bluuebunny/crossref_metadata_2025 huggingface dataset:
Gene Expression Profiling Identifies Molecular Subtypes of Inflammatory Breast Cancer
Authors: Bertucci François , Finetti Pascal , Rougemont Jacques , Charafe-Jauffret Emmanuelle , Cervera Nathalie , Tarpin Carole , Nguyen Catherine , Xerri Luc , Houlgatte Rémi , Jacquemier Jocelyne , Viens Patrice , Birnbaum Daniel
Published: September 2005

Breast cancer is a heterogeneous disease. Comprehensive gene expression profiles obtained using DNA microarrays have revealed previously indistinguishable subtypes of noninflammatory breast cancer (NIBC) related to different features of mammary epithelial biology and significantly associated with survival. Inflammatory breast cancer (IBC) is a rare, particular, and aggressive form of disease. Here we have investigated whether the five molecular subtypes described for NIBC (luminal A and B, basal, ERBB2 overexpressing, and normal breast-like) were also present in IBC. We monitored the RNA expression of ∼8,000 genes in 83 breast tissue samples including 37 IBC, 44 NIBC, and 2 normal breast samples. Hierarchical clustering identified the five subtypes of breast cancer in both NIBC and IBC samples. These subtypes were highly similar to those defined in previous studies and associated with similar histoclinical features. The robustness of this classification was confirmed by the use of both alternative gene set and analysis method, and the results were corroborated at the protein level. Furthermore, we show that the differences in gene expression between NIBC and IBC and between IBC with and without pathologic complete response that we have recently reported persist in each subtype. Our results show that the expression signatures defining molecular subtypes of NIBC are also present in IBC. Obtained using different patient series and different microarray platforms, they reinforce confidence in the expression-based molecular taxonomy but also give evidence for its universality in breast cancer, independently of a specific clinical form.
Hypoxia Stimulates Carcinoma Invasion by Stabilizing Microtubules and Promoting the Rab11 Trafficking of the α6β4 Integrin
Authors: Yoon Sang-Oh , Shin Sejeong , Mercurio Arthur M.
Published: September 2005

Hypoxia plays a key role in tumor cell survival, invasion, and metastasis. Here we show that hypoxia increases tumor cell invasion by the modulation of Rab11, an important molecule for vesicular trafficking, especially membrane protein recycling and translocation of proteins from trans-Golgi network to plasma membrane. Dominant-negative Rab11 dramatically decreased hypoxia-induced invasion of MDA-MB-231 breast carcinoma cells without affecting cell apoptosis. Hypoxia-induced Rab11 trafficking is regulated by microtubule stability, as evidenced by the findings that hypoxia increases Glu tubulin and that colchicine blocks Rab11 trafficking and invasion. Inhibition of GSK-3β activity by hypoxia seems to be central to microtubule stabilization and invasion. In fact, expression of a dominant-negative GSK-3β was sufficient to stimulate invasion in normoxia. One target of Rab11-mediated trafficking that contributes to invasion is the integrin α6β4. Hypoxia induced a significant increase in α6β4 surface expression but it had no effect on the surface expression of α3β1. This increase is dependent on Rab11 and stable microtubules. In summary, we identify vesicle trafficking as a novel target of hypoxic stimulation that is important for tumor invasion.
Cytochrome P450 2J2 Promotes the Neoplastic Phenotype of Carcinoma Cells and Is Up-regulated in Human Tumors
Authors: Jiang Jian-Gang , Chen Chun-Lian , Card Jeffrey W. , Yang Shilin , Chen Ji-Xiong , Fu Xiang-Ning , Ning Yao-Gui , Xiao Xiao , Zeldin Darryl C. , Wang Dao Wen
Published: September 2005

Cytochrome P450 (CYP) arachidonic acid epoxygenase 2J2 converts arachidonic acid to four regioisomeric epoxyeicosatrienoic acids, which exert diverse biological activities in cardiovascular system and endothelial cells. However, it is unknown whether this enzyme highly expresses and plays any role in cancer. In this study, we found that very strong and selective CYP2J2 expression was detected in human carcinoma tissues in 101 of 130 patients (77%) as well as eight human carcinoma cell lines but undetectable in adjacent normal tissues and nontumoric human cell lines by Western, reverse transcription-PCR, and immunohistochemical staining. In addition, forced overexpression of CYP2J2, and CYP BM3F87V or addition of epoxyeicosatrienoic acids (EET) in cultured carcinoma cell lines in vitro markedly accelerated proliferation by analyses of 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, cell accounts, and cell cycle analysis, and protected carcinoma cells from apoptosis induced by tumor necrosis factor α (TNF-α) in cultures. In contrast, antisense 2J2 transfection or addition of epoxygenase inhibitors 17-ODYA inhibited proliferation and accelerated cell apoptosis induced by TNF-α. Examination of signaling pathways on the effects of CYP2J2 and EETs revealed activation of mitogen-activated protein kinases and PI3 kinase-AKT systems and elevation of epithelial growth factor receptor phosphorylation level. These results strongly suggest that CYP epoxygenase 2J2 plays a previously unknown role in promotion of the neoplastic cellular phenotype and in the pathogenesis of a variety of human cancers.
Antivascular Therapy of Human Follicular Thyroid Cancer Experimental Bone Metastasis by Blockade of Epidermal Growth Factor Receptor and Vascular Growth Factor Receptor Phosphorylation
Authors: Younes Maher Nabil , Yigitbasi Orhan Gazi , Park Young Wook , Kim Sun-Jin , Jasser Samar A. , Hawthorne Valerie Stone , Yazici Yasemin Dakak , Mandal Mahitosh , Bekele Benjamin Nebiyou , Bucana Corazon D. , Fidler Isaiah J. , Myers Jeffrey N.
Published: September 2005

Patients suffering from bone metastases of follicular thyroid carcinoma (FTC) have a poor prognosis because of the lack of effective treatment strategies. The overexpression of epidermal growth factor receptor (EGFR) associated with increased vascularity has been implicated in the pathogenesis of FTC and subsequent bone metastases. We hypothesized that inhibiting the phosphorylation of the EGFR and vascular endothelial growth factor receptor (VEGFR) by AEE788, a dual tyrosine kinase inhibitor of EGFR and VEGFR, in combination with paclitaxel would inhibit experimental FTC bone lesions and preserve bone structure. We tested this hypothesis using the human WRO FTC cell line. In culture, AEE788 inhibited the EGF-mediated phosphorylation of EGFR, VEGFR2, mitogen-activated protein kinase, and Akt in culture. AEE788, alone and in combination with paclitaxel, inhibited cell growth and induced apoptosis. When WRO cells were injected into the tibia of nude mice, tumor and endothelial cells within the lesions expressed phosphorylated EGFR, VEGFR, Akt, and mitogen-activated protein kinase that were inhibited by the oral administration of AEE788. Therapy consisting of orally given AEE788 and i.p. injected paclitaxel induced a high level of apoptosis in tumor-associated endothelial cells and tumor cells with the inhibition of tumor growth in the bone and the preservation of bone structure. Collectively, these data show that blocking the phosphorylation of EGFR and VEGFR with AEE788 combined with paclitaxel can significantly inhibit experimental human FTC in the bone of nude mice.
Omega-3 Polyunsaturated Fatty Acids Regulate Syndecan-1 Expression in Human Breast Cancer Cells
Authors: Sun Haiguo , Berquin Isabelle M. , Edwards Iris J.
Published: September 2005

Human epidemiologic studies and animal model studies support a role for n-3 polyunsaturated fatty acids (n-3 PUFA) in prevention or inhibition of breast cancer. However, mechanisms for this protection remain unclear. Syndecan-1 is a heparan sulfate proteoglycan, expressed on the surface of mammary epithelial cells and known to regulate many biological processes, including cytoskeletal organization, growth factor signaling, and cell-cell adhesion. We studied effects of n-3 PUFA on syndecan-1 expression in human mammary cell lines. PUFA were delivered to cells by low-density lipoproteins (LDL) isolated from the plasma of monkeys fed diets enriched in fish oil (n-3 PUFA) or linoleic acid (n-6 PUFA). Proteoglycan synthesis was measured by incorporation of [35S]-sodium sulfate. No effect of either LDL was observed in nontumorigenic MCF-10A cells, whereas in MCF-7 breast cancer cells, treatment with n-3–enriched LDL but not n-6–enriched LDL resulted in significantly greater synthesis of a proteoglycan identified by immunoprecipitation as syndecan-1. Using real-time reverse transcription-PCR (RT-PCR), it was shown that n-3–enriched LDL significantly increased the expression of syndecan-1 mRNA in a dose-dependent manner and maximal effective time at 8 hours of treatment. The effect was mimicked by an agonist for peroxisome proliferator-activated receptor γ (PPARγ) and eliminated by the presence of PPARγ antagonist suggesting a role for PPARγ in syndecan enhancement. Our studies show that n-3 LDL modifies the production of syndecan-1 in human breast cancer cells and suggest that biological processes regulated by syndecan-1 may be modified through LDL delivery of n-3 PUFA.
Cancer Susceptibility in Nasopharyngeal Carcinoma Families—A Population-Based Cohort Study
Authors: Friborg Jeppe , Wohlfahrt Jan , Koch Anders , Storm Hans , Olsen Ove R. , Melbye Mads
Published: September 2005

Undifferentiated nasopharyngeal carcinoma is a result of environmental factors, in particular EBV infection, affecting genetically susceptible individuals. The familial risk of nasopharyngeal carcinoma is among the highest of any malignancy. Whether this susceptibility is restricted to nasopharyngeal carcinoma is unknown as information on the risk of other cancers in relatives is limited. We did a population-based study of the cancer incidence in nasopharyngeal carcinoma families in Greenland, a nasopharyngeal carcinoma–endemic area. Using population-based registers, a cohort of all persons born in Greenland was followed from 1973 to 2002. In this cohort, 134 individuals developed nasopharyngeal carcinoma and their relatives were identified through registers and interviews. Subsequently, the occurrence of cancer was determined by linkage to the population-based cancer register and the risk of cancer in nasopharyngeal carcinoma relatives and nonrelatives compared by relative risks. Among 766 first-degree relatives, the relative risk of nasopharyngeal carcinoma following the family index case was 8.0 [95% confidence interval (95% CI), 4.1-14.0]. Sex and age of the relative or the index case had no modifying effect on the familial risk of nasopharyngeal carcinoma. The relative risks of carcinoma of the salivary glands, 8.4 (95% CI, 2.7-19.5), and uterine cervix, 2.2 (95% CI, 1.1-3.9), were also significantly increased. In families with multiple cases of nasopharyngeal carcinoma, the risk of other cancers than nasopharyngeal carcinoma was further increased. These results indicate that the increased risk of cancer in nasopharyngeal carcinoma families is not restricted to nasopharyngeal carcinoma, but extends to the virally associated cancers of the salivary glands and cervical uteri.
Endogenous Retrovirus Expression Is Required for Murine Melanoma Tumor Growth In vivo
Authors: Mangeney Marianne , Pothlichet Julien , Renard Martial , Ducos Bertrand , Heidmann Thierry
Published: September 2005

Tumor development is a multistep process in which both genetic and epigenetic events cooperate for the emergence of a malignant clone. The possibility that endogenous retroviruses promote the expansion of a neoplastic clone by subverting immune surveillance has been proposed, but remained elusive. Here we show that knocking down—by RNA interference—an endogenous retrovirus spontaneously induced in the B16 murine melanoma results in the rejection of the tumor cells in immunocompetent mice, under conditions where control melanoma cells grow into lethal tumors. The knockdown does not modify the transformed phenotype of the cells, as measured both in vitro by a soft agar assay and in vivo by tumor cell proliferation in immunoincompetent (X-irradiated and severe combined immunodeficiency) mice. Tumor rejection can be reverted upon adoptive transfer of regulatory T cells from control melanoma-engrafted mice, as well as upon reexpression of the sole envelope gene of the endogenous retrovirus in the knocked down cells. These results show that endogenous retroviruses can be essential for a regulatory T-cell–mediated subversion of immune surveillance and could be relevant to human tumors where such elements—and especially their envelope gene—are induced.
The t(8;9)(p22;p24) Is a Recurrent Abnormality in Chronic and Acute Leukemia that Fuses PCM1 to JAK2
Authors: Reiter Andreas , Walz Christoph , Watmore Ann , Schoch Claudia , Blau Ilona , Schlegelberger Brigitte , Berger Ute , Telford Nick , Aruliah Shilani , Yin John A. , Vanstraelen Danny , Barker Helen F. , Taylor Peter C. , O'Driscoll Aisling , Benedetti Fabio , Rudolph Cornelia , Kolb Hans-Jochem , Hochhaus Andreas , Hehlmann Rüdiger , Chase Andrew , Cross Nicholas C.P.
Published: September 2005

We have identified a t(8;9)(p21-23;p23-24) in seven male patients (mean age 50, range 32-74) with diverse hematologic malignancies and clinical outcomes: atypical chronic myeloid leukemia/chronic eosinophilic leukemia (n = 5), secondary acute myeloid leukemia (n = 1), and pre-B-cell acute lymphoblastic leukemia (n = 1). Initial fluorescence in situ hybridization studies of one patient indicated that the nonreceptor tyrosine kinase Janus-activated kinase 2 (JAK2) at 9p24 was disrupted. Rapid amplification of cDNA ends-PCR identified the 8p22 partner gene as human autoantigen pericentriolar material (PCM1), a gene encoding a large centrosomal protein with multiple coiled-coil domains. Reverse transcription-PCR and fluorescence in situ hybridization confirmed the fusion in this case and also identified PCM1–JAK2 in the six other t(8;9) patients. The breakpoints were variable in both genes, but in all cases the chimeric mRNA is predicted to encode a protein that retains several of the predicted coiled-coil domains from PCM1 and the entire tyrosine kinase domain of JAK2. Reciprocal JAK2–PCM1 mRNA was not detected in any patient. We conclude that human autoantigen pericentriolar material (PCM1)–JAK2 is a novel, recurrent fusion gene in hematologic malignancies. Patients with PCM1–JAK2 disease are attractive candidates for targeted signal transduction therapy.
Identification of a Genetic Signature of Activated Signal Transducer and Activator of Transcription 3 in Human Tumors
Authors: Alvarez James V. , Febbo Phillip G. , Ramaswamy Sridhar , Loda Massimo , Richardson Andrea , Frank David A.
Published: September 2005

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that is activated in diverse human tumors and may play a direct role in malignant transformation. However, the full complement of target genes that STAT3 regulates to promote oncogenesis is not known. We created a system to express a constitutively active form of STAT3, STAT3-C, in mouse fibroblasts and used it to identify STAT3 targets. We showed that a subset of these targets, which include transcription factors regulating cell growth, survival, and differentiation, are coexpressed in a range of human tumors. Using immunohistochemical staining of tissue microarrays, we showed that these targets are enriched in breast and prostate tumors harboring activated STAT3. Finally, we showed that STAT3 is required for the expression of these genes in a breast cancer cell line. Taken together, these results identify a cohort of STAT3 targets that may mediate its role in oncogenesis.
Proximity of TPR and NTRK1 Rearranging Loci in Human Thyrocytes
Authors: Roccato Emanuela , Bressan Paola , Sabatella Guido , Rumio Cristiano , Vizzotto Laura , Pierotti Marco A. , Greco Angela
Published: September 2005

Chromosomal rearrangements are frequently associated with cancer; the mechanisms underlying their cell-type specificity are poorly understood. Papillary thyroid carcinomas are marked by a high frequency of chromosome rearrangements involving the RET and NTRK1 tyrosine kinase receptor genes and producing RET and TRK oncogenes. An explanation for the propensity of thyrocytes to undergo gene rearrangements has been recently proposed by Nikiforova and colleagues, who showed that the recombination between RET and H4 is favored by the loci proximity in interphase nuclei. We investigated whether the spatial proximity is a contributing factor also in the generation of the thyroid-specific TRK oncogenes. The distance between NTRK1 and its oncogenic partner TPR was determined by two-color fluorescence in situ hybridization and two-dimensional microscopy. A three-dimensional reconstruction of the data was also done. We show that the two loci in thyrocytes nuclei display a distance reduced with respect to peripheral blood lymphocytes, thus supporting the notion that spatial proximity of translocation-prone gene loci may favor gene rearrangements.
Proteolytic Processing Converts the Repelling Signal Sema3E into an Inducer of Invasive Growth and Lung Metastasis
Authors: Christensen Claus , Ambartsumian Noona , Gilestro Giorgio , Thomsen Birthe , Comoglio Paolo , Tamagnone Luca , Guldberg Per , Lukanidin Eugene
Published: September 2005

We have previously shown that the expression of a semaphorin, known as a repelling cue in axon guidance, Sema3E, correlates with the ability to form lung metastasis in murine adenocarcinoma cell models. Now, besides providing evidence for the relevance of SEMA3E to human disease by showing that SEMA3E is frequently expressed in human cancer cell lines and solid tumors from breast cancer patients, we show biological activities of Sema3E, which support the implication of Sema3E in tumor progression and metastasis. In vivo, expression of Sema3E in mammary adenocarcinoma cells induces the ability to form experimental lung metastasis, and in vitro, the Sema3E protein exhibits both migration and growth promoting activity on endothelial cells and pheochromocytoma cells. This represents the first evidence of a metastasis-promoting function of a class 3 semaphorin, as this class of genes has hitherto been implicated in tumor biology only as tumor suppressors and negative regulators of growth. Moreover, we show that the full-size Sema3E protein is converted into a p61-Sema3E isoform due to furin-dependent processing, and by analyzing processing-deficient and truncated forms, we show that the generation of p61-Sema3E is required and sufficient for the function of Sema3E in lung metastasis, cell migration, invasive growth, and extracellular signal–regulated kinase 1/2 activation of endothelial cells. These findings suggest that certain breast cancer cells may increase their lung-colonizing ability by converting the growth repellent, Sema3E, into a growth attractant and point to a type of semaphorin signaling different from the conventional signaling induced by full-size dimeric class 3 semaphorins.
Global Gene Expression Profiling of Circulating Tumor Cells
Authors: Smirnov Denis A. , Zweitzig Daniel R. , Foulk Bradley W. , Miller M. Craig , Doyle Gerald V. , Pienta Kenneth J. , Meropol Neal J. , Weiner Louis M. , Cohen Steven J. , Moreno Jose G. , Connelly Mark C. , Terstappen Leon W.M.M. , O'Hara S. Mark
Published: September 2005

Metastases from primary tumors are responsible for most cancer deaths. It has been shown that circulating tumor cells (CTCs) can be detected in the peripheral blood of patients with a variety of metastatic cancers and that the presence of these cells is associated with poor clinical outcomes. Characterization of CTCs in metastatic cancer patients could provide additional information to augment management of the disease. Here, we describe a novel approach for the identification of molecular markers to detect and characterize CTCs in peripheral blood. Using an integrated platform to immunomagnetically isolate and immunofluorescently detect CTCs, we obtained blood containing ≥100 CTCs from one metastatic colorectal, one metastatic prostate, and one metastatic breast cancer patient. Using the RNA extracted from the CTC-enriched portion of the sample and comparing it with the RNA extracted from the corresponding CTC-depleted portion, for the first time, global gene expression profiles from CTCs were generated and a list of cancer-specific, CTC-specific genes was obtained. Subsequently, samples immunomagnetically enriched for CTCs from 74 metastatic cancer patients and 50 normal donors were used to confirm by quantitative real-time reverse transcription-PCR CTC-specific expression of selected genes and to show that gene expression profiles for CTCs may be used to distinguish normal donors from advanced cancer patients as well as to differentiate among the three different metastatic cancers. Genes such as AGR2, S100A14, S100A16, FABP1, and others were found useful for detection of CTCs in peripheral blood of advanced cancer patients.
Glioblastomas Induce T-Lymphocyte Death by Two Distinct Pathways Involving Gangliosides and CD70
Authors: Chahlavi Ali , Rayman Patricia , Richmond Amy L. , Biswas Kaushik , Zhang Renliang , Vogelbaum Michael , Tannenbaum Charles , Barnett Gene , Finke James H.
Published: September 2005

Here we report that glioblastoma multiforme (GBM) mediates immunosuppression by promoting T-cell death via tumor-associated CD70 and gangliosides that act through receptor-dependent and receptor-independent pathways, respectively. GBM lines cocultured with T cells induced lymphocyte death. The GBM lines were characterized for their expression of CD70, Fas ligand (FasL), and tumor necrosis factor-α (TNF-α), and the possible participation of those molecules in T-cell killing was assessed by doing GBM/T cell cocultures in the presence of anti-CD70 antibodies, Fas fusion proteins, or anti-TNF-α antibodies. CD70 but not TNF-α or FasL is responsible for initiating T-cell death via the receptor-dependent pathway. Of the four GBM cell lines that induced T-cell death, three highly expressed CD70. Two nonapoptogenic GBM lines (CCF3 and U138), on the other hand, had only minimally detectable CD70 expression. Blocking experiments with the anti-CD70 antibody confirmed that elevated CD70 levels were involved in the apoptogenicity of the three GBM lines expressing that molecule. Gangliosides were found to participate in the induction of T-cell apoptosis, because the glucosylceramide synthase inhibitor (PPPP) significantly reduced the abilities of all four apoptogenic lines to kill the lymphocytes. High-performance liquid chromatography (HPLC) and mass spectroscopy revealed that GM2, GM2-like gangliosides, and GD1a were synthesized in abundance by all four apoptogenic GBM lines but not by the two GBMs lacking activity. Furthermore, gangliosides isolated from GBM lines as well as HPLC fractions containing GM2 and GD1a were directly apoptogenic for T cells. Our results indicate that CD70 and gangliosides are both products synthesized by GBMs that may be key mediators of T-cell apoptosis and likely contribute to the T-cell dysfunction observed within the tumor microenvironment.
Suppression of Prostate Tumor Cell Growth by Stromal Cell Prostaglandin D Synthase–Derived Products
Authors: Kim Jeri , Yang Peiying , Suraokar Milind , Sabichi Anita L. , Llansa Norma D. , Mendoza Gabriela , Subbarayan Vemparalla , Logothetis Christopher J. , Newman Robert A. , Lippman Scott M. , Menter David G.
Published: September 2005

Stromal-epithelial interactions and the bioactive molecules produced by these interactions maintain tissue homeostasis and influence carcinogenesis. Bioactive prostaglandins produced by prostaglandin synthases and secreted by the prostate into seminal plasma are thought to support reproduction, but their endogenous effects on cancer formation remain unresolved. No studies to date have examined prostaglandin enzyme production or prostaglandin metabolism in normal prostate stromal cells. Our results show that lipocalin-type prostaglandin D synthase (L-PGDS) and prostaglandin D2 (PGD2) metabolites produced by normal prostate stromal cells inhibited tumor cell growth through a peroxisome proliferator–activated receptor γ (PPARγ)–dependent mechanism. Enzymatic products of stromal cell L-PGDS included high levels of PGD2 and 15-deoxy-Δ12,14-PGD2 but low levels of 15-deoxy-Δ12,14-prostaglandin J2. These PGD2 metabolites activated the PPARγ ligand-binding domain and the peroxisome proliferator response element reporter systems. Thus, growth suppression of PPARγ-expressing tumor cells by PGD2 metabolites in the prostate microenvironment is likely to be an endogenous mechanism involved in tumor suppression that potentially contributes to the indolence and long latency period of this disease.
The Heat Shock Protein 90 Inhibitor, 17-Allylamino-17-demethoxygeldanamycin, Enhances Osteoclast Formation and Potentiates Bone Metastasis of a Human Breast Cancer Cell Line
Authors: Price John T. , Quinn Julian M.W. , Sims Natalie A. , Vieusseux Jessica , Waldeck Kelly , Docherty Susan E. , Myers Damian , Nakamura Akira , Waltham Mark C. , Gillespie Matthew T. , Thompson Erik W.
Published: September 2005

Breast cancer metastasis to the bone occurs frequently, causing numerous complications including severe pain, fracture, hypercalcemia, and paralysis. Despite its prevalence and severity, few effective therapies exist. To address this, we examined whether the heat shock protein 90 (Hsp90) inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), would be efficacious in inhibiting breast cancer metastasis to bone. Utilizing the human breast cancer subline, MDA-MB-231SA, previously in vivo selected for its enhanced ability to generate osteolytic bone lesions, we determined that 17-AAG potently inhibited its in vitro proliferation and migration. Moreover, 17-AAG significantly reduced MDA-MB-231SA tumor growth in the mammary-fat pad of nude mice. Despite these findings, 17-AAG enhanced the incidence of bone metastasis and osteolytic lesions following intracardiac inoculation in the nude mouse. Consistent with these findings, 17-AAG enhanced osteoclast formation 2- to 4-fold in mouse bone marrow/osteoblast cocultures, receptor activator of nuclear factor κB ligand (RANKL)–stimulated bone marrow, and RAW264.7 cell models of in vitro osteoclastogenesis. Moreover, the drug enhanced osteoclastogenesis in human cord blood progenitor cells, demonstrating that its effects were not limited to mouse models. In addition to 17-AAG, other Hsp90 inhibitors, such as radicicol and herbimycin A, also enhanced osteoclastogenesis. A pro-osteolytic action of 17-AAG independent of tumor presence was also determined in vivo, in which 17-AAG–treated tumor-naïve mice had reduced trabecular bone volume with an associated increase in osteoclast number. Thus, HSP90 inhibitors can stimulate osteoclast formation, which may underlie the increased incidence of osteolysis and skeletal tumor incidence caused by 17-AAG in vivo. These data suggest an important contraindication to the Hsp90 targeted cancer therapy currently undergoing clinical trial.
LMO3 Interacts with Neuronal Transcription Factor, HEN2, and Acts as an Oncogene in Neuroblastoma
Authors: Aoyama Mineyoshi , Ozaki Toshinori , Inuzuka Hiroyuki , Tomotsune Daihachiro , Hirato Junko , Okamoto Yoshiaki , Tokita Hisashi , Ohira Miki , Nakagawara Akira
Published: September 2005

LIM-only proteins (LMO), which consist of LMO1, LMO2, LMO3, and LMO4, are involved in cell fate determination and differentiation during embryonic development. Accumulating evidence suggests that LMO1 and LMO2 act as oncogenic proteins in T-cell acute lymphoblastic leukemia, whereas LMO4 has recently been implicated in the genesis of breast cancer. However, little is known about the role of LMO3 in either tumorigenesis or development. In the present study, we have identified LMO3 and HEN2, which encodes a neuronal basic helix-loop-helix protein, as genes whose expression levels were higher in unfavorable neuroblastomas compared with those of favorable tumors. Immunoprecipitation and immunostaining experiments showed that LMO3 was associated with HEN2 in mammalian cell nucleus. Human neuroblastoma SH-SY5Y cells stably overexpressing LMO3 showed a marked increase in cell growth, a promotion of colony formation in soft agar medium, and a rapid tumor growth in nude mice compared with the control transfectants. More importantly, the increased expression of LMO3 and HEN2 was significantly associated with a poor prognosis in 87 primary neuroblastomas. These results suggest that the deregulated expression of neuronal-specific LMO3 and HEN2 contributes to the genesis and progression of human neuroblastoma in a lineage-specific manner.
Identification of Leukocyte E-Selectin Ligands, P-Selectin Glycoprotein Ligand-1 and E-Selectin Ligand-1, on Human Metastatic Prostate Tumor Cells
Authors: Dimitroff Charles J. , Descheny Leyla , Trujillo Natalia , Kim Robert , Nguyen Vuong , Huang Wei , Pienta Kenneth J. , Kutok Jeffery L. , Rubin Mark A.
Published: September 2005

Prostate tumor cells, which characteristically metastasize to bone, initiate binding interactions with bone marrow endothelium under blood flow conditions through binding interactions with E-selectin. We hypothesized that E-selectin ligands on prostate tumor cells are directly associated with bone-metastatic potential. In this report, we elucidate the identity of E-selectin ligands on human metastatic prostate tumor cells and examine their association with prostate tumor progression and metastasis in vivo. To our surprise, we found that the E-selectin-binding form of P-selectin glycoprotein ligand-1 (PSGL-1) is expressed on the human bone-metastatic prostate tumor MDA PCa 2b cell line. Interestingly, we also found that human prostate tumor cells derived from bone, lymph node, and brain metastases expressed another leukocyte E-selectin ligand, E-selectin ligand-1 (ESL-1). Immunohistochemical analysis of PSGL-1 and ESL-1 in normal prostate tissue and in localized and metastatic prostate tumors revealed that ESL-1 was principally localized to intracellular cell membrane and expressed on all normal and malignant prostate tissue, whereas PSGL-1 was notably detected on the surfaces of bone-metastatic prostate tumor cells. These findings implicate a functional role of PSGL-1 in the bone tropism of prostate tumor cells and establish a new perspective into the molecular mechanism of human prostate tumor metastasis.
A New Perspective on Tumor Endothelial Cells: Unexpected Chromosome and Centrosome Abnormalities
Authors: Hida Kyoko , Klagsbrun Michael
Published: September 2005

It has been shown that endothelial cells in solid tumors are cytogenetically abnormal. These cells are aneuploid with multiple chromosomes and multiple centrosomes. Unlike normal endothelial cells which remain diploid in long-term culture, the aneuploidy of tumor endothelial cells is exacerbated in culture suggesting that these cells are inherently unstable. It is speculated that this instability might compromise the effectiveness of antiangiogenesis therapy.
Phenotypic Profiling of Engineered Mouse Melanomas with Manipulated Histamine Production Identifies Histamine H2 Receptor and Rho-C as Histamine-Regulated Melanoma Progression Markers
Authors: Pós Zoltán , Sáfrány Géza , Müller Kerstin , Tóth Sára , Falus András , Hegyesi Hargita
Published: September 2005

In the present study, the impact of acquired neoplastic l-histidine decarboxylase (HDC) expression, and its direct consequence, the release of histamine in the tumor environment, was assessed on melanoma tumor progression. B16-F10 mouse melanoma cells were manipulated via stable transfection, and nine novel transgenic variants were generated in triplicates, constitutively expressing the full-length sense mouse HDC mRNA, a mock control, and an antisense HDC RNA segment, respectively. Establishing both primary skin tumors and lung metastases in C57BL/6 mice, the nine variants with different histamine-releasing capacities were subjected to a comprehensive comparative progression profiling in vivo. Our analyses showed trends of markedly accelerated tumor growth (P < 0.001), and moderately increased metastatic colony-forming potential (P = 0.010) along with rising levels of local histamine production. Using RNase protection assay for screening of the melanoma progression profile, and Western blotting for subsequent result validation, we looked for molecular progression markers affected by melanoma histamine secretion. Investigation of 21 functionally clustered markers associated with tumor proliferation, angiogenesis, invasivity, metastasis formation, local or systemic immunomodulation, and histamine signaling revealed positive correlations between histamine production, tumor histamine H2 receptor and rho-C expression (P < 0.001, P = 0.002, respectively). These observations confirm the involvement of histamine in the molecular machinery of melanoma progression.
High Mobility Group A2 Potentiates Genotoxic Stress in Part through the Modulation of Basal and DNA Damage–Dependent Phosphatidylinositol 3-Kinase–Related Protein Kinase Activation
Authors: Boo Lee Ming , Lin H. Helen , Chung Vincent , Zhou Bingsen , Louie Stan G. , O'Reilly Michael A. , Yen Yun , Ann David K.
Published: September 2005

The high mobility group A2 (HMGA2) protein belongs to the architectural transcription factor HMGA family, playing a role in chromosomal organization and transcriptional regulation. We and others have previously reported that ectopic HMGA2 expression is associated with neoplastic transformation and anchorage-independent cell proliferation. Here, we reported a correlation between increased HMGA2 expression and enhanced chemosensitivity towards topoisomerase II inhibitor, doxorubicin, in breast cancer cells. Using cells exhibiting differential HMGA2 expression and small interfering RNA technique, we showed that HMGA2 expression modulates cellular response to the genotoxicity of DNA double-strand breaks. Notably, HMGA2 enhances doxorubicin-elicited cell cycle delay in sub-G1 and G2-M and augments cell cycle dysregulation on cotreatment of doxorubicin and caffeine. We further reported that HMGA2 induces a persistent Ser139 phosphorylation of histone 2A variant X, analogous to the activation by doxorubicin-mediated genotoxic stress. Moreover, this HMGA2-dependent enhancement of cytotoxicity is further extended to other double-strand breaks elicited by cisplatin and X-ray irradiation and is not restricted to one cell type. Together, we postulated that the enhanced cytotoxicity by double-strand breaks in HMGA2-expressing cells is mediated, at least in part, through the signaling pathway of which the physiologic function is to maintain genome integrity. These findings should contribute to a greater understanding of the role of HMGA2 in promoting tumorigenesis and conveying (chemo)sensitivity towards doxorubicin and other related double-strand breaks.
Characterization of Common CYP1B1 Variants with Different Capacity for Benzo[a]pyrene-7,8-Dihydrodiol Epoxide Formation from Benzo[a]pyrene
Authors: Aklillu Eleni , Øvrebø Steinar , Botnen Ingrid V. , Otter Charlotta , Ingelman-Sundberg Magnus
Published: September 2005

Cytochrome P450 1B1 (CYP1B1), an extrahepatic enzyme inducible by smoking, is overexpressed in many tumors and catalyzes the metabolic activation of procarcinogens such as polycyclic aromatic hydrocarbons. In human, CYP1B1 is genetically polymorphic and five common missense mutations causing amino acid substitution have been identified. In this study, we have investigated CYP1B1 haplotypes present in a Spanish population and carried out functional analyses of the corresponding enzymes in yeast using benzo[a]pyrene as a substrate. CYP1B1*1, CYP1B1*2, CYP1B1*3, CYP1B1*4, CYP1B1*6, and CYP1B1*7, encoding combinations of the Arg48Gly, Ala119Ser, Leu432Val, Asn453Ser, and Ala443Gly amino acid substitutions, were present at frequencies of 14.3%, 25.5%, 38.8%, 18.1%, 0.4%, and 2.6%, respectively. The variant CYP1B1 forms were heterologously expressed with human reductase in Saccharomyces cerevisiae and kinetic analyses of benzo[a]pyrene metabolism were carried out. CYP1B1.7, having the amino acid substitutions Arg48Gly, Ala119Ser, Leu432Val, and Ala443Gly, exhibited a significantly decreased capacity (P < 0.001) for the formation of (±)-benzo[a]pyrene-trans-7,8-dihydrodiol from benzo[a]pyrene as indicated by lower intrinsic clearance (Vmax/Km). A somewhat decreased clearance was observed for CYP1B1.4, whereas no significant differences in kinetic properties among the remaining variant enzymes were observed as compared with CYP1B1.1. Thus, genetic polymorphism in the CYP1B1 gene, as defined by the haplotypes investigated, might cause interindividual differences in susceptibility (e.g., to lung cancer induced by smoking). The results indicate the necessity to make molecular epidemiologic investigations regarding the association of the specific CYP1B1 haplotypes and cancer risk.
Hypoxia-Inducible Protein 2 (HIG2), a Novel Diagnostic Marker for Renal Cell Carcinoma and Potential Target for Molecular Therapy
Authors: Togashi Akira , Katagiri Toyomasa , Ashida Shingo , Fujioka Tomoaki , Maruyama Osamu , Wakumoto Yoshiaki , Sakamoto Yoshiro , Fujime Makoto , Kawachi Yoshio , Shuin Taro , Nakamura Yusuke
Published: September 2005

To identify molecules to serve as diagnostic markers for renal cell carcinoma (RCC) and as targets for novel therapeutic drugs, we investigated genome-wide expression profiles of RCCs using a cDNA microarray. We subsequently confirmed that hypoxia-inducible protein-2 (HIG2) was expressed exclusively in RCCs and fetal kidney. Induction of HIG2 cDNA into COS7 cells led to secretion of the gene product into culture medium and resulted in enhancement of cell growth. Small interfering RNA effectively inhibited expression of HIG2 in human RCC cells that endogenously expressed high levels of the protein and significantly suppressed cell growth. Moreover, addition of polyclonal anti-HIG2 antibody into culture medium induced apoptosis in RCC-derived cell lines. By binding to an extracellular domain of frizzled homologue 10 (FZD10), HIG2 protein enhanced oncogenic Wnt signaling and its own transcription, suggesting that this product is likely to function as an autocrine growth factor. ELISA analysis of clinical samples identified secretion of HIG2 protein into the plasma of RCC patients even at an early stage of tumor development, whereas it was detected at significantly lower levels in healthy volunteers or patients with chronic glomerulonephritis. The combined evidence suggests that this molecule represents a promising candidate for development of molecular-targeting therapy and could serve as a prominent diagnostic tumor marker for patients with renal carcinomas.
Phosphatase and Tensin Homologue Deleted on Chromosome 10 (PTEN) Has Nuclear Localization Signal–Like Sequences for Nuclear Import Mediated by Major Vault Protein
Authors: Chung Ji-Hyun , Ginn-Pease Margaret E. , Eng Charis
Published: September 2005

Although phosphatase and tensin homologue deleted on chromosome 10 (PTEN) localization in the nucleus and cytoplasm is established, the mechanism is unknown. PTEN is a tumor suppressor phosphatase that causes cell cycle arrest and/or apoptosis. Nuclear-cytoplasmic compartmentalization may be a novel mechanism in regulating these events. PTEN does not contain a traditional nuclear localization sequence (NLS); however, we identified putative NLS-like sequences, which we analyzed by site-directed mutagenesis and localization studies in MCF-7 cells. Two double site mutations exhibited nuclear localization defects. Furthermore, unlike wild-type PTEN, double NLS mutant PTEN did not interact with major vault protein (MVP), a previously hypothesized nuclear-cytoplasmic transport protein. We conclude that these two NLS-like sequences are required for PTEN nuclear import that is mediated by MVP. Further, we show that this MVP-mediated nuclear import is independent of PTEN phosphorylation and of the lipid and protein phosphatase activities of PTEN.
A Novel Function for Galectin-7: Promoting Tumorigenesis by Up-regulatingMMP-9Gene Expression
Authors: Demers Mélanie , Magnaldo Thierry , St-Pierre Yves
Published: September 2005

Metastasis is a multistep process by which cancer cells, after acquiring several capabilities, spread to distinct sites in the body. It is the major cause of death in individuals suffering from cancer. We have recently identified galectin-7 as a new gene associated with the progression of T cell lymphoma toward a metastatic phenotype, suggesting a possible causal relationship. The present study was designed to investigate the role of galectin-7 in lymphoma. We found that the development of thymic lymphoma was accelerated when induced by lymphoma cells overexpressing galectin-7. Moreover, transfection of an expression vector containing the galectin-7 gene in low metastatic lymphoma cells increased their metastatic behavior and confers these cells with the new ability to overcome the resistance of intercellular adhesion molecule-1–deficient mice to lymphoma dissemination. Finally, we provide data suggesting that galectin-7 modulates the aggressive behavior of lymphoma cells by controlling the expression of metastatic genes, such as MMP-9. This hypothesis is based on the following evidence: (a) galectin-7 transfectants have higher levels of MMP-9 expression, (b) addition of β-lactose completely inhibits expression of MMP-9 by galectin-7 transfectants, and (c) recombinant forms of galectin-7 induces the expression of MMP-9 in both mouse and human lymphoma cells. Our results have uncovered the existence of a previously undescribed activity, the promotion of cancer cell malignancy, to galectin-7.
Bcl-2 Acts in a Proangiogenic Signaling Pathway through Nuclear Factor-κB and CXC Chemokines
Authors: Karl Elisabeta , Warner Kristy , Zeitlin Benjamin , Kaneko Tomoatsu , Wurtzel Lindsey , Jin Taocong , Chang Jia , Wang Shaomeng , Wang Cun-Yu , Strieter Robert M. , Nunez Gabriel , Polverini Peter J. , Nör Jacques E.
Published: September 2005

Vascular endothelial growth factor (VEGF) induces expression of Bcl-2 in tumor-associated microvascular endothelial cells. We have previously reported that up-regulated Bcl-2 expression in microvascular endothelial cells is sufficient to enhance intratumoral angiogenesis and to accelerate tumor growth. We initially attributed these results to Bcl-2–mediated endothelial cell survival. However, in recent experiments, we observed that conditioned medium from Bcl-2–transduced human dermal microvascular endothelial cells (HDMEC-Bcl-2) is sufficient to induce potent neovascularization in the rat corneal assay, whereas conditioned medium from empty vector controls (HDMEC-LXSN) does not induce angiogenesis. These results cannot be attributed to the role of Bcl-2 in cell survival. To understand this unexpected observation, we did gene expression arrays that revealed that the expression of the proangiogenic chemokines interleukin-8 (CXCL8) and growth-related oncogene-α (CXCL1) is significantly higher in HDMEC exposed to VEGF and in HDMEC-Bcl-2 than in controls. Inhibition of Bcl-2 expression with small interfering RNA-Bcl-2, or the inhibition of Bcl-2 function with small molecule inhibitor BL-193, down-regulated CXCL8 and CXCL1 expression and caused marked decrease in the angiogenic potential of endothelial cells without affecting cell viability. Nuclear factor-κB (NF-κB) is highly activated in HDMEC exposed to VEGF and HDMEC-Bcl-2 cells, and genetic and chemical approaches to block the activity of NF-κB down-regulated CXCL8 and CXCL1 expression levels. These results reveal a novel function for Bcl-2 as a proangiogenic signaling molecule and suggest a role for this pathway in tumor angiogenesis.
LY294002 and LY303511 Sensitize Tumor Cells to Drug-Induced Apoptosis via Intracellular Hydrogen Peroxide Production Independent of the Phosphoinositide 3-Kinase-Akt Pathway
Authors: Poh Tze Wei , Pervaiz Shazib
Published: September 2005

The phosphoinositide 3-kinase (PI3K)-Akt pathway is constitutively active in many tumors, and inhibitors of this prosurvival network, such as LY294002, have been shown to sensitize tumor cells to death stimuli. Here, we report a novel, PI3K-independent mechanism of LY-mediated sensitization of LNCaP prostate carcinoma cells to drug-induced apoptosis. Preincubation of tumor cells to LY294002 or its inactive analogue LY303511 resulted in a significant increase in intracellular hydrogen peroxide (H2O2) production and enhanced sensitivity to nonapoptotic concentrations of the chemotherapeutic agent vincristine. The critical role of intracellular H2O2 in LY-induced death sensitization is corroborated by transient transfection of cells with a vector containing human catalase gene. Indeed, overexpression of catalase significantly blocked the amplifying effect of LY pretreatment on caspase-2 and caspase-3 activation and cell death triggered by vincristine. Furthermore, the inability of wortmannin, another inhibitor of PI3K, to induce an increase in H2O2 production at doses that effectively blocked Akt phosphorylation provides strong evidence to unlink inhibition of PI3K from intracellular H2O2 production. These data strongly support death-sensitizing effect of LY compounds independent of the PI3K pathway and underscore the critical role of H2O2 in creating a permissive intracellular milieu for efficient drug-induced execution of tumor cells.
Increased Proteasome Activity, Ubiquitin-Conjugating Enzymes, and eEF1A Translation Factor Detected in Breast Cancer Tissue
Authors: Chen Li , Madura Kiran
Published: September 2005

The ubiquitin (Ub)/proteasome pathway facilitates the degradation of damaged proteins and regulators of growth and stress response. The activation of this pathway in various cancers and malignancies has been described, and several genetic determinants of breast cancer, including BRCA1 and BRCA2, are linked to protein degradation. To investigate the involvement of the Ub/proteasome system in breast cancer, we examined a collection of 25 patient-matched breast cancer and normal adjacent tissues and detected activation of numerous components of the Ub/proteasome pathway. The activity of the proteasome, and levels of proteasome subunits and various targeting factors, were increased in >90% of primary breast cancer tissue specimens. In contrast, no activation was observed in benign solid tumors, indicating that the response is specific to abnormal growth in neoplastic cells. Additionally, the accumulation of high levels of certain Ub-conjugating enzymes (UbcH1, UbcH2, and UbcH5), was specific to breast cancer, as no change in abundance was detected in primary colon cancer tissue extracts. Surprisingly, the Ub/proteasome system was not activated in a well-characterized cell culture–based breast cancer model system. Collectively, these findings suggest that the analysis of primary breast cancer tissue samples will be indispensable for the biochemical characterization of neoplastic growth and for the development of therapeutics.