Y-box binding protein 1--a prognostic marker and target in tumour therapy. Eur J Cell Biol. 2014;93:61-70. [PMID: 24461929 DOI: 10.1016/j.ejcb.2013.11.007]

Gene signatures of m5C regulators may predict prognosis and immunity status of patients with Ewing's sarcoma

Recent studies have showed that 5-methylcytosine (m5C) can be utilized to assess the prognosis of tumors. However, the role of clinical implications of m5C modification remains unclear. The mRNA expression profiles and clinical features were downed from GEO and ICGC databases.In order to screen out m5C regulators,Univariate and multivariate Cox regression were performed. The survival rate was determined using K-M survival analysis. Then the risk model was validated in ICGC and GSE63156 two external datasets. A nomogram was created using risk level and clinical features, well validated by calibration curve. ESTIMATE, MCP-counter and GSVA algorithms were applied to assess tumor microenvironment, immune cell, and immune function. Several drugs exhibited sensitivity for potential therapy of ES. Five m5C regulators (YBX1, TET2, NOP2, DNMT3A, DNMT1) were screened out as risk signatures. The Kaplan-Meier survival analysis demonstrated that the high-risk group had a lower survival rate compared to the low-risk group(p = 0.0026). The AUC of ROC curves in 1, 3, 5 years ranged from 0.752 to 0.829. Based on the amount of risk and clinical characteristics, a nomogram was created and well validated by calibration curve.ESTIMATE, MCP-counter and GSVA algorithms were applied to assess tumor mircoenvironment, immune cell, and immune function. Several drugs exhibited sensitivity for potential therapy of ES. The present research indicated that m5C regulators (YBX1, TET2, NOP2, DNMT3A, DNMT1) play critical roles in ES progression, and provide new insight in ES prognosis prediction.

YB-1 Targeted by miR-509-3-5p Affects Migration and Invasion of Triple‑Negative Breast Cancer by Regulating Cellular Epithelial‑Mesenchymal Transition

The epithelial-mesenchymal transition (EMT) process is closely linked to metastasis of breast cancer. This article elucidates the role of Y-box binding protein-1 (YB-1) on the migration and invasion of triple-negative breast cancer (TNBC) cells by regulating EMT, and the related mechanism. The expression data of YB-1 and miR-509-3-5p in TNBC samples and normal samples were downloaded from the GEO database. The proliferation, migration, invasion, and EMT of TNBC cells were detected by CCK-8 assay, colony formation assay, wound-healing assay, transwell assay, and immunoblotting analyses. The targeted binding of YB-1 and miR-509-3-5p was validated by luciferase reporter experiment. A xenograft mouse model was constructed to investigate the influence of the miR-509-3-5p/YB-1 axis on TNBC tumor growth in vivo. YB-1 was overexpressed, while miR-509-3-5p was underexpressed in TNBC tumor tissues and various cell lines. Silencing YB-1 depressed cell viability, proliferation, motility, and EMT in vitro, and miR-509-3-5p upregulation exerted the same effects. YB-1 was targeted by miR-509-3-5p. The suppressive effects on the phenotypes of TNBC cells caused by overexpressed miR-509-3-5p were attenuated by YB-1 upregulation. In addition, miR-509-3-5p overexpression restrained TNBC tumor growth and downregulated the YB-1-mediated EMT process in vivo. YB-1 targeted by miR-509-3-5p affects motility of TNBC cells by regulating cellular EMT.

YB1 and its role in osteosarcoma: a review

YB1 (Y box binding protein 1), a multifunctional protein capable of binding to DNA/RNA, is present in most cells and acts as a splicing factor. It is involved in numerous cellular processes such as transcription, translation, and DNA repair, significantly affecting cell proliferation, differentiation, and apoptosis. Abnormal expression of this protein is closely linked to the formation of various malignancies (osteosarcoma, nasopharyngeal carcinoma, breast cancer, etc.). This review examines the multifaceted functions of YB1 and its critical role in osteosarcoma progression, providing new perspectives for potential therapeutic strategies.

Y-box binding protein 1/cyclin A1 axis specifically promotes cell cycle progression at G2/M phase in ovarian cancer

Y-box binding protein 1 (YBX1) promotes oncogenic transformation and tumor growth. YBX1 plays a role in regulation of cell cycle promotion via upregulation of cell cycle-related genes. In ovarian cancer, YBX1 also promotes tumor growth, but the mechanisms of YBX1 in cell growth and cell cycle in ovarian cancer remain not to be fully understood. Here, we investigated whether YBX1-dependent cancer cell proliferation was specifically associated with expression of cell cycle related genes in ovarian cancer. Protein and mRNA expression levels of YBX1 and cell cycle-related genes in ovarian cancer cell lines and tissues were determined by western blot analysis, immunohistochemical analysis and reverse transcription-quantitative PCR. Cell cycle analysis was performed by flow cytometry. Luciferase assay and Chromatin immunoprecipitation assay were used to investigate a transcriptional function of YBX1. YBX1 silencing induced marked growth suppression in 4 cell lines (group A), moderate suppression in 5 cell lines (group B), and no suppression in 3 cell lines (group C) among 12 ovarian cancer cell lines in culture. The YBX1 silencing induced cell cycle arrest at G2/M phase and suppressed expression of cyclin A1 gene in group A and B cell lines, but not in group C cell lines. Cyclin A1 silencing specifically suppressed cell proliferation in group A cell lines and partially in group B cell lines, but not at all in group C cell lines. YBX1 mRNA levels were significantly correlated with cyclin A1 mRNA levels in patients with high-grade serous carcinoma. Augmented YBX1 expression plays a key role in tumor growth promotion in ovarian cancer in its close association with cyclin A1.

Multi-omic analyses of m5C readers reveal their characteristics and immunotherapeutic proficiency

5-methylcytosine (m5C) is a post-transcriptional RNA modification identified, m5C readers can specifically identify and bind to m5C. ALYREF and YBX1 as members of m5C readers that have garnered increasing attention in cancer research. However, comprehensive analysis of their molecular functions across pancancer are lacking. Using the TCGA and GTEx databases, we investigated the expression levels and prognostic values of ALYREF and YBX1. Additionally, we assessed the tumor microenvironment, immune checkpoint-related genes, immunomodulators, Tumor Immune Dysfunction and Exclusion (TIDE) score and drug resistance of ALYREF and YBX1. Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and Gene Set Enrichment Analysis (GSEA) analyses were performed to investigate the potential functions associated with m5C readers and coexpressed genes. Aberrant expression of ALYREF and YBX1 was observed and positively associated with prognosis in KIRP, LGG and LIHC. Furthermore, the expression levels of ALYREF and YBX1 were significantly correlated with immune infiltration of the tumor microenvironment and immune-related modulators. Last, our analysis revealed significant correlations between ALYREF, YBX1 and eIFs. Our study provides a substantial understanding of m5C readers and the intricate relationship between ALYREF, YBX1, eIFs, and mRNA dynamics. Through multidimensional analysis of immune infiltration and drug sensitivity/resistance in ALYREF and YBX1, we propose a possibility for combined modality therapy utilizing m5C readers.

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.

YBX1, Targeted By Microrna-382-5p, Promotes Laryngeal Squamous Cell Carcinoma Progression via Modulating RAS/MAPK Signaling

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) is the most common cancer of head and neck cancer. Y-box binding protein-1 (YBX1) has tumor-promoting effects in some types of cancers. However, its role in LSCC remains unknown. This study set out to identify the role of YBX1 in LSCC.

METHODS

Bioinformatics analysis of the Gene Expression Omnibus (GEO) database and our cohort data were used to explore the association of YBX1 expression with clinicopathological factors in LSCC. Then, cells with stably or transiently transfected with plasmid or siRNA were constructed to assess the effect of loss and gain of YBX1 on the biological phenotypes of LSCC cells in vitro. In addition, subcutaneous xenograft and orthotopic liver tumor mouse models were constructed for validation. The interrogated miRNA databases and subsequent luciferase reporter assays were used to confirm the miR-382-5p target of YBX1. At last, KEGG enrichment annotation from TGCA data was used for downstream analyses of miR-382-5p/YBX1 and verified by PCR and Western immunoblotting.

RESULTS

The results showed that significant upregulation of YBX1 in LSCC tumors was correlated with advanced TNM stage and poor prognosis. Knockdown of YBX1 markedly impaired the proliferative, invasive, and migratory activity of Tu212 cells. We confirmed that miR-382-5p targets YBX1 to mediate LSCC progression both in vitro and in vivo. We further confirmed that miR-382-5p/YBX1 modulated the Ras/MAPK signaling axis to regulate the progression of LSCC.

CONCLUSION

Together, our results indicated that YBX1 is an important promoter of LSCC progression. And miR-382-5p/YBX1/RAS/MAPK signaling pathway can be perceived as a promising target in the treatment of LSCC.

Y-box protein-1 modulates circSPECC1 to promote glioma tumorigenesis via miR-615-5p/HIP1/AKT axis

Y-box binding protein-1 (YB-1) is upregulated in glioma and plays an important role in its occurrence and drug resistance. However, the involved regulatory processes and downstream pathways are still unclear. Since various circular RNAs (circRNAs) and microRNAs (miRNAs) also play roles in the pathogenesis of glioma, we hypothesize that YB-1 may exert its function through a circRNA-miRNA-protein interaction network. In this study, we use the RNA binding protein immunoprecipitation assay and quantitative reverse transcription polymerase chain reaction to determine the circRNAs involved in the regulation of YB-1 and further elucidate their biological functions. The level of circSPECC1 (hsa_circ_0000745) modulated by YB-1 is significantly upregulated in the U251 and U87 glioma cell lines. Downregulation of circSPECC1 markedly inhibits the proliferation and invasiveness of U251 and U87 cells by inducing apoptosis. Bioinformatics analysis reveals that miR-615-5p could interact with circSPECC1 and huntingtin-interacting protein-1 (HIP-1). Then we determine the interactions between miR-615-5p, circSPECC1, and HIP1 using dual luciferase reporter system and pull-down assays. Mechanistic analysis indicates that the downregulation of circSPECC1 results in a decreased HIP1 expression. This study demonstrates that circSPECC1 modulated by YB-1 is increased in glioma cell lines. In addition, circSPECC1 promotes glioma growth through the upregulation of HIP1 by sponging miR-615-5p and targeting the HIP1/AKT pathway. This indicates that YB-1 and circSPECC1 may both be promising targets for glioma treatment.

YB-1 activating cascades as potential targets in KRAS-mutated tumors

Y‑box binding protein‑1 (YB-1) is a multifunctional protein that is highly expressed in human solid tumors of various entities. Several cellular processes, e.g. cell cycle progression, cancer stemness and DNA damage signaling that are involved in the response to chemoradiotherapy (CRT) are tightly governed by YB‑1. KRAS gene with about 30% mutations in all cancers, is considered the most commonly mutated oncogene in human cancers. Accumulating evidence indicates that oncogenic KRAS mediates CRT resistance. AKT and p90 ribosomal S6 kinase are downstream of KRAS and are the major kinases that stimulate YB‑1 phosphorylation. Thus, there is a close link between the KRAS mutation status and YB‑1 activity. In this review paper, we highlight the importance of the KRAS/YB‑1 cascade in the response of KRAS-mutated solid tumors to CRT. Likewise, the opportunities to interfere with this pathway to improve CRT outcome are discussed in light of the current literature.

Biomechanical and biochemical assessment of YB-1 expression in A375 melanoma cell line: Exploratory study

Malignant melanoma is the most lethal form of skin cancer. Y-box binding protein 1 (YB-1) plays a prominent role in mediating metastatic behavior by promoting epithelial-to-mesenchymal transition (EMT). Migratory melanoma cells exhibit two major migration modes: elongated mesenchymal or rounded amoeboid. Using A375 melanoma cell line and the YB-1 knock-out model, we aimed to elucidate biochemical and biomechanical changes in migration signaling pathways in the context of melanoma metastases. We subjected A375 YB-1 knock-out and parental cells to atomic force microscopy (stiffness determination), immunolabelling, and proteome analysis. We found that YB-1 expressing cells were significantly stiffer compared to the corresponding YB-1 knock-out cell line. Our study demonstrated that the constitutive expression of YB-1 in A375 melanoma cell line appears to be closely related to known biomarkers of epithelial-to-mesenchymal transition, nestin, and vimentin, resulting in a stiffer phenotype, as well as a wide array of proteins involved in RNA, ribosomes, and spliceosomes. YB-1 knock-out resulted in nestin depletion and significantly lower vimentin expression, as well as global upregulation of proteins related to the cytoskeleton and migration. YB-1 knock-out cells demonstrated both morphological features and biochemical drivers of mesenchymal/ameboid migration. Melanoma is a highly plastic, adaptable, and aggressive tumor entity, capable of exhibiting characteristics of different migratory modes.

Targeting K-Ras-mediated DNA damage response in radiation oncology: Current status, challenges and future perspectives

Approximately 60% of cancer patients receive curative or palliative radiation. Despite the significant role of radiotherapy (RT) as a curative approach for many solid tumors, tumor recurrence occurs, partially because of intrinsic radioresistance. Accumulating evidence indicates that the success of RT is hampered by activation of the DNA damage response (DDR). The intensity of DDR signaling is affected by multiple parameters, e.g., loss-of-function mutations in tumor suppressor genes, gain-of-function mutations in protooncogenes as well as radiation-induced alterations in signal-transduction pathways. Therefore, the response to irradiation differs in tumors of different types, which makes the individualization of RT as a rational but challenging goal. One contributor to tumor cell radiation survival is signaling through the Ras pathway. Three RAS genes encode 4 Ras isoforms: K-Ras4A, K-Ras4B, H-Ras, and N-Ras. RAS family members are found to be mutated in approximately 19% of human cancers. Mutations in RAS lead to constitutive activation of the gene product and activation of multiple Ras-dependent signal-transduction cascades. Preclinical studies have shown that the expression of mutant KRAS affects DDR and increases cell survival after irradiation. Approximately 70% of RAS mutations occur in KRAS. Thus, applying targeted therapies directly against K-Ras as well as K-Ras upstream activators and downstream effectors might be a tumor-specific approach to overcome K-Ras-mediated RT resistance. In this review, the role of K-Ras in the activation of DDR signaling will be summarized. Recent progress in targeting DDR in KRAS-mutated tumors in combination with radiochemotherapy will be discussed.

The Oncolytic Adenovirus XVir-N-31, in Combination with the Blockade of the PD-1/PD-L1 Axis, Conveys Abscopal Effects in a Humanized Glioblastoma Mouse Model

Glioblastoma (GBM) is an obligatory lethal brain tumor with a median survival, even with the best standard of care therapy, of less than 20 months. In light of this fact, the evaluation of new GBM treatment approaches such as oncolytic virotherapy (OVT) is urgently needed. Based on our preliminary preclinical data, the YB-1 dependent oncolytic adenovirus (OAV) XVir-N-31 represents a promising therapeutic agent to treat, in particular, therapy resistant GBM. Preclinical studies have shown that XVir-N-31 prolonged the survival of GBM bearing mice. Now using an immunohumanized mouse model, we examined the immunostimulatory effects of XVir-N-31 in comparison to the wildtype adenovirus (Ad-WT). Additionally, we combined OVT with the inhibition of immune checkpoint proteins by using XVir-N-31 in combination with nivolumab, or by using a derivate of XVir-N-31 that expresses a PD-L1 neutralizing antibody. Although in vitro cell killing was higher for Ad-WT, XVir-N-31 induced a much stronger immunogenic cell death that was further elevated by blocking PD-1 or PD-L1. In vivo, an intratumoral injection of XVir-N-31 increased tumor infiltrating lymphocytes (TILs) and NK cells significantly more than Ad-WT not only in the virus-injected tumors, but also in the untreated tumors growing in the contralateral hemisphere. This suggests that for an effective treatment of GBM, immune activating properties by OAVs seem to be of greater importance than their oncolytic capacity. Furthermore, the addition of immune checkpoint inhibition (ICI) to OVT further induced lymphocyte infiltration. Consequently, a significant reduction in contralateral non-virus-injected tumors was only visible if OVT was combined with ICI. This strongly indicates that for an effective eradication of GBM cells that cannot be directly targeted by an intratumoral OV injection, additional ICI therapy is required.

The C-Terminal Domain of Y-Box Binding Protein 1 Exhibits Structure-Specific Binding to Poly(ADP-Ribose), Which Regulates PARP1 Activity

Y-box-binding protein 1 (YB-1) is a multifunctional protein involved in the regulation of gene expression. Recent studies showed that in addition to its role in the RNA and DNA metabolism, YB-1 is involved in the regulation of PARP1 activity, which catalyzes poly(ADP-ribose) [PAR] synthesis under genotoxic stress through auto-poly(ADP-ribosyl)ation or protein trans-poly(ADP-ribosyl)ation. Nonetheless, the exact mechanism by which YB-1 regulates PAR synthesis remains to be determined. YB-1 contains a disordered Ala/Pro-rich N-terminal domain, a cold shock domain, and an intrinsically disordered C-terminal domain (CTD) carrying four clusters of positively charged amino acid residues. Here, we examined the functional role of the disordered CTD of YB-1 in PAR binding and in the regulation of PARP1-driven PAR synthesis in vitro. We demonstrated that the rate of PARP1-dependent synthesis of PAR is higher in the presence of YB-1 and is tightly controlled by the interaction between YB-1 CTD and PAR. Moreover, YB-1 acts as an effective cofactor in the PAR synthesis catalyzed by the PARP1 point mutants that generate various PAR polymeric structures, namely, short hypo- or hyperbranched polymers. We showed that either a decrease in chain length or an increase in branching frequency of PAR affect its binding affinity for YB-1 and YB-1-mediated stimulation of PARP1 enzymatic activity. These results provide important insight into the mechanism underlying the regulation of PARP1 activity by PAR-binding proteins containing disordered regions with clusters of positively charged amino acid residues, suggesting that YB-1 CTD-like domains may be considered PAR "readers" just as other known PAR-binding modules.

Long non-coding RNAs involved in different steps of cancer metastasis

Non-proteincoding transcripts bearing 200 base pairs known as long non-coding RNAs (lncRNAs) play a role in a variety of molecular mechanisms, including cell differentiation, apoptosis and metastasis. Previous studies have suggested that frequently dysregulated lncRNAs play a crucial role in various aspects of cancer metastasis. Metastasis is the main leading cause of death in cancer. The role of lncRNAs in different stages of metastasis is the subject of this review. Based on in vitro and in vivo investigations on metastasis, we categorized lncRNAs into distinct stages of metastasis including angiogenesis, invasion, intravasation, survival in circulation, and extravasation. The involvement of lncRNAs in angiogenesis and invasion has been extensively studied. Here, we comprehensively discuss the role and functions of these lncRNAs with a particular focus on the molecular mechanisms.

Copy number amplification and SP1-activated lncRNA MELTF-AS1 regulates tumorigenesis by driving phase separation of YBX1 to activate ANXA8 in non-small cell lung cancer

Long non-coding RNAs (lncRNAs) are reported to play key roles in tumorigenesis. However, the mechanisms underlying lncRNA-mediated regulation of RNA-binding protein phase separation in tumorigenesis have not been completely elucidated. In this study, an oncogenic lncRNA MELTF-AS1 was identified using systematic data analysis, screening, and verification. MELTF-AS1 was markedly upregulated in non-small cell lung cancer (NSCLC). High MELTF-AS1 levels were associated with advanced tumor-node-metastasis stage (TNM), high tumor size, and decreased survival time. Functionally, MELTF-AS1 regulated cell proliferation and metastasis in vitro and in vivo. RNA sequencing analysis revealed that MELTF-AS1 knockdown specifically modulated genes associated with cell proliferation, apoptosis, and migration. Mechanistically, at the genome level, copy number amplification promoted MELTF-AS1 expression. At the transcriptional level, the transcription factor SP1 directly activated MELTF-AS1 transcription by binding to its promoter. Furthermore, MELTF-AS1 could directly bind and drive the phase separation of YBX1, which was an RNA-binding protein and involved in tumorigenesis, thus activating ANXA8 transcription and promoting tumorigenesis of NSCLC. Aberrant activation of ANXA8 and promotion of tumorigenesis have been found in a variety of tumors. These novel findings demonstrated the critical role of MELTF-AS1-driven phase separation-mediated transcriptional regulation and provided a potential novel diagnostic and therapeutic target for NSCLC.

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.

Role of Y-Box Binding Proteins in Ontogenesis

Y-box binding proteins (YB proteins) are multifunctional DNA/RNA-binding proteins capable of regulating gene expression at multiple levels. At present, the most studied function of these proteins is the regulation of protein synthesis. Special attention in this review has been paid to the role of YB proteins in the control of mRNA translation and stability at the earliest stages of organism formation, from fertilization to gastrulation. Furthermore, the functions of YB proteins in the formation of germ cells, in which they accumulate in large amounts, are summarized. The review then discusses the contribution of YB proteins to the regulation of gene expression during the differentiation of various types of somatic cells. Finally, future directions in the study of YB proteins and their role in ontogenesis are considered.

Role of YB-1 in Regulation of Poly(ADP-Ribosylation) Catalyzed by Poly(ADP-Ribose) Polymerases

Poly(ADP-ribosyl)ation is a post-translational modification of proteins that performs an essential regulatory function in the cellular response to DNA damage. The key enzyme synthesizing poly(ADP-ribose) (PAR) in the cells is poly(ADP-ribose) polymerase 1 (PARP1). Understanding the mechanisms of the PARP1 activity regulation within the cells is necessary for development of the PARP1-targeted antitumor therapy. This review is devoted to the studies of the role of the RNA-binding protein YB-1 in the PARP1-catalyzed PARylation. The mechanisms of PARP1 activity stimulation by YB-1 protein can possibly be extended to other RNA-binding proteins involved in the maintenance of the genome stability.

YB-1 Phosphorylation at Serine 209 Inhibits Its Nuclear Translocation

YB-1 is a multifunctional DNA- and RNA-binding protein involved in cell proliferation, differentiation, and migration. YB-1 is a predominantly cytoplasmic protein that is transported to the nucleus in certain conditions, including DNA-damaging stress, transcription inhibition, and viral infection. In tumors, YB-1 nuclear localization correlates with high aggressiveness, multidrug resistance, and a poor prognosis. It is known that posttranslational modifications can regulate the nuclear translocation of YB-1. In particular, well-studied phosphorylation at serine 102 (S102) activates YB-1 nuclear import. Here, we report that Akt kinase phosphorylates YB-1 in vitro at serine 209 (S209), which is located in the vicinity of the YB-1 nuclear localization signal. Using phosphomimetic substitutions, we showed that S209 phosphorylation inhibits YB-1 nuclear translocation and prevents p-S102-mediated YB-1 nuclear import.

The role of dietary flavonoids for modulation of ATP binding cassette transporter mediated multidrug resistance

Flavonoids are widely existing compounds with enormous pharmacological effects from food and medicine. However, the low bioavailability in intestinal absorption and metabolism limits their clinical application. Intestinal efflux ABC (ATP binding cassette) transporters, including P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance-associated proteins (MRPs), act as "pumping doors" to regulate the efflux of flavonoids from intestinal epithelial cells into the intestinal cavity or the systemic circulation. The present review describes the critical effect of ABC transporters involved in the efflux of flavonoids which depend on its efflux direction. And the role of flavonoids for modulation of intestinal ABC transporters was emphasized and several examples were given. We summarized that the resistance effect of flavonoid-mediated multidrug on ABC transporters may influence the bioavailability of drugs, bioactive ingredients and/or toxic compounds upon dietary uptake. Meanwhile, flavonoids functionalized as reversing agents of the ABC transporter may be an important mechanism for unexpected food-drug, food-toxin or food-food interactions. The overview also indicates that elucidation of the action and mechanism of the intestinal metabolic enzymes-efflux transporters coupling will lay a foundation for improving the bioavailability of flavonoids <i>in vivo</i> and increasing their clinical efficacy.

The Identification of a Tumor Infiltration CD8+ T-Cell Gene Signature That Can Potentially Improve the Prognosis and Prediction of Immunization Responses in Papillary Renal Cell Carcinoma

Background

CD8+ T cells, vital effectors pertaining to adaptive immunity, display close relationships to the immunization responses to kill tumor cells. Understanding the effect exerted by tumor infiltration CD8+ T cells in papillary renal cell carcinoma (papRCC) is critical for assessing the prognosis process and responses to immunization therapy in cases with this disease.

Materials and Approaches

The single-cell transcriptome data of papRCC were used for screening CD8+ T-cell-correlated differentially expressed genes to achieve the following investigations. On that basis, a prognosis gene signature associated with tumor infiltration CD8+ T cell was built and verified with The Cancer Genome Atlas data set. Risk scores were determined for papRCC cases and categorized as high- or low-risk groups. The prognosis significance for risk scores was assessed with multiple-variate Cox investigation and Kaplan–Meier survival curves. In addition, the possible capability exhibited by the genetic profiles of cases to assess the response to immunization therapy was further explored.

Results

Six hundred twenty-one cell death-inhibiting RNA genes were screened using single-cell RNA sequencing. A gene signature consisting of seven genes (LYAR, YBX1, PNRC1, TCF25, MYL12B, MINOS1, and LINC01420) was then identified, and this collective was considered to be an independent prognosis indicator that could strongly assess overall survival in papRCC. In addition, the data allowed papRCC cases to fall to cohorts at high and low risks, exhibiting a wide range of clinically related features as well as different CD8+ T-cell immunization infiltration and immunization therapy responses.

Conclusions

Our work provides a possible explanation for the limited response of current immunization checkpoint-inhibiting elements for combating papRCC. Furthermore, the researchers built a novel genetic signature that was able to assess the prognosis and immunotherapeutic response of cases. This may also be considered as a promising therapeutic target for the disease.

WITHDRAWN: lncRNA Linc00173 modulates glucose metabolism and multidrug chemoresistance in SCLC: Potential molecular panel for targeted therapy

This article has been withdrawn at the request of the editor-in-chief. Following publication of this article, the editor-in-chief discovered evidence of image duplication in Figures 1I, 1J, 3F, S5B, and S6B. Given the duplication of several western blots representing several gene products, the editor-in-chief has lost faith in the findings presented in this article. The authors maintain that these image duplications were the result of errors in file management and do not affect the conclusions of the study. The full Elsevier Policy on Article Withdrawal can be found at https://www.elsevier.com/about/our-business/policies/article-withdrawal.

Potential therapeutic strategies for targeting Y-box-binding protein 1 in cancers

As one of the most conservative proteins in evolution, Y-box-binding protein 1 (YB-1) has long been considered as a potential cancer target. YB-1 is usually poorly expressed in normal cells and exerts cellular physiological functions such as DNA repair, pre-mRNA splicing and mRNA stabilizing. In cancer cells, the expression of YB-1 is up-regulated and undergoes nuclear translocation and contributes to tumorigenesis, angiogenesis, tumor proliferation, invasion, migration and chemotherapy drug resistance. During the past decades, a variety of pharmacological tools such as siRNA, shRNA, microRNA, circular RNA, lncRNA and various compounds have been developed to target YB-1 for cancer therapy. In this review, we describe the physiological characteristics of YB-1 in detail, highlight the role of YB-1 in tumors and summarize the current therapeutic methods for targeting YB-1 in cancer.

Interacting C/EBPg and YBP regulate DNA methyltransferase 1 expression in Bombyx mori embryos and ovaries

DNA methylation is an important epigenetic modification. DNA methyltransferases (Dnmts), which catalyze the formation of 5-methylcytosine, play a role in ovarian and embryonic development in some insects. However, the underlying mechanism of Dnmt in mediating ovarian and embryonic development remains unclear. In this study, the regulation and function of Bombyx mori Dnmt1 were investigated. By progressively deleting the sequence upstream of Dnmt1, a region located between -580 and -560 region from the transcription initiation site was found to have the most transcriptional activity. Electrophoretic mobility shift assay and chromatin immunoprecipitation demonstrated that transcription factor Y box binding protein (YBP), a homolog of human Y box binding protein 1 (YBX1), bound to the -580 to -560 region. YBP knockdown and overexpression in a Bombyx cell line indicated that YBP activates Dnmt1 expression. Furthermore, GST-pulldown and co-immunoprecipitation demonstrated that YBP and ovarian CCAAT/enhancer binding protein (C/EBPg) could bind each other. Simultaneous knockdown of C/EBPg and YBP was more effective than single-gene RNAi in inhibiting Dnmt1 expression and reducing the hatching rate. These results demonstrated that the interaction of C/EBPg and YBP activated Dnmt1 expression. Correlated with the expression profiles of the studies genes, our results suggest that high-level expression and interaction of C/EBPg and YBP in ovaries and embryos enhance the expression of Dnmt1, thus ensuring high reproduction rate in B. mori.

YB1 regulates miR-205/200b-ZEB1 axis by inhibiting microRNA maturation in hepatocellular carcinoma

BACKGROUND

Y-box binding protein 1 (YB1 or YBX1) plays a critical role in tumorigenesis and cancer progression. However, whether YB1 affects malignant transformation by modulating non-coding RNAs remains largely unknown. This study aimed to investigate the relationship between YB1 and microRNAs and reveal the underlying mechanism by which YB1 impacts on tumor malignancy via miRNAs-mediated regulatory network.

METHODS

The biological functions of YB1 in hepatocellular carcinoma (HCC) cells were investigated by cell proliferation, wound healing, and transwell invasion assays. The miRNAs dysregulated by YB1 were screened by microarray analysis in HCC cell lines. The regulation of YB1 on miR-205 and miR-200b was determined by quantitative real-time PCR, dual-luciferase reporter assay, RNA immunoprecipitation, and pull-down assay. The relationships of YB1, DGCR8, Dicer, TUT4, and TUT1 were identified by pull-down and coimmunoprecipitation experiments. The cellular co-localization of YB1, DGCR8, and Dicer were detected by immunofluorescent staining. The in vivo effect of YB1 on tumor metastasis was determined by injecting MHCC97H cells transduced with YB1 shRNA or shControl via the tail vein in nude BALB/c mice. The expression levels of epithelial to mesenchymal transition markers were detected by immunoblotting and immunohistochemistry assays.

RESULTS

YB1 promoted HCC cell migration and tumor metastasis by regulating miR-205/200b-ZEB1 axis partially in a Snail-independent manner. YB1 suppressed miR-205 and miR-200b maturation by interacting with the microprocessors DGCR8 and Dicer as well as TUT4 and TUT1 via the conserved cold shock domain. Subsequently, the downregulation of miR-205 and miR-200b enhanced ZEB1 expression, thus leading to increased cell migration and invasion. Furthermore, statistical analyses on gene expression data from HCC and normal liver tissues showed that YB1 expression was positively associated with ZEB1 expression and remarkably correlated with clinical prognosis.

CONCLUSION

This study reveals a previously undescribed mechanism by which YB1 promotes cancer progression by regulating the miR-205/200b-ZEB1 axis in HCC cells. Furthermore, these results highlight that YB1 may play biological functions via miRNAs-mediated gene regulation, and it can serve as a potential therapeutic target in human cancers.

Y-Box Binding Protein 1 Regulates Angiogenesis in Bladder Cancer via miR-29b-3p-VEGFA Pathway

Angiogenesis plays a vital role in the development of bladder cancer (BC). The Y-box-binding protein 1 (YB-1) is a well-known oncoprotein which is closely related to angiogenesis of tumors, but the relationship and mechanism of YB-1 and angiogenesis in BC remain unclear. Based on 56 clinical BC specimens, this study found that high expression of YB-1 samples demonstrated a higher expression of vascular endothelial growth factor A (VEGFA) than those of YB-1 low expression. Subsequently, the expression of YB-1 and miR-29b-3p was regulated in the BC cell lines where we noted that YB-1 promoted VEGFA expression by downregulating the expression of miR- 29b-3p. The ability of BC cells to induce angiogenesis decreased after YB-1 was knocked down. Moreover, the in vivo study further confirmed that YB-1 promotes angiogenesis in BC. Our findings enhance the understanding of how YB-1 promotes angiogenesis in BC and provide evidence for YB-1 as a therapeutic target of BC. Moreover, this may provide new inspiration for miRNAs replacement therapies.

Targeting the Y-box Binding Protein-1 Axis to Overcome Radiochemotherapy Resistance in Solid Tumors

Multifunctional Y-box binding protein-1 (YB-1) is highly expressed in different human solid tumors and is involved in various cellular processes. DNA damage is the major mechanism by which radiochemotherapy (RCT) induces cell death. On induction of DNA damage, a multicomponent signal transduction network, known as the DNA damage response, is activated to induce cell cycle arrest and initiate DNA repair, which protects cells against damage. YB-1 regulates nearly all cancer hallmarks described to date by participating in DNA damage response, gene transcription, mRNA splicing, translation, and tumor stemness. YB-1 lacks kinase activity, and p90 ribosomal S6 kinase and AKT are the key kinases within the RAS/mitogen-activated protein kinase and phosphoinositide 3-kinase pathways that directly activate YB-1. Thus, the molecular targeting of ribosomal S6 kinase and AKT is thought to be the most effective strategy for blocking the cellular function of YB-1 in human solid tumors. In this review, after describing the prosurvival effect of YB-1 with a focus on DNA damage repair and cancer cell stemness, clinical evidence will be provided indicating an inverse correlation between YB-1 expression and the treatment outcome of solid tumors after RCT. In the interest of being concise, YB-1 signaling cascades will be briefly discussed and the current literature on YB-1 posttranslational modifications will be summarized. Finally, the current status of targeting the YB-1 axis, especially in combination with RCT, will be highlighted.

7-Hydorxyindirubin is capable of specifically inhibiting anticancer drug-induced YB-1 nuclear translocation without showing cytotoxicity in HepG2 hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is one of the most common human malignant tumors. It is known that in the cells of many cancers, including HCC, nuclear translocation and accumulation of YB-1 often indicates a poor prognosis. This nuclear translocation is induced by genotoxic stress resulting from administration of anticancer agents. Accumulation of YB-1 in the nucleus induces the expression of many genes related to cancer aggressiveness. Therefore, compounds capable of inhibiting anticancer drug-induced YB-1 nuclear translocation without cytotoxicity will be a powerful tool for cancer chemotherapy. In the present study, we found that indirubin derivative, 7-hydroxyindirubin strongly inhibited the actinomycin D-induced nuclear translocation of YB-1 more efficiently without showing cytotoxicity in HepG2, a human HCC cells. The compound successfully suppressed the nuclear YB-1-mediated expression of genes such as MDR1, MVP, EGFR, and CXCR4, which are known to disturb cancer treatment. 7-Hydroxyindirubin also increased the susceptibility of drug-resistant HepG2 cells to ActD. It was also demonstrated that 7-hydroxyindirubin inhibits the nuclear translocation of YB-1 with or without phosphorylation at the Ser102 residue.

FOLFOX Therapy Induces Feedback Upregulation of CD44v6 through YB-1 to Maintain Stemness in Colon Initiating Cells

Cancer initiating cells (CICs) drive tumor formation and drug-resistance, but how they develop drug-resistance characteristics is not well understood. In this study, we demonstrate that chemotherapeutic agent FOLFOX, commonly used for drug-resistant/metastatic colorectal cancer (CRC) treatment, induces overexpression of CD44v6, MDR1, and oncogenic transcription/translation factor Y-box-binding protein-1 (YB-1). Our study revealed that CD44v6, a receptor for hyaluronan, increased the YB-1 expression through PGE2/EP1-mTOR pathway. Deleting CD44v6, and YB-1 by the CRISPR/Cas9 system attenuates the in vitro and in vivo tumor growth of CICs from FOLFOX resistant cells. The results of DNA:CD44v6 immunoprecipitated complexes by ChIP (chromatin-immunoprecipitation) assay showed that CD44v6 maintained the stemness traits by promoting several antiapoptotic and stemness genes, including cyclin-D1,BCL2,FZD1,GINS-1, and MMP9. Further, computer-based analysis of the clones obtained from the DNA:CD44v6 complex revealed the presence of various consensus binding sites for core stemness-associated transcription factors “CTOS” (c-Myc, TWIST1, OCT4, and SOX2). Simultaneous expressions of CD44v6 and CTOS in CD44v6 knockout CICs reverted differentiated CD44v6-knockout CICs into CICs. Finally, this study for the first time describes a positive feedback loop that couples YB-1 induction and CD44 alternative splicing to sustain the MDR1 and CD44v6 expressions, and CD44v6 is required for the reversion of differentiated tumor cells into CICs.

RNA packaging into extracellular vesicles: An orchestra of RNA-binding proteins?

Extracellular vesicles (EVs) are heterogeneous membranous particles released from the cells through different biogenetic and secretory mechanisms. We now conceive EVs as shuttles mediating cellular communication, carrying a variety of molecules resulting from intracellular homeostatic mechanisms. The RNA is a widely detected cargo and, impressively, a recognized functional intermediate that elects EVs as modulators of cancer cell phenotypes, determinants of disease spreading, cell surrogates in regenerative medicine, and a source for non-invasive molecular diagnostics. The mechanistic elucidation of the intracellular events responsible for the engagement of RNA into EVs will significantly improve the comprehension and possibly the prediction of EV "quality" in association with cell physiology. Interestingly, the application of multidisciplinary approaches, including biochemical as well as cell-based and computational strategies, is increasingly revealing an active RNA-packaging process implicating RNA-binding proteins (RBPs) in the sorting of coding and non-coding RNAs. In this review, we provide a comprehensive view of RBPs recently emerging as part of the EV biology, considering the scenarios where: (i) individual RBPs were detected in EVs along with their RNA substrates, (ii) RBPs were detected in EVs with inferred RNA targets, and (iii) EV-transcripts were found to harbour sequence motifs mirroring the activity of RBPs. Proteins so far identified are members of the hnRNP family (hnRNPA2B1, hnRNPC1, hnRNPG, hnRNPH1, hnRNPK, and hnRNPQ), as well as YBX1, HuR, AGO2, IGF2BP1, MEX3C, ANXA2, ALIX, NCL, FUS, TDP-43, MVP, LIN28, SRP9/14, QKI, and TERT. We describe the RBPs based on protein domain features, current knowledge on the association with human diseases, recognition of RNA consensus motifs, and the need to clarify the functional significance in different cellular contexts. We also summarize data on previously identified RBP inhibitor small molecules that could also be introduced in EV research as potential modulators of vesicular RNA sorting.

LINC00857 Interacting with YBX1 to Regulate Apoptosis and Autophagy via MET and Phosphor-AMPKa Signaling

Long noncoding RNA (lncRNA) LINC00857 has been reported to be upregulated in lung cancer and related to poor patient survival. It can regulate cell proliferation and tumor growth in lung cancer as well as several other cancers. However, the underlying molecular mechanisms that are regulated by LINC00857 are unclear. In this study, we found that LINC00857 silencing can impair cell proliferation in 14 different genomic alterations of lung cancer cell lines. These alterations are EGFR, KRAS, TP53, MET, and LKB1 mutations. The cell apoptosis and autophagy were induced upon LINC00857 silencing in lung cancer cells. Mechanistically, LINC00857 can bind to the Y-box binding protein 1 (YBX1) protein, prevent it from proteasomal degradation, and increase its nuclear translocation. LINC00857 regulated MET expression via YBX1 at a transcriptional level. Induced cell autophagy by LINC00857 knockdown was mainly through increased phosphor-AMP-activated protein kinase (p-AMPK)a. Collectively, LINC00857-YBX1-MET/p-AMPKa signaling is critical to regulate cell proliferation, apoptosis, and autophagy, which may provide a potential clinically therapeutic target in lung cancer.

Blocking Y-Box Binding Protein-1 through Simultaneous Targeting of PI3K and MAPK in Triple Negative Breast Cancers

Simple Summary

Triple-negative breast cancer (TNBC) is associated with the high rates of relapse and metastasis and poor survival. YB-1 is overexpressed in TNBC tumor tissues. In the present study, we demonstrated that S102 phosphorylation of YB-1 in TNBC cell lines depend on the mutation status of the components of the MAPK/ERK and PI3K/Akt pathways. Simultaneous targeting of MEK and PI3K was found to be the most effective approach to block YB-1 phosphorylation and to inhibit YB-1 dependent cell proliferation. YBX1 knockout was sufficient to block TNBC tumor growth.

Abstract

The multifunctional protein Y-box binding protein-1 (YB-1) regulates all the so far described cancer hallmarks including cell proliferation and survival. The MAPK/ERK and PI3K/Akt pathways are also the major pathways involved in cell growth, proliferation, and survival, and are the frequently hyperactivated pathways in human cancers. A gain of function mutation in KRAS mainly leads to the constitutive activation of the MAPK pathway, while the activation of the PI3K/Akt pathway occurs either through the loss of PTEN or a gain of function mutation of the catalytic subunit alpha of PI3K (PIK3CA). In this study, we investigated the underlying signaling pathway involved in YB-1 phosphorylation at serine 102 (S102) in KRAS(G13D)-mutated triple-negative breast cancer (TNBC) MDA-MB-231 cells versus PIK3CA(H1047R)/PTEN(E307K) mutated TNBC MDA-MB-453 cells. Our data demonstrate that S102 phosphorylation of YB-1 in KRAS-mutated cells is mainly dependent on the MAPK/ERK pathway, while in PIK3CA/PTEN-mutated cells, YB-1 S102 phosphorylation is entirely dependent on the PI3K/Akt pathway. Independent of the individual dominant pathway regulating YB-1 phosphorylation, dual targeting of MEK and PI3K efficiently inhibited YB-1 phosphorylation and blocked cell proliferation. This represents functional crosstalk between the two pathways. Our data obtained from the experiments, applying pharmacological inhibitors and genetic approaches, shows that YB-1 is a key player in cell proliferation, clonogenic activity, and tumor growth of TNBC cells through the MAPK and PI3K pathways. Therefore, dual inhibition of these two pathways or single targeting of YB-1 may be an effective strategy to treat TNBC.

YB-1 Interferes with TNFα-TNFR Binding and Modulates Progranulin-Mediated Inhibition of TNFα Signaling

Inflammation and an influx of macrophages are common elements in many diseases. Among pro-inflammatory cytokines, tumor necrosis factor α (TNFα) plays a central role by amplifying the cytokine network. Progranulin (PGRN) is a growth factor that binds to TNF receptors and interferes with TNFα-mediated signaling. Extracellular PGRN is processed into granulins by proteases released from immune cells. PGRN exerts anti-inflammatory effects, whereas granulins are pro-inflammatory. The factors coordinating these ambivalent functions remain unclear. In our study, we identify Y-box binding protein-1 (YB-1) as a candidate for this immune-modulating activity. Using a yeast-2-hybrid assay with YB-1 protein as bait, clones encoding for progranulin were selected using stringent criteria for strong interaction. We demonstrate that at physiological concentrations, YB-1 interferes with the binding of TNFα to its receptors in a dose-dependent manner using a flow cytometry-based binding assay. We show that YB-1 in combination with progranulin interferes with TNFα-mediated signaling, supporting the functionality with an NF-κB luciferase reporter assay. Together, we show that YB-1 displays immunomodulating functions by affecting the binding of TNFα to its receptors and influencing TNFα-mediated signaling via its interaction with progranulin.

Regulation of Poly(ADP-Ribose) Polymerase 1 Activity by Y-Box-Binding Protein 1

Y-box-binding protein 1 (YB-1) is a multifunctional positively charged protein that interacts with DNA or RNA and poly(ADP-ribose) (PAR). YB-1 is poly(ADP-ribosyl)ated and stimulates poly(ADP-ribose) polymerase 1 (PARP1) activity. Here, we studied the mechanism of YB-1-dependent PAR synthesis by PARP1 in vitro using biochemical and atomic force microscopy assays. PAR synthesis activity of PARP1 is known to be facilitated by co-factors such as Mg2+. However, in contrast to an Mg2+-dependent reaction, the activation of PARP1 by YB-1 is accompanied by overall up-regulation of protein PARylation and shortening of the PAR polymer. Therefore, YB-1 and cation co-factors stimulated PAR synthesis in divergent ways. PARP1 autoPARylation in the presence of YB-1 as well as trans-PARylation of YB-1 are greatly affected by the type of damaged DNA, suggesting that PARP1 activation depends on the formation of a PARP1-YB-1-DNA ternary complex. An unstructured C-terminal part of YB-1 involved in an interaction with PAR behaves similarly to full-length YB-1, indicating that both DNA and PAR binding are involved in the stimulation of PARP1 activity by YB-1. Thus, YB-1 is likely linked to the regulation of PARylation events in cells via an interaction with PAR and damaged DNA.

Simultaneous Targeting of RSK and AKT Efficiently Inhibits YB-1-Mediated Repair of Ionizing Radiation-Induced DNA Double-Strand Breaks in Breast Cancer Cells

PURPOSE

Y-box binding protein 1 (YB-1) overexpression is associated with chemotherapy- and radiation therapy resistance. Ionizing radiation (IR), receptor tyrosine kinase ligands, and mutation in KRAS gene stimulate activation of YB-1. YB-1 accelerates the repair of IR-induced DNA double-strand breaks (DSBs). Ribosomal S6 kinase (RSK) is the main kinase inducing YB-1 phosphorylation. We investigated the impact of RSK targeting on DSB repair and radiosensitivity.

MATERIALS AND METHODS

The triple negative breast cancer (TNBC) cell lines MDA-MB-231, MDA-MB-468, and Hs 578T, in addition to non-TNBC cell lines MCF7, HBL-100, and SKBR3, were used. MCF-10A cells were included as normal breast epithelial cells. The RSK inhibitor LJI308 was used to investigate the role of RSK activity in S102 phosphorylation of YB-1 and YB-1-associated signaling pathways. The activation status of the underlying pathways was investigated by Western blotting after treatment with pharmacologic inhibitors or transfection with siRNA. The impact of LJI308 on DSB repair and postirradiation cell survival was tested by the γH2AX foci and the standard clonogenic assays, respectively.

RESULTS

LJI308 inhibited the phosphorylation of RSK (T359/S363) and YB-1 (S102) after irradiation, treatment with EGF, and in cells expressing a KRAS mutation. LJI308 treatment slightly inhibited DSB repair only in some of the cell lines tested. This was shown to be due to PI3K-dependent stimulation of AKT or constitutive AKT activity mainly in cancer cells but not in normal breast epithelial MCF-10A cells. Simultaneous targeting of AKT and RSK strongly blocked DSB repair in all cancer cell lines, independent of TNBC status or KRAS mutation, with a minor effect in MCF-10A cells. Cotargeting of RSK- and AKT-induced radiation sensitivity in TNBC MDA-MB-231 and non-TNBC MCF7 cells but not in MCF-10A cells.

CONCLUSIONS

Simultaneous targeting of RSK and AKT might be an efficient approach to block the repair of DSBs after irradiation and to induce radiosensitization of breast cancer cells.

Y-Box Binding Protein 1 Expression in Trophoblast Cells Promotes Fetal and Placental Development

Y-box binding protein 1 (YB-1) is pivotal for the regulation of cancerogenesis and inflammation. However, its involvement in pregnancy processes such as fetal and placental development remains to be elucidated. We studied Ybx1 (YB-1)^+/− heterozygous intercrossings and compared them to YB-1^+/+ wild-type (WT) combinations. Additionally, we generated trophoblast-specific YB-1-deficient mice by pairing FVB Cyp19-Cre females to YB-1^fl/fl males. YB-1^fl/fl-paired FVB WT females served as controls. Serial in vivo ultrasound measurements were performed to assess fetal and placental parameters. After sacrificing the females, implantation and abortion rates were recorded, spiral artery (SA) remodeling was analyzed and fetal and placental weights were determined. Compared to YB-1^+/+ counterparts, YB-1^+/− females showed reduced implantation areas at gestation day (GD)10, insufficiently remodeled SAs at GD12, increased placental diameter/thickness ratios at GD14 and reduced placental and fetal weights at GD14. Compared to WT, Cyp19-Cre females with YB-1-deficient placentas showed reduced implantation areas at GD8, 10 and 12; decreased placental areas and diameters at GD10 and 12; diminished placental thicknesses at GD12; as well as reduced placental weights at GD12 and 14. In conclusion, our data suggest haploinsufficiency of YB-1 resulting in disturbed fetal and placental development. Moreover, we provide the first evidence for the relevance of trophoblast-specific YB-1 for placentation.

Tumour Progression Stage-Dependent Secretion of YB-1 Stimulates Melanoma Cell Migration and Invasion

Secreted factors play an important role in intercellular communication. Therefore, they are not only indispensable for the regulation of various physiological processes but can also decisively advance the development and progression of tumours. In the context of inflammatory disease, Y-box binding protein 1 (YB-1) is actively secreted and the extracellular protein promotes cell proliferation and migration. In malignant melanoma, intracellular YB-1 expression increases during melanoma progression and represents an unfavourable prognostic marker. Here, we show active secretion of YB-1 from melanoma cells as opposed to benign cells of the skin. Intriguingly, YB-1 secretion correlates with the stage of melanoma progression and depends on a calcium- and ATP-dependent non-classical secretory pathway leading to the occurrence of YB-1 in the extracellular space as a free protein. Along with an elevated YB-1 secretion of melanoma cells in the metastatic growth phase, extracellular YB-1 exerts a stimulating effect on melanoma cell migration, invasion, and tumourigenicity. Collectively, these data suggest that secreted YB-1 plays a functional role in melanoma cell biology, stimulating metastasis, and may serve as a novel biomarker in malignant melanoma that reflects tumour aggressiveness.

YB-1: The key to personalised prostate cancer management?

Y-box-binding protein 1 (YB-1) is a DNA/RNA binding protein increasingly implicated in the regulation of cancer cell biology. Normally located in the cytoplasm, nuclear localisation in prostate cancer is associated with more aggressive, potentially treatment-resistant disease. This is attributed to the ability of YB-1 to act as a transcription factor for various target genes associated with androgen receptor signalling, survival, DNA repair, proliferation, invasion, differentiation, angiogenesis and hypoxia. This review aims to examine the clinical potential of YB-1 in the detection and therapeutic management of prostate cancer.

A Novel Ten-Gene Signature Predicting Prognosis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) has a dismal long-term outcome. We aimed to construct a multi-gene model for prognosis prediction to inform HCC management. The cancer-specific differentially expressed genes (DEGs) were identified using RNA-seq data of paired tumor and normal tissue. A prognostic signature was built by LASSO regression analysis. Gene set enrichment analysis (GSEA) was performed to further understand the underlying molecular mechanisms. A 10-gene signature was constructed to stratify the TCGA and ICGC cohorts into high- and low-risk groups where prognosis was significantly worse in the high-risk group across cohorts (P < 0.001 for all). The 10-gene signature outperformed all previously reported models for both C-index and the AUCs for 1-, 3-, 5-year survival prediction (C-index, 0.84 vs 0.67 to 0.73; AUCs for 1-, 3- and 5-year OS, 0.84 vs 0.68 to 0.79, 0.81 to 0.68 to 0.80, and 0.85 vs 0.67 to 0.78, respectively). Multivariate Cox regression analysis revealed risk group and tumor stage to be independent predictors of survival in HCC. A nomogram incorporating tumor stage and signature-based risk group showed better performance for 1- and 3-year survival than for 5-year survival. GSEA revealed enrichment of pathways related to cell cycle regulation among high-risk samples and metabolic processes in the low-risk group. Our 10-gene model is robust for prognosis prediction and may help inform clinical management of HCC.

Long non-coding RNAs in gastric cancer: New emerging biological functions and therapeutic implications

Gastric cancer (GC) is currently the fourth most common malignancy and the third leading cause of cancer-related deaths worldwide. Long non-coding RNAs (lncRNAs), transcriptional products with more than 200 nucleotides, are not as well-characterized as protein-coding RNAs. Accumulating evidence has recently revealed that maladjustments of diverse lncRNAs may play key roles in multiple genetic and epigenetic phenomena in GC, affecting all aspects of cellular homeostasis, such as proliferation, migration, and stemness. However, the full extent of their functionality remains to be clarified. Considering the lack of viable biomarkers and therapeutic targets, future research should be focused on unravelling the intricate relationships between lncRNAs and GC that can be translated from bench to clinic. Here, we summarized the state-of-the-art advances in lncRNAs and their biological functions in GC, and we further discuss their potential diagnostic and therapeutic roles. We aim to shed light on the interrelationships between lncRNAs and GC with respect to their potential therapeutic applications. With better understanding of these relationships, the biological functions of lncRNAs in GC development will be exploitable, and promising new strategies developed for the prevention and treatment of GC.

MicroRNA-379-5p/YBX1 Axis Regulates Cellular EMT to Suppress Migration and Invasion of Nasopharyngeal Carcinoma Cells

Background

Epithelial–mesenchymal transition (EMT) is a major actor modulating the metastasis of nasopharyngeal carcinoma (NPC). Increasing evidence indicates that microRNAs (miRs) are the important regulators of EMT program. However, the potential roles and underlying mechanisms of miR‑379-5p in regulating EMT of NPC cells remain unclear.

Methods

miR-379-5p expression levels in human NPC tissues and cell lines were detected via quantitative real-time PCR (qRT-PCR). Then, the correlations between miR-379-5p expression in NPC tissues and clinicopathologic features and patients’ prognosis were analyzed. The effect of miR-379-5p on the expression of EMT markers in NPC cells was evaluated by Western blot and qRT-PCR. NPC cells’ migration and invasion were evaluated in vitro by Transwell migration and invasion assays, respectively. The target of miR-379-5p was predicted with three publicly available databases and further validated with dual-luciferase reporter assay, qRT-PCR, and Western blot.

Results

The expression of miR-379-5p was significantly decreased in NPC tissues, and its low expression was significantly associated with multiple unfavorable clinicopathological factors and poor prognosis of NPC patients. Meanwhile, miR-379-5p was downregulated in NPC cell lines, and its exotic expression inhibited EMT to reduce the migration and invasion of NPC cells. Furthermore, Y-box binding protein 1 (YBX1) was identified and validated as a direct target of miR-379-5p, and restoring YBX1 expression could reverse the inhibitive effect of miR-379-5p on NPC cell EMT, migration and invasion.

Conclusion

Taken together, our findings indicate that miR-379-5p inhibits the EMT of NPC cells to reduce their migration and invasion abilities by post-transcriptionally suppressing YBX1 expression, providing a novel potential treatment target for NPC patients.

Overexpression of YBX1 Promotes Pancreatic Ductal Adenocarcinoma Growth via the GSK3B/Cyclin D1/Cyclin E1 Pathway

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal cancers due to frequently late diagnosis and futile treatment. It is a crucial necessity to determine the mechanisms of PDAC. Y-box Binding Protein 1 (YBX1), a highly conserved transcription factor, has been previously reported to play a role in various hallmarks of cancer. We show here that YBX1 is significantly overexpressed in PDAC and correlates with poor prognosis and reduced survival. In PDAC cell lines, YBX1 regulated cell-cycle progression, proliferation, and the expression of glycogen synthase kinase 3 beta (GSK3B) and cell-cycle-related proteins cyclin D1 and E1. Dual-luciferase reporter and chromatin immunoprecipitation (ChIP) assays established that YBX1 binds to the promoter of GSK3B, suggesting that YBX1 promotes pancreatic cancer cell growth through induction of GSK3B expression. These findings offer important insights into the mechanisms underlying pathologic proliferation in PDAC.

Effect and mechanism of YB-1 knockdown on glioma cell growth, migration, and apoptosis

Y-box binding protein 1 (YB-1) is manifested as its involvement in cell proliferation and differentiation and malignant cell transformation. Overexpression of YB-1 is associated with glioma progression and patient survival. The aim of this study is to investigate the influence of YB-1 knockdown on glioma cell progression and reveal the mechanisms of YB-1 knockdown on glioma cell growth, migration, and apoptosis. It was found that the knockdown of YB-1 decreased the mRNA and protein levels of YB-1 in U251 glioma cells. The knockdown of YB-1 significantly inhibited cell proliferation, colony formation, and migration in vitro and tumor growth in vivo. Proteome and phosphoproteome data revealed that YB-1 is involved in glioma progression through regulating the expression and phosphorylation of major proteins involved in cell cycle, adhesion, and apoptosis. The main regulated proteins included CCNB1, CCNDBP1, CDK2, CDK3, ADGRG1, CDH-2, MMP14, AIFM1, HO-1, and BAX. Furthermore, it was also found that YB-1 knockdown is associated with the hypo-phosphorylation of ErbB, mTOR, HIF-1, cGMP-PKG, and insulin signaling pathways, and proteoglycans in cancer. Our findings indicated that YB-1 plays a key role in glioma progression in multiple ways, including regulating the expression and phosphorylation of major proteins associated with cell cycle, adhesion, and apoptosis.

Inhibition of Transcription Induces Phosphorylation of YB-1 at Ser102 and Its Accumulation in the Nucleus

The Y-box binding protein 1 (YB-1) is an RNA/DNA-binding protein regulating gene expression in the cytoplasm and the nucleus. Although mostly cytoplasmic, YB-1 accumulates in the nucleus under stress conditions. Its nuclear localization is associated with aggressiveness and multidrug resistance of cancer cells, which makes the understanding of the regulatory mechanisms of YB-1 subcellular distribution essential. Here, we report that inhibition of RNA polymerase II (RNAPII) activity results in the nuclear accumulation of YB-1 accompanied by its phosphorylation at Ser102. The inhibition of kinase activity reduces YB-1 phosphorylation and its accumulation in the nucleus. The presence of RNA in the nucleus is shown to be required for the nuclear retention of YB-1. Thus, the subcellular localization of YB-1 depends on its post-translational modifications (PTMs) and intracellular RNA distribution.

Targeting Phosphorylation of Y-Box-Binding Protein YBX1 by TAS0612 and Everolimus in Overcoming Antiestrogen Resistance

Nuclear expression of Y-box-binding protein (YBX1) is closely correlated with clinical poor outcomes and drug resistance in breast cancer. Nuclear translocation of YBX1 is facilitated by YBX1 phosphorylation at serine 102 by AKT, p70S6K, and p90RSK, and the phosphorylated YBX1 (pYBX1) promotes expression of genes related to drug resistance and cell growth. A forthcoming problem to be addressed is whether targeting the phosphorylation of YBX1 overcomes antiestrogen resistance by progressive breast cancer. Here, we found that increased expression of pYBX1 was accompanied by acquired resistance to antiestrogens, fulvestrant and tamoxifen. Forced expression of YBX1/S102E, a constitutive phosphorylated form, resulted in acquired resistance to fulvestrant. Inversely, YBX1 silencing specifically overcame antiestrogen resistance. Furthermore, treatment with everolimus, an mTORC1 inhibitor, or TAS0612, a novel multikinase inhibitor of AKT, p70S6K, and p90RSK, suppressed YBX1 phosphorylation and overcame antiestrogen resistance in vitro and in vivo IHC analysis revealed that expression of pYBX1 and YBX1 was augmented in patients who experienced recurrence during treatment with adjuvant endocrine therapies. Furthermore, pYBX1 was highly expressed in patients with triple-negative breast cancer compared with other subtypes. TAS0612 also demonstrated antitumor effect against triple-negative breast cancer in vivo Taken together, our findings suggest that pYBX1 represents a potential therapeutic target for treatment of antiestrogen-resistant and progressive breast cancer.

Multiplex profiling identifies clinically relevant signalling proteins in an isogenic prostate cancer model of radioresistance

The exact biological mechanism governing the radioresistant phenotype of prostate tumours at a high risk of recurrence despite the delivery of advanced radiotherapy protocols remains unclear. This study analysed the protein expression profiles of a previously generated isogenic 22Rv1 prostate cancer model of radioresistance using DigiWest multiplex protein profiling for a selection of 90 signalling proteins. Comparative analysis of the profiles identified a substantial change in the expression of 43 proteins. Differential PARP-1, AR, p53, Notch-3 and YB-1 protein levels were independently validated using Western Blotting. Pharmacological targeting of these proteins was associated with a mild but significant radiosensitisation effect at 4Gy. This study supports the clinical relevance of isogenic in vitro models of radioresistance and clarifies the molecular radiation response of prostate cancer cells.

Why Be One Protein When You Can Affect Many? The Multiple Roles of YB-1 in Lung Cancer and Mesothelioma

Lung cancers and malignant pleural mesothelioma (MPM) have some of the worst 5-year survival rates of all cancer types, primarily due to a lack of effective treatment options for most patients. Targeted therapies have shown some promise in thoracic cancers, although efficacy is limited only to patients harboring specific mutations or target expression. Although a number of actionable mutations have now been identified, a large population of thoracic cancer patients have no therapeutic options outside of first-line chemotherapy. It is therefore crucial to identify alternative targets that might lead to the development of new ways of treating patients diagnosed with these diseases. The multifunctional oncoprotein Y-box binding protein-1 (YB-1) could serve as one such target. Recent studies also link this protein to many inherent behaviors of thoracic cancer cells such as proliferation, invasion, metastasis and involvement in cancer stem-like cells. Here, we review the regulation of YB-1 at the transcriptional, translational, post-translational and sub-cellular levels in thoracic cancer and discuss its potential use as a biomarker and therapeutic target.

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.