bluuebunny/crossref_metadata_2025_split huggingface dataset:
Abstract C249: Down-regulation of the HIF pathway enhances anti-tumor effects of the mTOR inhibitor ridaforolimus in the Her2/Neu mouse model of breast cancer
Authors: Di Bacco Alessandra , C. Artime Marlene , Gargano Diana , Menon Mary-Kamala , Rao Sudhir , Zhang Weisheng , Haines Brian B. , Marszalek Joseph 
Published: June 2012

Abstract
The Hypoxia-inducible Factor (HIF) pathway is a unique target in cancer because it controls multiple processes involved in tumor progression including neovascularization, tumor cell metabolism, invasion and metastasis. Hypoxia is elevated in a variety of tumor types and associated with resistance to therapeutics resulting in poor prognoses for patients. While a variety of tumor xenograft tumor models have demonstrated sensitivity to HIF pathway inhibition, studies in transgenic mouse models may provide a better understanding of the response as it more closely resembles the disease. Here we evaluate the role of HIF pathway in the MMTV-Neu transgenic (NeuT) breast cancer model and influence of the HIF pathway on response to the mTOR inhibitor ridaforolimus/MK-8669. A HIF regulated neuT model was generated by crossing NeuT transgenic mouse with one expressing a doxycyline-inducible HIF1β shRNA (NeuT-HIF1β) (Taconic-Artemis, Cologne, Germany). HIF1β is the obligate heterodimerization partner for the HIFα subunits and is required for HIF pathway activity. Upon derepression of the HIF1β shRNA by doxycycline treatment, greater than 80% knockdown is observed in most tissues. After 21-days of shRNA induction, tumor growth suppression was observed in the doxycyline-treated NeuT-HIF1β mice, but not NeuT littermate control mice. Growing evidence suggests that in hypoxia mTOR activity is often inhibited by HIF dependent and independent mechanisms. To evaluate the effect of hypoxia on the sensitivity of cells to a mTOR inhibitor, four cell lines (C786; U251; H1915; SKLU1) were treated with ridaforolimus cultured under normoxic (21% oxygen) and hypoxic (0.1% oxygen) conditions, the later oxygen concentration observed in hypoxic region of tumors. Under normoxia, the growth rate for all four cell lines was reduced by ridaforolimus. Under hypoxia, two lines were unaffected (786; U251) by ridaforolimus, while the other (H1915; SKLU1) remained sensitive. Histological analysis of the neuT tumors revealed that PI3K/mTOR and HIF pathways activities are mutually exclusive in these tumors. PI3K/mTOR pathway activity was detected in normoxic regions and HIF pathway activity present only in hypoxic regions. Thus we hypothesized targeting both pathways should achieve a far greater effect than each treatment separately. Treatment of mice with HIF1β knockdown or ridaforolimus resulted in 2-fold reduction in tumor growth and the combination resulted in a 4-fold decrease when both two pathways were targeted together. Histological analysis of these tumors will be discussed. In conclusion these data demonstrate that the effect of ridaforolimus on tumor growth can be improved by combining treatment that reduces the level of HIF pathway activity in tumors.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C249.
Abstract C32: First-in-human clinical, pharmacokinetic (PK) and pharmacodynamic (PD) phase I study of the first-in-class spliceosome inhibitor E7107 administered IV (bolus) on days 1, 8, and 15 every 28 days to patients with solid tumors
Authors: Eskens Ferry A. , Ramos Francisco J. , Burger Herman , de Jonge Maja JA , Wanders Jantien , Lopez-Anaya Arturo , Baselga Jose , Tabernero Josep 
Published: June 2012

Abstract
Background: E7107 is a first-in-class inhibitor of the spliceosome, most likely by interacting with spliceosome-associated protein-130 (SAP 130). Splicing removes intron sequences from pre-mRNA and exons are fused resulting in the formation of mature mRNA. Alternative splicing frequently encodes oncoproteins. E7107 interferes the maturation process of pre-mRNA to mRNA, with consequent changes in protein expression profiles.
Methods: Objectives of this study were to explore (1) tolerability and safety profile, (2) PK, (3) PD effects on pre-mRNA splicing, and (4) anti tumor activity of E7107 administered as bolus infusion on days 1, 8, 15 of a 28-day schedule
Results: 36 patients (21M/15F, median age 61yrs (45–79)) received E7107 doses of 0.6 mg/m2 (n=4), 0.9 mg/m2 (n=3), 1.3 mg/m2 (n=3), 2.0 mg/m2 (n=3), 3.0 mg/m2 (n=4), 4.5 mg/m2 (n=3) and 4.0 mg/m2 (n=16). At 4.5 mg/m2 two episodes of DLT (grade 3 and 4 diarrhea) and at 4.0 mg/m2 one episode of DLT (a combination of grade 3 nausea, vomiting and abdominal cramps) were observed. Other frequently occurring side effects were mainly gastrointestinal. After drug discontinuation, one patient at 4.0 mg/m2 experienced reversible grade 4 blurred vision. The maximum tolerable dose (MTD) is 4.0 mg/m2. No complete or partial responses were observed. Pharmacokinetic analysis revealed large volume of distribution (Vss: 279 to 1369 L), high systemic clearance (CL: 111 to 253 L/hr), and moderate elimination half-life (t1/2: 5.3 to 15.1 hr). Systemic exposure on days 1 and 15 (Cmax, AUC0-∞) increased in a dose-dependent manner. At the MTD, mRNA levels of selected target genes (TRAPPC4, SLC25A19, GTF2H1), monitored in PBMC's, showed a 15–25-fold decrease, whereas unspliced pre-mRNA levels of DNAJB1 and EIF4A1 showed a 10–25-fold increase. Notably, at days 1 and 15, modulations generally peaked at 2–6 hr after end of the infusion and almost completely recovered to base-line levels at 24–48 hr.
Conclusion: The MTD for E7107 using this schedule is 4.0 mg/m2. PK is dose-dependent and reproducible within subjects. PD analysis revealed dose-dependent reversible inhibition of pre-mRNA processing of target genes, confirming proof-of-principle activity of E7107.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C32.
Abstract C34: p53 overexpression is correlated with poor outcome in premenopausal women with breast cancer treated with tamoxifen after chemotherapy
Authors: Yom Cha Kyong , Kim Hee Jeong , Kim Jun Ho , Ahn Sei Hyun , Park Yong Lai , Kim Hee Sung 
Published: June 2012

Abstract
Purpose: The aims of this study were to evaluate the difference in outcomes based on p53 overexpression of breast cancer patients who received adjuvant therapy following local treatment for invasive ductal carcinoma, not otherwise specified (NOS).
Patients and Methods: We analyzed data from 4,683 cancer patients enrolled in 2 institutions between 1997 and 2006. We analyzed the correlation between p53 overexpression and relapse, response to adjuvant therapy, breast cancer-specific survival (BCSS), and relapse-free survival (RFS) in patients with primary breast cancer.
Results: p53 overexpression was noted in 1,091 patients (23.3%). A significant correlation existed between p53 overexpression and poor prognostic factors, an increased frequency of regional recurrence, visceral metastasis, and worse BCSS and RFS. Based upon subgroup analyses, combined age (&lt; 35 years, 35–50 years, and &gt; 50 years) and adjuvant therapy (hormone therapy only, chemotherapy only, and hormone therapy following chemotherapy), the greatest reduction of survival based on p53 overexpression was noted in patients 35–50 years of age who received hormone therapy following chemotherapy (p&lt;0.05). Multivariate analysis showed that p53 overexpression is an independent prognostic factor in patients treated with hormone therapy and chemotherapy (relative risk for BCSS, 2.003; 95% CI, 1.105–3.631; p=0.022).
Conclusion: p53-overexpressing breast cancer patients between 35 and 50 years of age who received tamoxifen following chemotherapy had the greatest adverse effect on outcome. p53 overexpression is significantly associated with tamoxifen-resistance in premenopausal women with breast cancer.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C34.
Abstract C62: Identification of GSK2126458, a highly potent inhibitor of phosphoinositide 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR)
Authors: Knight Steven D. , Adams Nicholas D. , Burgess Joelle L. , Chaudhari Amita M. , Darcy Michael G. , Donatelli Carla A. , Newlander Ken A. , Parrish Cynthia A. , Ridgers Lance H. , Sarpong Martha A. , Schmidt Stanley J. , Van Aller Glenn , Carson Jeff D. , Elkins Patricia A. , Diamond Melody , Gardiner Christine M. , Garver Eric , Luo Lusong , Raha Kaushik , Sung Chiu-Mei , Tummino Peter J. , Auger Kurt R. , Dhanak Dashyant 
Published: June 2012

Abstract
Phosphoinositide 3-kinase (PI3K) is a critical regulator of cell growth and transformation and its signaling pathway is one of the most commonly mutated pathways in human cancer. The mammalian target of rapamycin (mTOR), a class IV PI3K protein kinase, is also a central regulator of cell growth, and mTOR inhibitors are believed to augment the antiproliferative efficacy of the PI3K/AKT pathway. GSK1059615, our first PI3K clinical compound, progressed to a dose escalation study in patients with refractory malignancies. Following the discovery of GSK1059615, we sought to identify a second inhibitor with improved potency, selectivity, and pharmacokinetics. Key to our approach to achieving the desired levels of PI3K activity was to pursue structure-based design utilizing crystallography of the more amenable PI3K as a surrogate protein. Following a chemistry lead optimization effort, the pyridylsulfonamide GSK2126458 was identified as a highly potent, orally bioavailable, pan-PI3K and mTOR inhibitor (PI3K app Ki = 19 pM; mTORC1 app Ki = 180 pM; mTORC2 app Ki = 300 pM). Consistent with potent PI3K and mTORC2 enzyme inhibition, GSK2126458 decreased cellular levels of phosphorylated AKT (BT474 pAKT IC50 = 180 pM) and inhibited cell proliferation in a large panel of cancer cell lines (e.g. BT474 growth IC50 = 2 nM). GSK2126458 showed good exposure in four pre-clinical animal species and exhibited in vivo activity in both pharmacodynamic and tumor growth efficacy models. GSK2126458 is being evaluated currently in human clinical trials for the treatment of cancer. The discovery, design, and optimization of GSK2126458 and related analogs will be presented.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C62.
Abstract C68: Endogenous expression of an oncogenic PI3K mutation leads to epithelial-mesenchymal transition (EMT) and invasiveness
Authors: Wallin Jeffrey J. , Guan Jane , Haverty Pete , Modrusan Zora , Arena Sabrina , Yao Evelyn , Hoeflich Klaus P. , Bardelli Alberto , Torrance Christopher , Belvin Marcia , Friedman Lori S. 
Published: June 2012

Abstract
The PTEN/PI3K pathway is commonly mutated in cancer and therefore represents a therapeutic target. In order to investigate the primary phenotypes mediated by mutant PIK3CA in a controlled and patient-relevant context, we utilized human non-tumorigenic MCF10A parental and isogenic knock-in cell lines that harbor a common activating PIK3CA mutation (H1047R). We found that endogenous introduction of a mutated PIK3CA allele results in a marked epithelial-mesenchymal transition (EMT) and invasive phenotype compared to isogenic wild-type cells. Moreover, a potent and selective inhibitor of PIK3CA (GDC-0941) was highly effective in reversing this phenotype in 3D cell culture. Our results suggest that invasion assays and biomarkers should be used to reveal PIK3CA ‘oncogeneaddiction’ responses of pathway-targeted agents.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C68.
Abstract C70: Targeting tumor cell glycolysis: Discovery and characterization of small molecule inhibitors of IPFK2 (Inducible 6-Phosphofructo-2-Kinase)
Authors: Markby David W. 
Published: June 2012

Abstract
Background: Cancer cells frequently show high rates of glycolysis even under normoxic conditions (the Warburg effect). Cellular glycolytic flux is regulated in part at the level of 6-phosphofructo-1-kinase (PFK1) by a potent allosteric activator, fructose-2,6-bisphosphate (F2,6BP), whose concentration is controlled by a family of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatases (PFKFB1–4). Among the isozymes, PFKFB3 (or inducible 6-phosphofructo-2-kinase, IPFK2) exhibits the highest ratio of kinase to phosphatase activity and has been implicated in cancer progression by tumor overexpression and siRNA interference studies. Hence, inhibition of IPFK2 activity may selectively target tumor metabolism by blocking glycolysis and cell proliferation.
Methods: Small molecule inhibitors of IPFK2 were identified by high-throughput screening and lead optimization using in vitro enzymatic assays and cellular assays for F2,6BP. Glycolytic pathway activity was monitored by lactate production, extracellular acidification rate (ECAR), and cellular F1,6BP level. Mitochondrial function was assessed by measuring oxygen consumption rate (OCR) and mitochondrial membrane potential (MMP). Cellular ATP level was used to assess short term effects on bioenergetics and long term effects on viability. PFKFB activity in vivo in tumor xenografts and normal tissue was measured by F2,6BP level.
Conclusions: IPFK2 inhibitors displayed potent biochemical activity (IC50 1–10 nM) and were competitive with ATP and noncompetitive against fructose-6-phosphate. Treatment of cells with IPFK2 inhibitors reduced cellular F2,6BP levels with IC50 values 50–500 nM under both normoxia and hypoxia, consistent with specific knockdown of IPFK2 in siRNA experiments. IPFK2 inhibitors reduced glycolytic flux as assessed by ECAR and cellular F1,6BP levels, although the extent of inhibition varied widely among cell lines. Short term treatment with these compounds generally did not inhibit mitochondrial function (as assessed by OCR and MMP) or reduce cellular ATP levels. Longer term treatment with IPFK2 inhibitors reduced tumor cell viability under low serum conditions. In vivo pharmacodynamic studies with orally bioavailable compounds demonstrated target inhibition in mouse xenograft tumor models as assessed by a reduction in F2,6BP. Further lead optimization and biological characterization is underway with the goal of identifying an IPFK2-selective glycolytic inhibitor for development as a cancer therapeutic.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C70.
Abstract C8: Short-chain fatty acids induce autophagy through inhibition of mTOR pathway
Authors: Tang Yong , Chen Yakun , Jiang Hongmei , Nie Daotai 
Published: June 2012

Abstract
Short-chain fatty acid (SCFA), mainly propionate and butyrate are major by-products of the bacterial fermentation of undigested dietary fiber in the human large intestine. Evidence to date implicates propionate/butyrate as inhibitors of colon cancer cell proliferation and inducers of apoptotic cell death. In this study, we demonstrated that propionate/butyrate was able to induce another type of programmed cell death named autophagy in human colon cancer HCT116 cells. Propionate/butyrate-treated cells exhibited extensive characteristics of autophagy, namely the conversion of LC3-I into LC3-II, reduced expression of p62/ SQSTM1; redistribution of GFPLC3 fusion protein from a diffuse pattern towards autophagosomes, which became visible as cytoplasmic puncta; and increased acidic vesicular organelle development as manifested by dramatically increased quantity of strongly stained punctate areas reflected by LysoTracker staining and monodansylcadaverine (MDC) incorporation. Propionate/butyrate-induced autophagy was based on inhibition of its negative regulator-mTOR pathway as evidenced by dephosphorylation of p70S6K and 4E-BP1 and was marked by increased phosphorylation of AMP kinase, two events known to be linked to autophagy. Activation of AMPK was associated with a fluctuation of intracellular ATP, during which the level of ATP transiently increased following propionate/butyrate exposure, reaching maximum at 5 hours, and then declined in slow but gradual manner. The decline of ATP may be due to compromised mitochondria membrane potential and enhanced cellular reactive oxygen species generation. We also showed that this autophagic increase was associated with a series of changes in metabolic pathways, in which energy-demanding program (fatty acids composition and glycogen synthesis inhibition) was downregulated whereas energy-producing program (mitochondria biogenesis) was initiated to cope with the energy crisis. Finally, we showed that increased autophagy and mTOR inhibition by propionate/butyrate are not dependent on p53 activation. Altogether, this study demonstrates autophagy as a novel programmed cell death pathway for propionate/butyrate induced cell death.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C8.
Abstract C84: Inhibition of cholesterol esterification by fenretinide in osteosarcoma in vitro
Authors: Gasperi-Campani Anna , Roncuzzi Laura , Baiocchi Daniela , Putzolu Marirosa , Baldini Nicola , Giunti Armando , Dessì Sandra 
Published: June 2012

Abstract
Osteosarcoma remains the most common primary malignant bone cancer affecting children and adolescents. Although the combination of systemic chemotherapy and surgery enables long-term survival in most cases, the poor prognosis of patients with metastatic or recurrent disease and the lack of establishment of second-line chemotherapy suggest that novel therapeutic strategies for this tumor are needed. Here we show that fenretinide, a synthetic derivative of all-trans-retinoic acid, is active against osteosarcoma in vitro, at concentrations identical or lower to those detectable in breast cancer patients plasma during chemopreventive clinical trials. Cell lines were HOS and MG63, known to be resistant to methotrexate and cyclophosphamide, drugs in use in osteosarcoma treatment. We demonstrate for the first time that fenretinide is active in this tumor and that the molecular basis of fenretinide activity is the inhibition of cholesterol esterification, with down-regulation of ACAT and MDR1 mRNA, followed by downregulation of caveolin-1 protein expression. This result is in line with our recent results obtained in VSMC and in leukemia cells. The confirmation and extention of these data to different human tumors will provide evidence of a novel mechanism of either cancer or human vascular proliferation disease control by the inhibition of cholesterol esterification. Grants from MIUR, Carisbo Foundation, Pallotti's Legacy for Cancer Research and University of Bologna.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C84.
Abstract C88: Imiquimod induces reactive oxygen species- and caspase-independent cell cycle arrest and apoptosis in MDA-MB-468 breast cancer cells
Authors: Greenshields Anna L. , Hoskin David W. 
Published: June 2012

Abstract
Imiquimod is an immune modulator currently used as a topical treatment for superficial basal cell carcinoma. Recently, apoptosis-inducing activity in neoplastic cells has been attributed to imiquimod at doses over a 1000-fold lower than those used in topical applications. The present study examined the direct effect of imiquimod on MDA-MB-468 breast cancer cells. Oregon Green 488 staining of imiquimod-treated MDA-MB-468 cells indicated that imiquimod had a dose-dependent, anti-proliferative effect; cell cycle analysis indicated that arrest occurred in S phase after 72 h exposure to imiquimod. In addition, imiquimod had a time- and dose-dependent cytotoxic effect on a panel of breast cancer cells (MDA-MB-468, MDA-MB-231, MCF-7, and T47D). Double staining of imiquimod-treated MDA-MB-468 cells using Annexin-V-FLOUS and propidium iodide indicated that imiquimod caused apoptosis, while the lack of lactate dehydrogenase release confirmed the absence of necrosis. Unlike previously reported data for other neoplastic cells, imiquimod-induced apoptosis was not caspase-dependent in MDA-MB-468 cells; however, DiOC6 staining revealed destabilization of the mitochondrial membrane following imiquimod treatment. Pretreatment with reduced glutathione did not rescue MDA-MB-468 cells from imiquimod-induced apoptosis, indicating that reactive oxygen species were not required for imiquimod-induced cytotoxicity. Western blotting showed that imiquimod-treated MDA-MB-468 cells had increased cytosolic cytochrome c and PARP cleavage compared to controls, which was consistent with induction of the mitochondrial pathway of apoptosis. These data suggest that imiquimod exerts a significant caspase-independent apoptosis-promoting effect on breast cancer cells.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C88.
Abstract C98: Blocking glycolysis with 2-deoxy-D-glucose prodrugs to target brain tumors: A novel concept
Authors: Priebe Waldemar , Cybulski Marcin , Fokt Izabela , Skora Stanislaw , Conrad Charles A. , Madden Timothy 
Published: June 2012

Abstract
Glycolysis is the major energy producing pathway for fast growing, glycolytically dependent tumors, such as gliomas and ependymomas. Blocking glycolysis is, therefore, an important therapeutic strategy when used alone or as a combination therapy to enhance the effects of chemotherapy in energy-starved tumors. In our previous studies, we examined D-glucose-based antimetabolites, including 2-deoxy-D-glucose (2-DG), and confirmed their ability to block glycolysis, discovered that they can induce autophagic cell death in vitro, and established their antitumor activity in vivo in an orthotopic glioma model.
However, during our evaluation of 2-DG, we determined that these compounds do not possess sufficient drug-like properties (reasonable biostability, pharmacokinetic characteristics, or distribution to the target) to warrant further investigations into their clinical effectiveness. In an attempt to improve the pharmacokinetic profile of 2-DG, we have designed synthesized, and tested a series of ester-type prodrugs that enhance biostability, biodistribution, and delivery of 2-DG to its CNS target. We will present the synthesis and preliminary evaluation of these compounds, leading to the selection of WP1122 as our lead compound for further drug development. We will also present the subsequent evaluation of WP1122 in vivo in orthotopic brain tumor models and demonstrate its superior pharmacokinetic profile and enhanced CNS uptake.
Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C98.