bluuebunny/crossref_metadata_2025 huggingface dataset:
Abstract A15: Epigenetic up-regulation of ribosome biogenesis and more aggressive phenotype triggered by the lack of the histone demethylase JHDM1B in mammary epithelial cells
Authors: Galbiati Alice , Penzo Marianna , Bacalini Maria Giulia , Onofrillo Carmine , Guerrieri Ania Naila , Garagnani Paolo , Franceschi Claudio , Treré Davide , Montanaro Lorenzo
Published: May 2017

Alterations of ribosome biogenesis and protein synthesis play a direct role in the development and the behavior of tumors. The accessibility and transcription of ribosomal genes are controlled at several levels, with their epigenetic regulation being one of the most important. Here we explored the JmjC domain-containing histone demethylase 1B (JHDM1B) function in the epigenetic control of rDNA transcription. Since JHDM1B is a negative regulator of gene transcription, we focused on the effects induced by its downregulation. We studied the consequences of inducible JHDM1B knock-down (KD) in cell lines derived from transformed (MDA-MB-231) and untransformed (MCF-10A) mammary epithelial cells. In these cellular models, sustained JHDM1B down-regulation triggered an increase in 45S pre-rRNA transcription and processing, associated with a re-modulation of the H3K36me2 levels at the rDNA loci. By means of the EpiTYPER assay, we observed that JHDM1B KD reproducibly induced quantitative changes in DNA methylation of specific CpG sites in rDNA genes. By polysomal profile analysis, we also found that JHDM1B KD induced an higher content of ribosomes in both the pre-polysomal and polysomal fractions indicating an increase in global protein synthesis. We then investigated in vitro and in vivo the behavior of cells after JHDM1B KD and the associated stimulation of ribosomes biogenesis. JHDM1B down-regulation conferred more aggressive features to the tested cellular models, which acquired a greater clonogenic and invasive potential in vitro. The study of tumors generated in nude Balb/c mice after xenografting MDA-MB-231 cells, indicated that JHDM1B KD triggered an incremental (although not statistically significant) trend in tumor growth. In addition, the selective nucleolar staining of sections from these tumors revealed a significant increase in the average nucleolar area after JHDM1B KD. Taken together, these data indicate that the reduction of JHDM1B leads to an increase in ribosome production and to a more aggressive cellular behavior in mammary gland cells.

Citation Format: Alice Galbiati, Marianna Penzo, Maria Giulia Bacalini, Carmine Onofrillo, Ania Naila Guerrieri, Paolo Garagnani, Claudio Franceschi, Davide Treré, Lorenzo Montanaro. Epigenetic up-regulation of ribosome biogenesis and more aggressive phenotype triggered by the lack of the histone demethylase JHDM1B in mammary epithelial 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 A15.
Abstract A17: Probing a translational switch involved in tumor angiogenesis
Authors: Ramachandran Maya , Mitra Somdeb , Gonzalez Ruben L.
Published: May 2017

As a tumor proliferates, it rapidly outgrows its blood supply, creating an oxygen-starved environment. Low oxygenation (hypoxia) suppresses the canonical biochemical pathway through which the translation of messenger RNAs (mRNAs) into proteins by the ribosome is typically initiated. Despite shutting down this general mechanism for initiating protein synthesis, the tumor can continue to initiate translation of a subset of mRNAs that are involved in angiogenesis and tumor survival. To explain this observation, it has been proposed that, in addition to the eukaryotic mRNA-specific 7-methyl guanosine cap at the 5' end, these pro-angiogenic mRNAs, of which Fibroblast Growth Factor-9 (FGF9) and Hypoxia Inducible Factor 1α (HIF1α) are prototypical members, contain highly stable structures in their 5' untranslated regions. These structures, also referred to as Cap Independent Translation Enhancers (CITEs), form part of a switch that activates a non-canonical pathway for initiating translation, presumably by binding directly to eukaryotic initiation factor 4G (eIF4G), thereby recruiting ribosomes in a manner distinct from the canonical 5' cap-dependent mechanism. To test this hypothesis, here we report the binding affinities of pro-angiogenic mRNAs, as well as control mRNAs lacking CITEs, to eIF4G as a measure of their ability to initiate translation in the hypoxic environment of a tumor. Understanding the dynamics of eIF4G-CITE interactions can inform the design and development of novel angiogenesis inhibitors that function by targeting these interactions.

Citation Format: Maya Ramachandran, Somdeb Mitra, Ruben L. Gonzalez, Jr. Probing a translational switch involved in tumor angiogenesis. [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 A17.
Abstract A20: Baseline IL-17 receptor signaling is essential for controlling aberrant JNK-dependent cellular proliferation via maintenance of endogenous level of ubiquitin-editing enzyme A20
Authors: Yan Chi , Lei Yang , Greenshields Anna L. , Hoskin David W. , Lin Tong-Jun , Wang Jun
Published: May 2017

The molecular mechanisms underlying aberrant activation of NF-κB and JNK in cancer remain incompletely understood. Here, we demonstrate that baseline IL-17 receptor (IL-17R) signaling is essential for controlling aberrant NF-κB and JNK activation, and restraining JNK-dependent homeostatic cellular proliferation. Using a shRNA knockdown approach, we demonstrated in two murine tumor cell lines that IL-17RA silencing markedly enhanced tumor cell growth in vitro and in vivo. Through mapping IL-17R signaling pathways, we further demonstrated that baseline IL-17A/IL-17R signaling actively restrained JNK phosphorylation in vitro and in vivo via maintenance of basal expression of the ubiquitin-editing enzyme A20, a negative regulator of NF-κB and JNK. Remarkably, IL-17RA reconstitution evidently restored the A20 level, and suppressed cell proliferation and JNK activity in tumor cells. The reconstitution of A20 in IL-17RA knockdown subclones is able to restore the normal rate of cellular proliferation and associated JNK/c-Jun activity. Finally, meta-analysis of human cancer microarray and RNA sequencing datasets confirmed close co-expression of IL-17RA and A20. Furthermore, alterations (mutation, upregulation or downregulation) of IL-17RA level in melanoma and ER+ breast cancer patients showed poor survival rate compared to the respective patients with normal baseline IL-17RA expression. Together, our data demonstrates a previously unrecognized molecular mechanism underlying aberrant activation of NF-κB and JNK in cancer cells. This work has significantly advanced our understanding of the biological role of the proinflammatory IL-17R signaling and highlights its unique role in the maintenance of A20 to regulate the pathogenesis of human cancer at translational level.

Citation Format: Chi Yan, Yang Lei, Anna L. Greenshields, David W. Hoskin, Tong-Jun Lin, Jun Wang. Baseline IL-17 receptor signaling is essential for controlling aberrant JNK-dependent cellular proliferation via maintenance of endogenous level of ubiquitin-editing enzyme A20. [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 A20.
Abstract A22: Hypoxia-mediated translational control of hypoxia inducible factor 1 alpha through aldolase A feedback regulation in lung carcinogenesis
Authors: Chang Yu-Chan , Hsiao Michael
Published: May 2017

Lung cancer cells grow in-situ during low-oxygen situation and usually results in invasion and is frequently recurrent after therapy. However, the oxygen-mediated translation control of the metabolic events in lung cancer remains largely unknown. By using the integrated transcriptomics data and the shRNA library against glycolytic enzymes, here we identified that Aldolase A (ALDOA) up-regulation is highly correlated with migratory/invasive activity of lung cancer cells and poorer clinical outcomes. Significantly, knockdown of Aldolase A inhibited in vitro and in vivo migratory/invasive activity of lung cancer cell line with high ALDOA expression. Complementary, enforced overexpression of exogenous ALDOA promoted migration/invasion. Furthermore, microarray and Ingenuity pathway analyses reveal that ALDOA-driven lung cancer metastasis likely recruits Hypoxia-inducible factor 1 alpha (HIF1α)-associated signaling pathway. There were no significance changes at the mRNA level of HIF1α in ALDOA two-way models. However, HIF1α protein was found stabilized in hypoxic or normoxic condition through ALDOA overexpression to decrease prolyl hydroxylase (PHD) activity for hydroxylation-form of HIF1α to activate downstream genes including CXCR4, MMP9 in lung carcinogenesis. Interesting, HIF1α also was found to bind hypoxia-response element (HRE) domain of ALDOA to activate its transcription and form a positive feedback loop. IHC staining results further demonstrate that Aldolase A and HIF1α expression is positively correlated in clinical lung cancer tissues and the signature of high-level Aldolase A and HIF1α; expression strongly associates with worst survival probability in lung cancer patients. Our results not only unveil molecular mechanism by which Aldolase A promotes lung cancer metastasis via inducing the HIF1α activity but also provide a novel therapeutic strategy to combat malignant lung cancer via targeting ALDOA.

Citation Format: Yu-Chan Chang, Michael Hsiao. Hypoxia-mediated translational control of hypoxia inducible factor 1 alpha through aldolase A feedback regulation in lung carcinogenesis. [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 A22.
Abstract A29: Targeting adenylate kinase-4 modulation of HIF-1α: Stability identifies Withaferin-A suppresses lung cancer metastasis
Authors: Hsiao Michael
Published: May 2017

Aberrant activation of hypoxia inducible factor (HIF-1α) often plays a crucial role in promoting metabolic reprogramming and metastatic dissemination. Here we report functional evidences of adenylate kinase 4 (AK4), one of the hypoxia-responsive genes, in enhancing HIF-1α; transcriptional activity to drive epithelial-to-mesenchymal transition (EMT). By analyzing lung adenocarcinoma microarray datasets, we identified AK4-associated metabolic gene signature and revealed HIF-1α; was transcriptionally activated and associated with poor prognosis. Immunohistochemistry analysis confirms the positive correlation between AK4 and HIF-1α; in non-small cell lung (NSCLC) cancer patients. Overexpression of AK4 induces metabolic shift towards aerobic glycolysis and increases intracellular reactive oxygen species (ROS), which exaggerates HIF-1a; protein expression under hypoxia and concurrently induces EMT in a HIF-1α-dependent manner. Furthermore, overexpression of AK4 reduces hypoxic necrosis in tumors and promotes liver metastasis in vivo. Connectivity map analysis of AK4 gene signature identifies Withaferin-A as a potential inhibitor to inverse AK4 signature and proven to be a potent anti-metastatic agent in orthotopic xenograft model of lung cancer. Our findings offer an alternative strategy to treat metastatic lung cancer via targeting AK4-HIF-1α axis.α

Citation Format: Michael Hsiao. Targeting adenylate kinase-4 modulation of HIF-1α: Stability identifies Withaferin-A suppresses lung cancer metastasis. [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 A29.
Abstract A30: Oncogenic MCT-1 activation deregulates oxidative metabolism and promotes lung tumor progression and metastasis
Authors: Tseng Hong-Yu , Chen Yen-An , Jen Jayu , Wang Yi-Ching , Hsu Hsin-Ling
Published: May 2017

Multiple copies in T-cell malignancy 1 (MCT-1) is involved in transcription regulation and translation initiation. We have identified that MCT-1 plays important roles in cell transformation and survival, catastrophic mitosis and genomic instability. Enhanced MCT-1 activity decreases p53 promoter function, protein stability and activity, thereby overexpressing MCT-1 further promotes tumorigenicity in a p53-null background. Enhanced MCT-1 activation induces SHCs (Src homology 2 domain containing transforming proteins) that transmit EGFR signaling to extracellular-regulated kinase (ERK) and AKT pathway. Here, we identify a novel carcinoma metabolism pathway involving MCT-1-YY1-EGFR-MnSOD axis which confers oxidative resistance, changes tumor microenvironments and promotes tumor development. Inhibiting this oncogenic pathway may be a novel clinical intervention approach to prevent tumor progression and metastasis.

Aims: Reactive oxygen species (ROS) promote tumor progression and metastasis, but the underlying mechanism remains unclear. We aim to investigate whether the oncogenic pathway enhances the generation of ROS, alters tumor microenvironment and potentiates metastasis. Results: We found that oncogene MCT-1 (multiple copies in T-cell malignancy 1) stimulated intracellular ROS formation and mitochondrial superoxide production in relationship with the deregulation of antioxidants and redox signaling. Enhanced MCT-1 activation induced the YY1-EGFR-MnSOD signaling cascade which prevented cells against oxidative damage and promoted tumor development. Importantly, MCT-1 overexpressing in lung cancer cells promoted tumor angiogenesis and necrosis along with increase of tumor-promoted M2 macrophages and cancer-associated myofibroblasts in stroma, which potentially provided a malignant microenvironment for tumor progression and metastasis. Conversely, restricting ROS generation and targeting YY1 suppressed the MCT-1-EGFR-MnSOD pathway and invasion ability in lung cancer cells. Clinical results confirm that MCT-1 overexpression is link to poor clinical outcomes and associates with hyper-activation of YY1, EGFR and MnSOD in patients with lung cancer. Importantly, MCT-1 protein enrichment is often identified in late stage and lymph node metastasis of lung cancer. Innovation and Conclusion: Our data reveal a previously unrecognized mechanism of the oxidative metabolism involving MCT-1-YY1-EGFR-MnSOD network which alters tumor microenvironments and promotes tumor progression and metastasis.

Citation Format: Hong-Yu Tseng, Yen-An Chen, Jayu Jen, Yi-Ching Wang, Hsin-Ling Hsu. Oncogenic MCT-1 activation deregulates oxidative metabolism and promotes lung tumor progression and metastasis. [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 A30.
Abstract A31: eIF4F links translation to energy stress response in cancer
Authors: Hulea Laura , Cargnello Marie , Gravel Simon-Pierre , Im Young , McLaughlan Shannon , Zhao Yunhua , Ching Jenna , Cai Yutian , Larsson Ola , Ohh Michael , Ursini-Siegel Josie , St-Pierre Julie , Pollak Michael , Topisirovic Ivan
Published: May 2017

Protein synthesis is one of the most energy consuming process in the cell. Oncogenic kinases (e.g. EGFR/HER2, BCR/ABL and BRAF) play a central role in reprogramming translation and energy metabolism in neoplasia, whereby cancer cells must provide sufficient ATP to support increased levels of protein synthesis required for neoplastic growth. The downstream mechanisms that link translational machinery and energy homeostasis in cancer, however, remain largely unknown.

We found that widely used anti-diabetics (biguanides) abrogate adaptations to EGFR/HER2 inhibitor-induced energetic stress, which results in synergistic anti-neoplastic effects both in vitro and in vivo. In turn, breast cancer cells in which 4E-BP1/2 expression was abrogated by CRISPR were partially resistant to the combination of EGFR/HER2 inhibitors and biguanides. This was paralleled by the inability of the drugs to inhibit the eIF4F complex assembly and translation of mRNAs encoding important metabolic regulators including those involved in serine biogenesis (PHGDH, PSAT1) and one carbon metabolism (MTHFD1L).

Comparable results were observed when BRAF and BCR/ABL inhibitors were combined with biguanides, which suggests that translational regulation of metabolic genes via the mTORC1/4E-BE/eIF4E pathway plays a major role in energy stress response in cancer.

Together our findings demonstrate that the eIF4F complex is an important mediator of metabolic adaptation in response to the combination of biguanides and clinically-used kinase inhibitors and suggest that the efficiency of such anti-cancer strategies are dependent on the integrity of the translation initiation machinery.

Citation Format: Laura Hulea, Marie Cargnello, Simon-Pierre Gravel, Young Im, Shannon McLaughlan, Yunhua Zhao, Jenna Ching, Yutian Cai, Ola Larsson, Michael Ohh, Josie Ursini-Siegel, Julie St-Pierre, Michael Pollak, Ivan Topisirovic. eIF4F links translation to energy stress response in 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 A31.
Abstract A41: Crosstalk between adipocytes and breast cancer promotes epithelial-mesenchymal transition
Authors: Eun-Sol Kim , Seung Koo Ja
Published: May 2017

Introduction: Adipocytes are known to be involved in epithelial-mesenchymal transition (EMT) associated with tumor cell invasion and metastasis in several cancers. However, the role of adipocytes in the EMT of breast cancer cells is poorly understood. The purpose of this study was to investigate the involvement of adipocytes in the EMT in breast cancer.

Methods: We investigated that co-culture with adipocytes induces morphological changes, proliferation activity, EMT markers expression, status of migration and invasion in MCF-7, MDA-MB-453, MDA-MB-435S, MDA-MB-231, and MDA-MB-468 cell lines. By tissue microarray (TMA) of 296 cases of human breast cancer, immunochemical staining for estrogen receptor (ER), progesterone (PR), HER2, Ki-67, N-cadherin, Twist1, HMGA2, TGFb, and S100A4 was conducted. We classified into fibrous stroma and adipose stroma (when adipose tissue is at least 50% of the entire tumor stroma) based on standard histological classification.

Results: After co-culture with adipocytes, MCF-7, MDA-MB-435S, and MDA-MB-231 cells exhibited elongated spindle-like morphology and increased proliferation; MDA-MB-435S and MDA-MB-231 cells also showed increased dispersion. In all tested breast cancer cells, adipocytes induced migration and invasion. The EMT-like phenotypic changes and increased cell migration and invasion were accompanied by the upregulation of matrix metallopeptidase 9 and TWIST1. Consistently, breast cancer tumors with the adipose stroma showed higher TWIST1 expression than those with the adipose stroma; however, no difference was observed in the levels of other EMT-related proteins.

Conclusion: Adipocytes enable breast cancer cells to acquire aggressive tumor biology by inducing EMT features, and breast cancer with adipose stroma expresses EMT markers as breast cancer with fibrous stroma.

Citation Format: Lee YuKyung, Kim Eun-Sol, Koo Ja Seung. Crosstalk between adipocytes and breast cancer promotes epithelial-mesenchymal transition. [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 A41.
Abstract A46: Wnt5a signals through DVL1 to repress ribosomal DNA transcription by RNA polymerase I
Authors: Dass Randall , Sarshad Aishe , Carson Brittany , Feenstra Jennifer , Kaur Amanpreet , Obrdlik Ales , Parks Matthew , Prakash Varsha , Love Damon , Pietras Kristian , Serra Rosa , Blanchard Scott , Percipalle Piergiorgio , Brown Anthony , Vincent Clara Theresa
Published: May 2017

Ribosome biogenesis is essential for cell growth and proliferation and is commonly elevated in cancer. Accordingly, numerous oncogene and tumor suppressor signaling pathways target rRNA synthesis. In breast cancer, non-canonical Wnt signaling by Wnt5a has been reported to antagonize tumor growth. Here, we show that Wnt5a rapidly represses rDNA gene transcription in breast cancer cells and generates a chromatin state with reduced transcription of rDNA by RNA polymerase I (Pol I). These effects were specifically dependent on Dishevelled1 (DVL1), which accumulates in nucleolar organizer regions (NORs) and binds to rDNA regions of the chromosome. Upon DVL1 binding, the Pol I transcription activator and deacetylase Sirtuin 7 (SIRT7) releases from rDNA loci, concomitant with disassembly of Pol I transcription machinery at the rDNA promoter. These findings reveal that Wnt5a signals through DVL1 to suppress rRNA transcription. This provides a novel mechanism for how Wnt5a exerts tumor suppressive effects and why disruption of Wnt5a signaling enhances mammary tumor growth in vivo.

Note: This abstract was not presented at the conference.

Citation Format: Randall Dass, Aishe Sarshad, Brittany Carson, Jennifer Feenstra, Amanpreet Kaur, Ales Obrdlik, Matthew Parks, Varsha Prakash, Damon Love, Kristian Pietras, Rosa Serra, Scott Blanchard, Piergiorgio Percipalle, Anthony Brown, Clara Theresa Vincent. Wnt5a signals through DVL1 to repress ribosomal DNA transcription by RNA polymerase I. [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 A46.
Abstract B02: A regulatory role for codon bias in KRAS-driven tumor progression and therapeutic resistance
Authors: Kaltenbrun Erin , Ali Moiez , Stephens Sarah Jo , Counter Christopher , Wood Kris
Published: May 2017

The RAS genes HRAS, NRAS, and KRAS are mutated in a quarter of all human cancers to drive the initiation and maintenance of cancer. While all three genes encode nearly identical proteins, KRAS is highly enriched, compared to the other isoforms, in rare codons. These rare codons impede translation and subsequent protein expression. Despite this, increased KRAS expression and signaling is associated with malignancy and cancer progression, and KRAS mutations have been implicated as drivers of resistance to diverse targeted therapies. Using a pathway-activating genetic screen in a panel of human cancer cell lines, we find that mutant HRAS actually has greater resistance conferring potential than mutant KRAS. This differential resistance is governed by codon bias, suggesting that KRAS-driven resistance is limited by inefficient protein expression. We hypothesized that KRAS-driven cancer progression and primary resistance to a targeted therapeutic, such as an EGFR inhibitor, is dependent upon both the presence of a KRAS mutation as well as the ability of cancer cells to overcome this translational barrier. Indeed, we find that KRAS-mutant cancer cells globally upregulate translation, which results in enhanced expression of mutant KRAS and the formation of a translationally primed state that can be therapeutically exploited using inhibitors of protein translation. Collectively, these findings reveal a critical regulatory role for codon bias in mediating KRAS-driven therapeutic resistance and cancer progression. Ongoing work seeks to more precisely define the mechanisms governing KRAS translation in the setting of cancer and therapeutic resistance to obtain more specific approaches to target these tumors.

Citation Format: Erin Kaltenbrun, Moiez Ali, Sarah Jo Stephens, Christopher Counter, Kris Wood. A regulatory role for codon bias in KRAS-driven tumor progression and therapeutic resistance. [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 B02.
Abstract B07: Loss of APC induces a dependence on elevated eIF2B5 function in colorectal cancer
Authors: Peter Stefanie , Uthe Friedrich-Wilhelm , Eilers Martin , Germer Christoph-Thomas , Wiegering Armin
Published: May 2017

Colorectal cancer (CRC) is the most common gastrointestinal malignancy and one of the leading causes of cancer death worldwide. Truncating mutations of the tumor suppressor APC that lead to deregulated WNT signaling are driver mutations in CRC. APC and its downstream effector, β-catenin, are regarded as non-druggable, prompting the search for novel interactions essential for survival of cells that have lost APC function. Here, we have restored doxycycline-inducible expression of full-length APC (APC wt) in SW480 cells, which carry truncated APC (APC mut). To identify genes that are essential for viability of APC mut cells, we conducted an shRNA screen targeting 5,000 genes with 25,000 shRNAs. The best scoring differential hits were multiple shRNAs that target the translation initiation factor eIF2B5, a subunit of the guanidine exchange factor (GEF) for eIF2. Validation experiments demonstrate a strong synthetic lethal effect of eIF2B5 knockdown with APC truncation in SW480 cells that can be rescued by APC induction. There is a clear survival window, which we can visualize using several shRNA sequences with different knockdown efficiencies.

We confirm previous observations that loss of APC function results in an increase of global protein synthesis. Loss of APC also strongly induces expression of eIF2B5 and other subunits of eIF2B. Knockdown of eIF2B5 reduces overall protein translation. Although eIF2 function and overall ribosomal assembly are compromised upon depletion of eIF2B5, MYC protein levels are strongly upregulated, arguing that MYC can be translated in an eIF2-independent manner. Apoptosis upon eIF2B5 knockdown strictly depends on MYC upregulation. APC mut cells also display higher basal levels of the unfolded protein response (UPR) markers CHOP and ATF4, which are both further enhanced by eIF2B5 depletion. The UPR branch reflected by CHOP induction may contribute to cell death in our system.

In conclusion, our data demonstrate a dual regulatory mechanism in which loss of APC induces expression of both MYC and eIF2B5. Full eIF2 activity is required to restrict the pro-apoptotic activity of MYC in APC mut cells. Thus, interfering with eIF2B5 function as GEF or GDF may be a promising treatment strategy for cells with truncated APC.

Citation Format: Stefanie Peter, Friedrich-Wilhelm Uthe, Martin Eilers, Christoph-Thomas Germer, Armin Wiegering. Loss of APC induces a dependence on elevated eIF2B5 function 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 B07.
Abstract B14: Evidence that Tma20 and Tma22 do not promote translation re-initiation in yeast
Authors: Torrance Victoria , Lydall David
Published: May 2017

Translation Machinery Association 20 (Tma20) and Tma22 are two conserved proteins which form a complex involved in translation initiation. The human homolog of TMA20 is an oncogene, originally identified in a T-cell lymphoma and has been shown to induce cell proliferation. Tma20 and Tma22 homologs in Drosophila have been shown to promote translation of mRNAs which contain uORFs by promoting translation re-initiation. uORFs serve as major regulators of gene expression, repressing translation. In yeast Tma20 and Tma22 have recently been shown to have a role in telomere biology by decreasing fitness of cells with uncapped telomeres. To understand how Tma20 and Tma22 affect growth of cells with uncapped telomeres we have investigated translation re-initiation in yeast using new luciferase reporter constructs. Using transcript leader sequences from 22 genes we showed that, as expected, the majority of uORFs repressed expression but found no evidence to suggest that Tma20 or Tma22 promote translation re-initiation in 21 of these genes. However our data suggests that Tma20 and Tma22 inhibit translation re-initiation of the remaining gene, BRE4. Our data suggests that the function of Tma20 and Tma22 is not conserved from Drosophila to yeast. Our finding that Tma20 and Tma22 inhibit translation re-initiation on BRE4 is in agreement with studies in mammalian cells which have shown that Tma20 and Tma22 promote the dissociation of 40S ribosomal subunit from mRNA following translation termination. Our data suggests that perhaps the human homologs of Tma20 and Tma22 may not promote translation re-initiation as has previously been assumed.

Citation Format: Victoria Torrance, David Lydall. Evidence that Tma20 and Tma22 do not promote translation re-initiation in yeast. [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 B14.
Abstract B25: Discovery of molecular probes inhibiting La:RNA interactions in cancer cells
Authors: Sommer Gunhild , Fedarovich Alena , Kota Venkatesh , Peterson Yuri K. , Heise Tilman
Published: May 2017

The RNA-binding protein La is overexpressed in a number of tumor tissues and is proposed to support tumorigenesis via binding to mRNAs encoding tumor-promoting and anti-apoptotic factors to facilitate their translation. Our data suggest that those mRNAs might need La to be translated mainly in a cap-independent mechanism in cancer cells. Hence, small molecules able to block the binding of La to specific RNAs could represent a novel therapeutic strategy for cancer treatment.

In an attempt toward this approach we developed a high-throughput fluorescence polarization assay to screen small compound libraries for molecules inhibiting the binding of La to an RNA element derived from cyclin D1 mRNA. Herein we describe a robust fluorescence polarization assay and the validation of primary hits by electrophoretic mobility shift assays. Using isothermal titration calorimetry we show that a compound binds to La and molecular modeling suggests an interaction between the compound and the RNA recognition motif of La.

We have shown recently that La protects cells against cisplatin treatment by stimulating the protein synthesis of the anti-apoptotic factor Bcl2. Here we show by RNA immunoprecipitation experiments that one small compound specifically impairs the association of La with Bcl2 mRNA, reduces Bcl2 protein expression and sensitizes cells for cisplatin-induced cell death.

Taken together, herein we report the development of a high-throughput fluorescence polarization assay to identify small compounds able to impair the binding of cancer-associated La to RNAs encoding tumor-promoting and anti-apoptotic factors in vitro and cancer cells.

Citation Format: Gunhild Sommer, Alena Fedarovich, Venkatesh Kota, Yuri K. Peterson, Tilman Heise. Discovery of molecular probes inhibiting La:RNA interactions in cancer 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 B25.
Abstract B27: Morphological changes, cadherin switching, and growth suppression in pancreatic cancer by GALNT6 knockdown
Authors: Tarhan Yunus Emre , Taigo Kato , Jang Miran , Nakamura Yusuke , Park Jae-Hyun
Published: May 2017

Pancreatic Cancer has one of the lowest rates of survival among other cancers. Although molecular targeted therapy has been widely applied for many types of cancer, no effective treatment has been developed for the patients of pancreatic cancer. We previously suggested that GALNT6 (polypeptide N-acetylgalactosaminyltransferase 6) is a promising molecular target in breast cancer by O-type glycosylation of Mucin1. Interestingly, GALNT6 is also up-regulated in pancreatic cancer where Mucin proteins are intensively O-glycosylated, indicating a critical role of GALNT6 in pancreatic cancer. In this study we found that knockdown of GALNT6 using siRNAs decreased Muc4 protein as well as transcription level in pancreatic cancer cells. The knockdown of GALNT6 also decreased HER2 and ERK, interacting proteins of Mucin 4, accompanied by drastic reduction of pancreatic cancer cell viability. Further analysis revealed that knockdown of GALNT6 led to cell morphologic changes like the mesenchymal to epithelial transition, which was in concordant with the cadherin switching mechanism—increase of E-cadherin meanwhile decrease of P-cadherin level. Taking into considerations of important roles of Mucin 4 in growth, invasion and resistance to gemcitabine, our findings imply that targeting GALNT6 is a very promising therapeutic strategy for the treatment of pancreatic cancer patients who still have very limited treatment modalities

Citation Format: Yunus Emre Tarhan, Kato Taigo, Miran Jang, Yusuke Nakamura, Jae-Hyun Park. Morphological changes, cadherin switching, and growth suppression in pancreatic cancer by GALNT6 knockdown. [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 B27.
Abstract B30: The RNA-binding protein LARP1 is a cancer therapeutic target
Authors: Ghazaly Essam A. , Quesne John Le , Jiang Dahai , Mangala Selanere L. , Chettle James , Rodriguez-Aguayo Cristian , Lopez-Berestein Gabriel , Gnanaranjan Chathunissa , Mura Manuela , Stavraka Chara , Sood Anil K. , Blagden Sarah P.
Published: May 2017

Ovarian cancer is the most lethal of gynecological cancers killing 60% of women diagnosed with the disease within 5 years. The major contributor to this high mortality is the emergence of chemotherapy resistance; the tumor is initially sensitive to chemotherapy (especially cisplatin, the mainstay of treatment) but recurs with increasingly resistant disease. Effective methods of overcoming treatment resistance are a major unmet medical need and would prolong survival and improve quality of life for women with this disease. We have shown previously that the RNA binding protein La-related protein 1 (LARP1) binds and post-transcriptionally regulates the stability of mRNAs encoding cell survival and stress response proteins including mTOR, BCL2 and BIK. In ovarian cancer tissue, elevated levels of LARP1 protein correlate with adverse survival outcome and chemotherapy resistance. In vivo inhibition of LARP1 using therapeutic RNA interference (packaged in DOPC nanoliposomes) restores cisplatin sensitivity in resistant ovarian cancer xenograft models. In concurrent studies, using a novel ultra-high performance liquid chromatography tandem mass spectrometry method, we have quantified LARP1 in the circulation of ovarian cancer patients and found that high levels correspond with poor prognosis. Circulating LARP1 has prognostic significance and may act as a companion biomarker to a LARP1 inhibitor. We conclude that LARP1, through its regulation of multiple mRNAs within critical pathophysiological pathways, is an important cancer therapeutic target and that RNA-based drugs designed to target LARP1 restore chemotherapy sensitivity in xenograft models.

Citation Format: Essam A. Ghazaly, John Le Quesne, Dahai Jiang, Selanere L. Mangala, James Chettle, Cristian Rodriguez-Aguayo, Gabriel Lopez-Berestein, Chathunissa Gnanaranjan, Manuela Mura, Chara Stavraka, Anil K. Sood, Sarah P. Blagden. The RNA-binding protein LARP1 is a cancer therapeutic target. [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 B30.
Abstract B34: Inhibitor of DNA binding (Id) regulates glioma infiltration on myelin tracts by suppressing Nogo receptor 1
Authors: Hong JunHee , Oh Young Taek , Kim Tae Hoon , Park Jong Bae
Published: May 2017

Myelin-associated infiltration is mostly attributed to clinical failure of glioma. Identifying molecular mechanisms and identity of infiltrating cells are major concern in glioma research. Here, we show that stem cell properties of glioma contribute to myelin-associated infiltration by the down-regulation of NgR1, a receptor for myelin-associated inhibitors (MAIs). Inhibitors of DNA binding (Id) proteins, regulators of early neural development, are responsible for down-regulation of NgR1. During differentiation and dedifferentiation of glioma stem cells (GSCs) Id/NgR1 regulation was reversible, and correlated to the infiltrative capacity of GSCs. Remarkably, NgR1 overexpression in mouse xenograft blocks infiltration of GSCs on myelin and significantly increased survival. NgR1 and Id1/4 levels are inversely correlated and low expression of NgR1 portends poor prognosis in glioma patients. Our findings clarify that functional significance of NgR1 regulation and provide first molecular evidence for myelin-associated infiltration. Our work suggests Id-NgR1 axis as a novel prognostic marker and proposes this axis as a potential targets for future therapeutic intervention for the myelin-associated glioma infiltration.

Citation Format: JunHee Hong, Young Taek Oh, Tae Hoon Kim, Jong Bae Park. Inhibitor of DNA binding (Id) regulates glioma infiltration on myelin tracts by suppressing Nogo receptor 1. [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 B34.
Abstract B46: Activation of TWIST1 by COL11A1 decreases cell sensitivity to paclitaxel by modulating NFκB -mediated Iκκβ expression
Authors: Wu Yi-Hui , Chou Cheng-Yang
Published: May 2017

Background: We have shown that collagen type XI alpha 1 (COL11A1) promotes ovarian tumorigenesis via upregulating the Transforming growth factor beta 1 (TGF-β)/ Matrix metalloproteinases 3 (MMP3) axis and upregulated COL11A1 expression enhanced metastatic potential to the lungs. COL11A1 expression is also associated with chemoresistance to cisplatin and paclitaxel in ovarian cancer cells. In this study, we verified how COL11A1 to regulate twist-related protein 1 (TWIST1) in ovarian cancer cells.

Methods: ES2 and TOV-21G cells transfected with a small interference RNA of COL11A1 (shCOL11A1) and OVCAR3 and OVCAR4 cells transfected with a COL11A1 expression plasmid. Site-directed mutagenesis assay, luciferase assay, chromatin immunoprecipitation assay, immunofluorescence assay, anchorage-independent soft-agar assay, invasion assay and xenograft animal study were performed in this study. COL11A1 and TWIST1 mRNA expression levels of 104 ovarian tumors were determined by real-time RT-PCR.

Results: We found that the level of COL11A1 expression in a panel of ovarian cancer cells was positively correlated with the expressions of TWIST1 and Iκκβ. Mechanistic studies indicated that a decrease in TWIST1 caused by COL11A1-suppressed Iκκβ transcription was achieved by derepression of binding of Sp1 to the Iκκβ promoter. COL11A1-mediated nuclear factor-kappaB (NF-κB) activation, via the activation of Iκκβ transcription, promoted anchorage-independent soft-agar growth, invasion and xenograft tumor formation, which was associated with epithelial-to-mesenchymal transition. In addition, TWIST1 messenger RNA level was positively associated with COL11A1 messenger RNA expression level in ovarian tumors.

Conclusions: COL11A1 activates NF-κB signaling by increasing Iκκβ transcription, which results in progression of ovarian cancer and poorer patient outcomes. We suggest that Iκκβ may potentially be targeted in patients with COL11A1-positive tumors.

Citation Format: Yi-Hui Wu, Cheng-Yang Chou. Activation of TWIST1 by COL11A1 decreases cell sensitivity to paclitaxel by modulating NFκB -mediated Iκκβ expression. [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 B46.
Abstract IA03: mTORC1/S6K1: Regulation of RNA biogenesis, protein synthesis, and cell metabolism
Authors: Blenis John , Lee Gina , Dempsey Jamie , England Christina
Published: May 2017

The mTOR Complex 1 (mTORC1) signaling pathway has evolved to sense and respond to cellular energy status, nutrient availability and surrounding oxygen concentrations. In addition, mTORC1 signaling can be further activated by mitogen- and hormone-stimulated kinases including Akt, ERK and RSK, and suppressed by mTORC1 and its effector S6K1, via a variety of negative feedback loops. This incredible integration of extracellular and intracellular cues translates into carefully regulated outputs that control cell growth, motility and survival. A major mechanism through which mTOR regulates downstream processes is via the regulation of gene expression, mRNA processing, protein synthesis and protein degradation. In an mTOR phosphoproteomic screen, we and others identified SR Protein Kinase 2 (SRPK2) as a potential downstream effector of mTORC1. I will discuss a novel mechanism by which SRPK2 is regulated and contributes to mTORC1-dependent regulation of lipid metabolism via the regulation of mRNA processing.

Citation Format: John Blenis, Gina Lee, Jamie Dempsey, Christina England. mTORC1/S6K1: Regulation of RNA biogenesis, protein synthesis, and cell metabolism. [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 IA03.
Abstract IA08: Role of the RNA binding protein UNR/CSDE1 in cancer progression
Authors: Gebauer Fatima
Published: May 2017

RNA binding proteins (RBPs) are gaining great attention in cancer research for their potential to regulate essentially every hallmark of tumor development. Yet, the molecular mechanisms that underlie these capacities are unclear, particularly in aggressive cancers such as melanoma, where RBPs remain largely uncharacterized. Here we show that the conserved RBP UNR/CSDE1 is over-expressed in melanoma tumors and promotes invasion and metastasis. iCLIP-Seq, RNA-Seq and ribosome profiling combined with in silico studies unveiled sets of pro-metastatic factors coordinately regulated by UNR as part of RNA regulons. In addition to RNA steady state levels, UNR was found to control many of its targets at the level of translation elongation/ termination. Our results identify UNR as an oncogenic modulator of melanoma progression, unravel the underlying molecular mechanisms, and identify potential targets for this therapeutically challenging malignancy.

Citation Format: Fatima Gebauer. Role of the RNA binding protein UNR/CSDE1 in cancer progression. [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 IA08.
Abstract IA13: Ribosome stalling and disease
Authors: Ackerman Susan L.
Published: May 2017

La Jolla, CA.

Protein synthesis is vital for cell function and disturbances in translation are associated with cancer, neurological disorders and other diseases. Although regulation of translation is thought to largely occur at initiation, elongation, the reiterative addition of amino acids by the ribosome, is emerging as a translational phase that is also highly regulated. Transfer RNAs, the adaptor molecules essential for elongation are encoded by several hundreds of nuclear genes in higher eukaryotes suggesting great functional redundancy. Our work has defined epistatic interactions between mutations in a mammalian tRNA gene and a novel ribosome rescue factor, defining the importance of individual tRNA genes in translation and the pathologies that can arise from disruptions in this process.

Citation Format: Susan L. Ackerman. Ribosome stalling and disease. [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 IA13.
Abstract IA20: Monitoring translation in space and time with ribosome profiling
Authors: Weissman Jonathan
Published: May 2017

The ability to sequence genomes has far outstripped approaches for deciphering the information they encode. We have developed a suite of techniques based on ribosome profiling (deep sequencing of ribosome protected fragments) that dramatically expand our ability to follow translation in vivo. I will present recent applications of our ribosome profiling approach including the following: (1) Development of ribosome profiling protocols for a wide variety of eukaryotic and prokaryotic organisms. (2) Uses of ribosome profiling to globally monitor when chaperones, targeting factors or processing enzymes engage nascent chains. (3) Application of ribosome profiling to define the protein coding potential of complex genomes. (4) The development of a proximity-specific ribosome profiling assay for monitoring subcellular localized translation and its use to follow translation on the surface of the endoplasmic reticulum and mitochondria.

Citation Format: Jonathan Weissman. Monitoring translation in space and time with ribosome profiling. [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 IA20.