bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Serine/Arginine Protein–Specific Kinase 2 Promotes Leukemia Cell Proliferation by Phosphorylating Acinus and Regulating Cyclin A1
Authors: Jang Sung-Wuk , Yang Seung-ju , Ehlén Åsa , Dong Shaozhong , Khoury Hanna , Chen Jing , Persson Jenny L. , Ye Keqiang
Published: March 2023

Abstract
Serine/arginine (SR) protein–specific kinase (SRPK), a family of cell cycle–regulated protein kinases, phosphorylate SR domain–containing proteins in nuclear speckles and mediate the pre-mRNA splicing. However, the physiologic roles of this event in cell cycle are incompletely understood. Here, we show that SRPK2 binds and phosphorylates acinus, an SR protein essential for RNA splicing, and redistributes it from the nuclear speckles to the nucleoplasm, resulting in cyclin A1 but not A2 up-regulation. Acinus S422D, an SRPK2 phosphorylation mimetic, enhances cyclin A1 transcription, whereas acinus S422A, an unphosphorylatable mutant, blocks the stimulatory effect of SRPK2. Ablation of acinus or SRPK2 abrogates cyclin A1 expression in leukemia cells and arrest cells at G1 phase. Overexpression of acinus or SRPK2 increases leukemia cell proliferation. Furthermore, both SRPK2 and acinus are overexpressed in some human acute myelogenous leukemia patients and correlate with elevated cyclin A1 expression levels, fitting with the oncogenic activity of cyclin A1 in leukemia. Thus, our findings establish a molecular mechanism by which SR splicing machinery regulates cell cycle and contributes to leukemia tumorigenesis. [Cancer Res 2008;68(12):4559–70]
Data from Ionizing Radiation Predisposes Nonmalignant Human Mammary Epithelial Cells to Undergo Transforming Growth Factor β–Induced Epithelial to Mesenchymal Transition
Authors: Andarawewa Kumari L. , Erickson Anna C. , Chou William S. , Costes Sylvain V. , Gascard Philippe , Mott Joni D. , Bissell Mina J. , Barcellos-Hoff Mary Helen
Published: March 2023

Abstract
Transforming growth factor β1 (TGFβ) is a tumor suppressor during the initial stage of tumorigenesis, but it can switch to a tumor promoter during neoplastic progression. Ionizing radiation (IR), both a carcinogen and a therapeutic agent, induces TGFβ activation in vivo. We now show that IR sensitizes human mammary epithelial cells (HMEC) to undergo TGFβ-mediated epithelial to mesenchymal transition (EMT). Nonmalignant HMEC (MCF10A, HMT3522 S1, and 184v) were irradiated with 2 Gy shortly after attachment in monolayer culture or treated with a low concentration of TGFβ (0.4 ng/mL) or double treated. All double-treated (IR + TGFβ) HMEC underwent a morphologic shift from cuboidal to spindle shaped. This phenotype was accompanied by a decreased expression of epithelial markers E-cadherin, β-catenin, and ZO-1, remodeling of the actin cytoskeleton, and increased expression of mesenchymal markers N-cadherin, fibronectin, and vimentin. Furthermore, double treatment increased cell motility, promoted invasion, and disrupted acinar morphogenesis of cells subsequently plated in Matrigel. Neither radiation nor TGFβ alone elicited EMT, although IR increased chronic TGFβ signaling and activity. Gene expression profiling revealed that double-treated cells exhibit a specific 10-gene signature associated with Erk/mitogen-activated protein kinase (MAPK) signaling. We hypothesized that IR-induced MAPK activation primes nonmalignant HMEC to undergo TGFβ-mediated EMT. Consistent with this, Erk phosphorylation was transiently induced by irradiation and persisted in irradiated cells treated with TGFβ, and treatment with U0126, a MAP/Erk kinase (MEK) inhibitor, blocked the EMT phenotype. Together, these data show that the interactions between radiation-induced signaling pathways elicit heritable phenotypes that could contribute to neoplastic progression. [Cancer Res 2007;67(18):8662–70]
Data from Activator Protein-1 Transcription Factors Are Associated with Progression and Recurrence of Prostate Cancer
Authors: Ouyang Xuesong , Jessen Walter J. , Al-Ahmadie Hikmat , Serio Angel M. , Lin Yong , Shih Weichung-Joseph , Reuter Victor E. , Scardino Peter T. , Shen Michael M. , Aronow Bruce J. , Vickers Andrew J. , Gerald William L. , Abate-Shen Cory
Published: March 2023

Abstract
To identify biomarkers that discriminate the aggressive forms of prostate cancer, we performed gene expression profiling of prostate tumors using a genetically engineered mouse model that recapitulates the stages of human prostate cancer, namely Nkx3.1; Pten mutant mice. We observed a significant deregulation of the epidermal growth factor and mitogen-activated protein kinase (MAPK) signaling pathways, as well as their major downstream effectors—the activator protein-1 transcription factors c-Fos and c-Jun. Forced expression of c-Fos and c-Jun in prostate cancer cells promotes tumorigenicity and results in activation of extracellular signal-regulated kinase (Erk) MAPK signaling. In human prostate cancer, up-regulation of c-Fos and c-Jun proteins occurs in advanced disease and is correlated with Erk MAPK pathway activation, whereas high levels of c-Jun expression are associated with disease recurrence. Our analyses reveal a hitherto unappreciated role for AP-1 transcription factors in prostate cancer progression and identify c-Jun as a marker of high-risk prostate cancer. This study provides a striking example of how accurate mouse models can provide insights on molecular processes involved in progression and recurrence of human cancer. [Cancer Res 2008;68(7):2132–44]
Data from The SIL Gene Is Essential for Mitotic Entry and Survival of Cancer Cells
Authors: Erez Ayelet , Castiel Asher , Trakhtenbrot Luba , Perelman Marina , Rosenthal Esther , Goldstein Itamar , Stettner Noa , Harmelin Alon , Eldar-Finkelman Hagit , Campaner Stefano , Kirsch Ilan , Izraeli Shai
Published: March 2023

Abstract
Although mitosis is a general physiologic process, cancer cells are unusually sensitive to mitotic inhibitors. Therefore, there is an interest in the identification of novel mitotic inhibitors. Here, we report the novel discovery of the SIL gene as a regulator of mitotic entry and cell survival. The SIL gene was cloned from leukemia-associated chromosomal translocation. It encodes a cytosolic protein with an unknown function and no homology to known proteins. Previously, we observed an increased expression of SIL in multiple cancers that correlated with the expression of mitotic spindle checkpoint genes and with increased metastatic potential. Here, we show that SIL is important for the transition from the G2 to the M phases of the cell cycle. Inducible knockdown of SIL in cancer cells in vitro delayed entrance into mitosis, decreased activation of the CDK1 (CDC2)-cyclin B complex, and induced apoptosis in a p53-independent manner. SIL is also essential for the growth of tumor explants in mice. Thus, SIL is required for mitotic entry and cancer cell survival. Because increased expression of SIL has been noted in multiple types of cancers and correlates with metastatic spread, it may be a suitable target for novel anticancer therapy. [Cancer Res 2007;67(9):4022–7]
Data from Enhanced Activation of Human Dendritic Cells by Inducible CD40 and Toll-like Receptor-4 Ligation
Authors: Lapteva Natalia , Seethammagari Mamatha R. , Hanks Brent A. , Jiang Jianghong , Levitt Jonathan M. , Slawin Kevin M. , Spencer David M.
Published: March 2023

Abstract
Despite the potency of dendritic cells (DC) as antigen-presenting cells for priming adaptive immunity, DC-based cancer vaccines have been largely insufficient to effectively reduce tumor burden or prevent tumor progression in most patients. To enhance DC-based vaccines, we used the combination of a synthetic ligand-inducible CD40 receptor (iCD40) along with Toll-like receptor-4 (TLR-4) ligation in human monocyte-derived DCs. The iCD40 receptor permits targeted, reversible activation of CD40 in vivo, potentially bypassing the essential role of CD4+ T cells for activation of DCs. As a rigorous preclinical study of this approach, we evaluated key parameters of DC activation and function. Whereas neither iCD40 nor TLR-4 signaling alone led to high levels of interleukin (IL)-12p70 and IL-6, using iCD40 in combination with lipopolysaccharide (LPS) or monophosphoryl lipid A led to strongly synergistic production of both. Furthermore, this approach led to high expression of DC maturation markers, epitope-specific CTL and T helper 1 responses, as well as DC migration in vitro and in vivo. Moreover, use of iCD40-modified and LPS-stimulated DCs led to targeted expansion of autologous T cells against tumor-associated antigens, including prostate-specific membrane antigen, and elimination of preestablished tumors, supporting this technology as a potent strategy for DC-based cancer immunotherapy. [Cancer Res 2007;67(21):10528–10]
Data from Gene Expression Analysis of Angioimmunoblastic Lymphoma Indicates Derivation from T Follicular Helper Cells and Vascular Endothelial Growth Factor Deregulation
Authors: Piccaluga Pier Paolo , Agostinelli Claudio , Califano Andrea , Carbone Antonino , Fantoni Luca , Ferrari Sergio , Gazzola Anna , Gloghini Annunziata , Righi Simona , Rossi Maura , Tagliafico Enrico , Zinzani Pier Luigi , Zupo Simonetta , Baccarani Michele , Pileri Stefano A.
Published: March 2023

Abstract
Angioimmunoblastic lymphoma (AILT) is the second most common subtype of peripheral T-cell lymphoma (PTCL) and is characterized by dismal prognosis. Thus far, only a few studies have dealt with its molecular pathogenesis. We performed gene expression profile (GEP) analysis of six AILT, six anaplastic large cell lymphomas (ALCL), 28 PTCL-unspecified (PTCL/U), and 20 samples of normal T lymphocytes (including CD4+, CD8+, and activated and resting subpopulations), aiming to (a) assess the relationship of AILT with other PTCLs, (b) establish the relationship between AILT and normal T-cell subsets, and (c) recognize the cellular programs deregulated in AILT possibly looking for novel potential therapeutic targets. First, we found that AILT and other PTCLs have rather similar GEP, possibly sharing common oncogenic pathways. Second, we found that AILTs are closer to activated CD4+, rather than to resting or CD8+ lymphocytes. Furthermore, we found that the molecular signature of follicular T helper cells was significantly overexpressed in AILT, reinforcing the idea that AILT may arise from such cellular counterpart. Finally, we identified several genes deregulated in AILT, including PDGFRA, REL, and VEGF. The expression of several molecules was then studied by immunohistochemistry on tissue microarrays containing 45 independent AILT cases. Notably, we found that the vascular endothelial growth factor (VEGF) was expressed not only by reactive cells, but also by neoplastic cells, and that nuclear factor-κB (NF-κB) activation is uncommon in AILT, as suggested by frequent exclusively cytoplasmic c-REL localization. Our study provides new relevant information on AILT biology and new candidates for possible therapeutic targets such as PDGFRA (platelet-derived growth factor α) and VEGF. [Cancer Res 2007;67(22):10703–10]
Data from Combined Lysophosphatidic Acid/Platelet-Derived Growth Factor Signaling Triggers Glioma Cell Migration in a Tenascin-C Microenvironment
Authors: Lange Katrin , Kammerer Martial , Saupe Falk , Hegi Monika E. , Grotegut Stefan , Fluri Erika , Orend Gertraud
Published: March 2023

Abstract
The antiadhesive extracellular matrix molecule tenascin-C abrogates cell spreading on fibronectin through competitive inhibition of syndecan-4, thereby preventing focal adhesion kinase (FAK) activation and triggering enhanced proteolytic degradation of both RhoA and tropomyosin 1 (TM1). Here, we show that simultaneous signaling by lysophosphatidic acid (LPA) and platelet-derived growth factor (PDGF) initiates glioma cell spreading and migration through syndecan-4–independent activation of paxillin and FAK and by stabilizing expression of RhoA, TM1, TM2, and TM3. By using gene silencing methods, we show that paxillin, TM1, TM2, and TM3 are essential for LPA/PDGF-induced cell spreading on a fibronectin/tenascin-C (FN/TN) substratum. LPA/PDGF-induced cell spreading and migration on FN/TN depends on phosphatidylinositol 3-kinase, RhoKinase, and mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1/2 but is independent of phospholipase C and Jun kinase. RNA microarray data reveal expression of tenascin-C, PDGFs, LPA, and the respective receptors in several types of cancer, suggesting that the TN/LPA/PDGF axis exists in malignant tumors. These findings may in turn be relevant for diagnostic or therapeutic applications targeting cancer. [Cancer Res 2008;68(17):6942–52]
Data from Genetic Variation at the CYP19A1 Locus Predicts Circulating Estrogen Levels but not Breast Cancer Risk in Postmenopausal Women
Authors: Haiman Christopher A. , Dossus Laure , Setiawan V. Wendy , Stram Daniel O. , Dunning Alison M. , Thomas Gilles , Thun Michael J. , Albanes Demetrius , Altshuler David , Ardanaz Eva , Boeing Heiner , Buring Julie , Burtt Noël , Calle Eugenia E. , Chanock Stephen , Clavel-Chapelon Françoise , Colditz Graham A. , Cox David G. , Feigelson Heather Spencer , Hankinson Susan E. , Hayes Richard B. , Henderson Brian E. , Hirschhorn Joel N. , Hoover Robert , Hunter David J. , Kaaks Rudolf , Kolonel Laurence N. , Le Marchand Loïc , Lenner Per , Lund Eiliv , Panico Salvatore , Peeters Petra H. , Pike Malcolm C. , Riboli Elio , Tjonneland Anne , Travis Ruth , Trichopoulos Dimitrios , Wacholder Sholom , Ziegler Regina G.
Published: March 2023

Abstract
The CYP19A1 gene encodes the enzyme aromatase, which is responsible for the final step in the biosynthesis of estrogens. In this study, we used a systematic two-step approach that included gene resequencing and a haplotype-based analysis to comprehensively survey common genetic variation across the CYP19A1 locus in relation to circulating postmenopausal steroid hormone levels and breast cancer risk. This study was conducted among 5,356 invasive breast cancer cases and 7,129 controls comprised primarily of White women of European descent drawn from five large prospective cohorts within the National Cancer Institute Breast and Prostate Cancer Cohort Consortium. A high-density single-nucleotide polymorphism (SNP) map of 103 common SNPs (≥5% frequency) was used to identify the linkage disequilibrium and haplotype patterns across the CYP19A1 locus, and 19 haplotype-tagging SNPs were selected to provide high predictability of the common haplotype patterns. We found haplotype-tagging SNPs and common haplotypes spanning the coding and proximal 5′ region of CYP19A1 to be significantly associated with a 10% to 20% increase in endogenous estrogen levels in postmenopausal women [effect per copy of the two-SNP haplotype rs749292-rs727479 (A-A) versus noncarriers; P = 4.4 × 10−15]. No significant associations were observed, however, with these SNPs or common haplotypes and breast cancer risk. Thus, although genetic variation in CYP19A1 produces measurable differences in estrogen levels among postmenopausal women, the magnitude of the change was insufficient to contribute detectably to breast cancer. [Cancer Res 2007;67(5):1893–7]
Data from Mammalian Target of Rapamycin Activation Impairs Hepatocytic Differentiation and Targets Genes Moderating Lipid Homeostasis and Hepatocellular Growth
Authors: Parent Romain , Kolippakkam Deepak , Booth Garrett , Beretta Laura
Published: March 2023

Abstract
The mammalian target of rapamycin (mTOR) pathway, a major regulator of translation, is frequently activated in hepatocellular carcinomas. We investigated the effects of mTOR activation in the human HepaRG cells, which possess potent hepatocytic differentiation capability. Differentiation of HepaRG cells into functional and polarized hepatocyte-like cells correlated with a decrease in mTOR and Akt activities. Stable cell lines expressing an activated mutant of mTOR were generated. Sustained activation of mTOR impaired the hepatocytic differentiation capability of these cells as shown by impaired formation of bile canaliculi, absence of polarity, and reduced secretion of α1-antitrypsin. An inhibitor of mTOR, rapamycin, was able to revert this phenotype. Furthermore, increased mTOR activity in HepaRG cells resulted in their resistance to the antiproliferative effects of transforming growth factor-β1. Profiling of polysome-bound transcripts indicated that activated mTOR specifically targeted genes posttranscriptionally regulated on hepatocytic differentiation. Three major biological networks targeted by activated mTOR were identified: (a) cell death associated with tumor necrosis factor superfamily members, IFNs and caspases; (b) lipid homeostasis associated with the transcription factors PPARα, PPARδ, and retinoid X receptor β; and (c) liver development associated with CCAAT/enhancer binding protein α and hepatic mitogens. In conclusion, increased mTOR activity conferred a preneoplastic phenotype to the HepaRG cells by altering the translation of genes vital for establishing normal hepatic energy homeostasis and moderating hepatocellular growth. [Cancer Res 2007;67(9):4337–45]
Data from Capsiate, a Nonpungent Capsaicin-Like Compound, Inhibits Angiogenesis and Vascular Permeability via a Direct Inhibition of Src Kinase Activity
Authors: Pyun Bo-Jeong , Choi Sun , Lee Yoonji , Kim Tae-Woong , Min Jeong-Ki , Kim Yonghak , Kim Byung-Dong , Kim Jeong-Han , Kim Tae-Yoon , Kim Young-Myeong , Kwon Young-Guen
Published: March 2023

Abstract
Capsiate, a nonpungent capsaicin analogue, and its dihydroderivative dihydrocapsiate are the major capsaicinoids of the nonpungent red pepper cultivar CH-19 Sweet. In this study, we report the biological actions and underlying molecular mechanisms of capsiate on angiogenesis and vascular permeability. In vitro, capsiate and dihydrocapsiate inhibited vascular endothelial growth factor (VEGF)–induced proliferation, chemotactic motility, and capillary-like tube formation of primary cultured human endothelial cells. They also inhibited sprouting of endothelial cells in the rat aorta and formation of new blood vessels in the mouse Matrigel plug assay in response to VEGF. Moreover, both compounds blocked VEGF-induced endothelial permeability and loss of vascular endothelial (VE)–cadherin–facilitated endothelial cell-cell junctions. Importantly, capsiate suppressed VEGF-induced activation of Src kinase and phosphorylation of its downstream substrates, such as p125FAK and VE-cadherin, without affecting autophosphorylation of the VEGF receptor KDR/Flk-1. In vitro kinase assay and molecular modeling studies revealed that capsiate inhibits Src kinase activity via its preferential docking to the ATP-binding site of Src kinase. Taken together, these results suggest that capsiate could be useful for blocking pathologic angiogenesis and vascular permeability caused by VEGF. [Cancer Res 2008;68(1):227–35]
Data from Reversible Dysfunction of Wild-Type p53 following Homeodomain-Interacting Protein Kinase-2 Knockdown
Authors: Puca Rosa , Nardinocchi Lavinia , Gal Hilah , Rechavi Gideon , Amariglio Ninette , Domany Eytan , Notterman Daniel A. , Scarsella Marco , Leonetti Carlo , Sacchi Ada , Blandino Giovanni , Givol David , D'Orazi Gabriella
Published: March 2023

Abstract
About half of cancers sustain mutations in the TP53 gene, whereas the other half maintain a wild-type p53 (wtp53) but may compromise the p53 response because of other alterations. Homeodomain-interacting protein kinase-2 (HIPK2) is a positive regulator of p53 oncosuppressor function. Here, we show, by microarray analysis, that wtp53 lost the target gene activation following stable knockdown of HIPK2 (HIPK2i) in colon cancer cell line. Our data show that the stable knockdown of HIPK2 led to wtp53 misfolding, as detected by p53 immunoprecipitation with conformation-specific antibodies, and that p53 protein misfolding impaired p53 DNA binding and transcription of target genes. We present evidence that zinc supplementation to HIPK2i cells increased p53 reactivity to conformation-sensitive PAb1620 (wild-type conformation) antibody and restored p53 sequence-specific DNA binding in vivo and transcription of target genes in response to Adriamycin treatment. Finally, combination of zinc and Adriamycin suppressed tumor growth in vivo and activated misfolded p53 that induced its target genes in nude mice tumor xenografts derived from HIPK2i cells. Bioinformatics analysis of microarray data from colon cancer patients showed significant association of poor survival with low HIPK2 expression only in tumors expressing wtp53. These results show a critical role of HIPK2 in maintaining the transactivation activity of wtp53 and further suggest that low expression of HIPK2 may impair the p53 function in tumors harboring wtp53. [Cancer Res 2008;68(10):3707–13]
Data from Tumor Necrosis Factor-α Promotes Malignant Pleural Effusion
Authors: Stathopoulos Georgios T. , Kollintza Androniki , Moschos Charalampos , Psallidas Ioannis , Sherrill Taylor P. , Pitsinos Emmanuel N. , Vassiliou Spyridoula , Karatza Marilena , Papiris Spyros A. , Graf Daniel , Orphanidou Dora , Light Richard W. , Roussos Charis , Blackwell Timothy S. , Kalomenidis Ioannis
Published: March 2023

Abstract
Tumor necrosis factor (TNF)-α is present in the microenvironment of human tumors, including malignant pleural effusion (MPE). Although the cytokine is produced in the pleural cavity by both tumor and host cells, its effects on MPE formation are unknown. In these studies, we sought to determine the role of TNF-α in the pathogenesis of MPE and to assess the therapeutic effects of its neutralization in a preclinical model. For this, MPEs were generated in immunocompetent mice using intrapleural injection of mouse lung adenocarcinoma cells. The roles of tumor- and host-derived TNF-α were assessed using combined experimentation with TNF-α gene–deficient mice and in vivo TNF-α neutralization. To expand the scope of preclinical data, TNF-α and vascular endothelial growth factor (VEGF) expression were determined in human cancer cell lines and human MPE. In the MPE model, TNF-α of host and tumor origin was present. TNF-α neutralization significantly limited tumor dissemination, effusion formation, vascular hyperpermeability, TNF-α and VEGF expression, and angiogenesis, thereby improving survival. In contrast, these variables were not different between TNF-α gene–sufficient and TNF-α gene–deficient mice. In mouse cancer cells, TNF-α functioned via nuclear factor-κB– and neutral sphingomyelinase–dependent pathways to induce TNF-α and VEGF, respectively. These results were recapitulated in human cancer cells, and a correlation was detected between TNF-α and VEGF content of human MPE. We conclude that tumor-derived TNF-α is important in the development of MPE in mice, and provide preclinical evidence supporting the efficacy of TNF-α blockade against malignant pleural disease. [Cancer Res 2007;67(20):9825–34]
Data from An Orally Available Small-Molecule Inhibitor of c-Met, PF-2341066, Exhibits Cytoreductive Antitumor Efficacy through Antiproliferative and Antiangiogenic Mechanisms
Authors: Zou Helen Y. , Li Qiuhua , Lee Joseph H. , Arango Maria E. , McDonnell Scott R. , Yamazaki Shinji , Koudriakova Tatiana B. , Alton Gordon , Cui Jingrong J. , Kung Pei-Pei , Nambu Mitchell D. , Los Gerrit , Bender Steven L. , Mroczkowski Barbara , Christensen James G.
Published: March 2023

Abstract
The c-Met receptor tyrosine kinase and its ligand, hepatocyte growth factor (HGF), have been implicated in the progression of several human cancers and are attractive therapeutic targets. PF-2341066 was identified as a potent, orally bioavailable, ATP-competitive small-molecule inhibitor of the catalytic activity of c-Met kinase. PF-2341066 was selective for c-Met (and anaplastic lymphoma kinase) compared with a panel of >120 diverse tyrosine and serine-threonine kinases. PF-2341066 potently inhibited c-Met phosphorylation and c-Met–dependent proliferation, migration, or invasion of human tumor cells in vitro (IC50 values, 5–20 nmol/L). In addition, PF-2341066 potently inhibited HGF-stimulated endothelial cell survival or invasion and serum-stimulated tubulogenesis in vitro, suggesting that this agent also exhibits antiangiogenic properties. PF-2341066 showed efficacy at well-tolerated doses, including marked cytoreductive antitumor activity, in several tumor models that expressed activated c-Met. The antitumor efficacy of PF-2341066 was dose dependent and showed a strong correlation to inhibition of c-Met phosphorylation in vivo. Near-maximal inhibition of c-Met activity for the full dosing interval was necessary to maximize the efficacy of PF-2341066. Additional mechanism-of-action studies showed dose-dependent inhibition of c-Met–dependent signal transduction, tumor cell proliferation (Ki67), induction of apoptosis (caspase-3), and reduction of microvessel density (CD31). These results indicated that the antitumor activity of PF-2341066 may be mediated by direct effects on tumor cell growth or survival as well as antiangiogenic mechanisms. Collectively, these results show the therapeutic potential of targeting c-Met with selective small-molecule inhibitors for the treatment of human cancers. [Cancer Res 2007;67(9):4408–17]
Data from Pirh2 Promotes Ubiquitin-Dependent Degradation of the Cyclin-Dependent Kinase Inhibitor p27Kip1
Authors: Hattori Takayuki , Isobe Tomoyasu , Abe Kenji , Kikuchi Hirotoshi , Kitagawa Kyoko , Oda Toshiaki , Uchida Chiharu , Kitagawa Masatoshi
Published: March 2023

Abstract
The cyclin-dependent kinase inhibitor p27Kip1 is degraded in late G1 phase by the ubiquitin-proteasome pathway, allowing cells to enter S phase. Due to accelerated degradation of p27Kip1, various human cancers express low levels of p27Kip1 associated with poor prognosis. S-phase kinase–associated protein 2, the F-box protein component of an SCF ubiquitin ligase complex, is implicated in degradation of p27Kip1 during S-G2 phases. Recently, Kip1 ubiquitination–promoting complex has been reported as another ubiquitin ligase that targets cytoplasmic p27Kip1 exported from the nucleus in G0-G1 phases. Here, we identified a RING-H2–type ubiquitin ligase, Pirh2, as a p27Kip1-interacting protein. Endogenous Pirh2 physically interacted with endogenous p27Kip1 in mammalian cells. Pirh2 directly ubiquitinated p27Kip1 in an intact RING finger domain-dependent manner in vivo, as well as in vitro. Ablation of endogenous Pirh2 by small interfering RNA increased the steady-state level of p27Kip1 and decelerated p27Kip1 turnover. Depletion of Pirh2 induced accumulation of p27Kip1 in both the nucleus and cytoplasm. Pirh2 expression was induced from late G1-S phase, whereas p27Kip1 was decreased in synchronization with accumulation of Pirh2. Furthermore, reduction of Pirh2 resulted in an impairment of p27Kip1 degradation and an inhibition of cell cycle progression at G1-S transition in a p53-independent manner. Overall, the results indicate that Pirh2 acts as a negative regulator of p27Kip1 function by promoting ubiquitin-dependent proteasomal degradation. [Cancer Res 2007;67(22):10789–95]
Data from Regulation of Breast Cancer Response to Chemotherapy by Fibulin-1
Authors: Pupa Serenella M. , Giuffré Sarah , Castiglioni Fabio , Bertola Lorenzo , Cantú Marco , Bongarzone Italia , Baldassari Paola , Mortarini Roberta , Argraves W. Scott , Anichini Andrea , Menard Sylvie , Tagliabue Elda
Published: March 2023

Abstract
Doxorubicin treatment was found to augment the expression of the extracellular matrix (ECM) protein fibulin-1 in cultured human breast cancer cell lines and in MDA-MB-361 tumors grown in athymic mice. Doxorubicin was also found to augment tumor expression of the fibulin-1–binding proteins fibronectin and laminin-1. Growth of breast cancer cell lines on Matrigel, an ECM extract containing fibulin-1 and laminin-1, resulted in lower levels of doxorubicin-induced apoptosis as compared with controls. Moreover, tumors formed by injection of athymic mice with MDA-MB-361 cells mixed with Matrigel were significantly more doxorubicin resistant and displayed lower levels of apoptosis compared with those that formed in the absence of Matrigel. Monoclonal antibodies against fibulin-1 reversed Matrigel-dependent doxorubicin resistance. Furthermore, small interfering RNA–mediated suppression of fibulin-1 expression in breast cancer cells resulted in a 10-fold increase in doxorubicin sensitivity as compared with control cells. Together, these findings point to a role for fibulin-1 in breast cancer chemoresistance. [Cancer Res 2007;67(9):4271–7]
Data from Epidermal Growth Factor Receptor Mutants from Human Lung Cancers Exhibit Enhanced Catalytic Activity and Increased Sensitivity to Gefitinib
Authors: Mulloy Roseann , Ferrand Audrey , Kim Youngjoo , Sordella Raffaella , Bell Daphne W. , Haber Daniel A. , Anderson Karen S. , Settleman Jeffrey
Published: March 2023

Abstract
Somatic mutations within the epidermal growth factor receptor (EGFR) kinase domain are detected in 10% to 30% of human non–small cell lung cancers and are correlated with striking clinical responses in a subset of patients treated with EGFR kinase inhibitors, such as gefitinib and erlotinib. Cell-based studies suggest that these mutant EGFRs promote increased autophosphorylating activity on a subset of EGFR COOH-terminal tyrosines and the consequent engagement of a subset of downstream effectors. Because EGFR function is regulated at multiple levels in vivo, and it is therefore difficult to assess the direct consequences of these mutations on EGFR enzyme function, we measured EGFR catalytic activity in in vitro kinase assays using purified recombinant proteins corresponding to the cytoplasmic domain of wild-type and two frequently detected EGFR mutants (DelL747-P753insS and L858R). Both mutants exhibit substantially increased autophosphorylating activity relative to wild-type EGFR, and they exhibit distinct reaction kinetics. In addition, the mutant kinases are more sensitive to kinase inhibition by gefitinib, which seems to reflect their increased drug affinity. These findings suggest that the altered signaling properties and drug sensitivity of these EGFR mutants that have been observed in vivo largely result from differences in the catalytic properties of the kinase. In addition, we find that the T790M secondary “drug resistance mutation” of EGFR, which frequently arises in relapsed patients that initially responded to treatment, confers enhanced kinase activity to primary activating EGFR alleles and may, therefore, be oncogenic in some contexts. [Cancer Res 2007;67(5):2325–30]
Data from Crucial Role of Phospholipase Cε in Skin Inflammation Induced by Tumor-Promoting Phorbol Ester
Authors: Ikuta Shuzo , Edamatsu Hironori , Li Mingzhen , Hu Lizhi , Kataoka Tohru
Published: March 2023

Abstract
In two-stage skin chemical carcinogenesis, phorbol ester 12-O-tetradecanoylphorbol-13-acetate (TPA) acts as a promoter essential for clonal expansion of the initiated cells carrying the activated ras oncogenes. Although protein kinase C (PKC) isozymes are the main targets of TPA, their role in tumor promotion remains controversial. We previously reported that mice lacking a Ras/Rap effector phospholipase Cε (PLCε−/− mice) exhibited marked resistance to tumor formation in the two-stage skin carcinogenesis. PLCε−/− mice also failed to exhibit basal layer cell proliferation and epidermal hyperplasia induced by TPA, suggesting a role of PLCε in tumor promotion. Here, we show that PLCε−/− mice exhibit resistance to TPA-induced skin inflammation as assessed by reduction in edema, granulocyte infiltration, and expression of a proinflammatory cytokine, interleukin-1α (IL-1α). On the other hand, the proliferative potentials of keratinocytes or dermal fibroblasts in culture remain unaffected by the PLCε background, suggesting that the PLCε's role in tumor promotion may be ascribed to augmentation of inflammatory responses. In dermal fibroblast primary culture, TPA can induce activation of the PLCε lipase activity, which leads to the induction of IL-1α expression. Experiments using small interfering RNA–mediated knockdown indicate that this activation is mediated by Rap1, which is activated by a TPA-responsive guanine nucleotide exchange factor RasGRP3. Moreover, TPA-induced activation of Rap1 and PLCε is inhibited by a PKC inhibitor GF109203X, indicating a crucial role of PKC in signaling from TPA to PLCε. These results imply that two TPA targets, RasGRP3 and PKC, are involved in TPA-induced inflammation through PLCε activation, leading to tumor promotion. [Cancer Res 2008;68(1):64–72]
Data from Systemic Overexpression of Angiopoietin-2 Promotes Tumor Microvessel Regression and Inhibits Angiogenesis and Tumor Growth
Authors: Cao Yiting , Sonveaux Pierre , Liu Shanling , Zhao Yulin , Mi Jing , Clary Bryan M. , Li Chuan-Yuan , Kontos Christopher D. , Dewhirst Mark W.
Published: March 2023

Abstract
Angiopoietin-2 (Ang-2) is a conditional antagonist and agonist for the endothelium-specific Tie-2 receptor. Although endogenous Ang-2 cooperates with vascular endothelial growth factor (VEGF) to protect tumor endothelial cells, the effect on tumor vasculature of high levels of exogenous Ang-2 with different levels of VEGF has not been studied in detail. Here, we report that systemic overexpression of Ang-2 leads to unexpected massive tumor vessel regression within 24 h, even without concomitant inhibition of VEGF. By impairing pericyte coverage of the tumor vasculature, Ang-2 destabilizes the tumor vascular bed while improving perfusion in surviving tumor vessels. Ang-2 overexpression transiently exacerbates tumor hypoxia without affecting ATP levels. Although sustained systemic Ang-2 overexpression does not affect tumor hypoxia and proliferation, it significantly inhibits tumor angiogenesis, promotes tumor apoptosis, and suppresses tumor growth. The similar antitumoral, antiangiogenic efficacy of systemic overexpression of Ang-2, soluble VEGF receptor-1, and the combination of both suggests that concomitant VEGF inhibition is not required for Ang-2–induced tumor vessel regression and growth delay. This study shows the important roles of Ang-2–induced pericyte dropout during tumor vessel regression. It also reveals that elevated Ang-2 levels have profound pleiotropic effects on tumor vessel structure, perfusion, oxygenation, and apoptosis. [Cancer Res 2007;67(8):3835–44]
Data from Functional Neoangiogenesis Imaging of Genetically Engineered Mouse Prostate Cancer Using Three-Dimensional Power Doppler Ultrasound
Authors: Xuan Jim W. , Bygrave Michael , Jiang Hongyi , Valiyeva Fatma , Dunmore-Buyze Joy , Holdsworth David W. , Izawa Jonathan I. , Bauman Glenn , Moussa Madeleine , Winter Scott F. , Greenberg Norman M. , Chin Joseph L. , Drangova Maria , Fenster Aaron , Lacefield James C.
Published: March 2023

Abstract
We report the first application of high-frequency three-dimensional power Doppler ultrasound imaging in a genetically engineered mouse (GEM) prostate cancer model. We show that the technology sensitively and specifically depicts functional neoangiogenic blood flow because little or no flow is measurable in normal prostate tissue or tumors smaller than 2–3 mm diameter, the neoangiogenesis “switch-on” size. Vascular structures depicted by power Doppler were verified using Microfil-enhanced micro-computed tomography (micro-CT) and by correlation with microvessel distributions measured by immunohistochemistry and enhanced vascularity visualized by confocal microscopy in two GEM models [transgenic adenocarcinoma of the mouse prostate (TRAMP) and PSP94 gene-directed transgenic mouse adenocarcinoma of the prostate (PSP-TGMAP)]. Four distinct phases of neoangiogenesis in cancer development were observed, specifically, (a) an early latent phase; (b) establishment of a peripheral capsular vascular structure as a neoangiogenesis initiation site; (c) a peak in tumor vascularity that occurs before aggressive tumor growth; and (d) rapid tumor growth accompanied by decreasing vascularity. Microsurgical interventions mimicking local delivery of antiangiogenesis drugs were done by ligating arteries upstream from feeder vessels branching to the prostate. Microsurgery produced an immediate reduction of tumor blood flow, and flow remained low from 1 h to 2 weeks or longer after treatment. Power Doppler, in conjunction with micro-CT, showed that the tumors recruit secondary blood supplies from nearby vessels, which likely accounts for the continued growth of the tumors after surgery. The microsurgical model represents an advanced angiogenic prostate cancer stage in GEM mice corresponding to clinically defined hormone-refractory prostate cancer. Three-dimensional power Doppler imaging is completely noninvasive and will facilitate basic and preclinical research on neoangiogenesis in live animal models. [Cancer Res 2007;67(6):2830–9]
Data from Caspase-8 Interacts with the p85 Subunit of Phosphatidylinositol 3-Kinase to Regulate Cell Adhesion and Motility
Authors: Senft Jamie , Helfer Brooke , Frisch Steven M.
Published: March 2023

Abstract
Cell migration plays an important role in tumor cell invasion and metastasis. Previously, we reported that caspase-8 contributes to cell migration and adhesion, a novel nonapoptotic function of an established apoptotic factor. Herein, we report that pro-caspase-8 is capable of restoring cell migration/adhesion to caspase-8-null cells, establishing the first biological function of a pro-caspase. The catalytic activity of caspase-8 was not required for cell motility. Stimulation of motility with epidermal growth factor induced the phosphorylation of caspase-8 on tyrosine-380 and the interaction of caspase-8 with the p85α subunit of phosphatidylinositol 3-kinase. Tyrosine-380 was required for the restoration of cell motility and cell adhesion in caspase-8-null cells, demonstrating the importance of the caspase-8–p85 interaction for these nonapoptotic functions. These results suggest that caspase-8 phosphorylation converts it from a proapoptotic factor to a cell motility factor that, through tyrosine-380, interacts with p85, an established cell migration component. [Cancer Res 2007;67(24):11505–9]
Data from Thermal Cycling Enhances the Accumulation of a Temperature-Sensitive Biopolymer in Solid Tumors
Authors: Dreher Matthew R. , Liu Wenge , Michelich Charles R. , Dewhirst Mark W. , Chilkoti Ashutosh
Published: March 2023

Abstract
The delivery of anticancer therapeutics to solid tumors remains a critical problem in the treatment of cancer. This study reports a new methodology to target a temperature-responsive macromolecular drug carrier, an elastin-like polypeptide (ELP) to solid tumors. Using a dorsal skin fold window chamber model and intravital laser scanning confocal microscopy, we show that the ELP forms micron-sized aggregates that adhere to the tumor vasculature only when tumors are heated to 41.5°C. Upon return to normothermia, the vascular particles dissolve into the plasma, increasing the vascular concentration, which drives more ELPs across the tumor blood vessel and significantly increases its extravascular accumulation. These observations suggested that thermal cycling of tumors would increase the exposure of tumor cells to ELP drug carriers. We investigated this hypothesis in this study by thermally cycling an implanted tumor in nude mice from body temperature to 41.5°C thrice within 1.5 h, and showed the repeated formation of adherent microparticles of ELP in the heated tumor vasculature in each thermal cycle. These results suggest that thermal cycling of tumors can be repeated multiple times to further increase the accumulation of a thermally responsive polymeric drug carrier in solid tumors over a single heat-cool cycle. More broadly, this study shows a new approach—tumor thermal cycling—to exploit stimuli-responsive polymers in vivo to target the tumor vasculature or extravascular compartment with high specificity. [Cancer Res 2007;67(9):4418–24]
Data from Targeting HER-2/neu in Early Breast Cancer Development Using Dendritic Cells with Staged Interleukin-12 Burst Secretion
Authors: Czerniecki Brian J. , Koski Gary K. , Koldovsky Ursula , Xu Shuwen , Cohen Peter A. , Mick Rosemarie , Nisenbaum Harvey , Pasha Terry , Xu Min , Fox Kevin R. , Weinstein Susan , Orel Susan G. , Vonderheide Robert , Coukos George , DeMichele Angela , Araujo Louis , Spitz Francis R. , Rosen Mark , Levine Bruce L. , June Carl , Zhang Paul J.
Published: March 2023

Abstract
Overexpression of HER-2/neu (c-erbB2) is associated with increased risk of recurrent disease in ductal carcinoma in situ (DCIS) and a poorer prognosis in node-positive breast cancer. We therefore examined the early immunotherapeutic targeting of HER-2/neu in DCIS. Before surgical resection, HER-2/neupos DCIS patients (n = 13) received 4 weekly vaccinations of dendritic cells pulsed with HER-2/neu HLA class I and II peptides. The vaccine dendritic cells were activated in vitro with IFN-γ and bacterial lipopolysaccharide to become highly polarized DC1-type dendritic cells that secrete high levels of interleukin-12p70 (IL-12p70). Intranodal delivery of dendritic cells supplied both antigenic stimulation and a synchronized preconditioned burst of IL-12p70 production directly to the anatomic site of T-cell sensitization. Before vaccination, many subjects possessed HER-2/neu–HLA-A2 tetramer-staining CD8pos T cells that expressed low levels of CD28 and high levels of the inhibitory B7 ligand CTLA-4, but this ratio inverted after vaccination. The vaccinated subjects also showed high rates of peptide-specific sensitization for both IFN-γ–secreting CD4pos (85%) and CD8pos (80%) T cells, with recognition of antigenically relevant breast cancer lines, accumulation of T and B lymphocytes in the breast, and induction of complement-dependent, tumor-lytic antibodies. Seven of 11 evaluable patients also showed markedly decreased HER-2/neu expression in surgical tumor specimens, often with measurable decreases in residual DCIS, suggesting an active process of “immunoediting” for HER-2/neu–expressing tumor cells following vaccination. DC1 vaccination strategies may therefore have potential for both the prevention and the treatment of early breast cancer. [Cancer Res 2007;67(4):1842–52]
Data from PF00299804, an Irreversible Pan-ERBB Inhibitor, Is Effective in Lung Cancer Models with EGFR and ERBB2 Mutations that Are Resistant to Gefitinib
Authors: Engelman Jeffrey A. , Zejnullahu Kreshnik , Gale Christopher-Michael , Lifshits Eugene , Gonzales Andrea J. , Shimamura Takeshi , Zhao Feng , Vincent Patrick W. , Naumov George N. , Bradner James E. , Althaus Irene W. , Gandhi Leena , Shapiro Geoffrey I. , Nelson James M. , Heymach John V. , Meyerson Matthew , Wong Kwok-Kin , Jänne Pasi A.
Published: March 2023

Abstract
Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors gefitinib and erlotinib are effective treatments for a subset of non–small cell lung cancers. In particular, cancers with specific EGFR-activating mutations seem to be the most sensitive to these agents. However, despite their initial response, such cancers almost invariably develop resistance. In 50% of such cancers, a secondary EGFR mutation, T790M, has been identified that renders gefitinib and erlotinib ineffective inhibitors of EGFR kinase activity. Thus, there is a clinical need to develop novel EGFR inhibitors that can effectively inactivate T790M-containing EGFR proteins. In this study, we evaluate the effectiveness of a novel compound, PF00299804, an irreversible pan-ERBB inhibitor. The results from these studies show that PF00299804 is a potent inhibitor of EGFR-activating mutations as well as the EGFR T790M resistance mutation both in vitro and in vivo. Additionally, PF00299804 is a highly effective inhibitor of both the wild-type ERBB2 and the gefitinib-resistant oncogenic ERBB2 mutation identified in lung cancers. These preclinical evaluations support further clinical development of PF00299804 for cancers with mutations and/or amplifications of ERBB family members. [Cancer Res 2007;67(24):11924–32]
Data from New Soft Alkylating Agents with Enhanced Cytotoxicity against Cancer Cells Resistant to Chemotherapeutics and Hypoxia
Authors: Patenaude Alexandre , Deschesnes Réna G. , Rousseau Jean L.C. , Petitclerc Éric , Lacroix Jacques , Côté Marie-France , C.-Gaudreault René
Published: March 2023

Abstract
Chloroethylureas (CEU) are soft alkylating agents that covalently bind to β-tubulin (βTAC) and affect microtubule polymerization dynamics. Herein, we report the identification of a CEU subset and its corresponding oxazolines, which induce cell growth inhibition, apoptosis, and microtubule disruption without alkylating β-tubulin (N-βTAC). Both βTAC and N-βTAC trigger the collapse of mitochondrial potential (ΔΨm) and modulate reactive oxygen species levels, following activation of intrinsic caspase-8 and caspase-9. Experiments using human fibrosarcoma HT1080 respiratory-deficient cells (ρ0) and uncoupler of the mitochondrial respiratory chain (MRC) showed that βTAC and N-βTAC impaired the MRC. ρ0 cells displayed an increased sensitivity toward N-βTAC as compared with ρ+ cells but, in contrast, were resistant to βTAC or classic chemotherapeutics, such as paclitaxel. Oxazoline-195 (OXA-195), an N-βTAC derivative, triggered massive swelling of isolated mitochondria. This effect was insensitive to cyclosporin A and to Bcl-2 addition. In contrast, adenine nucleotide translocator (ANT) antagonists, bongkrekic acid or atractyloside, diminished swelling induced by OXA-195. The antiproliferative activities of the N-βTACs CEU-025 and OXA-152 were markedly decreased in the presence of atractyloside. Conversely, pretreatment with cyclosporin A enhanced growth inhibition induced by βTAC and N-βTAC. One of the proteins alkylated by N-βTAC was identified as the voltage-dependent anion channel isoform-1, an ANT partner. Our results suggest that βTAC and N-βTAC, despite their common ability to affect the microtubule network, trigger different cytotoxic mechanisms in cancer cells. The role of mitochondria in these mechanisms and the potential of N-βTAC as a new therapeutic approach for targeting hypoxia-resistant cells are discussed. [Cancer Res 2007;67(5):2306–16]
Data from Huntingtin Interacting Protein 1 Is a Novel Brain Tumor Marker that Associates with Epidermal Growth Factor Receptor
Authors: Bradley Sarah V. , Holland Eric C. , Liu Grace Y. , Thomas Dafydd , Hyun Teresa S. , Ross Theodora S.
Published: March 2023

Abstract
Huntingtin interacting protein 1 (HIP1) is a multidomain oncoprotein whose expression correlates with increased epidermal growth factor receptor (EGFR) levels in certain tumors. For example, HIP1-transformed fibroblasts and HIP1-positive breast cancers have elevated EGFR protein levels. The combined association of HIP1 with huntingtin, the protein that is mutated in Huntington's disease, and the known overexpression of EGFR in glial brain tumors prompted us to explore HIP1 expression in a group of patients with different types of brain cancer. We report here that HIP1 is overexpressed with high frequency in brain cancers and that this overexpression correlates with EGFR and platelet-derived growth factor β receptor expression. Furthermore, serum samples from patients with brain cancer contained anti-HIP1 antibodies more frequently than age-matched brain cancer–free controls. Finally, we report that HIP1 physically associates with EGFR and that this association is independent of the lipid, clathrin, and actin interacting domains of HIP1. These findings suggest that HIP1 may up-regulate or maintain EGFR overexpression in primary brain tumors by directly interacting with the receptor. This novel HIP1-EGFR interaction may work with or independent of HIP1 modulation of EGFR degradation via clathrin-mediated membrane trafficking pathways. Further investigation of HIP1 function in brain cancer biology and validation of its use as a prognostic or predictive brain tumor marker are now warranted. [Cancer Res 2007;67(8):3609–15]