatinib sensitivity, including the previously described copy number gains of EGFR and HER2, can be discovered using novel genomic assays in an unbiased manner. Furthermore, these results show the utility of DNA copy number profiles in pharmacogenomic studies. [Mol Cancer Ther 2008;7(4):935–43]
The proximal promoter region of the human vascular endothelial growth factor gene has a G-quadruplex structure that can be targeted by G-quadruplex–interactive agents
Authors: Sun Daekyu , Liu Wei-Jun , Guo Kexiao , Rusche Jadrian J. , Ebbinghaus Scot , Gokhale Vijay , Hurley Laurence H.
Published: April 2008

Previous studies on the functional analysis of the human vascular endothelial growth factor (VEGF) promoter using the full-length VEGF promoter reporter revealed that the proximal 36-bp region (−85 to −50 relative to transcription initiation site) is essential for basal or inducible VEGF promoter activity in several human cancer cells. This region consists of a polypurine (guanine) tract that contains four runs of at least three contiguous guanines separated by one or more bases, thus conforming to a general motif capable of forming an intramolecular G-quadruplex. Here, we show that the G-rich strand in this region is able to form an intramolecular propeller-type parallel-stranded G-quadruplex structure in vitro by using the electrophoretic mobility shift assay, dimethyl sulfate footprinting technique, the DNA polymerase stop assay, circular dichroism spectroscopy, and computer-aided molecular modeling. Two well-known G-quadruplex–interactive agents, TMPyP4 and Se2SAP, stabilize G-quadruplex structures formed by this sequence in the presence of a potassium ion, although Se2SAP is at least 10-fold more effective in binding to the G-quadruplex than TMPyP4. Between these two agents, Se2SAP better suppresses VEGF transcription in different cancer cell lines, including HEC1A and MDA-MB-231. Collectively, our results provide evidence that specific G-quadruplex structures can be formed in the VEGF promoter region, and that the transcription of this gene can be controlled by ligand-mediated G-quadruplex stabilization. Our results also provide further support for the idea that G-quadruplex structures may play structural roles in vivo and therefore might provide insight into novel methodologies for rational drug design. [Mol Cancer Ther 2008;7(4):880–9]
Histone tail modifications and noncanonical functions of histones: perspectives in cancer epigenetics
Authors: Hadnagy Annamaria , Beaulieu Raymond , Balicki Danuta
Published: April 2008

Over the past few years, the histone deacetylase (HDAC) inhibitors have occupied an important place in the effort to develop novel, but less toxic, anticancer therapy. HDAC inhibitors block HDACs, which are the enzymes responsible for histone deacetylation, and therefore they modulate gene expression. The cellular effects of HDAC inhibitors include growth arrest and the induction of differentiation. Early successes in cancer therapeutics obtained using these drugs alone or in combination with other anticancer drugs emphasize the important place of posttranslational modifications of histones in cancer therapy. Histone tail modifications along with DNA methylation are the most studied epigenetic events related to cancer progression. Moreover, extranuclear functions of histones have also been described. Because HDAC inhibitors block HDACs and thereby increase histone acetylation, we propose a model wherein exogenous acetylated histones or other related acetylated proteins that are introduced into the nucleus become HDAC substrates and thereby compete with endogenous histones for HDACs. This competition may lead to the increased acetylation of the endogenous histones, as in the case of HDAC inhibitor therapy. Moreover, other mechanisms of action, such as binding to chromatin and modulating gene expression, are also possible for exogenously introduced histones. [Mol Cancer Ther 2008;7(4):740–8]
Effects of Off-Pump Versus On-Pump Coronary Artery Bypass Grafting on Early and Late Right Ventricular Function
Authors: Pegg Tammy J. , Selvanayagam Joseph B. , Karamitsos Theodoros D. , Arnold Ranjit J. , Francis Jane M. , Neubauer Stefan , Taggart David P.
Published: April 2008

Background—

Off-pump CABG (OPCABG) results in better preservation of left ventricular function in the perioperative period than conventional on-pump CABG (ONCABG); however, evidence is conflicting as to the effect of OPCABG and ONCABG on right ventricular (RV) function, possibly because of the complexity involved in measuring this.

Methods and Results—

In a single-center randomized pilot study, 60 patients with normal left ventricular function undergoing CABG were randomly assigned to OPCABG or ONCABG. Patients underwent cardiac magnetic resonance imagine for assessment of RV function preoperatively, early postoperatively, and at 6 months after surgery. Fifty-one patients completed the first 2 scans, and 47 completed all 3 scans. Preoperative characteristics and RV function did not differ significantly between the 2 groups (mean±SD): RV stroke volume index was 49±10 mL/m
2
for OPCABG and 49±16 mL/m
2
for ONCABG. After surgery, RV stroke volume index fell to 36±7 mL/m
2
in the OPCABG group and 39±11 mL/m
2
in the ONCABG group, but this did not differ significantly between the 2 groups (
P
=0.41). All markers of RV function recovered to preoperative levels by 6 months, with no long-term difference between the surgical techniques.

Conclusions—

RV function is impaired early after surgery but recovers by 6 months. The changes were similar in both the OPCABG and ONCABG groups.
Genetic Components of the Circadian Clock Regulate Thrombogenesis In Vivo
Authors: Westgate Elizabeth J. , Cheng Yan , Reilly Dermot F. , Price Tom S. , Walisser Jacqueline A. , Bradfield Christopher A. , FitzGerald Garret A.
Published: April 2008

Background—

Myocardial infarction, stroke, and sudden death undergo diurnal variation. Although genes relevant to hemostasis and vascular integrity undergo circadian oscillation, the role of the molecular clock in thrombotic events remains to be established.

Methods and Results—

A diurnal variation in the time to thrombotic vascular occlusion (TTVO) subsequent to a photochemical injury was observed in wild-type mice: TTVO varied from 24.6±2.7 minutes at zeitgeber time (ZT) 2 to 40.3±4.3 minutes at ZT8, 24.3±2.3 minutes at ZT14, and 31.0±4.4 minutes at ZT20. This pattern was disrupted or altered when core clock genes—BMAL1, CLOCK, and NPAS2—were mutated or deleted. Mutation of CLOCK abolished the diurnal variation in TTVO, whereas deletion of NPAS2 altered its temporal pattern. NPAS2 deletion prolonged TTVO and reduced blood pressure irrespective of clock time. Global BMAL1 deletion shortened TTVO at ZT8, and the diurnal variation in TTVO, but not in systemic blood pressure, was disrupted in mice in which BMAL1 had been selectively deleted in endothelium.

Conclusions—

Key components of the molecular clock regulate the response to a thrombogenic stimulus in vivo. Such a phenomenon may interact with environmental variables, and together with the influence of these genes on blood pressure may contribute to the diurnal variation in cardiovascular events observed in humans.
Inflammation, Oxidative Stress, and Repair Capacity of the Vascular Endothelium in Obstructive Sleep Apnea
Authors: Jelic Sanja , Padeletti Margherita , Kawut Steven M. , Higgins Christopher , Canfield Stephen M. , Onat Duygu , Colombo Paolo C. , Basner Robert C. , Factor Phillip , LeJemtel Thierry H.
Published: April 2008

Background—

Indirect evidence implicates endothelial dysfunction in the pathogenesis of vascular diseases associated with obstructive sleep apnea (OSA). We investigated directly whether dysfunction and inflammation occur in vivo in the vascular endothelium of patients with OSA. The effects of continuous positive airway pressure (CPAP) therapy on endothelial function and repair capacity were assessed.

Methods and Results—

Thirty-two patients with newly diagnosed OSA and 15 control subjects were studied. Proteins that regulate basal endothelial nitric oxide (NO) production (endothelial NO synthase [eNOS] and phosphorylated eNOS) and inflammation (cyclooxygenase-2 and inducible NOS) and markers of oxidative stress (nitrotyrosine) were quantified by immunofluorescence in freshly harvested venous endothelial cells before and after 4 weeks of CPAP therapy. Vascular reactivity was measured by flow-mediated dilation. Circulating endothelial progenitor cell levels were quantified to assess endothelial repair capacity. Baseline endothelial expression of eNOS and phosphorylated eNOS was reduced by 59% and 94%, respectively, in patients with OSA compared with control subjects. Expression of both nitrotyrosine and cyclooxygenase-2 was 5-fold greater in patients with OSA than in control subjects, whereas inducible NOS expression was 56% greater. Expression of eNOS and phosphorylated eNOS significantly increased, whereas expression of nitrotyrosine, cyclooxygenase-2, and inducible NOS significantly decreased in patients who adhered to CPAP ≥4 hours daily. Baseline flow-mediated dilation and endothelial progenitor cell levels were lower in patients than in control subjects, and both significantly increased in patients who adhered to CPAP ≥4 hours daily.

Conclusions—

OSA directly affects the vascular endothelium by promoting inflammation and oxidative stress while decreasing NO availability and repair capacity. Effective CPAP therapy is associated with the reversal of these alterations.
Spontaneous Myocardial Infarction in Mice Lacking All Nitric Oxide Synthase Isoforms
Authors: Nakata Sei , Tsutsui Masato , Shimokawa Hiroaki , Suda Osamu , Morishita Tsuyoshi , Shibata Kiyoko , Yatera Yasuko , Sabanai Ken , Tanimoto Akihide , Nagasaki Machiko , Tasaki Hiromi , Sasaguri Yasuyuki , Nakashima Yasuhide , Otsuji Yutaka , Yanagihara Nobuyuki
Published: April 2008

Background—

The roles of nitric oxide (NO) in the cardiovascular system have been investigated extensively in pharmacological studies with NO synthase (NOS) inhibitors and in studies with NOS isoform–deficient mice. However, because of the nonspecificity of the NOS inhibitors and the compensatory interactions among NOS isoforms (nNOS, iNOS, and eNOS), the ultimate roles of endogenous NO derived from the entire NOS system are still poorly understood. In this study, we examined this point in mice deficient in all 3 NOS isoforms (triply n/i/eNOS
−/−
mice) that we have recently developed.

Methods and Results—

The triply n/i/eNOS
−/−
mice, but not singly eNOS
−/−
mice, exhibited markedly reduced survival, possibly due to spontaneous myocardial infarction accompanied by severe coronary arteriosclerotic lesions. Furthermore, the triply n/i/eNOS
−/−
mice manifested phenotypes that resembled metabolic syndrome in humans, including visceral obesity, hypertension, hypertriglyceridemia, and impaired glucose tolerance. Importantly, activation of the renin-angiotensin system was noted in the triply n/i/eNOS
−/−
mice, and long-term oral treatment with an angiotensin II type 1 receptor blocker significantly suppressed coronary arteriosclerotic lesion formation and the occurrence of spontaneous myocardial infarction and improved the prognosis of those mice, along with ameliorating the metabolic abnormalities.

Conclusions—

These results provide the first direct evidence that genetic disruption of the whole NOS system causes spontaneous myocardial infarction associated with multiple cardiovascular risk factors of metabolic origin in mice in vivo through the angiotensin II type 1 receptor pathway, demonstrating the critical role of the endogenous NOS system in maintaining cardiovascular and metabolic homeostasis.