bluuebunny/crossref_metadata_2025 huggingface dataset:
Data from IGFBP-3 Is a Metastasis Suppression Gene in Prostate Cancer
Authors: Mehta Hemal H. , Gao Qinglei , Galet Colette , Paharkova Vladislava , Wan Junxiang , Said Jonathan , Sohn Joanne J. , Lawson Gregory , Cohen Pinchas , Cobb Laura J. , Lee Kuk-Wha
Published: March 2024

Abstract
The insulin-like growth factor binding protein IGFBP-3 is a proapoptotic and antiangiogenic protein in prostate cancer (CaP). Epidemiologic studies suggest that low IGFBP-3 is associated with greater risk of aggressive, metastatic prostate cancers, but in vivo functional data are lacking. Here we show that mice that are genetically deficient in IGFBP-3 exhibit weaker growth of primary prostate tumors but higher incidence of metastatic disease. Prostates in IGFBP-3 knockout mice (IGFBP-3KO mice) failed to undergo apoptosis after castration. Spontaneous prostate tumors did not develop in IGFBP-3KO mice, but splenic lymphomas occurred in 23% of female IGFBP-3KO mice by 80 weeks of age. To assess the effects of IGFBP-3 deficiency on prostate cancer development, we crossed IGFBP-3KO mice with a c-Myc–driven model of CaP that develops slow-growing, nonmetastatic tumors. By 24 weeks of age, well-differentiated prostate cancers were observed in all mice regardless of IGFBP-3 status. However, by 80 weeks of age IGFBP-3KO mice tended to exhibit larger prostate tumors than control mice. More strikingly, lung metastases were observed at this time in 55% of the IGFBP-3KO mice but none in the control animals. Cell lines established from IGFBP-3KO:Myc tumors displayed more aggressive phenotypes in proliferation, invasion, and colony formation assays, relative to control Myc tumor cell lines. In addition, Myc:IGFBP-3KO cells exhibited evidence of epithelial–mesenchymal transition. Our findings established a function for IGFBP-3 in suppressing metastasis in prostate cancer, and they also offered the first reported transgenic model of spontaneous metastatic prostate cancer for studies of this advanced stage of disease. Cancer Res; 71(15); 5154–63. ©2011 AACR.
Data from Keap1 Mutations and Nrf2 Pathway Activation in Epithelial Ovarian Cancer
Authors: Konstantinopoulos Panagiotis A. , Spentzos Dimitrios , Fountzilas Elena , Francoeur Nancy , Sanisetty Srisowmya , Grammatikos Alexandros P. , Hecht Jonathan L. , Cannistra Stephen A.
Published: March 2024

Abstract
Resistance to platinum-based chemotherapy develops in the majority of patients with epithelial ovarian cancer (EOC). Platinum compounds form electrophilic intermediates that mediate DNA cross-linking and induce double-strand DNA breaks. Because the cellular response to electrophilic xenobiotics is partly mediated by Keap1–Nrf2 pathway, we evaluated the presence of Kelch-like ECH–associated protein 1 (Keap1) mutations and NF-E2–related factor 2 (Nrf2) pathway activation in EOC and correlated these with platinum resistance and clinical outcome. Nrf2 immunohistochemistry revealed nuclear localization (a surrogate of pathway activation) in over half of EOC patient specimens examined, with more common occurrence in the clear cell EOC subtype. Quantitative real-time PCR revealed that Nrf2 target genes were upregulated in tumors with nuclear positivity for Nrf2. Microarray analysis also showed upregulation of Nrf2 target genes in clear cell EOCs compared with other EOC subtypes. In addition, Keap1 sequence analysis revealed genetic mutations in 29% of clear cell samples and 8% of nonclear cell tumors. RNAi-mediated knockdown of Keap1 was associated with Nrf2 pathway activation and resistance to carboplatin in vitro. Importantly, patients with evidence of Nrf2 pathway activation had fewer complete clinical responses to platinum-based therapy, were enriched for platinum resistance, and had shorter median overall survival compared with those who did not show evidence of Nrf2 pathway activation. Our findings identify Keap1 mutations in EOC and they suggest a previously unrecognized role for the Keap1–Nrf2 pathway in mediating chemotherapeutic responses in this disease. Cancer Res; 71(15); 5081–9. ©2011 AACR.
Data from Combination of PI3K/mTOR Inhibitors: Antitumor Activity and Molecular Correlates
Authors: Mazzoletti Marco , Bortolin Francesca , Brunelli Laura , Pastorelli Roberta , Di Giandomenico Silvana , Erba Eugenio , Ubezio Paolo , Broggini Massimo
Published: March 2024

Abstract
The phosphatidylinositol-3-kinase (PI3K)/Akt/mTOR pathway is a major target for cancer therapy. As a strategy to induce the maximal inhibition of this pathway in cancer cells, we combined allosteric mTOR inhibitors (rapamycin and RAD001) with a dual PI3K/mTOR kinase inhibitor (PI-103). Both in vitro and in vivo, the combination exhibited more activity than single agents in human ovarian and prostate cancer cells that harbor alterations in the pathway. At the molecular level, combined inhibition of mTOR prevented the rebound activation of Akt that is seen after treatment with rapamycin and its analogues and caused more sustained inhibition of Akt phosphorylation. Furthermore, the combination strongly inhibited the expression of PI3K/Akt/mTOR downstream proteins. In particular, it showed greater activity than the single agents in inhibiting the phosphorylation of 4EBP1, both in vitro and in vivo, resulting in selective inhibition of CAP-dependent translation. A proteomic approach was used to confirm the identification of c-Myc as the key regulator for the reduction in downstream proteins affected by the combined inhibition of mTOR. In conclusion, the combination of a catalytic and an allosteric inhibitor of mTOR shows greater activity, without a concomitant increase in toxicity, than either drug alone, and this may have therapeutic implications for inhibiting this pathway in the clinical setting. Cancer Res; 71(13); 4573–84. ©2011 AACR.
Data from Plasminogen Activator uPA Is a Direct Transcriptional Target of the JAG1-Notch Receptor Signaling Pathway in Breast Cancer
Authors: Shimizu Mamiko , Cohen Brenda , Goldvasser Pavel , Berman Hal , Virtanen Carl , Reedijk Michael
Published: March 2024

Abstract
Aberrant activation of the Notch receptor signaling pathway and overexpression of the Notch ligand JAG1 are associated with poor outcome in breast cancer. The plasminogen activator system, which includes urokinase-type plasminogen activator (uPA), has been validated as a marker of recurrence, high metastasis risk and death in breast malignancy. By using microarray profiling of breast cancer cell lines that had undergone siRNA-mediated abrogation of Notch signaling we uncovered a link between activated Notch signaling and uPA expression. An association between elevated expression of the Notch ligand JAG1, uPA, and the basal-like breast cancer subtype was confirmed in breast cancer cell lines. The association between JAG1 and uPA expression persisted in a survey of primary carcinomas of the breast. We found that Notch knockdown reduced transcription of uPA and phenocopied uPA knockdown in breast cancer cells. Through mutational analysis we identified a CBF-1 binding site in the uPA promoter that is required for direct transcriptional regulation by Notch. These data suggest that JAG1-induced Notch activation results in breast cancer progression through upregulation of the plasminogen activator system, directly linking these 2 important pathways of poor prognosis. Cancer Res; 71(1); 277–86. ©2010 AACR.
Data from Glycolytic Phenotype and AMP Kinase Modify the Pathologic Response of Tumor Xenografts to VEGF Neutralization
Authors: Nardo Giorgia , Favaro Elena , Curtarello Matteo , Moserle Lidia , Zulato Elisabetta , Persano Luca , Rossi Elisabetta , Esposito Giovanni , Crescenzi Marika , Casanovas Oriol , Sattler Ulrike , Mueller-Klieser Wolfgang , Biesalski Barbara , Thews Oliver , Canese Rossella , Iorio Egidio , Zanovello Paola , Amadori Alberto , Indraccolo Stefano
Published: March 2024

Abstract
VEGF antagonists are now widely used cancer therapeutics, but predictive biomarkers of response or toxicity remain unavailable. In this study, we analyzed the effects of anti-VEGF therapy on tumor metabolism and therapeutic response by using an integrated set of imaging techniques, including bioluminescence metabolic imaging, 18-fluorodeoxyglucose positron emission tomography, and MRI imaging and spectroscopy. Our results revealed that anti-VEGF therapy caused a dramatic depletion of glucose and an exhaustion of ATP levels in tumors, although glucose uptake was maintained. These metabolic changes selectively accompanied the presence of large necrotic areas and partial tumor regression in highly glycolytic tumors. In addition, we found that the central metabolic protein kinase AMP-activated protein kinase (AMPK)—a cellular sensor of ATP levels that supports cell viability in response to energy stress—was activated by anti-VEGF therapy in experimental tumors. AMPK-α2 attenuation increased glucose consumption, tumor cell sensitivity to glucose starvation, and tumor necrosis following anti-VEGF therapy. Taken together, our findings reveal functional links between the Warburg effect and the AMPK pathway with therapeutic responses to VEGF neutralization in tumor xenograft models. Cancer Res; 71(12); 4214–25. ©2011 AACR.
Data from The ICOS/ICOSL Pathway Is Required for Optimal Antitumor Responses Mediated by Anti–CTLA-4 Therapy
Authors: Fu Tihui , He Qiuming , Sharma Padmanee
Published: March 2024

Abstract
The anti–CTL-associated antigen 4 (anti–CTLA-4) antibody ipilimumab is the first agent to show improved survival in a randomized phase III trial that enrolled patients with metastatic melanoma. Studies are ongoing to identify mechanisms that elicit clinical benefit in the setting of anti–CTLA-4 therapy. We previously reported that treated patients had an increase in the frequency of T cells expressing the inducible costimulator (ICOS) molecule, a T-cell–specific molecule that belongs to the CD28/CTLA-4/B7 immunoglobulin superfamily. ICOS and its ligand (ICOSL) have been shown to play diverse roles in T-cell responses such as mediating autoimmunity as well as enhancing the development/activity of regulatory T cells. These seemingly opposing roles have made it difficult to determine whether the ICOS/ICOSL pathway is necessary for antitumor responses. To determine whether the ICOS/ICOSL pathway might play a causal role in the antitumor effects mediated by anti–CTLA-4, we conducted studies in ICOS-sufficient and ICOS-deficient mice bearing B16/BL6 melanoma. We show that ICOS+ T cells comprised a population of Th1 cytokine producing and tumor antigen-specific effector cells. Furthermore, in the absence of ICOS, antitumor T-cell responses elicited by anti–CTLA-4 are significantly diminished, thereby impairing tumor rejection. Our findings establish that the ICOS/ICOSL pathway is necessary for the optimal therapeutic effect of anti–CTLA-4, thus implicating this pathway as a target for future combinatorial strategies to improve the efficacy of anti–CTLA-4 therapy. Cancer Res; 71(16); 5445–54. ©2011 AACR.
Data from MEK1/2 Inhibitors AS703026 and AZD6244 May Be Potential Therapies for KRAS Mutated Colorectal Cancer That Is Resistant to EGFR Monoclonal Antibody Therapy
Authors: Yoon Juyong , Koo Kyoung-Hwa , Choi Kang-Yell
Published: March 2024

Abstract
Epidermal growth factor receptor (EGFR) monoclonal antibodies (mAb) are used widely to treat metastatic colorectal cancer (mCRC) patients, but it is now clear that patients harboring K-ras mutation are resistant to EGFR mAbs such as cetuximab (Erbitux) and panitumumab (Vectibix). For this reason, current recommendations for patient care involve diagnosing the K-ras mutational status of patients prior to EGFR mAb therapy. In this study, we investigated the ability of two MEK inhibitors currently in clinical trials, AS703026 and AZD6244, to address the challenge posed by the resistance of K-ras mutated colorectal cancers to EGFR mAb. AS703026 and AZD6244 were tested in various cell-based assays and tumor xenograft studies, focusing on isogenic human colorectal tumor cell lines that expressed only WT or mutant K-Ras (D-WT or D-MUT). The EGFR mAb cetuximab inhibited the Ras-ERK pathway and proliferation of D-WT cells in vitro and in vivo, but it did not inhibit proliferation of D-MUT cells in either setting. In contrast, AS703026 and AZD6244 effectively inhibited the growth of D-MUT cells in vitro and in vivo by specific inhibition of the key MEK downstream target kinase ERK. Inhibition of MEK by AS703026 or AZD6244 also suppressed cetuximab-resistant colorectal cancer cells attributed to K-ras mutation both in vitro and in vivo. Our findings offer proof-of-concept for the use of MEK inhibitors as an effective therapy in K-ras mutated CRC. Cancer Res; 71(2); 445–53. ©2010 AACR.
Data from Poly(ADP-Ribose) Polymerase Inhibition Synergizes with 5-Fluorodeoxyuridine but not 5-Fluorouracil in Ovarian Cancer Cells
Authors: Huehls Amelia M. , Wagner Jill M. , Huntoon Catherine J. , Geng Liyi , Erlichman Charles , Patel Anand G. , Kaufmann Scott H. , Karnitz Larry M.
Published: March 2024

Abstract
5-Fluorouracil (5-FU) and 5-fluorodeoxyuridine (FdUrd, floxuridine) have activity in multiple tumors, and both agents undergo intracellular processing to active metabolites that disrupt RNA and DNA metabolism. These agents cause imbalances in deoxynucleotide triphosphate levels and the accumulation of uracil and 5-FU in the genome, events that activate the ATR- and ATM-dependent checkpoint signaling pathways and the base excision repair (BER) pathway. Here, we assessed which DNA damage response and repair processes influence 5-FU and FdUrd toxicity in ovarian cancer cells. These studies revealed that disabling the ATM, ATR, or BER pathways using small inhibitory RNAs did not affect 5-FU cytotoxicity. In stark contrast, ATR and a functional BER pathway protected FdUrd-treated cells. Consistent with a role for the BER pathway, the poly(ADP-ribose) polymerase (PARP) inhibitors ABT-888 (veliparib) and AZD2281 (olaparib) markedly synergized with FdUrd but not with 5-FU in ovarian cancer cell lines. Furthermore, ABT-888 synergized with FdUrd far more effectively than other agents commonly used to treat ovarian cancer. These findings underscore differences in the cytotoxic mechanisms of 5-FU and FdUrd and suggest that combining FdUrd and PARP inhibitors may be an innovative therapeutic strategy for ovarian tumors. Cancer Res; 71(14); 4944–54. ©2011 AACR.
Data from BMP4 Promotes Prostate Tumor Growth in Bone through Osteogenesis
Authors: Lee Yu-Chen , Cheng Chien-Jui , Bilen Mehmet A. , Lu Jing-Fang , Satcher Robert L. , Yu-Lee Li-Yuan , Gallick Gary E. , Maity Sankar N. , Lin Sue-Hwa
Published: March 2024

Abstract
Induction of new bone formation is frequently seen in the bone lesions from prostate cancer. However, whether osteogenesis is necessary for prostate tumor growth in bone is unknown. Recently, 2 xenografts, MDA-PCa-118b and MDA-PCa-133, were generated from prostate cancer bone metastases. When implanted subcutaneously in severe combined immunodeficient (SCID) mice, MDA-PCa-118b induced strong ectopic bone formation while MDA-PCa-133 did not. To identify the factors that are involved in bone formation, we compared the expression of secreted factors (secretome) from MDA-PCa-118b and MDA-PCa-133 by cytokine array. We found that the osteogenic MDA-PCa-118b xenograft expressed higher levels of bone morphogenetic protein BMP4 and several cytokines including interleukin-8, growth-related protein (GRO), and CCL2. We showed that BMP4 secreted from MDA-PCa-118b contributed to about a third of the osteogenic differentiation seen in MDA-PCa-118b tumors. The conditioned media from MDA-PCa-118b induced a higher level of osteoblast differentiation, which was significantly reduced by treatment with BMP4 neutralizing antibody or the small molecule BMP receptor 1 inhibitor LDN-193189. BMP4 did not elicit an autocrine effect on MDA-PCa-118b, which expressed low to undetectable levels of BMP receptors. Treatment of SCID mice bearing MDA-PCa-118b tumors with LDN-193189 significantly reduced tumor growth. Thus, these studies support a role of BMP4-mediated osteogenesis in the progression of prostate cancer in bone. Cancer Res; 71(15); 5194–203. ©2011 AACR.
Data from In Vivo Persistence, Tumor Localization, and Antitumor Activity of CAR-Engineered T Cells Is Enhanced by Costimulatory Signaling through CD137 (4-1BB)
Authors: Song De-Gang , Ye Qunrui , Carpenito Carmine , Poussin Mathilde , Wang Li-Ping , Ji Chunyan , Figini Mariangela , June Carl H. , Coukos George , Powell Daniel J.
Published: March 2024

Abstract
Human T cells engineered to express a chimeric antigen receptor (CAR) specific for folate receptor-α (FRα) have shown robust antitumor activity against epithelial cancers in vitro but not in the clinic because of their inability to persist and home to tumor in vivo. In this study, CARs were constructed containing a FRα-specific scFv (MOv19) coupled to the T-cell receptor CD3ζ chain signaling module alone (MOv19-ζ) or in combination with the CD137 (4-1BB) costimulatory motif in tandem (MOv19-BBζ). Primary human T cells transduced to express conventional MOv19-ζ or costimulated MOv19-BBζ CARs secreted various proinflammatory cytokines, and exerted cytotoxic function when cocultured with FRα+ tumor cells in vitro. However, only transfer of human T cells expressing the costimulated MOv19-BBζ CAR mediated tumor regression in immunodeficient mice bearing large, established FRα+ human cancer. MOv19-BBζ CAR T-cell infusion mediated tumor regression in models of metastatic intraperitoneal, subcutaneous, and lung-involved human ovarian cancer. Importantly, tumor response was associated with the selective survival and tumor localization of human T cells in vivo and was only observed in mice receiving costimulated MOv19-BBζ CAR T cells. T-cell persistence and antitumor activity were primarily antigen-driven; however, antigen-independent CD137 signaling by CAR improved T-cell persistence but not antitumor activity in vivo. Our results show that anti-FRα CAR outfitted with CD137 costimulatory signaling in tandem overcome issues of T-cell persistence and tumor localization that limit the conventional FRα T-cell targeting strategy to provide potent antitumor activity in vivo. Cancer Res; 71(13); 4617–27. ©2011 AACR.
Data from Targeted Therapeutic Remodeling of the Tumor Microenvironment Improves an HER-2 DNA Vaccine and Prevents Recurrence in a Murine Breast Cancer Model
Authors: Liao Debbie , Liu Ze , Wrasidlo Wolfgang J. , Luo Yunping , Nguyen Giang , Chen Tingmei , Xiang Rong , Reisfeld Ralph A.
Published: March 2024

Abstract
The tumor microenvironment (TME) mediates immunosuppression resulting in tumor cell escape from immune surveillance and cancer vaccine failure. Immunosuppression is mediated by the STAT-3 transcription factor, which potentiates signaling in tumor and immune cells. Because immunosuppression continues to be a major inhibitor of cancer vaccine efficacy, we examined in this study whether therapeutically targeted delivery of a synthetic STAT-3 inhibitor to the TME, combined with an HER-2 DNA vaccine can improve immune surveillance against HER-2+ breast cancer and prevent its recurrence. To this end, we developed a novel ligand-targeted nanoparticle (NP) encapsulating a CDDO-Im payload capable of specific delivery to the TME, which showed an effective therapeutic inhibition of STAT-3 activation in primary tumors. Furthermore, we showed that treatment with these NPs resulted in priming of the immune TME, characterized by increased IFN-γ, p-STAT-1, GM-CSF, IL-2, IL-15, and IL-12b and reduced TGF-β, IL-6, and IL-10 protein expression. In addition, we found significantly increased tumor infiltration by activated CD8+ T cells, M1 macrophages, and dendritic cells. These changes correlated with delayed growth of orthotopic 4TO7 breast tumors and, when combined with an HER-2 DNA vaccine, prevented HER-2+ primary tumor recurrence in immunocompetent mice. Furthermore, antitumor T-cell responses were enhanced in splenocytes isolated from mice treated with this combination therapy. Together, these data show effective protection from cancer recurrence through improved immune surveillance against a tumor-specific antigen. Cancer Res; 71(17); 5688–96. ©2011 AACR.
Data from CaM Kinase Kinase β-Mediated Activation of the Growth Regulatory Kinase AMPK Is Required for Androgen-Dependent Migration of Prostate Cancer Cells
Authors: Frigo Daniel E. , Howe Matthew K. , Wittmann Bryan M. , Brunner Abigail M. , Cushman Ian , Wang Qianben , Brown Myles , Means Anthony R. , McDonnell Donald P.
Published: March 2024

Abstract
While patients with advanced prostate cancer initially respond favorably to androgen ablation therapy, most experience a relapse of the disease within 1–2 years. Although hormone-refractory disease is unresponsive to androgen-deprivation, androgen receptor (AR)-regulated signaling pathways remain active and are necessary for cancer progression. Thus, both AR itself and the processes downstream of the receptor remain viable targets for therapeutic intervention. Microarray analysis of multiple clinical cohorts showed that the serine/threonine kinase Ca2+/calmodulin-dependent protein kinase kinase β (CaMKKβ) is both highly expressed in the prostate and further elevated in prostate cancers. Using cellular models of prostate cancer, we have determined that androgens (a) directly increase the expression of a CaMKKβ splice variant and (b) increase functional CaMKKβ protein levels as determined by the phosphorylation of both CaMKI and AMP-activated protein kinase (AMPK), two of CaMKKβ's primary substrates. Importantly, inhibition of the CaMKKβ-AMPK, but not CaMKI, signaling axis in prostate cancer cells by pharmacological inhibitors or siRNA-mediated knockdown blocks androgen-mediated migration and invasion. Conversely, overexpression of CaMKKβ alone leads to both increased AMPK phosphorylation and cell migration. Given the key roles of CaMKKβ and AMPK in the biology of prostate cancer cells, we propose that these enzymes are potential therapeutic targets in prostate cancer. Cancer Res; 71(2); 528–37. ©2010 AACR.
Data from Potent Antitumor Immunity Generated by a CD40-Targeted Adenoviral Vaccine
Authors: Hangalapura Basav N. , Oosterhoff Dinja , de Groot Jan , Boon Louis , Tüting Thomas , van den Eertwegh Alfons J. , Gerritsen Winald R. , van Beusechem Victor W. , Pereboev Alexander , Curiel David T. , Scheper Rik J. , de Gruijl Tanja D.
Published: March 2024

Abstract
In situ delivery of tumor-associated antigen (TAA) genes into dendritic cells (DC) has great potential as a generally applicable tumor vaccination approach. Although adenoviruses (Ad) are an attractive vaccine vehicle in this regard, Ad-mediated transduction of DCs is hampered by the lack of expression of the Ad receptor CAR on the DC surface. DC activation also requires interaction of CD40 with its ligand CD40L to generate protective T-cell–mediated tumor immunity. Therefore, to create a strategy to target Ads to DCs in vivo, we constructed a bispecific adaptor molecule with the CAR ectodomain linked to the CD40L extracellular domain via a trimerization motif (CFm40L). By targeting Ad to CD40 with the use of CFm40L, we enhanced both transduction and maturation of cultured bone marrow–derived DCs. Moreover, we improved transduction efficiency of DCs in lymph node and splenic cell suspensions in vitro and in skin and vaccination site–draining lymph nodes in vivo. Furthermore, CD40 targeting improved the induction of specific CD8+ T cells along with therapeutic efficacy in a mouse model of melanoma. Taken together, our findings support the use of CD40-targeted Ad vectors encoding full-length TAA for in vivo targeting of DCs and high-efficacy induction of antitumor immunity. Cancer Res; 71(17); 5827–37. ©2011 AACR.
Data from Coexpression of Oct4 and Nanog Enhances Malignancy in Lung Adenocarcinoma by Inducing Cancer Stem Cell–Like Properties and Epithelial–Mesenchymal Transdifferentiation
Authors: Chiou Shih-Hwa , Wang Mong-Lien , Chou Yu-Ting , Chen Chi-Jen , Hong Chun-Fu , Hsieh Wang-Ju , Chang Hsin-Tzu , Chen Ying-Shan , Lin Tzu-Wei , Hsu Han-Sui , Wu Cheng-Wen
Published: March 2024

Abstract
Epithelial–mesenchymal transition (EMT), a critical process of cancer invasion and metastasis, is associated with stemness property of cancer cells. Though Oct4 and Nanog are homebox transcription factors essential to the self-renewal of stem cells and are expressed in several cancers, the role of Oct4/Nanog signaling in tumorigenesis is still elusive. Here microarray and quantitative real-time PCR analysis showed a parallel, elevated expression of Oct4 and Nanog in lung adenocarcinoma (LAC). Ectopic expressions of Oct4 and Nanog in LACs increased the percentage of CD133-expressing subpopulation and sphere formation, enhanced drug resistance, and promoted EMT. Ectopic expressions of Oct4 and Nanog activated Slug and enhanced the tumor-initiating capability of LAC. Furthermore, double knockdown of Oct4 and Nanog suppressed the expression of Slug, reversed the EMT process, blocked the tumorigenic and metastatic ability, and greatly improved the mean survival time of transplanted immunocompromised mice. The immunohistochemical analysis demonstrated that expressions of Oct4, Nanog, and Slug were present in high-grade LAC, and triple positivity of Oct4/Nanog/Slug indicated a worse prognostic value of LAC patients. Our results support the notion that the Oct4/Nanog signaling controls epithelial–mesenchymal transdifferentiation, regulates tumor-initiating ability, and promotes metastasis of LAC. Cancer Res; 70(24); 10433–44. ©2010 AACR.
Data from Myeloid-Derived Suppressor Cell Inhibition of the IFN Response in Tumor-Bearing Mice
Authors: Mundy-Bosse Bethany L. , Lesinski Gregory B. , Jaime-Ramirez Alena C. , Benninger Kristen , Khan Mahmood , Kuppusamy Periannan , Guenterberg Kristan , Kondadasula Sri Vidya , Chaudhury Abhik Ray , La Perle Krista M. , Kreiner Melanie , Young Gregory , Guttridge Denis C. , Carson William E.
Published: March 2024

Abstract
Our group and others have determined that immune effector cells from patients with advanced cancers exhibit reduced activation of IFN signaling pathways. We hypothesized that increases in immune regulatory cells termed myeloid-derived suppressor cells (MDSC) could interfere with the host immune response to tumors by inhibiting immune cell responsiveness to IFNs. The C26 murine adenocarcinoma model was employed to study immune function in advanced malignancy. C26-bearing mice had significantly elevated levels of GR1+CD11b+ MDSC as compared with control mice, and splenocytes from tumor-bearing mice exhibited reduced phosphorylation of STAT1 (P-STAT1) on Tyr701 in response to IFN-α or IFN-γ. This inhibition was seen in splenic CD4+ and CD8+ T cells as well as natural killer cells. In vitro coculture experiments revealed that MDSC inhibited the IFN responsiveness of splenocytes from normal mice. Treatment of C26-bearing mice with gemcitabine or an anti-GR1 antibody led to depletion of MDSC and restored splenocyte IFN responsiveness. Spleens from C26-bearing animals displayed elevated levels of iNOS protein and nitric oxide. In vitro treatment of splenocytes with a nitric oxide donor led to a decreased STAT1 IFN response. The elevation in nitric oxide in C26-bearing mice was associated with increased levels of nitration on STAT1. Finally, splenocytes from iNOS knockout mice bearing C26 tumors exhibited a significantly elevated IFN response as compared with control C26 tumor-bearing mice. These data suggest that nitric oxide produced by MDSC can lead to reduced IFN responsiveness in immune cells. Cancer Res; 71(15); 5101–10. ©2011 AACR.
Data from Using Tandem Mass Spectrometry in Targeted Mode to Identify Activators of Class IA PI3K in Cancer
Authors: Yang Xuemei , Turke Alexa B. , Qi Jie , Song Youngchul , Rexer Brent N. , Miller Todd W. , Jänne Pasi A. , Arteaga Carlos L. , Cantley Lewis C. , Engelman Jeffrey A. , Asara John M.
Published: March 2024

Abstract
Phosphatiditylinositide-3-kinase (PI3K) is activated in some cancers by direct mutation, but it is activated more commonly in cancer by mutation of upstream acting receptor tyrosine kinases (TK). At present, there is no systematic method to determine which TK signaling cascades activate PI3K in certain cancers, despite the likely utility of such information to help guide selection of tyrosine kinase inhibitor (TKI) drug strategies for personalized therapy. Here, we present a quantitative liquid chromatography tandem mass spectrometry approach that identifies upstream activators of PI3K both in vitro and in vivo. Using non–small cell lung carcinoma to illustrate this approach, we show a correct identification of the mechanism of PI3K activation in several models, thereby identifying the most appropriate TKI to downregulate PI3K signaling. This approach also determined the molecular mechanisms and adaptors required for PI3K activation following inhibition of the mTOR kinase TORC1. We further validated the approach in breast cancer cells with mutational activation of PIK3CA, where tandem mass spectrometry detected and quantitatively measured the abundance of a helical domain mutant (E545K) of PIK3CA connected to PI3K activation. Overall, our findings establish a mass spectrometric approach to identify functional interactions that govern PI3K regulation in cancer cells. Using this technique to define the pathways that activate PI3K signaling in a given tumor could help inform clinical decision making by helping guide personalized therapeutic strategies for different patients. Cancer Res; 71(18); 5965–75. ©2011 AACR.
Data from PD-1/PD-L1 Interactions Contribute to Functional T-Cell Impairment in Patients Who Relapse with Cancer After Allogeneic Stem Cell Transplantation
Authors: Norde Wieger J. , Maas Frans , Hobo Willemijn , Korman Alan , Quigley Michael , Kester Michel G.D. , Hebeda Konnie , Falkenburg J.H. Frederik , Schaap Nicolaas , de Witte Theo M. , van der Voort Robbert , Dolstra Harry
Published: March 2024

Abstract
Tumor relapses remain a serious problem after allogeneic stem cell transplantation (alloSCT), despite the long-term persistence of minor histocompatibility antigen (MiHA)-specific memory CD8+ T cells specific for the tumor. We hypothesized that these memory T cells may lose their function over time in transplanted patients. Here, we offer functional and mechanistic support for this hypothesis, based on immune inhibition by programmed death-1 (PD-1) expressed on MiHA-specific CD8+ T cells and the associated role of the PD-1 ligand PD-L1 on myeloid leukemia cells, especially under inflammatory conditions. PD-L1 was highly upregulated on immature human leukemic progenitor cells, whereas costimulatory molecules such as CD80 and CD86 were not expressed. Thus, immature leukemic progenitor cells seemed to evade the immune system by inhibiting T-cell function via the PD-1/PD-L1 pathway. Blocking PD-1 signaling using human antibodies led to elevated proliferation and IFN-γ production of MiHA-specific T cells cocultured with PD-L1–expressing leukemia cells. Moreover, patients with relapsed leukemia after initial MiHA-specific T-cell responses displayed high PD-L1 expression on CD34+ leukemia cells and increased PD-1 levels on MiHA-specific CD8+ T cells. Importantly, blocking PD-1/PD-L1 interactions augment proliferation of MiHA-specific CD8+ memory T cells from relapsed patients. Taken together, our findings indicate that the PD-1/PD-L pathway can be hijacked as an immune escape mechanism in hematological malignancies. Furthermore, they suggest that blocking the PD-1 immune checkpoint offers an appealing immunotherapeutic strategy following alloSCT in patients with recurrent or relapsed disease. Cancer Res; 71(15); 5111–22. ©2011 AACR.
Data from Aurora A Is a Repressed Effector Target of the Chromatin Remodeling Protein INI1/hSNF5 Required for Rhabdoid Tumor Cell Survival
Authors: Lee SeungJae , Cimica Velasco , Ramachandra Nandini , Zagzag David , Kalpana Ganjam V.
Published: March 2024

Abstract
Rhabdoid tumors (RT) are aggressive pediatric malignancies with poor prognosis. INI1/hSNF5 is a component of the chromatin remodeling SWI/SNF complex and a tumor suppressor deleted in RT. Previous microarray studies indicated that reintroduction of INI1/hSNF5 into RT cells leads to repression of a high degree of mitotic genes including Aurora Kinase A (Aurora A, STK6). Here, we found that INI1/SNF5 represses Aurora A transcription in a cell-type–specific manner. INI1-mediated repression was observed in RT and normal cells but not in non-RT cell lines. Chromatin immunoprecipitation (ChIP) assay indicated that INI1/hSNF5 associates with Aurora A promoter in RT and normal cells but not in non-RT cells. Real-time PCR and immunohistochemical analyses of primary human and mouse RTs harboring mutations in INI1/hSNF5 gene indicated that Aurora A was overexpressed/derepressed in these tumor cells, confirming that INI1/hSNF5 represses Aurora A in vivo. Knockdown of Aurora A impaired cell growth, induced mitotic arrest and aberrant nuclear division leading to decreased survival, and increased cell death and caspase 3/7-mediated apoptosis in RT cells (but not in normal cells). These results indicated that Aurora A is a direct downstream target of INI1/hSNF5-mediated repression in RT cells and that loss of INI1/hSNF5 leads to aberrant overexpression of Aurora A in these tumors, which is required for their survival. We propose that a high degree of Aurora A expression may play a role in aggressive behavior of RTs and that targeting expression or activity of this gene is a novel therapeutic strategy for these tumors. Cancer Res; 71(9); 3225–35. ©2011 AACR.
Data from Increased Efficacy of Breast Cancer Chemotherapy in Thrombocytopenic Mice
Authors: Demers Mélanie , Ho-Tin-Noé Benoit , Schatzberg Daphne , Yang Janie J. , Wagner Denisa D.
Published: March 2024

Abstract
Platelets contribute to homeostasis of the tumor vasculature by helping prevent hemorrhage. Thus, we hypothesized that inducing thrombocytopenia would increase tumor vascular leakiness and facilitate the effective delivery of chemotherapeutic agents to tumors. In a mammary carcinoma murine model, platelet depletion induced bleeding specifically at the tumor site, favoring the accumulation of fluorescently labeled microspheres only in the tumor. Moreover, induction of thrombocytopenia in tumor-bearing mice before injection of paclitaxel increased its intratumoral accumulation and reduced growth of both slow- and fast-growing tumors, compared with mice with normal platelet counts that were treated only with paclitaxel. Histologic analysis confirmed the expectation of an increase in tumor apoptosis and a reduction in tumor proliferation in thrombocytopenic mice receiving chemotherapy. No increased toxicity was seen in other organs or blood cells. Taken together, our results indicate that low platelet count selectively induces leakiness of tumor vessels and favors the delivery of chemotherapy to tumor sites, enhancing its tumoricidal effects. Cancer Res; 71(5); 1540–9. ©2011 AACR.
Data from Vitamin D3 Enhances the Apoptotic Response of Epithelial Tumors to Aminolevulinate-Based Photodynamic Therapy
Authors: Anand Sanjay , Wilson Clara , Hasan Tayyaba , Maytin Edward V.
Published: March 2024

Abstract
Photodynamic therapy, mediated by exogenously administered aminolevulinic acid (ALA-PDT), followed by exposure to a laser or broadband light source, is a promising modality for treatment of many types of cancers; however, it remains inadequate to treat large, deep, solid tumors. In this article, we report that calcitriol, the active form of vitamin D3, can be administered before ALA as a nontoxic preconditioning regimen to markedly increase the efficacy of ALA-PDT. Using mouse models of squamous cell skin cancer for preclinical proof of concept, we showed that calcitriol, delivered topically or intraperitoneally, increased tumoral accumulation of the PDT-activated ALA product protoporphyrin-IX (PpIX) up to 10-fold, mainly by altering expression of the porphyrin-synthesis enzymes coproporphyrinogen oxidase (increased) and ferrochelatase (decreased). Calcitriol-pretreated tumors underwent enhanced apoptotic cell death after ALA-based PDT. Mechanistic studies have documented activation of the extrinsic apoptotic pathway, with specific cleavage of caspase-8 and increased production of TNF-α in tumors preconditioned by calcitriol treatment before receiving ALA-PDT. Very low doses of calcitriol (0.1–1 μg/kg body weight) were sufficient to elicit tumor-selective enhancement to ALA-PDT efficacy, rendering toxicity concerns negligible. Our findings define a simple, nontoxic, and highly effective preconditioning regimen to enhance the response of epithelial tumors to ALA-PDT, possibly broadening its clinical applications by selectively enhancing accumulation of photosensitizer PpIX together with TNF-α in tumors. Cancer Res; 71(18); 6040–50. ©2011 AACR.
Data from Convection-Enhanced Delivery of Topotecan into a PDGF-Driven Model of Glioblastoma Prolongs Survival and Ablates Both Tumor-Initiating Cells and Recruited Glial Progenitors
Authors: Lopez Kim A. , Tannenbaum Aaron M. , Assanah Marcela C. , Linskey Katy , Yun Jonathan , Kangarlu Alayar , Gil Orlando D. , Canoll Peter , Bruce Jeffrey N.
Published: March 2024

Abstract
The contribution of microenvironment to tumor growth has important implications for optimizing chemotherapeutic response and understanding the biology of recurrent tumors. In this study, we tested the effects of locally administered topotecan on a rat model of glioblastoma that is induced by intracerebral injection of PDGF (platelet-derived growth factor)-IRES (internal ribosome entry site)-GFP (green fluorescent protein)–expressing retrovirus, treated the tumors by convection-enhanced delivery (CED) of topotecan (136 μmol/L) for 1, 4, or 7 days, and then characterized the effects on both the retrovirus-transformed tumor cells (GFP+ cells) as well as the uninfected glial progenitor cells (GFP− cells) that are recruited to the tumor. Topotecan treatment reduced GFP+ cells about 10-fold and recruited progenitors by about 80-fold while providing a significant survival advantage that improved with greater treatment duration. Regions of glial progenitor ablation occurred corresponding to the anatomic distribution of topotecan as predicted by MRI of a surrogate tracer. Histopathologic changes in recurrent tumors point to a decrease in recruitment, most likely due to the chemotherapeutic ablation of the recruitable progenitor pool. Cancer Res; 71(11); 3963–71. ©2011 AACR.
Data from Coexpression Network Analysis Identifies Transcriptional Modules Related to Proastrocytic Differentiation and Sprouty Signaling in Glioma
Authors: Ivliev Alexander E. , 't Hoen Peter A.C. , Sergeeva Marina G.
Published: March 2024

Abstract
Gliomas are primary brain tumors with high mortality and heterogeneous biology that is insufficiently understood. In this study, we performed a systematic analysis of the intrinsic organization of complex glioma transcriptome to gain deeper knowledge of the tumor biology. Gene coexpression relationships were explored in 790 glioma samples from 5 published patient cohorts treated at different institutions. We identified 20 coexpression modules that were common to all the data sets and associated with proliferation, angiogenesis, hypoxia, immune response, genomic alterations, cell differentiation phenotypes, and other features inherent to glial tumors. A collection of high-quality signatures for the respective processes was obtained using cross‐data set summarization of the modules' gene composition. Individual modules were found to be organized into higher order coexpression groups, the two largest of them associated with glioblastoma and oligodendroglioma, respectively. We identified a novel prognostic gene expression signature (185 genes) linked to a proastrocytic pattern of tumor cell differentiation. This “proastrocytic” signature was associated with long survival and defined a subgroup of the previously established “proneural” class of gliomas. A strong negative correlation between proastrocytic and proneural markers across differentiated tumors underscored the distinction between these subtypes of glioma. Interestingly, one further novel signature in glioma was identified that was associated with EGFR (epidermal growth factor receptor) gene amplification and suggested that EGF signaling in glioma may be a subject to regulation by Sprouty family proteins. In summary, this integrated analysis of the glioma transcriptome provided several novel insights into molecular heterogeneity and pathogenesis of glial tumors. Cancer Res; 70(24); 10060–70. ©2010 AACR.
Data from A Novel Tumor Antigen Derived from Enhanced Degradation of Bax Protein in Human Cancers
Authors: Nunes Cláudia Trindade , Miners Kelly L. , Dolton Garry , Pepper Chris , Fegan Chris , Mason Malcolm D. , Man Stephen
Published: March 2024

Abstract
Cancer cells frequently exhibit defects in apoptosis, which contribute to increased survival and chemotherapeutic resistance. For example, genetic mutations or abnormal proteasomal degradation can reduce expression of Bax which limits apoptosis. In cancers where abnormal proteasomal degradation of Bax occurs, we hypothesized that Bax peptides that bind to human leukocyte antigen (HLA) class I molecules would be generated for presentation to CD8+ T cells. To test this hypothesis, we generated T cells against pooled Bax peptides, using the blood of healthy human donors. Although T-cell responses were of low frequency (0.15%), a CD8+ T-cell clone (KSIVB17) was isolated that optimally recognized Bax136–144 peptide (IMGWTLDFL) presented by HLA-A*0201. KSIVB17 was able to recognize and kill a variety of HLA-matched cancer cells including primary tumor cells from chronic lymphocytic leukemia (CLL). No reactivity was seen against HLA-matched, nontransformed cells such as PHA blasts and skin fibroblasts. Furthermore, KSIVB17 reactivity corresponded with the proteasomal degradation patterns of Bax protein observed in cancer cells. Taken together, our findings suggest a new concept for tumor antigens based on regulatory proteins that are ubiquitously expressed in normal cells, but that have abnormally enhanced degradation in cancer cells. Bax degradation products offer candidate immune antigens in cancers such as CLL in which increased Bax degradation correlates with poor clinical prognosis. Cancer Res; 71(16); 5435–44. ©2011 AACR.
Data from Splicing Factor hnRNP A2/B1 Regulates Tumor Suppressor Gene Splicing and Is an Oncogenic Driver in Glioblastoma
Authors: Golan-Gerstl Regina , Cohen Michal , Shilo Asaf , Suh Sung-Suk , Bakàcs Arianna , Coppola Luigi , Karni Rotem
Published: March 2024

Abstract
The process of alternative splicing is widely misregulated in cancer, but the contribution of splicing regulators to cancer development is largely unknown. In this study, we found that the splicing factor hnRNP A2/B1 is overexpressed in glioblastomas and is correlated with poor prognosis. Conversely, patients who harbor deletions of the HNRNPA2B1 gene show better prognosis than average. Knockdown of hnRNP A2/B1 in glioblastoma cells inhibited tumor formation in mice. In contrast, overexpression of hnRNP A2/B1 in immortal cells led to malignant transformation, suggesting that HNRNPA2B1 is a putative proto-oncogene. We then identified several tumor suppressors and oncogenes that are regulated by HNRNPA2B1, among them are c-FLIP, BIN1, and WWOX, and the proto-oncogene RON. Knockdown of RON inhibited hnRNP A2/B1 mediated transformation, which implied that RON is one of the mediators of HNRNPA2B1 oncogenic activity. Together, our results indicate that HNRNPA2B1 is a novel oncogene in glioblastoma and a potential new target for glioblastoma therapy. Cancer Res; 71(13); 4464–72. ©2011 AACR.
Data from IL-18 Induces PD-1–Dependent Immunosuppression in Cancer
Authors: Terme Magali , Ullrich Evelyn , Aymeric Laetitia , Meinhardt Kathrin , Desbois Mélanie , Delahaye Nicolas , Viaud Sophie , Ryffel Bernard , Yagita Hideo , Kaplanski Gilles , Prévost-Blondel Armelle , Kato Masashi , Schultze Joachim L. , Tartour Eric , Kroemer Guido , Chaput Nathalie , Zitvogel Laurence
Published: March 2024

Abstract
Immunosuppressive cytokines subvert innate and adaptive immune responses during cancer progression. The inflammatory cytokine interleukin-18 (IL-18) is known to accumulate in cancer patients, but its pathophysiological role remains unclear. In this study, we show that low levels of circulating IL-18, either exogenous or tumor derived, act to suppress the NK cell arm of tumor immunosurveillance. IL-18 produced by tumor cells promotes the development of NK-controlled metastases in a PD-1–dependent manner. Accordingly, PD-1 is expressed by activated mature NK cells in lymphoid organs of tumor bearers and is upregulated by IL-18. RNAi-mediated knockdown of IL-18 in tumors, or its systemic depletion by IL-18–binding protein, are sufficient to stimulate NK cell-dependent immunosurveillance in various tumor models. Together, these results define IL-18 as an immunosuppressive cytokine in cancer. Our findings suggest novel clinical implementations of anti-PD-1 antibodies in human malignancies that produce IL-18. Cancer Res; 71(16); 5393–9. ©2011 AACR.
Data from Combining ATR Suppression with Oncogenic Ras Synergistically Increases Genomic Instability, Causing Synthetic Lethality or Tumorigenesis in a Dosage-Dependent Manner
Authors: Gilad Oren , Nabet Barzin Y. , Ragland Ryan L. , Schoppy David W. , Smith Kevin D. , Durham Amy C. , Brown Eric J.
Published: March 2024

Abstract
Previous studies indicate that oncogenic stress activates the ATR-Chk1 pathway. Here, we show that ATR-Chk1 pathway engagement is essential for limiting genomic instability following oncogenic Ras transformation. ATR pathway inhibition in combination with oncogenic Ras expression synergistically increased genomic instability, as quantified by chromatid breaks, sister chromatid exchanges, and H2AX phosphorylation. This level of instability was significantly greater than that observed following ATR suppression in untransformed control cells. In addition, consistent with a deficiency in long-term genome maintenance, hypomorphic ATR pathway reduction to 16% of normal levels was synthetic lethal with oncogenic Ras expression in cultured cells. Notably, elevated genomic instability and synthetic lethality following suppression of ATR were not due to accelerated cycling rates in Ras-transformed cells, indicating that these synergistic effects were generated on a per-cell-cycle basis. In contrast to the synthetic lethal effects of hypomorphic ATR suppression, subtle reduction of ATR expression (haploinsufficiency) in combination with endogenous levels of K-rasG12D expression elevated the incidence of lung adenocarcinoma, spindle cell sarcoma, and thymic lymphoma in p53 heterozygous mice. K-rasG12D-induced tumorigenesis in ATR+/−p53+/− mice was associated with intrachromosomal deletions and loss of wild-type p53. These findings indicate that synergistic increases in genomic instability following ATR reduction in oncogenic Ras-transformed cells can produce 2 distinct biological outcomes: synthetic lethality upon significant suppression of ATR expression and tumor promotion in the context of ATR haploinsufficiency. These results highlight the importance of the ATR pathway both as a barrier to malignant progression and as a potential target for cancer treatment. Cancer Res; 70(23); 9693–702. ©2010 AACR.