bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Mirk/Dyrk1B Maintains the Viability of Quiescent Pancreatic Cancer Cells by Reducing Levels of Reactive Oxygen Species
Authors: Deng Xiaobing , Ewton Daina Z. , Friedman Eileen
Published: March 2024

Abstract
The kinase Mirk/dyrk1B mediated the clonogenic growth of pancreatic cancer cells in earlier studies. It is now shown that Mirk levels increased 7-fold in SU86.86 pancreatic cancer cells when over a third of the cells were accumulated in a quiescent G0 state, defined by Hoechst/Pyronin Y staining. Depletion of Mirk by a doxycycline-inducible short hairpin RNA increased the G0 fraction to ∼50%, suggesting that Mirk provided some function in G0. Mirk reduced the levels of reactive oxygen species (ROS) in quiescent cultures of SU86.86 cells and of Panc1 cells by increasing transcription of the antioxidant genes ferroxidase, superoxide dismutase (SOD)2, and SOD3. These genes were functional antioxidant genes in pancreatic cancer cells because ectopic expression of SOD2 and ferroxidase in Mirk-depleted cells lowered ROS levels. Quiescent pancreatic cancer cells quickly lost viability when depleted of Mirk because of elevated ROS levels, exhibiting up to 4-fold less colony-forming activity and 4-fold less capability for dye exclusion. As a result, reduction of ROS by N-acetyl cysteine led to more viable cells. Mirk also destabilizated cyclin D1 and D3 in quiescent cells. Thus, quiescent pancreatic cancer cells depleted of Mirk became less viable because they were damaged by ROS, and had increased levels of G1 cyclins to prime cells to escape quiescence. [Cancer Res 2009;69(8):3317–24]
Data from MicroRNA Signature of Primary Pigmented Nodular Adrenocortical Disease: Clinical Correlations and Regulation of Wnt Signaling
Authors: Iliopoulos Dimitrios , Bimpaki Eirini I. , Nesterova Maria , Stratakis Constantine A.
Published: March 2024

Abstract
MicroRNAs comprise a novel group of gene regulators implicated in the development of different types of cancer; however, their role in primary pigmented nodular adrenocortical disease (PPNAD) has not been investigated. PPNAD is a bilateral adrenal hyperplasia often associated with Carney complex, a multiple neoplasia syndrome; both disorders are caused by protein kinase A (PKA) regulatory subunit type 1A (PRKARIA)–inactivating mutations. We identified a 44-microRNA gene signature of PPNAD after comparing PPNAD with normal adrenal samples. Specifically, 33 microRNAs were up-regulated and 11 down-regulated in PPNAD relative to normal tissues. These results were validated by stem loop real-time PCR analysis. Comparison of microRNA microarray data with clinicopathologic variables revealed a negative correlation (r = −0.9499) between let-7b expression and cortisol levels in patients with PPNAD. Integration of microRNA microarray with serial analysis of gene expression data together with bioinformatic algorithm predictions revealed nine microRNA-gene target pairs with a potential role in adrenal pathogenesis. Using a PPNAD cell line, we showed that miR-449 was up-regulated and identified its direct target, WNT1-inducible signaling pathway protein 2 (WISP2); in addition, pharmacologic inhibition of PKA resulted in the up-regulation of miR-449 leading to the suppression of WISP2. Overall, we investigated, for the first time, the microRNA profile and its clinical significance in PPNAD; these data also suggest that PKA, via microRNA regulation, affects the Wnt signaling pathway, which through expression and clinical studies is suspected to be a primary mediator of PRKAR1A-related tumorigenesis. [Cancer Res 2009;69(8):3278–82]
Data from Identification of Smyd4 as a Potential Tumor Suppressor Gene Involved in Breast Cancer Development
Authors: Hu Liping , Zhu Yiwei Tony , Qi Chao , Zhu Yi-Jun
Published: March 2024

Abstract
To identify genes involved in breast tumorigenesis, we applied the retroviral LoxP-Cre system to a nontumorigenic mouse mammary epithelial cell line NOG8 to create random chromosome deletion/translocation. We found that the disruption of one allele of Smyd4 (SET and MYND domain containing 4) gene through chromosome translocation led to tumorigenesis. The expression of Smyd4 was markedly decreased in tumor cells. Re-expression of Smyd4 resulted in growth suppression of tumor cells and inhibition of tumor formation in nude mice. Furthermore, the RNA interference–mediated suppression of Smyd4 expression in human MCF10A mammary epithelial cells caused their growth in soft agar. Microarray studies revealed that platelet-derived growth factor receptor α polypeptide (Pdgfr-α) was highly expressed in tumor cells compared with NOG8 cells. Re-expression of Smyd4 significantly reduced the expression of Pdgfr-α in tumor cells. In human breast cancers, reverse transcription-PCR results revealed that Smyd4 expression was totally silenced in 2 of 10 specimens. These findings indicate that Smyd4, as a potential tumor suppressor, plays a critical role in breast carcinogenesis at least partly through inhibiting the expression of Pdgfr-α, and could be a novel target for improving treatment of breast cancer. [Cancer Res 2009;69(9):4067–72]
Data from Interleukin 12 Stimulates IFN-γ–Mediated Inhibition of Tumor-Induced Regulatory T-Cell Proliferation and Enhances Tumor Clearance
Authors: Cao Xuefang , Leonard Karen , Collins Lynne I. , Cai Sheng F. , Mayer Joshua C. , Payton Jacqueline E. , Walter Michael J. , Piwnica-Worms David , Schreiber Robert D. , Ley Timothy J.
Published: March 2024

Abstract
To define the factors that modulate regulatory T (Treg) cells in the tumor setting, we cocultured various tumor cells with either purified Treg cells, or with unfractionated splenocytes. We found that Treg expansion occurred only with unfractionated splenocytes, suggesting that accessory cells and/or factors produced by them play an essential role in tumor-induced Treg expansion. We performed gene expression profiling on tumor-associated Treg cells to identify candidate signaling molecules and studied their effects on tumor-induced Treg expansion. We inadvertently discovered that interleukin (IL)-12 treatment blocked Treg expansion in an IL-12 receptor–dependent fashion. Additional studies showed that IL-12 acts by stimulating IFN-γ mediated inhibition of Treg cell proliferation, which may partially account for the antitumor effects of IL-12. Furthermore, IL-12 treatment was found to decrease IL-2 production, which may lead to IFN-γ–independent inhibition of Treg cells, as IL-2 is required for their survival and expansion. Mechanistic studies revealed that IFN-γ signaling directly causes cell cycle arrest in Treg cells. This study shows that an IL-12–IFN-γ axis can suppress tumor-induced Treg proliferation. This mechanism may counteract the ability of Treg cells to promote tumor growth in vivo. [Cancer Res 2009;69(22):8700–9]
Data from Low-Density Lipoprotein Receptor-Related Protein 1 Promotes Cancer Cell Migration and Invasion by Inducing the Expression of Matrix Metalloproteinases 2 and 9
Authors: Song Heesang , Li Yonghe , Lee Jiyeon , Schwartz Alan L. , Bu Guojun
Published: March 2024

Abstract
The low-density lipoprotein receptor-related protein 1 (LRP1) is a multifunctional endocytic receptor involved in the metabolism of various extracellular ligands, including proteinases, that play critical roles in tumor invasion. Although several studies have shown an increased expression of LRP1 in cancer cells, its function in tumor development and progression remains largely unclear. Here, we reveal a novel mechanism by which LRP1 induces the expression of matrix metalloproteinase 2 (MMP2) and MMP9 and thereby promotes the migration and invasion of human glioblastoma U87 cells. Knockdown of LRP1 expression greatly decreased U87 cell migration and invasion, which was rescued by the forced expression of a functional LRP1 minireceptor. Inhibition of ligand binding to LRP1 by a specific antagonist, receptor-associated protein, also led to reduced cancer cell migration and invasion. Because MMPs play critical roles in cancer cell migration and invasion, we examined the expression of several MMPs and found that the expression of functional MMP2 and MMP9 was selectively decreased in LRP1 knockdown cells. More importantly, decreased cell migration and invasion of LRP1 knockdown cells were completely rescued by exogenous expression of MMP2 or MMP9, suggesting that these MMPs are likely downstream targets of LRP1-mediated signaling. We further show that the level of phosphorylated extracellular signal-regulated kinase (ERK) was significantly decreased in LRP1-silenced cells, suggesting that ERK is a potential mediator of LRP1-regulated MMP2 and MMP9 expression in U87 cells. Together, our data strongly suggest that LRP1 promotes glioblastoma cell migration and invasion by regulating the expression and function of MMP2 and MMP9 perhaps via an ERK-dependent signaling pathway. [Cancer Res 2009;69(3):879–86]
Data from Methylation-Mediated Repression of GADD45α in Prostate Cancer and Its Role as a Potential Therapeutic Target
Authors: Ramachandran Kavitha , Gopisetty Gopal , Gordian Edna , Navarro Loida , Hader Christiane , Reis Isildinha M. , Schulz Wolfgang A. , Singal Rakesh
Published: March 2024

Abstract
Defects in apoptotic pathway contribute to uncontrolled proliferation of cancer cells and confer resistance to chemotherapy. Growth arrest and DNA damage inducible, alpha (GADD45α) is up-regulated on docetaxel treatment and may contribute to docetaxel-mediated cytotoxicity. We examined the mechanism of regulation of GADD45α in prostate cancer cells and the effect of its up-regulation on sensitivity to docetaxel chemotherapy. Expression of GADD45α in PC3 cells was higher than that in Du145 and LNCaP cells (17- and 12-fold, respectively; P < 0.05). Although the proximal promoter region was unmethylated in all three cell lines, methylation of a 4 CpG region upstream of the proximal promoter correlated inversely with gene expression levels. Methylation was reversed by treatment of Du145 and LNCaP cells with DNA methyltransferase inhibitors, leading to reactivation of GADD45α expression in these cells. The 5′ 4 CpG region was also frequently methylated in prostate cancer tissues. Methylation of this region correlated inversely with gene expression in prostate cancer and benign prostate tissues. The methyl binding protein MeCP2 was associated with the methylated 4 CpGs in Du145 cells, and knockdown of MeCP2 in these cells (Du145 MeCP2−) led to a significantly increased expression of GADD45α (3-fold; P = 0.035) without affecting the methylation status of the gene. Enhanced sensitivity to docetaxel was observed by up-regulation of GADD45α in Du145 cells by recombinant expression of GADD45α or pretreatment with 5-azacytidine. Our results show that GADD45α is epigenetically repressed and is a potential target for treatment of prostate cancer. [Cancer Res 2009;69(4):1527–35]
Data from Functional Genomic Analysis Identified Epidermal Growth Factor Receptor Activation as the Most Common Genetic Event in Oral Squamous Cell Carcinoma
Authors: Sheu Jim Jinn-Chyuan , Hua Chun-Hung , Wan Lei , Lin Ying-Ju , Lai Ming-Tsung , Tseng Hsien-Chang , Jinawath Natini , Tsai Ming-Hsui , Chang Nai-Wen , Lin Chin-Fen , Lin Chyi-Chyang , Hsieh Lie-Jiau , Wang Tian-Li , Shih Ie-Ming , Tsai Fuu-Jen
Published: March 2024

Abstract
A 250K single-nucleotide polymorphism array was used to study subchromosomal alterations in oral squamous cell carcinoma (OSCC). The most frequent amplification was found at 7p11.2 in 9 of 29 (31%) oral cancer patients. Minimal genomic mapping verified a unique amplicon spanning from 54.6 to 55.3 Mb on chromosome 7, which contains SEC61G and epidermal growth factor receptor (EGFR). Results from fluorescence in situ hybridization, transcriptome, and immunohistochemistry analyses indicated that the expression level of EGFR, but not of SEC61G, was up-regulated and tightly correlated with DNA copy number in 7p11.2 amplified tumors. Among the members of the erbB family, EGFR (HER1) was found to be the most frequently amplified and highly expressed gene in both human and mouse oral tumors (P < 0.01). Genes for downstream effectors of EGFR, including KRAS, mitogen-activated protein kinase 1, and CCND1, were also found amplified or mutated, which resulted in activation of EGFR signaling in 55% of OSCC patients. Head and neck squamous cancer cells with different EGFR expression levels showed differential sensitivity to antitumor effects of AG1478, a potent EGFR inhibitor. AG1478-induced EGFR inactivation significantly suppressed tumor development and progression in a mouse oral cancer model. Our data suggest that EGFR signaling is important in oral cancer development and that anti-EGFR therapy would benefit patients who carry the 7p11.2 amplicon in their tumors. [Cancer Res 2009;69(6):2568–76]
Data from Reprogramming T Lymphocytes for Melanoma Adoptive Immunotherapy by T-Cell Receptor Gene Transfer with Lentiviral Vectors
Authors: Bobisse Sara , Rondina Maria , Merlo Anna , Tisato Veronica , Mandruzzato Susanna , Amendola Mario , Naldini Luigi , Willemsen Ralph A. , Debets Reno , Zanovello Paola , Rosato Antonio
Published: March 2024

Abstract
T-cell receptor (TCR) gene transfer for cancer immunotherapy is limited by the availability of large numbers of tumor-specific T cells. TCR α and β chains were isolated from a highly lytic HLA-A2–restricted cytotoxic T lymphocyte (CTL) clone recognizing the melanoma-associated Melan-A/MART-1 antigen and inserted into a lentiviral vector carrying a bidirectional promoter capable of robust and coordinated expression of the two transgenes. Lentiviral vector–based gene delivery systems have shown increased transfer efficiency and transgene expression compared with the widely used γ-retroviral vectors. This vector performed more efficiently than a γ-retrovirus–based vector containing the same expression cassette, resulting in a T-cell population with 60% to 80% of transgenic TCR expression with mainly CD8+ intermediate effector phenotype. Transgenic T cells specifically produced cytokine in response to and killed antigen-expressing melanoma cells, retained an overlapping functional avidity in comparison with the TCR donor CTL clone, and exerted significant therapeutic effects in vivo upon adoptive transfer in melanoma-bearing severe combined immunodeficient mice. Optical imaging showed their accumulation in the tumor site. Overall, our results indicate that lentiviral vectors represent a valid tool for stable and high-intensity expression of transgenic TCR and support clinical exploitation of this approach for therapeutic application. [Cancer Res 2009;69(24):9385–94]
Data from Coordinated Expression of Stathmin Family Members by Far Upstream Sequence Element-Binding Protein-1 Increases Motility in Non–Small Cell Lung Cancer
Authors: Singer Stephan , Malz Mona , Herpel Esther , Warth Arne , Bissinger Michaela , Keith Martina , Muley Thomas , Meister Michael , Hoffmann Hans , Penzel Roland , Gdynia Georg , Ehemann Volker , Schnabel Philipp Albert , Kuner Ruprecht , Huber Peter , Schirmacher Peter , Breuhahn Kai
Published: March 2024

Abstract
Dynamic instability of the microtubule network modulates processes such as cell division and motility, as well as cellular morphology. Overexpression of the microtubule-destabilizing phosphoprotein stathmin is frequent in human malignancies and represents a promising therapeutic target. Although stathmin inhibition gives rise to antineoplastic effects, additional and functionally redundant microtubule-interacting proteins may attenuate the efficiency of this therapeutic approach. We have systematically analyzed the expression and potential protumorigenic effects of stathmin family members in human non–small cell lung cancer (NSCLC). Both stathmin and stathmin-like 3 (SCLIP) were overexpressed in adenocarcinoma as well as squamous cell carcinoma (SCC) tissues and induced tumor cell proliferation, migration, and matrix invasion in respective cell lines. Accordingly, reduced stathmin and SCLIP levels affected cell morphology and were associated with a less malignant phenotype. Combined inhibition of both factors caused additive effects on tumor cell motility, indicating partial functional redundancy. Because stathmin and SCLIP expression significantly correlated in NSCLC tissues, we searched for common upstream regulators and identified the far upstream sequence element-binding protein-1 (FBP-1) as a pivotal inducer of several stathmin family members. Our results indicate that the coordinated overexpression of microtubule-destabilizing factors by FBP-1 is a critical step to facilitate microtubule dynamics and subsequently increases proliferation and motility of tumor cells. [Cancer Res 2009;69(6):2234–43]
Data from Strongly Enhanced Antitumor Activity of Trastuzumab and Pertuzumab Combination Treatment on HER2-Positive Human Xenograft Tumor Models
Authors: Scheuer Werner , Friess Thomas , Burtscher Helmut , Bossenmaier Birgit , Endl Josef , Hasmann Max
Published: March 2024

Abstract
The human epidermal growth factor receptor (HER) family plays an important role in cell survival and proliferation, and is implicated in oncogenesis. Overexpression of HER2 is associated with aggressive disease and poor prognosis. Trastuzumab is a humanized monoclonal antibody targeting HER2 and has proven survival benefit for women with HER2-positive early and metastatic breast cancer. Pertuzumab, another monoclonal antibody, is a HER2 dimerization inhibitor that binds to a different epitope on HER2 than trastuzumab and inhibits HER2 dimer formation with other HER family members such as HER3 and HER1. We investigated the antitumor activity of these agents alone and in combination in HER2-positive breast and non–small cell lung cancer xenografts. Our data show that the combination of trastuzumab and pertuzumab has a strongly enhanced antitumor effect and induces tumor regression in both xenograft models, something that cannot be achieved by either monotherapy. The enhanced efficacy of the combination was also observed after tumor progression during trastuzumab monotherapy. Near-IR fluorescence imaging experiments confirm that pertuzumab binding to tumors is not impaired by trastuzumab pretreatment. Furthermore, we show by in vitro assay that both trastuzumab and pertuzumab potently activate antibody-dependent cellular cytotoxicity. However, our data suggest that the strongly enhanced antitumor activity is mainly due to the differing but complementary mechanisms of action of trastuzumab and pertuzumab, namely inhibition of HER2 dimerization and prevention of p95HER2 formation. [Cancer Res 2009;69(24):9330–6]
Data from Consistent Deregulation of Gene Expression between Human and Murine MLL Rearrangement Leukemias
Authors: Li Zejuan , Luo Roger T. , Mi Shuangli , Sun Miao , Chen Ping , Bao Jingyue , Neilly Mary Beth , Jayathilaka Nimanthi , Johnson Deborah S. , Wang Lili , Lavau Catherine , Zhang Yanming , Tseng Charles , Zhang Xiuqing , Wang Jian , Yu Jun , Yang Huanming , Wang San Ming , Rowley Janet D. , Chen Jianjun , Thirman Michael J.
Published: March 2024

Abstract
Important biological and pathologic properties are often conserved across species. Although several mouse leukemia models have been well established, the genes deregulated in both human and murine leukemia cells have not been studied systematically. We performed a serial analysis of gene expression in both human and murine MLL-ELL or MLL-ENL leukemia cells and identified 88 genes that seemed to be significantly deregulated in both types of leukemia cells, including 57 genes not reported previously as being deregulated in MLL-associated leukemias. These changes were validated by quantitative PCR. The most up-regulated genes include several HOX genes (e.g., HOX A5, HOXA9, and HOXA10) and MEIS1, which are the typical hallmark of MLL rearrangement leukemia. The most down-regulated genes include LTF, LCN2, MMP9, S100A8, S100A9, PADI4, TGFBI, and CYBB. Notably, the up-regulated genes are enriched in gene ontology terms, such as gene expression and transcription, whereas the down-regulated genes are enriched in signal transduction and apoptosis. We showed that the CpG islands of the down-regulated genes are hypermethylated. We also showed that seven individual microRNAs (miRNA) from the mir-17-92 cluster, which are overexpressed in human MLL rearrangement leukemias, are also consistently overexpressed in mouse MLL rearrangement leukemia cells. Nineteen possible targets of these miRNAs were identified, and two of them (i.e., APP and RASSF2) were confirmed further by luciferase reporter and mutagenesis assays. The identification and validation of consistent changes of gene expression in human and murine MLL rearrangement leukemias provide important insights into the genetic base for MLL-associated leukemogenesis. [Cancer Res 2009;69(3):OF1109–16]
Data from αvβ3/αvβ5 Integrins-FAK-RhoB: A Novel Pathway for Hypoxia Regulation in Glioblastoma
Authors: Skuli Nicolas , Monferran Sylvie , Delmas Caroline , Favre Gilles , Bonnet Jacques , Toulas Christine , Cohen-Jonathan Moyal Elizabeth
Published: March 2024

Abstract
The presence of hypoxic areas in glioblastoma is an important determinant in tumor response to therapy and, in particular, to radiotherapy. Here we have explored the involvement of integrins, up to now known as regulators of angiogenesis and invasion, in the regulation of tumor hypoxia driven from the tumor cell. We first show that hypoxia induces the recruitment of αvβ3 and αvβ5 integrins to the cellular membrane of U87 and SF763 glioblastoma cells, thereby activating the focal adhesion kinase (FAK). We then show that inhibiting αvβ3 or αvβ5 integrins in hypoxic cells with a specific inhibitor or with siRNA decreases the hypoxia-inducible factor 1α (HIF-1α) intracellular level. This integrin-dependent regulation of HIF-1α is mediated through the regulation of FAK, which in turn activates the small GTPase RhoB, leading to the inhibition of GSK3-β. Furthermore, silencing this pathway in glioma cells of established xenografts dramatically reduces glioma hypoxia, associated with a significant decrease in vessel density. Our present results unravel a new mechanism of hypoxia regulation by establishing the existence of an αvβ3/αvβ5 integrin–dependent loop of hypoxia autoregulation in glioma. Targeting this hypoxia loop may be crucial to optimizing radiotherapy efficiency. [Cancer Res 2009;69(8):3308–16]
Data from Tumor-Infiltrating Regulatory Dendritic Cells Inhibit CD8+ T Cell Function via l-Arginine Metabolism
Authors: Norian Lyse A. , Rodriguez Paulo C. , O'Mara Leigh A. , Zabaleta Jovanny , Ochoa Augusto C. , Cella Marina , Allen Paul M.
Published: March 2024

Abstract
Dendritic cells (DC) have a critical effect on the outcome of adaptive immune responses against growing tumors. Whereas it is generally assumed that the presence of phenotypically mature DCs should promote protective antitumor immunity, evidence to the contrary does exist. We describe here a novel mechanism by which tumor-infiltrating dendritic cells (TIDC) actively contribute to the suppression of protective CD8+ T-cell–based antitumor immunity. Using the BALB/NeuT model of spontaneously arising mammary carcinoma, we found that canonical MHC II+/CD11b+/CD11chigh TIDCs act as regulatory DCs to suppress CD8+ T-cell function, resulting in diminished T-cell–based antitumor immunity in vivo. Stimulation of naive T cells with regulatory TIDCs resulted in an altered cell fate program characterized by minimal T-cell expansion, impaired IFNγ production, and anergy. Suppression by regulatory TIDCs overcame stimulatory signals provided by standard DCs, occurred in the absence of cognate interactions with T cells, and was mediated primarily by arginase metabolism of l-arginine. Immunosuppressive TIDCs were found in every murine tumor type examined and were phenotypically distinct from tumor-infiltrating CD11cint-low/CD11b+/Gr-1+ myeloid-derived suppressor cells. Thus, within the tumor microenvironment, MHC II+ TIDCs can function as potent suppressors of CD8+ T-cell immunity. [Cancer Res 2009;69(7):3086–94]
Data from Lysine-Specific Demethylase 1 Is Strongly Expressed in Poorly Differentiated Neuroblastoma: Implications for Therapy
Authors: Schulte Johannes H. , Lim Soyoung , Schramm Alexander , Friedrichs Nicolaus , Koster Jan , Versteeg Rogier , Ora Ingrid , Pajtler Kristian , Klein-Hitpass Ludger , Kuhfittig-Kulle Steffi , Metzger Eric , Schüle Roland , Eggert Angelika , Buettner Reinhard , Kirfel Jutta
Published: March 2024

Abstract
Aberrant epigenetic changes in DNA methylation and histone acetylation are hallmarks of most cancers, whereas histone methylation was previously considered to be irreversible and less versatile. Recently, several histone demethylases were identified catalyzing the removal of methyl groups from histone H3 lysine residues and thereby influencing gene expression. Neuroblastomas continue to remain a clinical challenge despite advances in multimodal therapy. Here, we address the functional significance of the chromatin-modifying enzyme lysine-specific demethylase 1 (LSD1) in neuroblastoma. LSD1 expression correlated with adverse outcome and was inversely correlated with differentiation in neuroblastic tumors. Differentiation of neuroblastoma cells resulted in down-regulation of LSD1. Small interfering RNA–mediated knockdown of LSD1 decreased cellular growth, induced expression of differentiation-associated genes, and increased target gene–specific H3K4 methylation. Moreover, LSD1 inhibition using monoamine oxidase inhibitors resulted in an increase of global H3K4 methylation and growth inhibition of neuroblastoma cells in vitro. Finally, targeting LSD1 reduced neuroblastoma xenograft growth in vivo. Here, we provide the first evidence that a histone demethylase, LSD1, is involved in maintaining the undifferentiated, malignant phenotype of neuroblastoma cells. We show that inhibition of LSD1 reprograms the transcriptome of neuroblastoma cells and inhibits neuroblastoma xenograft growth. Our results suggest that targeting histone demethylases may provide a novel option for cancer therapy. [Cancer Res 2009;69(5):2065–71]
Data from Progressive Chromatin Repression and Promoter Methylation of CTNNA1 Associated with Advanced Myeloid Malignancies
Authors: Ye Ying , McDevitt Michael A. , Guo Mingzhou , Zhang Wei , Galm Oliver , Gore Steven D. , Karp Judith E. , Maciejewski Jaroslaw P. , Kowalski Jeanne , Tsai Hua-Ling , Gondek Lukasz P. , Tsai Hsing-Chen , Wang Xiaofei , Hooker Craig , Smith B. Douglas , Carraway Hetty E. , Herman James G.
Published: March 2024

Abstract
Complete loss or deletion of the long arm of chromosome 5 is frequent in myelodysplastic syndrome (MDS) and acute myelogenous leukemia (AML). The putative gene(s) deleted and responsible for the pathogenesis of these poor prognosis hematologic disorders remain controversial. This study is a comprehensive analysis of previously implicated and novel genes for epigenetic inactivation in AML and MDS. In 146 AML cases, methylation of CTNNA1 was frequent, and more common in AML patients with 5q deletion (31%) than those without 5q deletion (14%), whereas no methylation of other 5q genes was observed. In 31 MDS cases, CTNNA1 methylation was only found in high-risk MDS (≥RAEB2), but not in low-risk MDS (CTNNA1 methylation might be important in the transformation of MDS to AML. CTNNA1 expression was lowest in AML/MDS patients with CTNNA1 methylation, although reduced expression was found in some patients without promoter methylation. Repressive chromatin marks (H3K27me3) at the promoter were identified in CTNNA1-repressed AML cell lines and primary leukemias, with the most repressive state correlating with DNA methylation. These results suggest progressive, acquired epigenetic inactivation at CTNNA1, including histone modifications and promoter CpG methylation, as a component of leukemia progression in patients with both 5q− and non-5q– myeloid malignancies. [Cancer Res 2009;69(21):8482–90]
Data from ADP-Ribosylation Factor 6 Regulates Glioma Cell Invasion through the IQ-Domain GTPase-Activating Protein 1-Rac1–Mediated Pathway
Authors: Hu Bo , Shi Binhai , Jarzynka Michael J. , Yiin Jia-Jean , D'Souza-Schorey Crislyn , Cheng Shi-Yuan
Published: March 2024

Abstract
A common pathobiological feature of malignant gliomas is the insidious infiltration of single tumor cells into the brain parenchyma, rendering these deadly tumors virtually incurable with available therapies. In this study, we report that ADP-ribosylation factor 6 (ARF6), a Ras superfamily small GTPase, is abundantly expressed in invasive human glioma cells. Cellular depletion of ARF6 by small interfering RNA decreased Rac1 activation, impaired HGF-stimulated and serum-stimulated glioma cell migration in vitro, and markedly decreased the invasive capacity of invasive glioma in the brain. Furthermore, ectopic expression of ARF6 in glioma cells promoted cell migration via the activation of Rac1. Upon stimulation of glioma cells with HGF, we show that IQ-domain GTPase-activating protein 1 (IQGAP1) is recruited and overlaps with ARF6 at the leading edge of migrating cells. However, cellular depletion of ARF6 abrogated this recruitment of IQGAP1 and attenuated the formation of surface protrusions. ARF6 forms complexes with Rac1 and IQGAP1 in glioma cells upon HGF stimulation, and knockdown of IQGAP1 significantly inhibits ARF6-induced Rac1 activation and cell migration. Taken together, these data suggest that ARF6-mediated Rac1 activation is essential for glioma cell invasion via a signaling pathway that requires IQGAP1. [Cancer Res 2009;69(3):794–801]
Data from Overexpression of the Cellular DEK Protein Promotes Epithelial Transformation In vitro and In vivo
Authors: Wise-Draper Trisha M. , Mintz-Cole Rachael A. , Morris Teresa A. , Simpson David S. , Wikenheiser-Brokamp Kathryn A. , Currier Mark A. , Cripe Timothy P. , Grosveld Gerard C. , Wells Susanne I.
Published: March 2024

Abstract
High levels of expression of the human DEK gene have been correlated with numerous human malignancies. Intracellular DEK functions have been described in vitro and include DNA supercoiling, DNA replication, RNA splicing, and transcription. We have shown that DEK also suppresses cellular senescence, apoptosis, and differentiation, thus promoting cell growth and survival in monolayer and organotypic epithelial raft models. Such functions are likely to contribute to cancer, but direct evidence to implicate DEK as an oncogene has remained elusive. Here, we show that in line with an early role in tumorigenesis, murine papilloma formation in a classical chemical carcinogenesis model was reduced in DEK knockout mice. Additionally, human papillomavirus E6/E7, hRas, and DEK cooperated in the transformation of keratinocytes in soft agar and xenograft establishment, thus also implicating DEK in tumor promotion at later stages. Finally, adenoviral DEK depletion via short hairpin RNA expression resulted in cell death in human tumor cells in vitro and in vivo, but did not significantly affect differentiated epithelial cells. Taken together, our data uncover oncogenic DEK activities as postulated from its frequent up-regulation in human malignancies, and suggest that the targeted suppression of DEK may become a strategic approach to the treatment of cancer. [Cancer Res 2009;69(5):1792–9]
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 2024

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 The Steroid Receptor Coactivator-1 Regulates Twist Expression and Promotes Breast Cancer Metastasis
Authors: Qin Li , Liu Zhaoliang , Chen Hongwu , Xu Jianming
Published: March 2024

Abstract
In breast cancer, steroid receptor coactivator-1 (SRC-1) expression positively correlates with HER2 expression and poor prognosis. In mouse mammary tumor virus–polyoma middle T (PyMT) breast cancer mouse model, SRC-1 strongly promotes mammary tumor metastasis. However, the molecular targets and mechanisms that mediate the role of SRC-1 in metastasis are unknown. In this study, SRC-1 wild-type (WT) and knockout (KO) cell lines were developed from the mammary tumors of WT/PyMT and KO/PyMT mice. WT cells exhibited strong migration and invasion capabilities, reduced E-cadherin and β-catenin epithelial markers, gained N-cadherin and vimentin mesenchymal markers, and formed undifferentiated invasive structures in three-dimensional culture. In contrast, KO cells showed slow migration and invasion, retained E-cadherin, had less N-cadherin and vimentin, and developed partially differentiated three-dimensional structures. Importantly, WT cells expressed Twist, a master regulator of metastasis, at significantly higher levels versus KO cells. SRC-1 knockdown in WT cells reduced Twist expression, whereas SRC-1 restoration in KO cells also rescued Twist expression. Furthermore, SRC-1 was found to coactivate Twist transcription through physical interaction with the transcription factor PEA3 at the proximal Twist promoter. Accordingly, Twist knockdown in WT cells increased E-cadherin and reduced cell invasion and metastasis, and Twist expression in KO cells decreased E-cadherin and increased cell invasion. SRC-1 knockdown in human breast cancer cells also decreased Twist, cell migration, and invasion. Therefore, SRC-1 promotes breast cancer invasiveness and metastasis by coactivating PEA3-mediated Twist expression. Intervention of SRC-1 function may provide new strategies to inhibit breast cancer metastasis. [Cancer Res 2009;69(9):3819–27]
Data from Blockade of a Chemokine, CCL2, Reduces Chronic Colitis-Associated Carcinogenesis in Mice
Authors: Popivanova Boryana Konstantinova , Kostadinova Feodora Ivanova , Furuichi Kengo , Shamekh Mohamed M. , Kondo Toshikazu , Wada Takashi , Egashira Kensuke , Mukaida Naofumi
Published: March 2024

Abstract
Accumulating evidence indicates the crucial contribution of chronic inflammation to various types of carcinogenesis, including colon carcinoma associated with ulcerative colitis and asbestosis-induced malignant mesothelioma. Ulcerative colitis–associated colon carcinogenesis can be recapitulated in mice by azoxymethane administration followed by repetitive dextran sulfate sodium ingestion. In the course of this carcinogenesis process, the expression of a macrophage-tropic chemokine, CCL2, was enhanced together with intracolonic massive infiltration of macrophages, which were a major source of cyclooxygenase (COX)-2, a crucial mediator of colon carcinogenesis. Mice deficient in CCL2-specific receptor, CCR2, exhibited less macrophage infiltration and lower tumor numbers with attenuated COX-2 expression. Moreover, CCL2 antagonists decreased intracolonic macrophage infiltration and COX-2 expression, attenuated neovascularization, and eventually reduced the numbers and size of colon tumors, even when given after multiple colon tumors have developed. These observations identify CCL2 as a crucial mediator of the initiation and progression of chronic colitis–associated colon carcinogenesis and suggest that targeting CCL2 may be useful in treating colon cancers, particularly those associated with chronic inflammation. [Cancer Res 2009;69(19):7884–92]
Data from The EGF/CSF-1 Paracrine Invasion Loop Can Be Triggered by Heregulin β1 and CXCL12
Authors: Hernandez Lorena , Smirnova Tatiana , Kedrin Dmitriy , Wyckoff Jeffrey , Zhu Liyin , Stanley E. Richard , Cox Dianne , Muller William J. , Pollard Jeffrey W. , Van Rooijen Nico , Segall Jeffrey E.
Published: March 2024

Abstract
An important step in the process of metastasis from the primary tumor is invasive spread into the surrounding stroma. Using an in vivo invasion assay, we have previously shown that imposed gradients of epidermal growth factor (EGF) or colony-stimulating factor-1 (CSF-1) can induce invasion through an EGF/CSF-1 paracrine loop between cancer cells and macrophages. We now report that invasion induced by other ligands also relies on this EGF/CSF-1 paracrine invasive loop. Using an in vivo invasion assay, we show that MTLn3 breast cancer cells overexpressing ErbB3 exhibit enhanced invasion compared with control MTLn3 cells in response to the ErbB3 ligand HRG-β1. The invasive response of both MTLn3-ErbB3 and transgenic MMTV-Neu tumors to HRG-β1 is inhibited by blocking EGF receptor, CSF-1 receptor, or macrophage function, indicating that invasiveness to HRG-β1 is dependent on the EGF/CSF-1 paracrine loop. Furthermore, we show that CXCL12 also triggers in vivo invasion of transgenic MMTV-PyMT tumors in an EGF/CSF-1–dependent manner. Although the invasion induced by HRG-β1 or CXCL12 is dependent on the EGF/CSF-1 paracrine loop, invasion induced by EGF is not dependent on HRG-β1 or CXCL12 signaling, showing an asymmetrical relationship between different ligand/receptor systems in driving invasion. Our results identify a stromal/tumor interaction that acts as an engine underlying invasion induced by multiple ligands. [Cancer Res 2009;69(7):3221–7]
Data from Correction of the Abnormal Trafficking of Primary Myelofibrosis CD34+ Cells by Treatment with Chromatin-Modifying Agents
Authors: Wang Xiaoli , Zhang Wei , Ishii Takefumi , Sozer Selcuk , Wang Jiapeng , Xu Mingjiang , Hoffman Ronald
Published: March 2024

Abstract
The abnormal trafficking of CD34+ cells is a unique characteristic of primary myelofibrosis (PMF). We have further studied the behavior of PMF CD34+ cells by examining their homing to the marrow and the spleens of nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Following the infusion of PMF and normal granulocyte colony-stimulating factor–mobilized peripheral blood (mPB) CD34+ cells into NOD/SCID mice, reduced numbers of PMF CD34+ cells and granulocyte-macrophage colony-forming unit (CFU-GM) compared with mPB were detected in the marrow of these mice, whereas similar numbers of PMF and mPB CD34+ cells and CFU-GM homed to their spleens. The abnormal homing of PMF CD34+ cells was associated with reduced expression of CXCR4, but was not related to the presence of JAK2V617F. The sequential treatment of PMF CD34+ cells with the chromatin-modifying agents 5-aza-2′-deoxycytidine (5azaD) and trichostatin A (TSA), but not treatment with small molecule inhibitors of JAK2, resulted in the generation of increased numbers of CD34+CXCR4+ cells, which was accompanied by enhanced homing of PMF CD34+ cells to the marrow but not the spleens of NOD/SCID mice. Following 5azaD/TSA treatment, JAK2V617F-negative PMF hematopoietic progenitor cells preferentially homed to the marrow but not the spleens of recipient mice. Our data suggest that PMF CD34+ cells are characterized by a reduced ability to home to the marrow but not the spleens of NOD/SCID mice and that this homing defect can be corrected by sequential treatment with chromatin-modifying agents. [Cancer Res 2009;69(19):7612–8]
Data from Inhibition of the p38 Kinase Suppresses the Proliferation of Human ER-Negative Breast Cancer Cells
Authors: Chen Lu , Mayer Julie Ann , Krisko Tibor I. , Speers Corey W. , Wang Tao , Hilsenbeck Susan G. , Brown Powel H.
Published: March 2024

Abstract
p38 kinases are members of the mitogen-activated protein kinase family that transduce signals from various environmental stresses, growth factors, and steroid hormones. p38 is highly expressed in aggressive and invasive breast cancers. Increased levels of activated p38 are markers of poor prognosis. In this study, we tested the hypothesis that blockade of p38 signaling would inhibit breast cancer cell proliferation. We studied breast cancer cell proliferation and cell cycle regulation upon p38 blockade by using three independent approaches: dominant-negative (DN) constructs, small interfering RNA (siRNA), and small molecule inhibitors. p38α and p38δ are the most abundant isoforms expressed by all examined human breast tumors and breast cancer cell lines. Expression of a DN p38 inhibited both anchorage-dependent and -independent proliferation of MDA-MB-468 cells. Silencing of p38α, but not p38δ, using siRNA suppressed MDA-MB-468 cell proliferation. Pharmacologic inhibitors of p38 significantly inhibited the proliferation of p53 mutant and ER-negative breast cancer cells. Whereas p38 has previously been considered as a mediator of stress-induced apoptosis, we propose that p38 may have dual activities regulating survival and proliferation depending on the expression of p53. Our data suggest that p38 mediates the proliferation signal in breast cancer cells expressing mutant but not wild-type p53. Because most ER-negative breast tumors express mutant p53, our results provide the foundation for future development of p38 inhibitors to target p38 for the treatment of p53 mutant and ER-negative breast cancers. [Cancer Res 2009;69(23):8853–61]
Data from Extracellular Signal-Regulated Kinase Positively Regulates the Oncogenic Activity of MCT-1 in Diffuse Large B-Cell Lymphoma
Authors: Dai Bojie , Zhao X. Frank , Hagner Patrick , Shapiro Paul , Mazan-Mamczarz Krystyna , Zhao Shuchun , Natkunam Yasodha , Gartenhaus Ronald B.
Published: March 2024

Abstract
The MCT-1 oncogene was originally identified from lymphoma cell lines. Herein we establish that MCT-1 is highly expressed in 85% of human diffuse large B-cell lymphomas (DLBCL) and that knocking down MCT-1 by a specific short hairpin RNA in DLBCL cells induces apoptosis, supporting a critical role for MCT-1 in DLBCL cell survival. However, the mechanism underlying MCT-1 regulation is largely unknown. We find that MCT-1 is phosphorylated and up-regulated by extracellular signal-regulated kinase (ERK). Furthermore, by using a small inhibitory molecule targeting ERK, we interrupted MCT-1 phosphorylation and stability. Significantly, cells with distinct levels of MCT-1 protein displayed differential sensitivity to ERK inhibitor–induced apoptosis. Treatment with the ERK inhibitor showed marked in vivo antitumor activity in a human DLBCL xenograft model. Our findings establish a functional molecular interaction between MCT-1 and the MEK/ERK signaling pathway and suggest that the activation of MCT-1 function by its upstream kinase ERK plays an important role in lymphomagenesis. [Cancer Res 2009;69(19):7835–43]
Data from Protein Kinase CK2 Regulates Cytoskeletal Reorganization during Ionizing Radiation–Induced Senescence of Human Mesenchymal Stem Cells
Authors: Wang Daojing , Jang Deok-Jin
Published: March 2024

Abstract
Human mesenchymal stem cells (hMSC) are critical for tissue regeneration. How hMSC respond to genotoxic stresses and potentially contribute to aging and cancer remain underexplored. We showed that ionizing radiation induced cellular senescence of hMSC over a period of 10 days, showing a critical transition between days 3 and 6. This was confirmed by senescence-associated β-galactosidase staining, protein expression profiles of key cell cycle regulators (retinoblastoma protein, p53, p21waf1/Cip1, and p16INK4A), and senescence-associated secretory phenotypes (interleukin-8, interleukin-12, GRO, and MDC). We observed dramatic cytoskeletal reorganization of hMSC through reduction of myosin-10, redistribution of myosin-9, and secretion of profilin-1. Using a SILAC-based phosphoproteomics method, we detected significant reduction of myosin-9 phosphorylation at Ser1943, coinciding with its redistribution. Importantly, through treatment with cell-permeable inhibitors (4,5,6,7-tetrabromo-1H-benzotriazole and 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole) and gene knockdown using RNA interference, we identified CK2, a kinase responsible for myosin-9 phosphorylation at Ser1943, as a key factor contributing to the radiation-induced senescence of hMSC. We showed that individual knockdown of CK2 catalytic subunits CK2α and CK2α′ induced hMSC senescence. However, only knockdown of CK2α resulted in morphologic phenotypes resembling those of radiation-induced senescence. These results suggest that CK2α and CK2α′ play differential roles in hMSC senescence progression, and their relative expression might represent a novel regulatory mechanism for CK2 activity. [Cancer Res 2009;69(20):8200–7]
Data from 4-1BB Ligand as an Effective Multifunctional Immunomodulator and Antigen Delivery Vehicle for the Development of Therapeutic Cancer Vaccines
Authors: Sharma Rajesh K. , Schabowsky Rich-Henry , Srivastava Abhishek K. , Elpek Kutlu G. , Madireddi Shravan , Zhao Hong , Zhong Zhenping , Miller Robert W. , MacLeod Kathryn J. , Yolcu Esma S. , Shirwan Haval
Published: March 2024

Abstract
Therapeutic subunit vaccines based on tumor-associated antigens (TAA) represent an attractive approach for the treatment of cancer. However, poor immunogenicity of TAAs requires potent adjuvants for therapeutic efficacy. We recently proposed the tumor necrosis factor family costimulatory ligands as potential adjuvants for therapeutic vaccines and, hence, generated a soluble form of 4-1BBL chimeric with streptavidin (SA-4-1BBL) that has pleiotropic effects on cells of innate, adaptive, and regulatory immunity. We herein tested whether these effects can translate into effective cancer immunotherapy when SA-4-1BBL was also used as a vehicle to deliver TAAs in vivo to dendritic cells (DCs) constitutively expressing the 4-1BB receptor. SA-4-1BBL was internalized by DCs upon receptor binding and immunization with biotinylated antigens conjugated to SA-4-1BBL resulted in increased antigen uptake and cross-presentation by DCs, leading to the generation of effective T-cell immune responses. Conjugate vaccines containing human papillomavirus 16 E7 oncoprotein or survivin as a self-TAA had potent therapeutic efficacy against TC-1 cervical and 3LL lung carcinoma tumors, respectively. Therapeutic efficacy of the vaccines was associated with increased CD4+ T and CD8+ T-cell effector and memory responses and higher intratumoral CD8+ T effector/CD4+CD25+Foxp3+ T regulatory cell ratio. Thus, potent pleiotropic immune functions of SA-4-1BBL combined with its ability to serve as a vehicle to increase the delivery of antigens to DCs in vivo endow this molecule with the potential to serve as an effective immunomodulatory component of therapeutic vaccines against cancer and chronic infections. Cancer Res; 70(10); 3945–54. ©2010 AACR.