YB-1 relocates to the nucleus in adenovirus-infected cells and facilitates viral replication by inducing E2 gene expression through the E2 late promoter

Development of an optimized, non-stem cell line for intranasal delivery of therapeutic cargo to the central nervous system

Neural stem cells (NSCs) are considered to be valuable candidates for delivering a variety of anti-cancer agents, including oncolytic viruses, to brain tumors. However, owing to the previously reported tumorigenic potential of NSC cell lines after intranasal administration (INA), here we identified the human hepatic stellate cell line LX-2 as a cell type capable of longer resistance to replication of oncolytic adenoviruses (OAVs) as a therapeutic cargo, and that is non-tumorigenic after INA. Our data show that LX-2 cells can longer withstand the OAV XVir-N-31 replication and oncolysis than NSCs. By selecting the highly migratory cell population out of LX-2, an offspring cell line with a higher and more stable capability to migrate was generated. Additionally, as a safety backup, we applied genomic herpes simplex virus thymidine kinase (HSV-TK) integration into LX-2, leading to high vulnerability to ganciclovir (GCV). Histopathological analyses confirmed the absence of neoplasia in the respiratory tracts and brains of immuno-compromised mice 3 months after INA of LX-2 cells. Our data suggest that LX-2 is a novel, robust, and safe cell line for delivering anti-cancer and other therapeutic agents to the brain.

The adenovirus DNA-binding protein DBP

Adenoviruses are a group of double-stranded DNA viruses that can mainly cause respiratory, gastrointestinal, and eye infections in humans. In addition, adenoviruses are employed as vector vaccines for combatting viral infections, including SARS-CoV-2, and serve as excellent gene therapy vectors. These viruses have the ability to modulate the host cell machinery to their advantage and trigger significant restructuring of the nuclei of infected cells through the activity of viral proteins. One of those, the adenovirus DNA-binding protein (DBP), is a multifunctional non-structural protein that is integral to the reorganization processes. DBP is encoded in the E2A transcriptional unit and is highly abundant in infected cells. Its activity is unequivocally linked to the formation, structure, and integrity of virus-induced replication compartments, molecular hubs for the regulation of viral processes, and control of the infected cell. DBP also plays key roles in viral DNA replication, transcription, viral gene expression, and even host range specificity. Notably, post-translational modifications of DBP, such as SUMOylation and extensive phosphorylation, regulate its biological functions. DBP was first investigated in the 1970s, pioneering research on viral DNA-binding proteins. In this literature review, we provide an overview of DBP and specifically summarize key findings related to its complex structure, diverse functions, and significant role in the context of viral replication. Finally, we address novel insights and perspectives for future research.

YB-1-based oncolytic virotherapy in combination with CD47 blockade enhances phagocytosis of pediatric sarcoma cells

Oncolytic viruses (OVs) selectively replicate in tumor cells resulting in lysis, spreading of new infectious units and induction of antitumor immune responses through abrogating an immunosuppressive tumor microenvironment (TME). Due to their mode of action, OVs are ideal combination partners with targeted immunotherapies. One highly attractive combination is the inhibition of the 'don't-eat-me'-signal CD47, which is known to increase the phagocytic potential of tumor-associated macrophages. In this work, we analyzed the combination approach consisting of the YB-1-based oncolytic adenovirus XVir-N-31 (XVir) and the CD47 inhibitor (CD47i) B6.H12.2 concerning its phagocytic potential. We investigate phagocytosis of XVir-, adenovirus wildtype (AdWT)-, and non-infected established pediatric sarcoma cell lines by different monocytic cells. Phagocytes (immature dendritic cells and macrophages) were derived from THP-1 cells and healthy human donors. Phagocytosis of tumor cells was assessed via FACS analysis in the presence and absence of CD47i. Additional characterization of T cell-stimulatory surface receptors as well as chemo-/cytokine analyses were performed. Furthermore, tumor cells were infected and studied for the surface expression of the 'eat-me'-signal calreticulin (CALR) and the 'don't-eat-me'-signal CD47. We herein demonstrate that (1) XVir-infected tumor cells upregulate both CALR and CD47. XVir induces higher upregulation of CD47 than AdWT. (2) XVir-infection enhances phagocytosis in general and (3) the combination of XVir and CD47i compared to controls showed by far superior enhancement of phagocytosis, tumor cell killing and innate immune activation. In conclusion, the combination of CD47i and XVir causes a significant increase in phagocytosis exceeding the monotherapies considerably accompanied by upregulation of T cell-stimulatory receptor expression and inflammatory chemo/-cytokine secretion.

Y-Box Binding Protein 1: Unraveling the Multifaceted Role in Cancer Development and Therapeutic Potential

Y-box binding protein 1 (YBX1), a member of the Cold Shock Domain protein family, is overexpressed in various human cancers and is recognized as an oncogenic gene associated with poor prognosis. YBX1's functional diversity arises from its capacity to interact with a broad range of DNA and RNA molecules, implicating its involvement in diverse cellular processes. Independent investigations have unveiled specific facets of YBX1's contribution to cancer development. This comprehensive review elucidates YBX1's multifaceted role in cancer across cancer hallmarks, both in cancer cell itself and the tumor microenvironment. Based on this, we proposed YBX1 as a potential target for cancer treatment. Notably, ongoing clinical trials addressing YBX1 as a target in breast cancer and lung cancer have showcased its promise for cancer therapy. The ramp up in in vitro research on targeting YBX1 compounds also underscores its growing appeal. Moreover, the emerging role of YBX1 as a neural input is also proposed where the high level of YBX1 was strongly associated with nerve cancer and neurodegenerative diseases. This review also summarized the up-to-date advanced research on the involvement of YBX1 in pancreatic cancer.

Targeting Cell Cycle Facilitates E1A-Independent Adenoviral Replication

DNA replication of E1-deleted first-generation adenoviruses (AdV) in cultured cancer cells has been reported repeatedly and it was suggested that certain cellular proteins could functionally compensate for E1A, leading to the expression of the early region 2 (E2)-encoded proteins and subsequently virus replication. Referring to this, the observation was named E1A-like activity. In this study, we investigated different cell cycle inhibitors with respect to their ability to increase viral DNA replication of dl70-3, an E1-deleted adenovirus. Our analyses of this issue revealed that in particular inhibition of cyclin-dependent kinases 4/6 (CDK4/6i) increased E1-independent adenovirus E2-expression and viral DNA replication. Detailed analysis of the E2-expression in dl70-3 infected cells by RT-qPCR showed that the increase in E2-expression originated from the E2-early promoter. Mutations of the two E2F-binding sites in the E2-early promoter (pE2early-LucM) caused a significant reduction in E2-early promoter activity in trans-activation assays. Accordingly, mutations of the E2F-binding sites in the E2-early promoter in a virus named dl70-3/E2Fm completely abolished CDK4/6i induced viral DNA replication. Thus, our data show that E2F-binding sites in the E2-early promoter are crucial for E1A independent adenoviral DNA replication of E1-deleted vectors in cancer cells. IMPORTANCE E1-deleted AdV vectors are considered replication deficient and are important tools for the study of virus biology, gene therapy, and large-scale vaccine development. However, deletion of the E1 genes does not completely abolish viral DNA replication in cancer cells. Here, we report, that the two E2F-binding sites in the adenoviral E2-early promoter contribute substantially to the so-called E1A-like activity in tumor cells. With this finding, on the one hand, the safety profile of viral vaccine vectors can be increased and, on the other hand, the oncolytic property for cancer therapy might be improved through targeted manipulation of the host cell.

Targeting the Retinoblastoma/E2F repressive complex by CDK4/6 inhibitors amplifies oncolytic potency of an oncolytic adenovirus

CDK4/6 inhibitors (CDK4/6i) and oncolytic viruses are promising therapeutic agents for the treatment of various cancers. As single agents, CDK4/6 inhibitors that are approved for the treatment of breast cancer in combination with endocrine therapy cause G1 cell cycle arrest, whereas adenoviruses induce progression into S-phase in infected cells as an integral part of the their life cycle. Both CDK4/6 inhibitors and adenovirus replication target the Retinoblastoma protein albeit for different purposes. Here we show that in combination CDK4/6 inhibitors potentiate the anti-tumor effect of the oncolytic adenovirus XVir-N-31 in bladder cancer and murine Ewing sarcoma xenograft models. This increase in oncolytic potency correlates with an increase in virus-producing cancer cells, enhanced viral genome replication, particle formation and consequently cancer cell killing. The molecular mechanism that regulates this response is fundamentally based on the reduction of Retinoblastoma protein expression levels by CDK4/6 inhibitors.

Neither CDK4/6 inhibitors nor oncolytic adenoviruses show high efficiency as monotherapy in the treatment of cancer. Authors show here that when combined, CDK4/6 inhibitors deplete Retinoblastoma protein levels, which leads to more efficient virus replication and an increase in oncolytic virus-producing cancer cells and thus to efficient anti-tumor response in mouse xenograft sarcoma models.

A Single Amino Acid Switch in the Adenoviral DNA Binding Protein Abrogates Replication Center Formation and Productive Viral Infection

Adenoviruses are very efficient high-capacity vaccine vectors and are common gene delivery systems. Despite their extensive use in preclinical models and clinical trials over the past decades, adenoviral vectors still require optimization. To achieve that, more thorough characterizations of adenoviral genes and gene products, as well as pathogen-host interactions, are indispensable. The adenoviral DNA binding protein (DBP) is a key regulatory protein involved in various cellular and viral processes. Here, we show that single amino acid exchange mutations in human adenovirus C5 (HAdV-C5) DBP strongly influence adenoviral replication by altering interaction with the cellular ubiquitination machinery. Specifically, phenotypic analyses of DBP mutants demonstrate that single amino acid substitutions can regulate interactions with the cellular USP7 deubiquitinase, impede viral DNA synthesis, and completely abolish viral late protein expression and progeny production. Importantly, cells infected with the DBP mutant UBM5 consistently lack DBP-positive replication centers (RCs), which are usually formed during the transition from the early to the late phase of infection. Our findings demonstrate that DBP regulates a key step at the onset of the late phase of infection and that this activity is unambiguously linked to the formation and integrity of viral RCs. These data provide the experimental basis for future work that targets DBP and its interference with the formation of viral RCs during productive infection. Consequently, this work will have immediate impact on DNA virus and adenovirus research in general and, potentially, also on safety optimization of existing and development of novel adenoviral vectors and anti-adenoviral compounds.

E1B-55K is a phosphorylation-dependent transcriptional and post-transcriptional regulator of viral gene expression in HAdV-C5 infection

The multifunctional adenoviral E1B-55K phosphoprotein is a major regulator of viral replication and plays key roles in virus-mediated cell transformation. While much is known about its function in oncogenic cell transformation, underlying features and exact mechanisms that implicate E1B-55K in regulation of viral gene expression are less well understood. Therefore, this work aimed at unravelling basic intranuclear principles of E1B-55K-regulated viral mRNA biogenesis using wild type HAdV-C5 E1B-55K, a virus mutant with abrogated E1B-55K expression and a mutant that expresses a phosphomimetic E1B-55K. By subnuclear fractionation, mRNA, DNA and protein analyses as well as luciferase reporter assays, we show that (i) E1B-55K promotes efficient release of viral late mRNAs from their site of synthesis in viral replication compartments (RCs) to the surrounding nucleoplasm, that (ii) E1B-55K modulates the rate of viral gene transcription and splicing in RCs, that (iii) E1B-55K participates in the temporal regulation of viral gene expression, that (iv) E1B-55K can enhance or repress the expression of viral early and late promoters and that (v) the phosphorylation of E1B-55K regulates the temporal effect of the protein on each of these activities. Together, these data demonstrate that E1B-55K is a phosphorylation-dependent transcriptional and post-transcriptional regulator of viral genes during HAdV-C5 infection. Importance Human adenoviruses are useful models to study basic aspects of gene expression and splicing. Moreover, they are one of the most commonly used viral vectors for clinical applications. However, key aspects of the activities of essential viral proteins that are commonly modified in adenoviral vectors have not been fully described. A prominent example is the multifunctional adenoviral oncoprotein E1B-55K that is known to promote efficient viral genome replication and expression while simultaneously repressing host gene expression and antiviral host responses. Our study combined different quantitative methods to study how E1B-55K promotes viral mRNA biogenesis. The data presented here propose a novel role for E1B-55K as a phosphorylation-dependent transcriptional and post-transcriptional regulator of viral genes.

Diverse Regulation of YB-1 and YB-3 Abundance in Mammals

YB proteins are DNA/RNA binding proteins, members of the family of proteins with cold shock domain. Role of YB proteins in the life of cells, tissues, and whole organisms is extremely important. They are involved in transcription regulation, pre-mRNA splicing, mRNA translation and stability, mRNA packaging into mRNPs, including stress granules, DNA repair, and many other cellular events. Many processes, from embryonic development to aging, depend on when and how much of these proteins have been synthesized. Here we discuss regulation of the levels of YB-1 and, in part, of its homologs in the cell. Because the amount of YB-1 is immediately associated with its functioning, understanding the mechanisms of regulation of the protein amount invariably reveals the events where YB-1 is involved. Control over the YB-1 abundance may allow using this gene/protein as a therapeutic target in cancers, where an increased expression of the YBX1 gene often correlates with the disease severity and poor prognosis.

Y-box Binding Protein 1: Looking Back to the Future

Y-box binding protein 1 is a member of the cold shock domain (CSD) protein family and one of the most studied proteins associated with a large number of human diseases. This review aims to critically reassess the growing number of pathological functions ascribed to YB-1 in the past decades. The focus is given on the important role of YB-1 and related CSD proteins in the physiology of normal cells. The functional significance of these proteins is highlighted by their high evolutionary conservation from bacteria to men, where they are ubiquitously expressed and involved in coordinating all steps of mRNA biogenesis, including transcription, translation, storage, and degradation. Their activities are especially important under conditions requiring rapid change in the gene expression programs, such as early embryonic development, differentiation, stress, and adaptation to new environments. Therefore, to define a precise role of YB-1 in tumorigenic transformation and in other pathological conditions, it is important to understand its basic properties and functions in normal cells, and how they are interrupted in complex diseases including cancer.

Concepts in Oncolytic Adenovirus Therapy

Oncolytic adenovirus therapy is gaining importance as a novel treatment option for the management of various cancers. Different concepts of modification within the adenovirus vector have been identified that define the mode of action against and the interaction with the tumour. Adenoviral vectors allow for genetic manipulations that restrict tumour specificity and also the expression of specific transgenes in order to support the anti-tumour effect. Additionally, replication of the virus and reinfection of neighbouring tumour cells amplify the therapeutic effect. Another important aspect in oncolytic adenovirus therapy is the virus induced cell death which is a process that activates the immune system against the tumour. This review describes which elements in adenovirus vectors have been identified for modification not only to utilize oncolytic adenovirus vectors into conditionally replicating adenoviruses (CRAds) that allow replication specifically in tumour cells but also to confer specific characteristics to these viruses. These advances in development resulted in clinical trials that are summarized based on the conceptual design.

Trimethylamine N-oxide mediated Y-box binding protein-1 nuclear translocation promotes cell cycle progression by directly downregulating Gadd45a expression in a cellular model of chronic kidney disease

AIMS

Cell cycle arrest plays critical roles in preventing renal tubular epithelial cell (RTEC) injury and maladaptation after the onset of chronic kidney disease (CKD), but the underlying mechanism governing this arrest has not been fully elucidated. This study was designed to determine the underlying role of YB-1 in promoting cell cycle progression and nuclear translocation in HK-2 cells induced by trimethylamine N-oxide (TMAO).

MAIN METHODS

YB-1 primarily accumulated in the cytoplasm in HK-2 cells after they were treated with TMAO for 30 min and 6 h. Gene expression was analysed using RNA sequencing in HK-2 cells treated with TMAO. Cell cycle progression was analysed via flow cytometry. Luciferase assay and ChIP-PCR were performed to determine the relationship between transcription factor YB-1 and Gadd45a promoter region. Additionally, mice were fed with TMAO to test renal dysfunction and measure the expression of YB-1, GADD45a and CCNA2 in the kidney sections through immunohistochemistry.

KEY FINDINGS

YB-1 primarily accumulated in the cytoplasm in HK-2 cells after they were treated with TMAO for 30 min and 6 h. RNA sequencing analysis showed that the cell cycle checkpoint genes growth arrest and DNA damage (Gadd)45a, Gadd45g, cyclin (Ccn)a2, Ccnb1, Ccne1 and Ccnf were differentially expressed in HK-2 cells after treated with 400 μM TMAO for 30 min. Flow cytometry results demonstrated that cell cycle progression was blocked at the G2/M checkpoint. In animal models, elevated dietary TMAO directly led to progressive renal tubulointerstitial dysfunction and inhibited the expression of YB-1 in kidney. Moreover, YB-1 was determined to regulate Gadd45a expression by directly binding to its promoter region. YB-1 expression was negatively correlated with the expression of Gadd45a and Gadd45g but positively correlated with Ccna2, Ccnb1, Ccne1 and Ccnf in CKD.

SIGNIFICANCE

YB-1 may be a reliable molecular target and an effective prognostic biomarker for CKD.

Potential Links between YB-1 and Fatty Acid Synthesis in Clear Cell Renal Carcinoma

According to the National Institutes of Health, clear cell renal cell carcinoma (ccRCC) is the most common type of Renal Cell Carcinoma (RCC), making up approximately 75% of total renal carcinoma cases. Clear cell Renal Cell Carcinoma is characterized by a significant accumulation of lipids in the cytoplasm, which allows light from microscopes to pass through giving them a "clear" phenotype. Many of these lipids are in the form of fatty acids, both free and incorporated into lipid droplets. RCC is typically associated with a poor prognosis due to the lack of specific symptoms. Some symptoms include blood in urine, fever, lump on the side, weight loss, fatigue, to name a few; all of which can be associated with non-specific, non-cancerous, health conditions that contribute to difficult diagnosis. Treatment of RCC has typically been centered around radical nephrectomy as the standard of care, but due to the potentially small size of lesions and the possibility of causing surgically induced chronic kidney disease, treatments have shifted to more cautious, less invasive approaches. These approaches include active surveillance, nephron-sparing surgery, and other minimally invasive techniques like cryotherapy and renal ablation. Although these techniques have had the desired effect of reducing the number of surgeries, there is still considerable potential for renal impairment and the chance that tumors can grow out of control without surgery. With the difficulty that surrounds the treatment of ccRCC and its considerably high mortality rate amongst urological cancers, it is important to look for novel approaches to improve patient outcomes. This review looks at available literature and our data that suggests the lipogenic enzyme stearoyl-CoA desaturase may be more beneficial to patient survival than once thought. As our understanding of the importance of lipids in cell metabolism and longevity matures, it is important to present new perspectives that present a new understanding of ccRCC and the role of lipids in survival mechanisms engaged by transformed cells during cancer progression. In this review, we provide evidence that pharmacological inhibition of lipid desaturation in renal cancer patients is not without risk, and that the presence of unsaturated fatty acids may be a beneficial factor in patient outcomes. Although more direct experimental evidence is needed to make definitive conclusions, it is clear that the work reviewed herein should challenge our current understanding of cancer biology and may inform novel approaches to the diagnosis and treatment of ccRCC.

YB-1 Mediates TNF-Induced Pro-Survival Signaling by Regulating NF-κB Activation

Cell fate decisions regulating survival and death are essential for maintaining tissue homeostasis; dysregulation thereof can lead to tumor development. In some cases, survival and death are triggered by the same receptor, e.g., tumor necrosis factor (TNF)-receptor 1 (TNFR1). We identified a prominent role for the cold shock Y-box binding protein-1 (YB-1) in the TNF-induced activation and nuclear translocation of nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) p65. In the absence of YB-1, the expression of TNF receptor-associated factor 2 (TRAF2), a central component of the TNF receptor signaling complex required for NF-κB activation, is significantly reduced. Therefore, we hypothesized that the loss of YB-1 results in a destabilization of TRAF2. Consistent with this hypothesis, we observed that YB-1-deficient cells were more prone to TNF-induced apoptotic cell death. We observed enhanced effector caspase-3 activation and could successfully rescue the cells using the pan-caspase inhibitor zVAD-fmk, but not necrostatin-1. Taken together, our results indicate that YB-1 plays a central role in promoting cell survival through NF-κB activation and identifies a novel mechanism by which enhanced YB-1 expression may contribute to tumor development.

Y-Box Binding Proteins in mRNP Assembly, Translation, and Stability Control

Y-box binding proteins (YB proteins) are DNA/RNA-binding proteins belonging to a large family of proteins with the cold shock domain. Functionally, these proteins are known to be the most diverse, although the literature hardly offers any molecular mechanisms governing their activities in the cell, tissue, or the whole organism. This review describes the involvement of YB proteins in RNA-dependent processes, such as mRNA packaging into mRNPs, mRNA translation, and mRNA stabilization. In addition, recent data on the structural peculiarities of YB proteins underlying their interactions with nucleic acids are discussed.

Calcium Influx Caused by ER Stress Inducers Enhances Oncolytic Adenovirus Enadenotucirev Replication and Killing through PKCα Activation

Oncolytic viruses represent an emerging approach to cancer therapy. However, better understanding of their interaction with the host cancer cell and approaches to enhance their efficacy are needed. Here, we investigate the effect of chemically induced endoplasmic reticulum (ER) stress on the activity of the chimeric group B adenovirus Enadenotucirev, its closely related parental virus Ad11p, and the archetypal group C oncolytic adenovirus Ad5. We show that treatment of colorectal and ovarian cancer cell lines with thapsigargin or ionomycin caused an influx of Ca2+, leading to an upregulation in E1A transcript and protein levels. Increased E1A protein levels, in turn, increased levels of expression of the E2B viral DNA polymerase, genome replication, late viral protein expression, infectious virus particle production, and cell killing during Enadenotucirev and Ad11p, but not Ad5, infection. This effect was not due to the induction of ER stress, but rather the influx of extracellular Ca2+ and consequent increase in protein kinase C activity. These results underscore the importance of Ca2+ homeostasis during adenoviral infection, indicate a signaling pathway between protein kinase C and E1A, and raise the possibility of using Ca2+ flux-modulating agents in the manufacture and potentiation of oncolytic virotherapies.

The biology of the adenovirus E1B 55K protein

The adenovirus E1B 55K (E1B) protein plays major roles in productive adenoviral infection and cellular transformation. Interest in E1B increased because of the potential of adenoviruses as therapeutic vectors, and the E1B gene is commonly deleted from adenovirus vectors for anticancer therapy. E1B activities are spatiotemporally regulated through SUMOylation and phosphorylation, and through interactions with multiple partners that occur presumably at different intracellular sites and times postinfection. E1B is implicated in the formation of viral replication compartments and regulates viral genome replication and transcription, transcriptional repression, degradation of cellular proteins, and several intranuclear steps of viral late mRNA biogenesis. Here, we review advances in our understanding of E1B during productive adenovirus replication and discuss fundamental aspects that remain unresolved.

Formation of adenovirus DNA replication compartments

Adenoviruses induce an extensive reorganization of the host cell nucleus during replication. Such a process results in the assembly of viral and cellular macromolecules into nuclear structures called adenovirus replication compartments (AdRCs), which function as platforms for viral DNA replication and gene expression. AdRCs co-opt host proteins and cellular pathways that restrict viral replication, suggesting that the mechanisms that control AdRC formation and function are essential for viral replication and lay at the basis of virus-host interactions. Here, we review the hallmarks of AdRCs and recent progress in our understanding of the formation, composition, and function of AdRCs. Furthermore, we discuss how AdRCs facilitate the interplay between viral and cellular machineries and hijack cellular functions to promote viral genome replication and expression.

Effects of Y Box Binding Protein-1 in Progression and Prognosis of Cholangiocarcinoma

Background and Objective: The preferred treatment for Cholangiocarcinoma (CCA) patients is surgery. Approximately, 35% of patients can undergo surgical resection in clinic. Biomarkers for CCA need to be identified for diagnosis, treatment, or prognosis prediction of this disease. Y-box binding protein-1 (YBOX-1) is highly correlated with tumor progression and poor overall survival in many malignancies. The prognostic value of YBOX-1 overexpression in CCA remains unclear. We examined the expression of YBOX-1 in resected tissue in CCA patients and studied the effect of YBOX-1 in CCA migration and invasion in vitro and in vivo. Methods: Expression of YBOX-1 in the tissue of 91 CCA patients was investigated by immunohistochemistry. The effects of YBOX-1 on migration, invasion, and proliferation in CCA cell lines were assessed by short hairpin RNA lentivirus or overexpression plasmid transfection. Results: A total of 55 (60.4%) of CCA cancerous tissues showed strongly positive YBOX-1 cytoplasmic staining. The strongly positive expression of YBOX-1 was close to early recurrence and poor overall survival by Kaplan-Meier analyses. Knockdown of YBOX-1 reduced migration and invasion in CCA cells and proliferation of tumor in xenotransplantation nude mice. Overexpression of YBOX-1 promoted migration and invasion in CCA cells and proliferation of tumor in xenotransplantation nude mice. Conclusion: YBOX-1 is correlated with early recurrence and poor overall survival in CCA. YBOX-1 may be a factor of predicting poor prognosis and overall survival.

Irradiation enhances the therapeutic effect of the oncolytic adenovirus XVir-N-31 in brain tumor initiating cells

Virotherapy using oncolytic viruses is an upcoming therapy strategy for cancer treatment. A variety of preclinical and clinical trials have indicated that adenoviruses may be used as potent agents in the treatment of a variety of cancers, and also for the treatment of brain tumors. In these studies, it has also been shown that oncovirotherapy is safe in terms of toxicity and side effects. In addition, previous studies have presented evidence for a significant role of oncovirotherapy in the activation of anti‑tumor immune responses. With regard to oncolytic adenoviruses, we have demonstrated previously that the multifunctional protein Y‑box binding protein‑1 (YB‑1) is a potent factor that was used to develop an YB‑1‑dependent oncolytic adenovirus (XVir‑N‑31). XVir‑N‑31 provides the opportunity for tumor‑selective replication and exhibited marked oncolytic properties in a mouse glioma tumor model using therapy‑resistant brain tumor initiating cells (BTICs). In a number of, but not all, patients with glioma, YB‑1 is primarily located in the nucleus; this promotes XVir‑N‑31‑replication and subsequently tumor cell lysis. However, in certain BTICs, only a small amount of YB‑1 has been identified to be nuclear, and therefore virus replication is suboptimal. YB‑1 in BTICs was demonstrated to be translocated into the nucleus following irradiation, which was accompanied by an enhancement in XVir‑N‑31 production. R28 glioma spheres implanted in living organotypic human brain slices exhibited a significantly delayed growth rate when pre‑irradiated prior to XVir‑N‑31‑infection as compared with single treatment methods. Consistent with the in vitro data, R28 glioma‑bearing mice exhibited a prolonged mean and median survival following single tumor irradiation prior to intratumoral XVir‑N‑31 injection, compared with the single treatment methods. In conclusion, the present study demonstrated that in an experimental glioma model, tumor irradiation strengthened the effect of an XVir‑N‑31‑based oncovirotherapy.

Investigation of function and regulation of the YB-1 cellular factor in HIV replication

Y-box binding protein 1 (YB-1) is a member of the cold-shock domain (CSD) protein superfamily. It participates in a wide variety of cellular events, including transcription, RNA splicing, translation, DNA repair, drug resistance, and stress responses. We investigated putative functions of YB-1 in HIV-1 replication. Functional studies using overexpression or knockdown of YB-1 in conjunction with transfection of proviral DNA showed that YB-1 enhances virus production. We found YB-1 regulates HIV-1 production by stimulating viral transcription using HIV-1 LTR sequence U3RU5 with Luciferase assay. We also identified a specific region from amino acids 1 to 324 of YB-1 as necessary for the participation of the protein in the production of virions.

Maternal Ybx1 safeguards zebrafish oocyte maturation and maternal-to-zygotic transition by repressing global translation

Maternal mRNAs and proteins dictate early embryonic development before zygotic genome activation. In the absence of transcription, elaborate control of maternal mRNA translation is of particular importance for oocyte maturation and early embryogenesis. By analyzing zebrafish ybx1 mutants with a null allele, we demonstrate an essential role of maternal ybx1 in repressing global translation in oocytes and embryos. Loss of maternal Ybx1 leads to impaired oocyte maturation and egg activation. Maternal ybx1 (Mybx1) mutant embryos fail to undergo normal cleavage and the maternal-to-zygotic transition (MZT). Morpholino knockdown of ybx1 also results in MZT loss and epiboly failure, suggesting the postfertilization requirement of Ybx1. In addition, elevated global translation level and the unfolded protein response were found in Ybx1-depleted embryos. Supplementing translational repression by eIF4E inhibition markedly rescues the Mybx1 phenotype. Mechanistically, Ybx1 in embryos may associate with processing body components and repress translation when tethered to target mRNAs. Collectively, our results identify maternal Ybx1 as a global translational repressor required for oocyte maturation and early embryogenesis.

The Oncolytic Adenovirus XVir-N-31 as a Novel Therapy in Muscle-Invasive Bladder Cancer

Muscle-invasive bladder cancer represents approximately 25% of diagnosed bladder cancer cases and carries a significant risk of death. Oncolytic viruses are novel antitumor agents with the ability to selectively replicate and lyse tumor cells while sparing healthy tissue. We explored the efficiency of the oncolytic YB-1-selective adenovirus XVir-N-31 in vitro and in an orthotopic mouse model for bladder cancer by intramural injection under ultrasound guidance. We demonstrated that XVir-N-31 replicated in bladder cancer cells and induced a stronger immunogenic cell death than wild-type adenovirus by facilitating enhanced release of HMGB1 and exosomal Hsp70. The intratumoral delivery of XVir-N-31 by ultrasound guidance delayed tumor growth in an immunodeficient model, demonstrating the feasibility of this approach to deliver oncolytic viruses directly into the tumor.

Y-box-binding protein 1 supports the early and late steps of HIV replication

The human immunodeficiency virus (HIV) depends on cellular proteins, so-called cofactors, to complete its replication cycle. In search for new therapeutic targets we identified the DNA and RNA binding protein Y-box-binding Protein 1 (YB-1) as a cofactor supporting early and late steps of HIV replication. YB-1 depletion resulted in a 10-fold decrease in HIV-1 replication in different cell lines. Dissection of the replication defects revealed that knockdown of YB-1 is associated with a 2- to 5-fold decrease in virion production due to interference with the viral RNA metabolism. Using single-round virus infection experiments we demonstrated that early HIV-1 replication also depends on the cellular YB-1 levels. More precisely, using quantitative PCR and an in vivo nuclear import assay with fluorescently labeled viral particles, we showed that YB-1 knockdown leads to a block between reverse transcription and nuclear import of HIV-1. Interaction studies revealed that YB-1 associates with integrase, although a direct interaction with HIV integrase could not be unambiguously proven. In conclusion, our results indicate that YB-1 affects multiple stages of HIV replication. Future research on the interaction between YB-1 and the virus will reveal whether this protein qualifies as a new antiviral target.

Expression and network analysis of YBX1 interactors for identification of new drug targets in lung adenocarcinoma

Y-Box Binding protein 1 (YBX-1) is known to be involved in various types of cancers. It's interactors also play major role in various cellular functions. Present work aimed to study the expression profile of the YBX-1 interactors during lung adenocarcinoma (LUAD). The differential expression analysis involved 57 genes from 95 lung adenocarcinoma samples, construction of gene network and topology analysis. A Total of 43 genes were found to be differentially expressed from which 17 genes were found to be down regulated and 26 genes were up-regulated. We observed that Polyadenylate-binding protein 1 (PABPC1), a protein involved in YBX1 translation, is highly correlated with YBX1. The interaction network analysis for a differentially expressed non-coding RNA Growth Arrest Specific 5 (GAS5) suggests that two proteins namely, Growth Arrest Specific 2 (GAS2) and Peripheral myelin protein 22 (PMP22) are potentially involved in LUAD progression. The network analysis and differential expression suggests that Collagen type 1 alpha 2 (COL1A2) can be potential biomarker and target for LUAD.

Role of Y Box Protein-1 in cancer: As potential biomarker and novel therapeutic target

The Y-box binding protein (YB-1) is known to be a multifunctional transcription and translation factor during expression of several proteins. It is a vital oncoprotein that regulates cancer cell progression and proliferation. YB-1 is over-expressed in various human cancers such as breast cancer, colon cancer, lung cancer, gastric cancer, oesophageal cancer and glioblastoma. Nuclear expression of YB-1 is found to be associated with multidrug resistance and cancer cell progression. YB-1 is reported to regulate many cellular signalling pathways in different types of cancer proliferation. Knowledge about nuclear localization and nuclear level expression of YB-1 in different cancers has been correlated with prospective prognosis of cancer. This review discusses the prospects of YB-1 as a potential biomarker as well as therapeutic target in lieu of their role during cancer progression and multidrug resistance.

Nuclear expression of Y box binding-1 is important for resistance to chemotherapy including gemcitabine in TP53-mutated bladder cancer

The development and acquisition of multiple drug resistance in cancer cells remain a major obstacle in the treatment of bladder cancer. Nuclear translocation of Y box binding-1 (YB-1), which is a member of a family of DNA-binding proteins that contain a cold shock domain, plays a significant role in the acquisition of drug resistance by upregulating expression of the multidrug resistance-1 (MDR-1) gene product, p-glycoprotein. The tumor suppressor protein p53 is thought to be essential for nuclear translocation of YB-1. We hypothesized that nuclear translocation of YB-1 might be associated with drug resistance of bladder cancer with an abnormality of the TP53 gene that results in a mutated p53 protein. To test this hypothesis, we analyzed the association of YB-1 with drug resistance of TP53-mutated bladder cancer, including immunohistochemical analysis of YB-1, p-glycoprotein and p53 in vivo as well as the function of YB-1 nuclear translocation and regulation of its translocation by p53 in vitro. Additionally, we examined the association between the nuclear translocation of YB-1 and gemcitabine, a major anticancer-drug for bladder cancer, in cancer cell lines. Nuclear expression of YB-1 was correlated with the expression of p-glycoprotein and p53 in bladder cancer cases (p<0.05). In vitro, both introduction of TP53 and gemcitabine induced nuclear translocation of YB-1. These data indicate that YB-1 translocates to the nucleus coordinately with p53 expression and is involved in gemcitabine resistance in bladder cancer. Nuclear expression of YB-1 is important for resistance to chemotherapy including gemcitabine in TP53-mutated bladder cancer.

Etoposide enhances antitumor efficacy of MDR1-driven oncolytic adenovirus through autoupregulation of the MDR1 promoter activity

Conditionally replicating adenoviruses (CRAds), or oncolytic adenoviruses, such as E1B55K-deleted adenovirus, are attractive anticancer agents. However, the therapeutic efficacy of E1B55K-deleted adenovirus for refractory solid tumors has been limited. Environmental stress conditions may induce nuclear accumulation of YB-1, which occurs in multidrug-resistant and adenovirus-infected cancer cells. Overexpression and nuclear localization of YB-1 are associated with poor prognosis and tumor recurrence in various cancers. Nuclear YB-1 transactivates the multidrug resistance 1 (MDR1) genes through the Y-box. Here, we developed a novel E1B55K-deleted adenovirus driven by the MDR1 promoter, designed Ad5GS3. We tested the feasibility of using YB-1 to transcriptionally regulate Ad5GS3 replication in cancer cells and thereby to enhance antitumor efficacy. We evaluated synergistic antitumor effects of oncolytic virotherapy in combination with chemotherapy. Our results show that adenovirus E1A induced E2F-1 activity to augment YB-1 expression, which shut down host protein synthesis in cancer cells during adenovirus replication. In cancer cells infected with Ad5WS1, an E1B55K-deleted adenovirus driven by the E1 promoter, E1A enhanced YB-1 expression, and then further phosphorylated Akt, which, in turn, triggered nuclear translocation of YB-1. Ad5GS3 in combination with chemotherapeutic agents facilitated nuclear localization of YB-1 and, in turn, upregulated the MDR1 promoter activity and enhanced Ad5GS3 replication in cancer cells. Thus, E1A, YB-1, and the MDR1 promoter form a positive feedback loop to promote Ad5GS3 replication in cancer cells, and this regulation can be further augmented when chemotherapeutic agents are added. In the in vivo study, Ad5GS3 in combination with etoposide synergistically suppressed tumor growth and prolonged survival in NOD/SCID mice bearing human lung tumor xenografts. More importantly, Ad5GS3 exerted potent oncolytic activity against clinical advanced lung adenocarcinoma, which was associated with elevated levels of nuclear YB-1 and cytoplasmic MDR1 expression in the advanced tumors. Therefore, Ad5GS3 may have therapeutic potential for cancer treatment, especially in combination with chemotherapy. Because YB-1 is expressed in a broad spectrum of cancers, this oncolytic adenovirus may be broadly applicable.

[YB-1-based virotherapy: A new therapeutic intervention for transitional cell carcinoma of the bladder?]

Therapeutic intervention using oncolytic viruses is called virotherapy. This type of virus is defined by the ability to replicate in tumor cells only and to destroy these cells upon replication. In addition, this virus type is able to induce a tumor-directed immune response. Early clinical trials have confirmed the safety profile of oncolytic viruses. Currently, different groups are working on the development of oncolytic viruses with a focus on treatment of nonmuscle invasive bladder cancer (NMIBC). A preliminary active recruiting clinical phase II/III trial ongoing in patients with a NMIBC was recently implemented in the United States. Our research group developed an oncolytic adenovirus that will soon enter a clinical phase I trial in patients diagnosed with glioma. This virus is being further modified for the treatment of NMIBC. In this review article, recent developments in the design and use of virotherapy in bladder cancer are summarized.

An armed, YB-1-dependent oncolytic adenovirus as a candidate for a combinatorial anti-glioma approach of virotherapy, suicide gene therapy and chemotherapeutic treatment

We investigated the novel recombinant oncolytic adenovirus Ad-delo-sr39TK-RGD, armed with a mutant herpes simplex virus type 1 thymidine kinase (HSV1-sr39TK) as a suicide gene, and explored its antitumor efficacy in combination with HSV1-sr39TK/ganciclovir (GCV) gene therapy and temozolomide (TMZ). Ad-delo-sr39TK-RGD is an E1-mutated conditionally replicating adenovirus dependent on the human Y-box binding protein 1 (YB-1). Thus, we utilized the YB-1 dependency of the vector to target human glioma cells in vitro, using two-dimensional cell culture and three-dimensional multicellular spheroids, and demonstrated the strong replication competence and oncolytic potential of the virus. The cytotoxicity mediated by HSV1-sr39TK and its prodrug GCV enhanced the oncolytic effect even at <0.1 μg ml(-1) GCV and induced cell killing of > 95% after adding GCV 0-1 days following infection. An increased bystander effect of viral replication and GCV in co-cultured infected and uninfected cells was observed. Co-administrating Ad-delo-sr39TK-RGD with TMZ and GCV, spheroid growth was reduced drastically. Gamma counting of infected spheroids demonstrated successful accumulation of the radiotracer (18)F-labeled 9-[4-fluoro-3-(hydroxymethyl)butyl]guanine mediated by HSV1-sr39TK. Hence, our results show that the combination of YB-1-dependent virotherapy with suicide genes and TMZ effectively induces glioma cell killing and may allow for in vivo non-invasive imaging within a limited time frame.

Establishment of a novel cell line for the enhanced production of recombinant adeno-associated virus vectors for gene therapy

Adeno-associated viral (AAV) vectors show great promise because of their excellent safety profile; however, pre-existing immune responses have necessitated the administration of high titer AAV, posing a significant challenge to the advancement of gene therapy involving AAV vectors. Recombinant AAV vectors contain minimum viral proteins necessary for their assembly and gene delivery functions. During the process of AAV assembly and production, AAV vectors acquire, inherently and submissively, various cellular proteins, but the identity of these proteins is poorly characterized. We reason that by identifying host cell proteins inherently associated with AAV vectors we may better understand the contribution of cellular components to AAV vector assembly and, ultimately, may improve the production of AAV vectors for gene therapy. In this study, three serotypes of recombinant AAV, namely AAV2, AAV5, and AAV8, were investigated. We used liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) methods to identify protein composition in purified AAV vectors, confirmed protein identities using western blotting, and explored the potential function of selected proteins in AAV vector production using small hairpin (shRNA) methods. Using LC-MS/MS, we identified 44 AAV-associated cellular proteins including Y-box binding protein (YB1). We showed for the first time that the establishment of a novel producer cell line by introducing an shRNA sequence down-regulating YB1 resulted in up to 45- and 9-fold increase in physical vector genome titers of AAV2 and AAV8, respectively, and up to 7-fold increase in AAV2 transduction vector genome titers. Our results revealed that YB1 gene knockdown promoted AAV2 rep expression and vector DNA production and reduced the number of empty particles in AAV2 products, suggesting that YB1 plays an important role in AAV vector assembly by competition with adenovirus E2A and AAV capsid proteins for binding to the inverted terminal repeat (ITR) sequence. The significance and implications of our findings in future improvement of AAV production are discussed.

The role of cold shock domain proteins in inflammatory diseases

Cold shock domain proteins are characterized by the presence of one or more evolutionarily conserved cold shock domains, which each possess two nucleic acid-binding motifs. These proteins exert pleiotropic functions in cells via their ability to bind single-stranded RNA and/or DNA, thus allowing them to serve as transcriptional as well as translational regulators. Not only can they regulate their own expression, but they also regulate the expression of a number of pro- and anti-inflammatory cytokines, as well as cytokine receptors, making them key players in the orchestration of inflammatory processes and immune cell phenotypes. To add to their complexity, the expression of cold shock domain proteins is induced by cellular stress. At least one cold shock domain protein is actively secreted and binds to specific cell surface receptors, thereby influencing the proliferative and migratory capacity of the cell. The presence of cold shock domain proteins in the blood and/or urine of patients with cancer or inflammatory disease, as well as the identification of autoantibodies directed against these proteins make them potential targets of therapeutic interest.

Y-box binding protein 1--a prognostic marker and target in tumour therapy

Y-box binding protein 1 (YB-1) is a multifunctional protein involved in various cellular processes including both transcriptional and translational regulation of target gene expression. Significantly increased YB-1 levels have been reported in a number of human malignancies and shown to be associated with poor prognosis and disease recurrence. Indeed, YB-1 can act as a versatile oncoprotein playing an important role in tumour cell proliferation and progression. Consequently, YB-1 not only proves to be a good prognostic tumour marker, but also may be a promising emerging molecular target for the development of new therapeutical strategies. In this review, we discuss both the role of YB-1 in cancer and specifically in malignant melanoma as well as possible translations into the clinics derived thereof.

YBX1 is a modulator of MIA/CD-RAP-dependent chondrogenesis

MIA/CD-RAP is a small, secreted protein involved in cartilage differentiation and melanoma progression. We recently revealed that p54(nrb) acts as a mediator of MIA/CD-RAP action to promote chondrogenesis and the progression of malignant melanoma. As the molecular mechanism of MIA/CD-RAP action in cartilage has not been defined in detail until now, we aimed to understand the regulation of p54(nrb) transcription in chondrogenesis. We concentrated on the previously described MIA/CD-RAP-dependent regulatory region in the p54(nrb) promoter and characterized the transcriptional regulation of p54(nrb) by MIA/CD-RAP in cartilage. A series of truncated p54(nrb) promoter constructs and mutagenesis analysis revealed that the transcription factor YBX1, which has not been investigated in chondrogenesis thus far, is the mediator of MIA/CD-RAP dependent activation of p54(nrb) transcription. A systematic analysis of genes carrying this binding site in their promoter region revealed further potential MIA/CD-RAP-regulated genes that have been implicated in cartilage differentiation. In summary, we described the effects of MIA/CD-RAP on transcriptional regulation in chondrocytes. Understanding the regulation of p54(nrb) via YBX1 contributes to the understanding of chondrogenesis. Uncovering new downstream effectors that function via the activation of YBX1 supports the important role of MIA/CD-RAP in these processes.

YB-1 dependent oncolytic adenovirus efficiently inhibits tumor growth of glioma cancer stem like cells

Background

The brain cancer stem cell (CSC) model describes a small subset of glioma cells as being responsible for tumor initiation, conferring therapy resistance and tumor recurrence. In brain CSC, the PI3-K/AKT and the RAS/mitogen activated protein kinase (MAPK) pathways are found to be activated. In consequence, the human transcription factor YB-1, knowing to be responsible for the emergence of drug resistance and driving adenoviral replication, is phosphorylated and activated. With this knowledge, YB-1 was established in the past as a biomarker for disease progression and prognosis. This study determines the expression of YB-1 in glioblastoma (GBM) specimen in vivo and in brain CSC lines. In addition, the capacity of Ad-Delo3-RGD, an YB-1 dependent oncolytic adenovirus, to eradicate CSC was evaluated both in vitro and in vivo.

Methods

YB-1 expression was investigated by immunoblot and immuno-histochemistry. In vitro, viral replication as well as the capacity of Ad-Delo3-RGD to replicate in and, in consequence, to kill CSC was determined by real-time PCR and clonogenic dilution assays. In vivo, Ad-Delo3-RGD-mediated tumor growth inhibition was evaluated in an orthotopic mouse GBM model. Safety and specificity of Ad-Delo3-RGD were investigated in immortalized human astrocytes and by siRNA-mediated downregulation of YB-1.

Results

YB-1 is highly expressed in brain CSC lines and in GBM specimen. Efficient viral replication in and virus-mediated lysis of CSC was observed in vitro. Experiments addressing safety aspects of Ad-Delo3-RGD showed that (i) virus production in human astrocytes was significantly reduced compared to wild type adenovirus (Ad-WT) and (ii) knockdown of YB-1 significantly reduced virus replication. Mice harboring othotopic GBM developed from a temozolomide (TMZ)-resistant GBM derived CSC line which was intratumorally injected with Ad-Delo3-RGD survived significantly longer than mice receiving PBS-injections or TMZ treatment.

Conclusion

The results of this study supported YB-1 based virotherapy as an attractive therapeutic strategy for GBM treatment which will be exploited further in multimodal treatment concepts.

Melanoma inhibitory activity promotes melanoma development through activation of YBX1

Melanoma inhibitory activity (MIA), a small soluble secreted protein, is functionally important for progression of malignant melanoma. We recently revealed that p54(nrb) acts as a mediator of MIA action. In this study, we characterize the transcriptional regulation of p54(nrb) by MIA to explain MIA's molecular action. We identified one highly conserved region in the p54(nrb) promoter that is necessary and sufficient for MIA-dependent activation. Functional promoter analysis identified the transcription factor YBX1 as the mediator of MIA activation of p54(nrb) transcription. We screened the genome for further potential MIA-regulated genes carrying the element in their promoter regions. Integrating our sequence data with expression data from human melanomas identified a list of 23 potential MIA-YBX1 targets in melanomas. In summary, we present for the first time effects of MIA on transcriptional regulation. Uncovering new potential downstream effectors working via activation of YBX1 supports the important role of MIA in melanoma.

Y-box-binding protein 1 (YB-1) and its functions

This review describes the structure and functions of Y-box binding protein 1 (YB-1) and its homologs. Interactions of YB-1 with DNA, mRNAs, and proteins are considered. Data on the participation of YB-1 in DNA reparation and transcription, mRNA splicing and translation are systematized. Results on interactions of YB-1 with cytoskeleton components and its possible role in mRNA localization are discussed. Data on intracellular distribution of YB-1, its redistribution between the nucleus and the cytoplasm, and its secretion and extracellular functions are summarized. The effect of YB-1 on cell differentiation, its involvement in extra- and intracellular signaling pathways, and its role in early embryogenesis are described. The mechanisms of regulation of YB-1 expression in the cell are presented. Special attention is paid to the involvement of YB-1 in oncogenic cell transformation, multiple drug resistance, and dissemination of tumors. Both the oncogenic and antioncogenic activities of YB-1 are reviewed. The potential use of YB-1 in diagnostics and therapy as an early cancer marker and a molecular target is discussed.

Formation of amyloid-like fibrils by Y-box binding protein 1 (YB-1) is mediated by its cold shock domain and modulated by disordered terminal domains

YB-1, a multifunctional DNA- and RNA-binding nucleocytoplasmic protein, is involved in the majority of DNA- and mRNA-dependent events in the cell. It consists of three structurally different domains: its central cold shock domain has the structure of a β-barrel, while the flanking domains are predicted to be intrinsically disordered. Recently, we showed that YB-1 is capable of forming elongated fibrils under high ionic strength conditions. Here we report that it is the cold shock domain that is responsible for formation of YB-1 fibrils, while the terminal domains differentially modulate this process depending on salt conditions. We demonstrate that YB-1 fibrils have amyloid-like features, including affinity for specific dyes and a typical X-ray diffraction pattern, and that in contrast to most of amyloids, they disassemble under nearly physiological conditions.

Association of nuclear YB-1 localization with lung resistance-related protein and epidermal growth factor receptor expression in lung cancer

BACKGROUND

Y-box binding protein 1 (YB-1) is an oncogenic transcription factor that is activated in response to various genotoxic stresses. The purpose of this study was to elucidate whether YB-1 correlates with the expression of lung resistance-related protein (LRP) and epidermal growth factor receptor (EGFR) in primary lung cancer.

PATIENTS AND METHODS

One hundred and five non-small-cell lung cancer (NSCLC) specimens were analyzed by immunohistochemistry. Knockdown of YB-1 messenger RNA by small interfering RNA(siRNA) was tested for the lung cancer cell lines A549 and Calu-3.

RESULTS

Nuclear YB-1 expression significantly correlated with positive LRP and EGFR expression (P < .001). Nuclear YB-1 expression and positive LRP and EGFR expression were independent adverse prognostic factors in patients with NSCLC. Furthermore, patients with tumors positive for nuclear YB-1 and LRP had a significantly worse prognosis than those negative for nuclear YB-1 and LRP (P < .001). In addition, patients with tumors positive for nuclear YB-1 and EGFR had a significantly worse prognosis than those negative for nuclear YB-1 and EGFR (P < .001). In in vitro analyses that use the NSCLC cell lines A549 and Calu-3, the downregulation of YB-1 with siRNAs drastically decreased the expression of EGFR. However, downregulation of YB-1 remarkably decreased the expression of LRP in A549 cells; however, a slight decrease in LRP was induced by the downregulation of YB-1 in Calu-3 cells.

CONCLUSION

Our data demonstrate that nuclear YB-1 localization is associated with LRP and EGFR expression in NSCLC, and nuclear YB-1 localization and LRP and EGFR expression are of prognostic significance in NSCLC.

Identification of a previously unrecognized promoter that drives expression of the UXP transcription unit in the human adenovirus type 5 genome

We previously identified an adenovirus (Ad) protein named U exon protein (UXP) encoded by a leftward-strand (l-strand) transcription unit. Here we identify and characterize the UXP promoter. Primer extension and RNase protection assays mapped the transcription initiation site at 32 nucleotides upstream of the UXP gene initiation codon. A series of viral mutants with mutations at two putative inverted CCAAT (I-CCAAT) boxes and two E2F sites were generated. With mutants lacking the proximal I-CCAAT box, the UXP mRNA level decreased significantly to 30% of the Ad type 5 (Ad5) mRNA level as measured by quantitative reverse transcription-PCR. Decreased UXP was also observed by immunoblotting and immunofluorescence. UXP mRNA and protein levels were similar to those of Ad5 for mutants lacking the distal I-CCAAT box or both putative E2F sites. Ad DNA levels were similar in mutant- and wild-type Ad5-infected cells during the late stage of infection, strongly suggesting that the decreased UXP mRNA and protein from mutants lacking the proximal I-CCAAT box was due to decreased promoter activity. Electrophoretic mobility shift assays (EMSA) indicated that a cellular factor binds specifically to the proximal I-CCAAT box of the UXP promoter. An in vitro luciferase reporter assay demonstrated that basal promoter activity lies between bp -158 and +30 of the transcription initiation site. No E1A-mediated promoter transactivation was observed in 293 cells compared with A549 cells. Thus, we propose that there is a previously unidentified Ad5 promoter that drives expression of the UXP transcription unit. This promoter is embedded within the gene for fiber, and it contains a proximal I-CCAAT box critical for UXP mRNA transcription.

Proteomic analyses of the effects of drugs of abuse on monocyte-derived mature dendritic cells

Drug abuse has become a global health concern. Understanding how drug abuse modulates the immune system and how the immune system responds to pathogens associated with drug abuse, such hepatitis C virus (HCV) and human immunodeficiency virus (HIV-1), can be assessed by an integrated approach comparing proteomic analyses and quantitation of gene expression. Two-dimensional (2D) difference gel electrophoresis was used to determine the molecular mechanisms underlying the proteomic changes that alter normal biological processes when monocyte-derived mature dendritic cells were treated with cocaine or methamphetamine. Both drugs differentially regulated the expression of several functional classes of proteins including those that modulate apoptosis, protein folding, protein kinase activity, and metabolism and proteins that function as intracellular signal transduction molecules. Proteomic data were validated using a combination of quantitative, real-time PCR and Western blot analyses. These studies will help to identify the molecular mechanisms, including the expression of several functionally important classes of proteins that have emerged as potential mediators of pathogenesis. These proteins may predispose immunocompetent cells, including dendritic cells, to infection with viruses such as HCV and HIV-1, which are associated with drug abuse.

Effects of acupuncture on expressions of the transcription factors NF-E2, YB-1, LRG47 in the SAMP10 mice

OBJECTIVE

To explore the mechanism of acupuncture for delaying aging.

METHODS

Using the senescence accelerated mouse pattern SAMP10 and the normal aging mice SAMR1 as models and applying RT-PCR and digoxin (DIG)-labeled Northern blot technique to observe expressions of NF-E2, YB-1, LRG47 genes in the forebrain, cortex and hippocampus in a 8-month old SAMR1 control group, a 8-month old SAMP10 control group, a 8-month old SAMP10 acupuncture group and a 8-month old SAMP10 non-point stimulation group.

RESULTS

In the SAMP10 control group, the expressions of NF-E2, YB-1 and LRG47 were down-regulated in the forebrain, cortex and hippocampus, and after acupuncture they were up-regulated and tended to normal.

CONCLUSION

The brain aging of the SAMP10 mice is related with abnormal expressions of NF-E2, YB-1 and LRG47 genes; and acupuncture can regulate the expressions of NF-E2, YB-1 and LRG47 genes, strengthening the functions of erythrocyte series, increasing the proliferation of cells and enhancing the cellular immune function in anti-bacteria, hence delaying aging.

[YB-1 as a potential target in cancer therapy]

The 42-kDa multifunctional cellular protein Y-box protein 1 (YB-1) is expressed in various cancers. It is localized in the cytoplasm as well as in the nucleus. In particular, YB-1 is localized in the nuclear compartment following cellular stress, such as radiation, drug treatment, hyperthermia, or viral infection. Within the nucleus, YB-1 can act as a transcription factor, and it is involved in the regulation of important cancer-associated genes. For example, YB-1 triggers the expression of Her-2 and estrogen receptor alpha (ERalpha) in breast cancer. Thus, nuclear YB-1 appears to be a potential target for the inhibition of Her-2- and ERalpha-dependent proliferation signals, particularly with regard to resistance to Her-2-targeting drugs such as trastuzumab. In some cancers, YB-1 may be involved in regulating MDR1/P-glycoprotein, mediating classical multidrug resistance (MDR). Furthermore, YB-1 is involved in the replication of adenovirus type 5, a commonly used vector in gene therapy. Thus, YB-1 can trigger an "oncolytic" effect in YB-1 nuclear positive cancer cells treated with adenoviruses. Besides its impact as a prognostic factor, in the future the diagnostics of cellular YB-1 status may provide the basis for a virotherapy or a gene therapy incorporating adenoviruses.

Designing adenoviral vectors for tumor-specific targeting

Adenovirus provides an attractive candidate tool to destroy tumor cells. However, to fulfill the expectations, selective targeting of tumor cells is mandatory. This chapter reviews critical aspects in the design of tumor-targeted adenovirus vectors and oncolytic adenoviruses. The review focuses on genetic modifications of capsid and regulatory genes that can enhance the therapeutic index of these agents after systemic administration. Selectivity will be considered at different levels: biodistribution selectivity of the injected virus particles, transductional selectivity defined as cell receptor interactions and trafficking that lead to virus gene expression, transcriptional selectivity by means of tumor-selective promoters, and mutation-rescue selectivity to achieve selective replication. Proper assays to analyze selectivity at these different levels are discussed. Finally, mutations and transgenes that can enhance the potency and efficacy of tumor-targeted adenoviruses from virocentric or immunocentric points of view will be presented.