bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Ulcerative Colitis–Associated Colorectal Cancer Arises in a Field of Short Telomeres, Senescence, and Inflammation
Authors: Risques Rosa Ana , Lai Lisa A. , Himmetoglu Cigdem , Ebaee Anoosheh , Li Lin , Feng Ziding , Bronner Mary P. , Al-Lahham Bassel , Kowdley Kris V. , Lindor Keith D. , Rabinovitch Peter S. , Brentnall Teresa A.
Published: March 2024

Abstract
Inflammation plays a role in the progression to cancer and it is linked to the presence of senescent cells. Ulcerative colitis (UC) is a chronic inflammatory disease that predisposes to colorectal cancer. Tumorigenesis in this setting is associated with telomere shortening that can be observed in the nondysplastic epithelium of UC patients with high-grade dysplasia (HGD) or cancer (UC progressors). We hypothesized that a preneoplastic field of inflammation, telomere shortening, and senescence underlies tumor progression in UC progressors. Multiple biopsies of varying histologic grade were collected along the colon of nine UC progressors and analyzed for telomere length, DNA damage, senescence, p53, p16, and chronic and acute inflammation. Twenty biopsies from four UC nonprogressors and twenty-one biopsies from control individuals without UC were also analyzed. Short telomeres and increased DNA damage, senescence, and infiltrating leukocytes were observed in biopsies located less than 10 cm from HGD or cancer. Low-grade dysplasia (LGD) had the shortest telomeres along with the highest levels of senescence and infiltrating leukocytes, whereas HGD biopsies showed the opposite pattern. The expression of p16 and p53 was low in nondysplastic biopsies but progressively increased in LGD and HGD. In addition, high levels of infiltrating leukocytes were associated with telomere shortening, senescence, and reduced p53 expression. These results suggest that dysplasia arises in a preneoplastic field of chronic inflammation, which leads to telomere shortening, DNA damage, and senescence. Our findings argue that senescence acts as a tumor suppressor mechanism that is abrogated during the transition from LGD to HGD in UC. Cancer Res; 71(5); 1669–79. ©2011 AACR.
Data from Silencing of Thrombospondin-1 Is Critical for Myc-Induced Metastatic Phenotypes in Medulloblastoma
Authors: Zhou Limei , Picard Daniel , Ra Young-Shin , Li Meihua , Northcott Paul A. , Hu Yaqi , Stearns Duncan , Hawkins Cynthia , Taylor Michael D. , Rutka James , Der Sandy D. , Huang Annie
Published: March 2024

Abstract
Mechanisms by which c-Myc (Myc) amplification confers aggressive medulloblastoma phenotypes are poorly defined. Here, we show using orthotopic models that high Myc expression promotes cell migration/invasion and induces metastatic tumors, which recapitulate aggressive histologic features of Myc-amplified primary human medulloblastoma. Using ChIP-chip analysis, we identified cell migration and adhesion genes, including Tsp-1/THBS1, ING4, PVRL3, and PPAP2B, as Myc-bound loci in medulloblastoma cells. Expression of Tsp-1 was most consistently and robustly diminished in medulloblastoma cell lines and primary human tumors with high Myc expression (n = 101, P = 0.032). Strikingly, stable Tsp-1 expression significantly attenuated in vitro transformation and invasive/migratory properties of high Myc-expressing medulloblastoma cells without altering cell proliferation, whereas RNA interference–mediated Myc knockdown was consistently accompanied by increased Tsp-1 levels and reduced cell migration and invasion in medulloblastoma cells. Chromatin immunoprecipitation (ChIP) assays revealed colocalization of Myc and obligate partner Max and correlated diminished RNA polymerase II occupancy (∼3-fold decrease, P < 0.01) with increased Myc binding at a core Tsp-1 promoter. Reporter gene and/or gel shift assays confirmed direct repression of Tsp-1 transcription by Myc and also identified JPO2, a Myc interactor associated with metastatic medulloblastoma, as a cofactor in Myc-mediated Tsp-1 repression. These findings indicate the Myc-regulatory network targets Tsp-1 via multiple mechanisms in medulloblastoma transformation, and highlight a novel critical role for Tsp-1 in Myc-mediated aggressive medulloblastoma phenotypes. Cancer Res; 70(20); 8199–210. ©2010 AACR.
Data from Heterotrimerization of the Growth Factor Receptors erbB2, erbB3, and Insulin-like Growth Factor-I Receptor in Breast Cancer Cells Resistant to Herceptin
Authors: Huang Xiaoping , Gao Lizhi , Wang Shuiliang , McManaman James L. , Thor Ann D. , Yang XiaoHe , Esteva Francisco J. , Liu Bolin
Published: March 2024

Abstract
Primary and acquired resistance to the breast cancer drug trastuzumab (Herceptin) is a significant clinical problem. Here, we report enhanced activation of downstream signaling pathways emanating from the growth factor receptors erbB2, erbB3, and insulin-like growth factor-I receptor (IGF-IR) in trastuzumab-resistant breast cancer cells. Interactions between IGF-IR and erbB2 or erbB3 occur exclusively in trastuzumab-resistant cells, where enhanced erbB2-erbB3 interactions are also observed. Moreover, these three receptors form a heterotrimeric complex in resistant cells. erbB3 or IGF-IR knockdown by short hairpin RNA–mediated strategies upregulates p27kip1, inactivates downstream receptor signaling, and resensitizes resistant cells to trastuzumab. Our findings reveal a heterotrimer complex with a key role in trastuzumab resistance. On the basis of our results, we propose that trastuzumab resistance in breast cancer might be overcome by therapeutic strategies that jointly target erbB3, erbB2, and IGF-IR. Cancer Res; 70(3); 1204–14
Data from Activation of Hedgehog Signaling by the Environmental Toxicant Arsenic May Contribute to the Etiology of Arsenic-Induced Tumors
Authors: Fei Dennis Liang , Li Hua , Kozul Courtney D. , Black Kendall E. , Singh Samer , Gosse Julie A. , DiRenzo James , Martin Kathleen A. , Wang Baolin , Hamilton Joshua W. , Karagas Margaret R. , Robbins David J.
Published: March 2024

Abstract
Exposure to the environmental toxicant arsenic, through both contaminated water and food, contributes to significant health problems worldwide. In particular, arsenic exposure is thought to function as a carcinogen for lung, skin, and bladder cancer via mechanisms that remain largely unknown. More recently, the Hedgehog signaling pathway has also been implicated in the progression and maintenance of these same cancers. Based on these similarities, we tested the hypothesis that arsenic may act in part through activating Hedgehog signaling. Here, we show that arsenic is able to activate Hedgehog signaling in several primary and established tissue culture cells as well as in vivo. Arsenic activates Hedgehog signaling by decreasing the stability of the repressor form of GLI3, one of the transcription factors that ultimately regulate Hedgehog activity. We also show, using tumor samples from a cohort of bladder cancer patients, that high levels of arsenic exposure are associated with high levels of Hedgehog activity. Given the important role Hedgehog signaling plays in the maintenance and progression of a variety of tumors, including bladder cancer, these results suggest that arsenic exposure may in part promote cancer through the activation of Hedgehog signaling. Thus, we provide an important insight into the etiology of arsenic-induced human carcinogenesis, which may be relevant to millions of people exposed to high levels of arsenic worldwide. Cancer Res; 70(5); 1981–8
Data from R428, a Selective Small Molecule Inhibitor of Axl Kinase, Blocks Tumor Spread and Prolongs Survival in Models of Metastatic Breast Cancer
Authors: Holland Sacha J. , Pan Alison , Franci Christian , Hu Yuanming , Chang Betty , Li Weiqun , Duan Matt , Torneros Allan , Yu Jiaxin , Heckrodt Thilo J. , Zhang Jing , Ding Pingyu , Apatira Ayodele , Chua Joanne , Brandt Ralf , Pine Polly , Goff Dane , Singh Rajinder , Payan Donald G. , Hitoshi Yasumichi
Published: March 2024

Abstract
Accumulating evidence suggests important roles for the receptor tyrosine kinase Axl in cancer progression, invasion, metastasis, drug resistance, and patient mortality, highlighting Axl as an attractive target for therapeutic development. We have generated and characterized a potent and selective small-molecule inhibitor, R428, that blocks the catalytic and procancerous activities of Axl. R428 inhibits Axl with low nanomolar activity and blocked Axl-dependent events, including Akt phosphorylation, breast cancer cell invasion, and proinflammatory cytokine production. Pharmacologic investigations revealed favorable exposure after oral administration such that R428-treated tumors displayed a dose-dependent reduction in expression of the cytokine granulocyte macrophage colony-stimulating factor and the epithelial-mesenchymal transition transcriptional regulator Snail. In support of an earlier study, R428 inhibited angiogenesis in corneal micropocket and tumor models. R428 administration reduced metastatic burden and extended survival in MDA-MB-231 intracardiac and 4T1 orthotopic (median survival, >80 days compared with 52 days; P < 0.05) mouse models of breast cancer metastasis. Additionally, R428 synergized with cisplatin to enhance suppression of liver micrometastasis. Our results show that Axl signaling regulates breast cancer metastasis at multiple levels in tumor cells and tumor stromal cells and that selective Axl blockade confers therapeutic value in prolonging survival of animals bearing metastatic tumors. Cancer Res; 70(4); 1544–54
Data from mTOR Complex Component Rictor Interacts with PKCζ and Regulates Cancer Cell Metastasis
Authors: Zhang Fei , Zhang Xiaofang , Li Menghui , Chen Peng , Zhang Bin , Guo Hua , Cao Wenfeng , Wei Xiying , Cao Xuchen , Hao Xishan , Zhang Ning
Published: March 2024

Abstract
Epidermal growth factor (EGF) mediates breast cancer cell chemotaxis and metastasis through mechanisms that involve the growth-regulatory mammalian target of rapamycin (mTOR) complex mTORC2, but the mechanisms involved remain obscure. Here, we report that the rapamycin-insensitive mTORC2 component protein Rictor is a critical mediator of metastasis in breast cancer cells. In patients with ductal carcinoma, Rictor expression was associated with increased lymph node metastasis. EGF induced translocation and colocalization of Rictor with protein kinase Cζ (PKCζ), a pivotal molecule in chemotaxis signaling. Further, Rictor coimmunoprecipitated with PKCζ in the absence of the mTORC2 complex. Small interfering RNA–mediated knockdown of Rictor inhibited EGF-induced PKCζ phosphorylation and translocation along with phosphorylation of the key F-actin binding protein cofilin. In parallel, Rictor knockdown reduced cellular chemotactic capacity and ablated pulmonary metastasis in a xenograft mouse model of breast cancer. Our findings identify Rictor as an important mediator of chemotaxis and metastasis in breast cancer cells. Cancer Res; 70(22); 9360–70. ©2010 AACR.
Data from Targeting Activin Receptor-Like Kinase 1 Inhibits Angiogenesis and Tumorigenesis through a Mechanism of Action Complementary to Anti-VEGF Therapies
Authors: Hu-Lowe Dana D. , Chen Enhong , Zhang Lianglin , Watson Katherine D. , Mancuso Patrizia , Lappin Patrick , Wickman Grant , Chen Jeffrey H. , Wang Jianying , Jiang Xin , Amundson Karin , Simon Ronald , Erbersdobler Andreas , Bergqvist Simon , Feng Zheng , Swanson Terri A. , Simmons Brett H. , Lippincott John , Casperson Gerald F. , Levin Wendy J. , Stampino Corrado Gallo , Shalinsky David R. , Ferrara Katherine W. , Fiedler Walter , Bertolini Francesco
Published: March 2024

Abstract
Genetic and molecular studies suggest that activin receptor-like kinase 1 (ALK1) plays an important role in vascular development, remodeling, and pathologic angiogenesis. Here we investigated the role of ALK1 in angiogenesis in the context of common proangiogenic factors [PAF; VEGF-A and basic fibroblast growth factor (bFGF)]. We observed that PAFs stimulated ALK1-mediated signaling, including Smad1/5/8 phosphorylation, nuclear translocation and Id-1 expression, cell spreading, and tubulogenesis of endothelial cells (EC). An antibody specifically targeting ALK1 (anti-ALK1) markedly inhibited these events. In mice, anti-ALK1 suppressed Matrigel angiogenesis stimulated by PAFs and inhibited xenograft tumor growth by attenuating both blood and lymphatic vessel angiogenesis. In a human melanoma model with acquired resistance to a VEGF receptor kinase inhibitor, anti-ALK1 also delayed tumor growth and disturbed vascular normalization associated with VEGF receptor inhibition. In a human/mouse chimera tumor model, targeting human ALK1 decreased human vessel density and improved antitumor efficacy when combined with bevacizumab (anti-VEGF). Antiangiogenesis and antitumor efficacy were associated with disrupted co-localization of ECs with desmin+ perivascular cells, and reduction of blood flow primarily in large/mature vessels as assessed by contrast-enhanced ultrasonography. Thus, ALK1 may play a role in stabilizing angiogenic vessels and contribute to resistance to anti-VEGF therapies. Given our observation of its expression in the vasculature of many human tumor types and in circulating ECs from patients with advanced cancers, ALK1 blockade may represent an effective therapeutic opportunity complementary to the current antiangiogenic modalities in the clinic. Cancer Res; 71(4); 1362–73. ©2011 AACR.
Data from Tie2 Signaling Regulates Osteoclastogenesis and Osteolytic Bone Invasion of Breast Cancer
Authors: Min Yongfen , Ren Xiubao , Vaught David B. , Chen Jin , Donnelly Edwin , Lynch Conor C. , Lin P. Charles
Published: March 2024

Abstract
Breast to bone metastasis is a common occurrence in the majority of patients with advanced breast cancer. The metastases are often incurable and are associated with bone destruction and high rates of morbidity. Understanding the underlying mechanisms of how metastatic tumor cells induce bone destruction is critically important. We previously reported that Tie2, a receptor tyrosine kinase, is significantly increased in human breast cancer tissues compared with normal and benign breast tumors and regulates tumor angiogenesis. In this study, we identify a new function of Tie2 in osteoclastogenesis and osteolytic bone invasion of breast cancer. Tie2 is present in hematopoietic stem/precursor cells. Genetic deletion of Tie2 or neutralization of Tie2 function using soluble Tie2 receptor impaired osteoclastogenesis in an embryonic stem cell differentiation assay. In contrast, deletion of Tie2 has no effect on osteoblastogenesis. As CD11b myeloid cells have the potential to become osteoclasts and Tie2 is present in a certain population of these cells, we isolated Tie2+ and Tie2− myeloid cells. We observed a significant reduction of osteoclastogenesis in Tie2− compared with Tie2+ CD11b cells. Consistently, neutralization of Tie2 activity in vivo significantly inhibited osteolytic bone invasion and tumor growth in a mammary tumor model, which correlated with a significant reduction of osteoclasts and tumor angiogenesis. Collectively, these data reveal a direct and novel role of Tie2 signaling in osteoclast differentiation. These findings identify Tie2 as a therapeutic target for controlling not only tumor angiogenesis but also osteolytic bone metastasis in breast cancer. Cancer Res; 70(7); 2819–28
Data from Disruption of Laminin-Integrin-CD151-Focal Adhesion Kinase Axis Sensitizes Breast Cancer Cells to ErbB2 Antagonists
Authors: Yang Xiuwei H. , Flores Ludmila M. , Li Qinglin , Zhou Pengcheng , Xu Fenghui , Krop Ian E. , Hemler Martin E.
Published: March 2024

Abstract
Resistance to anti-ErbB2 agents is a significant problem in the treatment of human ErbB2+ breast cancers. We show here that adhesion of human ErbB2+ breast cancer cells to basement membrane laminin-5 provides substantial resistance to trastuzumab and lapatinib, agents that respectively target the extracellular and kinase domains of ErbB2. Knockdown of laminin-binding integrins (α6β4, α3β1) or associated tetraspanin protein CD151 reversed laminin-5 resistance and sensitized ErbB2+ cells to trastuzumab and lapatinib. CD151 knockdown, together with trastuzumab treatment, inhibited ErbB2 activation and downstream signaling through Akt, Erk1/2, and focal adhesion kinase (FAK). Hence, ErbB2 function in mammary tumor cells is promoted by integrin-mediated adhesion to laminin-5, with strong support by CD151, leading to signaling through FAK. Consequently, removal or inhibition of any of these components (laminin-5, integrin, CD151, FAK) markedly sensitizes cells to anti-ErbB2 agents. These new insights should be useful when devising strategies for overcoming drug resistance in ErbB2+ cancers. Cancer Res; 70(6); 2256–63
Data from Regulation of Minichromosome Maintenance Gene Family by MicroRNA-1296 and Genistein in Prostate Cancer
Authors: Majid Shahana , Dar Altaf A. , Saini Sharanjot , Chen Yi , Shahryari Varahram , Liu Jan , Zaman Mohd Saif , Hirata Hiroshi , Yamamura Soichiro , Ueno Koji , Tanaka Yuichiro , Dahiya Rajvir
Published: March 2024

Abstract
The minichromosome maintenance (MCM) gene family is essential for DNA replication and is frequently upregulated in various cancers. Here, we examined the role of MCM2 in prostate cancer and the effect of microRNA-1296 (miR-1296), genistein, and trichostatin A (TSA) on the MCM complex. Profiling results showed that expression of MCM genes was higher in tumor samples. Genistein and TSA significantly downregulated the expression of all MCM genes. Genistein, TSA, and small interfering RNA duplexes caused a significant decrease in the S phase of the cell cycle. There was also downregulation of CDT1, CDC7, and CDK2 genes, which govern loading of the MCM complex on chromatin. We also found that miR-1296 was significantly downregulated in prostate cancer samples. In PC3 cells, inhibition of miR-1296 upregulated both MCM2 mRNA and protein, whereas overexpression caused a significant decrease in MCM2 mRNA, protein, and the S phase of the cell cycle. MCM genes are excellent anticancer drug targets because they are essential DNA replication factors that are highly expressed in cancer cells. This is the first report showing anti-MCM effect by miR-1296, genistein, and TSA. TSA is undergoing clinical trials as a prostate cancer treatment but has high toxicity. Genistein, a natural, nontoxic dietary isoflavone, may be an advantageous therapeutic agent for treating prostate cancer. The use of RNA interference is currently being implemented as a gene-specific approach for molecular medicine. The specific downregulation of oncogenes by miR may contribute to novel therapeutic approaches in the treatment of prostate cancer. Cancer Res; 70(7); 2809–18
Data from Extracellular Signal-Regulated Kinase 8–Mediated c-Jun Phosphorylation Increases Tumorigenesis of Human Colon Cancer
Authors: Xu Yan-Ming , Zhu Feng , Cho Yong-Yeon , Carper Andria , Peng Cong , Zheng Duo , Yao Ke , Lau Andy T.Y. , Zykova Tatyana A. , Kim Hong-Gyum , Bode Ann M. , Dong Zigang
Published: March 2024

Abstract
Extracellular signal-regulated kinase 8 (ERK8), a recently discovered member of the mitogen-activated protein kinase protein family, has been less studied than other family members, leaving its physiologic functions mostly unknown. The biological consequences of overexpression of ERK8 in JB6 Cl41 epidermal skin cells or knockdown of ERK8 in HCT15 colorectal cancer cells was studied. Kinase assays and transient transfection experiments were performed to study the signaling pathway between ERK8 and c-Jun. We found that ERK8 is relatively highly expressed in HCT15 human colorectal cancer cells and plays an important role in the promotion and progression of colorectal cancer. ERK8 promoted neoplastic transformation, and knockdown of ERK8 in HCT15 colorectal cancer cells reduced the tumorigenic properties of these cell lines. Furthermore, a direct interaction between ERK8 and c-Jun was shown. With epidermal growth factor treatment, overexpression of ERK8 in JB6 Cl41 cells caused an increased phosphorylation of c-Jun at Ser63 and Ser73, resulting in increased activator protein-1 transactivation. In contrast, knockdown of ERK8 in HCT15 colorectal cancer cells blocked c-Jun phosphorylation. The interaction between ERK8 and c-Jun seems to increase the tumorigenic properties of HCT15 colorectal cancer cells. Thus, ERK8-regulated signaling might serve as a potential therapeutic target in colorectal cancer. Cancer Res; 70(8); 3218–27. ©2010 AACR.
Data from Aberrant Activation of the Androgen Receptor by NF-κB2/p52 in Prostate Cancer Cells
Authors: Nadiminty Nagalakshmi , Lou Wei , Sun Meng , Chen Jun , Yue Jiao , Kung Hsing-Jien , Evans Christopher P. , Zhou Qinghua , Gao Allen C.
Published: March 2024

Abstract
Prostate cancer initiation and progression are uniquely dependent on the androgen receptor (AR). Even when the cancer progresses to a castration-resistant stage, AR signaling remains active via a variety of mechanisms. In the present study, we showed that NF-κB/p52 can activate the AR, resulting in increased transactivation of AR-responsive genes, such as PSA and NKX3.1, in a ligand-independent manner. NF-κB2/p52 enhances nuclear translocation and activation of AR by interacting with its NH2-terminal domain and enhances the recruitment of coactivators such as p300 to the promoters of AR-dependent genes. These results were confirmed in three different prostate cancer cell lines: LAPC-4 (wild-type AR), LNCaP (mutant AR), and C4-2 (castration resistant). Transfection of p52 into LAPC-4 and LNCaP cells (which express low levels of p52) showed increased activation of the endogenous AR. Downregulation of endogenous p52 in C4-2 cells resulted in abrogation of AR constitutive activation. Comparison of the relative effects of p52 and p65 (RelA) showed that p52, but not p65, could activate the AR. Collectively, these findings, together with previous reports that the levels of NF-κB2/p52 are elevated in prostate cancer cells and that active NF-κB2/p52 promotes prostate cancer cell growth in vitro and in vivo, suggest that NF-κB2/p52 may play a critical role in the progression of castration-resistant prostate cancer. Cancer Res; 70(8); 3309–19. ©2010 AACR.
Data from A Unique Pharmacophore for Activation of the Nuclear Orphan Receptor Nur77 In vivo and In vitro
Authors: Liu Jing-jing , Zeng Hui-ni , Zhang Lian-ru , Zhan Yan-yan , Chen Yan , Wang Yuan , Wang Juan , Xiang Shao-hua , Liu Wen-jun , Wang Wei-jia , Chen Hang-zi , Shen Yue-mao , Su Wen-jin , Huang Pei-qiang , Zhang Hong-kui , Wu Qiao
Published: March 2024

Abstract
Nur77 is a steroid orphan receptor that plays a critical role in regulating proliferation, differentiation, and apoptosis, including acting as a switch for Bcl-2 function. We previously reported that the octaketide cytosporone B (Csn-B) is a natural agonist for Nur77. In this study, we synthesized a series of Csn-B analogues and performed a structure-activity analysis that suggested criteria for the development of a unique pharmacophore to activate Nur77. The components of the pharmacophore necessary for binding Nur77 included the benzene ring, the phenolic hydroxyl group, and the acyl chain of the Csn-B scaffold, whereas the key feature for activating the biological function of Nur77 was the ester group. Csn-B analogues that bound Nur77 tightly not only stimulated its transactivation activity but also initiated mitochondrial apoptosis by means of novel cross-talk between Nur77 and BRE, an antiapoptotic protein regulated at the transcriptional level. Notably, the derivative n-amyl 2-[3,5-dihydroxy-2-(1-nonanoyl)phenyl]acetate exhibited greater antitumor activity in vivo than its parent compounds, highlighting particular interest in this compound. Our findings describe a pathway for rational design of Csn-B–derived Nur77 agonists as a new class of potent and effective antitumor agents. Cancer Res; 70(9); 3628–37. ©2010 AACR.
Data from MiR-26a Inhibits Cell Growth and Tumorigenesis of Nasopharyngeal Carcinoma through Repression of EZH2
Authors: Lu Juan , He Ming-Liang , Wang Lu , Chen Ying , Liu Xiong , Dong Qi , Chen Yang-Chao , Peng Ying , Yao Kai-Tai , Kung Hsiang-Fu , Li Xiang-Ping
Published: March 2024

Abstract
Several microRNAs (miRNA) have been implicated in nasopharyngeal carcinoma (NPC), a highly invasive and metastatic cancer that is widely prevalent in southern China. In this study, we report that microRNA miR-26a iscommonly downregulated in NPC specimens and NPC cell lines with important functional consequences. Ectopic expression of miR-26a dramatically suppressed cell proliferation and colony formation by inducing G1-phase cell-cycle arrest. We found that miR-26a strongly reduced the expression of EZH2 oncogene in NPC cells. Similar to the restoring miR-26 expression, EZH2 downregulation inhibited cell growth and cell-cycle progression, whereas EZH2 overexpression rescued the suppressive effect of miR-26a. Mechanistic investigations revealed that miR-26a suppressed the expression of c-myc, the cyclin D3 and E2, and the cyclin-dependent kinase CDK4 and CDK6 while enhancing the expression of CDK inhibitors p14ARF and p21CIP1 in an EZH2-dependent manner. Interestingly, cyclin D2 was regulated by miR-26a but not by EZH2, revealing cyclin D2 asanother direct yet mechanistically distinct target of miR-26a. In clinical specimens, EZH2 was widely overexpressed and its mRNA levels were inversely correlated with miR-26a expression. Taken together, our results indicate that miR-26a functions as a growth-suppressive miRNA in NPC, and that its suppressive effects are mediated chiefly by repressing EZH2 expression. Cancer Res; 71(1); 225–33. ©2010 AACR.
Data from Degradation of MDM2 by the Interaction between Berberine and DAXX Leads to Potent Apoptosis in MDM2-Overexpressing Cancer Cells
Authors: Zhang Xiaoling , Gu Lubing , Li Jiansha , Shah Noopur , He Jing , Yang Lin , Hu Qun , Zhou Muxiang
Published: March 2024

Abstract
Berberine, a natural product derived from a plant used in Chinese herbal medicine, is reported to exhibit anticancer effects; however, its mechanism of action is not clearly defined. Herein, we demonstrate that berberine induces apoptosis in acute lymphoblastic leukemia (ALL) cells by downregulating the MDM2 oncoprotein. The proapoptotic effects of berberine were closely associated with both the MDM2 expression levels and p53 status of a set of ALL cell lines. The most potent apoptosis was induced by berberine in ALL cells with both MDM2 overexpression and a wild-type (wt)-p53, whereas no proapoptotic effect was detected in ALL cells that were negative for MDM2 and wt-p53. In contrast to the conventional chemotherapeutic drug doxorubicin, which induces p53 activation and a subsequent upregulation of MDM2, berberine strongly induced persistent downregulation of MDM2 followed by a steady-state activation of p53. We discovered that downregulation of MDM2 in ALL cells by berberine occurred at a posttranslational level through modulation of death domain-associated protein (DAXX), which disrupted the MDM2–DAXX–HAUSP interactions and thereby promoted MDM2 self-ubiquitination and degradation. Given that MDM2-overexpressing cancer cells are commonly chemoresistant, our findings suggest that this naturally derived agent may have a highly useful role in the treatment of cancer patients with refractory disease. Cancer Res; 70(23); 9895–904. ©2010 AACR.
Data from A NADPH Oxidase–Dependent Redox Signaling Pathway Mediates the Selective Radiosensitization Effect of Parthenolide in Prostate Cancer Cells
Authors: Sun Yulan , St. Clair Daret K. , Xu Yong , Crooks Peter A. , St. Clair William H.
Published: March 2024

Abstract
Cancer cells are usually under higher oxidative stress compared with normal cells. We hypothesize that introducing additional reactive oxygen species (ROS) insults or suppressing antioxidant capacity may selectively enhance cancer cell killing by oxidative stress–generating agents through stress overload or stress sensitization, whereas normal cells may be able to maintain redox homeostasis under exogenous ROS by adaptive response. Here, we show that parthenolide, a sesquiterpene lactone, selectively exhibits a radiosensitization effect on prostate cancer PC3 cells but not on normal prostate epithelial PrEC cells. Parthenolide causes oxidative stress in PC3 cells but not in PrEC cells, as determined by the oxidation of the ROS-sensitive probe H2DCFDA and intracellular reduced thiol and disulfide levels. In PC3 but not PrEC cells, parthenolide activates NADPH oxidase, leading to a decrease in the level of reduced thioredoxin, activation of phosphoinositide 3-kinase/Akt, and consequent FOXO3a phosphorylation, which results in the downregulation of FOXO3a targets antioxidant enzyme manganese superoxide dismutase and catalase. Importantly, when combined with radiation, parthenolide further increases ROS levels in PC3 cells whereas it decreases radiation-induced oxidative stress in PrEC cells, possibly by increasing reduced glutathione levels. Together, the results show that parthenolide selectively activates NADPH oxidase and mediates intense oxidative stress in prostate cancer cells by both increasing ROS generation and decreasing antioxidant defense capacity. The results support the concept of exploiting the intrinsic differences in the redox status of cancer cells and normal cells as targets for selective cancer killing. Cancer Res; 70(7); 2880–90
Data from Suppression of Tumor Growth and Metastasis by Simultaneously Blocking Vascular Endothelial Growth Factor (VEGF)–A and VEGF-C with a Receptor-Immunoglobulin Fusion Protein
Authors: Zhang Dapeng , Li Bohua , Shi Jingping , Zhao Lei , Zhang Xunming , Wang Chong , Hou Sheng , Qian Weizhu , Kou Geng , Wang Hao , Guo Yajun
Published: March 2024

Abstract
The major cause of cancer mortality is the metastatic spread of tumor cells that can occur via multiple routes, including the vascular system and the lymphatic system. In this study, we developed an IgG-like fusion protein molecule [vascular endothelial growth factor (VEGF) receptor 31–immunoglobulin (VEGFR31-Ig)] which could simultaneously bind the angiogenic growth factor VEGF-A and the lymphangiogenic growth factor VEGF-C. Importantly, VEGFR31-Ig exhibited VEGF-A–binding affinity similar to that of VEGFTrap, the most potent VEGF-A binder, and VEGF-C–binding affinity comparable with that of the soluble fusion protein VEGFR3-Ig (sVEGFR3). Pharmacokinetic analysis in mice showed that VEGFR31-Ig had improved pharmacokinetic properties compared with either VEGFTrap or sVEGFR3. In a highly metastatic human hepatocellular carcinoma (HCCLM3) model in severe combined immunodeficient mice, VEGFR31-Ig potently blocked both tumor angiogenesis and lymphangiogenesis, effectively inhibiting primary tumor growth and metastasis to lungs and lymph nodes. In contrast, VEGFTrap only suppressed primary tumor growth and metastasis to lungs by inhibiting tumor angiogenesis, whereas VEGFR3 was only effective in suppressing tumor metastasis to lymph nodes by blocking tumor lymphangiogenesis. Although a combination of VEGFTrap (25 mg/kg twice weekly) and sVEGFR3 (25 mg/kg twice weekly) can achieve the same therapeutic effect as VEGFR31-Ig (25 mg/kg twice weekly) in the HCCLM3 xenograft mouse model, developing two separate receptor-Ig fusion proteins for clinical use as combination therapy is impractical, mainly owing to regulatory hurdles and cost. Taken together, the VEGFR31-Ig fusion protein presented here has been suggested to have great potential for the treatment of metastatic cancer. Cancer Res; 70(6); 2495–503
Data from Phosphorylation of H2AX at Ser139 and a New Phosphorylation Site Ser16 by RSK2 Decreases H2AX Ubiquitination and Inhibits Cell Transformation
Authors: Zhu Feng , Zykova Tatyana A. , Peng Cong , Zhang Jishuai , Cho Yong-Yeon , Zheng Duo , Yao Ke , Ma Wei-Ya , Lau Andy T. Y. , Bode Ann M. , Dong Zigang
Published: March 2024

Abstract
Histone H2AX is a histone H2A variant that is ubiquitously expressed throughout the genome. It plays a key role in the cellular response to DNA damage and has been designated as the histone guardian of the genome. Histone H2AX deficiency decreases genomic stability and increases tumor susceptibility of normal cells and tissues. However, the role of histone H2AX phosphorylation in malignant transformation and cancer development is not totally clear. Herein, we found that ribosomal S6 kinase 2 (RSK2) directly phosphorylates histone H2AX at Ser139 and also at a newly discovered site, Ser16. Epidermal growth factor (EGF)–induced phosphorylation of histone H2AX at both sites was decreased in RSK2 knockout cells. Phosphorylated RSK2 and histone H2AX colocalized in the nucleus following EGF treatment, and the phosphorylation of histone H2AX by RSK2 enhanced the stability of histone H2AX and prevented cell transformation induced by EGF. RSK2 and DNA-PK, but not ATM or ATR, are required for EGF-induced phosphorylation of H2AX at Ser139; however, only RSK2 is required for phosphorylation of H2AX at Ser16. Phosphorylation of histone H3 was suppressed in cells expressing wild-type H2AX compared with H2AX knockout (H2AX−/−) cells. EGF-associated AP-1 transactivation activity was dramatically lower in H2AX−/− cells overexpressing wild-type H2AX than H2AX−/− cells expressing mutant H2AX-AA. Thus, the RSK2/H2AX signaling pathway negatively regulates the RSK2/histone H3 pathway and therefore maintains normal cell proliferation. Cancer Res; 71(2); 393–403. ©2011 AACR.
Data from Blockade of the Ubiquitin Protease UBP43 Destabilizes Transcription Factor PML/RARα and Inhibits the Growth of Acute Promyelocytic Leukemia
Authors: Guo Yongli , Dolinko Andrey V. , Chinyengetere Fadzai , Stanton Bruce , Bomberger Jennifer M. , Demidenko Eugene , Zhou Da-Cheng , Gallagher Robert , Ma Tian , Galimberti Fabrizio , Liu Xi , Sekula David , Freemantle Sarah , Dmitrovsky Ethan
Published: March 2024

Abstract
More effective treatments for acute promyelocytic leukemia (APL) are needed. APL cell treatment with all-trans-retinoic acid (RA) degrades the chimeric, dominant-negative–acting transcription factor promyelocytic leukemia gene (PML)/RARα, which is generated in APL by chromosomal translocation. The E1-like ubiquitin-activating enzyme (UBE1L) associates with interferon-stimulated gene ISG15 that binds and represses PML/RARα protein. Ubiquitin protease UBP43/USP18 removes ISG15 from conjugated proteins. In this study, we explored how RA regulates UBP43 expression and the effects of UBP43 on PML/RARα stability and APL growth, apoptosis, or differentiation. RA treatment induced UBE1L, ISG15, and UBP43 expression in RA-sensitive but not RA-resistant APL cells. Similar in vivo findings were obtained in a transgenic mouse model of transplantable APL, and in the RA response of leukemic cells harvested directly from APL patients. UBP43 knockdown repressed PML/RARα protein levels and inhibited RA-sensitive or RA-resistant cell growth by destabilizing the PML domain of PML/RARα. This inhibitory effect promoted apoptosis but did not affect the RA differentiation response in these APL cells. In contrast, elevation of UBP43 expression stabilized PML/RARα protein and inhibited apoptosis. Taken together, our findings define the ubiquitin protease UBP43 as a novel candidate drug target for APL treatment. Cancer Res; 70(23); 9875–85. ©2010 AACR.
Data from Molecular Mechanism of Chemoresistance by Astrocyte Elevated Gene-1
Authors: Yoo Byoung Kwon , Chen Dong , Su Zhao-zhong , Gredler Rachel , Yoo Jinsang , Shah Khalid , Fisher Paul B. , Sarkar Devanand
Published: March 2024

Abstract
Our recent findings show that astrocyte elevated gene-1 (AEG-1) is overexpressed in >90% of human hepatocellular carcinoma (HCC) samples, and AEG-1 plays a central role in regulating development and progression of HCC. In the present study, we elucidate a molecular mechanism of AEG-1–induced chemoresistance, an important characteristic of aggressive cancers. AEG-1 increases the expression of multidrug resistance gene 1 (MDR1) protein, resulting in increased efflux and decreased accumulation of doxorubicin, promoting doxorubicin resistance. Suppression of MDR1 by small interfering RNA or chemical reagents, or inhibition of AEG-1 or a combination of both genes, significantly increases in vitro sensitivity to doxorubicin. In nude mice xenograft studies, a lentivirus expressing AEG-1 short hairpin RNA, in combination with doxorubicin, profoundly inhibited growth of aggressive human HCC cells compared with either agent alone. We document that although AEG-1 does not affect MDR1 gene transcription, it facilitates association of MDR1 mRNA to polysomes, resulting in increased translation, and AEG-1 also inhibits ubiquitination and subsequent proteasome-mediated degradation of MDR1 protein. This study is the first documentation of a unique aspect of AEG-1 function (i.e., translational and posttranslational regulation of proteins). Inhibition of AEG-1 might provide a means of more effectively using chemotherapy to treat HCC, which displays inherent chemoresistance with aggressive pathology. Cancer Res; 70(8); 3249–58. ©2010 AACR.
Data from A High Molecular Weight Melanoma-Associated Antigen–Specific Chimeric Antigen Receptor Redirects Lymphocytes to Target Human Melanomas
Authors: Burns William R. , Zhao Yangbing , Frankel Timothy L. , Hinrichs Christian S. , Zheng Zhili , Xu Hui , Feldman Steven A. , Ferrone Soldano , Rosenberg Steven A. , Morgan Richard A.
Published: March 2024

Abstract
Immunotherapy, particularly the adoptive cell transfer (ACT) of tumor-infiltrating lymphocytes (TIL), is a very promising therapy for metastatic melanoma. Some patients unable to receive TIL have been successfully treated with autologous peripheral blood lymphocytes (PBL), genetically modified to express human leukocyte antigen (HLA) class I antigen–restricted, melanoma antigen–reactive T-cell receptors; however, substantial numbers of patients remain ineligible due to the lack of expression of the restricting HLA class I allele. We sought to overcome this limitation by designing a non–MHC-restricted, chimeric antigen receptor (CAR) targeting the high molecular weight melanoma-associated antigen (HMW-MAA), which is highly expressed on more than 90% of human melanomas but has a restricted distribution in normal tissues. HMW-MAA–specific CARs containing an antigen recognition domain based on variations of the HMW-MAA–specific monoclonal antibody 225.28S and a T-cell activation domain based on combinations of CD28, 4-1BB, and CD3ζ activation motifs were constructed within a retroviral vector to allow stable gene transfer into cells and their progeny. Following optimization of the HMW-MAA–specific CAR for expression and function in human PBL, these gene-modified T cells secreted cytokines, were cytolytic, and proliferated in response to HMW-MAA–expressing cell lines. Furthermore, the receptor functioned in both CD4+ and CD8+ cells, was non–MHC restricted, and reacted against explanted human melanomas. To evaluate this HMW-MAA–specific CAR in patients with metastatic melanoma, we developed a clinical-grade retroviral packaging line. This may represent a novel means to treat the majority of patients with advanced melanoma, most notably those unable to receive current ACT therapies. Cancer Res; 70(8); 3027–33. ©2010 AACR.
Data from Transforming Properties of 8p11-12 Amplified Genes in Human Breast Cancer
Authors: Yang Zeng-Quan , Liu Gang , Bollig-Fischer Aliccia , Giroux Craig N. , Ethier Stephen P.
Published: March 2024

Abstract
Amplification of the 8p11-12 region has been found in about 15% of human breast cancers and is associated with poor prognosis. Earlier, we used genomic analysis of copy number and gene expression to perform a detailed analysis of the 8p11-12 amplicon to identify candidate oncogenes in breast cancer. We identified 21 candidate genes and provided evidence that three genes, namely, LSM-1, TC-1, and BAG4, have transforming properties when overexpressed. In the present study, we systematically investigated the transforming properties of 13 newly identified 8p11-12 candidate oncogenes in vitro. WHSC1L1, DDHD2, and ERLIN2 were most potently transforming oncogenes based on the number of altered phenotypes expressed by the cells. WHSC1L1 contains a PWWP-domain that is a methyl-lysine recognition motif involved in histone code modification and epigenetic regulation of gene expression. Knockdown of WHSC1L1 in 8p11-12–amplified breast cancer cells resulted in profound loss of growth and survival of these cells. Further, we identified several WHSC1L1 target genes, one of which is iroquois homeobox 3 gene (IRX3), a member of the Iroquois homeobox transcription factor family. Cancer Res; 70(21); 8487–97. ©2010 AACR.
Data from Cooperation between Pik3ca and p53 Mutations in Mouse Mammary Tumor Formation
Authors: Adams Jessica R. , Xu Keli , Liu Jeff C. , Agamez Natalia M. Ruiz , Loch Amanda J. , Wong Ruth G. , Wang Wei , Wright Katherine L. , Lane Timothy F. , Zacksenhaus Eldad , Egan Sean E.
Published: March 2024

Abstract
PIK3CA, which codes for the p110α catalytic subunit of phosphatidylinositol 3-kinase, is one of the most frequently mutated genes in human breast cancer. Here, we describe a mouse model for PIK3CA-induced breast cancer by using the ROSA26 (R26) knock-in system, in which targeted Pik3ca alleles can be activated through transgenic expression of Cre recombinase. We mated Pik3caH1047R and Pik3cawt knock-in lines with MMTV-Cre transgenics, which express Cre in mammary epithelium. Starting at approximately 5 months of age, female R26-Pik3caH1047R;MMTV-Cre mice, but not control R26-Pik3cawt;MMTV-Cre mice, developed mammary tumors, as well as lymphoid and skin malignancies. R26-Pik3caH1047R;MMTV-Cre mammary tumors were typically either adenosquamous carcinoma or adenomyoepithelioma. As p53 is the most commonly mutated gene in breast cancer, we tested for genetic interaction between Pik3caH1047R and p53 loss-of-function mutations in R26-Pik3caH1047R;p53loxP/+;MMTV-Cre mice. This led to decreased survival of double-mutant animals, which developed lymphoma and mammary tumors with rapid kinetics. Mammary tumors that formed in p53loxP/+;MMTV-Cre conditional mutants were either poorly differentiated adenocarcinoma or spindle cell/EMT, whereas R26-Pik3caH1047R;p53loxP/+;MMTV-Cre mammary tumors were mostly adenosquamous carcinoma or spindle cell/EMT indicating that double-mutant mice develop a distinct spectrum of mammary tumors. Thus, an oncogenic variant of PIK3CA implicated in multiple human breast cancer subtypes can induce a very diverse spectrum of mammary tumors in mice. Furthermore, Pik3caH1047R shows cooperation with p53, which altered the specific tumors that formed. Thus, the two most frequently mutated genes in human breast cancer show cooperation in mammary tumor formation. Cancer Res; 71(7); 2706–17. ©2011 AACR.
Data from DLC1 Negatively Regulates Angiogenesis in a Paracrine Fashion
Authors: Shih Yi-Ping , Liao Yi-Chun , Lin Yuan , Lo Su Hao
Published: March 2024

Abstract
The Rho GTPase-activating protein DLC1 is a tumor suppressor that is often deleted in liver cancer and downregulated in other cancers. DLC1 regulates the actin cytoskeleton, cell shape, adhesion, migration, and proliferation through its Rho GTPase-activating protein activity and focal adhesion localization. In this study, we silenced DLC1 in nonmalignant prostate epithelial cells to explore its tumor suppression functions. Small hairpin RNA-mediated silencing of DLC1 was insufficient to promote more aggressive phenotypes associated with tumor cell growth. In contrast, DLC1 silencing promoted pro-angiogenic responses through vascular endothelial growth factor (VEGF) upregulation, accompanied by the accumulation of hypoxia-inducible factor 1α and its nuclear localization. Notably, modulation of VEGF expression by DLC1 was dependent on epidermal growth factor receptor–MAP/ERK kinase–hypoxia-inducible factor 1 signaling but on RhoA pathways. Clinically, VEGF upregulation is a highly significant event in prostate cancers in which DLC1 is downregulated. Thus, our results strongly suggest that loss of DLC1 may serve as a “second hit” in promoting angiogenesis in a paracrine fashion during tumorigenesis. Cancer Res; 70(21); 8270–5. ©2010 AACR.
Data from PrLZ Protects Prostate Cancer Cells from Apoptosis Induced by Androgen Deprivation via the Activation of Stat3/Bcl-2 Pathway
Authors: Zhang Dong , He Dalin , Xue Yan , Wang Ruoxiang , Wu Kaijie , Xie Hongjun , Zeng Jin , Wang Xinyang , Zhau Haiyen E. , Chung Leland W.K. , Chang Luke S. , Li Lei
Published: March 2024

Abstract
PrLZ/PC-1 is a newly identified, prostate-specific and androgen-inducible gene. Our previous study showed that PrLZ can enhance the proliferation and invasive capability of LNCaP cells, contributing to the development of prostate cancer. However, its potential role in androgen-independent processes remains elusive. In this study, we showed that PrLZ enhanced in vitro growth and colony formation of prostate cancer cells on androgen deprivation as well as tumorigenicity in castrated nude mice. In addition, PrLZ stabilized mitochondrial transmembrane potential, prevented release of cytochrome c from mitochondria to cytoplasm, and inhibited intrinsic apoptosis induced by androgen depletion. Mechanistically, PrLZ elevated the phosphorylation of Akt and Stat3 and upregulated Bcl-2 expression. Our data indicate that PrLZ protects prostate cancer cells from apoptosis and promotes tumor progression following androgen deprivation. In summary, we propose that PrLZ is a novel antiapoptotic gene that is specifically activated in prostate cancer cells escaping androgen deprivation may offer an appealing therapeutic target to prevent or treat advanced prostate malignancy. Cancer Res; 71(6); 2193–202. ©2011 AACR.
Data from Alternative Cyclin D1 Splice Forms Differentially Regulate the DNA Damage Response
Authors: Li Zhiping , Jiao Xuanmao , Wang Chenguang , Shirley L. Andrew , Elsaleh Hany , Dahl Olav , Wang Min , Soutoglou Evi , Knudsen Erik S. , Pestell Richard G.
Published: March 2024

Abstract
The DNA damage response (DDR) activates downstream pathways including cell cycle checkpoints. The cyclin D1 gene is overexpressed or amplified in many human cancers and is required for gastrointestinal, breast, and skin tumors in murine models. A common polymorphism in the human cyclin D1 gene is alternatively spliced, resulting in cyclin D1a and D1b proteins that differ in their carboxyl terminus. Cyclin D1 overexpression enhances DNA damage–induced apoptosis. The role of cyclin D1 and the alternative splice form in regulating the DDR is not well understood. Herein cyclin D1a overexpression enhanced the DDR as characterized by induction of γH2AX phosphorylation, the assembly of DNA repair foci, specific recruitment of DNA repair factors to chromatin, and G2-M arrest. Cyclin D1 deletion in fibroblasts or small interfering RNA–mediated reduction of endogenous cyclin D1 in colon cancer cells reduced the 5-fluorouracil–mediated DDR. Mechanistic studies showed that cyclin D1a, like DNA repair factors, elicited the DDR when stably associated with chromatin. Cancer Res; 70(21); 8802–11. ©2010 AACR.