bluuebunny/crossref_metadata_2025 huggingface dataset:
The Tumor Suppressor Gene hCDC4 Is Frequently Mutated in Human T-Cell Acute Lymphoblastic Leukemia with Functional Consequences for Notch Signaling
Authors: Malyukova Alena , Dohda Takeaki , von der Lehr Natalie , Akhondi Shahab , Corcoran Martin , Heyman Mats , Spruck Charles , Grandér Dan , Lendahl Urban , Sangfelt Olle
Published: June 2007

Notch signaling is of crucial importance in normal T-cell development and Notch 1 is frequently mutated in T-cell acute lymphoblastic leukemias (T-ALL), leading to aberrantly high Notch signaling. In this report, we determine whether T-ALL mutations occur not only in Notch1 but also in the F-box protein hCdc4 (Sel-10, Ago, or Fbxw7), a negative regulator of Notch1. We show that the hCDC4 gene is mutated in leukemic cells from more than 30% of patients with pediatric T-ALL and derived cell lines. Most hCDC4 mutations found were missense substitutions at critical arginine residues (Arg465, Arg479, and Arg505) localized in the substrate-binding region of hCdc4. Cells inactivated for hCdc4 and T-ALL cells containing hCDC4 mutations exhibited an increased Notch1 protein half-life, consistent with the proposed role of hCdc4 in ubiquitin-dependent proteolysis of Notch1. Furthermore, restoration of wild-type but not mutant hCdc4 in HCT 116 hCDC4-negative cells led to an increased Notch1 ubiquitylation and decreased Notch1 signaling. These results show that hCdc4 mutations interfere with normal Notch1 regulation in vivo. Finally, we found that mutations in hCDC4 and NOTCH1 can occur in the same cancers and that patients carrying hCDC4 and/or NOTCH1 mutations have a favorable overall survival. Collectively, these data show that mutation of hCDC4 is a frequent event in T-ALL and suggest that hCDC4 mutations and gain-of-function mutations in NOTCH1 might synergize in contributing to the development of pediatric T-ALL leukemogenesis. [Cancer Res 2007;67(12):5611–6]
Membrane-Bound Interleukin (IL)-15 on Renal Tumor Cells Rescues Natural Killer Cells from IL-2 Starvation-Induced Apoptosis
Authors: Wittnebel Sebastian , Da Rocha Sylvie , Giron-Michel Julien , Jalil Abdelali , Opolon Paule , Escudier Bernard , Validire Pierre , Khawam Krystel , Chouaib Salem , Azzarone Bruno , Caignard Anne
Published: June 2007

Renal cell carcinoma primary tumors and lung metastases are infiltrated by activated natural killer (NK) cells. Interleukin (IL)-15, a major cytokine involved in cross-talk between accessory cells (dendritic cells and macrophages) and NK cells, is produced by epithelial renal cells. We show that renal cell carcinoma cells and normal renal cells express IL-15 mRNA and membrane-bound IL-15 (MbIL-15). These cells also express IL-15 receptor α (IL-15Rα). Silencing of IL-15Rα by specific small interfering RNA in renal cell carcinoma had no effect on MbIL-15 production, indicating that the cytokine is not cross-presented by IL-15Rα in renal cell carcinoma cells but anchored to the membrane. Furthermore, we show that MbIL-15 from renal cell carcinoma cells is functional and involved in rapid nuclear translocation of phosphorylated signal transducers and activators of transcription 3 in IL-2–starved NK cells. MbIL-15 on the target did not interfere with resting NK cell activation and target cell cytolysis but rescued NK cells from IL-2 starvation-induced apoptosis through contact-dependent interaction. Masking of MbIL-15 with soluble IL-15Rα molecules restored NK cell apoptosis. These findings suggest that IL-15 produced by renal tumor cells is involved in the maintenance of active NK cells at the tumor site. [Cancer Res 2007;67(12):5594–9]
Oncogenic Potential of the miR-106-363 Cluster and Its Implication in Human T-Cell Leukemia
Authors: Landais Séverine , Landry Sébastien , Legault Philippe , Rassart Eric
Published: June 2007

We previously reported the identification of the Kis2 common retrovirus integration site, located on mouse chromosome X, in radiation leukemia virus–induced T-cell leukemias. Tumors with a provirus at the Kis2 locus overexpressed a novel noncoding RNA (ncRNA) with a complex splicing pattern and no polyA tail. Database upgrade revealed the presence of a microRNA (miRNA) cluster, miR-106-363, just downstream of the Kis2 ncRNAs. We found that Kis2 ncRNAs are the pri-miRNA of miR-106-363, and we present evidence that Kis2 ncRNA overexpression in mouse tumors results in miR-106a, miR-19b-2, miR-92-2, and miR-20b accumulation. We show the oncogenic potential of those miRNAs in anchorage independence assay and confirm pri-miR-106-363 overexpression in 46% of human T-cell leukemias tested. This overexpression contributes in rising miR-92 and miR-19 levels, as this is the case for miR-17-92 cluster overexpression. Furthermore, we identified myosin regulatory light chain–interacting protein, retinoblastoma-binding protein 1-like, and possibly homeodomain-interacting protein kinase 3 as target genes of this miRNA cluster, which establishes a link between these genes and T-cell leukemia for the first time. [Cancer Res 2007;67(12):5699–707]
MutantPIK3CA-Bearing Colon Cancer Cells Display Increased Metastasis in an Orthotopic Model
Authors: Guo Xiao-Ning , Rajput Ashwani , Rose Rebecca , Hauser Jennie , Beko Alexander , Kuropatwinski Karen , LeVea Charles , Hoffman Robert M. , Brattain Michael G. , Wang Jing
Published: June 2007

Mutations in the PIK3CA gene are common in human cancers, including colon cancer. We compared two pairs of colon cancer cells (HCT116 and DLD1) bearing only the wild-type (WT) or mutant (MUT) PIK3CA allele for their survival capacity under stress conditions in vitro as well as their metastatic properties in an in vivo orthotopic model. When subjected to growth factor deprivation stress (GFDS), the MUT PIK3CA cells displayed resistance to GFDS-induced apoptosis relative to the WT cells. Phosphatidylinositol 3-kinase (PI3K) and its downstream effector AKT were constitutively activated during stress conditions in the MUT PIK3CA cells but not in the WT cells. The MUT cells showed hypersensitivity to PI3K inhibition. Moreover, the proapoptotic protein Bax was expressed at a very high level in the WT PIK3CA cells, whereas it was almost undetectable in the MUT cells. Inhibition of Bax expression by small interfering RNA protected the WT PIK3CA cells from GFDS-induced apoptosis, suggesting an important role of Bax in GFDS-induced apoptosis. These results indicated that the MUT PI3K confers resistance to GFDS-induced apoptosis and that the MUT cells are more dependent on the PI3K pathway for survival. In vivo studies showed that the MUT PIK3CA-bearing cells were more metastatic than the WT cells in an orthotopic model of colon cancer. Taken together, these results suggest that MUT PI3K imparts a more aggressive phenotype in colon cancer cells and could be a potential therapeutic target for treatment of colon cancer patients bearing PIK3CA mutations. [Cancer Res 2007;67(12):5851–8]
Effects of Tetramethoxystilbene on Hormone-Resistant Breast Cancer Cells: Biological and Biochemical Mechanisms of Action
Authors: Park Hoyong , Aiyar Sarah E. , Fan Ping , Wang Jiping , Yue Wei , Okouneva Tatiana , Cox Corey , Jordan Mary Ann , Demers Laurence , Cho Hyungjun , Kim Sanghee , Song Robert X.-D. , Santen Richard J.
Published: June 2007

Secondary resistance to hormonal therapy for breast cancer commonly develops after an initial response to tamoxifen or aromatase inhibitors. Agents to abrogate these adaptive changes would substantially enhance the long-term benefits of hormonal therapy. Our studies with a stilbene derivative called TMS (2,3′,4,5′-tetramethoxystilbene) identified unexpected effects with potential utility for treatment of breast tumors secondarily resistant to hormonal therapy. TMS was originally developed as an inhibitor of cytochrome P450 1B1 to block the conversion of estradiol to 4-OH-estradiol. While studying this agent in three models of hormone resistance, we detected direct antitumor effects not related to its role as an inhibitor of catecholestrogens. During examination of the mechanisms involved, we showed that treatment with 3 μmol/L TMS for 24 h inhibited tubulin polymerization and microtubule formation, caused a cell cycle block at the G2-M phase, and induced apoptosis. TMS also inhibited activated focal adhesion kinase (FAK), Akt, and mammalian target of rapamycin (mTOR) and stimulated c-jun-NH2-kinase and p38 mitogen-activated protein kinase activity. With respect to antitumor effects, TMS at a concentrations of 0.2 to 0.3 μmol/L inhibited the growth of long-term tamoxifen-treated MCF-7 cells by 80% and fulvestrant-treated MCF-7 cells by 70%. In vivo studies, involving 8 weeks of treatment with TMS via a 30-mg s.c. implant, reduced tumor volume of tamoxifen-resistant MCF-7 breast cancer xenografts by 53%. Our data suggest that TMS is a promising therapeutic agent because of its unique ability to block several pathways involved in the development of hormone resistance. [Cancer Res 2007;67(12):5717–26]
Evaluation of CD20, CD22, and HLA-DR Targeting for Radioimmunotherapy of B-Cell Lymphomas
Authors: Pagel John M. , Pantelias Anastasia , Hedin Nathan , Wilbur Shani , Saganic Laura , Lin Yukang , Axworthy Donald , Hamlin Donald K. , Wilbur D. Scott , Gopal Ajay K. , Press Oliver W.
Published: June 2007

Despite the promise of radioimmunotherapy using anti-CD20 antibodies (Ab) for the treatment of relapsed patients with indolent non-Hodgkin lymphoma (NHL), most patients treated with conventional doses of 131I-tositumomab or 90Y-ibritumomab eventually relapse. We did comparative assessments using conventional radioimmunotherapy targeting CD20, CD22, and HLA-DR on human Ramos, Raji, and FL-18 lymphoma xenografts in athymic mice to assess the potential for improving the efficacy of radioimmunotherapy by targeting other NHL cell surface antigens. Results of biodistribution studies showed significant differences in tumor localization consistent with variable antigenic expression on the different lymphoma cell lines. Interestingly, the radioimmunoconjugate that yielded the best tumor-to-normal organ ratios differed in each tumor model. We also explored administering all three 111In-1,4,7,10-tetra-azacylododecane N,N′,N″,N‴-tetraacetic acid antibodies in combination, but discovered, surprisingly, that this approach did not augment the localization of radioactivity to tumors compared with the administration of the best single radiolabeled Ab alone. These data suggest that conventional radioimmunotherapy using anti-CD20, anti–HLA-DR, or anti-CD22 Abs is effective when used singly and provides targeted uptake of radiolabel into the tumor that is dependent on the levels of antigen expression. Improvements in tumor-to-normal organ ratios of radioactivity cannot be achieved using directly labeled Abs in combination but may be afforded by novel pretargeting methods. [Cancer Res 2007;67(12):5921–8]
MPC-6827: A Small-Molecule Inhibitor of Microtubule Formation That Is Not a Substrate for Multidrug Resistance Pumps
Authors: Kasibhatla Shailaja , Baichwal Vijay , Cai Sui Xiong , Roth Bruce , Skvortsova Ira , Skvortsov Sergej , Lukas Peter , English Nicole M. , Sirisoma Nilantha , Drewe John , Pervin Azra , Tseng Ben , Carlson Robert O. , Pleiman Christopher M.
Published: June 2007

A novel series of 4-arylaminoquinazolines were identified from a cell-based screening assay as potent apoptosis inducers. Through structure-activity relationship studies, MPC-6827 and its close structural analogue, MPI-0441138, were discovered as proapoptotic molecules and mitotic inhibitors with potencies at low nanomolar concentrations in multiple tumor cell lines. Photoaffinity and radiolabeled analogues of MPC-6827 were found to bind a 55-kDa protein, and this binding was competed by MPC-6827, paclitaxel, and colchicine, but not vinblastine. MPC-6827 effectively inhibited the polymerization of tubulin in vitro, competed with colchicine binding, and disrupted the formation of microtubules in a variety of tumor cell lines, which together showed the molecular target as tubulin. Treatment of MCF-7 breast carcinoma or Jurkat leukemia cells with MPC-6827 led to pronounced G2-M cell cycle arrest followed by apoptosis. Apoptosis, as determined by terminal deoxyribonucleotidyl transferase–mediated dUTP nick end labeling assay, was preceded by loss of mitochondrial membrane potential, cytochrome c translocation from mitochondria to nuclei, activation of caspase-3, and cleavage of poly(ADP-ribose) polymerase. MPC-6827 was equipotent in an in vitro growth inhibition assay in several cancer cell lines regardless of the expression levels of the multidrug resistance ABC transporters MDR-1 (Pgp-1), MRP-1, and BCRP-1. In B16-F1 allografts and in OVCAR-3, MIAPaCa-2, MCF-7, HT-29, MDA-MB-435, and MX-1 xenografts, statistically significant tumor growth inhibition was observed with MPC-6827. These studies show that MPC-6827 is a microtubule-disrupting agent with potent and broad-spectrum in vitro and in vivo cytotoxic activities and, therefore, MPC-6827 is a promising candidate for development as a novel therapeutic for multiple cancer types. [Cancer Res 2007;67(12):5865–71]
CD133 Is Not Present on Neurogenic Astrocytes in the Adult Subventricular Zone, but on Embryonic Neural Stem Cells, Ependymal Cells, and Glioblastoma Cells
Authors: Pfenninger Cosima V. , Roschupkina Teona , Hertwig Falk , Kottwitz Denise , Englund Elisabet , Bengzon Johan , Jacobsen Sten Eirik , Nuber Ulrike A.
Published: June 2007

Human brain tumor stem cells have been enriched using antibodies against the surface protein CD133. An antibody recognizing CD133 also served to isolate normal neural stem cells from fetal human brain, suggesting a possible lineage relationship between normal neural and brain tumor stem cells. Whether CD133-positive brain tumor stem cells can be derived from CD133-positive neural stem or progenitor cells still requires direct experimental evidence, and an important step toward such investigations is the identification and characterization of normal CD133-presenting cells in neurogenic regions of the embryonic and adult brain. Here, we present evidence that CD133 is a marker for embryonic neural stem cells, an intermediate radial glial/ependymal cell type in the early postnatal stage, and for ependymal cells in the adult brain, but not for neurogenic astrocytes in the adult subventricular zone. Our findings suggest two principal possibilities for the origin of brain tumor stem cells: a derivation from CD133-expressing cells, which are normally not present in the adult brain (embryonic neural stem cells and an early postnatal intermediate radial glial/ependymal cell type), or from CD133-positive ependymal cells in the adult brain, which are, however, generally regarded as postmitotic. Alternatively, brain tumor stem cells could be derived from proliferative but CD133-negative neurogenic astrocytes in the adult brain. In the latter case, brain tumor development would involve the production of CD133. [Cancer Res 2007;67(12):5727–36]
Cytoplasmic Irradiation Induces Mitochondrial-Dependent 53BP1 Protein Relocalization in Irradiated and Bystander Cells
Authors: Tartier Laurence , Gilchrist Stuart , Burdak-Rothkamm Susanne , Folkard Melvyn , Prise Kevin M.
Published: June 2007

The accepted paradigm for radiation effects is that direct DNA damage via energy deposition is required to trigger the downstream biological consequences. The radiation-induced bystander effect is the ability of directly irradiated cells to interact with their nonirradiated neighbors, which can then show responses similar to those of the targeted cells. p53 binding protein 1 (53BP1) forms foci at DNA double-strand break sites and is an important sensor of DNA damage. This study used an ionizing radiation microbeam approach that allowed us to irradiate specifically the nucleus or cytoplasm of a cell and quantify response in irradiated and bystander cells by studying ionizing radiation-induced foci (IRIF) formation of 53BP1 protein. Our results show that targeting only the cytoplasm of a cell is capable of eliciting 53BP1 foci in both hit and bystander cells, independently of the dose or the number of cells targeted. Therefore, direct DNA damage is not required to trigger 53BP1 IRIF. The use of common reactive oxygen species and reactive nitrogen species (RNS) inhibitors prevent the formation of 53BP1 foci in hit and bystander cells. Treatment with filipin to disrupt membrane-dependent signaling does not prevent the cytoplasmic irradiation-induced 53BP1 foci in the irradiated cells, but it does prevent signaling to bystander cells. Active mitochondrial function is required for these responses because pseudo-ρ0 cells, which lack mitochondrial DNA, could not produce a bystander signal, although they could respond to a signal from normal ρ+ cells. [Cancer Res 2007;67(12):5872–9]
Tunicamycin Sensitizes Human Melanoma Cells to Tumor Necrosis Factor–Related Apoptosis-Inducing Ligand–Induced Apoptosis by Up-regulation of TRAIL-R2 via the Unfolded Protein Response
Authors: Jiang Chen Chen , Chen Li Hua , Gillespie Susan , Kiejda Kelly A. , Mhaidat Nizar , Wang Yu Fang , Thorne Rick , Zhang Xu Dong , Hersey Peter
Published: June 2007

We have reported previously low expression of death receptors for tumor necrosis factor (TNF)–related apoptosis-inducing ligand (TRAIL) in fresh isolates and tissue sections of melanoma. This seemed to correlate with relative resistance of freshly isolated melanoma cells to TRAIL-induced apoptosis. We show in this study that the endoplasmic reticulum (ER) stress inducer, tunicamycin, selectively up-regulated the cell surface expression of TRAIL-R2, but not other members of the TNF receptor family, and enhanced TRAIL-induced apoptosis in cultured melanoma cells and fresh melanoma isolates. Tunicamycin-mediated sensitization of melanoma cells to TRAIL-induced apoptosis was associated with increased activation of the caspase cascade and reduction in mitochondrial membrane potential and was inhibited by a recombinant TRAIL-R2/Fc chimeric protein. Up-regulation of TRAIL-R2 on the melanoma cell surface was associated with increased transcription of TRAIL-R2 and its total protein levels. Two signaling pathways of the ER stress-induced unfolded protein response mediated by inositol-requiring transmembrane kinase and endonuclease 1α (IRE1α) and activation of transcription factor 6 (ATF6), respectively, seemed to be involved. In one melanoma line, there was clear evidence of activation of the IRE1α pathway, and small interfering RNA (siRNA) knockdown of IRE1α substantially reduced the up-regulation of TRAIL-R2. Similarly, there was evidence for the activation of the ATF6 pathway, and siRNA knockdown of ATF6 had a delayed effect on TRAIL-R2 expression in one but not another melanoma cell line. Moreover, the transcription factor CCAAT/enhancer-binding protein homologous protein seemed to be involved in the up-regulation of TRAIL-R2 by tunicamycin, but its role varied between different melanoma lines. Taken together, our results suggest that agents that induce ER stress may enhance TRAIL-R2 expression and increase the therapeutic response to TRAIL in melanoma. [Cancer Res 2007;67(12):5880–8]
Transforming Growth Factor-β Signaling in Prostate Stromal Cells Supports Prostate Carcinoma Growth by Up-regulating Stromal Genes Related to Tissue Remodeling
Authors: Verona Erik V. , Elkahloun Abdel G. , Yang Junhua , Bandyopadhyay Abhik , Yeh I-Tien , Sun Lu-Zhe
Published: June 2007

Increasing evidence points to an active stromal involvement in cancer initiation and progression. Cytokines derived from tumor cells are believed to modulate stromal cells to produce growth and angiogenic factors, which in turn provide the tumor with the necessary microenvironment for expansion and invasion. Transforming growth factor β (TGFβ) has been implicated as a candidate cytokine to mediate this communication. However, how its signaling in stromal cells regulates tumorigenesis and tumor progression remains unresolved. We show that normal, presenescent fibroblasts or prostate stromal cells cotransplanted with prostate carcinoma cells s.c. into nude mice reduced tumor latency and accelerated tumor growth. When their TGFβ signaling was blocked, the fibroblasts and stromal cells still stimulated tumor initiation but no longer supported tumor growth as control cells did. The loss of the tumor growth–promoting activity of the stromal cells with attenuated TGFβ signaling was not associated with altered cellular senescence or tumor angiogenicity. TGFβ and the medium conditioned by the prostate carcinoma cells stimulated myofibroblast differentiation of the intact stromal cells, but not the stromal cells with attenuated TGFβ signaling. Gene microarray and quantitative reverse transcription-PCR analyses showed that TGFβ up-regulated a host of genes in stromal cells that are involved in tissue remodeling and wound healing. Thus, our study provides evidence for TGFβ as a supporting agent in tumor progression through the induction of a perpetual wound healing process in the tumor microenvironment. [Cancer Res 2007;67(12):5737–46]
Haplotype Analysis of CYP11A1 Identifies Promoter Variants Associated with Breast Cancer Risk
Authors: Yaspan Brian L. , Breyer Joan P. , Cai Qiuyin , Dai Qi , Elmore J. Bradford , Amundson Isaac , Bradley Kevin M. , Shu Xiao-Ou , Gao Yu-Tang , Dupont William D. , Zheng Wei , Smith Jeffrey R.
Published: June 2007

The CYP11A1 gene encodes the cholesterol side chain cleavage enzyme that catalyzes the initial and rate-limiting step of steroidogenesis. A large number of epidemiologic studies have implicated the duration and degree of endogenous estrogen exposure in the development of breast cancer in women. Here, we conduct a systematic investigation of the role of genetic variation of the CYP11A1 gene in breast cancer risk in a study of 1193 breast cancer cases and 1310 matched controls from the Shanghai Breast Cancer Study. We characterize the genetic architecture of the CYP11A1 gene in a Chinese study population. We then genotype tagging polymorphisms to capture common variation at the locus for tests of association. Variants designating a haplotype encompassing the gene promoter are significantly associated with both increased expression (P = 1.6e−6) and increased breast cancer risk: heterozygote age-adjusted odds ratio (OR), 1.51 [95% confidence interval (95% CI), 1.19–1.91]; homozygote age-adjusted OR, 2.94 (95% CI, 1.22–7.12), test for trend, P = 5.0e−5. Among genes controlling endogenous estrogen metabolism, CYP11A1 harbors common variants that may influence expression to significantly modify risk of breast cancer. [Cancer Res 2007;67(12):5673–82]
Targeting the Loss of the von Hippel-Lindau Tumor Suppressor Gene in Renal Cell Carcinoma Cells
Authors: Sutphin Patrick D. , Chan Denise A. , Li James M. , Turcotte Sandra , Krieg Adam J. , Giaccia Amato J.
Published: June 2007

Late-stage clear cell renal carcinoma poses a formidable clinical challenge due to the high mortality rate associated with this disease. Molecular and genetic studies have identified functional loss of the von Hippel-Lindau (VHL) gene as a frequent and crucial event in the development of the malignant phenotype of clear cell renal carcinomas. Loss of VHL function thus represents a pathognomonic molecular defect for therapeutic exploitation. The objective of this study was to evaluate the possibility of targeting VHL loss through pharmacologic means. Chromomycin A3 (ChA3) was identified through in silico analysis of existing publicly available drug profiles from the National Cancer Institute as an agent that seemed to selectively target VHL-deficient clear cell renal carcinoma cells. Genotype-selective toxicity was first determined through short-term viability assays and then confirmed with clonogenic studies. Coculture of fluorescently labeled VHL-deficient and VHL-positive cells showed discriminate killing of the VHL-deficient cells with ChA3. Mechanistically, overexpression of hypoxia-inducible factor (HIF)-2α in VHL-positive clear cell renal carcinoma cells phenocopied loss of VHL with respect to ChA3 toxicity, establishing ChA3 as a HIF-dependent cytotoxin. This study shows the feasibility of selectively targeting the loss of the VHL tumor suppressor gene in clear cell renal carcinoma for potential clinical benefit and may have greater ramifications in the development of new targeted therapies for the treatment of cancer and other genetic diseases. [Cancer Res 2007;67(12):5896–905]
Initial Analyses of Colon Cancer–Specific Antigen (CCSA)-3 and CCSA-4 as Colorectal Cancer–Associated Serum Markers
Authors: Leman Eddy S. , Schoen Robert E. , Weissfeld Joel L. , Cannon Grant W. , Sokoll Lori J. , Chan Daniel W. , Getzenberg Robert H.
Published: June 2007

Colon cancer–specific antigen (CCSA)-3 and CCSA-4 are novel colon cancer markers identified by focused proteomic analysis of nuclear structural proteins. The goal of these studies was to evaluate serum-based CCSA-3 and CCSA-4 in the detection of individuals with preneoplastic and neoplastic lesions using ELISAs. Serum samples from 107 subjects undergoing colonoscopy, 28 subjects with colorectal cancer, and 125 subjects with benign disease or other types of cancer were evaluated. Individuals who underwent colonoscopy were classified into mutually exclusive categories, including normal colon, hyperplastic polyp, nonadvanced adenoma, and advanced adenoma. Sensitivity and specificity for both CCSA-3 and CCSA-4 were evaluated using receiver operating characteristic (ROC) curves. At a cutoff of 2 μg/mL for CCSA-3 and 0.3 μg/mL for CCSA-4, each marker detected all 28 colorectal cancers, for a sensitivity of 100% (lower 95% confidence bound, 89.8%). The sensitivity for detection of the combined end point of colorectal cancer and advanced adenoma for CCSA-3 was 89.1% [95% confidence interval (95% CI), 76.4–96.4%] and for CCSA-4 was 84.8% (95% CI, 71.1–93.7%) and 91.3% (95% CI, 79.2–97.6%) for either marker positive. The specificity in individuals with normal, hyperplastic polyps, or nonadvanced adenomas was 82.0% (95% CI, 72.4–89.4%) and 91.0% (95% CI, 83.0–96.0%) for CCSA-3 and CCSA-4, respectively. ROC curves for CCSA-3 and CCSA-4 reveal an area under the curve of 0.94 (95% CI, 0.90–0.98%). In these initial analyses, CCSA-3 and CCSA-4 show promise as potential serum markers for detection of colorectal cancer and advanced adenomas. [Cancer Res 2007;67(12):5600–5]
A Novel Role for p73 in the Regulation of Akt-Foxo1a-Bim Signaling and Apoptosis Induced by the Plant Lectin, Concanavalin A
Authors: Amin A.R.M. Ruhul , Paul Rajib K. , Thakur Vijay S. , Agarwal Munna L.
Published: June 2007

Virtually all human cancers encounter disruption of the “p53 network.” From a therapeutic point of view, it is important to devise strategies that eliminate cancer cells, which are often defective in functional p53 and protect p53-expressing normal cells. By comparing the response of a pair of isogenic cell lines, we identify a plant-derived compound, Concanavalin A (Con A), which differentially kills p53-null cells. Further, we find that p53 family member, p73, plays a critical role that is unmasked in the absence of p53. Con A treatment leads to induction of p73 and several others that are important mediators of apoptosis and act downstream, such as p21, Bax, Foxo1a, and Bim. Inactivation of p73 reverses the expression of these proteins and apoptosis. Inhibition of Akt activation sensitizes otherwise resistant cells. These observations thus reveal a novel role for p73 in the regulation of Akt-Foxo1a-Bim signaling and apoptosis especially when p53 is absent. [Cancer Res 2007;67(12):5617–21]
Tumorigenesis in the Brain: Location, Location, Location
Authors: Gilbertson Richard J. , Gutmann David H.
Published: June 2007

Emerging evidence from numerous laboratories supports the notion that brain tumors arise from cells with stem cell/neuroglial progenitor cell properties (“cancer stem cells”). Two recent studies suggest that histologically similar tumors from different brain regions are molecularly distinct because they arise from distinct populations of site-restricted progenitor cells. These new findings imply an interaction between the cell of origin, the tumor microenvironment, and specific cancer-causing genetic changes in the evolution of central nervous system tumors. [Cancer Res 2007;67(12):5579–82]
LKB1 Catalytically Deficient Mutants Enhance Cyclin D1 Expression
Authors: Scott Kristine D. , Nath-Sain Suchita , Agnew Meghan D. , Marignani Paola A.
Published: June 2007

Mutations in the serine-threonine tumor-suppressor kinase LKB1 are responsible for Peutz-Jeghers syndrome, characterized by hamartomatous proliferation and an increased risk of developing cancer. Mutations in lkb1 have also been identified in sporadic cancers, suggesting a wider role for LKB1 in cancer that is not limited to hamartomatous polyposis syndromes. Here, we show that LKB1 catalytically deficient mutants, when introduced into DLD1p21−/−p53−/− colorectal cancer cells, allowed for progression of cells through to S phase of cell cycle and elicited the expression of Rb, cyclin E, and cyclin A2 whereas the introduction of LKB1 lead to G1 cell cycle arrest independent of p21WAF/CIP1 and/or p53 expression. Furthermore, we show that LKB1 catalytically deficient mutants activate the expression of cyclin D1 through recruitment to response elements within the promoter of the oncogene. In addition to compromising the tumor-suppressor function of LKB1, our findings highlight an emerging role for LKB1 catalytically deficient mutants, a gain of oncogenic properties. [Cancer Res 2007;67(12):5622–7]
Inflammation-Mediated Cytosine Damage: A Mechanistic Link between Inflammation and the Epigenetic Alterations in Human Cancers
Authors: Valinluck Victoria , Sowers Lawrence C.
Published: June 2007

Aberrant methylation patterns have long been known to exist in the promoter regions of key regulatory genes in the DNA of tumor cells. However, the mechanisms by which these methylation patterns become altered during the transformation of normal cells to tumor cells have remained elusive. We have recently shown in in vitro studies that inflammation-mediated halogenated cytosine damage products can mimic 5-methylcytosine in directing enzymatic DNA methylation and in enhancing the binding of methyl-binding proteins whereas certain oxidative damage products inhibit both. We have therefore proposed that cytosine damage products could potentially interfere with normal epigenetic control by altering DNA-protein interactions critical for gene regulation and the heritable transmission of methylation patterns. These inflammation-mediated cytosine damage products may provide, in some cases, a mechanistic link between inflammation and cancer. [Cancer Res 2007;67(12):5583–6]
Inactivation of the Wwox Gene Accelerates Forestomach Tumor Progression In vivo
Authors: Aqeilan Rami I. , Hagan John P. , Aqeilan Haifa A. , Pichiorri Flavia , Fong Louise Y.Y. , Croce Carlo M.
Published: June 2007

The WWOX gene encodes a tumor suppressor spanning the second most common human fragile site, FRA16D. Targeted deletion of the Wwox gene in mice led to an increased incidence of spontaneous and ethyl nitrosourea–induced tumors. In humans, loss of heterozygosity and reduced or loss of WWOX expression has been reported in esophageal squamous cell cancers (SCC). In the present study, we examined whether inactivation of the Wwox gene might lead to enhanced esophageal/forestomach tumorigenesis induced by N-nitrosomethylbenzylamine. Wwox+/− and Wwox+/+ mice were treated with six intragastric doses of N-nitrosomethylbenzylamine and observed for 15 subsequent weeks. Ninety-six percent (25 of 26) of Wwox+/− mice versus 29% (10 of 34) of Wwox+/+ mice developed forestomach tumors (P = 1.3 × 10−7). The number of tumors per forestomach was significantly greater in Wwox+/− than in Wwox+/+ mice (3.2 ± 0.34 versus 0.47 ± 0.17; P < 0.0001). In addition, 27% of Wwox+/− mice had invasive SCC in the forestomach, as compared with 0% of wild-type controls (P = 0.002). Intriguingly, forestomachs from Wwox+/− mice displayed moderately strong Wwox protein staining in the near-normal epithelium, but weak and diffuse staining in SCC in the same tissue section, a result suggesting that Wwox was haploinsufficient for the initiation of tumor development. Our findings provide the first in vivo evidence of the tumor suppressor function of WWOX in forestomach/esophageal carcinogenesis and suggest that inactivation of one allele of WWOX accelerates the predisposition of normal cells to malignant transformation. [Cancer Res 2007;67(12):5606– 10]
Nucleotide Excision Repair Pathway Genes and Oral Premalignant Lesions
Authors: Wang Yunfei , Spitz Margaret R. , Lee J. Jack , Huang Maosheng , Lippman Scott M. , Wu Xifeng
Published: June 2007

Purpose: Oral premalignant lesions (OPL) are associated with tobacco exposure and an increase in risk of oral cancer. Nucleotide excision repair (NER) is one of the major DNA repair pathways involved in the removal of tobacco carcinogen adducts. Polymorphisms in NER genes may cause variations in DNA repair capacity and increase susceptibility to both premalignant lesions and cancer.

Experimental Design: In this case-control study of 144 OPL patients and 288 controls, we genotyped 11 polymorphisms in 8 major NER genes, including XPA [A23G at 5′ untranslated region (UTR)], XPD (Asp312Asn, Lys751Gln), XPC (Ala499Val, Lys939Gln), XPG (His1104Asp), XPF (Pro662Ser), ERCC6 (Met1097Val, Arg1230Pro) Rad23B (Ala249Val), and CCNH (Val270Ala).

Results: We found significant or borderline-significant associations between OPL risk and the polymorphisms XPA (A23G), XPD (Lys751Gln), XPC (Ala499Val), Rad23B (Ala249Val), and XPD (Asp312Asn), with adjusted odds ratios (ORs) of 1.97 [95% confidence interval (95% CI), 1.27-3.06], 1.60 (95% CI, 1.02-2.51), 0.63 (95% CI, 0.40-1.00), 0.67 (95% CI, 0.41-1.07), and 1.42 (95% CI, 0.90-2.23), respectively. When further stratified analyses were done, the decreased risk conferred by the XPC (Ala499Val) variant allele was more evident in older individuals (OR, 0.50; 95% CI, 0.24-1.03), in women (OR, 0.46; 95% CI, 0.21-1.01), in ever smokers (OR, 0.59; 95% CI, 0.33-1.05), and in never drinkers (OR, 0.42; 95% CI, 0.18-1.00). Finally, we found joint effects between these NER gene variants and smoking status. For example, when never smokers with the XPA 23A genotypes were used as the reference group, the ORs for never smokers with the XPA 23G genotype, smokers with the 23A genotype, and smokers with 23G genotypes were 2.19 (1.07-4.46), 2.64 (1.42-4.89), and 5.04 (2.62-9.69), respectively. Gene-gene and gene-smoking interaction for OPLs risk were also confirmed by multifactor dimensionality reduction (MDR) analysis in our study. MDR analysis revealed that a model containing ever smoking, XPA (A23G), XPC (Ala499Val), and XPD (Asp312Asn) was the best model to predict OPL risk with maximum average cross-validation consistency and minimum prediction error (P < 0.001).

Conclusion: Our results suggest that polymorphisms in NER genes may contribute to genetic susceptibility to OPLs and may therefore contribute to the development of oral cancer.
Human Leukocyte Antigen Class I Antigen Expression Is an Independent Prognostic Factor in Ovarian Cancer
Authors: Rolland Phil , Deen Suha , Scott Ian , Durrant Lindy , Spendlove Ian
Published: June 2007

Purpose: Despite improvements in cancer treatment, the prognosis of ovarian cancer remains low and imperfectly predicted by traditional pathologic criteria. Biomarkers that predict prognosis independently of such criteria shed light on important molecular variations, aiding in the development and targeting of novel therapies. Previous work has shown human leukocyte antigen (HLA) class I antigen expression to be independently predictive of prognosis in colorectal and breast cancer. We investigated the prognostic potential of HLA class I antigen expression by studying a large series of ovarian cancers.

Experimental Design: A tissue microarray of 339 ovarian cancer cases linked to prospectively recorded clinicopathologic and follow-up data was constructed. This was stained following a standard immunohistochemical protocol for HLA class I heavy chain (HC-10) and β2-microglobulin (β2-m). HLA class I antigen expression was compared with clinicopathologic factors and overall disease-specific survival using the Pearson χ2 test, Kaplan-Meier curves, and the log-rank test. Cox regression was used to test for the independence and magnitude of effects.

Results: There were no univariate correlations between HLA class I antigen expression and clinicopathologic factors. Deviation from an HC-10+/β2-m+ phenotype correlated with reduced survival in univariate analysis (log-rank, 5.69; P = 0.017); a retained HC-10+/β2-m+ phenotype predicted improved prognosis independently of age, stage, level of cytoreduction, and chemotherapy usage on multivariate analysis (hazard ratio, 0.587; 95% confidence interval, 0.442-0.781; P < 0.001).

Conclusions: HLA class I antigen expression is an independent prognostic marker in ovarian cancer, its loss correlating with a poor prognostic outcome.
Treatment of Single Brain Metastasis with Resection, Intracavity Carmustine Polymer Wafers, and Radiation Therapy Is Safe and Provides Excellent Local Control
Authors: Ewend Matthew G. , Brem Steven , Gilbert Mark , Goodkin Robert , Penar Paul L. , Varia Mahesh , Cush Sharon , Carey Lisa A.
Published: June 2007

Purpose: To define the safety and efficacy of carmustine polymer wafers when added to a regimen of surgery and external beam radiotherapy for treatment of a single brain metastasis.

Experimental Design: Adult patients underwent craniotomy for a single brain metastasis, and carmustine polymer wafers were placed in the tumor resection cavity. Patients then received whole-brain radiotherapy and were followed for patterns of recurrence in the central nervous system, toxicity, and survival.

Results: We enrolled 25 patients with solitary brain metastases from lung (13 patients), melanoma (4 patients), breast (3 patients), and renal carcinoma (3 patients). Two patients had severe adverse events thought to be related to wafer placement, one with seizures alone, and one with seizures and subsequent respiratory compromise. Both responded to medical therapy. There were no wound infections. The local recurrence rate was surprisingly low (0%). Four patients (16%) relapsed elsewhere in the brain, and two patients (8%) relapsed in the spinal cord. Median survival was 33 weeks; 33% of patients survived 1 year, and 25% survived 2 years.

Conclusions: The addition of local chemotherapy delivered via carmustine polymer wafers to a regimen of surgical resection and external beam radiotherapy was well tolerated by patients undergoing surgery for a single brain metastasis. There were no local recurrences, suggesting that this treatment further reduced the risk of local relapse.
Cytochrome P450 1B1 Expression in Glial Cell Tumors: An Immunotherapeutic Target
Authors: Barnett Julia A. , Urbauer Diana L. , Murray Graeme I. , Fuller Gregory N. , Heimberger Amy B.
Published: June 2007

Purpose: Among central nervous system malignancies, cytochrome P450 1B1 (CYP1B1) expression has only been characterized in medulloblastoma. An immunotherapeutic agent targeting this antigen was shown to safely stimulate a good immune response. To evaluate the viability of further research efforts targeting this antigen, we examined the expression of CYP1B1 in glial cell malignancies.

Experimental Design: We studied the frequency and extent of CYP1B1 expression by immunohistochemical analysis in 269 glial tumors (including all major pathologic types) on a tissue microarray. Results were categorized by percentage of cells stained and intensity of cytoplasmic staining within cells. Correlation of CYP1B1 expression with patient prognosis was evaluated by univariate and multivariate analyses.

Results: Overall, increased CYP1B1 expression in glial tumors was associated with decreased patient survival time (P < 0.0014 for both percentage and intensity of staining). A significant difference existed in percentage and intensity of staining between astrocytic and oligodendroglial tumors (P = 0.0002 and 0.0003, respectively), between grades of tumors (P < 0.0001 and 0.0079), and between pathologic types of tumors (P < 0.0001 and 0.0339). Positive CYP1B1 staining was seen in 81% of glioblastomas, 84% of anaplastic astrocytomas, 61% of oligodendrogliomas, and 67% of anaplastic oligodendrogliomas. Paradoxically, within specific tumor pathologies, there was a trend toward increased survival as CYP1B1 expression increased. However, in the multivariate analysis, this trend disappeared, and CYP1B1 expression seemed prognostically neutral.

Conclusion: CYP1B1 is frequently expressed in a variety of gliomas and could be used as a target for immunotherapy.
Epidermal Growth Factor Receptor R497K Polymorphism Is a Favorable Prognostic Factor for Patients with Colorectal Carcinoma
Authors: Wang Wei-Shu , Chen Po-Min , Chiou Tzeon-Jye , Liu Jin-Hwang , Lin Jen-Kou , Lin Tzu-Chen , Wang Huann-Sheng , Su Yeu
Published: June 2007

Purpose: It has been shown that the R497K polymorphism of the epidermal growth factor receptor (EGFR) has attenuated functions in ligand binding, tyrosine kinase activation, and growth stimulation. Because the activation of EGFR results in an unfavorable prognosis of patients with colorectal carcinoma, a pilot study was conducted to assess the influence of this polymorphism on colorectal carcinoma patients.

Experimental Design: We retrospectively analyzed the effect of the R497K polymorphism of EGFR on clinicopathologic features in 209 colorectal carcinoma patients, including 100 with stage II/III colorectal carcinoma receiving curative surgery and the other 109 with metastatic diseases.

Results: An excellent correlation in codon 497 statuses examined by patients' WBCs and tumor tissues was found but no significant between-group difference in patients with or without colorectal carcinoma (P = 0.97). A marked decrease on EGFR phosphorylation (P < 0.01) and c-Myc activation (P = 0.02) was observed in patients with R497K polymorphism, which is associated with decreased invasion (P = 0.01), lower nodal involvement (P = 0.02), reduced subsequent metastasis (P < 0.01), and longer disease-free (P < 0.01) as well as overall (P < 0.01) survival in stage II/III colorectal carcinoma patients who had received curative surgery. For patients with metastatic colorectal carcinoma, this polymorphism was associated with a higher response to 5-fluorouracil/oxaliplatin treatment (P = 0.02) and a longer survival (P < 0.01). By multivariate analysis, this polymorphism was also identified as an independent prognostic factor (P = 0.03).

Conclusions: These data suggest that the R497K polymorphism of the EGFR, by reducing its activation and a consequential down-regulation of its target genes, could be a key determinant for reduced tumor recurrence of stage II/III colorectal carcinoma patients receiving curative surgery and a longer survival of patients with stage II/III as well as metastatic colorectal carcinoma.
Promoter Hypermethylation of the Bone Morphogenetic Protein-6 Gene in Malignant Lymphoma
Authors: Daibata Masanori , Nemoto Yuiko , Bandobashi Kentaro , Kotani Norihiro , Kuroda Masayuki , Tsuchiya Mutsumi , Okuda Heiwa , Takakuwa Tetsuya , Imai Shosuke , Shuin Taro , Taguchi Hirokuni
Published: June 2007

Purpose: Bone morphogenetic proteins (BMP), belonging to the transforming growth factor-β superfamily, are important regulators of cell growth, differentiation, and apoptosis. The biological effects of BMPs on malignant lymphoma, however, remain unknown. Promoter methylation of the BMP-6 gene in lymphomas was investigated.

Experimental Design: We investigated BMP-6 promoter methylation and its gene expression in various histologic types of 90 primary lymphomas and 30 lymphoma cell lines. The effect of BMP-6 promoter hypermethylation on clinical outcome was also evaluated.

Results: BMP-6 was epigenetically inactivated in subsets of lymphomas. The silencing occurred with high frequency in diffuse large B-cell lymphoma (DLBCL) and Burkitt's lymphoma in association with aberrant BMP-6 promoter methylation. The methylation was observed in 60% (21 of 35) of DLBCL cases and 100% (7 of 7) of DLBCL cell lines, and in 83% (5 of 6) of Burkitt's lymphoma cases and 86% (12 of 14) of Burkitt's lymphoma cell lines. In contrast, other histologic types of primary lymphomas studied had little or no detectable methylation (1 of 49; 2%). The presence of BMP-6 promoter hypermethylation in DLBCL statistically correlated with a decrease in disease-free survival (P = 0.014) and overall survival (P = 0.038). Multivariate analysis showed that the methylation profile was an independent prognostic factor in predicting disease-free survival (P = 0.022) and overall survival (P = 0. 046).

Conclusion: BMP-6 promoter was hypermethylated more often in aggressive types of lymphomas, and the hypermethylation is likely to be related to the histologic type of lymphomas. BMP-6 promoter methylation may be a potential new biomarker of risk prediction in DLBCL.
Expression of Erythropoietin Receptor andIn vitroFunctional Effects of Epoetins in B-Cell Malignancies
Authors: Kokhaei Parviz , Abdalla Amir Osman , Hansson Lotta , Mikaelsson Eva , Kubbies Manfred , Haselbeck Anton , Jernberg-Wiklund Helena , Mellstedt Håkan , Österborg Anders
Published: June 2007

Purpose: Erythropoietin (EPO) and EPO receptor (EPO-R) expression have been reported in solid tumors and are claimed to regulate tumor growth; however, no data have been published on this issue in B-cell malignancies or normal lymphoid cells. This report describes genomic/protein EPO-R expression and in vitro effects of recombinant human EPO (epoetin) in B-cell chronic lymphocytic leukemia (B-CLL), mantle-cell lymphoma (MCL), and multiple myeloma (MM).

Experimental Design: Blood samples were obtained from patients with B-CLL, MCL, and healthy volunteers, and bone marrow was obtained from MM patients. EPO-R mRNA was detected by reverse transcription-PCR. EPO-R surface expression was investigated by flow cytometry using digoxigenin-labeled epoetin and polyclonal rabbit anti–EPO-R antibody for intracellular receptor. Tumor cell stimulation was determined in vitro using [3H]thymidine incorporation and CD69 expression after exposure to epoetin α or β or darbepoetin α.

Results: EPO-R mRNA was detected in mononuclear cells from 32 of 41 (78%) B-CLL and 5 of 7 (71%) MCL patients, and 21 of 21 (100%) MM samples. Expression was also detected in highly purified T cells from six of eight B-CLL patients, four of four MM patients, and normal donor B and T cells. Surface EPO-R protein was not detected. Intracellular EPO-R staining with anti–EPO-R antibodies was unspecific. No tumor-stimulatory effect was observed with high epoetin concentrations.

Conclusions: EPO-R gene is frequently expressed in lymphoid malignancies and normal B and T cells. However, there was no surface protein expression and no epoetin-induced in vitro stimulation of tumor B cells, indicating that epoetin therapy in vivo is likely to be safe in patients with lymphoid malignancies.