hnRNP B1 Research Articles

Genome-Wide Analysis of Heterogeneous Nuclear Ribonucleoprotein (hnRNP) Binding to HIV-1 RNA Reveals a Key Role for hnRNP H1 in Alternative Viral mRNA Splicing.

Alternative splicing of HIV-1 mRNAs increases viral coding potential and controls the levels and timing of gene expression. HIV-1 splicing is regulated in part by heterogeneous nuclear ribonucleoproteins (hnRNPs) and their viral target sequences, which typically repress splicing when studied outside their native viral context. Here, we determined the location and extent of hnRNP binding to HIV-1 mRNAs and their impact on splicing in a native viral context. Notably, hnRNP A1, hnRNP A2, and hnRNP B1 bound to many dispersed sites across viral mRNAs. Conversely, hnRNP H1 bound to a few discrete purine-rich sequences, a finding that was mirrored in vitro hnRNP H1 depletion and mutation of a prominent viral RNA hnRNP H1 binding site decreased the use of splice acceptor A1, causing a deficit in Vif expression and replicative fitness. This quantitative framework for determining the regulatory inputs governing alternative HIV-1 splicing revealed an unexpected splicing enhancer role for hnRNP H1 through binding to its target element.IMPORTANCE Alternative splicing of HIV-1 mRNAs is an essential yet quite poorly understood step of virus replication that enhances the coding potential of the viral genome and allows the temporal regulation of viral gene expression. Although HIV-1 constitutes an important model system for general studies of the regulation of alternative splicing, the inputs that determine the efficiency with which splice sites are utilized remain poorly defined. Our studies provide an experimental framework to study an essential step of HIV-1 replication more comprehensively and in much greater detail than was previously possible and reveal novel cis-acting elements regulating HIV-1 splicing.

Global profiling of hnRNP A2/B1-RNA binding on chromatin highlights LncRNA interactions

ABSTRACTLong noncoding RNAs (lncRNAs) often carry out their functions through associations with adaptor proteins. We recently identified heterogeneous ribonucleoprotein (hnRNP) A2/B1 as an adaptor of the human HOTAIR lncRNA. hnRNP A2 and B1 are splice isoforms of the same gene. The spliced version of HOTAIR preferentially associates with the B1 isoform, which we hypothesize contributes to RNA-RNA matching between HOTAIR and transcripts of target genes in breast cancer. Here we used enhanced cross-linking immunoprecipitation (eCLIP) to map the direct interactions between A2/B1 and RNA in breast cancer cells. Despite differing by only twelve amino acids, the A2 and B1 splice isoforms associate preferentially with distinct populations of RNA in vivo. Through cellular fractionation experiments we characterize the pattern of RNA association in chromatin, nucleoplasm, and cytoplasm. We find that a majority of interactions occur on chromatin, even those that do not contribute to co-transcriptional splicing. A2/B1 binding site locations on multiple RNAs hint at a contribution to the regulation and function of lncRNAs. Surprisingly, the strongest A2/B1 binding site occurs in a retained intron of HOTAIR, which interrupts an RNA-RNA interaction hotspot. In vitro eCLIP experiments highlight additional exonic B1 binding sites in HOTAIR which also surround the RNA-RNA interaction hotspot. Interestingly, a version of HOTAIR with the intron retained is still capable of making RNA-RNA interactions in vitro through the hotspot region. Our data further characterize the multiple functions of a repurposed splicing factor with isoform-biased interactions, and highlight that the majority of these functions occur on chromatin-associated RNA.

Mechanisms underlying regulation of cell cycle and apoptosis by hnRNP B1 in human lung adenocarcinoma A549 cells.

Overexpression of heterogeneous nuclear ribonucleoprotein B1 (hnRNP B1), a nuclear RNA binding protein, has been reported to occur in early-stage lung cancer and in premalignant lesions. DNA-dependent protein kinase (DNA-PK) is known to be involved in the repair of double-strand DNA breaks. Reduced capacity to repair DNA has been associated with the risk of lung cancer. We investigated a link between hnRNP B1 and DNA-PK and their effects on proliferation, cell cycle, and apoptosis in the human lung adenocarcinoma cell line A549. We found that hnRNP B1 and DNA-PK interact with each other in a complex fashion. Reducing hnRNP B1 expression in A549 cells with the use of RNAi led to upregulation of p53 activity through upregulation of DNA-PK activity but without inducing p53 expression. Further, suppression of hnRNP B1 in A549 cells slowed cell proliferation, promoted apoptosis, and induced cell cycle arrest at the G1 stage. The presence of NU7026 reduced the arrest of cells at the G1 stage and reduced the apoptosis rate while promoting cell growth. Taken together, our results demonstrate that by regulating DNA-PK activity, hnRNP B1 can affect p53-mediated cell cycle progression and apoptosis, resulting in greater cell survival and subsequent proliferation.

In-silico designing of hnRNP B1 inhibitors against lung cancer: a computational approach

RNA-binding proteins regulate the maturtarion of mRNA including pre-mRNA splicing, mRNA transport from the nucleus to cytoplasm, the translocation and longevity of transcripts within the cytoplasm as well as translation of the message. One key RNA-binding protein identified in several aspects of this process is heterogeneous ribonuclear ribonucleoprotein B1 (hnRNP B1) and it plays a role in several cellular functions. HnRNP B1 is overexpressed in several cancers including lung and squamous cell carcinoma of various organs, in addition, its mRNA can be detected in the serum of patients with early stage lung cancer and can therefore be used as a biomarker for cancer detection. Furthermore, it can be used as a target for treatment. In the present study hnRNP B1 was used as a target receptor for in silico ligand binding studies using a library of 55 small compounds selected from the current knowledge of lung cancer therapeutic drugs available in the market as well as known inhibitors of hnRNP B1. TSAR studies were carried out for selected compounds from BioMed CAChe to determine docking score and then compared with 7 lactate dehydrogenase inhibitor involved in lung cancer whose IC50 value were known. Results from both software analyses indicated that EGCG was a potent candidate ligand of hnRNP B1 and was selected as a parent compound for pharmacophore modifications to improve the binding affinity and activity against hnRNP B1. A library of 158 compounds was generated after modification of EGCG and molecular modeling and docking identified several analogues with increased binding scores. In addition, pharmacophore studies indicated the significant importance of ring D in EGCG and the formation of H-bonds between the modified ligands and amino acid GLU108 of hnRNPB1. Hence the outcomes of study identify a strategy for the identification of new lead molecules bearing drug-like properties. Future studies are required to validate this approach and measure the efficacy of analogues of compounds identified using in silico approaches.

AB0193 Antibodies to Hnrnp B1 (RA33) in Patients with Systemic Sclerosis

BackgroundSystemic sclerosis (SSc) is an autoimmune disease characterized by the occurrence of a wide range of autoantibodies (Aab) which can predict distinct clinical features of SSc. Aab to hnRNP A2...

Splicing factor hnRNP A2 activates the Ras-MAPK-ERK pathway by controlling A-Raf splicing in hepatocellular carcinoma development

In recent years, it has become clear that splicing factors play a direct role in cancer development. We showed previously that splicing factors SRSF1, SRSF6, and hnRNP A2/B1 are up-regulated in several cancers and can act as oncogenes when up-regulated. Here we examined the role of splicing factors hnRNP A1/A1b and hnRNP A2/B1 in hepatocellular carcinoma (HCC). We show that the splicing factors hnRNP A1 and hnRNP A2 are up-regulated in HCC tumors derived from inflammation-induced liver cancer mouse model. Overexpression of hnRNP A1 or hnRNP A2, but not the splicing isoform hnRNP B1, induced tumor formation of immortalized liver progenitor cells, while knockdown of these proteins inhibited anchorage-independent growth and tumor growth of human liver cancer cell lines. In addition, we found that cells overexpressing hnRNP A2 showed constitutive activation of the Ras-MAPK-ERK pathway. In contrast, knockdown of hnRNP A2 inhibited the Ras-MAPK-ERK pathway and prevented ERK1/2 activation by EGF. Moreover, we found that hnRNP A2 regulates the splicing of A-Raf, reducing the production of a short dominant-negative isoform of A-Raf and elevating the full-length A-Raf transcript. Taken together, our data suggest that hnRNP A2 up-regulation in HCC induces an alternative splicing switch that down-regulates a dominant-negative isoform of A-Raf, leading to activation of the Raf-MEK-ERK pathway and cellular transformation.

Mechanisms Underlying Regulation of Cell Cycle and Apoptosis by hnRNP B1 in Human Lung Adenocarcinoma A549 Cells

Mechanisms Underlying Regulation of Cell Cycle and Apoptosis by hnRNP B1 in Human Lung Adenocarcinoma A549 Cells

SPRi-Based Strategy to Identify Specific Biomarkers in Systemic Lupus Erythematosus, Rheumatoid Arthritis and Autoimmune Hepatitis

BackgroundHeterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 is a target for antinuclear autoantibodies in systemic Lupus erythematosus (SLE), rheumatoid arthritis (RA), and autoimmune hepatitis (AIH). AimTo monitor molecular interactions between peptides spanning the entire sequence of hnRNP A2/B1 and sera from patients and healthy controls.MethodsSera from 8 patients from each pathology and controls were passed across a surface plasmon resonance Imagery (SPRi) surface containing 39 overlapping peptides of 17 mers covering the human hnRNP B1. Interactions involving the immobilised peptides were followed in real time and dissociation rate constants koff for each interaction were calculated.ResultsSeveral significant interactions were observed: i) high stability (lower koff values) between P55-70 and the AIH sera compared to controls (p= 0.003); ii) lower stability (higher koff values) between P118-133 and P262-277 and SLE sera, P145-160 and RA sera compared to controls (p=0.006, p=0.002, p=0.007). The binding curves and koff values observed after the formation of complexes with anti-IgM and anti-IgG antibodies and after nuclease treatment of the serum indicate that i) IgM isotypes are prevalent and ii) nucleic acids participate in the interaction between anti-hnRNAP B1 and P55-70 and also between controls and the peptides studied.ConclusionsThese results indicate that P55-70 of hnRNP B1 is a potential biomarker for AIH in immunological tests and suggest the role of circulating nucleic acids, (eg miRNA), present or absent according to the autoimmune disorders and involved in antigen-antibody stability.

Magnetic nanoparticle-enhanced SPR on gold nanoslits for ultra-sensitive, label-free detection of nucleic acid biomarkers

We have demonstrated a detection method for the ultra-sensitive detection of an mRNA biomarker. The method utilizes functionalized magnetic nanoparticles (MNPs) for signal enhancement in conjunction with surface plasmon resonance (SPR) on gold nanoslits. The approach for detection includes double hybridization at two different specific locations in two steps. First, the biomarker target molecule is captured with MNPs, and second, MNPs carrying the target molecule are introduced to the SPR chip to hybridize with probes immobilized on the gold nanoslits. In this work, MNPs were applied for a dual purpose: to isolate the target molecule from the sample matrix to prevent non-specific binding and to enhance the SPR response. Gold nanoslits that provide SPR sensing were fabricated by nanoimprinting lithography on polycarbonate (PC) film. The film was integrated with a microliter volume microfluidic chip to form the SPR detection chip. This detection method was used to detect mRNA heterogeneous nuclear ribonucleoproteins (hnRNP B1) in two cancer cell lines, CL1-0 and CL1-5. hnRNP B1 is an mRNA biomarker that is overexpressed in lung cancer tissue in the early stage of cancer and can be found in the serum and plasma of lung cancer patients. A synthetic target molecule and extracted total RNA from the cell lines were used as samples. Without amplification and labeling of the target molecule, the SPR results demonstrate a specific and sensitive method for the detection of hnRNP B1 mRNA in extracted RNA from the two selected cell lines. The method is capable of measuring down to 30 fM of the target molecule in a 7 μl sample (corresponding to 1.26 × 10(5) molecules) without amplification and labeling of the target molecule.

Surface Plasmon Resonance Imagery-based strategy to study hnRNPA2/B1 peptides as specific biomarkers in systemic lupus erythematosus, rheumatoid arthritis and autoimmune hepatitis

Event Abstract Back to Event Surface Plasmon Resonance Imagery-based strategy to study hnRNPA2/B1 peptides as specific biomarkers in systemic lupus erythematosus, rheumatoid arthritis and autoimmune hepatitis Elvire Beleoken1, 2, 3*, Herve Leh4, Eleonora De Martin3, Catherine Johanet1, 2, 5, Didier Samuel1, 2, 3, Jean-Charles Duclos-Vallee1, 2, 3, Malcolm Buckle4 and Eric Ballot1, 2, 5 1 Inserm, Unite 785, France 2 Univ Paris-Sud, Unité Mixte de Recherche en Santé 785, France 3 AP-HP Hopital Paul Brousse, France 4 Institut d'Alembert, Laboratoire de biologie et pharmacologie appliquée (LBPA), France 5 AP-HP, Hôpital Saint Antoine, France Heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1 is one of antinuclear autoantibodies targets in systemic lupus erythematosus (SLE), rheumatoid arthritis (RA), and autoimmune hepatitis (AIH). Aim. To monitor molecular interactions between peptides spanning the entire sequence of hnRNP and sera from patients and healthy controls. Methods. Sera from 8 patients from each pathology and controls were passed across a Surface Plasmon Resonance Imagery (SPRi) surface containing 39 overlapping peptides of 17 mers covering the human hnRNP B1. Interactions involving the immobilised peptides were followed in real time and the dissociation rate constant koff for each interaction were calculated. Results. Several significant interactions were observed: i) high stability (lower koff values) between P55-70 and the AIH sera compared to controls (p= 0.003); ii) less stability (higher koff values) between P118-133 and P262-277 and SLE sera, P145-160 and RA sera compared to controls (p=0.006, p=0.002, p=0.007). The binding curves and koff values observed after the formation of complexes with anti-IgM and anti-IgG antibodies and after nuclease treatment of the serum indicate that i) IgM isotypes are prevalent and ii) nucleic acids participate in the interaction between anti-hnRNAP B1 and P55-70 and also between controls and the peptides studied. Conclusions. These results indicate that P55-70 of hnRNP B1 is a potential biomarker for AIH in immunological tests and suggest the role of circulating nucleic acids, (eg miRNA), present or absent according to the autoimmune disorders and involved in antigen-antibody stability. Keywords: Autoimmune Hepatitis, SPRi (surface Plasmon resonance imagery), heterogeneous nuclear ribonucleoproteine A2/B1(hnRNP A2/B1), biomarkers, miRNA Conference: 15th International Congress of Immunology (ICI), Milan, Italy, 22 Aug - 27 Aug, 2013. Presentation Type: Abstract Topic: Immune receptors and signaling Citation: Beleoken E, Leh H, De Martin E, Johanet C, Samuel D, Duclos-Vallee J, Buckle M and Ballot E (2013). Surface Plasmon Resonance Imagery-based strategy to study hnRNPA2/B1 peptides as specific biomarkers in systemic lupus erythematosus, rheumatoid arthritis and autoimmune hepatitis. Front. Immunol. Conference Abstract: 15th International Congress of Immunology (ICI). doi: 10.3389/conf.fimmu.2013.02.00102 Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters. The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated. Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed. For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions. Received: 11 Mar 2013; Published Online: 22 Aug 2013. * Correspondence: Mrs. Elvire Beleoken, Inserm, Unite 785, Villejuif, France, documentaliste.chb@pbr.aphp.fr Login Required This action requires you to be registered with Frontiers and logged in. To register or login click here. Abstract Info Abstract The Authors in Frontiers Elvire Beleoken Herve Leh Eleonora De Martin Catherine Johanet Didier Samuel Jean-Charles Duclos-Vallee Malcolm Buckle Eric Ballot Google Elvire Beleoken Herve Leh Eleonora De Martin Catherine Johanet Didier Samuel Jean-Charles Duclos-Vallee Malcolm Buckle Eric Ballot Google Scholar Elvire Beleoken Herve Leh Eleonora De Martin Catherine Johanet Didier Samuel Jean-Charles Duclos-Vallee Malcolm Buckle Eric Ballot PubMed Elvire Beleoken Herve Leh Eleonora De Martin Catherine Johanet Didier Samuel Jean-Charles Duclos-Vallee Malcolm Buckle Eric Ballot Related Article in Frontiers Google Scholar PubMed Abstract Close Back to top Javascript is disabled. Please enable Javascript in your browser settings in order to see all the content on this page.

Abstract 4680: DNA dependent protein kinase as a new molecular target for treatment of non-small cell lung cancer

Abstract Prognosis with non-small cell lung cancer (NSCLC) has improved with the recent introduction of molecular targeted therapy. However, it is limited to patients with epidermal growth factor receptor (EGFR) mutations, who benefit from EGFR tyrosine kinase inhibitors (EGFR-TKI). A new molecular target is needed with other NSCLC patients. In general, chemotherapeutic agents cause DNA double-strand breaks (DNA DSB), leading to apoptosis of cancer cells; DNA repair reverses their effect, resulting in resistance to chemotherapy. DNA DSB repair can be mediated via two major pathways: homologous recombination (HR) and non-homologous end-joining (NHEJ). More than 90% of DSBs in mammalian cells are repaired by NHEJ, which is accomplished by core protein components including Ku70/Ku86, DNA-dependent protein kinase (DNA-PK), XRCC4, DNA ligase IV, Artemis, and Cernunnos-XLF. We recently reported that NK314, a dual inhibitor of topoisomerase IIα (Top2β) and DNA-PK, evidences a potent anti-tumor effect in adult T-cell leukemia-lymphoma (ATL). NK314 induced DNA DSBs and inhibited DNA repair mediated through degradation of the DNA-PK catalytic subunit (DNA-PKcs). In the present study, we examined the effect of NK314 in NSCLC cell lines and assessed DNA-PK as a possible molecular target for NSCLC. Twenty separate NSCLC cell lines were used, with IC50 varying from 46-193 nM. Levels of DNA-PKcs protein varied among the cell lines, whereas those of Ku70 and Ku86 did not. The inhibitory effect of cell growth was closely related to level of DNA-PKcs protein, but not to levels of other DNA-damage-activated protein kinases such as ATM or ATR. Establishment of predictive markers concomitantly with the development of a novel molecular target is indispensable for clinical application. Because detection of DNA-PKcs in peripheral blood is difficult, we investigated an alternative marker for predicting DNA-PKcs inhibitor. We previously found that heterogeneous nuclear ribonucleoprotein B1 (hnRNP B1), an RNA binding protein, interacts with DNA-PK, and we established a system for detecting hnRNP B1 mRNA in peripheral blood. We therefore examined the suitability of hnRNP B1 as an alternative biomarker for DNA-PK inhibitors. Close correlation between levels of DNA-PKcs and hnRNP B1 proteins was established using Western blot analysis with NSCLC cell lines (p=0.995). These results suggest that DNA-PK is a novel molecular target for NSCLC, and detection of hnRNP B1 might serve as an alternative molecular marker for the amount of DNA-PK inhibitors. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4680. doi:1538-7445.AM2012-4680

The perioperative change and clinical significance of the expression level of peripheral blood hnRNP B1 mRNA in NSCLC patients

Objective The aim of this study was to investigate the perioperative expression of the peripheral blood hnRNP B1 mRNA in non-small-cell lung cancer (NSCLC) patients and its clinical significance.

Expression proteomics of UPF1 knockdown in HeLa cells reveals autoregulation of hnRNP A2/B1 mediated by alternative splicing resulting in nonsense-mediated mRNA decay

BackgroundIn addition to acting as an RNA quality control pathway, nonsense-mediated mRNA decay (NMD) plays roles in regulating normal gene expression. In particular, the extent to which alternative splicing is coupled to NMD and the roles of NMD in regulating uORF containing transcripts have been a matter of debate. ResultsIn order to achieve a greater understanding of NMD regulated gene expression we used 2D-DiGE proteomics technology to examine the changes in protein expression induced in HeLa cells by UPF1 knockdown. QPCR based validation of the corresponding mRNAs, in response to both UPF1 knockdown and cycloheximide treatment, identified 17 bona fide NMD targets. Most of these were associated with bioinformatically predicted NMD activating features, predominantly upstream open reading frames (uORFs). Strikingly, however, the majority of transcripts up-regulated by UPF1 knockdown were either insensitive to, or even down-regulated by, cycloheximide treatment. Furthermore, the mRNA abundance of several down-regulated proteins failed to change upon UPF1 knockdown, indicating that UPF1's role in regulating mRNA and protein abundance is more complex than previously appreciated. Among the bona fide NMD targets, we identified a highly conserved AS-NMD event within the 3' UTR of the HNRNPA2B1 gene. Overexpression of GFP tagged hnRNP A2 resulted in a decrease in endogenous hnRNP A2 and B1 mRNA with a concurrent increase in the NMD sensitive isoforms.ConclusionsDespite the large number of changes in protein expression upon UPF1 knockdown, a relatively small fraction of them can be directly attributed to the action of NMD on the corresponding mRNA. From amongst these we have identified a conserved AS-NMD event within HNRNPA2B1 that appears to mediate autoregulation of HNRNPA2B1 expression levels.

Cell death induced by N-methyl-N-nitrosourea, a model SN1 methylating agent, in two lung cancer cell lines of human origin

New therapeutic approaches are needed for lung cancer, the leading cause of cancer death. Methylating agents constitute a widely used class of anticancer drugs, the effect of which on human non small cell lung cancer (NSCLC) has not been adequately studied. N-methyl-N-nitrosourea (MNU), a model S(N)1 methylating agent, induced cell death through a distinct mechanism in two human NSCLC cell lines studied, A549(p53(wt)) and H157(p53(null)). In A549(p53(wt)), MNU induced G2/M arrest, accompanied by cdc25A degradation, hnRNP B1 induction, hnRNP C1/C2 downregulation. Non-apoptotic cell death was confirmed by the lack of increase in the sub-G1 DNA content, Poly (ADP-ribose) polymerase cleavage and caspase-3, -7 activation. In H157(p53(null)), MNU induced apoptotic cell death, confirmed by cytofluorometry of DNA content and immunodetection of apoptotic markers, accompanied by overexpression of hnRNP B1 and C1/C2. Thus, the mechanism of the cell death induced by S(N)1 methylating agents is cell type-dependent and must be assessed prior treatment.

Comparison of Osteopontin, β-catenin and hnRNP B1 Expression in Lung Carcinomas

This study was performed to compare osteopontin (OPN), beta-catenin and heterogeneous nuclear ribonucleoprotein B1 (hnRNP B1) immunreactivities in small cell lung carcinomas (SCLC) and non-small cell lung carcinomas (NSCLC). Correlation of these three antibodies with grade and clinicopathologic stage of the tumor in NSCLC was also investigated. Twenty-nine SCLC, 6 large cell carcinoma, 36 adenocarcinoma and 30 squamous cell carcinoma (SCC), totally 101 cases, were included in this study. OPN, beta-catenin and hnRNP B1 expressions were immunohistochemically evaluated. OPN positivity was 6.9% in SCLC and 67% in NSCLC. When NSCLC types were individually considered, OPN positivity was 66.7% in large cell carcinoma, 80% in SCC and 55.6% in adenocarcinomas. beta-catenin positivity was observed in 48.6% of NSCLC and none of SCLC cases. These results were statistically significant (p < 0.05). Neither grade nor stage of NSCLC was correlated with osteopontin, beta-catenin or hnRNP B1 immunreactivity. We observed that OPN and beta-catenin are useful in differentiating SCLC from NSCLC. This may be helpful in small lung biopsies where morphology is obscured by crush artifacts.

Comparative Quantification of Plasma hnRNP B1 mRNA in Non-small Cell Lung Cancer Patients by Real-time PCR

Circulating cell-free nucleic acids are known to be a noninvasive diagnostic tool for cancer detection. Heterogeneous nuclear ribonucleoprotein (hnRNP) B1, a nuclear core complex, is overexpressed in early stage lung cancer. We intended to evaluate the usefulness of plasma hnRNP B1 mRNA in differentiating non-small cell lung cancer (NSCLC) from other benign lung diseases, especially pulmonary tuberculosis, which is highly prevalent in Korea and often difficult to distinguish from lung cancer. Plasma RNA was extracted from 30 patients with NSCLC, 30 patients with benign lung diseases including pulmonary tuberculosis, and 10 healthy controls. Plasma hnRNP B1 mRNA was measured by TaqMan Gene Expression Assay (Applied Biosystems, USA), and pre-developed beta-actin (ACTB) mRNA was used for normalization. We analyzed the relative gene expression data using the delta-delta Ct method. Plasma hnRPN B1 mRNA was measurable in 93.3% (28/30) of NSCLC patients. Normalized 2-DeltaDeltaCt of plasma hnRPN B1 mRNA was 62.2 (95%Cl, 6.4-210.1) in NSCLC patients and 2.7 (95%Cl, 0.5-13.6) in benign lung disease patients (P<0.001, Mann-Whitney U test). Plasma hnRNP B1 mRNA was significantly increased in patients with lung cancer compared with that in patients with other benign lung diseases. Plasma hnRNP B1 mRNA may be useful as a potential marker for the detection of NSCLC.

The Expression Inhibition of HnRNP B1 in Lung Cell Line A549 by Small Interfering RNA

Background: Preliminary studies indicate a relative link between the expression of heterogeneous nuclear ribonucleoproteins (hnRNPs) and cancer. Overexpression of hnRNP B1 correlated with the eventual development of lung cancer. Here we describe inhibition of HnRNP B1 replication in human lung cell line A549 by siRNAs targeted to various regions of hnRNP B1 sequences. Methods: Small interfering RNA technique was used to interfer the expression of hnRNPB1 in Lung Cell Line A549 in vitro; the RT-PCR and Western blot technique were used to detect the quantity of hnRNPB1 mRNA and its protein; flow cytometry was used to detect the apoptosis; then the cells were transfected to nude mice. Results: We demonstrated that plasmidderived siRNAs could inhibit hnRNP B1 mRNA and protein expression, and the siRNA expressed from activated plasmid in A549 cells could suppress the cell proliferation by increasing the G1 cells. Our experiment also found that siRNA could induce apoptosis. Conclusions: These results demonstrated the effectiveness of siRNA in lung cancer cells, which indicated a possible clinical therapy method for lung cancer development.

Establishment of a new method, transcription–reverse transcription concerted reaction, for detection of plasma hnRNP B1 mRNA, a biomarker of lung cancer

Development of an early detection marker is one of the most important strategies for improving overall prognosis in lung cancer patients. We previously reported that hnRNP B1--an RNA binding protein--is overexpressed in lung cancer tissue from the early stage of cancer, and found that hnRNP B1 mRNA is detectable in the plasma of lung cancer patients using real-time RT-PCR. The purpose of this study was to establish a quick and simple method for detecting plasma hnRNP B1mRNA for use in screening for lung cancer. TRC, a homogenous method for fluorescence real-time monitoring of isothermal RNA amplification using intercalation activating fluorescence DNA probe, was used to detect plasma hnRNP B1 mRNA. The detection limit of hnRNP B1 mRNA by TRC using synthetic control RNA or total RNA derived from a lung cancer cell line was 25 or 8.65 x 10(2) copies, respectively. Using total RNA extracted from 600 mul of plasma, we detected hnRNP B1 mRNA in 39.1% (9/23) of lung cancer patients, with levels ranging from 1.9 to 19,045.5 copies/100 ng RNA, and in 5.2% (5/97) of healthy volunteers. Copy numbers were not associated with age, gender, smoking status, or histological type of cancer. TRC could detect 10(3) copies of hnRNP B1 mRNA in 10 min. Detection of plasma hnRNP B1 mRNA by TRC is a quick, easy, and non-invasive method suitable for lung cancer screening.

Isolation of the protein B23/nucleophosmin from HeLa cell nuclei

Endogenous forms of the protein B23 were for the first time isolated from HeLa cell nuclei and their structural states were analyzed. It was demonstrated that incubation of HeLa cell nuclei in 10 mM Tris-HCl buffer (pH 7.4) led, not only to their swelling, but also to the release of several nuclear proteins, including the protein B23. PAGE of the supernatant fraction allowed nine major stained protein bands to be detected; the bands were identified by MALDI mass spectrometry (matrix-assisted laser desorption and ionization). The proteins in the range of 35-40 kDa were identified as nucleophosmin, glyceraldehyde 3-phosphate dehydrogenase (GAPDH), and heterogeneous nuclear ribonucleoprotein (hnRNP) A2/B1. Analysis of the N- and C-terminal amino acid sequences showed the presence of the isoforms B23.1 and B23.2, GAPDH, and the isoform hnRNP B1 and made it possible to describe the C- and N- terminal processing patterns and demonstrate the presence of isoform B23.2 at a protein level.

Great potential of a panel of multiple hMTH1, SPD, ITGA11 and COL11A1 markers for diagnosis of patients with non-small cell lung cancer

Research on molecular mechanisms underlying the carcinogenesis of non-small cell lung cancer (NSCLC) may provide gene targets in critical pathways valuable for improving the efficacy of therapy and survival of patients with NSCLC. However, the molecular markers highly sensitive for the prognosis and treatment evaluation of NSCLC are not yet available. To explore candidates, we conducted an oligonucleotide microarray study with three pairs of NSCLC and normal lung tissue, and determined 8 differentially expressed genes including the Human MutT homologue (hMTH1), Surfactant protein D (SPD), Human hyaluronan binding protein 2 (HABP2), Crystalline-mu (CRYM), Ceruloplasmin (CP), Integrin alpha-11 subunit (ITGA11), Collagen type XI alpha I (COL11A1), and Lung-specific X protein (Lun X). Four lung cancer-related markers MUC-1, hTERT, hnRNP B1, and CK-19 were also incorporated for further analysis. The expression profiles of the twelve genes in seventy pairs of NSCLC tumor and normal lung tissue were then detected quantitatively by using membrane array and quantitative real-time PCR (qRT-PCR). The data of the membrane array and qRT-PCR were compared for consistency and the potential of these mRNA markers in clinical application. The results showed that membrane array and qRT-PCR obtained consistent data for the tested genes in both sensitivity and specificity (correlation coefficient 0.921, p<0.0001). For patients' clinicopathological characteristics, the overexpression of hMTH1, SPD, HABP 2, ITGA11, COL11A1, and CK-19 was significantly correlated with the pathological stage (p<0.05). In addition, the overexpression of hMTH1, SPD, ITGA11, and COL11A1 was correlated with lymph node metastasis and poor prognosis. This is the first report relating SPD to a prognosis marker for NSCLC. Moreover, the combined detection of these four mRNA markers by membrane array had a sensitivity of 89% and a specificity of 84% for NSCLC, significantly higher than these markers had achieved separately. In conclusion, we identified mRNA markers for NSCLC prognosis and therapy evaluation from differentially expressed genes determined by using micro-array. Further studies are needed to collect the data of the mRNA markers used in clinical practice.