bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Lowering Bone Mineral Affinity of Bisphosphonates as a Therapeutic Strategy to Optimize Skeletal Tumor Growth Inhibition In vivo
Authors: Fournier Pierrick G.J. , Daubiné Florence , Lundy Mark W. , Rogers Michael J. , Ebetino Frank H. , Clézardin Philippe
Published: March 2024

Abstract
Bisphosphonates bind avidly to bone mineral and are potent inhibitors of osteoclast-mediated bone destruction. They also exhibit antitumor activity in vitro. Here, we used a mouse model of human breast cancer bone metastasis to examine the effects of risedronate and NE-10790, a phosphonocarboxylate analogue of the bisphosphonate risedronate, on osteolysis and tumor growth. Osteolysis was measured by radiography and histomorphometry. Tumor burden was measured by fluorescence imaging and histomorphometry. NE-10790 had a 70-fold lower bone mineral affinity compared with risedronate. It was 7-fold and 8,800-fold less potent than risedronate at reducing, respectively, breast cancer cell viability in vitro and bone loss in ovariectomized animals. We next showed that risedronate given at a low dosage in animals bearing human B02-GFP breast tumors reduced osteolysis by inhibiting bone resorption, whereas therapy with higher doses also inhibited skeletal tumor burden. Conversely, therapy with NE-10790 substantially reduced skeletal tumor growth at a dosage that did not inhibit osteolysis, a higher dosage being able to also reduce bone destruction. The in vivo antitumor activity of NE-10790 was restricted to bone because it did not inhibit the growth of subcutaneous B02-GFP tumor xenografts nor the formation of B16-F10 melanoma lung metastases. Moreover, NE-10790, in combination with risedronate, reduced both osteolysis and skeletal tumor burden, whereas NE-10790 or risedronate alone only decreased either tumor burden or osteolysis, respectively. In conclusion, our study shows that decreasing the bone mineral affinity of bisphosphonates is an effective therapeutic strategy to inhibit skeletal tumor growth in vivo. [Cancer Res 2008;68(21):8945–53]
Data from Impaired Bub1 Function In vivo Compromises Tension-Dependent Checkpoint Function Leading to Aneuploidy and Tumorigenesis
Authors: Schliekelman Mark , Cowley Dale O. , O'Quinn Ryan , Oliver Trudy G. , Lu Lucy , Salmon E.D. , Van Dyke Terry
Published: March 2024

Abstract
Bub1 is a serine/threonine kinase originally described as a core component of the spindle assembly checkpoint (SAC) mechanism in yeast. Bub1 binding at kinetochores has been reported to be required for SAC function and localization of other SAC components. A proper SAC is believed to be essential for murine embryonic development, as all previously described null mutations in SAC components in mice cause embryonic lethality. We produced mice harboring a Bub1 mutant allele lacking exons 2 and 3, resulting in a hypomorphic mutant expressed at <5% of wild-type levels. Despite this significant reduction, homozygous mutant animals are viable on a mixed 129P2/B6 or FVB background but display increased tumorigenesis with aging, whereas mice with a C57Bl/6J background die perinatally. Bub1 mutant murine embryonic fibroblasts (MEFs) display defects in chromosome congression to the metaphase plate, severe chromosome missegregation, and aneuploidy accompanied by high levels of premature senescence. Mutant MEFs have a robust SAC in response to nocodazole treatment but an impaired response to Taxol. Mutant MEFs also show reduced kinetochore localization of BubR1, but not of Mad2. The significant reduction in SAC response to Taxol, but not nocodazole, coupled with the reduced binding of BubR1, but not Mad2, indicates that Bub1 is particularly critical for the SAC response to a lack of tension on kinetochores. Thus, Bub1 is essential for proper chromosome segregation, a defect that can lead to severe phenotypes, including perinatal lethality and a predisposition to cancer. [Cancer Res 2009;69(1):45–54]
Data from CXCL13 Is Highly Produced by Sézary Cells and Enhances Their Migratory Ability via a Synergistic Mechanism Involving CCL19 and CCL21 Chemokines
Authors: Picchio Maria Cristina , Scala Enrico , Pomponi Debora , Caprini Elisabetta , Frontani Marina , Angelucci Irene , Mangoni Antonella , Lazzeri Cristina , Perez Marie , Remotti Daniele , Bonoldi Emanuela , Benucci Roberto , Baliva Giannandrea , Lombardo Giuseppe Alfonso , Napolitano Monica , Russo Giandomenico , Narducci Maria Grazia
Published: March 2024

Abstract
Chemokine and chemokine receptors expressed by normal and neoplastic lymphocytes play a key role in cell recruitment into skin and lymph nodes. The aim of this study was to get further insights into the role of chemokines in pathogenesis and progression of cutaneous T-cell lymphoma (CTCL) with particular regard to Sézary Syndrome (SS), a CTCL variant with blood involvement. Here, we show that functional CXCL13 homeostatic chemokine is strongly up-regulated in SS cells, well-detectable in skin lesions and lymph nodes, and measurable at high concentration in plasma of SS patients, at different levels during disease progression. Furthermore, we show that the addition of CXCL13 to CCL19 or to CCL21, the selective CCR7 agonists responsible for lymph node homing, strongly enhances the migration of CCR7+ SS cells. We also show that neutralization of the CCR7 receptor strongly impairs CCL19/21-induced chemotaxis of SS cells both in the absence or presence of CXCL13. Additional experiments performed to investigate the survival, adhesion, and metalloproteases secretion indicate that CXCL13 combined with CCL19 and CCL21 mainly affects the chemotaxis of SS cells. Our findings suggest that this newly described CXCL13 expression in SS represents a new pathogenetic mechanism of diagnostic significance. [Cancer Res 2008;68(17):7137–46]
Data from Epigenetic Modification of CCAAT/Enhancer Binding Protein α Expression in Acute Myeloid Leukemia
Authors: Hackanson Björn , Bennett Kristi L. , Brena Romulo M. , Jiang Jinmai , Claus Rainer , Chen Shih-Shih , Blagitko-Dorfs Nadya , Maharry Katie , Whitman Susan P. , Schmittgen Thomas D. , Lübbert Michael , Marcucci Guido , Bloomfield Clara D. , Plass Christoph
Published: March 2024

Abstract
Functional loss of CCAAT/enhancer binding protein α (C/EBPα), a master regulatory transcription factor in the hematopoietic system, can result in a differentiation block in granulopoiesis and thus contribute to leukemic transformation. Here, we show the effect of epigenetic aberrations in regulating C/EBPα expression in acute myeloid leukemia (AML). Comprehensive DNA methylation analyses of the CpG island of C/EBPα identified a densely methylated upstream promoter region in 51% of AML patients. Aberrant DNA methylation was strongly associated with two generally prognostically favorable cytogenetic subgroups: inv(16) and t(15;17). Surprisingly, while epigenetic treatment increased C/EBPα mRNA levels in vitro, C/EBPα protein levels decreased. Using a computational microRNA (miRNA) prediction approach and functional studies, we show that C/EBPα mRNA is a target for miRNA-124a. This miRNA is frequently silenced by epigenetic mechanisms in leukemia cell lines, becomes up-regulated after epigenetic treatment, and targets the C/EBPα 3′ untranslated region. In this way, C/EBPα protein expression is reduced in a posttranscriptional manner. Our results indicate that epigenetic alterations of C/EBPα are a frequent event in AML and that epigenetic treatment can result in down-regulation of a key hematopoietic transcription factor. [Cancer Res 2008;68(9):3142–51]
Data from The Taccalonolides: Microtubule Stabilizers That Circumvent Clinically Relevant Taxane Resistance Mechanisms
Authors: Risinger April L. , Jackson Evelyn M. , Polin Lisa A. , Helms Gregory L. , LeBoeuf Desiree A. , Joe Patrick A. , Hopper-Borge Elizabeth , Ludueña Richard F. , Kruh Gary D. , Mooberry Susan L.
Published: March 2024

Abstract
The taccalonolides are a class of structurally and mechanistically distinct microtubule-stabilizing agents isolated from Tacca chantrieri. A crucial feature of the taxane family of microtubule stabilizers is their susceptibility to cellular resistance mechanisms including overexpression of P-glycoprotein (Pgp), multidrug resistance protein 7 (MRP7), and the βIII isotype of tubulin. The ability of four taccalonolides, A, E, B, and N, to circumvent these multidrug resistance mechanisms was studied. Taccalonolides A, E, B, and N were effective in vitro against cell lines that overexpress Pgp and MRP7. In addition, taccalonolides A and E were highly active in vivo against a doxorubicin- and paclitaxel-resistant Pgp-expressing tumor, Mam17/ADR. An isogenic HeLa-derived cell line that expresses the βIII isotype of tubulin was generated to evaluate the effect of βIII-tubulin on drug sensitivity. When compared with parental HeLa cells, the βIII-tubulin–overexpressing cell line was less sensitive to paclitaxel, docetaxel, epothilone B, and vinblastine. In striking contrast, the βIII-tubulin–overexpressing cell line showed greater sensitivity to all four taccalonolides. These data cumulatively suggest that the taccalonolides have advantages over the taxanes in their ability to circumvent multiple drug resistance mechanisms. The ability of the taccalonolides to overcome clinically relevant mechanisms of drug resistance in vitro and in vivo confirms that the taccalonolides represent a valuable addition to the family of microtubule-stabilizing compounds with clinical potential. [Cancer Res 2008;68(21):8881–8]
Data from Chemotherapy Induces Tumor Clearance Independent of Apoptosis
Authors: Guerriero Jennifer L. , Ditsworth Dara , Fan Yongjun , Zhao Fangping , Crawford Howard C. , Zong Wei-Xing
Published: March 2024

Abstract
Dysregulation of apoptosis is associated with the development of human cancer and resistance to anticancer therapy. The ultimate goal of cancer treatment is to selectively induce cancer cell death and overcome drug resistance. A deeper understanding of how a given chemotherapy affects tumor cell death is needed to develop strategically designed anticancer agents. Here, we use a xenograft mouse tumor system generated from genetically defined cells deficient in apoptosis to examine the involvement of multiple forms of cell death induced by cyclophosphamide (CP), a DNA alkylating agent commonly used in chemotherapy. We find that although apoptosis facilitates tumor regression, it is dispensable for complete tumor regression as other forms of cell death are activated. Sporadic necrosis is observed in both apoptosis-competent and deficient tumors evident by tumor cell morphology, extracellular release of high mobility group box 1 protein, and activation of innate immune cells in CP-treated tumors. Our findings indicate that in apoptosis-deficient tumors, necrosis may play a fundamental role in tumor clearance by stimulating the innate immune response. [Cancer Res 2008;68(23):9595–600]
Data from Genetic Variants in Apoptosis and Immunoregulation-Related Genes Are Associated with Risk of Chronic Lymphocytic Leukemia
Authors: Enjuanes Anna , Benavente Yolanda , Bosch Francesc , Martín-Guerrero Idoia , Colomer Dolors , Pérez-Álvarez Susana , Reina Oscar , Ardanaz Maria T. , Jares Pedro , García-Orad Africa , Pujana Miguel A. , Montserrat Emili , de Sanjosé Silvia , Campo Elias
Published: March 2024

Abstract
To identify low-penetrance susceptibility alleles for chronic lymphocytic leukemia (CLL), we performed a case-control study genotyping 768 single-nucleotide polymorphisms (SNP) in 692 cases of CLL and 738 controls. We investigated nonsynonymous SNPs, SNPs with potential functional effect, and tag SNPs in regulatory gene regions in a total of 172 genes involved in cancer biology. After adjustment for multiple testing, we found a strong association between CLL risk and six genetic variants: CCNH (rs2266690, V270A), APAF1 (rs17028658, 3′region), IL16 (rs4505265, first intron), CASP8 (rs1045485, D302H), NOS2A (rs2779251, promoter), and CCR7 (rs3136687, intron 1). We found association with CLL susceptibility and 22 haplotypes in APAF1, IL6, TNFRSF13B, IL16, CASP3, CCR7, LTA/TNF, BAX, BCL2, CXCL12, CASP10/CASP8, CASP1, CCL2, BAK1, and IL1A candidate genes. Finally, we evaluated using public data sets the potential functional effect on gene expression levels of the CLL associated genetic variants detected in regulatory regions. Minor alleles for APAF1 and IL16 were associated with lower mRNA levels; no expression differences were observed for CCR7, whereas NOS2A could not be assessed. This study suggests that common genetic variation in apoptosis- and immunoregulation-related genes is associated with the CLL risk. [Cancer Res 2008;68(24):10178–86]
Data from New Derivatives of Vitamin B12 Show Preferential Targeting of Tumors
Authors: Waibel Robert , Treichler Hansjörg , Schaefer Niklaus G. , van Staveren Dave R. , Mundwiler Stefan , Kunze Susanne , Küenzi Martin , Alberto Roger , Nüesch Jakob , Knuth Alexander , Moch Holger , Schibli Roger , Schubiger Pius August
Published: March 2024

Abstract
Rapidly growing cells show an increased demand for nutrients and vitamins. The objective of our work is to exploit the supply route of vitamin B12 to deliver new derivatives of this vital vitamin to hyperproliferative cells. To date, radiolabeled (57Co and 111In) vitamin B12 derivatives showed labeling of tumor tissue but also undesired high accumulation of radioactivity in normal tissue. By abolishing the interaction of a tailored vitamin B12 derivative to its transport protein transcobalamin II and therefore interrupting transcobalamin II receptor and megalin mediated uptake in normal tissue, preferential accumulation of a radiolabeled vitamin in cancer tissue could be accomplished. We identified transcobalamin I on tumors as a possible new receptor for this preferential accumulation of vitamin-mediated targeting. The low systemic distribution of radioactivity and the high tumor to blood ratio opens the possibility of a more successful clinical application of vitamin B12 for imaging or therapy. [Cancer Res 2008;68(8):2904–11]
Data from High Frequency of LMAN1 Abnormalities in Colorectal Tumors with Microsatellite Instability
Authors: Roeckel Nina , Woerner Stefan M. , Kloor Matthias , Yuan Yan-Ping , Patsos Georgios , Gromes Roland , Kopitz Juergen , Gebert Johannes
Published: March 2024

Abstract
Glycosyl epitopes have been identified as tumor-specific markers in colorectal tumors and various lines of evidence indicate the significance of altered synthesis, transport, and secretion of glycoproteins in tumorigenesis. However, aberrant glycosylation has been largely ignored in microsatellite unstable (MSI-H) colorectal tumors. Therefore, we analyzed mutation frequencies of genes of the cellular glycosylation machinery in MSI-H tumors, focusing on frameshift mutations in coding MNRs (cMNRs). Among 28 candidate genes, LMAN1/ERGIC53, a mannose-specific lectin mediating endoplasmatic reticulum (ER)-to-Golgi transit of glycosylated proteins, showed high mutation frequency in MSI-H colorectal cancer cell lines (52%; 12 of 23), carcinomas (45%; 72 of 161), and adenomas (40%; 8 of 20). Biallelic mutations were observed in 17% (4 of 23) of MSI-H colorectal cancer cell lines. LMAN1 was found to be transcribed but truncated protein remained undetectable in these LMAN1-mutant cell lines. Immunohistochemical and molecular analysis of LMAN1-mutated carcinomas and adenomas revealed regional loss of LMAN1 expression due to biallelic LMAN1 cMNR frameshift mutations. In LMAN1-deficient colorectal cancer cell lines, secretion of the LMAN1 client protein α-1-antitrypsin (A1AT), an inhibitor of angiogenesis and tumor growth, was significantly impaired but could be restored upon LMAN1 re-expression. These results suggest that LMAN1 mutational inactivation is a frequent and early event potentially contributing to MSI-H tumorigenesis. [Cancer Res 2009;69(1):292–9]
Data from Targeting Endoplasmic Reticulum Stress and Akt with OSU-03012 and Gefitinib or Erlotinib to Overcome Resistance to Epidermal Growth Factor Receptor Inhibitors
Authors: Wang Yu-Chieh , Kulp Samuel K. , Wang Dasheng , Yang Chih-Cheng , Sargeant Aaron M. , Hung Jui-Hsiang , Kashida Yoko , Yamaguchi Mamoru , Chang Geen-Dong , Chen Ching-Shih
Published: March 2024

Abstract
Preexisting and acquired resistance to epidermal growth factor receptor (EGFR) inhibitors limits their clinical usefulness in patients with advanced non–small cell lung cancer (NSCLC). This study characterizes the efficacy and mechanisms of the combination of gefitinib or erlotinib with OSU-03012, a celecoxib-derived antitumor agent, to overcome EGFR inhibitor resistance in three NSCLC cell lines, H1155, H23, and A549. The OSU-03012/EGFR inhibitor combination induced pronounced apoptosis in H1155 and H23 cells, but not in A549 cells, suggesting a correlation between drug sensitivity and basal phospho-Akt levels independently of EGFR expression status. Evidence indicates that this combination facilitates apoptosis through both Akt signaling inhibition and up-regulation of endoplasmic reticulum (ER) stress–induced, GADD153-mediated pathways. For example, ectopic expression of constitutively active Akt significantly attenuated the inhibitory effect on cell survival, and small interfering RNA–mediated knockdown of GADD153 protected cells from undergoing apoptosis in response to drug cotreatments. Furthermore, the OSU-03012/EGFR inhibitor combination induced GADD153-mediated up-regulation of death receptor 5 expression and subsequent activation of the extrinsic apoptosis pathway. It is noteworthy that the ER stress response induced by this combination was atypical in that the cytoprotective pathway was not engaged. In addition, in vivo suppression of tumor growth and modulation of intratumoral biomarkers were observed in a H1155 tumor xenograft model in nude mice. These data suggest that the concomitant modulation of Akt and ER stress pathways with the OSU-03012/EGFR inhibitor combination represents a unique approach to overcoming EGFR inhibitor resistance in NSCLC and perhaps other types of cancer with elevated basal Akt activities. [Cancer Res 2008;68(8):2820–30]
Data from Coevolution of Prostate Cancer and Bone Stroma in Three-Dimensional Coculture: Implications for Cancer Growth and Metastasis
Authors: Sung Shian-Ying , Hsieh Chia-Ling , Law Andrew , Zhau Haiyen E. , Pathak Sen , Multani Asha S. , Lim Sharon , Coleman Ilsa M. , Wu Li-Chin , Figg William D. , Dahut William L. , Nelson Peter , Lee Jae K. , Amin Mahul B. , Lyles Robert , Johnstone Peter A.J. , Marshall Fray F. , Chung Leland W.K.
Published: March 2024

Abstract
Human bone stromal cells, after three-dimensional coculture with human prostate cancer (PCa) cells in vitro, underwent permanent cytogenetic and gene expression changes with reactive oxygen species serving as mediators. The evolved stromal cells are highly inductive of human PCa growth in mice, and expressed increased levels of extracellular matrix (versican and tenascin) and chemokine (BDFN, CCL5, CXCL5, and CXCL16) genes. These genes were validated in clinical tissue and/or serum specimens and could be the predictors for invasive and bone metastatic PCa. These results, combined with our previous observations, support the concept of permanent genetic and behavioral changes of PCa epithelial cells after being either cocultured with prostate or bone stromal cells as three-dimensional prostate organoids or grown as tumor xenografts in mice. These observations collectively suggest coevolution of cancer and stromal cells occurred under three-dimensional growth condition, which ultimately accelerates cancer growth and metastasis. [Cancer Res 2008;68(23):9996–10003]
Data from Loss of the CBX7 Gene Expression Correlates with a Highly Malignant Phenotype in Thyroid Cancer
Authors: Pallante Pierlorenzo , Federico Antonella , Berlingieri Maria Teresa , Bianco Mimma , Ferraro Angelo , Forzati Floriana , Iaccarino Antonino , Russo Maria , Pierantoni Giovanna Maria , Leone Vincenza , Sacchetti Silvana , Troncone Giancarlo , Santoro Massimo , Fusco Alfredo
Published: March 2024

Abstract
Using gene expression profiling, we found that the CBX7 gene was drastically down-regulated in six thyroid carcinoma cell lines versus control cells. The aims of this study were to determine whether CBX7 is related to the thyroid cancer phenotype and to try to identify new tools for the diagnosis and prognosis of thyroid cancer. We thus evaluated CBX7 expression in various snap-frozen and paraffin-embedded thyroid carcinoma tissues of different degrees of malignancy by quantitative reverse transcription-PCR and immunohistochemistry, respectively. CBX7 expression progressively decreased with malignancy grade and neoplasia stage. Indeed, it decreased in an increasing percentage of cases going from benign adenomas to papillary (PTC), follicular, and anaplastic (ATC) thyroid carcinomas. This finding coincides with results obtained in rat and mouse models of thyroid carcinogenesis. CBX7 loss of heterozygosity occurred in 36.8% of PTC and in 68.7% of ATC. Restoration of CBX7 expression in thyroid cancer cells reduced growth rate, with a retention in the G1 phase of the cell cycle, suggesting that CBX7 can contribute to the proliferation of the transformed thyroid cells. In conclusion, loss of CBX7 expression correlates with a highly malignant phenotype in thyroid cancer patients. [Cancer Res 2008;68(16):6770–8]
Data from PCPH/ENTPD5 Expression Confers to Prostate Cancer Cells Resistance against Cisplatin-Induced Apoptosis through Protein Kinase Cα–Mediated Bcl-2 Stabilization
Authors: Villar Joaquín , Quadri Humair S. , Song Insun , Tomita York , Tirado Oscar M. , Notario Vicente
Published: March 2024

Abstract
Prostate cancer (PCa) frequently develops antiapoptotic mechanisms and acquires resistance to anticancer drugs. Therefore, identifying PCa drug resistance determinants should facilitate designing more effective chemotherapeutic regimens. Recently, we described that the PCPH protein becomes highly expressed in human prostatic intraepithelial neoplasia and in PCa, and that the functional interaction between PCPH and protein kinase Cδ (PKCδ) increases the invasiveness of human PCa. Here, we report that the functional interaction between PCPH and a different PKC isoform, PKCα, confers resistance against cisplatin-induced apoptosis to PCa cells. This interaction elicits a mechanism ultimately resulting in the posttranslational stabilization and subsequent elevated expression of Bcl-2. Stable knockdown of either PCPH, mt-PCPH, or PKCα in PCa cells decreased Ser70-phosphorylated Bcl-2 and total Bcl-2 protein, thereby increasing their cisplatin sensitivity. Conversely, forced expression of the PCPH protein or, in particular, of the mt-PCPH oncoprotein increased the levels of phosphorylated PKCα concurrently with those of Ser70-phosphorylated and total Bcl-2 protein, thus promoting cisplatin resistance. Consistently, Bcl-2 knockdown sensitized PCa cells to cisplatin treatment and, more importantly, reversed the cisplatin resistance of PCa cells expressing the mt-PCPH oncoprotein. Moreover, reexpression of Bcl-2 in PCPH/mt-PCPH knockdown PCa cells reversed the cisplatin sensitization caused by PCPH or mt-PCPH down-regulation. These findings identify PCPH and mt-PCPH as important participants in the chemotherapy response of PCa cells, establish a role for PCPH-PKCα-Bcl-2 functional interactions in the drug response process, and imply that targeting PCPH expression before, or simultaneously with, chemotherapy may improve the treatment outcome for PCa patients. [Cancer Res 2009;69(1):102–10]
Data from Sequential Transcription Factor Targeting for Diffuse Large B-Cell Lymphomas
Authors: Cerchietti Leandro C. , Polo Jose M. , Da Silva Gustavo F. , Farinha Pedro , Shaknovich Rita , Gascoyne Randy D. , Dowdy Steven F. , Melnick Ari
Published: March 2024

Abstract
Transcription factors play a central role in malignant transformation by activating or repressing waves of downstream target genes. Therapeutic targeting of transcription factors can reprogram cancer cells to lose their advantages in growth and survival. The BCL6 transcriptional repressor plays a central role in the pathogenesis of diffuse large B-cell lymphomas (DLBCL) and controls downstream checkpoints, including the p53 tumor suppressor gene. We report that a specific inhibitor of BCL6 called BPI can trigger a p53 response in DLBCL cells. This was partially due to induction of p53 activity and partially due to relief of direct repression by BCL6 of p53 target genes. BPI could thus induce a p53-like response even in the presence of mutant p53. Moreover, sequential BCL6 peptide inhibitors followed by p53 peptide or small-molecule activators provided a more powerful antilymphoma effect than either treatment alone by maximally restoring p53 target gene expression. Therefore, tandem targeting of the overlapping BCL6 and p53 transcriptional programs can correct aberrant survival pathways in DLBCL and might provide an effective therapeutic approach to lymphoma therapy. [Cancer Res 2008;68(9):3361–9]
Data from Mechanisms by which E-Selectin Regulates Diapedesis of Colon Cancer Cells under Flow Conditions
Authors: Tremblay Pierre-Luc , Huot Jacques , Auger François A.
Published: March 2024

Abstract
Diapedesis, the passage of circulating tumor cells across the endothelium, is a critical determinant in most cases of metastasis. Using a laminar flow chamber and a tissue-engineered blood vessel, we found that E-selectin is required not only for the initial adhesion and rolling of circulating HT-29 colon cancer cells on the endothelium but also for their subsequent diapedesis. These processes require both the intracellular and extracellular domains of E-selectin. We also identified three distinct mechanisms by which circulating cancer cells interact with E-selectin to initiate their diapedesis: formation of a mosaic between cancer cells and endothelial cells, paracellular diapedesis at the junction of three endothelial cells, and transcellular diapedesis. We also obtained evidence indicating that E-selectin–dependent paracellular extravasation is independent of intercellular adhesion molecule and vascular cell adhesion molecule and that it requires the activation of extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase downstream of E-selectin. This is supported by the observation that the adenoviral-mediated expression of the E-selectin mutant Y603F is associated with both an inhibition of ERK and paracellular extravasation. Our study is the first to clearly establish, under dynamic and shear stress conditions, how E-selectin regulates diapedesis of circulating cancer cells. These results provide new insights in understanding the metastatic process. [Cancer Res 2008;68(13):5167–76]
Data from Wnt5A Regulates Expression of Tumor-Associated Antigens in Melanoma via Changes in Signal Transducers and Activators of Transcription 3 Phosphorylation
Authors: Dissanayake Samudra K. , Olkhanud Purevdorj B. , O'Connell Michael P. , Carter Arnell , French Amanda D. , Camilli Tura C. , Emeche Chineye D. , Hewitt Kyle J. , Rosenthal Devin T. , Leotlela Poloko D. , Wade Michael S. , Yang Sherry W. , Brant Larry , Nickoloff Brian J. , Messina Jane L. , Biragyn Arya , Hoek Keith S. , Taub Dennis D. , Longo Dan L. , Sondak Vernon K. , Hewitt Stephen M. , Weeraratna Ashani T.
Published: March 2024

Abstract
There are currently no effective therapies for metastatic melanoma and targeted immunotherapy results in the remission of only a very small percentage of tumors. In this study, we show that the noncanonical Wnt ligand, Wnt5A, can increase melanoma metastasis in vivo while down-regulating the expression of tumor-associated antigens important in eliciting CTL responses (e.g., MART-1, GP100, and tyrosinase). Melanosomal antigen expression is governed by MITF, PAX3, and SOX10 and is inhibited upon signal transducers and activators of transcription 3 (STAT3) activation, via decreases in PAX3 and subsequently MITF expression. Increasing Wnt5A in Wnt5A-low cells activated STAT3, and STAT3 was decreased upon Wnt5A knockdown. Downstream targets such as PAX3, MITF, and MART-1 were also affected by Wnt5A treatment or knockdown. Staining of a melanoma tissue array also highlighted the inverse relationship between MART-1 and Wnt5A expression. PKC activation by phorbol ester mimicked Wnt5A effects, and Wnt5A treatment in the presence of STAT3 or PKC inhibitors did not lower MART-1 levels. CTL activation studies showed that increases in Wnt5A correspond to decreased CTL activation and vice versa, suggesting that targeting Wnt5A before immunotherapy may lead to the enhancement of current targeted immunotherapy for patients with metastatic melanoma. [Cancer Res 2008;68(24):10205–14]
Data from An Immortalization-Dependent Switch in Integrin Function Up-regulates MMP-9 to Enhance Tumor Cell Invasion
Authors: Lamar John M. , Pumiglia Kevin M. , DiPersio C. Michael
Published: March 2024

Abstract
Integrins, the major receptors for cell adhesion to the extracellular matrix, play important roles during tumor progression. However, it is still unclear whether genetic lesions that occur during carcinoma development can lead to altered integrin function, and how changes in integrin function contribute to subsequent carcinoma progression. Loss-of-function mutations in p53 and activating mutations in H-Ras, which immortalize and transform epithelial cells, respectively, are common causal events in squamous cell carcinoma (SCC). Phenotypes resulting from these two genetic lesions promote SCC progression and are, therefore, potential targets for anticancer therapies. We developed a model system of keratinocyte transformation that has allowed us to investigate the individual roles of p53 mutation and oncogenic Ras mutation in the acquisition of integrin α3β1-regulated phenotypes that promote SCC progression. Using this model, we show that keratinocyte immortalization by p53-null mutation causes a switch in α3β1 function that induces matrix metalloproteinase (MMP)-9 gene expression in tumorigenic cells. This acquired α3β1-dependent regulation of MMP-9 was maintained during subsequent transformation by oncogenic Ras, and it promoted invasion of tumorigenic keratinocytes. Our results show that loss of p53 function leads to changes in integrin-mediated gene regulation that occur during SCC progression and play a critical role in tumor cell invasion. [Cancer Res 2008;68(18):7371–9]
Data from Chromatin Immunoprecipitation–on-Chip Reveals Stress-Dependent p53 Occupancy in Primary Normal Cells but Not in Established Cell Lines
Authors: Shaked Helena , Shiff Idit , Kott-Gutkowski Miriam , Siegfried Zahava , Haupt Ygal , Simon Itamar
Published: March 2024

Abstract
The p53 tumor suppressor protein is a transcription factor that plays a key role in the cellular response to stress and cancer prevention. Upon activation, p53 regulates a large variety of genes causing cell cycle arrest, apoptosis, or senescence. We have developed a p53-focused array, which allows us to investigate, simultaneously, p53 interactions with most of its known target sequences using the chromatin immunoprecipitation (ChIP)-on-chip methodology. Applying this technique to multiple cell types under various growth conditions revealed a profound difference in p53 activity between primary cells and established cell lines. We found that, in peripheral blood mononuclear cells, p53 exists in a form that binds only a small subset of its target regions. Upon exposure to genotoxic stress, the extent of targets bound by p53 significantly increased. By contrast, in established cell lines, p53 binds to essentially all of its targets irrespective of stress and cellular fate (apoptosis or arrest). Analysis of gene expression in these established lines revealed little correlation between DNA binding and the induction of gene expression. Our results suggest that nonactivated p53 has limited binding activity, whereas upon activation it binds to essentially all its targets. Additional triggers are most likely required to activate the transcriptional program of p53. [Cancer Res 2008;68(23):9671–7]
Data from GEMS (Gene Expression Metasignatures), a Web Resource for Querying Meta-analysis of Expression Microarray Datasets: 17β-Estradiol in MCF-7 Cells
Authors: Ochsner Scott A. , Steffen David L. , Hilsenbeck Susan G. , Chen Edward S. , Watkins Christopher , McKenna Neil J.
Published: March 2024

Abstract
With large amounts of public expression microrray data being generated by multiple laboratories, it is a significant task for the bench researcher to routinely identify available datasets, and then to evaluate the collective evidence across these datasets for regulation of a specific gene in a given system. 17β-Estradiol stimulation of MCF-7 cells is a widely used model in the growth of breast cancer. Although myriad independent studies have profiled the global effects of this hormone on gene expression in these cells, disparate experimental variables and the limited power of the individual studies have combined to restrict the agreement between them as to the specific gene expression signature elicited by this hormone. To address these issues, we have developed a freely accessible Web resource, Gene Expression MetaSignatures (GEMS) that provides the user a consensus for each gene in the system. We conducted a weighted meta-analysis encompassing over 13,000 genes across 10 independent published datasets addressing the effect of 17β-estradiol on MCF-7 cells at early (3–4 hours) and late (24 hours) time points. In a literature survey of 58 genes previously shown to be regulated by 17β-estradiol in MCF-7 cells, the meta-analysis combined the statistical power of the underlying datasets to call regulation of these genes with nearly 85% accuracy (false discovery rate–corrected P < 0.05). We anticipate that with future expression microarray dataset contributions from investigators, GEMS will evolve into an important resource for the cancer and nuclear receptor signaling communities. [Cancer Res 2009;69(1):23–6]
Data from Phospholipase Cγ1 Is Required for Metastasis Development and Progression
Authors: Sala Gianluca , Dituri Francesco , Raimondi Claudio , Previdi Sara , Maffucci Tania , Mazzoletti Marco , Rossi Cosmo , Iezzi Manuela , Lattanzio Rossano , Piantelli Mauro , Iacobelli Stefano , Broggini Massimo , Falasca Marco
Published: March 2024

Abstract
Cell motility and invasion play an essential role in the development of metastasis. Evidence suggests that the enzyme phospholipase Cγ1 (PLCγ1) may be involved in tumor progression and possibly development of metastasis. In this study, we show that down-regulation of PLCγ1 expression severely impairs activation of the small GTP-binding protein Rac and cell invasion in breast cancer cell lines and U87 in vitro. Experimental metastasis assays in nude mice show that inducible knockdown of PLCγ1 strongly inhibits development of MDA-MB-231–derived lung metastasis and reverts metastasis formation. In addition, analysis of 60 breast cancer patients' tissues revealed an increase of PLCγ1 expression in metastasis compared with the primary tumor in 50% of tissues analyzed. These data show a critical role of PLCγ1 in the metastatic potential of cancer cells, and they further indicate that PLCγ1 inhibition has a therapeutic potential in the treatment of metastasis dissemination. [Cancer Res 2008;68(24):10187–96]
Data from SMAD6 Contributes to Patient Survival in Non–Small Cell Lung Cancer and Its Knockdown Reestablishes TGF-β Homeostasis in Lung Cancer Cells
Authors: Jeon Hyo-Sung , Dracheva Tatiana , Yang Sei-Hoon , Meerzaman Daoud , Fukuoka Junya , Shakoori Abbas , Shilo Konstantin , Travis William D. , Jen Jin
Published: March 2024

Abstract
The malignant transformation in several types of cancer, including lung cancer, results in a loss of growth inhibition by transforming growth factor-β (TGF-β). Here, we show that SMAD6 expression is associated with a reduced survival in lung cancer patients. Short hairpin RNA (shRNA)–mediated knockdown of SMAD6 in lung cancer cell lines resulted in reduced cell viability and increased apoptosis as well as inhibition of cell cycle progression. However, these results were not seen in Beas2B, a normal bronchial epithelial cell line. To better understand the mechanism underlying the association of SMAD6 with poor patient survival, we used a lentivirus construct carrying shRNA for SMAD6 to knock down expression of the targeted gene. Through gene expression analysis, we observed that knockdown of SMAD6 led to the activation of TGF-β signaling through up-regulation of plasminogen activator inhibitor-1 and phosphorylation of SMAD2/3. Furthermore, SMAD6 knockdown activated the c-Jun NH2-terminal kinase pathway and reduced phosphorylation of Rb-1, resulting in increased G0-G1 cell arrest and apoptosis in the lung cancer cell line H1299. These results jointly suggest that SMAD6 plays a critical role in supporting lung cancer cell growth and survival. Targeted inactivation of SMAD6 may provide a novel therapeutic strategy for lung cancers expressing this gene. [Cancer Res 2008;68(23):9686–92]
Data from Cell Motility in Chronic Lymphocytic Leukemia: Defective Rap1 and αLβ2 Activation by Chemokine
Authors: Till Kathleen J. , Harris Robert J. , Linford Andrea , Spiller David G. , Zuzel Mirko , Cawley John C.
Published: March 2024

Abstract
Chemokine-induced activation of α4β1 and αLβ2 integrins (by conformational change and clustering) is required for lymphocyte transendothelial migration (TEM) and entry into lymph nodes. We have previously reported that chemokine-induced TEM is defective in chronic lymphocytic leukemia (CLL) and that this defect is a result of failure of the chemokine to induce polar clustering of αLβ2; engagement of α4β1 and autocrine vascular endothelial growth factor (VEGF) restore clustering and TEM. The aim of the present study was to characterize the nature of this defect in αLβ2 activation and determine how it is corrected. We show here that the αLβ2 of CLL cells is already in variably activated conformations, which are not further altered by chemokine treatment. Importantly, such treatment usually does not cause an increase in the GTP-loading of Rap1, a GTPase central to chemokine-induced activation of integrins. Furthermore, we show that this defect in Rap1 GTP-loading is at the level of the GTPase and is corrected in CLL cells cultured in the absence of exogenous stimuli, suggesting that the defect is the result of in vivo stimulation. Finally, we show that, because Rap1-induced activation of both α4β1 and αLβ2 is defective, autocrine VEGF and chemokine are necessary to activate α4β1 for ligand binding. Subsequently, this binding and both VEGF and chemokine stimulation are all needed for αLβ2 activation for motility and TEM. The present study not only clarifies the nature of the αLβ2 defect of CLL cells but is the first to implicate activation of Rap1 in the pathophysiology of CLL. [Cancer Res 2008;68(20):8429–36]
Data from p53-Inducible Ribonucleotide Reductase (p53R2/RRM2B) Is a DNA Hypomethylation–Independent Decitabine Gene Target That Correlates with Clinical Response in Myelodysplastic Syndrome/Acute Myelogenous Leukemia
Authors: Link Petra A. , Baer Maria R. , James Smitha R. , Jones David A. , Karpf Adam R.
Published: March 2024

Abstract
While the therapeutic activity of the deoxycytidine analogue decitabine is thought to reflect its ability to reactivate methylation-silenced genes, this agent is also known to trigger p53-dependent DNA damage responses. Here, we report that p53-inducible ribonucleotide reductase (p53R2/RRM2B) is a robust transcriptional target of decitabine. In cancer cells, decitabine treatment induces p53R2 mRNA expression, protein expression, and promoter activity in a p53-dependent manner. The mechanism of p53R2 gene induction by decitabine does not seem to be promoter DNA hypomethylation, as the p53R2 5′ CpG island is hypomethylated before treatment. Small interfering RNA (siRNA) targeting of DNA methyltransferase 1 (DNMT1) in wild-type p53 cells leads to genomic DNA hypomethylation but does not induce p53R2, suggesting that DNMT/DNA adduct formation is the molecular trigger for p53R2 induction. Consistent with this idea, only nucleoside-based DNMT inhibitors that form covalent DNA adducts induce p53R2 expression. siRNA targeting of p53R2 reduces the extent of cell cycle arrest following decitabine treatment, supporting a functional role for p53R2 in decitabine-mediated cellular responses. To determine the clinical relevance of p53R2 induction, we measured p53R2 expression in bone marrow samples from 15 myelodysplastic syndrome/acute myelogenous leukemia (MDS/AML) patients undergoing decitabine therapy. p53R2 mRNA and protein were induced in 7 of 13 (54%) and 6 of 9 (67%) patients analyzed, respectively, despite a lack of methylation changes in the p53R2 promoter. Most notably, there was a significant association (P = 0.0047) between p53R2 mRNA induction and clinical response in MDS/AML. These data establish p53R2 as a novel hypomethylation-independent decitabine gene target associated with clinical response. [Cancer Res 2008;68(22):9358–66]
Data from Tumor-Associated Galectin-3 Modulates the Function of Tumor-Reactive T Cells
Authors: Peng Weiyi , Wang Helen Y. , Miyahara Yoshihiro , Peng Guangyong , Wang Rong-Fu
Published: March 2024

Abstract
T cells play an important role in cancer immunosurveillance and tumor destruction. However, tumor cells alter immune responses by modulating immune cells through antigen stimulation and immunoregulatory cytokines. A better understanding of the interplay between tumor cells and T cells might provide new strategies to enhance antitumor immunity. Through an antigen-screening approach using colorectal tumor–reactive T cells, we identified an HLA-DR11–restricted T-cell epitope encoded by KIAA0040 as well as MHC-unrestricted human galectin-3 (Gal-3) expressed by tumor cells. Although the biological function of KIAA0040 remains to be determined, we found that Gal-3 functioned as an immune regulator for direct T-cell activation and function. T-cell activation induced by Gal-3 resulted in T-cell apoptosis. We showed that a high level of expression of Gal-3 promoted tumor growth in vitro and in vivo. Using a mouse tumor model, we showed that delivery of high doses of Gal-3 inhibited tumor-reactive T cells and promoted tumor growth in mice receiving tumor-reactive CD8+ T cells. These findings suggest that Gal-3 may function as an immune regulator to inhibit T-cell immune responses and promote tumor growth, thus providing a new mechanism for tumor immune tolerance. [Cancer Res 2008;68(17):7228–36]
Data from The High-Mobility Group A1a/Signal Transducer and Activator of Transcription-3 Axis: An Achilles Heel for Hematopoietic Malignancies?
Authors: Hillion Joelle , Dhara Surajit , Sumter Takita Felder , Mukherjee Mita , Di Cello Francescopaolo , Belton Amy , Turkson James , Jaganathan Souyma , Cheng Linzhao , Ye Zhaohui , Jove Richard , Aplan Peter , Lin Ying-Wei , Wertzler Kelsey , Reeves Ray , Elbahlouh Ossama , Kowalski Jeanne , Bhattacharya Raka , Resar Linda M. S.
Published: March 2024

Abstract
Although HMGA1 (high-mobility group A1; formerly HMG-I/Y) is an oncogene that is widely overexpressed in aggressive cancers, the molecular mechanisms underlying transformation by HMGA1 are only beginning to emerge. HMGA1 encodes the HMGA1a and HMGA1b protein isoforms, which function in regulating gene expression. To determine how HMGA1 leads to neoplastic transformation, we looked for genes regulated by HMGA1 using gene expression profile analysis. Here, we show that the STAT3 gene, which encodes the signaling molecule signal transducer and activator of transcription 3 (STAT3), is a critical downstream target of HMGA1a. STAT3 mRNA and protein are up-regulated in fibroblasts overexpressing HMGA1a and activated STAT3 recapitulates the transforming activity of HMGA1a in fibroblasts. HMGA1a also binds directly to a conserved region of the STAT3 promoter in vivo in human leukemia cells by chromatin immunoprecipitation and activates transcription of the STAT3 promoter in transfection experiments. To determine if this pathway contributes to HMGA1-mediated transformation, we investigated STAT3 expression in our HMGA1a transgenic mice, all of which developed aggressive lymphoid malignancy. STAT3 expression was increased in the leukemia cells from our transgenics but not in control cells. Blocking STAT3 function induced apoptosis in the transgenic leukemia cells but not in controls. In primary human leukemia samples, there was a positive correlation between HMGA1a and STAT3 mRNA. Moreover, blocking STAT3 function in human leukemia or lymphoma cells led to decreased cellular motility and foci formation. Our results show that the HMGA1a–STAT3 axis is a potential Achilles heel that could be exploited therapeutically in hematopoietic and other malignancies overexpressing HMGA1a. [Cancer Res 2008;68(24):10121–7]
Data from Depletion of Dendritic Cells Delays Ovarian Cancer Progression by Boosting Antitumor Immunity
Authors: Huarte Eduardo , Cubillos-Ruiz Juan R. , Nesbeth Yolanda C. , Scarlett Uciane K. , Martinez Diana G. , Buckanovich Ronald J. , Benencia Fabian , Stan Radu V. , Keler Tibor , Sarobe Pablo , Sentman Charles L. , Conejo-Garcia Jose R.
Published: March 2024

Abstract
Dendritic cells (DC) and cytokines that expand myeloid progenitors are widely used to treat cancer. Here, we show that CD11c+DEC205+ DCs coexpressing α-smooth muscle actin and VE-cadherin home to perivascular areas in the ovarian cancer microenvironment and are required for the maintenance of tumor vasculature. Consequently, depletion of DCs in mice bearing established ovarian cancer by targeting different specific markers significantly delays tumor growth and enhances the effect of standard chemotherapies. Tumor growth restriction was associated with vascular apoptosis after DC ablation followed by necrosis, which triggered an antitumor immunogenic boost. Our findings provide a mechanistic rationale for selectively eliminating tumor-associated leukocytes to promote antitumor immunity while impeding tumor vascularization and to develop more effective DC vaccines based on a better understanding of the tumor microenvironment. [Cancer Res 2008;68(18):7684–91]
Data from Preferential Cytotoxicity of Bortezomib toward Hypoxic Tumor Cells via Overactivation of Endoplasmic Reticulum Stress Pathways
Authors: Fels Diane R. , Ye Jiangbin , Segan Andrew T. , Kridel Steven J. , Spiotto Michael , Olson Michael , Koong Albert C. , Koumenis Constantinos
Published: March 2024

Abstract
Hypoxia is a dynamic feature of the tumor microenvironment that contributes to drug resistance and cancer progression. We previously showed that components of the unfolded protein response (UPR), elicited by endoplasmic reticulum (ER) stress, are also activated by hypoxia in vitro and in vivo animal and human patient tumors. Here, we report that ER stressors, such as thapsigargin or the clinically used proteasome inhibitor bortezomib, exhibit significantly higher cytotoxicity toward hypoxic compared with normoxic tumor cells, which is accompanied by enhanced activation of UPR effectors in vitro and UPR reporter activity in vivo. Treatment of cells with the translation inhibitor cycloheximide, which relieves ER load, ameliorated this enhanced cytotoxicity, indicating that the increased cytotoxicity is ER stress–dependent. The mode of cell death was cell type–dependent, because DLD1 colorectal carcinoma cells exhibited enhanced apoptosis, whereas HeLa cervical carcinoma cells activated autophagy, blocked apoptosis, and eventually led to necrosis. Pharmacologic or genetic ablation of autophagy increased the levels of apoptosis. These results show that hypoxic tumor cells, which are generally more resistant to genotoxic agents, are hypersensitive to proteasome inhibitors and suggest that combining bortezomib with therapies that target the normoxic fraction of human tumors can lead to more effective tumor control. [Cancer Res 2008;68(22):9323–30]