bluuebunny/crossref_metadata_2025 huggingface dataset:
Monoclonal Antibody Blockade of the Human Eag1 Potassium Channel Function Exerts Antitumor Activity
Authors: Gómez-Varela David , Zwick-Wallasch Esther , Knötgen Hendrik , Sánchez Araceli , Hettmann Thore , Ossipov Dmitri , Weseloh Rüdiger , Contreras-Jurado Constanza , Rothe Mike , Stühmer Walter , Pardo Luis A.
Published: August 2007

The potassium channel ether à go-go has been directly linked to cellular proliferation and transformation, although its physiologic role(s) are as of yet unknown. The specific blockade of human Eag1 (hEag1) may not only allow the dissection of the role of the channel in distinct physiologic processes, but because of the implication of hEag1 in tumor biology, it may also offer an opportunity for the treatment of cancer. However, members of the potassium channel superfamily are structurally very similar to one another, and it has been notoriously difficult to obtain specific blockers for any given channel. Here, we describe and validate the first rational design of a monoclonal antibody that selectively inhibits a potassium current in intact cells. Specifically blocking hEag1 function using this antibody inhibits tumor cell growth both in vitro and in vivo. Our data provide a proof of concept that enables the generation of functional antagonistic monoclonal antibodies against ion channels with therapeutic potential. The particular antibody described here, as well as the technique developed to make additional functional antibodies to Eag1, makes it possible to evaluate the potential of the channel as a target for cancer therapy. [Cancer Res 2007;67(15):7343–49]
Guggulsterone-Induced Apoptosis in Human Prostate Cancer Cells Is Caused by Reactive Oxygen Intermediate–Dependent Activation of c-Jun NH2-Terminal Kinase
Authors: Singh Shivendra V. , Choi Sunga , Zeng Yan , Hahm Eun-Ryeong , Xiao Dong
Published: August 2007

Guggulsterone, a constituent of Indian Ayurvedic medicinal plant Commiphora mukul, causes apoptosis in cancer cells but the sequence of events leading to cell death is poorly understood. We now show that guggulsterone-induced cell death in human prostate cancer cells is caused by reactive oxygen intermediate (ROI)–dependent activation of c-Jun NH2-terminal kinase (JNK). Exposure of PC-3 and LNCaP cells to apoptosis inducing concentrations of guggulsterone resulted in activation of JNK and p38 mitogen-activated protein kinase (p38 MAPK) in both cell lines and activation of extracellular signal-regulated kinase 1/2 (ERK1/2) in LNCaP cells. The guggulsterone-induced apoptosis in PC-3/LNCaP cells was partially but statistically significantly attenuated by pharmacologic inhibition (SP600125) as well as genetic suppression of JNK activation. On the other hand, pharmacologic inhibition of p38 MAPK activation in PC-3 or LNCaP cells (SB202190) and ERK1/2 activation in LNCaP cells (PD98059) did not protect against guggulsterone-induced cell death. The guggulsterone treatment caused generation of ROI in prostate cancer cells but not in a normal prostate epithelial cell line (PrEC), which was also resistant to guggulsterone-mediated JNK activation. The guggulsterone-induced JNK activation as well as cell death in prostate cancer cells was significantly attenuated by overexpression of catalase and superoxide dismutase. In addition, guggulsterone treatment resulted in a decrease in protein level and promoter activity of androgen receptor in LNCaP cells. In conclusion, the present study reveals that the guggulsterone-induced cell death in human prostate cancer cells is regulated by ROI-dependent activation of JNK and guggulsterone inhibits promoter activity of androgen receptor. [Cancer Res 2007;67(15):7439–49]
Profiling Microdissected Epithelium and Stroma to Model Genomic Signatures for Cervical Carcinogenesis Accommodating for Covariates
Authors: Gius David , Funk Margo C. , Chuang Eric Y. , Feng Sheng , Huettner Phyllis C. , Nguyen Loan , Bradbury C. Matthew , Mishra Mark , Gao Shuping , Buttin Barbara M. , Cohn David E. , Powell Matthew A. , Horowitz Neil S. , Whitcomb Bradford P. , Rader Janet S.
Published: August 2007

This study is the first comprehensive, integrated approach to examine grade-specific changes in gene expression along the entire neoplastic spectrum of cervical intraepithelial neoplasia (CIN) in the process of cervical carcinogenesis. This was accomplished by identifying gene expression signatures of disease progression using cDNA microarrays to analyze RNA from laser-captured microdissected epithelium and underlying stroma from normal cervix, graded CINs, cancer, and patient-matched normal cervical tissues. A separate set of samples were subsequently validated using a linear mixed model that is ideal to control for interpatient gene expression profile variation, such as age and race. These validated genes were ultimately used to propose a genomically based model of the early events in cervical neoplastic transformation. In this model, the CIN 1 transition coincides with a proproliferative/immunosuppression gene signature in the epithelium that probably represents the epithelial response to human papillomavirus infection. The CIN 2 transition coincides with a proangiogenic signature, suggesting a cooperative signaling interaction between stroma and tumor cells. Finally, the CIN 3 and squamous cell carcinoma antigen transition coincide with a proinvasive gene signature that may be a response to epithelial tumor cell overcrowding. This work strongly suggests that premalignant cells experience a series of microenvironmental stresses at the epithelium/stroma cell interface that must be overcome to progress into a transformed phenotype and identifies the order of these events in vivo and their association with specific CIN transitions. [Cancer Res 2007;67(15):7113–23]
Sequential Loss of Tumor Vessel Pericytes and Endothelial Cells after Inhibition of Platelet-Derived Growth Factor B by Selective Aptamer AX102
Authors: Sennino Barbara , Falcón Beverly L. , McCauley Dilara , Le Tom , McCauley Thomas , Kurz Jeffrey C. , Haskell Amy , Epstein David M. , McDonald Donald M.
Published: August 2007

Inhibition of platelet derived growth factor (PDGF) can increase the efficacy of other cancer therapeutics, but the cellular mechanism is incompletely understood. We examined the cellular effects on tumor vasculature of a novel DNA oligonucleotide aptamer (AX102) that selectively binds PDGF-B. Treatment with AX102 led to progressive reduction of pericytes, identified by PDGF receptor β, NG2, desmin, or α-smooth muscle actin immunoreactivity, in Lewis lung carcinomas. The decrease ranged from 35% at 2 days, 63% at 7 days, to 85% at 28 days. Most tumor vessels that lacked pericytes at 7 days subsequently regressed. Overall tumor vascularity decreased 79% over 28 days, without a corresponding decrease in tumor size. Regression of pericytes and endothelial cells led to empty basement membrane sleeves, which were visible at 7 days, but only 54% remained at 28 days. PDGF-B inhibition had a less pronounced effect on pancreatic islet tumors in RIP-Tag2 transgenic mice, where pericytes decreased 47%, vascularity decreased 38%, and basement membrane sleeves decreased 21% over 28 days. Taken together, these findings show that inhibition of PDGF-B signaling can lead to regression of tumor vessels, but the magnitude is tumor specific and does not necessarily retard tumor growth. Loss of pericytes in tumors is an expected direct consequence of PDGF-B blockade, but reduced tumor vascularity is likely to be secondary to pericyte regression. [Cancer Res 2007;67(15):7358–67]
Enhanced Peritoneal Ovarian Tumor Dissemination by Tissue Transglutaminase
Authors: Satpathy Minati , Cao Liyun , Pincheira Roxana , Emerson Robert , Bigsby Robert , Nakshatri Harikrishna , Matei Daniela
Published: August 2007

Tissue transglutaminase (TG2) is involved in Ca2+-dependent aggregation and polymerization of proteins. We previously reported that TG2 mRNA is up-regulated in epithelial ovarian cancer (EOC) cells compared with normal ovarian epithelium. Here, we show overexpression of the TG2 protein in ovarian cancer cells and tumors and its secretion in ascites fluid and define its role in EOC. By stable knockdown and overexpression, we show that TG2 enhances EOC cell adhesion to fibronectin and directional cell migration. This phenotype is preserved in vivo, where the pattern of tumor dissemination in the peritoneal space is dependent on TG2 expression levels. TG2 knockdown diminishes dissemination of tumors on the peritoneal surface and mesentery in an i.p. ovarian xenograft model. This phenotype is associated with deficient β1 integrin-fibronectin interaction, leading to weaker anchorage of cancer cells to the peritoneal matrix. Highly expressed in ovarian tumors, TG2 facilitates i.p. tumor dissemination by enhancing cell adhesion to the extracellular matrix and modulating β1 integrin subunit expression. [Cancer Res 2007;67(15):7194–202]
Identification of Pax5 as a Target of MTA1 in B-Cell Lymphomas
Authors: Balasenthil Seetharaman , Gururaj Anupama E. , Talukder Amjad H. , Bagheri-Yarmand Rozita , Arrington Ty , Haas Brian J. , Braisted John C. , Kim Insun , Lee Norman H. , Kumar Rakesh
Published: August 2007

Previously, we have shown that metastasis-associated protein 1 (MTA1) overexpression in transgenic mice was accompanied by high incidence of spontaneous B-cell lymphomas including diffuse large B-cell lymphomas (DLBCL). To understand the molecular basis of lymphoma in MTA1-transgenic (MTA1-TG) mice, we wished to identify a putative MTA1 target with a causal role in B-cell lymphogenesis. Using chromatin immunoprecipitation assays, we identified paired box gene 5 (Pax5), a molecule previously implicated in B-cell lymphogenesis, as a potential downstream effector of MTA1. Lymphomas from MTA1-TG mice also showed up-regulation of Pax5. We also found that MTA1 acetylated on Lys626 interacted with p300 histone acetyltransferase, and that acetylated MTA1 was recruited to the Pax5 promoter to stimulate Pax5 transcription. Global gene profiling identified down-regulation of a set of genes, including those downstream of Pax5 and directly implicated in the B-cell lymphogenesis. Significance of these murine studies was established by evidence showing a widespread up-regulation of both MTA1 and Pax5 in DLBCL from humans. These observations provide in vivo genetic evidence for a role of MTA1 in lymphomagenesis. [Cancer Res 2007;67(15):7132–8]
Down-regulation of the Sodium/Iodide Symporter Explains 131I-Induced Thyroid Stunning
Authors: Nordén Madeleine M. , Larsson Fredrik , Tedelind Sofia , Carlsson Therese , Lundh Charlotta , Forssell-Aronsson Eva , Nilsson Mikael
Published: August 2007

131I radiation therapy of differentiated thyroid cancer may be compromised by thyroid stunning (i.e., a paradoxical inhibition of radioiodine uptake caused by radiation from a pretherapeutic diagnostic examination). The stunning mechanism is yet uncharacterized at the molecular level. We therefore investigated whether the expression of the sodium/iodide symporter (NIS) gene is changed by irradiation using 131I. Confluent porcine thyroid cells on filter were stimulated with thyroid-stimulating hormone (TSH; 1 milliunit/mL) or insulin-like growth factor-I (IGF-I; 10 ng/mL) and simultaneously exposed to 131I in the culture medium for 48 h, porcine NIS mRNA was quantified by real-time reverse transcription-PCR using 18S as reference, and transepithelial iodide transport was monitored using 125I− as tracer. TSH increased the NIS expression >100-fold after 48 h and 5- to 20-fold after prolonged stimulation. IGF-I enhanced the NIS transcription at most 15-fold but not until 5 to 7 days. 131I irradiation (7.5 Gy) decreased both TSH-stimulated and IGF-I–stimulated NIS transcription by 60% to 90% at all investigated time points. TSH and IGF-I stimulated NIS synergistically 15- to 60-fold after 5 days. NIS expression was reduced by 131I also in costimulated cells, but the transcription level remained higher than in nonirradiated cells stimulated with TSH alone. Changes in NIS mRNA always correlated with altered 125I− transport in cultures with corresponding treatments. It is concluded that down-regulation of NIS is the likely explanation of 131I-induced thyroid stunning. Enhanced NIS expression by synergistically acting agents (TSH and IGF-I) partly prevents the loss of iodide transport expected from a given absorbed dose, suggesting that thyroid stunning might be pharmacologically treatable. [Cancer Res 2007;67(15):7512–17]
Combined Natural Killer T-Cell–Based Immunotherapy Eradicates Established Tumors in Mice
Authors: Teng Michele W.L. , Westwood Jennifer A. , Darcy Phillip K. , Sharkey Janelle , Tsuji Moriya , Franck Richard W. , Porcelli Steven A. , Besra Gurdyal S. , Takeda Kazuyoshi , Yagita Hideo , Kershaw Michael H. , Smyth Mark J.
Published: August 2007

A rational monoclonal antibody (mAb)-based antitumor therapy approach has previously been shown to eradicate various established experimental and carcinogen-induced tumors in a majority of mice. This therapy comprised an agonistic mAb reactive with tumor necrosis factor–related apoptosis-inducing ligand receptor (DR5), expressed by tumor cells, an agonistic anti-CD40 mAb to mature dendritic cells, and an agonistic anti-4-1BB mAb to costimulate CD8+ T cells. Because agonists of CD40 have been toxic in patients, we were interested in substituting anti-CD40 mAb with other dendritic cell–maturing agents, such as glycolipid ligands recognized by invariant natural killer T (iNKT) cells. Here, we show that CD1d-restricted glycolipid ligands for iNKT cells effectively substitute for anti-CD40 mAb and reject established experimental mouse breast and renal tumors when used in combination with anti-DR5 and anti-4-1BB mAbs (termed “NKTMab” therapy). NKTMab therapy–induced tumor rejection was dependent on CD4+ and CD8+ T cells, NKT cells, and the cytokine IFN-γ. NKTMab therapy containing either α-galactosylceramide (α-GC) or α-C-galactosylceramide (α-c-GC) at high concentrations induced similar rates of tumor rejection in mice; however, toxicity was observed at the highest doses of α-GC (>250 ng/injection), limiting the use of this glycolipid. By contrast, even very low doses of α-c-GC (25 ng/injection) retained considerable antitumor activity when used in combination with anti-DR5/anti-4-1BB, and thus, α-c-GC showed a considerably greater therapeutic index. In summary, sequential tumor cell apoptosis and amplification of dendritic cell function by NKT cell agonists represents an exciting and novel approach for cancer treatment. [Cancer Res 2007;67(15):7495–504]
Cannabinoid Modulation of Kaposi's Sarcoma–Associated Herpesvirus Infection and Transformation
Authors: Zhang Xuefeng , Wang Jian Feng , Kunos George , Groopman Jerome E.
Published: August 2007

Kaposi's sarcoma–associated herpesvirus (KSHV; also named human herpesvirus 8) is necessary but not sufficient for the development of Kaposi's sarcoma. A variety of factors may contribute to the pathogenesis of Kaposi's sarcoma in addition to KSHV. Marijuana is a widely used recreational agent, and Δ9-tetrahydrocannabinol (Δ9-THC), the major active component of marijuana, is prescribed for medicinal use. To evaluate how cannabinoids may affect the pathogenesis of Kaposi's sarcoma, we studied primary human dermal microvascular endothelial cells (HMVEC) exposed to KSHV. There was an increased efficiency of KSHV infection in the presence of low doses of Δ9-THC. We also found that Δ9-THC increased the viral load in KSHV-infected HMVEC through activation of the KSHV lytic switch gene, the open reading frame 50. Furthermore, we observed that Δ9-THC stimulated expression of the KSHV-encoded viral G protein–coupled receptor and Kaposi's sarcoma cell proliferation. Our results indicate that Δ9-THC can enhance KSHV infection and replication and foster KSHV-mediated endothelial transformation. Thus, use of cannabinoids may place individuals at greater risk for the development and progression of Kaposi's sarcoma. [Cancer Res 2007;67(15):7230–7]
Isoobtusilactone A Induces Cell Cycle Arrest and Apoptosis through Reactive Oxygen Species/Apoptosis Signal-Regulating Kinase 1 Signaling Pathway in Human Breast Cancer Cells
Authors: Kuo Po-Lin , Chen Chung-Yi , Hsu Ya-Ling
Published: August 2007

This study is the first to investigate the anticancer effect of isoobtusilactone A (IOA) in two human breast cancer cell lines, MCF-7 and MDA-MB-231. IOA exhibited effective cell growth inhibition by inducing cancer cells to undergo G2-M phase arrest and apoptosis. Further investigation revealed that IOA's inhibition of cell growth was also evident in a nude mice model. Cell cycle blockade was associated with increased levels of p21 and reduced amounts of cyclin B1, cyclin A, cdc2, and cdc25C. IOA also enhanced the levels of inactivated phosphorylated cdc2 and cdc25C. IOA triggered the mitochondrial apoptotic pathway, as indicated by a change in Bax/Bcl-2 ratios, resulting in mitochondrial membrane potential loss, cytochrome c release, and caspase-9 activation. We also found that the generation of reactive oxygen species (ROS) is a critical mediator in IOA-induced cell growth inhibition. Enhancement of ROS by IOA activated apoptosis signal-regulating kinase 1 (ASK1) resulted in the increased activation of c-Jun NH2-terminal kinase and p38. Antioxidants EUK8 and N-acetyl cystenine significantly decreased apoptosis by inhibiting the ASK1 dephosphorylation at Ser967 and subsequently increased the interaction of ASK1 with thioredoxin or 14-3-3 proteins. Moreover, blocking ASK1 by small interfering RNA inhibition completely suppressed IOA-induced apoptosis. Taken together, these results imply a critical role for ROS and ASK1 in IOA's anticancer activity. [Cancer Res 2007;67(15):7406–20]
Combined Yeast β-Glucan and Antitumor Monoclonal Antibody Therapy Requires C5a-Mediated Neutrophil Chemotaxis via Regulation of Decay-Accelerating Factor CD55
Authors: Li Bing , Allendorf Daniel J. , Hansen Richard , Marroquin Jose , Cramer Daniel E. , Harris Claire L. , Yan Jun
Published: August 2007

Administration of a combination of yeast-derived β-glucan with antitumor monoclonal antibodies (mAb) has significant therapeutic efficacy in a variety of syngeneic murine tumor models. We have now tested this strategy using human carcinomas implanted in immunocompromised severe combined immunodeficient mice. Combined immunotherapy was therapeutically effective in vivo against NCI-H23 human non–small-cell lung carcinomas, but this modality was surprisingly ineffective against SKOV-3 human ovarian carcinomas. Whereas NCI-H23 tumors responded to this combination therapy with increased intratumoral neutrophil infiltration and C5a production, these responses were lacking in treated SKOV-3 tumors. Further results suggested that SKOV-3 tumors were protected by up-regulation of the membrane complement regulatory protein CD55 (decay-accelerating factor). Blockade of CD55 in vitro led to enhanced deposition of C activation product C3b and increased cytotoxicity mediated by β-glucan–primed neutrophils. In vivo, administration of anti-CD55 mAb along with β-glucan and anti–Her-2/neu mAb caused tumor regression and greatly improved long-term survival in animals bearing the previously resistant SKOV-3 tumors. This was accompanied by increased intratumoral neutrophil accumulation and C5a production. We conclude that CD55 suppresses tumor killing by antitumor mAb plus β-glucan therapy (and, perhaps, in other circumstances). These results suggest a critical role for CD55 to regulate iC3b and C5a release and in turn to influence the recruitment of β-glucan–primed neutrophils eliciting killing activity. [Cancer Res 2007;67(15):7421–30]
Tumor Angiogenesis: Cause or Consequence of Cancer?
Authors: Shchors Ksenya , Evan Gerard
Published: August 2007

Both tumors and normal tissues need a blood supply for oxygen, nutrients, and waste removal. However, whereas normal vasculature is hierarchically assembled into efficient networks of arteries, capillaries, and veins, the blood vessels of tumors are a mess—chaotic, leaky, inefficient, and barely making do. Why the difference? Do tumor vessels lack the signals to mature or, instead, is their maturation actively suppressed? What triggers and maintains tumor vasculature? In a recent study using a switchable Myc-driven mouse tumor model, we addressed these fundamental questions. We identified the inflammatory cytokine interleukin-1β as an essential initiating trigger of vascular endothelial growth factor–dependent angiogenesis. Here, we consider how kinetic studies using regulatable forms of Myc or other oncogenes can shed new light on the way tumors initiate and maintain their aberrant blood supplies. [Cancer Res 2007;67(15):7059–61]
Validation and Characterization of Human Kallikrein 11 as a Serum Marker for Diagnosis of Ovarian Carcinoma
Authors: McIntosh Martin W. , Liu Yan , Drescher Charles , Urban Nicole , Diamandis Eleftherios P.
Published: August 2007

Purpose: The serum tumor marker CA 125 is elevated in most clinically advanced ovarian carcinomas, and currently, one of the most promising early detection strategies for ovarian cancer uses CA 125 level in conjunction with imaging. However, CA 125 is elevated in only 50% of early-stage ovarian cancer and is often elevated in women with benign ovarian tumors and other gynecologic diseases. Additional markers may improve on its individual performance if they increase sensitivity and specificity and are less sensitive to other gynecologic conditions. The human kallikrein 11 (hK11) marker has been reported to have favorable predictive value for ovarian cancer, although, by itself, it may be inferior to CA 125.

Experimental Design: We here validate the performance of hK11 on an independent data set and further characterize its behavior in multiple types of controls. We also investigate its behavior when combined with CA 125 to form a composite marker. hK11 had not previously been evaluated on these serum samples. CA 125, hK11, and the composite marker were evaluated for their performance in identifying ovarian cancer and for temporal stability.

Results: hK11 significantly distinguished ovarian cancer cases from healthy controls and is less sensitive to benign ovarian disease than is CA 125.

Conclusion: We conclude that hK11 is a valuable new biomarker for ovarian cancer and its temporal stability implies that it may do even better when used in a longitudinal screening program for early detection.
Association of Expression Aberrances and Genetic Polymorphisms of Lysyl Oxidase with Areca-Associated Oral Tumorigenesis
Authors: Shieh Tzong-Ming , Lin Shu-Chun , Liu Chung-Ji , Chang Shu-Shin , Ku Ti-Hsuan , Chang Kuo-Wei
Published: August 2007

Purpose: Areca nut use is the major cause of oral squamous cell carcinoma (OSCC) in Southern Asians. Areca nut contains a high level of free copper ions. Lysyl oxidase (LOX) is a copper-activated enzyme critical for extracellular matrix organization. Contradictory evidence has been put forward to suggest that LOX may be either an oncogenic or a suppressive element. This study investigated the oncogenic significance of LOX in areca-associated OSCC.

Experimental Design: The expression assays and polymorphism analysis were done to know the clinicopathologic implications of LOX status in OSCC. Knockdown and overexpression experiments were conducted to know the phenotypic effects of LOX on OSCC cells.

Results: Up-regulation of LOX mRNA and LOX protein expression in OSCCs relative to adjacent oral mucosa was found. Precancerous lesions had the highest LOX mRNA expression. Areca nut extract up-regulated LOX expression in oral epithelial cells. Knockdown of LOX induced cellular migration and invasion, but it reduced the anchorage-independent growth and xenographic tumorigenesis of OSCC cells. The reduction of migration and invasion by LOX overexpression was partially rescued by blockage of LOX activity. The Arg158Gln polymorphism was associated with earlier clinical stage of OSCC. Wild-type LOX overexpression induced anchorage-independent growth in OSCC cells, but this was not for LOXArg158Gln overexpression.

Conclusion: LOX exerts oncogenic roles in areca-associated OSCC. This potential could be affected by the existence of LOX propeptide domain or genetic polymorphism.
Sex Chromosome Alterations Associate with Tumor Progression in Sporadic Colorectal Carcinomas
Authors: Bottarelli Lorena , Azzoni Cinzia , Necchi Francesca , Lagrasta Costanza , Tamburini Elisa , D'Adda Tiziana , Pizzi Silvia , Sarli Leopoldo , Rindi Guido , Bordi Cesare
Published: August 2007

Purpose: The X and Y chromosomes have been associated with malignancy in different types of human tumors. This study attempts to determine the involvement of X chromosome and pseudoautosomal regions (PAR) in sporadic colorectal carcinogenesis.

Experimental Design: An allelotyping of X chromosome in 20 premalignant and 22 malignant sporadic colorectal tumors (CRC) from female patients and an analysis of losses [loss of heterozygosity (LOH)] on PARs from 44 CRCs and 12 adenomas of male patients were carried out. In male tumors, a fluorescence in situ hybridization analysis was done to identify which sex chromosome was possibly lost.

Results: The LOH frequency in female CRCs was 46% with higher incidence in patients with tumor recurrence than in those who were disease-free (P < 0.01) and with a significant difference from adenomas (11%; P < 0.0001). The LOH rate of PARs in male CRCs was 37% with a frequency significantly higher in patients with recurrence (P < 0.03). These results were maintained also when data from PARs of all 66 male and female patients were cumulated (P < 0.05). LOH in PARs was significantly correlated with LOH at 5q (P < 0.01) and 18q (P < 0.01), early and late events, respectively, in colorectal carcinogenesis. Fluorescence in situ hybridization analysis in male patients with extensive PAR LOH revealed a preferential loss of the Y chromosome.

Conclusions: Our data suggest a role for sex chromosome deletions in the malignant progression of sporadic CRCs and support the presence in the PARs of putative tumor suppressor genes involved in the progression of human sporadic CRCs.
Synergistic In vivo Antitumor Effect of the Histone Deacetylase Inhibitor MS-275 in Combination with Interleukin 2 in a Murine Model of Renal Cell Carcinoma
Authors: Kato Yukihiko , Yoshimura Kiyoshi , Shin Tahiro , Verheul Henk , Hammers Hans , Sanni Tolib B. , Salumbides Brenda C. , Van Erp Karen , Schulick Richard , Pili Roberto
Published: August 2007

Purpose: High-dose interleukin 2 (IL-2) is a Food and Drug Administration–approved regimen for patients with metastatic renal cell carcinoma. However, the toxicity and limited clinical benefit associated with IL-2 has hampered its use. Histone deacetylase (HDAC) inhibitors have been shown to have antitumor activity in different tumor models including renal cell carcinoma, and to have immunomodulatory properties. In our study, we tested the effectiveness of combination therapy of IL-2 with the HDAC inhibitor MS-275 in a murine renal cell carcinoma (RENCA) model.

Experimental Design: RENCA luciferase–expressing cells were implanted in the left kidney of BALB/C mice. Animals were randomly divided into four groups and treated with either vehicle, 150,000 IU of IL-2 twice daily by i.p. injections (twice weekly), 5 mg/kg of MS-275 daily by oral gavage (5 d/wk), or its combination. Treatment was started either 3 or 9 days following tumor cell injection.

Results: Weekly luciferase images and tumor weight after 2 weeks of treatment showed significant tumor inhibition (>80%) in the combination treatment as compared with the IL-2 (no significant inhibition) or MS-275 (∼40% inhibition) treatment groups. Spontaneous lung metastases were also inhibited in the combination treatment (>90% inhibition) as compared with the single treatment group. Kaplan-Meier analyses showed statistically significant increased survival in the combination group as compared with controls and single agents. Splenocytes from mice treated with combination treatment showed greater lysis of RENCA cells than splenocytes from mice treated with single agents. The percentage of CD4+CD25+ T cells and Foxp3+ T cells (T regulatory cells) was increased or reduced, respectively, in lymph nodes from tumor-bearing animals treated with the combination of MS-275 and IL-2 as compared with control and single agents. Depletion of CD8+ T cells abrogated the survival benefit from MS-275 + IL-2 combination.

Conclusions: These results show that the combination of IL-2 and MS-275 has a synergistic antitumor effect in vivo in an immunocompetent murine model of renal cell carcinoma. The antitumor effect was associated with the decreased number of T regulatory cells and the increased antitumor cytotoxicity by splenocytes. In conclusion, these preclinical data provide the rationale for clinical testing of the combination of IL-2 and HDAC inhibitors in the treatment of patients with renal cell carcinoma.
The Role of the DNA Damage Checkpoint Pathway in Intraductal Papillary Mucinous Neoplasms of the Pancreas
Authors: Miyasaka Yoshihiro , Nagai Eishi , Yamaguchi Hiroshi , Fujii Kei , Inoue Takahiro , Ohuchida Kenoki , Yamada Tomomi , Mizumoto Kazuhiro , Tanaka Masao , Tsuneyoshi Masazumi
Published: August 2007

Purpose: Intraductal papillary mucinous neoplasms (IPMN) are known to show a transition from adenoma to carcinoma accompanied by several molecular abnormalities. ATM-Chk2-p53 DNA damage checkpoint activation, which is involved in prevention of the progression of several tumors, was analyzed to evaluate the role of the DNA damage checkpoint in the progression of IPMNs.

Experimental Design: One hundred and twenty-eight IPMNs were classified into four groups (intraductal papillary mucinous adenoma, borderline IPMN, noninvasive intraductal papillary mucinous carcinoma, and invasive intraductal papillary mucinous carcinoma) and stained immunohistochemically using antibody for Thr68-phosphorylated Chk2. Expression of ATM, Chk2, and p21WAF1 and accumulation of p53 were also analyzed.

Results: Chk2 phosphorylation was shown in all adenomas and showed a significant decreasing trend with the progression of atypia (P < 0.0001 by the Cochran-Armitage test for trend). Expression of p21WAF1 also exhibited a decreasing tendency (P < 0.0001), reflecting DNA damage checkpoint inactivation. p53 accumulation was mostly detected in malignant IPMNs. It was suggested that the DNA damage checkpoint provides a selective pressure for p53 mutation.

Conclusion: Our findings indicate that DNA damage checkpoint activation occurs in the early stage of IPMNs and prevents their progression. It is suggested that disturbance of the DNA damage checkpoint pathway due to Chk2 inactivation or p53 mutation contributes to the carcinogenesis of IPMNs.
Molecular Pathways for Cancer Angioprevention
Authors: Albini Adriana , Noonan Douglas M. , Ferrari Nicoletta
Published: August 2007

By analogy to the success of cardiovascular medicine in reducing mortality through preventive measures, cancer chemoprevention has the potential to significantly reduce incidence and mortality due to tumors. Angiogenesis is an event inhibited by most of the promising cancer chemoprevention compounds, a concept we termed “angioprevention.” Here, we review the signaling pathways that are targeted by diverse angioprevention compounds in endothelial cells. We highlight diverse mechanisms of action, implying that combination angioprevention approaches could further improve efficacy and be transferred to clinical practice.
Emmprin and Survivin Predict Response and Survival following Cisplatin-Containing Chemotherapy in Patients with Advanced Bladder Cancer
Authors: Als Anne B. , Dyrskjøt Lars , von der Maase Hans , Koed Karen , Mansilla Francisco , Toldbod Helle E. , Jensen Jens L. , Ulhøi Benedicte P. , Sengeløv Lisa , Jensen Klaus M.E. , Ørntoft Torben F.
Published: August 2007

Purpose: Cisplatin-containing chemotherapy is the standard of care for patients with locally advanced and metastatic transitional cell carcinoma of the urothelium. The response rate is ∼50% and tumor-derived molecular prognostic markers are desirable for improved estimation of response and survival.

Experimental Design: Affymetrix GeneChip expression profiling was carried out using tumor material from 30 patients. A set of genes with an expression highly correlated to survival time after chemotherapy was identified. Two genes were selected for validation by immunohistochemistry in an independent material of 124 patients receiving cisplatin-containing therapy.

Results: Fifty-five differentially expressed genes correlated significantly to survival time. Two of the protein products (emmprin and survivin) were validated using immunohistochemistry. Multivariate analysis identified emmprin expression (hazard ratio, 2.23; P < 0.0001) and survivin expression (hazard ratio, 2.46; P < 0.0001) as independent prognostic markers for poor outcome, together with the presence of visceral metastases (hazard ratio, 2.62; P < 0.0001). In the clinical good prognostic group of patients without visceral metastases, both markers showed significant discriminating power as supplemental risk factors (P < 0.0001). Within this group of patients, the subgroups of patients with no positive, one positive, or two positive immunohistochemistry scores (emmprin and survivin) had estimated 5-year survival rates of 44.0%, 21.1%, and 0%, respectively. Response to chemotherapy could also be predicted with an odds ratio of 4.41 (95% confidence interval, 1.91-10.1) and 2.48 (95% confidence interval, 1.1-5.5) for emmprin and survivin, respectively.

Conclusions: Emmprin and survivin proteins were identified as strong independent prognostic factors for response and survival after cisplatin-containing chemotherapy in patients with advanced bladder cancer.
Highly Efficient Gene Delivery for Bladder Cancers by Intravesically Administered Replication-Competent Retroviral Vectors
Authors: Kikuchi Eiji , Menendez Silvia , Ozu Choichiro , Ohori Makoto , Cordon-Cardo Carlos , Logg Christopher R. , Kasahara Noriyuki , Bochner Bernard H.
Published: August 2007

Purpose: In an attempt to improve viral delivery of potentially therapeutic genes via an intravesical route, we have recently developed murine leukemia virus-based replication-competent retrovirus (RCR) vectors.

Experimental Design: We evaluated the transduction efficiency of intravesically administered RCR vectors to bladder tumor using orthotopic animal models to determine their potential as delivery vectors for bladder cancer.

Results: The RCR vector containing green fluorescent protein (GFP) marker gene achieved efficient in vitro transmission of the GFP transgene. Murine bladder tumor-2 mouse bladder tumors exposed to intravesically administered RCR vectors exhibited 0%, 9.2 ± 2.9%, and 30.0 ± 6.2% of GFP expression at 9, 18, and 27 days after exposure in the orthotopic model, respectively. Orthotopic KU-19-19 human bladder tumors exposed to intravesically administered RCR vectors exhibited 3%, 85 ± 1.0%, and 100% of GFP expression at 7, 21, and 35 days after exposure, respectively. GFP staining was observed only in the tumor cells in the bladder. No detectable PCR products of GFP gene could be observed in distant organs. Treatment with RCR vectors containing yeast cytosine deaminase (CD) gene plus 5-fluorocytosine (5-FC) dramatically inhibited the growth of preestablished murine bladder tumor-2 tumors. A single course of 5-FC treatment resulted in a 50% animal survival in mice exposed to RCR-CD compared with a 0% survival in all controls over a 70-day follow-up period.

Conclusions: Intravesically administered RCR vectors can efficiently deliver genes to orthotopic bladder tumor without viral spread in distant organs. RCR-CD/5-FC suicide gene therapy promises to be a novel and potentially therapeutic modality for bladder cancer.
Antagonism of Platelet-Derived Growth Factor Receptor in Non–Small Cell Lung Cancer: Rationale and Investigations
Authors: Bauman Julie E. , Eaton Keith D. , Martins Renato G.
Published: August 2007

Molecules that target growth and survival pathways in cancer cells have revolutionized the treatment of cancer. Imatinib mesylate is one such agent inhibiting the tyrosine kinase that results from the Bcr-Abl translocation. Imatinib is also a potent inhibitor of the platelet-derived growth factor receptor. The platelet-derived growth factor receptor is crucial in the regulation of interstitial fluid pressure, as well as in the function of pericytes. Increased interstitial fluid pressure is a common feature of solid tumors and is thought to impede transcapillary transport of chemotherapy. Preclinical data show that platelet-derived growth factor receptor antagonism decreases interstitial fluid pressure, augments intratumoral concentration of chemotherapy, and impairs tumor growth. Pericytes are important cells in the vascular support structure of tumors regulating endothelial cell survival and directing capillary growth. Preclinical data suggest that dual targeting of pericytes and endothelial cells is a more effective antiangiogenic strategy than antiendothelial monotherapy. Two phase II studies in advanced non–small cell lung cancer are currently under way with imatinib. The first trial evaluates the use of intermittent imatinib and weekly paclitaxel in elderly patients. The second trial evaluates a novel maintenance strategy of imatinib and the antivascular endothelial growth factor antibody bevacizumab after first-line chemotherapy with bevacizumab. These trials should indicate whether encouraging preclinical data can be translated into clinical benefit in non–small cell lung cancer.
A Novel FLT3 Inhibitor FI-700 Selectively Suppresses the Growth of Leukemia Cells with FLT3 Mutations
Authors: Kiyoi Hitoshi , Shiotsu Yukimasa , Ozeki Kazutaka , Yamaji Satomi , Kosugi Hiroshi , Umehara Hiroshi , Shimizu Makiko , Arai Hitoshi , Ishii Kenichi , Akinaga Shiro , Naoe Tomoki
Published: August 2007

Purpose: The aim of this study was to evaluate the antileukemia activity of a novel FLT3 kinase inhibitor, FI-700.

Experimental Design: The antileukemia activity of FI-700 was evaluated in human leukemia cell lines, mutant or wild-type (Wt)-FLT3–expressing mouse myeloid precursor cell line, 32D and primary acute myeloid leukemia cells, and in xenograft or syngeneic mouse leukemia models.

Results: FI-700 showed a potent IC50 value against FLT3 kinase at 20 nmol/L in an in vitro kinase assay. FI-700 showed selective growth inhibition against mutant FLT3-expressing leukemia cell lines and primary acute myeloid leukemia cells, whereas it did not affect the FLT3 ligand (FL)–driven growth of Wt-FLT3–expressing cells. These antileukemia activities were induced by the significant dephosphorylations of mutant FLT3 and STAT5, which resulted in G1 arrest of the cell cycle. Oral administration of FI-700 induced the regression of tumors in a s.c. tumor xenograft model and increased the survival of mice in an i.v. transplanted model. Furthermore, FI-700 treatment eradicated FLT3/ITD-expressing leukemia cells, both in the peripheral blood and in the bone marrow. In this experiment, the depletion of FLT3/ITD-expressing cells by FI-700 was more significant than that of Ara-C, whereas bone marrow suppression by FI-700 was lower than that by Ara-C.

Conclusions: FI-700 is a novel and potent FLT3 inhibitor with promising antileukemia activity.
Incorporating Bortezomib into the Treatment of Lung Cancer
Authors: Davies Angela M. , Lara Primo N. , Mack Philip C. , Gandara David R.
Published: August 2007

Bortezomib, a small-molecule proteasome inhibitor, has activity in lung cancer both as a single agent and in combination with agents commonly used in lung cancer. The ability of bortezomib to favorably modulate the expression of apoptosis-associated proteins, along with its moderate toxicity as a single agent, provides the basis for its combination with cytotoxic agents in the treatment of lung cancer. In non–small cell lung cancer, bortezomib as a single agent has limited activity but in combination with chemotherapy has shown encouraging activity without significantly adding to toxicity. Bortezomib as a single agent has shown minimal activity in small cell lung cancer. Although the role of bortezomib in lung cancer is uncertain, it is likely to have its greatest clinical benefit when given in combination with other therapeutics. Ongoing studies are focused on optimizing the scheduling of bortezomib with chemotherapy, investigating its combination with targeted agents and radiation, and examining its efficacy in a specific subgroup, bronchioloalveolar carcinoma.
HKI-272 in Non–Small Cell Lung Cancer
Authors: Wong Kwok-Kin
Published: August 2007

Somatic mutations in the kinase domain of the epidermal growth factor receptor (EGFR) gene are found in ∼10% of lung adenocarcinomas sequenced in the United States and in ∼30% sequenced in Asia. These mutations are associated with sensitivity to the EGFR inhibitors gefitinib and erlotinib. Many patients who initially respond to erlotinib or gefitinib subsequently relapse. Studies have identified EGFR T790M mutations in tumors from patients who initially responded and then relapsed. The T790M mutation, when combined in vitro with treatment-sensitizing EGFR mutations, permits the continued growth of tumor cells in the presence of erlotinib and gefitinib. HKI-272 is an irreversible EGFR/HER/ErbB inhibitor that has been shown to inhibit the growth of T790M mutant cells in vitro in human lung cancer cell lines and in murine cells transfected with sensitizing EGFR mutations. A phase I HKI-272 monotherapy trial in patients with solid tumors is close to completion. Preliminary analyses of the trial, presented at the 2006 annual meeting of American Society of Clinical Oncology, showed that HKI-272 can achieve stable disease control for over 6 months in some patients with non–small cell lung cancer that has progressed after treatment with gefitinib or erlotinib. A phase II trial of HKI-272 in non–small cell lung cancer patients has been initiated. HKI-272 might offer benefits to non–small cell lung cancer patients who have relapsed after an initial response to erlotinib.
A Unique Subset of CD4+CD25highFoxp3+ T Cells Secreting Interleukin-10 and Transforming Growth Factor-β1 Mediates Suppression in the Tumor Microenvironment
Authors: Strauss Laura , Bergmann Christoph , Szczepanski Miroslaw , Gooding William , Johnson Jonas T. , Whiteside Theresa L.
Published: August 2007

Purpose: Immunosuppression, including that mediated by CD4+CD25highFoxp3+ regulatory T cells (Treg), is a characteristic feature of head and neck squamous cell carcinoma (HNSCC). Tregs with a distinct phenotype in tumor-infiltrating lymphocytes (TIL) contribute to local immune suppression.

Experimental Design: The frequency and phenotype of Treg in TIL and/or peripheral blood mononuclear cells (PBMC) in 15 HNSCC patients and PBMC in 15 normal controls were compared. Single-cell sorted CD4+CD25high T cells were tested for regulatory function by coculture with carboxyfluorescein diacetate succinimidyl ester–labeled and activated autologous CD4+CD25− responder T cells. Transwell inserts separating Treg from responders and neutralizing interleukin-10 (IL-10) or transforming growth factor-β1 (TGF-β1) antibodies were used to evaluate the mechanisms used by Treg to suppress responder cell proliferation.

Results: In TIL, CD25+ cells were enriched in the CD3+CD4+ subset (13 ± 3%) relative to circulating CD3+CD4+ T cells (3 ± 0.7%) in HNSCC patients (P ≤ 0.01) or normal controls (2 ± 1.5%; P ≤ 0.001). Among the CD3+CD4+ subset, CD25high Treg represented 3 ± 0.5% in TIL, 1 ± 0.3% in PBMC, and 0.4 ± 0.2% in normal controls. Tregs in TIL were GITR+, IL-10+, and TGF-β1+, although circulating Treg up-regulated CD62L and CCR7 but not GITR, IL-10, or TGF-β1. Treg in TIL mediated stronger suppression (P ≤ 0.001) than Treg in PBMC of HNSCC patients. The addition of neutralizing IL-10 and TGF-β antibodies almost completely abrogated suppression (5 ± 2.51%). Transwell inserts partly prevented suppression (60 ± 5% versus 95 ± 5%).

Conclusions: Suppression in the tumor microenvironment is mediated by a unique subset of Treg, which produce IL-10 and TGF-β1 and do not require cell-to-cell contact between Treg and responder cells for inhibition.
Enzastaurin, a Protein Kinase Cβ–Selective Inhibitor, and Its Potential Application as an Anticancer Agent in Lung Cancer
Authors: Herbst Roy S. , Oh Yun , Wagle Asavari , Lahn Michael
Published: August 2007

Enzastaurin, an oral serine/threonine kinase inhibitor, suppresses signaling through protein kinase C (PKC)-β and the phosphatidylinositol 3-kinase/AKT pathway to induce tumor cell apoptosis, reduce proliferation, and suppress tumor-induced angiogenesis. In contrast to previous PKC inhibitors, enzastaurin is very well tolerated with a favorable safety profile, allowing it to be dosed for extended durations. In the present review, we summarize the rationale for targeting PKC in cancer, the preclinical experience of enzastaurin, and the clinical findings of the current phase I and II studies. Based on the combined information, we present the rationale for its future assessment in the treatment of lung cancer.
Is There a Role for Cetuximab in Non–Small Cell Lung Cancer?
Authors: Morgensztern Daniel , Govindan Ramaswamy
Published: August 2007

The epidermal growth factor receptor (EGFR) is commonly overexpressed in non–small cell lung cancer (NSCLC). In addition, activating mutations in the EGFR tyrosine kinase domain have been described almost exclusively in NSCLC. Cetuximab, a monoclonal antibody against EGFR, has only modest single-agent activity in advanced NSCLC. A few phase II studies conducted in advanced NSCLC show no significant benefit from adding cetuximab to chemotherapy. However, in vitro observations of synergy between EGFR inhibitors and radiation therapy have been confirmed in the clinical setting of head and neck cancer. The addition of cetuximab to radiotherapy improves survival in patients with locally advanced unresectable squamous cell cancer of the head and neck compared with radiotherapy alone and this combination is being actively studied in locally advanced NSCLC. Research is also ongoing to define the role of cetuximab in combination with other targeted agents. This review will summarize the results of recently published studies on cetuximab and outline current research with this agent in NSCLC.
Repeated Intermittent Low-Dose Therapy with Zoledronic Acid Induces an Early, Sustained, and Long-Lasting Decrease of Peripheral Vascular Endothelial Growth Factor Levels in Cancer Patients
Authors: Santini Daniele , Vincenzi Bruno , Galluzzo Sara , Battistoni Fabrizio , Rocci Laura , Venditti Olga , Schiavon Gaia , Angeletti Silvia , Uzzalli Federica , Caraglia Michele , Dicuonzo Giordano , Tonini Giuseppe
Published: August 2007

Purpose: On the basis of stimulating data on animals reporting that weekly regimens of zoledronic acid (ZA) were effective in reducing skeletal tumor burden, we designed a study on humans to investigate the potential antiangiogenic role of a weekly low-dose therapy with ZA in patients with malignancies.

Experimental Design: Twenty-six consecutive patients with advanced solid cancer and bone metastases received 1 mg of ZA every week for four times (days 1, 7, 14, and 21) followed by 4 mg of ZA with a standard 28-day schedule repeated thrice (days 28, 56, and 84). Patients were prospectively evaluated for circulating levels of vascular endothelial growth factor (VEGF) just before the beginning of drug infusion (0) and again at 7, 14, 21, 28, 56, and 84 days after the first ZA infusion.

Results: The median VEGF basal value showed an early statistically significant (P = 0.038) decrease 7 days after the first 1-mg infusion of ZA. This effect on VEGF-circulating levels persisted also after the following 1-mg infusions at 14 (P = 0.002), 21 (P = 0.001), and 28 days (P = 0.008). Interestingly, the decrease of VEGF-circulating levels persisted also at each programmed time point during the second phase of the study (ZA 4 mg every 4 weeks). No significant differences were recorded in platelet levels, WBC count, or hemoglobin concentration before and after each ZA infusion.

Conclusions: In the present study, we report that a repeated low-dose therapy with ZA is able to induce an early significant and long-lasting decrease of VEGF levels in cancer patients.