NAP1L1 Functions as a Tumor Promoter via Recruiting Hepatoma-Derived Growth Factor/c-Jun Signal in Hepatocellular Carcinoma

CircDCAF8 promotes the progression of hepatocellular carcinoma through miR-217/NAP1L1 Axis, and induces angiogenesis and regorafenib resistance via exosome-mediated transfer

BACKGROUND

Circular RNAs (circRNAs), which are a new type of single-stranded circular RNA, have significant involvement in progression of many diseases, including tumors. Currently, multiple circRNAs have been identified in hepatocellular carcinoma (HCC). Our study aims to investigate the function and mechanism of circDCAF8 in HCC.

METHODS

The expression of circDCAF8 (hsa_circ_0014879) in HCC and para-carcinoma tissue samples was determined using quantitative real-time polymerase chain reaction (qRT-PCR). The biological function of circDCAF8 in HCC was confirmed by experiments conducted both in vitro and in vivo. And the relationship between circDCAF8, miR-217 and NAP1L1 was predicted by database and verified using qRT-PCR, RNA-binding protein immunoprecipitation (RIP) and dual-luciferase reporter assays. Exosomes isolated from HCC cells were utilized to assess the connection of exosomal circDCAF8 with HCC angiogenesis and regorafenib resistance.

RESULTS

CircDCAF8 is upregulated in HCC tissues and cell lines, and is linked to an unfavourable prognosis for HCC patients. Functionally, circDCAF8 was proved to facilitate proliferation, migration, invasion and Epithelial-Mesenchymal Transformation (EMT) in HCC cells. Animal examinations also validated the tumor-promoting characteristics of circDCAF8 on HCC. Besides, exosomal circDCAF8 promoted angiogenesis in HUVECs. Mechanistically, circDCAF8 interacted with miR-217 and NAP1L1 was a downstream protein of miR-217. CircDCAF8 promoted NAP1L1 expression by sponging miR-217. In addition, exosomes may transfer circDCAF8 from regorafenib-resistant HCC cells to sensitive cells, where it would confer a resistant phenotype.

CONCLUSION

CircDCAF8 facilitates HCC proliferation and metastasis via the miR-217/NAP1L1 axis. Meanwhile, circDCAF8 can promote angiogenesis and drive resistance to regorafenib, making it a viable therapeutic target for HCC patients.

SP2-induced circPUM1 modulates chemoresistance and nature killer cell toxicity in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is a type of tumour found in the cavity that is characterized by differentiation and metastasis to the lymph nodes. Although diagnosis strategy and clinical treatment have recently improved, the outcomes for OSCC patients remain unsatisfactory. This study verified the characteristics of circPUM1 in OSCC cells, subsequently generating dysregulated circPUM1 cell models, showing that circPUM1 promoted chemoresistance and natural killer (NK) cell toxicity. Furthermore, the transcription factor SP2 regulated the expression of circPUM1 in OSCC cells, circPUM1 acted as a molecular sponge for miR-770-5p. Moreover, Nucleosome Assembly Protein 1 Like 1 (NAP1L1) is a downstream target for miR-770-5p and essential for circPUM1-mediated cisplatin resistance and NK cell cytotoxicity in OSCC cells. The network composed of SP2, circPUM1, miR-770-5p and NAP1L1 in OSCC appears to be a promising avenue for the development of novel targets for diagnosing or treating OSCC.

Benefit of using interaction effects for the analysis of high-dimensional time-response or dose-response data for two-group comparisons

High throughput RNA sequencing experiments are widely conducted and analyzed to identify differentially expressed genes (DEGs). The statistical models calculated for this task are often not clear to practitioners, and analyses may not be optimally tailored to the research hypothesis. Often, interaction effects (IEs) are the mathematical equivalent of the biological research question but are not considered for different reasons. We fill this gap by explaining and presenting the potential benefit of IEs in the search for DEGs using RNA-Seq data of mice that receive different diets for different time periods. Using an IE model leads to a smaller, but likely more biologically informative set of DEGs compared to a common approach that avoids the calculation of IEs.

Nucleosome assembly protein 1 like 1 (NAP1L1) promotes cardiac fibrosis by inhibiting YAP1 ubiquitination and degradation

Myocardial fibrosis post myocardial infarction (MI) is characterized by abnormal extracellular matrix (ECM) deposition and cardiac dysfunction could finally develop into serious heart disease, like heart failure. Lots of regulating factors involved in this pathological process have been reported while the specific mediators and underlying mechanisms remain to need to be further investigated. As part of the NAP1 family, Nucleosome assembly protein 1 like 1 (NAP1L1) is expressed in a wide variety of tissues. Here, we report that NAP1L1 is a significant regulator of cardiac fibrosis and is upregulated in ischemic cardiomyopathy patient hearts. Enhanced expression of NAP1L1 can promote cardiac fibroblasts (CFs) proliferation, migration, and differentiation into myofibroblasts. In contrast, loss of NAP1L1 decreased fibrosis-related mRNA and protein levels, inhibited the trans-differentiation, and blunted migration and proliferation of CFs after Transforming Growth Factorβ1（TGF-β1）stimulation. In vivo, NAP1L1 knockout mice enhanced cardiac function and reduced fibrosis area in response to MI stimuli. Mechanically, NAP1L1 binding to Yes-associated protein 1 (YAP1) protein influences its stability, and silencing NAP1L1 can inhibit YAP1 expression by promoting its ubiquitination and degradation in CFs. Collectively, NAP1L1 could potentially be a new therapeutic target for various cardiac disorders, including myocardial fibrosis.

NAP1L1 is a novel microtubule-associated protein

Microtubule-associated proteins (MAPs) regulate assembly and stability of microtubules (MTs) during cell cytokinesis, cell migration, neuronal growth, axon guidance, and synapse formation. Using data mining of the Human Protein Atlas database and experimental screening, we identified nucleosome assembly protein 1 like 1 (NAP1L1) as a new MAP. The Human Protein Atlas and PubMed database screening identified 99 potential new MAPs. Twenty candidate proteins that highly co-localized with MTs were exogenously expressed with green fluorescent protein (GFP) or hemagglutinin (HA) tags in tissue culture cells and MTs were co-stained for immunofluorescent microscopy. We found that NAP1L1 is mainly localized in the cytosol with MTs during interphase. Using bacterially expressed recombinant NAP1L1 fragments and purified MTs, we biochemically mapped the MT-binding site on the N-terminal region (1-72aa) and the central region (164-269aa) of NAP1L1. NAP1L1 dimerizes through the long helix region (73-163aa), and full-length NAP1L1 induces the formation of thick MTs, indicating that NAP1L1 has the ability to bundle MTs in cells. Analysis of publicly available RNA-seq data of NAP1L1 depleted cells suggested that NAP1L1 is involved in cell adhesion and migration in agreement with the function of NAP1L1 as a MAP.

Histone Chaperones and Digestive Cancer: A Review of the Literature

BACKGROUND

The global burden of digestive cancer is expected to increase. Therefore, crucial for the prognosis of patients with these tumors is to identify early diagnostic markers or novel therapeutic targets. There is accumulating evidence connecting histone chaperones to the pathogenesis of digestive cancer. Histone chaperones are now broadly defined as a class of proteins that bind histones and regulate nucleosome assembly. Recent studies have demonstrated that multiple histone chaperones are aberrantly expressed and have distinct roles in digestive cancers.

OBJECTIVE

The purpose of this review is to present the current evidence regarding the role of histone chaperones in digestive cancer, particularly their mechanism in the development and progression of esophageal, gastric, liver, pancreatic, and colorectal cancers. In addition, the prognostic significance of particular histone chaperones in patients with digestive cancer is discussed.

METHODS

According to PRISMA guidelines, we searched the PubMed, Embase, and MEDLINE databases to identify studies on histone chaperones and digestive cancer from inception until June 2022.

RESULTS

A total of 104 studies involving 21 histone chaperones were retrieved.

CONCLUSIONS

This review confirms the roles and mechanisms of selected histone chaperones in digestive cancer and suggests their significance as potential prognostic biomarkers and therapeutic targets. However, due to their non-specificity, more research on histone chaperones should be conducted in the future to elucidate novel strategies of histone chaperones for prognosis and treatment of digestive cancer.

NAP1L1 Functions as a Novel Prognostic Biomarker Associated With Macrophages and Promotes Tumor Progression by Influencing the Wnt/β-Catenin Pathway in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is regarded as one of the universal cancers in the world. Therefore, our study is based on clinical, molecular mechanism and immunological perspectives to analyze how NAP1L1 affects the progression of HCC. To begin with, the gene expression datasets and clinical data of GSE14520, GSE76427, ICGC, and TCGA are originated from GEO, ICGC, and TCGA databases. Subsequently, DEG screening was performed on data using R studio, and we finally found that 2,145 overlapping DEGs were screened from four datasets at the end. Then, we used R studio to filter the survival-related genes of the GSE76427 and ICGC datasets, and we screened out 101 survival-related genes. Finally, 33 common genes were screened out from 2,145 overlapping DEGs and 101 survival-related genes. Then, NAP1L1 was screened from 33 common genes using the CytoHubba plug-in in Cytoscape software. Furthermore, ground on GEO, ICGC, and TCGA databases, the survival analysis, clinical feature analysis, univariate/multivariate regression analysis, and multiple GSEA were used to study NAP1L1. The Conclusion claimed that HCC patients with higher expression levels of NAP1L1 had a poorer prognosis than those with lower expression levels. Thus, we believe that NAP1L1 is an independent prognostic factor for HCC. In order to shed light on NAP1L1’s molecular mechanism promoting the progression of HCC closely, the GSEA tool was applied to complete the GSEA of the four datasets. Furthermore, the results confirmed that NAP1L1 could promote HCC progression by regulating the G2/M transition of the cell cycle and Wnt signaling pathway. Western blot and flow cytometry were also performed to understand those mechanisms in this study. The result of Western blot showed that NAP1L1 silencing led to downregulation of CDK1 and β-catenin proteins; the result of flow cytometry showed that cell numbers in the G2 phase were significantly increased when NAP1L1 was silenced. Thus, we claimed that NAP1L1 might promote HCC progression by activating the Wnt signaling pathway and promoting cell cycle G2/M transition. In addition, ground on GSE14520 and GSE76427 datasets, and ICGC and TCGA databases, the correlation between NAP1L1 and immune cells was analyzed in HCC patients. At the same time, the TISIDB online database and the TIMER online database were testified to the association between NAP1L1 and immune cells. Hence, the summary shows that NAP1L1 was connected with a certain amount of immune cells. We can speculate that NAP1L1 may influence macrophages to promote HCC progression through some potential mechanisms.

NAP1L5 Promotes Nucleolar Hypertrophy and Is Required for Translation Activation During Cardiomyocyte Hypertrophy

Pathological growth of cardiomyocytes during hypertrophy is characterized by excess protein synthesis; however, the regulatory mechanism remains largely unknown. Using a neonatal rat ventricular myocytes (NRVMs) model, here we find that the expression of nucleosome assembly protein 1 like 5 (Nap1l5) is upregulated in phenylephrine (PE)-induced hypertrophy. Knockdown of Nap1l5 expression by siRNA significantly blocks cell size enlargement and pathological gene induction after PE treatment. In contrast, Adenovirus-mediated Nap1l5 overexpression significantly aggravates the pro-hypertrophic effects of PE on NRVMs. RNA-seq analysis reveals that Nap1l5 knockdown reverses the pro-hypertrophic transcriptome reprogramming after PE treatment. Whereas, immune response is dominantly enriched in the upregulated genes, oxidative phosphorylation, cardiac muscle contraction and ribosome-related pathways are remarkably enriched in the down-regulated genes. Although Nap1l5-mediated gene regulation is correlated with PRC2 and PRC1, Nap1l5 does not directly alter the levels of global histone methylations at K4, K9, K27 or K36. However, puromycin incorporation assay shows that Nap1l5 is both necessary and sufficient to promote protein synthesis in cardiomyocyte hypertrophy. This is attributable to a direct regulation of nucleolus hypertrophy and subsequent ribosome assembly. Our findings demonstrate a previously unrecognized role of Nap1l5 in translation control during cardiac hypertrophy.