bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from In vivo Imaging of Cutaneous T-Cell Lymphoma Migration to the Skin
Authors: Hoeller Christoph , Richardson Stephen K. , Ng Lai Guan , Valero Teresa , Wysocka Maria , Rook Alain H. , Weninger Wolfgang
Published: March 2023

Abstract
Cutaneous T-cell lymphoma (CTCL) is characterized by the accumulation of malignant CD4+ T cells in the skin. Although the expression of adhesion molecules and chemokine receptors on CTCL cells has been studied extensively on ex vivo isolated cells, very little is known about the dynamics and mechanisms of CTCL trafficking in vivo. However, detailed knowledge of the molecular cues mediating CTCL migration may be used to interfere with their homing to the skin. We made use of real-time intravital epifluorescence video and two-photon microscopy to visualize malignant T cells from Sezary syndrome (SS), a leukemic variant of CTCL, in dermal microvessels in mouse ear skin. We found that SS cells rolled along dermal venules in a P-selectin– and E-selectin–dependent manner at ratios similar to CD4+ memory T cells from normal donors. We furthermore show that the chemokine CCL17/TARC, but not CCL27/CTACK, was sufficient to induce the arrest of SS cells in the microvasculature. However, a combination of both chemokines was required to induce extravasation of SS cells. Together, our experiments delineate the molecular adhesion cascade operant in SS cell homing to the skin in vivo. [Cancer Res 2009;69(7):2704–8]
Data from A High Throughput, Whole Cell Screen for Small Molecule Inhibitors of the Mitotic Spindle Checkpoint Identifies OM137, a Novel Aurora Kinase Inhibitor
Authors: DeMoe Joanna H. , Santaguida Stefano , Daum John R. , Musacchio Andrea , Gorbsky Gary J.
Published: March 2023

Abstract
In mitosis, the kinetochores of chromosomes that lack full microtubule attachments and/or mechanical tension activate a signaling pathway called the mitotic spindle checkpoint that blocks progression into anaphase and prevents premature segregation of the chromatids until chromosomes become aligned at the metaphase plate. The spindle checkpoint is responsible for arresting cells in mitosis in response to chemotherapeutic spindle poisons such as paclitaxel or vinblastine. Some cancer cells show a weakened checkpoint signaling system that may contribute to chromosome instability in tumors. Because complete absence of the spindle checkpoint leads to catastrophic cell division, we reasoned that drugs targeting the checkpoint might provide a therapeutic window in which the checkpoint would be eliminated in cancer cells but sufficiently preserved in normal cells. We developed an assay to identify lead compounds that inhibit the spindle checkpoint. Most cells respond to microtubule drugs by activating the spindle checkpoint and arresting in mitosis with a rounded morphology. Our assay depended on the ability of checkpoint inhibitor compounds to drive mitotic exit and cause cells to flatten onto the substrate in the continuous presence of microtubule drugs. In this study, we characterize one of the compounds, OM137, as an inhibitor of Aurora kinases. We find that this compound is growth inhibitory to cultured cells when applied at high concentration and potentiates the growth inhibitory effects of subnanomolar concentrations of paclitaxel. [Cancer Res 2009;69(4):1509–16]
Data from Immune Rejection of Mouse Tumors Expressing Mutated Self
Authors: Duan Fei , Lin Yun , Liu Cailian , Engelhorn Manuel E. , Cohen Adam D. , Curran Michael , Sakaguchi Shimon , Merghoub Taha , Terzulli Stephanie , Wolchok Jedd D. , Houghton Alan N.
Published: March 2023

Abstract
How the immune system recognizes and responds to mutations expressed by cancer cells is a critical issue for cancer immunology. Mutated self-polypeptides are particularly strong tumor-specific rejection antigens for natural tumor immunity, but we know remarkably little about T-cell responses to mutated self during tumor growth in vivo, including levels of response, kinetics, and correlates that predict tumor rejection. To address these questions, a mutated self-antigen, designated tyrosinase-related protein 1 (Tyrp1)-WM, derived from Tyrp1 was expressed in the poorly immunogenic, spontaneously arising B16 melanoma and the immunogenic, chemically induced LiHa fibrosarcoma. Syngeneic mice challenged with LiHa fibrosarcoma cells expressing Tyrp1-WM, but not native Tyrp1, induced specific CD8+ and CD4+ T-cell responses against defined mutated epitopes in tumor-draining lymph nodes and in tumors. Subsequently, specific CD8+ T-cell responses contracted as a minority of tumors progressed. B16 melanomas expressing Tyrp1-WM induced minimal T-cell responses, and no tumor immunity was detected. Treatment with an agonist monoclonal antibody against glucocorticoid-induced tumor necrosis factor receptor family–related gene (GITR) increased the level of CD8+ T cells recognizing a peptide derived from the Tyrp1-WM sequence and the proportion of mice rejecting tumors. These results show that B16 tumors expressing mutations that generate strongly immunogenic epitopes naturally induce T-cell responses, which are insufficient to reject tumors. Immune modulation, such as inducing GITR signaling, is required to enhance CD8+ T-cell responses to specific mutations and to lead to tumor rejection. [Cancer Res 2009;69(8):3545–53]
Data from Fibroblast Growth Factor Receptor 1–Transformed Mammary Epithelial Cells Are Dependent on RSK Activity for Growth and Survival
Authors: Xian Wa , Pappas Leontios , Pandya Darshan , Selfors Laura M. , Derksen Patrick W. , de Bruin Michiel , Gray Nathanael S. , Jonkers Jos , Rosen Jeffrey M. , Brugge Joan S.
Published: March 2023

Abstract
Fibroblast growth factor receptor 1 (FGFR1) is frequently amplified and highly expressed in lobular carcinomas of the breast. In this report, we evaluated the biological activity of FGFR1 in a wide range of in vitro assays. Conditional activation of FGFR1 in the nontransformed MCF10A human mammary cell line, MCF10A, resulted in cellular transformation marked by epidermal growth factor–independent cell growth, anchorage-independent cell proliferation and survival, loss of cell polarity, and epithelial-to-mesenchymal transition. Interestingly, small-molecule or small interfering RNA inhibition of ribosomal S6 kinase (RSK) activity induced death of the FGFR1-transformed cells, but not of the parental MCF10A cell line. The dependence of FGFR1-transformed cells on RSK activity was further confirmed in cell lines derived from mouse and human lobular carcinomas that possess high FGFR1 activity. Taken together, these results show the transforming activity of FGFR1 in mammary epithelial cells and identify RSK as a critical component of FGFR1 signaling in lobular carcinomas, thus implicating RSK as a candidate therapeutic target in FGFR1-expressing tumors. [Cancer Res 2009;69(6):2244–51]
Data from Real-time Study of E-Cadherin and Membrane Dynamics in Living Animals: Implications for Disease Modeling and Drug Development
Authors: Serrels Alan , Timpson Paul , Canel Marta , Schwarz Juliane P. , Carragher Neil O. , Frame Margaret C. , Brunton Valerie G. , Anderson Kurt I.
Published: March 2023

Abstract
The ability of tumor cells to invade and metastasize requires deregulation of interactions with adjacent cells and the extracellular matrix. A major challenge of cancer biology is to observe the dynamics of the proteins involved in this process in their functional and physiologic context. Here, for the first time, we have used photobleaching and photoactivation to compare the mobility of cell adhesion and plasma membrane probes in vitro and in tumors grown in mice (in vivo). We find differences between in vitro and in vivo recovery dynamics of two key molecules, the tumor suppressor E-cadherin and the membrane-targeting sequence of H-Ras. Our data show that E-cadherin dynamics are significantly faster in vivo compared with cultured cells, that the ratio of E-cadherin stabilized in cell-cell junctions is significantly higher in vivo, and that E-cadherin mobility correlates with cell migration. Moreover, quantitative imaging has allowed us to assess the effects of therapeutic intervention on E-cadherin dynamics using dasatinib, a clinically approved Src inhibitor, and show clear differences in the efficacy of drug treatment in vivo. Our results show for the first time the utility of photobleaching and photoactivation in the analysis of dynamic biomarkers in living animals. Furthermore, this work highlights critical differences in molecular dynamics in vitro and in vivo, which have important implications for the use of cultured disease models as surrogates for living tissue. [Cancer Res 2009;69(7):2714–9]
Data from Coordination of Intratumoral Immune Reaction and Human Colorectal Cancer Recurrence
Authors: Camus Matthieu , Tosolini Marie , Mlecnik Bernhard , Pagès Franck , Kirilovsky Amos , Berger Anne , Costes Anne , Bindea Gabriela , Charoentong Pornpimol , Bruneval Patrick , Trajanoski Zlatko , Fridman Wolf-Herman , Galon Jérôme
Published: March 2023

Abstract
A role for the immune system in controlling the progression of solid tumors has been established in several mouse models. However, the effect of immune responses and tumor escape on patient prognosis in the context of human cancer is poorly understood. Here, we investigate the cellular and molecular parameters that could describe in situ immune responses in human colorectal cancer according to clinical parameters of metastatic lymph node or distant organ invasion (META− or META+ patients). Primary tumor samples of colorectal carcinoma were analyzed by integrating large-scale phenotypic (flow cytometry, 39 patients) and gene expression (real time reverse transcription-PCR, 103 patients) data sets related to immune and protumoral processes. In META− colorectal cancer primary tumors with high densities of T cells, we observed significant positive correlations between markers of innate immune cells [tumor-associated macrophages, dendritic cells, natural killer (NK) cells, and NKT cells] and markers of early-activated T cells. Significant correlations were also observed between markers of cytotoxic and effector memory T-cell subpopulations. These correlation profiles were absent in tumors with low T-cell infiltrates and were altered in META+ tumors with high T-cell infiltrates. We show that the coexpression of genes mediating cytotoxicity (GNLY) and Th1 adaptive immune responses (IRF1) accurately predicted patient survival independently of the metastatic status. High intratumoral mRNA expression of the proangiogenic mediator vascular endothelial growth factor was associated with significantly reduced survival rates in patients expressing high mRNA levels of GNLY. Investigation of the colorectal cancer primary tumor microenvironment allowed us to uncover the association of favorable outcomes with efficient coordination of the intratumoral immune response. [Cancer Res 2009;69(6):2685–93]
Data from Human ZNF312b Promotes the Progression of Gastric Cancer by Transcriptional Activation of the K-ras Gene
Authors: Song In-Sung , Oh Nang Su , Kim Hyun-Taek , Ha Ga-Hee , Jeong So-Young , Kim Jeong-Min , Kim Dong-Il , Yoo Hyang-Sook , Kim Cheol-Hee , Kim Nam-Soon
Published: March 2023

Abstract
Gastric cancer ranks second among the most common causes of cancer deaths worldwide. Recent studies reported target molecules that are candidates for new therapeutic interventions; however, their molecular mechanism has not been clearly defined. In this study, we found that ZNF312b plays a role in tumor progression and metastasis in gastric cancer via transcriptional activation of the K-ras oncogene. ZNF312b seems to be specifically overexpressed in gastric cancer tissues and cell lines. The overexpression of ZNF312b induces cancer-like phenotypes, including accelerated proliferation and increased tumor masses in nude mice, which are completely reversed by its knockdown in gastric cancer cell lines, implying direct involvement in gastric tumor progression. From analyses using deletion mutants of ZNF312b and K-ras promoter-driven luciferase reporters, we found that it translocates into the nucleus via the proline-rich domain of its COOH terminus to activate transcription of the K-ras gene, resulting in an enhancement of the extracellular signal-regulated kinase signaling pathway that governs cell proliferation. Taken together, these results suggest that ZNF312b contributes to the promotion of gastric cancer by triggering K-ras oncogene expression. The current study is the first to report that ZNF312b, a novel transcription factor, was associated with tumorigenicity of gastric cancer. This might be a valuable target that could provide new insight into the development of new therapeutic modalities for patients with gastric cancer. [Cancer Res 2009;69(7):3131–9]
Data from CXC Receptor-1 Silencing Inhibits Androgen-Independent Prostate Cancer
Authors: Shamaladevi Nagarajarao , Lyn Dominic A. , Escudero Diogo O. , Lokeshwar Bal L.
Published: March 2023

Abstract
The CXC receptor-1 (CXCR1) is a coreceptor for interleukin-8 (IL-8) and is expressed on both normal and tumor cells. The function of CXCR1 in prostate cancer was investigated by silencing its expression, using RNA interference. We established stable cell colonies of PC-3 cells, depleted of CXCR1, using lentiviral plasmids (pLK0.1puro) generating small hairpin RNA (shRNA) against CXCR1 mRNA. Stable shRNA transfectants (PLK1–PLK5) that express significantly reduced CXCR1 mRNA (≥90% down) and protein (≥43% down) or vector-only transfectants (PC-3V) were characterized. PLK cells showed reduced cell proliferation (down, ≥66%), due to cell cycle arrest at G1-S phase, decreases in Cyclin D1, CDK4, phosphorylated Rb, and extracellular signal-regulated kinase 1/2 levels compared with those in PC-3V cells. CXCR1 depletion lead to increases in spontaneous apoptosis by mitochondria-mediated intrinsic mechanism and increases in proapoptotic proteins (BAD, 40%; BAX, 12%), but decreases in antiapoptotic proteins (BCL2, down 38%; BCLxL, 20%). PLK2 cells grew as slow-growing tumors (decrease of 54%), compared with that of PC3V tumors in athymic mice. Ex vivo analyses of PLK2 tumor tissues showed reduced expression of Cyclin D1 and vascular endothelial growth factor, and increased apoptosis activity. Other IL-8–expressing prostate cancer cell lines also exhibited similar phenotypes when CXCR1 was depleted by CXCR1 shRNA transfection. In contrast to these cells, CXCR1 depletion had little effect on IL-8 ligand–deficient LNCaP cells. RNA interference rescue using mutated CXCR1 plasmids reversed the silencing effect of PLK2, thus demonstrating the specificity of phenotypic alteration by CXCR1 shRNA. These studies establish that CXCR1 promotes IL-8–mediated tumor growth. [Cancer Res 2009;69(21):8265–74]
Data from Small Molecule XIAP Inhibitors Enhance TRAIL-Induced Apoptosis and Antitumor Activity in Preclinical Models of Pancreatic Carcinoma
Authors: Vogler Meike , Walczak Henning , Stadel Dominic , Haas Tobias L. , Genze Felicitas , Jovanovic Marjana , Bhanot Umesh , Hasel Cornelia , Möller Peter , Gschwend Jürgen E. , Simmet Thomas , Debatin Klaus-Michael , Fulda Simone
Published: March 2023

Abstract
Evasion of apoptosis is a characteristic feature of pancreatic cancer, a prototypic cancer that is refractory to current treatment approaches. Hence, there is an urgent need to design rational strategies that counter apoptosis resistance. To explore X-linked inhibitor of apoptosis (XIAP) as a therapeutic target in pancreatic cancer, we analyzed the expression of XIAP in pancreatic tumor samples and evaluated the effect of small molecule XIAP inhibitors alone and in combination with tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) against pancreatic carcinoma in vitro and in vivo. Here, we report that XIAP is highly expressed in pancreatic adenocarcinoma samples compared with normal pancreatic ducts. Small molecule XIAP inhibitors synergize with TRAIL to induce apoptosis and to inhibit long-term clonogenic survival of pancreatic carcinoma cells. In contrast, they do not reverse the lack of toxicity of TRAIL on nonmalignant cells in vitro or normal tissues in vivo, pointing to a therapeutic index. Most importantly, XIAP inhibitors cooperate with TRAIL to trigger apoptosis and suppress pancreatic carcinoma growth in vivo in two preclinical models, i.e., the chorioallantoic membrane model and a mouse xenograft model. Parallel immunohistochemical analysis of tumor tissue under therapy reveals that the XIAP inhibitor acts in concert with TRAIL to cause caspase-3 activation and apoptosis. In conclusion, our findings provide, for the first time, evidence in vivo that XIAP inhibitors prime pancreatic carcinoma cells for TRAIL-induced apoptosis and potentiate the antitumor activity of TRAIL against established pancreatic carcinoma. These findings build the rationale for further (pre)clinical development of XIAP inhibitors and TRAIL against pancreatic cancer. [Cancer Res 2009;69(6):2425–34]
Data from Large-Scale Profiling of Archival Lymph Nodes Reveals Pervasive Remodeling of the Follicular Lymphoma Methylome
Authors: Killian J. Keith , Bilke Sven , Davis Sean , Walker Robert L. , Killian M. Scott , Jaeger Erich B. , Chen Yidong , Hipp Jason , Pittaluga Stefania , Raffeld Mark , Cornelison Robert , Smith, William I. , Bibikova Marina , Fan Jian-Bing , Emmert-Buck Michael R. , Jaffe Elaine S. , Meltzer Paul S.
Published: March 2023

Abstract
Emerging technologies allow broad profiling of the cancer genome for differential DNA methylation relative to benign cells. Herein, bisulfite-modified DNA from lymph nodes with either reactive hyperplasia or follicular lymphoma (FL) were analyzed using a commercial C/UpG genotyping assay. Two hundred fifty-nine differentially methylated targets (DMT) distributed among 183 unique genes were identified in FL. Comparison of matched formalin-fixed, paraffin-embedded and frozen surgical pathology replicates showed the complete preservation of the cancer methylome among differently archived tissue specimens. Analysis of the DMT profile is consistent with a pervasive epigenomic remodeling process in FL that affects predominantly nonlymphoid genes. [Cancer Res 2009;69(3):758–64]
Data from DDB1 Targets Chk1 to the Cul4 E3 Ligase Complex in Normal Cycling Cells and in Cells Experiencing Replication Stress
Authors: Leung-Pineda Van , Huh Jiwon , Piwnica-Worms Helen
Published: March 2023

Abstract
The Chk1 protein kinase preserves genome integrity in normal proliferating cells and in cells experiencing replicative and genotoxic stress. Chk1 is currently being targeted in anticancer regimens. Here, we identify damaged DNA-binding protein 1 (DDB1) as a novel Chk1-interacting protein. DDB1 is part of an E3 ligase complex that includes the cullin proteins Cul4A and Cul4B. We report that Cul4A/DDB1 negatively regulates Chk1 stability in vivo. Chk1 associates with Cul4A/DDB1 during an unperturbed cell division cycle and both Chk1 phosphorylation and replication stress enhanced these interactions. Cul4A/DDB1 regulates Chk1 ubiquitination in vivo and Chk1 is directly ubiquitinated in vitro in a Cul4A/DDB1–dependent manner. Furthermore, Chk1 is stabilized in cells deficient for Cul4A/DDB1. This study shows that Chk1 abundance is regulated by the Cul4A/DDB1 ubiquitin ligase during an unperturbed cell division cycle, in response to replicative stress and on heat shock protein 90 inhibition, and that deregulation of the Chk1/Cul4A/DDB1 pathway perturbs the ionizing radiation–induced G2 checkpoint. [Cancer Res 2009;69(6):2630–7]
Data from Role of RUNX3 in Bone Morphogenetic Protein Signaling in Colorectal Cancer
Authors: Lee Cecilia Wei Lin , Ito Kosei , Ito Yoshiaki
Published: March 2023

Abstract
Bone morphogenetic proteins (BMPs), members of the transforming growth factor-β (TGF-β) superfamily, are multifunctional cytokines regulating a broad spectrum of biological functions. Recent studies show the presence of BMP receptor 1a mutations in juvenile polyposis and frequent Smad4 mutations in colon cancer, suggesting that aberrations in BMP signaling play an important role in intestinal cancer pathogenesis. However, the exact molecular mechanisms remain poorly understood. The Runt domain transcription factor RUNX3 is an integral component of signaling pathways mediated by TGF-β and BMPs. RUNX3 is a gastric and colon tumor suppressor, functioning downstream of TGF-β. Recently, we showed the tumor-suppressive effects of RUNX3 by its ability to attenuate β-catenin/T-cell factors (TCFs) transactivation in intestinal tumorigenesis. Here, we explore the molecular basis of the tumor-suppressive function of the BMP pathway through RUNX3 in colorectal carcinogenesis. BMP exerted a growth-suppressive effect in HT-29, a human colorectal cancer cell line. c-Myc oncogene was found to be downregulated by BMP and/or RUNX3. We show that upregulation of RUNX3 by BMP reduces c-Myc expression. Evidence is presented suggesting that RUNX3 downregulates c-Myc expression by two parallel pathways—directly at the transcriptional level and through attenuation of β-catenin/TCFs, downstream of BMPs in colorectal cancer cells. Cancer Res; 70(10); 4243–52. ©2010 AACR.
Data from Pathway Analysis of Breast Cancer Genome-Wide Association Study Highlights Three Pathways and One Canonical Signaling Cascade
Authors: Menashe Idan , Maeder Dennis , Garcia-Closas Montserrat , Figueroa Jonine D. , Bhattacharjee Samsiddhi , Rotunno Melissa , Kraft Peter , Hunter David J. , Chanock Stephen J. , Rosenberg Philip S. , Chatterjee Nilanjan
Published: March 2023

Abstract
Genome-wide association studies (GWAS) focus on relatively few highly significant loci, whereas less attention is given to other genotyped markers. Using pathway analysis to study existing GWAS data may shed light on relevant biological processes and illuminate new candidate genes. We applied a pathway-based approach to the breast cancer GWAS data of the National Cancer Institute (NCI) Cancer Genetic Markers of Susceptibility project that includes 1,145 cases and 1,142 controls. Pathways were retrieved from three databases: KEGG, BioCarta, and NCI Protein Interaction Database. Genes were represented by their most strongly associated SNP, and an enrichment score reflecting the overrepresentation of gene-based association signals in each pathway was calculated by using a weighted Kolmogorov-Smirnov procedure. Finally, hierarchical clustering was used to identify pathways with overlapping genes, and clusters with an excess of association signals were determined by the adaptive rank-truncated product (ARTP) method. A total of 421 pathways containing 3,962 genes was included in our study. Of these, three pathways (syndecan-1–mediated signaling, signaling of hepatocyte growth factor receptor, and growth hormone signaling) were highly enriched with association signals [PES < 0.001, false discovery rate (FDR) = 0.118]. Our clustering analysis revealed that pathways containing key components of the RAS/RAF/mitogen-activated protein kinase canonical signaling cascade were significantly more likely to have an excess of association signals than expected by chance (PARTP = 0.0051, FDR = 0.07). These results suggest that genetic alterations associated with these three pathways and one canonical signaling cascade may contribute to breast cancer susceptibility. Cancer Res; 70(11); 4453–9. ©2010 AACR.
Data from Chromobox Protein Homologue 7 Protein, with Decreased Expression in Human Carcinomas, Positively Regulates E-Cadherin Expression by Interacting with the Histone Deacetylase 2 Protein
Authors: Federico Antonella , Pallante Pierlorenzo , Bianco Mimma , Ferraro Angelo , Esposito Francesco , Monti Maria , Cozzolino Marianna , Keller Simona , Fedele Monica , Leone Vincenza , Troncone Giancarlo , Chiariotti Lorenzo , Pucci Piero , Fusco Alfredo
Published: March 2023

Abstract
Chromobox protein homologue 7 (CBX7) is a chromobox family protein encoding a novel polycomb protein, the expression of which shows a progressive reduction, well related with the malignant grade of the thyroid neoplasias. Indeed, CBX7 protein levels decreased in an increasing percentage of cases going from benign adenomas to papillary, follicular, and anaplastic thyroid carcinomas. To elucidate the function of CBX7 in carcinogenesis, we searched for CBX7 interacting proteins by a proteomic analysis. By this approach, we identified several proteins. Among these proteins, we selected histone deacetylase 2 (HDAC2), which is well known to play a key role in neoplastic cell transformation and down-regulation of E-cadherin expression, the loss of which is a critical event in the epithelial-to-mesenchymal transition. We confirmed by coimmunoprecipitation that CBX7 physically interacts with the HDAC2 protein and is able to inhibit its activity. Then, we showed that both these proteins bind the E-cadherin promoter and that CBX7 up-regulates E-cadherin expression. Consistent with these data, we found a positive statistical correlation between CBX7 and E-cadherin expression in human thyroid carcinomas. Finally, we showed that the expression of CBX7 increases the acetylation status of the histones H3 and H4 on the E-cadherin promoter. Therefore, the ability of CBX7 to positively regulate E-cadherin expression by interacting with HDAC2 and inhibiting its activity on the E-cadherin promoter would account for the correlation between the loss of CBX7 expression and a highly malignant phenotype. [Cancer Res 2009;69(17):7079–87]
Data from Cyclin E Deregulation Impairs Mitotic Progression through Premature Activation of Cdc25C
Authors: Bagheri-Yarmand Rozita , Nanos-Webb Angela , Biernacka Anna , Bui Tuyen , Keyomarsi Khandan
Published: March 2023

Abstract
The cyclin E–cyclin-dependent kinase 2 (CDK2) complex accelerates entry into the S phase of the cell cycle and promotes polyploidy, which may contribute to genomic instability in cancer cells. The effect of low molecular weight isoforms of cyclin E (LMW-E) overexpression on mitotic progression and its link to genomic instability were the focus of this study. Here, we show that full-length cyclin E (EL) and LMW-E overexpression impairs the G2-M transition differently by targeting dual-specificity phosphatase Cdc25C activity. We identify Cdc25C as an interaction partner and substrate for cyclin E/CDK2 kinase. Specifically, the cyclin E/CDK2 complex phosphorylates Cdc25C on Ser214, leading to its premature activation, which coincides with higher cyclin B/CDK1 and Polo-like kinase 1 (PLK1) activities in an S-phase–enriched population that result in faster mitotic entry. Whereas EL overexpression leads to hyperactivation of Cdc25C, cyclin B/CDK1, and PLK1 in a G2-M–enriched population, LMW-E overexpression causes premature inactivation of Cdc25C and PLK1, leading to faster mitotic exit. In addition, LMW-E–overexpressing cells showed a reduction in the mitotic index in the presence of a spindle poison and faster degradation of cyclin B, suggesting an increased rate of mitotic slippage and adaptation to the spindle checkpoint. Lastly, downregulation of Cdc25C inhibits LMW-E–mediated chromosome missegregation, anaphase bridges, and centrosome amplification. These results suggest that the high levels of LMW-E isoforms found in breast cancer may contribute to cellular transformation and genomic instability by impairing mitotic progression involving Cdc25C. Cancer Res; 70(12); 5085–95. ©2010 AACR.
Data from Three-Dimensional Imaging and Quantification of Both Solitary Cells and Metastases in Whole Mouse Liver by Magnetic Resonance Imaging
Authors: Townson Jason L. , Ramadan Soha S. , Simedrea Carmen , Rutt Brian K. , MacDonald Ian C. , Foster Paula J. , Chambers Ann F.
Published: March 2023

Abstract
The metastatic cell population, ranging from solitary cells to actively growing metastases, is heterogeneous and unlikely to respond uniformly to treatment. However, quantification of the entire experimental metastatic cell population in whole organs is complicated by requirements of an imaging modality with the large field of view and high spatial resolution necessary to detect both single cells and metastases in the same organ. Thus, it is difficult to assess differential responses of these distinct metastatic populations to therapy. Here, we develop a magnetic resonance imaging (MRI) technique capable of quantifying the full population of metastatic cells in a secondary organ. B16F1 mouse melanoma cells were labeled with micron-sized iron oxide particles (MPIO) and injected into mouse liver via the mesenteric vein. Livers were removed immediately or at day 9 or 11, following doxorubicin or vehicle control treatment, and imaged using a 3T clinical magnetic resonance scanner and custom-built gradient coil. Both metastases (>200 μm) and MPIO-labeled single cells were detected and quantified from MR images as areas of hyperintensity or hypointensity (signal voids), respectively. We found that 1mg/kg doxorubicin treatment inhibited metastasis growth (n = 11 per group; P = 0.02, t test) but did not decrease the solitary metastatic cell population in the same livers (P > 0.05). Thus, the technique presented here is capable of quickly quantifying the majority of the metastatic cell population, including both growing metastases and solitary cells, in whole liver by MRI and can identify differential responses of growing metastases and solitary cells to therapy. [Cancer Res 2009;69(21):8326–31]
Data from Low-Field Magnetic Resonance Imaging to Visualize Chronic and Cycling Hypoxia in Tumor-Bearing Mice
Authors: Yasui Hironobu , Matsumoto Shingo , Devasahayam Nallathamby , Munasinghe Jeeva P. , Choudhuri Rajani , Saito Keita , Subramanian Sankaran , Mitchell James B. , Krishna Murali C.
Published: March 2023

Abstract
Tumors exhibit fluctuations in blood flow that influence oxygen concentrations and therapeutic resistance. To assist therapeutic planning and improve prognosis, noninvasive dynamic imaging of spatial and temporal variations in oxygen partial pressure (pO2) would be useful. Here, we illustrate the use of pulsed electron paramagnetic resonance imaging (EPRI) as a novel imaging method to directly monitor fluctuations in oxygen concentrations in mouse models. A common resonator platform for both EPRI and magnetic resonance imaging (MRI) provided pO2 maps with anatomic guidance and microvessel density. Oxygen images acquired every 3 minutes for a total of 30 minutes in two different tumor types revealed that fluctuation patterns in pO2 are dependent on tumor size and tumor type. The magnitude of fluctuations in pO2 in SCCVII tumors ranged between 2- to 18-fold, whereas the fluctuations in HT29 xenografts were of lower magnitude. Alternating breathing cycles with air or carbogen (95% O2 plus 5% CO2) distinguished higher and lower sensitivity regions, which responded to carbogen, corresponding to cycling hypoxia and chronic hypoxia, respectively. Immunohistochemical analysis suggests that the fluctuation in pO2 correlated with pericyte density rather than vascular density in the tumor. This EPRI technique, combined with MRI, may offer a powerful clinical tool to noninvasively detect variable oxygenation in tumors. Cancer Res; 70(16); 6427–36. ©2010 AACR.
Data from Hypoxic Conversion of SMAD7 Function from an Inhibitor into a Promoter of Cell Invasion
Authors: Heikkinen Pekka T. , Nummela Marika , Jokilehto Terhi , Grenman Reidar , Kähäri Veli-Matti , Jaakkola Panu M.
Published: March 2023

Abstract
Smad7 is an inhibitor of the transforming growth factor-β–activated signaling pathway. Under well-oxygenated conditions, Smad7 is a potent inhibitor of carcinoma cell invasion. Paradoxically, however, the expression of Smad7 is upregulated across several cancers and may promote cancer progression. Hypoxia, which is frequently met in solid tumors, is an enhancer of carcinoma cell invasion and cancer progression. Here, we report that hypoxia activates the expression of Smad7 in a hypoxia-inducible factor– and von Hippel-Lindau protein–dependent manner. As expected, in normoxia, the forced expression of Smad7 inhibited carcinoma cell invasion. In contrast with the normoxic condition, the inhibitory effect of Smad7 was lost under hypoxia. The block in carcinoma cell invasion by forced expression of Smad7 was released by hypoxia in two invasive carcinoma cell lines. Moreover, the noninvasive HaCaT keratinocytes become invasive upon simultaneous hypoxia and transforming growth factor-β stimulus. The hypoxia-activated invasion was attenuated by inhibiting Smad7 expression by short interfering RNA. Finally, the increased Smad7 expression in human carcinomas correlated with hypoxic gene expression. The data provide evidence that hypoxia could convert Smad7 function from an invasion inhibitor into an activator of invasion. Furthermore, they might shed light as to why increased Smad7 expression is detected in cancers. Cancer Res; 70(14); 5984–93. ©2010 AACR.
Data from DNMT3B7, a Truncated DNMT3B Isoform Expressed in Human Tumors, Disrupts Embryonic Development and Accelerates Lymphomagenesis
Authors: Shah Mrinal Y. , Vasanthakumar Aparna , Barnes Natalie Y. , Figueroa Maria E. , Kamp Anna , Hendrick Christopher , Ostler Kelly R. , Davis Elizabeth M. , Lin Shang , Anastasi John , Le Beau Michelle M. , Moskowitz Ivan P. , Melnick Ari , Pytel Peter , Godley Lucy A.
Published: March 2023

Abstract
Epigenetic changes are among the most common alterations observed in cancer cells, yet the mechanism by which cancer cells acquire and maintain abnormal DNA methylation patterns is not understood. Cancer cells have an altered distribution of DNA methylation and express aberrant DNA methyltransferase 3B transcripts, which encode truncated proteins, some of which lack the COOH-terminal catalytic domain. To test if a truncated DNMT3B isoform disrupts DNA methylation in vivo, we constructed two lines of transgenic mice expressing DNMT3B7, a truncated DNMT3B isoform commonly found in cancer cells. DNMT3B7 transgenic mice exhibit altered embryonic development, including lymphopenia, craniofacial abnormalities, and cardiac defects, similar to Dnmt3b-deficient animals, but rarely develop cancer. However, when DNMT3B7 transgenic mice are bred with Eμ-Myc transgenic mice, which model aggressive B-cell lymphoma, DNMT3B7 expression increases the frequency of mediastinal lymphomas in Eμ-Myc animals. Eμ-Myc/DNMT3B7 mediastinal lymphomas have more chromosomal rearrangements, increased global DNA methylation levels, and more locus-specific perturbations in DNA methylation patterns compared with Eμ-Myc lymphomas. These data represent the first in vivo modeling of cancer-associated DNA methylation changes and suggest that truncated DNMT3B isoforms contribute to the redistribution of DNA methylation characterizing virtually every human tumor. Cancer Res; 70(14); 5840–50. ©2010 AACR.
Data from Down-regulation of c-FLIP Enhances Death of Cancer Cells by Smac Mimetic Compound
Authors: Cheung Herman H. , Mahoney Douglas J. , LaCasse Eric C. , Korneluk Robert G.
Published: March 2023

Abstract
Smac mimetic compounds (SMC) are novel small molecules being developed for cancer therapy. The mechanism of SMC-induced sensitivity in cancer cells depends on autocrine release of tumor necrosis factor α (TNFα); however, potential mechanisms of resistance remain unknown. Here, we investigated the molecular profile and cytotoxic responsiveness of a diverse panel of 51 cancer cell lines to combinations of a dimeric SMC (AEG40730), death ligand TNFα, and tumor necrosis factor-related apoptosis-inducing ligand. Synergy was seen in combination with death receptor agonists in some cells, although single-agent activity was limited to a fewsensitive lines. Unexpectedly, the majority of cell lines resistant to combinations of SMC-AEG40730 and death ligands expressed caspase-8, FADD, RIP1, and ligand receptors necessary for apoptosis execution. Furthermore, TNFα-mediated ubiquitination of RIP1 was repressed by SMC-AEG40730 treatment, leading to the formation of the proapoptosis complex II. However, in resistant cancer cells, SMC-AEG40730 repressed TNFα-mediated c-jun-NH2-kinase activation and the levels of caspase-8 inhibitor c-FLIP were persistently elevated, in contrast to SMC-responsive cancer cells. Importantly, the silencing of c-FLIP restored SMC sensitivity in previously resistant cancer cells by allowing ligand-mediated activation of caspase-8 and caspase-3 to proceed. Together, these results provide mechanistic insight into the action of SMCs, demonstrating that the deciphering of the relevant molecular signature in cancer cells leads to the prediction of cancer cell responsiveness to SMC treatment. Furthermore, a majority of resistant cancer cells were sensitized to SMC-AEG40730 and TNFα by down-regulating c-FLIP, suggesting novel approaches in the use of SMCs and c-FLIP antagonists in treating cancer. [Cancer Res 2009;69(19):7729–38]
Data from Concurrent Suppression of Integrin α5, Radixin, and RhoA Phenocopies the Effects of miR-31 on Metastasis
Authors: Valastyan Scott , Chang Amelia , Benaich Nathan , Reinhardt Ferenc , Weinberg Robert A.
Published: March 2023

Abstract
miR-31 inhibits breast cancer metastasis via the pleiotropic suppression of a cohort of prometastatic target genes that include integrin α5 (ITGA5), radixin (RDX), and RhoA. We previously showed that the concomitant overexpression of ITGA5, RDX, and RhoA was capable of overriding the antimetastatic effects of ectopically expressed miR-31 in vivo. However, these prior studies failed to investigate whether the combined suppression of the endogenous mRNAs encoding these three proteins recapitulated the in vivo consequences of miR-31 expression on metastasis. We show here that short hairpin RNA–mediated concurrent downregulation of ITGA5, RDX, and RhoA is sufficient to phenocopy the full spectrum of described influences of miR-31 on metastasis in vivo, including the effects of this microRNA (miRNA) on local invasion, early post-intravasation events, and metastatic colonization. These findings provide mechanistic insights into the metastatic process and have implications about the importance of pleiotropy for the biological actions of miRNAs. Cancer Res; 70(12); 5147–54. ©2010 AACR.
Data from High Aldehyde Dehydrogenase Activity Identifies Tumor-Initiating and Metastasis-Initiating Cells in Human Prostate Cancer
Authors: van den Hoogen Christel , van der Horst Geertje , Cheung Henry , Buijs Jeroen T. , Lippitt Jenny M. , Guzmán-Ramírez Natalia , Hamdy Freddie C. , Eaton Colby L. , Thalmann George N. , Cecchini Marco G. , Pelger Rob C.M. , van der Pluijm Gabri
Published: March 2023

Abstract
Metastatic progression of advanced prostate cancer is a major clinical problem. Identifying the cell(s) of origin in prostate cancer and its distant metastases may permit the development of more effective treatment and preventive therapies. In this study, aldehyde dehydrogenase (ALDH) activity was used as a basis to isolate and compare subpopulations of primary human prostate cancer cells and cell lines. ALDH-high prostate cancer cells displayed strongly elevated clonogenicity and migratory behavior in vitro. More strikingly, ALDH-high cells readily formed distant metastases with strongly enhanced tumor progression at both orthotopic and metastatic sites in preclinical models. Several ALDH isoforms were expressed in human prostate cancer cells and clinical specimens of primary prostate tumors with matched bone metastases. Our findings suggest that ALDH-based viable cell sorting can be used to identify and characterize tumor-initiating and, more importantly perhaps, metastasis-initiating cells in human prostate cancer. Cancer Res; 70(12); 5163–73. ©2010 AACR.
Data from HERC2 Is an E3 Ligase That Targets BRCA1 for Degradation
Authors: Wu Wenwen , Sato Ko , Koike Ayaka , Nishikawa Hiroyuki , Koizumi Hirotaka , Venkitaraman Ashok R. , Ohta Tomohiko
Published: March 2023

Abstract
The breast cancer suppressor BRCA1 forms a stable heterodimeric E3 ubiquitin ligase with BARD1. Each protein controls the abundance and stability of the other, and loss of the interaction leads to BRCA1 degradation. Here, we show that HERC2, a protein recently implicated in DNA damage repair, targets BARD1-uncoupled BRCA1 for degradation. HERC2 shuttles between the nucleus and the cytoplasm. Its COOH-terminal HECT-containing domain interacts with an NH2-terminal degron domain in BRCA1. HERC2 ubiquitinates BRCA1; this reaction depends on Cys4762 of HERC2, the catalytic ubiquitin binding site, and the degron of BRCA1. The HERC2-BRCA1 interaction is maximal during the S phase of the cell cycle and rapidly diminishes as cells enter G2-M, inversely correlated with the steady-state level of BRCA1. Significantly, HERC2 depletion antagonizes the effects of BARD1 depletion by restoring BRCA1 expression and G2-M checkpoint activity. Conversely, BARD1 protects BRCA1 from HERC2-mediated ubiquitination. Collectively, our findings identify a function for HERC2 in regulating BRCA1 stability in opposition to BARD1. The HERC2 expression in breast epithelial cells and breast carcinomas suggests that this mechanism may play a role in breast carcinogenesis. Cancer Res; 70(15); 6384–92. ©2010 AACR.
Data from Tetraspanin CD151 Regulates Growth of Mammary Epithelial Cells in Three-Dimensional Extracellular Matrix: Implication for Mammary Ductal Carcinoma In situ
Authors: Novitskaya Vera , Romanska Hanna , Dawoud Marwa , Jones J. Louise , Berditchevski Fedor
Published: March 2023

Abstract
Tetraspanin CD151 is associated with laminin-binding integrins (i.e., α3β1, α6β1, and α6β4) and regulates tumor cell migration and invasion. Here, we examined the role of CD151 in proliferation of mammary epithelial cells using in vitro and in vivo models. Depletion of CD151 suppressed growth of HB2 cells, a nontumorigenic breast epithelial cell line, in three-dimensional (3D) extracellular matrices (ECM) and in Matrigel-based xenografts. Whereas the presence of α3β1 (but not α6 integrins) was necessary to support growth of HB2 cells in 3D ECM, the pro-proliferative activity of CD151 did not require direct interaction with integrins. Furthermore, depletion of CD151 potentiated formation of the internal lumen and partial restoration of polarity when HB2 cells were cultured in 3D ECM. This correlated with a decrease in phosphorylation levels of extracellular signal-regulated kinase 1/2 and cAkt in CD151-negative cells and increase in activation of caspase-3. Accordingly, the number of CD151-positive colonies with internal lumen was increased by ∼5-fold when cells were cultured in the presence of MAP/ERK kinase (U0126) and phosphoinositide 3-kinase (LY29004) inhibitors. To establish the physiologic relevance of pro-proliferative and morphogenetic activities of CD151, we analyzed the expression of this tetraspanin in ductal carcinoma in situ (DCIS), which is characterized by neoplastic proliferation of mammary epithelial cells. Strong homogeneous membrane expression of CD151 was found to be associated with a high grade of DCIS (P = 0.004). Taken together, these results strongly suggest that CD151 complexes play a crucial role in the development of hyperproliferative diseases in the mammary gland. Cancer Res; 70(11); 4698–708. ©2010 AACR.
Data from RAS Mutations Affect Tumor Necrosis Factor–Induced Apoptosis in Colon Carcinoma Cells via ERK-Modulatory Negative and Positive Feedback Circuits Along with Non-ERK Pathway Effects
Authors: Kreeger Pamela K. , Mandhana Roli , Alford Shannon K. , Haigis Kevin M. , Lauffenburger Douglas A.
Published: March 2023

Abstract
More than 40% of colon cancers have a mutation in K-RAS or N-RAS, GTPases that operate as central hubs for multiple key signaling pathways within the cell. Utilizing an isogenic panel of colon carcinoma cells with K-RAS or N-RAS variations, we observed differences in tumor necrosis factor-α (TNFα)–induced apoptosis. When the dynamics of phosphorylated ERK response to TNFα were examined, K-RAS mutant cells showed lower activation whereas N-RAS mutant cells exhibited prolonged duration. These divergent trends were partially explained by differential induction of two ERK-modulatory circuits: negative feedback mediated by dual-specificity phosphatase 5 and positive feedback by autocrine transforming growth factor-α. Moreover, in the various RAS mutant colon carcinoma lines, the transforming growth factor-α autocrine loop differentially elicited a further downstream chemokine (CXCL1/CXCL8) autocrine loop, with the two loops having opposite effects on apoptosis. Although the apoptotic responses of the RAS mutant panel to TNFα treatment showed significant dependence on the respective phosphorylated ERK dynamics, successful prediction across the various cell lines required contextual information concerning additional pathways including IKK and p38. A quantitative computational model based on weighted linear combinations of these pathway activities successfully predicted not only the spectrum of cell death responses but also the corresponding chemokine production responses. Our findings indicate that diverse RAS mutations yield differential cell behavioral responses to inflammatory cytokine exposure by means of (a) differential effects on ERK activity via multiple feedback circuit mechanisms, and (b) differential effects on other key signaling pathways contextually modulating ERK-related dependence. [Cancer Res 2009;69(20):8191–9]
Data from Evaluation of MicroRNA Expression Profiles That May Predict Recurrence of Localized Stage I Non–Small Cell Lung Cancer after Surgical Resection
Authors: Patnaik Santosh K. , Kannisto Eric , Knudsen Steen , Yendamuri Sai
Published: March 2023

Abstract
Prognostic markers that can predict the relapse of localized non–small cell lung cancer (NSCLC) have yet to be defined. We surveyed expression profiles of microRNA (miRNA) in stage I NSCLC to identify patterns that might predict recurrence after surgical resection of this common deadly cancer. Small RNAs extracted from formalin-fixed and paraffin-embedded tissues were hybridized to locked nucleic acid probes against 752 human miRNAs (representing 82% of the miRNAs in the miRBase 13.0 database) to obtain expression profiles for 37 cases with recurrence and 40 cases without recurrence (with clinical follow-up for at least 32 months). Differential expression between the two case groups was detected for 49% of the miRNAs (Wilcoxon rank sum test; P < 0.01). The performance of expression profiles at differentiating the two case groups was assessed by leave-one-out and Monte Carlo cross-validations. In leave-one-out cross-validation using support vector machines- or top-scoring gene pair classifier methods, which looked for six- or two-miRNA-based classifiers, the identified miRNA expression pattern predicted recurrence with an accuracy of 70% and 83%, and hazard ratio of 3.6 [95% confidence interval (95% CI), 1.8–7.1] and 9.0 (95% CI, 4.4–18.2), respectively. Mean accuracy in Monte Carlo cross-validation using 1,000 random 60–17 splits was 69% (95% CI, 68–70) and 72% (95% CI, 71–72), respectively. The specific miRNAs mir-200b*, mir-30c-1*, mir-510, mir-630, mir-657, and mir-146b-3p and mir-124*, mir-585, and mir-708, respectively, represented most commonly among the 1,000 classifiers identified in Monte Carlo cross-validation by the two methods. MiRNAs mir-488, mir-503, and mir-647 were identified as potential reference miRNAs for future studies, based on the stability of their expression patterns across the 77 cases and the two case-groups. Our findings reinforce efforts to profile miRNA expression patterns for better prognostication of stage I NSCLC. Cancer Res; 70(1); 36–45