bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from Protein Kinase Cβ Is an Effective Target for Chemoprevention of Colon Cancer
Authors: Fields Alan P. , Calcagno Shelly R. , Krishna Murli , Rak Sofija , Leitges Michael , Murray Nicole R.
Published: March 2024

Abstract
Colon cancer develops over a period of 10 to 15 years, providing a window of opportunity for chemoprevention and early intervention. However, few molecular targets for effective colon cancer chemoprevention have been characterized and validated. Protein kinase CβII (PKCβII) plays a requisite role in the initiation of colon carcinogenesis in a preclinical mouse model by promoting proliferation and increased β-catenin accumulation. In this study, we test the hypothesis that PKCβII is an effective target for colon cancer chemoprevention using enzastaurin (LY317615), a PKCβ-selective inhibitor, in a mouse model of colon carcinogenesis. We find that enzastaurin potently reduces azoxymethane-induced colon tumor initiation and progression by inhibiting PKCβII-mediated tumor cell proliferation and β-catenin accumulation. Biochemically, enzastaurin reduces expression of the PKCβII- and β-catenin/T-cell factor–regulated genes PKCβII, cyclooxygenase II, and vascular endothelial growth factor, three genes implicated in colon carcinogenesis. Our results show that enzastaurin is an effective chemopreventive agent in a mouse model of sporadic colon cancer that significantly reduces both tumor initiation and progression by inhibiting expression of proproliferative genes. Thus, PKCβII is an important target for colon cancer chemoprevention and the PKCβ-selective inhibitor enzastaurin may represent an effective chemopreventive agent in patients at high risk for colon cancer. [Cancer Res 2009;69(4):1643–50]
Data from Preferential Induction of EphB4 over EphB2 and Its Implication in Colorectal Cancer Progression
Authors: Kumar S. Ram , Scehnet Jeffrey S. , Ley Eric J. , Singh Jasbir , Krasnoperov Valery , Liu Ren , Manchanda Parmeet K. , Ladner Robert D. , Hawes Debra , Weaver Fred A. , Beart Robert W. , Singh Gagandeep , Nguyen Cu , Kahn Michael , Gill Parkash S.
Published: March 2024

Abstract
The receptor tyrosine kinase EphB2 is expressed by colon progenitor cells; however, only 39% of colorectal tumors express EphB2 and expression levels decline with disease progression. Conversely, EphB4 is absent in normal colon but is expressed in all 102 colorectal cancer specimens analyzed, and its expression level correlates with higher tumor stage and grade. Both EphB4 and EphB2 are regulated by the Wnt pathway, the activation of which is critically required for the progression of colorectal cancer. Differential usage of transcriptional coactivator cyclic AMP-responsive element binding protein–binding protein (CBP) over p300 by the Wnt/β-catenin pathway is known to suppress differentiation and increase proliferation. We show that the β-catenin-CBP complex induces EphB4 and represses EphB2, in contrast to the β-catenin-p300 complex. Gain of EphB4 provides survival advantage to tumor cells and resistance to innate tumor necrosis factor-related apoptosis-inducing ligand–mediated cell death. Knockdown of EphB4 inhibits tumor growth and metastases. Our work is the first to show that EphB4 is preferentially induced in colorectal cancer, in contrast to EphB2, whereby tumor cells acquire a survival advantage. [Cancer Res 2009;69(9):3736–45]
Data from The MET Receptor Tyrosine Kinase Is a Potential Novel Therapeutic Target for Head and Neck Squamous Cell Carcinoma
Authors: Seiwert Tanguy Y. , Jagadeeswaran Ramasamy , Faoro Leonardo , Janamanchi Varalakshmi , Nallasura Vidya , El Dinali Mohamed , Yala Soheil , Kanteti Rajani , Cohen Ezra E.W. , Lingen Mark W. , Martin Leslie , Krishnaswamy Soundararajan , Klein-Szanto Andres , Christensen James G. , Vokes Everett E. , Salgia Ravi
Published: March 2024

Abstract
Recurrent/metastatic head and neck cancer remains a devastating disease with insufficient treatment options. We investigated the MET receptor tyrosine kinase as a novel target for the treatment of head and neck squamous cell carcinoma (HNSCC). MET/phosphorylated MET and HGF expression was analyzed in 121 tissues (HNSCC/normal) by immunohistochemistry, and in 20 HNSCC cell lines by immunoblotting. The effects of MET inhibition using small interfering RNA/two small-molecule inhibitors (SU11274/PF-2341066) on signaling, migration, viability, and angiogenesis were determined. The complete MET gene was sequenced in 66 head and neck cancer tissue samples and eight cell lines. MET gene copy number was determined in 14 cell lines and 23 tumor tissues. Drug combinations of SU11274 with cisplatin or erlotinib were tested in SCC35/HN5 cell lines. Eighty-four percent of the HNSCC samples showed MET overexpression, whereas 18 of 20 HNSCC cell lines (90%) expressed MET. HGF overexpression was present in 45% of HNSCC. MET inhibition with SU11274/PF-2341066 abrogated MET signaling, cell viability, motility/migration in vitro, and tumor angiogenesis in vivo. Mutational analysis of 66 tumor tissues and 8 cell lines identified novel mutations in the semaphorin (T230M/E168D/N375S), juxtamembrane (T1010I/R988C), and tyrosine kinase (T1275I/V1333I) domains (incidence: 13.5%). Increased MET gene copy number was present with >10 copies in 3 of 23 (13%) tumor tissues. A greater-than-additive inhibition of cell growth was observed when combining a MET inhibitor with cisplatin or erlotinib and synergy may be mediated via erbB3/AKT signaling. MET is functionally important in HNSCC with prominent overexpression, increased gene copy number, and mutations. MET inhibition abrogated MET functions, including proliferation, migration/motility, and angiogenesis. MET is a promising, novel target for HNSCC and combination approaches with cisplatin or EGFR inhibitors should be explored. [Cancer Res 2009;69(7):3021–31]
Data from microRNA-205 Regulates HER3 in Human Breast Cancer
Authors: Iorio Marilena V. , Casalini Patrizia , Piovan Claudia , Di Leva Gianpiero , Merlo Andrea , Triulzi Tiziana , Ménard Sylvie , Croce Carlo M. , Tagliabue Elda
Published: March 2024

Abstract
An increasing amount of experimental evidence shows that microRNAs can have a causal role in breast cancer tumorigenesis as a novel class of oncogenes or tumor suppressor genes, depending on the targets they regulate. HER2 overexpression is a hallmark of a particularly aggressive subset of breast tumors, and its activation is strictly dependent on the trans-interaction with other members of HER family; in particular, the activation of the PI3K/Akt survival pathway, so critically important in tumorigenesis, is predominantly driven through phosphorylation of the kinase-inactive member HER3. Here, we show that miR-205, down-modulated in breast tumors compared with normal breast tissue, directly targets HER3 receptor, and inhibits the activation of the downstream mediator Akt. The reintroduction of miR-205 in SKBr3 cells inhibits their clonogenic potential and increases the responsiveness to tyrosine-kinase inhibitors Gefitinib and Lapatinib, abrogating the HER3-mediated resistance and restoring a potent proapoptotic activity. Our data describe miR-205 as a new oncosuppressor gene in breast cancer, able to interfere with the proliferative pathway mediated by HER receptor family. Our study also provides experimental evidence suggesting that miR-205 can improve the responsiveness to specific anticancer therapies. [Cancer Res 2009;69(6):2195–200]
Data from TGF-β1 + EGF-Initiated Invasive Potential in Transformed Human Keratinocytes Is Coupled to a Plasmin/MMP-10/MMP-1–Dependent Collagen Remodeling Axis: Role for PAI-1
Authors: Wilkins-Port Cynthia E. , Ye Qunhui , Mazurkiewicz Joseph E. , Higgins Paul J.
Published: March 2024

Abstract
The phenotypic switching called epithelial-to-mesenchymal transition is frequently associated with epithelial tumor cell progression from a comparatively benign to an aggressive, invasive malignancy. Coincident with the emergence of such cellular plasticity is an altered response to transforming growth factor-β (TGF-β) as well as epidermal growth factor (EGF) receptor amplification. TGF-β in the tumor microenvironment promotes invasive traits largely through reprogramming gene expression, which paradoxically supports matrix-disruptive as well as stabilizing processes. ras-transformed HaCaT II-4 keratinocytes undergo phenotypic changes typical of epithelial-to-mesenchymal transition, acquire a collagenolytic phenotype, and effectively invade collagen type 1 gels as a consequence of TGF-β1 + EGF stimulation in a three-dimensional physiologically relevant model system that monitors collagen remodeling. Enhanced collagen degradation was coupled to a significant increase in matrix metalloproteinase (MMP)-10 expression and involved a proteolytic axis composed of plasmin, MMP-10, and MMP-1. Neutralization of any one component in this cascade inhibited collagen gel lysis. Similarly, addition of plasminogen activator inhibitor type 1 (SERPINE1) blocked collagen degradation as well as the conversion of both proMMP-10 and proMMP-1 to their catalytically active forms. This study therefore identifies an important mechanism in TGF-β1 + EGF-initiated collagen remodeling by transformed human keratinocytes and proposes a crucial upstream role for plasminogen activator inhibitor type 1–dependent regulation in this event. [Cancer Res 2009;69(9):4081–91]
Data from Small Molecule XIAP Inhibitors Enhance TRAIL-Induced Apoptosis and Antitumor Activity in Preclinical Models of Pancreatic Carcinoma
Authors: Vogler Meike , Walczak Henning , Stadel Dominic , Haas Tobias L. , Genze Felicitas , Jovanovic Marjana , Bhanot Umesh , Hasel Cornelia , Möller Peter , Gschwend Jürgen E. , Simmet Thomas , Debatin Klaus-Michael , Fulda Simone
Published: March 2024

Abstract
Evasion of apoptosis is a characteristic feature of pancreatic cancer, a prototypic cancer that is refractory to current treatment approaches. Hence, there is an urgent need to design rational strategies that counter apoptosis resistance. To explore X-linked inhibitor of apoptosis (XIAP) as a therapeutic target in pancreatic cancer, we analyzed the expression of XIAP in pancreatic tumor samples and evaluated the effect of small molecule XIAP inhibitors alone and in combination with tumor necrosis factor–related apoptosis-inducing ligand (TRAIL) against pancreatic carcinoma in vitro and in vivo. Here, we report that XIAP is highly expressed in pancreatic adenocarcinoma samples compared with normal pancreatic ducts. Small molecule XIAP inhibitors synergize with TRAIL to induce apoptosis and to inhibit long-term clonogenic survival of pancreatic carcinoma cells. In contrast, they do not reverse the lack of toxicity of TRAIL on nonmalignant cells in vitro or normal tissues in vivo, pointing to a therapeutic index. Most importantly, XIAP inhibitors cooperate with TRAIL to trigger apoptosis and suppress pancreatic carcinoma growth in vivo in two preclinical models, i.e., the chorioallantoic membrane model and a mouse xenograft model. Parallel immunohistochemical analysis of tumor tissue under therapy reveals that the XIAP inhibitor acts in concert with TRAIL to cause caspase-3 activation and apoptosis. In conclusion, our findings provide, for the first time, evidence in vivo that XIAP inhibitors prime pancreatic carcinoma cells for TRAIL-induced apoptosis and potentiate the antitumor activity of TRAIL against established pancreatic carcinoma. These findings build the rationale for further (pre)clinical development of XIAP inhibitors and TRAIL against pancreatic cancer. [Cancer Res 2009;69(6):2425–34]
Data from Enhanced Antitumor Activity Induced by Adoptive T-Cell Transfer and Adjunctive Use of the Histone Deacetylase Inhibitor LAQ824
Authors: Vo Dan D. , Prins Robert M. , Begley Jonathan L. , Donahue Timothy R. , Morris Lilah F. , Bruhn Kevin W. , de la Rocha Pilar , Yang Meng-Yin , Mok Stephen , Garban Hermes J. , Craft Noah , Economou James S. , Marincola Francesco M. , Wang Ena , Ribas Antoni
Published: March 2024

Abstract
Tumors grow in the presence of antigen-specific T cells, suggesting the existence of intrinsic cancer cell escape mechanisms. We hypothesized that a histone deacetylase (HDAC) inhibitor could sensitize tumor cells to immunotherapy because this class of agents has been reported to increase tumor antigen expression and shift gene expression to a proapoptotic milieu in cancer cells. To test this question, we treated B16 murine melanoma with the combination of the HDAC inhibitor LAQ824 and the adoptive transfer of gp100 melanoma antigen-specific pmel-1 T cells. The combined therapy significantly improved antitumor activity through several mechanisms: (a) increase in MHC and tumor-associated antigen expression by tumor cells; (b) decrease in competing endogenous lymphocytes in recipient mice, resulting in a proliferative advantage for the adoptively transferred cells; and (c) improvement in the functional activity of the adoptively transferred lymphocytes. We confirmed the beneficial effects of this HDAC inhibitor as a sensitizer to immunotherapy in a different model of prophylactic prime-boost vaccination with the melanoma antigen tyrosinase-related protein 2, which also showed a significant improvement in antitumor activity against B16 melanoma. In conclusion, the HDAC inhibitor LAQ824 significantly enhances tumor immunotherapy through effects on target tumor cells as well as improving the antitumor activity of tumor antigen-specific lymphocytes. [Cancer Res 2009;69(22):8693–9]
Data from Endothelial Nitric Oxide Synthase Mediates Lymphangiogenesis and Lymphatic Metastasis
Authors: Lahdenranta Johanna , Hagendoorn Jeroen , Padera Timothy P. , Hoshida Tohru , Nelson Gregory , Kashiwagi Satoshi , Jain Rakesh K. , Fukumura Dai
Published: March 2024

Abstract
Lymphatic metastasis is a critical determinant of cancer prognosis. Recently, several lymphangiogenic molecules such as vascular endothelial growth factor (VEGF)-C and VEGF-D were identified. However, the mechanistic understanding of lymphatic metastasis is still in infancy. Nitric oxide (NO) plays a crucial role in regulating blood vessel growth and function as well as lymphatic vessel function. NO synthase (NOS) expression correlates with lymphatic metastasis. However, causal relationship between NOS and lymphatic metastasis has not been documented. To this end, we first show that both VEGF receptor-2 and VEGF receptor-3 stimulation activate eNOS in lymphatic endothelial cells and that NO donors induce proliferation and/or survival of cultured lymphatic endothelial cells in a dose-dependent manner. We find that an NOS inhibitor, L-NMMA, blocked regeneration of lymphatic vessels. Using intravital microscopy that allows us to visualize the steps of lymphatic metastasis, we show that genetic deletion of eNOS as well as NOS blockade attenuates peritumor lymphatic hyperplasia of VEGF-C–overexpressing T241 fibrosarcomas and decreases the delivery of metastatic tumor cells to the draining lymph nodes. Genetic deletion of eNOS in the host also leads to a decrease in T241 tumor cell dissemination to the lymph nodes and macroscopic lymph node metastasis of B16F10 melanoma. These findings indicate that eNOS mediates VEGF-C–induced lymphangiogenesis and, consequently, plays a critical role in lymphatic metastasis. Our findings explain the correlation between NOS and lymphatic metastasis seen in a number of human tumors and open the door for potential therapies exploiting NO signaling to treat diseases of the lymphatic system. [Cancer Res 2009;69(7):2801–8]
Data from Nucleolar Targeting of RelA(p65) Is Regulated by COMMD1-Dependent Ubiquitination
Authors: Thoms Hazel C. , Loveridge Carolyn J. , Simpson James , Clipson Alexandra , Reinhardt Karina , Dunlop Malcolm G. , Stark Lesley A.
Published: March 2024

Abstract
Stimulation of the NF-κB pathway can have proapoptotic or antiapoptotic consequences, and one mechanism that determines the outcome is the nuclear distribution of RelA. Certain stress stimuli induce nucleolar accumulation of RelA thereby mediating apoptosis, whereas others induce nucleoplasmic accumulation and inhibition of apoptosis. Here we investigated the mechanisms that regulate the nuclear distribution of RelA, specifically, the role of the ubiquitin/proteasome system. We found that stress-induced nucleolar translocation of RelA is preceded by ubiquitination of the protein. We also found that chemical proteasome inhibitors induce the ubiquitination and nucleolar translocation of RelA and that this is required for the apoptotic response to these agents. We show that the RelA nucleolar localization signal (amino acids 27–30) is a critical domain for ubiquitination of the protein but that the lysine residue within this motif is not a direct target. We show that RelA binds COMMD1, the rate-limiting component of the RelA ubiquitin ligase complex, in response to stress. Furthermore, we show that overexpression of COMMD1 promotes stress-mediated nucleolar targeting of RelA, whereas knockdown of COMMD1 blocks this effect, causing RelA to remain in the nucleoplasm. These data identify a new role for COMMD1 in regulating the nuclear/nucleolar distribution of RelA and suggest that ubiquitination acts as a signal for transport of RelA to the nucleolus. These findings have relevance to the design of chemopreventative/anticancer agents that act by targeting RelA to the nucleolar compartment. Cancer Res; 70(1); 139–49
Data from miR-205 Exerts Tumor-Suppressive Functions in Human Prostate through Down-regulation of Protein Kinase Cε
Authors: Gandellini Paolo , Folini Marco , Longoni Nicole , Pennati Marzia , Binda Mara , Colecchia Maurizio , Salvioni Roberto , Supino Rosanna , Moretti Roberta , Limonta Patrizia , Valdagni Riccardo , Daidone Maria Grazia , Zaffaroni Nadia
Published: March 2024

Abstract
Limited information is available concerning the expression and role of microRNAs in prostate cancer. In this study, we investigated the involvement of miR-205 in prostate carcinogenesis. Significantly lower miR-205 expression levels were found in cancer than in normal prostate cell lines as well as in tumor compared with matched normal prostate tissues, with a particularly pronounced reduction in carcinomas from patients with local-regionally disseminated disease. Restoring the expression of miR-205 in prostate cancer cells resulted in cell rearrangements consistent with a mesenchymal-to-epithelial transition, such as up-regulation of E-cadherin and reduction of cell locomotion and invasion, and in the down-regulation of several oncogenes known to be involved in disease progression (i.e., interleukin 6, caveolin-1, EZH2). Our evidence suggests that these events are driven by the concurrent repression of specific predicted miR-205 targets, namely N-chimaerin, ErbB3, E2F1, E2F5, ZEB2, and protein kinase Cε. Strikingly, the latter seemed to play a direct role in regulating epithelial-to-mesenchymal transition. In fact, its down-regulation led to a cell phenotype largely reminiscent of that of cells ectopically expressing miR-205. Overall, we showed for the first time that miR-205 exerts a tumor-suppressive effect in human prostate by counteracting epithelial-to-mesenchymal transition and reducing cell migration/invasion, at least in part through the down-regulation of protein kinase Cε. [Cancer Res 2009;69(6):2287–95]
Data from Epithelial-to-Mesenchymal Transition and Ovarian Tumor Progression Induced by Tissue Transglutaminase
Authors: Shao Minghai , Cao Liyun , Shen Changyu , Satpathy Minati , Chelladurai Bhadrani , Bigsby Robert M. , Nakshatri Harikrishna , Matei Daniela
Published: March 2024

Abstract
Tissue transglutaminase (TG2), an enzyme that catalyzes Ca2+-dependent aggregation and polymerization of proteins, is overexpressed in ovarian cancer cells and tumors. We previously reported that TG2 facilitates tumor dissemination using an i.p. xenograft model. Here we show that TG2 modulates epithelial-to-mesenchymal transition (EMT), contributing to increased ovarian cancer cell invasiveness and tumor metastasis. By using stable knockdown and overexpression in epithelial ovarian cancer cells, we show that TG2 induces a mesenchymal phenotype, characterized by cadherin switch and invasive behavior in a Matrigel matrix. This is mediated at the transcriptional level by altering the expression levels and function of several transcriptional repressors, including Zeb1. One mechanism through which TG2 induces Zeb1 is by activating the nuclear factor-κB complex. The effects of TG2 on ovarian cancer cell phenotype and invasiveness translate into increased tumor formation and metastasis in vivo, as assessed by an orthotopic ovarian xenograft model. Highly expressed in ovarian tumors, TG2 promotes EMT and enhances ovarian tumor metastasis by activating oncogenic signaling. [Cancer Res 2009;69(24):9192–201]
Data from Microenvironmental Independence Associated with Tumor Progression
Authors: Anderson Alexander R.A. , Hassanein Mohamed , Branch Kevin M. , Lu Jenny , Lobdell Nichole A. , Maier Julie , Basanta David , Weidow Brandy , Narasanna Archana , Arteaga Carlos L. , Reynolds Albert B. , Quaranta Vito , Estrada Lourdes , Weaver Alissa M.
Published: March 2024

Abstract
Tumor-microenvironment interactions are increasingly recognized to influence tumor progression. To understand the competitive dynamics of tumor cells in diverse microenvironments, we experimentally parameterized a hybrid discrete-continuum mathematical model with phenotypic trait data from a set of related mammary cell lines with normal, transformed, or tumorigenic properties. Surprisingly, in a resource-rich microenvironment, with few limitations on proliferation or migration, transformed (but not tumorigenic) cells were most successful and outcompeted other cell types in heterogeneous tumor simulations. Conversely, constrained microenvironments with limitations on space and/or growth factors gave a selective advantage to phenotypes derived from tumorigenic cell lines. Analysis of the relative performance of each phenotype in constrained versus unconstrained microenvironments revealed that, although all cell types grew more slowly in resource-constrained microenvironments, the most aggressive cells were least affected by microenvironmental constraints. A game theory model testing the relationship between microenvironment resource availability and competitive cellular dynamics supports the concept that microenvironmental independence is an advantageous cellular trait in resource-limited microenvironments. [Cancer Res 2009;69(22):8797–806]
Data from Suppression of Human Solid Tumor Growth in Mice by Intratumor and Systemic Inoculation of Histidine-Rich and pH-Dependent Host Defense–like Lytic Peptides
Authors: Makovitzki Arik , Fink Avner , Shai Yechiel
Published: March 2024

Abstract
Previously, we reported that intratumor or systemic inoculation of a cationic 15-mer, innate immunity-like lytic peptide composed of d- and l-amino acids ([D]-K6L9) caused growth arrest of 22RV1 prostate carcinoma xenografts in a mouse model. However, despite its therapeutic potential, this peptide has significant systemic toxicity at concentrations slightly higher than the therapeutic one. Here, we used the acidic environment created by solid tumors as a trigger to activate anticancer lytic peptides by making them cationic only at low pH levels. We achieved this selectivity by substituting lysines (pKa, ∼10.5) for histidines (pKa, ∼6.1) in the parental peptide [D]-K6L9. Histidine is protonated below pH 7. For that purpose, we replaced either three or all six lysines in the parental peptide with histidines to obtain the peptides [D]-K3H3L9 and [D]-H6L9. Interestingly, in vitro experiments showed pH-dependent activity only with [D]-H6L9 mainly toward cancer cell lines. However, both peptides showed reduced systemic toxicity compared with the parental peptide. Intratumor and systemic inoculation of these peptides resulted in a significant decrease in the 22RV1 prostate cancer tumor volume and systemic secretion of prostate-specific antigen in a xenograft mice model. Moreover, histologic modifications revealed a significant reduction in new blood vessels selectively in tumor tissues after treatment with the peptides compared with the untreated tumors. The lytic mode of action of these new peptides, which makes it difficult for the cancer cells to develop resistance, and their selective and pH-dependent activity make them potential candidates for treatment of solid cancer tumors. [Cancer Res 2009;69(8):3458–63]
Data from Fingerprint of Cell Metabolism in the Experimentally Observed Interstitial pH and pO2 in Solid Tumors
Authors: Molavian Hamid R. , Kohandel Mohammad , Milosevic Michael , Sivaloganathan Sivabal
Published: March 2024

Abstract
Understanding cancer cell metabolism and targeting associated pathways is a field of increasing interest. Helmlinger and colleagues measured average pH and pO2 as functions of distance from a single blood vessel on the micrometer scale. We show that these results provide unique insight into cancer cell metabolism in vivo when combined with an appropriate mathematical model. We calculate pH as a function of distance from a single blood vessel and for a given metabolism while incorporating a single CO2 buffer with effective diffusion constants. By assuming that cancer cell metabolism is dominated by respiration with a smaller component of glycolysis in the normoxic state, by more balanced respiration and glycolysis in the hypoxic state, and by glycolysis alone in the anoxic state, we are able to semiquantitatively derive the experimental results of Helmlinger and colleagues. We also apply our model to glycolysis-impaired metabolism and show that the low pH and high pO2 observed in these tumors may be related to the substantial shift from a respiration-dominated metabolism to one in which glutaminolysis dominates. Based on this, we propose an in vivo experimental measurement of pH in a glycolysis-impaired tumor to validate the modeling results. [Cancer Res 2009;69(23):9141–7]
Data from The Fibroblast Growth Factor Receptor Inhibitor PD173074 Blocks Small Cell Lung Cancer Growth In vitro and In vivo
Authors: Pardo Olivier E. , Latigo John , Jeffery Rosemary E. , Nye Emma , Poulsom Richard , Spencer-Dene Bradley , Lemoine Nick R. , Stamp Gordon W. , Aboagye Eric O. , Seckl Michael J.
Published: March 2024

Abstract
Lung cancer is the commonest cancer killer. Small cell lung cancer (SCLC) is initially chemosensitive, but rapidly relapses in a chemoresistant form with an overall survival of <5%. Consequently, novel therapies are urgently required and will likely arise from an improved understanding of the disease biology. Our previous work showed that fibroblast growth factor-2 induces proliferation and chemoresistance in SCLC cells. Here, we show that the selective fibroblast growth factor receptor (FGFR) inhibitor PD173074 blocks H-510 and H-69 SCLC proliferation and clonogenic growth in a dose-dependent fashion and prevents FGF-2–induced chemoresistance. These effects correlate with the inhibition of both FGFR1 and FGFR2 transphosphorylation. We then determined the efficacy of daily oral administration of PD173074 for 28 days in two human SCLC models. In the H-510 xenograft, tumor growth was impaired similar to that seen with single-agent cisplatin administration, increasing median survival compared with control sham–treated animals. Crucially, the effect of cisplatin was significantly potentiated by coadministration of PD173074. More dramatically, in H-69 xenografts, PD173074 induced complete responses lasting >6 months in 50% of mice. These effects were not a consequence of disrupted tumor vasculature but instead correlated with increased apoptosis (caspase 3 and cytokeratin 18 cleavage) in excised tumors. Moreover, in vivo imaging with 3′-deoxy-3′-[18F]fluorothymidine–positron emission tomography ([18F]FLT-PET) showed decreased intratumoral proliferation in live animals treated with the compound at 7 to 14 days. Our results suggest that clinical trials of FGFR inhibitors should be undertaken in patients with SCLC and that [18F]FLT-PET imaging could provide early in vivo evidence of response. [Cancer Res 2009;69(22):8645–51]
Data from Design of Agonistic Altered Peptides for the Robust Induction of CTL Directed towards H-2Db in Complex with the Melanoma-Associated Epitope gp100
Authors: van Stipdonk Marianne J.B. , Badia-Martinez Daniel , Sluijter Marjolein , Offringa Rienk , van Hall Thorbald , Achour Adnane
Published: March 2024

Abstract
Immunogenicity of tumor-associated antigens (TAA) is often weak because many TAA are autoantigens for which the T-cell repertoire is sculpted by tolerance mechanisms. Substitutions at main anchor positions to increase the complementarity between the peptide and the MHC class I (MHC-I) binding cleft constitute a common procedure to improve binding capacity and immunogenicity of TAA. However, such alterations are tailored for each MHC-I allele and may recruit different CTL specificities through conformational changes in the targeted peptides. Comparative analysis of substituted melanoma-differentiation antigen gp100 in complex with H-2Db revealed that combined introduction of glycine and proline residues at the nonanchor positions 2 and 3, respectively, resulted in an agonistic altered peptide with dramatically enhanced binding affinity, stability, and immunogenicity of this TAA. Peptide vaccination using the p2Gp3P-altered peptide version of gp100 induced high frequencies of melanoma-specific CTL in the endogenous CD8+ repertoire. Crystal structure analysis of MHC/peptide complexes revealed that the conformation of the modified p2Gp3P-peptide was similar to the wild-type peptide, and indicated that this mimotope was stabilized through interactions between peptide residue p3P and the tyrosine residue Y159 that is conserved among most known MHC-I molecules throughout mammalian species. Our results may provide an alternative approach to enhance MHC stabilization capacity and immunogenicity of low-affinity peptides for induction of robust tumor-specific CTL. [Cancer Res 2009;69(19):7784–92]
Data from Phospholipase D1 Drives a Positive Feedback Loop to Reinforce the Wnt/β-Catenin/TCF Signaling Axis
Authors: Kang Dong Woo , Lee Soung-Hoon , Yoon Jeong Whan , Park Won-Sang , Choi Kang-Yell , Min Do Sik
Published: March 2024

Abstract
Activation of the Wnt signaling pathway occurs frequently in human cancers, but an understanding of the targets and regulation of this important pathway remains incomplete. In this study, we report that phospholipase D (PLD), a cell survival mediator that is upregulated in cancer, is an important target of the Wnt signaling pathway that functions in a positive feedback loop to reinforce pathway output. PLD1 expression and activity was enhanced by treatment with Wnt3a and glycogen synthase kinase-3 inhibitors, and the Wnt pathway–regulated transcription factors β-catenin and TCF-4 were required for this effect. Three functional TCF-4–binding sites were identified within the PLD1 promoter. Interestingly, suppressing PLD1 blocked the ability of β-catenin to transcriptionally activate PLD1 and other Wnt target genes by preventing β-catenin/TCF-4 complex formation. Conversely, tactics to elevate intracellular levels of phosphatidic acid, the product of PLD1 enzyme activity, enhanced β-catenin/TCF-4 complex formation as well as β-catenin–dependent TCF transcriptional activity. In cell-based assays, PLD1 was necessary for the anchorage-independent growth driven by Wnt/β-catenin signaling, whereas β-catenin/TCF-4 was necessary for the anchorage-independent growth driven by PLD1 activation. Taken together, our findings define a function for PLD1 in a positive feedback loop of Wnt/β-catenin/TCF-4 signaling that provides new mechanistic insights into cancer, with implications of novel strategies to disrupt Wnt signaling in cancer. Cancer Res; 70(10); 4233–42. ©2010 AACR.
Data from γ-Secretase Inhibitors Enhance Temozolomide Treatment of Human Gliomas by Inhibiting Neurosphere Repopulation and Xenograft Recurrence
Authors: Gilbert Candace A. , Daou Marie-Claire , Moser Richard P. , Ross Alonzo H.
Published: March 2024

Abstract
Malignant gliomas are treated with a combination of surgery, radiation, and temozolomide (TMZ), but these therapies ultimately fail due to tumor recurrence. In glioma cultures, TMZ treatment significantly decreases neurosphere formation; however, a small percentage of cells survive and repopulate the culture. A promising target for glioma therapy is the Notch signaling pathway. Notch activity is upregulated in many gliomas and can be suppressed using γ-secretase inhibitors (GSI). Using a neurosphere recovery assay and xenograft experiments, we analyzed if the addition of GSIs with TMZ treatment could inhibit repopulation and tumor recurrence. We show that TMZ + GSI treatment decreased neurosphere formation and inhibited neurosphere recovery. This enhancement of TMZ treatment occurred through inhibition of the Notch pathway and depended on the sequence of drug administration. In addition, ex vivo TMZ + GSI treatment of glioma xenografts in immunocompromised mice extended tumor latency and survival, and in vivo TMZ + GSI treatment blocked tumor progression in 50% of mice with preexisting tumors. These data show the importance of the Notch pathway in chemoprotection and repopulation of TMZ-treated gliomas. The addition of GSIs to current treatments is a promising approach to decrease brain tumor recurrence. Cancer Res; 70(17); 6870–9. ©2010 AACR.
Data from Recognition and Killing of Brain Tumor Stem-Like Initiating Cells by CD8+ Cytolytic T Cells
Authors: Brown Christine E. , Starr Renate , Martinez Catalina , Aguilar Brenda , D'Apuzzo Massimo , Todorov Ivan , Shih Chu-Chih , Badie Behnam , Hudecek Michael , Riddell Stanley R. , Jensen Michael C.
Published: March 2024

Abstract
Solid tumors contain a subset of stem-like cells that are resistant to the cytotoxic effects of chemotherapy/radiotherapy, but their susceptibility to cytolytic T lymphocyte (CTL) effector mechanisms has not been well characterized. Using a panel of early-passage human brain tumor stem/initiating cell (BTSC) lines derived from high-grade gliomas, we show that BTSCs are subject to immunologic recognition and elimination by CD8+ CTLs. Compared with serum-differentiated CD133low tumor cells and established glioma cell lines, BTSCs are equivalent with respect to expression levels of HLA class I and ICAM-1, similar in their ability to trigger degranulation and cytokine synthesis by antigen-specific CTLs, and equally susceptible to perforin-dependent CTL-mediated cytolysis. BTSCs are also competent in the processing and presentation of antigens as evidenced by the killing of these cells by CTL when antigen is endogenously expressed. Moreover, we show that CTLs can eliminate all BTSCs with tumor-initiating activity in an antigen-specific manner in vivo. Current models predict that curative therapies for many cancers will require the elimination of the stem/initiating population, and these studies lay the foundation for developing immunotherapeutic approaches to eradicate this tumor population. [Cancer Res 2009;69(23):8886–93]
Data from A Useful Approach to Identify Novel Small-Molecule Inhibitors of Wnt-Dependent Transcription
Authors: Ewan Kenneth , Pająk Bożena , Stubbs Mark , Todd Helen , Barbeau Olivier , Quevedo Camilo , Botfield Hannah , Young Rodrigo , Ruddle Ruth , Samuel Lee , Battersby Alysia , Raynaud Florence , Allen Nicholas , Wilson Stephen , Latinkic Branko , Workman Paul , McDonald Edward , Blagg Julian , Aherne Wynne , Dale Trevor
Published: March 2024

Abstract
The Wnt signaling pathway is frequently deregulated in cancer due to mutations in genes encoding APC, β-catenin, and axin. To identify small-molecule inhibitors of Wnt signaling as potential therapeutics, a diverse chemical library was screened using a transcription factor reporter cell line in which the activity of the pathway was induced at the level of Disheveled protein. A series of deconvolution studies was used to focus on three compound series that selectively killed cancer cell lines with constitutive Wnt signaling. Activities of the compounds included the ability to induce degradation of β-catenin that had been stabilized by a glycogen synthase kinase-3 (GSK-3) inhibitor. This screen illustrates a practical approach to identify small-molecule inhibitors of Wnt signaling that can seed the development of agents suitable to treat patients with Wnt-dependent tumors. Cancer Res; 70(14); 5963–73. ©2010 AACR.
Data from A Functional Receptor for B-Cell–Activating Factor Is Expressed on Human Acute Lymphoblastic Leukemias
Authors: Parameswaran Reshmi , Müschen Markus , Kim Yong-mi , Groffen John , Heisterkamp Nora
Published: March 2024

Abstract
B-lineage acute lymphoblastic leukemia (ALL) arises by transformation of a progenitor (pre-B) cell. Cure rates in adults remain low and treatment is complicated by support provided by the microenvironment to the leukemic cells, indicating an urgent need to better understand the factors that promote their survival. B-cell–activating factor (BAFF) and its receptor BAFF-R are important for survival and growth of mature normal and malignant B cells but are not expressed on pre-B cells. Unexpectedly, all cells in the primary Philadelphia chromosome (Ph)–positive and Ph-negative ALL samples tested were positive for high BAFF-R cell surface expression. BAFF-R was fully competent to bind BAFF, and stimulation of the receptor activated both the classic and the noncanonical NF-κB pathways. Recombinant BAFF supported survival of the ALL cells in the absence of stroma, and it significantly attenuated the rate of apoptosis caused by exposure to nilotinib, a drug used therapeutically to treat Ph-positive ALLs. Surprisingly, BAFF mRNA and protein were also expressed in the same cells but BAFF was not shed into the medium. Our report is the first showing universal expression of BAFF-R by pre-B ALL cells and opens the possibility of blocking its function as an adjuvant therapeutic strategy. Cancer Res; 70(11); 4346–56. ©2010 AACR.
Data from Atoh1 Inhibits Neuronal Differentiation and Collaborates with Gli1 to Generate Medulloblastoma-Initiating Cells
Authors: Ayrault Olivier , Zhao Haotian , Zindy Frederique , Qu Chunxu , Sherr Charles J. , Roussel Martine F.
Published: March 2024

Abstract
The morphogen and mitogen Sonic Hedgehog (Shh) activates a Gli1-dependent transcription program that drives proliferation of granule neuron progenitors (GNP) within the external germinal layer of the postnatally developing cerebellum. Medulloblastomas with mutations activating the Shh signaling pathway preferentially arise within the external germinal layer, and the tumor cells closely resemble GNPs. Atoh1/Math1, a basic helix-loop-helix transcription factor essential for GNP histogenesis, does not induce medulloblastomas when expressed in primary mouse GNPs that are explanted from the early postnatal cerebellum and transplanted back into the brains of naïve mice. However, enforced expression of Atoh1 in primary GNPs enhances the oncogenicity of cells overexpressing Gli1 by almost three orders of magnitude. Unlike Gli1, Atoh1 cannot support GNP proliferation in the absence of Shh signaling and does not govern expression of canonical cell cycle genes. Instead, Atoh1 maintains GNPs in a Shh-responsive state by regulating genes that trigger neuronal differentiation, including many expressed in response to bone morphogenic protein-4. Therefore, by targeting multiple genes regulating the differentiation state of GNPs, Atoh1 collaborates with the pro-proliferative Gli1-dependent transcriptional program to influence medulloblastoma development. Cancer Res; 70(13); 5618–27. ©2010 AACR.
Data from Transplanting Normal Vascular Proangiogenic Cells to Tumor-Bearing Mice Triggers Vascular Remodeling and Reduces Hypoxia in Tumors
Authors: Sasajima Junpei , Mizukami Yusuke , Sugiyama Yoshiaki , Nakamura Kazumasa , Kawamoto Toru , Koizumi Kazuya , Fujii Rie , Motomura Wataru , Sato Kazuya , Suzuki Yasuaki , Tanno Satoshi , Fujiya Mikihiro , Sasaki Katsunori , Shimizu Norihiko , Karasaki Hidenori , Kono Toru , Kawabe Jun-ichi , Ii Masaaki , Yoshiara Hiroki , Kamiyama Naohisa , Ashida Toshifumi , Bardeesy Nabeel , Chung Daniel C. , Kohgo Yutaka
Published: March 2024

Abstract
Blood vessels deliver oxygen and nutrients to tissues, and vascular networks are spatially organized to meet the metabolic needs for maintaining homeostasis. In contrast, the vasculature of tumors is immature and leaky, resulting in insufficient delivery of nutrients and oxygen. Vasculogenic processes occur normally in adult tissues to repair “injured” blood vessels, leading us to hypothesize that bone marrow mononuclear cells (BMMNC) may be able to restore appropriate vessel function in the tumor vasculature. Culturing BMMNCs in endothelial growth medium resulted in the early outgrowth of spindle-shaped attached cells expressing CD11b/Flt1/Tie2/c-Kit/CXCR4 with proangiogenic activity. Intravenous administration of these cultured vascular proangiogenic cells (VPC) into nude mice bearing pancreatic cancer xenografts and Pdx1-Cre;LSL-KrasG12D;p53lox/+ genetically engineered mice that develop pancreatic ductal adenocarcinoma significantly reduced areas of hypoxia without enhancing tumor growth. The resulting vasculature structurally mimicked normal vessels with intensive pericyte coverage. Increases in vascularized areas within VPC-injected xenografts were visualized with an ultrasound diagnostic system during injection of a microbubble-based contrast agent (Sonazoid), indicating a functional “normalization” of the tumor vasculature. In addition, gene expression profiles in the VPC-transplanted xenografts revealed a marked reduction in major factors involved in drug resistance and “stemness” of cancer cells. Together, our findings identify a novel alternate approach to regulate abnormal tumor vessels, offering the potential to improve the delivery and efficacy of anticancer drugs to hypoxic tumors. Cancer Res; 70(15); 6283–92. ©2010 AACR.
Data from HuR Regulates β-Tubulin Isotype Expression in Ovarian Cancer
Authors: Raspaglio Giuseppina , De Maria Ilaria , Filippetti Flavia , Martinelli Enrica , Zannoni Gian Franco , Prislei Silvia , Ferrandina Gabriella , Shahabi Shohreh , Scambia Giovanni , Ferlini Cristiano
Published: March 2024

Abstract
The supply of oxygen and nutrients to solid tumors is inefficient because cancer tissues have an inadequate number of microvessels, thus inducing the selective growth of the most aggressive cancer cells. This explains why many of the factors underlying a poor prognosis are induced in hypoxic/hypoglycemic conditions. Among these factors, a prominent role in several solid tumors is played by the class III β-tubulin gene (TUBB3). The study described here reveals that glucose deprivation enhances TUBB3 expression at both the gene and protein levels in A2780 ovarian cancer cells. In silico analysis of TUBB3 mRNA sequence predicted a putative binding site for the RNA-binding protein Hu antigen (HuR) in the 3′ flanking untranslated region. A hypoglycemic-dependent engagement of this site was shown using RNA pull-down and ribonucleoimmunoprecipitation techniques. Thereafter, HuR gene silencing revealed that TUBB3 translation is HuR dependent in hypoglycemia because HuR silencing inhibited the entry of TUBB3 mRNA into cytoskeletal and free polysomes. Finally, the clinical value of this finding was assessed in a clinical cohort of 46 ovarian cancer patients in whom it was found that HuR cytoplasmic staining was associated with high levels of TUBB3 and poor survival. Cancer Res; 70(14); 5891–900. ©2010 AACR.
Data from Plasma Fibronectin Promotes Lung Metastasis by Contributions to Fibrin Clots and Tumor Cell Invasion
Authors: Malik Gunjan , Knowles Lynn M. , Dhir Rajiv , Xu Shuping , Yang Shuting , Ruoslahti Erkki , Pilch Jan
Published: March 2024

Abstract
The attachment of circulating tumor cells to the blood vessels of distant organs is an important step in metastasis. We show here that experimental lung metastasis by two cell lines, B16F1 melanoma and 3LL lung carcinoma, is greatly reduced in transgenic mice that lack plasma fibronectin. This multifunctional adhesive glycoprotein becomes cross-linked to fibrin during clotting. Here, we report that eliminating plasma fibronectin from the blood circulation reverses the prometastatic effects of blood clotting and tumor cell integrin αvβ3. In vitro studies showed that fibrin-fibronectin complexes, but not purified fibrin, supported tumor cell attachment and invasion. These functions correlate with the ability of fibrin-fibronectin complexes to induce the activation of integrin αvβ3. Our findings reveal an important contribution of plasma fibronectin in lung metastasis. Furthermore, they suggest that the previously noted effects of blood clotting on lung metastasis might be mediated in part by a fibronectin-αvβ3 integrin axis, in which plasma fibronectin has to be incorporated into the blood clot. Cancer Res; 70(11); 4327–34. ©2010 AACR.
Data from Akt3-Mediated Resistance to Apoptosis in B-RAF–Targeted Melanoma Cells
Authors: Shao Yongping , Aplin Andrew E.
Published: March 2024

Abstract
Melanoma cells are highly resistant to anoikis, a form of apoptosis induced in nonadherent/inappropriate adhesion conditions. Depleting B-RAF or the prosurvival Bcl-2 family protein Mcl-1 renders mutant B-RAF melanoma cells susceptible to anoikis. In this study, we examined the effect of targeting B-RAF on the survival of primary stage melanoma cells cultured in three-dimensional type I collagen gels, which partially mimics the dermal microenvironment. Depletion/inhibition of B-RAF with small interfering RNA or the mutant B-RAF inhibitor, PLX4720, induced apoptosis of mutant B-RAF melanoma cells in three-dimensional collagen. Apoptosis was dependent on two upregulated BH3-only proteins, Bim-EL and Bmf, and was inhibited by ectopic Mcl-1 expression. Akt3 activation has been associated with the survival of melanoma cells. Mutant B-RAF melanoma cells ectopically expressing a constitutively activated form of Akt3 or endogenously expressing mutant Akt3 were protected from apoptosis induced by B-RAF knockdown or PLX4720 treatment. Furthermore, intrinsically resistant metastatic melanoma cells displayed elevated Akt phosphorylation in three-dimensional collagen and were rendered susceptible to PLX4720 by Akt3 knockdown. Importantly, myristylated Akt3 prevented B-RAF targeting–induced upregulation of Bim-EL and Bmf in three-dimensional collagen and partially protected Mcl-1–depleted cells from apoptosis. These findings delineate how mutant B-RAF protects melanoma cells from apoptosis and provide insight into possible resistance mechanisms to B-RAF inhibitors. Cancer Res; 70(16); 6670–81. ©2010 AACR.
Data from Identification of the ENT1 Antagonists Dipyridamole and Dilazep as Amplifiers of Oncolytic Herpes Simplex Virus-1 Replication
Authors: Passer Brent J. , Cheema Tooba , Zhou Bingsen , Wakimoto Hiroaki , Zaupa Cecile , Razmjoo Mani , Sarte Jason , Wu Shulin , Wu Chin-lee , Noah James W. , Li Qianjun , Buolamwini John K. , Yen Yun , Rabkin Samuel D. , Martuza Robert L.
Published: March 2024

Abstract
Oncolytic herpes simplex virus-1 (oHSV) vectors selectively replicate in tumor cells, where they kill through oncolysis while sparing normal cells. One of the drawbacks of oHSV vectors is their limited replication and spread to neighboring cancer cells. Here, we report the outcome of a high-throughput chemical library screen to identify small-molecule compounds that augment the replication of oHSV G47Δ. Of the 2,640-screened bioactives, 6 compounds were identified and subsequently validated for enhanced G47Δ replication. Two of these compounds, dipyridamole and dilazep, interfered with nucleotide metabolism by potently and directly inhibiting the equilibrative nucleoside transporter-1 (ENT1). Replicative amplification promoted by dipyridamole and dilazep were dependent on HSV mutations in ICP6, the large subunit of ribonucleotide reductase. Our results indicate that ENT1 antagonists augment oHSV replication in tumor cells by increasing cellular ribonucleoside activity. Cancer Res; 70(10); 3890–5. ©2010 AACR.