bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Homotypic Gap Junctional Communication Associated with Metastasis Suppression Increases with PKA Activity and Is Unaffected by PI3K Inhibition
Authors: Bodenstine Thomas M. , Vaidya Kedar S. , Ismail Aimen , Beck Benjamin H. , Cook Leah M. , Diers Anne R. , Landar Aimee , Welch Danny R.
Published: March 2024

Abstract
Loss of gap junctional intercellular communication (GJIC) between cancer cells is a common characteristic of malignant transformation. This communication is mediated by connexin proteins that make up the functional units of gap junctions. Connexins are highly regulated at the protein level and phosphorylation events play a key role in their trafficking and degradation. The metastasis suppressor breast cancer metastasis suppressor 1 (BRMS1) upregulates GJIC and decreases phosphoinositide-3-kinase (PI3K) signaling. On the basis of these observations, we set out to determine whether there was a link between PI3K and GJIC in tumorigenic and metastatic cell lines. Treatment of cells with the well-known PI3K inhibitor LY294002, and its structural analogue LY303511, which does not inhibit PI3K, increased homotypic GJIC; however, we found the effect to be independent of PI3K/AKT inhibition. We show in multiple cancer cell lines of varying metastatic capability that GJIC can be restored without enforced expression of a connexin gene. In addition, while levels of connexin 43 remained unchanged, its relocalization from the cytosol to the plasma membrane was observed. Both LY294002 and LY303511 increased the activity of protein kinase A (PKA). Moreover, PKA blockade by the small molecule inhibitor H89 decreased the LY294002/LY303511-mediated increase in GJIC. Collectively, our findings show a connection between PKA activity and GJIC mediated by PI3K-independent mechanisms of LY294002 and LY303511. Manipulation of these signaling pathways could prove useful for antimetastatic therapy. Cancer Res; 70(23); 10002–11. ©2010 AACR.
Data from Comparing Signaling Networks between Normal and Transformed Hepatocytes Using Discrete Logical Models
Authors: Saez-Rodriguez Julio , Alexopoulos Leonidas G. , Zhang MingSheng , Morris Melody K. , Lauffenburger Douglas A. , Sorger Peter K.
Published: March 2024

Abstract
Substantial effort in recent years has been devoted to constructing and analyzing large-scale gene and protein networks on the basis of “omic” data and literature mining. These interaction graphs provide valuable insight into the topologies of complex biological networks but are rarely context specific and cannot be used to predict the responses of cell signaling proteins to specific ligands or drugs. Conversely, traditional approaches to analyzing cell signaling are narrow in scope and cannot easily make use of network-level data. Here, we combine network analysis and functional experimentation by using a hybrid approach in which graphs are converted into simple mathematical models that can be trained against biochemical data. Specifically, we created Boolean logic models of immediate-early signaling in liver cells by training a literature-based prior knowledge network against biochemical data obtained from primary human hepatocytes and 4 hepatocellular carcinoma cell lines exposed to combinations of cytokines and small-molecule kinase inhibitors. Distinct families of models were recovered for each cell type, and these families clustered topologically into normal and diseased sets. Cancer Res; 71(16); 5400–11. ©2011 AACR.
Data from Peptide Vaccination after T-Cell Transfer Causes Massive Clonal Expansion, Tumor Eradication, and Manageable Cytokine Storm
Authors: Ly Long V. , Sluijter Marjolein , Versluis Mieke , Luyten Gre P.M. , van der Burg Sjoerd H. , Melief Cornelis J.M. , Jager Martine J. , van Hall Thorbald
Published: March 2024

Abstract
Adoptive T-cell transfer (ACT) is successfully applied as a cancer treatment that is based on the activation and effector functions of tumor-specific T cells. Here, we present results from a mouse model in which ACT is combined with a long peptide–based vaccine comprising gp100 T-cell epitopes. Transferred CD8+ T cells expanded up to 1,000-fold after peptide vaccination, leading to a 3-fold increase in white blood cell count and a very high frequency in the generation of antigen-specific memory T cells, the generation of which tended to correlate with effective antitumor responses. An enormous pool of effector T cells spread widely to different tissues, including the skin and the immune-privileged eye, where they mediate tumor eradication. Importantly, these striking T-cell dynamics occurred in immunocompetent mice without prior hematologic conditioning. Continued activation of the specific T-cell pool by vaccination led to strong T-cell–mediated cytokine storm and lethality due to multi-organ failure. However, this immunopathology could be prevented by controlling the rapid biodistribution of the peptide or by using a weakly agonistic peptide. Together, these results identify a peptide vaccination strategy that can potently accentuate effective ACT in non-lymphodepleted hosts. Cancer Res; 70(21); 8339–46. ©2010 AACR.
Data from Cyclin D1 and Cdk4 Mediate Development of Neurologically Destructive Oligodendroglioma
Authors: Ciznadija Daniel , Liu Yuhui , Pyonteck Stephanie M. , Holland Eric C. , Koff Andrew
Published: March 2024

Abstract
Although the molecular changes that characterize gliomas have been studied, the pathogenesis of tumor development remains unclear. p21 contributes to gliomagenesis by stabilizing cyclin D1–cdk4 kinase complexes, suggesting that cyclin D1 and cdk4 may also be required for glial tumor development. In this study, we used a mouse model to attempt to confirm this hypothesis, finding that cyclin D1 and cdk4 played active roles in not only the tumor but also the tumor microenvironment. Loss of cdk4 blocked tumor development, but loss of cyclin D1 did not prevent gliomas from developing. Instead, loss of cyclin D1 impeded progression to higher stages of malignancy. Enforcing expression of cyclin D1 was insufficient to correct the progression defect observed in cyclin D1–deficient animals. In contrast, restoration of cdk4 in the cdk4-deficient animals restored cell proliferation and tumor formation, although at lower tumor grades. Notably, the failure of tumors in the cyclin D1- and cdk4-deficient animals to progress to higher grades was correlated with a failure to fully activate microglia in the tumor microenvironment. Moreover, when platelet-derived growth factor–transformed glial cells were engrafted orthotopically into the mice, the tumors that formed progressed to high grades in wild-type mice but not cyclin D1–deficient animals. Together, our findings establish that the cyclin D1–cdk4 axis is not only critical in glial tumor cells but also in stromal-derived cells in the surrounding tumor microenvironment that are vital to sustain tumor outgrowth. Cancer Res; 71(19); 6174–83. ©2011 AACR.
Data from Paradoxical Relationship between Chromosomal Instability and Survival Outcome in Cancer
Authors: Birkbak Nicolai J. , Eklund Aron C. , Li Qiyuan , McClelland Sarah E. , Endesfelder David , Tan Patrick , Tan Iain B. , Richardson Andrea L. , Szallasi Zoltan , Swanton Charles
Published: March 2024

Abstract
Chromosomal instability (CIN) is associated with poor prognosis in human cancer. However, in certain animal tumor models elevated CIN negatively impacts upon organism fitness, and is poorly tolerated by cancer cells. To better understand this seemingly contradictory relationship between CIN and cancer cell biological fitness and its relationship with clinical outcome, we applied the CIN70 expression signature, which correlates with DNA-based measures of structural chromosomal complexity and numerical CIN in vivo, to gene expression profiles of 2,125 breast tumors from 13 published cohorts. Tumors with extreme CIN, defined as the highest quartile CIN70 score, were predominantly of the estrogen receptor negative (ER−), basal-like phenotype and displayed the highest chromosomal structural complexity and chromosomal numerical instability. We found that the extreme CIN/ER− tumors were associated with improved prognosis relative to tumors with intermediate CIN70 scores in the third quartile. We also observed this paradoxical relationship between CIN and prognosis in ovarian, gastric, and non–small cell lung cancer, with poorest outcome in tumors with intermediate, rather than extreme, CIN70 scores. These results suggest a nonmonotonic relationship between gene signature expression and HR for survival outcome, which may explain the difficulties encountered in the identification of prognostic expression signatures in ER− breast cancer. Furthermore, the data are consistent with the intolerance of excessive CIN in carcinomas and provide a plausible strategy to define distinct prognostic patient cohorts with ER− breast cancer. Inclusion of a surrogate measurement of CIN may improve cancer risk stratification and future therapeutic approaches. Cancer Res; 71(10); 3447–52. ©2011 AACR.
Data from A Mutation Threshold Distinguishes the Antitumorigenic Effects of the Mitochondrial Gene MTND1, an Oncojanus Function
Authors: Gasparre Giuseppe , Kurelac Ivana , Capristo Mariantonietta , Iommarini Luisa , Ghelli Anna , Ceccarelli Claudio , Nicoletti Giordano , Nanni Patrizia , De Giovanni Carla , Scotlandi Katia , Betts Christine M. , Carelli Valerio , Lollini Pier Luigi , Romeo Giovanni , Rugolo Michela , Porcelli Anna Maria
Published: March 2024

Abstract
The oncogenic versus suppressor roles of mitochondrial genes have long been debated. Peculiar features of mitochondrial genetics such as hetero/homoplasmy and mutation threshold are seldom taken into account in this debate. Mitochondrial DNA (mtDNA) mutations generally have been claimed to be protumorigenic, but they are also hallmarks of mostly benign oncocytic tumors wherein they help reduce adaptation to hypoxia by destabilizing hypoxia-inducible factor-1α (HIF1α). To determine the influence of a disassembling mtDNA mutation and its hetero/homoplasmy on tumorigenic and metastatic potential, we injected mice with tumor cells harboring different loads of the gene MTND1 m.3571insC. Cell cultures obtained from tumor xenografts were then analyzed to correlate energetic competence, apoptosis, α-ketoglutarate (α-KG)/succinate (SA) ratio, and HIF1α stabilization with the mutation load. A threshold level for the antitumorigenic effect of MTND1 m.3571insC mutation was defined, above which tumor growth and invasiveness were reduced significantly. Notably, HIF1α destabilization and downregulation of HIF1α-dependent genes occurred in cells and tumors lacking complex I (CI), where there was an associated imbalance of α-KG/SA despite the presence of an actual hypoxic environment. These results strongly implicate mtDNA mutations as a cause of oncocytic transformation. Thus, the antitumorigenic and antimetastatic effects of high loads of MTND1 m.3571insC, following CI disassembly, define a novel threshold-regulated class of cancer genes. We suggest these genes be termed oncojanus genes to recognize their ability to contribute either oncogenic or suppressive functions in mitochondrial settings during tumorigenesis. Cancer Res; 71(19); 6220–9. ©2011 AACR.
Data from Enhancement of TGF-β Signaling Responses by the E3 Ubiquitin Ligase Arkadia Provides Tumor Suppression in Colorectal Cancer
Authors: Sharma Vikas , Antonacopoulou Anna G. , Tanaka Shinya , Panoutsopoulos Alexios A. , Bravou Vasiliki , Kalofonos Haralabos P. , Episkopou Vasso
Published: March 2024

Abstract
TGF-β signaling provides tumor protection against colorectal cancer (CRC). Mechanisms that support its tumor-suppressive properties remain unclear. The ubiquitin ligase Arkadia/RNF111 enhances TGF-β signaling responses by targeting repressors of the pathway for degradation. The corepressors SnoN/Ski, critical substrates of Arkadia, complex with the activated TGF-β signaling effectors Smad2/3 (pSmad2/3) on the promoters of target genes and block their transcription. Arkadia degrades this complex including pSmad2/3 and unblocks the promoter. Here, we report that Arkadia is expressed highly in the mouse colonic epithelium. Heterozygous Akd+/− mice are normal but express less Arkadia. This leads to reduced expression of several TGF-β target genes, suggesting that normal levels of Arkadia are required for efficient signaling responses. Critically, Akd+/− mice exhibit increased susceptibility to azoxymethane/dextran sodium sulfate carcinogen–induced CRC, as they develop four-fold more tumors than wild-type mice. Akd+/− tumors also exhibit a more aggressive pathology, higher proliferation index, and reduced cytostasis. Therefore, Arkadia functions as a tumor suppressor whose peak expression is required to suppress CRC development and progression. The accumulation of nuclear SnoN and pSmad2, along with the downregulation of TGF-β target genes observed in Akd+/− colon and tumors, suggest that tumor-suppressing properties of Arkadia are mediated by its ability to derepress TGF-β signaling. Consistent with this likelihood, we identified mutations in primary colorectal tumors from human patients that reduce Arkadia function and are associated with the accumulation of nuclear SNON. Collectively, our findings reveal that Arkadia enhances TGF-β signaling responses and supports its tumor-suppressing properties in CRC. Cancer Res; 71(20); 6438–49. ©2011 AACR.
Data from IFN-γ Inhibits Gastric Carcinogenesis by Inducing Epithelial Cell Autophagy and T-Cell Apoptosis
Authors: Tu Shui Ping , Quante Michael , Bhagat Govind , Takaishi Shigeo , Cui Guanglin , Yang Xiang Dong , Muthuplani Sureshkumar , Shibata Wataru , Fox James G. , Pritchard D. Mark , Wang Timothy C.
Published: March 2024

Abstract
IFN-γ mediates responses to bacterial infection and autoimmune disease, but it is also an important tumor suppressor. It is upregulated in the gastric mucosa by chronic Helicobacter infection; however, whether it plays a positive or negative role in inflammation-associated gastric carcinogenesis is unexplored. To study this question, we generated an H+/K+-ATPase-IFN-γ transgenic mouse that overexpresses murine IFN-γ in the stomach mucosa. In contrast to the expected proinflammatory role during infection, we found that IFN-γ overexpression failed to induce gastritis and instead inhibited gastric carcinogenesis induced by interleukin-1beta (IL-1β) and/or Helicobacter infection. Helper T cell (Th) 1 and Th17 immune responses were inhibited by IFN-γ through Fas induction and apoptosis in CD4 T cells. IFN-γ also induced autophagy in gastric epithelial cells through increased expression of Beclin-1. Finally, in the gastric epithelium, IFN-γ also inhibited IL-1β- and Helicobacter-induced epithelial apoptosis, proliferation, and Dckl1+ cell expansion. Taken together, our results suggest that IFN-γ coordinately inhibits bacterial infection and carcinogenesis in the gastric mucosa by suppressing putative gastric progenitor cell expansion and reducing epithelial cell apoptosis via induction of an autophagic program. Cancer Res; 71(12); 4247–59. ©2011 AACR.
Data from HB-EGF and PDGF Mediate Reciprocal Interactions of Carcinoma Cells with Cancer-Associated Fibroblasts to Support Progression of Uterine Cervical Cancers
Authors: Murata Takuya , Mizushima Hiroto , Chinen Ichino , Moribe Hiroki , Yagi Shigeo , Hoffman Robert M. , Kimura Tadashi , Yoshino Kiyoshi , Ueda Yutaka , Enomoto Takayuki , Mekada Eisuke
Published: March 2024

Abstract
Tumor stroma drives the growth and progression of cancers. A heparin-binding epidermal growth factor–like growth factor, HB-EGF, is an EGF receptor ligand that stimulates cell growth in an autocrine or paracrine fashion. While elevated expression of HB-EGF in cancer cells and its contribution to tumor progression are well documented, the effects of HB-EGF expression in the tumor stroma have not been clarified. Here, we show that HB-EGF is expressed in stromal fibroblasts where it promotes cancer cell proliferation. In uterine cervical cancers, HB-EGF was detected immunohistochemically in the stroma proximal to the cancer epithelium. Proliferation of cervical cancer cells in vitro was enhanced by coculture with fibroblasts isolated from tumor tissues of patients with cervical cancer. Inhibition of HB-EGF function or treatment with platelet–derived growth factor (PDGF) inhibitors abrogated cancer cell growth enhanced by cervical cancer–associated fibroblast (CCF) coculture. Furthermore, tumor formation in a mouse xenograft model was enhanced by cotransplantation of CCF or mouse embryonic fibroblasts, but not with embryonic fibroblasts from HB-EGF–deficient mice. Conversely, conditioned medium from cancer cells induced HB-EGF expression in CCF. Mechanistic investigations established that PDGF was the primary factor responsible. Together, our findings indicate that HB-EGF and PDGF reciprocally mediate the interaction of cancer cells with cancer-associated fibroblasts, promoting cancer cell proliferation in a paracrine manner that has implications for novel combinatorial cancer therapies. Cancer Res; 71(21); 6633–42. ©2011 AACR.
Data from Interaction between FGFR-2, STAT5, and Progesterone Receptors in Breast Cancer
Authors: Cerliani Juan P. , Guillardoy Tomás , Giulianelli Sebastián , Vaque José P. , Gutkind J. Silvio , Vanzulli Silvia I. , Martins Rubén , Zeitlin Eduardo , Lamb Caroline A. , Lanari Claudia
Published: March 2024

Abstract
Fibroblast growth factor (FGF) receptor 2 (FGFR-2) polymorphisms have been associated with an increase in estrogen receptor and progesterone receptor (PR)-positive breast cancer risk; however, a clear mechanistic association between FGFR-2 and steroid hormone receptors remains elusive. In previous works, we have shown a cross talk between FGF2 and progestins in mouse mammary carcinomas. To investigate the mechanisms underlying these interactions and to validate our findings in a human setting, we have used T47D human breast cancer cells and human cancer tissue samples. We showed that medroxyprogesterone acetate (MPA) and FGF2 induced cell proliferation and activation of ERK, AKT, and STAT5 in T47D and in murine C4-HI cells. Nuclear interaction between PR, FGFR-2, and STAT5 after MPA and FGF2 treatment was also showed by confocal microscopy and immunoprecipitation. This effect was associated with increased transcription of PRE and/or GAS reporter genes, and of PR/STAT5-regulated genes and proteins. Two antiprogestins and the FGFR inhibitor PD173074, specifically blocked the effects induced by FGF2 or MPA respectively. The presence of PR/FGFR-2/STAT5 complexes bound to the PRE probe was corroborated by using NoShift transcription and chromatin immunoprecipitation of the MYC promoter. Additionally, we showed that T47D cells stably transfected with constitutively active FGFR-2 gave rise to invasive carcinomas when transplanted into NOD/SCID mice. Nuclear colocalization between PR and FGFR-2/STAT5 was also observed in human breast cancer tissues. This study represents the first demonstration of a nuclear interaction between FGFR-2 and STAT5, as PR coactivators at the DNA progesterone responsive elements, suggesting that FGFRs are valid therapeutic targets for human breast cancer treatment. Cancer Res; 71(10); 3720–31. ©2011 AACR.
Data from p53-Dependent Regulation of Mitochondrial Energy Production by the RelA Subunit of NF-κB
Authors: Johnson Renée F. , Witzel Ini-Isabée , Perkins Neil D.
Published: March 2024

Abstract
Aberrant activity of the nuclear factor kappaB (NF-κB) transcription factor family, which regulates cellular responses to stress and infection, is associated with many human cancers. In this study, we define a function of NF-κB in regulation of cellular respiration that is dependent upon the tumor suppressor p53. Translocation of the NF-κB family member RelA to mitochondria was inhibited by p53 by blocking an essential interaction with the HSP Mortalin. However, in the absence of p53, RelA was transported into the mitochondria and recruited to the mitochondrial genome where it repressed mitochondrial gene expression, oxygen consumption, and cellular ATP levels. We found mitochondrial RelA function to be dependent on its conserved C-terminal transactivation domain and independent of its sequence-specific DNA-binding ability, suggesting that its function in this setting was mediated by direct interaction with mitochondrial transcription factors. Taken together, our findings uncover a new mechanism through which RelA can regulate mitochondrial function, with important implications for how NF-κB activity and loss of p53 can contribute to changes in tumor cell metabolism and energy production. Cancer Res; 71(16); 5588–97. ©2011 AACR.
Data from Integrity of SOS1/EPS8/ABI1 Tri-Complex Determines Ovarian Cancer Metastasis
Authors: Chen Huijun , Wu Xufeng , Pan Zhixing K. , Huang Shuang
Published: March 2024

Abstract
Ovarian cancer is mainly confined in peritoneal cavity and its metastasis is often associated with the formation of malignant ascites. As lysophosphatidic acid (LPA) is present at high levels in ascites of ovarian cancer patients and potently stimulates cell migration, we reason that LPA-stimulated cell migration may play an important role in ovarian cancer metastasis. Here, we show that only ovarian cancer cell lines with LPA migratory response undergo peritoneal metastatic colonization. LPA-stimulated cell migration is required for metastatic colonization because knockdown of LPA receptor subtype 1 (LPAR1) abolishes this event. However, the difference in metastatic potentials is not caused by the absence of LPAR1 because both metastatic and nonmetastatic lines express similar levels of LPAR1. Instead, we find that LPA can activate Rac only in metastatic cells and that metastatic colonization of ovarian cancer cells necessitates Rac activity. These results thus suggest that LPA-induced Rac activation is a prerequisite for ovarian cancer metastasis. In metastatic cells, Rac activation is facilitated by SOS1/EPS8/ABI1 tri-complex and the integrity of this tri-complex is essential for LPA-stimulated cell migration and metastatic colonization. We show that at least 1 member of SOS1/EPS8/ABI1 tri-complex is absent in nonmetastatic ovarian cancer cells and reexpressing the missing one conferred them with metastatic capability. Importantly, coexpression of SOS1, EPS8, and ABI1, but not of any individual member of SOS1/EPS8/ABI1 tri-complex, correlates with advanced stages and shorter survival of ovarian cancer patients. Our study implicates that the integrity of SOS1/EPS8/ABI1 tri-complex is a determinant of ovarian cancer metastasis. Cancer Res; 70(23); 9979–90. ©2010 AACR.
Data from miRNA-7 Attenuation in Schwannoma Tumors Stimulates Growth by Upregulating Three Oncogenic Signaling Pathways
Authors: Saydam Okay , Senol Ozlem , Würdinger Thomas , Mizrak Arda , Ozdener Gokhan Baris , Stemmer-Rachamimov Anat O. , Yi Ming , Stephens Robert M. , Krichevsky Anna M. , Saydam Nurten , Brenner Gary J. , Breakefield Xandra O.
Published: March 2024

Abstract
Micro RNAs (miRNA) negatively regulate protein-coding genes at the posttranscriptional level and are critical in tumorigenesis. Schwannomas develop from proliferation of dedifferentiated Schwann cells, which normally wrap nerve fibers to help support and insulate nerves. In this study, we carried out high-throughput miRNA expression profiling of human vestibular schwannomas by using an array representing 407 known miRNAs to explore the role of miRNAs in tumor growth. Twelve miRNAs were found to be significantly deregulated in tumor samples as compared with control nerve tissue, defining a schwannoma-typical signature. Among these miRNAs, we focused on miR-7, which was one of the most downregulated in these tumors and has several known oncogene targets, including mRNAs for epidermal growth factor receptor (EGFR) and p21-activated kinase 1 (Pak1). We found that overexpression of miR-7 inhibited schwannoma cell growth both in culture and in xenograft tumor models in vivo, which correlated with downregulation of these signaling pathways. Furthermore, we identified a novel direct target of miR-7, the mRNA for associated cdc42 kinase 1 (Ack1), with the expression levels of miR-7 and Ack1 being inversely correlated in human schwannoma samples. These results represent the first miRNA profiling of schwannomas and the first report of a tumor suppressor function for miR-7 in these tumors that is mediated by targeting the EGFR, Pak1, and Ack1 oncogenes. Our findings suggest miR-7 as a potential therapeutic molecule for schwannoma treatment, and they prompt clinical evaluation of drugs that can inhibit the EGFR, Pak1, and Ack1 signaling pathways to treat this tumor type. Cancer Res; 71(3); 852–61. ©2010 AACR.
Data from LIN28B Promotes Colon Cancer Progression and Metastasis
Authors: King Catrina E. , Cuatrecasas Miriam , Castells Antoni , Sepulveda Antonia R. , Lee Ju-Seog , Rustgi Anil K.
Published: March 2024

Abstract
LIN28B is a homologue of LIN28 that induces pluripotency when expressed in conjunction with OCT4, SOX2, and KLF4 in somatic fibroblasts. LIN28B represses biogenesis of let-7 microRNAs and is implicated in both development and tumorigenesis. Recently, we have determined that LIN28B overexpression occurs in colon tumors. We conducted a comprehensive analysis of LIN28B protein expression in human colon adenocarcinomas. We found that LIN28B overexpression correlates with reduced patient survival and increased probability of tumor recurrence. To elucidate tumorigenic functions of LIN28B, we constitutively expressed LIN28B in colon cancer cells and evaluated tumor formation in vivo. Tumors with constitutive LIN28B expression exhibit increased expression of colonic stem cell markers LGR5 and PROM1, mucinous differentiation, and metastasis. Together, our findings point to a function for LIN28B in promoting colon tumor pathogenesis, especially metastasis. Cancer Res; 71(12); 4260–8. ©2011 AACR.
Data from MET-Independent Lung Cancer Cells Evading EGFR Kinase Inhibitors Are Therapeutically Susceptible to BH3 Mimetic Agents
Authors: Fan Weiwen , Tang Zhe , Yin Lihong , Morrison Bei , Hafez-Khayyata Said , Fu Pingfu , Huang Honglian , Bagai Rakesh , Jiang Shan , Kresak Adam , Howell Scott , Vasanji Amit , Flask Chris A. , Halmos Balazs , Koon Henry , Ma Patrick C.
Published: March 2024

Abstract
Targeted therapies for cancer are inherently limited by the inevitable recurrence of resistant disease after initial responses. To define early molecular changes within residual tumor cells that persist after treatment, we analyzed drug-sensitive lung adenocarcinoma cell lines exposed to reversible or irreversible epidermal growth factor receptor (EGFR) inhibitors, alone or in combination with MET-kinase inhibitors, to characterize the adaptive response that engenders drug resistance. Tumor cells displaying early resistance exhibited dependence on MET-independent activation of BCL-2/BCL-XL survival signaling. Further, such cells displayed a quiescence-like state associated with greatly retarded cell proliferation and cytoskeletal functions that were readily reversed after withdrawal of targeted inhibitors. Findings were validated in a xenograft model, showing BCL-2 induction and p-STAT3[Y705] activation within the residual tumor cells surviving the initial antitumor response to targeted therapies. Disrupting the mitochondrial BCL-2/BCL-XL antiapoptotic machinery in early survivor cells using BCL-2 Homology Domain 3 (BH3) mimetic agents such as ABT-737, or by dual RNAi-mediated knockdown of BCL-2/BCL-XL, was sufficient to eradicate the early-resistant lung-tumor-cells evading targeted inhibitors. Similarly, in a xenograft model the preemptive cotreatment of lung tumor cells with an EGFR inhibitor and a BH3 mimetic eradicated early TKI-resistant evaders and ultimately achieved a more durable response with prolonged remission. Our findings prompt prospective clinical investigations using BH3-mimetics combined with targeted receptor kinase inhibitors to optimize and improve clinical outcomes in lung-cancer treatment. Cancer Res; 71(13); 4494–505. ©2011 AACR.
Data from Histone Methyltransferase EZH2 Induces Akt-Dependent Genomic Instability and BRCA1 Inhibition in Breast Cancer
Authors: Gonzalez Maria E. , DuPrie Matthew L. , Krueger Heather , Merajver Sofia D. , Ventura Alejandra C. , Toy Kathy A. , Kleer Celina G.
Published: March 2024

Abstract
Increased levels of EZH2, a critical regulator of cellular memory, signal the presence of metastasis and poor outcome in breast cancer patients. High levels of EZH2 are associated with nuclear pleomorphism, lack of estrogen receptor expression, and decreased nuclear levels of BRCA1 tumor suppressor protein in invasive breast carcinomas. The mechanism by which EZH2 overexpression promotes the growth of poorly differentiated invasive carcinomas remains to be defined. Here, we show that EZH2 controls the intracellular localization of BRCA1 protein. Conditional doxycycline-induced upregulation of EZH2 in benign mammary epithelial cells results in nuclear export of BRCA1 protein, aberrant mitoses with extra centrosomes, and genomic instability. EZH2 inhibition in CAL51 breast cancer cells induces BRCA1 nuclear localization and rescues defects in ploidy and mitosis. Mechanistically, EZH2 overexpression is sufficient for activation of the phosphoinositide 3-kinase/Akt (PI3K/Akt) pathway specifically through activation of Akt isoform 1. EZH2-induced BRCA1 nuclear export, aneuploidy, and mitotic defects were prevented by treatment with the PI3K inhibitors LY294002 or wortmannin. Targeted inhibition of Akt-1, Akt-2, and Akt-3 isoforms revealed that the EZH2-induced phenotype requires specific activation of Akt-1. The relevance of our studies to human breast cancer is highlighted by the finding that high EZH2 protein levels are associated with upregulated expression of phospho-Akt-1 (Ser473) and decreased nuclear expression of phospho-BRCA1 (Ser1423) in 39% of invasive breast carcinomas. These results enable us to pinpoint one mechanism by which EZH2 regulates BRCA1 expression and genomic stability mediated by the PI3K/Akt-1 pathway. Cancer Res; 71(6); 2360–70. ©2011 AACR.
Data from c-Myc Regulates RNA Splicing of the A-Raf Kinase and Its Activation of the ERK Pathway
Authors: Rauch Jens , Moran-Jones Kim , Albrecht Valerie , Schwarzl Thomas , Hunter Keith , Gires Olivier , Kolch Walter
Published: March 2024

Abstract
A-Raf kinase can inhibit apoptosis by binding to the proapoptotic mammalian sterile 20-like kinase (MST2). This function relies on expression of hnRNP H, which ensures the correct splicing of a-raf mRNA needed to produce full-length A-Raf protein. Here, we showed that expression of hnRNP H and production of full-length A-Raf is positively controlled by c-Myc. Low c-Myc reduces hnRNP H expression and switches a-raf splicing to produce A-Rafshort, a truncated protein. Importantly, A-Rafshort fails to regulate MST2 but retains the Ras-binding domain such that it functions as a dominant negative mutant suppressing Ras activation and transformation. Human colon and head and neck cancers exhibit high hnRNP H and high c-Myc levels resulting in enhanced A-Raf expression and reduced expression of A-Rafshort. Conversely, in normal cells and tissues in which c-Myc and hnRNP H are low, A-Rafshort suppresses extracellular signal regulated kinase activation such that it may act as a safeguard against oncogenic transformation. Our findings offered a new paradigm to understand how c-Myc coordinates diverse cell functions by directly affecting alternate splicing of key signaling components. Cancer Res; 71(13); 4664–74. ©2011 AACR.
Data from Correlation of Somatic Mutation and Expression Identifies Genes Important in Human Glioblastoma Progression and Survival
Authors: Masica David L. , Karchin Rachel
Published: March 2024

Abstract
Cooperative dysregulation of gene sequence and expression may contribute to cancer formation and progression. The Cancer Genome Atlas (TCGA) Network recently catalogued gene sequence and expression data for a collection of glioblastoma multiforme (GBM) tumors. We developed an automated, model-free method to rapidly and exhaustively examine the correlation among somatic mutation and gene expression and interrogated 149 GBM tumor samples from the TCGA. The method identified 41 genes whose mutation status is highly correlated with drastic changes in the expression (z-score ± 2.0), across tumor samples, of other genes. Some of the 41 genes have been previously implicated in GBM pathogenesis (e.g., NF1, TP53, RB1, and IDH1) and others, while implicated in cancer, had not previously been highlighted in studies using TCGA data (e.g., SYNE1, KLF6, FGFR4, and EPHB4). The method also predicted that known oncogenes and tumor suppressors participate in GBM via drastic over- and underexpression, respectively. In addition, the method identified a known synthetic lethal interaction between TP53 and PLK1, other potential synthetic lethal interactions with TP53, and correlations between IDH1 mutation status and the overexpression of known GBM survival genes. Cancer Res; 71(13); 4550–61. ©2011 AACR.
Data from Human NK Cells Are Alerted to Induction of p53 in Cancer Cells by Upregulation of the NKG2D Ligands ULBP1 and ULBP2
Authors: Textor Sonja , Fiegler Nathalie , Arnold Annette , Porgador Angel , Hofmann Thomas G. , Cerwenka Adelheid
Published: March 2024

Abstract
Natural killer (NK) cells are immune cells sensing and eliminating foreign, stressed, transformed, and senescent cells through specialized surface receptors, such as NKG2D, that interacts with several virus- or stress-inducible ligands, including ULBP1 and -2, which are expressed on target cell surfaces. For example, induction of DNA damage or cellular senescence pathways in tumor cells led to upregulation of NKG2D ligands that activate NK cells. Although, both pathways activate p53, the relationship of p53 activation to upregulation of NKG2D ligands has not been addressed. In this study, we report that induction of wild-type p53, but not mutant p53, strongly upregulated mRNA and cell surface expression of ULBP1 and -2, whereas expression of other NK cell ligands was not affected. We defined intronic p53-responsive elements in these two novel p53 target genes. Coculture of wild-type p53-induced human tumor cells with primary human NK cells enhanced NKG2D-dependent degranulation and IFN-γ production by NK cells. Accordingly, treatment of certain wild-type p53-expressing tumor cell lines with the p53-reactivating small molecular compound RITA resulted in upregulation of ULBP2 mRNA and cell surface protein expression. Taken together, our findings define the involvement of p53 in the regulation of specific NKG2D ligands that enhance NK cell–mediated target recognition. One implication of our work is that activating p53 after adoptive transfer of NK cells might constitute an effective combinatorial strategy of NK cell–based immunochemotherapy in cancers in which wild-type p53 function is preserved. Cancer Res; 71(18); 5998–6009. ©2011 AACR.
Data from Notch Signaling Activated by Replication Stress–Induced Expression of Midkine Drives Epithelial–Mesenchymal Transition and Chemoresistance in Pancreatic Cancer
Authors: Güngör Cenap , Zander Hilke , Effenberger Katharina E. , Vashist Yogesh K. , Kalinina Tatyana , Izbicki Jakob R. , Yekebas Emre , Bockhorn Maximilian
Published: March 2024

Abstract
The incidence of pancreatic ductal adenocarcinoma (PDAC) nearly equals its mortality rate, partly because most PDACs are intrinsically chemoresistant and thus largely untreatable. It was found recently that chemoresistant PDAC cells overexpress the Notch-2 receptor and have undergone epithelial–mesenchymal transition (EMT). In this study, we show that these two phenotypes are interrelated by expression of Midkine (MK), a heparin-binding growth factor that is widely overexpressed in chemoresistant PDAC. Gemcitabine, the front-line chemotherapy used in PDAC treatment, induced MK expression in a dose-dependent manner, and its RNAi-mediated depletion was associated with sensitization to gemcitabine treatment. We identified an interaction between the Notch-2 receptor and MK in PDAC cells. MK–Notch-2 interaction activated Notch signaling, induced EMT, upregulated NF-κB, and increased chemoresistance. Taken together, our findings define an important pathway of chemoresistance in PDAC and suggest novel strategies for its clinical attack. Cancer Res; 71(14); 5009–19. ©2011 AACR.
Data from Aberrant Activation of Fatty Acid Synthesis Suppresses Primary Cilium Formation and Distorts Tissue Development
Authors: Willemarck Nicolas , Rysman Evelien , Brusselmans Koen , Van Imschoot Griet , Vanderhoydonc Frank , Moerloose Katrien , Lerut Evelyne , Verhoeven Guido , van Roy Frans , Vleminckx Kris , Swinnen Johannes V.
Published: March 2024

Abstract
Aberrant activation of fatty acid synthesis is a key feature of many advanced human cancers. Unlike in classical lipogenic tissues, this process has been implicated in membrane production required for rapid cell proliferation. Here, to gain further insight into the consequences of tumor-associated fatty acid synthesis, we have mimicked the lipogenic phenotype of cancer cells in Xenopus embryos by microinjection of RNA encoding the lipogenic transcription factor sterol regulatory element binding protein 1c (SREBP1c). Dramatic morphologic changes were observed that could be linked to alterations in Wnt and Hedgehog signaling, and ultimately to a distortion of the primary cilium. This is a sophisticated microtubular sensory organelle that is expressed on the surface of nearly every cell type and that is lost in many cancers. SREBP1c-induced loss of the primary cilium could be confirmed in mammalian Madin-Darby canine kidney (MDCK) cells and was mediated by changes in the supply of fatty acids. Conversely, inhibition of fatty acid synthesis in highly lipogenic human prostate cancer cells restored the formation of the primary cilium. Lipid-induced ciliary loss was associated with mislocalization of apical proteins, distortion of cell polarization, and aberrant epithelial tissue development as revealed in three-dimensional cultures of MDCK cells and in the developing mouse prostate. These data imply that tumor-associated lipogenesis, in addition to rendering cells more autonomous in terms of lipid supply, disturbs cilium formation and contributes to impaired environmental sensing, aberrant signaling, and distortion of polarized tissue architecture, which are all hallmarks of cancer. Cancer Res; 70(22); 9453–62. ©2010 AACR.
Data from Overexpression of MBD2 in Glioblastoma Maintains Epigenetic Silencing and Inhibits the Antiangiogenic Function of the Tumor Suppressor Gene BAI1
Authors: Zhu Dan , Hunter Stephen B. , Vertino Paula M. , Van Meir Erwin G.
Published: March 2024

Abstract
Brain angiogenesis inhibitor 1 (BAI1) is a putative G protein–coupled receptor with potent antiangiogenic and antitumorigenic properties that is mutated in certain cancers. BAI1 is expressed in normal human brain, but it is frequently silenced in glioblastoma multiforme. In this study, we show that this silencing event is regulated by overexpression of methyl-CpG–binding domain protein 2 (MBD2), a key mediator of epigenetic gene regulation, which binds to the hypermethylated BAI1 gene promoter. In glioma cells, treatment with the DNA demethylating agent 5-aza-2′-deoxycytidine (5-Aza-dC) was sufficient to reactivate BAI1 expression. Chromatin immunoprecipitation showed that MBD2 was enriched at the promoter of silenced BAI1 in glioma cells and that MBD2 binding was released by 5-Aza-dC treatment. RNA interference–mediated knockdown of MBD2 expression led to reactivation of BAI1 gene expression and restoration of BAI1 functional activity, as indicated by increased antiangiogenic activity in vitro and in vivo. Taken together, our results suggest that MBD2 overexpression during gliomagenesis may drive tumor growth by suppressing the antiangiogenic activity of a key tumor suppressor. These findings have therapeutic implications because inhibiting MBD2 could offer a strategy to reactivate BAI1 and suppress glioma pathobiology. Cancer Res; 71(17); 5859–70. ©2011 AACR.
Data from Dendritic Cell Internalization of α-Galactosylceramide from CD8 T Cells Induces Potent Antitumor CD8 T-cell Responses
Authors: Choi Dong Hoon , Kim Kwang Soon , Yang Se Hwan , Chung Doo Hyun , Song Boyeong , Sprent Jonathan , Cho Jae Ho , Sung Young Chul
Published: March 2024

Abstract
Dendritic cells (DC) present α-galactosylceramide (αGalCer) to invariant T-cell receptor–expressing natural killer T cells (iNKT) activating these cells to secrete a variety of cytokines, which in turn results in DC maturation and activation of other cell types, including NK cells, B cells, and conventional T cells. In this study, we showed that αGalCer-pulsing of antigen-activated CD8 T cells before adoptive transfer to tumor-bearing mice caused a marked increase in donor T-cell proliferation, precursor frequency, and cytotoxic lymphocyte activity. This effect was interleukin (IL)-2 dependent and involved both natural killer T cells (NKT) and DCs, as mice lacking IL-2, NKTs, and DCs lacked any enhanced response to adoptively transferred αGalCer-loaded CD8 T cells. iNKT activation was mediated by transfer of αGalCer from the cell membrane of the donor CD8 T cells onto the αGalCer receptor CD1d which is present on host DCs. αGalCer transfer was increased by prior activation of the donor CD8 T cells and required AP-2–mediated endocytosis by host DCs. In addition, host iNKT cell activation led to strong IL-2 synthesis, thereby increasing expansion and differentiation of donor CD8 T cells. Transfer of these cells led to improved therapeutic efficacy against established solid tumors in mice. Thus, our findings illustrate how αGalCer loading of CD8 T cells after antigen activation in vitro may leverage the therapeutic potential of adoptive T-cell therapies. Cancer Res; 71(24); 7442–51. ©2011 AACR.
Data from Identification of Anaplastic Lymphoma Kinase as a Potential Therapeutic Target in Ovarian Cancer
Authors: Ren Hong , Tan Zhi-Ping , Zhu Xin , Crosby Katherine , Haack Herbert , Ren Jian-Min , Beausoleil Sean , Moritz Albrecht , Innocenti Gregory , Rush John , Zhang Yi , Zhou Xin-Min , Gu Ting-Lei , Yang Yi-Feng , Comb Michael J.
Published: March 2024

Abstract
Ovarian cancer is the leading cause of death from gynecologic cancer. Improvement in the clinical outcome of patients is likely to be achieved by the identification of molecular events that underlie the oncogenesis of ovarian cancer. Here we show that the anaplastic lymphoma kinase (ALK) is aberrantly activated in ovarian cancer. Using an unbiased and global phosphoproteomic approach, we profiled 69 Chinese primary ovarian tumor tissues and found ALK to be aberrantly expressed and phosphorylated in 4 tumors. Genetic characterization of these ALK-positive tumors indicated that full-length ALK expression in two serous carcinoma patients is consistent with ALK gene copy number gain, whereas a stromal sarcoma patient carries a novel transmembrane ALK fusion gene: FN1-ALK. Biochemical and functional analysis showed that both full-length ALK and FN1-ALK are oncogenic, and tumors expressing ALK or FN1-ALK are sensitive to ALK kinase inhibitors. Furthermore, immunohistochemical analysis of ovarian tumor tissue microarray detected aberrant ALK expression in 2% to 4% serous carcinoma patients. Our findings provide new insights into the pathogenesis of ovarian cancer and identify ALK as a potential therapeutic target in a subset of serous ovarian carcinoma and stromal sarcoma patients. Cancer Res; 72(13); 3312–23. ©2012 AACR.
Data from MIF Produced by Bone Marrow–Derived Macrophages Contributes to Teratoma Progression after Embryonic Stem Cell Transplantation
Authors: Wang Xi , Chen Tianxiang , Leng Lin , Fan Jianqing , Cao Kai , Duan Zhaoxia , Zhang Xijing , Shao Changshun , Wu Mingmei , Tadmori Iman , Li Tianyi , Liang Li , Sun Dongming , Zheng Shusen , Meinhardt Andreas , Young Wise , Bucala Richard , Ren Yi
Published: March 2024

Abstract
Although stem cell therapy holds promise as a potential treatment in a number of diseases, the tumorigenicity of embryonic stem cells (ESC) and induced pluripotent stem cells remains a major obstacle. In vitro predifferentiation of ESCs can help prevent the risk of teratoma formation, yet proliferating neural progenitors can generate tumors, especially in the presence of immunosuppressive therapy. In this study, we investigated the effects of the microenvironment on stem cell growth and teratoma development using undifferentiated ESCs. Syngeneic ESC transplantation triggered an inflammatory response that involved the recruitment of bone marrow (BM)–derived macrophages. These macrophages differentiated into an M2 or angiogenic phenotype that expressed multiple angiogenic growth factors and proteinases, such as macrophage migration inhibitory factor (MIF), VEGF, and matrix metalloproteinase 9, creating a microenvironment that supported the initiation of teratoma development. Genetic deletion of MIF from the host but not from ESCs specifically reduced angiogenesis and teratoma growth, and MIF inhibition effectively reduced teratoma development after ESC transplantation. Together, our findings show that syngeneic ESC transplantation provokes an inflammatory response that involves the rapid recruitment and activation of BM-derived macrophages, which may be a crucial driving force in the initiation and progression of teratomas. Cancer Res; 72(11); 2867–78. ©2012 AACR.
Data from Systematic Analysis of MicroRNAs Targeting the Androgen Receptor in Prostate Cancer Cells
Authors: Östling Päivi , Leivonen Suvi-Katri , Aakula Anna , Kohonen Pekka , Mäkelä Rami , Hagman Zandra , Edsjö Anders , Kangaspeska Sara , Edgren Henrik , Nicorici Daniel , Bjartell Anders , Ceder Yvonne , Perälä Merja , Kallioniemi Olli
Published: March 2024

Abstract
Androgen receptor (AR) is expressed in all stages of prostate cancer progression, including in castration-resistant tumors. Eliminating AR function continues to represent a focus of therapeutic investigation, but AR regulatory mechanisms remain poorly understood. To systematically characterize mechanisms involving microRNAs (miRNAs), we conducted a gain-of function screen of 1129 miRNA molecules in a panel of human prostate cancer cell lines and quantified changes in AR protein content using protein lysate microarrays. In this way, we defined 71 unique miRNAs that influenced the level of AR in human prostate cancer cells. RNA sequencing data revealed that the 3′UTR of AR (and other genes) is much longer than currently used in miRNA target prediction programs. Our own analyses predicted that most of the miRNA regulation of AR would target an extended 6 kb 3′UTR. 3′UTR-binding assays validated 13 miRNAs that are able to regulate this long AR 3′UTR (miR-135b, miR-185, miR-297, miR-299-3p, miR-34a, miR-34c, miR-371–3p, miR-421, miR-449a, miR-449b, miR-634, miR-654–5p, and miR-9). Fifteen AR downregulating miRNAs decreased androgen-induced proliferation of prostate cancer cells. In particular, analysis of clinical prostate cancers confirmed a negative correlation of miR-34a and miR-34c expression with AR levels. Our findings establish that miRNAs interacting with the long 3′UTR of the AR gene are important regulators of AR protein levels, with implications for developing new therapeutic strategies to inhibit AR function and androgen-dependent cell growth. Cancer Res; 71(5); 1956–67. ©2011 AACR.