bluuebunny/crossref_metadata_2025_split huggingface dataset:
Clonal Evolution of Resistance to Imatinib in Patients with Metastatic Gastrointestinal Stromal Tumors
Authors: Desai Jayesh , Shankar Sridhar , Heinrich Michael C. , Fletcher Jonathan A. , Fletcher Christopher D. , Manola Judi , Morgan Jeffrey A. , Corless Christopher L. , George Suzanne , Tuncali Kemal , Silverman Stuart G. , Van den Abbeele Annick D. , van Sonnenberg Eric , Demetri George D. 
Published: September 2007

Abstract
Purpose: Resistance to imatinib mesylate is emerging as a clinical challenge in patients with metastatic gastrointestinal stromal tumors (GIST). Novel patterns of progression have been noted in a number of these patients. The objective of this study was to correlate molecular and radiologic patterns of imitinib-refractory disease with existing conventional criteria for disease progression.
Experimental Design: Patients with metastatic GIST treated with imatinib were followed with serial computed tomography/magnetic resonance imaging and [18F]fluoro-2-deoxy-d-glucose positron emission tomography. Where feasible, biopsies were done to document disease progression.
Results: A total of 89 patients were followed for a median of 43 months. Forty-eight patients developed progressive disease. A unique “resistant clonal nodule” pattern (defined as a new enhancing nodular focus enclosed within a preexisting tumor mass) was seen in 23 of 48 patients and was thought to represent emergence of clones resistant to imatinib. Nodules were demonstrable a median of 5 months (range, 0-13 months) before objective progression defined by tumor size criteria and were the first sign of progression in 18 of 23 patients. Median survival among patients whose first progression was nodular was 35.1 months, compared with 44.6 months for patients whose first progression met Southwest Oncology Group criteria (P = 0.31). Comparative tumor biopsies were done in 10 patients at baseline and from progressing nodules. Genotypic analyses of KIT and PDGFRA kinases were done, revealing new activating kinase mutations in 80% (8 of 10) of these patients.
Conclusion: The resistant clonal nodule is a unique pattern of disease progression seen in patients with GISTs after an initial response to imatinib and reflects the emergence of imatinib-resistant clones. Conventional tumor measurements (Southwest Oncology Group/Response Evaluation Criteria in Solid Tumors) do not detect this subtle finding. A new enhancing nodule growing within a preexisting tumor mass should be classified as a new lesion and be regarded, at least, as partial progression of GIST.
Preclinical Analysis of Tasidotin HCl in Ewing's Sarcoma, Rhabdomyosarcoma, Synovial Sarcoma, and Osteosarcoma
Authors: Garg Vaani , Zhang Wendong , Gidwani Pooja , Kim Mimi , Kolb E. Anders 
Published: September 2007

Abstract
Purpose: Dolastatins are a group of structurally unique peptides originally isolated from a sea hare, Dolabella auricularia, which seem to inhibit tubulin polymerization and mitosis. Tasidotin hydrochloride (tasidotin), a novel synthetic analogue of dolastatin 15, is evaluated in preclinical models of pediatric tumors.
Experimental Design: The cytotoxicity of tasidotin was evaluated in a panel of pediatric sarcoma cell lines in vitro and in vivo.
Results: The IC50 in Ewing's sarcoma, rhabdomyosarcoma, osteosarcoma, and synovial sarcoma lines ranged from 0.002 μ to 0.32 μmol/L. In the SK-ES1 and RH30 cell lines, tasidotin induced a G2-M arrest that persisted for 48 h after the drug was washed from the cells. In vitro, more than half the cells were in the early or late phase of apoptosis 48 h after treatment with tasidotin. In vivo, a significant increase in apoptotic nuclei was apparent in xenograft tumors harvested within 24 h after a 5-day course of tasidotin. In vivo response was determined in severe combined immunodeficient xenograft models of pediatric sarcomas implanted heterotopically. Significant antitumor activity was observed in all tumor lines tested. A complete response was observed in 2 synovial sarcoma lines, 1 osteosarcoma line, 1 rhabdomyosarcoma line, and 1 Ewing's sarcoma line. A partial response was observed in 1 rhabdomyosarcoma and 1 Ewing's sarcoma.
Conclusions: Tasidotin induces a G2-M block in treated cells ultimately resulting in apoptosis. Antitumor activity is confirmed in vivo in preclinical xenograft models of pediatric sarcomas.
Pathways Mediating the Expansion and Immunosuppressive Activity of Myeloid-Derived Suppressor Cells and Their Relevance to Cancer Therapy
Authors: Talmadge James E. 
Published: September 2007

AbstractCancer immunotherapy has focused on inducing and expanding CTLs and improving the immune recognition of weak antigenic determinants expressed by tumors. However, few positive clinical outcomes have been reported due, in part, to tumor-associated immunologic tolerance, supporting the need for an emphasis on overcoming immunosuppression. Systemic immunosuppression is associated with abnormal myelopoiesis secondary to tumor growth, myelosuppressive therapy, and growth factor administration and subsequent expansion/mobilization of bone marrow–derived immunosuppressive cells. These myeloid-derived suppressor cells (MDSC) reduce activated T-cell number and inhibit their function by multiple mechanisms, including depletion of l-arginine by arginase-1 (ARG1) production of nitric oxide, reactive oxygen species, and reactive nitrogen oxide species by inducible nitric oxide synthase. Increased numbers of MDSCs are associated with neoplastic, inflammatory, infectious, and graft-versus-host diseases where they restrain exuberant or novel T-cell responses. In this review, we discuss critical components of MDSC-mediated suppression of T-cell function, including cellular expansion and activation-induced secretion of immunosuppressive mediators. Both components of MDSC bioactivity are amenable to pharmacologic intervention as discussed herein. We also focus on the relationship between MDSCs, tumor growth, therapeutic responses, and the mechanisms of cellular expansion, activation, and immunosuppression.
Atorvastatin and Celecoxib Inhibit Prostate PC-3 Tumors in Immunodeficient Mice
Authors: Zheng Xi , Cui Xiao-Xing , Avila Gina E. , Huang Mou-Tuan , Liu Yue , Patel Jagruti , Kong Ah Ng Tony , Paulino Raphael , Shih Weichung Joe , Lin Yong , Rabson Arnold B. , Reddy Bandaru S. , Conney Allan H. 
Published: September 2007

Abstract
Purpose: To investigate the effects and mechanisms of atorvastatin and celecoxib administered individually or in combination on human prostate cancer PC-3 cells cultured in vitro or grown as xenograft tumors in immunodeficient mice.
Experimental Design: Human prostate cancer PC-3 cells in culture were treated with atorvastatin and celecoxib alone or in combination. Severe combined immunodeficient (SCID) mice were injected s.c. with PC-3 cells. The mice received daily i.p injections starting 2 days before tumor cell inoculation and continuing during the course of treatment with atorvastatin (10 μg/g body weight/d), celecoxib (10 μg/g/d), a combination of atorvastatin (10 μg/g/d) and celecoxib (10 μg/g/d), or a combination of atorvastatin (5 μg/g/d) and celecoxib (5 μg/g/d).
Results: Atorvastatin in combination with celecoxib had stronger effects on growth inhibition and apoptosis of PC-3 cells than either agent used individually. Atorvastatin and celecoxib in combination also had a stronger inhibitory effect on activation of nuclear factor-κB and extracellular signal-regulated kinase 1/2 in PC-3 cells than either agent alone. Treatment of SCID mice with combinations of atorvastatin and celecoxib more effectively inhibited the formation and growth of PC-3 tumors in the mice than either agent administered alone.
Conclusions: A combination of atorvastatin and celecoxib had a more potent inhibitory effect on the growth of PC-3 cells cultured in vitro or grown in SCID mice than either agent alone. A combination of atorvastatin and celecoxib may be an effective strategy for the prevention of prostate cancer.
Preoperative Plasma HER2 and Epidermal Growth Factor Receptor for Staging and Prognostication in Patients with Clinically Localized Prostate Cancer
Authors: Shariat Shahrokh F. , Bensalah Karim , Karam Jose A. , Roehrborn Claus G. , Gallina Andrea , Lotan Yair , Slawin Kevin M. , Karakiewicz Pierre I. 
Published: September 2007

Abstract
Purpose: Human epidermal growth factor receptor-2 (HER2) and epidermal growth factor receptor (EGFR) expression have been associated with disease progression in patients with prostate cancer. We tested the hypothesis that plasma levels of HER2 and/or EGFR are associated with prostate cancer stage and prognosis in patients with clinically localized disease.
Experimental Design: We measured preoperative plasma HER2 and EGFR levels using commercially available ELISAs on banked plasma from 227 patients treated with radical prostatectomy and bilateral lymphadenectomy for clinically localized prostate adenocarcinoma.
Results: Median preoperative plasma EGFR and HER2 levels were 31.4 ng/mL (interquartile range, 19.2 ng/mL) and 10.0 ng/mL (interquartile range, 2.7 ng/mL), respectively. HER2 was elevated in patients with seminal vesicle invasion (P = 0.033). In separate multivariate analyses that adjusted for the effects of standard preoperative predictors, lower EGFR, higher HER2, and higher HER2/EGFR ratio were associated with prostate-specific antigen (PSA) progression (P = 0.003, P &lt; 0.001, and P &lt; 0.001, respectively). In separate multivariate analyses that adjusted for the effects of standard postoperative predictors, lower EGFR and higher HER2/EGFR ratio were associated with PSA progression (P = 0.027 and P &lt; 0.001, respectively). Among the patients who experienced PSA progression, HER2 was significantly higher (P = 0.023) and EGFR was lower (P = 0.04) in those with features of aggressive disease (i.e., development of metastasis, PSA doubling time &lt;10 months, and/or failure to respond to local salvage radiation therapy).
Conclusion: Preoperative plasma HER2 and EGFR were associated with prostate cancer progression after radical prostatectomy. Plasma HER2 and EGFR may provide a tool for predicting long-term recurrence-free survival and early metastasis.
Targeting Methylguanine-DNA Methyltransferase in the Treatment of Neuroblastoma
Authors: Wagner Lars M. , McLendon Roger E. , Yoon K. Jin , Weiss Brian D. , Billups Catherine A. , Danks Mary K. 
Published: September 2007

AbstractPurpose: The combination of temozolomide and irinotecan has preclinical schedule-dependent synergy against neuroblastoma but is not curative for relapsed high-risk patients. We hypothesized that the DNA repair protein methylguanine-DNA methyltransferase (MGMT) is an important resistance factor, and that inactivation of MGMT would sensitize neuroblastoma cells to these agents.Experimental Design: MGMT protein expression was assessed in 74 primary neuroblastoma tumors. Growth inhibition assays were done to determine the IC50 and the extent of synergy observed with various concentrations of temozolomide, irinotecan, and the MGMT-inactivating agent O6-benzylguanine, using cultured syngeneic neuroblastoma cells with either low or high levels of MGMT expression. We then assessed efficacy in a mouse xenograft model of metastatic neuroblastoma.Results: MGMT was expressed by all 74 tumors evaluated. Pretreatment of neuroblastoma cells with O6-benzylguanine reduced the IC50 of temozolomide by 10-fold regardless of level of MGMT expression, and pretreatment with BG followed by temozolomide + irinotecan further reduced the IC50 in cells with high MGMT expression another 10-fold, to well below clinically achievable concentrations. The combination index was 0.27 to 0.30 for all three drugs in both cell lines, indicating strong synergy. Survival at 100 days for mice with metastatic neuroblastoma was 56% with three-drug treatment, compared with untreated controls (0%, P &lt; 0.001) or temozolomide + irinotecan (10%, P = 0.081).Conclusions: MGMT is widely expressed in primary neuroblastoma tumors, and is a relevant therapeutic target. Both in vitro and in vivo studies suggest inactivation of MGMT with O6-benzylguanine may increase the activity of temozolomide and irinotecan against neuroblastoma.
Myeloperoxidase Is a Key Regulator of Oxidative Stress–Mediated Apoptosis in Myeloid Leukemic Cells
Authors: Nakazato Tomonori , Sagawa Morihiko , Yamato Kenji , Xian Mingji , Yamamoto Takehiro , Suematsu Makoto , Ikeda Yasuo , Kizaki Masahiro 
Published: September 2007

Abstract
Purpose: We reported previously that reactive oxygen species (ROS) are key mediators of apoptosis induced by a polyphenol, (−)-epigallocatechin-3-gallate (EGCG), in myeloid leukemic cells. This study aimed to further examine the mechanism of ROS-mediated apoptosis induced by EGCG and its relationship to the heme enzyme myeloperoxidase (MPO).
Experimental Design: We established stably transfected K562 cells expressing wild-type and mutant MPO. Then, sensitivity against EGCG and other ROS-inducing agent was examined and further investigated the detailed molecular mechanism of ROS-inducing apoptosis in MPO-positive leukemic cells.
Results: EGCG rapidly induced apoptosis in MPO-positive leukemia cells. Preincubation of myeloid leukemic cells with the MPO-specific inhibitor, 4-aminobenzoic acid hydrazide, and the heme biosynthesis inhibitor, succinylacetone, resulted in inhibition of the intracellular MPO activity, ROS production, and induction of apoptosis following addition of EGCG. Overexpression of MPO sensitized EGCG-resistant K562 cells to apoptosis induced by EGCG. In contrast, an enzymatically inactive MPO mutant–expressing K562 cell could not respond to EGCG, suggesting that MPO is important for determining the sensitivity to EGCG-induced oxidative stress. Hypochlorous acid scavengers and the hydroxyl radical (·OH) scavenger inhibited EGCG-induced apoptosis in myeloid leukemic cells. The fluorescence intensity of both aminophenyl fluorescein– and hydroxyphenyl fluorescein–loaded myeloid leukemic cells significantly increased on stimulation with EGCG, indicating that EGCG generated highly toxic ROS in myeloid leukemic cells.
Conclusions: These results indicated that highly toxic ROS such as ·OH generated via the hydrogen peroxide/MPO/halide system induce apoptosis and that ROS may be the direct mediators of EGCG-induced apoptosis in MPO-positive leukemic cells.
Activation of the Interleukin-6/STAT3 Antiapoptotic Pathway in Esophageal Cells by Bile Acids and Low pH: Relevance to Barrett's Esophagus
Authors: Dvorak Katerina , Chavarria Melissa , Payne Claire M. , Ramsey Lois , Crowley-Weber Cara , Dvorakova Barbora , Dvorak Bohuslav , Bernstein Harris , Holubec Hana , Sampliner Richard E. , Bernstein Carol , Prasad Anil , Green Sylvan B. , Garewal Harinder 
Published: September 2007

AbstractObjectives: The molecular factors contributing to the development of Barrett's esophagus (BE) are unclear. Our previous studies showed that BE tissues secrete interleukin-6 (IL-6) and express proteins associated with IL-6 signaling, including IL-6 receptor, activated signal transducer and activators of transcription 3 (STAT3), and antiapoptotic proteins Bcl-xL and Mcl-1. Here, we test the hypothesis that bile acids and gastric acids, two components of refluxate associated with gastresophageal reflux disease, activate the IL-6/STAT3 pathway.Materials and Methods: Immunohistochemistry was used to assess levels of phosphorylated STAT3 in esophageal tissue samples from BE patients with different grades of dysplasia. Seg-1 esophageal adenocarcinoma cells were evaluated for STAT3 activation and IL-6 and Bcl-xL expression by molecular biology techniques, including Western blot, reverse transcription–PCR, and ELISA after exposure to control media (pH 7.4), media supplemented with a 0.1 mmol/L bile acid cocktail with media at pH 4 or media at pH 4 with bile acid cocktail.Results: Immunohistochemical analysis showed that activated, phosphorylated STAT3 is expressed in nuclei of dysplastic BE and cancer tissues. Treatment of Seg-1 cells with media containing bile acid cocktail and acidified to pH 4 resulted in increased activation of STAT3, IL-6 secretion, and increased expression of Bcl-xL. Inhibition of the STAT3 pathway using STAT3 small interfering RNA or Janus-activated kinase inhibitor resulted in increased apoptosis.Conclusions: The IL-6/STAT3 antiapoptotic pathway is induced by short exposure to bile acid cocktail and low pH. This alteration, if persistent in vivo, may underlie the development of dysplastic BE and tumor progression.
Low-Dose Paclitaxel Prior to Intratumoral Dendritic Cell Vaccine Modulates Intratumoral Cytokine Network and Lung Cancer Growth
Authors: Zhong Hua , Han Baohui , Tourkova Irina L. , Lokshin Anna , Rosenbloom Alan , Shurin Michael R. , Shurin Galina V. 
Published: September 2007

Abstract
Purpose: The main goal of this study was to provide the “proof-of-principle” that low-dose paclitaxel is able to change the tumor microenvironment and improve the outcome of intratumoral dendritic cell vaccine in a murine lung cancer model.
Experimental Design: We evaluated the antitumor potential and changes in the intratumoral milieu of a combination of low-dose chemotherapy and dendritic cell vaccine in the Lewis lung carcinoma model in vivo.
Results: The low-dose paclitaxel, which induced apoptosis in ∼10% of tumor cells, was not toxic to bone marrow cells and dendritic cells and stimulated dendritic cell maturation and function in vitro. Although tumor cells inhibited dendritic cell differentiation in vitro, this immunosuppressive effect was abrogated by the pretreatment of tumor cells with low-dose paclitaxel. Based on these data, we next tested whether pretreatment of tumor-bearing mice with low-dose paclitaxel in vivo would improve the antitumor potential of dendritic cell vaccine administered intratumorally. Significant inhibition of tumor growth in mice treated with low-dose paclitaxel plus intratumoral dendritic cell vaccine, associated with increased tumor infiltration by CD4+ and CD8+ T cells and elevated tumor-specific IFN-γ production by draining lymph node cells, was revealed. Using a novel intratumoral microdialysis technique and Luminex technology for collecting and characterizing soluble factors released within the tumor bed for several days in live freely moving animals, we showed that low-dose paclitaxel altered the cytokine network at the tumor site.
Conclusions: Our data indicate that low-dose chemotherapy before intratumoral delivery of dendritic cells might be associated with beneficial alterations of the intratumoral microenvironment and thus support antitumor immunity.
Phase I Trial of MS-275, a Histone Deacetylase Inhibitor, Administered Weekly in Refractory Solid Tumors and Lymphoid Malignancies
Authors: Kummar Shivaani , Gutierrez Martin , Gardner Erin R. , Donovan Erin , Hwang Kyunghwa , Chung Eun Joo , Lee Min-Jung , Maynard Kim , Kalnitskiy Mikhail , Chen Alice , Melillo Giovanni , Ryan Qin C. , Conley Barbara , Figg William D. , Trepel Jane B. , Zwiebel James , Doroshow James H. , Murgo Anthony J. 
Published: September 2007

Abstract
Purpose: MS-275 is a histone deacetylase inhibitor that has shown potent and unique anticancer activity in preclinical models. The aims of this phase I trial were to determine the dose-limiting toxicities and maximum tolerated dose of oral MS-275 in humans administered with food on a once weekly schedule and to study the pharmacokinetics of oral MS-275.
Experimental Design: Patients with refractory solid tumors and lymphoid malignancies were treated with oral MS-275 on a once weekly schedule for 4 weeks of a 6-week cycle. Samples for pharmacokinetic and pharmacodynamic analyses were collected during cycle 1. Protein acetylation in subpopulations of peripheral blood mononuclear cells was measured using a multivariable flow cytometry assay.
Results: A total of 22 patients were enrolled, and 19 were considered evaluable for toxicity. The maximum tolerated dose was 6 mg/m2. No National Cancer Institute Common Toxicity Criteria grade 4 toxicities were observed. Dose-limiting grade 3 toxicities were reversible and consisted of hypophosphatemia, hyponatremia, and hypoalbuminemia. Non–dose-limiting grade 3 myelosuppression was also observed. The mean terminal half-life of MS-275 was 33.9 ± 26.2 and the Tmax ranged from 0.5 to 24 h. Although there was considerable interpatient variability in pharmacokinetics, the area under the plasma concentration versus time curve increased linearly with dose.
Conclusions: MS-275 is well tolerated at a dose of 6 mg/m2 administered weekly with food for 4 weeks every 6 weeks. Drug exposure increases linearly with dose, and protein acetylation increased in all the subpopulations of peripheral blood mononuclear cells following MS-275 administration.
Cytotoxic T-Lymphocyte–Associated Antigen-4
Authors: Hodi F. Stephen 
Published: September 2007

Abstract
Previously, the development of immune-based therapies has primarily focused on vaccines and cytokines, yielding benefit in a small percentage of patients. Recent advances in our understanding of the function of costimulatory molecules have revitalized enthusiasm in the development of immune therapies for cancer. This family of proteins possesses properties involved in both lymphocyte activation and immune-inhibitory functions. The costimulatory molecule with the greatest translation into the clinic thus far is CTL-associated antigen-4 (CTLA-4). CTLA-4 engagement leads to T-cell inhibition by two principle mechanisms. The first involves competitive binding with CD28 for B7 on the antigen-presenting cell. The second is direct intracellular inhibitory signals mediated by the CTLA-4 cytoplasmic tail. Numerous clinical trials testing the blockade of CTLA-4 signaling with fully human monoclonal antibodies have treated a variety of cancers, with the most experience in the treatment of metastatic melanoma. Significant antitumor activity as well as potential autoimmune-related toxicities have been observed. Further clinical investigation with CTLA-4 blockade, planned clinical trials testing manipulation of other costimulatory molecules, and continued improvement in understanding of costimulatory pathways present a new era of immune therapies for cancer patients.
Improved Tumor Targeting and Decreased Normal Tissue Accumulation through Extracorporeal Affinity Adsorption in a Two-Step Pretargeting Strategy
Authors: Mårtensson Linda , Nilsson Rune , Ohlsson Tomas , Sjögren Hans-Olov , Strand Sven-Erik , Tennvall Jan 
Published: September 2007

Abstract
Purpose: Evaluation of the possibilities of reducing the accumulation of radiolabeled streptavidin in radiosensitive organs by extracorporeal affinity adsorption (ECAT).
Experimental Design: Rats were injected with biotinylated antibody and subjected to removal of the antibodies from the circulation by ECAT 24 h after injection (avidin column). Animals were then injected with 111In-1,4,7,10-tetra-azacylododecane N,N′,N″,N‴-tetraacetic acid (DOTA)-streptavidin. In a third step, animals were subjected to a second ECAT 8 h after injection to remove the DOTA-streptavidin from the circulation (biotin column). Biodistribution and tumor targeting of DOTA-streptavidin 24 h after injection was determined.
Results: Elimination of biotinylated antibody by ECAT before injection of DOTA-streptavidin increased the tumor targeting by 50%. In addition, the levels of DOTA-streptavidin in liver and lymph nodes were reduced by 60%, which implied a 4.3- and 3.8-fold increase of tumor-to-liver and tumor-to-lymph node ratios, respectively. By doing a second ECAT to remove DOTA-streptavidin from the circulation, accumulation in normal tissues was reduced. However, this latter ECAT also reduced tumor accumulation by 25% (mostly corresponding to radioactivity in the circulation).
Conclusions: ECAT was efficient as a means of removing biotinylated antibodies and would probably also be efficient for the clearance of streptavidin-conjugated antibodies. Conversely, the use of ECAT for removal of radiolabeled streptavidin seems not to offer any advantage.