bluuebunny/crossref_metadata_2025 huggingface dataset:
Selective Inhibition of Ras, Phosphoinositide 3 Kinase, and Akt Isoforms Increases the Radiosensitivity of Human Carcinoma Cell Lines
Authors: Kim In-Ah , Bae Sun-Sik , Fernandes Annemarie , Wu JunMin , Muschel Ruth J. , McKenna W. Gillies , Birnbaum Morris J. , Bernhard Eric J.
Published: July 2017

Ras activation promotes the survival of tumor cells after DNA damage. To reverse this survival advantage, Ras signaling has been targeted for inhibition. Other contributors to Ras-mediated DNA damage survival have been identified using pharmacologic inhibition of signaling, but this approach is limited by the specificity of the inhibitors used and their toxicity. To better define components of Ras signaling that could be inhibited in a clinical setting, RNA interference was used to selectively block expression of specific isoforms of Ras, phosphoinositide 3 (PI3) kinase, and Akt. Inhibition of oncogenic Ras expression decreased both phospho-Akt and phospho-p42/44 mitogen-activated protein (MAP) kinase levels and reduced clonogenic survival. Because pharmacologic inhibition of PI3 kinases and Akt radiosensitized cell lines with active Ras signaling, whereas inhibition of the MAP/extracellular signal–regulated kinase (ERK) kinase/ERK pathway did not, we examined the contribution of PI3 kinases and Akts to radiation survival. Selective inhibition the PI3 kinase P110α + p85β isoforms reduced Akt phosphorylation and radiation survival. Similarly, inhibition of Akt-1 reduced tumor cell radiation survival. Inhibition of Akt-2 or Akt-3 had less effect. Retroviral transduction and overexpression of mouse Akt-1 was shown to rescue cells from inhibition of endogenous human Akt-1 expression. This study shows that Ras signaling to the PI3 kinase–Akt pathway is an important contributor to survival, whether Ras activation results from mutation of ras or overexpression of epidermal growth factor receptor. This study further shows that selective inhibition of the PI3 kinase P110α + p85β isoforms or Akt-1 could be a viable approach to sensitizing many tumor cells to cytotoxic therapies.
Distinct Genomic Profiles in Hereditary Breast Tumors Identified by Array-Based Comparative Genomic Hybridization
Authors: Jönsson Göran , Naylor Tara L. , Vallon-Christersson Johan , Staaf Johan , Huang Jia , Ward M. Renee , Greshock Joel D. , Luts Lena , Olsson Håkan , Rahman Nazneen , Stratton Michael , Ringnér Markus , Borg Åke , Weber Barbara L.
Published: July 2017

Mutations in BRCA1 and BRCA2 account for a significant proportion of hereditary breast cancers. Earlier studies have shown that inherited and sporadic tumors progress along different somatic genetic pathways and that global gene expression profiles distinguish between these groups. To determine whether genomic profiles similarly discriminate among BRCA1, BRCA2, and sporadic tumors, we established DNA copy number profiles using comparative genomic hybridization to BAC-clone microarrays providing <1 Mb resolution. Tumor DNA was obtained from BRCA1 (n = 14) and BRCA2 (n = 12) mutation carriers, as well as sporadic cases (n = 26). Overall, BRCA1 tumors had a higher frequency of copy number alterations than sporadic breast cancers (P = 0.00078). In particular, frequent losses on 4p, 4q, and 5q in BRCA1 tumors and frequent gains on 7p and 17q24 in BRCA2 tumors distinguish these from sporadic tumors. Distinct amplicons at 3q27.1-q27.3 were identified in BRCA1 tumors and at 17q23.3-q24.2 in BRCA2 tumors. A homozygous deletion on 5q12.1 was found in a BRCA1 tumor. Using a set of 169 BAC clones that detect significantly (P < 0.001) different frequencies of copy number changes in inherited and sporadic tumors, these could be discriminated into separate groups using hierarchical clustering. By comparing DNA copy number and RNA expression for genes in these regions, several candidate genes affected by up- or down-regulation were identified. Moreover, using support vector machines, we correctly classified BRCA1 and BRCA2 tumors (P < 0.0000004 and 0.00005, respectively). Further validation may prove this tumor classifier to be useful for selecting familial breast cancer cases for further mutation screening, particularly, as these data can be obtained using archival tissue.
Mutations of β-Catenin in Adrenocortical Tumors: Activation of the Wnt Signaling Pathway Is a Frequent Event in both Benign and Malignant Adrenocortical Tumors
Authors: Tissier Frédérique , Cavard Catherine , Groussin Lionel , Perlemoine Karine , Fumey Gwladys , Hagneré Anne-Marie , René-Corail Fernande , Jullian Eric , Gicquel Christine , Bertagna Xavier , Vacher-Lavenu Marie-Cécile , Perret Christine , Bertherat Jérôme
Published: July 2017

Adrenocortical cancer is a rare cancer with a very poor prognosis. The genetic alterations identified to date in adrenocortical tumors are limited. Activating mutations of the Wnt signaling pathway have been observed in more frequent cancers, particularly digestive tract tumors. We investigated whether Wnt pathway activation is involved in adrenocortical tumorigenesis. In a series of 39 adrenocortical tumors, immunohistochemistry revealed abnormal cytoplasmic and/or nuclear accumulation of β-catenin in 10 of 26 adrenocortical adenomas and in 11 of 13 adrenocortical carcinomas. An activating somatic mutation of the β-catenin gene was shown in 7 of 26 adrenocortical adenomas and in 4 of 13 adrenocortical carcinomas; these mutations were observed only in adrenocortical tumors with abnormal β-catenin accumulation and most were point mutations altering the Ser45 of exon 3 (in the consensus GSK3-β/CK1 phosphorylation site). Functional studies showed that the activating Ser45 β-catenin mutation found in the adrenocortical cancer H295R cell line leads to constitutive activation of T-cell factor–dependent transcription. This is the first molecular defect to be reported with the same prevalence in both benign (27%) and malignant (31%) adrenocortical tumors. β-Catenin mutations are also the most frequent genetic defect currently known in adrenocortical adenomas. In adrenocortical adenomas, β-catenin alterations are more frequent in nonfunctioning tumors, suggesting that β-catenin pathway activation might be mostly involved in the development of nonsecreting adrenocortical adenomas and adrenocortical carcinomas. The very frequent and substantial accumulation of β-catenin in adrenocortical carcinomas suggests that other alterations might also be involved. This finding may contribute to new therapeutic approaches targeting the Wnt pathway in malignant adrenocortical tumors, for which limited medical therapy is available.
16-kDa Prolactin Down-Regulates Inducible Nitric Oxide Synthase Expression through Inhibition of the Signal Transducer and Activator of Transcription 1/IFN Regulatory Factor-1 Pathway
Authors: Lee Sok-hyong , Nishino Michiya , Mazumdar Tuhina , Garcia Gabriela E. , Galfione Matthew , Lee Florence L. , Lee Cynthia L. , Liang Albert , Kim Jeri , Feng Lili , Eissa N. Tony , Lin Sue-Hwa , Yu-Lee Li-yuan
Published: July 2017

Angiogenesis plays a key role in promoting tumorigenesis and metastasis. Several antiangiogenic factors have been shown to inhibit tumor growth in animal models. Understanding their mechanism of action would allow for better therapeutic application. 16-kDa prolactin (PRL), a NH2-terminal natural breakdown fragment of the intact 23-kDa PRL, exerts potent antiangiogenic and antitumor activities. The signaling mechanism involved in 16-kDa PRL action in endothelial cells remains unclear. One of the actions of 16-kDa PRL is to attenuate the production of nitric oxide (NO) through the inhibition of inducible NO synthase (iNOS) expression in endothelial cells. To delineate the signaling mechanism from 16-kDa PRL, we examined the effect of 16-kDa PRL on interleukin IL-1β–inducible iNOS expression, which is regulated by two parallel pathways, one involving IFN regulatory factor 1 (IRF-1) and the other nuclear factor-κB (NF-κB). Our studies showed that 16-kDa PRL specifically blocked IRF-1 but not NF-κB signaling to the iNOS promoter. We found that IL-1β regulated IRF-1 gene expression through stimulation of p38 mitogen-activated protein kinase (MAPK), which mediated signal transducer and activator of transcription 1 (Stat1) serine phosphorylation and Stat1 nuclear translocation to activate the IRF-1 promoter. 16-kDa PRL effectively inhibited IL-1β–inducible p38 MAPK phosphorylation, resulting in blocking Stat1 serine phosphorylation, its subsequent nuclear translocation and activation of the Stat1 target gene IRF-1. Thus, 16-kDa PRL inhibits the p38 MAPK/Stat1/IRF-1 pathway to attenuate iNOS/NO production in endothelial cells.
Functional Profiling: From Microarrays via Cell-Based Assays to Novel Tumor Relevant Modulators of the Cell Cycle
Authors: Arlt Dorit , Huber Wolfgang , Liebel Urban , Schmidt Christian , Majety Meher , Sauermann Mamatha , Rosenfelder Heiko , Bechtel Stephanie , Mehrle Alexander , Bannasch Detlev , Schupp Ingo , Seiler Markus , Simpson Jeremy C. , Hahne Florian , Moosmayer Petra , Ruschhaupt Markus , Guilleaume Birgit , Wellenreuther Ruth , Pepperkok Rainer , Sültmann Holger , Poustka Annemarie , Wiemann Stefan
Published: July 2017

Cancer transcription microarray studies commonly deliver long lists of “candidate” genes that are putatively associated with the respective disease. For many of these genes, no functional information, even less their relevance in pathologic conditions, is established as they were identified in large-scale genomics approaches. Strategies and tools are thus needed to distinguish genes and proteins with mere tumor association from those causally related to cancer. Here, we describe a functional profiling approach, where we analyzed 103 previously uncharacterized genes in cancer relevant assays that probed their effects on DNA replication (cell proliferation). The genes had previously been identified as differentially expressed in genome-wide microarray studies of tumors. Using an automated high-throughput assay with single-cell resolution, we discovered seven activators and nine repressors of DNA replication. These were further characterized for effects on extracellular signal-regulated kinase 1/2 (ERK1/2) signaling (G1-S transition) and anchorage-independent growth (tumorigenicity). One activator and one inhibitor protein of ERK1/2 activation and three repressors of anchorage-independent growth were identified. Data from tumor and functional profiling make these proteins novel prime candidates for further in-depth study of their roles in cancer development and progression. We have established a novel functional profiling strategy that links genomics to cell biology and showed its potential for discerning cancer relevant modulators of the cell cycle in the candidate lists from microarray studies.
Reciprocal Binding of CTCF and BORIS to the NY-ESO-1 Promoter Coincides with Derepression of this Cancer-Testis Gene in Lung Cancer Cells
Authors: Hong Julie A. , Kang Yang , Abdullaev Ziedulla , Flanagan Patrick T. , Pack Svetlana D. , Fischette Maria R. , Adnani Mina T. , Loukinov Dmitri I. , Vatolin Sergei , Risinger John I. , Custer Mary , Chen G. Aaron , Zhao Ming , Nguyen Dao M. , Barrett J. Carl , Lobanenkov Victor V. , Schrump David S.
Published: July 2017

Regulatory sequences recognized by the unique pair of paralogous factors, CTCF and BORIS, have been implicated in epigenetic regulation of imprinting and X chromosome inactivation. Lung cancers exhibit genome-wide demethylation associated with derepression of a specific class of genes encoding cancer-testis (CT) antigens such as NY-ESO-1. CT genes are normally expressed in BORIS-positive male germ cells deficient in CTCF and meCpG contents, but are strictly silenced in somatic cells. The present study was undertaken to ascertain if aberrant activation of BORIS contributes to derepression of NY-ESO-1 during pulmonary carcinogenesis. Preliminary experiments indicated that NY-ESO-1 expression coincided with derepression of BORIS in cultured lung cancer cells. Quantitative reverse transcription-PCR analysis revealed robust, coincident induction of BORIS and NY-ESO-1 expression in lung cancer cells, but not normal human bronchial epithelial cells following 5-aza-2′-deoxycytidine (5-azadC), Depsipeptide FK228 (DP), or sequential 5-azadC/DP exposure under clinically relevant conditions. Bisulfite sequencing, methylation-specific PCR, and chromatin immunoprecipitation (ChIP) experiments showed that induction of BORIS coincided with direct modulation of chromatin structure within a CpG island in the 5′-flanking noncoding region of this gene. Cotransfection experiments using promoter-reporter constructs confirmed that BORIS modulates NY-ESO-1 expression in lung cancer cells. Gel shift and ChIP experiments revealed a novel CTCF/BORIS-binding site in the NY-ESO-1 promoter, which unlike such sites in the H19-imprinting control region and X chromosome, is insensitive to CpG methylation in vitro. In vivo occupancy of this site by CTCF was associated with silencing of the NY-ESO-1 promoter, whereas switching from CTCF to BORIS occupancy coincided with derepression of NY-ESO-1. Collectively, these data indicate that reciprocal binding of CTCF and BORIS to the NY-ESO-1 promoter mediates epigenetic regulation of this CT gene in lung cancer cells, and suggest that induction of BORIS may be a novel strategy to augment immunogenicity of pulmonary carcinomas.
Benzodithiophenes Induce Differentiation and Apoptosis in Human Leukemia Cells
Authors: Jing Yongkui , Hellinger Nella , Xia Lijuan , Monks Anne , Sausville Edward A. , Zelent Arthur , Waxman Samuel
Published: July 2017

All-trans retinoic acid (ATRA) induces clinical remission in patients with t(15;17) acute promyelocytic leukemia (APL) carrying leukemogenic promyelocytic leukemia-retinoic acid receptor α (PML-RARα) fusion protein by overcoming PML-RARα transcriptional repression and inducing myeloid differentiation. To identify more potent chemical differentiation inducers, a screening assay was developed utilizing an ATRA-insensitive NB4 cell line (NB4-c) in which differentiation could be measured after 48 hours when primed with ATRA followed by other potential inducers. Over 300 cytostatic agents selected from the National Cancer Institute library were screened using this established method. Three compounds, NSC656243, NSC625748, and NSC144168, were identified to amplify ATRA-induced differentiation with acceptable cytotoxicity in NB4-c cells. In the absence of ATRA, these compounds also induced HL-60 and murine erythroleukemia cells to undergo partial differentiation. NSC656243, a benzodithiophene compound, was selected for further studies to examine the underlying mechanism of action. The differentiation effect of NSC656243 was associated with enhanced ATRA-mediated up-regulation of cell cycle regulatory proteins p21waf1 and p27kip1, retinoblastoma dephosphorylation, expression of RIG-E and RIG-G, and myelomonocytic differentiation–specific down-regulation of the myeloperoxidase (MPO) gene. Moreover, at 2- to 3-fold higher concentrations than those used to synergize with ATRA, NSC656243 induced apoptosis in NB4-c cells by reactive oxygen species–mediated pathways. The dual effects of benzodithiophenes (i.e., differentiation and apoptosis induction) support further development of these compounds as therapeutic agents for leukemia.
Benzodithiophenes Potentiate Differentiation of Acute Promyelocytic Leukemia Cells by Lowering the Threshold for Ligand-Mediated Corepressor/Coactivator Exchange with Retinoic Acid Receptor α and Enhancing Changes in all-trans-Retinoic Acid–Regulated Gene Expression
Authors: Xu Ke , Guidez Fabien , Glasow Annegret , Chung Danna , Petrie Kevin , Stegmaier Kimberly , Wang Kan-Kan , Zhang Ji , Jing Yongkui , Zelent Arthur , Waxman Samuel
Published: July 2017

Differentiation induction is an effective therapy for acute promyelocytic leukemia (APL), which dramatically responds to all-trans-retinoic acid (ATRA). Recent studies have indicated that combinatorial use of retinoid and nonretinoid compounds, such as histone deacetylase inhibitors, arsenics, and PKA agonists, has higher therapeutic value in this disease and potentially in other malignancies. In a screen of 370 compounds, we identified benzodithiophene analogues as potent enhancers of ATRA-induced APL cell differentiation. These effects were not associated with changes in global histone acetylation and, for the most potent compounds, were exerted at very low nanomolar concentrations, and were paralleled by enhancement of some, but not all, ATRA-modulated gene expressions. Investigating the mechanism underlying the effects of these drugs on ATRA-induced APL cell differentiation, we have shown that benzodithiophenes enhance ATRA-mediated dissociation and association of corepressor N-CoR and coactivator p300 acetyltransferase, respectively, with retinoic acid receptor (RAR) α proteins. These data suggest that benzodithiophenes act at the level of receptor activation, possibly by affecting posttranslational modification of the receptor (and/or coregulators), thus leading to an enhancement in ATRA-mediated effects on gene expression and APL cell differentiation. Given the specificities of these low benzodithiophene concentrations for PML-RARα and RARα, these drugs may be useful for combinatorial differentiation therapy of APL and possibly other acute myelogenous leukemia subtypes in which the overall ATRA signaling is suppressed.
Epidermal Growth Factor Receptor Mutations in Patients with Non–Small Cell Lung Cancer
Authors: Johnson Bruce E. , Jänne Pasi A.
Published: July 2017

A year has passed since mutations of the tyrosine kinase domain of the epidermal growth factor receptor (EGFR) were discovered in patients with non–small cell lung cancer (NSCLC) who had dramatic clinical responses to treatment with gefitinib. Additional laboratory and clinical studies have provided further insight into the biological impact of EGFR mutations in cell culture experiments and in patients with NSCLC. In vitro characterizations of NSCLC cell lines and host cell lines transfected with these mutant and wild-type EGFR show that most cell lines with mutated EGFR are growth-inhibited by 10- to 100-fold lower concentrations of gefitinib and erlotinib compared with wild-type EGFR. NSCLC lines with mutations of the EGFR treated with concentrations of gefitinib and erlotinib that are achievable in the plasma undergo apoptosis rather than growth arrest. Retrospective studies of patients with NSCLC-treated gefitinib have reported a close association between EGFR mutations, increased chance of clinical response and longer survival. This review will provide information on the impact of EGFR mutations on gefitinib and erlotinib treatment by in vitro experiments, the outcome of NSCLC patients with these mutations when treated with gefitinib and erlotinib, and the subsets of patients with NSCLC in whom these mutations arise.
Tumor Radiosensitization by Antiinflammatory Drugs: Evidence for a New Mechanism Involving the Oxygen Effect
Authors: Crokart Nathalie , Radermacher Kim , Jordan Bénédicte F. , Baudelet Christine , Cron Gregory O. , Grégoire Vincent , Beghein Nelson , Bouzin Caroline , Feron Olivier , Gallez Bernard
Published: July 2017

We hypothesized that nonsteroidal antiinflammatory drugs (NSAIDs) might enhance tumor radiosensitivity by increasing tumor oxygenation (pO2), via either a decrease in the recruitment of macrophages or from inhibition of mitochondrial respiration. The effect of four NSAIDs (diclofenac, indomethacin, piroxicam, and NS-398) on pO2 was studied in murine TLT liver tumors and FSaII fibrosarcomas. At the time of maximum pO2 (tmax, 30 minutes after administration), perfusion, oxygen consumption, and radiation sensitivity were studied. Local pO2 measurements were done using electron paramagnetic resonance. Tumor perfusion and permeability measurements were assessed by dynamic contrast-enhanced magnetic resonance imaging. The oxygen consumption rate of tumor cells after in vivo NSAID administration was measured using high-frequency electron paramagnetic resonance. Tumor-infiltrating macrophage localization was done with immunohistochemistry using CD11b antibody. All the NSAIDs tested caused a rapid increase in pO2. At tmax, tumor perfusion decreased, indicating that the increase in pO2 was not caused by an increase in oxygen supply. Also at tmax, global oxygen consumption decreased but the amount of tumor-infiltrating macrophages remained unchanged. Our study strongly indicates that the oxygen effect caused by NSAIDs is primarily mediated by an effect on mitochondrial respiration. When irradiation (18 Gy) was applied at tmax, the tumor radiosensitivity was enhanced (regrowth delay increased by a factor of 1.7). These results show the potential utility of an acute administration of NSAIDs for radiosensitizing tumors, and shed new light on the mechanisms of NSAID radiosensitization. These results also provide a new rationale for the treatment schedule when combining NSAIDs and radiotherapy.
Modulation of Gene Expression in Precancerous Rat Esophagus by Dietary Zinc Deficit and Replenishment
Authors: Liu Chang-Gong , Zhang Liang , Jiang Yubao , Chatterjee Devjani , Croce Carlo M. , Huebner Kay , Fong Louise Y.Y.
Published: July 2017

Zinc deficiency in rats enhances esophageal cell proliferation, causes alteration in gene expression, and promotes esophageal carcinogenesis. Zinc replenishment rapidly induces apoptosis in the esophageal epithelium thereby reversing cell proliferation and carcinogenesis. To identify zinc-responsive genes responsible for these divergent effects, we did oligonucleotide array-based gene expression profiling analyses in the precancerous zinc-deficient esophagus and in zinc-replenished esophagi after treatment with intragastric zinc compared with zinc-sufficient esophagi. Thirty-three genes (21 up-regulated and 12 down-regulated) showed a ≥2-fold change in expression in the hyperplastic zinc-deficient versus zinc-sufficient esophageal epithelia. Expression of genes involved in cell division, survival, adhesion, and tumorigenesis were markedly changed. The zinc-sensitive gene metallothionein-1 (MT-1 was up-regulated 7-fold, the opposite of results for small intestine and liver under zinc-deficient conditions. Keratin 14 (KRT14, a biomarker in esophageal tumorigenesis), carbonic anhydrase II (CAII, a regulator of acid-base homeostasis), and cyclin B were up-regulated >4-fold. Immunohistochemistry showed that metallothionein and keratin 14 proteins were overexpressed in zinc-deficient esophagus, as well as in lingual and esophageal squamous cell carcinoma from carcinogen-treated rats, emphasizing their roles in carcinogenesis. Calponin 1 (CNN1, an actin cross-linking regulator) was down-regulated 0.2-fold. Within hours after oral zinc treatment, the abnormal expression of 29 of 33 genes returned to near zinc-sufficient levels, accompanied by reversal of the precancerous phenotype. Thus, we have identified new molecular markers in precancerous esophagus and showed their restoration by zinc replenishment, providing insights into the interaction between zinc and gene expression in esophageal cancer development and prevention.
Regulation of Prostaglandin Metabolism by Calcitriol Attenuates Growth Stimulation in Prostate Cancer Cells
Authors: Moreno Jacqueline , Krishnan Aruna V. , Swami Srilatha , Nonn Larisa , Peehl Donna M. , Feldman David
Published: July 2017

Calcitriol exhibits antiproliferative and prodifferentiation effects in prostate cancer. Our goal is to further define the mechanisms underlying these actions. We studied established human prostate cancer cell lines and primary prostatic epithelial cells and showed that calcitriol regulated the expression of genes involved in the metabolism of prostaglandins (PGs), known stimulators of prostate cell growth. Calcitriol significantly repressed the mRNA and protein expression of prostaglandin endoperoxide synthase/cyclooxygenase-2 (COX-2), the key PG synthesis enzyme. Calcitriol also up-regulated the expression of 15-hydroxyprostaglandin dehydrogenase, the enzyme initiating PG catabolism. This dual action was associated with decreased prostaglandin E2 secretion into the conditioned media of prostate cancer cells exposed to calcitriol. Calcitriol also repressed the mRNA expression of the PG receptors EP2 and FP, providing a potential additional mechanism of suppression of the biological activity of PGs. Calcitriol treatment attenuated PG-mediated functional responses, including the stimulation of prostate cancer cell growth. The combination of calcitriol with nonsteroidal anti-inflammatory drugs (NSAIDs) synergistically acted to achieve significant prostate cancer cell growth inhibition at ∼2 to 10 times lower concentrations of the drugs than when used alone. In conclusion, the regulation of PG metabolism and biological actions constitutes a novel pathway of calcitriol action that may contribute to its antiproliferative effects in prostate cells. We propose that a combination of calcitriol and nonselective NSAIDs might be a useful chemopreventive and/or therapeutic strategy in men with prostate cancer, as it would allow the use of lower concentrations of both drugs, thereby reducing their toxic side effects.
Targeted Destruction of c-Myc by an Engineered Ubiquitin Ligase Suppresses Cell Transformation and Tumor Formation
Authors: Hatakeyama Shigetsugu , Watanabe Masashi , Fujii Yo , Nakayama Keiichi I.
Published: July 2017

Given that expression of c-Myc is up-regulated in many human malignancies, targeted inactivation of this oncoprotein is a potentially effective strategy for cancer treatment. The ubiquitin-proteasome pathway of protein degradation is highly specific and can be engineered to achieve the elimination of undesirable proteins such as oncogene products. We have now generated a fusion protein (designated Max-U) that is composed both of Max, which forms a heterodimer with c-Myc, and of CHIP, which is a U box-type ubiquitin ligase (E3). Max-U physically interacted with c-Myc in transfected cells and promoted the ubiquitylation of c-Myc in vitro. It also reduced the stability of c-Myc in vivo, resulting in suppression of transcriptional activity dependent on c-Myc. Expression of Max-U reduced both the abundance of endogenous c-Myc in and the proliferation rate of a Burkitt lymphoma cell line. Furthermore, expression of Max-U but not that of a catalytically inactive mutant thereof markedly inhibited both the anchorage-independent growth in vitro of NIH 3T3 cells that overexpress c-Myc as well as tumor formation by these cells in nude mice. These findings indicate that the targeted destruction of c-Myc by an artificial E3 may represent an effective therapeutic strategy for certain human malignancies.
Somatic Mutations of the Protein Kinase Gene Family in Human Lung Cancer
Authors: Davies Helen , Hunter Chris , Smith Raffaella , Stephens Philip , Greenman Chris , Bignell Graham , Teague Jon , Butler Adam , Edkins Sarah , Stevens Claire , Parker Adrian , O'Meara Sarah , Avis Tim , Barthorpe Syd , Brackenbury Lisa , Buck Gemma , Clements Jody , Cole Jennifer , Dicks Ed , Edwards Ken , Forbes Simon , Gorton Matthew , Gray Kristian , Halliday Kelly , Harrison Rachel , Hills Katy , Hinton Jonathon , Jones David , Kosmidou Vivienne , Laman Ross , Lugg Richard , Menzies Andrew , Perry Janet , Petty Robert , Raine Keiran , Shepherd Rebecca , Small Alexandra , Solomon Helen , Stephens Yvonne , Tofts Calli , Varian Jennifer , Webb Anthony , West Sofie , Widaa Sara , Yates Andrew , Brasseur Francis , Cooper Colin S. , Flanagan Adrienne M. , Green Anthony , Knowles Maggie , Leung Suet Y. , Looijenga Leendert H.J. , Malkowicz Bruce , Pierotti Marco A. , Teh Bin T. , Yuen Siu T. , Lakhani Sunil R. , Easton Douglas F. , Weber Barbara L. , Goldstraw Peter , Nicholson Andrew G. , Wooster Richard , Stratton Michael R. , Futreal P. Andrew
Published: July 2017

Protein kinases are frequently mutated in human cancer and inhibitors of mutant protein kinases have proven to be effective anticancer drugs. We screened the coding sequences of 518 protein kinases (∼1.3 Mb of DNA per sample) for somatic mutations in 26 primary lung neoplasms and seven lung cancer cell lines. One hundred eighty-eight somatic mutations were detected in 141 genes. Of these, 35 were synonymous (silent) changes. This result indicates that most of the 188 mutations were “passenger” mutations that are not causally implicated in oncogenesis. However, an excess of ∼40 nonsynonymous substitutions compared with that expected by chance (P = 0.07) suggests that some nonsynonymous mutations have been selected and are contributing to oncogenesis. There was considerable variation between individual lung cancers in the number of mutations observed and no mutations were found in lung carcinoids. The mutational spectra of most lung cancers were characterized by a high proportion of C:G > A:T transversions, compatible with the mutagenic effects of tobacco carcinogens. However, one neuroendocrine cancer cell line had a distinctive mutational spectrum reminiscent of UV-induced DNA damage. The results suggest that several mutated protein kinases may be contributing to lung cancer development, but that mutations in each one are infrequent.
CIB2 Negatively Regulates Oncogenic Signaling in Ovarian Cancer via Sphingosine Kinase 1
Authors: Zhu Wenying , Jarman Kate E. , Lokman Noor A. , Neubauer Heidi A. , Davies Lorena T. , Gliddon Briony L. , Taing Houng , Moretti Paul A.B. , Oehler Martin K. , Pitman Melissa R. , Pitson Stuart M.
Published: July 2017

Sphingosine kinase 1 (SK1) is a key regulator of the cellular balance between proapoptotic and prosurvival sphingolipids. Oncogenic signaling by SK1 relies on its localization to the plasma membrane, which is mediated by the calcium and integrin binding protein CIB1 via its Ca2+-myristoyl switch function. Here we show that another member of the CIB family, CIB2, plays a surprisingly opposite role to CIB1 in the regulation of SK1 signaling. CIB2 bound SK1 on the same site as CIB1, yet it lacks the Ca2+-myristoyl switch function. As a result, CIB2 blocked translocation of SK1 to the plasma membrane and inhibited its subsequent signaling, which included sensitization to TNFα-induced apoptosis and inhibition of Ras-induced neoplastic transformation. CIB2 was significantly downregulated in ovarian cancer and low CIB2 expression was associated with poor prognosis in ovarian cancer patients. Notably, reintroduction of CIB2 in ovarian cancer cells blocked plasma membrane localization of endogenous SK1, reduced in vitro neoplastic growth and tumor growth in mice, and suppressed cell motility and invasiveness both in vitro and in vivo. Consistent with the in vitro synergistic effects between the SK1-specific inhibitor SK1-I and standard chemotherapeutics, expression of CIB2 also sensitized ovarian cancer cells to carboplatin. Together, these findings identify CIB2 as a novel endogenous suppressor of SK1 signaling and potential prognostic marker and demonstrate the therapeutic potential of SK1 in this gynecologic malignancy. Cancer Res; 77(18); 4823–34. ©2017 AACR.
Overexpressed P-Cadherin/CDH3 Promotes Motility of Pancreatic Cancer Cells by Interacting with p120ctn and Activating Rho-Family GTPases
Authors: Taniuchi Keisuke , Nakagawa Hidewaki , Hosokawa Masayo , Nakamura Toru , Eguchi Hidetoshi , Ohigashi Hiroaki , Ishikawa Osamu , Katagiri Toyomasa , Nakamura Yusuke
Published: July 2017

P-Cadherin/CDH3 belongs to the family of classic cadherins that are engaged in various cellular activities including motility, invasion, and signaling of tumor cells, in addition to cell adhesion. However, the biological roles of P-cadherin itself are not fully characterized. Based on information derived from a previous genome-wide cDNA microarray analysis of microdissected pancreatic ductal adenocarcinoma (PDAC), we focused on P-cadherin as one of the genes most strongly overexpressed in the great majority of PDACs. To investigate the consequences of overexpression of P-cadherin in terms of pancreatic carcinogenesis and tumor progression, we used a P-cadherin–deficient PDAC cell line, Panc-1, to construct a cell line (Panc1-CDH3) that stably overexpressed P-cadherin. Induction of P-cadherin in Panc1-CDH3 increased the motility of the cancer cells, but a blocking antibody against P-cadherin suppressed the motility in vitro. Overexpression of P-cadherin was strongly associated with cytoplasmic accumulation of one of the catenins, p120ctn, and cadherin switching in PDAC cells. Moreover, P-cadherin–dependent activation of cell motility was associated with activation of Rho GTPases, Rac1 and Cdc42, through accumulation of p120ctn in cytoplasm and cadherin switching. These findings suggest that overexpression of P-cadherin is likely to be related to the biological aggressiveness of PDACs; blocking of P-cadherin activity or its associated signaling could be a novel therapeutic approach for treatment of aggressive pancreatic cancers.
Magnetic Resonance Spectroscopy Monitoring of Mitogen-Activated Protein Kinase Signaling Inhibition
Authors: Beloueche-Babari Mounia , Jackson L. Elizabeth , Al-Saffar Nada M.S. , Workman Paul , Leach Martin O. , Ronen Sabrina M.
Published: July 2017

Several mitogen-activated protein kinase (MAPK) signaling inhibitors are currently undergoing clinical trial as part of novel mechanism-based anticancer treatment strategies. This study was aimed at detecting biomarkers of MAPK signaling inhibition in human breast and colon carcinoma cells using magnetic resonance spectroscopy. We investigated the effect of the prototype MAPK kinase inhibitor U0126 on the 31P-MR spectra of MDA-MB-231, MCF-7 and Hs578T breast, and HCT116 colon carcinoma cells. Treatment of MDA-MB-231 cells with 50 μmol/L U0126 for 2, 4, 8, 16, 24, 32, and 40 hours caused inhibition of extracellular signal–regulated kinases (ERK1/2) phosphorylation from 2 hours onwards. 31P-MR spectra of extracted cells indicated that this was associated with a significant drop in phosphocholine levels to 78 ± 8% at 8 hours, 74 ± 8% at 16 hours, 66 ± 7% at 24 hours, 71 ± 10% at 32 hours, and 65 ± 10% at 40 hours post-treatment. In contrast, the lower concentration of 10 μmol/L U0126 for 40 hours had no significant effect on either P-ERK1/ 2 or phosphocholine levels in MDA-MB-231 cells. Depletion of P-ERK1/2 in MCF-7 and Hs578T cells with 50 μmol/L U0126 also produced a drop in phosphocholine levels to 51 ± 17% at 40 hours and 23 ± 12% at 48 hours, respectively. Similarly, in HCT116 cells, inhibition with 30 μmol/L U0126 caused depletion of P-ERK1/2 and a decrease in phosphocholine levels to 80 ± 9% at 16 hours and 61 ± 4% at 24 hours post-treatment. The reduction in phosphocholine in MDA-MB-231 and HCT116 cells correlated positively with the drop in P-ERK1/2 levels. Our results show that MAPK signaling inhibition with U0126 is associated with a time-dependent decrease in cellular phosphocholine levels. Thus, phosphocholine has potential as a noninvasive pharmacodynamic marker for monitoring MAPK signaling blockade.
Decitabine Priming Enhances Mucin 1 Inhibition Mediated Disruption of Redox Homeostasis in Cutaneous T-Cell Lymphoma
Authors: Jain Salvia , Washington Abigail , Leaf Rebecca Karp , Bhargava Parul , Clark Rachael A. , Kupper Thomas S. , Stroopinsky Dina , Pyzer Athalia , Cole Leandra , Nahas Myrna , Apel Arie , Rosenblatt Jacalyn , Arnason Jon , Kufe Donald , Avigan David
Published: July 2017

Cutaneous T-cell lymphoma (CTCL) is a heterogeneous neoplasm and patients with relapsed/refractory disease exhibit resistance to standard therapies. We have previously demonstrated that the Mucin 1 C-terminal subunit (MUC1-C) plays a critical role in protection from oxidative stress in CTCL cells. Targeting of MUC1-C with a pharmacologic inhibitor, GO-203, was associated with apoptosis in CTCL. However, disease responses were incomplete underscoring the need for combinatorial strategies that could exploit the vulnerability of CTCL cells to oxidative signals. Cell lines, primary samples, and xenograft models of CTCL were used to assess synergy of GO-203 with decitabine, a hypomethylating agent. Present studies demonstrate that exposure of CTCL cells to decitabine in combination with GO-203, increased the generation of reactive oxygen species (ROS) levels and decreased levels of scavenger molecules, NADP, NADPH, glutathione, and TIGAR, critical to intracellular redox homeostasis. Dual exposure to GO-203 and decitabine resulted in marked downregulation of DNA methyl transferases demonstrating significant synergy of these agents in inducing global and gene specific hypomethylation. Accordingly, treatment with decitabine and GO-203 upregulated the ROS generating enzymes, NADPH oxidase 4 and dual oxidase 2 potentially due to their effect on epigenomic regulation of these proteins. In concert with these findings, exposure to decitabine and GO-203 resulted in heightened apoptotic death in CTCL cell lines, patient-derived primary samples and in a murine xenograft model. These findings indicate that decitabine intensifies MUC1-C inhibition induced redox imbalance and provides a novel combination of targeted and epigenetic agents for patients with CTCL. Mol Cancer Ther; 16(10); 2304–14. ©2017 AACR.
JAK1/STAT3 Activation through a Proinflammatory Cytokine Pathway Leads to Resistance to Molecularly Targeted Therapy in Non–Small Cell Lung Cancer
Authors: Shien Kazuhiko , Papadimitrakopoulou Vassiliki A. , Ruder Dennis , Behrens Carmen , Shen Li , Kalhor Neda , Song Juhee , Lee J. Jack , Wang Jing , Tang Ximing , Herbst Roy S. , Toyooka Shinichi , Girard Luc , Minna John D. , Kurie Jonathan M. , Wistuba Ignacio I. , Izzo Julie G.
Published: July 2017

Molecularly targeted drugs have yielded significant therapeutic advances in oncogene-driven non–small cell lung cancer (NSCLC), but a majority of patients eventually develop acquired resistance. Recently, the relation between proinflammatory cytokine IL6 and resistance to targeted drugs has been reported. We investigated the functional contribution of IL6 and the other members of IL6 family proinflammatory cytokine pathway to resistance to targeted drugs in NSCLC cells. In addition, we examined the production of these cytokines by cancer cells and cancer-associated fibroblasts (CAF). We also analyzed the prognostic significance of these molecule expressions in clinical NSCLC samples. In NSCLC cells with acquired resistance to targeted drugs, we observed activation of the IL6–cytokine pathway and STAT3 along with epithelial-to-mesenchymal transition (EMT) features. In particular, IL6 family cytokine oncostatin-M (OSM) induced a switch to the EMT phenotype and protected cells from targeted drug-induced apoptosis in OSM receptors (OSMRs)/JAK1/STAT3–dependent manner. The cross-talk between NSCLC cells and CAFs also preferentially activated the OSM/STAT3 pathway via a paracrine mechanism and decreased sensitivity to targeted drugs. The selective JAK1 inhibitor filgotinib effectively suppressed STAT3 activation and OSMR expression, and cotargeting inhibition of the oncogenic pathway and JAK1 reversed resistance to targeted drugs. In the analysis of clinical samples, OSMR gene expression appeared to be associated with worse prognosis in patients with surgically resected lung adenocarcinoma. Our data suggest that the OSMRs/JAK1/STAT3 axis contributes to resistance to targeted drugs in oncogene-driven NSCLC cells, implying that this pathway could be a therapeutic target. Mol Cancer Ther; 16(10); 2234–45. ©2017 AACR.
Vessel-Targeted Chemophototherapy with Cationic Porphyrin-Phospholipid Liposomes
Authors: Luo Dandan , Geng Jumin , Li Nasi , Carter Kevin A. , Shao Shuai , Atilla-Gokcumen G. Ekin , Lovell Jonathan F.
Published: July 2017

Cationic liposomes have been used for targeted drug delivery to tumor blood vessels, via mechanisms that are not fully elucidated. Doxorubicin (Dox)-loaded liposomes were prepared that incorporate a cationic lipid; 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP), along with a small amount of porphyrin-phospholipid (PoP). Near-infrared (NIR) light caused release of entrapped Dox via PoP-mediated DOTAP photo-oxidation. The formulation was optimized to enable extremely rapid NIR light-triggered Dox release (i.e., in 15 seconds), while retaining reasonable serum stability. In vitro, cationic PoP liposomes readily bound to both MIA PaCa-2 human pancreatic cancer cells and human vascular endothelial cells. When administered intravenously, cationic PoP liposomes were cleared from circulation within minutes, with most accumulation in the liver and spleen. Fluorescence imaging revealed that some cationic PoP liposomes also localized at the tumor blood vessels. Compared with analogous neutral liposomes, strong tumor photoablation was induced with a single treatment of cationic PoP liposomes and laser irradiation (5 mg/kg Dox and 100 J/cm2 NIR light). Unexpectedly, empty cationic PoP liposomes (lacking Dox) induced equally potent antitumor phototherapeutic effects as the drug loaded ones. A more balanced chemo- and phototherapeutic response was subsequently achieved when antitumor studies were repeated using higher drug dosing (7 mg/kg Dox) and a low fluence phototreatment (20 J/cm2 NIR light). These results demonstrate the feasibility of vessel-targeted chemophototherapy using cationic PoP liposomes and also illustrate synergistic considerations. Mol Cancer Ther; 16(11); 2452–61. ©2017 AACR.
Inclusion of a Genetic Risk Score into a Validated Risk Prediction Model for Colorectal Cancer in Japanese Men Improves Performance
Authors: Iwasaki Motoki , Tanaka-Mizuno Sachiko , Kuchiba Aya , Yamaji Taiki , Sawada Norie , Goto Atsushi , Shimazu Taichi , Sasazuki Shizuka , Wang Hansong , Marchand Loïc Le , Tsugane Shoichiro
Published: July 2017

We previously developed and validated a risk prediction model for colorectal cancer in Japanese men using modifiable risk factors. To further improve risk prediction, we evaluated the degree of improvement obtained by adding a genetic risk score (GRS) using genome-wide association study (GWAS)-identified risk variants to our validated model. We examined the association between 36 risk variants identified by GWAS and colorectal cancer risk using a weighted Cox proportional hazards model in a nested case–control study within the Japan Public Health Center-based Prospective Study. GRS was constructed using six variants associated with risk in this study of the 36 tested. We assessed three models: a nongenetic model that included the same variables used in our previously validated model; a genetic model that used GRS; and an inclusive model, which included both. The c-statistic, integrated discrimination improvement (IDI), and net reclassification improvement (NRI) were calculated by the 5-fold cross-validation method. We estimated 10-year absolute risks for developing colorectal cancer. A statistically significant association was observed between the weighted GRS and colorectal cancer risk. The mean c-statistic for the inclusive model (0.66) was slightly greater than that for the nongenetic model (0.60). Similarly, the mean IDI and NRI showed improvement when comparing the nongenetic and inclusive models. These models for colorectal cancer were well calibrated. The addition of GRS using GWAS-identified risk variants to our validated model for Japanese men improved the prediction of colorectal cancer risk. Cancer Prev Res; 10(9); 535–41. ©2017 AACR.
Tumor Evolution as a Therapeutic Target
Authors: Amirouchene-Angelozzi Nabil , Swanton Charles , Bardelli Alberto
Published: July 2017

Recent technological advances in the field of molecular diagnostics (including blood-based tumor genotyping) allow the measurement of clonal evolution in patients with cancer, thus adding a new dimension to precision medicine: time. The translation of this new knowledge into clinical benefit implies rethinking therapeutic strategies. In essence, it means considering as a target not only individual oncogenes but also the evolving nature of human tumors. Here, we analyze the limitations of targeted therapies and propose approaches for treatment within an evolutionary framework.

Significance: Precision cancer medicine relies on the possibility to match, in daily medical practice, detailed genomic profiles of a patient's disease with a portfolio of drugs targeted against tumor-specific alterations. Clinical blockade of oncogenes is effective but only transiently; an approach to monitor clonal evolution in patients and develop therapies that also evolve over time may result in improved therapeutic control and survival outcomes. Cancer Discov; 7(8); 805–17. ©2017 AACR.
Superenhancer Analysis Defines Novel Epigenomic Subtypes of Non-APL AML, Including an RARα Dependency Targetable by SY-1425, a Potent and Selective RARα Agonist
Authors: McKeown Michael R. , Corces M. Ryan , Eaton Matthew L. , Fiore Chris , Lee Emily , Lopez Jeremy T. , Chen Mei Wei , Smith Darren , Chan Steven M. , Koenig Julie L. , Austgen Kathryn , Guenther Matthew G. , Orlando David A. , Lovén Jakob , Fritz Christian C. , Majeti Ravindra
Published: July 2017

We characterized the enhancer landscape of 66 patients with acute myeloid leukemia (AML), identifying 6 novel subgroups and their associated regulatory loci. These subgroups are defined by their superenhancer (SE) maps, orthogonal to somatic mutations, and are associated with distinct leukemic cell states. Examination of transcriptional drivers for these epigenomic subtypes uncovers a subset of patients with a particularly strong SE at the retinoic acid receptor alpha (RARA) gene locus. The presence of a RARA SE and concomitant high levels of RARA mRNA predisposes cell lines and ex vivo models to exquisite sensitivity to a selective agonist of RARα, SY-1425 (tamibarotene). Furthermore, only AML patient-derived xenograft (PDX) models with high RARA mRNA were found to respond to SY-1425. Mechanistically, we show that the response to SY-1425 in RARA-high AML cells is similar to that of acute promyelocytic leukemia treated with retinoids, characterized by the induction of known retinoic acid response genes, increased differentiation, and loss of proliferation.

Significance: We use the SE landscape of primary human AML to elucidate transcriptional circuitry and identify novel cancer vulnerabilities. A subset of patients were found to have an SE at RARA, which is predictive for response to SY-1425, a potent and selective RARα agonist, in preclinical models, forming the rationale for its clinical investigation in biomarker-selected patients. Cancer Discov; 7(10); 1136–53. ©2017 AACR.

See related commentary by Wang and Aifantis, p. 1065..

This article is highlighted in the In This Issue feature, p. 1047
OS SERMÕES DE QUARTA-FEIRA DE CINZA DO PADRE ANTÔNIO VIEIRA E A ARTE DE MORRER ESTOICO-CRISTÃ
Authors: Lachat Marcelo
Published: July 2017

Neste artigo, discutem-se os Sermões de Quarta-Feira de Cinza do Padre Antônio Vieira, destacando-se neles a arte estoico-cristã do saber morrer. Isso porque, nesses três sermões, centrados na passagem bíblica “és pó e em pó te tornarás” (Gênesis, 3: 19), evidenciam-se preceitos estoicos – em particular de Sêneca – mesclados à doutrina cristã, que visam, por meio de ponderações sobre a morte, pautar o comportamento dos vivos. Assim, pretende-se demonstrar que nos Sermões de Cinza de Vieira, o saber morrer é uma arte cujos preceitos devem ser aprendidos e praticados, tendo como uma de suas principais fontes a filosofia estoica. Se nessa ars, como preceitua Sêneca, “a vida toda é um aprender a morrer” (De Breuitate Vitae VII, 3-4), as agudas cinzas dos sermões de Vieira são luzes da morte e sombras da vida, sempre a lembrar: memento homo, quia pulvis es et in pulverem reverteris. Enfim, o pó é escarmento vivo e constante da morte.