CREB-binding protein regulates lung cancer growth by targeting MAPK and CPSF4 signaling pathway

Modulation of diverse biological processes by CPSF, the master regulator of mRNA 3' ends

The cleavage and polyadenylation specificity factor (CPSF) complex plays a central role in the formation of mRNA 3' ends, being responsible for the recognition of the poly(A) signal sequence, the endonucleolytic cleavage step, and recruitment of poly(A) polymerase. CPSF has been extensively studied for over three decades, and its functions and those of its individual subunits are becoming increasingly well-defined, with much current research focusing on the impact of these proteins on the normal functioning or disease/stress states of cells. In this review, we provide an overview of the general functions of CPSF and its subunits, followed by a discussion of how they exert their functions in a surprisingly diverse variety of biological processes and cellular conditions. These include transcription termination, small RNA processing, and R-loop prevention/resolution, as well as more generally cancer, differentiation/development, and infection/immunity.

Knockdown of CPSF4 Inhibits Bladder Cancer Cell Growth by Upregulating NRF1

Increasing studies have shown that nuclear respiratory factor 1 (NRF1) deficiency frequently occurs in many human diseases, and its activation can protect neurons and other cells from degenerative diseases and malignant tumors. However, how NRF1 is regulated in bladder cancer remains unknown. Our research aims to reveal the role of leavage and polyadenylation-specific factor 4 (CPSF4) on the growth inhibition effect of bladder cancer and clarify its relationship with NRF1. Here, cell proliferation assay, transwell migration assay and multicellular tumor spheroids (MCTS) formation assay in the bladder cancer cell lines were carried out to measure tumor cell growth. Western bolt assay was carried out to identify the relationship between NRF1 and CPSF4. Also, subcutaneous xenograft tumors in nude mice were established to further validate the inhibition effect of CPSF4 on bladder tumor and the regulation on NRF1. The results in vitro showed that knockdown of CPSF4 strongly reduced the proliferation and migration, and inhibited MCTS formation in 5637 and HT1376 cell lines, while an additional knockdown of increased NRF1 induced by CPSF4 knockdown partially abolished these effects. The results in vivo showed that knockdown of CPSF4 strongly reduced the volume and weight of subcutaneous tumor, and decreased the expression of Ki-67 in tumor tissue, while NRF1 knockdown partially reversed these effects induced by CPSF4 knockdown. Western bolt assay demonstrated that CPSF4 could negatively regulate NRF1. Our results indicated that knock-down of CPSF4 inhibited bladder cancer cell growth by upregulating NRF1, which might provide evidence of CPSF4 as a therapeutic target for bladder cancer.

Cleavage and Polyadenylation-Specific Factor 4 (CPSF4) Expression Is Associated with Enhanced Prostate Cancer Cell Migration and Cell Cycle Dysregulation, In Vitro

Potential oncogene cleavage and polyadenylation specific factor 4 (CPSF4) has been linked to several cancer types. However, little research has been conducted on its function in prostate cancer (PCa). In benign, incidental, advanced, and castrate resistant PCa (CRPCa) patient samples, protein expression of CPSF4 was examined on tissue microarray (TMAs) of 353 PCa patients using immunohistochemistry. Using the 'The Cancer Genome Atlas' Prostate Adenocarcinoma (TCGA PRAD) database, significant correlations were found between high CPSF4 expression and high-risk genomic abnormalities such as ERG-fusion, ETV1-fusion, and SPOP mutations. Gene Set Enrichment Analysis (GSEA) of CPSF4 revealed evidence for the increase in biological processes such as cellular proliferation and metastasis. We further examined the function of CPSF4 in vitro and confirmed CPSF4 clinical outcomes and its underlying mechanism. Our findings showed a substantial correlation between Gleason groups and CPSF4 protein expression. In vitro, CPSF4 knockdown reduced cell invasion and migration while also causing G1 and G2 arrest in PC3 cell lines. Our findings demonstrate that CPSF4 may be used as a possible biomarker in PCa and support its oncogenic function in cellular proliferation and metastasis.

Landscape of Genetic Mutations in Appendiceal Cancers

In appendiceal cancers, the most frequently mutated genes are (i) KRAS, which, when reactivated, restores signal transduction via the RAS-RAF-MEK-ERK signaling pathway and stimulates cell proliferation in the early stages of tumor transformation, and then angiogenesis; (ii) TP53, whose inactivation leads to the inhibition of programmed cell death; (iii) GNAS, which, when reactivated, links the cAMP pathway to the RAS-RAF-MEK-ERK signaling pathway, stimulating cell proliferation and angiogenesis; (iv) SMAD4, exhibiting typical tumor-suppressive activity, blocking the transmission of oncogenic TGFB signals via the SMAD2/SMAD3 heterodimer; and (v) BRAF, which is part of the RAS-RAF-MEK-ERK signaling pathway. Diverse mutations are reported in other genes, which are part of secondary or less critical signaling pathways for tumor progression, but which amplify the phenotypic diversity of appendiceal cancers. In this review, we will present the main genetic mutations involved in appendix tumors and their roles in cell proliferation and survival, and in tumor invasiveness, angiogenesis, and acquired resistance to anti-growth signals.

Identification of Somatic Mutations in Plasma Cell-Free DNA from Patients with Metastatic Oral Squamous Cell Carcinoma

The accurate diagnosis and treatment of oral squamous cell carcinoma (OSCC) requires an understanding of its genomic alterations. Liquid biopsies, especially cell-free DNA (cfDNA) analysis, are a minimally invasive technique used for genomic profiling. We conducted comprehensive whole-exome sequencing (WES) of 50 paired OSCC cell-free plasma with whole blood samples using multiple mutation calling pipelines and filtering criteria. Integrative Genomics Viewer (IGV) was used to validate somatic mutations. Mutation burden and mutant genes were correlated to clinico-pathological parameters. The plasma mutation burden of cfDNA was significantly associated with clinical staging and distant metastasis status. The genes TTN, PLEC, SYNE1, and USH2A were most frequently mutated in OSCC, and known driver genes, including KMT2D, LRP1B, TRRAP, and FLNA, were also significantly and frequently mutated. Additionally, the novel mutated genes CCDC168, HMCN2, STARD9, and CRAMP1 were significantly and frequently present in patients with OSCC. The mutated genes most frequently found in patients with metastatic OSCC were RORC, SLC49A3, and NUMBL. Further analysis revealed that branched-chain amino acid (BCAA) catabolism, extracellular matrix-receptor interaction, and the hypoxia-related pathway were associated with OSCC prognosis. Choline metabolism in cancer, O-glycan biosynthesis, and protein processing in the endoplasmic reticulum pathway were associated with distant metastatic status. About 20% of tumors carried at least one aberrant event in BCAA catabolism signaling that could possibly be targeted by an approved therapeutic agent. We identified molecular-level OSCC that were correlated with etiology and prognosis while defining the landscape of major altered events of the OSCC plasma genome. These findings will be useful in the design of clinical trials for targeted therapies and the stratification of patients with OSCC according to therapeutic efficacy.

A novel nomogram for predicting overall survival in peripheral T cell lymphoma patients.. [DOI: 10.21203/rs.3.rs-2823604/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Background The prognosis of peripheral T cell lymphomas (PTCLs) varies greatly. This study aimed at generating a prognostic nomogram based on differentially expressed genes (DEGs).Methods Firstly, we collected RNA transcripts from Gene Expression Omnibus and identified DEGs. Secondly we used univariate Cox regression, Least absolute shrinkage and selection operator (LASSO) to screen the independent risk factors to construct nomogram in the training cohort. Thirdly, we evaluate its prediction accuracy via decision curves analysis (DCA), receiver operating characteristic (ROC) and calibration rate to confirm its performance on survival in training and validation cohort. Then we carried out subgroup analysis in training and validation to eliminate the effects of age, gender, and pathological subtype. Lastly, to verify feasibility of nomogram in practice, we applied immunohistochemistry to clinical samples and analyzed the relationship between IHC scores and prognosis.Results The 702 DEGs between 40 PTCLs and 20 non-tumor patients were identified. Then ANGPTL2, CPSF4, CLIC4 and OTUD6B were screened out as independent risk factors via univariate Cox regression and LASSO. The DCA, ROC, Harrell’s concordance index (c-index) and calibration rate showed nomogram predicting more accurately than any single specific transcript. The results showed PTCLs with higher nomogram-score had a longer survival, regardless of age, gender and pathological subtype. Finally, the high expression level of ANGPTL2, CPSF4 and OTUD6B related to poor prognosis. Higher expression of CLIC4 related to longer survival.Conclusion This nomogram showed the favorable clinical applicability, regardless of age, gender and pathological subtype.

Pharmacological targeting of CBP/p300 drives a redox/autophagy axis leading to senescence-induced growth arrest in non-small cell lung cancer cells

p300/CBP histone acetyltransferases (HAT) are critical transcription coactivators involved in multiple cellular activities. They act at multiple levels in non-small cell lung carcinoma (NSCLC) and appear, therefore, as promising druggable targets. Herein, we investigated the biological effects of A-485, the first selective (potent) drug-like HAT catalytic inhibitor of p300/CBP, in human NSCLC cell lines. A-485 treatment specifically reduced p300/CBP-mediated histone acetylation marks and caused growth arrest of lung cancer cells via activation of the autophagic pathway. Indeed, A-485 growth-arrested cells displayed phenotypic markers of cell senescence and failed to form colonies. Notably, disruption of autophagy by genetic and pharmacological approaches triggered apoptotic cell death. Mechanistically, A-485-induced senescence occurred through the accumulation of reactive oxygen species (ROS), which in turn resulted in DNA damage and activation of the autophagic pathway. Interestingly, ROS scavengers were able to revert senescence phenotype and restore cell viability, suggesting that ROS production had a key role in upstream events leading to growth arrest commitment. Altogether, our data provide new insights into the biological effects of the A-485 and uncover the importance of the autophagic/apoptotic response to design a new combinatorial anticancer strategy.

Regulation of SUMOylation on RNA metabolism in cancers

Post-translational modifications of proteins play very important roles in regulating RNA metabolism and affect many biological pathways. Here we mainly summarize the crucial functions of small ubiquitin-like modifier (SUMO) modification in RNA metabolism including transcription, splicing, tailing, stability and modification, as well as its impact on the biogenesis and function of microRNA (miRNA) in particular. This review also highlights the current knowledge about SUMOylation regulation in RNA metabolism involved in many cellular processes such as cell proliferation and apoptosis, which is closely related to tumorigenesis and cancer progression.

CPSF4 promotes tumor-initiating phenotype by enhancing VEGF/NRP2/TAZ signaling in lung cancer

Lung cancer is the leading cause of malignant tumor-related deaths worldwide. The presence of tumor-initiating cells in lung cancer leads to tumor recurrence, metastasis, and resistance to conventional treatment. Cleavage and polyadenylation specificity factor 4 (CPSF4) activation in tumor cells contributes to the poor prognosis of lung cancer. However, the precise biological functions and molecular mechanisms of CPSF4 in the regulation of tumor-initiating cells remain unclear. We demonstrated that CPSF4 promotes tumor-initiating phenotype and confers chemoresistance to paclitaxel both in vitro and in vivo. Mechanistically, we showed that CPSF4 binds to the promoters of vascular endothelial growth factor (VEGF) and neuropilin-2 (NRP2) and activated their transcription. In addition, we showed that CPSF4/VEGF/NRP2-mediated tumor-initiating phenotype and chemoresistance through TAZ induction. Furthermore, analysis of clinical data revealed that lung cancer patients with high CPSF4 expression exhibit high expression levels of VEGF, NRP2, and TAZ and that expression of these proteins are positively correlated with poor prognosis. Importantly, selective inhibition of VEGF, NRP2, or TAZ markedly suppressed CPSF4-mediated tumor-initiating phenotype and chemoresistance. Our findings reveal the mechanism of CPSF4 modulating tumor-initiating phenotype and chemoresistance in lung cancer and indicate that the CPSF4-VEGF-NRP2-TAZ signaling pathway may be a prognosis marker and therapeutic target in lung cancer.

Bioinformatics analysis reveals the potential target of rosiglitazone as an antiangiogenic agent for breast cancer therapy

Background

Several studies have demonstrated the antitumor activity of rosiglitazone (RGZ) in cancer cells, including breast cancer cells. However, the molecular targets of RGZ in the inhibition of angiogenesis in breast cancer cells remain unclear. This study aimed to explore the potential targets of RGZ in inhibiting breast cancer angiogenesis using bioinformatics-based analysis.

Results

Venn diagram analysis revealed 29 TR proteins. KEGG pathway enrichment analysis demonstrated that TR regulated the adipocytokine, AMPK, and PPAR signaling pathways. Oncoprint analysis showed genetic alterations in FABP4 (14%), ADIPOQ (2.9%), PPARG (2.8%), PPARGC1A (1.5%), CD36 (1.7%), and CREBBP (11%) in patients with breast cancer in a TCGA study. The mRNA levels of FABP4, ADIPOQ, PPARG, CD36, and PPARGC1A were significantly lower in patients with breast cancer than in those without breast cancer. Analysis of gene expression using bc-GenExMiner showed that the mRNA levels of FABP, ADIPOQ, PPARG, CD36, PPARGC1A, and CREBBP were significantly lower in basal-like and triple-negative breast cancer (TNBC) cells than in non-basal-like and non-TNBC cells. In general, the protein levels of these genes were low, except for that of CREBBP. Patients with breast cancer who had low mRNA levels of FABP4, ADIPOQ, PPARG, and PPARGC1A had lower overall survival rates than those with high mRNA levels, which was supported by the overall survival related to DNA methylation. Correlation analysis of immune cell infiltration with TR showed a correlation between TR and immune cell infiltration, highlighting the potential of RGZ for immunotherapy.

Conclusion

This study explored the potential targets of RGZ as antiangiogenic agents in breast cancer therapy and highlighted FABP4, ADIPOQ, PPARG, PPARGC1A, CD36, and CREBBP as potential targets of RGZ. These findings require further validation to explore the potential of RGZ as an antiangiogenic agent.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12863-022-01086-2.

Recent studies have focused on the development of indirect angiogenesis inhibitors.

Bioinformatics-based identification of potential rosiglitazone target genes to inhibit breast cancer angiogenesis.

FABP4, ADIPOQ, PPARG, PPARGC1A, CD36, and CREBBP are potential targets of rosiglitazone.

Interpreting Functional Impact of Genetic Variations by Network QTL for Genotype–Phenotype Association Study

An enormous challenge in the post-genome era is to annotate and resolve the consequences of genetic variation on diverse phenotypes. The genome-wide association study (GWAS) is a well-known method to identify potential genetic loci for complex traits from huge genetic variations, following which it is crucial to identify expression quantitative trait loci (eQTL). However, the conventional eQTL methods usually disregard the systematical role of single-nucleotide polymorphisms (SNPs) or genes, thereby overlooking many network-associated phenotypic determinates. Such a problem motivates us to recognize the network-based quantitative trait loci (QTL), i.e., network QTL (nQTL), which is to detect the cascade association as genotype → network → phenotype rather than conventional genotype → expression → phenotype in eQTL. Specifically, we develop the nQTL framework on the theory and approach of single-sample networks, which can identify not only network traits (e.g., the gene subnetwork associated with genotype) for analyzing complex biological processes but also network signatures (e.g., the interactive gene biomarker candidates screened from network traits) for characterizing targeted phenotype and corresponding subtypes. Our results show that the nQTL framework can efficiently capture associations between SNPs and network traits (i.e., edge traits) in various simulated data scenarios, compared with traditional eQTL methods. Furthermore, we have carried out nQTL analysis on diverse biological and biomedical datasets. Our analysis is effective in detecting network traits for various biological problems and can discover many network signatures for discriminating phenotypes, which can help interpret the influence of nQTL on disease subtyping, disease prognosis, drug response, and pathogen factor association. Particularly, in contrast to the conventional approaches, the nQTL framework could also identify many network traits from human bulk expression data, validated by matched single-cell RNA-seq data in an independent or unsupervised manner. All these results strongly support that nQTL and its detection framework can simultaneously explore the global genotype–network–phenotype associations and the underlying network traits or network signatures with functional impact and importance.

The integrated stress response is tumorigenic and constitutes a therapeutic liability in KRAS-driven lung cancer

The integrated stress response (ISR) is an essential stress-support pathway increasingly recognized as a determinant of tumorigenesis. Here we demonstrate that ISR is pivotal in lung adenocarcinoma (LUAD) development, the most common histological type of lung cancer and a leading cause of cancer death worldwide. Increased phosphorylation of the translation initiation factor eIF2 (p-eIF2α), the focal point of ISR, is related to invasiveness, increased growth, and poor outcome in 928 LUAD patients. Dissection of ISR mechanisms in KRAS-driven lung tumorigenesis in mice demonstrated that p-eIF2α causes the translational repression of dual specificity phosphatase 6 (DUSP6), resulting in increased phosphorylation of the extracellular signal-regulated kinase (p-ERK). Treatments with ISR inhibitors, including a memory-enhancing drug with limited toxicity, provides a suitable therapeutic option for KRAS-driven lung cancer insofar as they substantially reduce tumor growth and prolong mouse survival. Our data provide a rationale for the implementation of ISR-based regimens in LUAD treatment.

A Crosstalk between Diet, Microbiome and microRNA in Epigenetic Regulation of Colorectal Cancer

A still growing interest between human nutrition in relation to health and disease states can be observed. Dietary components shape the composition of microbiota colonizing our gastrointestinal tract which play a vital role in maintaining human health. There is a strong evidence that diet, gut microbiota and their metabolites significantly influence our epigenome, particularly through the modulation of microRNAs. These group of small non-coding RNAs maintain cellular homeostasis, however any changes leading to impaired expression of miRNAs contribute to the development of different pathologies, including neoplastic diseases. Imbalance of intestinal microbiota due to diet is primary associated with the development of colorectal cancer as well as other types of cancers. In the present work we summarize current knowledge with particular emphasis on diet-microbiota-miRNAs axis and its relation to the development of colorectal cancer.

Identification of consistent post-translational regulatory triplets related to oncogenic and tumour suppressive modulators in childhood acute lymphoblastic leukemia

Background

Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer. It can be caused by mutations that turn on oncogenes or turn off tumour suppressor genes. For instance, changes in certain genes including Rb and p53 are common in ALL cells. Oncogenes and TSGs may serve as a modulator gene to regulate the gene expression level via their respective target genes. To investigate the regulatory relationship between oncogenes, tumour suppressor genes and transcription factors at the post translational level in childhood ALL, we performed an integrative network analysis on the gene regulation in the post-translational level for childhood ALL based on many publicly available cancer gene expression data including TARGET and GEO database.

Methods

We collected 259 childhood ALL-related genes from the latest online leukemia database, Leukemia Gene Literature Database. These 259 genes were selected from a comprehensive systematic literature with experimental evidences. The identified and curated genes were also associated with patient survival cases and we incorporated this pediatric ALL-related gene list into our analysis. We extracted the known human TFs from the TRRUST database. Among 259 childhood ALL-related genes, 101 unique regulators were mapped to the list of oncogene and tumour suppressor genes (TSGs) from the ONGene and the TSGene databases, and these included 74 TSGs, 62 oncogenes and 46 TF genes.

Results

The resulted regulation was presented as a hierarchical regulatory network with transcription factors (TFs) as intermediate regulators connecting the top modulators (oncogene and TSGs) to the common target genes. Cross-validation was applied to the results from the TARGET dataset by identifying the consistent regulatory motifs based on three independent ALL expression datasets. A three-layer regulatory network of consistent positive modulators in childhood ALL was constructed in which 74 modulators (40 oncogenes, 34 TSGs) are considered as the most important regulators. The middle layer and the bottom layer contain 34 TFs and 176 target genes, respectively. Oncogenes mostly participated in positive regulation of gene expression and the transcription process of RNA II polymerase, while TSGs were mainly involved in the negative regulation of gene expression. In addition, the oncogene-specific targets were enriched with regulators of the MAPK cascade while tumour suppressor-specific targets were associated with cell death.

Conclusion

The results revealed that oncogenes and TSGs possess a different functional regulatory pattern with regard to not only their biological functions but also their specific target genes in childhood ALL cancer progression. Taken together, our findings could contribute to a better understanding of the important regulatory mechanisms and this method could be used to analyse the targeted genes at the post-translational level in childhood ALL through integrative network analysis.

Identification of CDKL3 as a critical regulator in development of glioma through regulating RRM2 and the JNK signaling pathway

Glioma is one of the most commonly diagnosed intracranial malignancies. The molecular mechanism underlying the development of glioma is still largely unknown. In this study, we present the first report concerning the function and mechanism of cyclin‐dependent kinase‐like 3 (CDKL3) in the development and prognosis of glioma. It is shown that CDKL3 was upregulated in glioma tissues and could independently predict poor prognosis of patients. Silencing CDKL3 in glioma cells could inhibit cell proliferation and migration and induce cell apoptosis and cell cycle arrest, whereas the overexpression of CDKL3 promoted cell proliferation. The in vivo experiments also indicated that knockdown of CDKL3 significantly suppressed tumor growth of glioma. Gene expression profiling of CDKL3 knockdown U87 cells identified RRM2 as a potential target of CDKL3, which was proved to have direct interaction with CDKL3. Given similar effects on glioma development with CDKL3, knockdown of RRM2 could rescue the effects of CDKL3 overexpression on glioma cells. Moreover, knockdown of CDKL3 or RRM2 suppressed the activity of JNK signaling, whereas CDKL3 overexpression produced the opposite effect. In conclusion, our results identified CDKL3 as a promotor for glioma, probably through the regulation of RRM2 and activation of the JNK signalling pathway, highlighting the significance of CDKL3 as a promising therapeutic target of glioma.

Determining protein-protein functional associations by functional rules based on gene ontology and KEGG pathway

Protein-protein interactions (PPIs) describe the direct physical contact of two proteins that usually results in specific biological functions or regulatory processes. The characterization and study of PPIs through the investigation of their pattern and principle have remained a question in biological studies. Various experimental and computational methods have been used for PPI studies, but most of them are based on the sequence similarity with current validated PPI participators or cellular localization patterns. Most methods ignore the fact that PPIs are defined by their specific biological functions. In this study, we constructed a novel rule-based computational method using gene ontology and KEGG pathway annotation of PPI participators that correspond to the complicated biological effects of PPIs. Our newly presented computational method identified a group of biological functions that are tightly associated with PPIs and provided a new function-based tool for PPI studies in a rule manner.

Overproduced CPSF4 Promotes Cell Proliferation and Invasion via PI3K-AKT Signaling Pathway in Oral Squamous Cell Carcinoma

PURPOSE

Invasion and metastasis are major challenges in the treatment of oral cancer. We hypothesize that cleavage and polyadenylation specific factor 4 (CPSF4), a key mediator of cell growth and metastasis in several types of cancers, contributes to oral squamous cell carcinoma (OSCC) pathogenesis.

MATERIALS AND METHODS

The expression and production of CPSF4 in OSCC cell lines and tumor tissues were assessed by RT-PCR and western blot, respectively. The relationships between CPSF4 production and OSCC clinicopathological features were analyzed using immunohistochemistry. The effects of CPSF4 on viability, proliferation, migration, invasion, cell cycle distribution, and apoptosis of OSCC cells were measured by MTS assay, colony formation assay, wound-healing, transwell invasion assay, flow cytometry, and cell apoptosis assay, respectively. Western blot analysis was used to assess alteration of PI3K-AKT pathway member levels in cell lines transfected with CPSF4 siRNA. Mice xenograft models were used to determine the effect of CPSF4 on OSCC tumor growth in vivo.

RESULTS

CPSF4 was highly expressed in OSCC cell lines and tumor tissues compared with adjacent normal oral tissues. High CPSF4 expression was strongly correlated with vascular invasion (P = .004), distant metastasis (P = .001), and TNM stages (P = .001). Moreover, reduction of CPSF4 levels contributed to the inhibition of cell viability, proliferation, invasion and migration, and the induction of apoptosis in OSCC cell lines. Reduction of CPSF4 levels results in OSCC cell cycle arrest in G1 phase by targeting c-Myc. CPSF4 contributed to proliferation inhibition via PI3K-AKT signaling pathway. Reduction of CPSF4 levels inhibits OSCC tumor growth in vivo.

CONCLUSIONS

Our results suggest that CPSF4 supports OSCC invasion and metastasis and may be a promising therapeutic target for OSCC.

Distal lung epithelial progenitor cell function declines with age

Tissue stem cell exhaustion is a key hallmark of aging, and in this study, we characterised its manifestation in the distal lung. We compared the lungs of 3- and 22-month old mice. We examined the gross morphological changes in these lungs, the density and function of epithelial progenitor populations and the epithelial gene expression profile. Bronchioles became smaller in their cross-sectional area and diameter. Using long-term EdU incorporation analysis and immunohistochemistry, we found that bronchiolar cell density remained stable with aging, but inferred rates of bronchiolar club progenitor cell self-renewal and differentiation were reduced, indicative of an overall slowdown in cellular turnover. Alveolar Type II progenitor cell density and self-renewal were maintained per unit tissue area with aging, but rates of inferred differentiation into Type I cells, and indeed overall density of Type I cells was reduced. Microarray analysis revealed age-related changes in multiple genes, including some with roles in proliferation and differentiation, and in IGF and TGFβ signalling pathways. By characterising how lung stem cell dynamics change with aging, this study will elucidate how they contribute to age-related loss of pulmonary function, and pathogenesis of common age-related pulmonary diseases.

A novel histone acetyltransferase inhibitor A485 improves sensitivity of non-small-cell lung carcinoma cells to TRAIL

Transcriptional coactivators p300 and CBP catalyze the acetylation of lysine residues in histone proteins. Upregulation of p300 and CBP has been associated with lung, colorectal and hepatocellular cancer, indicating an important role of p300 and CBP in tumorigenesis. Recently, the novel p300 and CBP-selective inhibitor A485 became available, which was shown to inhibit proliferation of 124 different cancer cell lines. Here, we found that downregulation of EP300 or CREBBP enhances apoptosis upon TRAIL stimulation in non-small-cell lung cancer (NSCLC) cells. A485 upregulates pro- and anti-apoptotic genes at the mRNA level, implying an apoptosis-modulating effect in NSCLC cells. However, A485 alone does not induce apoptosis. Interestingly, we observed that the number of apoptotic cells increases upon combined treatment with A485 and TRAIL. Therefore, A485, as a TRAIL-sensitizer, was used in combination with TRAIL in wild type of NSCLC cell lines (HCC827 and H1650) and cells with acquired erlotinib resistance (HCC827-ER and H1650-ER). Our results show that the combination of A485 and TRAIL synergistically increases cell death and inhibits long-term cell proliferation. Furthermore, this combination inhibits the growth of 3D spheroids of EGFR-TKI-resistant cells. Taken together, we demonstrate a successful combination of A485 and TRAIL in EGFR-TKI-sensitive and resistant NSCLC cells.

Cx32 mediates norepinephrine-promoted EGFR-TKI resistance in a gap junction-independent manner in non-small-cell lung cancer

The second-generation EGFR-TKI Afatinib is an irreversible ErbB family blocker used to treat patients with non-small-cell lung cancer (NSCLC). Unfortunately, resistance to this drug develops over time, and patients are always under great psychological pressure. A previous study showed that chronic stress hormones participate in EGFR-TKI resistance via β2 -AR signaling via an IL-6 dependent mechanism. Our study further explores a novel potential underlying mechanism. In the present study, we show that the stress hormone norepinephrine (NE) promotes Afatinib resistance by upregulating Cx32 expression. Furthermore, we, for the first time, find that Cx32 is a target gene for transcription factor CREB and NE enhances Cx32 mRNA expression by activation of CREB. We also demonstrate that Cx32 promotes Afatinib resistance by decreasing the degradation of EGFR-TKI resistance-associated proteins (MET, IGF-1R) and by increasing their transcription levels. Together, these results reveal that the stress hormone NE accelerates Afatinib resistance by increasing the expression of Cx32, which augments MET and IGF-1R levels in cancer cells and provides a promising therapeutic strategy against EGFR-TKI Afatinib resistance in NSCLC.

MiR-4458 inhibits breast cancer cell growth, migration, and invasiveness by targeting CPSF4

Numerous studies have reported that CPSF4 is over-expressed in a large percentage of human lung cancers, and CPSF4 has been identified as a potential oncogene of human lung tumor. Downregulation of CPSF4 inhibits the proliferation and promotes the apoptosis of lung adenocarcinoma cells. A previous study by our group also found overexpression of CPSF4 in breast cancer (BC), and was closely associated with a poor prognosis for the patient. This study investigates microRNAs (miRNAs) that target CPSF4 to modulate BC cell proliferation. We found that miR-4458 was noticeably reduced in BC tissues and cells. Using a miR-4458 mimic, we found that cell proliferation, migration, and invasiveness were suppressed by miR-4458 overexpression, and were enhanced by reducing the expression of miR-4458. Moreover, the results from bioinformatics analyses suggest a putative target site in the CPSF4 3'-UTR. Furthermore, using luciferase reporter assays and Western blotting, we verified that miR-4458 directly targets the 3'-UTR of CPSF4 and downregulates COX-2 and h-TERT, which are downstream target genes of CPSF4. Additionally, PI3K/AKT and ERK were shown to be inhibited by miR-4458 overexpression in BC cells. Moreover, miR-4458 suppresses BC cell growth in vivo. Consequently, these results suggest that the miR-4458-CPSF4-COX-2-hTERT axis might serve as a potential target for the treatment of BC patients.

Repression of GCN5 expression or activity attenuates c-MYC expression in non-small cell lung cancer

Lung cancer causes the highest mortality in cancer-related deaths. As these cancers often become resistant to existing therapies, definition of novel molecular targets is needed. Epigenetic modifiers may provide such targets. Recent reports suggest that the histone acetyltransferase (HAT) module within the transcriptional coactivator SAGA complex plays a role in cancer, creating a new link between epigenetic regulators and this disease. GCN5 serves as a coactivator for MYC target genes, and here we investigate links between GCN5 and c-MYC in non-small cell lung cancer (NSCLC). Our data indicate that both GCN5 and c-MYC proteins are upregulated in mouse and human NSCLC cells compared to normal lung epithelial cells. This trend is observable only at the protein level, indicating that this upregulation occurs post-transcriptionally. Human NSCLC tissue data provided by The Cancer Genome Atlas (TCGA) indicates that GCN5 and c-MYC expression are positively associated with one another and with the expression of c-MYC target genes. Depletion of GCN5 in NSCLC cells reduces c-MYC expression, cell proliferation, and increases the population of necrotic cells. Similarly, inhibition of the GCN5 catalytic site using a commercially available probe reduces c-MYC expression, cell proliferation, and increases the percentage of cells undergoing apoptosis. Our findings suggest that GCN5 might provide a novel target for inhibition of NSCLC growth and progression.

CPSF3 is a promising prognostic biomarker and predicts recurrence of non-small cell lung cancer

Cleavage polyadenylation specificity factor (CPSF) is the core component of the 3′-end processing complex, which determines the site of 3′-end cleavage interactions of specific sequence elements within pre-mRNAs. The present study revealed that all members of the CPSF complex were overexpressed in lung cancer tissue from The Cancer Genome Atlas (TCGA) Lung Cancer Cohort compared with normal lung tissue. Analysis of overall survival and recurrence-free survival verified that only CPSF3 was associated with prognosis and recurrence of lung adenocarcinoma (LUAD), and thus could be a promising biomarker. Additionally, receiver operating characteristic curve analysis revealed that CPSF3 may function as a diagnostic biomarker to distinguish between two histological subtypes of non-small cell lung cancer. Furthermore, analysis of the association of CPSF3 expression with clinicopathological parameters indicated that CPSF3 was associated with smoking history, tumor diameter, lymph node metastasis, clinical stage and radiation therapy in LUAD. Additionally, analysis of the DNA methylation data of the TCGA-LUAD Cohort revealed that CPSF3 DNA CpG sites (cg12057242 and cg25739938) were generally hypomethylated in LUAD compared with normal lung tissue. Correlation analysis identified the CPSF3 DNA CpG site cg25739938 to be negatively correlated with CPSF3 expression, while no correlation was identified with cg12057242. In addition, correlation analysis demonstrated that the overexpression of CPSF3 was correlated with CPSF3 DNA copy number variants (CNAs). The findings indicate that abnormal expression of CPSF3 may be caused by DNA CNAs; and DNA hypermethylation and function may be a promising diagnostic and prognostic indicator for LUAD.

Ovarian cancer-derived exosomes promote tumour metastasis in vivo: an effect modulated by the invasiveness capacity of their originating cells

Exosomes are small nanovesicles that carry bioactive molecules which can be delivered to neighbouring cells to modify their biological functions. Studies have showed that exosomes from ovarian cancer (OVCA) cells can alter the cell migration and proliferation of cells within the tumour microenvironment, an effect modulated by the invasiveness capacity of their originating cells. Using an OVCA cell line xenograph mouse model, we showed that exosomes derived from a high invasiveness capacity cell line (exo-SKOV-3) promoted metastasis in vivo compared with exosomes from a low invasiveness capacity cell line (exo-OVCAR-3). Analysis from anin vivo imaging system (IVIS) revealed that exo-SKOV-3 formed metastatic niches, whereas exo-OVCAR-3 formed colonies of clustered cells close to the site of injection. Interestingly, kinetic parameters showed that the half-maximal stimulatory time (ST₅₀) of tumour growth with exo-OVCAR-3 (4.0 ± 0.31 weeks) was significantly lower compared with the ST₅₀ in mice injected with exo-SKOV-3 (4.5 ± 0.32 weeks). However, the number of metastic nodes in mice injected with exo-SKOV-3 was higher compared with exo-OVCAR-3. Using a quantitative mass spectrometry approach (SWATH MS/MS) followed by bioinformatics analysis using the Ingenuity Pathway Analysis (IPA), we identified a total of 771 proteins. Furthermore, 40 of these proteins were differentially expressed in tumour tissues from mice injected with exo-SKOV-3 compared with exo-OVCAR-3, and associated with Wnt canonical pathway (β-catenin). Finally, we identified a set of proteins which had elevated expression in the circulating exosomes in association with tumour metastasis. These observations suggest that exosomal signalling plays an important role in OVCA metastasis.

A CRISPR Interference of CBP and p300 Selectively Induced Synthetic Lethality in Bladder Cancer Cells In Vitro

The transcriptional coactivator CREB-binding protein (CBP) and p300 are adenoviral E1A-binding proteins involved in various cellular processes, including embryonic development, homeostasis, cell differentiation and transcription activation. Previous study suggested that synthetic lethality between CBP and p300 inhibition in lung and hematopoietic cancers. However, the underlying mechanism of CBP and p300 paralog in bladder cancer remains unknown. In this study, we discovered that combined CBP and p300 inhibition impaired cell proliferation and induced apoptosis of bladder cancer cells and normal bladder urothelial cell via decreasing c-Myc expression. Then, we employed the dCas9-KRAB system, hTERT promoter and hUPII promoter to construct an CRISPR interference system which could specifically repress CBP and p300 expression and cause lethality in bladder cancer cells in vitro. The CRISPR interference system we constructed could specifically inhibit the progression of bladder cancer, providing a novel strategy to fight against bladder cancer.

lncRNA PLAC2 activated by H3K27 acetylation promotes cell proliferation and invasion via the activation of Wnt/β‑catenin pathway in oral squamous cell carcinoma

As a new group of important effector molecules involved in multiple cancer types, including breast cancer, lung cancer and oral squamous cell carcinoma, long noncoding RNAs (lncRNAs) have attracted considerable attention recently. However, the underlying cause that induces the dysregulated lncRNAs in cancer remains poorly understood. In the present study, the regulatory model of the lncRNA placenta-specific protein 2 (PLAC2) upregulation in oral squamous cell carcinoma (OSCC) was investigated and its biological functions in OSCC malignant progression was identified. A reverse transcription-quantitative polymerase chain reaction assay identified that PLAC2 is upregulated in OSCC cell lines and primary tissue samples. Furthermore, bioinformatic analysis followed by chromatin immunoprecipitation verified an enriched histone H3 on lysine 27 (H3K27) acetylation (H3K27ac) at the promoter region of the PLAC2 gene. Knockdown of cAMP-response element binding protein-binding protein (CBP) significantly reduced the enrichment level of H3K27ac, and thereby induced a decreased expression of PLAC2. Functionally, overexpression of PLAC2 promotes OSCC cell proliferation, migration and invasion, whereas knockdown of PLAC2 exerted an opposite effect. Furthermore, the Wnt/β-catenin signaling pathway was activated by PLAC2 and mediated the PLAC2-induced malignant progress of OSCC. In conclusion, the present results indicated that lncRNA PLAC2 is transcriptionally activated by H3K27ac modification at the promoter region in OSCC, and promotes cell growth and metastasis via activating Wnt/β-catenin signaling pathway. Therefore, PLAC2 may serve as a promising biomarker for OSCC prognosis and therapy.

Epigenetic modifications promote the expression of the orphan nuclear receptor NR0B1 in human lung adenocarcinoma cells

The ectopic activation of NR0B1 is involved in the development of some cancers. However, the regulatory mechanisms controlling NR0B1 expression are not well understood. Therefore, the epigenetic modifications promoting NR0B1 activation were examined in this study. NR0B1 protein was detected in cancerous tissues of more than 50% of human lung adenocarcinoma (ADCA) cases and tended to be expressed in low-differentiated cancerous tissues obtained from males. Nevertheless, NR0B1 activation in ADCA has not previously been correlated with DNA demethylation. NR0B1 expression was not detected in 293T cells, although it contains a hypomethylated NR0B1 promoter. Treating 293T cells with a histone deacetylase inhibitor increased acetylated histone H4 binding to the NR0B1 promoter and activated NR0B1 expression. In contrast, treatment with histone methylase inhibitors decreased the methylation of histones H3K9 and H3K27 and slightly induced NR0B1 transcription. Furthermore, the level of acetyl-histone H4 binding to the NR0B1 promoter increased, whereas the occupancy of H3K27me3 was lower in cancerous tissues than in non-cancerous tissues. Similar histone occupancies were confirmed in a comparison of cancerous tissues with strong, moderate and negative NR0B1 expression. In conclusion, this study shows that CpG methylation within the NR0B1 promoter is not involved in the in vivo regulation of NR0B1 expression, whereas the hyperacetylation of histone H4 and the unmethylation of histones H3K9 and H3K27, and their binding to the NR0B1 promoter results in decondensed euchromatin for NR0B1 activation.

A folylpoly-γ-glutamate synthase single nucleotide polymorphism associated with response to pemetrexed treatment combined with platinum for non-small cell lung cancer

OBJECTIVES

In this study, we investigated whether single nucleotide polymorphisms (SNPs) in folylpoly-γ-glutamate synthase (FPGS), which catalyzes the polyglutamation of pemetrexed (PEM), is related to FPGS expression and the response to PEM in non-small cell lung cancer (NSCLC).

MATERIALS AND METHODS

We first examined FPGS protein expressions according to FPGS SNPs genotype groups in 15 lung adenocarcinoma cell lines. Next, 101 non-squamous NSCLC patients treated with PEM and platinum drugs were classified into FPGS SNP genotype groups to investigate the relation between FPGS SNP genotypes and treatment outcome.

RESULTS

When the 15 adenocarcinoma cell lines were classified into FPGS SNP 2572C>T genotype groups, we found that the FPGS protein expression was significantly higher in the CC genotype group than in the TT+CT genotype group (p=0.0022). In contrast, there was no significant difference in FPGS expression when another FPGS SNP was analyzed. We also examined the FPGS SNP 2572C>T genotype in 101 non-squamous NSCLC patients treated with PEM and platinum drugs. Among these 101 patients, response rate was significantly higher in the CC genotype group than in the TT+CT genotype group (p=0.0034). When we examined the patients treated with PEM, platinum drugs and Bev, almost all (29/33) were classified into the TT+CT genotype group. The response rate, progression-free survival, and over-all survival were all significantly better in the patients of the TT+CT genotype group who also received Bev than in those who did not receive Bev (p=0.034, 0.021, 0.018, respectively).

CONCLUSION

FPGS SNP 2572C>T is a predictive marker of the efficacy of PEM and platinum drugs for NSCLC.

CREB-binding protein regulates lung cancer growth by targeting MAPK and CPSF4 signaling pathway

CBP (CREB-binding protein) is a transcriptional co-activator which possesses HAT (histone acetyltransferases) activity and participates in many biological processes, including embryonic development, growth control and homeostasis. However, its roles and the underlying mechanisms in the regulation of carcinogenesis and tumor development remain largely unknown. Here we investigated the molecular mechanisms and potential targets of CBP involved in tumor growth and survival in lung cancer cells. Elevated expression of CBP was detected in lung cancer cells and tumor tissues compared to the normal lung cells and tissues. Knockdown of CBP by siRNA or inhibition of its HAT activity using specific chemical inhibitor effectively suppressed cell proliferation, migration and colony formation and induced apoptosis in lung cancer cells by inhibiting MAPK and activating cytochrome C/caspase-dependent signaling pathways. Co-immunoprecipitation and immunofluorescence analyses revealed the co-localization and interaction between CBP and CPSF4 (cleavage and polyadenylation specific factor 4) proteins in lung cancer cells. Knockdown of CPSF4 inhibited hTERT transcription and cell growth induced by CBP, and vice versa, demonstrating the synergetic effect of CBP and CPSF4 in the regulation of lung cancer cell growth and survival. Moreover, we found that high expression of both CBP and CPSF4 predicted a poor prognosis in the patients with lung adenocarcinomas. Collectively, our results indicate that CBP regulates lung cancer growth by targeting MAPK and CPSF4 signaling pathways.