bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Molecular Imaging with Bioluminescence and PET Reveals Viral Oncolysis Kinetics and Tumor Viability
Authors: Kuruppu Darshini , Brownell Anna-Liisa , Shah Khalid , Mahmood Umar , Tanabe Kenneth K.
Published: March 2024

Abstract
Viral oncolysis, the destruction of cancer cells by replicating virus, is an experimental cancer therapy that continues to be explored. The treatment paradigm for this therapy involves successive waves of lytic replication in cancer cells. At present, monitoring viral titer at sites of replication requires biopsy. However, repeat serial biopsies are not practically feasible for temporal monitoring of viral replication and tumor response in patients. Molecular imaging provides a noninvasive method to identify intracellular viral gene expression in real time. We imaged viral oncolysis and tumor response to oncolysis sequentially with bioluminescence and positron emission tomography (PET), revealing the kinetics of both processes in tumor xenografts. We demonstrate that virus replication cycles can be identified as successive waves of reporter expression that occur ∼2 days after the initial viral tumor infection peak. These waves correspond to virions that are released following a replication cycle. The viral and cellular kinetics were imaged with Fluc and Rluc bioluminescence reporters plus two 18F-labeled PET reporters FHBG [9-(4-18F-fluoro-3-[hydroxymethyl] butyl) guanine] and FLT (18F-3′-deoxy-3-′fluorothymidine), respectively. Correlative immunohistochemistry on tumor xenograft sections confirmed in vivo results. Our findings show how PET can be used to identify virus replication cycles and for real-time measurements of intratumoral replicating virus levels. This noninvasive imaging approach has potential utility for monitoring viral oncolysis therapy in patients. Cancer Res; 74(15); 4111–21. ©2014 AACR.
Data from CD47 in the Tumor Microenvironment Limits Cooperation between Antitumor T-cell Immunity and Radiotherapy
Authors: Soto-Pantoja David R. , Terabe Masaki , Ghosh Arunima , Ridnour Lisa A. , DeGraff William G. , Wink David A. , Berzofsky Jay A. , Roberts David D.
Published: March 2024

Abstract
Although significant advances in radiotherapy have increased its effectiveness in many cancer settings, general strategies to widen the therapeutic window between normal tissue toxicity and malignant tumor destruction would still offer great value. CD47 blockade has been found to confer radioprotection to normal tissues while enhancing tumor radiosensitivity. Here, we report that CD47 blockade directly enhances tumor immunosurveillance by CD8+ T cells. Combining CD47 blockade with irradiation did not affect fibrosarcoma growth in T cell–deficient mice, whereas adoptive transfer of tumor-specific CD8+ T cells restored combinatorial efficacy. Furthermore, ablation of CD8+ T cells abolished radiotherapeutic response in immunocompetent syngeneic hosts. CD47 blockade in either target cells or effector cells was sufficient to enhance antigen-dependent CD8+ CTL-mediated tumor cell killing in vitro. In CD47-deficient syngeneic hosts, engrafted B16 melanomas were 50% more sensitive to irradiation, establishing that CD47 expression in the microenvironment was sufficient to limit tumor radiosensitivity. Mechanistic investigations revealed increased tumor infiltration by cytotoxic CD8+ T cells in a CD47-deficient microenvironment, with an associated increase in T cell–dependent intratumoral expression of granzyme B. Correspondingly, an inverse correlation between CD8+ T-cell infiltration and CD47 expression was observed in human melanomas. Our findings establish that blocking CD47 in the context of radiotherapy enhances antitumor immunity by directly stimulating CD8+ cytotoxic T cells, with the potential to increase curative responses. Cancer Res; 74(23); 6771–83. ©2014 AACR.
Data from The RAC1 P29S Hotspot Mutation in Melanoma Confers Resistance to Pharmacological Inhibition of RAF
Authors: Watson Ian R. , Li Liren , Cabeceiras Peter K. , Mahdavi Mozhdeh , Gutschner Tony , Genovese Giannicola , Wang Guocan , Fang Zhuangna , Tepper James M. , Stemke-Hale Katherine , Tsai Kenneth Y. , Davies Michael A. , Mills Gordon B. , Chin Lynda
Published: March 2024

Abstract
Following mutations in BRAF and NRAS, the RAC1 c.85C>T single-nucleotide variant (SNV) encoding P29S amino acid change represents the next most frequently observed protein-coding hotspot mutation in melanoma. However, the biologic and clinical significance of the RAC1 P29S somatic mutation in approximately 4% to 9% of patients remains unclear. Here, we demonstrate that melanoma cell lines possessing the RAC1 hotspot variant are resistant to RAF inhibitors (vemurafenib and dabrafenib). Enforced expression of RAC1 P29S in sensitive BRAF-mutant melanoma cell lines confers resistance manifested by increased viability, decreased apoptosis, and enhanced tumor growth in vivo upon treatment with RAF inhibitors. Conversely, RNAi-mediated silencing of endogenous RAC1 P29S in a melanoma cell line with a co-occurring BRAF V600 mutation increased sensitivity to vemurafenib and dabrafenib. Our results suggest RAC1 P29S status may offer a predictive biomarker for RAF inhibitor resistance in melanoma patients, where it should be evaluated clinically. Cancer Res; 74(17); 4845–52. ©2014 AACR.
Data from HTLV-1 bZIP Factor HBZ Promotes Cell Proliferation and Genetic Instability by Activating OncomiRs
Authors: Vernin Céline , Thenoz Morgan , Pinatel Christiane , Gessain Antoine , Gout Olivier , Delfau-Larue Marie-Hélène , Nazaret Nicolas , Legras-Lachuer Catherine , Wattel Eric , Mortreux Franck
Published: March 2024

Abstract
Viruses disrupt the host cell microRNA (miRNA) network to facilitate their replication. Human T-cell leukemia virus type I (HTLV-1) replication relies on the clonal expansion of its host CD4+ and CD8+ T cells, yet this virus causes adult T-cell leukemia/lymphoma (ATLL) that typically has a CD4+ phenotype. The viral oncoprotein Tax, which is rarely expressed in ATLL cells, has long been recognized for its involvement in tumor initiation by promoting cell proliferation, genetic instability, and miRNA dysregulation. Meanwhile, HBZ is expressed in both untransformed infected cells and ATLL cells and is involved in sustaining cell proliferation and silencing virus expression. Here, we show that an HBZ–miRNA axis promotes cell proliferation and genetic instability, as indicated by comet assays that showed increased numbers of DNA-strand breaks. Expression profiling of miRNA revealed that infected CD4+ cells, but not CD8+ T cells, overexpressed oncogenic miRNAs, including miR17 and miR21. HBZ activated these miRNAs via a posttranscriptional mechanism. These effects were alleviated by knocking down miR21 or miR17 and by ectopic expression of OBFC2A, a DNA-damage factor that is downregulated by miR17 and miR21 in HTLV-1–infected CD4+ T cells. These findings extend the oncogenic potential of HBZ and suggest that viral expression might be involved in the remarkable genetic instability of ATLL cells. Cancer Res; 74(21); 6082–93. ©2014 AACR.
Data from Molecular Changes in Lobular Breast Cancers in Response to Endocrine Therapy
Authors: Arthur Laura M. , Turnbull Arran K. , Webber Victoria L. , Larionov Alexey A. , Renshaw Lorna , Kay Charlene , Thomas Jeremy S. , Dixon J. Michael , Sims Andrew H.
Published: March 2024

Abstract
Invasive lobular carcinoma (ILC) accounts for approximately 10% to 15% of breast carcinomas, and although it responds poorly to neoadjuvant chemotherapy, it appears to respond well to endocrine therapy. Pre- and on-treatment (after 2 weeks and 3 months) biopsies and surgical samples were obtained from 14 postmenopausal women with estrogen receptor–positive (ER+) histologically confirmed ILC who responded to 3 months of neoadjuvant letrozole and were compared with a cohort of 14 responding invasive ductal carcinomas (IDC) matched on clinicopathologic features. RNA was extracted and processed for whole human genome expression microarray. Dynamic clinical response was assessed using periodic three-dimensional ultrasound measurements performed during treatment and defined as a reduction of >70% in tumor volume by 3 months. Pretreatment profiles of ILC and IDC tumors showed distinctive expression of genes associated with E-cadherin signaling, epithelial adhesion, and stromal rearrangement. The changes in gene expression in response to letrozole were highly similar between responding ILC and IDC tumors; genes involved in proliferation were downregulated and those involved with immune function and extracellular matrix remodeling were upregulated. However, molecular differences between the histologic subtypes were maintained upon treatment. This is the first study of molecular changes in ILC in response to endocrine therapy to date. The genes that change on letrozole are highly consistent between ILC and IDC. Differences in gene expression between ILC and IDC at diagnosis are maintained at each time point on treatment. Cancer Res; 74(19); 5371–6. ©2014 AACR.
Data from Translesion Polymerase η Is Upregulated by Cancer Therapeutics and Confers Anticancer Drug Resistance
Authors: Tomicic Maja T. , Aasland Dorthe , Naumann Steffen C. , Meise Ruth , Barckhausen Christina , Kaina Bernd , Christmann Markus
Published: March 2024

Abstract
DNA repair processes are a key determinant of the sensitivity of cancer cells to DNA-damaging chemotherapeutics, which may induce certain repair genes as a mechanism to promote resistance. Here, we report the results of a screen for repair genes induced in cancer cells treated with DNA crosslinking agents, which identified the translesion polymerase η (PolH) as a p53-regulated target acting as one defense against interstrand crosslink (ICL)-inducing agents. PolH was induced by fotemustine, mafosfamide, and lomustine in breast cancer, glioma, and melanoma cells in vitro and in vivo, with similar inductions observed in normal cells such as lymphocytes and diploid fibroblasts. PolH contributions to the protection against ICL-inducing agents were evaluated by its siRNA-mediated attenuation in cells, which elevated sensitivity to these drugs in all tumor cell models. Conversely, PolH overexpression protected cancer cells against these drugs. PolH attenuation reduced repair of ICL lesions as measured by host cell reactivation assays and enhanced persistence of γH2AX foci. Moreover, we observed a strong accumulation of PolH in the nucleus of drug-treated cells along with direct binding to damaged DNA. Taken together, our findings implicated PolH in ICL repair as a mechanism of cancer drug resistance and normal tissue protection. Cancer Res; 74(19); 5585–96. ©2014 AACR.
Data from Zfx Facilitates Tumorigenesis Caused by Activation of the Hedgehog Pathway
Authors: Palmer Colin J. , Galan-Caridad Jose M. , Weisberg Stuart P. , Lei Liang , Esquilin Jose M. , Croft Gist F. , Wainwright Brandon , Canoll Peter , Owens David M. , Reizis Boris
Published: March 2024

Abstract
The Hedgehog (Hh) signaling pathway regulates normal development and cell proliferation in metazoan organisms, but its aberrant activation can promote tumorigenesis. Hh-induced tumors arise from various tissues and they may be indolent or aggressive, as is the case with skin basal cell carcinoma (BCC) or cerebellar medulloblastoma, respectively. Little is known about common cell-intrinsic factors that control the development of such diverse Hh-dependent tumors. Transcription factor Zfx is required for the self-renewal of hematopoietic and embryonic stem cells, as well as for the propagation of acute myeloid and T-lymphoblastic leukemias. We report here that Zfx facilitates the development of experimental BCC and medulloblastoma in mice initiated by deletion of the Hh inhibitory receptor Ptch1. Simultaneous deletion of Zfx along with Ptch1 prevented BCC formation and delayed medulloblastoma development. In contrast, Zfx was dispensable for tumorigenesis in a mouse model of glioblastoma. We used genome-wide expression and chromatin-binding analysis in a human medulloblastoma cell line to characterize direct, evolutionarily conserved targets of Zfx, identifying Dis3L and Ube2j1 as two targets required for the growth of the human medulloblastoma cells. Our results establish Zfx as a common cell-intrinsic regulator of diverse Hh-induced tumors, with implications for the definition of new therapeutic targets in these malignancies. Cancer Res; 74(20); 5914–24. ©2014 AACR.
Data from IDH2 and NPM1 Mutations Cooperate to Activate Hoxa9/Meis1 and Hypoxia Pathways in Acute Myeloid Leukemia
Authors: Ogawara Yoko , Katsumoto Takuo , Aikawa Yukiko , Shima Yutaka , Kagiyama Yuki , Soga Tomoyoshi , Matsunaga Hironori , Seki Takahiko , Araki Kazushi , Kitabayashi Issay
Published: March 2024

Abstract
IDH1 and IDH2 mutations occur frequently in acute myeloid leukemia (AML) and other cancers. The mutant isocitrate dehydrogenase (IDH) enzymes convert α-ketoglutarate (α-KG) to the oncometabolite 2-hydroxyglutarate (2-HG), which dysregulates a set of α-KG–dependent dioxygenases. To determine whether mutant IDH enzymes are valid targets for cancer therapy, we created a mouse model of AML in which mice were transplanted with nucleophosmin1 (NPM)+/− hematopoietic stem/progenitor cells cotransduced with four mutant genes (NPMc, IDH2/R140Q, DNMT3A/R882H, and FLT3/ITD), which often occur simultaneously in human AML patients. Conditional deletion of IDH2/R140Q blocked 2-HG production and maintenance of leukemia stem cells, resulting in survival of the AML mice. IDH2/R140Q was necessary for the engraftment or survival of NPMc+ cells in vivo. Gene expression analysis indicated that NPMc increased expression of Hoxa9. IDH2/R140Q also increased the level of Meis1 and activated the hypoxia pathway in AML cells. IDH2/R140Q decreased the 5hmC modification and expression of some differentiation-inducing genes (Ebf1 and Spib). Taken together, our results indicated that IDH2 mutation is critical for the development and maintenance of AML stem-like cells, and they provided a preclinical justification for targeting mutant IDH enzymes as a strategy for anticancer therapy. Cancer Res; 75(10); 2005–16. ©2015 AACR.
Data from A TDO2-AhR Signaling Axis Facilitates Anoikis Resistance and Metastasis in Triple-Negative Breast Cancer
Authors: D'Amato Nicholas C. , Rogers Thomas J. , Gordon Michael A. , Greene Lisa I. , Cochrane Dawn R. , Spoelstra Nicole S. , Nemkov Travis G. , D'Alessandro Angelo , Hansen Kirk C. , Richer Jennifer K.
Published: March 2024

Abstract
The ability of a cancer cell to develop resistance to anoikis, a programmed cell death process triggered by substratum detachment, is a critical step in the metastatic cascade. Triple-negative breast cancers (TNBC) exhibit higher rates of metastasis after diagnosis, relative to estrogen-positive breast cancers, but while TNBC cells are relatively more resistant to anoikis, the mechanisms involved are unclear. Through gene expression and metabolomic profiling of TNBC cells in forced suspension culture, we identified a molecular pathway critical for anchorage-independent cell survival. TNBC cells in suspension upregulated multiple genes in the kynurenine pathway of tryptophan catabolism, including the enzyme tryptophan 2,3-dioxygenase (TDO2), in an NF-κB–dependent manner. Kynurenine production mediated by TDO2 in TNBC cells was sufficient to activate aryl hydrocarbon receptor (AhR), an endogenous kynurenine receptor. Notably, pharmacologic inhibition or genetic attenuation of TDO2 or AhR increased cellular sensitivity to anoikis, and also reduced proliferation, migration, and invasion of TNBC cells. In vivo, TDO2 inhibitor–treated TNBC cells inhibited colonization of the lung, suggesting that TDO2 enhanced metastatic capacity. In clinical specimens of TNBC, elevated expression of TDO2 was associated with increased disease grade, estrogen receptor–negative status, and shorter overall survival. Our results define an NF-κB–regulated signaling axis that promotes anoikis resistance, suggest functional connections with inflammatory modulation by the kynurenine pathway, and highlight TDO2 as an attractive target for treatment of this aggressive breast cancer subtype. Cancer Res; 75(21); 4651–64. ©2015 AACR.
Data from Genetic Identification of SEMA3F as an Antilymphangiogenic Metastasis Suppressor Gene in Head and Neck Squamous Carcinoma
Authors: Doçi Colleen L. , Mikelis Constantinos M. , Lionakis Michail S. , Molinolo Alfredo A. , Gutkind J. Silvio
Published: March 2024

Abstract
Head and neck squamous cell carcinomas (HNSCC) often metastasize to locoregional lymph nodes, and lymph node involvement represents one of the most important prognostic factors of poor clinical outcome. HNSCCs are remarkably lymphangiogenic and represent a clear example of a cancer that utilizes the lymphatic vasculature for malignant dissemination; however, the molecular mechanisms underlying lymphangiogenesis in HNSCC is still poorly understood. Of interest, we found that an axon guidance molecule, Semaphorin 3F (SEMA3F), is among the top 1% underexpressed genes in HNSCC, and that genomic loss of SEMA3F correlates with increased metastasis and decreased survival. SEMA3F acts on its coreceptors, plexins and neuropilins, among which neuropilin-2 (NRP2) is highly expressed in lymphatic endothelial cells (LEC) but not in oral epithelium and most HNSCCs. We show that recombinant SEMA3F promotes LEC collapse and potently inhibits lymphangiogenesis in vivo. By reconstituting all possible plexin and neuropilin combinations, we found that SEMA3F acts through multiple receptors, but predominantly requires NRP2 to signal in LECs. Using orthotopic HNSCC metastasis mouse models, we provide direct evidence that SEMA3F re-expression diminishes lymphangiogenesis and lymph node metastasis. Furthermore, analysis of a large tissue collection revealed that SEMA3F is progressively lost during HNSCC progression, concomitant with increased tumor lymphangiogenesis. SEMA3F is localized to 3p21, an early and frequently deleted locus in HNSCC and many other prevalent human malignancies. Thus, SEMA3F may represent an antilymphangiogenic metastasis suppressor gene widely lost during cancer progression, hence serving as a prognostic biomarker and an attractive target for therapeutic intervention to halt metastasis. Cancer Res; 75(14); 2937–48. ©2015 AACR.
Data from Proteolysis of EphA2 Converts It from a Tumor Suppressor to an Oncoprotein
Authors: Koshikawa Naohiko , Hoshino Daisuke , Taniguchi Hiroaki , Minegishi Tomoko , Tomari Taizo , Nam Sung-Ouk , Aoki Mikiko , Sueta Takayuki , Nakagawa Takashi , Miyamoto Shingo , Nabeshima Kazuki , Weaver Alissa M. , Seiki Motoharu
Published: March 2024

Abstract
Eph receptor tyrosine kinases are considered candidate therapeutic targets in cancer, but they can exert opposing effects on cell growth. In the presence of its ligands, Eph receptor EphA2 suppresses signaling by other growth factor receptors, including ErbB, whereas ligand-independent activation of EphA2 augments ErbB signaling. To deploy EphA2-targeting drugs effectively in tumors, the anti-oncogenic ligand-dependent activation state of EphA2 must be discriminated from its oncogenic ligand-independent state. Because the molecular basis for the latter is little understood, we investigated how the activation state of EphA2 can be switched in tumor tissue. We found that ligand-binding domain of EphA2 is cleaved frequently by the membrane metalloproteinase MT1-MMP, a powerful modulator of the pericellular environment in tumor cells. EphA2 immunostaining revealed a significant loss of the N-terminal portion of EphA2 in areas of tumor tissue that expressed MT1-MMP. Moreover, EphA2 phosphorylation patterns that signify ligand-independent activation were observed specifically in these areas of tumor tissue. Mechanistic experiments revealed that processing of EphA2 by MT1-MMP promoted ErbB signaling, anchorage-independent growth, and cell migration. Conversely, expression of a proteolysis-resistant mutant of EphA2 prevented tumorigenesis and metastasis of human tumor xenografts in mice. Overall, our results showed how the proteolytic state of EphA2 in tumors determines its effector function and influences its status as a candidate biomarker for targeted therapy. Cancer Res; 75(16); 3327–39. ©2015 AACR.
Data from Cell–Cell Adhesion and Cytoskeleton Tension Oppose Each Other in Regulating Tumor Cell Aggregation
Authors: Saias Laure , Gomes Aurélie , Cazales Martine , Ducommun Bernard , Lobjois Valérie
Published: March 2024

Abstract
Cell aggregation is frequently impaired during the growth of primary tumors and the formation of metastatic lesions. Cell aggregation depends on cell–cell adhesion; however, no rigorous approach exists to monitor and quantify it accurately in the absence of the confounding factors of cell–substrate adhesion and the resulting cell motility on the substrate. We report here a highly reproducible, automated, microscopy-based quantification of tumor-cell spheroid formation in the absence of cell–substrate adhesion and use it to characterize cell aggregation dynamics in the early steps of this process. This method is based on fluorescence and bright-field microscopy and on a custom MATLAB program to quantify automatically the cells' aggregation kinetics. We demonstrate that the cell–cell adhesion protein E-cadherin and the desmosome proteins DSG2 and DSC2 are important for aggregation. Furthermore, we show that inhibition or silencing of myosin IIa enhances aggregation, suggesting that cytoskeleton tension inhibits tumor cell aggregation. This work opens new avenues to study the principles that govern multicellular aggregation, to characterize the aggregation properties of various tumor cell types, as well as to screen for drugs that inhibit or promote aggregation. Cancer Res; 75(12); 2426–33. ©2015 AACR.
Data from Metastatic Competence Can Emerge with Selection of Preexisting Oncogenic Alleles without a Need of New Mutations
Authors: Jacob Leni S. , Vanharanta Sakari , Obenauf Anna C. , Pirun Mono , Viale Agnes , Socci Nicholas D. , Massagué Joan
Published: March 2024

Abstract
Several experimental models faithfully recapitulate many important facets of human metastatic disease. Here, we have performed whole-exome sequencing in five widely used experimental metastasis models that were independently derived through in vivo selection from heterogeneous human cancer cell lines. In addition to providing an important characterization of these model systems, our study examines the genetic evolution of metastatic phenotypes. We found that in vivo selected highly metastatic cell populations showed little genetic divergence from the corresponding parental population. However, selection of genetic variations that preexisted in parental populations, including the well-established oncogenic mutations KRASG13D and BRAFG464V, was associated with increased metastatic capability. Conversely, expression of the wild-type BRAF allele in metastatic cells inhibited metastatic outgrowth as well as tumor initiation in mice. Our findings establish that metastatic competence can arise from heterogeneous cancer cell populations without the need for acquisition of additional mutations and that such competence can benefit from further selection of tumor-initiating mutations that seed primary tumorigenesis. Cancer Res; 75(18); 3713–9. ©2015 AACR.
Data from Enhanced Chemokine Receptor Recycling and Impaired S1P1 Expression Promote Leukemic Cell Infiltration of Lymph Nodes in Chronic Lymphocytic Leukemia
Authors: Patrussi Laura , Capitani Nagaja , Martini Veronica , Pizzi Marco , Trimarco Valentina , Frezzato Federica , Marino Filippo , Semenzato Gianpietro , Trentin Livio , Baldari Cosima T.
Published: March 2024

Abstract
Lymphocyte trafficking is orchestrated by chemokine and sphingosine 1-phosphate (S1P) receptors that enable homing and egress from secondary lymphoid organs (SLO). These receptors undergo rapid internalization and plasma membrane recycling to calibrate cellular responses to local chemoattractants. Circulating chronic lymphocytic leukemia (CLL) cells display an abnormal increase in the surface levels of the homing receptors CCR7 and CXCR4 concomitant with low S1P receptor 1 (S1P1) expression. In this study, we investigated the role of receptor recycling on CXCR4/CCR7 surface levels in CLL cells and addressed the impact of quantitative alterations of these receptors and S1P1 on the ability of leukemic cells to accumulate in SLOs. We show that recycling accounts, to a major extent, for the high levels of surface CXCR4/CCR7 on CLL cells. In addition, increased expression of these receptors, together with S1P1 deficiency, is detectable not only in circulating leukemic cells, but also in SLOs of CLL patients with lymphoadenopathy. We further provide evidence that ibrutinib, a Btk inhibitor that promotes mobilization of leukemic cells from SLOs, normalizes the imbalance between CXCR4/CCR7 and S1P1. Taken together, our results highlight the relevance of chemokine and S1P receptor recycling in CLL pathogenesis and clinical outcome. Cancer Res; 75(19); 4153–63. ©2015 AACR.
Data from Investigation of Optical Coherence Microelastography as a Method to Visualize Cancers in Human Breast Tissue
Authors: Kennedy Brendan F. , McLaughlin Robert A. , Kennedy Kelsey M. , Chin Lixin , Wijesinghe Philip , Curatolo Andrea , Tien Alan , Ronald Maxine , Latham Bruce , Saunders Christobel M. , Sampson David D.
Published: March 2024

Abstract
An accurate intraoperative identification of malignant tissue is a challenge in the surgical management of breast cancer. Imaging techniques that help address this challenge could contribute to more complete and accurate tumor excision, and thereby help reduce the current high reexcision rates without resorting to the removal of excess healthy tissue. Optical coherence microelastography (OCME) is a three-dimensional, high-resolution imaging technique that is sensitive to microscale variations of the mechanical properties of tissue. As the tumor modifies the mechanical properties of breast tissue, OCME has the potential to identify, on the microscale, involved regions of fresh, unstained tissue. OCME is based on the use of optical coherence tomography (OCT) to measure tissue deformation in response to applied mechanical compression. In this feasibility study on 58 ex vivo samples from patients undergoing mastectomy or wide local excision, we demonstrate the performance of OCME as a means to visualize tissue microarchitecture in benign and malignant human breast tissues. Through a comparison with corresponding histology and OCT images, OCME is shown to enable ready visualization of features such as ducts, lobules, microcysts, blood vessels, and arterioles and to identify invasive tumor through distinctive patterns in OCME images, often with enhanced contrast compared with OCT. These results lay the foundation for future intraoperative studies. Cancer Res; 75(16); 3236–45. ©2015 AACR.
Data from PAD2 Overexpression in Transgenic Mice Promotes Spontaneous Skin Neoplasia
Authors: McElwee John L. , Mohanan Sunish , Horibata Sachi , Sams Kelly L. , Anguish Lynne J. , McLean Dalton , Cvitaš Iva , Wakshlag Joseph J. , Coonrod Scott A.
Published: March 2024

Abstract
Peptidylarginine deiminase 2 (PAD2/PADI2) has been implicated in various inflammatory diseases and, more recently, cancer. The goal of this study was to test the hypothesis that PAD2 promotes oncogenesis using a transgenic mouse model. We found that about 37% of transgenic mice overexpressing human FLAG-PAD2 downstream of the MMTV-LTR promoter develop spontaneous neoplastic skin lesions. Molecular and histopathologic analyses of the resulting lesions find that they contain increased levels of markers for invasion, inflammation, and epithelial-to-mesenchymal transition (EMT) and that a subset of the lesions progress to invasive squamous cell carcinoma (SCC). We then stably overexpressed FLAG-PAD2 in the human SCC cell line, A431, and found that the PAD2-overexpressing cells were more tumorigenic in vitro and also contained elevated levels of markers for inflammation and EMT. Collectively, these studies provide the first genetic evidence that PAD2 functions as an oncogene and suggest that PAD2 may promote tumor progression by enhancing inflammation within the tumor microenvironment. Cancer Res; 74(21); 6306–17. ©2014 AACR.
Data from CD38-Expressing Myeloid-Derived Suppressor Cells Promote Tumor Growth in a Murine Model of Esophageal Cancer
Authors: Karakasheva Tatiana A. , Waldron Todd J. , Eruslanov Evgeniy , Kim Sang-Bae , Lee Ju-Seog , O'Brien Shaun , Hicks Philip D. , Basu Devraj , Singhal Sunil , Malavasi Fabio , Rustgi Anil K.
Published: March 2024

Abstract
Myeloid-derived suppressor cells (MDSC) are an immunosuppressive population of immature myeloid cells found in advanced-stage cancer patients and mouse tumor models. Production of inducible nitric oxide synthase (iNOS) and arginase, as well as other suppressive mechanisms, allows MDSCs to suppress T-cell–mediated tumor clearance and foster tumor progression. Using an unbiased global gene expression approach in conditional p120-catenin knockout mice (L2-cre;p120ctnf/f), a model of oral–esophageal cancer, we have identified CD38 as playing a vital role in MDSC biology, previously unknown. CD38 belongs to the ADP-ribosyl cyclase family and possesses both ectoenzyme and receptor functions. It has been described to function in lymphoid and early myeloid cell differentiation, cell activation, and neutrophil chemotaxis. We find that CD38 expression in MDSCs is evident in other mouse tumor models of esophageal carcinogenesis, and CD38high MDSCs are more immature than MDSCs lacking CD38 expression, suggesting a potential role for CD38 in the maturation halt found in MDSC populations. CD38high MDSCs also possess a greater capacity to suppress activated T cells, and promote tumor growth to a greater degree than CD38low MDSCs, likely as a result of increased iNOS production. In addition, we have identified novel tumor–derived factors, specifically IL6, IGFBP3, and CXCL16, which induce CD38 expression by MDSCs ex vivo. Finally, we have detected an expansion of CD38+ MDSCs in peripheral blood of advanced-stage cancer patients and validated targeting CD38 in vivo as a novel approach to cancer therapy. Cancer Res; 75(19); 4074–85. ©2015 AACR.
Data from Naturally Occurring Mutations in the MPS1 Gene Predispose Cells to Kinase Inhibitor Drug Resistance
Authors: Gurden Mark D. , Westwood Isaac M. , Faisal Amir , Naud Sébastien , Cheung Kwai-Ming J. , McAndrew Craig , Wood Amy , Schmitt Jessica , Boxall Kathy , Mak Grace , Workman Paul , Burke Rosemary , Hoelder Swen , Blagg Julian , Van Montfort Rob L.M. , Linardopoulos Spiros
Published: March 2024

Abstract
Acquired resistance to therapy is perhaps the greatest challenge to effective clinical management of cancer. With several inhibitors of the mitotic checkpoint kinase MPS1 in preclinical development, we sought to investigate how resistance against these inhibitors may arise so that mitigation or bypass strategies could be addressed as early as possible. Toward this end, we modeled acquired resistance to the MPS1 inhibitors AZ3146, NMS-P715, and CCT251455, identifying five point mutations in the kinase domain of MPS1 that confer resistance against multiple inhibitors. Structural studies showed how the MPS1 mutants conferred resistance by causing steric hindrance to inhibitor binding. Notably, we show that these mutations occur in nontreated cancer cell lines and primary tumor specimens, and that they also preexist in normal lymphoblast and breast tissues. In a parallel piece of work, we also show that the EGFR p.T790M mutation, the most common mutation conferring resistance to the EGFR inhibitor gefitinib, also preexists in cancer cells and normal tissue. Our results therefore suggest that mutations conferring resistance to targeted therapy occur naturally in normal and malignant cells and these mutations do not arise as a result of the increased mutagenic plasticity of cancer cells. Cancer Res; 75(16); 3340–54. ©2015 AACR.
Data from Tristetraprolin Limits Inflammatory Cytokine Production in Tumor-Associated Macrophages in an mRNA Decay–Independent Manner
Authors: Kratochvill Franz , Gratz Nina , Qualls Joseph E. , Van De Velde Lee-Ann , Chi Hongbo , Kovarik Pavel , Murray Peter J.
Published: March 2024

Abstract
Tristetraprolin (TTP) is an inducible zinc finger AU-rich RNA-binding protein essential for enforcing degradation of mRNAs encoding inflammatory chemokines and cytokines. Most studies on TTP center on the connection between mRNA half-life and inflammatory output, because loss of TTP amplifies inflammation by increasing the stability of AU-rich mRNAs. Here, we focused on how TTP controls cytokine and chemokine production in the nonresolving inflammation of cancer using tissue-specific approaches. In contrast with model in vitro macrophage systems, we found constitutive TTP expression in late-stage tumor-associated macrophages (TAM). However, TTP's effects on AU-rich mRNA stability were negligible and limited by constitutive p38α MAPK activity, which was the main driver of proinflammatory cytokine production in TAMs at the posttranscriptional level. Instead, elimination of TTP caused excessive protein production of inflammatory mediators, suggesting TTP-dependent translational suppression of AU-rich mRNAs. Manipulation of the p38α–TTP axis in macrophages has significant effects on the growth of tumors and therefore represents a means to manipulate inflammation in the tumor microenvironment. Cancer Res; 75(15); 3054–64. ©2015 AACR.
Data from Therapeutically Targetable ALK Mutations in Leukemia
Authors: Maxson Julia E. , Davare Monika A. , Luty Samuel B. , Eide Christopher A. , Chang Bill H. , Loriaux Marc M. , Tognon Cristina E. , Bottomly Daniel , Wilmot Beth , McWeeney Shannon K. , Druker Brian J. , Tyner Jeffrey W.
Published: March 2024

Abstract
Genome sequencing is revealing a vast mutational landscape in leukemia, offering new opportunities for treatment with targeted therapy. Here, we identify two patients with acute myelogenous leukemia and B-cell acute lymphoblastic leukemia whose tumors harbor point mutations in the ALK kinase. The mutations reside in the extracellular domain of ALK and are potently transforming in cytokine-independent cellular assays and primary mouse bone marrow colony formation studies. Strikingly, both mutations conferred sensitivity to ALK kinase inhibitors, including the FDA-approved drug crizotinib. On the basis of our results, we propose that tumors harboring ALK mutations may be therapeutically tractable for personalized treatment of certain aggressive leukemias with ALK inhibitors. Cancer Res; 75(11); 2146–50. ©2015 AACR.
Data from Implication of a Chromosome 15q15.2 Locus in Regulating UBR1 and Predisposing Smokers to MGMT Methylation in Lung
Authors: Leng Shuguang , Wu Guodong , Collins Leonard B. , Thomas Cynthia L. , Tellez Carmen S. , Jauregui Andrew R. , Picchi Maria A. , Zhang Xiequn , Juri Daniel E. , Desai Dhimant , Amin Shantu G. , Crowell Richard E. , Stidley Christine A. , Liu Yushi , Swenberg James A. , Lin Yong , Wathelet Marc G. , Gilliland Frank D. , Belinsky Steven A.
Published: March 2024

Abstract
O6-Methylguanine-DNA methyltransferase (MGMT) is a DNA repair enzyme that protects cells from carcinogenic effects of alkylating agents; however, MGMT is silenced by promoter hypermethylation during carcinogenesis. A single-nucleotide polymorphism (SNP) in an enhancer in the MGMT promoter was previously identified to be highly significantly associated with risk for MGMT methylation in lung cancer and sputum from smokers. To further genetic investigations, a genome-wide association and replication study was conducted in two smoker cohorts to identify novel loci for MGMT methylation in sputum that were independent of the MGMT enhancer polymorphism. Two novel trans-acting loci (15q15.2 and 17q24.3) that were identified acted together with the enhancer SNP to empower risk prediction for MGMT methylation. We found that the predisposition to MGMT methylation arising from the 15q15.2 locus involved regulation of the ubiquitin protein ligase E3 component UBR1. UBR1 attenuation reduced turnover of MGMT protein and increased repair of O6-methylguanine in nitrosomethylurea-treated human bronchial epithelial cells, while also reducing MGMT promoter activity and abolishing MGMT induction. Overall, our results substantiate reduced gene transcription as a major mechanism for predisposition to MGMT methylation in the lungs of smokers, and support the importance of UBR1 in regulating MGMT homeostasis and DNA repair of alkylated DNA adducts in cells. Cancer Res; 75(15); 3108–17. ©2015 AACR.
Data from Targeting Pancreatic Cancer Metastasis by Inhibition of Vav1, a Driver of Tumor Cell Invasion
Authors: Razidlo Gina L. , Magnine Christopher , Sletten Arthur C. , Hurley Rachel M. , Almada Luciana L. , Fernandez-Zapico Martin E. , Ji Baoan , McNiven Mark A.
Published: March 2024

Abstract
Pancreatic cancer, one of the most lethal forms of human cancer, is largely resistant to many conventional chemotherapeutic agents. Although many therapeutic approaches focus on tumor growth, metastasis is a primary factor contributing to lethality. Therefore, novel therapies to target metastatic invasion could prevent tumor spread and recurrence resulting from local and distant metastasis. The protein Vav1 is aberrantly expressed in more than half of pancreatic cancers. Its expression promotes activation of Rac and Cdc42 and leads to enhanced invasion and migration, as well as increased tumor cell survival and proliferation, suggesting that Vav1 could be a potent therapeutic target for pancreatic cancer. The purine analogue azathioprine, well known for its function as an anti-inflammatory compound, was recently shown to function by inhibiting Vav1 signaling in immune cells. We therefore hypothesized that azathioprine could also inhibit Vav1 in pancreatic tumor cells to reduce its proinvasive functions. Indeed, we have found that treatment of cultured pancreatic tumor cells with azathioprine inhibited Vav1-dependent invasive cell migration and matrix degradation, through inhibition of Rac and Cdc42 signaling. Furthermore, azathioprine treatment decreased metastasis in both xenograft and genetic mouse models of pancreatic cancer. Strikingly, metastasis was dramatically reduced in Vav1-expressing tumors arising from p48Cre/+, KrasG12D/+, p53F/+ mice. These inhibitory effects were mediated through Vav1, as Vav1-negative cell lines and tumors were largely resistant to azathioprine treatment. These findings demonstrate that azathioprine and related compounds could be potent antimetastatic agents for Vav1-positive pancreatic tumors. Cancer Res; 75(14); 2907–15. ©2015 AACR.
Data from miR-25 Modulates Invasiveness and Dissemination of Human Prostate Cancer Cells via Regulation of αv- and α6-Integrin Expression
Authors: Zoni E. , van der Horst G. , van de Merbel A.F. , Chen L. , Rane J.K. , Pelger R.C.M. , Collins A.T. , Visakorpi T. , Snaar-Jagalska B.E. , Maitland N.J. , van der Pluijm G.
Published: March 2024

Abstract
Altered microRNA (miRNA; miR) expression is associated with tumor formation and progression of various solid cancers. A major challenge in miRNA expression profiling of bulk tumors is represented by the heterogeneity of the subpopulations of cells that constitute the organ, as well as the tumor tissue. Here, we analyzed the expression of miRNAs in a subpopulation of epithelial stem/progenitor-like cells in human prostate cancer [prostate cancer stem cell (PCSC)] and compared their expression profile to more differentiated cancer cells. In both cell lines and clinical prostate cancer specimens, we identified that miR-25 expression in PCSCs was low/absent and steadily increased during their differentiation into cells with a luminal epithelial phenotype. Functional studies revealed that overexpression of miR-25 in prostate cancer cell lines and selected subpopulation of highly metastatic and tumorigenic cells (ALDHhigh) strongly affected the invasive cytoskeleton, causing reduced migration in vitro and metastasis via attenuation of extravasation in vivo. Here, we show, for the first time, that miR-25 can act as a tumor suppressor in highly metastatic PCSCs by direct functional interaction with the 3′-untranslated regions of proinvasive αv- and α6-integrins. Taken together, our observations suggest that miR-25 is a key regulator of invasiveness in human prostate cancer through its direct interactions with αv- and α6-integrin expression. Cancer Res; 75(11); 2326–36. ©2015 AACR.
Data from Tumor-Induced Pressure in the Bone Microenvironment Causes Osteocytes to Promote the Growth of Prostate Cancer Bone Metastases
Authors: Sottnik Joseph L. , Dai Jinlu , Zhang Honglai , Campbell Brittany , Keller Evan T.
Published: March 2024

Abstract
Cross-talk between tumor cells and their microenvironment is critical for malignant progression. Cross-talk mediators, including soluble factors and direct cell contact, have been identified, but roles for the interaction of physical forces between tumor cells and the bone microenvironment have not been described. Here, we report preclinical evidence that tumor-generated pressure acts to modify the bone microenvironment to promote the growth of prostate cancer bone metastases. Tumors growing in mouse tibiae increased intraosseous pressure. Application of pressure to osteocytes, the main mechanotransducing cells in bone, induced prostate cancer growth and invasion. Mechanistic investigations revealed that this process was mediated in part by upregulation of CCL5 and matrix metalloproteinases in osteocytes. Our results defined the critical contribution of physical forces to tumor cell growth in the tumor microenvironment, and they identified osteocytes as a critical mediator in the bone metastatic niche. Cancer Res; 75(11); 2151–8. ©2015 AACR.
Data from Drug Redeployment to Kill Leukemia and Lymphoma Cells by Disrupting SCD1-Mediated Synthesis of Monounsaturated Fatty Acids
Authors: Southam Andrew D. , Khanim Farhat L. , Hayden Rachel E. , Constantinou Julia K. , Koczula Katarzyna M. , Michell Robert H. , Viant Mark R. , Drayson Mark T. , Bunce Chris M.
Published: March 2024

Abstract
The redeployed drug combination of bezafibrate and medroxyprogesterone acetate (designated BaP) has potent in vivo anticancer activity in acute myelogenous leukemia (AML) and endemic Burkitt lymphoma (eBL) patients; however, its mechanism-of-action is unclear. Given that elevated fatty acid biosynthesis is a hallmark of many cancers and that these drugs can affect lipid metabolism, we hypothesized that BaP exerts anticancer effects by disrupting lipogenesis. We applied mass spectrometry–based lipidomics and gene and protein expression measurements of key lipogenic enzymes [acetyl CoA carboxylase 1 (ACC1), fatty acid synthase (FASN), and stearoyl CoA desaturase 1 (SCD1)] to AML and eBL cell lines treated with BaP. BaP treatment decreased fatty acid and phospholipid biosynthesis from 13C D-glucose. The proportion of phospholipid species with saturated and monounsaturated acyl chains was also decreased after treatment, whereas those with polyunsaturated chains increased. BaP decreased SCD1 protein levels in each cell line (0.46- to 0.62-fold; P < 0.023) and decreased FASN protein levels across all cell lines (0.87-fold decrease; P = 1.7 × 10−4). Changes to ACC1 protein levels were mostly insignificant. Supplementation with the SCD1 enzymatic product, oleate, rescued AML and e-BL cells from BaP cell killing and decreased levels of BaP-induced reactive oxygen species, whereas supplementation with the SCD1 substrate (and FASN product), palmitate, did not rescue cells. In conclusion, these data suggest that the critical anticancer actions of BaP are decreases in SCD1 levels and monounsaturated fatty acid synthesis. To our knowledge, this is the first time that clinically available antileukemic and antilymphoma drugs targeting SCD1 have been reported. Cancer Res; 75(12); 2530–40. ©2015 AACR.
Data from Akt Kinase-Interacting Protein 1 Signals through CREB to Drive Diffuse Malignant Mesothelioma
Authors: Yamada Tadaaki , Amann Joseph M. , Fukuda Koji , Takeuchi Shinji , Fujita Naoya , Uehara Hisanori , Iwakiri Shotaro , Itoi Kazumi , Shilo Konstantin , Yano Seiji , Carbone David P.
Published: March 2024

Abstract
Diffuse malignant mesothelioma (DMM) is a tumor of serosal membranes with propensity for progressive local disease. Because current treatment options are largely ineffective, novel therapeutic strategies based on molecular mechanisms and the disease characteristics are needed to improve the outcomes of patients with this disease. Akt kinase interacting protein 1 (Aki1; Freud-1/CC2D1A) is a scaffold protein for the PI3K–PDK1–Akt signaling module that helps determine receptor signal selectivity for EGFR. Aki1 has been suggested as a therapeutic target, but its potential has yet to be evaluated in a tumor setting. Here, we report evidence supporting its definition as a therapeutic target in DMM. In cell-based assays, Aki1 silencing decreased cell viability and caused cell-cycle arrest of multiple DMM cell lines via effects on the PKA–CREB1 signaling pathway. Blocking CREB activity phenocopied Aki1 silencing. Clinically, Aki1 was expressed in most human DMM specimens where its expression correlated with phosphorylated CREB1. Notably, Aki1 siRNA potently blocked tumor growth in an orthotopic implantation model of DMM when administered directly into the pleural cavity of tumor-bearing mice. Our findings suggest an important role for the Aki1–CREB axis in DMM pathogenesis and provide a preclinical rationale to target Aki1 by intrathoracic therapy in locally advanced tumors. Cancer Res; 75(19); 4188–97. ©2015 AACR.
Data from SOCS2 Controls Proliferation and Stemness of Hematopoietic Cells under Stress Conditions and Its Deregulation Marks Unfavorable Acute Leukemias
Authors: Vitali Caterina , Bassani Claudia , Chiodoni Claudia , Fellini Elisa , Guarnotta Carla , Miotti Silvia , Sangaletti Sabina , Fuligni Fabio , De Cecco Loris , Piccaluga Pier P. , Colombo Mario P. , Tripodo Claudio
Published: March 2024

Abstract
Hematopoietic stem cells (HSC) promptly adapt hematopoiesis to stress conditions, such as infection and cancer, replenishing bone marrow–derived circulating populations, while preserving the stem cell reservoir. SOCS2, a feedback inhibitor of JAK–STAT pathways, is expressed in most primitive HSC and is upregulated in response to STAT5-inducing cytokines. We demonstrate that Socs2 deficiency unleashes HSC proliferation in vitro, sustaining STAT5 phosphorylation in response to IL3, thrombopoietin, and GM-CSF. In vivo, SOCS2 deficiency leads to unrestricted myelopoietic response to 5-fluorouracil (5-FU) and, in turn, induces exhaustion of long-term HSC function along serial bone marrow transplantations. The emerging role of SOCS2 in HSC under stress conditions prompted the investigation of malignant hematopoiesis. High levels of SOCS2 characterize unfavorable subsets of acute myeloid and lymphoblastic leukemias, such as those with MLL and BCR/ABL abnormalities, and correlate with the enrichment of genes belonging to hematopoietic and leukemic stemness signatures. In this setting, SOCS2 and its correlated genes are part of regulatory networks fronted by IKZF1/Ikaros and MEF2C, two transcriptional regulators involved in normal and leukemic hematopoiesis that have never been linked to SOCS2. Accordingly, a comparison of murine wt and Socs2−/− HSC gene expression in response to 5-FU revealed a significant overlap with the molecular programs that correlate with SOCS2 expression in leukemias, particularly with the oncogenic pathways and with the IKZF1/Ikaros and MEF2C-predicted targets. Lentiviral gene transduction of murine hematopoietic precursors with Mef2c, but not with Ikzf1, induces Socs2 upregulation, unveiling a direct control exerted by Mef2c over Socs2 expression. Cancer Res; 75(11); 2387–99. ©2015 AACR.