NKAP alters tumor immune microenvironment and promotes glioma growth via Notch1 signaling

NKAP: A new m6A RNA binding protein predicts prognosis and immunotherapy response in head and neck squamous cell carcinoma

OBJECTIVE

This study aimed to investigate whether NKAP (nuclear factor κB activating protein) serves as a prognostic marker and predictive biomarker for immunotherapy response in head and neck squamous cell carcinoma (HNSCC).

METHODS

A retrospective cohort study combined with in vitro analyses was conducted. NKAP mRNA expression levels were assessed in 520 HNSCC tumor tissues and 44 normal tissues from the TCGA dataset and validated in a clinical cohort (n = 32). Clinical correlations with overall survival and immunotherapy outcomes were analyzed. The key pathological variables included tumor stage, grade, HPV status, and TP53 mutation. Appropriate statistics were calculated at a significant level (P<0.05).

RESULTS

In this study, we have collected tissue samples from HNSCC patients (mean age: 52.65 ± 7.76; males 66%, females 34%). NKAP was upregulated in HNSCC tissues compared to adjacent normal tissues (P < 0.001). The high expression of NKAP correlated with advanced tumor stage, grade, and reduced survival (P < 0.05). High expression levels of NKAP were also associated with anti-PD-L1 therapy response (P < 0.05). Functional enrichment analysis revealed NKAP involvement in cell cycle regulation, mRNA processing, and chromatin remodeling pathways critical for cancer progression.

CONCLUSION

NKAP represents a promising prognostic marker and therapeutic target for immunotherapy in HNSCC. Prospective studies are warranted to confirm these findings.

Capn3b-deficient zebrafish model reveals a key role of autoimmune response in LGMDR1

Mutations in calcium-dependent papain-like protease CALPAIN3 (CAPN3) cause Limb-Girdle Muscular Dystrophy Recessive Type 1 (LGMDR1), the most common limb-girdle muscular dystrophy in humans. In addition to progressive muscle weakness, persistent inflammatory infiltration is also a feature of LGMDR1. Despite the underlying mechanism remaining poorly understood, we consider that it may relate to the newly defined role of CAPN3/Capn3b in the nucleolus. Here, we report that the loss of function of zebrafish capn3b, the counterpart of human CAPN3, induces an autoimmune response akin to that in LGMDR1 patients. capn3b mutant larvae are more susceptible to Listeria monocytogenes injection, characterized by recruiting more macrophages. Under germ-free conditions, transcriptome analysis of the capn3b mutant muscle reveals a significant upregulation of the chemokine-production-related genes. Coincidently, more neutrophils are recruited to the injury site imposed by either muscle stabbing or tail fin amputation. Nucleolar proteomic analysis and enzymatic assays reveal NKAP, an activating factor of the NF-κB pathway, to be a target of CAPN3. We conclude that the accumulation of Nkap and other factors in the capn3b mutant may be involved in the over-activation of innate immunity. Our studies indicate that the zebrafish capn3b mutant is a powerful model for studying the immunity-related progression of human LGMDR1.

Notch signaling pathway in cancer: from mechanistic insights to targeted therapies

Notch signaling, renowned for its role in regulating cell fate, organ development, and tissue homeostasis across metazoans, is highly conserved throughout evolution. The Notch receptor and its ligands are transmembrane proteins containing epidermal growth factor-like repeat sequences, typically necessitating receptor-ligand interaction to initiate classical Notch signaling transduction. Accumulating evidence indicates that the Notch signaling pathway serves as both an oncogenic factor and a tumor suppressor in various cancer types. Dysregulation of this pathway promotes epithelial-mesenchymal transition and angiogenesis in malignancies, closely linked to cancer proliferation, invasion, and metastasis. Furthermore, the Notch signaling pathway contributes to maintaining stem-like properties in cancer cells, thereby enhancing cancer invasiveness. The regulatory role of the Notch signaling pathway in cancer metabolic reprogramming and the tumor microenvironment suggests its pivotal involvement in balancing oncogenic and tumor suppressive effects. Moreover, the Notch signaling pathway is implicated in conferring chemoresistance to tumor cells. Therefore, a comprehensive understanding of these biological processes is crucial for developing innovative therapeutic strategies targeting Notch signaling. This review focuses on the research progress of the Notch signaling pathway in cancers, providing in-depth insights into the potential mechanisms of Notch signaling regulation in the occurrence and progression of cancer. Additionally, the review summarizes pharmaceutical clinical trials targeting Notch signaling for cancer therapy, aiming to offer new insights into therapeutic strategies for human malignancies.

Cancer-associated fibroblasts-induced remodeling of tumor immune microenvironment via Jagged1 in glioma

Tumor immunosuppression are prominent characteristics of brain glioma. Current standard modality including surgical resection and chemoradiotherapy do not significantly improve clinical outcomes. Cancer-associated fibroblasts (CAFs) that regard as important stromal cells in tumor microenvironment have been confirmed to play crucial roles in tumor development. However, the effects of CAFs on tumor immunosuppression in glioma are not well expounded. In this study, we report that CAFs contributes to the formation of glioma immunosuppressive microenvironment. Specifically, we found that glioma-derived Jagged1 enhanced the proliferation and PD-L1 expression of CAFs in vitro. Importantly, we discovered that Notch1, c-Myc and PD-L1 expression were significantly increased in high Jagged1-expressing gliomas, moreover, we further confirmed that Notch1 and PD-L1 expression located on the CAFs in glioma tissues. We also found that glioma-derived Jagged1 promotes the increase of tumor-infiltrating macrophages, M2 macrophages and Foxp3 Treg cells, as well as no significance of M1 macrophages and CD8+ T cells, indicating potential immunosuppression. This study opens up novel therapeutic strategies reversing CAF immunosuppression for gliomas.

TBC1D1 represses glioma progression by altering the integrity of the cytoskeleton

BACKGROUND

Glioma is one of the most aggressive malignant brain tumors and is characterized by invasive growth and poor prognosis. TBC1D1, a member of the TBC family, is associated with the development of various malignancies. However, the role of TBC1D1 in glioma-genesis remains unclear.

METHODS

The effect of TBC1D1 on the prognosis of glioma patients and related influencing factors were analyzed in the Chinese Glioma Genome Atlas (CGGA) and The Cancer Genome Atlas (TCGA) databases. Expression of TBC1D1 in glioma cell lines was detected by western blotting. Cell viability and proliferation were measured by EdU and Colony formation assays, respectively. Transwell and wound healing assays were performed to determine the cell migration and invasion capacities. Immunofluorescence was used to observe actin morphology in the cytoskeleton.

RESULTS

We discovered that high TBC1D1 expression in gliomas led to poor prognosis. Downregulation of TBC1D1 in glioma cells significantly inhibited multiple important functions, such as proliferation, migration, and invasion. We further demonstrated that the tumor-inhibitory effect of TBC1D1 might occur through the P-LIMK/cofilin pathway, destroying the cytoskeletal structure and affecting the depolymerization of F-actin, thereby inhibiting glioma migration.

CONCLUSION

TBC1D1 affects the balance and integrity of the actin cytoskeleton via cofilin, thereby altering the morphology and aggressiveness of glioma cells. This study provides a new perspective on its role in tumorigenesis, thereby identifying a potential therapeutic target for the treatment of gliomas.

Knockdown of NF-κB activating protein promotes pancreatic cancer growth and metastasis through mTOR signaling pathway

BACKGROUND

NF-κB activating protein (NKAP) acts as a transcriptional suppressor in the Notch signaling pathway, It plays a role in hematopoiesis maintenance, immune cell development, maturation, and functional competency acquisition. NKAP has been found to act as an oncogene in many tumors, but it has not been reported in PAAD.The purpose of this study was to investigate the effect of NKAP on the growth and metastasis of pancreatic adenocarcinoma(PAAD).

METHODS AND RESULTS

In this study, western blot and qRT-PCR showed that highly expressed NKAP was found in PAAD cell lines, and small interfering RNA (siRNA) was employed to reduce the expression of NKAP in PAAD cell lines. The results of CCK-8, clony formation, Transwell and flow cytometry showed that knockdown of NKAP significantly inhibited biological function of PAAD cells, and increased cell apoptosis. Study also observed that knockdown of NKAP inhibited the expression levels of apoptosis proteins and cyclin in PAAD cells. In addition, mTOR's degree of phosphorylation and the expression of its downstream target p70S6K can both be activated by NKAP. This effect was also confirmed in salvage experiments performed with Rapamycin(RaPa), an inhibitor of mTOR. At the end of the experiment, It was investigated how NKAP affected the drug sensitivity of gemcitabine used to treat PAAD. The results showed that knocking down NKAP could increase the drug sensitivity of gemcitabine.

CONCLUSIONS

NKAP as an oncogene regulates the development of PAAD cells. The research found that the mTOR signaling pathway is engaged in the oncogenic role of NKAP in PAAD for the first time.

Targeting Options of Tumor-Associated Macrophages (TAM) Activity in Gliomas

Tumor-associated macrophages (TAMs), the most plastic cells of the hematopoietic system, exhibit increased tumor-infiltrating properties and functional heterogeneity depending on tumor type and associated microenvironment. TAMs constitute a major cell type of cancer-related inflammation, commonly enhancing tumor growth. They are profoundly involved in glioma pathogenesis, contributing to many cancer hallmarks such as angiogenesis, survival, metastasis, and immunosuppression. Efficient targeting of TAMs presents a promising approach to tackle glioma progression. Several targeting options involve chemokine signaling axes inhibitors and antibodies, antiangiogenic factors, immunomodulatory molecules, surface immunoglobulins blockers, receptor and transcription factor inhibitors, as well as microRNAs (miRNAs), administered either as standalone or in combination with other conventional therapies. Herein, we provide a critical overview of current therapeutic approaches targeting TAMs in gliomas with the promising outcome.

Exosomal circPRRX1 functions as a ceRNA for miR-596 to promote the proliferation, migration, invasion, and reduce radiation sensitivity of gastric cancer cells via the upregulation of NF-κB activating protein

Exosomes, which are small extracellular vesicles, have been unveiled to carry circular RNAs (circRNAs). CircRNA paired-related homeobox 1 (circPRRX1) can be transferred by exosomes derived from gastric cancer cells. Here, we investigated the activity and mechanism of exosomal circPRRX1 in gastric tumorigenesis and radiation sensitivity. CircPRRX1, microRNA (miR)-596, and NF-κB activating protein (NKAP) were quantified by quantitative real-time PCR and immunoblotting. Cell proliferation, motility, and invasion were detected by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and transwell assays, respectively. Cell colony formation and survival were assessed by colony formation assays. Dual-luciferase reporter assays were performed to verify the direct relationship between miR-596 and circPRRX1 or NKAP. In-vivo xenograft studies were used to evaluate the role of exosomal circPRRX1 in tumor growth. Our data showed that circPRRX1 expression was elevated in human gastric cancer, and circPRRX1 could be transferred by exosomes from gastric cancer cells. Exosomal circPRRX1 affected cell proliferation, motility, invasion, and radiation sensitivity in vitro and tumor growth in vivo. Mechanistically, circPRRX1 directly regulated miR-596 expression, and exosomal circPRRX1 affected cell biological functions at least in part through miR-596. NKAP was identified as a direct target and functionally downstream effector of miR-596. Exosomal circPRRX1 modulated NKAP expression by acting as a competing endogenous RNA (ceRNA) for miR-596. Our findings suggest a new mechanism, the exosomal circPRRX1/miR-596/NKAP ceRNA crosstalk, in regulating gastric tumorigenesis and radiation sensitivity.

miR-30c plays diagnostic and prognostic roles and mediates epithelial-mesenchymal transition (EMT) and proliferation of gliomas by affecting Notch1

miR-30c functions as a tumor suppressor gene in the majority of tumors, including gliomas. In our study, we discovered that the expression levels of miR-30c in glioma tissues and plasma prior to surgery were lower than those in normal brain tissue following brain injury decompression and in plasma in healthy volunteers. The low expression of miR-30c was closely aligned with the WHO grade, tumor size, PFS, and OS. Additionally, the miR-30c expression level in tumor tissue was positively correlated with the levels in preoperative plasma. In cell biology experiments, miR-30c inhibited EMT and proliferation, migration, and invasion of glioma cells. Analysis of databases of miRNA target genes, real-time quantitative PCR, western blotting, and dual luciferase reporter assays demonstrated that Notch1 is the direct target gene of miR-30c. An inhibitor and shRNA-Notch1 were cotransfected into glioma cells, and it was found that shRNA-Notch1 reduced the enhancement of inhibitors of EMT and proliferation, migration, and invasion of glioma cells. Therefore, we believe that when utilized as a tumor suppressor gene, miR-30c can inhibit EMT and the proliferation, migration, and invasion of glioma cells by directly acting on Notch1 at the posttranscriptional level and that it is a potential diagnostic and prognostic marker.

Discovery of Notch Pathway-Related Genes for Predicting Prognosis and Tumor Microenvironment Status in Bladder Cancer

Background: Notch signaling is a key regulator of immune cell differentiation and linked to autoimmune diseases, tumorigenesis and tumor-induced immunomodulation. An abnormally activated Notch signaling pathway contributes to almost all of the key features of cancer, including tumor angiogenesis, stemness, and epithelial-mesenchymal transition. Consequently, we investigated Notch pathway-related genes for developing prognostic marker and assessing immune status in bladder cancer.

Methods: The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases were utilized to analyze RNA-seq data for bladder cancer. Cluster subtypes were identified using the NMF algorithm. In order to establish a prognostic risk signature, the least absolute shrinkage and selection operator (Lasso) and Cox regression analysis was utilized. GSEA was carried out to investigate the molecular mechanisms. Immune cell infiltration levels in bladder cancer were calculated using the CIBERSORT algorithm. External clinical tissue samples were used to validate the expression levels of signature genes.

Results: Based on the NMF algorithm, bladder cancer samples were divided into two cluster subtypes and displayed different survival outcome and immune microenvironment. A six-gene risk signature (DTX3L, CNTN1, ENO1, GATA3, MAGEA1, and SORBS2) was independent for prognosis and showed good stability. The infiltration of immune cells and clinical variables were significantly different among the risk groups of patients. Response to immunotherapy also differed between different risk groups. Furthermore, the mRNA expression levels of the signature genes were verified in tissue samples by qRT-PCR.

Conclusion: We established a 6-gene signature associated with Notch pathway in bladder cancer to effectively predict prognosis and reflect immune microenvironment status.

Identification and Validation of N6-Methyladenosine-Related Biomarkers for Bladder Cancer: Implications for Immunotherapy

N6-methyladenosine (m⁶A) has emerged as one of the most important modifications of RNA. Based on the expression of 23 different modes of m⁶A regulatory factors, we identified three different m⁶A modification patterns in bladder cancer. The effects of the three different modes of m⁶A modification on clinicopathological characteristics, immune cell infiltration levels and expression levels of immune checkpoint genes were comprehensively analyzed. In addition, the effects of different modes of m⁶A modification on the therapeutic efficacy of anti-PD-L1 immunotherapy (atezolizumab) are also discussed. Our results confirm that m⁶A methylation plays an important role in immune cell recruitment in the tumor microenvironment of bladder cancer, which influences the efficacy of anti-PD-L1 therapy for bladder cancer. We further confirmed the important role of FTO protein in the biological function of bladder cancer cells by performing in vitro experiments. FTO functions as an oncogene in bladder cancer cells, and upon FTO knockdown, the level of m⁶A enzyme activity in bladder cancer cells was significantly increased, apoptosis was increased, and cell proliferation and cell invasion were reduced. In addition, our study also confirmed that K216H and K216E are probably important targets for regulating FTO. We provide new insights into the regulatory pathways of the immune microenvironment and the methylation function of m⁶A in bladder cancer, which will help in designing novel diagnostic methods, prognostic tools, and therapeutic targets.

Molecular Pathogenesis of Glioblastoma in Adults and Future Perspectives: A Systematic Review

Glioblastoma (GBM) is the most common and malignant tumour of the central nervous system. Recent appreciation of the heterogeneity amongst these tumours not only changed the WHO classification approach, but also created the need for developing novel and personalised therapies. This systematic review aims to highlight recent advancements in understanding the molecular pathogenesis of the GBM and discuss related novel treatment targets. A systematic search of the literature in the PubMed library was performed following the PRISMA guidelines for molecular pathogenesis and therapeutic advances. Original and meta-analyses studies from the last ten years were reviewed using pre-determined search terms. The results included articles relevant to GBM development focusing on the aberrancy in cell signaling pathways and intracellular events. Theragnostic targets and vaccination to treat GBM were also explored. The molecular pathophysiology of GBM is complex. Our systematic review suggests targeting therapy at the stemness, p53 mediated pathways and immune modulation. Exciting novel immune therapy involving dendritic cell vaccines, B-cell vaccines and viral vectors may be the future of treating GBM.

RNA binding protein NKAP protects glioblastoma cells from ferroptosis by promoting SLC7A11 mRNA splicing in an m6A-dependent manner

Ferroptosis is a form of cell death characterized by lipid peroxidation. Previous studies have reported that knockout of NF-κB activating protein (NKAP), an RNA-binding protein, increased lipid peroxidation level in naive T cells and induced cell death in colon cancer cells. However, there was no literature reported the relationship between NKAP and ferroptosis in glioblastoma cells. Notably, the mechanism of NKAP modulating ferroptosis is still unknown. Here, we found NKAP knockdown induced cell death in glioblastoma cells. Silencing NKAP increased the cell sensitivity to ferroptosis inducers both in vitro and in vivo. Exogenous overexpression of NKAP promoted cell resistance to ferroptosis inducers by positively regulating a ferroptosis defense protein, namely cystine/glutamate antiporter (SLC7A11). The regulation of SLC7A11 by NKAP can be weakened by the m⁶A methylation inhibitor cycloleucine and knockdown of the m⁶A writer METTL3. NKAP combined the “RGAC” motif which was exactly in line with the m⁶A motif “RGACH” (R = A/G, H = A/U/C) uncovered by the m⁶A-sequence. RNA Immunoprecipitation (RIP) and Co-Immunoprecipitation (Co-IP) proved the interaction between NKAP and m⁶A on SLC7A11 transcript. Following its binding to m⁶A, NKAP recruited the splicing factor proline and glutamine-rich (SFPQ) to recognize the splice site and then conducted transcription termination site (TTS) splicing event on SLC7A11 transcript and the retention of the last exon, screened by RNA-sequence and Mass Spectrometry (MS). In conclusion, NKAP acted as a new ferroptosis suppressor by binding to m⁶A and then promoting SLC7A11 mRNA splicing and maturation.

IL-1β promotes hypoxic vascular endothelial cell proliferation through the miR-24-3p/NKAP/NF-kB axis

Purpose: Our previous data indicated that miR-24-3p is involved in the regulation of vascular endothelial cell (EC) proliferation and migration/invasion. However, whether IL-1β affects hypoxic HUVECs by miR-24-3p is still unclear. Therefore, the present study aimed to investigate the role and underlying mechanism of interleukin 1β (IL-1β) in hypoxic HUVECs.

Methods: We assessed the mRNA expression levels of miR-24-3p, hypoxia-inducible factor-1α (HIF1A) and NF-κB-activating protein (NKAP) by quantitative real-time polymerase chain reaction (RT-qPCR). ELISA measured the expression level of IL-1β. Cell counting kit-8 (CCK-8) assays evaluated the effect of miR-24-3p or si-NKAP+miR-24 on cell proliferation (with or without IL-1β). Transwell migration and invasion assays were used to examine the effects of miR-24-3p or si-NKAP+miR-24-3p on cell migration and invasion (with or without IL-1β). Luciferase reporter assays were used to identify the target of miR-24-3p.

Results: We demonstrated that in acute myocardial infarction (AMI) patient blood samples, the expression of miR-24-3p is down-regulated, the expression of IL-1β or NKAP is up-regulated, and IL-1β or NKAP is negatively correlated with miR-24-3p. Furthermore, IL-1β promotes hypoxic HUVECs proliferation by down-regulating miR-24-3p. In addition, IL-1β also significantly promotes the migration and invasion of hypoxic HUVECs; overexpression of miR-24-3p can partially rescue hypoxic HUVECs migration and invasion. Furthermore, we discovered that NKAP is a novel target of miR-24-3p in hypoxic HUVECs. Moreover, both the overexpression of miR-24-3p and the suppression of NKAP can inhibit the NF-κB/pro-IL-1β signaling pathway. However, IL-1β mediates suppression of miR-24-3p activity, leading to activation of the NKAP/NF-κB pathway. In conclusion, our results reveal a new function of IL-1β in suppressing miR-24-3p up-regulation of the NKAP/NF-κB pathway.

High-throughput microfluidic 3D biomimetic model enabling quantitative description of the human breast tumor microenvironment

Cancer is driven by both genetic aberrations in the tumor cells and fundamental changes in the tumor microenvironment (TME). These changes offer potential targets for novel therapeutics, yet lack of in vitro 3D models recapitulating this complex microenvironment impedes such progress. Here, we generated several tumor-stroma scaffolds reflecting the dynamic in vivo breast TME, using a high throughput microfluidic system. Alginate (Alg) or alginate-alginate sulfate (Alg/Alg-S) hydrogels were used as ECM-mimics, enabling the encapsulation and culture of tumor cells, fibroblasts and immune cells (macrophages and T cells, of the innate and adaptive immune systems, respectively). Specifically, Alg/Alg-S was shown capable of capturing and presenting growth factors and cytokines with binding affinity that is comparable to heparin. Viability and cytotoxicity were shown to strongly correlate with the dynamics of cellular milieu, as well as hydrogel type. Using on-chip immunofluorescence, production of reactive oxygen species and apoptosis were imaged and quantitatively analyzed. We then show how macrophages in our microfluidic system were shifted from a proinflammatory to an immunosuppressive phenotype when encapsulated in Alg/Alg-S, reflecting in vivo TME dynamics. LC-MS proteomic profiling of tumor cells sorted from the TME scaffolds revealed upregulation of proteins involved in cell-cell interactions and immunomodulation in Alg/Alg-S scaffolds, correlating with in vivo findings and demonstrating the appropriateness of Alg/Alg-S as an ECM biomimetic. Finally, we show the formation of large tumor-derived vesicles, formed exclusively in Alg/Alg-S scaffolds. Altogether, our system offers a robust platform for quantitative description of the breast TME that successfully recapitulates in vivo patterns. STATEMENT OF SIGNIFICANCE: Cancer progression is driven by profound changes in both tumor cells and surrounding stroma. Here, we present a high throughput microfluidic system for the generation and analysis of dynamic tumor-stroma scaffolds, that mimic the complex in vivo TME cell proportions and compositions, constructing robust in vitro models for the study of the TME. Utilizing Alg/Alg-S as a bioinspired ECM, mimicking heparin's in vivo capabilities of capturing and presenting signaling molecules, we show how Alg/Alg-S induces complex in vivo-like responses in our models. Alg/Alg-S is shown here to promote dynamic protein expression patterns, that can serve as potential therapeutic targets for breast cancer treatment. Formation of large tumor-derived vesicles, observed exclusively in the Alg/Alg-S scaffolds suggests a mechanism for tumor survival.

SNAP25 Inhibits Glioma Progression by Regulating Synapse Plasticity via GLS-Mediated Glutaminolysis

Background

Neuronal activity regulated by synaptic communication exerts an important role in tumorigenesis and progression in brain tumors. Genes for soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) annotated with the function ‘vesicle’ about synaptic connectivity were identified, and synaptosomal-associated protein 25 (SNAP25), one of those proteins, was found to have discrepant expression levels in neuropathies. However, the specific mechanism and prognostic value of SNAP25 during glioma progression remain unclear.

Methods

Using RNA sequencing data from The Cancer Genome Atlas (TCGA) database, the differential synaptosis-related genes between low grade glioma (LGG) and glioblastoma (GBM) were identified as highly correlated. Cox proportional hazards regression analysis and survival analysis were used to differentiate the outcome of low- and high-risk patients, and the Chinese Glioma Genome Atlas (CGGA) cohort was used for validation of the data set. RT-qPCR, western blot, and immunohistochemistry assays were performed to examine the expression level of SNAP25 in glioma cells and samples. Functional assays were performed to identify the effects of SNAP25 knockdown and overexpression on cell viability, migration, and invasion. Liquid chromatography-high resolution mass spectrometry (LC-MS)-based metabolomics approach was presented for identifying crucial metabolic disturbances in glioma cells. In situ mouse xenograft model was used to investigate the role of SNAP25 in vivo. Then, an immunofluorescence assay of the xenograft tissue was applied to evaluate the expression of the neuronal dendron formation marker-Microtubule Associated Protein 2 (MAP2).

Results

SNAP25 was decreased in level of expression in glioma tissues and cell lines, and low-level SNAP25 indicated an unfavorable prognosis of glioma patients. SNAP25 inhibited cell proliferation, migration, invasion and fostered glutamine metabolism of glioma cells, exerting a tumor suppressor role. Overexpressed SNAP25 exerted a lower expression level of MAP2, indicating poor neuronal plasticity and connectivity. SNAP25 could regulate glutaminase (GLS)-mediated glutaminolysis, and GLS knockdown could rescue the anti-tumor effect of SNAP25 in glioma cells. Moreover, upregulated SNAP25 also decreased tumor volume and prolonged the overall survival (OS) of the xenograft mouse.

Conclusion

SNAP25, a tumor suppressor inhibited carcinogenesis of glioma via limiting glutamate metabolism by regulating GLS expression, as well as inhibiting dendritic formation, which could be considered as a novel molecular therapeutic target for glioma.

A novel lncRNA ARST represses glioma progression by inhibiting ALDOA-mediated actin cytoskeleton integrity

Background

Glioma is one of the most aggressive malignant brain tumors that is characterized with inevitably infiltrative growth and poor prognosis. ARST is a novel lncRNA whose expression level is significantly decreased in the patients with glioblastoma multiforme. However, the exact mechanisms of ARST in gliomagenesis are largely unknown.

Methods

The expressions of ARST in the glioma samples and cell lines were analyzed by qRT-PCR. FISH was utilized to detect the distribution of ARST in the glioma cells. CCK-8, EdU and flow cytometry were used to examine cellular viability, proliferation and apoptosis. Transwell and wound-healing assays were performed to determine the migratory and invasive abilities of the cells. Intracranial tumorigenesis models were established to explore the roles of ARST in vivo. RNA pulldown assay was used to examine proteins that bound to ARST. The activities of key enzymes in the glycolysis and production of lactate acid were measured by colorimetry. In addition, RIP, Co-IP, western blot and immunofluorescence were used to investigate the interaction and regulation between ARST, F-actin, ALDOA and cofilin.

Results

In this study, we reported that ARST was downregulated in the gliomas. Overexpression of ARST in the glioma cells significantly suppressed various cellular vital abilities such as cell growth, proliferation, migration and invasion. The tumorigenic capacity of these cells in vivo was reduced as well. We further demonstrated that the tumor suppressive effects of ARST could be mediated by a direct binding to a glycolytic enzyme aldolase A (ALDOA), which together with cofilin, keeping the polymerization and depolymerization of actin filaments in an orderly dynamic equilibrium. Upregulation of ARST interrupted the interaction between ALDOA and actin cytoskeleton, which led to a rapid cofilin-dependent loss of F-actin stress fibers.

Conclusions

Taken together, it is concluded that ARST performs its function via a non-metabolic pathway associated with ALDOA, which otherwise modifies the morphology and invasive properties of the glioma cells. This has added new perspective to its role in tumorigenesis, thus providing potential target for glioma diagnosis, therapy, and prognosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-01977-9.

Nuclear Factor-κB Activating Protein Plays an Oncogenic Role in Neuroblastoma Tumorigenesis and Recurrence Through the Phosphatidylinositol 3-Kinase/Protein Kinase B Signaling Pathway

Nuclear factor-κB activating protein (NKAP) is a conserved nuclear protein that acts as an oncogene in various cancers and is associated with a poor prognosis. This study aimed to investigate the role of NKAP in neuroblastoma (NB) progression and recurrence. We compared NKAP gene expression between 89 recurrence and 134 non-recurrence patients with NB by utilizing the ArrayExpress database. The relationship between NKAP expression and clinicopathological features was evaluated by correlation analysis. We knocked down NKAP expression in NB1 and SK-N-SH cells by small interfering RNA transfection to verify its role in tumor proliferation, apoptosis, and the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. NKAP gene expression in NB tissues was significantly overexpressed in the recurrence group compared with the non-recurrence group, and NKAP was enriched in the PI3K/AKT pathway. Correlation analysis revealed NKAP expression was correlated with chromosome 11q deletion in patients with NB. Knockdown of NKAP expression significantly inhibited the proliferation and promoted the apoptosis of NB1 and SK-N-SH cells. Moreover, we found that small interfering NKAP significantly reduced p-PI3K and p-AKT expression. NKAP knockdown played an oncogenic role in NB by inhibiting PI3K/AKT signaling pathway activations both in vitro and in vivo. Our research revealed that NKAP mediates NB cells by inhibited proliferation and promoted apoptosis through activating the PI3K/AKT signaling pathways, and the expression of NKAP may act as a novel biomarker for predicting recurrence and chromosome 11q deletion in patients with NB.

CREBBP/EP300 mutations promoted tumor progression in diffuse large B-cell lymphoma through altering tumor-associated macrophage polarization via FBXW7-NOTCH-CCL2/CSF1 axis

Epigenetic alterations play an important role in tumor progression of diffuse large B-cell lymphoma (DLBCL). However, the biological relevance of epigenetic gene mutations on tumor microenvironment remains to be determined. The core set of genes relating to histone methylation (KMT2D, KMT2C, EZH2), histone acetylation (CREBBP, EP300), DNA methylation (TET2), and chromatin remodeling (ARID1A) were detected in the training cohort of 316 patients by whole-genome/exome sequencing (WGS/WES) and in the validation cohort of 303 patients with newly diagnosed DLBCL by targeted sequencing. Their correlation with peripheral blood immune cells and clinical outcomes were assessed. Underlying mechanisms on tumor microenvironment were investigated both in vitro and in vivo. Among all 619 DLBCL patients, somatic mutations in KMT2D (19.5%) were most frequently observed, followed by mutations in ARID1A (8.7%), CREBBP (8.4%), KMT2C (8.2%), TET2 (7.8%), EP300 (6.8%), and EZH2 (2.9%). Among them, CREBBP/EP300 mutations were significantly associated with decreased peripheral blood absolute lymphocyte-to-monocyte ratios, as well as inferior progression-free and overall survival. In B-lymphoma cells, the mutation or knockdown of CREBBP or EP300 inhibited H3K27 acetylation, downregulated FBXW7 expression, activated the NOTCH pathway, and downstream CCL2/CSF1 expression, resulting in tumor-associated macrophage polarization to M2 phenotype and tumor cell proliferation. In B-lymphoma murine models, xenografted tumors bearing CREBBP/EP300 mutation presented lower H3K27 acetylation, higher M2 macrophage recruitment, and more rapid tumor growth than those with CREBBP/EP300 wild-type control via FBXW7-NOTCH-CCL2/CSF1 axis. Our work thus contributed to the understanding of aberrant histone acetylation regulation on tumor microenvironment as an alternative mechanism of tumor progression in DLBCL.

lncRNA-Xist/miR-101-3p/KLF6/C/EBPα axis promotes TAM polarization to regulate cancer cell proliferation and migration

The phenotypic switch in tumor-associated macrophages (TAMs) mediates immunity escape of cancer. However, the underlying mechanisms in the TAM phenotypic switch have not been systematically elucidated. In this study, long noncoding RNA (lncRNA)-Xist, CCAAT/enhancer-binding protein (C/EBP)α, and Kruppel-like factor 6 (KLF6) were upregulated, whereas microRNA (miR)-101 was downregulated in M1 macrophages-type (M1). Knockdown of Xist or overexpression of miR-101 in M1 could induce M1-to-M2 macrophage-type (M2) conversion to promote cell proliferation and migration of breast and ovarian cancer by inhibiting C/EBPα and KLF6 expression. Furthermore, miR-101 could combine with both Xist and C/EBPα and KLF6 through the same microRNA response element (MRE) predicted by bioinformatics and verified by luciferase reporter assays. Moreover, we found that miR-101 knockdown restored the decreased M1 marker and the increased M2 marker expression and also reversed the promotion of proliferation and migration of human breast cancer cells (MCF-7) and human ovarian cancer (OV) cells caused by silencing Xist. Generally, the present study indicates that Xist could mediate macrophage polarization to affect cell proliferation and migration of breast and ovarian cancer by competing with miR-101 to regulate C/EBPα and KLF6 expression. The promotion of Xist expression in M1 macrophages and inhibition of miR-101 expression in M2 macrophages might play an important role in inhibiting breast and ovarian tumor proliferation and migration abilities.

Molecular and Clinical Characterization of a Novel Prognostic and Immunologic Biomarker FAM111A in Diffuse Lower-Grade Glioma

Background

Family with sequence similarity 111 member A (FAM111A), as a replication factor required for proliferating cell nuclear antigen (PCNA) loading, has been demonstrated a possible association with carcinogenesis. However, the role of FAM111A in lower-grade glioma (LGG) remains unclear. We aim at investigating the expression and function of FAM111A in lower-grade glioma at the molecular and clinical levels.

Methods

In total, 711 lower-grade glioma samples were analyzed in our research, including 182 RNA-seq data from the Chinese Glioma Genome Atlas (CGGA) dataset and 529 RNA-seq data from The cancer Genome Atlas (TCGA) dataset. R language and the GraphPad software were used for the majority of statistical analysis and graphical work.

Results

FAM111A expression was overexpressed in WHO grade III and IDH-wildtype lower-grade glioma. FAM111A was significantly downregulated in the IDHmut-Codel molecular subtype. Univariate and multivariate Cox analysis demonstrated that FAM111A was an independent prognostic factor in LGG patients. Functional characterization of FAM111A revealed that it was associated with inflammatory response and immune response to tumor cells. FAM111A could also act as an indicator of the stromal and immune population, especially for monocytic lineage, myeloid dendritic cells and fibroblasts. It was positively correlated with macrophages, especially the M2 macrophage cells. Furthermore, FAM111A revealed predictive value for the immune subtypes and immune checkpoint blockade therapy.

Conclusion

FAM111A expression was closely related to the malignant phenotype, molecular pathology and immune response of lower-grade glioma. It might be a promising target for LGG immunotherapeutic strategies.

A computational guided, functional validation of a novel therapeutic antibody proposes Notch signaling as a clinical relevant and druggable target in glioma

The Notch signaling network determines stemness in various tissues and targeting signaling activity in malignant brain cancers by gamma-secretase inhibitors (GSI) has shown promising preclinical success. However, the clinical translation remains challenging due to severe toxicity side effects and emergence of therapy resistance. Better anti-Notch directed therapies, specifically directed against the tumor promoting Notch receptor 1 signaling framework, and biomarkers predicting response to such therapy are of highest clinical need. We assessed multiple patient datasets to probe the clinical relevance Notch1 activation and possible differential distribution amongst molecular subtypes in brain cancers. We functionally assessed the biological effects of the first-in-human tested blocking antibody against Notch1 receptor (brontictuzumab, BRON) in a collection of glioma stem-like cell (GSC) models and compared its effects to genetic Notch1 inhibition as well as classical pharmacological Notch inhibitor treatment using gamma-secretase inhibitor MRK003. We also assess effects on Wingless (WNT) stem cell signaling activation, which includes the interrogation of genetic WNT inhibition models. Our computed transcriptional Notch pathway activation score is upregulated in neural stem cells, as compared to astrocytes; as well as in GSCs, as compared to differentiated glioblastoma cells. Moreover, the Notch signature is clinical predictive in our glioblastoma patient discovery and validation cohort. Notch signature is significantly increased in tumors with mutant IDH1 genome and tumors without 1p and 19q co-deletion. In GSCs with elevated Notch1 expression, BRON treatment blocks transcription of Notch pathway target genes Hes1/Hey1, significantly reduced the amount of cleaved Notch1 receptor protein and caused significantly impairment of cellular invasion. Benchmarking this phenotype to those observed with genetic Notch1 inhibition in corresponding cell models did result in higher reduction of cell invasion under chemotherapy. BRON treatment caused signs of upregulation of Wingless (WNT) stem cell signaling activity, and vice versa, blockage of WNT signaling caused induction of Notch target gene expression in our models. We extend the list of evidences that elevated Notch signal expression is a biomarker signature declaring stem cell prevalence and useful for predicting negative clinical course in glioblastoma. By using functional assays, we validated a first in man tested Notch1 receptor specific antibody as a promising drug candidate in the context of neuro oncology and propose biomarker panel to predict resistance and therapy success of this treatment option. We note that the observed phenotype seems only in part due to Notch1 blockage and the drug candidate leads to activation of off target signals. Further studies addressing a possible emergence of therapy resistance due to WNT activation need to be conducted. We further validated our 3D disease modeling technology to be of benefit for drug development projects.

NKAP promotes renal cell carcinoma growth via AKT/mTOR signalling pathway

Renal cell carcinoma (RCC) is the seventh most common site for malignant tumours worldwide leading to a high risk of death. NKAP is a conserved nuclear protein that has critical roles in the development, maturation, and functional acquisition of T cells, iNKT cells, and cancers. But the function and underlying mechanism of NKAP in RCC is still unknown. Knockdown of NKAP by siRNA interference (siNKAP) was used to explore the roles of NAKP in human RCC cells. Here, we found that siNKAP strongly inhibited the proliferation and motility of Ketr-3 and 786-0 cells and induced cell apoptosis. Furthermore, the expression of anti-apoptotic protein Bcl2 in the siNKAP group was strongly decreased, while the expression of pro-apoptotic proteins Bax, cleaved Caspase-3, and cleaved Caspase-9 was significantly increased. Finally, to identify the potential mechanisms, we detected related proteins of the AKT/mTOR signalling pathway by western blot assay. We found that siNKAP significantly inhibited the expression of cyclin D1 and the phosphorylation of AKT and mTOR. The findings for the first time reveal that the AKT/mTOR signalling pathway is involved in the oncogenic role of NKAP in RCC, which provides an important basis for exploring the molecular regulation mechanism of RCC. SIGNIFICANCE OF THE STUDY: There is an urgent need to study the molecular mechanisms involved in RCC to promote the development of early diagnosis and more effective treatment options. This research provides an important basis for exploring the accurate regulatory mechanism of NKAP in RCC and a novel perspective to find the potential utility of NKAP inhibitors for RCC therapy.

FADD in Cancer: Mechanisms of Altered Expression and Function, and Clinical Implications

FADD was initially described as an adaptor molecule for death receptor-mediated apoptosis, but subsequently it has been implicated in nonapoptotic cellular processes such as proliferation and cell cycle control. During the last decade, FADD has been shown to play a pivotal role in most of the signalosome complexes, such as the necroptosome and the inflammasome. Interestingly, various mechanisms involved in regulating FADD functions have been identified, essentially posttranslational modifications and secretion. All these aspects have been thoroughly addressed in previous reviews. However, FADD implication in cancer is complex, due to pleiotropic effects. It has been reported either as anti- or protumorigenic, depending on the cell type. Regulation of FADD expression in cancer is a complex issue since both overexpression and downregulation have been reported, but the mechanisms underlying such alterations have not been fully unveiled. Posttranslational modifications also constitute a relevant mechanism controlling FADD levels and functions in tumor cells. In this review, we aim to provide detailed, updated information on alterations leading to changes in FADD expression and function in cancer. The participation of FADD in various biological processes is recapitulated, with a mention of interesting novel functions recently proposed for FADD, such as regulation of gene expression and control of metabolic pathways. Finally, we gather all the available evidence regarding the clinical implications of FADD alterations in cancer, especially as it has been proposed as a potential biomarker with prognostic value.