bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Direct Inhibition of Elastase Activity by Indole-3-Carbinol Triggers a CD40-TRAF Regulatory Cascade That Disrupts NF-κB Transcriptional Activity in Human Breast Cancer Cells
Authors: Aronchik Ida , Bjeldanes Leonard F. , Firestone Gary L.
Published: March 2023

Abstract
Treatment of highly tumorigenic MDA-MB-231 human breast cancer cells with indole-3-carbinol (I3C) directly inhibited the extracellular elastase-dependent cleavage of membrane-associated CD40, a member of the tumor necrosis factor (TNF) receptor superfamily. CD40 signaling has been implicated in regulating cell survival, apoptosis, and proliferation, as well as in sensitizing breast cancer cells to chemotherapy, and is therefore an important potential target of novel breast cancer treatments. The I3C-dependent accumulation of full-length unprocessed CD40 protein caused a shift in CD40 signaling through TNF receptor–associated factors (TRAF), including the TRAF1/TRAF2 positive regulators and TRAF3 negative regulator of NF-κB transcription factor activity. Because TRAF1 is a transcriptional target gene of NF-κB, I3C disrupted a positive feedback loop involving these critical cell survival components. siRNA ablation of elastase expression mimicked the I3C inhibition of CD40 protein processing and G1 cell cycle arrest, whereas siRNA knockdown of TRAF3 and the NF-κB inhibitor IκB prevented the I3C-induced cell cycle arrest. In contrast, siRNA knockdown of PTEN had no effect on the I3C control of NF-κB activity, showing the importance of CD40 signaling in regulating this transcription factor. Our study provides the first direct in vitro evidence that I3C directly inhibits the elastase-mediated proteolytic processing of CD40, which alters downstream signaling to disrupt NF-κB–induced cell survival and proliferative responses. Furthermore, we have established a new I3C-mediated antiproliferative cascade that has significant therapeutic potential for treatment of human cancers associated with high levels of elastase and its CD40 membrane substrate. Cancer Res; 70(12); 4961–71. ©2010 AACR.
Data from Molecular Causes for BUBR1 Dysfunction in the Human Cancer Predisposition Syndrome Mosaic Variegated Aneuploidy
Authors: Suijkerbuijk Saskia J.E. , van Osch Maria H.J. , Bos Frank L. , Hanks Sandra , Rahman Nazneen , Kops Geert J.P.L.
Published: March 2023

Abstract
Genetic mutations in the mitotic regulatory kinase BUBR1 are associated with the cancer-susceptible disorder mosaic variegated aneuploidy (MVA). In patients with biallelic mutations, a missense mutation pairs with a truncating mutation. Here, we show that cell lines derived from MVA patients with biallelic mutations have an impaired mitotic checkpoint, chromosome alignment defects, and low overall BUBR1 abundance. Ectopic expression of BUBR1 restored mitotic checkpoint activity, proving that BUBR1 dysfunction causes chromosome segregation errors in the patients. Combined analysis of patient cells and functional protein replacement shows that all MVA mutations fall in two distinct classes: those that impose specific defects in checkpoint activity or microtubule attachment and those that lower BUBR1 protein abundance. Low protein abundance is the direct result of the absence of transcripts from truncating mutants combined with high protein turnover of missense mutants. In this group of missense mutants, the amino acid change consistently occurs in or near the BUBR1 kinase domain. Our findings provide a molecular explanation for chromosomal instability in patients with biallelic genetic mutations in BUBR1. Cancer Res; 70(12); 4891–900. ©2010 AACR.
Data from Deficiency in p53 but not Retinoblastoma Induces the Transformation of Mesenchymal Stem Cells In vitro and Initiates Leiomyosarcoma In vivo
Authors: Rubio Ruth , García-Castro Javier , Gutiérrez-Aranda Iván , Paramio Jesús , Santos Mirentxu , Catalina Purificación , Leone Paola E. , Menendez Pablo , Rodríguez René
Published: March 2023

Abstract
Sarcomas have been modeled in mice by the expression of specific fusion genes in mesenchymal stem cells (MSC), supporting the concept that MSCs might be the target initiating cell in sarcoma. In this study, we evaluated the potential oncogenic effects of p53 and/or retinoblastoma (Rb) deficiency in MSC transformation and sarcomagenesis. We derived wild-type, p53−/−, Rb−/−, and p53−/−Rb−/− MSC cultures and fully characterized their in vitro growth properties and in vivo tumorigenesis capabilities. In contrast with wild-type MSCs, Rb−/−, p53−/−, and p53−/−Rb−/− MSCs underwent in vitro transformation and showed severe alterations in culture homeostasis. More importantly, p53−/− and p53−/−Rb−/− MSCs, but not Rb−/− MSCs, were capable of tumor development in vivo after injection into immunodeficient mice. p53−/− or p53−/−Rb−/− MSCs originated leiomyosarcoma-like tumors, linking this type of smooth muscle sarcoma to p53 deficiency in fat tissue–derived MSCs. Sca1+ and Sca1 low/− cell populations isolated from ex vivo–established, transformed MSC lines from p53−/−Rb−/− tumors showed identical sarcomagenesis potential, with 100% tumor penetrance and identical latency, tumor weight, and histologic profile. Our findings define the differential roles of p53 and Rb in MSC transformation and offer proof-of-principle that MSCs could provide useful tools to dissect the sarcoma pathogenesis. Cancer Res; 70(10); 4185–94. ©2010 AACR.
Data from ARF Suppresses Tumor Angiogenesis through Translational Control of VEGFA mRNA
Authors: Kawagishi Hiroyuki , Nakamura Hideaki , Maruyama Mitsuo , Mizutani Shuki , Sugimoto Kazushi , Takagi Masatoshi , Sugimoto Masataka
Published: March 2023

Abstract
Vascular endothelial growth factor A (VEGFA) is a specific mitogen for vascular endothelial cells that plays a critical role in cancer neoangiogenesis. Here, we report that the nucleolar tumor suppressor p19ARF suppresses VEGFA expression, acting at the level of mRNA translation without affecting the transcription of the VEGFA gene. Translational repression of VEGFA mRNA by p19ARF does not require p53, a major target of the ARF tumor suppressor pathway, but instead correlates with binding to nucleophosmin/B23. Maintaining VEGFA expression relies on nucleophosmin/B23, and downregulating this protein by RNAi or p19ARF leads to translational repression of VEGFA. p19ARF inhibits VEGFA-dependent tumor angiogenesis in nude mice. Additionally, p14ARF expression and microvessel density are inversely correlated in human colon carcinomas. Taken together, our results define a mechanism by which the ARF tumor suppressor targets the translational repression of specific oncogenes during neoplastic transformation. Cancer Res; 70(11); 4749–58. ©2010 AACR.
Data from Central Role of IFNγ–Indoleamine 2,3-Dioxygenase Axis in Regulation of Interleukin-12–Mediated Antitumor Immunity
Authors: Gu Tao , Rowswell-Turner Rachael B. , Kilinc Mehmet O. , Egilmez Nejat K.
Published: March 2023

Abstract
Sustained intratumoral delivery of interleukin-12 (IL-12) and granulocyte macrophage colony-stimulating factor induces tumor regression via restoration of tumor-resident CD8+ T-effector/memory cell cytotoxicity and subsequent repriming of a secondary CD8+ T-effector cell response in tumor-draining lymph nodes (TDLN). However, treatment-induced T-effector activity is transient and is accompanied with a CD4+ CD25+ Foxp3+ T-suppressor cell rebound. Molecular and cellular changes in posttherapy tumor microenvironment and TDLN were monitored to elucidate the mechanism of counterregulation. Real-time PCR analysis revealed a 5-fold enhancement of indoleamine 2,3-dioxygenase (IDO) expression in the tumor and the TDLN after treatment. IDO induction required IFNγ and persisted for up to 7 days. Administration of the IDO inhibitor d-1-methyl tryptophan concurrent with treatment resulted in a dramatic enhancement of tumor regression. Enhanced efficacy was associated with a diminished T-suppressor cell rebound, revealing a link between IDO activity and posttherapy regulation. Further analysis established that abrogation of the regulatory counterresponse resulted in a 10-fold increase in the intratumoral CD8+ T-cell to CD4+ Foxp3+ T-cell ratio. The ratio of proliferating CD8+ T-effector to CD4+ Foxp3+ T-suppressor cells was prognostic for efficacy of tumor suppression in individual mice. IFNγ-dependent IDO induction and T-suppressor cell expansion were primarily driven by IL-12. These findings show a critical role for IDO in the regulation of IL-12–mediated antitumor immune responses. Cancer Res; 70(1); 129–38.
Data from The Insulin-like Growth Factor-1 Receptor–Targeting Antibody, CP-751,871, Suppresses Tumor-Derived VEGF and Synergizes with Rapamycin in Models of Childhood Sarcoma
Authors: Kurmasheva Raushan T. , Dudkin Lorina , Billups Catherine , Debelenko Larisa V. , Morton Christopher L. , Houghton Peter J.
Published: March 2023

Abstract
Signaling through the type 1 insulin-like growth factor receptor (IGF-1R) occurs in many human cancers, including childhood sarcomas. As a consequence, targeting the IGF-1R has become a focus for cancer drug development. We examined the antitumor activity of CP-751,871, a human antibody that blocks IGF-1R ligand binding, alone and in combination with rapamycin against sarcoma cell lines in vitro and xenograft models in vivo. In Ewing sarcoma (EWS) cell lines, CP751,871 inhibited growth poorly (<50%), but prevented rapamycin-induced hyperphosphorylation of AKT(Ser473) and induced greater than additive apoptosis. Rapamycin treatment also increased secretion of IGF-1 resulting in phosphorylation of IGF-1R (Tyr1131) that was blocked by CP751,871. In vivo CP-751,871, rapamycin, or the combination were evaluated against EWS, osteosarcoma, and rhabdomyosarcoma xenografts. CP751871 induced significant growth inhibition [EFS(T/C) >2] in four models. Rapamycin induced significant growth inhibition [EFS(T/C) >2] in nine models. Although neither agent given alone caused tumor regressions, in combination, these agents had greater than additive activity against 5 of 13 xenografts and induced complete remissions in one model each of rhabdomyosarcoma and EWS, and in three of four osteosarcoma models. CP751,871 caused complete IGF-1R down-regulation, suppression of AKT phosphorylation, and dramatically suppressed tumor-derived vascular endothelial growth factor (VEGF) in some sarcoma xenografts. Rapamycin treatment did not markedly suppress VEGF in tumors and synergized only in tumor lines where VEGF was dramatically inhibited by CP751,871. These data suggest a model in which blockade of IGF-1R suppresses tumor-derived VEGF to a level where rapamycin can effectively suppress the response in vascular endothelial cells. [Cancer Res 2009;69(19):7662–71]
Data from DC-HIL/Glycoprotein Nmb Promotes Growth of Melanoma in Mice by Inhibiting the Activation of Tumor-Reactive T Cells
Authors: Tomihari Mizuki , Chung Jin-Sung , Akiyoshi Hideo , Cruz Ponciano D. , Ariizumi Kiyoshi
Published: March 2023

Abstract
DC-HIL/glycoprotein nmb (Gpnmb) expressed on antigen-presenting cells attenuates T-cell activation by binding to syndecan-4 (SD-4) on activated T cells. Because DC-HIL/Gpnmb is expressed abundantly by mouse and human melanoma lines, we posited that melanoma-associated DC-HIL/Gpnmb exerts similar inhibitory function on melanoma-reactive T cells. We generated small interfering RNA–transfected B16F10 melanoma cells to completely knock down DC-HIL/Gpnmb expression, with no alteration in cell morphology, melanin synthesis, or MHC class I expression. This knockdown had no effect on B16F10 proliferation in vitro or entry into the cell cycle following growth stimulation, but it markedly reduced the growth of these cells in vivo following their s.c. injection into syngeneic immunocompetent (but not immunodeficient) mice. This reduction in tumor growth was due most likely to an augmented capacity of DC-HIL–knocked down B16F10 cells (compared with controls) to activate melanoma-reactive T cells as documented in vitro and in mice. Whereas DC-HIL knockdown had no effect on susceptibility of melanoma to killing by cytotoxic T cells, blocking SD-4 function enhanced the reactivity of CD8+ T cells to melanoma-associated antigens on parental B16F10 cells. Using an assay examining the spread to the lung following i.v. injection, DC-HIL–knocked down cells produced lung foci at similar numbers compared with that produced by control cells, but the size of the former foci was significantly smaller than the latter. We conclude that DC-HIL/Gpnmb confers upon melanoma the ability to downregulate the activation of melanoma-reactive T cells, thereby allowing melanoma to evade immunologic recognition and destruction. As such, the DC-HIL/SD-4 pathway is a potentially useful target for antimelanoma immunotherapy. Cancer Res; 70(14); 5778–87. ©2010 AACR.
Data from Prolyl Hydroxylases 2 and 3 Act in Gliomas as Protective Negative Feedback Regulators of Hypoxia-Inducible Factors
Authors: Henze Anne-Theres , Riedel Johanna , Diem Tanja , Wenner Julia , Flamme Ingo , Pouyseggur Jacques , Plate Karl H. , Acker Till
Published: March 2023

Abstract
Adaptive responses to hypoxia in tumors are transcriptionally regulated by the hypoxia inducible factors (HIF-1α/HIF-2α), which are tightly controlled by the HIF-prolyl hydroxylases (PHD). Hypoxia induces expression of the PHD2 and PHD3 proteins in tumors but the pathobiological significance of these events is uncertain. Here, we show that PHD2 and PHD3 induction acts within a negative feedback loop to limit the hypoxic HIF response. In glioblastomas, PHD2 and PHD3 are hypoxia-inducible in vitro and expressed in hypoxic areas of tumors in vivo. Comparison with other PHDs revealed distinct cytoplasmatic and nuclear localization patterns of PHD2 and PHD3. Gain and loss of function experiments defined PHD2 and PHD3 as HIF target genes that remained operative even at low oxygen concentrations. We found that increased PHD levels could compensate for reduced oxygen availability to regulate the HIF response. This negative feedback loop protected tumor cells against hypoxia-induced cell death, functionally implicating this pathway in the control of the tumor-suppressive components of the HIF system in glioblastoma. Moreover, PHD inhibition facilitated cell death induction by staurosporine or tumor necrosis factor–related apoptosis-inducing ligand, hinting at a more general protective role of PHD in the regulation of cell viability. In summary, our findings recognize the PHD/HIF regulatory axis as a novel therapeutic target to disable a tumor's ability to adjust to hypoxic conditions and control cell survival, helping to potentially overcome therapeutic cell death resistance in glioblastomas. Cancer Res; 70(1); 357–66
Data from 6-Thioguanine Selectively Kills BRCA2-Defective Tumors and Overcomes PARP Inhibitor Resistance
Authors: Issaeva Natalia , Thomas Huw D. , Djurenovic Tatjana , Jaspers Janneke E. , Stoimenov Ivaylo , Kyle Suzanne , Pedley Nicholas , Gottipati Ponnari , Zur Rafal , Sleeth Kate , Chatzakos Vicky , Mulligan Evan A. , Lundin Cecilia , Gubanova Evgenia , Kersbergen Ariena , Harris Adrian L. , Sharma Ricky A. , Rottenberg Sven , Curtin Nicola J. , Helleday Thomas
Published: March 2023

Abstract
Familial breast and ovarian cancers are often defective in homologous recombination (HR) due to mutations in the BRCA1 or BRCA2 genes. Cisplatin chemotherapy or poly(ADP-ribose) polymerase (PARP) inhibitors were tested for these tumors in clinical trials. In a screen for novel drugs that selectively kill BRCA2-defective cells, we identified 6-thioguanine (6TG), which induces DNA double-strand breaks (DSB) that are repaired by HR. Furthermore, we show that 6TG is as efficient as a PARP inhibitor in selectively killing BRCA2-defective tumors in a xenograft model. Spontaneous BRCA1-defective mammary tumors gain resistance to PARP inhibitors through increased P-glycoprotein expression. Here, we show that 6TG efficiently kills such BRCA1-defective PARP inhibitor–resistant tumors. We also show that 6TG could kill cells and tumors that have gained resistance to PARP inhibitors or cisplatin through genetic reversion of the BRCA2 gene. Although HR is reactivated in PARP inhibitor–resistant BRCA2-defective cells, it is not fully restored for the repair of 6TG-induced lesions. This is likely to be due to several recombinogenic lesions being formed after 6TG. We show that BRCA2 is also required for survival from mismatch repair–independent lesions formed by 6TG, which do not include DSBs. This suggests that HR is involved in the repair of 6TG-induced DSBs as well as mismatch repair–independent 6TG-induced DNA lesion. Altogether, our data show that 6TG efficiently kills BRCA2-defective tumors and suggest that 6TG may be effective in the treatment of advanced tumors that have developed resistance to PARP inhibitors or platinum-based chemotherapy. Cancer Res; 70(15); 6268–76. ©2010 AACR.
Data from Low Ascorbate Levels Are Associated with Increased Hypoxia-Inducible Factor-1 Activity and an Aggressive Tumor Phenotype in Endometrial Cancer
Authors: Kuiper Caroline , Molenaar Ilona G.M. , Dachs Gabi U. , Currie Margaret J. , Sykes Peter H. , Vissers Margreet C.M.
Published: March 2023

Abstract
Activation of the transcription factor hypoxia-inducible factor (HIF)-1 allows solid tumors to thrive under conditions of metabolic stress. Because HIF-1 is switched off by hydroxylation reactions that require ascorbate, inadequate intracellular ascorbate levels could contribute to HIF-1 overactivation. In this study, we investigated whether the ascorbate content of human endometrial tumors [known to be driven by HIF-1 and vascular endothelial growth factor (VEGF)] influenced HIF-1 activity and tumor pathology. We measured protein levels of HIF-1α and three downstream gene products [glucose transporter 1 (GLUT-1), Bcl-2/adenovirus E1B 19 kDa interacting protein 3 (BNIP3), and VEGF], as well as the ascorbate content of tumor and patient-matched normal endometrial tissue samples. HIF-1α and its downstream gene products were upregulated in tumor tissue, with the highest levels being present in high-grade tumors. High-grade tumors also had reduced capacity to accumulate ascorbate compared with normal tissue; however, all grades contained tumors with low ascorbate content. Tumors with the highest HIF-1α protein content were ascorbate deficient. Low ascorbate levels were also associated with elevated VEGF, GLUT-1, and BNIP3 protein levels and with increased tumor size, and there was a significant association between low tissue ascorbate levels and increased activation of the HIF-1 pathway (P = 0.007). In contrast, tumors with high ascorbate levels had lesser levels of HIF-1 activation. This study shows for the first time a likely in vivo relationship between ascorbate and HIF-1, with low tumor tissue ascorbate levels being associated with high HIF-1 activation and tumor growth. Cancer Res; 70(14); 5749–58. ©2010 AACR.
Data from Mitochondrial Chaperone Trap1 and the Calcium Binding Protein Sorcin Interact and Protect Cells against Apoptosis Induced by Antiblastic Agents
Authors: Landriscina Matteo , Laudiero Gabriella , Maddalena Francesca , Amoroso Maria Rosaria , Piscazzi Annamaria , Cozzolino Flora , Monti Maria , Garbi Corrado , Fersini Alberto , Pucci Piero , Esposito Franca
Published: March 2023

Abstract
TRAP1, a mitochondrial chaperone (Hsp75) with antioxidant and antiapoptotic functions, is involved in multidrug resistance in human colorectal carcinoma cells. Through a proteomic analysis of TRAP1 coimmunoprecipitation complexes, the Ca2+-binding protein Sorcin was identified as a new TRAP1 interactor. This result prompted us to investigate the presence and role of Sorcin in mitochondria from human colon carcinoma cells. Using fluorescence microscopy and Western blot analysis of purified mitochondria and submitochondrial fractions, we showed the mitochondrial localization of an isoform of Sorcin with an electrophoretic motility lower than 20 kDa that specifically interacts with TRAP1. Furthermore, the effects of overexpressing or downregulating Sorcin and/or TRAP1 allowed us to demonstrate a reciprocal regulation between these two proteins and to show that their interaction is required for Sorcin mitochondrial localization and TRAP1 stability. Indeed, the depletion of TRAP1 by short hairpin RNA in colorectal carcinoma cells lowered Sorcin levels in mitochondria, whereas the depletion of Sorcin by small interfering RNA increased TRAP1 degradation. We also report several lines of evidence suggesting that intramitochondrial Sorcin plays a role in TRAP1 cytoprotection. Finally, preliminary evidence that TRAP1 and Sorcin are both implicated in multidrug resistance and are coupregulated in human colorectal carcinomas is provided. These novel findings highlight a new role for Sorcin, suggesting that some of its previously reported cytoprotective functions may be explained by involvement in mitochondrial metabolism through the TRAP1 pathway. Cancer Res; 70(16); 6577–86. ©2010 AACR.
Data from Targeted Activation of RNA Helicase Retinoic Acid–Inducible Gene-I Induces Proimmunogenic Apoptosis of Human Ovarian Cancer Cells
Authors: Kübler Kirsten , Gehrke Nadine , Riemann Soheila , Böhnert Volker , Zillinger Thomas , Hartmann Evelyn , Pölcher Martin , Rudlowski Christian , Kuhn Walther , Hartmann Gunther , Barchet Winfried
Published: March 2023

Abstract
Most malignant cells are poorly immunogenic and fail to elicit an effective antitumor immune response. In contrast, viral infections of cells are promptly detected and eliminated by the immune system. Viral recognition critically hinges on cytosolic nucleic acid receptors that include the proinflammatory RNA helicase retinoic acid–inducible gene-I (RIG-I). Here, we show that targeted delivery of RIG-I agonists induced ovarian cancer cells to upregulate HLA class I and to secrete the proinflammatory cytokines CXCL10, CCL5, interleukin-6, tumor necrosis factor-α, and IFN-β. Ovarian cancer cells stimulated via RIG-I became apoptotic and were readily phagocytosed by monocytes and monocyte-derived dendritic cells, which in turn upregulated HLA class I/II and costimulatory molecules and released CXCL10 and IFN-α. Our findings offer proof of principle that mimicking viral infection in ovarian cancer cells triggers an immunogenic form of tumor cell apoptosis that may enhance immunotherapy of ovarian cancer. Cancer Res; 70(13); 5293–304. ©2010 AACR.
Data from Hypoxia Modulates EWS-FLI1 Transcriptional Signature and Enhances the Malignant Properties of Ewing's Sarcoma Cells In vitro
Authors: Aryee Dave N.T. , Niedan Stephan , Kauer Maximilian , Schwentner Raphaela , Bennani-Baiti Idriss M. , Ban Jozef , Muehlbacher Karin , Kreppel Michael , Walker Robert L. , Meltzer Paul , Poremba Christopher , Kofler Reinhard , Kovar Heinrich
Published: March 2023

Abstract
Hypoxia is an important condition in the tumor cell microenvironment and approximately 1% to 1.5% of the genome is transcriptionally responsive to hypoxia with hypoxia-inducible factor-1 (HIF-1) as a major mediator of transcriptional activation. Tumor hypoxia is associated with a more aggressive phenotype of many cancers in adults, but data on pediatric tumors are scarce. Because, by immunohistochemistry, HIF-1α expression was readily detectable in 18 of 28 primary Ewing's sarcoma family tumors (ESFT), a group of highly malignant bone-associated tumors in children and young adults, we studied the effect of hypoxia on ESFT cell lines in vitro. Intriguingly, we found that EWS-FLI1 protein expression, which characterizes ESFT, is upregulated by hypoxia in a HIF-1α–dependent manner. Hypoxia modulated the EWS-FLI1 transcriptional signature relative to normoxic conditions. Both synergistic as well as antagonistic transcriptional effects of EWS-FLI1 and of hypoxia were observed. Consistent with alterations in the expression of metastasis-related genes, hypoxia stimulated the invasiveness and soft agar colony formation of ESFT cells in vitro. Our data represent the first transcriptome analysis of hypoxic ESFT cells and identify hypoxia as an important microenvironmental factor modulating EWS-FLI1 expression and target gene activity with far-reaching consequences for the malignant properties of ESFT. Cancer Res; 70(10); 4015–23. ©2010 AACR.
Data from Direct Activation of Emmprin and Associated Pathogenesis by an Oncogenic Herpesvirus
Authors: Qin Zhiqiang , Dai Lu , Slomiany Mark G. , Toole Bryan P. , Parsons Chris
Published: March 2023

Abstract
Emmprin (extracellular matrix metalloproteinase inducer) is a multifunctional glycoprotein expressed by cancer cells and stromal cells in the tumor microenvironment. Through both direct effects within tumor cells and promotion of tumor-stroma interactions, emmprin induces tumor cell invasiveness and regional angiogenesis. The Kaposi's sarcoma–associated herpesvirus (KSHV) is a common etiology for cancers arising in the setting of immune suppression, including Kaposi's sarcoma and primary effusion lymphoma. However, whether emmprin expression and function are regulated by KSHV or other oncogenic viruses in the tumor microenvironment to promote viral cancer pathogenesis remains unknown. Fibroblasts and endothelial cells support latent KSHV infection and represent cellular components of Kaposi's sarcoma lesions. Therefore, we used primary human fibroblasts and endothelial cells to determine whether KSHV itself regulates emmprin expression, and whether KSHV-emmprin interactions mediate cell invasiveness. We found that KSHV promotes fibroblast and endothelial cell invasiveness following de novo infection through the upregulation of emmprin, and that this effect is mediated by the KSHV-encoded latency-associated nuclear antigen. We also found that emmprin promotes invasiveness, as well as colony formation, by primary effusion lymphoma cells derived from human tumors. Collectively, these data implicate KSHV activation of emmprin as an important mechanism for cancer progression and support the potential utility of targeting emmprin as a novel therapeutic approach for KSHV-associated tumors. Cancer Res; 70(10); 3884–9. ©2010 AACR.
Data from E2F3a Is Critically Involved in Epidermal Growth Factor Receptor–Directed Proliferation in Ovarian Cancer
Authors: Reimer Daniel , Hubalek Michael , Riedle Svenja , Skvortsov Sergej , Erdel Martin , Concin Nicole , Fiegl Heidi , Müller-Holzner Elisabeth , Marth Christian , Illmensee Karl , Altevogt Peter , Zeimet Alain G.
Published: March 2023

Abstract
We describe for the first time a new integral molecular pathway, linking transcription factor E2F3a to epidermal growth factor receptor (EGFR) activation in ovarian cancer cells. Investigations on the role of E2F family members in EGFR-mediated mitogenic signaling revealed that E2F3a was selectively upregulated following EGFR activation, whereas all other E2F family members remained unaffected. In contrast, EGF treatment of healthy ovarian surface epithelial and mesothelial cells yielded a selective upregulation of proliferation-promoting E2F1 and E2F2 without influencing E2F3a expression. In ovarian cancer cell lines, the extent of EGF-induced proliferative stimulus was closely related to the magnitude of E2F3a increase, and proliferation inhibition by E2F3a knockdown was not overcome by EGF exposure. Furthermore, the EGFR-E2F3a axis was found to be signal transducer and activator of transcription 1/3 dependent and the ratio of IFN-regulatory factor (IRF)-1 to IRF-2 was shown to be determinative for E2F3a control. In a pilot study on 32 primary ovarian cancer specimens, a highly significant correlation between activated EGFR and E2F3a expression was disclosed. This new integral pathway in the EGFR-driven mitogenic cell response, which through its key player E2F3a was found to be essential in triggering proliferation in ovarian cancer cells, provides new insights into EGFR signaling and could represent the basis for appealing new therapeutic approaches in ovarian cancer. Cancer Res; 70(11); 4613–23. ©2010 AACR.
Data from PML-RARα and Dnmt3a1 Cooperate in vivo to Promote Acute Promyelocytic Leukemia
Authors: Subramanyam Deepa , Belair Cassandra D. , Barry-Holson Keegan Q. , Lin Haijiang , Kogan Scott C. , Passegué Emmanuelle , Blelloch Robert
Published: March 2023

Abstract
The PML-RARα oncogene is the central effector of acute promyelocytic leukemia (APL). PML-RARα physically interacts with epigenetic-modifying enzymes including DNA methyltransferases (Dnmt) to suppress critical downstream targets. Here, we show that increased expression of Dnmt3a1 cooperates with PML-RARα in vivo to promote early lethality secondary to myeloid expansion and dysfunction in primary mice. Bone marrow cells from these mice cause leukemogenesis with a shortened latency and a higher penetrance on transplantation into irradiated recipients. Furthermore, leukemic cells overexpressing PML-RARα and Dnmt3a1 display increased methylation at a target promoter compared with PML-RARα or Dnmt3a1 controls. Our findings show a cooperation between the PML-RARα oncogene and the Dnmt3a1 enzyme in vivo and that Dnmt levels can be rate limiting in APL progression. Cancer Res; 70(21); 8792–801. ©2010 AACR.
Data from Arrest Defective 1 Autoacetylation Is a Critical Step in Its Ability to Stimulate Cancer Cell Proliferation
Authors: Seo Ji Hae , Cha Jong-Ho , Park Ji-Hyeon , Jeong Chul-Ho , Park Zee-Yong , Lee Hye-Suk , Oh Seung Hyun , Kang Ju-Hee , Suh Se Won , Kim Kyoung Hoon , Ha Jun Yong , Han Sang Hee , Kim Se-Hee , Lee Ji-Won , Park Jeong Ae , Jeong Joo-Won , Lee Kong-Joo , Oh Goo Taeg , Lee Mi-Ni , Kwon Sung Won , Lee Seung-Ki , Chun Kwang-Hoon , Lee Su-Jae , Kim Kyu-Won
Published: March 2023

Abstract
The N-acetyltransferase arrest defective 1 (ARD1) is an important regulator of cell growth and differentiation that has emerged recently as a critical molecule in cancer progression. However, the regulation of the enzymatic and biological activities of human ARD1 (hARD1) in cancer is presently poorly understood. Here, we report that hARD1 undergoes autoacetylation and that this modification is essential for its functional activation. Using liquid chromatography-tandem mass spectrometry and site-directed mutational analyses, we identified K136 residue as an autoacetylation target site. K136R mutation abolished the ability of hARD1 to promote cancer cell growth in vitro and tumor xenograft growth in vivo. Mechanistic investigations revealed that hARD1 autoacetylation stimulated cyclin D1 expression through activation of the transcription factors β-catenin and activator protein-1. Our results show that hARD1 autoacetylation is critical for its activation and its ability to stimulate cancer cell proliferation and tumorigenesis. Cancer Res; 70(11); 4422–32. ©2010 AACR.
Data from FOXO3 Encodes a Carcinogen-Activated Transcription Factor Frequently Deleted in Early-Stage Lung Adenocarcinoma
Authors: Mikse Oliver R. , Blake Daniel C. , Jones Nathan R. , Sun Yuan-Wan , Amin Shantu , Gallagher Carla J. , Lazarus Philip , Weisz Judith , Herzog Christopher R.
Published: March 2023

Abstract
The FOXO family of transcription factors elicits cell cycle arrest, apoptosis, and resistance to various physiologic and pathologic stresses relevant to sporadic cancer, such as DNA damage and oxidative stress. Although implicated as tumor suppressors, FOXO genetic inactivation has not been observed in human cancer. In an investigation of the two major types of non–small cell lung cancer, here, we identify the FOXO3 gene as a novel target of deletion in human lung adenocarcinoma (LAC). Biallelic or homozygous deletion (HD) of FOXO3 was detected in 8 of 33 (24.2%) mostly early-stage LAC of smokers. Another 60.6% of these tumors had losses of FOXO3 not reaching the level of HD (hereafter referred to as sub-HD). In contrast, no HD of FOXO3 was observed in 19 lung squamous cell carcinoma. Consistent with the deletion of FOXO3 were corresponding decreases in its mRNA and protein levels in LAC. The potential role of FOXO3 loss in LAC was also investigated. The carcinogen (+)-anti-7,8-dihydroxy-9,10-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE) is strongly implicated as a cause of human lung cancer. Here, we show that FOXO3a is functionally activated and augments the level of caspase-dependent apoptosis in cells exposed to this DNA-damaging carcinogen. These results implicate FOXO3 as a suppressor of LAC carcinogenesis, a role frequently lost through gene deletion. Cancer Res; 70(15); 6205–15. ©2010 AACR.
Data from Glioblastoma Cells Require Glutamate Dehydrogenase to Survive Impairments of Glucose Metabolism or Akt Signaling
Authors: Yang Chendong , Sudderth Jessica , Dang Tuyen , Bachoo Robert G. , McDonald Jeffrey G. , DeBerardinis Ralph J.
Published: March 2023

Abstract
Oncogenes influence nutrient metabolism and nutrient dependence. The oncogene c-Myc stimulates glutamine metabolism and renders cells dependent on glutamine to sustain viability (“glutamine addiction”), suggesting that treatments targeting glutamine metabolism might selectively kill c-Myc–transformed tumor cells. However, many current or proposed cancer therapies interfere with the metabolism of glucose, not glutamine. Here, we studied how c-Myc–transformed cells maintained viability when glucose metabolism was impaired. In SF188 glioblastoma cells, glucose deprivation did not affect net glutamine utilization but elicited a switch in the pathways used to deliver glutamine carbon to the tricarboxylic acid cycle, with a large increase in the activity of glutamate dehydrogenase (GDH). The effect on GDH resulted from the loss of glycolysis because it could be mimicked with the glycolytic inhibitor 2-deoxyglucose and reversed with a pyruvate analogue. Furthermore, inhibition of Akt signaling, which facilitates glycolysis, increased GDH activity whereas overexpression of Akt suppressed it, suggesting that Akt indirectly regulates GDH through its effects on glucose metabolism. Suppression of GDH activity with RNA interference or an inhibitor showed that the enzyme is dispensable in cells able to metabolize glucose but is required for cells to survive impairments of glycolysis brought about by glucose deprivation, 2-deoxyglucose, or Akt inhibition. Thus, inhibition of GDH converted these glutamine-addicted cells to glucose-addicted cells. The findings emphasize the integration of glucose metabolism, glutamine metabolism, and oncogenic signaling in glioblastoma cells and suggest that exploiting compensatory pathways of glutamine metabolism can improve the efficacy of cancer treatments that impair glucose utilization. [Cancer Res 2009;69(20):7986–93]
Data from Chemotherapy-Induced Genotoxic Stress Promotes Sensitivity to Natural Killer Cell Cytotoxicity by Enabling Missing-Self Recognition
Authors: Fine Jason H. , Chen Peter , Mesci Aruz , Allan David S.J. , Gasser Stephan , Raulet David H. , Carlyle James R.
Published: March 2023

Abstract
Natural killer (NK) cells can recognize and kill tumor cells lacking “self” markers, such as class I MHC, but the basis for this recognition is not completely understood. NKR-P1 receptors are members of the C-type lectin-related NK receptor superfamily that are conserved from rodents to humans. Identification of Clr ligands for the NKR-P1 receptors has facilitated functional analysis of MHC-independent target cell recognition by NK cells. One receptor-ligand pair, NKR-P1B:Clr-b, can mediate “missing-self” recognition of tumor and infected cells, but the role of this axis in sensing stressed cells remains unknown. Here, we show that Clr-b is rapidly downregulated in cells undergoing genotoxic and cellular stress at the level of both RNA and surface protein. Stress-mediated loss of Clr-b on leukemia cells enhanced cytotoxicity mediated by NKR-P1B+ NK cells. Notably, Clr-b downregulation was coordinated functionally with stress-mediated upregulation of NKG2D ligands (but not class I MHC). Our findings highlight a unique role for the MHC-independent NKR-P1B:Clr-b missing-self axis in recognition of stressed cells, and provide evidence of two independent levels of Clr-b regulation in stressed cells. Cancer Res; 70(18); 7102–13. ©2010 AACR.
Data from Inhibition of Rho-Associated Kinase Signaling Prevents Breast Cancer Metastasis to Human Bone
Authors: Liu Sijin , Goldstein Robert H. , Scepansky Ellen M. , Rosenblatt Michael
Published: March 2023

Abstract
Rho-associated kinase (ROCK) signaling plays a fundamental role in regulating cell morphology, adhesion, and motility. Aberrant expression of ROCK is related to tumor metastases and poor clinical outcome. Here, we show that ROCK expression is increased in metastatic human mammary tumors and breast cancer cell lines compared with nonmetastatic tumors and cell lines. Overexpression of ROCK confers a metastatic phenotype on the nonmetastatic MCF-7 cell line. Inhibition of ROCK activity, by either a specific ROCK inhibitor (Y27632) or ROCK-targeted small interfering RNAs, reduces cell migration and proliferation in vitro and metastasis to bone in vivo using a novel “human breast cancer metastasis to human bone” mouse model. Expression of the c-Myc–regulated miR-17-92 cluster is shown to be elevated in metastatic breast cancer cells compared with nonmetastatic cells and diminished by Y27632 treatment. Furthermore, blockade of miR-17 is shown to decrease breast cancer cell invasion/migration in vitro and metastasis in vivo. Together, these findings suggest that augmented ROCK signaling contributes to breast cancer metastasis. The effects of ROCK on tumor cell invasion/motility and growth may derive from regulating cytoskeletal actin-myosin contraction and modulating the c-Myc pathway, including c-Myc–dependent microRNAs. Inhibition of ROCK or the pathway it stimulates, therefore, may represent a novel approach for treatment of breast cancer metastases. [Cancer Res 2009;69(22):8742–51]
Data from Carcinomas Contain a Matrix Metalloproteinase–Resistant Isoform of Type I Collagen Exerting Selective Support to Invasion
Authors: Makareeva Elena , Han Sejin , Vera Juan Carlos , Sackett Dan L. , Holmbeck Kenn , Phillips Charlotte L. , Visse Robert , Nagase Hideaki , Leikin Sergey
Published: March 2023

Abstract
Collagen fibers affect metastasis in two opposing ways, by supporting invasive cells but also by generating a barrier to invasion. We hypothesized that these functions might be performed by different isoforms of type I collagen. Carcinomas are reported to contain α1(I)3 homotrimers, a type I collagen isoform normally not present in healthy tissues, but the role of the homotrimers in cancer pathophysiology is unclear. In this study, we found that these homotrimers were resistant to all collagenolytic matrix metalloproteinases (MMP). MMPs are massively produced and used by cancer cells and cancer-associated fibroblasts for degrading stromal collagen at the leading edge of tumor invasion. The MMP-resistant homotrimers were produced by all invasive cancer cell lines tested, both in culture and in tumor xenografts, but they were not produced by cancer-associated fibroblasts, thereby comprising a specialized fraction of tumor collagen. We observed the homotrimer fibers to be resistant to pericellular degradation, even upon stimulation of the cells with proinflammatory cytokines. Furthermore, we confirmed an enhanced proliferation and migration of invasive cancer cells on the surface of homotrimeric versus normal (heterotrimeric) type I collagen fibers. In summary, our findings suggest that invasive cancer cells may use homotrimers for building MMP-resistant invasion paths, supporting local proliferation and directed migration of the cells whereas surrounding normal stromal collagens are cleaved. Because the homotrimers are universally secreted by cancer cells and deposited as insoluble, MMP-resistant fibers, they offer an appealing target for cancer diagnostics and therapy. Cancer Res; 70(11); 4366–74. ©2010 AACR.
Data from A Novel Paradigm to Trigger Apoptosis in Chronic Lymphocytic Leukemia
Authors: Loeder Sandra , Zenz Thorsten , Schnaiter Andrea , Mertens Daniel , Winkler Dirk , Döhner Hartmut , Debatin Klaus-Michael , Stilgenbauer Stephan , Fulda Simone
Published: March 2023

Abstract
Evasion of apoptosis is a hallmark of chronic lymphocytic leukemia (CLL), calling for new strategies to bypass resistance. Here, we provide first evidence that small-molecule X-linked inhibitor of apoptosis (XIAP) inhibitors in combination with the death receptor ligand tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) present a novel approach to trigger apoptosis in CLL, including subgroups with resistant disease or unfavorable prognosis. XIAP, cellular IAP (cIAP) 1, and cIAP2 are expressed at high levels in primary CLL samples. Proof-of-concept studies in CLL cell lines show that subtoxic concentrations of XIAP inhibitors significantly enhance TRAIL-induced apoptosis and also sensitize for CD95-mediated apoptosis. Importantly also in primary CLL samples, XIAP inhibitor acts in concert with TRAIL to trigger apoptosis in 18 of 27 (67%) cases. This XIAP inhibitor–induced and TRAIL-induced apoptosis involves caspase-3 activation and is blocked by the caspase inhibitor zVAD.fmk. The cooperative interaction of XIAP inhibitor and TRAIL is even evident in distinct subgroups of patients with poor prognostic features (i.e., with 17p deletion, TP53 mutation, chemotherapy-refractory disease, or unmutated VH genes). Interestingly, cases with unmutated VH genes were significantly more sensitive to XIAP inhibitor–induced and TRAIL-induced apoptosis compared with VH gene–mutated samples, pointing to a role of B-cell receptor signaling in apoptosis regulation. By showing that XIAP inhibitors in combination with TRAIL present a new strategy to trigger apoptosis even in resistant forms and poor prognostic subgroups of CLL, our findings have important implications for the development of apoptosis-based therapies in CLL. [Cancer Res 2009;69(23):8977–86]
Data from Coactivated Platelet-Derived Growth Factor Receptor α and Epidermal Growth Factor Receptor Are Potential Therapeutic Targets in Intimal Sarcoma
Authors: Dewaele Barbara , Floris Giuseppe , Finalet-Ferreiro Julio , Fletcher Christopher D. , Coindre Jean-Michel , Guillou Louis , Hogendoorn Pancras C.W. , Wozniak Agnieszka , Vanspauwen Vanessa , Schöffski Patrick , Marynen Peter , Vandenberghe Peter , Sciot Raf , Debiec-Rychter Maria
Published: March 2023

Abstract
Intimal sarcoma (IS) is a rare, malignant, and aggressive tumor that shows a relentless course with a concomitant low survival rate and for which no effective treatment is available. In this study, 21 cases of large arterial blood vessel IS were analyzed by immunohistochemistry and fluorescence in situ hybridization and selectively by karyotyping, array comparative genomic hybridization, sequencing, phospho-kinase antibody arrays, and Western immunoblotting in search for novel diagnostic markers and potential molecular therapeutic targets. Ex vivo immunoassays were applied to test the sensitivity of IS primary tumor cells to the receptor tyrosine kinase (RTK) inhibitors imatinib and dasatinib. We showed that amplification of platelet-derived growth factor receptor α (PDGFRA) is a common finding in IS, which should be considered as a molecular hallmark of this entity. This amplification is consistently associated with PDGFRA activation. Furthermore, the tumors reveal persistent activation of the epidermal growth factor receptor (EGFR), concurrent to PDGFRA activation. Activated PDGFRA and EGFR frequently coexist with amplification and overexpression of the MDM2 oncogene. Ex vivo immunoassays on primary IS cells from one case showed the potency of dasatinib to inhibit PDGFRA and downstream signaling pathways. Our findings provide a rationale for investigating therapies that target PDGFRA, EGFR, or MDM2 in IS. Given the clonal heterogeneity of this tumor type and the potential cross-talk between the PDGFRA and EGFR signaling pathways, targeting multiple RTKs and aberrant downstream effectors might be required to improve the therapeutic outcome for patients with this disease. Cancer Res; 70(18); 7304–14. ©2010 AACR.
Data from Phosphomimetic Mutants of Pigment Epithelium-Derived Factor with Enhanced Antiangiogenic Activity as Potent Anticancer Agents
Authors: Konson Alexander , Pradeep Sunila , Seger Rony
Published: March 2023

Abstract
Pigment epithelium-derived factor (PEDF) is an endogenous inhibitor of angiogenesis and a promising anticancer agent capable of suppressing solid tumor growth in animal cancer models. We have previously shown that PEDF can be phosphorylated and that distinct phosphorylation states of this factor differentially regulate its physiologic function. Here, we report that phosphomimetic mutants of PEDF, which possess significantly increased antiangiogenic activity, are much more efficient than wild-type (WT) PEDF in inhibiting growth and neovascularization in MDA-MB-231 (breast cancer), HCT116 (colon cancer), and U87-MG (glioblastoma) xenograft models. Importantly, the antitumor activity of the phosphomimetic mutants is comparable with that of the established antiangiogenic agent bevacizumab. However, unlike bevacizumab, these compounds act in a vascular endothelial growth factor (VEGF)–independent manner, as they do not affect the levels of VEGF-A mRNA and VEGF receptor 2 phosphorylation. Further immunohistochemical analysis revealed that PEDF mutants affect mainly tumor-residing endothelial cells and prevent the formation of intratumoral vascular network by facilitating endothelial cell apoptosis. It was also found that PEDF mutants reduce survival of endothelial cells in culture much better than WT-PEDF, an effect that is apparent even in the presence of VEGF or basic fibroblast growth factor, and promote much stronger endothelial cell apoptosis. On the other hand, PEDF and its mutants did not affect survival of cultured cancer cells, indicating that the antiangiogenic activity of these agents is the foremost element of the observed antitumor effect. These findings have specific implications on improving the properties of WT-PEDF, which is currently in preclinical development, and encourage the development of PEDF mutants as specific, neovascularization-targeting anticancer agents. Cancer Res; 70(15); 6247–57. ©2010 AACR.
Data from De novo Discovery of a γ-Secretase Inhibitor Response Signature Using a Novel In vivo Breast Tumor Model
Authors: Watters James W. , Cheng Chun , Majumder Pradip K. , Wang Ruojie , Yalavarthi Sireesha , Meeske Carol , Kong Lingxin , Sun Wenping , Lin Jie , Heyer Joerg , Ware Chris , Winter Christopher , Reilly John F. , Demuth Tim , Clark Steve , Chiu M. Isabel , Robinson Murray O. , Kohl Nancy , Kannan Karuppiah
Published: March 2023

Abstract
Notch pathway signaling plays a fundamental role in normal biological processes and is frequently deregulated in many cancers. Although several hypotheses regarding cancer subpopulations most likely to respond to therapies targeting the Notch pathway have been proposed, clinical utility of these predictive markers has not been shown. To understand the molecular basis of γ-secretase inhibitor (GSI) sensitivity in breast cancer, we undertook an unbiased, de novo responder identification study using a novel genetically engineered in vivo breast cancer model. We show that tumors arising from this model are heterogeneous on the levels of gene expression, histopathology, growth rate, expression of Notch pathway markers, and response to GSI treatment. In addition, GSI treatment of this model was associated with inhibition of Hes1 and proliferation markers, indicating that GSI treatment inhibits Notch signaling. We then identified a pretreatment gene expression signature comprising 768 genes that is significantly associated with in vivo GSI efficacy across 99 tumor lines. Pathway analysis showed that the GSI responder signature is enriched for Notch pathway components and inflammation/immune-related genes. These data show the power of this novel in vivo model system for the discovery of biomarkers predictive of response to targeted therapies, and provide a basis for the identification of human breast cancers most likely to be sensitive to GSI treatment. [Cancer Res 2009;69(23):8949–57]