bluuebunny/crossref_metadata_2025 huggingface dataset:
Gas6 deficiency prevents liver inflammation, steatohepatitis, and fibrosis in mice
Authors: Fourcot Agnès , Couchie Dominique , Chobert Marie-Noele , Zafrani Elie-Serge , Mavier Philippe , Laperche Yannick , Brouillet Arthur
Published: February 2011

The Gas6/Axl pathway has been increasingly implicated in regeneration and tissue repair and, recently, in the control of innate immunity. In liver, we have demonstrated that Gas6 and its receptor Axl are expressed in macrophages, progenitor cells, and myofibroblasts and that Gas6 deficiency reduced inflammation and myofibroblast activation, causing delayed liver repair in response to acute injury. All these data suggest a role of Gas6/Axl signaling in pathogenesis of chronic liver diseases. In the present study, we address the role of Gas6 in steatohepatitis and progression to liver fibrosis using Gas6-deficient mice fed a choline-deficient ethionine-supplemented diet (CDE) or receiving a chronic carbon tetrachloride (CCl4) treatment. Gas6 deficiency attenuated hepatic steatosis by limiting CDE-induced downregulation of genes involved in β-oxidation observed in wild-type animals. Moreover, Gas6-deficient mice displayed reduction of hepatic inflammation, revealed by limited F4/80-positive macrophage infiltration, decreased expression of IL-1β, TNF-α, lymphotoxin-β, and monocyte chemotactic protein-1, and attenuated hepatic progenitor cell response to CDE diet. Gas6 deficiency reduced CDE-induced fibrogenesis and hepatic myofibroblast activation and decreased expression of TGF-β and collagen 1 mRNAs. After chronic CCl4injury, Gas6-deficient mice also exhibited reduced liver fibrosis as a consequence of defective macrophage recruitment compared with wild-type animals. We conclude that improvement of steatohepatitis and fibrosis in Gas6−/−mice is linked to an inhibition of the inflammatory response that controls lipid metabolism and myofibroblast activation. This study highlights the deleterious effect of Gas6 in the progression of steatosis to steatohepatitis and fibrosis.
Regulation of JNK activity in the apoptotic response of intestinal epithelial cells
Authors: Ray Ramesh M. , Jin Shi , Bavaria Mitulkumar N. , Johnson Leonard R.
Published: February 2011

We have studied apoptosis of gastrointestinal epithelial cells by examining the receptor-mediated and DNA damage-induced pathways using TNF-α and camptothecin (CPT), respectively. TNF-α requires inhibition of antiapoptotic protein synthesis by cycloheximide (CHX). CHX also results in high levels of active JNK, which are necessary for TNF-induced apoptosis. While CPT induces apoptosis, the increase in JNK activity was not proportional to the degree of apoptosis. Thus the mechanism of activation of JNK and its role in apoptosis are unclear. We examined the course of JNK activation in response to a combination of TNF-α and CPT (TNF + CPT), which resulted in a three- to fourfold increase in apoptosis compared with CPT alone, indicating an amplification of apoptotic signaling pathways. TNF + CPT caused apoptosis by activating JNK, p38, and caspases-8, -9, and -3. TNF-α stimulated a transient phosphorylation of JNK1/2 and ERK1/2 at 15 min, which returned to basal by 60 min and remained low for 4 h. CPT increased JNK1/2 activity between 3 and 4 h. TNF + CPT caused a sustained and robust JNK1/2 and ERK1/2 phosphorylation by 2 h, which remained high at 4 h, suggesting involvement of MEKK4/7 and MEK1, respectively. When administered with TNF + CPT, SP-600125, a specific inhibitor of MEKK4/7, completely inhibited JNK1/2 and decreased apoptosis. However, administration of SP-600125 at 1 h after TNF + CPT failed to prevent JNK1/2 phosphorylation, and the protective effect of SP-600125 on apoptosis was abolished. These results indicate that the persistent activation of JNK might be due to inhibition of JNK-specific MAPK phosphatase 1 (MKP1). Small interfering RNA-mediated knockdown of MKP1 enhanced TNF + CPT-induced activity of JNK1/2 and caspases-9 and -3. Taken together, these results suggest that MKP1 activity determines the duration of JNK1/2 and p38 activation and, thereby, apoptosis in response to TNF + CPT.
Daily exercise vs. caloric restriction for prevention of nonalcoholic fatty liver disease in the OLETF rat model
Authors: Rector R. Scott , Uptergrove Grace M. , Morris E. Matthew , Borengasser Sarah J. , Laughlin M. Harold , Booth Frank W. , Thyfault John P. , Ibdah Jamal A.
Published: February 2011

The maintenance of normal body weight either through dietary modification or being habitually more physically active is associated with reduced incidence of nonalcoholic fatty liver disease (NAFLD). However, the means by which weight gain is prevented and potential mechanisms activated remain largely unstudied. Here, we sought to determine the effects of obesity prevention by daily exercise vs. caloric restriction on NAFLD in the hyperphagic, Otsuka Long-Evans Tokushima Fatty (OLETF) rat. At 4 wk of age, male OLETF rats ( n = 7–8/group) were randomized to groups of ad libitum fed, sedentary (OLETF-SED), voluntary wheel running exercise (OLETF-EX), or caloric restriction (OLETF-CR; 70% of SED) until 40 wk of age. Nonhyperphagic, control strain Long-Evans Tokushima Otsuka (LETO) rats were kept in sedentary cage conditions for the duration of the study (LETO-SED). Both daily exercise and caloric restriction prevented obesity and the development of type 2 diabetes observed in the OLETF-SED rats, with glucose tolerance during a glucose tolerance test improved to a greater extent in the OLETF-EX animals (30–50% lower glucose and insulin areas under the curve, P < 0.05). Both daily exercise and caloric restriction also prevented excess hepatic triglyceride and diacylglycerol accumulation ( P < 0.001), hepatocyte ballooning and nuclear displacement, and the increased perivenular fibrosis and collagen deposition that occurred in the obese OLETF-SED animals. However, despite similar hepatic phenotypes, OLETF-EX rats also exhibited increased hepatic mitochondrial fatty acid oxidation, enhanced oxidative enzyme function and protein content, and further suppression of hepatic de novo lipogenesis proteins compared with OLETF-CR. Prevention of obesity by either daily exercise or caloric restriction attenuates NAFLD development in OLETF rats. However, daily exercise may offer additional health benefits on glucose homeostasis and hepatic mitochondrial function compared with restricted diet alone.
Distinct neurophysiological profiles in irritable bowel syndrome
Authors: Arebi Naila , Bullas Dominic C. , Dukes George E. , Gurmany Salma , Hicks Kirsty J. , Kamm Michael A. , Hobson Anthony R.
Published: February 2011

The objective of this study was to determine whether cortical evoked potentials (CEPs) can define neurophysiological patterns in irritable bowel syndrome (IBS). In this prospective study of consecutive patients attending secondary and tertiary centers, patients with Rome II-defined IBS underwent rectal sensory and pain threshold (RST and RPT, respectively) testing with electrical stimulation on three separate visits. CEPs were collated for 75% pain thresholds, and anxiety [Spielberger State-Trait Anxiety Inventory (SSTAI)] questionnaires were completed. Subjects were 33 IBS patients (27 female, mean age 40.1 yr) and 21 healthy controls (14 female, mean age 31.4 yr). At visit 3, RPT was significantly lower [mean (95% CI)] in IBS patients than in control subjects: 58.2 mA (48.0–68.5) vs. 79.5 mA (69.3–89.6) ( P < 0.01). No significant differences were observed in CEP latencies and amplitudes between visits 1, 2, and 3 within each group, except P2 latency for controls ( P = 0.04) and N2 latency ( P = 0.04) and N2 amplitude ( P = 0.02) for IBS patients. Group comparisons showed significant differences in 3-day mean RPT, CEP amplitudes, and CEP latencies between IBS patients and controls. RPT <50 mA and P1 latency >106 ms were identified four IBS subgroups: 24% were hypersensitive, 12% were hypervigilant, 15% were hyposensitive, and 49% exhibited normal P1 latency and pain threshold. CEPs are reliable and reproducible measures of early sensory processing. Identification of four IBS neurophysiological patterns highlights its heterogeneous nature. These findings mark the first step toward personalized medicine in IBS, whereby therapy may be directed at the underlying physiological process.
Effect of deep inspiration avoidance on ventilation heterogeneity and airway responsiveness in healthy adults
Authors: Chapman David G. , Berend Norbert , King Gregory G. , Salome Cheryl M.
Published: February 2011

The mechanisms by which deep inspiration (DI) avoidance increases airway responsiveness in healthy subjects are not known. DI avoidance does not alter respiratory mechanics directly; however, computational modeling has predicted that DI avoidance would increase baseline ventilation heterogeneity. The aim was to determine if DI avoidance increased baseline ventilation heterogeneity and whether this correlated with the increase in airway responsiveness. Twelve healthy subjects had ventilation heterogeneity measured by multiple-breath nitrogen washout (MBNW) before and after 20 min of DI avoidance. This was followed by another 20-min period of DI avoidance before the inhalation of a single methacholine dose. The protocol was repeated on a separate day with the addition of five DIs at the end of each of the two periods of DI avoidance. Baseline ventilation heterogeneity in convection-dependent and diffusion-convection-dependent airways was calculated from MBNW. The response to methacholine was measured by the percent fall in forced expiratory volume in 1 s/forced vital capacity (FVC) (airway narrowing) and percent fall in FVC (airway closure). DI avoidance increased baseline diffusion-convection-dependent airways ( P = 0.02) but did not affect convection-dependent airways ( P = 0.9). DI avoidance increased both airway closure ( P = 0.002) and airway narrowing ( P = 0.02) during bronchial challenge. The increase in diffusion-convection-dependent airways due to DI avoidance did not correlate with the increase in either airway narrowing ( rs = 0.14) or airway closure ( rs = 0.12). These findings suggest that DI avoidance increases diffusion-convection-dependent ventilation heterogeneity that is not associated with the increase in airway responsiveness. We speculate that DI avoidance reduces surfactant release, which increases peripheral ventilation heterogeneity and also predisposes to peripheral airway closure.
Effect of obesity on respiratory mechanics during rest and exercise in COPD
Authors: Ora Josuel , Laveneziana Pierantonio , Wadell Karin , Preston Megan , Webb Katherine A. , O'Donnell Denis E.
Published: February 2011

The presence of obesity in COPD appears not to be a disadvantage with respect to dyspnea and weight-supported cycle exercise performance. We hypothesized that one explanation for this might be that the volume-reducing effects of obesity convey mechanical and respiratory muscle function advantages. Twelve obese chronic obstructive pulmonary disease (COPD) (OB) [forced expiratory volume in 1 s (FEV1) = 60%predicted; body mass index (BMI) = 32 ± 1 kg/m2; mean ± SD] and 12 age-matched, normal-weight COPD (NW) (FEV1= 59%predicted; BMI = 23 ± 2 kg/m2) subjects were compared at rest and during symptom-limited constant-work-rate exercise at 75% of their maximum. Measurements included pulmonary function tests, operating lung volumes, esophageal pressure, and gastric pressure. OB vs. NW had a reduced total lung capacity (109 vs. 124%predicted; P < 0.05) and resting end-expiratory lung volume (130 vs. 158%predicted; P < 0.05). At rest, there was no difference in respiratory muscle strength but OB had greater ( P < 0.05) static recoil and intra-abdominal pressures than NW. Peak ventilation, oxygen consumption, and exercise endurance times were similar in OB and NW. Pulmonary resistance fell ( P < 0.05) at the onset of exercise in OB but not in NW. Resting inspiratory capacity, dyspnea/ventilation plots, and the ratio of respiratory muscle effort to tidal volume displacement were similar, as was the dynamic performance of the respiratory muscles including the diaphragm. In conclusion, the lack of increase in dyspnea and exercise intolerance in OB vs. NW could not be attributed to improvement in respiratory muscle function. Potential contributory factors included alterations in the elastic properties of the lungs, raised intra-abdominal pressures, reduced lung hyperinflation, and preserved inspiratory capacity.
Asymmetrical action of the canine diaphragm after single-lung inflation
Authors: De Troyer André , Leduc Dimitri , Gevenois Pierre Alain , Cappello Matteo
Published: February 2011

Single-lung transplantation (SLT) in patients with emphysema leads to a cranial displacement of the diaphragm on the transplanted side and a shift of the mediastinum toward the transplanted lung. The objective of the present study was to assess the effect of unilateral lung inflation on the mechanics of the diaphragm. Two endotracheal tubes were inserted in the two main stem bronchi of six anesthetized dogs, and radiopaque markers were attached along muscle fibers in the midcostal region of the two halves of the diaphragm. The animals were then placed in a computed tomographic scanner, the left or the right lung was passively inflated, and the phrenic nerves were stimulated while the two endobronchial tubes were occluded. As lung volume increased, the fall in airway opening pressure (ΔPao) in the inflated lung during stimulation decreased markedly, whereas ΔPao in the noninflated lung decreased only moderately ( P < 0.001). Also, the two hemidiaphragms shortened both during relaxation and during phrenic stimulation, but the ipsilateral hemidiaphragm was consistently shorter than the contralateral hemidiaphragm. In addition, the radius of curvature of the ipsilateral hemidiaphragm during stimulation increased, whereas the radius of the contralateral hemidiaphragm remained unchanged. These observations indicate that 1) in the presence of unilateral lung inflation, the respiratory action of the diaphragm is asymmetric; and 2) this asymmetry is primarily determined by the differential effect of inflation on the length and curvature of the two halves of the muscle. These observations also imply that in patients with emphysema, SLT improves the action of the diaphragm on the transplanted side.
Role of endothelial progenitor cells in the beneficial effects of physical exercise on atherosclerosis and coronary artery disease
Authors: Lenk Karsten , Uhlemann Madlen , Schuler Gerhard , Adams Volker
Published: February 2011

In clinical trials as well as in several animal experiments it is evident that physical exercise is a powerful tool to positively influence the development and/or progression of atherosclerosis and coronary artery disease (CAD). The main target of physical exercise seems to be the maintenance of an intact endothelial cell layer. Since the discovery that endothelial progenitor cells (EPCs) are present in the circulation and the knowledge that exercise, either as a single exercise bout or an exercise training program, have the potency to mobilize EPCs from the bone marrow, the contribution of the EPCs for the preservation or repair of the endothelial cell layer is still under debate. Either the EPCs differentiate into mature endothelial cells, or they stimulate via a paracrine mechanism mature endothelial cells to proliferate. It is still unclear, if the exercise-induced mobilization of EPCs is casually related to the improvement of endothelial function. This review will discuss the role of endothelial progenitor cells in the beneficial effects of physical exercise on atherosclerosis and coronary artery disease.
Taxol Resistance in Breast Cancer Cells Is Mediated by the Hippo Pathway Component TAZ and Its Downstream Transcriptional TargetsCyr61andCTGF
Authors: Lai Dulcie , Ho King Ching , Hao Yawei , Yang Xiaolong
Published: February 2011

Taxol (paclitaxel) resistance represents a major challenge in breast cancer treatment. The TAZ (transcriptional co-activator with PDZ-binding motif) oncogene is a major component of the novel Hippo–LATS signaling pathway and a transcriptional coactivator that interacts with and activates multiple transcription factors to regulate various biological processes. Here, we report that elevated levels of TAZ found in human breast cancer cells are responsible for their resistance to Taxol. DNA microarray analysis identified the oncogenes Cyr61 and CTGF as downstream transcriptional targets of TAZ. Short hairpin RNA–mediated knockdown of both Cyr61 and CTGF reversed TAZ-induced Taxol resistance in breast cancer cells. Interaction of TAZ with the TEAD family of transcription factors was essential for TAZ to activate the Cyr61/CTGF promoters and to induce Taxol resistance. Our findings define the TAZ-TEAD-Cyr61/CTGF signaling pathway as an important modifier of the Taxol response in breast cancer cells, as well as highlighting it as a novel therapeutic target to treat drug-resistant breast cancers that arise commonly at advanced stages of disease. Cancer Res; 71(7); 2728–38. ©2011 AACR.
Vandetanib Restores Head and Neck Squamous Cell Carcinoma Cells' Sensitivity to Cisplatin and Radiation In Vivo and In Vitro
Authors: Sano Daisuke , Matsumoto Fumihiko , Valdecanas David R. , Zhao Mei , Molkentine David P. , Takahashi Yoko , Hanna Ehab Y. , Papadimitrakopoulou Vali , Heymach John , Milas Luka , Myers Jeffrey N.
Published: February 2011

Purpose: We investigated whether vandetanib, an inhibitor of the tyrosine kinase activities of vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor (EGFR), and rearranged during transfection (RET), could augment the antitumor activity of radiation with or without cisplatin in preclinical in vitro and in vivo models of human head and neck squamous cell carcinoma (HNSCC).

Experimental Design: OSC-19 and HN5 HNSCC cells that were cisplatin and radioresistant were treated with vandetanib, cisplatin, and radiation alone or in combination in vitro and in vivo using an orthotopic nude mouse model. Treatment effects were assessed using clonogenic survival assay, tumor volume, bioluminescence imaging, tumor growth delay, survival, microvessel density, tumor and endothelial cell apoptosis, and EGFR and Akt phosphorylation data.

Results: Vandetanib plus cisplatin radiosensitized HNSCC cells in vitro and in vivo. The combination treatment with vandetanib, cisplatin, and radiation was superior to the rest of treatments (including the double combinations) in antitumoral effects, prolonging survival, decreasing cervical lymph node metastases in vivo. It also increased both tumor and tumor-associated endothelial cell apoptosis and decreased microvessel density in vivo. An analysis of tumor growth delay data revealed that vandetanib plus cisplatin enhanced radioresponse in vivo. All vandetanib-containing treatments inhibited EGFR and Akt phosphorylation in vitro and in vivo.

Conclusion: The addition of vandetanib to combination therapy with cisplatin and radiation was able to effectively overcome cisplatin and radioresistance in in vitro and in vivo models of HNSCC. Further study of this regimen in clinical trials may be warranted. Clin Cancer Res; 17(7); 1815–27. ©2011 AACR.
DNA Repair Biomarker Profiling of Head and Neck Cancer: Ku80 Expression Predicts Locoregional Failure and Death following Radiotherapy
Authors: Moeller Benjamin J. , Yordy John S. , Williams Michelle D. , Giri Uma , Raju Uma , Molkentine David P. , Byers Lauren A. , Heymach John V. , Story Michael D. , Lee J. Jack , Sturgis Erich M , Weber Randal S. , Garden Adam S. , Ang K. Kian , Schwartz David L.
Published: February 2011

Purpose: Radiotherapy plays an integral role in the treatment of head and neck squamous cell carcinoma (HNSCC). Although proteins involved in DNA repair may predict HNSCC response to radiotherapy, none has been validated in this context. We examined whether differential expression of double-strand DNA break (DSB) repair proteins in HNSCC, the chief mediators of DNA repair following irradiation, predict for treatment outcomes.

Experimental Design: Archival HNSCC tumor specimens (n = 89) were assembled onto a tissue microarray and stained with antibodies raised against 38 biomarkers. The biomarker set was enriched for proteins involved in DSB repair, in addition to established mechanistic markers of radioresistance. Staining was correlated with treatment response and survival alongside established clinical and pathologic covariates. Results were validated in an independent intramural cohort (n = 34).

Results: Ku80, a key mediator of DSB repair, correlated most closely with clinical outcomes. Ku80 was overexpressed in half of all tumors, and its expression was independent of all other covariates examined. Ku80 overexpression was an independent predictor for both locoregional failure and mortality following radiotherapy (P < 0.01). The predictive power of Ku80 overexpression was confined largely to HPV-negative HNSCC, where it conferred a nine-fold greater risk of death at two years.

Conclusions: Ku80 overexpression is a common feature of HNSCC, and is a candidate DNA repair-related biomarker for radiation treatment failure and death, particularly in patients with high-risk HPV-negative disease. It is a promising, mechanistically rational biomarker to select individual HPV-negative HNSCC patients for strategies to intensify treatment. Clin Cancer Res; 17(7); 2035–43. ©2011 AACR.
Differential Response of Human and Mouse Dendritic Cells to VEGF Determines Interspecies Discrepancies in Tumor-Mediated Th1/Th2 Polarity Shift
Authors: Block Matthew S. , Nevala Wendy K. , Leontovich Alexey A. , Markovic Svetomir N.
Published: February 2011

Purpose: Metastatic cancer patients exhibit systemic dysregulation of immune polarity and are biased toward Th-2 immune responses. This is due, at least in part, to effects of VEGF on antigen presenting cell (APC) function. We therefore compared immune polarity changes in mouse models of cancer with those seen in human patients.

Experimental Design: We measured plasma levels of vascular growth factors and multiple cytokines via ELISA and multiplex analysis in mice with transplantable and spontaneous tumors. We compared immune cell subsets in naive and vaccinated mice with and without tumors. We assessed cytokine immune responses by multiplex analysis. Finally, we assessed gene expression and receptor surface expression in response to VEGF in mouse and human APCs.

Results: Although human patients have elevated plasma cytokines and altered immune polarity in response to antigen, mice have minimal immune abnormalities. Mouse VEGF does not mediate immune repolarization in vitro. Human but not mouse APCs upregulate VEGFR2 and downregulate interleukin (IL)-12β in response to VEGF.

Conclusions: Whereas humans with metastatic cancer demonstrate dysregulated immune polarity in response to excess plasma VEGF, tumor mice do not. This appears to be due to differences in APC responses to VEGF stimulation. Differential immune effects of VEGF may represent a key species difference in the context of translation of preclinical cancer immunotherapeutics into early clinical testing. Clin Cancer Res; 17(7); 1776–83. ©2011 AACR.
Abstract 100: Preclinical and clinical studies data consolidation and federation using an integrative data analysis system: SIMUSITETM
Authors: Vora Meena I.
Published: February 2011

One of the biggest challenges of the drug development process is to secure, access the experimental work and critical communications amongst the persons involved. These are the primary assets of any organization. These challenges stem from, (i) the data generated are collected mostly over a long period of time. (ii) the fast pace of development of new laboratory technologies requires the project management and underlying data structure constantly changing. (iii) outsourcing of the project work. (iv) multiple modes of communications among the peers.

Here we describe the data consolidation and federation module of BioPhase Systems’ SIMUSITETM (http://www.biophasesystems.com/simusite), a commercial software platform that allows users to integrate and analyze biological data from multiple experimental sources to uncover potentially valuable targets and guide the further drug development of therapeutic compounds. In order to ensure the accessibility to disparate knowledge bases, SIMUSITE has been architected using caBIGTM compatibility guidelines (http://cabig.nci.nih.gov). Though the software is built for the present needs of the industry, it is also designed to address the future challenges.

A case study depicting the migration of various types of data generated from multiple third party data analysis applications is presented spanning from pre-clinical to clinical level studies. It also demonstrates the analysis of the consolidated data further in the context of the public domain knowledge on the fly, thus providing the environment to consolidate data, updating the projects dynamically and allowing the communications amongst the peers.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 100.
Abstract 1005: Mesenchymal stem cells in breast cancer dormancy: Role of regulatory T cell induction
Authors: Patel Shyam A. , Rameshwar Pranela
Published: February 2011

Mesenchymal stem cells (MSCs) have been shown to support breast cancer growth. Since MSCs also increase the expansion of regulatory T cells (Tregs), we hypothesize that human MSCs protect breast cancer cells (BCCs) from immune clearance by recruitment and expansion of Tregs. MSCs suppressed the proliferation of PBMCs when the latter were exposed to γ-irradiated BCCs. Similarly, MSCs showed significant inhibition in the migration of PBMCs towards BCCs, despite the production of chemokines. MSCs also inhibited functional NK and CTL functions, which correlated with reduced numbers of CD8 and CD56 cells as compared to parallel cultures without MSCs. The reduced NK and CTL activities correlated with decrease in the total number of granzyme B-producing cells. To explain these findings, we compared Tregs in the presence or absence of MSCs and found increases with MSCs. The expansion of Tregs correlated with decreases in Th1 cytokines and increases in Th2 cytokines. MSC-derived TGF-β was mostly responsible for the increase in Tregs, based on knockdown studies. Together, these studies show increase in Tregs in co-cultures of PBMCs, BCCs and MSCs. The results could be partly explained by increase in Th2 type cytokines and MSC-generated TGF-β. These findings demonstrate immune protection by MSCs to BCCs. The reduced immune cell proliferation and recruitment mediated by MSCs has implications for treatment with chemotherapy.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1005.
Abstract 102: Mathematical models for growth of metastatic tumors
Authors: El-Kareh Ardith W. , Secomb Timothy W.
Published: February 2011

The mathematical form best describing the growth of a single tumor mass has been found to be any of several models including the power law, logistic or Gompertzian, depending on the particular clinical or experimental tumor considered. All these models exhibit monotonically decreasing growth rate over time; some plateau at some finite volume. However, the kinetics of growth of the total mass of a metastatic tumor remains a separate question with relevance for understanding survival time, optimal treatment, and the development of symptoms that arise from total tumor burden. Here, exact analytical solutions for total tumor burden are derived under the assumption that both the primary tumor and each individual metastatic lesion grow with power law kinetics. Solutions are also derived for the case of metastatic growth after removal of the primary tumor. Two cases are considered: one where the rate of metastasis formation from an individual lesion grows with power law kinetics, and one where this rate is independent of size. Surprisingly, the latter assumption, which is consistent with only a small subpopulation of cells having metastatic potential, proves entirely adequate to describe data of Iwata et al on the cumulative distribution of metastases of a human hepatocellular carcinoma. For both cases, as time progresses, the growth ultimately becomes exponential, regardless of whether or not the primary tumor has been excised. However, it is shown that for the range of parameters describing observed tumors, this exponential limit is not reached before the tumor burden becomes lethal. The growth does not, however, show the trend of decreasing rate with increasing volume exhibited by single lesions, and appears in fact approximately exponential over the range of clinical detectability. This provides an explanation for experimental data showing near exponential growth of plasma tumor markers such as carcinoembryonic antigen in patients followed for metastatic colorectal or medullary thyroid carcinoma. Using the model, it can be seen that neither the growth rate of individual lesions, nor the rate of metastasis formation by itself causes tumor lethality; rather it is the ratio of these two rates that determines whether a large number of metastases form before the primary tumor reaches detectable size. The models derived here are expected to have application to mathematical modeling of optimal treatment and tumor-immune system interactions.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 102.
Abstract 1022: PI3-kinase inhibition enhances ABT-737-induced apoptosis in colorectal cancer cell lines
Authors: Morrow Christopher J. , Hou Jian-Mei , Dive Caroline
Published: February 2011

The PI3-kinase signalling pathway is widely reported to promote survival, proliferation and migration. This pathway is up-regulated in several solid tumours by a host of different mechanisms, including PTEN deletion, RAS or PIK3CA mutation and aberrant activation of receptor tyrosine kinases. As such, inhibitors of PI3-kinase and its down-stream effectors are of great interest as tractable anti-cancer agents. The effect of PI3-kinase inhibition was investigated in colorectal cancer cell lines and demonstrated that, while PI3-kinase inhibition by itself did not cause cell death, it enhanced apoptosis induced by the BH3 mimetic ABT-737 (assessed by nuclear fragmentation, caspase 3 cleavage and phosphatidylserine exposure). Furthermore, ABT-737 and PI3-kinase inhibition caused increased level of Bak activating conformational change compared to ABT-737 alone, suggesting that the effect of PI3-kinase inhibition is up-stream of cytochrome C release. PI3-kinase inhibition did not alter the expression level of Bcl-2 family members, but co-immunoprecipitation revealed that it increased the amount of Bim bound to Bcl-xL. No change was seen in the binding of other BH3 only proteins or of Bax or Bak to ABT-737 targets Bcl-2 or Bcl-xL. ABT-737-induced apoptosis was independent of AKT and mTOR signalling as it was unaffected by the inhibitors AKTi1/2 and rapamycin respectively. A model is proposed whereby ABT-737 interrupts PI-3K inhibition-induced Bim/Bcl-xL complexes to promote apoptosis via Bax/Bak activation. Function testing experiments are underway to interrogate this model.

Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1022.
Abstract 1026: A non-apoptotic function for Mcl-1 as an activator of canonical Wnt signaling in keratinocytes
Authors: Sitailo Leonid , Sethupathi Periannan , Denning Mitchell F.
Published: February 2011

Mcl-1 is an anti-apoptotic Bcl-2 family member whose rapid down-regulation is required for UV apoptosis. We recently showed that not only is Mcl-1 a major human keratinocyte (KC) survival protein, but it is required for proper KC differentiation in organotypic culture, implicating a non-apoptotic function for Mcl-1 involved in regulating epidermal morphogenesis. To further explore the function of Mcl-1 in vivo, we generated and analyzed transgenic mice expressing human Mcl-1 under control of the keratin 5 (K5) promoter. K5-Mcl-1 transgenic mice had >2-fold increase in epidermal thickness (p<0.001), increased basal KC BrdU incorporation (∼2-fold) and altered expression of KC differentiation markers. Several K5-Mcl-1 mice developed benign follicular cysts. Since both proliferation and hair follicle morphogenesis are features of increased Wnt/β-catenin signaling, we examined components of the Wnt/β-catenin pathway. Epidermises from K5-Mcl-1 mice had elevated steady state β-catenin, P-GSK3β (Ser9, Ser21) and P-Akt (Ser473), consistent with Wnt pathway activation. To assess Wnt pathway in more detail, we over-expressed Mcl-1 in human KCs by retroviral transduction. Over-expression of Mcl-1, but not Bcl-2 or Bcl-xL, also induced KC proliferation (3.3-fold). Mcl-1 increased the levels of total and active β-catenin, c-Myc, P-GSK-3β, and P-Akt, as well as inducing TCF-4-dependent luciferase reporter activity (p<0.05) in keratinocytes. Q-RT-PCR analysis of Wnt pathway genes identified Disheveled-1, Frizzled-1 and Cyclin D3 as the most highly up-regulated genes common to both Mcl-1 transduced human KCs and K5-Mcl-1 mice. Mcl-1 truncation mutants encoding the N-terminal 208 and 103 amino acids, but lacking the BH domains, were generated and over expressed in KCs. Both Mcl-1 mutants induced 3H-thymidine incorporation (3.4- and 2.9-fold respectively), indicating that the mitogenic activity of Mcl-1 resides in its N-terminal region. Since β-catenin signaling is activated in cutaneous SCC and involved in stem cell maintenance, this non-apoptotic function of Mcl-1 represents a novel and potentially oncogenic activity in addition to its well characterized anti-apoptotic function.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1026.
Abstract 1031: Sphingolipid metabolism as a therapeutic target in chemotherapy resistant and hormone therapy resistant breast cancer
Authors: Gestaut Matthew M. , Antoon James W. , Ponnapakam Adharsh P. , J Liu , Burow Matthew E. , Foroozesh Maryam , Beckman Barbara S.
Published: February 2011

Endocrine- and chemo-resistance are major causes for failure of treatment in recurrent breast cancer. Normal apoptotic pathways targeted by chemotherapeutic agents become altered, diminishing their efficacy and increasing resistance mechanisms. The proapoptotic sphingolipid compound N-Octanoyl-D-erythro-sphingosine (C8-ceramide) mimics endogenous long chain ceramide and is a potent drug in endocrine-/chemo-resistant breast cancer cells. In this study, we examined basal expression levels of modifier enzymes for endogenous ceramide regulation across drug sensitive, chemoresistant and hormone therapy- resistant breast cancer cells lines. Differences were found among UDP-galactose ceramide galactosyltransferase, sphingosine kinase-1, and acid sphingomyelinase gene expression in: MCF-10A, MCF-7, MDA-MB-231 and MCF-7TN-R cell lines. Using C8-ceramide as the lead compound, 8 novel ceramide analogs were synthesized with either enol or amide backbone substitutions and tested for biological activity. The enol substitution was found to be the most potent, with (2S,3R,E)-2-((E)benzylideneamino)octadec-4-ene1,3-diol (Analog C) displaying the greatest reduction in proliferation. Analog B appeared to be the most potent cytotoxic drug in MCF-7 and MDA-MB-231 cell lines with IC50 values of 6.2uM and 3.0 uM respectively. In the cytotoxicity assay MCF-7TN-R cell line, Analog A appeared to be the most potent with an IC50 of 2.4uM. The clonogenic proliferation assay provided very different, yet promising results. Analog D had the lowest IC50 of 460nM in MDA-MB-231, Analog C had an IC50 of 100nM in MCF-7TN-R, and Analog A had an IC50 of 1.48uM in the MCF-7 breast cancer cell line. All of the IC50s for proliferation assays were at least an order of magnitude more potent than the control drug C8 (IC50 of 5uM). Due to the potency of these drugs, these results exemplify the potential of novel ceramide-targeted therapies in chemo-resistant and endocrine-resistant breast cancer cell lines.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1031.
Abstract 1043: Autophagy induces cytoprotection in cisplatin-treated lung cancer cells
Authors: Yang Sei-Hoon , Jang Hye Yeon , Jo Hyang Jeong , Lee Kang Kyoo , Moon Sun Rock , Kim Hak Ryul , Jeong Eun Taik , Lee Hyun Kyung , Park Soon A
Published: February 2011

Purpose: Most of lung cancer patients had received the systemic chemotherapy because they had diagnosed the advanced stage at presentation. Cislplatin-based chemotherapy is main regimen for advanced lung cancer. But serious adverse reaction (SAE) had occurred after chemotherapy. This is main reason for chemotherapy withdrawal. If we will use the reduced dose of cispaltin, cisplatin-based the chemotheray will be continued. To figure out whether the effect of low dose of cisplatin will be synergistically enhance by autophagy inhibiton, even though the reduced dose of cisplatin less effect for treatment response, We investigated that role of autophagy by 3-methyladenine, class III PI3kinase inhibitor in cisplatin-treated lung cancer cells. Methods: Lung cancer cells were incubated with normal media and treated the 5uM (LD20) and 20uM(LD50) of cislpaltin according to time dependent. We examined the sensitivity to low or high doses of cisplatin treatment using the MTT cell viability assay and compared apoptosis and autophagy by nuclear stianing, apoptotic or autophagic related proteins or autophagic vacuoles. autophagy is also displayed the development of acidic vascular organelles by acridine orange and the fluorescent expression of GFP-LC3 protein in the GFP-LC3 transfected cells. Result: Low dose of cisplatin-treated lung cancer cells is relatively less sensitive to cell death rather than high dose treated cells in a time-dependent manners. We didnot find out the nuclear fragmentation in lower dose even though detected its in high dose. PARP cleavages also were not detected in low dose of cisplatin exception 24H. We observed that massive vacuolization in the cytoplasm were seen at lower dose treated cells. Acridine orange stain-positive cells also were increased according to time dependent. We figured out that the autophagosome-incorporated LC3 II protein expression more increased in low dose treated cells (24H to 48H) in spite of no detection of LC3 II in high dose treated cells. The expression of GFP-LC3 were increased in 5uM treated cells by time-dependent manner. When 3-methyladenine, class III PI3kinase inhibitor, was pretreated in 5uM cisplatin-treated lung cancer cells, cell survival significantly were decreased. Conclusion: Autophagy induces cytoprotection in lower dose of cisplatin-treated lung cancer cells.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1043.
Abstract 1047: Circadian disruption induced by light at night upregulates PCNA expression in tissue-isolated human breast cancer xenografts in nude rats
Authors: Wu Jinghai , Dauchy Robert T. , Tirrell Paul C. , Wu Steven S. , Dauchy Erin M. , Blask David E. , Greene Michael W.
Published: February 2011

The circadian system and the cell cycle are two global regulatory systems in animals and humans. Previous studies have shown that disruption of either the circadian system or the cell cycle increases the risk of cancer in humans. However, the molecular mechanisms of circadian-mediated cell cycle dysregulation are not completely understood. Because proliferating cell nuclear antigen (PCNA) plays an essential role in DNA replication and cell cycle regulation, we studied the circadian regulation and disruption of PCNA in an in vivo animal model of human breast cancer. In tissue-isolated ER- MCF-7 human breast cancer xenografts grown in female nude rats exposed to a normal 12L:12D circadian condition, PCNA protein levels were maximal in the morning (2 h after lights on) but remained at very low levels throughout the rest of the 24 h period. To determine whether circadian disruption alters PCNA protein expression, xenograft-bearing nude rats were exposed to low intensity of light at night (LAN) (0.08 μW/cm2). PCNA protein was continuously expressed at a high level throughout the 24 h period in breast cancer xenografts growing in nude rats exposed to the LAN. Exposure of tumor-bearing rats to LAN also resulted in significantly accelerated growth of these xenografts. Moreover, several signaling cascades related to cell growth were examined. Daily rhythms of Akt and MAPK activation in the human breast cancer tumors were disrupted by LAN but did not track the changes in PCNA expression; however, PDK1 activation directly correlated with PCNA expression. Expression of PKCδ and PKCα, downstream targets of PDK1, was differentially elevated by LAN in xenografts in a manner consistent with their reported roles in cell proliferation. In contrast, LAN did not disrupt the rhythmic expression of either PCNA, PKCδ, or PKCα in the liver of the tumor-bearing rats. Expression of insulin-like growth factor 1 receptor (IGF-1R) protein, an upstream signaling molecule for PDK1, also correlated with the expression pattern of PDK1/PKC/PCNA in tumor-bearing rats exposed to LAN. Exposure of tumor-bearing rats to LAN disrupted the circadian rhythm of IGF-1R protein levels in the liver. Finally, circulating IGF-1 concentrations showed circadian disruption in LAN-exposed tumor-bearing nude rats. Thus, interruption of the IGF-1 signaling pathway may constitute a novel molecular mechanism of circadian regulated tumor growth. Taken together, our results suggest that LAN-induced disruption of circadian rhythms in cell signaling cascades accelerates tumor growth in vivo through continuous up-regulation of PCNA.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1047.
Abstract 1052: RNAi-mediated mutual regulation of FGF-2 and its antisense gene, NUDT6, in C6 glioma cells.
Authors: Baguma-Nibasheka Mark , Murphy Paul R.
Published: February 2011

Basic fibroblast growth factor (FGF-2) is a potent wide-spectrum antiapoptotic mitogen, and the dysregulation of its expression is associated with cell proliferation and immortalization in a wide variety of tumors. We have previously reported that FGF-2 and NUDT6, the product of its antisense gene, are co-localized and inversely expressed in C6 glioma cells, and that constitutive overexpression of NUDT6 suppresses cellular FGF-2 expression, nuclear translocation, and the resumption of cell cycles (Baguma-Nibasheka et al., Mol Cell Endocrinol, 267:127-136, 2007). For the current report, we investigated the role of the endogenous RNAi machinery in mediating the post-transcriptional effects of NUDT6 on FGF-2 expression. FGF-2 knockdown was accompanied by a significant (>3 fold) increase in NUDT6 mRNA, and vice versa. Similar converse effects were observed on the cognate protein levels, as assessed by confocal immunoflourescence, Western blotting, and flow cytometry, indicating that these two transcripts may be mutually regulatory. Remarkably, knockdown of either transcript reduced cell proliferation and inhibited S-phase re-entry following serum deprivation (Table 1), indicating that both FGF-2 and NUDT6 may be involved in the regulation of cell cycle progression. Supported by the CIHR and NSERC.Table 1.S-Phase Percentages1 of C6 Cells following Knockdown and G0 Arrest.Hours after Return to 10% FBS Medium0361224Control siRNA4.8 ± 0.516.8 ± 1.321.6 ± 1.822.4 ± 1.123.0 ± 1.5NUDT6 siRNA4.1 ± 0.510.6 ± 1.3*14.2 ± 1.6*16.7 ± 1.8*19.8 ± 0.8FGF-2 siRNA3.5 ± 0.55.9 ± 0.8*6.9 ± 1.2*11.2 ± 1.1*14.5 ± 1.0*1mean ± SEM. * = significantly different from control; p<0.05, n=3.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1052.
Abstract 1053: Modulation of Wnt/β-catenin signaling pathway by Cripto-1 in mouse embryonal carcinoma F9 cells
Authors: Nagaoka Tadahiro , Watanabe Kazuhide , Gonzales Monica , Castro Nadia , Rangel Maria-Cristina , Rollman Kelly , Rubin Jeffrey S. , Salomon David S. , Bianco Caterina
Published: February 2011

Cripto-1 is a membrane bound protein that belongs to the epidermal growth factor (EGF)-CFC (Cripto/FRL-1/cryptic) protein family. Cripto-1 is a co-receptor for the transforming growth factor-β related protein Nodal and together with Nodal induces Smad-2/3 phosphorylation through the serine-threonine kinase receptor ALK-4. Furthermore, Cripto-1 can also bind to Glypican-1, Caveolin-1, GRP78, TGFβ1, Activin, Notch and Wnt11 proteins. In the present study, 3xFLAG-tagged human Cripto-1 and HA-tagged Wnt proteins (Wnt-1, 3a, 5a and 11) were co-expressed in 293T cells and co-immunoprecipitation was carried out using anti-FLAG or anti-HA antibodies. All four Wnt proteins were found to bind to Cripto-1. We also evaluated whether Cripto-1 could bind to the Wnt receptor, Frizzled-8 cysteine rich domain and the Wnt co-receptor, LRP5 in 293T cells. LRP5 was found to co-immunoprecipitate with Cripto-1 in transiently transfected 293T cells, while no binding of Cripto-1 to Frizzled-8 was detected. Finally, we investigated the biological significance of the interaction between various Wnts and Cripto-1 using mouse embryonal carcinoma F9 cells that express high levels of endogenous Cripto-1 protein and Cripto-1 gene null F9 (F9 Cr-1-/-) cells. Interestingly, we found that F9 cells contained more stabilized cytoplasmic β-catenin than F9 Cr-1-/- cells after the cells were treated with Wnt3a protein. Super TOP-FLASH reporter assays also revealed a significant increase in luciferase activity in F9 cells compared to F9 Cr-1-/- cells following Wnt3a treatment. In conclusion, our results demonstrate that Cripto-1 can enhance the canonical Wnt/β-catenin signaling pathway in mouse embryonal carcinoma cells. Therefore, modulation of the canonical Wnt/β-catenin pathway by Cripto-1 might perform an important role in embryonic stem cells and embryonal carcinoma cells that are expressing high levels of Cripto-1.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1053.