bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Industasis, a Promotion of Tumor Formation by Nontumorigenic Stray Cells
Authors: Pajer Petr , Karafiát Vít , Pec̆enka Vladimír , Pru̇ková Dana , Dudlová Jana , Plachý Jiří , Kašparová Petra , Dvořák Michal
Published: March 2024

Abstract
A tumor cell is formed when a critical amount of endogenous and/or exogenous tumorigenic stimuli is exceeded. We have shown that the transient presence of nontumorigenic stray cells in tissues of experimental animals that contain cells with a subcritical set of genetic mutations can act as a tumor-promoting stimulus. To induce somatic mutations in all chicken tissues, we have used the MAV-2 retroviral insertion system that almost exclusively generates nephroblastomas. MAV-2 mutagenized animals i.v. inoculated with nonmalignant cells developed early clonal lung tumors before nephroblastomas. Importantly, the injected cells did not become a component of resultant tumors. Lung tumors displayed specific mutational signature characterized by an insertion of MAV-2 provirus into the fyn-related kinase (frk) promoter that results in the overexpression of the frk gene. In contrast, plag1, foxP, and twist genes were most often mutagenized in nephroblastomas. Based on such observations, we propose the mechanism termed industasis, a promotion of fully malignant phenotype of incipient tumor cell by stray cells, and hypothesize that it might be the underlying cause of human multiple primary tumors. [Cancer Res 2009;69(11):4605–12]
Data from Moderate Increase in Mdr1a/1b Expression Causes In vivo Resistance to Doxorubicin in a Mouse Model for Hereditary Breast Cancer
Authors: Pajic Marina , Iyer Jayasree K. , Kersbergen Ariena , van der Burg Eline , Nygren Anders O.H. , Jonkers Jos , Borst Piet , Rottenberg Sven
Published: March 2024

Abstract
We have found previously that acquired doxorubicin resistance in a genetically engineered mouse model for BRCA1-related breast cancer was associated with increased expression of the mouse multidrug resistance (Mdr1) genes, which encode the drug efflux transporter ATP-binding cassette B1/P-glycoprotein (P-gp). Here, we show that even moderate increases of Mdr1 expression (as low as 5-fold) are sufficient to cause doxorubicin resistance. These moderately elevated tumor P-gp levels are below those found in some normal tissues, such as the gut. The resistant phenotype could be completely reversed by the third-generation P-gp inhibitor tariquidar, which provides a useful strategy to circumvent this type of acquired doxorubicin resistance. The presence of MDR1A in drug-resistant tumors with a moderate increase in Mdr1a transcripts could be shown with a newly generated chicken antibody against a mouse P-gp peptide. Our data show the usefulness of realistic preclinical models to characterize levels of Mdr1 gene expression that are sufficient to cause resistance. [Cancer Res 2009;69(16):6396–9]
Data from Secreted Frizzle-Related Protein 2 Stimulates Angiogenesis via a Calcineurin/NFAT Signaling Pathway
Authors: Courtwright Andrew , Siamakpour-Reihani Sharareh , Arbiser Jack L. , Banet Natalie , Hilliard Eleanor , Fried Levi , Livasy Chad , Ketelsen David , Nepal Desh Bandhu , Perou Charles M. , Patterson Cam , Klauber-DeMore Nancy
Published: March 2024

Abstract
Secreted frizzle-related protein 2 (SFRP2), a modulator of Wnt signaling, has recently been found to be overexpressed in the vasculature of 85% of human breast tumors; however, its role in angiogenesis is unknown. We found that SFRP2 induced angiogenesis in the mouse Matrigel plug assay and the chick chorioallantoic membrane assay. SFRP2 inhibited hypoxia induced endothelial cell apoptosis, increased endothelial cell migration, and induced endothelial tube formation. The canonical Wnt pathway was not affected by SFRP2 in endothelial cells; however, a component of the noncanonical Wnt/Ca2+ pathway was affected by SFRP2 as shown by an increase in NFATc3 in the nuclear fraction of SFRP2-treated endothelial cells. Tacrolimus, a calcineurin inhibitor that inhibits dephosphorylation of NFAT, inhibited SFRP2-induced endothelial tube formation. Tacrolimus 3 mg/kg/d inhibited the growth of SVR angiosarcoma xenografts in mice by 46% (P = 0.04). In conclusion, SFRP2 is a novel stimulator of angiogenesis that stimulates angiogenesis via a calcineurin/NFAT pathway and may be a favorable target for the inhibition of angiogenesis in solid tumors. [Cancer Res 2009;69(11):4621–8]
Data from Confounding Effects in “A Six-Gene Signature Predicting Breast Cancer Lung Metastasis”
Authors: Culhane Aedín C. , Quackenbush John
Published: March 2024

Abstract
The majority of breast cancer deaths result from metastases rather than from direct effects of the primary tumor itself. Recently, Landemaine and colleagues described a six-gene signature purported to predict lung metastasis risk. They analyzed gene expression in 23 metastases from breast cancer patients (5 lung, 18 non-lung) identifying a 21-gene signature. Expression of 16 of these was analyzed in primary breast tumors from 72 patients with known outcome, and six were selected that were predictive of lung metastases: DSC2, TFCP2L1, UGT8, ITGB8, ANP32E, and FERMT1. Despite the value of such a signature, our analysis indicates that this analysis ignored potentially important confounding factors and that their signature is instead a surrogate for molecular subtype. [Cancer Res 2009;69(18):7480–5]
Data from Melanoma Antigen-11 Inhibits the Hypoxia-Inducible Factor Prolyl Hydroxylase 2 and Activates Hypoxic Response
Authors: Aprelikova Olga , Pandolfi Silvia , Tackett Sean , Ferreira Mark , Salnikow Konstantin , Ward Yvona , Risinger John I. , Barrett J. Carl , Niederhuber John
Published: March 2024

Abstract
Activation of hypoxia-inducible factors (HIF), responsible for tumor angiogenesis and glycolytic switch, is regulated by reduced oxygen availability. Normally, HIF-α proteins are maintained at low levels, controlled by site-specific hydroxylation carried out by HIF prolyl hydroxylases (PHD) and subsequent proteasomal degradation via the von Hippel-Lindau ubiquitin ligase. Using a yeast two-hybrid screen, we identified an interaction between melanoma antigen-11 (MAGE-11) cancer-testis antigen and the major HIF-α hydroxylating enzyme PHD2. The interaction was confirmed by a pull-down assay, coimmunoprecipitation, and colocalization in both normoxic and hypoxic conditions. Furthermore, MAGE-9, the closest homologue of MAGE-11, was also found to interact with PHD2. MAGE-11 inhibited PHD activity without affecting protein levels. This inhibition was accompanied by stabilization of ectopic or endogenous HIF-1α protein. Knockdown of MAGE-11 by small interfering RNA results in decreased hypoxic induction of HIF-1α and its target genes. Inhibition of PHD by MAGE-11, and following activation of HIFs, is a novel tumor-associated HIF regulatory mechanism. This finding provides new insights into the significance of MAGE expression in tumors and may provide valuable tools for therapeutic intervention because of the restricted expression of the MAGE gene family in cancers, but not in normal tissues. [Cancer Res 2009;69(2):616–24]
Data from Promyelocytic Leukemia Protein is Required for Gain of Function by Mutant p53
Authors: Haupt Sue , di Agostino Silvia , Mizrahi Inbal , Alsheich-Bartok Osnat , Voorhoeve Mathijs , Damalas Alex , Blandino Giovanni , Haupt Ygal
Published: March 2024

Abstract
Mutations in the p53 tumor suppressor are the most common genetic events in human cancer. These mutations not only result in a loss of wild-type p53 activity, but can also lead to a gain of new oncogenic properties. Understanding how these gained functions are regulated is in its infancy. In this study, we show that the promyelocytic leukemia (PML) protein is an important regulator of mutant p53. We show that PML interacts with mutant p53. Importantly, PML enhances the transcriptional activity of mutant p53. Unexpectedly, PML is required for the proliferation and colony formation of cancer cells bearing mutant p53. Down-regulation of PML expression inhibits the growth of mutant p53-expressing cancer cells, predominantly by promoting cell cycle arrest. Our results suggest that the tumor suppression function of PML depends on the status of p53. In the context of mutant p53, PML enhances its cancer-promoting activities. [Cancer Res 2009;69(11):4818–26]
Data from High Efficacy of a Listeria-Based Vaccine against Metastatic Breast Cancer Reveals a Dual Mode of Action
Authors: Kim Sun Hee , Castro Francisco , Paterson Yvonne , Gravekamp Claudia
Published: March 2024

Abstract
Most cancer vaccines induce CTL responses to tumor-associated antigens (TAA). Killing of tumor cells occurs through TAA-specific CTL-mediated cytolysis. Here, we show that one preventive followed by two therapeutic immunizations with an attenuated Listeria monocytogenes (LM)–based vaccine eradicates all metastases and almost the entire primary tumor in the syngeneic, aggressive mouse breast tumor model 4T1. We provide strong evidence that this is due to the combined result of direct kill by Listeria infecting the tumor cells and by CTL responses against Listeria antigens. We showed by electron microscopy that LM expressing truncated listeriolysin O (LLO) and amino acid fragments 311 to 660 of TAA Mage-b (LM-LLO-Mage-b311-660) and the control strain LM-LLO infect tumor cells in vitro and in vivo. In vitro data indicate that tumor cell death occurs through activation of NADP+ oxidase and increased intracellular Ca2+ levels, both resulting in the production of high ROS levels. Because both LM-LLO and LM-LLO-Mage-b311-660 showed equally strong efficacies in vivo, we concluded that LM-LLO was crucial and Mage-b was of less importance. We found strong CTL responses to LM-LLO in the spleen, and depletion of CD8 T cells in vivo resulted in significant tumor regrowth (52%) in LM-LLO–vaccinated mice, indicating that LM-LLO–specific CTL indeed partially contributed to tumor cell kill in vivo. This dual mode of action of a Listeria-based vaccine has not been described before and may provide new directions in the development of more effective vaccines against metastatic breast cancer. [Cancer Res 2009;69(14):5860–6]
Data from Phosphoglucose Isomerase/Autocrine Motility Factor Mediates Epithelial and Mesenchymal Phenotype Conversions in Breast Cancer
Authors: Funasaka Tatsuyoshi , Hogan Victor , Raz Avraham
Published: March 2024

Abstract
Phosphoglucose isomerase/autocrine motility factor (PGI/AMF) is a housekeeping gene product/cytokine that catalyzes a step in glycolysis and gluconeogenesis, and acts as a multifunctional cytokine associated with aggressive tumors. PGI/AMF has been correlated significantly with breast cancer progression and poor prognosis in breast cancer. We show here that ectopic expression of PGI/AMF induced epithelial-to-mesenchymal transition (EMT) in MCF10A normal human breast epithelial cells, and inhibition of PGI/AMF expression triggered mesenchymal-to-epithelial transition (MET) in aggressive mesenchymal-type human breast cancer MDA-MB-231 cells. EMT in MCF10A cells was shown by morphologic changes and loss of E-cadherin/β-catenin–mediated cell-cell adhesion, which is concomitant with the induction of the E-cadherin transcriptional repressor Snail and proteosome-dependent degradation of β-catenin protein. Molecular analysis showed that PGI/AMF suppressed epithelial marker expressions and enhanced mesenchymal marker expressions. Silencing of PGI/AMF expression by RNA interference in MDA-MB-231 cells induced the reverse processes of EMT including altered cell shape, gain of epithelial marker, and reduction of mesenchymal marker, e.g., MET. Taken together, the results show the involvement of PGI/AMF in both EMT and MET: overexpression of PGI/AMF induces EMT in normal breast epithelial cells and reduction of PGI/AMF expression led to MET in aggressive breast cancer cells. These results suggest for the first time that PGI/AMF is a key gene to both EMT in the initiating step of cancer metastasis and MET in the later stage of metastasis during breast cancer progression. [Cancer Res 2009;69(13):5349–56]
Data from WWOX Gene Expression Abolishes Ovarian Cancer Tumorigenicity In vivo and Decreases Attachment to Fibronectin via Integrin α3
Authors: Gourley Charlie , Paige Adam J.W. , Taylor Karen J. , Ward Carol , Kuske Barbara , Zhang Jieqing , Sun Mingjun , Janczar Szymon , Harrison David J. , Muir Morwenna , Smyth John F. , Gabra Hani
Published: March 2024

Abstract
The WW domain–containing oxidoreductase (WWOX) gene is located at FRA16D, a common fragile site involved in human cancer. Targeted deletion of Wwox in mice causes increased spontaneous tumor incidence, confirming that WWOX is a bona fide tumor suppressor gene. We show that stable transfection of WWOX into human PEO1 ovarian cancer cells, containing homozygous WWOX deletion, abolishes in vivo tumorigenicity, but this does not correlate with alteration of in vitro growth. Rather, WWOX restoration in PEO1, or WWOX overexpression in SKOV3 ovarian cancer cells, results in reduced attachment and migration on fibronectin, an extracellular matrix component linked to peritoneal metastasis. Conversely, siRNA-mediated knockdown of endogenous WWOX in A2780 ovarian cancer cells increases adhesion to fibronectin. In addition, whereas there is no WWOX-dependent difference in cell death in adherent cells, WWOX-transfected cells in suspension culture display a proapoptotic phenotype. We further show that WWOX expression reduces membranous integrin α3 protein but not integrin α3 mRNA levels, and that adhesion of PEO1 cells to fibronectin is predominantly mediated through integrin α3. We therefore propose that WWOX acts as an ovarian tumor suppressor by modulating the interaction between tumor cells and the extracellular matrix and by inducing apoptosis in detached cells. Consistent with this, the suppression of PEO1 tumorigenicity by WWOX can be partially overcome by implanting these tumor cells in Matrigel. These data suggest a possible role for the loss of WWOX in the peritoneal dissemination of human ovarian cancer cells. [Cancer Res 2009;69(11):4835–42]
Data from Reversal of P-glycoprotein–Mediated Multidrug Resistance by the Murine Double Minute 2 Antagonist Nutlin-3
Authors: Michaelis Martin , Rothweiler Florian , Klassert Denise , von Deimling Andreas , Weber Kristoffer , Fehse Boris , Kammerer Bernd , Doerr Hans Wilhelm , Cinatl Jindrich
Published: March 2024

Abstract
Murine double minute 2 (MDM2) negatively regulates the activity of the tumor suppressor protein p53. Nutlin-3 is a MDM2 inhibitor under preclinical investigation as nongenotoxic activator of the p53 pathway for cancer therapy. Here, nutlin-3 was evaluated for its activity alone or in combination with established chemotherapeutic drugs for antitumor action in chemosensitive and chemoresistant neuroblastoma and rhabdomyosarcoma cell lines. Effects of nutlin-3 single treatment were much more pronounced in p53 wild-type cell lines (IC50s <3 μmol/L) than in p53-mutated cell lines (IC50s >17 μmol/L). In sharp contrast to the expectations, nutlin-3 concentrations that did not affect viability of p53-mutated cell lines strongly increased the efficacy of vincristine in p53-mutated, P-glycoprotein (P-gp)–overexpressing cell lines (decrease in IC50s 92- to 3,434-fold). Similar results were obtained for other P-gp substrates. Moreover, nutlin-3 reduced efflux of rhodamine 123 and other fluorescence dyes that are effluxed by P-gp. Investigation of Madin-Darby canine kidney (MDCK) II cells stably transfected with plasmids encoding for P-gp (MDCKII MDR1) or multidrug resistance protein 1 (MRP-1, MDCKII MRP1) revealed that nutlin-3 not only interferes with P-gp but also affects MRP-1–mediated efflux. Kinetic studies and investigation of P-gp-ATPase activity showed that nutlin-3 is likely to act as a P-gp transport substrate. Examination of the nutlin-3 enantiomers nutlin-3a and nutlin-3b revealed that, in contrast to MDM2-inhibitory activity that is limited to nutlin-3a, both enantiomers similarly interfere with P-gp–mediated drug efflux. In conclusion, nutlin-3–induced inhibition of P-gp and MRP-1 was discovered as a novel anticancer mechanism of the substance in this report. [Cancer Res 2009;69(2):416–21]
Data from Circulating Galectin-3 Promotes Metastasis by Modifying MUC1 Localization on Cancer Cell Surface
Authors: Zhao Qicheng , Guo Xiuli , Nash Gerard B. , Stone Philip C. , Hilkens John , Rhodes Jonathan M. , Yu Lu-Gang
Published: March 2024

Abstract
Adhesion of circulating tumor cells to the blood vessel endothelium is a critical step in cancer metastasis. We show in this study that galectin-3, the concentration of which is greatly increased in the circulation of cancer patients, increases cancer cell adhesion to macrovascular and microvascular endothelial cells under static and flow conditions, increases transendothelial invasion, and decreases the latency of experimental metastasis in athymic mice. These effects of galectin-3 are shown to be a consequence of its interaction with cancer-associated MUC1, which breaks the “protective shield” of the cell-surface MUC1 by causing MUC1 polarization, leading to exposure of smaller cell-surface adhesion molecules/ligands including CD44 and ligand(s) for E-selectin. Thus, the interaction in the bloodstream of cancer patients between circulating galectin-3 and cancer cells expressing MUC1 bearing the galectin-3 ligand TF (Galβ1,3GalNAc-) promotes metastasis. This provides insight into the molecular regulation of metastasis and has important implications for the development of novel therapeutic strategies for prevention of metastasis. [Cancer Res 2009;69(17):6799–806]
Data from Protein Kinase Cδ Activates RelA/p65 and Nuclear Factor-κB Signaling in Response to Tumor Necrosis Factor-α
Authors: Lu Zheng-Guang , Liu Hanshao , Yamaguchi Tomoko , Miki Yoshio , Yoshida Kiyotsugu
Published: March 2024

Abstract
Nuclear factor-κB (NF-κB) is tightly modulated by IκB kinases and IκBα in the cytoplasm. On stimulation, NF-κB translocates into the nucleus to initiate transcription; however, regulation of its transcriptional activity remains obscure. Here, we show that protein kinase C (PKC) δ controls the main subunit of NF-κB, RelA/p65. On exposure to tumor necrosis factor-α (TNF-α), the expression of RelA/p65 target genes such as IκBα, RelB, and p100/p52 is up-regulated in a PKCδ-dependent manner. The results also show that PKCδ is targeted to the nucleus and forms a complex with RelA/p65 following TNF-α exposure. Importantly, kinase activity of PKCδ is required for RelA/p65 transactivation. In concert with these results, PKCδ activates RelA/p65 for its occupancy to target-gene promoters, including IκBα and p100/p52. Moreover, functional analyses show that inhibition of PKCδ is associated with substantial attenuation of NF-κB activity in response to TNF-α. These findings provide evidence that PKCδ orchestrates RelA/p65 transactivation, a requisite for NF-κB signaling pathway in the nucleus. [Cancer Res 2009;69(14):5927–35]
Data from Tumor Vaccines Expressing Flt3 Ligand Synergize with CTLA-4 Blockade to Reject Preimplanted Tumors
Authors: Curran Michael A. , Allison James P.
Published: March 2024

Abstract
The transformation of a healthy cell into a malignant neoplasm involves numerous genetic mutations and aberrations in gene expression. As few of these changes are shared between individuals or types of cancer, the best source for eliciting broad-spectrum tumor immunity remains each patient's own tumor. Previously, we have shown that combining blockade of the T-cell–negative costimulatory molecule CTL-associated antigen 4 (CTLA-4) and vaccination with irradiated B16 tumor expressing granulocyte macrophage colony-stimulating factor (GM-CSF; Gvax) promotes rejection of established murine melanomas. Here we show that, like GM-CSF, the cytokine Flt3 ligand (Flt3L) expressed in B16 and coupled with CTLA-4 blockade promotes both prophylactic and therapeutic rejection of B16. When administered at the site of growing tumor, Gvax fails to prevent tumor outgrowth in any mice, whereas the B16-Flt3L vaccine (Fl3vax) induces the rejection of 75% of melanomas implanted 3 days before vaccination. Relative to Gvax, Fl3vax promotes greater infiltration of both the vaccine site and the tumor site by CD8+ T cells and “sentinel” and plasmacytoid dendritic cells. Gvax and Fl3vax did not synergize when used in combination in treating B16 melanoma even in the context of CD25+ regulatory T-cell depletion. Further, we show that a combination of Flt3L expression and CTLA-4 blockade can also promote the rejection of established TRAMP prostate adenocarcinomas, proving that the utility of this treatment extends beyond melanoma. Engineering Flt3L to be constitutively secreted and attaching an IgG2a tail yielded a B16 vaccine that, when combined with CTLA-4 blockade, prevented the outgrowth of significantly more 5-day implanted B16-BL6 tumors than did Gvax. [Cancer Res 2009;69(19):7747–55]
Data from Cancer Vaccine Enhanced, Non–Tumor-Reactive CD8+ T Cells Exhibit a Distinct Molecular Program Associated with “Division Arrest Anergy”
Authors: Beyer Marc , Karbach Julia , Mallmann Michael R. , Zander Thomas , Eggle Daniela , Classen Sabine , Debey-Pascher Svenja , Famulok Michael , Jäger Elke , Schultze Joachim L.
Published: March 2024

Abstract
Immune-mediated tumor rejection relies on fully functional T-cell responses and neutralization of an adverse tumor microenvironment. In clinical trials, we detected peptide-specific but non–tumor-reactive and therefore not fully functional CD8+ T cells post-vaccination against tumor antigens. Understanding the molecular mechanisms behind nontumor reactivity will be a prerequisite to overcome this CD8+ T-cell deviation. We report that these non–tumor-reactive CD8+ T cells are characterized by a molecular program associated with hallmarks of “division arrest anergy.” Non–tumor-reactive CD8+ T cells are characterized by coexpression of CD7, CD25, and CD69 as well as elevated levels of lckp505 and p27kip1. In vivo quantification revealed high prevalence of non–tumor-reactive CD8+ T cells with increased levels during cancer vaccination. Furthermore, their presence was associated with a trend toward shorter survival. Dynamics and frequencies of non–target-reactive CD8+ T cells need to be further addressed in context of therapeutic vaccine development in cancer, chronic infections, and autoimmune diseases. [Cancer Res 2009;69(10):4346–54]
Data from Heregulin Regulates Prolactinoma Gene Expression
Authors: Vlotides George , Cooper Odelia , Chen Yen-Hao , Ren Song-Guang , Greenman Yona , Melmed Shlomo
Published: March 2024

Abstract
To investigate the role of p185her2/neu/ErbB3 signaling in pituitary tumor function, we examined these receptors in human prolactinomas. Immunofluorescent p185her2/neu was detected in almost all (seven of eight), and ErbB3 expression in a subset (four of eight) of tumors (seven adenomas and one carcinoma). Quantitative PCR also showed abundant ErbB3 mRNA in tumor specimens derived from a rarely encountered prolactin-cell carcinoma. Activation of p185c-neu/ErbB3 signaling with heregulin, the ErbB3 ligand, in rat lacto-somatotroph (GH4C1) tumor cells specifically induced prolactin (PRL) mRNA expression ∼5-fold and PRL secretion ∼4-fold, whereas growth hormone expression was unchanged. Heregulin (6 nmol/L) induced tyrosine phosphorylation and ErbB3 and p185c-neu heterodimerization, with subsequent activation of intracellular ERK and Akt. The Akt signal was specific to ErbB3 activation by heregulin, and was not observed in response to epidermal growth factor activation of epidermal growth factor receptor. Gefitinib, the tyrosine kinase inhibitor, suppressed heregulin-mediated p185c-neu/ErbB3 signaling to PRL. Heregulin induction of PRL was also abrogated by transfecting cells with short interfering RNA directed against ErbB3. Pharmacologic inhibition of heregulin-induced phosphoinositide-3-kinase/Akt (with LY294002) and ERK (with U0126) signaling, as well as short interfering RNA–mediated mitogen-activated protein kinase-1 down-regulation, showed ERK signaling as the primary transducer of heregulin signaling to PRL. These results show ErbB3 expression in human prolactinomas and a novel ErbB3-mediated mechanism for PRL regulation in experimental lactotroph tumors. Targeted inhibition of up-regulated p185c-neu/ErbB3 activity could be useful for the treatment of aggressive prolactinomas resistant to conventional therapy. [Cancer Res 2009;69(10):4209–16]
Data from Chemical Genomics Identifies the Unfolded Protein Response as a Target for Selective Cancer Cell Killing during Glucose Deprivation
Authors: Saito Sakae , Furuno Aki , Sakurai Junko , Sakamoto Asami , Park Hae-Ryong , Shin-ya Kazuo , Tsuruo Takashi , Tomida Akihiro
Published: March 2024

Abstract
Glucose deprivation, a cell condition that occurs in solid tumors, activates the unfolded protein response (UPR). A key feature of the UPR is the transcription program activation, which allows the cell to survive under stress conditions. Here, we show that the UPR transcription program is disrupted by the antidiabetic biguanides metformin, buformin, and phenformin depending on cellular glucose availability. These drugs inhibit production of the UPR transcription activators XBP1 and ATF4 and induce massive cell death during glucose deprivation as did the antitumor macrocyclic compound versipelostatin. Gene expression profiling shows remarkable similarity in the modes of action of biguanides and versipelostatin determined by the broad range of glucose deprivation-inducible genes. Importantly, during glucose deprivation, most of the biguanide suppression genes overlap with the genes induced by tunicamycin, a chemical UPR inducer. Gene expression profiling also identifies drug-driven signatures as a tool for discovering pharmacologic UPR modulators. Our findings show that disrupting the UPR during glucose deprivation could be an attractive approach for selective cancer cell killing and could provide a chemical genomic basis for developing UPR-targeting drugs against solid tumors. [Cancer Res 2009;69(10):4225–34]
Data from Quantitative Metrics of Net Proliferation and Invasion Link Biological Aggressiveness Assessed by MRI with Hypoxia Assessed by FMISO-PET in Newly Diagnosed Glioblastomas
Authors: Szeto Mindy D. , Chakraborty Gargi , Hadley Jennifer , Rockne Russ , Muzi Mark , Alvord Ellsworth C. , Krohn Kenneth A. , Spence Alexander M. , Swanson Kristin R.
Published: March 2024

Abstract
Glioblastoma multiforme (GBM) are aggressive and uniformly fatal primary brain tumors characterized by their diffuse invasion of the normal-appearing parenchyma peripheral to the clinical imaging abnormality. Hypoxia, a hallmark of aggressive tumor behavior often noted in GBMs, has been associated with resistance to therapy, poorer survival, and more malignant tumor phenotypes. Based on the existence of a set of novel imaging techniques and modeling tools, our objective was to assess a hypothesized quantitative link between tumor growth kinetics [assessed via mathematical models and routine magnetic resonance imaging (MRI)] and the hypoxic burden of the tumor [assessed via positron emission tomography (PET) imaging]. Our biomathematical model for glioma kinetics describes the spatial and temporal evolution of a glioma in terms of concentration of malignant tumor cells. This model has already been proven useful as a novel tool to dynamically quantify the net rates of proliferation (ρ) and invasion (D) of the glioma cells in individual patients. Estimates of these kinetic rates can be calculated from routinely available pretreatment MRI in vivo. Eleven adults with GBM were imaged preoperatively with 18F-fluoromisonidazole (FMISO)–PET and serial gadolinium-enhanced T1- and T2-weighted MRIs to allow the estimation of patient-specific net rates of proliferation (ρ) and invasion (D). Hypoxic volumes were quantified from each FMISO-PET scan following standard techniques. To control for tumor size variability, two measures of hypoxic burden were considered: relative hypoxia (RH), defined as the ratio of the hypoxic volume to the T2-defined tumor volume, and the mean intensity on FMISO-PET scaled to the blood activity of the tracer (mean T/B). Pearson correlations between RH and the net rate of cell proliferation (ρ) reached significance (P < 0.04). Moreover, highly significant positive correlations were found between biological aggressiveness ratio (ρ/D) and both RH (P < 0.00003) and the mean T/B (P < 0.0007). [Cancer Res 2009;69(10):4502–9]

Major Findings

Overall, biological aggressiveness assessed by serial MRI is linked with hypoxic burden assessed on FMISO-PET using a novel biomathematical model for glioma growth and invasion. This study suggests that patient-specific modeling of growth kinetics can provide novel and valuable insight into the quantitative connections between disparate information provided by multimodality imaging.
Data from Activation of Src by Protein Tyrosine Phosphatase 1B Is Required for ErbB2 Transformation of Human Breast Epithelial Cells
Authors: Arias-Romero Luis E. , Saha Sayanti , Villamar-Cruz Olga , Yip Shu-Chin , Ethier Stephen P. , Zhang Zhong-Yin , Chernoff Jonathan
Published: March 2024

Abstract
Protein tyrosine phosphatase (PTP) 1B plays a major role in inhibiting signaling from the insulin and leptin receptors. Recently, PTP1B was found to have an unexpected positive role in ErbB2 signaling in a mouse model of breast cancer, but the mechanism underlying this effect has been unclear. Using human breast epithelial cells grown in a three-dimensional matrix, we found that PTP1B, but not the closely related enzyme T-cell PTP, is required for ErbB2 transformation in vitro. Activation of ErbB2, but not ErbB1, increases PTP1B expression, and increased expression of PTP1B activates Src and induces a Src-dependent transformed phenotype. These findings identify a molecular mechanism by which PTP1B links an important oncogenic receptor tyrosine kinase to signaling pathways that promote aberrant cell division and survival in human breast epithelial cells. [Cancer Res 2009;69(11):4582–8]
Data from Epithelial-to-Mesenchymal Transition and Resistance to Ingenol 3-Angelate, a Novel Protein Kinase C Modulator, in Colon Cancer Cells
Authors: Ghoul Aïda , Serova Maria , Astorgues-Xerri Lucile , Bieche Ivan , Bousquet Guilhem , Varna Mariana , Vidaud Michel , Phillips Edelmira , Weill Sophie , Benhadji Karim A. , Lokiec François , Cvitkovic Esteban , Faivre Sandrine , Raymond Eric
Published: March 2024

Abstract
Acquired resistance to protein kinase C (PKC) modulators may explain the failure of clinical trials in patients with cancer. Herein, we established a human colon cancer cell line resistant to PEP005, a drug that inhibits PKCα and activates PKCδ. Colo205-R cells, selected by stepwise exposure to PEP005, were >300-fold more resistant to PEP005 than parental Colo205-S cells and were cross-resistant to phorbol 12-myristate 13-acetate, bryostatin, bistratene A, and staurosporine. No PKCα or PKCδ mutation was detected in Colo205-S and Colo205-R cells. Changes in Colo205-R cells were reminiscent of the epithelial-to-mesenchymal transition (EMT) phenotype. Accordingly, Colo205-R cells were more invasive than Colo205-S in Matrigel assays and in mouse xenografts. We also found an increased mRNA expression of several EMT genes, such as those encoding for transforming growth factor-β and vimentin, along with a decreased mRNA expression of genes involved in epithelial differentiation, such as CDH1 (E-cadherin), CLDN4 (claudin 4), S100A4, and MUC1, in Colo205-R compared with Colo205-S cells in vitro and in vivo. Interestingly, high expression of ET-1 was shown in Colo205-R cells and correlated with low sensitivity to PEP005 and staurosporine in a panel of 10 human cancer cell lines. Inhibition of the ET-1 receptor ETR-A with bosentan restored the antiproliferative effects of PEP005 in Colo205-R cells and decreased the invasive properties of this cell line. Exogenous exposure to ET-1 and silencing ET-1 expression using small interfering RNA modulated cell signaling in Colo205-S and Colo205-R. In summary, acquired resistance to PEP005 was associated with expression of EMT markers and activates the ET-1/ETR-A cell signaling. [Cancer Res 2009;69(10):4260–69]
Data from Biological Significance of Prolactin in Gynecologic Cancers
Authors: Levina Vera V. , Nolen Brian , Su YunYun , Godwin Andrew K. , Fishman David , Liu Jinsong , Mor Gil , Maxwell Larry G. , Herberman Ronald B. , Szczepanski Miroslaw J. , Szajnik Marta E. , Gorelik Elieser , Lokshin Anna E.
Published: March 2024

Abstract
There is increasing evidence that prolactin (PRL), a hormone/cytokine, plays a role in breast, prostate, and colorectal cancers via local production or accumulation. Elevated levels of serum PRL in ovarian and endometrial cancers have been reported, indicating a potential role for PRL in endometrial and ovarian carcinogenesis. In this study, we show that serum PRL levels are significantly elevated in women with a strong family history of ovarian cancer. We show dramatically increased expression of PRL receptor in ovarian and endometrial tumors as well as in endometrial hyperplasia, signifying the importance of PRL signaling in malignant and premalignant conditions. PRL mRNA was expressed in ovarian and endometrial tumors, indicating the presence of an autocrine loop. PRL potently induced proliferation in several ovarian and endometrial cancer cell lines. Binding of PRL to its receptor was followed by rapid phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, mitogen-activated protein kinase/ERK kinase 1, signal transducer and activator of transcription 3, CREB, ATF-2, and p53 and activation of 37 transcription factors in ovarian and endometrial carcinoma cells. PRL also activated Ras oncogene in these cells. When human immortalized normal ovarian epithelial cells were chronically exposed to PRL, a malignant transformation occurred manifested by the acquired ability of transformed cells to form clones, grow in soft agar, and form tumors in severe combined immunodeficient-beige mice. Transformation efficiency was diminished by a Ras inhibitor, providing proof that PRL-induced transformation uses the Ras pathway. In summary, we present findings that indicate an important role for PRL in ovarian and endometrial tumorigenesis. PRL may represent a risk factor for ovarian and endometrial cancers. [Cancer Res 2009;69(12):5226–33]
Data from Stepwise DNA Methylation Changes Are Linked to Escape from Defined Proliferation Barriers and Mammary Epithelial Cell Immortalization
Authors: Novak Petr , Jensen Taylor J. , Garbe James C. , Stampfer Martha R. , Futscher Bernard W.
Published: March 2024

Abstract
The timing and progression of DNA methylation changes during carcinogenesis are not completely understood. To develop a timeline of aberrant DNA methylation events during malignant transformation, we analyzed genome-wide DNA methylation patterns in an isogenic human mammary epithelial cell (HMEC) culture model of transformation. To acquire immortality and malignancy, the cultured finite lifespan HMEC must overcome two distinct proliferation barriers. The first barrier, stasis, is mediated by the retinoblastoma protein and can be overcome by loss of p16INK4A expression. HMEC that escape stasis and continue to proliferate become genomically unstable before encountering a second more stringent proliferation barrier, telomere dysfunction due to telomere attrition. Rare cells that acquire telomerase expression may escape this barrier, become immortal, and develop further malignant properties. Our analysis of HMEC transitioning from finite lifespan to malignantly transformed showed that aberrant DNA methylation changes occur in a stepwise fashion early in the transformation process. The first aberrant DNA methylation step coincides with overcoming stasis, and results in few to hundreds of changes, depending on how stasis was overcome. A second step coincides with immortalization and results in hundreds of additional DNA methylation changes regardless of the immortalization pathway. A majority of these DNA methylation changes are also found in malignant breast cancer cells. These results show that large-scale epigenetic remodeling occurs in the earliest steps of mammary carcinogenesis, temporally links DNA methylation changes and overcoming cellular proliferation barriers, and provides a bank of potential epigenetic biomarkers that may prove useful in breast cancer risk assessment. [Cancer Res 2009;69(12):5251–8]
Data from Genome-Wide Identification of Direct Target Genes Implicates Estrogen-Related Receptor α as a Determinant of Breast Cancer Heterogeneity
Authors: Deblois Geneviève , Hall Jacqueline A. , Perry Marie-Claude , Laganière Josée , Ghahremani Majid , Park Morag , Hallett Michael , Giguère Vincent
Published: March 2024

Abstract
Estrogen-related receptor α (ERRα) is an orphan nuclear receptor, the expression of which correlates with negative prognosis in breast cancer. ERRα shares functional features with the estrogen receptor α (ERα) and its activity is modulated by the ERBB2 signaling pathway. Using genome-wide binding sites location analyses in ERα-positive and ERα-negative breast cancer cell lines, we show that ERRα and ERα display strict binding site specificity and maintain independent mechanisms of transcriptional activation. Nonetheless, ERRα and ERα coregulate a small subset of common target genes via binding either to a dual-specificity binding site or to distinct cognate binding sites located within the extended promoter region of the gene. Although ERRα signaling in breast cancer cells is mostly independent of ERα, the small fraction of common ERRα/ERα targets comprises genes with high relevance to breast tumor biology, including genes located within the ERBB2 amplicon and GATA3. Finally, unsupervised hierarchical clustering based on the expression profiling of ERRα direct target genes in human breast tumors revealed four main clusters that recapitulate established tumor subtypes. Taken together, the identification and functional characterization of the ERRα transcriptional network implicate ERRα signaling as a determinant of breast cancer heterogeneity. [Cancer Res 2009;69(15):6149–57]
Data from Nanoparticle-Delivered Suicide Gene Therapy Effectively Reduces Ovarian Tumor Burden in Mice
Authors: Huang Yu-Hung , Zugates Gregory T. , Peng Weidan , Holtz David , Dunton Charles , Green Jordan J. , Hossain Naushad , Chernick Michael R. , Padera Robert F. , Langer Robert , Anderson Daniel G. , Sawicki Janet A.
Published: March 2024

Abstract
There is currently no effective therapy for patients with advanced ovarian cancer. To address the need for a more effective treatment for this deadly disease, we conducted preclinical tests in ovarian tumor–bearing mice to evaluate the therapeutic efficacy of using a cationic biodegradable poly(β-amino ester) polymer as a vector for nanoparticulate delivery of DNA encoding a diphtheria toxin suicide protein (DT-A). The promoter sequences of two genes that are highly active in ovarian tumor cells, MSLN and HE4, were used to target DT-A expression to tumor cells. Administration of DT-A nanoparticles directly to s.c. xenograft tumors and to the peritoneal cavity of mice bearing primary and metastatic ovarian tumors resulted in a significant reduction in tumor mass and a prolonged life span compared to control mice. Minimal nonspecific tissue and blood chemistry toxicity was observed following extended treatment with nanoparticles. DT-A nanoparticle therapy suppressed tumor growth more effectively than treatment with clinically relevant doses of cisplatin and paclitaxel. Our findings suggest that i.p. administration of polymeric nanoparticles to deliver DT-A encoding DNA, combined with transcriptional regulation to target gene expression to ovarian tumor cells, holds promise as an effective therapy for advanced-stage ovarian cancer. [Cancer Res 2009;69(15):6184–91]
Data from A Double Hit to Kill Tumor and Endothelial Cells by TRAIL and Antiangiogenic 3TSR
Authors: Ren Bin , Song Keli , Parangi Sareh , Jin Taiguang , Ye Min , Humphreys Robin , Duquette Mark , Zhang Xuefeng , Benhaga Nordine , Lawler Jack , Khosravi-Far Roya
Published: March 2024

Abstract
As tumor development relies on a coordination of angiogenesis and tumor growth, an efficient antitumor strategy should target both the tumor and its associated vessels. Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) induces apoptosis in a tumor-selective manner. Additionally, thrombospondin-1, a naturally occurring inhibitor of angiogenesis, and a recombinant protein containing functional domains of thrombospondin-1, 3TSR, have been shown to be necessary and sufficient to inhibit tumor angiogenesis. Here, we show that a combination of a TRAIL receptor 2 agonist antibody, Lexatumumab, and 3TSR results in a significantly enhanced and durable tumor inhibition. We further observed that 3TSR induces apoptosis in primary endothelial cells by up-regulating the expression of TRAIL receptors 1 and 2 in a CD36 and Jun NH2-terminal kinase-dependent manner leading to the activation of both intrinsic and extrinsic apoptotic machineries. The modulation of these pathways is critical for 3TSR-induced apoptosis as disrupting either via specific inhibitors reduced apoptosis. Moreover, 3TSR attenuates the Akt survival pathway. These studies indicate that 3TSR plays a critical role in regulating the proapoptotic signaling pathways that control growth and death in endothelial cells and that a combination of TRAIL and 3TSR acts as a double hit against tumor and tumor-associated vessels. [Cancer Res 2009;69(9):3856–65]
Data from Connective Tissue Growth Factor Confers Drug Resistance in Breast Cancer through Concomitant Up-regulation of Bcl-xL and cIAP1
Authors: Wang Ming-Yang , Chen Pai-Sheng , Prakash Ekambaranellore , Hsu Hsing-Chih , Huang Hsin-Yi , Lin Ming-Tsan , Chang King-Jen , Kuo Min-Liang
Published: March 2024

Abstract
Connective tissue growth factor (CTGF) expression is elevated in advanced breast cancer and promotes metastasis. Chemotherapy response is only transient in most metastatic diseases. In the present study, we examined whether CTGF expression could confer drug resistance in human breast cancer. In breast cancer patients who received neoadjuvant chemotherapy, CTGF expression was inversely associated with chemotherapy response. Overexpression of CTGF in MCF7 cells (MCF7/CTGF) enhanced clonogenic ability, cell viability, and resistance to apoptosis on exposure to doxorubicin and paclitaxel. Reducing the CTGF level in MDA-MB-231 (MDA231) cells by antisense CTGF cDNA (MDA231/AS cells) mitigated this drug resistance capacity. CTGF overexpression resulted in resistance to doxorubicin- and paclitaxel-induced apoptosis by up-regulation of Bcl-xL and cellular inhibitor of apoptosis protein 1 (cIAP1). Knockdown of Bcl-xL or cIAP1 with specific small interfering RNAs abolished the CTGF-mediated resistance to apoptosis induced by the chemotherapeutic agents in MCF7/CTGF cells. Inhibition of extracellular signal–regulated kinase (ERK)-1/2 effectively reversed the resistance to apoptosis as well as the up-regulation of Bcl-xL and cIAP1 in MCF7/CTGF cells. A neutralizing antibody against integrin αvβ3 significantly attenuated CTGF-mediated ERK1/2 activation and up-regulation of Bcl-xL and cIAP1, indicating that the integrin αvβ3/ERK1/2 signaling pathway is essential for CTGF functions. The Bcl-xL level also correlated with the CTGF level in breast cancer patients. We also found that a COOH-terminal domain peptide from CTGF could exert activities similar to full-length CTGF, in activation of ERK1/2, up-regulation of Bcl-xL/cIAP1, and resistance to apoptosis. We conclude that CTGF expression could confer resistance to chemotherapeutic agents through augmenting a survival pathway through ERK1/2-dependent Bcl-xL/cIAP1 up-regulation. [Cancer Res 2009;69(8):3482–91]
Data from Modulation of Caspase-Independent Cell Death Leads to Resensitization of Imatinib Mesylate–Resistant Cells
Authors: Lavallard Vanessa J. , Pradelli Ludivine A. , Paul Audrey , Bénéteau Marie , Jacquel Arnaud , Auberger Patrick , Ricci Jean-Ehrland
Published: March 2024

Abstract
Imatinib mesylate is widely used for the treatment of patients with chronic myelogenous leukemia (CML). This compound is very efficient in killing Bcr-Abl–positive cells in a caspase-dependent manner. Nevertheless, several lines of evidence indicated that caspase-mediated cell death (i.e., apoptosis) is not the only type of death induced by imatinib. The goal of our study was to evaluate the importance of the newly described caspase-independent cell death (CID) in Bcr-Abl–positive cells. We established in several CML cell lines that imatinib, in conjunction with apoptosis, also induced CID. CID was shown to be as efficient as apoptosis in preventing CML cell proliferation and survival. We next investigated the potential implication of a recently identified mechanism used by cancer cells to escape CID through overexpression of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). We showed here, in several CML cell lines, that GAPDH overexpression was sufficient to induce protection from CID. Furthermore, imatinib-resistant Bcr-Abl–positive cell lines were found to spontaneously overexpress GAPDH. Finally, we showed that a GAPDH partial knockdown, using specific short hairpin RNAs, was sufficient to resensitize those resistant cells to imatinib-induced cell death. Taken together, our results indicate that CID is an important effector of imatinib-mediated cell death. We also established that GAPDH overexpression can be found in imatinib-resistant Bcr-Abl–positive cells and that its down-regulation can resensitize those resistant cells to imatinib-induced death. Therefore, drugs able to modulate GAPDH administered together with imatinib could find some therapeutic benefits in CML patients. [Cancer Res 2009;69(7):3013–20]
Data from Antitumor Efficacy of the Novel RAF Inhibitor GDC-0879 Is Predicted by BRAFV600E Mutational Status and Sustained Extracellular Signal-Regulated Kinase/Mitogen-Activated Protein Kinase Pathway Suppression
Authors: Hoeflich Klaus P. , Herter Sylvia , Tien Janet , Wong Leo , Berry Leanne , Chan Jocelyn , O'Brien Carol , Modrusan Zora , Seshagiri Somasekar , Lackner Mark , Stern Howard , Choo Edna , Murray Lesley , Friedman Lori S. , Belvin Marcia
Published: March 2024

Abstract
Oncogenic activation of the BRAF serine/threonine kinase has been associated with initiation and maintenance of melanoma tumors. As such, development of pharmacologic agents to target RAF proteins or their effector kinases is an area of intense investigation. Here we report the biological properties of GDC-0879, a highly selective, potent, and orally bioavailable RAF small-molecule inhibitor. We used extracellular signal-regulated kinase (ERK)-1/2 and mitogen-activated protein kinase/ERK kinase (MEK)-1/2 phosphorylation as biomarkers to explore the relationship between tumor outcome and pharmacodynamic inhibition of the RAF-MEK-ERK pathway. In GDC-0879–treated mice, both cell line– and patient-derived BRAFV600E tumors exhibited stronger and more sustained pharmacodynamic inhibition (>90% for 8 hours) and improved survival compared with mutant KRAS–expressing tumors. Despite the involvement of activated RAF signaling in RAS-induced tumorigenesis, decreased time to progression was observed for some KRAS-mutant tumors following GDC-0879 administration. Moreover, striking differences were noted for RAF and MEK inhibition across a panel of 130 tumor cell lines. Whereas GDC-0879–mediated efficacy was associated strictly with BRAFV600E status, MEK inhibition also attenuated proliferation and tumor growth of cell lines expressing wild-type BRAF (81% KRAS mutant, 38% KRAS wild type). The responsiveness of BRAFV600E melanoma cells to GDC-0879 could be dramatically altered by pharmacologic and genetic modulation of phosphatidylinositol 3-kinase pathway activity. These data suggest that GDC-0879–induced signaling changes are dependent on the point of oncogenic activation within the RAS network. Taken together, these studies increase our understanding of the molecular determinants for antitumor efficacy resulting from RAF pathway inhibition and have implications for therapeutic intervention in the clinic. [Cancer Res 2009;69(7):3042–51]