bluuebunny/crossref_metadata_2025 huggingface dataset:
Autophagy Is Activated by TGF-β and Potentiates TGF-β–Mediated Growth Inhibition in Human Hepatocellular Carcinoma Cells
Authors: Kiyono Kunihiko , Suzuki Hiroshi I. , Matsuyama Hironori , Morishita Yasuyuki , Komuro Akiyoshi , Kano Mitsunobu R. , Sugimoto Koichi , Miyazono Kohei
Published: November 2009

Transforming growth factor-β (TGF-β) is a multifunctional cytokine that regulates cell growth, differentiation, and apoptosis of various types of cells. Autophagy is emerging as a critical response of normal and cancer cells to environmental changes, but the relationship between TGF-β signaling and autophagy has been poorly understood. Here, we showed that TGF-β activates autophagy in human hepatocellular carcinoma cell lines. TGF-β induced accumulation of autophagosomes and conversion of microtubule-associated protein 1 light chain 3 and enhanced the degradation rate of long-lived proteins. TGF-β increased the mRNA expression levels of BECLIN1, ATG5, ATG7, and death-associated protein kinase (DAPK). Knockdown of Smad2/3, Smad4, or DAPK, or inhibition of c-Jun NH2-terminal kinase, attenuated TGF-β–induced autophagy, indicating the involvement of both Smad and non-Smad pathway(s). TGF-β activated autophagy earlier than execution of apoptosis (6-12 versus 48 h), and reduction of autophagy genes by small interfering RNA attenuated TGF-β–mediated growth inhibition and induction of proapoptotic genes Bim and Bmf, suggesting the contribution of autophagy pathway to the growth-inhibitory effect of TGF-β. Additionally, TGF-β also induced autophagy in some mammary carcinoma cells, including MDA-MB-231 cells. These findings show that TGF-β signaling pathway activates autophagy in certain human cancer cells and that induction of autophagy is a novel aspect of biological functions of TGF-β. [Cancer Res 2009;69(23):8844–52]
Dynamic Gene Expression Analysis Links Melanocyte Growth Arrest with Nevogenesis
Authors: Yang Guang , Thieu Khanh , Tsai Kenneth Y. , Piris Adriano , Udayakumar Durga , Njauw Ching-Ni Jenny , Ramoni Marco F. , Tsao Hensin
Published: November 2009

Like all primary cells in vitro, normal human melanocytes exhibit a physiologic decay in proliferative potential as it transitions to a growth-arrested state. The underlying transcriptional program(s) that regulate this phenotypic change is largely unknown. To identify molecular determinants of this process, we performed a Bayesian-based dynamic gene expression analysis on primary melanocytes undergoing proliferative arrest. This analysis revealed several related clusters whose expression behavior correlated with the melanocyte growth kinetics; we designated these clusters the melanocyte growth arrest program (MGAP). These MGAP genes were preferentially represented in benign melanocytic nevi over melanomas and selectively mapped to the hepatocyte fibrosis pathway. This transcriptional relationship between melanocyte growth stasis, nevus biology, and fibrogenic signaling was further validated in vivo by the demonstration of strong pericellular collagen deposition within benign nevi but not melanomas. Taken together, our study provides a novel view of fibroplasia in both melanocyte biology and nevogenesis. [Cancer Res 2009;69(23):9029–37]
De-N-acetyl GM3 Promotes Melanoma Cell Migration and Invasion through Urokinase Plasminogen Activator Receptor Signaling–Dependent MMP-2 Activation
Authors: Liu Ji-Wei , Sun Ping , Yan Qiu , Paller Amy S. , Gerami Pedram , Ho Nancy , Vashi Neelam , Le Poole I. Caroline , Wang Xiao-qi
Published: November 2009

We have recently discovered that de-N-acetyl GM3 [NeuNH2LacCer, d-GM3], a derivative of ganglioside GM3, is specifically expressed in metastatic tumor cells and that its expression correlates with an enhanced metastatic phenotype. Although the classic N-acetylated form of GM3 (NeuAcLacCer, c-GM3) is found in both normal and tumor cells, metastatic tumor cells (but not other cells) predominantly express d-GM3 (82–95% of total GM3). d-GM3 expression is mainly found in metastatic melanomas, but not in benign nevi or the majority of primary melanomas. Using metastatic (d-GM3–positive) and poorly invasive (d-GM3–negative) human melanoma cell lines, we found that d-GM3 stimulates cell migration and invasion by increasing the expression and activation of urokinase-like plasminogen activator (uPA). Further studies showed that d-GM3 activates matrix metalloproteinase-2 (MMP-2), but not MMP-9, when uPA receptor signaling is activated. These results implicate d-GM3 as a specific marker for metastatic melanoma and a novel therapeutic target for neoplastic diseases. [Cancer Res 2009;69(22):8662–9]
Targeted Disruption of theS1P2Sphingosine 1-Phosphate Receptor Gene Leads to Diffuse Large B-Cell Lymphoma Formation
Authors: Cattoretti Giorgio , Mandelbaum Jonathan , Lee Nancy , Chaves Alicia H. , Mahler Ashley M. , Chadburn Amy , Dalla-Favera Riccardo , Pasqualucci Laura , MacLennan A. John
Published: November 2009

S1P2 sphingosine 1-phosphate receptor signaling can regulate proliferation, survival, morphology, and migration in many cell types in vitro. Here, we report that S1P2−/− mice develop clonal B-cell lymphomas with age, such that approximately half of the animals display this neoplasm by 1.5 to 2 years of age. Histologic, immunophenotypic, and molecular analyses revealed a uniform tumor phenotype with features of germinal center (GC)–derived diffuse large B-cell lymphoma (DLBCL). Tumor formation was preceded by increases in GC B cells and CD69+ T cells, as well as an increased formation of spontaneous GCs, suggesting that S1P2 loss may promote lymphomagenesis in part by disrupting GC B-cells homeostasis. With the sole exception of rare lung tumors, the effect of S1P2 gene disruption is remarkably restricted to DLBCL. In humans, 28 of 106 (26%) DLBCL samples were found to harbor multiple somatic mutations in the 5′ sequences of the S1P2 gene. Mutations displayed features resembling those generated by the IgV-associated somatic hypermutation mechanism, but were not detected at significant levels in normal GC B cells, indicating a tumor-associated aberrant function. Collectively, our data suggest that S1P2 signaling may play a critical role in suppressing DLBCL formation in vivo. The high incidence of DLBCL in S1P2−/− mice, its onset at old age, and the relative lack of other neoplasms identify these mice as a novel, and potentially valuable, model for this highly prevalent and aggressive human malignancy. [Cancer Res 2009;69(22):8686–92]
Persistence of Betapapillomavirus Infections as a Risk Factor for Actinic Keratoses, Precursor to Cutaneous Squamous Cell Carcinoma
Authors: Plasmeijer Elsemieke I. , Neale Rachel E. , de Koning Maurits N.C. , Quint Wim G.V. , McBride Penelope , Feltkamp Mariet C.W. , Green Adele C.
Published: November 2009

Human papillomaviruses from the β genus (βPV) are a possible cause of cutaneous squamous cell carcinoma (SCC). We assessed the extent to which βPV infections persisted long-term in a subtropical Australian community and whether βPV persistence is positively associated with actinic keratoses, precursor for SCC. Eyebrow hairs were collected from 171 participants of the community-based Nambour Skin Cancer Study in 1996 and 2003. Hair samples were tested for the presence of DNA from 25 different βPV types and assessed in relation to actinic keratosis presence in 2007. In 1996, a total of 413 βPV infections were found in 73% of participants, increasing to 490 infections among 85% in 2003. Of the total βPV infections detected, 211 (30%) were found to persist. Age was significantly associated with βPV persistence: those ages >60 years had 1.5-fold (95% confidence interval, 1.1-1.9) increased risk of type-specific viral persistence than those ages <40 years. After accounting for actinic keratoses at baseline, persistence of βPV DNA resulted in a 1.4-fold (95% confidence interval, 1.0-1.9) increase in risk of having actinic keratoses on the face in 2007. In conclusion, persistent βPV infections in this population were associated with an increased occurrence of actinic keratosis. Additional studies are needed to determine the possible association of βPV persistence with SCC. [Cancer Res 2009;69(23):8926–31]
Calcineurin Inhibitors Activate the Proto-Oncogene Ras and Promote Protumorigenic Signals in Renal Cancer Cells
Authors: Datta Dipak , Contreras Alan G. , Basu Aninda , Dormond Olivier , Flynn Evelyn , Briscoe David M. , Pal Soumitro
Published: November 2009

The development of cancer is a major problem in immunosuppressed patients, particularly after solid organ transplantation. We have recently shown that calcineurin inhibitors (CNI) used to treat transplant patients may play a critical role in the rapid progression of renal cancer. To examine the intracellular signaling events for CNI-mediated direct tumorigenic pathway(s), we studied the effect of CNI on the activation of proto-oncogenic Ras in human normal renal epithelial cells (REC) and renal cancer cells (786-0 and Caki-1). We found that CNI treatment significantly increased the level of activated GTP-bound form of Ras in these cells. In addition, CNI induced the association of Ras with one of its effector molecules, Raf, but not with Rho and phosphatidylinositol 3-kinase; CNI treatment also promoted the phosphorylation of the Raf kinase inhibitory protein and the downregulation of carabin, all of which may lead to the activation of the Ras-Raf pathway. Blockade of this pathway through either pharmacologic inhibitors or gene-specific small interfering RNA significantly inhibited CNI-mediated augmented proliferation of renal cancer cells. Finally, it was observed that CNI treatment increased the growth of human renal tumors in vivo, and the Ras-Raf pathway is significantly activated in the tumor tissues of CNI-treated mice. Together, targeting the Ras-Raf pathway may prevent the development/progression of renal cancer in CNI-treated patients. [Cancer Res 2009;69(23):8902–9]
Improved Expression and Reactivity of Transduced Tumor-Specific TCRs in Human Lymphocytes by Specific Silencing of Endogenous TCR
Authors: Okamoto Sachiko , Mineno Junichi , Ikeda Hiroaki , Fujiwara Hiroshi , Yasukawa Masaki , Shiku Hiroshi , Kato Ikunoshin
Published: November 2009

Adoptive T-cell therapy using lymphocytes genetically engineered to express tumor antigen-specific TCRs is an attractive strategy for treating patients with malignancies. However, there are potential drawbacks to this strategy: mispairing of the introduced TCR α/β chains with the endogenous TCR subunits and competition of CD3 molecules between the introduced and endogenous TCRs can impair cell surface expression of the transduced TCR, resulting in insufficient function and potential generation of autoreactive T cells. In addition, the risk of tumor development following the infusion of cells with aberrant vector insertion sites increases with the vector copy number in the transduced cells. In this study, we developed retroviral vectors encoding both small interfering RNA constructs that specifically down-regulate endogenous TCR and a codon-optimized, small interfering RNA–resistant TCR specific for the human tumor antigens MAGE-A4 or WT1. At low copy numbers of the integrated vector, the transduced human lymphocytes exhibited high surface expression of the introduced tumor-specific TCR and reduced expression of endogenous TCRs. In consequence, the vector-transduced lymphocytes showed enhanced cytotoxic activity against antigen-expressing tumor cells. Therefore, our novel TCR gene therapy may open a new gate for effective immunotherapy in cancer patients. [Cancer Res 2009;69(23):9003–11]
Tangeretin Sensitizes Cisplatin-Resistant Human Ovarian Cancer Cells through Downregulation of Phosphoinositide 3-Kinase/Akt Signaling Pathway
Authors: Arafa El-Shaimaa A. , Zhu Qianzheng , Barakat Bassant M. , Wani Gulzar , Zhao Qun , El-Mahdy Mohamed A. , Wani Altaf A.
Published: November 2009

Combination of innocuous dietary components with anticancer drugs is an emerging new strategy for cancer chemotherapy to increase antitumor responses. Tangeretin is a citrus flavonoid known to inhibit cancer cell proliferation. Here, we show an enhanced response of A2780/CP70 and 2008/C13 cisplatin-resistant human ovarian cancer cells to various combination treatments of cisplatin and tangeretin. Pretreatment of cells with tangeretin before cisplatin treatment synergistically inhibited cancer cell proliferation. This combination was effective in activating apoptosis via caspase cascade as well as arresting cell cycle at G2-M phase. Moreover, phospho-Akt and its downstream substrates, e.g., NF-κB, phospho-GSK-3β, and phospho-BAD, were downregulated upon tangeretin-cisplatin treatment. The tangeretin-cisplatin–induced apoptosis in A2780/CP70 cells was increased by phosphoinositide-3 kinase (PI3K) inhibition and siRNA-mediated Akt silencing, but reduced by overexpression of constitutively activated Akt and GSK-3β inhibition. The overall results indicated that tangeretin exposure preconditions cisplatin-resistant human ovarian cancer cells for a conventional response to low-dose cisplatin-induced cell death occurring through downregulation of PI3K/Akt signaling pathway. Thus, effectiveness of tangeretin combinations, as a promising modality in the treatment of resistant cancers, warrants systematic clinical studies. [Cancer Res 2009;69(23):8910–7]
De novo Discovery of a γ-Secretase Inhibitor Response Signature Using a Novel In vivo Breast Tumor Model
Authors: Watters James W. , Cheng Chun , Majumder Pradip K. , Wang Ruojie , Yalavarthi Sireesha , Meeske Carol , Kong Lingxin , Sun Wenping , Lin Jie , Heyer Joerg , Ware Chris , Winter Christopher , Reilly John F. , Demuth Tim , Clark Steve , Chiu M. Isabel , Robinson Murray O. , Kohl Nancy , Kannan Karuppiah
Published: November 2009

Notch pathway signaling plays a fundamental role in normal biological processes and is frequently deregulated in many cancers. Although several hypotheses regarding cancer subpopulations most likely to respond to therapies targeting the Notch pathway have been proposed, clinical utility of these predictive markers has not been shown. To understand the molecular basis of γ-secretase inhibitor (GSI) sensitivity in breast cancer, we undertook an unbiased, de novo responder identification study using a novel genetically engineered in vivo breast cancer model. We show that tumors arising from this model are heterogeneous on the levels of gene expression, histopathology, growth rate, expression of Notch pathway markers, and response to GSI treatment. In addition, GSI treatment of this model was associated with inhibition of Hes1 and proliferation markers, indicating that GSI treatment inhibits Notch signaling. We then identified a pretreatment gene expression signature comprising 768 genes that is significantly associated with in vivo GSI efficacy across 99 tumor lines. Pathway analysis showed that the GSI responder signature is enriched for Notch pathway components and inflammation/immune-related genes. These data show the power of this novel in vivo model system for the discovery of biomarkers predictive of response to targeted therapies, and provide a basis for the identification of human breast cancers most likely to be sensitive to GSI treatment. [Cancer Res 2009;69(23):8949–57]
The Fibroblast Growth Factor Receptor Inhibitor PD173074 Blocks Small Cell Lung Cancer Growth In vitro and In vivo
Authors: Pardo Olivier E. , Latigo John , Jeffery Rosemary E. , Nye Emma , Poulsom Richard , Spencer-Dene Bradley , Lemoine Nick R. , Stamp Gordon W. , Aboagye Eric O. , Seckl Michael J.
Published: November 2009

Lung cancer is the commonest cancer killer. Small cell lung cancer (SCLC) is initially chemosensitive, but rapidly relapses in a chemoresistant form with an overall survival of <5%. Consequently, novel therapies are urgently required and will likely arise from an improved understanding of the disease biology. Our previous work showed that fibroblast growth factor-2 induces proliferation and chemoresistance in SCLC cells. Here, we show that the selective fibroblast growth factor receptor (FGFR) inhibitor PD173074 blocks H-510 and H-69 SCLC proliferation and clonogenic growth in a dose-dependent fashion and prevents FGF-2–induced chemoresistance. These effects correlate with the inhibition of both FGFR1 and FGFR2 transphosphorylation. We then determined the efficacy of daily oral administration of PD173074 for 28 days in two human SCLC models. In the H-510 xenograft, tumor growth was impaired similar to that seen with single-agent cisplatin administration, increasing median survival compared with control sham–treated animals. Crucially, the effect of cisplatin was significantly potentiated by coadministration of PD173074. More dramatically, in H-69 xenografts, PD173074 induced complete responses lasting >6 months in 50% of mice. These effects were not a consequence of disrupted tumor vasculature but instead correlated with increased apoptosis (caspase 3 and cytokeratin 18 cleavage) in excised tumors. Moreover, in vivo imaging with 3′-deoxy-3′-[18F]fluorothymidine–positron emission tomography ([18F]FLT-PET) showed decreased intratumoral proliferation in live animals treated with the compound at 7 to 14 days. Our results suggest that clinical trials of FGFR inhibitors should be undertaken in patients with SCLC and that [18F]FLT-PET imaging could provide early in vivo evidence of response. [Cancer Res 2009;69(22):8645–51]
Detection of Treatment-Induced Changes in Signaling Pathways in Gastrointestinal Stromal Tumors Using Transcriptomic Data
Authors: Ochs Michael F. , Rink Lori , Tarn Chi , Mburu Sarah , Taguchi Takahiro , Eisenberg Burton , Godwin Andrew K.
Published: November 2009

Cell signaling plays a central role in the etiology of cancer. Numerous therapeutics in use or under development target signaling proteins; however, off-target effects often limit assignment of positive clinical response to the intended target. As direct measurements of signaling protein activity are not generally feasible during treatment, there is a need for more powerful methods to determine if therapeutics inhibit their targets and when off-target effects occur. We have used the Bayesian Decomposition algorithm and data on transcriptional regulation to create a novel methodology, Differential Expression for Signaling Determination (DESIDE), for inferring signaling activity from microarray measurements. We applied DESIDE to deduce signaling activity in gastrointestinal stromal tumor cell lines treated with the targeted therapeutic imatinib mesylate (Gleevec). We detected the expected reduced activity in the KIT pathway, as well as unexpected changes in the p53 pathway. Pursuing these findings, we have determined that imatinib-induced DNA damage is responsible for the increased activity of p53, identifying a novel off-target activity for this drug. We then used DESIDE on data from resected, post-imatinib treatment tumor samples and identified a pattern in these tumors similar to that at late time points in the cell lines, and this pattern correlated with initial clinical response. The pattern showed increased activity of ETS domain-containing protein Elk-1 and signal transducers and activators of transcription 3 transcription factors, which are associated with the growth of side population cells. DESIDE infers the global reprogramming of signaling networks during treatment, permitting treatment modification that leverages ongoing drug development efforts, which is crucial for personalized medicine. [Cancer Res 2009;69(23):9125–32]
Loss of Collapsin Response Mediator Protein1, as Detected by iTRAQ Analysis, Promotes Invasion of Human Gliomas Expressing Mutant EGFRvIII
Authors: Mukherjee Joydeep , DeSouza Leroi V. , Micallef Johann , Karim Zia , Croul Sid , Siu K.W. Michael , Guha Abhijit
Published: November 2009

Glioblastoma multiforme (GBM) is the most common and lethal primary human brain tumor. GBMs are characterized by a variety of genetic alterations, among which oncogenic mutations of epidermal growth factor receptor (EGFRvIII) is most common. GBMs harboring EGFRvIII have increased proliferation and invasive characteristics versus those expressing wild-type (wt) EGFR. To identify the molecular basis of this increased tumorgenic phenotype, we used iTRAQ-labeling differential proteomic analysis. Among several differentially expressed proteins, we selected CRMP1, a protein implicated in cellular invasion that was markedly decreased in GBMs expressing EGFRvIII, for further study. The differential expression of CRMP1 was confirmed in a panel of human GBM cell lines and operative specimens that express wtEGFR or mutant EGFRvIII by quantitative real-time PCR, Western blot, and immunohistochemical analysis. In human GBM samples, decreased expression of CRMP1 correlated with EGFRvIII positivity. Knockdown of CRMP1 by siRNA resulted in increased invasion of wtEGFR expressing human GBM cells (U87 and U373) to those found in isogenic GBM cells. Exogenous expression of EGFRvIII in these wtEGFR-expressing GBM cells promoted their ability to invade and was accompanied by decreased expression of CRMP1. Rescuing CRMP1 expression decreased invasion of the EGFRvIII-expressing GBM cells by tilting the balance between Rac and Rho. Collectively, these results show that the loss of CRMP1 contribute to the increased invasive phenotype of human GBMs expressing mutant EGFRvIII. [Cancer Res 2009;69(22):8545–54]
Astrocyte Elevated Gene-1: Far More Than Just a Gene Regulated in Astrocytes
Authors: Sarkar Devanand , Emdad Luni , Lee Seok-Geun , Yoo Byoung Kwon , Su Zao-zhong , Fisher Paul B.
Published: November 2009

Since its original cloning by subtraction hybridization in 2002, it is now evident that Astrocyte elevated gene-1 (AEG-1) is a key contributor to the carcinogenic process in diverse organs. AEG-1 protein expression is elevated in advanced stages of many cancers, which correlates with poor survival. In specific cancers, such as breast and liver cancer, the AEG-1 gene itself is amplified, further supporting a seminal role in tumorigenesis. Overexpression and inhibition studies both in in vitro and in in vivo models reveal the importance of AEG-1 in regulating multiple physiologically and pathologically relevant processes including proliferation, invasion, metastasis, and gene expression. AEG-1 is a single-pass transmembrane protein with multiple nuclear localization signals and no known domains or motifs. Although pertinent roles of AEG-1 in the carcinogenic process are established, its potential function (promotion of metastasis only versus functioning as a bona fide oncogene) as well as localization (cell surface versus nucleus) remain areas requiring further clarification. The present review critically evaluates what is currently known about AEG-1 and provides new perspectives relative to this intriguing molecule that may provide a rational target for intervening in the cancer phenotype. [Cancer Res 2009;69(22):8529–35]
Differential Enhancement of Breast Cancer Cell Motility and Metastasis by Helical and Kinase Domain Mutations of Class IA Phosphoinositide 3-Kinase
Authors: Pang Huan , Flinn Rory , Patsialou Antonia , Wyckoff Jeffrey , Roussos Evanthia T. , Wu Haiyan , Pozzuto Maria , Goswami Sumanta , Condeelis John S. , Bresnick Anne R. , Segall Jeffrey E. , Backer Jonathan M.
Published: November 2009

Class IA (p85/p110) phosphoinositide 3-kinases play a major role in regulating cell growth, survival, and motility. Activating mutations in the p110α isoform of the class IA catalytic subunit (PIK3CA) are commonly found in human cancers. These mutations lead to increased proliferation and transformation in cultured cells, but their effects on cell motility and tumor metastasis have not been evaluated. We used lentiviral-mediated gene transfer and knockdown to produce stable MDA-MB-231 cells in which the endogenous human p110α is replaced with either wild-type bovine p110α or the two most common activating p110α mutants, the helical domain mutant E545K and the kinase domain mutant H1047R. The phosphoinositide 3-kinase/Akt pathway was hyperactivated in cells expressing physiologic levels of helical or kinase domain mutants. Cells expressing either mutant showed increased motility in vitro, but only cells expressing the helical domain mutant showed increased directionality in a chemotaxis assay. In severe combined immunodeficient mice, xenograft tumors expressing either mutant showed increased rates of tumor growth compared with tumors expressing wild-type p110α. However, tumors expressing the p110α helical domain mutant showed a marked increase in both tumor cell intravasation into the blood and tumor cell extravasation into the lung after tail vein injection compared with tumors expressing wild-type p110α or the kinase domain mutant. Our observations suggest that, when compared with kinase domain mutations in a genetically identical background, expression of helical domain mutants of p110α produce a more severe metastatic phenotype. [Cancer Res 2009;69(23):8868–76]
Optimized Peptide Vaccines Eliciting Extensive CD8 T-Cell Responses with Therapeutic Antitumor Effects
Authors: Cho Hyun-Il , Celis Esteban
Published: November 2009

A major challenge for developing effective therapeutic vaccines against cancer is overcoming immunologic tolerance to tumor-associated antigens that are expressed on both malignant cells and normal tissues. Herein, we describe a novel vaccination approach, TriVax, that uses synthetic peptides representing CD8 T-cell epitopes, Toll-like receptor agonists that function as potent immunologic adjuvants and costimulatory anti-CD40 antibodies to generate large numbers of high-avidity antigen-reactive T cells capable of recognizing and killing tumor cells. Our results show that TriVax induced huge numbers of long-lasting antigen-specific CD8 T cells that displayed significant antitumor effects in vivo. The administration of a TriVax formulation containing a CD8 T-cell epitope derived from a melanosomal antigen (Trp2180-188) elicited antigen-specific CD8 T cells that induced systemic autoimmunity (vitiligo). More important, TriVax immunization was effective in eliciting potent protective antitumor immunity as well as remarkable therapeutic effects against established B16 melanoma. This therapeutic effect was mediated by CD8 T cells via perforin-mediated lysis and required the participation of type-I IFN but not IFNγ. These results suggest that similar strategies would be applicable for the design of effective vaccination for conducting clinical studies in cancer patients. [Cancer Res 2009;69(23):9012–9]
Breast Cancer Amplified Sequence 2, a Novel Negative Regulator of the p53 Tumor Suppressor
Authors: Kuo Ping-Chang , Tsao Yeou-Ping , Chang Hung-Wei , Chen Po-Han , Huang Chu-Wei , Lin Shinn-Tsuen , Weng Yu-Tzu , Tsai Tzung-Chieh , Shieh Sheau-Yann , Chen Show-Li
Published: November 2009

Breast cancer amplified sequence 2 (BCAS2) was reported previously as a transcriptional coactivator of estrogen receptor. Here, we report that BCAS2 directly interacts with p53 to reduce p53 transcriptional activity by mildly but consistently decreasing p53 protein in the absence of DNA damage. However, in the presence of DNA damage, BCAS2 prominently reduces p53 protein and provides protection against chemotherapeutic agent such as doxorubicin. Deprivation of BCAS2 induces apoptosis in p53 wild-type cells but causes G2-M arrest in p53-null or p53 mutant cells. There are at least two apoptosis mechanisms induced by silencing BCAS2 in wild-type p53-containing cells. Firstly, it increases p53 retention in nucleus that triggers the expression of apoptosis-related genes. Secondly, it increases p53 transcriptional activity by raising p53 phosphorylation at Ser46 and decreases p53 protein degradation by reducing p53 phosphorylation at Ser315. We show for the first time that BCAS2, a small nuclear protein (26 kDa), is a novel negative regulator of p53 and hence a potential molecular target for cancer therapy. [Cancer Res 2009;69(23):8877–85]
Curcumin Potentiates the Antitumor Effects of Bacillus Calmette-Guerin against Bladder Cancer through the Downregulation of NF-κB and Upregulation of TRAIL Receptors
Authors: Kamat Ashish M. , Tharakan Sheeja T. , Sung Bokyung , Aggarwal Bharat B.
Published: November 2009

Although Bacillus Calmette-Guerin (BCG) intravesical therapy is a standard treatment for bladder cancer, eventual failure of response is a major problem. Treatments that can augment BCG therapy are urgently needed. We investigated whether curcumin, a component of Curcuma longa (also called turmeric), has potential to improve the current therapy using in vitro and in vivo MBT-2 murine tumor models. We found that curcumin potentiated BCG-induced apoptosis of human bladder cancer cells. BCG stimulated the release of tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) from peripheral mononuclear neutrophils in a dose- and time-dependent manner, whereas curcumin enhanced the upregulation of TRAIL receptors. Electrophoretic mobility shift assay revealed that curcumin also suppressed the BCG-induced activation of the cell survival transcription factor NF-κB. In a syngeneic bladder cancer model, curcumin alone reduced the bladder tumor volume, but a significantly greater reduction was observed when BCG and curcumin were used in combination (P < 0.0001 versus control; P < 0.003 versus BCG alone). This was accompanied by a significant decrease in the proliferation marker Ki-67 (P < 0.01 versus control; P < 0.01 versus BCG alone) and microvessel density (CD31; P < 0.01 versus control; P < 0.01 versus BCG alone), decreased NF-κB in tumor tissue compared with the control, induced apoptosis, and decreased cyclin D1, vascular endothelial growth factor, cyclooxygenase-2, c-myc, and Bcl-2 expression in the tumor tissue. Upregulation of TRAIL receptor by the combination was also observed in tumor tissues. Overall, our results suggest that curcumin potentiates the antitumor effect of BCG through the inhibition of NF-κB and induction of TRAIL receptors in bladder cancer cells. [Cancer Res 2009;69(23):8958–66]
Estradiol Alters Cell Growth in Nonmalignant Colonocytes and Reduces the Formation of Preneoplastic Lesions in the Colon
Authors: Weige Charles C. , Allred Kimberly F. , Allred Clinton D.
Published: November 2009

Numerous clinical and animal studies show that hormone replacement therapy reduces the risk of colon tumor formation. However, the majority of experiments have shown that estradiol (E2) does not inhibit the growth of malignantly transformed colon epithelia. As such, the presented studies focused on evaluating the effects of E2 in noncancerous colonocytes. E2 treatments (0–10 nmol/L) reduced cell growth and increased apoptotic activity in young adult mouse colonocytes (YAMC), a nonmalignant cell line, in a dose-responsive manner. These effects were lost in the YAMC-Ras cells, an isogenic cell line with a single malignant transformation. Cotreatment with an estrogen receptor (ER) antagonist inhibited the physiologic effects of E2 in YAMC cells, suggesting that the response is ER mediated. To further study the effect of E2 on colonic epithelia, we evaluated the development of preneoplastic lesions in ovariectomized wild-type (WT) and ERβ knockout (ERβKO) mice treated with either vehicle or E2. WT E2-treated animals exhibited significantly fewer aberrant crypt foci and increased apoptotic activity in colonic epithelia when compared with WT control mice or ERβKO animals receiving either treatment. For the first time, we showed that E2 alters the growth of nontransformed colonocytes in vitro and that, through an ERβ-mediated mechanism, E2 influences the physiology of noncancerous colonocytes, resulting in fewer preneoplastic lesions. Collectively, these data show that the protective actions of E2 occur primarily during the initiation/promotion stages of disease development and identify the hormone as an important chemoprotective agent. [Cancer Res 2009;69(23):9118–24]
MiR-15a and MiR-16 Control Bmi-1 Expression in Ovarian Cancer
Authors: Bhattacharya Resham , Nicoloso Milena , Arvizo Rochelle , Wang Enfeng , Cortez Angelica , Rossi Simona , Calin George A. , Mukherjee Priyabrata
Published: November 2009

Oncogenic activation of Bmi-1 is found in a wide variety of epithelial malignancies including ovarian cancer, yet a specific mechanism for overexpression of Bmi-1 has not been determined. Thus, realizing the immense pathologic significance of Bmi-1 in cancer, we wanted to investigate if microRNA (miRNA) aberrations played a role in the regulation of Bmi-1 in ovarian cancer. In this report, we identify two miRNAs, miR-15a and miR-16, that are underexpressed in ovarian cell lines and in primary ovarian tissues. We show that these miRNAs directly target the Bmi-1 3′ untranslated region and significantly correlate with Bmi-1 protein levels in ovarian cancer patients and cell lines. Furthermore, Bmi-1 protein levels are downregulated in response to miR-15a or miR-16 expression and lead to significant reduction in ovarian cancer cell proliferation and clonal growth. These findings suggest the development of therapeutic strategies by restoring miR-15a and miR-16 expression in ovarian cancer and in other cancers that involve upregulation of Bmi-1. [Cancer Res 2009;69(23):9090–5]
Recognition and Killing of Brain Tumor Stem-Like Initiating Cells by CD8+ Cytolytic T Cells
Authors: Brown Christine E. , Starr Renate , Martinez Catalina , Aguilar Brenda , D'Apuzzo Massimo , Todorov Ivan , Shih Chu-Chih , Badie Behnam , Hudecek Michael , Riddell Stanley R. , Jensen Michael C.
Published: November 2009

Solid tumors contain a subset of stem-like cells that are resistant to the cytotoxic effects of chemotherapy/radiotherapy, but their susceptibility to cytolytic T lymphocyte (CTL) effector mechanisms has not been well characterized. Using a panel of early-passage human brain tumor stem/initiating cell (BTSC) lines derived from high-grade gliomas, we show that BTSCs are subject to immunologic recognition and elimination by CD8+ CTLs. Compared with serum-differentiated CD133low tumor cells and established glioma cell lines, BTSCs are equivalent with respect to expression levels of HLA class I and ICAM-1, similar in their ability to trigger degranulation and cytokine synthesis by antigen-specific CTLs, and equally susceptible to perforin-dependent CTL-mediated cytolysis. BTSCs are also competent in the processing and presentation of antigens as evidenced by the killing of these cells by CTL when antigen is endogenously expressed. Moreover, we show that CTLs can eliminate all BTSCs with tumor-initiating activity in an antigen-specific manner in vivo. Current models predict that curative therapies for many cancers will require the elimination of the stem/initiating population, and these studies lay the foundation for developing immunotherapeutic approaches to eradicate this tumor population. [Cancer Res 2009;69(23):8886–93]
Survivin as a Prognostic Marker for Urothelial Carcinoma of the Bladder: A Multicenter External Validation Study
Authors: Shariat Shahrokh F. , Karakiewicz Pierre I. , Godoy Guilherme , Karam Jose A. , Ashfaq Raheela , Fradet Yves , Isbarn Hendrik , Montorsi Francesco , Jeldres Claudio , Bastian Patrick J. , Nielsen Matthew E. , Mller Stefan C. , Sagalowsky Arthur I. , Lotan Yair
Published: November 2009

Purpose: The aim of the current study was to externally validate the value of survivin as a prognostic marker for bladder cancer in a large multi-institutional cohort of patients treated with radical cystectomy.

Methods: The study comprised 726 patients treated with radical cystectomy and bilateral pelvic lymphadenectomy. Survivin staining and scoring were done with automated systems coupled with advanced color detection software. Specimens showing at least 10 reactivity were considered altered. Predictive accuracy was quantified using the concordance index and 200-bootstrap resamples were used to reduce overfit bias.

Results: Survivin was an independent predictor of disease recurrence and cancer-specific survival in multivariable analyses that controlled for the effects of standard clinicopathologic features (hazard ratios, 1.6; P values 0.002). In all patients (n = 726), addition of survivin to a model including standard clinicopathologic variables did not improve its predictive accuracy (P = 0.67 for disease recurrence and P = 0.27 for cancer-specific survival). In the subgroup of patients with pT1-3N0M0 disease (n = 398), addition of survivin improved the accuracy of standard clinicopathologic features for prediction of disease recurrence and cancer-specific survival (1.3, P < 0.001 and 1.2, P < 0.001, respectively).

Conclusions: Survivin expression improves our accuracy for prediction of cancer recurrence and survival in pT1-3N0M0 patients by a small but statistically significant margin. Our findings support the need for further evaluation of survivin and its signaling pathways as well as survivin-targeted therapies in bladder cancer. (Clin Cancer Res 2009;15(22):70129)
HIF-1α and HIF-2α Are Differentially Regulated In vivo in Neuroblastoma: High HIF-1α Correlates Negatively to Advanced Clinical Stage and Tumor Vascularization
Authors: Noguera Rosa , Fredlund Erik , Piqueras Marta , Pietras Alexander , Beckman Siv , Navarro Samuel , Påhlman Sven
Published: November 2009

Purpose: Hypoxia is considered to be a major driving force behind tumor angiogenesis. The stabilization and activation at hypoxia of the hypoxia-inducible factors HIF-1α and HIF-2α and the concomitant induction of expression of vascular endothelial growth factor (VEGF) and other proangiogenic factors provide a molecular frame for hypoxia-driven tumor angiogenesis. This study has investigated how HIF and VEGF protein levels relate to each other with regard to vascularization, tumor stage, and overall survival in neuroblastoma.

Experimental Design: Tissue cores taken from tumor specimens representing 93 children with neuroblastoma were arranged on a microarray and stained for HIF-1α, HIF-2α, VEGF, and CD31 proteins. Both fraction of positive cells and staining intensity were evaluated and protein levels were correlated with each other and with clinical variables.

Results: Although high levels of both HIF-1α (P < 0.001) and HIF-2α (P < 0.001) correlated positively to VEGF expression, they did not fully correlate with each other. Moreover, HIF-1α (P = 0.002) and VEGF (P < 0.001), but not HIF-2α, correlated negatively to vascularization as determined by CD31 staining abundance. VEGF expression or degree of vascularization did not correlate with tumor stage or overall survival. High HIF-1α levels correlated with low tumor stage (P < 0.001) and were associated with a favorable patient prognosis (P = 0.08).

Conclusions: The discordant results on expression of HIF-1α and HIF-2α suggest that these two proteins are differentially regulated in vivo, thus reflecting distinctive protein expression/stabilization mechanisms. The association between HIF-1α and favorable outcome stresses the importance of discriminating HIF-2α from HIF-1α expression and has implications for using HIFs as treatment targets. (Clin Cancer Res 2009;15(23):7130–6)
Subsets of Very Low Risk Wilms Tumor Show Distinctive Gene Expression, Histologic, and Clinical Features
Authors: Sredni Simone T. , Gadd Samantha , Huang Chiang-Ching , Breslow Norman , Grundy Paul , Green Daniel M. , Dome Jeffrey S. , Shamberger Robert C. , Beckwith J. Bruce , Perlman Elizabeth J. ,   for the Renal Tumor Committee of the Children's Oncology Group
Published: November 2009

Purpose: Recent studies suggest that children <24 months with stage I favorable histology Wilms tumors <550 g [very low risk Wilms tumors (VLRWT)] have an excellent prognosis when treated with nephrectomy only, without adjuvant chemotherapy. The identification of risk categories within VLRWT may enable refinement of their definition and optimization of their therapy.

Experimental Design: To define biologically distinct subsets, global gene expression analysis was done on 39 VLRWT that passed all quality-control parameters and the clusters identified were validated in an independent set of 11 VLRWT. Validation of select differentially expressed genes was done with immunohistochemistry on a tissue microarray from 20 of 39 tumors. Loss of heterozygosity (LOH) for 11p15, 1p, and 16q was analyzed in 52 tumors using PCR.

Results: Two distinctive clusters were identified. One cluster included 9 tumors with epithelial differentiated tubular histology, paucity of nephrogenic rests, lack of LOH for 1p, 16q, and 11p, absence of relapse, and a unique gene expression profile consistent with arrest following mesenchymal-to-epithelial transition. The second cluster included 13 tumors with mixed histology, intralobar nephrogenic rests, and decreased expression of WT1. Three of 6 relapses occurred in this cluster. Of 43 informative tumors, 11p LOH was present in 5 of 5 relapses and 11 of 38 nonrelapses.

Conclusions: Two subsets comprising a total of 56 of VLRWT are identified that have pathogenetic and molecular differences and apparent differences in risk for relapse. If these predictors can be prospectively validated, this would enable the refinement of clinical stratification and less arbitrary definition of VLRWT. (Clin Cancer Res 2009;15(22):68009)
A Phase 1 Dose Escalation Study of the Safety and Pharmacokinetics of the Novel Proteasome Inhibitor Carfilzomib (PR-171) in Patients with Hematologic Malignancies
Authors: O'Connor Owen A. , Stewart A. Keith , Vallone Marcy , Molineaux Christopher J. , Kunkel Lori A. , Gerecitano John F. , Orlowski Robert Z.
Published: November 2009

Purpose: Carfilzomib (formerly PR-171) is a novel proteasome inhibitor of the epoxyketone class that is selective and structurally distinct from bortezomib. Proteasome inhibition by carfilzomib is mechanistically irreversible. Consequently, proteasome inhibition is more sustained with carfilzomib than with bortezomib.

Experimental Design: In a phase 1 trial evaluating the safety and efficacy of carfilzomib in relapsed or refractory hematologic malignancies, eight dose groups of three to six patients received 5 consecutive days of carfilzomib i.v. push at doses of 1.2, 2.4, 4, 6, 8.4, 11, 15, and 20 mg/m2 within 14-day cycles.

Results: Twenty-nine patients enrolled that were relapsed or refractory after at least two prior therapies. Nonhematologic toxicities included fatigue, nausea, and diarrhea in more than one third of patientsmostly grade 1 or 2 in severity. At 20 mg/m2, grade 3 febrile neutropenia and grade 4 thrombocytopenia were reported, establishing 15 mg/m2 as the maximum tolerated dose. No grade 3 or 4 peripheral neuropathies were reported. Antitumor activity was observed at doses 11 mg/m2: one unconfirmed complete response (mantle cell), one partial response (multiple myeloma), and two minimal responses (multiple myeloma and Waldenstrm's macroglobulinemia).

Conclusion: This is the first clinical use of carfilzomib that shows tolerability and clinical activity in multiple hematologic malignancies using consecutive-day dosing. (Clin Cancer Res 2009;15(22):708591)
Deregulated GSK3 Sustains Gastrointestinal Cancer Cells Survival by Modulating Human Telomerase Reverse Transcriptase and Telomerase
Authors: Mai Wei , Kawakami Kazuyuki , Shakoori Abbas , Kyo Satoru , Miyashita Katsuyoshi , Yokoi Kenji , Jin Mingji , Shimasaki Takeo , Motoo Yoshiharu , Minamoto Toshinari
Published: November 2009

Purpose: Glycogen synthase kinase-3 (GSK3) regulates multiple cell signaling pathways and has been implicated in glucose intolerance, neurodegenerative disorders, and inflammation. We investigated the expression, activity, and putative pathologic role of GSK3 in gastrointestinal, pancreatic, and liver cancers.

Experimental Design: Colon, stomach, pancreatic, and liver cancer cell lines; nonneoplastic HEK293 cells; and matched pairs of normal and tumor tissues of stomach and colon cancer patients were examined for GSK3 expression and its phosphorylation at serine 9 (inactive form) and tyrosine 216 (active form) by Western immunoblotting and for GSK3 activity by in vitro kinase assay. The effects of small-molecule GSK3 inhibitors and of RNA interference on cell survival, proliferation, and apoptosis were examined in vitro and on human colon cancer cell xenografts in athymic mice. The effects of GSK3 inhibition on human telomerase reverse transcriptase (hTERT) expression and telomerase activity were compared between colon cancer and HEK293 cells.

Results: Cancer cell lines and most cancer tissues showed increased GSK3 expression and increased tyrosine 216 phosphorylation and activity but decreased serine 9 phosphorylation compared with HEK293 cells and nonneoplastic tissues. Inhibition of GSK3 resulted in attenuated cell survival and proliferation and increased apoptosis in most cancer cell lines and in HT-29 xenografts in rodents but not in HEK293 cells. GSK3 inhibition in colon cancer cells was associated with decreased hTERT expression and telomerase activity.

Conclusion: The results indicate that deregulated GSK3 sustains gastrointestinal cancer cells survival through modulation of hTERT and telomerase. (Clin Cancer Res 2009;15(22):68109)
Partial CD4 Depletion Reduces Regulatory T Cells Induced by Multiple Vaccinations and Restores Therapeutic Efficacy
Authors: LaCelle Michael G. , Jensen Shawn M. , Fox Bernard A.
Published: November 2009

Purpose: A single vaccination of intact or reconstituted-lymphopenic mice (RLM) with a granulocyte macrophage colony-stimulating factorsecreting B16BL6-D5 melanoma cell line induces protective antitumor immunity and T cells that mediate the regression of established melanoma in adoptive immunotherapy studies. We wanted to study if multiple vaccinations during immune reconstitution of the lymphopenic host would maintain a potent antitumor immune response.

Experimental Design: RLM were vaccinated multiple times over a 40-day period. Spleens were isolated from these mice, activated in vitro, and adoptively transferred into mice bearing 3-day experimental pulmonary metastases.

Results: Multiple vaccinations, rather than boosting the immune response, significantly reduced therapeutic efficacy of adoptive immunotherapy and were associated with an increased frequency and absolute number of CD3+CD4+Foxp3+ T regulatory (Treg) cells. Anti-CD4 administration reduced the absolute number of Treg cells 9-fold. Effector T-cells generated from anti-CD4treated mice were significantly (P < 0.0001) more therapeutic in adoptive transfer studies than T cells from multiply vaccinated animals with a full complement of CD4+ cells.

Conclusion: These results suggest that CD4+ Treg cells limit the efficacy of multiple vaccinations and that timed partial depletion of CD4+ T cells may reduce suppression and tip-the-balance in favor of therapeutic antitumor immunity. The recent failure of large phase III cancer vaccine clinical trials, wherein patients received multiple vaccines, underscores the potential clinical relevance of these findings. (Clin Cancer Res 2009;15(22):688190)