bluuebunny/crossref_metadata_2025 huggingface dataset:
Experimental Study on Aerodynamic Heating Induced by Dual Injections into Hypersonic Cross Flow
Authors: Taguchi Masato , Mori Koichi , Nakamura Yoshiaki
Published: May 2017

In this study, the distribution of surface heat transfer induced by dual side-jets injected into a hypersonic flow has been visualized using a temperature sensitive paint. The experiments were performed in both tandem and parallel injector arrangements, and the spacing between the injection holes was taken as a parameter in each arrangement. As a result, the aerodynamic heating in the separated region of the boundary layer and in the horseshoe vortex was clearly visualized. In the tandem arrangements, heat transfer remarkably increased immediately upstream of the front injector. The distributions and the intensity of surface heat transfer were similar to those caused by the single injection. On the other hand, in the parallel arrangements, the extent of the separation nearly doubled, and the maximum heat flux decreased to less than half of that from the single injection. The global distribution of heat transfer varied significantly as the injector spacing was changed. When the injectors were positioned with a large spacing, the interaction between the side-jets was relatively lowered, and thus distribution, as for the single injector, was induced around each injection hole individually. In contrast, with a short spacing, the dual injection behaved as a single obstacle. The most effective reduction of maximum heat flux was achieved with an intermediate injector spacing.
Monte Carlo Simulation for Polychromatic X-Ray Fluorescence Computed Tomography with Sheet-Beam Geometry
Authors: Jiang Shanghai , He Peng , Deng Luzhen , Chen Mianyi , Wei Biao
Published: May 2017

X-ray fluorescence computed tomography (XFCT) based on sheet beam can save a huge amount of time to obtain a whole set of projections using synchrotron. However, it is clearly unpractical for most biomedical research laboratories. In this paper, polychromatic X-ray fluorescence computed tomography with sheet-beam geometry is tested by Monte Carlo simulation. First, two phantoms (A and B) filled with PMMA are used to simulate imaging process through GEANT 4. Phantom A contains several GNP-loaded regions with the same size (10 mm) in height and diameter but different Au weight concentration ranging from 0.3% to 1.8%. Phantom B contains twelve GNP-loaded regions with the same Au weight concentration (1.6%) but different diameter ranging from 1 mm to 9 mm. Second, discretized presentation of imaging model is established to reconstruct more accurate XFCT images. Third, XFCT images of phantoms A and B are reconstructed by filter back-projection (FBP) and maximum likelihood expectation maximization (MLEM) with and without correction, respectively. Contrast-to-noise ratio (CNR) is calculated to evaluate all the reconstructed images. Our results show that it is feasible for sheet-beam XFCT system based on polychromatic X-ray source and the discretized imaging model can be used to reconstruct more accurate images.
Analysing the Influence of Health Insurance Status on Peoples’ Health Seeking Behaviour in Rural Ghana
Authors: Osei Asibey Benedict , Agyemang Seth
Published: May 2017

This paper examines the influence of health insurance status on healthcare use in rural Ghana using 286 sampled respondents from four rural communities in the Bekwai Municipality. Data were obtained using structured interview and Pearson’s Chi square and bivariate regressions were used to analyse data. The results show low healthcare utilization among study participants, with most respondents having irregular use (43.5%) or rare use (43.3%). Respondents with health insurance utilized healthcare more than those without health insurance, the results being statistically significant (df = 4; n = 283, p = 0.000). The bivariate analysis revealed that health insurance status has a positive and significant influence on utilization (β = 1.284; p value = 0.000). The study recommends promotion and improvement of services of the National Health Insurance Scheme as effective strategy to improve healthcare consumption by the rural people. The expansion of health insurance services to all sections of the population is also recommended.
Abstract A02: pRb-loss causes widespread changes to the transcriptome and proteome of cells
Authors: Miles Wayne O.
Published: May 2017

Loss of the Retinoblastoma 1, pRb, tumor-suppressor gene is widespread in tumor cells and causes de-regulation of the E2F transcription factors. Aberrant E2F activity results in the over expression of genes required for proliferation. To determine how pRb-loss changes cells, we depleted pRb from RPE cells using shRNAs and measured the effect on the transcriptome and proteome using RNA-sequencing and quantitative Mass Spectrometry. These approaches produced a number of unexpected findings including; (A) many E2F target genes are transcribed but poorly translated, (B) pRb-loss induces a strong interferon response, and (C) pRb-deficiency increases the protein levels of the extracellular matrix components. In addition, our results support previous reports linking pRb to mitochondrial activity and metabolic reprogramming. The changes to the transcriptome and proteome are extensive and complex and we are currently conducting an in-depth analysis of these results however our preliminary analysis suggests that loss of the pRb tumor-suppressor gene causes widespread and previously unappreciated changes in the transcriptome and proteome of cells. To begin to understand the mechanisms regulating these changes in translation potential, we have begun assessing the post-transcriptional mechanisms controlling the levels of the E2F-target genes. This group of genes is induced upon pRb-loss however no associated increase in protein levels is detected. To identify the mechanisms controlling the translation potential of this collection of genes, we search for enriched motifs of post-transcriptional regulators in these mRNAs. This analysis found a strong enrichment for the Pumilio (PUM) RNA-binding protein. RNA-immunoprecipitation experiments confirm that the levels of E2F target genes bound by PUM increase upon pRb-loss. To assay how PUM levels regulate the protein levels of the E2F target genes, we depleted PUM1 or PUM2 using siRNAs and conducted quantitative Mass Spectrometry. From this analysis, we find a strong increase in the levels of some E2F target genes upon PUM and pRb-loss. Collectively, these results are providing new insights into the proteomic changes induced after pRb-loss and is highlighting some of the post-transcriptional mechanisms buffering these effects.

Citation Format: Wayne O. Miles. pRb-loss causes widespread changes to the transcriptome and proteome of cells. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A02.
Abstract A03: FGF-WNT cooperativity and the role of lncRNAs in translational regulation in breast cancer
Authors: Nguyen Tuan M. , Kabotyanski Elena B. , Reineke Lucas C. , Mo Qianxing , Zhang Peng , Zhang Xiang , Chen Yiwen , Neilson Joel , Lloyd Richard E. , Rosen Jeffrey M.
Published: May 2017

The purpose of this study is to understand translational mechanisms underlying the cooperativity between FGF and WNT signaling in cancer progression. FGF and WNT signaling, crucial pathways in mammary stem cell self-renewal, are frequently deregulated in human cancer. We previously showed that acute activation of FGF signaling in the mammary gland of pubertal mice with WNT hyperactivation dramatically accelerates cancer progression. FGF-WNT-hyperactive tumor cells exhibit enhanced activation of translational machinery. Given the potential involvement of translational regulation in FGF-WNT induced tumorigenesis, we employed ribosome profiling to identify selectively translated and ribosome associated RNAs induced by acute FGF activation in vivo. Many genes associated with RNA processing and transport were translationally upregulated. Interestingly, the most translationally upregulated transcript was Malat1, originally thought to be a nuclear-restricted long noncoding RNA (lncRNA) that regulates transcription of cancer-associated genes. Along with Malat1, many lncRNAs were associated with ribosomes in FGF-WNT tumors. Malat1's association with polysomes upon acute FGF activation was confirmed by direct polysome analysis. We also demonstrated that Malat1 transcripts are transported to the cytoplasm during G2/M transition, implicating that Malat1 may be translated into small novel peptides or involved in translation regulation during this particular phase of cell cycle. Additionally, there is evidence that Malat1 is a direct downstream target of WNT signaling. Our findings indicate that FGF activation potentially increases the translation efficiency of WNT-target oncogenes including lncRNAs like Malat1, unraveling a novel mechanism of crosstalk between lncRNAs and translational regulation in cancer progression.

Citation Format: Tuan M. Nguyen, Elena B. Kabotyanski, Lucas C. Reineke, Qianxing Mo, Peng Zhang, Xiang Zhang, Yiwen Chen, Joel Neilson, Richard E. Lloyd, Jeffrey M. Rosen. FGF-WNT cooperativity and the role of lncRNAs in translational regulation in breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A03.
Abstract A14: Proteomic analysis of paired malignant and non-malignant tissues from patients with NSCLC adenocarcinoma identified changes in translation initiation factors potentially important in oncogenesis
Authors: Miyamoto Suzanne , Fahrmann Johannes F. , Grapov Dmitry , Phinney Brett , Pass Harvey
Published: May 2017

An important aspect of the control of mRNA translation into protein in mammalian cells is the initiation process, which involves the activities of multiple eukaryotic translation initiation factors or eIFs. Genetic analyses of eIFs in yeast (S. cerevisiae) have defined the eIFs necessary for the basic translation of mRNAs into proteins, but additional subunits found in mammalian cells have not been as well defined in normal cells so how the activities and functions of eIFs may be dysregulated in cancers such as lung cancer are still being determined. Lung cancer causes the highest cancer mortality in men and women in the United States. Lung cancer, mostly non-small cell (NSCLC) adenocarcinoma is responsible for about 13% of all new cancer cases and 26% of all cancer deaths. We undertook a proteomic analysis of lung cancer by analyzing 39 pairs of malignant and non-malignant lung tissues obtained from patients with early stage NSCLC adenocarcinoma using trypsin digestion and tandem MS/MS. Examination of eIFs in these tissues showed significant proteomic differences with significant increases in eIFs, especially in eIF2A, eIF2B, 1 alpha, and eIF2B, 5 episilon (p-values < 0.05). Smaller, but significant increased fold changes were also observed in eIF3B, eIF3G, eIF3J, eIF4G1, eIF4E eIF4A1 and eIF4H. Increased protein levels of EIF2AK2, the interferon induced eIF2A protein kinase was also detected. The eIF2alpha exchange rate may be an important aspect of tumorigenesis in lung cancer tissues with the increased exchange of GTP for GDP in eIF2A, hence the large increases in eIF2B subunits. Increases in eIF3 subunits, especially eIF3j, as well as increases in eIF4E and eIF4G1 correspond to increased protein synthesis rates and cellular proliferation. These early results need further investigation and related functional analysis to determine if the changes in eIFs correspond to important activities in the tumor cells or surrounding microenvironment and have mechanistic consequences in the growth and progression of lung cancer tumors.

Citation Format: Suzanne Miyamoto, Johannes F. Fahrmann, Dmitry Grapov, Brett Phinney, Harvey Pass. Proteomic analysis of paired malignant and non-malignant tissues from patients with NSCLC adenocarcinoma identified changes in translation initiation factors potentially important in oncogenesis. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A14.
Abstract A24: Translation control of tumor metastasis via FSTL1 binding with SPP1/OPN to modulated cytoskeleton remodeling
Authors: Chiou Jean , Lin Yuan-Feng , Hsiao Michael
Published: May 2017

Follistatin-like protein 1 (FSTL1) plays a critical role in lung organogenesis. However, the prognostic significance and functional consequence of FSTL1 downregulation remains unclear in lung cancer. Here we show that the reduced levels of FSTL1 are widely detected in tumors compared to normal tissues and reflect a poor clinical outcome in non-small cell lung cancer, especially lung adenocarcinoma. Moreover, we found that FSTL1 expression negatively correlates with the metastatic potential of lung cancer cells in vitro and in vivo. Whereas the antibody-based neutralization of extracellular FSTL1 enhances the cellular migration/invasion ability, the inclusion of recombinant FSTL1 protein diminishes the metastatic capacity of lung cancer cells in vitro and in vivo. Notably, the administration of FSTL1 was capable of effectively preventing the metastatic progression of lung cancer cells in an orthotropic animal model. The in vitro protein-protein interaction (PPI) assay demonstrated that FSTL1 directly binds to the pro-form of secreted phosphoprotein 1 (SPP1), also named osteopontin (OPN), and thereby restrains the proteolytic activation of SPP1/OPN, which leads to the inactivation of integrin/CD44-associated signaling cascades and actin cytoskeleton. Runx2 and osterix transcription factors are required for the expression of SPP1/OPN. Thus, FSTL1 compromised the SPP1/OPN related translation control activity through PPI mechanism to reverse the phenotype in lung cancer. The signature of combining low-level FSTL1 with high-level SPP1 predicts a worse prognosis in lung cancer patients. This study is the first to document the PPI between FSTL1 and SPP1/OPN and our findings provide a novel and effective strategy to combat SPP1/OPN-driven metastatic cancers with FSTL1 downregulation.

Citation Format: Jean Chiou, Yuan-Feng Lin, Michael Hsiao. Translation control of tumor metastasis via FSTL1 binding with SPP1/OPN to modulated cytoskeleton remodeling. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A24.
Abstract A28: Oxygen-dependent translatome remodeling is controlled by eIF2α dephosphorylation
Authors: Ho J.J. David , Balukoff Nathan C. , Cervantes Grissel , Rosa Ayalivis De La , Lee Stephen
Published: May 2017

Introduction: Eukaryotic translation initiation factor 2α (eIF2α) is a core component of the cellular translation machinery. Alterations in eIF2α phosphorylation constitute a key adaptation during a variety of physiological stresses, including oxygen deprivation (hypoxia). We recently found that cancer cells respond to hypoxia through the systemic reprogramming of cap-dependent mRNA translation efficiencies by switching to the hypoxic eIF4F, eIF4FH. In the present study, we sought to elucidate the role(s) of eIF2α phosphorylation and dephosphorylation in this translatome remodeling process. In particular, the growth arrest and DNA damage-inducible protein GADD34 has been reported as an adaptive, stress-activated mediator of eIF2α dephosphorylation. We aimed to determine the role of GADD34 in the cellular hypoxic response.

Findings: Our results indicate that hypoxia-induced eIF2α phosphorylation is a transient response with corresponding effects on translation efficiencies. Using next-generation mRNA sequencing (mRNA-seq), we reveal the dynamic profile of the translatome remodeling process during acute and chronic hypoxia. Our findings demonstrate that GADD34-mediated eIF2α dephosphorylation is required for hypoxic protein synthesis. GADD34 silencing results in high levels of eIF2α phosphorylation and severe global translational inhibition. Notably, GADD34 regulates the translation of hypoxia-inducible proteins in a hypoxia-inducible factor 2α (HIF-2α)-dependent manner. Finally, high throughput mass spectrometry (MS) analysis reveals several potential hypoxia-regulated GADD34 post-translational modifications (PTMs). Efforts are underway to validate and determine the effect(s) of these PTMs on GADD34 protein stability and/or activity.

Conclusion: We demonstrate that GADD34-mediated eIF2α dephosphorylation regulates oxygen-dependent translatome reprogramming in cancer cells. This pathway represents an exciting potential target for cancer therapeutics.

Citation Format: J.J. David Ho, Nathan C. Balukoff, Grissel Cervantes, Ayalivis De La Rosa, Stephen Lee. Oxygen-dependent translatome remodeling is controlled by eIF2α dephosphorylation. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A28.
Abstract A45: Targeting eIF4A dependent translation as therapeutics in pancreatic cancer
Authors: Singh Kamini , Lecomte Nicolas , Stark Stefan , Burčul Antonija , Olivera Grbovic-Huezo , Grimont Adrien , Viale Agnes , Mohan Prathibha , Jiang Man , Destanchia Elisa , Gokce Askan , Rätsch Gunnar , Leach Steve D. , Wendel Hans-Guido
Published: May 2017

RNA translation is activated in aggressive pancreatic cancer and at the same time is also refractory to mTOR inhibition. We have used a translation inhibitor for eIF4A, RNA helicase that is downstream of mTOR signaling and can be functionally targeted in pancreatic cancer. We establish that Silvestrol and its analog CR-31B showed potent anti-tumor activity in pancreatic cancer cell lines in vitro and in vivo. Silvestrol/CR-31B reduced pancreatic cancer cells and organoids growth derived from mouse model of pancreatic cancer and human patient samples in vitro. Further we identify the genome wide translational targets of Silvestrol in pancreatic cancer cell line that lacks response to mTOR signaling through loss of EIF4EBP1. Silvestrol down regulate translation of many key oncogenes and others cellular factors involved in oncogenic signaling specific to pancreatic cancer. Silvestrol targets were also enriched for G-quadruplex structure in their 5' UTR. With this study we establish a new mechanism of targeting pancreatic cancer cells through translation inhibition and identify newer proteins as therapeutic targets that are regulated independent of mTOR signaling.

Citation Format: Kamini Singh, Nicolas Lecomte, Stefan Stark, Antonija Burčul, Grbovic-Huezo Olivera, Adrien Grimont, Agnes Viale, Prathibha Mohan, Man Jiang, Elisa Destanchia, Askan Gokce, Gunnar Rätsch, Steve D. Leach, Hans-Guido Wendel. Targeting eIF4A dependent translation as therapeutics in pancreatic cancer. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr A45.
Abstract B03: A whole genome screening platform to identify genes that overcome the poor translation of KRAS
Authors: Peterson Jackson J. , Kaltenbrun Erin , Counter Christopher
Published: May 2017

We discovered that KRAS mRNA is highly enriched in rare codons, which limited translation of the encoded KRAS protein. Accumulating evidence suggests that there is a selective pressure during tumorigenesis to overcome the poor translation of KRAS imposed by rare codons to produce more oncogenic protein and promote more malignant phenotypes. To identify how cancer cells achieve this feat, we are screening whole genome gain- and loss-of-function libraries for genes capable of increasing the translation of a rare-codon enriched fluorescent reporter. More specifically, we have created a reporter cell line encoding a rare-codon enriched GFP and a common-codon enriched mCherry protein. Normalizing to mCherry expression, we further demonstrate that FACS can effectively isolate cells expressing a common-codon enriched GFP from those expressing the rare codon counterpart. Given this, the reporter line was stably infected with a CRISPR library targeting 19,050 genes and sorted by FACS for those expressing high levels of GFP, with these cells now being subjected to deep sequencing. A whole genome ORF library is being screened in an identical fashion. In the future, we will rescreen candidate CRISPRs or ORFs identified from these screens, and those that reproducibly increase the expression of the rare-codon enriched reporter will be analyzed further, especially with regards to the underlying mechanism and expression in cancer cells.

Citation Format: Jackson J. Peterson, Erin Kaltenbrun, Christopher Counter. A whole genome screening platform to identify genes that overcome the poor translation of KRAS. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B03.
Abstract B09: hnRNPA1 is a regulator of UNR IRES activity
Authors: Lampe Sebastian , Brauß Thilo , Kunze Michael , Scholz Anica , Winslow Sofia , Brüne Bernhard , Schmid Tobias
Published: May 2017

Alternative translation initiation via internal ribosome entry sites (IRESs) allows for sustained expression of specific proteins under conditions, such as stress, where global translation is inhibited. As cells in tumors are constantly facing stress conditions, e.g. hypoxia or nutrient deprivation, it is not surprising that mRNAs encoding for oncogenes appear to be enriched in IRESs. IRES-dependent translation in eukaryotes commonly involves certain RNA-binding proteins, the so-called IRES trans-acting factors (ITAFs), that can directly interact with the IRESs to facilitate translation initiation. Upstream of N-Ras (UNR) is such an ITAF that can regulate the IRES activity of several cellular and viral IRESs. It is known that its 5' untranslated region (5' UTR) also contains an IRES that is regulated by polypyrimidine-tract binding protein (PTB), heterogeneous nuclear ribonucleoprotein (hnRNP) C1/C2 and UNR itself. Prediction analyses indicated that hnRNPA1 might bind to the 5' UTR of UNR as well. hnRNPA1 was previously already shown to serve as an ITAF in the regulation of the IRES activities of numerous mRNAs including egr2 and sST2. The aims of this project were to determine the impact of hnRNPA1 on the IRES activity of UNR. To test, if hnRNPA1 interacts with the 5' UTR of UNR, as predicted, we employed RNA affinity chromatography. We found that hnRNPA1 indeed strongly bound to the UNR 5' UTR. To assess, if hnRNPA1 consequently affects UNR IRES activity, we overexpressed hnRNPA1. Overexpression of hnRNPA1 markedly increased UNR IRES activity. hnRNPA1 overexpression further induced total UNR protein expression, which indicates that elevated UNR IRES activity results in enhanced translation. With respect to the exact interaction sites, hnRNPA1 binding was predicted to occur at overlapping sites to the previously published PTB binding sites. Deletion of the hnRNPA1 binding sites not only decreased the UNR IRES activity, it further rendered it insensitive to elevated hnRNPA1 levels. Taken together, we found that the 5' UTR of UNR contains specific hnRNPA1 binding sites and that binding of hnRNPA1 at these sites enhances the UNR IRES activity. Our findings therefore add a new piece to the complex puzzle of UNR regulating ITAFs. Having established hnRNPA1 as a new regulator of UNR IRES activity, might further put hnRNPA1 forward as an interesting target to regulate UNR expression.

Citation Format: Sebastian Lampe, Thilo Brauß, Michael Kunze, Anica Scholz, Sofia Winslow, Bernhard Brüne, Tobias Schmid. hnRNPA1 is a regulator of UNR IRES activity. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B09.
Abstract B11: Oncogenic KRAS regulates 4E-BP1, a repressor of cap-dependent translation, independently of growth factor activity
Authors: Silva Jillian M. , Bagni Rachel K. , Ruggero Davide , McCormick Frank
Published: May 2017

Oncogenic mutations in K-Ras often occur at high frequencies in human cancer resulting in the sustained activation of the ERK1/2 mitogen-activated protein kinase (MAPK) signaling pathway. However, the unique dependencies on upstream or downstream oncogenic signaling amongst the mutant K-Ras proteins remains elusive and often masked by the remaining wild-type allele, other Ras isoforms, or additional secondary genetic alterations. Thus, we employed an isogenic mouse embryonic fibroblast (MEFs) system devoid of H-, N-, and K-Ras alleles and reconstituted with a single Ras isoform to examine the dependencies of growth factors on K-Ras mediated control of translational regulation. Although oncogenic K-Ras G12D and G12V mutant MEF lines proliferated at twice the rate of K-Ras4b wild-type MEF cells, growth factor deprivation led to a cytostatic effect on the proliferation of all MEF lines. Analysis of signaling downstream of K-Ras revealed that phosphorylation of 4E-BP1, eIF4E, and ERK1/2 occurred in a growth factor-independent manner, which stood in contrast to the substantive effects of growth factor inhibition on AKT, p70S6K, and ribosomal protein S6 phosphorylation. Moreover, growth factor deprivation resulted in a marginal decrease of global protein synthesis with negligible effects on cap-dependent translation initiation in all K-Ras MEF cell lines. Taken together, these data suggest that oncogenic K-Ras signaling regulates 4E-BP1 phosphorylation independently of growth factor and mTORC1/2 effects.

Citation Format: Jillian M. Silva, Rachel K. Bagni, Davide Ruggero, Frank McCormick. Oncogenic KRAS regulates 4E-BP1, a repressor of cap-dependent translation, independently of growth factor activity. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B11.
Abstract B13: EGF/Ras/Erk signaling controls growth and proliferation through regulation of tRNA synthesis
Authors: Sriskanthadevan-Pirahas Shrivani , Grewal Savraj S.
Published: May 2017

Ras signaling promotes growth and proliferation in many tissues throughout animal development. An important challenge is to identify how the Ras-Erk pathway alters cellular metabolism to drive growth. Here we report on the control of tRNA synthesis as growth effector of EGF/Ras/Erk signaling in Drosophila. I find that overexpression of oncogenic Ras (RasV12) leads to increased mRNA translation and protein content in Drosophila S2 cells, suggesting that Ras may promote growth through enhanced protein synthesis. The conventional view is that the Ras pathway functions by controlling translation initiation factor activity. However I have identified an alternate mechanism involving control of tRNA synthesis. My data suggest that overexpression of RasV12 or the activated versions of EGFR and the Raf1 in wing imaginal discs increases tRNA synthesis. Similarly, expression of RasV12 in S2 cells increases tRNA levels, while blocking Ras/Erk signaling using the MEK inhibitor, U0126 or RNAi reduces tRNA synthesis. We previously identified the RNA polymerase III (Pol III) factor, Brf, as regulator of cell and tissue growth in Drosophila. Here we show that knockdown of either Brf blocks the effects of Ras signaling on growth and proliferation in larval wing imaginal discs, adult midgut progenitor cells and adult intestinal stem cells. Several transcription factors have been shown to link Ras signaling to changes in mRNA expression and growth. I have identified Myc is required but not sufficient for Ras-induced cell proliferation and growth through tRNA synthesis. Previously we have shown that TOR signaling regulates protein synthesis through RNA Pol III repressor, Maf1. I found that Maf1 RNAi increases tRNA synthesis in S2 cells. In addition, the decrease in tRNA synthesis induced by the MEK inhibitor is blocked in the presence of Maf1 RNAi suggesting Maf1 is downstream of Ras signaling pathway. My data point to control of tRNA synthesis possibly through Myc and/or Maf1 as a new mechanisms by which Ras signaling enhances protein synthesis to promote cell and tissue growth.

Citation Format: Shrivani Sriskanthadevan-Pirahas, Savraj S. Grewal. EGF/Ras/Erk signaling controls growth and proliferation through regulation of tRNA synthesis. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B13.
Abstract B22: Increased phosphorylation of eIF4E induces resistance to treatment with mTOR inhibitors together with AR antagonists in advanced prostate cancer
Authors: D'Abronzo Leandro S. , Crapuchettes Michael , Beggs Ryan , Vinall Ruth , Tepper Clifford , Siddiqui Salma , Mudryj Maria , Melgoza Frank , Durbin-Johnson Blythe , White Ralph deVere , Ghosh Paramita
Published: May 2017

The anti-androgen bicalutamide is widely used in the treatment of advanced prostate cancer (CaP) in many countries, but its effect on castration resistant CaP (CRPC) is limited. We previously showed that resistance to bicalutamide results from increased activation of the mechanistic target of rapamycin (mTOR); indicating a role for mTOR inhibitors in CaP treatment. Interestingly, a clinical trial testing combinations of the mTOR inhibitor RAD001 with bicalutamide were initially effective (PSA decline>50%) in 62.5% CRPC patients, but many initial responders later developed resistance. Here we investigate causes for their difference in response. Evaluation of various CRPC cell lines identified resistant vs sensitive in vitro models, and revealed that increased eIF4E phosphorylation at S209 is associated with resistance to the combination. To recognize potential causes of resistance, we demonstrated using a human tumor xenograft mouse model, that bicalutamide use is associated with an increase in eIF4E(S209) phosphorylation. Investigations revealed that AR suppressed eIF4E phosphorylation, while the use of anti-androgens relieved this suppression, thereby triggering its increase. Additional investigation on the consequences of increased eIF4E phosphorylation in human prostatectomy samples revealed that increased eIF4E phosphorylation strongly correlated with the cell proliferation marker Ki67, indicating a role for eIF4E in tumor growth. Inhibition of eIF4E phosphorylation by siRNA suppression or treatment with CGP57380 (an inhibitor of MAPK interacting serine-threonine kinases Mnk1/2, the eIF4E upstream kinase,) sensitized CRPC cells to RAD001+bicalutamide, while eIF4E overexpression induced resistance. Our results demonstrate that bicalutamide treatment induced an increase in eIF4E phosphorylation by inhibition of AR which otherwise suppressed this phosphorylation. Increased eIF4E phosphorylation then induced resistance to the combination of anti-androgens with mTOR inhibitors by increasing proliferation. These results also indicate that resistance to RAD001+bicalutamide can be prevented by the concurrent use of a Mnk1/2 inhibitor.

Citation Format: Leandro S. D'Abronzo, Michael Crapuchettes, Ryan Beggs, Ruth Vinall, Clifford Tepper, Salma Siddiqui, Maria Mudryj, Frank Melgoza, Blythe Durbin-Johnson, Ralph deVere White, Paramita Ghosh. Increased phosphorylation of eIF4E induces resistance to treatment with mTOR inhibitors together with AR antagonists in advanced prostate cancer. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B22.
Abstract B33: Translational control pathways form a molecular hub that regulates tamoxifen resistance in ER+ breast cancer
Authors: Geter Phillip A. , Schneider Robert J.
Published: May 2017

Currently, ER+ breast cancer is treated with adjuvant antiestrogen therapies (i.e. tamoxifen and raloxifene). Despite maintaining expression of the estrogen receptor, many women treated with adjuvant therapy develop resistance several years after curative care. In fact, resistance to tamoxifen therapy is responsible for a vast majority of deaths resulting from metastatic disease. Our lab and others have shown that upregulation of the abundance and/or activity of translation initiation factors eIF4E and eIF4G1 occurs widely in advanced breast cancer, selectively upregulating translation of certain mRNAs required for survival, proliferation, and metastasis. Therefore, we hypothesized that tamoxifen resistance in ER+ breast cancer involves selective mRNA translation mediated by hyperactivation of the mTORC1 translational control pathway via regulating the availability and activity of eIF4E. Tamoxifen resistant (R) and sensitive (S) ER+ cell lines have been developed by several labs by long-term cultivation in tamoxifen and are used in my work. We define here, using the aforementioned cell lines, a molecular hub consisting of the two translational control pathways, PI3K/Akt/mTOR and MAPK/ERK/MNK which converge on translation initiation factor 4E (eIF4E) increasing its availability and activity. We show that blocking eIF4E-mediated translation was able to resensitize drug resistant cells to tamoxifen; conversely, overexpression of eIF4E, without concurrent mTORC1 hyperactivity, was not sufficient to generate resistance. Furthermore, knockdown of two genes identified from our genome-wide translation state analysis, TEX14 and RUNX2, significantly impacted drug resistance and serve as a major regulators in disease progression. Our findings demonstrate that eIF4E is a key player regulating tamoxifen resistance in ER+ disease.

Citation Format: Phillip A. Geter, Robert J. Schneider. Translational control pathways form a molecular hub that regulates tamoxifen resistance in ER+ breast cancer. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B33.
Abstract B42: Combination of liquid chromatography-surface enhanced Raman spectroscopy and liquid chromatography-mass spectrometry to identify SUMOylated proteins due to nutrient restriction in colorectal cancer
Authors: Schroll Monica M. , Schultz Zachary D. , Hummon Amanda B.
Published: May 2017

Nutrient restriction, also known as caloric restriction, has been extensively examined for its positive impact on lifespan, immune system boost, and aging. Nutrient restriction, defined as providing essential nutrients but restricting total caloric intake, has shown to decrease disease rate in humans. In addition, nutrient restriction is implicated in decreasing cancer initiation and progression. We have previously established three dimensional cell culture models, known as spheroids, in the HCT 116 colorectal cancer cell line as a high throughput model for studying the proteomic changes associated with nutrient restriction. We found that SUMOylated proteins are up regulated in colorectal cancer 3D cell cultures when subjected to metabolic stress. The attachment of the SUMO protein leads to changes in subcellular location, DNA repair, transcriptional regulation, and mitosis. We will explore SUMOylated in response to nutrient restriction via a novel technique to detect biomolecules using LC-SERS. This method allows the can detection of chemical differences associated with biomolecule structure. We first will enhance this system to detect and quantify metabolites in a more complex matrix, such as a cell lysate. Once the methodology has been optimized we use LC-SERS to identify and quantitate SUMOylated proteins in response to NR. When compared to available MS methods to identified SUMOylated proteins, we hypothesize our novel LC-SERS methodology will be able to surpass the limitations found with MS methods. Nutrient restriction has overwhelming effects on cancer and this study will provides further evidence that SUMOlyation, in response to metabolic stress, has a role in cancer progression.

Citation Format: Monica M. Schroll, Zachary D. Schultz, Amanda B. Hummon. Combination of liquid chromatography-surface enhanced Raman spectroscopy and liquid chromatography-mass spectrometry to identify SUMOylated proteins due to nutrient restriction in colorectal cancer. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr B42.
Abstract IA02: Regulation of growth by the mTOR pathway
Authors: Sabatini David M.
Published: May 2017

mTOR is the target of the immunosuppressive and anti-cancer drug rapamycin and the central component of a nutrient- and hormone-sensitive signaling pathway that regulates cell growth and proliferation. We now appreciate that this pathway becomes deregulated in many human cancers and has key roles in the control of metabolism, cell and organ size, and aging. We have identified two distinct mTOR-containing proteins complexes, one of which regulates growth through S6K and another that regulates cell survival and metabolism through Akt. These complexes, called mTORC1 and mTORC2, define both rapamycin-sensitive and insensitive branches of the mTOR pathway. Over the last few years we have focused on how nutrients, particularly amino acids, regulate mTORC1. We have identified a complex signaling pathway that relays amino acid availability to mTORC1 through the heterodimeric Rag GTPases. We recently discovered several of the amino acid sensors for the pathway. I will discuss new results from our lab on the regulation and functions of mTORC1.

Citation Format: David M. Sabatini. Regulation of growth by the mTOR pathway. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr IA02.
Abstract IA04: Control of cell senescence by cancer-associated protein HuR and target noncoding RNAs
Authors: Abdelmohsen Kotb , Panda Amaresh C. , Grammatikakis Ioannis , Noh Ji Heon , Gorospe Myriam
Published: May 2017

Senescent cells accumulate in aging tissues, and their metabolic and gene expression profiles are linked to cancer and other age-associated pathologies. Our recent studies have focused on the cancer-associated RNA-binding protein HuR [1], a suppressor of senescence, and its interaction with different classes of noncoding RNAs—long noncoding RNAs (lncRNAs), microRNAs (miRNAs), and circular RNAs (circRNAs). I discuss the ribonucleoprotein (RNP) complexes that HuR forms with several noncoding RNAs that influence protein abundance and modulate the senescent phenotype. HuR association with lncRNAs such as LINCP21 suppresses the translation of select mRNAs [2], its interaction with lncRNA HOTAIR promotes the ubiquitin-mediated proteolysis of select proteins [3], and its association with RMRP enhances mitochondrial homeostasis [4], while its competition with 7SL modulates TP53 mRNA translation [5]. Likewise, HuR can bind microRNAs like let-7, which can function as tumor suppressors [6], modulating their availability to repress mRNAs bearing let-7 sites. Finally, our ongoing studies show that HuR can also bind circRNAs, an interaction that reduces the expression of select proliferative proteins and reduces cell division. In summary, HuR is well known for regulating target mRNAs encoding proteins that modulate cancer traits [1], but growing evidence indicates that HuR also regulates many target noncoding RNAs that govern protein expression patterns affecting growth arrest and cell senescence.

References:

[1] Abdelmohsen and Gorospe, WIRES RNA 2010

[2] Yoon et al., Mol Cell, 2012

[3] Yoon et al., Nat Commun, 2013

[4] Noh et al., Genes Dev, 2016

[5] Abdelmohsen et al., Nucleic Acids Res, 2014

[6] Yoon et al., Genes Dev 2015

Citation Format: Kotb Abdelmohsen, Amaresh C. Panda, Ioannis Grammatikakis, Ji Heon Noh, Myriam Gorospe. Control of cell senescence by cancer-associated protein HuR and target noncoding RNAs. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr IA04.
Abstract IA06: Oncogenic translation programs
Authors: Wendel Hans-Guido
Published: May 2017

New York, NY.

I will provide an overview of the lab's contribution to deciphering the role of aberrant mRNA translation in cancer. We initially reported that aberrant eIF4E expression can drive lymphomagenesis in vivo. Next, we noticed that eIF4E's oncogenic activity strictly required phosphorylation at S209 by MNK1/2 kinases. The latter is the basis of ongoing efforts to develop and test MNK kinase inhibitors for cancer applications. More recently, we dissected the molecular basis of the anti-cancer action of eIF4A inhibitors like silvestrol. Using the ribosome footprinting technology developed by the Weissman lab we noticed that eIF4A inhibition acutely and preferentially suppressed a select group of ~200 mRNAs. These are marked by repeated 5' UTR sequences that are predicted to fold into energetically favorable G-quadruplex structures. Notably, many of these eIF4A–dependent transcripts encode oncogenic transcription factors (e.g. MYC and MYB), a number of cell cycle regulators (e.g. CDK6, CCND3), and anti-apoptotic BCL2 family genes. These findings also begin to shed light on the overarching question of how aberrant translation may lead to cancer. We speculate that it is not simply a global increase in protein production but instead the activation of oncogenic translation programs. We will discuss these findings also in light of recent work proposing an additional mechanism of eIF4A action that emphasizes binding to ubiquitous RNA sequence elements over the enzymatic activity of eIF4A.

Citation Format: Hans-Guido Wendel. Oncogenic translation programs. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr IA06.
Abstract IA09: Translational control of the tumor microenvironment
Authors: Robichaud Nathaniel , Guo Qianyu , Rincon Sonia del , Miller Wilson H. , Siegel Peter , Hsu Brian , Sonenberg Nahum
Published: May 2017

Translational control has emerged as a critical determinant in tumorigenesis. The mRNA cap-binding protein eIF4E is an oncoprotein that plays an important role in cancer initiation and progression. We recently demonstrated that eIF4E phosphorylation on serine 209 by the Map Kinase Integrating Kinases (MNK1/2) promotes epithelial to mesenchymal transition, invasion and metastasis. We recently discovered a critical importance of eIF4E phosphorylation in the tumor microenvironment (TME) for the metastatic process. To investigate the role of eIF4E phosphorylation in the TME, we utilized a syngeneic model in which a murine mammary tumor cell line (66cl4) was orthotopically injected into mice bearing the non-phosphorylatable eIF4E ^S209A mutation and their WT counterparts. Tumor growth was monitored by caliper measurements, and tissues were collected for histological assessment and immunohistochemistry. The onset of tumor formation was significantly delayed in eIF4E ^S209A mice. However, established tumors showed no differences in growth, proliferation, apoptosis, vascularization or immune infiltration. Strikingly, eIF4E ^S209A mice were nearly completely resistant to the formation of lung metastases from primary mammary tumors. Metastatic potential in this model was correlated with neutrophil accumulation in the spleen, blood and lungs of WT mice, which was significantly reduced in eIF4E ^S209A mice. Furthermore, treatment of tumor-bearing WT mice with an inhibitor of MNK1/2 significantly reduced lung metastasis without affecting primary tumor growth. Considering that eIF4E phosphorylation in both the TME and cancer cells promotes metastasis, our findings support the development of MNK inhibitors for metastasis prevention.

Citation Format: Nathaniel Robichaud, Qianyu Guo, Sonia del Rincon, Wilson H. Miller, Peter Siegel, Brian Hsu, Nahum Sonenberg. Translational control of the tumor microenvironment. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr IA09.
Abstract IA12: Low rates of protein synthesis in hematopoietic stem cells are determined partly by relatively high levels of hypophosphorylated eIF4E-BP
Authors: Signer Robert A. J. , Qi Le , Morrison Sean J.
Published: May 2017

Hematopoietic stem cells (HSCs) synthesize less protein per hour, on average, than other hematopoietic progenitors. Limited protein synthesis appears to be a widely shared feature of adult stem cells. The low rate of protein synthesis is necessary for HSC maintenance as genetic changes that modestly increase or decrease protein synthesis each impair HSC function. However, the mechanisms that suppress protein synthesis in adult stem cells remain unexplored. We assessed a number of potential mechanisms and found that the reduced rate of protein synthesis in HSCs as compared to other hematopoietic progenitors is not explained by differences in proteasome activity, cell division rate, or mRNA content. However, adult bone marrow HSCs had increased amounts of hypophosphorylated eukaryotic initiation factor 4E binding protein1 (eIF4E-BP1) and eIF4E-BP2 as compared to other hematopoietic progenitors. Since unphosphorylated eIF4E-BP negatively regulates protein synthesis, this raised the possibility that eIF4E-BPs hypophosphorylation suppresses protein synthesis in HSCs. Consistent with this, genetic inactivation of eIF4E-BP1 and eIF4E-BP2 increased protein synthesis in HSCs and impaired their reconstituting activity. These findings provide insight into the mechanisms that promote adult tissue regenerative capacity by attenuating protein synthesis in stem cells.

Citation Format: Robert A. J. Signer, Le Qi, Sean J. Morrison. Low rates of protein synthesis in hematopoietic stem cells are determined partly by relatively high levels of hypophosphorylated eIF4E-BP. [abstract]. In: Proceedings of the AACR Special Conference on Translational Control of Cancer: A New Frontier in Cancer Biology and Therapy; 2016 Oct 27-30; San Francisco, CA. Philadelphia (PA): AACR; Cancer Res 2017;77(6 Suppl):Abstract nr IA12.