bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from The Deubiquitinating Enzyme USP17 Is Highly Expressed in Tumor Biopsies, Is Cell Cycle Regulated, and Is Required for G1-S Progression
Authors: McFarlane Cheryl , Kelvin Alyson A. , de la Vega Michelle , Govender Ureshnie , Scott Christopher J. , Burrows James F. , Johnston James A.
Published: March 2024

Abstract
Ubiquitination is a reversible posttranslational modification that is essential for cell cycle control, and it is becoming increasingly clear that the removal of ubiquitin from proteins by deubiquitinating enzymes (DUB) is equally important. In this study, we have identified high levels of the DUB USP17 in several tumor-derived cell lines and primary lung, colon, esophagus, and cervix tumor biopsies. We also report that USP17 is tightly regulated during the cell cycle in all the cells examined, being abundantly evident in G1 and absent in S phase. Moreover, regulated USP17 expression was necessary for cell cycle progression because its depletion significantly impaired G1-S transition and blocked cell proliferation. Previously, we have shown that USP17 regulates the intracellular translocation and activation of the GTPase Ras by controlling Ras-converting enzyme 1 (RCE1) activation. RCE1 also regulates the processing of other proteins with a CAAX motif, including Rho family GTPases. We now show that USP17 depletion blocks Ras and RhoA localization and activation. Moreover, our results confirm that USP17-depleted cells have constitutively elevated levels of the cyclin-dependent kinase inhibitors p21cip1 and p27kip1, known downstream targets of Ras and RhoA signaling. These observations clearly show that USP17 is tightly regulated during cell division and that its expression is necessary to coordinate cell cycle progression, and thus, it may be considered a promising novel cancer therapeutic target. Cancer Res; 70(8); 3329–39. ©2010 AACR.
Data from Hepatocyte Nuclear Factor-4α Promotes Gut Neoplasia in Mice and Protects against the Production of Reactive Oxygen Species
Authors: Darsigny Mathieu , Babeu Jean-Philippe , Seidman Ernest G. , Gendron Fernand-Pierre , Levy Emile , Carrier Julie , Perreault Nathalie , Boudreau François
Published: March 2024

Abstract
Hepatocyte nuclear factor-4α (Hnf4α) is a transcription factor that controls epithelial cell polarity and morphogenesis. Hnf4α conditional deletion during postnatal development has minor effects on intestinal epithelium integrity but promotes activation of the Wnt/β-catenin pathway without causing tumorigenesis. Here, we show that Hnf4α does not act as a tumor-suppressor gene but is crucial in promoting gut tumorigenesis in mice. Polyp multiplicity in ApcMin mice lacking Hnf4α is suppressed compared with littermate ApcMin controls. Analysis of microarray gene expression profiles from mice lacking Hnf4α in the intestinal epithelium identifies novel functions of this transcription factor in targeting oxidoreductase-related genes involved in the regulation of reactive oxygen species (ROS) levels. This role is supported with the demonstration that HNF4α is functionally involved in the protection against spontaneous and 5-fluorouracil chemotherapy-induced production of ROS in colorectal cancer cell lines. Analysis of a colorectal cancer patient cohort establishes that HNF4α is significantly upregulated compared with adjacent normal epithelial resections. Several genes involved in ROS neutralization are also induced in correlation with HNF4A expression. Altogether, the findings point to the nuclear receptor HNF4α as a potential therapeutic target to eradicate aberrant epithelial cell resistance to ROS production during intestinal tumorigenesis. Cancer Res; 70(22); 9423–33. ©2010 AACR.
Data from Role of Epidermal Growth Factor Receptor Degradation in Cisplatin-Induced Cytotoxicity in Head and Neck Cancer
Authors: Ahsan Aarif , Hiniker Susan M. , Ramanand Susmita G. , Nyati Shyam , Hegde Ashok , Helman Abigail , Menawat Radhika , Bhojani Mahaveer S. , Lawrence Theodore S. , Nyati Mukesh K.
Published: March 2024

Abstract
Cisplatin and its analogues are the most commonly used agents in the treatment of head and neck squamous cell carcinoma. In this study, we investigated a possible role of epidermal growth factor (EGF) receptor (EGFR) phosphorylation and degradation in cisplatin-induced cytotoxicity. Cisplatin treatment led to an increase in initial EGFR phosphorylation at Y1045, the binding site of ubiquitin ligase, Casitas B-lineage lymphoma (c-Cbl), followed by ubiquitination in the relatively cisplatin-sensitive cell lines. However, cisplatin-resistant cell lines underwent minimal EGFR phosphorylation at the Y1045 site and minimal ubiquitination. We found that EGFR degradation in response to cisplatin was highly correlated with cytotoxicity in seven head and neck cancer cell lines. Pretreatment with EGF enhanced cisplatin-induced EGFR degradation and cytotoxicity, whereas erlotinib pretreatment blocked EGFR phosphorylation, degradation, and cisplatin-induced cytotoxicity. Expression of a mutant Y1045F EGFR, which is relatively resistant to c-Cbl–mediated degradation, in Chinese hamster ovary cells and the UMSCC11B human head and neck cancer cell line protected EGFR from cisplatin-induced degradation and enhanced cell survival compared with wild-type (WT) EGFR. Transfection of WT c-Cbl enhanced EGFR degradation and cisplatin-induced cytotoxicity compared with control vector. These results show that cisplatin-induced EGFR phosphorylation and subsequent ubiquitination and degradation is an important determinant of cisplatin sensitivity. Our findings suggest that treatment with an EGFR inhibitor before cisplatin would be antagonistic, as EGFR inhibition would protect EGFR from cisplatin-mediated phosphorylation and subsequent ubiquitination and degradation, which may explain the negative results of several recent clinical trials. Furthermore, they suggest that EGFR degradation is worth exploring as an early biomarker of response and as a target to improve outcome. Cancer Res; 70(7); 2862–9
Data from Metabolic Profiling Detects Field Effects in Nondysplastic Tissue from Esophageal Cancer Patients
Authors: Yakoub Danny , Keun Hector C. , Goldin Robert , Hanna George B.
Published: March 2024

Abstract
The variable rate of missed cancer in endoscopic biopsies and lack of other biomarkers reduce the effectiveness of surveillance programs in esophageal cancer. Based on the “field cancerization” hypothesis that tumors arise within a transformed field with an altered biochemical phenotype, we sought to test if metabolic profiling could differentiate between histologically normal tissue from individuals with and without esophageal cancer. Thirty-five patients with esophageal adenocarcinoma and 52 age-matched controls participated in the study. Using 1H magic angle spinning–nuclear magnetic resonance spectroscopy of intact tissue, we generated metabolic profiles of tumor tissue, proximal histologically normal mucosa from cancer patients (PHINOM), and proximal histologically normal mucosa from a control group. Using multivariate regression and receiver-operator characteristic analysis, we identified a panel of metabolites discriminating malignant and histologically normal tissues from cancer patients and from that of controls. Whereas 26% and 12% of the spectral profile regions were uniquely discriminating tumor or control tissue, respectively, 5% of the profile exhibited a significant progressive change in signal intensity from controls to PHINOM to tumor. Regions identified were assigned to phosphocholine (PC), glutamate (Glu), myo-inositol, adenosine-containing compounds, uridine-containing compounds, and inosine. In particular, the PC/Glu ratio in histologically normal tissue signified the presence of esophageal cancer (n = 123; area under the curve, 0.84; P < 0.001). In conclusion, our findings support the hypothesis of the presence of metabonomic field effects in esophageal cancer, even in non-Barrett's segments. This indicates that metabolic profiling of tissue can potentially play a role in the surveillance of cancer by reporting on the phenotypic consequences of field cancerization. Cancer Res; 70(22); 9129–36. ©2010 AACR.
Data from Microphthalmia-Associated Transcription Factor Controls the DNA Damage Response and a Lineage-Specific Senescence Program in Melanomas
Authors: Giuliano Sandy , Cheli Yann , Ohanna Mickaël , Bonet Caroline , Beuret Laurent , Bille Karine , Loubat Agnès , Hofman Véronique , Hofman Paul , Ponzio Gilles , Bahadoran Philippe , Ballotti Robert , Bertolotto Corine
Published: March 2024

Abstract
Apoptosis and senescence are cellular failsafe programs that counteract excessive mitogenic signaling observed in cancer cells. Melanoma is known for its notorious resistance to apoptotic processes; therefore, senescence, which remains poorly understood in melanomas, can be viewed as a therapeutic alternative. Microphthalmia-associated transcription factor (MITF), in which its M transcript is specifically expressed in melanocyte cells, plays a critical role in melanoma proliferation, and its specific inhibition is associated with G0-G1 growth arrest. Interestingly, decreased MITF expression has been described in senescent melanocytes, and we have observed an inhibition of MITF expression in melanoma cells exposed to chemotherapeutic drugs that induce their senescence. All these observations thereby question the role of MITF in controlling senescence in melanoma cells. Here, we report that long-term depletion of MITF in melanoma cells triggers a senescence program characterized by typical morphologic and biochemical changes associated with a sustained growth arrest. Further, we show that MITF-silenced cells engage a DNA damage response (DDR) signaling pathway, leading to p53 upregulation, which is critically required for senescence entry. This study uncovers the existence of a lineage-restricted DDR/p53 signaling pathway that is inhibited by MITF to prevent senescence and favor melanoma cell proliferation. Cancer Res; 70(9); 3813–22. ©2010 AACR.
Data from Hierarchical Clustering of Human Papilloma Virus Genotype Patterns in the ASCUS-LSIL Triage Study
Authors: Wentzensen Nicolas , Wilson Lauren E. , Wheeler Cosette M. , Carreon Joseph D. , Gravitt Patti E. , Schiffman Mark , Castle Philip E.
Published: March 2024

Abstract
Anogenital cancers are associated with ∼13 carcinogenic human papilloma virus (HPV) types in a broader group that cause cervical intraepithelial neoplasia (CIN). Multiple concurrent cervical HPV infections are common, which complicates the attribution of HPV types to different grades of CIN. Here we report the analysis of HPV genotype patterns in the atypical squamous cells of undetermined significance–low-grade squamous intraepithelial lesion triage study with the use of unsupervised hierarchical clustering. Women who underwent colposcopy at baseline (n = 2,780) were grouped into 20 disease categories based on histology and cytology. Disease groups and HPV genotypes were clustered with the use of complete linkage. Risk of 2-year cumulative CIN3+, viral load, colposcopic impression, and age were compared between disease groups and major clusters. Hierarchical clustering yielded four major disease clusters: cluster 1 included all CIN3 histology with abnormal cytology; cluster 2 included CIN3 histology with normal cytology and combinations with either CIN2 or high-grade squamous intraepithelial lesion cytology; cluster 3 included older women with normal or low-grade histology/cytology and low viral load; and cluster 4 included younger women with low-grade histology/cytology, multiple infections, and the highest viral load. Three major groups of HPV genotypes were identified: group 1 included only HPV16; group 2 included nine carcinogenic types, plus noncarcinogenic HPV53 and HPV66; and group 3 included noncarcinogenic types, plus carcinogenic HPV33 and HPV45. Clustering results suggested that colposcopy missed a prevalent precancer in many women with no biopsy/normal histology and high-grade squamous intraepithelial lesion. This result was confirmed by an elevated 2-year risk of CIN3+ in these groups. Our novel approach to study multiple genotype infections in cervical disease with the use of unsupervised hierarchical clustering can address complex genotype distributions on a population level. Cancer Res; 70(21); 8578–86. ©2010 AACR.
Data from Inflammatory Processes Triggered by Helicobacter pylori Infection Cause Aberrant DNA Methylation in Gastric Epithelial Cells
Authors: Niwa Tohru , Tsukamoto Tetsuya , Toyoda Takeshi , Mori Akiko , Tanaka Harunari , Maekita Takao , Ichinose Masao , Tatematsu Masae , Ushijima Toshikazu
Published: March 2024

Abstract
Altered patterns of DNA methylation associated with Helicobacter pylori (HP) infection of gastric epithelial cells are thought to contribute to gastric cancer risk. However, it is unclear whether this increased risk reflects an infection-associated inflammatory response or the infection itself. In this study, we sought to clarify mechanisms in a gerbil model of gastric cancer where we showed that HP infection is causally involved in induction of aberrant DNA methylation. By genome-wide screening, CpG islands that were aberrantly methylated in gerbil gastric cancer cell lines were isolated, and 10 islands were shown to be specifically methylated only in gastric mucosae infected with HP. By temporal analysis, methylation levels in gastric epithelial cells started to increase at 5 to 10 weeks after infection and reached high levels by 50 weeks. When HP was eradicated, methylation levels markedly decreased 10 and 20 weeks later, but they remained higher than those in gerbils that were not infected by HP. Expression levels of several inflammation-related genes (CXCL2, IL-1β, NOS2, and TNF-α) paralleled the temporal changes of methylation levels. Significantly suppressing inflammation with the immunosuppressive drug cyclosporin A did not affect colonization by HP but blocked the induction of altered DNA methylation. Our findings argue that DNA methylation alterations that occur in gastric mucosae after HP infection are composed of transient components and permanent components, and that it is the infection-associated inflammatory response, rather than HP itself, which is responsible for inducing the altered DNA methylation. Cancer Res; 70(4); 1430–40
Data from Early Detection of Recurrent Breast Cancer Using Metabolite Profiling
Authors: Asiago Vincent M. , Alvarado Leiddy Z. , Shanaiah Narasimhamurthy , Gowda G.A. Nagana , Owusu-Sarfo Kwadwo , Ballas Robert A. , Raftery Daniel
Published: March 2024

Abstract
We report on the development of a monitoring test for recurrent breast cancer, using metabolite-profiling methods. Using a combination of nuclear magnetic resonance (NMR) and two-dimensional gas chromatography–mass spectrometry (GC×GC-MS) methods, we analyzed the metabolite profiles of 257 retrospective serial serum samples from 56 previously diagnosed and surgically treated breast cancer patients. One hundred sixteen of the serial samples were from 20 patients with recurrent breast cancer, and 141 samples were from 36 patients with no clinical evidence of the disease during ∼6 years of sample collection. NMR and GC×GC-MS data were analyzed by multivariate statistical methods to compare identified metabolite signals between the recurrence samples and those with no evidence of disease. Eleven metabolite markers (seven from NMR and four from GC×GC-MS) were shortlisted from an analysis of all patient samples by using logistic regression and 5-fold cross-validation. A partial least squares discriminant analysis model built using these markers with leave-one-out cross-validation provided a sensitivity of 86% and a specificity of 84% (area under the receiver operating characteristic curve = 0.88). Strikingly, 55% of the patients could be correctly predicted to have recurrence 13 months (on average) before the recurrence was clinically diagnosed, representing a large improvement over the current breast cancer–monitoring assay CA 27.29. To the best of our knowledge, this is the first study to develop and prevalidate a prediction model for early detection of recurrent breast cancer based on metabolic profiles. In particular, the combination of two advanced analytical methods, NMR and MS, provides a powerful approach for the early detection of recurrent breast cancer. Cancer Res; 70(21); 8309–18. ©2010 AACR.
Data from Expression Profiling in Progressive Stages of Fumarate-Hydratase Deficiency: The Contribution of Metabolic Changes to Tumorigenesis
Authors: Ashrafian Houman , O'Flaherty Linda , Adam Julie , Steeples Violetta , Chung Yuen-Li , East Phil , Vanharanta Sakari , Lehtonen Heli , Nye Emma , Hatipoglu Emine , Miranda Melroy , Howarth Kimberley , Shukla Deepa , Troy Helen , Griffiths John , Spencer-Dene Bradley , Yusuf Mohammed , Volpi Emanuela , Maxwell Patrick H. , Stamp Gordon , Poulsom Richard , Pugh Christopher W. , Costa Barbara , Bardella Chiara , Di Renzo Maria Flavia , Kotlikoff Michael I. , Launonen Virpi , Aaltonen Lauri , El-Bahrawy Mona , Tomlinson Ian , Pollard Patrick J.
Published: March 2024

Abstract
Hereditary leiomyomatosis and renal cell carcinoma (HLRCC) is caused by mutations in the Krebs cycle enzyme fumarate hydratase (FH). It has been proposed that “pseudohypoxic” stabilization of hypoxia-inducible factor-α (HIF-α) by fumarate accumulation contributes to tumorigenesis in HLRCC. We hypothesized that an additional direct consequence of FH deficiency is the establishment of a biosynthetic milieu. To investigate this hypothesis, we isolated primary mouse embryonic fibroblast (MEF) lines from Fh1-deficient mice. As predicted, these MEFs upregulated Hif-1α and HIF target genes directly as a result of FH deficiency. In addition, detailed metabolic assessment of these MEFs confirmed their dependence on glycolysis, and an elevated rate of lactate efflux, associated with the upregulation of glycolytic enzymes known to be associated with tumorigenesis. Correspondingly, Fh1-deficient benign murine renal cysts and an advanced human HLRCC-related renal cell carcinoma manifested a prominent and progressive increase in the expression of HIF-α target genes and in genes known to be relevant to tumorigenesis and metastasis. In accord with our hypothesis, in a variety of different FH-deficient tissues, including a novel murine model of Fh1-deficient smooth muscle, we show a striking and progressive upregulation of a tumorigenic metabolic profile, as manifested by increased PKM2 and LDHA protein. Based on the models assessed herein, we infer that that FH deficiency compels cells to adopt an early, reversible, and progressive protumorigenic metabolic milieu that is reminiscent of that driving the Warburg effect. Targets identified in these novel and diverse FH-deficient models represent excellent potential candidates for further mechanistic investigation and therapeutic metabolic manipulation in tumors. Cancer Res; 70(22); 9153–65. ©2010 AACR.
Data from The Connectivity Map Links Iron Regulatory Protein-1–Mediated Inhibition of Hypoxia-Inducible Factor-2a Translation to the Anti-inflammatory 15-deoxy-Δ12,14-Prostaglandin J2
Authors: Zimmer Michael , Lamb Justin , Ebert Benjamin L. , Lynch Mary , Neil Christopher , Schmidt Emmett , Golub Todd R. , Iliopoulos Othon
Published: March 2024

Abstract
Hypoxia-inducible factors 1 and 2 (HIF1 and HIF2) are heterodimeric transcription factors consisting of α regulatory subunits and a constitutively expressed β subunit. The expression of α regulatory subunits is promoted by hypoxia, cancer-associated mutations, and inflammatory cytokines. Thus, HIF1 and HIF2 provide a molecular link between cancer and inflammation. We have recently identified novel small molecules that selectively inhibit translation of the HIF2a message and thereby powerfully inhibit the expression of HIF2a target genes. We report here that Connectivity Map analysis links three of these compounds to the anti-inflammatory cytokine 15-deoxy-Δ12,14-prostaglandin J2 (PGJ2). As with our identified compounds, PGJ2 inhibits translation of the HIF2a message in a mammalian target of rapamycin–independent manner by promoting the binding of iron regulatory protein-1 (IRP1) to a noncanonical iron responsive element (IRE) embedded within the 5′-untranslated region of the HIF2a message. The IRE is necessary and sufficient for mediating the effect. Mutation of the IRE sequence, or downregulation of IRP1 expression, blocks the effect of PGJ2 on HIF2a translation. This is the first report of an endogenous natural molecule regulating HIF2a translation, and it suggests that part of the anti-inflammatory and putative antineoplastic effects of PGJ2 may be mediated through inhibition of HIF2a within tumor epithelial cells themselves and/or mesenchymal cells of the tumor microenvironment. Cancer Res; 70(8); 3071–9. ©2010 AACR.
Data from LYN Is a Mediator of Epithelial-Mesenchymal Transition and a Target of Dasatinib in Breast Cancer
Authors: Choi Yoon-La , Bocanegra Melanie , Kwon Mi Jeong , Shin Young Kee , Nam Seok Jin , Yang Jung-Hyun , Kao Jessica , Godwin Andrew K. , Pollack Jonathan R.
Published: March 2024

Abstract
Epithelial-mesenchymal transition (EMT), a switch of polarized epithelial cells to a migratory, fibroblastoid phenotype, is considered a key process driving tumor cell invasiveness and metastasis. Using breast cancer cell lines as a model system, we sought to discover gene expression signatures of EMT with clinical and mechanistic relevance. A supervised comparison of epithelial and mesenchymal breast cancer lines defined a 200-gene EMT signature that was prognostic across multiple breast cancer cohorts. The immunostaining of LYN, a top-ranked EMT signature gene and Src-family tyrosine kinase, was associated with significantly shorter overall survival (P = 0.02) and correlated with the basal-like (“triple-negative”) phenotype. In mesenchymal breast cancer lines, RNAi-mediated knockdown of LYN inhibited cell migration and invasion, but not proliferation. Dasatinib, a dual-specificity tyrosine kinase inhibitor, also blocked invasion (but not proliferation) at nanomolar concentrations that inhibit LYN kinase activity, suggesting that LYN is a likely target and that invasion is a relevant end point for dasatinib therapy. Our findings define a prognostically relevant EMT signature in breast cancer and identify LYN as a mediator of invasion and a possible new therapeutic target (and theranostic marker for dasatinib response), with particular relevance to clinically aggressive basal-like breast cancer. Cancer Res; 70(6); 2296–306
Data from Novel Synthetic Antagonists of Canonical Wnt Signaling Inhibit Colorectal Cancer Cell Growth
Authors: Waaler Jo , Machon Ondrej , von Kries Jens Peter , Wilson Steven Ray , Lundenes Elsa , Wedlich Doris , Gradl Dietmar , Paulsen Jan Erik , Machonova Olga , Dembinski Jennifer L. , Dinh Huyen , Krauss Stefan
Published: March 2024

Abstract
Canonical Wnt signaling is deregulated in several types of human cancer where it plays a central role in tumor cell growth and progression. Here we report the identification of 2 new small molecules that specifically inhibit canonical Wnt pathway at the level of the destruction complex. Specificity was verified in various cellular reporter systems, a Xenopus double-axis formation assay and a gene expression profile analysis. In human colorectal cancer (CRC) cells, the new compounds JW67 and JW74 rapidly reduced active β-catenin with a subsequent downregulation of Wnt target genes, including AXIN2, SP5, and NKD1. Notably, AXIN2 protein levels were strongly increased after compound exposure. Long-term treatment with JW74 inhibited the growth of tumor cells in both a mouse xenograft model of CRC and in ApcMin mice (multiple intestinal neoplasia, Min). Our findings rationalize further preclinical and clinical evaluation of these new compounds as novel modalities for cancer treatment. Cancer Res; 71(1); 197–205. ©2010 AACR.
Data from Synergistic Enhancement of Carboplatin Efficacy with Photodynamic Therapy in a Three-Dimensional Model for Micrometastatic Ovarian Cancer
Authors: Rizvi Imran , Celli Jonathan P. , Evans Conor L. , Abu-Yousif Adnan O. , Muzikansky Alona , Pogue Brian W. , Finkelstein Dianne , Hasan Tayyaba
Published: March 2024

Abstract
Metastatic ovarian cancer (OvCa) frequently recurs due to chemoresistance, highlighting the need for nonoverlapping combination therapies that mechanistically synergize to eradicate residual disease. Photodynamic therapy (PDT), a photochemistry-based cytotoxic modality, sensitizes ovarian tumors to platinum agents and biologics and has shown clinical promise against ovarian carcinomatosis. We introduce a three-dimensional (3D) model representing adherent ovarian micrometastases and high-throughput quantitative imaging methods to rapidly screen the order-dependent effects of combining benzoporphyrin-derivative (BPD) monoacid A–based PDT with low-dose carboplatin. 3D ovarian micronodules grown on Matrigel were subjected to BPD-PDT either before or after carboplatin treatment. We developed custom fluorescence image analysis routines to quantify residual tumor volume and viability. Carboplatin alone did not eradicate ovarian micrometastases at a dose of 400 mg/m2, leaving surviving cores that were nonsensitive or impermeable to chemotherapy. BPD-PDT (1.25 μmol/L·J/cm2) created punctate cytotoxic regions within tumors and disrupted micronodular structure. Treatment with BPD-PDT prior to low-dose carboplatin (40 mg/m2) produced a significant synergistic reduction [P < 0.0001, analysis of covariance (ANCOVA)] in residual tumor volume [0.26; 95% confidence interval (95% CI), 0.19–0.36] compared with PDT alone (0.76; 95% CI, 0.63–0.92) or carboplatin alone (0.95; 95% CI, 0.83–1.09), relative to controls. This synergism was not observed with the reverse treatment order. Here, we demonstrate for the first time the use of a 3D model for micrometastatic OvCa as a rapid and quantitative reporter to optimize sequence and dosing regimens of clinically relevant combination strategies. This approach combining biological modeling with high-content imaging provides a platform to rapidly screen therapeutic strategies for a broad array of metastatic tumors. Cancer Res; 70(22); 9319–28. ©2010 AACR.
Data from Chromosome Breakage Is Regulated by the Interaction of the BLM Helicase and Topoisomerase IIα
Authors: Russell Beatriz , Bhattacharyya Saumitri , Keirsey Jeremy , Sandy April , Grierson Patrick , Perchiniak Erin , Kavecansky Juraj , Acharya Samir , Groden Joanna
Published: March 2024

Abstract
Cells deficient in the recQ-like helicase BLM are characterized by chromosome changes that suggest the disruption of normal mechanisms needed to resolve recombination intermediates and to maintain chromosome stability. Human BLM and topoisomerase IIα interact directly via amino acids 489–587 of BLM and colocalize predominantly in late G2 and M phases of the cell cycle. Deletion of this region does not affect the inherent in vitro helicase activity of BLM but inhibits the topoisomerase IIα–dependent enhancement of its activity, based on the analysis of specific DNA substrates that represent some recombination intermediates. Deletion of the interaction domain from BLM fails to correct the elevated chromosome breakage of transfected BLM-deficient cells. Our results demonstrate that the BLM–topoisomerase IIα interaction is important for preventing chromosome breakage and elucidate a DNA repair mechanism that is critical to maintain chromosome stability in cells and to prevent tumor formation. Cancer Res; 71(2); 561–71. ©2011 AACR.
Data from Microfluidic-Based Multiplex qRT-PCR Identifies Diagnostic and Prognostic microRNA Signatures in the Sera of Prostate Cancer Patients
Authors: Moltzahn Felix , Olshen Adam B. , Baehner Lauren , Peek Andrew , Fong Lawrence , Stöppler Hubert , Simko Jeffry , Hilton Joan F. , Carroll Peter , Blelloch Robert
Published: March 2024

Abstract
Recent prostate-specific antigen–based screening trials indicate an urgent need for novel and noninvasive biomarker identification strategies to improve the prediction of prostate cancer behavior. Noncoding microRNAs (miRNA) in the serum and plasma have been shown to have potential as noninvasive markers for physiologic and pathologic conditions. To identify serum miRNAs that diagnose and correlate with the prognosis of prostate cancer, we developed a multiplex quantitative reverse transcription PCR method involving the purification of multiplex PCR products followed by uniplex analysis on a microfluidics chip to evaluate 384 human miRNAs. Using Dgcr8 and Dicer knockout (small RNA-deficient) mouse ES cells as the benchmark, we confirmed the validity of our technique and uncovered a considerable lack of accuracy in previously published methods. Profiling 48 sera from healthy men and untreated prostate cancer patients with differing CAPRA scores, we identified miRNA signatures that allow us to diagnose cancer patients and correlate with a prognosis. These serum signatures include oncogenic and tumor-suppressive miRNAs, suggesting functional roles in prostate cancer progression. Cancer Res; 71(2); 550–60. ©2010 AACR.
Data from An Illegitimate microRNA Target Site within the 3′ UTR of MDM4 Affects Ovarian Cancer Progression and Chemosensitivity
Authors: Wynendaele Jessika , Böhnke Anja , Leucci Eleonora , Nielsen Søren Jensby , Lambertz Irina , Hammer Stefanie , Sbrzesny Nadja , Kubitza Dana , Wolf Anja , Gradhand Elise , Balschun Katharina , Braicu Ioana , Sehouli Jalid , Darb-Esfahani Silvia , Denkert Carsten , Thomssen Christoph , Hauptmann Steffen , Lund Anders , Marine Jean-Christophe , Bartel Frank
Published: March 2024

Abstract
Overexpression of MDM4 (also known as MDMX or HDMX) is thought to promote tumorigenesis by decreasing p53 tumor suppressor function. Even modest decrease in Mdm4 levels affects tumorigenesis in mice, suggesting that genetic variants of MDM4 might have similar effects in humans. We sequenced the MDM4 gene in a series of ovarian cancer cell lines and carcinomas to identify mutations and/or single nucleotide polymorphisms (SNPs). We identified an SNP (SNP34091) in the 3′-UTR of MDM4 that creates a putative target site for hsa-miR-191, a microRNA that is highly expressed in normal and tumor tissues. Biochemical evidence supports specific miR-191–dependent regulation of the MDM4-C, but not MDM4-A, variant. Consistently, the A-allele was associated with statistically significant increased expression of MDM4 mRNA and protein levels in ovarian carcinomas. Importantly, the wild-type genotype (A/A) is more frequent (57.8% vs. 42.2% for A/C and C/C, respectively) in patients with high-grade carcinomas than in patients with low-grade carcinomas (47.2% vs. 52.5% for A/A and A/C + C/C, respectively). Moreover, A/A patients who do not express the estrogen receptor had a 4.2-fold [95% confidence interval (CI) = 1.2–13.5; P = 0.02] increased risk of recurrence and 5.5-fold (95% CI = 1.5–20.5; P = 0.01) increased risk of tumor-related death. Unexpectedly, the frequency of p53 mutations was not significantly lower in A/A patients. We conclude that acquisition of an illegitimate miR-191 target site causes downregulation of MDM4 expression, thereby significantly delaying ovarian carcinoma progression and tumor-related death. Importantly, these effects appear to be, at least partly, independent of p53. Cancer Res; 70(23); 9641–9. ©2010 AACR.
Data from hTERT Overexpression Alleviates Intracellular ROS Production, Improves Mitochondrial Function, and Inhibits ROS-Mediated Apoptosis in Cancer Cells
Authors: Indran Inthrani R. , Hande Manoor P. , Pervaiz Shazib
Published: March 2024

Abstract
The human telomerase reverse transcriptase (hTERT) is the catalytic subunit of the telomerase holoenzyme. Evidence is accumulating to link hTERT to activities other than telomere maintenance and immortalization. Here, we show that hTERT overexpression not only reduces the basal cellular reactive oxygen species (ROS) levels but also inhibits endogenous ROS production in response to stimuli that induce intracellular ROS generation. Conversely, siRNA-mediated gene silencing of hTERT potentiated the increase in cellular ROS levels following exposure to oxidative stress. This antioxidant effect of hTERT is mediated via a significant increase in the ratio of reduced to oxidized glutathione (GSH:GSSG) as well as efficient recovery of the oxidized peroxiredoxin to its nonoxidized form. Our data also provide evidence for mitochondrial localization of hTERT, and a significantly higher activity of cytochrome C oxidase, the rate-limiting enzyme in the mitochondrial electron transport chain, in hTERT overexpressing cells. To ascertain whether the improved mitochondrial function and antioxidant effect of hTERT could provide cancer cells with a survival advantage, the effect of oxidative stress on mitochondrial apoptosis was evaluated. Indeed, hTERT overexpressing cells inhibited cytosolic acidification, translocation of Bax, the drop in mitochondrial transmembrane potential, the release of cytochrome C to the cytosol, and cell death. Taken together, these data demonstrate a hitherto undefined role of hTERT in alleviating cellular ROS levels by way of potentiating the cellular antioxidant defense systems, and in doing so endowing cancer cells with the ability to evade death stimuli. Cancer Res; 71(1); 266–76. ©2010 AACR.
Data from Telomere Length in Prospective and Retrospective Cancer Case-Control Studies
Authors: Pooley Karen A. , Sandhu Manjinder S. , Tyrer Jonathan , Shah Mitul , Driver Kristy E. , Luben Robert N. , Bingham Sheila A. , Ponder Bruce A.J. , Pharoah Paul D.P. , Khaw Kay-Tee , Easton Douglas F. , Dunning Alison M.
Published: March 2024

Abstract
Previous studies have reported that shorter mean telomere length in lymphocytes was associated with increased susceptibility to common diseases of aging, and may be predictive of cancer risk. However, most analyses have examined retrospectively collected case-control studies. Mean telomere length was measured using high-throughput quantitative real-time PCR. Blood for DNA extraction was collected after cancer diagnosis in the East Anglian SEARCH Breast (2,243 cases and 2,181 controls) and SEARCH Colorectal (2,249 cases and 2,161 controls) studies. Prospective case-control studies were conducted for breast cancer (199 cases) and colorectal cancer (185 cases), nested within the EPIC-Norfolk cohort. Blood was collected at least 6 months prior to diagnosis, and was matched to DNA from two cancer-free controls per case. In the retrospective SEARCH studies, the age-adjusted odds ratios for shortest (Q4) versus longest (Q1) quartile of mean telomere length was 15.5 [95% confidence intervals (CI), 11.6–20.8; p-het = 5.7 × 10−75], with a “per quartile” P-trend = 2.1 × 10−80 for breast cancer; and 2.14 (95% CI, 1.77–2.59; p-het = 7.3 × 10−15), with a per quartile P-trend = 1.8 × 10−13 for colorectal cancer. In the prospective EPIC study, the comparable odds ratios (Q4 versus Q1) were 1.58 (95% CI, 0.75–3.31; p-het = 0.23) for breast cancer and 1.13 (95% CI, 0.54–2.36; p-het = 0.75) for colorectal cancer risk. Mean telomere length was shorter in retrospectively collected cases than in controls but the equivalent association was markedly weaker in the prospective studies. This suggests that telomere shortening largely occurs after diagnosis, and therefore, might not be of value in cancer prediction. Cancer Res; 70(8); 3170–6. ©2010 AACR.
Data from Protein Kinase Cι Is Required for Pancreatic Cancer Cell Transformed Growth and Tumorigenesis
Authors: Scotti Michele L. , Bamlet William R. , Smyrk Thomas C. , Fields Alan P. , Murray Nicole R.
Published: March 2024

Abstract
Pancreatic cancer is the fourth leading cause of cancer deaths in the United States, with an overall 5-year survival rate of <5%. Pancreatic ductal adenocarcinoma (PDAC), the most common form of pancreatic cancer, is highly resistant to conventional chemotherapies, underscoring the critical need for new molecular targets for pancreatic cancer chemotherapy. The KRAS proto-oncogene is mutated in >90% of PDAC. Protein kinase Cι (PKCι) is required for the oncogenic Ras–mediated transformed growth of lung cancer and intestinal epithelial cells. However, little is known about the role of PKCι in pancreatic cancer. In this study, we evaluated the expression of PKCι in human pancreatic cancer and the requirement for PKCι for the transformed growth and tumorigenicity of PDAC cells. We find that PKCι is significantly overexpressed in human pancreatic cancer, and high PKCι expression correlates with poor patient survival. Inhibition of PKCι expression blocks PDAC cell transformed growth in vitro and tumorigenicity in vivo. Inhibition of PKCι expression in pancreatic tumors also significantly reduces tumor angiogenesis and metastasis. Analysis of downstream PKCι effectors implicates the Rac1-MEK/ERK1/2 signaling axis in PKCι-mediated transformed growth and cellular invasion. Taken together, our data show a required role for PKCι in the transformed growth of pancreatic cancer cells and reveal a novel role for PKCι in pancreatic cancer cell metastasis and angiogenesis in vivo. Our results strongly indicate that PKCι will be an effective target for pancreatic cancer therapy. Cancer Res; 70(5); 2064–74
Data from Loss of DNA Polymerase ζ Enhances Spontaneous Tumorigenesis
Authors: Wittschieben John P. , Patil Vaishali , Glushets Veronika , Robinson Lisa J. , Kusewitt Donna F. , Wood Richard D.
Published: March 2024

Abstract
Mammalian genomes encode at least 15 distinct DNA polymerases, functioning as specialists in DNA replication, DNA repair, recombination, or bypass of DNA damage. Although the DNA polymerase ζ (polζ) catalytic subunit REV3L is important in defense against genotoxins, little is known of its biological function. This is because REV3L is essential during embryogenesis, unlike other translesion DNA polymerases. Outstanding questions include whether any adult cells are viable in the absence of polζ and whether polζ status influences tumorigenesis. REV3L-deficient cells have properties that could influence the development of neoplasia in opposing ways: markedly reduced damage-induced point mutagenesis and extensive chromosome instability. To answer these questions, Rev3L was conditionally deleted from tissues of adult mice using MMTV-Cre. Loss of REV3L was tolerated in epithelial tissues but not in the hematopoietic lineage. Thymic lymphomas in Tp53−/− Rev3L conditional mice occurred with decreased latency and higher incidence. The lymphomas were populated predominantly by Rev3L-null T cells, showing that loss of Rev3L can promote tumorigenesis. Remarkably, the tumors were frequently oligoclonal, consistent with accelerated genetic changes in the absence of Rev3L. Mammary tumors could also arise from Rev3L-deleted cells in both Tp53+/+ and Tp53+/− backgrounds. Mammary tumors in Tp53+/− mice deleting Rev3L formed months earlier than mammary tumors in Tp53+/− control mice. Prominent preneoplastic changes in glandular tissue adjacent to these tumors occurred only in mice deleting Rev3L and were associated with increased tumor multiplicity. Polζ is the only specialized DNA polymerase yet identified that inhibits spontaneous tumor development. Cancer Res; 70(7); 2770–8
Data from FLT3-Mediated p38–MAPK Activation Participates in the Control of Megakaryopoiesis in Primary Myelofibrosis
Authors: Desterke Christophe , Bilhou-Nabéra Chrystele , Guerton Bernadette , Martinaud Christophe , Tonetti Carole , Clay Denis , Guglielmelli Paola , Vannucchi Alessandro , Bordessoule Dominique , Hasselbalch Hans , Dupriez Brigitte , Benzoubir Nassima , Bourgeade Marie-Françoise , Pierre-Louis Olivier , Lazar Vladimir , Vainchenker William , Bennaceur-Griscelli Annelise , Gisslinger Heinz , Giraudier Stéphane , Le Bousse-Kerdilès Marie-Caroline
Published: March 2024

Abstract
Primary myelofibrosis (PMF) is characterized by increased number of hematopoietic progenitors and a dysmegakaryopoiesis which supports the stromal reaction defining this disease. We showed that increased ligand (FL) levels in plasma, hematopoietic progenitors, and stromal cells from PMF patients were associated with upregulation of the cognate Flt3 receptor on megakaryocytic (MK) cells. This connection prompted us to study a functional role for the FL/Flt3 couple in PMF dysmegakaryopoiesis, as a route to reveal insights into pathobiology and therapy in this disease. Analysis of PMF CD34+ and MK cell transcriptomes revealed deregulation of the mitogen-activated protein kinase (MAPK) pathway along with Flt3 expression. In PMF patients, a higher proportion of circulating Flt3+CD34+CD41+ cells exhibited an increased MAPK effector phosphorylation independently of Jak2V617F mutation. Activation of FL/Flt3 axis in PMF MK cell cultures, in response to FL, induced activation of the p38–MAPK cascade, which is known to be involved in inflammation, also increasing expression of its target genes (NFATC4, p53, AP-1, IL-8). Inhibiting Flt3 or MAPK or especially p38 by chemical, antibody, or silencing strategies restored megakaryopoiesis and reduced phosphorylation of Flt3 and p38 pathway effectors, confirming the involvement of Flt3 in PMF dysmegakaryopoiesis via p38 activation. In addition, in contrast to healthy donors, MK cells derived from PMF CD34+ cells exhibited an FL-induced migration that could be reversed by p38 inhibition. Taken together, our results implicate the FL/Flt3 ligand–receptor complex in PMF dysmegakaryopoiesis through persistent p38–MAPK activation, with implications for therapeutic prospects to correct altered megakaryopoiesis in an inflammatory context. Cancer Res; 71(8); 2901–15. ©2011 AACR.
Data from ErbB2 Trafficking and Degradation Associated with K48 and K63 Polyubiquitination
Authors: Marx Corina , Held Jason M. , Gibson Bradford W. , Benz Christopher C.
Published: March 2024

Abstract
The overexpressed ErbB2/HER2 receptor is a clinically validated cancer target whose surface localization and internalization mechanisms remain poorly understood. Downregulation of the overexpressed 185-kDa ErbB2 receptor is rapidly (2–6 hours) induced by the HSP90 chaperone inhibitor geldanamycin (GA), whereas its downregulation and lysosomal degradation are more slowly (24 hours) induced by the proteasome inhibitor bortezomib/PS341. In PS341-treated SK-BR-3 cells, overexpressed ErbB2 coprecipitates with the E3 ubiquitin ligase c-Cbl and also with the deubiquitinating enzyme USP9x; moreover, siRNA downregulation of USP9x enhances PS341-induced ErbB2 downregulation. Because polyubiquitin linkages via lysine 48 (K48) or 63 (K63) can differentially address proteins for 26S proteasomal degradation or endosome trafficking to the lysosome, multiple reaction monitoring (MRM)/mass spectrometry (MS) and polyubiquitin linkage–specific antibodies were used to quantitatively track K48-linked and K63-linked ErbB2 polyubiquitination following either GA or PS341 treatment of SK-BR-3 cells. MRM/MS revealed that unlike the rapid, modest (4-fold to 8-fold), and synchronous GA induction of K48 and K63 polyubiquitinated ErbB2, PS341 produces a dramatic (20-fold to 40-fold) sequential increase in polyubiquitinated ErbB2 consistent with K48 polyubiquitination followed by K63 editing. Fluorescence microscopic imaging confirmed that PS341, but not GA, induces colocalization of K48-linked and K63-linked polyubiquitin with perinuclear lysosome-sequestered ErbB2. Thus, ErbB2 surface overexpression and recycling seem to depend on its polyubiquitination and deubiquitination; as well, the contrasting effects of PS341 and GA on ErbB2 receptor localization, polyubiquitination, and degradation point to alternate cytoplasmic trafficking likely regulated by different K48 and K63 polyubiquitin editing mechanisms. Cancer Res; 70(9); 3709–17. ©2010 AACR.
Data from The LMP7-K Allele of the Immunoproteasome Exhibits Reduced Transcript Stability and Predicts High Risk of Colon Cancer
Authors: Fellerhoff Barbara , Gu Songhai , Laumbacher Barbara , Nerlich Andreas G. , Weiss Elisabeth H. , Glas Jürgen , Kopp Reinhard , Johnson Judith P. , Wank Rudolf
Published: March 2024

Abstract
Destruction of cancer cells by cytotoxic T lymphocytes depends on immunogenic tumor peptides generated by proteasomes and presented by human leukocyte antigen (HLA) molecules. Functional differences arising from alleles of immunoproteasome subunits have not been recognized so far. We analyzed the genetic polymorphism of the immunoproteasome subunits LMP2 and LMP7 and of the transporters associated with antigen processing (TAP1 and TAP2) in two independently collected panels of colorectal carcinoma patients (N1 = 112, N2 = 62; controls, N = 165). High risk of colon cancer was associated with the LMP7-K/Q genotype (OR = 8.10, P = 1.10 × 10−11) and low risk with the LMP7-Q/Q genotype (OR = 0.10, P = 5.97 × 10−13). The basis for these distinct associations of LMP7 genotypes was functionally assessed by IFN-γ stimulation of colon carcinoma cell lines (N = 10), followed by analyses of mRNA expression of HLA class I, TAP1, TAP2, and LMP7, with real-time PCR. Whereas induction of HLA-B, TAP1, and TAP2 was comparable in all cell lines, transcript amounts of LMP7-Q increased 10-fold, but of LMP7-K only 3.8-fold. This correlated with a reduced transcript stability of LMP7-K (t½ ≈ 7 minutes) compared with LMP7-Q (t½ ≈ 33 minutes). In addition, LMP7-Q/Q colon carcinoma cells increased (the peptide based) HLA class I surface expression significantly after IFN-γ stimulation, whereas LMP7-Q/K and LMP7-K/K carcinoma cells showed minimal (<20%) changes. These results suggest that the presence of LMP7-K can reduce the formation of immunoproteasomes and thus peptide processing, followed by reduced peptide–HLA presentation, a crucial factor in the immune response against cancer. Cancer Res; 71(23); 7145–54. ©2011 AACR.
Data from Annexin 1 Induced by Anti-Inflammatory Drugs Binds to NF-κB and Inhibits Its Activation: Anticancer Effects In vitro and In vivo
Authors: Zhang Zhiquan , Huang Liqun , Zhao Wenping , Rigas Basil
Published: March 2024

Abstract
Annexin A1 (ANXA1), a mediator of the anti-inflammatory action of glucocorticoids, is important in cancer development and progression, whereas NF-κB regulates multiple cellular phenomena, some of them associated with inflammation and cancer. We showed that glucocorticoids and chemopreventive modified nonsteroidal anti-inflammatory drugs, such as nitric oxide–donating aspirin (NO-ASA) and phospho-aspirin, induced ANXA1 in cultured human colon and pancreatic cancer cells. ANXA1 associated with NF-κB and suppressed its transcriptional activity by preventing NF-κB binding to DNA. The induction of ANXA1 by glucocorticoids was proportional to their anti-inflammatory potency, as was the suppression of NF-κB activity, which was accompanied by enhanced apoptosis and inhibition of cell growth mediated by changes in NF-κB–dependent cell signaling. The proposed novel mechanism was operational in the intestinal mucosa of mice treated with dexamethasone or NO-ASA. ANXA1-based oligopeptides displayed the same effects as ANXA1 on NF-κB. One such tripeptide (Gln-Ala-Trp) administered to nude mice inhibited the growth of SW480 human colon cancer xenografts by 58% compared with control (P < 0.01). Our findings reveal that ANXA1 is an inducible endogenous inhibitor of NF-κB in human cancer cells and mice, provide a novel molecular mechanism for the action of anti-inflammatory agents, and suggest the possibility of mechanism-driven drug development. Cancer Res; 70(6); 2379–88