bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Reactive Oxygen Species Regulate Angiogenesis and Tumor Growth through Vascular Endothelial Growth Factor
Authors: Xia Chang , Meng Qiao , Liu Ling-Zhi , Rojanasakul Yongyut , Wang Xin-Ru , Jiang Bing-Hua
Published: March 2024

Abstract
Reactive oxygen species (ROS) are associated with multiple cellular functions such as cell proliferation, differentiation, and apoptosis. However, the direct roles of endogenous ROS production still remain to be elucidated. In this study, we found that high levels of ROS were spontaneously produced by ovarian and prostate cancer cells. This elevated ROS production was inhibited by NADPH oxidase inhibitor diphenylene iodonium (DPI) and mitochondria electron chain inhibitor rotenone in the cells. To further analyze the source of ROS production, we found that ovarian cancer cells have much higher expression of NOX4 NADPH oxidase, and that specific inhibition of NADPH oxidase subunit p47phox diminished ROS production. To analyze the functional relevance of ROS production, we showed that ROS regulated hypoxia-inducible factor 1 (HIF-1) and vascular endothelial growth factor (VEGF) expression in ovarian cancer cells. Elevated levels of endogenous ROS were required for inducing angiogenesis and tumor growth. NOX4 knockdown in ovarian cancer cells decreased the levels of VEGF and HIF-1α and tumor angiogenesis. This study suggests a new mechanism of higher ROS production in ovarian cancer cells and provides strong evidence that endogenous ROS play an important role for cancer cells to induce angiogenesis and tumor growth. This information may be useful to understand the new mechanism of cancer cells in inducing tumorigenesis and to develop new therapeutic strategy by targeting ROS signaling in human cancer in the future. [Cancer Res 2007;67(22):10823–30]
Data from Cells Deficient in the FANC/BRCA Pathway Are Hypersensitive to Plasma Levels of Formaldehyde
Authors: Ridpath John R. , Nakamura Ayumi , Tano Keizo , Luke April M. , Sonoda Eiichiro , Arakawa Hiroshi , Buerstedde Jean-Marie , Gillespie David A.F. , Sale Julian E. , Yamazoe Mitsuyoshi , Bishop Douglas K. , Takata Minoru , Takeda Shunichi , Watanabe Masami , Swenberg James A. , Nakamura Jun
Published: March 2024

Abstract
Formaldehyde is an aliphatic monoaldehyde and is a highly reactive environmental human carcinogen. Whereas humans are continuously exposed to exogenous formaldehyde, this reactive aldehyde is a naturally occurring biological compound that is present in human plasma at concentrations ranging from 13 to 97 μmol/L. It has been well documented that DNA-protein crosslinks (DPC) likely play an important role with regard to the genotoxicity and carcinogenicity of formaldehyde. However, little is known about which DNA damage response pathways are essential for cells to counteract formaldehyde. In the present study, we first assessed the DNA damage response to plasma levels of formaldehyde using chicken DT40 cells with targeted mutations in various DNA repair genes. Here, we show that the hypersensitivity to formaldehyde is detected in DT40 mutants deficient in the BRCA/FANC pathway, homologous recombination, or translesion DNA synthesis. In addition, FANCD2-deficient DT40 cells are hypersensitive to acetaldehyde, but not to acrolein, crotonaldehyde, glyoxal, and methylglyoxal. Human cells deficient in FANCC and FANCG are also hypersensitive to plasma levels of formaldehyde. These results indicate that the BRCA/FANC pathway is essential to counteract DPCs caused by aliphatic monoaldehydes. Based on the results obtained in the present study, we are currently proposing that endogenous formaldehyde might have an effect on highly proliferating cells, such as bone marrow cells, as well as an etiology of cancer in Fanconi anemia patients. [Cancer Res 2007;67(23):11117–22]
Data from Semaphorin SEMA3F Affects Multiple Signaling Pathways in Lung Cancer Cells
Authors: Potiron Vincent A. , Sharma Girish , Nasarre Patrick , Clarhaut Jonathan A. , Augustin Hellmut G. , Gemmill Robert M. , Roche Joëlle , Drabkin Harry A.
Published: March 2024

Abstract
Loss of SEMA3F occurs frequently in lung cancer and correlates with advanced stage of disease. We previously reported that SEMA3F blocked tumor formation by H157 lung cancer cells in a rat orthotopic model. This was associated with loss of activated αVβ3 integrin, impaired cell adhesion to extracellular matrix components, and down-regulation of phospho-extracellular signal-regulated kinase 1/2 (ERK1/2). These results suggested that SEMA3F might interfere with integrin outside-in signaling. In the present report, we found that SEMA3F decreased adhesion to vitronectin, whereas integrin-linked kinase (ILK) kinase activity was down-regulated in SEMA3F-expressing H157 cells. Exposure to SEMA3F-conditioned medium led to diminution of phospho-ERK1/2 in four of eight lung cancer cell lines, and ILK silencing by small interfering RNA led to similar loss of phospho-ERK1/2 in H157 cells. Moreover, SEMA3F expression (with constitutive and inducible systems) also reduced AKT and signal transducer and activator of transcription 3 (STAT3) phosphorylation independently of ILK-ERK1/2. These signaling changes extended downstream to hypoxia-inducible factor-1α (HIF-1α) protein and vascular endothelial growth factor (VEGF) mRNA levels, which were both reduced in three of four SEMA3F-transfected cell lines. Mechanistically, the effects on HIF-1α were consistent with inhibition of its AKT-driven protein translation initiation, with no effect on HIF-1α mRNA level or protein degradation. Furthermore, when H157 cells were injected s.c. in nude mice, tumors derived from SEMA3F-expressing cells showed lower microvessel density and tumor growth. These results show that SEMA3F negatively affects ILK-ERK1/2 and AKT-STAT3 signaling, along with inhibition of HIF-1α and VEGF. These changes would be anticipated to contribute significantly to the observed antitumor activity of SEMA3F. [Cancer Res 2007;67(18):8708–15]
Data from Gain of Oncogenic Function of p53 Mutants Induces Invasive Phenotypes in Human Breast Cancer Cells by Silencing CCN5/WISP-2
Authors: Dhar Gopal , Banerjee Snigdha , Dhar Kakali , Tawfik Ossama , Mayo Matthew S. , VanVeldhuizen Peter J. , Banerjee Sushanta K.
Published: March 2024

Abstract
CCN5/WISP-2 is overexpressed in noninvasive breast cancer cells and tissue samples, whereas its expression is minimal or undetected in invasive conditions. CCN5/WISP-2 has been considered as an antiinvasive gene because CCN5/WISP-2 silencing augments the invasive phenotypes in vitro. However, the mechanism of silencing of CCN5 during the progression of the disease has been elusive. Because p53 mutations are associated with breast cancer progression and have been shown to correlate inversely with CCN5/WISP-2 expression in other cancer cell types, the objective of this study was to explore whether p53 mutants suppress CCN5 expression in breast tumor cells resulting in the progression of this disease. We found CCN5 expression is inversely correlated with the mutational activation of p53 in human breast tumor cells. The ectopic expression of p53 mutants in ER-positive noninvasive breast tumor cells silenced the CCN5/WISP-2 expression and enhanced invasive phenotypes, including the induction of morphologic changes from the epithelial-to-mesenchymal type along with the alterations of hallmark proteins of these cell types and an augmentation of the migration of these cells. The suppression of CCN5 by the p53 mutants can be nullified by estrogen signaling in these cells through the transcriptional activation of the CCN5 gene. Moreover, the invasive changes can be imitated by blocking the CCN5/WISP-2 expression through RNA interference or can be reversed by the addition of CCN5/WISP-2 recombinant protein in the culture. Thus, these studies suggest that CCN5 inactivation could be an essential molecular event for p53 mutant–induced invasive phenotypes. [Cancer Res 2008;68(12):4580–7]
Data from FBXW7/hCDC4 Is a General Tumor Suppressor in Human Cancer
Authors: Akhoondi Shahab , Sun Dahui , von der Lehr Natalie , Apostolidou Sophia , Klotz Kathleen , Maljukova Alena , Cepeda Diana , Fiegl Heidi , Dofou Dimitra , Marth Christian , Mueller-Holzner Elisabeth , Corcoran Martin , Dagnell Markus , Nejad Sepideh Zabihi , Nayer Babak Noori , Zali Mohammad Reza , Hansson Johan , Egyhazi Susanne , Petersson Fredrik , Sangfelt Per , Nordgren Hans , Grander Dan , Reed Steven I. , Widschwendter Martin , Sangfelt Olle , Spruck Charles
Published: March 2024

Abstract
The ubiquitin-proteasome system is a major regulatory pathway of protein degradation and plays an important role in cellular division. Fbxw7 (or hCdc4), a member of the F-box family of proteins, which are substrate recognition components of the multisubunit ubiquitin ligase SCF (Skp1-Cdc53/Cullin-F-box-protein), has been shown to mediate the ubiquitin-dependent proteolysis of several oncoproteins including cyclin E1, c-Myc, c-Jun, and Notch. The oncogenic potential of Fbxw7 substrates, frequent allelic loss in human cancers, and demonstration that mutation of FBXW7 cooperates with p53 in mouse tumorigenesis have suggested that Fbxw7 could function as a tumor suppressor in human cancer. Here, we carry out an extensive genetic screen of primary tumors to evaluate the role of FBXW7 as a tumor suppressor in human tumorigenesis. Our results indicate that FBXW7 is inactivated by mutation in diverse human cancer types with an overall mutation frequency of ∼6%. The highest mutation frequencies were found in tumors of the bile duct (cholangiocarcinomas, 35%), blood (T-cell acute lymphocytic leukemia, 31%), endometrium (9%), colon (9%), and stomach (6%). Approximately 43% of all mutations occur at two mutational “hotspots,” which alter Arg residues (Arg465 and Arg479) that are critical for substrate recognition. Furthermore, we show that Fbxw7Arg465 hotspot mutant can abrogate wild-type Fbxw7 function through a dominant negative mechanism. Our study is the first comprehensive screen of FBXW7 mutations in various human malignancies and shows that FBXW7 is a general tumor suppressor in human cancer. [Cancer Res 2007;67(19):9006–12]
Data from Genetic Determinants of Mitochondrial Response to Arsenic in Yeast Saccharomyces cerevisiae
Authors: Vujcic Marija , Shroff Meghna , Singh Keshav K.
Published: March 2024

Abstract
We have used yeast Saccharomyces cerevisiae as a tool to identify the importance of mitochondrial processes involved in arsenic-induced carcinogenicity in humans. We screened 466 single-gene knockout strains of yeast S. cerevisiae known to be involved in biogenesis of mitochondria for sodium arsenite (AsIII) and sodium arsenate (AsV) sensitivity. We identified 72 arsenite-sensitive and 81 arsenate-sensitive mutants. We categorized the identified mutants based on the various mitochondrial processes, including nucleic acid metabolism, oxidative phosphorylation, protein synthesis, and vacuolar acidification. We have identified 65 human orthologues to proteins involved in arsenite sensitivity and 3 human orthologues to arsenite resistance. Furthermore, 23 human orthologues to arsenate sensitivity and 20 human orthologues to arsenate-resistant proteins, including MSH3, COX10, GCSH, PPOX, and MTHFD1, were also identified. Using PathwayAssist software, we did cellular network analysis between identified mitochondrial proteins. Three types of interactions, (a) protein-protein interactions, (b) common transcriptional regulators, and (c) common target genes, were identified. We found that RTG (retrograde) genes involved in mitochondria-to-nucleus signaling regulate both arsenite sensitivity and resistance. Furthermore, our study revealed that ABF1, a multifunctional transcriptional factor, regulates genes involved in both arsenite and arsenate sensitivity and resistance. However, REB1 and RAP1 transcriptional regulators were common to only arsenate- and arsenite-sensitive genes, respectively. These studies indicate that multiple pathways involved in mitochondrial biogenesis protect yeast S. cerevisiae from arsenic-induced toxicity. Together, our studies suggest that evolutionary conserved mitochondrial networks identified in yeast S. cerevisiae must play an important role in arsenic-induced carcinogenesis in humans. [Cancer Res 2007;67(20):9740–9]
Data from Medulloblastomas Derived from Cxcr6 Mutant Mice Respond to Treatment with a Smoothened Inhibitor
Authors: Sasai Ken , Romer Justyna T. , Kimura Hiromichi , Eberhart Derek E. , Rice Dennis S. , Curran Tom
Published: March 2024

Abstract
The sonic hedgehog (Shh) pathway is activated in ∼30% of human medulloblastoma resulting in increased expression of downstream target genes. In about half of these cases, this has been shown to be a consequence of mutations in regulatory genes within the pathway, including Ptc1, Smo, and Sufu. However, for some tumors, no mutations have been detected in known pathway genes. This suggests that either mutations in other genes promote tumorigenesis or that epigenetic alterations increase pathway activity in these tumors. Here, we report that 3% to 4% of mice lacking either one or both functional copies of Cxcr6 develop medulloblastoma. Although CXCR6 is not known to be involved in Shh signaling, tumors derived from Cxcr6 mutant mice expressed Shh pathway target genes including Gli1, Gli2, Ptc2, and Sfrp1, indicating elevated pathway activity. Interestingly, the level of Ptc1 expression was decreased in tumor cells although two normal copies of Ptc1 were retained. This implies that reduced CXCR6 function leads to suppression of Ptc1 thereby increasing Smoothened function and promoting tumorigenesis. We used a direct transplant model to test the sensitivity of medulloblastoma arising in Cxcr6 mutant mice to a small-molecule inhibitor of Smoothened (HhAntag). We found that transplanted tumors were dramatically inhibited in mice treated for only 4 days with HhAntag. These findings suggest that HhAntag may be effective against tumors lacking mutations in known Shh pathway genes. [Cancer Res 2007;67(8):3871–7]
Data from Deregulated CDC25A Expression Promotes Mammary Tumorigenesis with Genomic Instability
Authors: Ray Dipankar , Terao Yasuhisa , Fuhrken Peter G. , Ma Zhi-Qing , DeMayo Francesco J. , Christov Konstantin , Heerema Nyla A. , Franks Roberta , Tsai Sophia Y. , Papoutsakis Eleftherios T. , Kiyokawa Hiroaki
Published: March 2024

Abstract
Checkpoint pathways help cells maintain genomic integrity, delaying cell cycle progression in response to various risks of fidelity, such as genotoxic stresses, compromised DNA replication, and impaired spindle control. Cancer cells frequently exhibit genomic instability, and recent studies showed that checkpoint pathways are likely to serve as a tumor-suppressive barrier in vivo. The cell cycle–promoting phosphatase CDC25A is an activator of cyclin-dependent kinases and one of the downstream targets for the CHK1-mediated checkpoint pathway. Whereas CDC25A overexpression is observed in various human cancer tissues, it has not been determined whether deregulated CDC25A expression triggers or promotes tumorigenesis in vivo. Here, we show that transgenic expression of CDC25A cooperates markedly with oncogenic ras or neu in murine mammary tumorigenesis. MMTV-CDC25A transgenic mice exhibit alveolar hyperplasia in the mammary tissue but do not develop spontaneous mammary tumors. The MMTV-CDC25A transgene markedly shortens latency of tumorigenesis in MMTV-ras mice. The MMTV-CDC25A transgene also accelerates tumor growth in MMTV-neu mice with apparent cell cycle miscoordination. CDC25A-overexpressing tumors, which invade more aggressively, exhibit various chromosomal aberrations on fragile regions, including the mouse counterpart of human 1p31-36, according to array-based comparative genomic hybridization and karyotyping. The chromosomal aberrations account for substantial changes in gene expression profile rendered by transgenic expression of CDC25A, including down-regulation of Trp73. These data indicate that deregulated control of cellular CDC25A levels leads to in vivo genomic instability, which cooperates with the neu-ras oncogenic pathway in mammary tumorigenesis. [Cancer Res 2007;67(3):984–91]
Data from Distinctive MicroRNA Profiles Relating to Patient Survival in Esophageal Squamous Cell Carcinoma
Authors: Guo Yong , Chen Zhaoli , Zhang Liang , Zhou Fang , Shi Susheng , Feng Xiaoli , Li Baozhong , Meng Xin , Ma Xi , Luo Mingyong , Shao Kang , Li Ning , Qiu Bin , Mitchelson Keith , Cheng Jing , He Jie
Published: March 2024

Abstract
Esophageal cancer is the sixth leading cause of death from cancer and one of the least studied cancers worldwide. The global microRNA expression profile of esophageal cancer has not been reported previously. Here, for the first time, we have investigated expressed microRNAs in cryopreserved esophageal cancer tissues using advanced microRNA microarray techniques. Our microarray analyses identified seven microRNAs that could distinguish malignant esophageal cancer lesions from adjacent normal tissues. Some microRNAs could be correlated with the different clinicopathologic classifications. High expression of hsa-miR-103/107 correlated with poor survival by univariate analysis as well as by multivariate analysis. These results indicate that microRNA expression profiles are important diagnostic and prognostic markers of esophageal cancer, which might be analyzed simply using economical approaches such as reverse transcription-PCR. [Cancer Res 2008;68(1):26–33]
Data from P21-Activated Protein Kinase Is Overexpressed in Hepatocellular Carcinoma and Enhances Cancer Metastasis Involving c-Jun NH2-Terminal Kinase Activation and Paxillin Phosphorylation
Authors: Ching Yick-Pang , Leong Veronica Y.L. , Lee Man-Fong , Xu Hai-Tao , Jin Dong-Yan , Ng Irene Oi-Lin
Published: March 2024

Abstract
Hepatocellular carcinoma (HCC) is one of the major malignancies in the world. The prognosis of HCC is poor, due to frequent intrahepatic metastasis and tumor recurrence. P21-activated protein kinase (Pak1), a main downstream effector of small Rho GTPases, Rac1 and Cdc42, plays an important role in the regulation of cell morphogenesis, motility, mitosis, and angiogenesis. Here, we show that Pak1 gene was overexpressed in human HCCs. Overexpression of Pak1 in human HCCs was associated with more aggressive tumor behavior in terms of more metastatic phenotype and more advanced tumor stages. In addition, HCC cell line stably expressing Pak1 displayed increased cell motility rates and, conversely, knockdown of endogenous Pak1 expression by small interfering RNA reduced the migration rates of HCC cells. In an established metastatic HCC cell line, we found that Pak1 was overexpressed compared with its primary HCC cell line and this overexpression was associated with higher cell motility. Importantly, we found that c-Jun NH2-terminal kinase (JNK) was activated in HCC cell lines overexpressing Pak1. Inhibition of the JNK activity by chemical inhibitor significantly reduced the migration rates of HCC cells via attenuation of paxillin phosphorylation at Ser178. In conclusion, our results document that Pak1 is overexpressed in HCCs and plays an important role in the metastasis of HCC. The mechanism by which Pak1 induces cancer metastasis may involve activation of JNK and phosphorylation of paxillin. [Cancer Res 2007;67(8):3601–8]
Data from Phosphatidylcholine-Specific Phospholipase C Activation in Epithelial Ovarian Cancer Cells
Authors: Spadaro Francesca , Ramoni Carlo , Mezzanzanica Delia , Miotti Silvia , Alberti Paola , Cecchetti Serena , Iorio Egidio , Dolo Vincenza , Canevari Silvana , Podo Franca
Published: March 2024

Abstract
Elucidation of the mechanisms responsible for aberrant phosphatidylcholine (PC) metabolism in cancer cells may allow identification of novel biomarkers of tumor progression and design of new targeted anticancer therapies. We recently reported up-regulation of PC-specific phospholipases in epithelial ovarian cancer cells (EOC) compared with nontumoral (normal or immortalized) counterparts (EONT). In the present study, we focused, in the same cell systems, on levels, subcellular localization, and activity of PC-specific phospholipase C (PC-PLC), for which a key role in cell proliferation, differentiation, and apoptosis has been shown in several mammalian cells. A 66-kDa PC-PLC isoform, detected in nuclear and cytoplasmic compartments of both EOC and EONT cells, accumulated on the external plasma membrane of cancer cells only, where it colocalized with β1 integrin, in nonraft membrane domains. PC-PLC activity was 3-fold higher in total cell lysates and 5-fold higher in membrane-enriched fractions of EOC compared with EONT cells. Serum deprivation induced in EOC, but not in EONT, cells a 3-fold decrease in PC-PLC activity, associated with a 40% drop in S-phase fraction. The recovery of both variables to their original levels in serum-restimulated (or lysophosphatidic acid–restimulated) EOC cells was strongly delayed, for at least 24 h, in the presence of the PC-PLC inhibitor tricyclodecan-9-yl-potassium xanthate (D609). The S-phase of serum-restimulated EONT cells was not sensitive to D609. These findings warrant further investigations on the role of PC-PLC and on the effects of its inhibition on the pathways responsible for constitutive EOC cell stimulation and cell proliferation. [Cancer Res 2008;68(16):6541–9]
Data from Identification and Characterization of Genetic Variation in the Folylpolyglutamate Synthase Gene
Authors: Leil Tarek A. , Endo Chiaki , Adjei Araba A. , Dy Grace K. , Salavaggione Oreste E. , Reid Joel R. , Ames Matthew M. , Adjei Alex A.
Published: March 2024

Abstract
Folylpolyglutamate synthase (FPGS) catalyzes the polyglutamation of folic acid, methotrexate, and pemetrexed to produce highly active metabolites. To characterize genetic variation in the FPGS gene, FPGS, have resequenced the gene in four different ethnic populations. Thirty-four single nucleotide polymorphisms were identified including five nonsynonymous coding single nucleotide polymorphisms that altered the FPGS protein sequence: F13L and V22I polymorphisms in the mitochondrial isoform of FPGS, and R466/424C, A489/447V, and S499/457F polymorphisms, which exist in both the mitochondrial and cytosolic isoforms. When expressed in AuxB1 cells, the A447V cytosolic variant was functionally similar to the wild-type cytosolic (WT Cyt) allozyme, whereas the R424C and S457F cytosolic variants were reduced by ∼2-fold in protein expression compared with WT Cyt (P < 0.01). The intrinsic clearance of glutamate was reduced by 12.3-fold (R424C, P < 0.01) and 6.2-fold (S457F, P < 0.01), whereas the intrinsic clearance of methotrexate was reduced by 4.2-fold (R424C, P < 0.05) and 5.4-fold (S457F, P < 0.05) in these two cytosolic variants when compared with the WT Cyt isoform. Additionally, the in vitro enzyme velocity at saturating pemetrexed concentrations was reduced by 1.6-fold (R424C, P < 0.05) and 2.6-fold (S457F, P < 0.01) compared with WT Cyt. AuxB1 cells harboring these same cytosolic variant allozymes displayed significant increases in the EC50 for folic acid and in the IC50 values for both methotrexate and pemetrexed relative to the WT Cyt form of FPGS. These observations suggest that genetic variations in FPGS may alter the efficacy of antifolate therapy in cancer patients. [Cancer Res 2007;67(18):8772–82]
Data from Live Attenuated Listeria Monocytogenes Effectively Treats Hepatic Colorectal Cancer Metastases and Is Strongly Enhanced by Depletion of Regulatory T Cells
Authors: Yoshimura Kiyoshi , Laird Lindsay S. , Chia Christina Y. , Meckel Kristen F. , Slansky Jill E. , Thompson John M. , Jain Ajay , Pardoll Drew M. , Schulick Richard D.
Published: March 2024

Abstract
The liver represents a major and frequently sole site of metastases for many types of cancer, particularly gastrointestinal cancers. We showed previously that coadministration of an engineered hepatic-targeting Listeria monocytogenes (LM) with a cancer vaccine enhanced the antitumor effect of vaccine-induced T cells selectively against hepatic metastases. Here, we show that administration of multiple doses of LM, in the absence of vaccine, generates therapeutic responses against hepatic metastases. LM treatment of mice bearing hepatic metastases induced tumor-specific CD8+ T-cell responses that were enhanced by depletion of regulatory T (Treg) cells by either anti-CD25 or cyclophosphamide treatment. Antitumor activity of LM further depended on natural killer (NK) cell activation but was inhibited by presence of a subset of NK T cells. These results show the utility of LM in the treatment of hepatic metastases even in the absence of vaccine administration and further suggest that blockade of Treg cells and NK T cells will enhance antitumor activity. [Cancer Res 2007;67(20):10058–66]
Data from Fhit-Deficient Hematopoietic Stem Cells Survive Hydroquinone Exposure Carrying Precancerous Changes
Authors: Ishii Hideshi , Mimori Koshi , Ishikawa Kazuhiro , Okumura Hiroshi , Pichiorri Flavia , Druck Teresa , Inoue Hiroshi , Vecchione Andrea , Saito Toshiyuki , Mori Masaki , Huebner Kay
Published: March 2024

Abstract
The fragile FHIT gene is among the first targets of DNA damage in preneoplastic lesions, and recent studies have shown that Fhit protein is involved in surveillance of genome integrity and checkpoint response after genotoxin exposure. We now find that Fhit-deficient hematopoietic cells, exposed to the genotoxin hydroquinone, are resistant to the suppression of stem cell in vitro colony formation observed with wild-type (Wt) hematopoietic cells. In vivo–transplanted, hydroquinone-exposed, Fhit-deficient bone marrow cells also escaped the bone marrow suppression exhibited by Wt-transplanted bone marrow. Comparative immunohistochemical analyses of bone marrow transplants showed relative absence of Bax in Fhit-deficient bone marrow, suggesting insensitivity to apoptosis; assessment of DNA damage showed that occurrence of the oxidized base 8-hydroxyguanosine, a marker of DNA damage, was also reduced in Fhit-deficient bone marrow, as was production of intracellular reactive oxygen species. Treatment with the antioxidant N-acetyl-l-cysteine relieved hydroquinone-induced suppression of colony formation by Wt hematopoietic cells, suggesting that the decreased oxidative damage to Fhit-deficient cells, relative to Wt hematopoietic cells, accounts for the survival advantage of Fhit-deficient bone marrow. Homology-dependent recombination repair predominated in Fhit-deficient cells, although not error-free repair, as indicated by a higher incidence of 6-thioguanine–resistant colonies. Tissues of hydroquinone-exposed Fhit-deficient bone marrow–transplanted mice exhibited preneoplastic alterations, including accumulation of histone H2AX-positive DNA damage. The results indicate that reduced oxidative stress, coupled with efficient but not error-free DNA damage repair, allows unscheduled long-term survival of genotoxin-exposed Fhit-deficient hematopoietic stem cells carrying deleterious mutations. [Cancer Res 2008;68(10):3662–70]
Data from A Smac Mimetic Rescue Screen Reveals Roles for Inhibitor of Apoptosis Proteins in Tumor Necrosis Factor-α Signaling
Authors: Gaither Alex , Porter Dale , Yao Yao , Borawski Jason , Yang Guang , Donovan Jerry , Sage David , Slisz Joanna , Tran Mary , Straub Christopher , Ramsey Tim , Iourgenko Vadim , Huang Alan , Chen Yan , Schlegel Robert , Labow Mark , Fawell Stephen , Sellers William R. , Zawel Leigh
Published: March 2024

Abstract
Smac mimetic compounds targeting the inhibitor of apoptosis proteins (IAP) baculoviral IAP repeat-3 domain are presumed to reduce the threshold for apoptotic cell death by alleviating caspase-9 repression. We explored this tenet in an unbiased manner by searching for small interfering RNAs that are able to confer resistance to the Smac mimetic compound LBW242. Among the screening hits were multiple components of the tumor necrosis factor α (TNFα) signaling pathway as well as X-linked inhibitor of apoptosis (XIAP) itself. Here, we show that in a subset of highly sensitive tumor cell lines, activity of LBW242 is dependent on TNFα signaling. Mechanistic studies indicate that in this context, XIAP is a positive modulator of TNFα induction whereas cellular inhibitor of apoptosis protein 1 negatively regulates TNFα-mediated apoptosis. [Cancer Res 2007;67(24):11493–8]
Data from Human T-Cell Leukemia Virus I Tax Protein Sensitizes p53-Mutant Cells to DNA Damage
Authors: Mihaylova Valia T. , Green Allison M. , Khurgel Moshe , Semmes Oliver J. , Kupfer Gary M.
Published: March 2024

Abstract
Mutations in p53 are a common cause of resistance of cancers to standard chemotherapy and, thus, treatment failure. Reports have shown that Tax, a human T-cell leukemia virus type I encoded protein that has been associated with genomic instability and perturbation of transcription and cell cycle, sensitizes HeLa cells to UV treatment. The extent to which Tax can sensitize cells and the mechanism by which it exerts its effect are unknown. In this study, we show that Tax sensitizes p53-mutant cells to a broad range of DNA-damaging agents, including mitomycin C, a bifunctional alkylator, etoposide, a topoisomerase II drug, and UV light, but not ionizing radiation, a double-strand break agent, or vinblastine, a tubulin poison. Tax caused hypersensitivity in all p53-deleted cell lines and several, but not all, mutant-expressed p53–containing cell lines, while unexpectedly being protective in p53 wild-type (wt) cells. The effect observed in p53-deleted lines could be reversed for this by transfection of wt p53. We also show that Tax activates a p53-independent proapoptotic program through decreased expression of the retinoblastoma protein and subsequent increased E2F1 expression. The expression of several proapoptotic proteins was also induced by Tax, including Puma and Noxa, culminating in a substantial increase in Bax dimerization. Our results show that Tax can sensitize p53-mutant cells to DNA damage while protecting p53 wt cells, a side benefit that might result in reduced toxicity in normal cells. Such studies hold the promise of a novel adjunctive therapy that could make cancer chemotherapy more effective. [Cancer Res 2008;68(12):4843–52]
Data from Paxillin Is a Target for Somatic Mutations in Lung Cancer: Implications for Cell Growth and Invasion
Authors: Jagadeeswaran Ramasamy , Surawska Hanna , Krishnaswamy Soundararajan , Janamanchi Varalakshmi , Mackinnon A. Craig , Seiwert Tanguy Y. , Loganathan Sivakumar , Kanteti Rajani , Reichman Trevor , Nallasura Vidya , Schwartz Stuart , Faoro Leonardo , Wang Yi-Ching , Girard Luc , Tretiakova Maria S. , Ahmed Salman , Zumba Osvaldo , Soulii Lioubov , Bindokas Vytas P. , Szeto Livia L. , Gordon Gavin J. , Bueno Raphael , Sugarbaker David , Lingen Mark W. , Sattler Martin , Krausz Thomas , Vigneswaran Wickii , Natarajan Viswanathan , Minna John , Vokes Everett E. , Ferguson Mark K. , Husain Aliya N. , Salgia Ravi
Published: March 2024

Abstract
Lung cancer is characterized by abnormal cell growth and invasion, and the actin cytoskeleton plays a major role in these processes. The focal adhesion protein paxillin is a target of a number of oncogenes involved in key signal transduction and important in cell motility and migration. In lung cancer tissues, we have found that paxillin was highly expressed (compared with normal lung), amplified (12.1%, 8 of 66) and correlated with increased MET and epidermal growth factor receptor (EGFR) gene copy numbers, or mutated (somatic mutation rate of 9.4%, 18 of 191). Paxillin mutations (19 of 21) were clustered between LD motifs 1 and 2 and the LIM domains. The most frequent point mutation (A127T) enhanced lung cancer cell growth, colony formation, focal adhesion formation, and colocalized with Bcl-2 in vitro. Gene silencing from RNA interference of mutant paxillin led to reduction of cell viability. A murine in vivo xenograft model of A127T paxillin showed an increase in tumor growth, cell proliferation, and invasion. These results establish an important role for paxillin in lung cancer. [Cancer Res 2007;68(1):132–42]
Data from Targeting the BAF57 SWI/SNF Subunit in Prostate Cancer: A Novel Platform to Control Androgen Receptor Activity
Authors: Link Kevin A. , Balasubramaniam Sucharitha , Sharma Ankur , Comstock Clay E.S. , Godoy-Tundidor Sonia , Powers Nathan , Cao Khanh H. , Haelens Annemie , Claessens Frank , Revelo Monica P. , Knudsen Karen E.
Published: March 2024

Abstract
The androgen receptor (AR) is critical for disseminated prostate cancer proliferation and survival. AR activity is targeted either through prevention of ligand synthesis or through the use of antagonists that bind the COOH-terminal ligand-binding domain. Although initially effective, treatment fails due to restored AR activity in the presence of therapeutics. Thus, new means must be developed to target AR activity. The SWI/SNF chromatin remodeling complex is critical for AR transcriptional activity, and the BAF57 SWI/SNF subunit facilitates direct interaction with the receptor. Although selected SWI/SNF subunit expression is reduced in prostate cancer, we show that BAF57 is retained in human disease and is elevated in a subset of tumors. Functional analyses showed that BAF57 contributes uniquely to androgen-mediated stimulation of transcription without compromising the effectiveness of AR antagonists. Subsequent studies revealed that BAF57 is recruited to the AR DNA-binding domain/hinge region, which occurs concomitant with receptor activation. These data provided the basis for a novel inhibitor derived from BAF57 [BAF57 inhibitory peptide (BIPep)], which blocked AR residence on chromatin and resultant AR-dependent gene activation. Importantly, BIPep expression was sufficient to inhibit androgen-dependent prostate cancer cell proliferation in AR-positive cells. In summary, these data identify blockade of AR-BAF57 interaction as a novel means to target agonist-induced AR function in prostate cancer, and provide the first evidence that abrogation of SWI/SNF function can be developed as a point of therapeutic intervention in prostate cancer. [Cancer Res 2008;68(12):4551–8]
Data from Batracylin (NSC 320846), a Dual Inhibitor of DNA Topoisomerases I and II Induces Histone γ-H2AX as a Biomarker of DNA Damage
Authors: Rao V. Ashutosh , Agama Keli , Holbeck Susan , Pommier Yves
Published: March 2024

Abstract
Batracylin (8-aminoisoindolo [1,2-b]quinazolin-10(12H)-one; NSC320846) is an investigational clinical anticancer agent. Previous animal studies showed activity against solid tumors and Adriamycin-resistant leukemia. We initially sought to test the proposed Top2-mediated DNA cleavage activity of batracylin and identify potential biomarkers for activity. COMPARE analysis in the NCI-60 cell lines showed batracylin activity to be most closely related to the class of Top2 inhibitors. The 50% growth inhibition (GI50) value for batracylin in HT29 colon carcinoma cells was 10 μmol/L. DNA-protein cross-links, consistent with Top2 targeting, were measured by alkaline elution. DNA single-strand breaks were also detected and found to be protein associated. However, only a weak induction of DNA double-strand breaks was observed. Because batracylin induced almost exclusively DNA single-strand breaks, we tested batracylin as a Top1 inhibitor. Batracylin exhibited both Top1- and Top2α/β-mediated DNA cleavage in vitro and in cells. The phosphorylation of histone (γ-H2AX) was tested to measure the extent of DNA damage. Kinetics of γ-H2AX “foci” showed early activation with low μmol/L concentrations, thus presenting a useful early biomarker of DNA damage. The half-life of γ-H2AX signal reversal after drug removal was consistent with reversal of DNA-protein cross-links. The persistence of the DNA-protein complexes induced by batracylin was markedly longer than by etoposide or camptothecin. The phosphorylated DNA damage–responsive kinase, ataxia telangiectasia mutated, was also found activated at sites of γ-H2AX. The cell cycle checkpoint kinase, Chk2, was only weakly phosphorylated. Thus, batracylin is a dual Top1 and Top2 inhibitor and γ-H2AX could be considered a biomarker in the ongoing clinical trials. [Cancer Res 2007;67(20):9971–9]
Data from RET/PTC Rearrangements Preferentially Occurred in Papillary Thyroid Cancer among Atomic Bomb Survivors Exposed to High Radiation Dose
Authors: Hamatani Kiyohiro , Eguchi Hidetaka , Ito Reiko , Mukai Mayumi , Takahashi Keiko , Taga Masataka , Imai Kazue , Cologne John , Soda Midori , Arihiro Koji , Fujihara Megumu , Abe Kuniko , Hayashi Tomayoshi , Nakashima Masahiro , Sekine Ichiro , Yasui Wataru , Hayashi Yuzo , Nakachi Kei
Published: March 2024

Abstract
A major early event in papillary thyroid carcinogenesis is constitutive activation of the mitogen-activated protein kinase signaling pathway caused by alterations of a single gene, typically rearrangements of the RET and NTRK1 genes or point mutations in the BRAF and RAS genes. In childhood papillary thyroid cancer, regardless of history of radiation exposure, RET/PTC rearrangements are a major event. Conversely, in adult-onset papillary thyroid cancer among the general population, the most common molecular event is BRAFV600E point mutation, not RET/PTC rearrangements. To clarify which gene alteration, chromosome aberration, or point mutation preferentially occurs in radiation-associated adult-onset papillary thyroid cancer, we have performed molecular analyses on RET/PTC rearrangements and BRAFV600E mutation in 71 papillary thyroid cancer cases among atomic bomb survivors (including 21 cases not exposed to atomic bomb radiation), in relation to radiation dose as well as time elapsed since atomic bomb radiation exposure. RET/PTC rearrangements showed significantly increased frequency with increased radiation dose (Ptrend = 0.002). In contrast, BRAFV600E mutation was less frequent in cases exposed to higher radiation dose (Ptrend < 0.001). Papillary thyroid cancer subjects harboring RET/PTC rearrangements developed this cancer earlier than did cases with BRAFV600E mutation (P = 0.03). These findings were confirmed by multivariate logistic regression analysis. These results suggest that RET/PTC rearrangements play an important role in radiation-associated thyroid carcinogenesis. [Cancer Res 2008;68(17):7176–82]
Data from Peripheral T-Cell Tolerance Associated with Prostate Cancer Is Independent from CD4+CD25+ Regulatory T Cells
Authors: Degl'Innocenti Elena , Grioni Matteo , Capuano Giusy , Jachetti Elena , Freschi Massimo , Bertilaccio Maria T.S. , Hess-Michelini Rodrigo , Doglioni Claudio , Bellone Matteo
Published: March 2024

Abstract
CD4+CD25+Foxp3+ regulatory T cells (Treg) are thought to suppress the natural and vaccine-induced immune response against tumor-associated antigens (TAA). Here, we show that Treg accumulate in tumors and tumor-draining lymph nodes of aging transgenic adenocarcinoma of the mouse prostate (TRAMP) male mice, which spontaneously develop prostate cancer. TAA overexpression and disease progression associate also with induction of TAA-specific tolerance. TAA-specific T cells were found in the lymphoid organs of tumor-bearing mice. However, they had lost the ability to release IFN-γ and kill relevant targets. Neither in vivo depletion of Treg by PC61 monoclonal antibody followed by repeated vaccinations with antigen-pulsed dendritic cells nor the combined treatment with 1-methyl-l-tryptophan inhibitor of the enzyme indoleamine 2,3-dyoxigenase, PC61 antibody, and dendritic cell vaccination restored the TAA-specific immune response. Treg did not seem to control the early phases of tolerance induction, as well. Indeed, depletion of Treg, starting at week 6, the age at which TRAMP mice are not yet tolerant, and prolonged up to week 12, did not avoid tolerance induction. A similar accumulation of Treg was found in the lymph nodes draining the site of dendritic cell vaccination both in TRAMP and wild-type animals. Hence, we conclude that Treg accrual is a phenomenon common to the sites of an ongoing immune response, and in TRAMP mice in particular, Treg are dispensable for induction of tumor-specific tolerance. [Cancer Res 2008;68(1):292–300]
Data from Lysosomal Cathepsin B Participates in the Podosome-Mediated Extracellular Matrix Degradation and Invasion via Secreted Lysosomes in v-Src Fibroblasts
Authors: Tu Chun , Ortega-Cava Cesar F. , Chen Gengsheng , Fernandes Norvin D. , Cavallo-Medved Dora , Sloane Bonnie F. , Band Vimla , Band Hamid
Published: March 2024

Abstract
Podosomes mediate cell migration and invasion by coordinating the reorganization of actin cytoskeleton and focal matrix degradation. MMP and serine proteases have been found to function at podosomes. The lysosomal cysteine cathepsins, a third major class of matrix-degrading enzymes involved in tumor invasion and tissue remodeling, have yet to be linked to podosomes with the exception of cathepsin K in osteoclasts. Using inhibitors and shRNA-mediated depletion, we show that cathepsin B participates in podosomes-mediated focal matrix degradation and invasion in v-Src–transformed fibroblasts. We observed that lysosomal marker LAMP-1 localized at the center of podosome rosettes protruding into extracellular matrix using confocal microscopy. Time-lapse live-cell imaging revealed that lysosomal vesicles moved to and fused with podosomes. Disruption of lysosomal pH gradient with Bafilomycin A1, chloroquine, or ammonium chloride greatly enhanced the formation of podosomes and increased the matrix degradation. Live-cell imaging showed that actin structures, induced shortly after Bafilomycin A1 treatment, were closely associated with lysosomes. Overall, our results suggest that cathepsin B, delivered by lysosomal vesicles, is involved in the matrix degradtion of podosomes. [Cancer Res 2008;68(22):9147–56]
Data from Functional and Clinical Evidence for NDRG2 as a Candidate Suppressor of Liver Cancer Metastasis
Authors: Lee Dong Chul , Kang Yun Kyung , Kim Woo Ho , Jang Ye Jin , Kim Dong Joon , Park In Young , Sohn Bo Hwa , Sohn Hyun Ahm , Lee Hee Gu , Lim Jong Seok , Kim Jae Wha , Song Eun Young , Kim Dong Min , Lee Mi-Ni , Oh Goo Taeg , Kim Soo Jung , Park Kyung Chan , Yoo Hyang Sook , Choi Jong Young , Yeom Young Il
Published: March 2024

Abstract
We searched for potential suppressors of tumor metastasis by identifying the genes that are frequently down-regulated in hepatocellular carcinomas (HCC) while being negatively correlated with clinical parameters relevant to tumor metastasis, and we report here on the identification of N-myc downstream regulated gene 2 (NDRG2) as a promising candidate. NDRG2 expression was significantly reduced in HCC compared with nontumor or normal liver tissues [87.5% (35 of 40) and 62% (62 of 100) at RNA and protein levels, respectively]. Reduction of NDRG2 expression was intimately associated with promoter hypermethylation because its promoter region was found to carry extensively methylated CpG sites in HCC cell lines and primary tumors. Immunohistochemical analysis of NDRG2 protein in 100 HCC patient tissues indicated that NDRG2 expression loss is significantly correlated with aggressive tumor behaviors such as late tumor-node-metastasis (TNM) stage (P = 0.012), differentiation grade (P = 0.024), portal vein thrombi (P = 0.011), infiltrative growth pattern (P = 0.015), nodal/distant metastasis (P = 0.027), and recurrent tumor (P = 0.021), as well as shorter patient survival rates. Ectopically expressed NDRG2 suppressed invasion and migration of a highly invasive cell line, SK-Hep-1, and experimental tumor metastasis in vivo, whereas small interfering RNA–mediated knockdown resulted in increased invasion and migration of a weakly invasive cell line, PLC/PRF/5. In addition, NDRG2 could antagonize transforming growth factor β1–mediated tumor cell invasion by specifically down-regulating the expression of matrix metalloproteinase 2 and laminin 332 pathway components, with concomitant suppression of Rho GTPase activity. These results suggest that NDRG2 can inhibit extracellular matrix–based, Rho-driven tumor cell invasion and migration and thereby play important roles in suppressing tumor metastasis in HCC. [Cancer Res 2008;68(11):4210–20]
Data from A Cryptic Vascular Endothelial Growth Factor T-Cell Epitope: Identification and Characterization by Mass Spectrometry and T-Cell Assays
Authors: Weinzierl Andreas O. , Maurer Dominik , Altenberend Florian , Schneiderhan-Marra Nicole , Klingel Karin , Schoor Oliver , Wernet Dorothee , Joos Thomas , Rammensee Hans-Georg , Stevanović Stefan
Published: March 2024

Abstract
Vascular endothelial growth factor (VEGF) is involved in various physiologic processes, such as angiogenesis or wound healing, but is also crucial in pathologic events, such as tumor growth. Thus, clinical anti-VEGF treatments have been developed that could already show beneficial effects for cancer patients. In this article, we describe the first VEGF-derived CD8+ T-cell epitope. The natural HLA ligand SRFGGAVVR was identified by differential mass spectrometry in two primary renal cell carcinomas (RCC) and was significantly overpresented on both tumor tissues. SRFGGAVVR is derived from a cryptic translated region of VEGF presumably by initiation of translation at the nonclassic start codon CUG499. SRFGGAVVR-specific T cells were generated in vitro using peptide-loaded dendritic cells or artificial antigen-presenting cells. SRFGGAVVR-specific CD8+ T cells, identified by HLA tetramer analysis after in vitro stimulation, were fully functional T effector cells, which were able to secrete IFN-γ on stimulation and killed tumor cells in vitro. Additionally, we have quantitatively analyzed VEGF mRNA and protein levels in RCC tumor and normal tissue samples by gene chip analysis, quantitative reverse transcription-PCR, in situ hybridization, and bead-based immunoassay. In the future, T cells directed against VEGF as a tumor-associated antigen may represent a possible way of combining peptide-based anti-VEGF immunotherapy with already existent anti-VEGF cancer therapies. [Cancer Res 2008;68(7):2447–54]
Data from 15-Hydroxyprostaglandin Dehydrogenase is a Target of Hepatocyte Nuclear Factor 3β and a Tumor Suppressor in Lung Cancer
Authors: Huang Guosheng , Eisenberg Rosana , Yan Min , Monti Stefano , Lawrence Earl , Fu Pingfu , Walbroehl Jaclyn , Löwenberg Ester , Golub Todd , Merchan Jaime , Tenen Daniel G. , Markowitz Sanford D. , Halmos Balazs
Published: March 2024

Abstract
The forkhead transcription factor hepatocyte nuclear factor 3β (HNF3β) is essential in foregut development and the regulation of lung-specific genes. HNF3β expression leads to growth arrest and apoptosis in lung cancer cells and HNF3β is a candidate tumor suppressor in lung cancer. In a transcriptional profiling study using a conditional cell line system, we now identify 15-PGDH as one of the major genes induced by HNF3β expression. 15-PGDH is a critical metabolic enzyme of proliferative prostaglandins, an antagonist to cyclooxygenase-2 and a tumor suppressor in colon cancer. We confirmed the regulation of 15-PGDH expression by HNF3β in a number of systems and showed direct binding of HNF3β to 15-PGDH promoter elements. Western blotting of lung cancer cell lines and immunohistochemical examination of human lung cancer tissues found loss of 15-PGDH expression in ∼65% of lung cancers. Further studies using in vitro cell-based assays and in vivo xenograft tumorigenesis assays showed a lack of in vitro but significant in vivo tumor suppressor activity of 15-PGDH via an antiangiogenic mechanism analogous to its role in colon cancer. In summary, we identify 15-PGDH as a direct downstream effector of HNF3β and show that 15-PGDH acts as a tumor suppressor in lung cancer. [Cancer Res 2008;68(13):5040–8]