bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Merlin Is a Potent Inhibitor of Glioma Growth
Authors: Lau Ying-Ka Ingar , Murray Lucas B. , Houshmandi Sean S. , Xu Yin , Gutmann David H. , Yu Qin
Published: March 2024

Abstract
Neurofibromatosis 2 (NF2) is an inherited cancer syndrome in which affected individuals develop nervous system tumors, including schwannomas, meningiomas, and ependymomas. The NF2 protein merlin (or schwannomin) is a member of the Band 4.1 superfamily of proteins, which serve as linkers between transmembrane proteins and the actin cytoskeleton. In addition to mutational inactivation of the NF2 gene in NF2-associated tumors, mutations and loss of merlin expression have also been reported in other types of cancers. In the present study, we show that merlin expression is dramatically reduced in human malignant gliomas and that reexpression of functional merlin dramatically inhibits both subcutaneous and intracranial growth of human glioma cells in mice. We further show that merlin reexpression inhibits glioma cell proliferation and promotes apoptosis in vivo. Using microarray analysis, we identify altered expression of specific molecules that play key roles in cell proliferation, survival, and motility. These merlin-induced changes of gene expression were confirmed by real-time quantitative PCR, Western blotting, and functional assays. These results indicate that reexpression of merlin correlates with activation of mammalian sterile 20-like 1/2–large tumor suppressor 2 signaling pathway and inhibition of canonical and noncanonical Wnt signals. Collectively, our results show that merlin is a potent inhibitor of high-grade human glioma. [Cancer Res 2008;68(14):5733–42]
Data from Inhibition of Metastatic Outgrowth from Single Dormant Tumor Cells by Targeting the Cytoskeleton
Authors: Barkan Dalit , Kleinman Hynda , Simmons Justin L. , Asmussen Holly , Kamaraju Anil K. , Hoenorhoff Mark J. , Liu Zi-yao , Costes Sylvain V. , Cho Edward H. , Lockett Stephen , Khanna Chand , Chambers Ann F. , Green Jeffrey E.
Published: March 2024

Abstract
Metastatic breast cancer may emerge from latent tumor cells that remain dormant at disseminated sites for many years. Identifying mechanisms regulating the switch from dormancy to proliferative metastatic growth has been elusive due to the lack of experimental models of tumor cell dormancy. We characterized the in vitro growth characteristics of cells that exhibit either dormant (D2.0R, MCF-7, and K7M2AS1.46) or proliferative (D2A1, MDA-MB-231, and K7M2) metastatic behavior in vivo. Although these cells proliferate readily in two-dimensional culture, we show that when grown in three-dimensional matrix, distinct growth properties of the cells were revealed that correlate to their dormant or proliferative behavior at metastatic sites in vivo. In three-dimensional culture, cells with dormant behavior in vivo remained cell cycle arrested with elevated nuclear expression of p16 and p27. The transition from quiescence to proliferation of D2A1 cells was dependent on fibronectin production and signaling through integrin β1, leading to cytoskeletal reorganization with filamentous actin (F-actin) stress fiber formation. We show that phosphorylation of myosin light chain (MLC) by MLC kinase (MLCK) through integrin β1 is required for actin stress fiber formation and proliferative growth. Inhibition of integrin β1 or MLCK prevents transition from a quiescent to proliferative state in vitro. Inhibition of MLCK significantly reduces metastatic outgrowth in vivo. These studies show that the switch from dormancy to metastatic growth may be regulated, in part, through epigenetic signaling from the microenvironment, leading to changes in the cytoskeletal architecture of dormant cells. Targeting this process may provide therapeutic strategies for inhibition of the dormant-to-proliferative metastatic switch. [Cancer Res 2008;68(15):6241–50]
Data from Altered TAB1:IκB Kinase Interaction Promotes Transforming Growth Factor β–Mediated Nuclear Factor-κB Activation during Breast Cancer Progression
Authors: Neil Jason R. , Schiemann William P.
Published: March 2024

Abstract
The conversion of transforming growth factor β (TGF-β) from a tumor suppressor to a tumor promoter occurs frequently during mammary tumorigenesis, yet the molecular mechanisms underlying this phenomenon remain undefined. We show herein that TGF-β repressed nuclear factor-κB (NF-κB) activity in normal NMuMG cells, but activated this transcription factor in their malignant counterparts, 4T1 cells, by inducing assembly of TGF-β–activated kinase 1 (TAK1)–binding protein 1 (TAB1):IκB kinase β (IKKβ) complexes, which led to the stimulation of a TAK1:IKKβ:p65 pathway. TAB1:IKKβ complexes could only be detected in NMuMG cells following their induction of epithelial-mesenchymal transition (EMT), which, on TGF-β treatment, activated NF-κB. Expression of a truncated TAB1 mutant [i.e., TAB1(411)] reduced basal and TGF-β–mediated NF-κB activation in NMuMG cells driven to undergo EMT by TGF-β and in 4T1 cells stimulated by TGF-β. TAB1(411) expression also inhibited TGF-β–stimulated tumor necrosis factor-α and cyclooxygenase-2 expression in 4T1 cells. Additionally, the ability of human MCF10A-CA1a breast cancer cells to undergo invasion in response to TGF-β absolutely required the activities of TAK1 and NF-κB. Moreover, small interfering RNA–mediated TAK1 deficiency restored the cytostatic activity of TGF-β in MCF10A-CA1a cells. Finally, expression of truncated TAB1(411) dramatically reduced the growth of 4T1 breast cancers in syngeneic BALB/c, as well as in nude mice, suggesting a potentially important role of NF-κB in regulating innate immunity by TGF-β. Collectively, our findings have defined a novel TAB1:TAK1:IKKβ:NF-κB signaling axis that forms aberrantly in breast cancer cells and, consequently, enables oncogenic signaling by TGF-β. [Cancer Res 2008;68(5):1462–70]
Data from Genomic Profiling of MicroRNA and Messenger RNA Reveals Deregulated MicroRNA Expression in Prostate Cancer
Authors: Ambs Stefan , Prueitt Robyn L. , Yi Ming , Hudson Robert S. , Howe Tiffany M. , Petrocca Fabio , Wallace Tiffany A. , Liu Chang-Gong , Volinia Stefano , Calin George A. , Yfantis Harris G. , Stephens Robert M. , Croce Carlo M.
Published: March 2024

Abstract
MicroRNAs are small noncoding RNAs that regulate the expression of protein-coding genes. To evaluate the involvement of microRNAs in prostate cancer, we determined genome-wide expression of microRNAs and mRNAs in 60 primary prostate tumors and 16 nontumor prostate tissues. The mRNA analysis revealed that key components of microRNA processing and several microRNA host genes, e.g., MCM7 and C9orf5, were significantly up-regulated in prostate tumors. Consistent with these findings, tumors expressed the miR-106b-25 cluster, which maps to intron 13 of MCM7, and miR-32, which maps to intron 14 of C9orf5, at significantly higher levels than nontumor prostate. The expression levels of other microRNAs, including a number of miR-106b-25 cluster homologues, were also altered in prostate tumors. Additional differences in microRNA abundance were found between organ-confined tumors and those with extraprostatic disease extension. Lastly, we found evidence that some microRNAs are androgen-regulated and that tumor microRNAs influence transcript abundance of protein-coding target genes in the cancerous prostate. In cell culture, E2F1 and p21/WAF1 were identified as targets of miR-106b, Bim of miR-32, and exportin-6 and protein tyrosine kinase 9 of miR-1. In summary, microRNA expression becomes altered with the development and progression of prostate cancer. Some of these microRNAs regulate the expression of cancer-related genes in prostate cancer cells. [Cancer Res 2008;68(15):6162–70]
Data from DNA Damage–Dependent Translocation of B23 and p19ARF Is Regulated by the Jun N-Terminal Kinase Pathway
Authors: Yogev Orli , Saadon Keren , Anzi Shira , Inoue Kazushi , Shaulian Eitan
Published: March 2024

Abstract
The dynamic behavior of the nucleolus plays a role in the detection of and response to DNA damage of cells. Two nucleolar proteins, p14ARF/p19ARF and B23, were shown to translocate out of the nucleolus after exposure of cells to DNA-damaging agents. This translocation affects multiple cellular functions, such as DNA repair, proliferation, and survival. In this study, we identify a pathway and scrutinize the mechanisms leading to the translocation of these proteins after exposure of cells to DNA-damaging agents. We show that redistribution of B23 and p19ARF after the exposure to genotoxic stress occurs preferentially when the c-Jun-NH2-kinase (JNK) pathway is activated and is inhibited when the JNK pathway is impaired. The stress-induced translocation of alternative reading frame (ARF) is JNK dependent and mediated by two activator proteins, c-Jun and JunB. Thr91 and Thr93 of c-Jun are required for the translocation, but the transcriptional activity of c-Jun is dispensable. Instead, c-Jun interacts with B23 in a dose-dependent manner. c-Jun itself is excluded from the nucleolus in a JNK-dependent manner. Hence, we suggest that c-Jun translocates B23 and ARF from the nucleolus after JNK activation by means of protein interactions. In senescent cells, JNK activity and c-Jun levels are reduced concomitantly with ARF nucleolar accumulation, and UV radiation does not cause the translocation of ARF. [Cancer Res 2008;68(5):1398–406]
Data from Regulation of Id1 Expression by Src: Implications for Targeting of the Bone Morphogenetic Protein Pathway in Cancer
Authors: Gautschi Oliver , Tepper Clifford G. , Purnell Phillip R. , Izumiya Yoshihiro , Evans Christopher P. , Green Tim P. , Desprez Pierre Y. , Lara Primo N. , Gandara David R. , Mack Philip C. , Kung Hsing-Jien
Published: March 2024

Abstract
Deregulated activation of the Src tyrosine kinase and heightened Id1 expression are independent mediators of aggressive tumor biology. The present report implicates Src signaling as a critical regulator of Id1 gene expression. Microarray analyses showed that Id family genes were among the most highly down-regulated by incubation of A549 lung carcinoma cells with the small-molecule Src inhibitor AZD0530. Id1 transcript and protein levels were potently reduced in a dose-dependent manner concomitantly with the reduction of activated Src levels. These effects were conserved across a panel of lung, breast, prostate, and colon cancer cell lines and confirmed by the ability of PP2, Src siRNA, and Src-blocking peptides to suppress Id1 expression. PP2, AZD0530, and dominant-negative Src abrogated Id1 promoter activity, which was induced by constitutively active Src. The Src-responsive region of the Id1 promoter was mapped to a region 1,199 to 1,360 bps upstream of the translation start site and contained a Smad-binding element. Src was also required for bone morphogenetic protein-2 (BMP-2)–induced Id1 expression and promoter activity, was moderately activated by BMP-2, and complexed with Smad1/5. Conversely, Src inhibitors blocked Smad1/5 nuclear translocation and binding to the Src-responsive region of the Id1 promoter. Consistent with a role for Src and Id1 in cancer cell invasion, Src inhibitors and Id1 siRNA decreased cancer cell invasion, which was increased by Id1 overexpression. Taken together, these results reveal that Src positively interacts with the BMP-Smad-Id pathway and provide new ways for targeted inhibition of Id1. [Cancer Res 2008;68(7):2250–8]
Data from Flt-1 Signaling in Macrophages Promotes Glioma Growth In vivo
Authors: Kerber Mark , Reiss Yvonne , Wickersheim Anke , Jugold Manfred , Kiessling Fabian , Heil Matthias , Tchaikovski Vadim , Waltenberger Johannes , Shibuya Masabumi , Plate Karl H. , Machein Marcia Regina
Published: March 2024

Abstract
Several lines of evidence indicate that Flt-1, a fms-like tyrosine kinase receptor, which binds to vascular endothelial growth factor (VEGF)-A, VEGF-B, and PlGF, is a positive regulator of angiogenesis in the context of tumor growth and metastasis. However, the molecular basis of its action is still not clear. Besides endothelial cells, Flt-1 is also expressed by other different cell types, including myeloid hematopoeitic cells (monocytes and macrophages). To examine the functions of Flt-1 expressed by bone marrow–derived myeloid cells in supporting tumor growth and angiogenesis, Flt-1 tyrosine kinase–deficient (Flt-1 TK−/−) bone marrow cells were transplanted into lethally irradiated syngeneic recipients. After hematopoietic reconstitution, we orthotopically implanted syngeneic wild-type glioma cells or glioma cells overexpressing either VEGF164 or PlGF-2. Loss of Flt-1 signaling in bone marrow–derived myeloid cells led to a significant decrease in tumor volume and vascularization in gliomas. VEGF but not PlGF overexpressed by glioma cells restored the tumor growth rate in Flt-1 TK−/− bone marrow chimera. VEGF and PlGF overexpression by tumor cells induced an accumulation of bone marrow–derived myeloid cells into tumor tissue. This infiltration was decreased in tumors grown in Flt-1 TK−/− bone marrow chimeras. When investigating chemokines and growth factors involved in myeloid cell recruitment, we determined elevated SDF-1/CXCL12 levels in VEGF- and PlGF-overexpressing tumors. Collectively, these results suggest that Flt-1 signaling in myeloid cells is essential to amplify the angiogenic response and to promote glioma growth. [Cancer Res 2008;68(18):7342–51]
Data from A Novel RET Kinase–β-Catenin Signaling Pathway Contributes to Tumorigenesis in Thyroid Carcinoma
Authors: Gujral Taranjit S. , van Veelen Wendy , Richardson Douglas S. , Myers Shirley M. , Meens Jalna A. , Acton Dennis S. , Duñach Mireia , Elliott Bruce E. , Höppener Jo W.M. , Mulligan Lois M.
Published: March 2024

Abstract
The RET receptor tyrosine kinase has essential roles in cell survival, differentiation, and proliferation. Oncogenic activation of RET causes the cancer syndrome multiple endocrine neoplasia type 2 (MEN 2) and is a frequent event in sporadic thyroid carcinomas. However, the molecular mechanisms underlying RET's potent transforming and mitogenic signals are still not clear. Here, we show that nuclear localization of β-catenin is frequent in both thyroid tumors and their metastases from MEN 2 patients, suggesting a novel mechanism of RET-mediated function through the β-catenin signaling pathway. We show that RET binds to, and tyrosine phosphorylates, β-catenin and show that the interaction between RET and β-catenin can be direct and independent of cytoplasmic kinases, such as SRC. As a result of RET-mediated tyrosine phosphorylation, β-catenin escapes cytosolic down-regulation by the adenomatous polyposis coli/Axin/glycogen synthase kinase-3 complex and accumulates in the nucleus, where it can stimulate β-catenin–specific transcriptional programs in a RET-dependent fashion. We show that down-regulation of β-catenin activity decreases RET-mediated cell proliferation, colony formation, and tumor growth in nude mice. Together, our data show that a β-catenin–RET kinase pathway is a critical contributor to the development and metastasis of human thyroid carcinoma. [Cancer Res 2008;68(5):1338–46]
Data from Breast Cancer Risk Reduction and Membrane-Bound Catechol O-Methyltransferase Genetic Polymorphisms
Authors: Ji Yuan , Olson Janet , Zhang Jianping , Hildebrandt Michelle , Wang Liewei , Ingle James , Fredericksen Zachary , Sellers Thomas , Miller William , Dixon J. Michael , Brauch Hiltrud , Eichelbaum Michel , Justenhoven Christina , Hamann Ute , Ko Yon , Brüning Thomas , Chang-Claude Jenny , Wang-Gohrke Shan , Schaid Daniel , Weinshilboum Richard
Published: March 2024

Abstract
Catechol O-methyltransferase (COMT)-catalyzed methylation of catecholestrogens has been proposed to play a protective role in estrogen-induced genotoxic carcinogenesis. We have taken a comprehensive approach to test the hypothesis that genetic variation in COMT might influence breast cancer risk. Fifteen COMT single nucleotide polymorphisms (SNPs) selected on the basis of in-depth resequencing of the COMT gene were genotyped in 1,482 DNA samples from a Mayo Clinic breast cancer case control study. Two common SNPs in the distal promoter for membrane-bound (MB) COMT, rs2020917 and rs737865, were associated with breast cancer risk reduction in premenopausal women in the Mayo Clinic study, with allele-specific odds ratios (OR) of 0.70 [95% confidence interval (CI), 0.52–0.95] and 0.68 (95% CI, 0.51–0.92), respectively. These two SNPs were then subjected to functional genomic analysis and were genotyped in an additional 3,683 DNA samples from two independent case control studies (GENICA and GESBC). Functional genomic experiments showed that these SNPs could up-regulate transcription and that they altered DNA-protein binding patterns. Furthermore, substrate kinetic and exon array analyses suggested a role for MB-COMT in catecholestrogen inactivation. The GENICA results were similar to the Mayo case control observations, with ORs of 0.85 (95% CI, 0.72–1.00) and 0.85 (95% CI, 0.72–1.01) for the two SNPs. No significant effect was observed in the GESBC study. These studies showed that two SNPs in the COMT distal promoter were associated with breast cancer risk reduction in two of three case control studies, compatible with the results of functional genomic experiments, suggesting a role for MB-COMT in breast cancer risk. [Cancer Res 2008;68(14):5997–6005]
Data from Hypoxia-Inducible Factor-1 Target Genes as Indicators of Tumor Vessel Response to Vascular Endothelial Growth Factor Inhibition
Authors: Dang Duyen T. , Chun Sang Y. , Burkitt Kyunghee , Abe Masako , Chen Shaowei , Havre Pamela , Mabjeesh Nicola J. , Heath Elisabeth I. , Vogelzang Nicholas J. , Cruz-Correa Marcia , Blayney Douglas W. , Ensminger William D. , Croix Brad St. , Dang Nam H. , Dang Long H.
Published: March 2024

Abstract
Antiangiogenic therapy improves survival in patients with advanced stage cancers. Currently, there are no reliable predictors or markers for tumor vessel response to antiangiogenic therapy. To model effective antiangiogenic therapy, we disrupted the VEGF gene in three representative cancer cell lines. HCT116 xenografts had low proportions of endothelial tubes covered by pericytes that stained with α-smooth muscle actin (SMA) antibody. Upon disruption of VEGF, HCT116VEGF−/− xenografts had significantly decreased tumor microvessel perfusion compared with their parental counterparts. Furthermore, HCT116VEGF−/− xenografts mounted a tumor-reactive response to hypoxia, characterized by the induction of hypoxia-inducible factor-1 (HIF-1) target genes. One highly induced protein was DPP4, a measurable serum protein that has well-described roles in cancer progression. In contrast, LS174T and MKN45 tumor xenografts had high proportion of endothelial tubes that were covered by SMA+ pericytes. Upon disruption of VEGF, LS174TVEGF−/− and MKN45VEGF−/− xenografts maintained tumor microvessel perfusion. As such, there were no changes in intratumoral hypoxia or HIF-1α induction. Together, these data show that the extent of tumor vessel response to angiogenic inhibition could be correlated with (a) the preexisting coverage of tumor endothelial tubes with SMA+ pericytes and (b) differential tumor induction of HIF-1 target genes. The data further show that DPP4 is a novel marker of HIF-1 induction. Altogether, these preclinical findings suggest novel clinical trials for predicting and monitoring tumor vessel responses to antiangiogenic therapy. [Cancer Res 2008;68(6):1872–80]
Data from Tumor-Induced Suppressor of Cytokine Signaling 3 Inhibits Toll-like Receptor 3 Signaling in Dendritic Cells via Binding to Tyrosine Kinase 2
Authors: Zeng Bin , Li Haijie , Liu Yu , Zhang Zhuohan , Zhang Yuan , Yang Rongcun
Published: March 2024

Abstract
The suppressor of cytokine signaling (SOCS) family of negative regulatory proteins is up-regulated in response to several cytokines and pathogen-associated molecular patterns (PAMP) and suppresses cellular signaling responses by binding receptor phosphotyrosine residues. Exposure of bone marrow–derived dendritic cells (BMDC) to 1D8 cells, a murine model of ovarian carcinoma, suppresses their ability to express CD40 and stimulate antigen-specific responses in response to PAMPs and, in particular, to polyinosinic acid:poly-CMP (polyI:C) with the up-regulated SOCS3 transcript and protein levels. The ectopic expression of SOCS3 in both the macrophage cell line RAW264.7 and BMDCs decreased signaling in response to both polyI:C and IFNα. Further, knockdown of SOCS3 transcripts significantly enhanced the responses of RAW264.7 and BMDCs to both polyI:C and IFNα. Immunoprecipitation and pull-down studies show that SOCS3 binds to the IFNα receptor tyrosine kinase 2 (TYK2). Because polyI:C triggers autocrine IFNα signaling, binding of SOCS3 to TYK2 may thereby suppress the activation of BMDCs by polyI:C and IFNα. Thus, elevated levels of SOCS3 in tumor-associated DCs may potentially resist the signals induced by Toll-like receptor 3 ligands and type I IFN to decrease DC activation via binding with IFNα receptor TYK2. [Cancer Res 2008;68(13):5397–404]
Data from MUC1 Oncoprotein Blocks Death Receptor–Mediated Apoptosis by Inhibiting Recruitment of Caspase-8
Authors: Agata Naoki , Ahmad Rehan , Kawano Takeshi , Raina Deepak , Kharbanda Surender , Kufe Donald
Published: March 2024

Abstract
Stimulation of the death receptor superfamily induces the activation of caspase-8 and thereby the apoptotic response. The MUC1 oncoprotein is aberrantly overexpressed by diverse human malignancies and inhibits stress-induced apoptosis. The present results show that MUC1 blocks activation of caspase-8 and apoptosis in the response of malignant cells to tumor necrosis factor α, tumor necrosis factor–related apoptosis-inducing ligand, and Fas ligand. The results show that MUC1 associates constitutively with caspase-8. The MUC1 cytoplasmic domain (MUC1-CD) binds directly to the caspase-8 p18 fragment upstream to the catalytic Cys360 site. The results also show that MUC1-CD binds to Fas-associated death domain (FADD) at the death effector domain. In nonmalignant epithelial cells, MUC1 interacts with caspase-8 and FADD as an induced response to death receptor stimulation. The functional significance of these interactions is supported by the demonstration that MUC1 competes with caspase-8 for binding to FADD and blocks recruitment of caspase-8 to the death-inducing signaling complex. These findings indicate that MUC1 is of importance to the physiologic regulation of caspase-8 activity and that overexpression of MUC1, as found in human malignancies, could contribute to constitutive inhibition of death receptor signaling pathways. [Cancer Res 2008;68(15):6136–44]
Data from Systematic High-Content Proteomic Analysis Reveals Substantial Immunologic Changes in Colorectal Cancer
Authors: Berndt Uta , Philipsen Lars , Bartsch Sebastian , Wiedenmann Bertram , Baumgart Daniel C. , Hämmerle Marcus , Sturm Andreas
Published: March 2024

Abstract
The immune system is a significant determinant of epithelial tumorigenesis, but its role in colorectal cancer pathogenesis is not well understood. The function of the immune system depends upon the integrity of the protein network environment, and thus, we performed MELC immunofluorescence microscopy focusing on the lamina propria. By analyzing structurally intact tissues from colorectal cancer, ulcerative colitis, and healthy colonic mucosa, we used this unique and novel highly multiplexed robotic-imaging technology, which allows visualizing dozens of proteins simultaneously, and explored the toponome in colorectal cancer mucosa for the first time. We identified 1,930 motifs that distinguish control from colorectal cancer tissue. In colorectal cancer, the number of activated T cells is increased, explained by a lack of bax, caspase-3, and caspase-8. Whereas CD4+CD25+ T cells are decreased and are, other than in ulcerative colitis, not activated, cytotoxic T cells are significantly increased in colorectal cancer. Furthermore, the number of activated human lymphocyte antigen (HLA)-DR+ T-cells is increased in colorectal cancer, pointing to an altered antigen presentation. In colorectal cancer, CD3+CD29+ expression and assembly of the LFA-1 and LFA-3 receptor are differentially changed, indicating a distinct regulation of T-cell adhesion in colorectal cancer. We also identified increased numbers of natural killer and CD44+ cells in the colorectal cancer mucosa and nuclear factor-κB as regulator of apoptosis in these cell populations. High-content proteomic analysis showed that colorectal cancer induces a tremendous modification of protein expression profiles in the lamina propria. Thus, topological proteomic analysis may help to unravel the role of the adaptive immune system in colorectal cancer and aid the development of new antitumor immunotherapy approaches. [Cancer Res 2008;68(3):880–8]
Data from Oxidative Stress Plays a Critical Role in Inactivating Mutant BRAF by Geldanamycin Derivatives
Authors: Fukuyo Yayoi , Inoue Masahiro , Nakajima Takuma , Higashikubo Ryuji , Horikoshi Nobuko T. , Hunt Clayton , Usheva Anny , Freeman Michael L. , Horikoshi Nobuo
Published: March 2024

Abstract
The geldanamycin derivatives 17-allylamino-17-demethoxygeldanamycin (17-AAG) and 17-dimethylaminoethylamino-17-demethoxygeldanamycin (17-DMAG) are promising chemotherapeutic drugs that inhibit heat shock protein 90 (HSP90) function. Previous studies have shown that 17-AAG/DMAG treatment induces the degradation of mutant BRAF (V600E) and inhibits the activation of mitogen-activated protein/extracellular signal-regulated kinase 1/2 (MEK1/2). We have found, however, that HSP90 inhibition alone is not sufficient for efficient BRAF(V600E) degradation in some cells. HSP90 inhibitors structurally unrelated to geldanamycin, radicicol and novobiocin, while inducing the degradation of the HSP90 client protein RAF-1 fail to induce BRAF(V600E) degradation or inhibit MEK1/2 activation in HT29 human colon cancer cells. Moreover, after treatment with 17-DMAG, the kinase activity of residual, undegraded BRAF(V600E) was also lost. Incubation of cells with a reactive oxygen species (ROS) scavenger, N-acetyl cysteine, partially restored kinase activity and also partially prevented BRAF(V600E) degradation due to 17-DMAG treatment. Conversely, treatment with the ROS producing drug menadione clearly inhibited MEK1/2 and reduced BRAF(V600E). These results suggest that in addition to direct inhibition of HSP90, the antitumor effect of geldanamycin and its derivatives is also mediated though the production of ROS, which may directly inactivate tumorigenic mutant BRAF(V600E). [Cancer Res 2008;68(15):6324–30]
Data from Sixteen–Kinase Gene Expression Identifies Luminal Breast Cancers with Poor Prognosis
Authors: Finetti Pascal , Cervera Nathalie , Charafe-Jauffret Emmanuelle , Chabannon Christian , Charpin Colette , Chaffanet Max , Jacquemier Jocelyne , Viens Patrice , Birnbaum Daniel , Bertucci François
Published: March 2024

Abstract
Breast cancer is a heterogeneous disease made of various molecular subtypes with different prognosis. However, evolution remains difficult to predict within some subtypes, such as luminal A, and treatment is not as adapted as it should be. Refinement of prognostic classification and identification of new therapeutic targets are needed. Using oligonucleotide microarrays, we profiled 227 breast cancers. We focused our analysis on two major breast cancer subtypes with opposite prognosis, luminal A (n = 80) and basal (n = 58), and on genes encoding protein kinases. Whole-kinome expression separated luminal A and basal tumors. The expression (measured by a kinase score) of 16 genes encoding serine/threonine kinases involved in mitosis distinguished two subgroups of luminal A tumors: Aa, of good prognosis and Ab, of poor prognosis. This classification and its prognostic effect were validated in 276 luminal A cases from three independent series profiled across different microarray platforms. The classification outperformed the current prognostic factors in univariate and multivariate analyses in both training and validation sets. The luminal Ab subgroup, characterized by high mitotic activity compared with luminal Aa tumors, displayed clinical characteristics and a kinase score intermediate between the luminal Aa subgroup and the luminal B subtype, suggesting a continuum in luminal tumors. Some of the mitotic kinases of the signature represent therapeutic targets under investigation. The identification of luminal A cases of poor prognosis should help select appropriate treatment, whereas the identification of a relevant kinase set provides potential targets. [Cancer Res 2008;68(3):767–76]
Data from Inhibition of Hsp90 Down-regulates Mutant Epidermal Growth Factor Receptor (EGFR) Expression and Sensitizes EGFR Mutant Tumors to Paclitaxel
Authors: Sawai Ayana , Chandarlapaty Sarat , Greulich Heidi , Gonen Mithat , Ye Qing , Arteaga Carlos L. , Sellers William , Rosen Neal , Solit David B.
Published: March 2024

Abstract
Mutations in the kinase domain of the epidermal growth factor receptor (EGFR) are found in a subset of patients with lung cancer and correlate with response to EGFR tyrosine kinase inhibitors (TKI). Resistance to these agents invariably develops, and current treatment strategies have limited efficacy in this setting. Hsp90 inhibitors, such as 17-allylamino-17-demethoxygeldanamycin (17-AAG), induce the degradation of EGFR and other Hsp90 interacting proteins and may thus have utility in tumors dependent upon sensitive Hsp90 clients. We find that the EGFR mutations found most commonly in patients with lung adenocarcinoma who respond to EGFR TKIs are potently degraded by 17-AAG. Although the expression of wild-type EGFR was also down-regulated by 17-AAG, its degradation required higher concentrations of drug and a longer duration of drug exposure. In animal models, a single dose of 17-AAG was sufficient to induce degradation of mutant EGFR and inhibit downstream signaling. 17-AAG treatment, at its maximal tolerated dose, caused a significant delay in H3255 (L858R EGFR) xenograft growth but was less effective than the EGFR TKI gefitinib. 17-AAG alone delayed, but did not completely inhibit, the growth of H1650 and H1975 xenografts, two EGFR mutant models which show intermediate and high levels of gefitinib resistance. 17-AAG could be safely coadministered with paclitaxel, and the combination was significantly more effective than either drug alone. These data suggest that Hsp90 inhibition in combination with chemotherapy may represent an effective treatment strategy for patients whose tumors express EGFR kinase domain mutations, including those with de novo and acquired resistance to EGFR TKIs. [Cancer Res 2008;68(2):589–96]
Data from CX3CR1 Is Expressed by Prostate Epithelial Cells and Androgens Regulate the Levels of CX3CL1/Fractalkine in the Bone Marrow: Potential Role in Prostate Cancer Bone Tropism
Authors: Jamieson Whitney L. , Shimizu Saori , D'Ambrosio Julia A. , Meucci Olimpia , Fatatis Alessandro
Published: March 2024

Abstract
We have previously shown that the chemokine fractalkine promotes the adhesion of human prostate cancer cells to bone marrow endothelial cells as well as their migration toward human osteoblasts in vitro. Thus, the interaction of fractalkine with its receptor CX3CR1 could play a crucial role in vivo by directing circulating prostate cancer cells to the bone. We found that although CX3CR1 is minimally detectable in epithelial cells of normal prostate glands, it is overexpressed upon malignant transformation. Interestingly, osteoblasts, stromal and mesenchymal cells derived from human bone marrow aspirates express the cell-bound form of fractalkine, whereas the soluble form of the chemokine is detected in bone marrow supernatants. To investigate the mechanisms regulating the levels of soluble fractalkine in the bone marrow, we focused on androgens, which play a critical role in both prostate cancer progression and skeletal metastasis. Here, we show that dihydrotestosterone dramatically increases the cleavage of fractalkine from the plasma membrane of bone cells and its action is reversed by nilutamide—an antagonist of the androgen receptor—as well as the wide-spectrum inhibitor of matrix metalloproteases, GM6001. However, dihydrotestosterone was unable to induce fractalkine-cleavage from human bone marrow endothelial cells. Thus, androgens could promote the extravasation of CX3CR1-bearing cancer cells on a fractalkine concentration gradient, while leaving unaltered their ability to adhere to the bone marrow endothelium. In conclusion, our results indicate that CX3CR1, fractalkine, and the enzymes responsible for its cleavage might represent suitable targets for therapies aiming to counteract skeletal secondary tumors from prostate adenocarcinoma. [Cancer Res 2008;68(6):1715–22]
Data from The Regulatory T Cell–Associated Transcription Factor FoxP3 Is Expressed by Tumor Cells
Authors: Ebert Lisa M. , Tan Bee Shin , Browning Judy , Svobodova Suzanne , Russell Sarah E. , Kirkpatrick Naomi , Gedye Craig , Moss Denis , Ng Sweet Ping , MacGregor Duncan , Davis Ian D. , Cebon Jonathan , Chen Weisan
Published: March 2024

Abstract
FoxP3 is a member of the forkhead family of transcription factors critically involved in the development and function of CD25+ regulatory T cells (Treg). Until recently, FoxP3 expression was thought to be restricted to the T-cell lineage. However, using immunohistochemistry and flow cytometric analysis of human melanoma tissue, we detected FoxP3 expression not only in the tumor infiltrating Treg but also in the melanoma cells themselves. FoxP3 is also widely expressed by established human melanoma cell lines (as determined by flow cytometry, PCR, and Western blot), as well as cell lines derived from other solid tumors. Normal B cells do not express FoxP3; however, expression could be induced after transformation with EBV in vitro and in vivo, suggesting that malignant transformation of healthy cells can induce FoxP3. In addition, a FOXP3 mRNA variant lacking exons 3 and 4 was identified in tumor cell lines but was absent from Treg. Interestingly, this alternative splicing event introduces a translation frame-shift that is predicted to encode a novel protein. Together, our results show that FoxP3, a key regulator of immune suppression, is not only expressed by Treg but also by melanoma cells, EBV-transformed B cells, and a wide variety of tumor cell lines. [Cancer Res 2008;68(8):3001–9]
Data from Inflammatory Signaling and Aryl Hydrocarbon Receptor Mediate Synergistic Induction of Interleukin 6 in MCF-7 Cells
Authors: Hollingshead Brett D. , Beischlag Timothy V. , DiNatale Brett C. , Ramadoss Preeti , Perdew Gary H.
Published: March 2024

Abstract
The pleiotropic cytokine interleukin 6 (IL-6) is involved in immune cell homeostasis. Additionally, IL-6 expression and signaling in tumor cells have been shown to elicit both protumor and antitumor properties. There is a plethora of mechanistic knowledge regarding how IL-6 signal transduction translates to biological responses. However, there is little understanding as to what factors control IL-6 expression within a tumor cell environment. The studies presented herein show that, in MCF-7 breast and ECC-1 endocervical cancer cells, the stimulation of aryl hydrocarbon receptor (AHR) activity, in combination with IL-1β or phorbol 12-myristate 13-acetate (PMA) treatment, results in a marked synergistic induction of IL-6 levels over what is seen without AHR activation. Chromatin immunoprecipitation experiments suggest that the regulation of IL-6 mRNA expression occurs at the chromatin level, as AHR presence on the IL-6 promoter was observed in response to treatment with AHR ligand. Synergistic induction of IL-6 expression was sustained for 72 hours, with accumulation of IL-6 protein reaching levels 4.8-fold above IL-1β treatment alone. In addition, transcriptional regulation of the prototypic AHR responsive gene Cyp1a1 was negatively regulated by PMA and IL-1β treatment. Silencing of RELA expression alleviated IL-1β–mediated repression of AHR transcriptional activity, whereas PMA-mediated repression was maintained. Additionally, small interfering RNA studies reveal that AHR and RELA are necessary for synergistic induction of IL-6. The findings presented here reveal the AHR as a potential therapeutic target for selective modulation of IL-6 expression in some tumor cell types. The data also suggest a possible previously unrecognized mechanism of AHR-mediated tumor promotion. [Cancer Res 2008;68(10):3609–17]
Data from A Novel Recurrent Chromosomal Inversion Implicates the Homeobox Gene Dlx5 in T-Cell Lymphomas from Lck-Akt2 Transgenic Mice
Authors: Tan Yinfei , Timakhov Roman A. , Rao Mamta , Altomare Deborah A. , Xu Jinfei , Liu Zemin , Gao Qingshen , Jhanwar Suresh C. , Di Cristofano Antonio , Wiest David L. , Knepper Janice E. , Testa Joseph R.
Published: March 2024

Abstract
The oncogene v-akt was isolated from a retrovirus that induced murine thymic lymphomas. Transgenic mice expressing a constitutively activated form of the cellular homologue Akt2 specifically in immature T cells develop spontaneous thymic lymphomas. We hypothesized that tumors from these mice might exhibit oncogenic chromosomal rearrangements that cooperate with activated Akt2 in lymphomagenesis. Cytogenetic analysis revealed a recurrent clonal inversion of chromosome 6, inv(6), in thymic lymphomas from multiple transgenic founder lines, including one line in which 15 of 15 primary tumors exhibited this same rearrangement. Combined fluorescence in situ hybridization, PCR, and DNA sequence analyses showed that the distal inv(6) breakpoint resides at the T-cell receptor β chain locus, Tcrb. The proximal breakpoint maps to a region near a locus comprising the linked homeobox/transcription factor genes Dlx5 and Dlx6. Expression analysis of genes translocated to the vicinity of the Tcrb enhancer revealed that Dlx5 and Dlx6 are overexpressed in tumors exhibiting the inv(6). Experimental overexpression of Dlx5 in mammalian cells resulted in enhanced cell proliferation and increased colony formation, and clonogenic assays revealed cooperativity when both Dlx5 and activated Akt2 were coexpressed. In addition, DLX5, but not DLX6, was found to be abundantly expressed in three of seven human T-cell lymphomas tested. These findings suggest that the Dlx5 can act as an oncogene by cooperating with Akt2 to promote lymphomagenesis. [Cancer Res 2008;68(5):1296–302]
Data from A First-Generation Multiplex Biomarker Analysis of Urine for the Early Detection of Prostate Cancer
Authors: Laxman Bharathi , Morris David S. , Yu Jianjun , Siddiqui Javed , Cao Jie , Mehra Rohit , Lonigro Robert J. , Tsodikov Alex , Wei John T. , Tomlins Scott A. , Chinnaiyan Arul M.
Published: March 2024

Abstract
Although prostate-specific antigen (PSA) serum level is currently the standard of care for prostate cancer screening in the United States, it lacks ideal specificity and additional biomarkers are needed to supplement or potentially replace serum PSA testing. Emerging evidence suggests that monitoring the noncoding RNA transcript PCA3 in urine may be useful in detecting prostate cancer in patients with elevated PSA levels. Here, we show that a multiplex panel of urine transcripts outperforms PCA3 transcript alone for the detection of prostate cancer. We measured the expression of seven putative prostate cancer biomarkers, including PCA3, in sedimented urine using quantitative PCR on a cohort of 234 patients presenting for biopsy or radical prostatectomy. By univariate analysis, we found that increased GOLPH2, SPINK1, and PCA3 transcript expression and TMPRSS2:ERG fusion status were significant predictors of prostate cancer. Multivariate regression analysis showed that a multiplexed model, including these biomarkers, outperformed serum PSA or PCA3 alone in detecting prostate cancer. The area under the receiver-operating characteristic curve was 0.758 for the multiplexed model versus 0.662 for PCA3 alone (P = 0.003). The sensitivity and specificity for the multiplexed model were 65.9% and 76.0%, respectively, and the positive and negative predictive values were 79.8% and 60.8%, respectively. Taken together, these results provide the framework for the development of highly optimized, multiplex urine biomarker tests for more accurate detection of prostate cancer. [Cancer Res 2008;68(3):645–9]
Data from Inhibition of Gastric Cancer Invasion and Metastasis by PLA2G2A, a Novel β-Catenin/TCF Target Gene
Authors: Ganesan Kumaresan , Ivanova Tatiana , Wu Yonghui , Rajasegaran Vikneswari , Wu Jeanie , Lee Ming Hui , Yu Kun , Rha Sun Young , Chung Hyun Cheol , Ylstra Bauke , Meijer Gerrit , Lian Kon Oi , Grabsch Heike , Tan Patrick
Published: March 2024

Abstract
Elevated expression of the PLA2G2A phospholipase in gastric cancer (GC) is associated with improved patient survival. To elucidate function and regulation of PLA2G2A in GC, we analyzed a panel of GC cell lines. PLA2G2A was specifically expressed in lines with constitutive Wnt activity, implicating β-catenin–dependent Wnt signaling as a major upstream regulator of PLA2G2A expression. The invasive ability of PLA2G2A-expressing AGS cells was enhanced by PLA2G2A silencing, whereas cellular migration in non–PLA2G2A-expressing N87 cells was inhibited by enforced PLA2G2A expression, indicating that PLA2G2A is both necessary and sufficient to function as an inhibitor of GC invasion in vitro. We provide evidence that antiinvasive effect of PLA2G2A occurs, at least in part, through its ability to inhibit the S100A4 metastasis mediator gene. Consistent with its invasion inhibitor role, PLA2G2A expression was elevated in primary gastric, colon, and prostrate early-stage tumors, but was decreased in metastatic and late-stage tumors. There was a strong association between PLA2G2A promoter methylation status and PLA2G2A expression, suggesting that the loss of PLA2G2A expression in late-stage cancers may be due to epigenetic silencing. Supporting this, among the non–PLA2G2A-expressing lines, pharmacologic inhibition of epigenetic silencing reactivated PLA2G2A in Wnt-active lines, but in non–Wnt-active lines, a combination of Wnt hyperactivation and inhibition of epigenetic silencing were both required for PLA2G2A reactivation. Our results highlight the complexity of PLA2G2A regulation and provide functional evidence for PLA2G2A as an important regulator of invasion and metastasis in GC. [Cancer Res 2008;68(11):4277–86]
Data from The Tumor Suppressor LKB1 Regulates Lung Cancer Cell Polarity by Mediating cdc42 Recruitment and Activity
Authors: Zhang Shumin , Schafer-Hales Katherine , Khuri Fadlo R. , Zhou Wei , Vertino Paula M. , Marcus Adam I.
Published: March 2024

Abstract
The tumor suppressor LKB1 is mutated in 30% of non–small cell lung cancer (NSCLC) tumors and cell lines and is proposed to be a key regulator of epithelial cell polarity; however, how LKB1 regulates cancer cell polarity is not known. The experiments described herein show for the first time that LKB1 is a dynamic, actin-associated protein that rapidly polarizes to the leading edge of motile cancer cells. LKB1 proves to be essential for NSCLC polarity, because LKB1 depletion results in classic cell polarity defects, such as aberrant Golgi positioning, reduced lamellipodia formation, and aberrant morphology. To probe how LKB1 regulates these events, we show that LKB1 colocalizes at the cellular leading edge with two key components of the polarity pathway — the small rho GTPase cdc42 and its downstream binding partner p21-activated kinase (PAK). Importantly, LKB1 functionality is required for cdc42 polarization to the leading edge, maintaining active cdc42 levels, and downstream PAK phosphorylation. To do this, LKB1 interacts only with active form of cdc42 and PAK, but not with inactive cdc42. Taken together, these results show that LKB1 is a critical mediator of the NSCLC polarity program in lung cancer cells through a novel LKB1-cdc42-PAK pathway. [Cancer Res 2008;68(3):740–8]
Data from Prostaglandin E2 Regulates Tumor Angiogenesis in Prostate Cancer
Authors: Jain Shalini , Chakraborty Goutam , Raja Remya , Kale Smita , Kundu Gopal C.
Published: March 2024

Abstract
In cancer management, the cyclooxygenase (COX)–targeted approach has shown great promise in anticancer therapeutics. However, the use of COX-2 inhibitors has side effects and health hazards; thus, targeting its major metabolite prostaglandin E2 (PGE2)–mediated signaling pathway might be a rational approach for the next generation of cancer management. Recent studies on several in vitro and in vivo models have revealed that elevated expression of COX-2 correlates with prostate tumor growth and angiogenesis. In this study, we have shown the in-depth molecular mechanism and the PGE2 activation of the epidermal growth factor receptor and β3 integrin through E prostanoid 2 (EP2)–mediated and EP4-mediated pathways, which lead to activator protein-1 (AP-1) activation. Moreover, PGE2 also induces activating transcription factor-4 (ATF-4) activation and stimulates cross-talk between ATF-4 and AP-1, which is unidirectional toward AP-1, which leads to the increased expressions of urokinase-type plasminogen activator and vascular endothelial growth factor and, eventually, regulates prostate tumor cell motility. In vivo Matrigel angiogenesis assay data revealed that PGE2 induces angiogenesis through EP2 and EP4. Human prostate cancer specimen analysis also supported our in vitro and in vivo studies. Our data suggest that targeting PGE2 signaling pathway (i.e., blocking EP2 and EP4 receptors) might be a rational therapeutic approach for overcoming the side effects of COX-2 inhibitors and that this might be a novel strategy for the next generation of prostate cancer management. [Cancer Res 2008;68(19):7750–9]
Data from Cyclic AMP Response Element-Binding Protein Overexpression: A Feature Associated with Negative Prognosis in Never Smokers with Non–Small Cell Lung Cancer
Authors: Seo Hye-Sook , Liu Diane D. , Bekele B. Nebiyou , Kim Mi-Kyoung , Pisters Katherine , Lippman Scott M. , Wistuba Ignacio I. , Koo Ja Seok
Published: March 2024

Abstract
Lung cancer is the leading cause of cancer deaths worldwide. Recent advances in targeted therapies hold promise for the development of new treatments for certain subsets of cancer patients by targeting specific signaling molecule. Based on the identification of the transcription factor cyclic AMP response element-binding protein (CREB) as an important regulator of growth of several types of cancers and our recent findings of its importance in normal differentiation of bronchial epithelial cells, we hypothesized that CREB plays an important pathobiologic role in lung carcinogenesis. We conducted this initial study to determine whether the expression and activation status of CREB are altered in non–small cell lung cancer (NSCLC) and of any prognostic importance in NSCLC patients. We found that the expression levels of mRNA and protein of CREB and phosphorylated CREB (p-CREB) were significantly higher in most of the NSCLC cell lines and tumor specimens than in the normal human tracheobronchial epithelial cells and adjacent normal lung tissue, respectively. Analysis of CREB mRNA expression and the CREB gene copy number showed that CREB overexpression occurred mainly at the transcriptional level. Immunohistochemical analysis of tissue microarray slides containing sections of NSCLC specimens obtained from 310 patients showed that a decreased survival duration was significantly associated with overexpression of CREB or p-CREB in never smokers but not in current or former smokers with NSCLC. These are the first reported results illustrating the potential of CREB as a molecular target for the prevention and treatment of NSCLC, especially in never smokers. [Cancer Res 2008;68(15):6065–73]