bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from VEGF and c-Met Blockade Amplify Angiogenesis Inhibition in Pancreatic Islet Cancer
Authors: You Weon-Kyoo , Sennino Barbara , Williamson Casey W. , Falcón Beverly , Hashizume Hiroya , Yao Li-Chin , Aftab Dana T. , McDonald Donald M.
Published: March 2024

Abstract
Angiogenesis inhibitors that block VEGF receptor (VEGFR) signaling slow the growth of many types of tumors, but eventually the disease progresses. Multiple strategies are being explored to improve efficacy by concurrent inhibition of other functionally relevant receptor tyrosine kinases (RTK). XL880 (foretinib, GSK1363089) and XL184 (cabozantinib) are small-molecule inhibitors that potently block multiple RTKs, including VEGFR and the receptor of hepatocyte growth factor c-Met, which can drive tumor invasion and metastasis. This study compared the cellular effects of XL880 and XL184 with those of an RTK inhibitor (XL999) that blocks VEGFR but not c-Met. Treatment of RIP-Tag2 mice with XL999 resulted in 43% reduction in vascularity of spontaneous pancreatic islet tumors over 7 days, but treatment with XL880 or XL184 eliminated approximately 80% of the tumor vasculature, reduced pericytes and empty basement membrane sleeves, caused widespread intratumoral hypoxia and tumor cell apoptosis, and slowed regrowth of the tumor vasculature after drug withdrawal. Importantly, XL880 and XL184 also decreased invasiveness of primary tumors and reduced metastasis. Overall, these findings indicate that inhibition of c-Met and functionally related kinases amplifies the effects of VEGFR blockade and leads to rapid, robust, and progressive regression of tumor vasculature, increased intratumoral hypoxia and apoptosis, and reduced tumor invasiveness and metastasis. Cancer Res; 71(14); 4758–68. ©2011 AACR.
Data from Heat Shock Protein 60 Regulation of the Mitochondrial Permeability Transition Pore in Tumor Cells
Authors: Ghosh Jagadish C. , Siegelin Markus D. , Dohi Takehiko , Altieri Dario C.
Published: March 2024

Abstract
Mitochondrial apoptosis plays a critical role in tumor maintenance and dictates the response to therapy in vivo; however, the regulators of this process are still largely elusive. Here, we show that the molecular chaperone heat shock protein 60 (Hsp60) directly associates with cyclophilin D (CypD), a component of the mitochondrial permeability transition pore. This interaction occurs in a multichaperone complex comprising Hsp60, Hsp90, and tumor necrosis factor receptor-associated protein-1, selectively assembled in tumor but not in normal mitochondria. Genetic targeting of Hsp60 by siRNA triggers CypD–dependent mitochondrial permeability transition, caspase-dependent apoptosis, and suppression of intracranial glioblastoma growth in vivo. Therefore, Hsp60 is a novel regulator of mitochondrial permeability transition, contributing to a cytoprotective chaperone network that antagonizes CypD-dependent cell death in tumors. Cancer Res; 70(22); 8988–93. ©2010 AACR.
Data from Cytotoxic Activity of Immunotoxin SS1P Is Modulated by TACE-Dependent Mesothelin Shedding
Authors: Zhang Yujian , Chertov Oleg , Zhang Jingli , Hassan Raffit , Pastan Ira
Published: March 2024

Abstract
Mesothelin is a cell-surface tumor-associated antigen expressed in several human cancers. The limited expression of mesothelin on normal tissues and its high expression in many cancers make it an attractive candidate for targeted therapies using monoclonal antibodies, immunoconjugates, and immunotoxins. Mesothelin is actively shed from the cell surface and is present in the serum of patients with malignant mesothelioma, which could negatively affect the response to these therapies. We have found that mesothelin sheddase activity is mediated by a TNF-α converting enzyme (TACE), a member of the matrix metalloproteinase/a disintegrin and metalloprotease family. We showed that EGF and TIMP-3 act through TACE as endogenous regulators of mesothelin shedding. We also found that reducing shedding significantly improved the in vitro cytotoxicity of immunotoxin SS1P, which targets mesothelin and is currently in clinical trials for the treatment of patients with mesothelioma and lung cancer. Our findings provide a mechanistic understanding of mesothelin shedding and could help improve mesothelin-based targeted therapies. Cancer Res; 71(17); 5915–22. ©2011 AACR.
Data from Blocking EphB1 Receptor Forward Signaling in Spinal Cord Relieves Bone Cancer Pain and Rescues Analgesic Effect of Morphine Treatment in Rodents
Authors: Liu Su , Liu Wen-Tao , Liu Yue-Peng , Dong Hai-Long , Henkemeyer Mark , Xiong Li-Ze , Song Xue-Jun
Published: March 2024

Abstract
Treating bone cancer pain continues to be a clinical challenge and underlying mechanisms of bone cancer pain remain elusive. Here, we report that EphB1 receptor forward signaling in the spinal cord is critical to the development of bone cancer pain and morphine tolerance in treating bone cancer pain. Tibia bone cavity tumor cell implantation (TCI) produces bone cancer–related thermal hyperalgesia, mechanical allodynia, spontaneous and movement-evoked pain behaviors, and bone destruction. Production and persistence of these pain behaviors are well correlated with TCI-induced upregulation of EphB1 receptor and its ligand ephrinB2 in the dorsal horn and primary sensory neurons. Spinal administration of an EphB1 receptor blocking reagent EphB2-Fc prevents and reverses bone cancer pain behaviors and the associated induction of c-Fos and activation of astrocytes and microglial cells, NR1 and NR2B receptors, Src within the N-methyl-D-aspartate receptor complex, and the subsequent Ca2+-dependent signals. The exogenous ligand ephrinB2-Fc upregulates level of phosphorylation of NR1 and NR2B receptors depending on the activation of EphB1 receptor. Spinal administration of EphB2-Fc and ephrinB2-Fc induces downregulation of EphB1 and ephrinB2, respectively, accompanied with increased activity of matrix metalloproteinase (MMP)-2/9. Blocking MMP-2 or MMP-9 reverses EphB1-Fc treatment–induced downregulation of EphB1 receptor. In addition, spinal blocking or targeted mutation of EphB1 receptor reverses morphine tolerance in treating bone cancer pain in rats and defensive pain in mice. These findings show a critical mechanism underlying the pathogenesis of bone cancer pain and suggest a potential target for treating bone cancer pain and improving analgesic effect of morphine clinically. Cancer Res; 71(13); 4392–402. ©2011 AACR.
Data from Combinatorial Treatments That Overcome PDGFRβ-Driven Resistance of Melanoma Cells to V600EB-RAF Inhibition
Authors: Shi Hubing , Kong Xiangju , Ribas Antoni , Lo Roger S.
Published: March 2024

Abstract
V600EB-RAF mutation is found in 50% to 60% of melanomas, and the novel agents PLX4032/vemurafenib and GSK2118436 that inhibit the V600EB-RAF kinase achieve a remarkable clinical response rate. However, as might be expected, acquired clinical resistance to these agents arises in most melanoma patients. PLX4032/vemurafenib resistance that arises in vivo in tumor matched short-term cultures or in vitro in melanoma cell lines is not caused by acquisition of secondary mutations in V600EB-RAF but rather is caused by upregulating platelet-derived growth factor receptor β (PDGFRβ) or N-RAS which results in resistance or sensitivity to mitogen-activated protein (MAP)/extracellular signal-regulated (ERK; MEK) kinase inhibitors, respectively. In this study, we define a targeted combinatorial strategy to overcome PLX4032/vemurafenib resistance in melanoma cell lines or short-term culture where the resistance is driven by PDGFRβ upregulation, achieving synergistic growth inhibition and cytotoxicity. PDGFRβ-upregulated, PLX4032-resistant (PPRM) cell lines show dual phospho (p)-ERK and p-AKT upregulation, and their growth inhibitory responses to specific small molecule inhibitors correlated with p-ERK, p-AKT, and p-p70S6K levels. Coordinate inhibition of V600EB-RAF inhibition and the RTK–PI3K–AKT–mTORC axis led to functionally significant rebound signaling, illustrating a robust and dynamic network connectivity. Combined B-RAF, phosphoinositide 3-kinase (PI3K), and mTORC1/2 inhibition suppressed both immediate early and delayed compensatory signaling, resulting in a highly synergistic growth inhibitory response but less efficient cytotoxic response. In contrast, the combination of MEK1/2, PI3K, and mTORC1/2 inhibitors consistently triggered apoptosis in a highly efficient manner. Together, our findings offer a rational strategy to guide clinical testing in preidentified subsets of patients who relapse during treatment with V600EB-RAF inhibitors. Cancer Res; 71(15); 5067–74. ©2011 AACR.
Data from Increased Survival following Tumorigenesis in Ts65Dn Mice That Model Down Syndrome
Authors: Yang Annan , Reeves Roger H.
Published: March 2024

Abstract
Epidemiologic results tend to suggest that adults with Down syndrome have a reduced incidence of cancer, but some studies have reached the opposite conclusion. In this study, we offer direct biological evidence in support of the notion that Down syndrome reduces incidence of multiple types of cancer. Previous studies showed that introduction of the ApcMin mutation into the Ts65Dn mouse model of Down syndrome by interbreeding caused formation of intestinal adenomas at a significantly reduced incidence compared with control (euploid) animals that did not have trisomy. To a large degree, this reduction was determined to reflect an increased dosage of the Ets2 tumor repressor gene due to trisomy. Studies of tumor grafts using Ts65Dn suggested angiogenesis as a mechanism that mediated reduced tumor growth, metastasis, and mortality in individuals with Down syndrome. To confirm and extend these findings, we employed the complex cancer mouse model NPcis, which is heterozygous for the Trp53 and Nf1 genes and through LOH develops lymphomas, sarcomas, or carcinomas with 100% penetrance. In this aggressive model, trisomy did not prevent cancer, but it nevertheless extended host survival relative to euploid littermates. However, protection in this case was not attributable to either Ets2 dosage or to reduced angiogenesis. Together, our findings indicate that the genetic complexity underlying Down syndrome supports multiple mechanisms that contribute to reduced mortality from cancer. Cancer Res; 71(10); 3573–81. ©2011 AACR.
Data from Stromal Niche Cells Protect Early Leukemic FLT3-ITD+ Progenitor Cells against First-Generation FLT3 Tyrosine Kinase Inhibitors
Authors: Parmar Amanda , Marz Stefanie , Rushton Sally , Holzwarth Christina , Lind Katarina , Kayser Sabine , Döhner Konstanze , Peschel Christian , Oostendorp Robert A.J. , Götze Katharina S.
Published: March 2024

Abstract
Targeting constitutively activated FMS-like tyrosine kinase 3 [(FLT3); FLT3-ITD] with tyrosine kinase inhibitor (TKI) in acute myeloid leukemia (AML) leads to clearance of blasts in the periphery but not in the bone marrow, suggesting a protective effect of the marrow niche on leukemic stem cells. In this study, we examined the effect of stromal niche cells on CD34+ progenitors from patients with FLT3-ITD+ or wild-type FLT3 (FLT3-WT) AML treated with the TKIs SU5614 or sorafenib. TKIs effectively and specifically inhibited FLT3 and increased the fraction of undivided progenitors in both FLT3-ITD+ and FLT3-WT samples. Treatment with SU5614 and sorafenib also reduced the number of mature leukemic progenitors, whereas contact with stroma protected against this cell loss. In contrast, primitive long-term progenitors from both FLT3-ITD+ and FLT3-WT AML were resistant to TKIs. Additional contact with niche cells significantly expanded long-term FLT3-ITD+ but not FLT3-WT progenitors in the presence of SU5614 but not that of sorafenib. Thus, TKIs with first-generation inhibitors fail to eradicate early leukemic stem/progenitor cells in FLT3-ITD+ AML. Further, we defined a specific interaction between FLT3-ITD+ progenitors and niche cells that enables the maintenance of leukemic progenitors in the presence of TKI. Collectively, our findings suggest that molecular therapy may have unpredicted effects on leukemic progenitors, underscoring the necessity of developing strategies to selectively eliminate the malignant stem cell clone. Cancer Res; 71(13); 4696–706. ©2011 AACR.
Data from Human Glioma Growth Is Controlled by MicroRNA-10b
Authors: Gabriely Galina , Yi Ming , Narayan Ravi S. , Niers Johanna M. , Wurdinger Thomas , Imitola Jaime , Ligon Keith L. , Kesari Santosh , Esau Christine , Stephens Robert M. , Tannous Bakhos A. , Krichevsky Anna M.
Published: March 2024

Abstract
MicroRNA (miRNA) expression profiling studies revealed a number of miRNAs dysregulated in the malignant brain tumor glioblastoma. Molecular functions of these miRNAs in gliomagenesis are mainly unknown. We show that inhibition of miR-10b, a miRNA not expressed in human brain and strongly upregulated in both low-grade and high-grade gliomas, reduces glioma cell growth by cell-cycle arrest and apoptosis. These cellular responses are mediated by augmented expression of the direct targets of miR-10b, including BCL2L11/Bim, TFAP2C/AP-2γ, CDKN1A/p21, and CDKN2A/p16, which normally protect cells from uncontrolled growth. Analysis of The Cancer Genome Atlas expression data set reveals a strong positive correlation between numerous genes sustaining cellular growth and miR-10b levels in human glioblastomas, while proapoptotic genes anticorrelate with the expression of miR-10b. Furthermore, survival of glioblastoma patients expressing high levels of miR-10 family members is significantly reduced in comparison to patients with low miR-10 levels, indicating that miR-10 may contribute to glioma growth in vivo. Finally, inhibition of miR-10b in a mouse model of human glioma results in significant reduction of tumor growth. Altogether, our experiments validate an important role of miR-10b in gliomagenesis, reveal a novel mechanism of miR-10b–mediated regulation, and suggest the possibility of its future use as a therapeutic target in gliomas. Cancer Res; 71(10); 3563–72. ©2011 AACR.
Data from PGC1α Promotes Tumor Growth by Inducing Gene Expression Programs Supporting Lipogenesis
Authors: Bhalla Kavita , Hwang Bor Jang , Dewi Ruby E. , Ou Lihui , Twaddel William , Fang Hong-bin , Vafai Scott B. , Vazquez Francesca , Puigserver Pere , Boros Laszlo , Girnun Geoffrey D.
Published: March 2024

Abstract
Despite the role of aerobic glycolysis in cancer, recent studies highlight the importance of the mitochondria and biosynthetic pathways as well. PPARγ coactivator 1α (PGC1α) is a key transcriptional regulator of several metabolic pathways including oxidative metabolism and lipogenesis. Initial studies suggested that PGC1α expression is reduced in tumors compared with adjacent normal tissue. Paradoxically, other studies show that PGC1α is associated with cancer cell proliferation. Therefore, the role of PGC1α in cancer and especially carcinogenesis is unclear. Using Pgc1α−/− and Pgc1α+/+ mice, we show that loss of PGC1α protects mice from azoxymethane-induced colon carcinogenesis. Similarly, diethylnitrosamine-induced liver carcinogenesis is reduced in Pgc1α−/− mice as compared with Pgc1α+/+ mice. Xenograft studies using gain and loss of PGC1α expression showed that PGC1α also promotes tumor growth. Interestingly, while PGC1α induced oxidative phosphorylation and tricarboxylic acid cycle gene expression, we also observed an increase in the expression of two genes required for de novo fatty acid synthesis, ACC and FASN. In addition, SLC25A1 and ACLY, which are required for the conversion of glucose into acetyl-CoA for fatty acid synthesis, were also increased by PGC1α, thus linking the oxidative and lipogenic functions of PGC1α. Indeed, using stable 13C isotope tracer analysis, we show that PGC1α increased de novo lipogenesis. Importantly, inhibition of fatty acid synthesis blunted these progrowth effects of PGC1α. In conclusion, these studies show for the first time that loss of PGC1α protects against carcinogenesis and that PGC1α coordinately regulates mitochondrial and fatty acid metabolism to promote tumor growth. Cancer Res; 71(21); 6888–98. ©2011 AACR.
Data from IL-7 Contributes to the Progression of Human T-cell Acute Lymphoblastic Leukemias
Authors: Silva Ana , Laranjeira Angelo B.A. , Martins Leila R. , Cardoso Bruno A. , Demengeot Jocelyne , Yunes J. Andrés , Seddon Benedict , Barata João T.
Published: March 2024

Abstract
The importance of microenvironmental factors for driving progression in leukemia has been debated. Previous evidence has pointed to interleukin-7 (IL-7), a fundamental cytokine to normal T-cell development and homeostasis, as an important determinant of the viability and proliferation of T-cell acute lymphoblastic leukemia (T-ALL) cells in vitro. In this study, we report that IL-7 is also a critical determinant of T-ALL progression. T-ALL cell lines and primary T-ALL samples initiated leukemia more slowly when engrafted to immunocompromised Rag2−/−IL2rg−/− mice lacking IL-7. This effect was not related to reduced engraftment or homing of transplanted cells to the bone marrow. Instead, IL-7 deficiency diminished expansion of leukemia cells in the bone marrow and delayed leukemia-associated death of transplanted mice. Moreover, infiltration of different organs by T-ALL cells, which characterizes patients with advanced disease, was more heterogeneous and generally less efficient in IL-7–deficient mice. Leukemia progression was associated with increased Bcl-2 expression and cell viability, reduced p27Kip1 expression, and decreased cell-cycle progression. Clinical measurements of IL-7 plasma levels and IL-7 receptor (IL-7R) expression in T-ALL patients versus healthy controls confirmed that IL-7 stimulates human leukemia cells. Our results establish that IL-7 contributes to the progression of human T-cell leukemia, and they offer preclinical validation of the concept that targeting IL-7/IL-7R signaling in the tumor microenvironment could elicit therapeutic effects in T-ALL. Cancer Res; 71(14); 4780–9. ©2011 AACR.
Data from Localization and Density of Immune Cells in the Invasive Margin of Human Colorectal Cancer Liver Metastases Are Prognostic for Response to Chemotherapy
Authors: Halama Niels , Michel Sara , Kloor Matthias , Zoernig Inka , Benner Axel , Spille Anna , Pommerencke Thora , von Knebel Doeberitz Magnus , Folprecht Gunnar , Luber Birgit , Feyen Nadine , Martens Uwe M. , Beckhove Philipp , Gnjatic Sacha , Schirmacher Peter , Herpel Esther , Weitz Juergen , Grabe Niels , Jaeger Dirk
Published: March 2024

Abstract
Analysis of tumor-infiltrating lymphocytes (TIL) in primary human colorectal cancer (CRC) by in situ immunohistochemical staining supports the hypothesis that the adaptive immune response influences the course of human CRC. Specifically, high densities of TILs in the primary tumor are associated with good prognosis independent of other prognostic markers. However, the prognostic role of TILs in metastatic CRC lesions is unknown, as is their role in response or resistance to conventional chemotherapy. We analyzed the association of TIL densities at the invasive margin of CRC liver metastases with response to chemotherapy and progression-free survival in a set of 101 large section samples. High-resolution automated microscopy on complete tissue sections was used to objectively generate cell densities for CD3, CD8, granzyme B, or FOXP3 positive immune cells. A predictive scoring system using TIL densities was developed in a training set and tested successfully in an independent validation set. TIL densities at the invasive margin of liver metastases allowed the prediction of response to chemotherapy with a sensitivity of 79% and specificity of 100%. The association of high density values with longer progression-free survival under chemotherapy was statistically significant. Overall, these findings extend the impact of the local immune response on the clinical course from the primary tumor also to metastatic lesions. Because detailed quantification of TILs in metastatic lesions revealed a strong association with chemotherapy efficacy and prognosis, we suggest that the developed scoring system may be used as a predictive tool for response to chemotherapy in metastatic CRC. Cancer Res; 71(17); 5670–7. ©2011 AACR.
Data from IL-8 Signaling Plays a Critical Role in the Epithelial–Mesenchymal Transition of Human Carcinoma Cells
Authors: Fernando Romaine I. , Castillo Marianne D. , Litzinger Mary , Hamilton Duane H. , Palena Claudia
Published: March 2024

Abstract
The switch of tumor cells from an epithelial to a mesenchymal-like phenotype [designated as epithelial-to-mesenchymal transition (EMT)] is known to induce tumor cell motility and invasiveness, therefore promoting metastasis of solid carcinomas. Although multiple studies have focused on elucidating the signaling events that initiate this phenotypic switch, there has been so far no characterization of the pattern of soluble mediators released by tumor cells undergoing EMT, and the potential impact that this phenotypic switch could have on the remodeling of the tumor microenvironment. Here we show that induction of EMT in human carcinoma cells via overexpression of the transcription factor Brachyury is associated with enhanced secretion of multiple cytokines, chemokines, and angiogenic factors and, in particular, with the induction of the IL-8/IL-8R axis. Our results also indicate the essential role of interleukin 8 (IL-8) signaling for the acquisition and/or maintenance of the mesenchymal and invasive features of Brachyury-overexpressing tumor cells and show that IL-8 secreted by tumor cells undergoing EMT could potentiate tumor progression by inducing adjacent epithelial tumor cells into EMT. Altogether, our results emphasize the potential role of EMT in the modulation of the tumor microenvironment via secretion of multiple soluble mediators and suggest that IL-8 signaling blockade may provide a means of targeting mesenchymal-like, invasive tumor cells. Cancer Res; 71(15); 5296–306. ©2011 AACR.
Data from HOXC9 Links Cell-Cycle Exit and Neuronal Differentiation and Is a Prognostic Marker in Neuroblastoma
Authors: Mao Ling , Ding Jane , Zha Yunhong , Yang Liqun , McCarthy Brian A. , King William , Cui Hongjuan , Ding Han-Fei
Published: March 2024

Abstract
Differentiation status in neuroblastoma strongly affects clinical outcomes and inducing differentiation is a treatment strategy in this disease. However, the molecular mechanisms that control neuroblastoma differentiation are not well understood. Here, we show that high-level HOXC9 expression is associated with neuroblastoma differentiation and is prognostic for better survival in neuroblastoma patients. HOXC9 induces growth arrest and neuronal differentiation in neuroblastoma cells by directly targeting both cell-cycle–promoting and neuronal differentiation genes. HOXC9 expression is upregulated by retinoic acid (RA), and knockdown of HOXC9 expression confers resistance to RA-induced growth arrest and differentiation. Moreover, HOXC9 expression is epigenetically silenced in RA-resistant neuroblastoma cells, and forced HOXC9 expression is sufficient to inhibit their proliferation and tumorigenecity. These findings identified HOXC9 as a key regulator of neuroblastoma differentiation and suggested a therapeutic strategy for RA-resistant neuroblastomas through epigenetic activation of HOXC9 expression. Cancer Res; 71(12); 4314–24. ©2011 AACR.
Data from TLR9 Agonists Oppositely Modulate DNA Repair Genes in Tumor versus Immune Cells and Enhance Chemotherapy Effects
Authors: Sommariva Michele , De Cecco Loris , De Cesare Michelandrea , Sfondrini Lucia , Ménard Sylvie , Melani Cecilia , Delia Domenico , Zaffaroni Nadia , Pratesi Graziella , Uva Valentina , Tagliabue Elda , Balsari Andrea
Published: March 2024

Abstract
Synthetic oligodeoxynucleotides expressing CpG motifs (CpG-ODN) are a Toll-like receptor 9 (TLR9) agonist that can enhance the antitumor activity of DNA-damaging chemotherapy and radiation therapy in preclinical mouse models. We hypothesized that the success of these combinations is related to the ability of CpG-ODN to modulate genes involved in DNA repair. We conducted an in silico analysis of genes implicated in DNA repair in data sets obtained from murine colon carcinoma cells in mice injected intratumorally with CpG-ODN and from splenocytes in mice treated intraperitoneally with CpG-ODN. CpG-ODN treatment caused downregulation of DNA repair genes in tumors. Microarray analyses of human IGROV-1 ovarian carcinoma xenografts in mice treated intraperitoneally with CpG-ODN confirmed in silico findings. When combined with the DNA-damaging drug cisplatin, CpG-ODN significantly increased the life span of mice compared with individual treatments. In contrast, CpG-ODN led to an upregulation of genes involved in DNA repair in immune cells. Cisplatin-treated patients with ovarian carcinoma as well as anthracycline-treated patients with breast cancer who are classified as “CpG-like” for the level of expression of CpG-ODN modulated DNA repair genes have a better outcome than patients classified as “CpG-untreated-like,” indicating the relevance of these genes in the tumor cell response to DNA-damaging drugs. Taken together, the findings provide evidence that the tumor microenvironment can sensitize cancer cells to DNA-damaging chemotherapy, thereby expanding the benefits of CpG-ODN therapy beyond induction of a strong immune response. Cancer Res; 71(20); 6382–90. ©2011 AACR.
Data from XMRV: A New Virus in Prostate Cancer?
Authors: Aloia Amanda L. , Sfanos Karen S. , Isaacs William B. , Zheng Qizhi , Maldarelli Frank , De Marzo Angelo M. , Rein Alan
Published: March 2024

Abstract
Several recent articles have reported the presence of a gammaretrovirus, termed “XMRV” (xenotropic murine leukemia virus-related virus) in prostate cancers (PCa). If confirmed, this could have enormous implications for the detection, prevention, and treatment of PCa. However, other articles report failure to detect XMRV in PCa. We tested nearly 800 PCa samples, using a combination of real-time PCR and immunohistochemistry (IHC). The PCR reactions were simultaneously monitored for amplification of a single-copy human gene, to confirm the quality of the sample DNA and its suitability for PCR. Controls showed that the PCR assay could detect the XMRV in a single infected cell, even in the presence of a 10,000-fold excess of uninfected human cells. The IHC used 2 rabbit polyclonal antisera, each prepared against a purified murine leukemia virus (MLV) protein. Both antisera always stained XMRV-infected or -transfected cells, but never stained control cells. No evidence for XMRV in PCa was obtained in these experiments. We discuss possible explanations for the discrepancies in the results from different laboratories. It is possible that XMRV is not actually circulating in the human population; even if it is, the data do not seem to support a causal role for this virus in PCa. Cancer Res; 70(24); 10028–33. ©2010 AACR.
Data from Targeted Signal-Amplifying Enzymes Enhance MRI of EGFR Expression in an Orthotopic Model of Human Glioma
Authors: Shazeeb Mohammed S. , Sotak Christopher H. , DeLeo Michael , Bogdanov Alexei
Published: March 2024

Abstract
Epidermal growth factor receptor (EGFR) imaging in brain tumors is essential to visualize overexpression of EGFRvIII variants as a signature of highly aggressive gliomas and to identify patients that would benefit from anti-EGFR therapy. Seeking imaging improvements, we tested a novel pretargeting approach that relies on initial administration of enzyme-linked anti-EGFR monoclonal antibodies (mAb; EMD72000) followed by administration of a low-molecular-weight paramagnetic molecule (diTyr-GdDTPA) retained at the site of EGFR mAb accumulation. We hypothesized that diTyr-GdDTPA would become enzyme activated and retained on cells due to binding to tissue proteins. In support of this hypothesis, mAb-enzyme conjugates reacted with both membrane-isolated wild-type (wt) EGFR and EGFRvIII, but they bound primarily to EGFRvIII-expressing cells and not to EGFRwt-expressing cells. In vivo analysis of magnetic resonance (MR) tumor signal revealed differences in MR signal decay following diTyr-GdDTPA substrate administration. These differences were significant in that they suggested differences in substrate elimination from the tissue which relied on the specificity of the initial mAb binding: a biexponential signal decay was observed in tumors only upon preinjection with EGFR-targeted conjugates. Endpoint MRI in this setting revealed detailed images of tumors which correlated with immunohistochemical detection of EGFR expression. Together, our findings suggest an improved method to identify EGFRvIII-expressing gliomas in vivo that are best suited for treatment with therapeutic EGFR antibodies. Cancer Res; 71(6); 2230–9. ©2011 AACR.
Data from MMSET Is Highly Expressed and Associated with Aggressiveness in Neuroblastoma
Authors: Hudlebusch Heidi Rye , Skotte Julie , Santoni-Rugiu Eric , Zimling Zarah Glad , Lees Michael James , Simon Ronald , Sauter Guido , Rota Rossella , De Ioris Maria Antonietta , Quarto Micaela , Johansen Jens Vilstrup , Jørgensen Mette , Rechnitzer Catherine , Maroun Lisa Leth , Schrøder Henrik , Petersen Bodil Laub , Helin Kristian
Published: March 2024

Abstract
MMSET (WHSC1/NSD2) is a SET domain–containing histone lysine methyltransferase the expression of which is deregulated in a subgroup of multiple myelomas with the t(4;14)(p16;q32) translocation associated with poor prognosis. Recent studies have shown that MMSET mRNA levels are increased in other tumor types as well. We have carried out immunohistochemical staining of tissue microarrays and found that MMSET protein is frequently and highly expressed in neuroblastoma (MMSET positive in 75% of neuroblastomas, n = 164). The expression level of MMSET in neuroblastomas was significantly associated with poor survival, negative prognostic factors, and metastatic disease. Moreover, a subset of neuroblastomas for which pre- and postchemotherapy biopsies were available displayed a strong decrease in MMSET protein levels after chemotherapy. In agreement with neuroblastomas becoming more differentiated after treatment, we show that retinoic acid–induced differentiation of human neuroblastoma cells in vitro also leads to a strong decrease in MMSET levels. Furthermore, we show that the high levels of MMSET in normal neural progenitor cells are strongly downregulated during differentiation. Importantly, we show that MMSET is required for proliferation of neuroblastoma cells and brain-derived neural stem cells. Taken together, our results suggest that MMSET is implicated in neuroblastomagenesis possibly by supporting proliferation of progenitor cells and negatively regulating their differentiation. In this respect, MMSET might be a strong candidate therapeutic target in a subset of neuroblastomas with unfavorable prognosis. Cancer Res; 71(12); 4226–35. ©2011 AACR.
Data from A Novel Function of Junctional Adhesion Molecule-C in Mediating Melanoma Cell Metastasis
Authors: Langer Harald F. , Orlova Valeria V. , Xie Changping , Kaul Sunil , Schneider Darius , Lonsdorf Anke S. , Fahrleitner Manuela , Choi Eun Young , Dutoit Vanessa , Pellegrini Manuela , Grossklaus Sylvia , Nawroth Peter P. , Baretton Gustavo , Santoso Sentot , Hwang Sam T. , Arnold Bernd , Chavakis Triantafyllos
Published: March 2024

Abstract
Hematogenous dissemination of melanoma is a life-threatening complication of this malignant tumor. Here, we identified junctional adhesion molecule-C (JAM-C) as a novel player in melanoma metastasis to the lung. JAM-C expression was identified in human and murine melanoma cell lines, in human malignant melanoma, as well as in metastatic melanoma including melanoma lung metastasis. JAM-C expressed on both murine B16 melanoma cells as well as on endothelial cells promoted the transendothelial migration of the melanoma cells. We generated mice with inactivation of JAM-C. JAM-C−/− mice as well as endothelial-specific JAM-C–deficient mice displayed significantly decreased B16 melanoma cell metastasis to the lung, whereas treatment of mice with soluble JAM-C prevented melanoma lung metastasis. Together, JAM-C represents a novel therapeutic target for melanoma metastasis. Cancer Res; 71(12); 4096–105. ©2011 AACR.
Data from Does the Hepatitis B Antigen HBx Promote the Appearance of Liver Cancer Stem Cells?
Authors: Arzumanyan Alla , Friedman Tiffany , Ng Irene O.L. , Clayton Marcia M. , Lian Zhaorui , Feitelson Mark A.
Published: March 2024

Abstract
Hepatitis B virus (HBV) is a major etiologic agent of chronic liver disease and hepatocellular carcinoma (HCC). HBV-encoded X antigen, HBx, and pathways implicated in the self-renewal of stem cells contribute to HCC, but it is not clear whether HBx expression promotes “stemness.” Thus, experiments were designed to test the hypothesis that HBx triggers malignant transformation by promoting properties that are characteristic of cancer stem cells (CSC). To test this hypothesis, HepG2 cells were stably transduced with HBx and then assayed for phenotypic and molecular characteristics of “stemness.” The relationship between HBx and “stemness”-associated markers was also evaluated by immunohistochemical staining of liver and tumor tissue sections from HBV-infected patients. The results showed that Oct-4, Nanog, Klf-4, β-catenin, and epithelial cell adhesion molecule (EpCAM) were activated by HBx in vitro and in vivo. EpCAM was detected in the nuclei of human HCC cells from infected patients. HBx promotes “stemness” by activating β-catenin and epigenetic upregulation of miR-181, both of which target EpCAM. HBx expression was also associated with depressed levels of E-cadherin. Moreover, HBx stimulated cell migration, growth in soft agar, and spheroid formation. This work is the first to propose that HBV promotes “stemness” in the pathogenesis of HCC. HBx-associated upregulated expression of multiple “stemness” markers supports the hypothesis that HBx contributes to hepatocarcinogenesis, at least in part, by promoting changes in gene expression that are characteristics of CSCs. Cancer Res; 71(10); 3701–8. ©2011 AACR.
Data from Mast Cell Targeting Hampers Prostate Adenocarcinoma Development but Promotes the Occurrence of Highly Malignant Neuroendocrine Cancers
Authors: Pittoni Paola , Tripodo Claudio , Piconese Silvia , Mauri Giorgio , Parenza Mariella , Rigoni Alice , Sangaletti Sabina , Colombo Mario P.
Published: March 2024

Abstract
Mast cells (MC) are c-Kit–expressing cells, best known for their primary involvement in allergic reactions, but recently reappraised as important players in either cancer promotion or inhibition. Here, we assessed the role of MCs in prostate tumor development. In prostate tumors from both tumor-prone transgenic adenocarcinoma of the mouse prostate (TRAMP) mice and human patients, MCs are specifically enriched and degranulated in areas of well-differentiated (WD) adenocarcinoma but not around poorly differentiated (PD) foci that coexist in the same tumors. We derived novel TRAMP tumor cell lines, representative of WD and PD variants, and through pharmacologic stabilization or genetic ablation of MCs in recipients mice, we showed that MCs promote WD adenocarcinoma growth but are dispensable for PD tumors. WD tumors rely on MCs for matrix metalloprotease 9 (MMP-9) provision, as reconstitution of MC-deficient mice with wild-type but not MMP-9−/− MCs was sufficient to promote their growth. In contrast, PD tumors are MMP-9 self-competent, consistently with epithelial-to-mesenchymal transition. Such a dual source of MMP-9 was confirmed in human tumors, suggesting that MCs could be a good target for early-stage prostate cancer. Interestingly, in testing whether MC targeting could block or delay tumorigenesis in tumor-prone TRAMP mice, we observed a high incidence of early and aggressive tumors, characterized by a neuroendocrine (NE) signature and c-Kit expression. Taken together, these data underscore the contribution of MCs in tumor progression and uncover a new, opposite role of MCs in protecting against the occurrence of aggressive NE variants in prostate cancer. Cancer Res; 71(18); 5987–97. ©2011 AACR.
Data from A Drug Resistance Screen Using a Selective MET Inhibitor Reveals a Spectrum of Mutations That Partially Overlap with Activating Mutations Found in Cancer Patients
Authors: Tiedt Ralph , Degenkolbe Elisa , Furet Pascal , Appleton Brent A. , Wagner Sabrina , Schoepfer Joseph , Buck Emily , Ruddy David A. , Monahan John E. , Jones Michael D. , Blank Jutta , Haasen Dorothea , Drueckes Peter , Wartmann Markus , McCarthy Clive , Sellers William R. , Hofmann Francesco
Published: March 2024

Abstract
The emergence of drug resistance is a primary concern in any cancer treatment, including with targeted kinase inhibitors as exemplified by the appearance of Bcr-Abl point mutations in chronic myeloid leukemia (CML) patients treated with imatinib. In vitro approaches to identify resistance mutations in Bcr-Abl have yielded mutation spectra that faithfully recapitulated clinical observations. To predict resistance mutations in the receptor tyrosine kinase MET that could emerge during inhibitor treatment in patients, we conducted a resistance screen in BaF3 TPR-MET cells using the novel selective MET inhibitor NVP-BVU972. The observed spectrum of mutations in resistant cells was dominated by substitutions of tyrosine 1230 but also included other missense mutations and partially overlapped with activating MET mutations that were previously described in cancer patients. Cocrystallization of the MET kinase domain in complex with NVP-BVU972 revealed a key role for Y1230 in binding of NVP-BVU972, as previously reported for multiple other selective MET inhibitors. A second resistance screen in the same format with the MET inhibitor AMG 458 yielded a distinct spectrum of mutations rich in F1200 alterations, which is consistent with a different predicted binding mode. Our findings suggest that amino acid substitutions in the MET kinase domain of cancer patients need to be carefully monitored before and during treatment with MET inhibitors, as resistance may preexist or emerge. Compounds binding in the same manner as NVP-BVU972 might be particularly susceptible to the development of resistance through mutations in Y1230, a condition that may be addressed by MET inhibitors with alternative binding modes. Cancer Res; 71(15); 5255–64. ©2011 AACR.
Data from Role of Survivin in EGFR Inhibitor–Induced Apoptosis in Non–Small Cell Lung Cancers Positive for EGFR Mutations
Authors: Okamoto Kunio , Okamoto Isamu , Okamoto Wataru , Tanaka Kaoru , Takezawa Ken , Kuwata Kiyoko , Yamaguchi Haruka , Nishio Kazuto , Nakagawa Kazuhiko
Published: March 2024

Abstract
The molecular mechanism by which epidermal growth factor receptor–tyrosine kinase inhibitors (EGFR-TKI) induce apoptosis in non–small cell-lung cancer (NSCLC) cells that are positive for activating mutations of the EGFR remains unclear. In this study, we report the effects of the EGFR-TKI gefitinib on expression of the antiapoptotic protein survivin that have functional consequences in EGFR mutation–positive NSCLC cells. Immunoblot analysis revealed that gefitinib downregulated survivin expression, likely through inhibition of the PI3K-AKT signaling pathway, in NSCLC cells positive for EGFR mutation. Stable overexpression of survivin attenuated gefitinib-induced apoptosis and also inhibited the antitumor effect of gefitinib in human tumor xenografts. Furthermore, the combination of survivin overexpression with inhibition of the gefitinib-induced upregulation of the proapoptotic protein BIM attenuated gefitinib-induced apoptosis to a greater extent than either approach alone. Our results indicate that downregulation of survivin plays a pivotal role in gefitinib-induced apoptosis in EGFR mutation–positive NSCLC cells. Furthermore, they suggest that simultaneous interruption of the PI3K-AKT-survivin and MEK-ERK-BIM signaling pathways is responsible for EGFR-TKI–induced apoptotic death in these cells. Cancer Res; 70(24); 10402–10. ©2010 AACR.
Data from DLC1 Interaction with S100A10 Mediates Inhibition of In Vitro Cell Invasion and Tumorigenicity of Lung Cancer Cells through a RhoGAP-Independent Mechanism
Authors: Yang Xuyu , Popescu Nicholas C. , Zimonjic Drazen B.
Published: March 2024

Abstract
The DLC1 gene encodes a Rho GTPase-activating protein (RhoGAP) that functions as a tumor suppressor in several common human cancers. The multidomain structure of DLC1 enables interaction with a number of other proteins. Here we report that the proinflammatory protein S100A10 (also known as p11), a key cell surface receptor for plasminogen which regulates pericellular proteolysis and tumor cell invasion, is a new binding partner of DLC1 in human cells. We determined that the 2 proteins colocalize in the cell cytoplasm and that their binding is mediated by central sequences in the central domain of DLC1 and the C-terminus of S100A10. Because the same S100A10 sequence also mediates binding to Annexin 2, we found that DLC1 competed with Annexin 2 for interaction with S100A10. DLC1 binding to S100A10 did not affect DLC1's RhoGAP activity, but it decreased the steady-state level of S100A10 expression in a dose-dependent manner by displacing it from Annexin 2 and making it accessible to ubiquitin-dependent degradation. This process attenuated plasminogen activation and resulted in inhibition of in vitro cell migration, invasion, colony formation, and anchorage-independent growth of aggressive lung cancer cells. These results suggest that a novel GAP-independent mechanism contributes to the tumor suppressive activity of DLC1, and highlight the importance and complexity of protein–protein interactions involving DLC1 in certain cancers. Cancer Res; 71(8); 2916–25. ©2011 AACR.
Data from Dose-Dependent Effects of Focal Fractionated Irradiation on Secondary Malignant Neoplasms in Nf1 Mutant Mice
Authors: Nakamura Jean L. , Phong Connie , Pinarbasi Emile , Kogan Scott C. , Vandenberg Scott , Horvai Andrew E. , Faddegon Bruce A. , Fiedler Dorothea , Shokat Kevan , Houseman Benjamin T. , Chao Richard , Pieper Russell O. , Shannon Kevin
Published: March 2024

Abstract
Secondary malignant neoplasms (SMN) are increasingly common complications of cancer therapy that have proven difficult to model in mice. Clinical observations suggest that the development of SMN correlates with radiation dose; however, this relationship has not been investigated systematically. We developed a novel procedure for administering fractionated cranial irradiation (CI) and investigated the incidence and spectrum of cancer in control and heterozygous Nf1 mutant mice irradiated to a moderate (15 Gy) or high dose (30 Gy). Heterozygous Nf1 inactivation cooperated with CI to induce solid tumors and myeloid malignancies, with mice developing many of the most common SMNs found in human patients. CI-induced malignancies segregated according to radiation dose as Nf1+/− mice developed predominately hematologic abnormalities after 15 Gy, whereas solid tumors predominated at 30 Gy, suggesting that radiation dose thresholds exist for hematologic and nonhematologic cancers. Genetic and biochemical studies revealed discrete patterns of somatic Nf1 and Trp53 inactivation and we observed hyperactive Ras signaling in many radiation-induced solid tumors. This technique for administering focal fractionated irradiation will facilitate mechanistic and translational studies of SMNs. Cancer Res; 71(1); 106–15. ©2011 AACR.
Data from CXCL12/CXCR4 Blockade Induces Multimodal Antitumor Effects That Prolong Survival in an Immunocompetent Mouse Model of Ovarian Cancer
Authors: Righi Elda , Kashiwagi Satoshi , Yuan Jianping , Santosuosso Michael , Leblanc Pierre , Ingraham Rachel , Forbes Benjamin , Edelblute Beth , Collette Brian , Xing Deyin , Kowalski Magdalena , Mingari Maria Cristina , Vianello Fabrizio , Birrer Michael , Orsulic Sandra , Dranoff Glenn , Poznansky Mark C.
Published: March 2024

Abstract
The chemokine CXCL12 and its receptor CXCR4 are expressed widely in human cancers, including ovarian cancer, in which they are associated with disease progression at the levels of tumor cell proliferation, invasion, and angiogenesis. Here, we used an immunocompetent mouse model of intraperitoneal papillary epithelial ovarian cancer to show that modulation of the CXCL12/CXCR4 axis in ovarian cancer has multimodal effects on tumor pathogenesis associated with induction of antitumor immunity. siRNA-mediated knockdown of CXCL12 in BR5-1 cells that constitutively express CXCL12 and CXCR4 reduced cell proliferation in vitro, and tumor growth in vivo. Similarly, treatment of BR5-1–derived tumors with AMD3100, a selective CXCR4 antagonist, resulted in increased tumor apoptosis and necrosis, reduction in intraperitoneal dissemination, and selective reduction of intratumoral FoxP3+ regulatory T cells (Treg). Compared with controls, CXCR4 blockade greatly increased T-cell–mediated antitumor immune responses, conferring a significant survival advantage to AMD3100-treated mice. In addition, the selective effect of CXCR4 antagonism on intratumoral Tregs was associated with both higher CXCR4 expression and increased chemotactic responses to CXCL12, a finding that was also confirmed in a melanoma model. Together, our findings reinforce the concept of a critical role for the CXCL12/CXCR4 axis in ovarian cancer pathogenesis, and they offer a definitive preclinical validation of CXCR4 as a therapeutic target in this disease. Cancer Res; 71(16); 5522–34. ©2011 AACR.
Data from Epidermal Growth Factor Receptor Expression Identifies Functionally and Molecularly Distinct Tumor-Initiating Cells in Human Glioblastoma Multiforme and Is Required for Gliomagenesis
Authors: Mazzoleni Stefania , Politi Letterio S. , Pala Mauro , Cominelli Manuela , Franzin Alberto , Sergi Sergi Lucia , Falini Andrea , De Palma Michele , Bulfone Alessandro , Poliani Pietro L. , Galli Rossella
Published: March 2024

Abstract
Epidermal growth factor receptor (EGFR) is a known diagnostic and, although controversial, prognostic marker of human glioblastoma multiforme (GBM). However, its functional role and biological significance in GBM remain elusive. Here, we show that multiple GBM cell subpopulations could be purified from the specimens of patients with GBM and from cancer stem cell (CSC) lines based on the expression of EGFR and of other putative CSC markers. All these subpopulations are molecularly and functionally distinct, are tumorigenic, and need to express EGFR to promote experimental tumorigenesis. Among them, EGFR-expressing tumor-initiating cells (TIC) display the most malignant functional and molecular phenotype. Accordingly, modulation of EGFR expression by gain-of-function and loss-of-function strategies in GBM CSC lines enhances and reduces their tumorigenic ability, respectively, suggesting that EGFR plays a fundamental role in gliomagenesis. These findings open up the possibility of new therapeutically relevant scenarios, as the presence of functionally heterogeneous EGFRpos and EGFRneg TIC subpopulations within the same tumor might affect clinical response to treatment. Cancer Res; 70(19); 7500–13. ©2010 AACR.