NOLC1, an enhancer of nasopharyngeal carcinoma progression, is essential for TP53 to regulate MDM2 expression

CircRNA-NOLC1 mediates Insulin-like growth factor 1 receptor via performing as a ceRNA of miRNA-140-5p to facilitate testicular germ cell tumor advancement

OBJECTIVE

The study explored the molecular mechanism of circNOLC1 influencing Testicular Germ Cell Tumor (TGCT) progression.

METHODS

The study used TGCT tissue samples and cell lines for investigations. The circNOLC1 and miR-140-5p expression in TGCT tissues were done through RT-qPCR. Analysis of the association of circNOLC1 with TGCT clinic-pathological features was also done. Transfections of circNOLC1, miR-140-5p or Insulin-like GrowthFfactor 1 Receptor (IGF1R)-related sequences or plasmids into TCAM-2 and NCCIT TGCT cells were done. The circNOLC1, miR-140-5p, and IGF1R mRNA expression in cells were done through RT-qPCR. Interaction between miR-140-5p, circNOLC1, and IGF1R was examined using a dual-luciferase reporter assay. MTT assay and colony-forming assay were used to investigate cell proliferation. Apoptosis was determined by flow cytometry. Transwell assay was used to investigate cell invasion. IGF1R protein expression was determined through a western blot.

RESULTS

Increased circNOLC1 in TGCT tissues was correlated with lymph node metastasis, clinical stage, and pathological grade of TGCT patients. CircNOLC1 knock-down inhibited TGCT cell proliferation, colony formation, and invasion, and promotedapoptosis. MiR-140-5p was reduced while IGF1R was upregulated in TGCT tissues and cell lines. Moreover, miR-140-5p mimic could reverse the effect of circNOLC1 knock-down on malignant behaviors of TGCT cells. The authors demonstrated that elevated IGF1R reversed the negative effect of miR-140-5p mimic on TGCT cell proliferation, colony formation, and invasion. CircNOLC1 can act as a sponge of miR-140-5p to up-regulate the IGF1R expression level.

CONCLUSION

The study highlights that circNOLC1 promotes the progression of TGCT by regulating the miR-140-5p/IGF1R axis.

SPOP/NOLC1/B4GALT1 signaling axis enhances paclitaxel resistance in endometrial cancer by inducing O-dysglycosylation

The effective treatment of paclitaxel-resistant patients remains a major challenge. We found that nucleolar and coiled body phosphoprotein 1 (NOLC1) was highly expressed in the paclitaxel-resistant endometrial cancer (ECa) cells and pathological tissue of ECa patients, which could promote the occurrence and progression of ECa cells. Mechanistically, we confirmed that the E3 ubiquitin ligase substrate-binding adaptor SPOP mediates the ubiquitination and degradation of NOLC1, thereby maintaining normal protein levels. However, ECa-associated SPOP mutants abrogated the binding and ubiquitination of NOLC1, resulting in the accumulation of NOLC1, and ultimately promoting the proliferation, migration, and invasion of ECa cells. In addition, we demonstrated that NOLC1 could act as a transcriptional factor to activate the transcriptional expression of B4GALT1, ultimately leading to abnormal glycosylation metabolism. Moreover, knockdown of B4GALT1 can partly counteract the cancer-promoting effect caused by the overexpression of NOLC1 in vitro and in vivo. Based on these findings, an O-glycosylation inhibitor combined with paclitaxel could effectively improve the sensitivity of paclitaxel-resistant cells. In summary, we found that SPOP can negatively regulate the NOLC1-B4GALT1 signaling axis in ECa, whereas ECa-associated SPOP mutants lead to abnormal activation of this signaling axis, leading to glycosylation metabolism disorders. In addition, paclitaxel combined with B4GALT1-KD or glycosylation inhibitors can significantly inhibit the growth of paclitaxel-resistant endometrial cancer cells.

Antisense oligonucleotide-mediated TRA2β poison exon inclusion induces the expression of a lncRNA with anti-tumor effects

Upregulated expression of the oncogenic splicing factor TRA2β occurs in human tumors partly through decreased inclusion of its autoregulatory non-coding poison exon (PE). Here, we reveal that low TRA2β-PE inclusion negatively impacts patient survival across several tumor types. We demonstrate the ability of splice-switching antisense oligonucleotides (ASOs) to promote TRA2β-PE inclusion and lower TRA2β protein levels in pre-clinical cancer models. TRA2β-PE-targeting ASOs induce anti-cancer phenotypes and widespread transcriptomic alterations with functional impact on RNA processing, mTOR, and p53 signaling pathways. Surprisingly, the effect of TRA2β-PE-targeting ASOs on cell viability are not phenocopied by TRA2β knockdown. Mechanistically, we find that the ASO functions by both decreasing TRA2β protein and inducing the expression of TRA2β-PE-containing transcripts that act as long non-coding RNAs to sequester nuclear proteins. Finally, TRA2β-PE-targeting ASOs are toxic to preclinical 3D organoid and in vivo patient-derived xenograft models. Together, we demonstrate that TRA2β-PE acts both as a regulator of protein expression and a long-noncoding RNA to control cancer cell growth. Drugging oncogenic splicing factors using PE-targeting ASOs is a promising therapeutic strategy.

FOXA1 activates NOLC1 transcription through NOTCH pathway to promote cell stemness in lung adenocarcinoma

Tumor cell stemness plays a pivotal role in generating functional heterogeneity within tumors and is implicated in essential processes such as drug resistance, metastasis, and cell proliferation. Therefore, creating novel tumor diagnostic techniques and therapeutic plans requires a knowledge of the possible processes that preserve the stem cell-like qualities of cancers. Bioinformatics analysis of NOLC1 expression in lung adenocarcinoma (LUAD) and prediction of its upstream transcription factors and their binding sites were completed. RT-qPCR detection of NOLC1 and FOXA1 expression, colony formation assay of cell proliferation, Transwell assay of cell invasion, sphere formation assay of cell stemness, western blot detection of CD133, OCT4, GLI1, NOTCH1 and Hes1 expression, CCK-8 assay of IC50 value of cisplatin, and ChIP and dual-luciferase reporter validation of binding relationship between NOLC1 and FOXA1 were done. NOLC1 expression was elevated in LUAD cells and tissues. Decreased NOLC1 expression inhibited the proliferation and invasive capacity of LUAD cells, prevented LUAD cells from becoming stem cells, and suppressed cisplatin resistance in the cells. Rescue tests demonstrated that NOLC1 activated the NOTCH pathway to increase the stemness of LUAD cells and promoted cisplatin resistance in LUAD cells. The activation of NOLC1 transcription by FOXA1 was validated by bioinformatics prediction and molecular verification, and the FOXA1/NOLC1 axis enhanced the stemness of LUAD cells. Activation of NOLC1 transcription by FOXA1 through NOTCH pathway promoted stemness of LUAD. FOXA1/NOLC1 axis is expected to become a new target for inhibiting stemness of LUAD cells.

NOLC1 was identified as a tumor suppressor gene in thyroid cancer and correlated with prognosis by bioinformatics

Thyroid cancer (THCA) is the most common endocrine malignancy, mainly affecting women's unilateral glandular lobes. However, for relapsed and distant metastasis of THCA patients, the existing early diagnosis and treatment methods were still insufficient, and a new method was urgently needed to diagnose and treat them. Nucleolar and coiled-body phosphoprotein 1 (NOLC1) was one of the most phosphorylated proteins in the cell, which was located mainly in the nucleolus. In addition, more and more studies have confirmed that NOLC1 plays a crucial role in various pathological processes, such as the occurrence and progression of cancer and viral infection. A previous study showed that NOLC1, as a member of RNA-binding protein, was significantly correlated with the prognosis of THCA patients. However, further exploration of NOLC1 in THCA is limited. To further explore the role of NOLC1 in THCA, we conducted expression and survival prognosis analysis of NOLC1 using multiple databases. We also evaluated the correlation between NOLC1 gene expression and clinical characteristics of THCA patients. Furthermore, we analyzed the relationship between NOLC1 and other genes, followed by enrichment analysis to investigate its metabolic pathways and molecular metabolism processes. Additionally, we examined the association between immune cell infiltration in tumor microenvironment and NOLC1. Notably, through vitro experiments, we confirmed the tumor suppressive effect of NOLC1 on the proliferation and migration of human THCA cells, providing evidence for clinical diagnosis of THCA. Furthermore, we confirmed the tumor suppressive effect of NOLC1 in vivo xenograft assay. To sum up, our results suggest that NOLC1 is a tumor suppressor gene for THCA.

E3 ubiquitin ligases in nasopharyngeal carcinoma and implications for therapies

Nasopharyngeal carcinoma (NPC) is one of the most common squamous cell carcinomas of the head and neck, and Epstein-Barr virus (EBV) infection is one of the pathogenic factors involved in the oncogenetic development and progression of NPC. E3 ligases, which are key members of the ubiquitin proteasome system (UPS), specifically recognize various oncogenic factors and tumor suppressors and contribute to determining their fate through ubiquitination. Several studies have demonstrated that E3 ligases are aberrantly expressed and mutated in NPC and that these changes are closely associated with the occurrence and progression of NPC. Herein, we aim to thoroughly review the specific action mechanisms by which E3 ligases participate in NPC signaling pathways and discuss their functional relationship with EBV. Moreover, we describe the current progress in and limitations for targeted therapies against E3 ligases in NPC. KEY MESSAGES: • E3 ubiquitin ligases, as members of the UPS system, determine the fate of their substrates and may act either as oncogenic or anti-tumorigenic factors in NPC. • Mutations or dysregulated expression of E3 ubiquitin ligases is closely related to the occurrence, development, and therapeutic sensitivity of NPC, as they play important roles in several signaling pathways affected by EBV infection. • As promising therapeutic targets, E3 ligases may open new avenues for treatment and for improving the prognosis of NPC patients.

Roles of NOLC1 in cancers and viral infection

BACKGROUND

The nucleolus is considered the center of metabolic control and an important organelle for the biogenesis of ribosomal RNA (rRNA). Nucleolar and coiled-body phosphoprotein 1(NOLC1), which was originally identified as a nuclear localization signal-binding protein is a nucleolar protein responsible for nucleolus construction and rRNA synthesis, as well as chaperone shuttling between the nucleolus and cytoplasm. NOLC1 plays an important role in a variety of cellular life activities, including ribosome biosynthesis, DNA replication, transcription regulation, RNA processing, cell cycle regulation, apoptosis, and cell regeneration.

PURPOSE

In this review, we introduce the structure and function of NOLC1. Then we elaborate its upstream post-translational modification and downstream regulation. Meanwhile, we describe its role in cancer development and viral infection which provide a direction for future clinical applications.

METHODS

The relevant literatures from PubMed have been reviewed for this article.

CONCLUSION

NOLC1 plays an important role in the progression of multiple cancers and viral infection. In-depth study of NOLC1 provides a new perspective for accurate diagnosis of patients and selection of therapeutic targets.

Low HER2 expression in normal breast epithelium enables dedifferentiation and malignant transformation via chromatin opening

Overexpression of the HER2 protein in breast cancer patients is a predictor of poor prognosis and resistance to therapies. We used an inducible breast cancer transformation system that allows investigation of early molecular changes. HER2 overexpression to similar levels as those observed in a subtype of HER2-positive breast cancer patients induced transformation of MCF10A cells and resulted in gross morphological changes, increased anchorage-independent growth of cells, and altered the transcriptional programme of genes associated with oncogenic transformation. Global phosphoproteomic analysis during HER2 induction predominantly detected an increase in protein phosphorylation. Intriguingly, this correlated with chromatin opening, as measured by ATAC-seq on acini isolated from 3D cell culture. HER2 overexpression resulted in opening of many distal regulatory regions and promoted reprogramming-associated heterogeneity. We found that a subset of cells acquired a dedifferentiated breast stem-like phenotype, making them likely candidates for malignant transformation. Our data show that this population of cells, which counterintuitively enriches for relatively low HER2 protein abundance and increased chromatin accessibility, possesses transformational drive, resulting in increased anchorage-independent growth in vitro compared to cells not displaying a stem-like phenotype.

The role of the nucleolus in regulating the cell cycle and the DNA damage response

The nucleolus has long been perceived as the site for ribosome biogenesis, but numerous studies suggest that the nucleolus carefully sequesters crucial proteins involved in multiple cellular functions. Among these, the role of nucleolus in cell cycle regulation is the most evident. The nucleolus is the first responder of growth-related signals to mediate normal cell cycle progression. The nucleolus also senses different cellular stress insults by activating diverse pathways that arrest the cell cycle, promote DNA repair, or initiate apoptosis. Here, we review the emerging concepts on how the ribosomal and nonribosomal nucleolar proteins mediate such cellular effects.

Atypical chemokine receptor 3 induces colorectal tumorigenesis in mice by promoting β-arrestin-NOLC1-fibrillarin-dependent rRNA biogenesis

Atypical chemokine receptor 3 (ACKR3) has emerged as a key player in various biological processes. Its atypical "intercepting receptor" properties have established ACKR3 as the major regulator in the pathophysiological processes in many diseases. In this study, we investigated the role of ACKR3 activation in promoting colorectal tumorigenesis. We showed that ACKR3 expression levels were significantly increased in human colon cancer tissues, and high levels of ACKR3 predicted the increased severity of cancer. In Villin-ACKR3 transgenic mice with a high expression level of CKR3 in their intestinal epithelial cells, administration of AOM/DSS induced more severe colorectal tumorigenesis than their WT littermates. Cancer cells of Villin-ACKR3 transgenic mice were characterised by the nuclear β-arrestin-1 (β-arr1)-activated perturbation of rRNA biogenesis. In HCT116 cells, cotreatment with CXCL12 and AMD3100 selectively activated ACKR3 and induced nuclear translocation of β-arr1, leading to an interaction of β-arr1 with nucleolar and coiled-body phosphoprotein 1 (NOLC1). NOLC1, as the phosphorylated protein, further interacted with fibrillarin, a conserved nucleolar methyltransferase responsible for ribosomal RNA methylation in the nucleolus, thereby increasing the methylation in histone H2A and promoting rRNA transcription in ribosome biogenesis. In conclusion, ACKR3 promotes colorectal tumorigenesis through the perturbation of rRNA biogenesis by the β-arr1-induced interaction of NOLC1 with fibrillarin.

MDM2 is a useful diagnostic marker for nasopharyngeal carcinoma

BACKGROUND

The MDM2 gene appears to be involved in the development of nasopharyngeal carcinoma. The aim of this study was to examine MDM2 expression in a series of nasopharyngeal carcinoma biopsies to explore its potential diagnostic significance.

METHODS

The study cohort consisted of 26 nasopharyngeal carcinomas, including 22 EBV positive non-keratinizing squamous cell carcinomas (NKSCC), 1 EBV negative NKSCC and 3 EBV negative keratinizing SCC. For comparison, we selected 48 oropharyngeal carcinomas, including 17 HPV positive SCC (14 non-keratinizing and 3 keratinizing) and 31 HPV negative SCCs (28 keratinizing and 3 non-keratinizing). In addition, we examined MDM2 expression in a group of 26 cervical lymph node metastases, including 5 with EBV positive nasopharyngeal NKSCC and 21 from oropharyngeal carcinoma (18 non keratinizing HPV positive, 1 keratinizing HPV positive, 1 keratinizing HPV negative and 1 non-keratinizing HPV negative). Finally, 2 bone metastases from EBV positive nasopharyngeal NKSCC were also included. A tissue microarray was constructed from formalin-fixed paraffin embedded tumor tissue specimens. Sections were immunostained for MDM2 and in situ hybridization for EBER and CISH analysis for the MDM2 gene were also conducted in all cases.

RESULTS

Overall, MDM2 positivity was detected in 28 of 102 SCCs (27.2 %). MDM2 positivity was significantly more frequent in EBV positive NKSCC (80 %) than in oropharyngeal HPV positive NKSCC (6.1 %) and keratinizing SCCs (9.4 %) (p < 0.001, Pearson chi square). Considering only the primary tumors, 86.4 % of the nasopharyngeal carcinomas were positive, versus 13.5 % of the oropharyngeal carcinomas (p < 0.001, Pearson chi square). Considering the lymph node metastases, 3 of 5 EBV positive carcinomas with nasopharyngeal primary were positive, whereas only one of the HPV positive carcinomas was positive. Finally, both the bone metastases from EBV positive nasopharyngeal carcinoma were positive for MDM2. No amplification of the MDM2 gene was identified by in situ hybridization analysis.

CONCLUSIONS

Our data indicate that MDM2 could be a valuable diagnostic marker to support the diagnosis of nasopharyngeal EBV positive NKSCC.

Nucleolar and Coiled-Body Phosphoprotein 1 Is Associated With Stemness and Represents a Potential Therapeutic Target in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and lacks approved specific targeted therapies. One of the major reasons why TNBC is difficult to treat is the high proportion of cancer stem cells within the tumor tissue. Nucleolus is the location of ribosome biogenesis which is frequently overactivated in cancer cells and overactivation of ribosome biogenesis frequently drives the malignant transformation of cancer. Nucleolar and coiled-body phosphoprotein 1 (NOLC1) is a nucleolar protein responsible for nucleolus organization and rRNA synthesis and plays an important role in ribosome biogenesis. However, the correlation of NOLC1 expression with patient prognosis and its value as a therapeutic target have not been evaluated in TNBC. In the current study, based on bioinformatics analysis of the online databases, we found that the expression of NOLC1 was higher in breast cancer tissues than normal tissues, and NOLC1 was expressed at a higher level in TNBC than other subtypes of breast cancer. GSEA analysis revealed that stemness-related pathways were significantly enriched in breast cancer with high NOLC1 gene expression. Further analyses using gene expression profiling interactive analysis 2 (GEPIA2), tumor immune estimation resource (TIMER) and search tool for retrieval of interacting genes/proteins (STRING) demonstrated that NOLC1 was significantly associated with stemness in both all breast cancer and basal-like breast cancer/TNBC patients at both gene and protein levels. Knockdown of NOLC1 by siRNA decreased the protein level of the key stemness regulators MYC and ALDH and inhibited the sphere-forming capacity in TNBC cell line MDA-MB-231. Univariate and multivariate Cox regression analyses demonstrated that NOLC1 was an independent risk factor for overall survival in breast cancer. PrognoScan and Kaplan-Meier plotter analyses revealed that high expression of NOLC1 was associated with poor prognosis in both all breast cancer and TNBC patients. Further immunohistochemical analysis of breast cancer patient samples revealed that TNBC cells had a lower level of NOLC1 in the nucleus compared with non-TNBC cells. These findings suggest that NOLC1 is closely associated with the stemness properties of TNBC and represents a potential therapeutic target for TNBC.

Detection of genomic structure variants associated with wrinkled skin in Xiang pig by next generation sequencing

Wrinkling is prominent manifestation of aging skin. A mutant phenotype characterized by systemic wrinkles and thickened skin was discovered in Xiang pig populations with incidence about 1-3%. The feature in histological structure was epidermal hyperplasia and thickening, collagen fibers disorder. To uncover genetic mechanisms for the mutant phenotype of Xiang pigs with systemic wrinkle (WXP), a genome-wide of structural variations (SVs) in WXP was described by next generation resequencing, taking Xiang pigs (XP) and European pigs (EUP) as compares. Total of 32,308 SVs were detected from three pig groups and 965 SVs were identified specifically from WXP, involving 481 protein-coding genes. These genes were mainly enriched in nuclear structure, ECM components and immunomodulatory pathways. According to gene function and enrichment analysis, we found that 65 candidate SVs in 59 protein genes were probably related with the systemic wrinkle of WXP. Of these, several genes are reported to be associate with aging, such as EIF4G2, NOLC1, XYLT1, FUT8, MDM2 and so on. The insertion/deletion and duplication variations of SVs in these genes resulted in the loss of stop-codon or frameshift mutation, and aberrant alternative splicing of transcripts. These genes are involved in cell lamin filament, intermediate filament cytoskeleton, supramolecular complex, cell differentiation and regulation of macromolecule metabolic process etc. Our study suggested that the loss of function or aberrant expression of these genes lead to structural disorder of nuclear and the extracellular matrix (ECM) in skin cells, which probably was the genetic mechanisms for the mutant phenotype of systemic skin wrinkle of Xiang pig.

Knockdown of NOLC1 Inhibits PI3K-AKT Pathway to Improve the Poor Prognosis of Esophageal Carcinoma

Objective

Esophageal carcinoma (ESCA) is a common malignant gastrointestinal tumor. The abnormal expression of NOLC1 is involved in the tumorigenesis of various human tumors, whereas the function and mechanism of NOLC1 in ESCA remain unclear. In this study, we explored the relationship between NOLC1 and poor prognosis of ESCA, and its role and mechanism in the occurrence of ESCA.

Methods

The NOLC1 expression in ESCA tissues and cell lines was determined by qRT-PCR, immunohistochemistry, or western blot. The Kaplan–Meier method was conducted to estimate the overall survival. Cox regression analysis was carried out to examine the association between patient characteristics and prognosis. A recombined lentiviral vector containing NOLC1 was applied for transfecting ESCA cells (Eca109 and TE-13) and established a stable cell line with low NOLC1 expression or high NOLC1 expression, in the absence or presence of PI3K inhibitor (LY294002) treatment. Cell proliferation, apoptosis rate, invasion ability, migration ability, and PI3K/AKT pathway were detected by CCK8 assay, flow cytometry, Transwell assay, wound-healing assay, and western blot.

Results

NOLC1 overexpression was observed in ESCA tissues and ESCA cell lines (EC9706, Eca109, TE-13, Kyse170, T.TN) compared with adjacent normal tissues and normal esophageal cell line HEEC. NOLC1 overexpression was markedly associated with bigger tumor size, lymph node metastasis, and advanced TNM stage. Patients with NOLC1 overexpression have shorter overall survival than that of those with low NOLC1 expression. NOLC1 overexpression was considered to be an independent poor prognostic factor affecting overall survival. NOLC1 knockdown inhibited proliferation, migration, invasion, and cyclin B1 expression and promoted the apoptosis and cleaved-caspase-3 expression of Eca109 and TE-13 cells. NOLC1 overexpression accelerated proliferation, migration, invasion, and cyclin B1 expression and inhibited the apoptosis and cleaved-caspase-3 expression of ESCA cells via activating PI3K/AKT pathway. Rescue experiments showed that PI3K inhibitor (LY294002) could reverse the phenomenon caused by NOLC1 overexpression.

Conclusion

NOLC1 may be a marker for poor prognosis. It can participate in the occurrence and development of ESCA via the PI3K/AKT pathway.

A Zic2/Runx2/NOLC1 signaling axis mediates tumor growth and metastasis in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is one of the most common malignancies with rapid growth and high metastasis, but lacks effective therapeutic targets. Here, using public sequencing data analyses, quantitative real-time PCR assay, western blotting, and IHC staining, we characterized that runt-related transcription factor 2 (Runx2) was significantly upregulated in ccRCC tissues than that in normal renal tissues, which was associated with the worse survival of ccRCC patients. Overexpression of Runx2 promoted malignant proliferation and migration of ccRCC cells, and inversely, interfering Runx2 with siRNA attenuates its oncogenic ability. RNA sequencing and functional studies revealed that Runx2 enhanced ccRCC cell growth and metastasis via downregulation of tumor suppressor nucleolar and coiled-body phosphoprotein 1 (NOLC1). Moreover, increased Zic family member 2 (Zic2) was responsible for the upregulation of Runx2 and its oncogenic functions in ccRCC. Kaplan-Meier survival analyses indicated that ccRCC patients with high Zic2/Runx2 and low NOLC1 had the worst outcome. Therefore, our study demonstrates that Zic2/Runx2/NOLC1 signaling axis promotes ccRCC progression, providing a set of potential targets and prognostic indicators for patients with ccRCC.

Pten-NOLC1 fusion promotes cancers involving MET and EGFR signalings

Inactivation of Pten gene through deletions and mutations leading to excessive pro-growth signaling pathway activations frequently occurs in cancers. Here, we report a Pten derived pro-cancer growth gene fusion Pten-NOLC1 originated from a chr10 genome rearrangement and identified through a transcriptome sequencing analysis of human cancers. Pten-NOLC1 fusion is present in primary human cancer samples and cancer cell lines from different organs. The product of Pten-NOLC1 is a nuclear protein that interacts and activates promoters of EGFR, c-MET, and their signaling molecules. Pten-NOLC1 promotes cancer proliferation, growth, invasion, and metastasis, and reduces the survival of animals xenografted with Pten-NOLC1-expressing cancer cells. Genomic disruption of Pten-NOLC1 induces cancer cell death, while genomic integration of this fusion gene into the liver coupled with somatic Pten deletion produces spontaneous liver cancers in mice. Our studies indicate that Pten-NOLC1 gene fusion is a driver for human cancers.

Circular RNA CircNOLC1, Upregulated by NF-KappaB, Promotes the Progression of Prostate Cancer via miR-647/PAQR4 Axis

Background

CircRNAs recently have shown critical roles in tumor biology. However, their roles in prostate cancer (PCa) remains largely unclear.

Methods

CircRNA microarrays were performed in immortal prostate cell line RWPE1 and PCa cell lines as DU145, PC3, LNCaP, C4-2, and 22RV1. Combined with upregulated circRNAs in PCa tissues, circNOLC1 expression was validated in PCa cells and tissues via qRT-PCR and FISH. Sanger sequencing, actinomycin D, gDNA, and cDNA, RNase R assays were used to assess the circular characteristics of circNOLC1. CCK-8, colony formation, transwell migration assays, and mice xenograft models were conducted to evaluate the functions of PCa cells after circNOLC1 knockdown and overexpression. RNA pulldown, luciferase reporter assay, FISH (fluorescence in situ hybridization), and CHIP were utilized to illustrate the further mechanisms of circNOLC1.

Results

Our research indicated that circNOLC1 was overexpressed in PCa cells and tissues, and circNOLC1 was more stable than linear NOLC1 mRNA. CircNOLC1 promoted PCa cells proliferation and migration in vitro and vivo. Additionally, we found that circNOLC1 could upregulate PAQR4 expression by sponging miR-647, leading to the activation of PI3K/Akt pathway. Moreover, NF-kappaB was identified to bind to the NOLC1 promoter sites and upregulated both NOLC1 and circNOLC1 expression.

Conclusion

CircNOLC1, elevated by transcription factor NF-kappaB, promotes PCa progression via a miR-647/PAQR4 axis, and circNOLC1 is a potential biomarker and target for PCa treatment.

Identification of Novel Prognosis and Prediction Markers in Advanced Prostate Cancer Tissues Based on Quantitative Proteomics

BACKGROUND/AIM

Prostate cancer (PCa) is the most frequent cancer found in males worldwide, and its mortality rate is increasing every year. However, there are no known molecular markers for advanced or aggressive PCa, and there is an urgent clinical need for biomarkers that can be used for prognosis and prediction of PCa.

MATERIALS AND METHODS

Mass spectrometry-based proteomics was used to identify new biomarkers in tissues obtained from patients with PCa who were diagnosed with T2, T3, or metastatic PCa in regional lymph nodes.

RESULTS

Among 1,904 proteins identified in the prostate tissues, 344 differentially expressed proteins were defined, of which 124 were up-regulated and 216 were down-regulated. Subsequently, based on the results of partial least squares discriminant analysis and Gene Ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analyses, we proposed that spermidine synthase (SRM), nucleolar and coiled-body phosphoprotein 1 (NOLC1), and prostacyclin synthase (PTGIS) represent new protein biomarkers for diagnosis of advanced PCa. These proteomics results were verified by immunoblot assays in metastatic PCa cell lines and by indirect enzyme-linked immunosorbent assay in prostate specimens.

CONCLUSION

SRM was significantly increased depending on the cancer stage, confirming the possibility of using SRM as a biomarker for prognosis and prediction of advanced PCa.

Deciphering the Pharmacological Mechanism of the Herb Radix Ophiopogonis in the Treatment of Nasopharyngeal Carcinoma by Integrating iTRAQ-Coupled 2-D LC-MS/MS Analysis and Network Investigation

The herb Radix Ophiopogonis (RO) has been used effectively to treat nasopharyngeal carcinoma (NPC) as an adjunctive therapy. Due to the complexity of the traditional Chinese herbs, the pharmacological mechanism of RO's action on NPC remains unclear. To address this problem, an integrative approach bridging proteome experiments with bioinformatics prediction was employed. First, differentially expressed protein profile from NPC serum samples was established using isobaric tag for relative and absolute quantification (iTRAQ) coupled 2-D liquid chromatography (LC)-MS/MS analysis. Second, the RO putative targets were predicted using Traditional Chinese Medicines Integrated Database and known therapeutic targets of NPC were collected from Drugbank and OMIM databases. Then, a network between RO putative targets and NPC known therapeutic targets was constructed. Third, based on pathways enrichment analysis, an integrative network was constructed using DAVID and STRING database in order to identify potential candidate targets of RO against NPC. As a result, we identified 13 differentially expressed proteins from clinical experiments compared with the healthy control. And by bioinformatics investigation, 12 putative targets of RO were selected. Upon interactions between experimental and predicted candidate targets, we identified three key candidate targets of RO against NPC: VEGFA, TP53, and HSPA8, by calculating the nodes' topological features. In conclusion, this integrative pharmacology-based analysis revealed the anti-NPC effects of RO might be related to its regulatory impact via the PI3K-AKT signaling pathway, the Wnt signaling pathway, and the cAMP signaling pathway by targeting VEGFA, TP53, and HSPA8. The findings of potential key targets may provide new clues for NPC's treatments with the RO adjunctive therapy.

Identification and validation of NOLC1 as a potential target for enhancing sensitivity in multidrug resistant non-small cell lung cancer cells

Adjuvant chemotherapy has become the frequently adopted standard therapeutic approach for non-small cell lung cancer (NSCLC). However, the development of multidrug resistance (MDR) is a major obstacle contributing to the failure of chemotherapy. This study aimed to identify genes associated with MDR development that predict tumor response to chemotherapy in NSCLC. In the present study, a multidrug-resistant NSCLC cell sub-line, A549/MDR, was established from the A549/DDP cell line and characterized. The resistance index (RI) of this subline was calculated according to the IC50 of A549/MDR relative to the parental A549/DDP cells. The gene expression profiles of A549/DDP and A549/MDR were obtained using an oligonucleotide microarray (Agilent SureHyb microarray chip). The microarray results were validated by qRT-PCR and selected genes were analyzed by in vitro loss-of-function experiments. Gene expression profiling identified 921 differentially expressed genes (DEGs) according to the selection criteria, in which 541 genes were upregulated and 380 genes were downregulated in A549/MDR compared with A549/DDP cells. We found that these DEGs are involved in diverse biological processes, including ribonucleoprotein complex, drug metabolism, the Hippo signaling pathway and transcriptional misregulation. NOLC1, as one of the identified DEGs, was confirmed to be overexpressed in A549/MDR cells and its knockdown significantly enhanced the drug sensitivity of A549/MDR cells in response to multidrug treatment. Furthermore, knockdown of NOLC1 downregulated the expression levels of drug resistance-associated molecules (LRP and MDR1) in A549/MDR cells. These findings provide a new and comprehensive expression profile of MDR in NSCLC cells. Identification and validation of NOLC1 might be a promising therapeutic strategy for the management of MDR of NSCLC patients.

NS5ATP13 Promotes Liver Fibrogenesis Via Activation of Hepatic Stellate Cells

Liver fibrosis is a reversible wound-healing response to any etiology of chronic hepatic injuries. Activation of hepatic stellate cells (HSCs) is the key event in liver fibrogenesis. Generally, persistent activation and proliferation of HSCs results in liver fibrosis progression, while primary mechanisms of liver fibrosis resolution are apoptosis and reversion to a quiescent phenotype of activated HSCs. NS5ATP13 (HCV NS5A-transactivated protein 13) is involved in nucleologenesis and tumorigenesis, but its role in liver fibrosis and HSC activation remains unclear. This study found that NS5ATP13 was upregulated in both fibrotic liver tissues and activated human HSCs induced by TGF-β1. Moreover, NS5ATP13 enhanced extracellular matrix (ECM) production and HSC activation, with or without TGF-β1 treatment, likely involving the TGF-β1/Smad3 signaling pathway. Additionally, NS5ATP13 boosted HSC proliferation by inhibiting cell apoptosis. Furthermore, HCV NS5A promoted the profibrogenic effect of NS5ATP13 partly through TGF-β1 and NF-κB p65 (RelA) upregulation. Meanwhile, NS5ATP13 was required for the pro-fibrogenic effect of NF-κB. Moreover, NS5ATP13 and NF-κB phosphorylation as well as HSC activation were reduced by CX-4945, a CK2 specific inhibitor. These findings indicated that NS5ATP13 acts as a profibrogenic factor, providing a potential target for antifibrotic therapies. J. Cell. Biochem. 118: 2463-2473, 2017. © 2017 Wiley Periodicals, Inc.

Therapeutic targeting of the MYC signal by inhibition of histone chaperone FACT in neuroblastoma

Amplification of the MYCN oncogene predicts treatment resistance in childhood neuroblastoma. We used a MYC target gene signature that predicts poor neuroblastoma prognosis to identify the histone chaperone FACT (facilitates chromatin transcription) as a crucial mediator of the MYC signal and a therapeutic target in the disease. FACT and MYCN expression created a forward feedback loop in neuroblastoma cells that was essential for maintaining mutual high expression. FACT inhibition by the small-molecule curaxin compound CBL0137 markedly reduced tumor initiation and progression in vivo. CBL0137 exhibited strong synergy with standard chemotherapy by blocking repair of DNA damage caused by genotoxic drugs, thus creating a synthetic lethal environment in MYCN-amplified neuroblastoma cells and suggesting a treatment strategy for MYCN-driven neuroblastoma.

Ethanolic Extracts of Pluchea indica Induce Apoptosis and Antiproliferation Effects in Human Nasopharyngeal Carcinoma Cells

Pluchea indica is used in traditional medicine for the treatment of lumbago, ulcer, tuberculosis and inflammation. The anti-cancer activities and the underlying molecular mechanisms of the ethanolic extracts of P. indica root (PIRE) were characterized in the present study. PIRE strongly inhibited the viability of the human nasopharyngeal carcinoma cells (NPC-TW 01 and NPC-TW 04) in a time- and dose-dependent manner. Migration of cancer cells was also suppressed by PIRE. In addition, PIRE significantly increased the occurrence of the cells in sub-G1 phase and the extent of DNA fragmentation in a dose-dependent manner, which indicates that PIRE significantly increased apoptosis in NPC cells. The apoptotic process triggered by PIRE involved up-regulation of pro-apoptotic Bax protein and down-regulation of anti-apoptotic Bcl-2 protein, consequently increasing the ratios of Bax/Bcl-2 protein levels. Moreover, the p53 protein was up-regulated by PIRE in a concentration-dependent manner. Therefore, PIRE could induce the apoptosis-signaling pathway in NPC cells by activation of p53 and by regulation of apoptosis-related proteins.

Functional screening identifies miRNAs influencing apoptosis and proliferation in colorectal cancer

MicroRNAs (miRNAs) play a critical role in many biological processes and are aberrantly expressed in human cancers. Particular miRNAs function either as tumor suppressors or oncogenes and appear to have diagnostic and prognostic significance. Although numerous miRNAs are dys-regulated in colorectal cancer (CRC) only a small fraction has been characterized functionally. Using high-throughput functional screening and miRNA profiling of clinical samples the present study aims at identifying miRNAs important for the control of cellular growth and/or apoptosis in CRC. The high-throughput functional screening was carried out in six CRC cell lines transfected with a pre-miR library including 319 synthetic human pre-miRs. Phenotypic alterations were evaluated by immunostaining of cleaved cPARP (apoptosis) or MKI67 (proliferation). Additionally, TaqMan Human MicroRNA Array Set v2.0 was used to profile the expression of 667 miRNAs in 14 normal colon mucosa and 46 microsatellite stable stage II CRC patients. Among the miRNAs that induced growth arrest and apoptosis in the CRC cell lines, and at same time were dys-regulated in the clinical samples, miR-375 was selected for further analysis. Independent in vitro analysis of transient and stable transfected CRC cell lines confirmed that miR-375 reduces cell viability through the induction of apoptotic death. We identified YAP1 as a direct miR-375 target in CRC and show that HELLS and NOLC1 are down-stream targets. Knock-down of YAP1 mimicked the phenotype induced by miR-375 over-expression indicating that miR-375 most likely exerts its pro-apoptotic role through YAP1 and its anti-apoptotic down-stream targets BIRC5 and BCL2L1. Finally, in vivo analysis of mouse xenograft tumors showed that miR-375 expression significantly reduced tumor growth. We conclude that the high-throughput screening successfully identified miRNAs that induce apoptosis and/or inhibit proliferation in CRC cells. Finally, combining the functional screening with profiling of CRC tissue samples we identified clinically relevant miRNAs and miRNA targets in CRC.

Screening E3 substrates using a live phage display library

Ubiquitin ligases (E3s) determine specificity of ubiquitination by recognizing target substrates. However, most of their substrates are unknown. Most known substrates have been identified using distinct approaches in different laboratories. We developed a high-throughput strategy using a live phage display library as E3 substrates in in vitro screening. His-ubiquitinated phage, enriched with Ni-beads, could effectively infect E. coli for amplification. Sixteen natural potential substrates and many unnatural potential substrates of E3 MDM2 were identified through 4 independent screenings. Some substrates were identified in different independent experiments. Additionally, 10 of 12 selected candidates were ubiquitinated by MDM2 in vitro, and 3 novel substrates, DDX42, TP53RK and RPL36a were confirmed ex vivo. The whole strategy is rather simple and efficient. Non-degradation substrates can be discovered. This strategy can be extended to any E3s as long as the E3 does not ubiquitinate the empty phage.

Methylation of nucleolar and coiled-body phosphoprotein 1 is associated with the mechanism of tumorigenesis in hepatocellular carcinoma

Nucleolar and coiled-body phosphoprotein 1 (NOLC1) plays an essential role in the synthesis of rRNA and the biosynthesis of ribosomes. Previous studies suggest that NOLC1 is crucial for normal cell growth, and plays a role in the regulation of tumorigenesis of nasopharyngeal carcinoma (NPC) and demonstrate that both NOLC1 and tumor protein 53 work synergistically to activate the MDM2 promoter in NPC cells. Yet, the functioning of NOLC1 in liver cancer remains unknown. The aim of the present study was to understand how the NOLC1 gene is regulated in liver carcinogenesis. In this study, we showed that NOLC1 was silenced or downregulated in liver tumor tissues when compared with that in the matched non-cancer tissues. In addition, human hepatoma cells weakly expressed NOLC1, whereas cultured human normal liver cell lines expressed abundant levels. The hypermethylation status in the promoter CpG1 start region appeared to be correlated with the NOLC1 expression levels in liver cell lines or liver normal and tissue specimens. We found that four CpG dinucleotides were located at the CpG1 start region. Further molecular analysis of mutagenesis indicated that the four CpG dinucleotides play a role in the promoter activity of the NOLC1 gene. The expression of NOLC1 and DNA methylation of its promoter affected cell proliferation and apoptosis. The expression of NOLC1 in hepatoma cell lines was restored following exposure to the demethylation agent, 5-azacytidine. Low expression of NOLC1 in hepatoma cell lines and liver cancer tissues was associated with cyclin D3. In conclusion, our study demonstrated that DNA methylation is a key mechanism of silenced NOLC1 expression in human hepatocellular carcinoma cells, and NOLC1 gene hypermethylation of the four CpG dinucleotides is a potential biomarker for hepatocellular carcinoma.

Interaction of avian influenza virus NS1 protein and nucleolar and coiled-body phosphoprotein 1

Nonstructural protein 1 (NS1) is a non-structural protein of avian influenza virus. It can interact with a variety of proteins of the host cells, enhancing the expression of viral proteins and changing the growth and metabolism of the host cells, thereby enhancing the virus’ pathogenicity and virulence. To investigate whether there are more host proteins that can interact with NS1 during viral infection, T7-phage display system was used to screen human lung cell cDNA library for proteins that could interact with NS1. One positive and specific clone was obtained and identified as nucleolar and coiled-body phosphoprotein 1(NOLC1). The interaction between these two proteins was further demonstrated by His-pull-down and co-immunoprecipitation experiments. Co-expression of both proteins in HeLa cell showed that NS1 and NOLC1 were co-localized in the cell’s nucleus. Gene truncation experiments revealed that the effector domain of NS1 was sufficient to interact with NOLC1. The results demonstrated a positive interaction between a viral NS1 and NOLC1 of the host cells, and provided a new target for drug screening.