Identification of the heterogeneous nuclear ribonucleoprotein A2/B1 as the antigen for the gastrointestinal cancer specific monoclonal antibody MG7

Lee, Chi-ho; Lum, John Hon-Kei; Cheung, Belinda Pik-yuen; Wong, Man Sau; Butt, Yoki Kwok‐Chu; Tam, Ming F.; Chan, Wai-Yee; Chow, Chit; Hui, Pui Wah; Kwok, Francis; Lo, Samuel Chun‐Lap; Fan, Daiming

doi:10.1002/pmic.200401159

Cited by 42 publications

(34 citation statements)

References 21 publications

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“…The ability of hnRNP A2 to shuttle between the nucleus and cytoplasm is required for mRNA processing (Nichols et al, 2000). Increased nuclear translocation of this protein has been reported in cells undergoing transformation in various tumors (Lee et al, 2005). hnRNP A2 is a component of this respiratory stress pathway that induces highly invasive phenotypes (Amuthan et al, 2001(Amuthan et al, , 2002Guha et al, 2007;Biswas et al, 2008a).…”

Section: Discussionmentioning

confidence: 99%

Heterogeneous Nuclear Ribonucleoprotein A2 Is a Common Transcriptional Coactivator in the Nuclear Transcription Response to Mitochondrial Respiratory Stress

Guha

Pan

Fang

et al. 2009

MBoC

100

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Mitochondrial dysfunction and altered transmembrane potential initiate a mitochondrial respiratory stress response, also known as mitochondrial retrograde response, in a wide spectrum of cells. The mitochondrial stress response activates calcineurin, which regulates transcription factors, including a new nuclear factor-B (NF-B) pathway, different from the canonical and noncanonical pathways. In this study using a combination of small interfering RNA-mediated mRNA knock down, transcriptional analysis, and chromatin immunoprecipitation, we report a common mechanism for the regulation of previously established stress response genes Cathepsin L, RyR1, and Glut4. Stress-regulated transcription involves the cooperative interplay between NF-B (cRel: p50), C/EBP␦, cAMP response element-binding protein, and nuclear factor of activated T cells. We show that the functional synergy of these factors requires the stress-activated heterogeneous nuclear ribonucleoprotein (hnRNP) A2 as a coactivator. HnRNP A2 associates with the enhanceosome, mostly through protein-protein interactions with DNA-bound factors. Silencing of hnRNP A2 as well as other DNA binding signature factors prevents stress-induced transcriptional activation and reverses the invasiveness of mitochondrial DNA-depleted C2C12 cells. Induction of mitochondrial stress signaling by electron transfer chain inhibitors also involved hnRNPA2 activation. We describe a common mechanism of mitochondrial respiratory stress-induced activation of nuclear target genes that involves hnRNP A2 as a transcription coactivator. INTRODUCTIONMitochondrial biogenesis requires a coordinated interplay between proteins encoded by the nuclear and mitochondrial genomes. At least two different mechanisms have been described for the intergenomic cross-talk between these spatially separated genetic systems: anterograde and retrograde signaling (Liao et al., 1991;Liu and Butow, 2006). The anterograde intergenomic regulatory circuit involves nonmitochondrial signals that activate nuclear transcription factors to regulate both nuclear and mitochondrial gene expression (Poyton and McEwen, 1996;Kelly and Scarpulla, 2004;Spiegelman, 2007). The role of peroxisome proliferator-activated receptor ␥ coactivator-1 family of coactivator proteins in mitochondrial biogenesis and respiration is an example of this type of regulation (Puigserver et al., 1998). Regulation of cellular respiration by reduced mammalian target of rapamycin signaling probably represents another example of anterograde signaling (Bonawitz et al., 2007). In contrast, the retrograde intergenomic regulatory circuit involves the regulation of nuclear gene expression by mitochondrial stress signals that are initiated by metabolic stress, respiratory changes, or mitochondrial DNA damage (Liao and Butow, 1993;Jia et al., 1997;Biswas et al., 1999;Liu et al., 2001;Amuthan et al., 2002;Butow and Avadhani, 2004;Liu and Butow, 2006).The mammalian retrograde pathway is initiated by disruption of mitochondrial membrane potential (⌬⌿ m ), which can ...

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Section: Discussionmentioning

confidence: 99%

Heterogeneous Nuclear Ribonucleoprotein A2 Is a Common Transcriptional Coactivator in the Nuclear Transcription Response to Mitochondrial Respiratory Stress

Guha

Pan

Fang

et al. 2009

MBoC

100

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“…In addition, hnRNP A2 participates in virtually all aspects of mRNA processing, including packaging of nascent transcripts, splicing of pre-mRNAs, and translational regulation (16), and plays crucial roles in posttranscriptional regulation by shuttling between the nucleus and the cytoplasm with mRNA (8). hnRNP A2 also participates in telomere biogenesis, and its overexpression has been described for many cancer cell lines derived from the breast, pancreas, liver, and gastrointestinal tract (30,31,72,75). In virus infections, hnRNP A2 has been shown to enhance mouse hepatitis virus RNA synthesis (60) and to regulate the trafficking of genomic RNA of human immunodeficiency virus (33).…”

Section: Discussionmentioning

confidence: 99%

Heterogeneous Nuclear Ribonucleoprotein A2 Participates in the Replication of Japanese Encephalitis Virus through an Interaction with Viral Proteins and RNA

Katoh

Mori

Kambara

et al. 2011

J Virol

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Japanese encephalitis virus (JEV) is a mosquito-borne flavivirus that is kept in a zoonotic transmission cycle between pigs and mosquitoes. JEV causes infection of the central nervous system with a high mortality rate in dead-end hosts, including humans. Many studies have suggested that the flavivirus core protein is not only a component of nucleocapsids but also an important pathogenic determinant. In this study, we identified heterogeneous nuclear ribonucleoprotein A2 (hnRNP A2) as a binding partner of the JEV core protein by pulldown purification and mass spectrometry. Reciprocal coimmunoprecipitation analyses in transfected and infected cells confirmed a specific interaction between the JEV core protein and hnRNP A2. Expression of the JEV core protein induced cytoplasmic retention of hnRNP A2 in JEV subgenomic replicon cells. Small interfering RNA (siRNA)-mediated knockdown of hnRNP A2 resulted in a 90% reduction of viral RNA replication in cells infected with JEV, and the reduction was cancelled by the expression of an siRNA-resistant hnRNP A2 mutant. In addition to the core protein, hnRNP A2 also associated with JEV nonstructural protein 5, which has both methyltransferase and RNA-dependent RNA polymerase activities, and with the 5-untranslated region of the negative-sense JEV RNA. During one-step growth, synthesis of both positive-and negativestrand JEV RNAs was delayed by the knockdown of hnRNP A2. These results suggest that hnRNP A2 plays an important role in the replication of JEV RNA through the interaction with viral proteins and RNA.Japanese encephalitis virus (JEV) belongs to the genus Flavivirus within the family Flaviviridae. Members of the genus Flavivirus are predominantly arthropod-borne viruses, such as dengue virus (DEN), West Nile virus (WNV), yellow fever virus (YFV), and tick-borne encephalitis virus, and frequently cause significant morbidity and mortality in mammals and birds (46). JEV is distributed in the south and southeast regions of Asia and is kept in a zoonotic transmission cycle between pigs or birds and mosquitoes (46,69). JEV spreads to dead-end hosts, including humans, through the bite of JEVinfected mosquitoes and causes infection of the central nervous system, with a high mortality rate (46). JEV has a singlestranded positive-strand RNA genome of approximately 11 kb, which is capped at the 5Ј end but lacks modification of the 3Ј terminus by polyadenylation (38). The genomic RNA carries a single large open reading frame, and a polyprotein translated from the genome is cleaved co-and posttranslationally by host and viral proteases to yield three structural proteins-the core, precursor membrane, and envelope protein-and seven nonstructural (NS) proteins-NS1, NS2A, NS2B, NS3, NS4A, NS4B, and NS5 (61).The core protein of flaviviruses has RNA-binding activity through basic amino acid clusters located in both the amino and carboxyl termini, indicating that the core protein forms a nucleocapsid interacting with viral RNA (23). In spite of the replication of flaviviruses in the cyto...

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“…High levels of hnRNP A2/B1 expression also colocalized with areas of genetic injury, as assessed by microsatellite instability and loss of heterozygosity (17). hnRNP A2/B1 has been consistently reported as an informative biomarker for lung cancer screening using a variety of analytic approaches, including expression studies and proteomic analysis (7,8,18,19). We have also previously reported that hnRNP A2/B1 expression is tightly controlled during lung development (20).…”

Section: Introductionmentioning

confidence: 96%

“…The hnRNPs are a complex group of RNA-binding proteins that play a key role in mRNA processing and telomere biogenesis (1)(2)(3)(4). hnRNP A2/B1 overexpression has been described in many cancers, including breast, pancreas, liver, and gastrointestinal cell lines (5)(6)(7)(8). Recent reports have described a critical role of hnRNP A2/B1 in the regulation of fundamental biology especially related to cancer, such as migration (9) and aerobic glycolysis (10).…”

Section: Introductionmentioning

confidence: 99%

hnRNP A2/B1 Modulates Epithelial-Mesenchymal Transition in Lung Cancer Cell Lines

et al. 2010

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Heterogeneous nuclear ribonucleoprotein A2/B1 (hnRNP A2/B1) has been reported to be overexpressed in lung cancer and in other cancers such as breast, pancreas, and liver. However, a mechanism linking hnRNP A2/ B1 overexpression and progression to cancer has not yet been definitively established. To elucidate this mechanism, we have silenced hnRNPA2/B1 mRNA in non-small-cell lung cancer cell lines A549, H1703, and H358. These cell lines present different levels of expression of epithelial-to-mesenchymal transition (EMT) markers such as E-cadherin, fibronectin, and vimentin. Microarray expression analysis was performed to evaluate the effect of silencing hnRNP A2/B1 in A549 cells. We identified a list of target genes, affected by silencing of hnRNP A2/B1, that are involved in regulation of migration, proliferation, survival, and apoptosis. Silencing hnRNP A2/ B1 induced formation of cell clusters and increased proliferation. In the anchorage-independent assay, silencing hnRNP A2/B1 increased colony formation by 794% in A549 and 174% in H1703 compared with a 25% increase in proliferation, in both cell lines, in a two-dimensional proliferation assay. Silencing hnRNP A2/B1 decreased migration in intermediate cell line A549 and mesenchymal cell line H1703; however, no changes in proliferation were observed in epithelial cell line H358. Silencing hnRNP A2/B1 in A549 and H1703 cells correlated with an increase of E-cadherin expression and downregulation of the E-cadherin inhibitors Twist1 and Snai1. These data suggest that expression of hnRNP A2/B1 may play a role in EMT, in nonepithelial lung cancer cell lines A549 and H1703, through the regulation of E-cadherin expression.

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Identification of the heterogeneous nuclear ribonucleoprotein A2/B1 as the antigen for the gastrointestinal cancer specific monoclonal antibody MG7

Cited by 42 publications

References 21 publications

Heterogeneous Nuclear Ribonucleoprotein A2 Is a Common Transcriptional Coactivator in the Nuclear Transcription Response to Mitochondrial Respiratory Stress

Heterogeneous Nuclear Ribonucleoprotein A2 Is a Common Transcriptional Coactivator in the Nuclear Transcription Response to Mitochondrial Respiratory Stress

Heterogeneous Nuclear Ribonucleoprotein A2 Participates in the Replication of Japanese Encephalitis Virus through an Interaction with Viral Proteins and RNA

hnRNP A2/B1 Modulates Epithelial-Mesenchymal Transition in Lung Cancer Cell Lines

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