2-Bromopalmitate depletes lipid droplets to inhibit viral replication

The global impact of emerging viral infections emphasizes the urgent need for effective broad-spectrum antivirals. The cellular organelle, lipid droplet (LD), is utilized by many types of viruses for replication, but its reduction does not affect cell survival. Therefore, LD is a potential target for developing broad-spectrum antivirals. In this study, we found that 2-bromopalmitate (2 BP), a previously defined palmitoylation inhibitor, depletes LD across all studied cell lines and exerts remarkable antiviral effects on different coronaviruses. We comprehensively utilized 2 BP, alongside other palmitoylation inhibitors such as cerulenin and 2-fluoro palmitic acid (2-FPA), as well as the enhancer palmostatin B and evaluated their impact on LD and the replication of human coronaviruses (hCoV-229E, hCoV-Oc43) and murine hepatitis virus (MHV-A59) at non-cytotoxic concentrations. While cerulenin and 2-FPA exhibited moderate inhibition of viral replication, 2 BP exhibited a much stronger suppressive effect on MHV-A59 replication, although they share similar inhibitory effects on palmitoylation. As expected, palmostatin B significantly enhanced viral replication, it failed to rescue the inhibitory effects of 2 BP, whereas it effectively counteracted the effects of cerulenin and 2-FPA. This suggests that the mechanism that 2 BP used to inhibit viral replication is beyond palmitoylation inhibition. Further investigations unveil that 2 BP uniquely depletes LDs, a phenomenon not exhibited by 2-FPA and cerulenin. Importantly, the depletion of LDs was closely associated with the inhibition of viral replication because the addition of oleic acid to 2 BP significantly rescued LD depletion and its inhibitory effects on MHV-A59. Our findings indicate that the inhibitory effects of 2 BP on viral replication primarily stem from LD disruption rather than palmitoylation inhibition. Intriguingly, fatty acid (FA) assays demonstrated that 2 BP reduces the FA level in mitochondria while concurrently increasing FA levels in the cytoplasm. These results highlight the crucial role of LDs in viral replication and uncover a novel biological activity of 2 BP. These insights contribute to the development of broad-spectrum antiviral strategies.

IMPORTANCE

In our study, we conducted a comparative investigation into the antiviral effects of palmitoylation inhibitors including 2-bromopalmitate (2-BP), 2-fluoro palmitic acid (2-FPA), and cerulenin. Surprisingly, we discovered that 2-BP has superior inhibitory effects on viral replication compared to 2-FPA and cerulenin. However, their inhibitory effects on palmitoylation were the same. Intrigued by this finding, we delved deeper into the underlying mechanism of 2-BP's potent antiviral activity, and we unveiled a novel biological activity of 2-BP: depletion of lipid droplets (LDs). Importantly, we also highlighted the crucial role of LDs in viral replication. Our insights shed new light on the antiviral mechanism of LD depletion paving the way for the development of broad-spectrum antiviral strategies by targeting LDs.

Structure-Guided Mutagenesis Targeting Interactions between pp150 Tegument Protein and Small Capsid Protein Identify Five Lethal and Two Live Attenuated HCMV Mutants

Human cytomegalovirus (HCMV) replication relies on a nucleocapsid coat of the 150kDa, subfamily-specific tegument phosphoprotein (pp150) to regulate cytoplasmic virion maturation. While recent structural studies revealed pp150-capsid interactions, the role of specific amino-acids involved in these interactions have not been established experimentally. In this study, pp150 and the small capsid protein (SCP), one of pp150's binding partners found atop the major capsid protein (MCP), were subjected to mutational and structural analyses. Mutations to clusters of polar or hydrophobic residues along the pp150-SCP interface abolished viral replication, with no replication detected in mutant virus-infected cells. Notably, a single point mutation at the pp150-MCP interface significantly attenuated viral replication, unlike the situation of pp150-deletion mutation where capsids degraded outside host nuclei. These functionally significant mutations targeting pp150-capsid interactions, particularly the pp150 K255E replication-attenuated mutant, can be explored to overcome the historical challenges of developing effective antivirals and vaccines against HCMV infection.

Lipid Droplets: Formation, Degradation, and Their Role in Cellular Responses to Flavivirus Infections

Lipid droplets (LDs) are cellular organelles derived from the endoplasmic reticulum (ER), serving as lipid storage sites crucial for maintaining cellular lipid homeostasis. Recent attention has been drawn to their roles in viral replication and their interactions with viruses. However, the precise biological functions of LDs in viral replication and pathogenesis remain incompletely understood. To elucidate the interaction between LDs and viruses, it is imperative to comprehend the biogenesis of LDs and their dynamic interactions with other organelles. In this review, we explore the intricate pathways involved in LD biogenies within the cytoplasm, encompassing the uptake of fatty acid from nutrients facilitated by CD36-mediated membranous protein (FABP/FATP)-FA complexes, and FA synthesis via glycolysis in the cytoplasm and the TCL cycle in mitochondria. While LD biogenesis primarily occurs in the ER, matured LDs are intricately linked to multiple organelles. Viral infections can lead to diverse consequences in terms of LD status within cells post-infection, potentially involving the breakdown of LDs through the activation of lipophagy. However, the exact mechanisms underlying LD destruction or accumulation by viruses remain elusive. The significance of LDs in viral replication renders them effective targets for developing broad-spectrum antivirals. Moreover, considering that reducing neutral lipids in LDs is a strategy for anti-obesity treatment, LD depletion may not pose harm to cells. This presents LDs as promising antiviral targets for developing therapeutics that are minimally or non-toxic to the host.

Endoplasmic reticulum-associated SARS-CoV-2 ORF3a elicits heightened cytopathic effects despite robust ER-associated degradation

IMPORTANCE

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has tragically claimed millions of lives through coronavirus disease 2019 (COVID-19), and there remains a critical gap in our understanding of the precise molecular mechanisms responsible for the associated fatality. One key viral factor of interest is the SARS-CoV-2 ORF3a protein, which has been identified as a potent inducer of host cellular proinflammatory responses capable of triggering the catastrophic cytokine storm, a primary contributor to COVID-19-related deaths. Moreover, ORF3a, much like the spike protein, exhibits a propensity for frequent mutations, with certain variants linked to the severity of COVID-19. Our previous research unveiled two distinct types of ORF3a mutant proteins, categorized by their subcellular localizations, setting the stage for a comparative investigation into the functional and mechanistic disparities between these two types of ORF3a variants. Given the clinical significance and functional implications of the natural ORF3a mutations, the findings of this study promise to provide invaluable insights into the potential roles undertaken by these mutant ORF3a proteins in the pathogenesis of COVID-19.

Insights into the Transcriptome of Human Cytomegalovirus: A Comprehensive Review

Human cytomegalovirus (HCMV) is a widespread pathogen that poses significant risks to immunocompromised individuals. Its genome spans over 230 kbp and potentially encodes over 200 open-reading frames. The HCMV transcriptome consists of various types of RNAs, including messenger RNAs (mRNAs), long non-coding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs), with emerging insights into their biological functions. HCMV mRNAs are involved in crucial viral processes, such as viral replication, transcription, and translation regulation, as well as immune modulation and other effects on host cells. Additionally, four lncRNAs (RNA1.2, RNA2.7, RNA4.9, and RNA5.0) have been identified in HCMV, which play important roles in lytic replication like bypassing acute antiviral responses, promoting cell movement and viral spread, and maintaining HCMV latency. CircRNAs have gained attention for their important and diverse biological functions, including association with different diseases, acting as microRNA sponges, regulating parental gene expression, and serving as translation templates. Remarkably, HCMV encodes miRNAs which play critical roles in silencing human genes and other functions. This review gives an overview of human cytomegalovirus and current research on the HCMV transcriptome during lytic and latent infection.

Syncytial and Congregative Effects of Dengue and Zika Viruses on the Aedes Albopictus Cell Line Differ among the Viral Strains

Objective

Dengue viruses (DENV) and Zika viruses (ZIKV) are transmitted from human to human or from non-human primates to humans by mosquito biting, so the viral interaction with mosquito cells is one key step within the viral life cycle. Therefore, our objective is to know how DENV or ZIKV interacts with mosquito cells.

Methods

Immunofluorescence assay and a direct visualization system are combined to monitor the syncytial or congregative effects of DENVs and ZIKVs on C6/36 cells. we studied the cytopathic effects of DENVs and ZIKVs on the mosquito cells, C6/36 which are widely used in the laboratory for the infections of DENV and ZIKV.

Results

Our results show that all strains of DENV-1 and DENV-2, most DENV-4 and some DENV-3 strains caused syncytial effects on C6/36 cells, while some DENV-3 and DENV-4 strains, and all the tested ZIKV strains caused cell congregation after infection but no cell fusion. In addition, we detected a range of pH environments from 6.0 to 8.0 that support the virus-caused cell fusion and figured out that the optimal pH condition is 7.5 at which the viral production is also the best. Furthermore, viral replication may be required for DENV's syncytial effects on C6/36 cells because the UV-inactivated virus failed to cause cell fusion.

Conclusion

Syncytial and congregative effects of DENV and ZIKV on the Aedes albopictus cells differ among the viral strains. Syncytial effects of DENV on C6/36 are important for viral replication.

A novel diG motif in ORF3a protein of SARS-Cov-2 for intracellular transport

The ongoing SARS-CoV-2/COVID-19 pandemic caused a global public health crisis. Yet, everyone's response to SARS-CoV-2 infection varies, and different viral variants confer diverse pathogenicity. Thus, it is imperative to understand how viral determinants contribute to COVID-19. Viral ORF3a protein is one of those viral determinants, as its functions are linked to induction of cell and tissues damages, disease severity and cytokine storm that is a major cause of COVID-19-related death. ORF3a is a membrane-associated protein. Upon synthesis, it is transported from endoplasmic reticulum, Golgi apparatus to plasma membrane and subcellular endomembranes including endosomes and lysosomes. However, how ORF3a is transported intracellularly remains elusive. The goal of this study was to carry out a systematic mutagenesis study to determine the structural relationship of ORF3a protein with its subcellular locations. Single amino acid (aa) and deletion mutations were generated in the putative function-relevant motifs and other regions of interest. Immunofluorescence and ImageJ analyses were used to determine and quantitate subcellular locations of ORF3a mutants in comparison with wildtype ORF3a. The wildtype ORF3a localizes predominantly (Pearson's coefficients about 0.8) on the membranes of endosomes and lysosomes. Consistent with earlier findings, deletion of the YXXΦ motif, which is required for protein export, retained ORF3a in the Golgi apparatus. Interestingly, mutations in a double glycine (diG) region (aa 187-188) displayed a similar phenotype to the YXXΦ deletion, implicating a similar role of the diG motif in intracellular transport. Indeed, interrupting any one of the two glycine residues such as deletion of a single (dG188), both (dG187/dG188) or substitution (G188Y) of these residues led to ORF3a retention in the Golgi apparatus (Pearson's coefficients ≥0.8). Structural analyses further suggest that the diG motif supports a type-II β-turn between the anti-parallel β4 and β5 sheets and connects to the YXXΦ motif via hydrogen bonds between two monomers. The diG- YXXΦ interaction forms a hand-in-hand configuration that could facilitate dimerization. Together, these observations suggest a functional role of the diG motif in intracellular transport of ORF3a.

Circular RNA profiling reveals abundant and diverse circRNAs of SARS-CoV-2, SARS-CoV and MERS-CoV origin

Circular RNAs (circRNAs) encoded by DNA genomes have been identified across host and pathogen species as parts of the transcriptome. Accumulating evidences indicate that circRNAs play critical roles in autoimmune diseases and viral pathogenesis. Here we report that RNA viruses of the Betacoronavirus genus of Coronaviridae , SARS-CoV-2, SARS-CoV and MERS-CoV, encode a novel type of circRNAs. Through de novo circRNA analyses of publicly available coronavirus-infection related deep RNA-Sequencing data, we identified 351, 224 and 2,764 circRNAs derived from SARS-CoV-2, SARS-CoV and MERS-CoV, respectively, and characterized two major back-splice events shared by these viruses. Coronavirus-derived circRNAs are more abundant and longer compared to host genome-derived circRNAs. Using a systematic strategy to amplify and identify back-splice junction sequences, we experimentally identified over 100 viral circRNAs from SARS-CoV-2 infected Vero E6 cells. This collection of circRNAs provided the first line of evidence for the abundance and diversity of coronavirus-derived circRNAs and suggested possible mechanisms driving circRNA biogenesis from RNA genomes. Our findings highlight circRNAs as an important component of the coronavirus transcriptome.

Summary

We report for the first time that abundant and diverse circRNAs are generated by SARS-CoV-2, SARS-CoV and MERS-CoV and represent a novel type of circRNAs that differ from circRNAs encoded by DNA genomes.

Rapid Neutralization Testing System for Zika Virus Based on an Enzyme-Linked Immunospot Assay

Zika virus (ZIKV) is a mosquito-borne flavivirus that has been associated with neuropathology in fetuses and adults, imposing a serious health concern. Therefore, the development of a vaccine is a global health priority. Notably, neutralization tests have a significant value for vaccine development and virus diagnosis. The cytopathic effect (CPE)-based neutralization test (Nt-CPE) is a common neutralization method for ZIKV. However, this method has some drawbacks, such as being time-consuming and labor-intensive and having low-throughput, which precludes its application in the detection of large numbers of specimens. To improve this problem, we developed a neutralization test based on an enzyme-linked immunospot assay (Nt-ELISPOT) for ZIKV and performed the assay in a 96-well format. A monoclonal antibody (mAb), 11C11, with high affinity and reactivity to ZIKV was used to detect ZIKV-infected cells. To optimize this method, the infectious dose of ZIKV was set at a multiplicity of infection (MOI) of 0.0625, and a detection experiment was performed after incubating for 24 h. As a result, under these conditions, the Nt-ELISPOT had good consistency with the traditional Nt-CPE to measure neutralizing titers of sera and neutralizing antibodies. Additionally, three neutralizing antibodies against ZIKV were screened by this method. Overall, we successfully developed an efficient neutralization test for ZIKV that is high-throughput and rapid. This Nt-ELISPOT can potentially be applied to detecting neutralizing titers of large numbers of specimens in vaccine evaluation and neutralizing antibody screening for ZIKV.

Zika virus increases mind bomb 1 levels, causing degradation of pericentriolar material 1 (PCM1) and dispersion of PCM1-containing granules from the centrosome

The centrosome is a cytoplasmic nonenveloped organelle functioning as one of the microtubule-organizing centers and composing a centriole center surrounded by pericentriolar material (PCM) granules. PCM consists of many centrosomal proteins, including PCM1 and centrosomal protein 131 (CEP131), and helps maintain centrosome stability. Zika virus (ZIKV) is a flavivirus of the family Flaviviridae whose RNA and viral particles are replicated in the cytoplasm. However, how ZIKV interacts with host cell components during its productive infection stage is incompletely understood. Here, using several primate cell lines, we report that ZIKV infection disrupts and disperses the PCM granules. We demonstrate that PCM1- and CEP131-containing granules are dispersed in ZIKV-infected cells, whereas the centrioles remain intact. We found that ZIKV does not significantly alter cellular skeletal proteins, and, hence, these proteins may not be involved in the interaction between ZIKV and centrosomal proteins. Moreover, ZIKV infection decreased PCM1 and CEP131 protein, but not mRNA, levels. We further found that the protease inhibitor MG132 prevents the decrease in PCM1 and CEP131 levels and centriolar satellite dispersion. Therefore, we hypothesized that ZIKV infection induces proteasomal PCM1 and CEP131 degradation and thereby disrupts the PCM granules. Supporting this hypothesis, we show that ZIKV infection increases levels of mind bomb 1 (MIB1), previously demonstrated to be an E3 ubiquitin ligase for PCM1 and CEP131 and that ZIKV fails to degrade or disperse PCM in MIB1-ko cells. Our results imply that ZIKV infection activates MIB1-mediated ubiquitination that degrades PCM1 and CEP131, leading to PCM granule dispersion.

Molecular cloning and characterization of the genes encoding the proteins of Zika virus

Zika virus (ZIKV) encodes a precursor protein (also called polyprotein) of about 3424 amino acids that is processed by proteases to generate 10 mature proteins and a small peptide. In the present study, we characterized the chemical features, suborganelle distribution and potential function of each protein using Flag-tagged protein expression system. Western blot analysis revealed the molecular weight of the proteins and the polymerization of E, NS1, and NS3 proteins. In addition, we performed multi-labeled fluorescent immunocytochemistry and subcellular fractionation to determine the subcellular localization of these proteins in host cells. We found that 1) the capsid protein colocalizes with 3 different cellular organelles: nucleoli, Golgi apparatus, and lipid droplet; NS2b and NS4a are associated with the Golgi apparatus; 2) the capsid and NS1proteins distribute in both cytoplasm and nucleus, NS5 is a nuclear protein; 3) NS3 protein colocalizes with tubulin and affects Lamin A; 4) Envelope, PrM, and NS2a proteins co-localize with the endoplasmic reticulum; 5) NS1 is associated with autophagosomes and NS4b is related to early endosome; 6) NS5 forms punctate structures in the nucleus that associate with splicing compartments shown by SC35, leading to reduction of SC35 protein level and trafficking of SC35 from the nucleus to the cytoplasm. These data suggest that ZIKV generates 10 functional viral proteins that exhibit distinctive subcellular distribution in host cells.

Abstract C19: Molecular biology of lung cancer in Puerto Ricans

Lung cancer is a leading cancer killer, lung adenocarcinoma (AC) being its most common type. Several studies suggest that the frequency or nature of genetic events driving AC differ among ethnic populations. These differences impact treatment decisions as targeted agents are under development for a number of genes that drive lung cancer. For example, mutations in the epidermal growth factor receptor (EGFR) represent a driving event in a substantial number of AC patients that can be targeted with tyrosine kinase inhibitors. With the funding of a U54 Partnership grant between the Ponce School of Medicine in Ponce, PR and the Moffitt Cancer Center in Tampa, Florida we are constructing a molecular database for Puerto Rican Lung Cancer patients. Sample collection includes acquisition of fresh frozen and paraffin-embedded tissues via the U54-funded Puerto Rico tissue bank. DNA analysis of these tissues includes ancestry markers and exome sequencing of genes commonly altered in AC, including KRAS, TP53, EGFR, STK11, CDKN1C and RB1. Initial results suggest that the frequency of KRAS mutations in this population are significantly lower than those seen in a white mainland cohort, whereas the rate of EGFR and STK11 mutations is elevated. Since both EFGR and STK11 are potentially targetable mutations these data suggest that Puerto Rican AC patients would greatly benefit from genetic screening. Our U54 project also probes the role of the retinoblastoma protein (Rb) in lung cancer. Rb was the first tumor suppressor to be discovered, and yet its potency as a tumor suppressor remains only partially explained. We are interested in characterizing how Rb loss contributes to the aggressiveness of small cell lung carcinomas (SCLC). SCLC are poorly differentiated tumors with early proclivity for metastasis. Prognosis is poor with only 10-20% of patients achieving long-term disease-free intervals. Still, SCLC aggressivity remains to be molecularly explained. Interestingly, SCLC show high rates of Rb inactivation, which led us to hypothesize that in SCLC, Rb loss during early tumorigenesis facilitates both over-proliferation and early metastasis. Supporting our hypothesis, we found that the Rb-deficient SCLC cell line H187 lacks expression of E-cadherin while overexpressing N-cadherin, relative to Rb-expressing non-small cell lung carcinoma cell lines H1666 and H1650. We confirmed the Rb-positive status of H1666 and H1650 and the Rb-negative status of H187 by immunoblot. These results suggest that Rb loss in lung cancer cell lines provokes a cadherin switch indicative of an epithelial-to-mesenchymal transition. Consistently, we found overexpression of the mesenchymal marker vimentin in H187 relative to H1666 and H1650. When compared to H1666 and H1650, H187 lacked expression of the adherens junction component α-catenin and of the cytoskeletal adapter Eplin. Furthermore, H187 cells show up-regulated levels of Pak1, a Rac1 and Cdc42 effector whose up-regulation is associated to adherens junction disruption. Tiam-1, a Rac1 and Cdc42 activator, is also up-regulated in H187 relative to H1666 and H1650. Together, our data in lung cell lines suggests that Rb loss results in adherens junction alterations possibly due to transcriptional alteration of cell adhesion genes, aberrant regulation of the Rho GTPases Rac1 and Cdc42, and disruption of the cortical cytoskeleton. Based on our data, we propose that Rb loss in SCLC, not only leads to an increased proliferative capacity during early tumorigenesis, but also exacerbates early tumor aggressiveness by perturbing cellular adhesion, which facilitates tumor cell detachment and metastasis. Our ultimate goal is to link the genetic alterations we found in Puerto Ricans to Rb function, cell adhesion, and tumor aggressivity.

Citation Format: Pedro G. Santiago-Cardona, Brienne E. Engel, Jonathan González-Flores, Ruth Cruz-Cosme, Teresita Muñoz-Antonia, W. Douglas Cress. Molecular biology of lung cancer in Puerto Ricans. [abstract]. In: Proceedings of the Sixth AACR Conference: The Science of Cancer Health Disparities; Dec 6–9, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2014;23(11 Suppl):Abstract nr C19. doi:10.1158/1538-7755.DISP13-C19

Abstract C12: Molecular mechanisms of aggressiveness of Rb-deficient tumors

Osteosarcomas (OS) and small cell lung carcinomas (SCLC) are poorly differentiated, highly aggressive tumors, with an early proclivity to metastasize. Prognosis is poor for both, with only 10-20% of patients achieving long-term disease-free intervals. Still, OS and SCLC aggressivity remain to be molecularly explained. Interestingly, these cancer types show high rates of inactivation of the RB1 gene coding for the retinoblastoma protein (Rb), a known cell cycle repressor. This observation led us to hypothesize that in OS and SCLC, Rb loss during early tumorigenesis facilitates both increased proliferation and an early tendency for metastasis. Supporting our hypothesis, our previous studies in osteoblasts showed that Rb transcriptionally regulates a wide repertoire of cell adhesion genes, including those coding for adherens junction cadherins and integrins. We also found that adhrens junction assembly requires the Rb-dependent transcriptional repression of Pak1, a Rac1-binding kinase that destabilizes cell adhesion when up-regulated. Thus, the early proclivity for metastasis of OS and SCLC may be related to perturbations in cell adhesion due to Rb loss.

Here we present new data using the SCLC line H187 and the non-small cell lung carcinoma (NSCLC) cell lines H1975 and H520. SCLC carcinomas have high rates (> 90%) of Rb loss while NSCLC are known to be Rb wild type. Therefore, comparing H1975 and H520 vs. H187 provided us with an Rb-proficient vs. Rb-deficient system similar to the one we previously used to study Rb-engendered effects in osteoblasts. Our immunoblots and qRT-PCR showed that the Rb-null H187 cells expressed dramatically reduced levels of E-cadherin mRNA and protein relative to H1975 and H520, confirming that Rb loss impairs cell adhesion due to adherens junction loss. Interestingly, N-cadherin is up-regulated in H187 cells, suggesting that Rb loss triggers a cadherin switch similar to the one associated with epithelial-to-mesenchymal transitions. Other cell adhesion-related genes we found down-regulated in Rb-null H187 cells relative to H1975 and H520, as determined by qRT-PCR, were α-catenin, β-catenin, OB-cadherin, and the cytoskeletal adapter proteins eplin, vinculin, formin-1, and α-actinin. Our immunoblots also showed decreased levels of merlin, an adherens junction-interacting protein, in H187 cells. We also studied the expression of Rac1-binding proteins, given their involvement in cell adhesion. Our immunoblots and qRT-PCR showed reduced levels of IQGAP1 in H187 cells relative to H1975 and H520 cells. Given that IQGAP1 is a GTPase activating protein (GAP) that represses Rac1 by promoting its GDP-bound inactive state, we postulate that Rb represses Rac1 function via IQGAP1. Beta-2-chimaerin, another Rac1 GAP was also down regulated at the protein level in H187 cells. Taken together, our data in lung cell lines recapitulate most of our findings in osteoblasts, both in regards to the effect of Rb on cell adhesion and to the need for the Rb-mediated repression of Rac1 for the establishment of cell adhesion. Based on our data, we propose that Rb loss in OS and SCLC, not only leads to an increased proliferative capacity during early tumorigenesis, but also exacerbates aggressiveness of tumors at early stages by perturbing cellular adhesion, which in turn facilitates tumor cell detachment and metastasis.

Citation Format: Jonathan González-Flores, Ruth Cruz-Cosme, Yariana Rodríguez-Ortiz, Sarah Brady, Ricardo Fraticelli-Rosado, Brienne Engel, Douglas Cress, Pedro G. Santiago-Cardona. Molecular mechanisms of aggressiveness of Rb-deficient tumors. [abstract]. In: Proceedings of the Third AACR International Conference on Frontiers in Basic Cancer Research; Sep 18-22, 2013; National Harbor, MD. Philadelphia (PA): AACR; Cancer Res 2013;73(19 Suppl):Abstract nr C12.