bluuebunny/crossref_metadata_2025 huggingface dataset:
Simultaneous Visualization of Protumorigenic Src and MT1-MMP Activities with Fluorescence Resonance Energy Transfer
Authors: Ouyang Mingxing , Huang He , Shaner Nathan C. , Remacle Albert G. , Shiryaev Sergey A. , Strongin Alex Y. , Tsien Roger Y. , Wang Yingxiao
Published: March 2010

Both Src kinase and membrane type 1 matrix metalloproteinase (MT1-MMP) play critical roles in cancer invasion and metastasis. It is not clear, however, how the spatiotemporal activation of these two critical enzymes is coordinated in response to an oncogenic epithelial growth factor (EGF) stimulation. Here, we have visualized the activities of Src and MT1-MMP concurrently in a single live cell by combining two fluorescence resonance energy transfer (FRET) pairs with distinct spectra: (a) cyan fluorescent protein (CFP) and yellow FP (YFP), and (b) orange FP (mOrange2) and red FP (mCherry). The new FRET pair, mOrange2 and mCherry, was first characterized in vitro and in cultured mammalian cells. When integrated with the CFP/YFP pair, this new pair allowed the revelation of an immediate, rapid, and relatively dispersed Src activity. In contrast, the MT1-MMP activity displayed a slow increase at the cell periphery, although Src was shown to play a role upstream to MT1-MMP globally. This difference in the activation patterns of MT1-MMP and Src in response to EGF is further confirmed using an optimized MT1-MMP biosensor capable of being rapidly cleaved by MT1-MMP. The results indicate that although Src and MT1-MMP act globally in the same signaling pathway, their activations differ in space and time upon EGF stimulation, possibly mediated by different sets of intermediates at different subcellular locations. Our results also showed the potential of mOrange2/mCherry as a new FRET pair, together with the popular variants of CFP and YFP, for the simultaneous visualization of multiple molecular activities in a single live cell. Cancer Res; 70(6); 2204–12
Disruption of Laminin-Integrin-CD151-Focal Adhesion Kinase Axis Sensitizes Breast Cancer Cells to ErbB2 Antagonists
Authors: Yang Xiuwei H. , Flores Ludmila M. , Li Qinglin , Zhou Pengcheng , Xu Fenghui , Krop Ian E. , Hemler Martin E.
Published: March 2010

Resistance to anti-ErbB2 agents is a significant problem in the treatment of human ErbB2+ breast cancers. We show here that adhesion of human ErbB2+ breast cancer cells to basement membrane laminin-5 provides substantial resistance to trastuzumab and lapatinib, agents that respectively target the extracellular and kinase domains of ErbB2. Knockdown of laminin-binding integrins (α6β4, α3β1) or associated tetraspanin protein CD151 reversed laminin-5 resistance and sensitized ErbB2+ cells to trastuzumab and lapatinib. CD151 knockdown, together with trastuzumab treatment, inhibited ErbB2 activation and downstream signaling through Akt, Erk1/2, and focal adhesion kinase (FAK). Hence, ErbB2 function in mammary tumor cells is promoted by integrin-mediated adhesion to laminin-5, with strong support by CD151, leading to signaling through FAK. Consequently, removal or inhibition of any of these components (laminin-5, integrin, CD151, FAK) markedly sensitizes cells to anti-ErbB2 agents. These new insights should be useful when devising strategies for overcoming drug resistance in ErbB2+ cancers. Cancer Res; 70(6); 2256–63
Death Receptor Agonists as a Targeted Therapy for Cancer
Authors: Wiezorek Jeffrey , Holland Pamela , Graves Jonathan
Published: March 2010

Apoptosis is integral to normal, physiologic processes that regulate cell number and results in the removal of unnecessary or damaged cells. Apoptosis is frequently dysregulated in human cancers, and recent advancements in our understanding of the regulation of programmed cell death pathways has led to the development of novel agents to reactivate apoptosis in malignant cells. The activation of cell surface death receptors by tumor necrosis factor–related apoptosis-inducing ligand (Apo2L/TRAIL) and death receptor agonists represent an attractive therapeutic strategy to promote apoptosis of tumor cells through the activation of the extrinsic pathway. The observation that Apo2L/TRAIL can eliminate tumor cells preferentially over normal cells has resulted in several potential therapeutics that exploit the extrinsic pathway, in particular, the soluble recombinant human (rh)Apo2L/TRAIL protein and agonist monoclonal antibodies that target death receptors 4 or 5. Many of these agents are currently being evaluated in phase 1 or 2 trials, either as a single agent or in combination with cytotoxic chemotherapy or other targeted agents. The opportunities and challenges associated with the development of death receptor agonists as cancer therapeutics, the status of ongoing clinical evaluations, and the progress toward identifying predictive biomarkers for patient selection and pharmacodynamic markers of response are reviewed. Clin Cancer Res; 16(6); 1701–8
Value of Magnetic Resonance Spectroscopy Imaging and Dynamic Contrast-Enhanced Imaging for Detecting Prostate Cancer Foci in Men With Prior Negative Biopsy
Authors: Sciarra Alessandro , Panebianco Valeria , Ciccariello Mauro , Salciccia Stefano , Cattarino Susanna , Lisi Danilo , Gentilucci Alessandro , Alfarone Andrea , Bernardo Silvia , Passariello Roberto , Gentile Vincenzo
Published: March 2010

Purpose: This study aimed to prospectively analyze the role of magnetic resonance spectroscopy imaging (MRSI) and dynamic-contrast enhancement magnetic resonance (DCEMR) in the detection of prostate tumor foci in patients with persistently elevated prostate-specific antigen levels (in the range of ≥4 ng/mL to <10 ng/mL) and prior negative random trans-rectal ultrasound (TRUS)-guided biopsy.

Experimental Design: This was a prospective randomized single-center study. One hundred and eighty eligible cases were included in the study. Patients in group A were submitted to a second random prostate biopsy, whereas patients in group B were submitted to a 1H-MRSI-DCEMR examination and samples targeted on suspicious areas were associated to the random biopsy.

Results: At the second biopsy, a prostate adenocarcinoma histologic diagnosis was found in 22 of 90 cases (24.4%) in group A and in 41 of 90 cases (45.5%) in group B (P = 0.01). On a patient-by-patient basis, MRSI had 92.3% sensitivity, 88.2% specificity, 85.7% positive predictive value (PPV), 93.7% negative predictive value (NPV), and 90% accuracy; DCEMR had 84.6 % sensitivity, 82.3% specificity, 78.5% PPV, 87.5% NPV, and 83.3% accuracy; and the association MRSI plus DCEMR had 92.6% sensitivity, 88.8% specificity, 88.7% PPV, 92.7% NPV, and 90.7% accuracy, for predicting prostate cancer detection.

Conclusions: The combination of MRSI and DCEMR showed the potential to guide biopsy to cancer foci in patients with previously negative TRUS biopsy. To avoid a potential bias, represented from having taken more samples in group B (mean of cores, 12.17) than in group A (10 cores), in the future a MRSI/DCEMR directed biopsy could be prospectively compared with a saturation biopsy procedure. Clin Cancer Res; 16(6); 1875–83
A Phase I Pharmacologic Study of Necitumumab (IMC-11F8), a Fully Human IgG1 Monoclonal Antibody Directed Against EGFR in Patients with Advanced Solid Malignancies
Authors: Kuenen Bart , Witteveen Petronella O. , Ruijter Rita , Giaccone Giuseppe , Dontabhaktuni Aruna , Fox Floyd , Katz Terry , Youssoufian Hagop , Zhu Junming , Rowinsky Eric K. , Voest Emile E.
Published: March 2010

Purpose: This study aimed to determine a maximum tolerated dose (MTD) and recommended dose for disease-directed studies of necitumumab (IMC-11F8), a fully human IgG1 monoclonal antibody directed at the epidermal growth factor receptor, and to characterize the safety profile, pharmacokinetics, preliminary antitumor activity, and immunogenicity of necitumumab.

Experimental Design: Patients with advanced solid malignancies were treated with 100 to 1,000 mg (flat dosing) necitumumab followed by a 2-week pharmacokinetics sampling period, before beginning 6-week cycles of therapy.

Results: Sixty patients received necitumumab weekly (29 patients) or every other week (31 patients). Two patients receiving 1,000 mg every 2 weeks experienced dose-limiting toxicities (DLT; grade 3 headache), accompanied by grade 3 nausea and vomiting in one patient. Occurring hours after the initial dose, these DLTs established 800 mg as the MTD. Mild dose-related skin toxicity was the most common drug-related toxicity (80%). One patient in each arm experienced grade 3 acneform rash, which responded to oral antibiotics and topical therapy. Toxicity was similar on both schedules. Necitumumab exhibited saturable elimination and nonlinear pharmacokinetics. At 800 mg (both arms), its half-life was approximately 7 days. All patients treated with ≥600 mg necitumumab achieved target trough concentrations (≥40 μg/mL). Antibodies against necitumumab were not detected. Partial response and stable disease were experienced by 2 and 16 patients, respectively.

Conclusion: Well tolerated, necitumumab is associated with preliminary evidence of antitumor activity, and achieves biologically relevant concentrations throughout the dosing period. The recommended dose of necitumumab for further clinical development is 800 mg (flat dose) weekly or every 2 weeks based on the clinical setting. Clin Cancer Res; 16(6); 1915–23
The Role of the CpG Island Methylator Phenotype in Colorectal Cancer Prognosis Depends on Microsatellite Instability Screening Status
Authors: Dahlin Anna M. , Palmqvist Richard , Henriksson Maria L. , Jacobsson Maria , Eklöf Vincy , Rutegård Jörgen , Öberg Åke , Van Guelpen Bethany R.
Published: March 2010

Purpose: The aim of this study was to relate the CpG island methylator phenotype (CIMP; characterized by extensive promoter hypermethylation) to cancer-specific survival in colorectal cancer, taking into consideration relevant clinicopathologic factors, such as microsatellite instability (MSI) screening status and the BRAF V600E mutation.

Experimental Design: Archival tumor samples from 190 patients from the Northern Sweden Health and Disease Study (NSHDS) and 414 patients from the Colorectal Cancer in Umeå Study (CRUMS), including 574 with cancer-specific survival data, were analyzed for an eight-gene CIMP panel using quantitative real-time PCR (MethyLight). MSI screening status was assessed by immunohistochemistry.

Results: CIMP-low patients had a shorter cancer-specific survival compared with CIMP-negative patients (multivariate hazard ratio in NSHDS, 2.01; 95% confidence interval, 1.20-3.37; multivariate hazard ratio in CRUMS, 1.48; 95% confidence interval, 1.00-2.22). This result was similar in subgroups based on MSI screening status and was statistically significant in microsatellite stable (MSS) tumors in NSHDS. For CIMP-high patients, a shorter cancer-specific survival compared with CIMP-negative patients was observed in the MSS subgroup. Statistical significance was lost after adjusting for the BRAF mutation, but the main findings were generally unaffected.

Conclusions: In this study, we found a poor prognosis in CIMP-low patients regardless of MSI screening status, and in CIMP-high patients with MSS. Although not consistently statistically significant, these results were consistent in two separate patient groups and emphasize the potential importance of CIMP and MSI status in colorectal cancer research. Clin Cancer Res; 16(6); 1845–55
New Developments in Tyrosine Kinase Inhibitor Therapy for Newly Diagnosed Chronic Myeloid Leukemia
Authors: le Coutre Philipp , Schwarz Michaela , Kim Theo D.
Published: March 2010

The biology of chronic myeloid leukemia (CML) has enabled pioneering studies with targeted therapies. BCR-ABL inhibition with imatinib results in high levels of efficacy in patients with newly diagnosed CML in chronic phase (CP), but an estimated 35% of patients could benefit from more effective treatment. Several novel treatment strategies are being investigated in newly diagnosed CML-CP. These strategies include upfront treatment with next-generation tyrosine kinase inhibitors, such as dasatinib, nilotinib, or bosutinib, which also target BCR-ABL but with increased in vitro potency compared with imatinib, and possibly a reduced potential for resistance. Recent in vitro studies have shown that short-term exposure to dasatinib or continuous exposure to imatinib result in equivalent levels of apoptosis, indicating that potent intermittent inhibition is a successful strategy for improving dasatinib tolerability. Modified imatinib regimens are also being investigated in newly diagnosed CML-CP, including higher doses and combination with alternative classes of agents, such as interferon. Existing data suggest that both newer agents and combination approaches can improve treatment responses compared with standard imatinib treatment, although further data are needed, particularly from ongoing phase 3 trials, before the standard of care is revised. Clin Cancer Res; 16(6); 1771–80
Antiangiogenic Activities of 2,5-Dimethyl-Celecoxib on the Tumor Vasculature
Authors: Virrey Jenilyn J. , Liu Zhi , Cho Hee-Yeon , Kardosh Adel , Golden Encouse B. , Louie Stan G. , Gaffney Kevin J. , Petasis Nicos A. , Schönthal Axel H. , Chen Thomas C. , Hofman Florence M.
Published: March 2010

Our laboratory has previously shown that a novel compound, 2,5-dimethyl-celecoxib (DMC), which is structurally similar to the cyclooxygenase-2 (COX-2) inhibitor celecoxib but lacks the COX-2–inhibitory function, mimics the antitumor effects of celecoxib. Most studies on DMC, however, focused on its effects on tumor cells. Here, we investigated the activities of DMC as an antiangiogenic agent in both in vitro and in vivo systems. Using primary cultures of human glioma specimens, we found that DMC treatment was cytotoxic to tumor-associated brain endothelial cells (TuBEC), which was mediated through the endoplasmic reticulum stress pathway. In contrast, confluent cultures of quiescent human BEC did not undergo cell death. DMC potently suppressed the proliferation and migration of the TuBEC. DMC caused no apparent effects on the secretion of vascular endothelial growth factor and interleukin-8 but inhibited the secretion of endothelin-1 in tumor-associated EC. DMC treatment of glioma xenografts in mice resulted in smaller tumors with a pronounced reduction in microvessel density compared with untreated mice. In vitro and in vivo analyses confirmed that DMC has antivascular activity. Considering that DMC targets both tumor cells and tumor-associated ECs, this agent is a promising anticancer drug. Mol Cancer Ther; 9(3); 631–41
Alisol B, a Novel Inhibitor of the Sarcoplasmic/Endoplasmic Reticulum Ca2+ ATPase Pump, Induces Autophagy, Endoplasmic Reticulum Stress, and Apoptosis
Authors: Law Betty Y.K. , Wang Mingfu , Ma Dik-Lung , Al-Mousa Fawaz , Michelangeli Francesco , Cheng Suk-Hang , Ng Margaret H.L. , To Ka-Fai , Mok Anthony Y.F. , Ko Rebecca Y.Y. , Lam Sze Kui , Chen Feng , Che Chi-Ming , Chiu Pauline , Ko Ben C.B.
Published: March 2010

Emerging evidence suggests that autophagic modulators have therapeutic potential. This study aims to identify novel autophagic inducers from traditional Chinese medicinal herbs as potential antitumor agents. Using an image-based screen and bioactivity-guided purification, we identified alisol B 23-acetate, alisol A 24-acetate, and alisol B from the rhizome of Alisma orientale as novel inducers of autophagy, with alisol B being the most potent natural product. Across several cancer cell lines, we showed that alisol B–treated cells displayed an increase of autophagic flux and formation of autophagosomes, leading to cell cycle arrest at the G1 phase and cell death. Alisol B induced calcium mobilization from internal stores, leading to autophagy through the activation of the CaMKK-AMPK-mammalian target of rapamycin pathway. Moreover, the disruption of calcium homeostasis induces endoplasmic reticulum stress and unfolded protein responses in alisol B–treated cells, leading to apoptotic cell death. Finally, by computational virtual docking analysis and biochemical assays, we showed that the molecular target of alisol B is the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase. This study provides detailed insights into the cytotoxic mechanism of a novel antitumor compound. Mol Cancer Ther; 9(3); 718–30
Efficacy of PHA-848125, a Cyclin-Dependent Kinase Inhibitor, on the K-RasG12DLA2 Lung Adenocarcinoma Transgenic Mouse Model: Evaluation by Multimodality Imaging
Authors: Degrassi Anna , Russo Micaela , Nanni Cristina , Patton Veronica , Alzani Rachele , Giusti Anna M. , Fanti Stefano , Ciomei Marina , Pesenti Enrico , Texido Gemma
Published: March 2010

K-ras is the most frequently mutated oncogene in non–small cell lung cancer (NSCLC), the most common form of lung cancer. Recent studies indicate that NSCLC patients with mutant K-ras do not respond to epidermal growth factor receptor inhibitors. In the attempt to find alternative therapeutic regimes for such patients, we tested PHA-848125, an oral pan cyclin-dependent kinase inhibitor currently under evaluation in phase II clinical trial, on a transgenic mouse model, K-RasG12DLA2, which develops pulmonary cancerous lesions reminiscent of human lung adenocarcinomas. We used magnetic resonance imaging and positron emission tomography to follow longitudinally disease progression and evaluate therapeutic efficacy in this model. Treatment of K-RasG12DLA2 mice with 40 mg/kg twice daily for 10 days with PHA-848125 induced a significant tumor growth inhibition at the end of treatment (P < 0.005) and this was accompanied by a reduction in the cell membrane turnover, as seen by 11C-Choline-positron emission tomography (P < 0.05). Magnetic resonance imaging data were validated versus histology and the mechanism of action of the compound was verified by immunohistochemistry, using cyclin-dependent kinase–related biomarkers phospho-Retinoblastoma and cyclin A. In this study, multimodality imaging was successfully used for the preclinical assessment of PHA-848125 therapeutic efficacy on a lung adenocarcinoma mouse model. This compound induced a volumetric and metabolic anticancer effect and could represent a valid therapeutic approach for NSCLC patients with mutant K-ras. Mol Cancer Ther; 9(3); 673–81
IFN-β Restricts Tumor Growth and Sensitizes Alveolar Rhabdomyosarcoma to Ionizing Radiation
Authors: Sims Thomas L. , McGee Mackenzie , Williams Regan F. , Myers Adrianne L. , Tracey Lorraine , Hamner J. Blair , Ng Catherine , Wu Jianrong , Gaber M. Waleed , McCarville Beth , Nathwani Amit C. , Davidoff Andrew M.
Published: March 2010

Ionizing radiation is an important component of multimodal therapy for alveolar rhabdomyosarcoma (ARMS). We sought to evaluate the ability of IFN-β to enhance the activity of ionizing radiation.

Rh-30 and Rh-41 ARMS cells were treated with IFN-β and ionizing radiation to assess synergistic effects in vitro and as orthotopic xenografts in CB17 severe combined immunodeficient mice. In addition to effects on tumor cell proliferation and xenograft growth, changes in the tumor microenvironment including interstitial fluid pressure, perfusion, oxygenation, and cellular histology were assessed.

A nonlinear regression model and isobologram analysis indicated that IFN-β and ionizing radiation affected antitumor synergy in vitro in the Rh-30 cell line; the activity was additive in the Rh-41 cell line. In vivo continuous delivery of IFN-β affected normalization of the dysfunctional tumor vasculature of both Rh-30 and Rh-41 ARMS xenografts, decreasing tumor interstitial fluid pressure, increasing tumor perfusion (as assessed by contrast-enhanced ultrasonography), and increasing oxygenation. Tumors treated with both IFN-β and radiation were smaller than control tumors and those treated with radiation or IFN-β alone. Additionally, treatment with high-dose IFN-β followed by radiation significantly reduced tumor size compared with radiation treatment followed by IFN-β.

The combination of IFN-β and ionizing radiation showed synergy against ARMS by sensitizing tumor cells to the cytotoxic effects of ionizing radiation and by altering tumor vasculature, thereby improving oxygenation. Therefore, IFN-β and ionizing radiation may be an effective combination for treatment of ARMS. Mol Cancer Ther; 9(3); 761–71
ABT-869 Inhibits the Proliferation of Ewing Sarcoma Cells and Suppresses Platelet-Derived Growth Factor Receptor β and c-KIT Signaling Pathways
Authors: Ikeda Alan K. , Judelson Dejah R. , Federman Noah , Glaser Keith B. , Landaw Elliot M. , Denny Christopher T. , Sakamoto Kathleen M.
Published: March 2010

The Ewing Sarcoma (EWS) family of tumors is one of the most common tumors diagnosed in children and adolescents and is characterized by a translocation involving the EWS gene. Despite advances in chemotherapy, the prognosis of metastatic EWS is poor with an overall survival of <30% after 5 years. EWS tumor cells express the receptor tyrosine kinases, platelet-derived growth factor receptor (PDGFR) and c-KIT. ABT-869 is a multitargeted small-molecule inhibitor that targets Fms-like tyrosine kinase-3, c-KIT, vascular endothelial growth receptors, and PDGFRs. To determine the potential therapeutic benefit of ABT-869 in EWS cells, we examined the effects of ABT-869 on EWS cell lines and xenograft mouse models. ABT-869 inhibited the proliferation of two EWS cell lines, A4573 and TC71, at an IC50 of 1.25 and 2 μmol/L after 72 h of treatment, respectively. The phosphorylation of PDGFRβ, c-KIT, and extracellular signal-regulated kinases was also inhibited. To examine the effects of ABT-869 in vivo, the drug was given to mice injected with EWS cells. We observed inhibition of growth of EWS tumor cells in a xenograft mouse model and prolonged survival in a metastatic mouse model of EWS. Therefore, our in vitro and in vivo studies show that ABT-869 inhibits proliferation of EWS cells through inhibition of PDGFRβ and c-KIT pathways. Mol Cancer Ther; 9(3); 653–60
Interactions of the p53 Protein Family in Cellular Stress Response in Gastrointestinal Tumors
Authors: Vilgelm Anna E. , Washington Mary K. , Wei Jinxiong , Chen Heidi , Prassolov Vladimir S. , Zaika Alexander I.
Published: March 2010

p53, p63, and p73 are members of the p53 protein family involved in regulation of cell cycle, apoptosis, differentiation, and other critical cellular processes. Here, we investigated the contribution of the entire p53 family in chemotherapeutic drug response in gastrointestinal tumors. Real-time PCR and immunohistochemistry revealed complexity and variability of expression profiles of the p53 protein family. Using colon and esophageal cancer cells, we found that the integral transcription activity of the entire p53 family, as measured by the reporter analysis, associated with response to drug treatment in studied cells. We also found that p53 and p73, as well as p63 and p73, bind simultaneously to the promoters of p53 target genes. Taken together, our results support the view that the p53 protein family functions as an interacting network of proteins and show that cellular responses to chemotherapeutic drug treatment are determined by the total activity of the entire p53 family rather than p53 alone. Mol Cancer Ther; 9(3); 693–705
Anacardic Acid Inhibits Estrogen Receptor α–DNA Binding and Reduces Target Gene Transcription and Breast Cancer Cell Proliferation
Authors: Schultz David J. , Wickramasinghe Nalinie S. , Ivanova Margarita M. , Isaacs Susan M. , Dougherty Susan M. , Imbert-Fernandez Yoannis , Cunningham Albert R. , Chen Chunyuan , Klinge Carolyn M.
Published: March 2010

Anacardic acid (AnAc; 2-hydroxy-6-alkylbenzoic acid) is a dietary and medicinal phytochemical with established anticancer activity in cell and animal models. The mechanisms by which AnAc inhibits cancer cell proliferation remain undefined. AnAc 24:1ω5 was purified from geranium (Pelargonium × hortorum) and shown to inhibit the proliferation of estrogen receptor α (ERα)–positive MCF-7 and endocrine-resistant LCC9 and LY2 breast cancer cells with greater efficacy than ERα-negative primary human breast epithelial cells, MCF-10A normal breast epithelial cells, and MDA-MB-231 basal-like breast cancer cells. AnAc 24:1ω5 inhibited cell cycle progression and induced apoptosis in a cell-specific manner. AnAc 24:1ω5 inhibited estradiol (E2)–induced estrogen response element (ERE) reporter activity and transcription of the endogenous E2 target genes pS2, cyclin D1, and cathepsin D in MCF-7 cells. AnAc 24:1ω5 did not compete with E2 for ERα or ERβ binding, nor did AnAc 24:1ω5 reduce ERα or ERβ steady-state protein levels in MCF-7 cells; rather, AnAc 24:1ω5 inhibited ER-ERE binding in vitro. Virtual screening with the molecular docking software Surflex evaluated AnAc 24:1ω5 interaction with ERα ligand binding (LBD) and DNA binding (DBD) domains in conjunction with experimental validation. Molecular modeling revealed AnAc 24:1ω5 interaction with the ERα DBD but not the LBD. Chromatin immunoprecipitation experiments revealed that AnAc 24:1ω5 inhibited E2-ERα interaction with the endogenous pS2 gene promoter region containing an ERE. These data indicate that AnAc 24:1ω5 inhibits cell proliferation, cell cycle progression, and apoptosis in an ER-dependent manner by reducing ER-DNA interaction and inhibiting ER-mediated transcriptional responses. Mol Cancer Ther; 9(3); 594–605
Molecular Pharmacology and Antitumor Activity of PHT-427, a Novel Akt/Phosphatidylinositide-Dependent Protein Kinase 1 Pleckstrin Homology Domain Inhibitor
Authors: Meuillet Emmanuelle J. , Zuohe Song , Lemos Robert , Ihle Nathan , Kingston John , Watkins Ryan , Moses Sylvestor A. , Zhang Shuxing , Du-Cuny Lei , Herbst Roy , Jacoby Jörg J. , Zhou Li Li , Ahad Ali M. , Mash Eugene A. , Kirkpatrick D. Lynn , Powis Garth
Published: March 2010

Phosphatidylinositol 3-kinase/phosphatidylinositide-dependent protein kinase 1 (PDPK1)/Akt signaling plays a critical role in activating proliferation and survival pathways within cancer cells. We report the molecular pharmacology and antitumor activity of PHT-427, a compound designed to bind to the pleckstrin homology (PH) binding domain of signaling molecules important in cancer. Although originally designed to bind the PH domain of Akt, we now report that PHT-427 also binds to the PH domain of PDPK1. A series of PHT-427 analogues with variable C-4 to C-16 alkyl chain length were synthesized and tested. PHT-427 itself (C-12 chain) bound with the highest affinity to the PH domains of both PDPK1 and Akt. PHT-427 inhibited Akt and PDPK1 signaling and their downstream targets in sensitive but not resistant cells and tumor xenografts. When given orally, PHT-427 inhibited the growth of human tumor xenografts in immunodeficient mice, with up to 80% inhibition in the most sensitive tumors, and showed greater activity than analogues with C4, C6, or C8 alkyl chains. Inhibition of PDPK1 was more closely correlated to antitumor activity than Akt inhibition. Tumors with PIK3CA mutation were the most sensitive, and K-Ras mutant tumors were the least sensitive. Combination studies showed that PHT-427 has greater than additive antitumor activity with paclitaxel in breast cancer and with erlotinib in non–small cell lung cancer. When given >5 days, PHT-427 caused no weight loss or change in blood chemistry. Thus, we report a novel PH domain binding inhibitor of PDPK1/Akt signaling with significant in vivo antitumor activity and minimal toxicity. Mol Cancer Ther; 9(3); 706–17
The Tumor Suppressor Maspin Mediates E2F1-Induced Sensitivity of Cancer Cells to Chemotherapy
Authors: Ben Shachar Berta , Feldstein Orit , Hacohen Dalia , Ginsberg Doron
Published: March 2010

The E2F1 transcription factor is a critical downstream target of the tumor suppressor RB. When activated, E2F1 can induce cell proliferation and/or apoptosis. In addition, E2F1 overexpression sensitizes cancer cells to chemotherapeutic drugs. In a screen for genes that are regulated synergistically by E2F1 and chemotherapy in cancer cells, we identified the proapoptotic tumor suppressor gene maspin (mammary serine protease inhibitor) as a novel E2F1-regulated gene. In line with being an E2F-regulated gene, maspin expression is inhibited by short hairpin RNA directed against E2F1 and increases upon activation of endogenous E2F. Furthermore, maspin mRNA and protein levels are elevated upon activation of exogenous E2F1. Importantly, we show that E2F1-mediated upregulation of maspin is enhanced by chemotherapeutic drugs, and inhibition of maspin expression significantly impairs the ability of E2F1 to promote chemotherapy-induced apoptosis. Summarily, our data indicate that maspin is an important effector of E2F1-induced chemosensitization. Mol Cancer Res; 8(3); 363–72
3-Phosphoinositide–Dependent Protein Kinase-1 Regulates Proliferation and Survival of Cancer Cells with an Activated Mitogen-Activated Protein Kinase Pathway
Authors: Lu Zhuomei , Cox-Hipkin Mary Ann , Windsor William T. , Boyapati Anita
Published: March 2010

Engagement of cell surface receptor tyrosine kinases by insulin and growth factors activates phosphatidylinositol 3-kinase (PI3K) and generates the second messenger, phosphatidylinositol 3,4,5-trisphosphate. This second messenger leads to the recruitment of 3-phosphoinositide–dependent protein kinase-1 (PDK1) to the proximal side of the plasma membrane, which results in the activation of AKT kinase. In addition, PDK1 can phosphorylate numerous other kinases, including p90RSK, a kinase downstream of mitogen-activated protein kinase (MAPK) that is important for cell proliferation and survival. Previous studies have shown that the loss of PDK1 sensitizes tumor cells to chemotherapeutic agents and radiation but have not focused on delineating the contribution of PDK1 to pathway-specific mutations associated with various cancers other than the PI3K/AKT pathway. In this study, we show that the reduction of PDK1 by RNAi in melanoma and colon cancer cell lines activated in the MAPK pathway results in significant cell growth inhibition and apoptosis. Furthermore, PDK1 reduction in tumor cells resulted in impaired PAK kinase signaling, altered actin polymerization, and reduced cell migration. These studies show that PDK1 plays a pivotal role in MAPK and PI3K signaling in tumor cells. Mol Cancer Res; 8(3); 421–32
Autotaxin Signaling via Lysophosphatidic Acid Receptors Contributes to Vascular Endothelial Growth Factor–Induced Endothelial Cell Migration
Authors: Ptaszynska Malgorzata M. , Pendrak Michael L. , Stracke Mary L. , Roberts David D.
Published: March 2010

Important roles for vascular endothelial growth factor (VEGF) and autotaxin (ATX) have been established for embryonic vasculogenesis and cancer progression. We examined whether these two angiogenic factors cooperate in regulation of endothelial cell migratory responses. VEGF stimulated expression of ATX and LPA1, a receptor for the ATX enzymatic product lysophosphatidic acid (LPA), in human umbilical vein endothelial cells. Knockdown of ATX expression significantly decreased mRNA levels for the receptors LPA1, LPA2, S1P1, S1P2, S1P3, and VEGFR2 and abolished cell migration to lysophosphatidylcholine, LPA, recombinant ATX, and VEGF. Migration to sphingosylphosphorylcholine and sphinogosine-1-phosphate was also reduced in ATX knockdown cells, whereas migration to serum remained unchanged. Furthermore, ATX knockdown decreased Akt2 mRNA levels, whereas LPA treatment strongly stimulated Akt2 expression. We propose that VEGF stimulates LPA production by inducing ATX expression. VEGF also increases LPA1 signaling, which in turn increases Akt2 expression. Akt2 is strongly associated with cancer progression, cellular migration, and promotion of epithelial-mesenchymal transition. These data show a role for ATX in maintaining expression of receptors required for VEGF and lysophospholipids to accelerate angiogenesis. Because VEGF and ATX are upregulated in many cancers, the regulatory mechanism proposed in these studies could apply to cancer-related angiogenesis and cancer progression. These data further suggest that ATX could be a prognostic factor or a target for therapeutic intervention in several cancers. Mol Cancer Res; 8(3); 309–21
GH/IGF-I Regulation in Obesity – Mechanisms and Practical Consequences in Children and Adults
Authors: Kreitschmann-Andermahr Ilonka , Suarez Pablo , Jennings Rachel , Evers Nina , Brabant Georg
Published: March 2010

Growth hormone (GH) secretion in children and adults is profoundly, but reversibly, suppressed in obesity. Since GH deficiency leads to increased fat mass, differentiation of both conditions remains challenging. Here we review the known and still speculative mechanisms underlying the inhibitory effects of obesity on GH secretion including peripheral factors like IGF-I and insulin, as well as central hypothalamic/pituitary modulators. We further discuss the basis of current testing for GH deficiency in obesity and the validity of the various provocative tests in overweight subjects.
Sex Hormones, Insulin Resistance and High-Density Lipoprotein Cholesterol Levels in Children
Authors: Agirbasli Mehmet , Agaoglu Nihat Bugra , Orak Nilay , Caglioz Hatice , Ocek Tuba , Karabağ Turgut , Baykan Oytun A.
Published: March 2010

Cardiovascular risk starts early in life; therefore, it is of interest to clarify the relation between puberty, sex hormones, insulin resistance and lipid levels in children. This is a cross sectional study of 365 school students (8–18 years of age). We analyzed the associations of sex hormones (testosterone, free androgen index, estradiol, free estradiol index) and sex hormone-binding globulin (SHBG) with insulin resistance and lipid levels. Analyses were performed in prepubertal versus adolescent girls and boys. Among prepubertal boys, estradiol was significantly associated with increased log homeostasis model assessment-estimated insulin resistance (HOMA-IR; B = 0.9, model R2 = 0.62, p < 0.001) and insulin levels (B = 0.8, model R2 = 0.58, p < 0.001). Testosterone was associated with increased high-density lipoprotein cholesterol (HDL-C) levels among prepubertal boys (B = 10, model R2 = 0.42, p = 0.04). Among adolescent girls, SHBG was significantly associated with decreased HOMA-IR (B = –0.8, model R2 = 0.34, p = 0.01) and insulin levels (B = –0.7, model R2 = 0.34, p = 0.01). SHBG was also related to increased HDL-C levels among prepubertal (B = 24, model R2 = 0.42, p = 0.047) and adolescent girls (B = 21, model R2 = 0.44, p = 0.002). In conclusion, sex hormone levels and SHBG have important effects on HDL-C and insulin resistance among children and adolescents.
Hyperprolactinemia: Different Clinical Expression in Childhood
Authors: Saranac L. , Zivanovic S. , Radovanovic Z. , Kostic G. , Markovic I. , Miljkovic P.
Published: March 2010

Background: Hyperprolactinemia is the most common disturbance in pituitary gland secretion. Functional diversity of prolactin action is responsible for different initial clinical expressions of hyperprolactinemia. Patients and Methods: We investigated causes of hyperprolactinemia in 11 children and adolescents (6 females and 5 males), aged from 1.5 to 17.5 years. Children with primary hypothyroidism, iatrogenic hyperprolactinemia and adolescents with polycystic ovaries were excluded. Results: Four patients had short stature or growth deceleration, the same number were clinically obese, 2 adolescent girls had secondary amenorrhea, 1 girl had premature thelarche and gynecomastia, and hypogonadism was the indication for the endocrinologic examination of two adolescent boys. Delayed pubertal development was present in both sexes. Hyperprolactinemia was also found in the youngest girl with multiple ovarian cysts. A very high prolactin (PRL) level was documented in the PRL profile of all patients (mean 2,553.00 ± 1,020.97 mU/l). MRI of the pituitary was indicated and revealed 4 microprolactinomas, one congenital hypophyseal cyst and one tumor of the hypothalamus. Dopamine agonist treatment was efficacious in almost all the patients. Conclusion: Hyperprolactinemic children expressed a wide variety of initial clinical presentations. The most common were growth and puberty disorders and obesity. PRL determination should be included in investigation protocols of obese and short stature children.
Thyroid Function in Obese Children and Adolescents
Authors: Marras Valeria , Casini Maria Rosaria , Pilia Sabrina , Carta Daniela , Civolani Patrizia , Porcu Manuela , Uccheddu Anna Paola , Loche Sandro
Published: March 2010

Objective: Obesity is frequently associated with modifications of thyroid size and function. We evaluated the prevalence of thyroid function abnormalities and the effects of puberty and weight loss in obese children and adolescents. Methods: We examined 468 obese children (255 girls and 213 boys aged 3.7–17.9 years) and 52 normal-weight age-matched children as controls. TSH, fT3, fT4, fasting serum insulin and glucose were measured at baseline. fT3, fT4 and TSH were also measured after 6 months of lifestyle intervention in a subset of 43 patients. Results: 109 obese children showed abnormal circulating thyroid hormone concentrations (84 had elevated fT3 levels, 15 elevated TSH, 6 elevated fT4, 3 elevated fT3 and TSH, and 1 elevated fT3, fT4 and TSH levels). Serum TSH and fT3 concentrations were positively correlated with BMI-SDS. The prevalence of patients with abnormal thyroid hormone concentrations was similar between sexes and between prepubertal and pubertal subjects. After 6 months of lifestyle intervention, thyroid hormone concentrations normalized in 27 of the patients with decreased BMI-SDS, and in 2 patients in whom BMI-SDS increased. Conclusions: In obese children, an increased fT3 concentration is the most frequent thyroid function abnormality. Serum fT3 and TSH correlate with BMI. Moderate weight loss frequently restores these abnormalities.
Magnetic Resonance Imaging and Pituitary Function in Children with Panhypopituitarism
Authors: Li Guimei , Shao Peng , Sun Xiaojun , Wang Qian , Zhang Lijuan
Published: March 2010

Background: To explore the relationship between magnetic resonance imaging (MRI) findings and multiple pituitary-target hormones in patients with panhypopituitarism or multiple pituitary hormone deficiency (MPHD). Methods: 125 patients with MPHD (102 boys, MPHD group) and 90 age-, sex- and Tanner stage-matched normal children (control group) were enrolled. 96 of the patients with MPHD underwent MRI scans of the hypothalamic-pituitary area. The patients were subdivided into five stages according to their MRI findings. The serum concentrations of GH, IGF-1, FT4, TSH, ACTH, cortisol, FSH, LH, prolactin, testosterone and estradiol were measured in patients and in controls. Results: MRI stage was significantly positively correlated with the number of pituitary hormone deficiencies (r = 0.9, p < 0.001). MRI stage was negatively correlated with peak GH, IGF-1, FT4, cortisol and anterior pituitary height (r = –0.43, –0.47, –0.67, –0.54, and –0.49, respectively, p < 0.01). Diabetes insipidus patients could be stratified according to their MRI stage; diabetes insipidus was found mainly in patients with absence of the posterior pituitary bright spot or small ectopic posterior pituitary bright spot on MRI. Conclusion: An abnormal MRI finding is evidence of MPHD and, correspondingly, there is a noteworthy correlation between MRI and pituitary function.
Prevalence of Tyrophagus putrescentiae Hypersensitivity in Subjects over 70 Years of Age in a Veterans’ Nursing Home in Taiwan
Authors: Liao En-Chih , Ho Chau-Mei , Tsai Jaw-Ji
Published: March 2010

Background: Domestic mites are present in house dust samples throughout the world. Reports have shown a high prevalence of Tyrophagus putrescentiae (Tp) sensitization in Europe and Asia, and its importance and clinical relevance in elderly subjects have grown rapidly. The main objective of this study was to investigate the prevalence of Tp sensitization in elderly subjects in a veterans’ nursing home using mite allergen extracts and recombinant allergens. Methods: A total of 199 subjects were enrolled in this study: 112 elderly subjects from a nursing home and 87 healthy young adults from the hospital staff as controls. The prevalence of Tp hypersensitivity was determined by specific IgE measurements and basophil histamine release. Immunoblotting with or without inhibition with Dermatophagoides pteronyssinus (Dp) was performed to identify the major allergens and species-specific allergen to Tp. Results: It was determined that 39.3% (44/112) of the elderly population were sensitized to Tp and 17.9% (20/112) to Tp alone. There was a significantly higher prevalence of Tp hypersensitivity in elderly subjects in comparison with the young adult population. In the age association study of Tp and Dp sensitization, the elderly subjects were more sensitized to Tp than to Dp (p = 0.02). Among the elderly subjects with chronic obstructive pulmonary disease (COPD) 45.8% (11/24) were Tp sensitive. The major allergens, Tyr p 2 and Tyr p 3, were identified with molecular weights of 16 kDa (53%) and 26 kDa (50%) as determined by ELISA and immunoblot inhibition analyses. Conclusion: The prevalence of Tp sensitization was higher in elderly subjects, especially in patients with COPD. The high percentage of IgE-binding components to the allergens Tyr p 2 and Tyr p 3 indicated that both allergens may play a role in the pathogenesis of IgE-mediated allergic diseases in elderly populations.
Amyloid Imaging in Early Detection of Alzheimer’s Disease
Authors: Nordberg Agneta
Published: March 2010

Amyloid imaging has provided evidence for early detection of amyloid (Aβ) load in prodromal Alzheimer’s disease (AD). Several amyloid tracers have been developed for studies with positron emission tomography (PET). Early detection of at-risk subjects will be important in the future for a successful treatment of AD. The high Aβ load in the brain measured by PET in patients with mild cognitive impairment that later will convert to AD suggests early, significant, ongoing pathological processes prior to cognitive impairment. PET Aβ imaging will also be used for discrimination of AD from other dementia disorders, as well for the evaluation of anti-Aβ drugs.
Inability of Plasma and Urine F2A-Isoprostane Levels to Differentiate Mild Cognitive Impairment from Alzheimer’s Disease
Authors: Mufson Elliott J. , Leurgans Sue
Published: March 2010

Background: Oxidative stress has been implicated in the pathogenesis of Alzheimer’s disease (AD). The pathobiological changes related to AD occur long before the overt clinical symptoms. The plasma lipid peroxidation enzyme F2-isoprostane has been suggested as a biomarker to detect the progression from mild cognitive impairment (MCI) to AD. Objective: To test whether plasma and urine F2-isoprostane was diagnostic for dementia in living people. Methods: Plasma and urine were collected from 222 Religious Orders Study participants with a clinical diagnosis of no cognitive impairment, MCI or AD at time of fluid collection. Isoprostane levels were determined using gas chromatography/mass spectroscopy. Results: Plasma and urine F2-isoprostane levels did not differ between the three clinical groups. Postmortem neuropathologic diagnosis of subjects who died during the course of the study was not associated with baseline blood or plasma F2-isoprostane levels. Conclusions: In living people, plasma or urine isoprostane levels were not sensitive enough to discriminate between individuals with a clinical diagnosis of no cognitive impairment, MCI or AD.
Increased CD44 Gene Expression in Lymphocytes Derived from Alzheimer Disease Patients
Authors: Uberti D. , Cenini G. , Bonini S.A. , Barcikowska M. , Styczynska M. , Szybinska A. , Memo M.
Published: March 2010

In this study, we demonstrated for the first time an increased CD44 gene expression in lymphocytes derived from Alzheimer’s disease (AD) patients in comparison with healthy subjects. CD44 is a surface antigen expressed by cells of the immune and central nervous system as well as in a variety of other tissues. Functioning as adhesion molecule, CD44 is furthermore involved in driving immune response into infected tissues, including the CNS. We also found that lymphocytes of the same patients expressed significant levels of unfolded p53 isoform, confirming what we already demonstrated in fibroblasts and lymphocytes derived from other cohorts of AD patients. A correlation between p53 and CD44 expression has been well demonstrated in cancer cells, suggesting that CD44 could be a target gene of mutant p53, or either mutant p53 could lack its ability to negatively regulate CD44 expression. The contemporaneous increased expression of unfolded p53 and CD44 in AD lymphocytes may suggest that these two molecules cross-talk together participating in peripheral immune response during the development of the disease.
Oophorectomy, Menopause, Estrogen, and Cognitive Aging: The Timing Hypothesis
Authors: Rocca Walter A. , Grossardt Brandon R. , Shuster Lynne T.
Published: March 2010

Background: The concept of neuroprotective effects of estrogen in women remains controversial. Objective: To explore the timing hypothesis in relation to cognitive aging and dementia. Methods: We reviewed existing literature, conducted some reanalyses, and combined results graphically. Results: Current evidence suggests that estrogen may have either protective effects or harmful effects on the brain depending on age, type of menopause (natural versus surgical), or stage of menopause. The comparison of women with ovarian conservation versus women who underwent bilateral oophorectomy provided evidence for a sizeable neuroprotective effect of estrogen in women in the premenopausal years (most commonly before age 50 years). Several case-control studies and cohort studies also showed a neuroprotective effect in women who received estrogen treatment in the early postmenopausal phase (most commonly at ages 50–60 years). However, recent clinical trials showed that women who initiated estrogen treatment in the late postmenopausal phase (ages 65–79 years) experienced an increased risk of dementia and cognitive decline. Conclusion: The neuroprotective effects of estrogen depend on age, type of menopause, and stage of menopause (timing hypothesis).
Common Variant in GRN Is a Genetic Risk Factor for Hippocampal Sclerosis in the Elderly
Authors: Dickson Dennis W. , Baker Matthew , Rademakers Rosa
Published: March 2010

Background: Hippocampal sclerosis (HpScl) is common in elderly subjects with dementia, either alone or accompanied by other pathologic processes. It is also found in >70% of frontotemporal lobar degeneration with TDP-43 immunoreactive inclusions (FTLD-TDP). TDP-43 inclusions are detected in >20% of Alzheimer disease (AD) and >70% of HpScl cases. The most common cause of FTLD-TDP is mutation in the progranulin gene (GRN). Recently, a common genetic variant in the 3′ untranslated region (3′UTR) of GRN (rs5848; c.*78C>T) located in a microRNA binding site regulated progranulin expression, and the T-allele was increased in FTLD-TDP compared to controls. Objective: The goal of this study was to determine if the 3′UTR variant in GRN was associated with TDP-43 immunoreactivity in AD with and without HpScl. Methods: 644 cases of pathologically confirmed AD, including 57 with HpScl, were screened for TDP-43 immunoreactivity and were genotyped at the GRN 3′UTR single-nucleotide polymorphism rs5848 using previously published methods. Results: There was a trend (p = 0.06) for TDP-43 immunoreactivity, but a very significant (p = 0.005) association of HpScl with the variant, with 72% of AD with HpScl carrying a T-allele, compared to 51% of AD without HpScl carrying a T-allele. Conclusion: The results suggest that a genetic variant in GRN leading to decreased levels of progranulin may be a risk factor for HpScl in AD, while its role in TDP-43 immunoreactivity in AD remains less certain.