KPNA2 promotes metabolic reprogramming in glioblastomas by regulation of c-myc

USP7 promotes the malignant progression of osteosarcoma through the KPNA2/PKLR axis

BACKGROUND

Osteosarcoma, a common primary bone malignancy, poses significant challenges in clinical treatment due to its high metastatic potential and resistance to chemotherapy. The karyopherin subunit alpha 2 (KPNA2) is a member of the karyopherin family and has been implicated in the regulation of various cellular processes. However, the role of KPNA2 in osteosarcoma development and progression remains unclear.

METHODS

The expression levels of KPNA2 and pyruvate kinase L/R (PKLR) mRNA were assessed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). Protein expression of KPNA2, ubiquitin-specific peptidase 7 (USP7), and PKLR was determined via western blotting. Cell viability, proliferation, apoptosis, invasion, and migration were evaluated using CCK-8, EdU, flow cytometry, transwell invasion, and wound-healing assays, respectively. Glucose consumption and lactate production were measured using colorimetric assays. The interaction between USP7 and KPNA2 was identified through co-immunoprecipitation (Co-IP) and immunofluorescence co-localization assays. In vivo experiments were conducted to validate the effects of KPNA2 silencing and PKLR overexpression on osteosarcoma cell growth. The positive expression rates of Ki67 and PKLR were assessed using immunohistochemistry (IHC) assays.

RESULTS

KPNA2 expression was upregulated in osteosarcoma tissues and cells. Silencing KPNA2 suppressed osteosarcoma cell proliferation, invasion, migration, and glycolysis, while inducing apoptosis. USP7 stabilized KPNA2 through its deubiquitinating activity, and USP7 silencing inhibited the malignant phenotypes of osteosarcoma cells by regulating KPNA2. Additionally, KPNA2 upregulated PKLR expression, and overexpression of PKLR mitigated the effects of KPNA2 silencing on the malignant progression of osteosarcoma cells both in vitro and in vivo.

CONCLUSION

The deubiquitination of KPNA2 by USP7 promoted the malignant progression of osteosarcoma by increasing PKLR expression. This study highlights the clinical significance of targeting the KPNA2-USP7-PKLR axis as a potential therapeutic strategy for the treatment of osteosarcoma.

KPNA2 promotes osteosarcoma progression by regulating the alternative splicing of DDX3X mediated by YBX1

Osteosarcoma (OS) is a rapidly progressive primary malignant bone tumor that occurs in children and adolescents aged between 15 and 19 years and adults aged over 60 years. As alternative splicing (AS) changes caused by abnormal splicing factors contribute to tumor progression, gene expression and AS analyses were performed on 44 osteosarcoma patients to create a genome-wide co-expression network of RNA-binding proteins (RBPs), AS events, and AS genes. A gain- or loss-of-function osteosarcoma cell model was established, and an interactive network analysis and enrichment analysis were performed. Karyopherin Subunit Alpha 2 (KPNA2) negatively correlated with patient survival. KPNA2 transports splicing factor Y-box Binding Protein 1 (YBX1) into the nucleus and YBX1 accelerates the degradation of the ATP-dependent RNA helicase DDX3X (DDX3X) through the nonsense-mediated decay (NMD) pathway to promote intron retention of the DDX3X gene, thus reducing DDX3X protein levels. KPNA2/YBX1 axis regulates the stability of DDX3X mRNA and cell cycle progression. KPNA2/YBX1/DDX3X axis might be potential targets for inhibiting disease progression and improving OS patient survival. It integrates AS control of DDX3X into the progression of OS and represents a potential prognostic biomarker and therapeutic target for OS therapy.

Are we better together? Addressing a combined treatment of pitavastatin and temozolomide for brain cancer

Pitavastatin is commonly prescribed to treat hypercholesterolemia through the regulation of cholesterol biosynthesis. Interestingly, it has also demonstrated a great potential for treating brain tumors, although the detailed cytotoxic mechanism, particularly in glioblastoma, remains incompletely understood. This work explores the activity of pitavastatin in 2D and 3D glioblastoma models, in an attempt to provide a more representative and robust overview of its anticancer potential in glioblastoma. The results show that not only is pitavastatin 10-1000 times-fold more effective in reducing tumoral metabolic activity than temozolomide, but also demonstrate a synergistic activity with this alkylating drug. In addition, low micromolar concentrations of this statin strongly impair the growth and the invasion ability of multicellular tumor spheroids. The obtained qRT-PCR and proteomics data highlight the modulation of cell death via apoptosis (BAX/BCL2, CASP9) and autophagy (BECN1, BNIP3, BNIP3L and LC3B), as well as an epithelial to mesenchymal transition blockage (HTRA1, SERPINE1, WNT5A, ALDH3B1 and EPHA2) and remodeling of the extracellular matrix (VCAN, SERPINE1 and TGFBI). Overall, these results lay the foundation for further investigations on the potential combinatory clinical treatment with temozolomide.

HPV16 integration regulates ferroptosis resistance via the c-Myc/miR-142-5p/HOXA5/SLC7A11 axis during cervical carcinogenesis

BACKGROUND

Ferroptosis, a newly identified form of regulated cell death triggered by small molecules or specific conditions, plays a significant role in virus-associated carcinogenesis. However, whether tumours arising after high-risk HPV integration are associated with ferroptosis is unexplored and remains enigmatic.

METHODS

High-risk HPV16 integration was analysed by high-throughput viral integration detection (HIVID). Ferroptosis was induced by erastin, and the levels of ferroptosis were assessed through the measurement of lipid-reactive oxygen species (ROS), malondialdehyde (MDA), intracellular Fe2+ level and transmission electron microscopy (TEM). Additionally, clinical cervical specimens and an in vivo xenograft model were utilized for the study.

RESULTS

Expression of HPV16 integration hot spot c-Myc negatively correlates with ferroptosis during the progression of cervical squamous cell carcinoma (CSCC). Further investigation revealed that the upregulated oncogene miR-142-5p in HPV16-integrated CSCC cells served as a critical downstream effector of c-Myc in its target network. Inhibiting miR-142-5p significantly decreased the ferroptosis-suppressing effect mediated by c-Myc. Through a combination of computational and experimental approaches, HOXA5 was identified as a key downstream target gene of miR-142-5p. Overexpression of miR-142-5p suppressed HOXA5 expression, leading to decreased accumulation of intracellular Fe2+ and lipid peroxides (ROS and MDA). HOXA5 increased the sensitivity of CSCC cells to erastin-induced ferroptosis via transcriptional downregulation of SLC7A11, a negative regulator of ferroptosis. Importantly, c-Myc knockdown increased the anti-tumour activity of erastin by promoting ferroptosis both in vitro and in vivo.

CONCLUSIONS

Collectively, these data indicate that HPV16 integration hot spot c-Myc plays a novel and indispensable role in ferroptosis resistance by regulating the miR-142-5p/HOXA5/SLC7A11 signalling axis and suggest a potential therapeutic approach for HPV16 integration-related CSCC.

Metabolic Contrasts: Fatty Acid Oxidation and Ketone Bodies in Healthy Brains vs. Glioblastoma Multiforme

The metabolism of glucose and lipids plays a crucial role in the normal homeostasis of the body. Although glucose is the main energy substrate, in its absence, lipid metabolism becomes the primary source of energy. The main means of fatty acid oxidation (FAO) takes place in the mitochondrial matrix through β-oxidation. Glioblastoma (GBM) is the most common form of primary malignant brain tumor (45.6%), with an incidence of 3.1 per 100,000. The metabolic changes found in GBM cells and in the surrounding microenvironment are associated with proliferation, migration, and resistance to treatment. Tumor cells show a remodeling of metabolism with the use of glycolysis at the expense of oxidative phosphorylation (OXPHOS), known as the Warburg effect. Specialized fatty acids (FAs) transporters such as FAT, FABP, or FATP from the tumor microenvironment are overexpressed in GBM and contribute to the absorption and storage of an increased amount of lipids that will provide sufficient energy used for tumor growth and invasion. This review provides an overview of the key enzymes, transporters, and main regulatory pathways of FAs and ketone bodies (KBs) in normal versus GBM cells, highlighting the need to develop new therapeutic strategies to improve treatment efficacy in patients with GBM.

Metabolic Roles of HIF1, c-Myc, and p53 in Glioma Cells

The metabolic reprogramming that promotes tumorigenesis in glioblastoma is induced by dynamic alterations in the hypoxic tumor microenvironment, as well as in transcriptional and signaling networks, which result in changes in global genetic expression. The signaling pathways PI3K/AKT/mTOR and RAS/RAF/MEK/ERK stimulate cell metabolism, either directly or indirectly, by modulating the transcriptional factors p53, HIF1, and c-Myc. The overexpression of HIF1 and c-Myc, master regulators of cellular metabolism, is a key contributor to the synthesis of bioenergetic molecules that mediate glioma cell transformation, proliferation, survival, migration, and invasion by modifying the transcription levels of key gene groups involved in metabolism. Meanwhile, the tumor-suppressing protein p53, which negatively regulates HIF1 and c-Myc, is often lost in glioblastoma. Alterations in this triad of transcriptional factors induce a metabolic shift in glioma cells that allows them to adapt and survive changes such as mutations, hypoxia, acidosis, the presence of reactive oxygen species, and nutrient deprivation, by modulating the activity and expression of signaling molecules, enzymes, metabolites, transporters, and regulators involved in glycolysis and glutamine metabolism, the pentose phosphate cycle, the tricarboxylic acid cycle, and oxidative phosphorylation, as well as the synthesis and degradation of fatty acids and nucleic acids. This review summarizes our current knowledge on the role of HIF1, c-Myc, and p53 in the genic regulatory network for metabolism in glioma cells, as well as potential therapeutic inhibitors of these factors.

Single-molecule RNA-FISH analysis reveals stochasticity in reactivation of latent HIV-1 regulated by Nuclear Orphan Receptors NR4A and cMYC

HIV-1 eradication strategies require complete reactivation of HIV-1 latent cells by Latency Reversing Agents (LRA). Current methods lack effectiveness due to incomplete proviral reactivation. We employed a single-molecule RNA-FISH (smRNA-FISH) and FISH-Quant analysis and found that proviral reactivation is highly variable from cell-to-cell, stochastic, and occurs in bursts and waves, with different kinetics in response to diverse LRAs. Approximately 1-5% of latent cells exhibited stochastic reactivation without LRAs. Through single-cell RNA-seq analysis, we identified NR4A3 and cMYC as extrinsic factors associated with stochastic HIV-1 reactivation. Concomitant with HIV-1 reactivation cMYC was downregulated and NR4A3 was upregulated in both latent cell lines and primary CD4+ T-cells from aviremic patients. By inhibiting cMYC using SN-38, an active metabolite of irinotecan, we induced NR4A3 and HIV-1 expression. Our results suggest that inherent stochasticity in proviral reactivation contributes to cell-to-cell variability, which could potentially be modulated by drugs targeting cMYC and NR4A3.

TIMP1/CHI3L1 facilitates glioma progression and immunosuppression via NF-κB activation

Gliomas are highly heterogeneous brain tumours that are resistant to therapies. The molecular signatures of gliomas play a high-ranking role in tumour prognosis and treatment. In addition, patients with gliomas with a mesenchymal phenotype manifest overpowering immunosuppression and sophisticated resistance to treatment. Thus, studies on gene/protein coexpression networks and hub genes in gliomas holds promise in determining effective treatment strategies. Therefore, in this study, we aimed to. Using average linkage hierarchical clustering, 13 modules and 224 hub genes were described. Top ten hub genes (CLIC1, EMP3, TIMP1, CCDC109B, CASP4, MSN, ANXA2P2, CHI3L1, TAGLN2, S100A11), selected from the most meaningful module, were associated with poor prognosis. String analysis, co-immunoprecipitation and immunofluorescence revealed a significant correlation between TIMP1 and CHI3L1. Furthermore, we found, both in vivo and in vitro, that TIMP1 promoted gliomagenesis via CHI3L1 overexpression as well as NF-κB activation. TIMP1 expression correlated with tumour immune infiltration and immune checkpoint-related gene expression. In addition, TIMP1 resulted in immunosuppressive macrophage polarization. In summary, TIMP1/CHI3L1 might be perceived as a diagnostic marker and an immunotherapy target for gliomas.

MALAT1 DEREPRESSES MIR-433-3P-MEDIATED RPTOR SUPPRESSION TO IMPAIR AUTOPHAGY AND DRIVE PYROPTOSIS IN ENDOTOXEMIA

ABSTRACT

Objective: Autophagy elevation in endotoxemia plays a protective role by negatively regulating the pyroptosis of vascular endothelial cells, but the molecular mechanisms are still poorly understood. The present study aimed to identify the mechanism underlying autophagy and pyroptosis in endotoxemia. Methods: Bioinformatics analysis and whole-gene transcriptome sequencing prediction were used to identify the endotoxemia-related lncRNA-miRNA-mRNA axis of interest. Human umbilical vein endothelial cells (HUVECs) were activated by lipopolysaccharide (LPS) to mimic the inflammatory environment encountered in endotoxemia. Autophagy and pyroptosis of LPS-treated HUVECs were assessed in response to the knockdown of MALAT1 (metastasis-associated lung adenocarcinoma transcript 1)/miR-433-3p (miRNA-433-3p)/RPTOR (regulatory-associated protein of mTOR). The binding affinity of MALAT1, miR-433-3p, and RPTOR was detected by RNA pull-down and luciferase activity assays. The endothelial cell-specific RPTOR knockout mice were developed and rendered septic using LPS induction to verify the role of RPTOR in autophagy, pyroptosis, and inflammatory response in vivo . Results: The in vitro experiments indicated that LPS could stimulate HUVECs to highly express RPTOR, and its knockdown enhanced cellular autophagy and restricted pyroptosis to curb inflammatory responses. Mechanically, MALAT1 is competitively bound to miR-433-3p to release RPTOR expression, thereby promoting pyroptosis and aggravating endotoxemia. In vivo experiments further confirmed that the knockdown of RPTOR activated autophagy and curtailed pyroptosis in septic mice. Conclusion: MALAT1 is highly expressed in endotoxemia. MALAT1 promotes RPTOR expression by competitively absorbing miR-433-3p, inhibits LPS-activated HUVEC cell autophagy, promotes cell death, enhances LPS-induced inflammatory activation of vascular endothelial cells, and ultimately promotes the progression of endotoxemia.

KPNA2 suppresses porcine epidemic diarrhea virus replication by targeting and degrading virus envelope protein through selective autophagy

IMPORTANCE

Porcine epidemic diarrhea, characterized by vomiting, dehydration, and diarrhea, is an acute and highly contagious enteric disease caused by porcine epidemic diarrhea virus (PEDV) in neonatal piglets. This disease has caused large economic losses to the porcine industry worldwide. Thus, identifying the host factors involved in PEDV infection is important to develop novel strategies to control PEDV transmission. This study shows that PEDV infection upregulates karyopherin α 2 (KPNA2) expression in Vero and intestinal epithelial (IEC) cells. KPNA2 binds to and degrades the PEDV E protein via autophagy to suppress PEDV replication. These results suggest that KPNA2 plays an antiviral role against PEDV. Specifically, knockdown of endogenous KPNA2 enhances PEDV replication, whereas its overexpression inhibits PEDV replication. Our data provide novel KPNA2-mediated viral restriction mechanisms in which KPNA2 suppresses PEDV replication by targeting and degrading the viral E protein through autophagy. These mechanisms can be targeted in future studies to develop novel strategies to control PEDV infection.

miR-122-5p Promotes Peripheral and Central Nervous System Inflammation in a Mouse Model of Intracerebral Hemorrhage via Disruption of the MLLT1/PI3K/AKT Signaling

Intracerebral hemorrhage (ICH) is a recognized central nervous system inflammation complication. Several microRNAs (miRNAs or miRs) have been documented to be vital modulators in peripheral and central nervous system inflammation. Based on whole transcriptome sequencing and bioinformatics analysis, this study aims to reveal the possible molecular mechanisms by which miR-122-5p affects the inflammatory response in the peripheral and central nervous system in a mouse model of ICH. Differentially expressed ICH-related miRNAs were screened. Adeno-associated viral vectors were used to knock down miR-122-5p in mice to evaluate the effect of miR-122-5p on peripheral and central nervous system inflammation. The downstream target gene of miR-122-5p was analyzed. Neurons were isolated from mice and treated with hemin to construct an in vitro model of ICH, followed by transduction with miR-122-5p mimic or combined with oe-MLLT1. The neurons were then co-cultured with microglia BV2 to assess their activation. It was found that miR-122-5p was highly expressed in ICH, and MLLT1 was lowly expressed. In vivo experiments showed that miR-122-5p knockdown decreased neurological deficits, BBB permeability, and inflammation in the peripheral and central nervous system in ICH mice. It involved its binding to MLLT1 and downregulation of the activity of the PI3K/AKT pathway. In vitro data exhibited that miR-122-5p stimulated the generation of inflammatory factors and microglia activation by targeting MLLT1 and inhibiting the PI3K/AKT pathway. Collectively, our work reveals a novel miR-122-5p/MLLT1-mediated regulatory network in ICH that may be a viable target for neuroinflammation alleviation.

TP53-PTEN-NF1 depletion in human brain organoids produces a glioma phenotype in vitro

Glioblastoma (GBM) is fatal and the study of therapeutic resistance, disease progression, and drug discovery in GBM or glioma stem cells is often hindered by limited resources. This limitation slows down progress in both drug discovery and patient survival. Here we present a genetically engineered human cerebral organoid model with a cancer-like phenotype that could provide a basis for GBM-like models. Specifically, we engineered a doxycycline-inducible vector encoding shRNAs enabling depletion of the TP53, PTEN, and NF1 tumor suppressors in human cerebral organoids. Designated as inducible short hairpin-TP53-PTEN-NF1 (ish-TPN), doxycycline treatment resulted in human cancer-like cerebral organoids that effaced the entire organoid cytoarchitecture, while uninduced ish-TPN cerebral organoids recapitulated the normal cytoarchitecture of the brain. Transcriptomic analysis revealed a proneural GBM subtype. This proof-of-concept study offers a valuable resource for directly investigating the emergence and progression of gliomas within the context of specific genetic alterations in normal cerebral organoids.

ISG15 and ISGylation modulates cancer stem cell-like characteristics in promoting tumor growth of anaplastic thyroid carcinoma

BACKGROUND

Anaplastic thyroid carcinoma (ATC) was a rare and extremely malignant endocrine cancer with the distinct hallmark of high proportion of cancer stem cell-like characteristics. Therapies aiming to cancer stem-like cells (CSCs) were emerging as a new direction in cancer treatment, but targeting ATC CSCs remained challenging, mainly due to incomplete insights of the regulatory mechanism of CSCs. Here, we unveiled a novel role of ISG15 in the modulation of ATC CSCs.

METHODS

The expression of ubiquitin-like proteins were detected by bioinformatics and immunohistochemistry. The correlation between ISG15 expression and tumor stem cells and malignant progression of ATC was analyzed by single-cell RNA sequence from the Gene Expression Omnibus. Flow cytometry combined with immunofluorescence were used to verify the enrichment of ISG15 and ISGyaltion in cancer stem cells. The effect and mechanism of ISG15 and KPNA2 on cancer stem cell-like characteristics of ATC cells were determined by molecular biology experiments. Mass spectrometry combined with immunoprecipitation to screen the substrates of ISG15 and validate its ISGylation modification. Nude mice and zebrafish xenograft models were utilized to demonstrate that ISG15 regulates stem cell characteristics and promotes malignant progression of ATC.

RESULTS

We found that among several ubiquitin proteins, only ISG15 was aberrantly expressed in ATC and enriched in CSCs. Single-cell sequencing analysis revealed that abnormal expression of ISG15 were intensely associated with stemness and malignant cells in ATC. Inhibition of ISG15 expression dramatically attenuated clone and sphere formation of ATC cells, and facilitated its sensitivity to doxorubicin. Notably, overexpression of ISGylation, but not the non-ISGylation mutant, effectively reinforced cancer stem cell-like characteristics. Mechanistically, ISG15 mediated the ISGylation of KPNA2 and impeded its ubiquitination to promote stability, further maintaining cancer stem cell-like characteristics. Finally, depletion of ISG15 inhibited ATC growth and metastasis in xenografted mouse and zebrafish models.

CONCLUSION

Our studies not only provided new insights into potential intervention strategies targeting ATC CSCs, but also uncovered the novel biological functions and mechanisms of ISG15 and ISGylation for maintaining ATC cancer stem cell-like characteristics.

The "Superoncogene" Myc at the Crossroad between Metabolism and Gene Expression in Glioblastoma Multiforme

The concept of the Myc (c-myc, n-myc, l-myc) oncogene as a canonical, DNA-bound transcription factor has consistently changed over the past few years. Indeed, Myc controls gene expression programs at multiple levels: directly binding chromatin and recruiting transcriptional coregulators; modulating the activity of RNA polymerases (RNAPs); and drawing chromatin topology. Therefore, it is evident that Myc deregulation in cancer is a dramatic event. Glioblastoma multiforme (GBM) is the most lethal, still incurable, brain cancer in adults, and it is characterized in most cases by Myc deregulation. Metabolic rewiring typically occurs in cancer cells, and GBM undergoes profound metabolic changes to supply increased energy demand. In nontransformed cells, Myc tightly controls metabolic pathways to maintain cellular homeostasis. Consistently, in Myc-overexpressing cancer cells, including GBM cells, these highly controlled metabolic routes are affected by enhanced Myc activity and show substantial alterations. On the other hand, deregulated cancer metabolism impacts Myc expression and function, placing Myc at the intersection between metabolic pathway activation and gene expression. In this review paper, we summarize the available information on GBM metabolism with a specific focus on the control of the Myc oncogene that, in turn, rules the activation of metabolic signals, ensuring GBM growth.

KPNA2 promotes angiogenesis by regulating STAT3 phosphorylation

PURPOSE

Angiogenesis is involved in many pathological and physiological processes and is mainly driven by hypoxia. Karyopherin subunit alpha 2 (KPNA2), a member of the nuclear transport protein family, was recently shown to be induced by hypoxia in various types of tumours, so we aimed to investigate the role and mechanism of KPNA2 in angiogenesis under hypoxia.

MATERIALS AND METHODS

After overexpression or knockdown of KPNA2 in human umbilical vein endothelial cells (HUVEC) by adenovirus vector infection, the tube formation, proliferation and migration of HUVEC under hypoxia were detected by tubule formation assay, 5-ethynyl-2'-deoxyuridine (EdU) staining and Transwell assay, respectively. After overexpression or knockdown of KPNA2 in a murine hindlimb ischemia model by local injection of purified adenovirus vector into the gastrocnemius muscle, blood flow changes were examined with a laser Doppler system. Changes in KPNA2-binding proteins under hypoxia were detected by immunoprecipitation-mass spectrometry (IP-MS) and co-immunoprecipitation (Co-IP). The effect of KPNA2 on signal transducer and activator of transcription 3 (STAT3) was detected by Western blotting and quantitative RT‒PCR.

RESULTS

KPNA2 was upregulated in the HUVEC hypoxia model and murine hindlimb ischemia model. Overexpression of KPNA2 increased the proliferation, migration and tube formation of HUVEC under hypoxia, while knockdown of KPNA2 reduced the proliferation, migration and tube formation of HUVEC. Overexpression of KPNA2 promoted the restoration of blood flow in the murine hindlimb ischemia model, while knockout of KPNA2 inhibited the restoration of blood flow in the murine hindlimb ischemia model. Mechanistically, hypoxia promoted the binding of STAT3 to KPNA2. Overexpression of KPNA2 promoted STAT3 phosphorylation and then upregulated vascular endothelial growth factor (VEGF) and angiopoietin 2(ANGPT2), whereas knockdown of KPNA2 inhibited STAT3 phosphorylation and then downregulated VEGF and ANGPT2.

CONCLUSION

Our study demonstrates that hypoxia promotes the binding of STAT3 to KPNA2 and KPNA2 promotes angiogenesis under hypoxia by promoting the binding of STAT3 and JAK1 and regulating STAT3 phosphorylation.

IRF2 Destabilizes Oncogenic KPNA2 to Modulate the Development of Osteosarcoma

Osteosarcomas (OS) are the most common primary malignant bone tumor. Emerging evidence revealed that karyopherin alpha 2 (KPNA2) was strongly associated with the tumorigenesis and development of numerous human cancers. The aim of the present study was to investigate the expression pattern, biological functions, and underlying mechanism of KPNA2 in OS. Bioinformatics TFBIND online was applied to forecast transcription factor (TF) binding sites in the promoter region of KPNA2. The expression profile of KPNA2 in OS tissues were firstly assessed. CCK8, colony formation, wound healing, and Transwell assays were used to assess cell viability, proliferation, and migration in vitro, and in vivo experiments were performed to explore the effects of KPNA2 and interferon regulatory factor-2 (IRF2) on tumor growth. Furthermore, the correlation between IRF2 and KPNA2 was investigated using chromatin immunoprecipitation (ChIP), RT-qPCR, western blot, and dual-luciferase assays. KPNA2 was obviously upregulated, while IRF2 decreased significantly in OS tissues and cell lines, as well as negatively correlated with each other. KPNA2 removal remarkably suppressed OS cell growth, migration, invasion in vitro, and tumor growth in vivo, while IRF2 knockdown exerts an opposing effect. IRF2 binds to the KPNA2 promoter to modulate the malignant phenotypes of OS cells by regulating epithelial-to-mesenchymal transition (EMT). The present study demonstrated that KPNA2 performed the oncogenic function, possibly regulating tumor development through EMT. Importantly, it was confirmed that IRF2 serves as a potential upstream TF of KPNA2 involved in the regulation of EMT progress in OS.

Evaluation of the role of KPNA2 mutations in breast cancer prognosis using bioinformatics datasets

Breast cancer, comprising of several sub-phenotypes, is a leading cause of female cancer-related mortality in the UK and accounts for 15% of all cancer cases. Chemoresistant sub phenotypes of breast cancer remain a particular challenge. However, the rapidly-growing availability of clinical datasets, presents the scope to underpin a data-driven precision medicine-based approach exploring new targets for diagnostic and therapeutic interventions.We report the application of a bioinformatics-based approach probing the expression and prognostic role of Karyopherin-2 alpha (KPNA2) in breast cancer prognosis. Aberrant KPNA2 overexpression is directly correlated with aggressive tumour phenotypes and poor patient survival outcomes. We examined the existing clinical data available on a range of commonly occurring mutations of KPNA2 and their correlation with patient survival.Our analysis of clinical gene expression datasets show that KPNA2 is frequently amplified in breast cancer, with differences in expression levels observed as a function of patient age and clinicopathologic parameters. We also found that aberrant KPNA2 overexpression is directly correlated with poor patient prognosis, warranting further investigation of KPNA2 as an actionable target for patient stratification or the design of novel chemotherapy agents.In the era of big data, the wealth of datasets available in the public domain can be used to underpin proof of concept studies evaluating the biomolecular pathways implicated in chemotherapy resistance in breast cancer.

Identifying a Novel Endoplasmic Reticulum-Related Prognostic Model for Hepatocellular Carcinomas

From the standpoint of the ER (endoplasmic reticulum), we were interested in identifying hub genes that impact clinical prognosis for HCC (hepatocellular carcinoma) patients and developing an ER-related prognostic model. Using TCGA-LIHC (The Cancer Genome Atlas-Liver Hepatocellular Carcinoma) and GSE14520 datasets, we conducted a series of analyses, which included differential gene screening, clinical prognostic analysis, Lasso regression, nomogram prediction, tumour clustering, gene functional enrichment, and tumour infiltration of immune cells. Following our screening for ER-related genes ( $n=1975$ ), we conducted a Lasso regression model to obtain five hub genes, KPNA2, FMO3, SPP1, KIF2C, and LPCAT1, using TCGA-LIHC as a training set. According to risk scores, HCC samples within either the TCGG-LIHC or GSE14520 cohort were categorized into high- and low-risk groups. Compared to the high-risk group of HCC patients, patients in the low-risk group had a better prognosis of OS (overall survival) or RFS (relapse-free survival). For TCGA-LIHC training set, with the factors of risk score, stage, age, and sex, we plotted a nomogram for 1-, 3-, and 5-year survival predictions. Our model demonstrated better clinical validity in both TCGA-LIHC and GSE14520 cohorts. Additionally, events related to biological enzyme activity, biological metabolic processes, or the cell cycle were associated with the prognostic risk of ER. Furthermore, two HCC prognosis-associated tumour clusters were identified by ER hub gene-based consensus clustering. Our findings indicated a link between ER prognostic signature-related high/low risk and tumour infiltration levels of several immune cells, such as “macrophages M2/M0” and “regulatory T cells (Tregs).” Overall, we developed a novel ER-related clinical prognostic model for HCC patients.

Metabolic Rewiring in Glioblastoma Cancer: EGFR, IDH and Beyond

Glioblastoma multiforme (GBM), a highly invasive and incurable tumor, is the humans’ foremost, commonest, and deadliest brain cancer. As in other cancers, distinct combinations of genetic alterations (GA) in GBM induce a diversity of metabolic phenotypes resulting in enhanced malignancy and altered sensitivity to current therapies. Furthermore, GA as a hallmark of cancer, dysregulated cell metabolism in GBM has been recently linked to the acquired GA. Indeed, Numerous point mutations and copy number variations have been shown to drive glioma cells’ metabolic state, affecting tumor growth and patient outcomes. Among the most common, IDH mutations, EGFR amplification, mutation, PTEN loss, and MGMT promoter mutation have emerged as key patterns associated with upregulated glycolysis and OXPHOS glutamine addiction and altered lipid metabolism in GBM. Therefore, current Advances in cancer genetic and metabolic profiling have yielded mechanistic insights into the metabolism rewiring of GBM and provided potential avenues for improved therapeutic modalities. Accordingly, actionable metabolic dependencies are currently used to design new treatments for patients with glioblastoma. Herein, we capture the current knowledge of genetic alterations in GBM, provide a detailed understanding of the alterations in metabolic pathways, and discuss their relevance in GBM therapy.

Overexpression of Karyopherin α2 in small cell carcinoma of the cervix correlates with poor prognosis

BACKGROUND

Cervical small cell carcinoma (SCCC) is uncommon and little is known about its molecular markers. Karyopherin α2 (KPNA2) has been demonstrated in a variety of malignancies. Our objective was to determine whether the KPNA2 level is predictive of clinical outcome in patients with SCCC.

METHODS

We detected KPNA2 expression by immunohistochemistry in SCCC tumors from 62 patients. The staining results were evaluated by H-score. The correlation among KPNA2 expression level, clinical characteristics, and prognosis was analyzed.

RESULTS

KPNA2 expression was detected in tumor tissue from 55 patients with SCCC (55/62, 89%). High KPNA2 expression correlated significantly with International Federation of Gynecology and Obstetrics staging (P=0.035), tumor size (P=0.019), poorer overall survival (OS) (P=0.008), and poorer disease-free survival (P=0.004) compared to low KPNA2 expression. Multivariate analysis showed that KPNA2 expression level (P=0.037) and tumor size (P=0.046) were independent prognostic factors of OS.

CONCLUSIONS

KPNA2 may be a molecular marker and indicator of prognosis in SCCC.

The interaction between S100A2 and KPNA2 mediates NFYA nuclear import and is a novel therapeutic target for colorectal cancer metastasis

Nucleocytoplasmic transport of proteins is disrupted and dysregulated in cancer cells. Nuclear pore complexes and cargo proteins are two main transportation regulators. However, the mechanism regulating nucleocytoplasmic transport in cancer remains elusive. Here, we identified a S100A2/KPNA2 cotransport complex that transports the tumor-associated transcription factor NFYA in colorectal cancer (CRC). Through the S100A2/KNPA2 complex, depending on its interaction with S100A2, NFYA is transported to the nucleus and inhibits the transcriptional activity of E-cadherin, which in turn promotes CRC metastasis. Targeting the S100A2/KPNA2 binding sites with the specific inhibitor delanzomib is a potential therapeutic approach for CRC.

BBOX1-AS1 Accelerates Nasopharyngeal Carcinoma Progression by Sponging miR-3940-3p and Enhancing KPNA2 Upregulation

Background

Upregulation of lncRNA BBOX1 antisense RNA 1 (BBOX1-AS1) has been examined in various tumors. However, its role in nasopharyngeal carcinoma (NPC) remains poorly understood.

Methods

RT-qPCR was performed to measure the expression of BBOX1-AS1, KPNA2, and miR-3940-3p. In vitro assays were performed to determine the alteration of cell phenotypes in NPC cells upon transfection or co-transfection with sh-BBOX1-AS1, sh-KPNA2, or miR-3940-3p inhibitor. The BBOX1-AS1-miR-3940-3p and miR-3940-3p-KPNA2 interplay was verified via luciferase reporter and RNA pull-down assays.

Results

High BBOX1-AS1 levels were detected in the nasopharyngeal carcinoma tissues. BBOX1-AS1 silencing considerably suppressed the proliferative, migratory, and invasive abilities of NPC cells in vitro. Interestingly, BBOX1-AS1 could specifically bind to miR-3940-3 and abrogate the inhibition of KPNA2 induced by miR-3940-3. Additionally, analysis of tissue samples showed that miR-3940-3 was inversely correlated with BBOX1-AS1 and KPNA2.

Conclusion

Our findings revealed that the BBOX1-AS1/miR-3940-3/KPNA2 axis is pro-oncogenic in NPC progression, uncovering novel insights into targeted therapy for this disorder.

HIF-1α-activated long non-coding RNA KDM4A-AS1 promotes hepatocellular carcinoma progression via the miR-411-5p/KPNA2/AKT pathway

Hepatocellular carcinoma (HCC) is the most common type of liver cancer with poor clinical outcomes. Long non-coding RNAs (lncRNAs) are extensively involved in the tumorigenesis and progression of HCC. However, more investigations should be carried out on novel lncRNAs and their effects on HCC. Here we identified a novel lncRNA KDM4A-AS1, which was aberrantly overexpressed in HCC tissues, associated with unfavorable clinical features and poor prognosis of patients. KDM4A-AS1 promoted HCC cell proliferation, migration, and invasion in vitro and contributed to HCC growth and lung metastasis in vivo. Mechanistically, KDM4A-AS1 was inversely modulated by miR-411-5p at the post-transcriptional level and facilitated Karyopherin α2 (KPNA2) expression by competitively binding miR-411-5p, thereby activating the AKT pathway. KPNA2 silencing, miR-411-5p overexpression, and AKT inhibitor (MK2206) consistently reversed KDM4A-AS1-enhanced proliferation, mobility, and EMT of HCC cells. KDM4A-AS1 was identified as a novel hypoxia-responsive gene and transactivated by hypoxia-inducible factor 1α (HIF-1α) in HCC cells. In turn, KDM4A-AS1 regulated HIF-1α expression through the KPNA2/AKT signaling pathway. Hence, this study revealed a novel hypoxia-responsive lncRNA, KDM4A-AS1, which contributed to HCC growth and metastasis via the KDM4A-AS1/KPNA2/HIF-1α signaling loop. Our findings provide a promising prognostic and therapeutic target for HCC.

Increased Nuclear Transporter Importin 7 Contributes to the Tumor Growth and Correlates With CD8 T Cell Infiltration in Cervical Cancer

Background: Importin 7 (IPO7), a karyopherin-β protein, is involved in various tumorigenesis and progression abilities by mediating the nuclear import of oncoproteins. However, the exact biological functions of IPO7 remain to be further elucidated.

Materials and Methods: TCGA and GEO datasets were used to identify dysregulated expression of IPO7 in various cancers. Gain-of-function and loss-of-function analyses were used to identify the oncogenic functions of IPO7 in vitro and in vivo. Moreover, LC-MS/MS and parallel reaction monitoring analysis were used to comparatively profiled IPO7-related proteomics and potential molecular machinery.

Results: Our works demonstrated that the expression of IPO7 was upregulated and was correlated with a poor prognosis in cervical cancer. In vitro and in vivo experiments demonstrated that knockdown of IPO7 inhibited the proliferation of HeLa and C-4 I cells. LC-MS/MS analysis showed that IPO7-related cargo proteins mainly were enriched in gene transcription regulation. Then independent PRM analysis for the first time demonstrated that 32 novel IPO7 cargo proteins, such as GTF2I, RORC1, PSPC1, and RBM25. Moreover, IPO7 contributed to activating the PI3K/AKT-mTOR pathway by mediating the nuclear import of GTF2I in cervical cancer cells. Intriguingly, we found that the IPO7 expression was negatively correlated with CD8 T cell infiltration via regulating the expression of CD276 in cervical cancer.

Conclusion: This study enhances our understanding of IPO7 nuclear-cytoplasmic translocation and might reveal novel potential therapeutic targets. The results of a negative correlation between the IPO7 and CD8 T cell infiltration indicate that the IPO7 might play an important impact on the immune microenvironment of cervical cancer.

Centromere Protein A (CENPA) Regulates Metabolic Reprogramming in the Colon Cancer Cells by Transcriptionally Activating Karyopherin Subunit Alpha 2 (KPNA2)

The karyopherin α₂ subunit gene (KPNA2) has been reported as an oncogene and is involved in metabolic reprogramming in cancer. This study aimed to explore the function of KPNα₂ in the growth and glycolysis in colon cancer (CC) cells. Genes from the Oncomine database that were differentially expressed in multiple CC types were screened. Bioinformatics analysis suggested that KPNA2 was highly expressed in CC: High expression of KPNA2 was detected in the CC cell lines. Down-regulation of KPNA2 reduced viability and DNA-replication ability, and it increased apoptosis of HCT116 and LoVo cells. It also reduced glucose consumption, extracellular acidification rate, and the ATP production in cells. Centromere protein A (CENPA) was confirmed as an upstream transcription activator of KPNA2. There was significant H3K27ac modification in the promoter region of KPNA2. CENPA mainly recruited histone acetyltransferase general control of amino acid synthesis (GCN)-5 to the promoter region of KPNA2 to induce transcription activation. Overexpression of either CENPA or GCN-5 blocked the role of short hairpin KPNα₂ and restored growth and glycolysis in CC cells. To conclude, the findings from this study suggest that CENPA recruits GCN-5 to the promoter region of KPNA2 to induce KPNα₂ activation, which strengthens growth and glycolysis in, and augments the development of, CC.

Rapid reprogramming of tumour cells into cancer stem cells on double-network hydrogels

Cancer recurrence can arise owing to rare circulating cancer stem cells (CSCs) that are resistant to chemotherapies and radiotherapies. Here, we show that a double-network hydrogel can rapidly reprogramme differentiated cancer cells into CSCs. Spheroids expressing elevated levels of the stemness genes Sox2, Oct3/4 and Nanog formed within 24 h of seeding the gel with cells from any of six human cancer cell lines or with brain cancer cells resected from patients with glioblastoma. Human brain cancer cells cultured on the double-network hydrogel and intracranially injected in immunodeficient mice led to higher tumorigenicity than brain cancer cells cultured on single-network gels. We also show that the double-network gel induced the phosphorylation of tyrosine kinases, that gel-induced CSCs from primary brain cancer cells were eradicated by an inhibitor of the platelet-derived growth factor receptor, and that calcium channel receptors and the protein osteopontin were essential for the regulation of gel-mediated induction of stemness in brain cancer cells.

Glutamate-Oxaloacetate Transaminase 1 Impairs Glycolysis by Interacting with Pyruvate Carboxylase and Further Inhibits the Malignant Phenotypes of Glioblastoma Cells

BACKGROUND

Glycolysis is an important metabolic manner in glioblastoma multiforme (GBM)'s rapid growth. It has been reported that glutamate-oxaloacetate transaminase 1 (GOT1) is low-expressed in GBM and patients with high-expressed GOT1 have better prognosis. However, the effect and mechanism of GOT1 on glycolysis and malignant phenotypes of GBM cells are still unclear.

METHODS

The expression differences of GOT1 between GBM parenchyma and adjacent tissues were detected. The prognosis and clinical data with different levels of GOT1 were also analyzed. The glucose consumption, production of lactate and pyruvate were measured after GOT1 was knocked down or overexpressed. The effects of GOT1 on GBM cell's malignant phenotypes were analyzed by Western blot, CCK-8 assay, and flow cytometry. The relationship between GOT1 and pyruvate carboxylase (PC) was examined by immunoprecipitation and immunofluorescence.

RESULTS

GOT1 was expressed little in GBM, and patients with highly expressed GOT1 had longer survival periods. Overexpressed GOT1 inhibited the glycolysis and malignant phenotypes of GBM cells. 2-DG treatment could partially reverse the enhancement of malignant phenotypes caused by knockdown of GOT1. The expression of GOT1 was positively correlated with PC. The inhibitory effect of GOT1 on glycolysis could be partially reversed by PC's knockdown.

CONCLUSIONS

GOT1 could impair glycolysis by interacting with PC and further inhibit the malignant phenotypes of GBM cells.

Dual role of microRNA-1297 in the suppression and progression of human malignancies

MicroRNAs (miRNAs) are endogenous, non-coding, single-stranded and tiny RNAs that modulate several biological functions, more importantly, the pathophysiology of numerous human cancers. They are bound with target mRNAs and thereby regulate gene expression at post-transcriptional levels. MiRNAs can either trigger cancer progression as an oncogene or alleviate it as a tumor suppressor. Abnormal expression of microRNA-1297 (miR-1297) has been noticed in several human cancers suggesting a distinct role for the miRNA in tumorigenesis. More specifically, it is both up-regulated and down-regulated in various cancers suggesting that it can act as both tumor suppressor and oncogene. This review systematically highlights the different roles of miR-1297 in the pathophysiology of human cancers, explains the mechanisms underlying miR-1297-mediated tumorigenesis, and discusses its potential prognostic, diagnostic, and therapeutic importance.

Knockdown of circBFAR inhibits proliferation and glycolysis in gastric cancer by sponging miR-513a-3p/hexokinase 2 axis

The relationship between circular RNAs (circRNAs) and many types of cancer has been of great interest. A novel circRNA, circBFAR, has been identified, but the functions of circBFAR and its underlying mechanism in gastric cancer (GC) have not been reported. This study was designed to investigate the role of circBFAR in GC and its downstream miRNA targets. Quantitative real-time polymerase reaction was used to detect the expression of circBFAR and miRNAs. Cell counting kit-8 and EdU were used to detect the proliferation of GC cells. Measurement of the extracellular acidification rate, oxygen consumption rate and lactate acid production were performed to assess the glycolysis levels. The results showed that circBFAR exhibited higher expression in GC tissues and cell lines. circBFAR was proven to promote GC proliferation by targeting the miR-513a-3p/hexokinase 2 (HK2) axis. Inhibition of circBFAR also led to a significant decrease in the glycolysis levels. In this study, we found a circBFAR/miR-513a-3p/HK2 axis in GC and revealed the relationship between circBFAR and glycolysis for the first time. circBFAR may serve as a novel target of GC individualized therapy.

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.

TNPO1-mediated nuclear import of ARID1B promotes tumor growth in ARID1A-deficient gynecologic cancer

Karyopherin-β proteins are critically involved in cancer progression and have been reported as potential biomarkers and therapeutic targets for tumor treatment. However, TNPO1, as an important karyopherin-β family member, underlying functional roles in cancers remain largely unclear. In this study, under integrated gene-expression profiling screen of karyopherin-β in gynecologic cancer, we identify TNPO1 as a pivotal contributor to the gynecologic cancer progression. Remarkably, ARID1A-deficient gynecologic cancer cells are specifically vulnerable to the genetic perturbations of TNPO1 in vitro and in vivo. Mechanistically, TNPO1 is selectively responsible for nuclear import of ARID1B, which is a synthetic lethal target in ARID1A-inactivating mutation cancers. Furthermore, TNPO1 or ARID1B knockdown changes chromatin accessibility that results in loss of H3K4me1 and H3K27ac marker, diminishing activated transcription factor of the AP-1 family, and inactivating the PI3K/AKT signaling pathway by reducing growth pathway genes expression including PIK3CA and FGFR2. Together, this work indicates that the oncogenic function of TNPO1 and maybe represent a novel therapeutic strategy to treat ARID1A-deficient gynecologic cancer.

C-Myc Signaling Pathway in Treatment and Prevention of Brain Tumors

Brain tumors are responsible for high morbidity and mortality worldwide. Several factors such as the presence of blood-brain barrier (BBB), sensitive location in the brain, and unique biological features challenge the treatment of brain tumors. The conventional drugs are no longer effective in the treatment of brain tumors, and scientists are trying to find novel therapeutics for brain tumors. In this way, identification of molecular pathways can facilitate finding an effective treatment. c-Myc is an oncogene signaling pathway capable of regulation of biological processes such as apoptotic cell death, proliferation, survival, differentiation, and so on. These pleiotropic effects of c-Myc have resulted in much fascination with its role in different cancers, particularly brain tumors. In the present review, we aim to demonstrate the upstream and down-stream mediators of c-Myc in brain tumors such as glioma, glioblastoma, astrocytoma, and medulloblastoma. The capacity of c-Myc as a prognostic factor in brain tumors will be investigated. Our goal is to define an axis in which the c-Myc signaling pathway plays a crucial role and to provide direction for therapeutic targeting in these signaling networks in brain tumors.

Zika virus NS2A protein induces the degradation of KPNA2 (karyopherin subunit alpha 2) via chaperone-mediated autophagy

KPNA2/importin-alpha1 (karyopherin subunit alpha 2) is the primary nucleocytoplasmic transporter for some transcription factors to activate cellular proliferation and differentiation. Aberrant increase of KPNA2 level is identified as a prognostic marker in a variety of cancers. Yet, the turnover mechanism of KPNA2 remains unknown. Here, we demonstrate that KPNA2 is degraded via the chaperone-mediated autophagy (CMA) and that Zika virus (ZIKV) enhances the KPNA2 degradation. KPNA2 contains a CMA motif, which possesses an indispensable residue Gln109 for the CMA-mediated degradation. RNAi-mediated knockdown of LAMP2A, a vital component of the CMA pathway, led to a higher level of KPNA2. Moreover, ZIKV reduced KPNA2 via the viral NS2A protein, which contains an essential residue Thr100 for inducing the CMA-mediated KPNA2 degradation. Notably, mutant ZIKV with T100A alteration in NS2A replicates much weaker than the wild-type virus. Also, knockdown of KPNA2 led to a higher ZIKV viral yield, which indicates that KPNA2 mediates certain antiviral effects. These data provide insights into the KPNA2 turnover and the ZIKV-cell interactions.

A nuclear transport-related gene signature combined with IDH mutation and 1p/19q codeletion better predicts the prognosis of glioma patients

Background

The nuclear transport system has been proposed to be indispensable for cell proliferation and invasion in cancers. Prognostic biomarkers and molecular targets in nuclear transport systems have been developed. However, no systematic analysis of genes related to nuclear transport in gliomas has been performed. An integrated prognostic classification involving mutation and nuclear transport gene signatures has not yet been explored.

Methods

In the present study, we analyzed gliomas from a training cohort (TCGA dataset, n = 660) and validation cohort (CGGA dataset, n = 668) to develop a prognostic nuclear transport gene signature and generate an integrated classification system. Gene set enrichment analysis (GSEA) showed that glioblastoma (GBM) was mainly enriched in nuclear transport progress compared to lower-grade glioma (LGG). Then, we developed a nuclear transport risk score (NTRS) for gliomas with a training cohort. NTRS was significantly correlated with clinical and genetic characteristics, including grade, age, histology, IDH status and 1p/19q codeletion, in the training and validation cohorts.

Results

Survival analysis revealed that patients with a higher NTRS exhibited shorter overall survival. NTRS showed better prognostic value compared to classical molecular markers, including IDH status and 1p/19q codeletion. Furthermore, univariate and multivariate analyses indicated that NTRS was an independent prognostic factor for gliomas. Enrichment map and Gene Ontology analysis demonstrated that signaling pathways related to the cell cycle were enriched in the NTRS^High group. Subgroup survival analysis revealed that NTRS could differentiate the outcomes of low- and high-risk patients with wild-type IDH or mutant IDH and 1p/19q non-codeletion.

Conclusions

NTRS is associated with poor outcomes and could be an independent prognostic marker in diffuse gliomas. Prognostic classification combined with IDH mutation, 1p/19q codeletion and NTRS could better predict the survival of glioma patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12885-020-07552-3.

USP1 Regulates TAZ Protein Stability Through Ubiquitin Modifications in Breast Cancer

Simple Summary

Triple-Negative breast cancer (TNBC) is the most aggressive form of breast cancer in women. Targeted therapies for the treatment of this disease are severely lacking. Through mechanistic studies of the key component of Hippo signaling pathway, Transcriptional co-activator with PDZ-binding motif (TAZ), we aimed to uncover novel regulators that may be used as targeted therapies for this disease. Using an siRNA target deubiquitinating enzymes screen, we identified ubiquitin-specific peptidase 1 (USP1) as a novel TAZ deubiquitinating enzyme. We found that USP1 interacts with TAZ and loss of USP1 reduces cell proliferation in a partially TAZ-dependent manner. Furthermore, we demonstrated that USP1 and TAZ expression are positively correlated in TNBC patients. This research found a newly defined regulatory mechanism of TAZ that could be used as a therapeutic approach for breast cancer.

Abstract

The Hippo signaling pathway is an evolutionarily conserved pathway that was initially discovered in Drosophila melanogaster and was later found to have mammalian orthologues. The key effector proteins in this pathway, YAP/TAZ, are often dysregulated in cancer, leading to a high degree of cell proliferation, migration, metastasis and cancer stem cell populations. Due to these malignant phenotypes it is important to understand the regulation of YAP/TAZ at the protein level. Using an siRNA library screen of deubiquitinating enzymes (DUBs), we identified ubiquitin specific peptidase 1 (USP1) as a novel TAZ (WWTR1) regulator. We demonstrated that USP1 interacts with TAZ and increases TAZ protein stability. Conversely, loss of function of USP1 reduces TAZ protein levels through increased poly-ubiquitination, causing a decrease in cell proliferation and migration of breast cancer cells. Moreover, we showed a strong positive correlation between USP1 and TAZ in breast cancer patients. Our findings facilitate the attainment of better understanding of the crosstalk between these pathways and may lead to potential therapeutic interventions for breast cancer patients.

Development of RNA binding proteins expression signature for prognosis prediction in gastric cancer patients

It was reported that the expression of RNA binding proteins (RBPs) in malignant tumors is dysregulated and is closely related to tumorigenesis. However, some studies have confirmed the role of RBPs in gastric cancer (GC). We obtained data on gastric cancer in The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx), and identified RBPs that are dysregulated between gastric normal and cancer tissues. Then, we systematically investigated the expression characteristics and clinical prognostic potential of these RBPs through bioinformatics methods. We found 278 dysregulated RBPs in the GC, 91 of which were up-regulated and 181 were down-regulated. We detected 4 hub RBPs (HNRNPL, PABPN1, PCF, SNRPN) are related to overall survival (OS), and 3 hub RBPs (EEF1A2, MRPS5, PCF1) are related to disease-specific survival (DSS), and furthermore, we constructed prognostic signatures. Analysis of the OS and DSS signature showed that the GC patients with high-risk groups have worse OS and DSS than the low-risk groups. The receiver operator characteristic (ROC) curves of the 5-year survival rate of OS and DSS prognosis signature were drawn, and the areas under the two curves were 0.62 and 0.64, respectively. We constructed nomograms to predict OS and DSS, and evaluated by the calibration curve, which showed the GC prediction ability of these two models. Furthermore, the expression of the above six genes was verified by PCR, which is consistent with our results.

Emerging Roles and Therapeutic Interventions of Aerobic Glycolysis in Glioma

Glioma is the most common type of intracranial malignant tumor, with a great recurrence rate due to its infiltrative growth, treatment resistance, intra- and intertumoral genetic heterogeneity. Recently, accumulating studies have illustrated that activated aerobic glycolysis participated in various cellular and clinical activities of glioma, thus influencing the efficacy of radiotherapy and chemotherapy. However, the glycolytic process is too complicated and ambiguous to serve as a novel therapy for glioma. In this review, we generalized the implication of key enzymes, glucose transporters (GLUTs), signalings and transcription factors in the glycolytic process of glioma. In addition, we summarized therapeutic interventions via the above aspects and discussed promising clinical applications for glioma.

Tumor Microenvironment Is Critical for the Maintenance of Cellular States Found in Primary Glioblastomas

Glioblastoma (GBM), an incurable tumor, remains difficult to model and more importantly to treat due to its genetic/epigenetic heterogeneity and plasticity across cellular states. The ability of current tumor models to recapitulate the cellular states found in primary tumors remains unexplored. To address this issue, we compared single-cell RNA sequencing of tumor cells from 5 patients across four patient-specific glioblastoma stem cell (GSC)-derived model types, including glioma spheres, tumor organoids, glioblastoma cerebral organoids (GLICO), and patient-derived xenografts. We find that GSCs within the GLICO model are enriched for a neural progenitor-like cell subpopulation and recapitulate the cellular states and their plasticity found in the corresponding primary parental tumors. These data demonstrate how the contribution of a neuroanatomically accurate human microenvironment is critical and sufficient for recapitulating the cellular states found in human primary GBMs, a principle that may likely apply to other tumor models. SIGNIFICANCE: It has been unclear how well different patient-derived GBM models are able to recreate the full heterogeneity of primary tumors. Here, we provide a complete transcriptomic characterization of the major model types. We show that the microenvironment is crucial for recapitulating GSC cellular states, highlighting the importance of tumor-host cell interactions.See related commentary by Luo and Weiss, p. 907.This article is highlighted in the In This Issue feature, p. 890.

The miR-26b-5p/KPNA2 Axis Is an Important Regulator of Burkitt Lymphoma Cell Growth

The expression of several microRNAs (miRNAs) is known to be changed in Burkitt lymphoma (BL), compared to its normal counterparts. Although for some miRNAs, a role in BL was demonstrated, for most of them, their function is unclear. In this study, we aimed to identify miRNAs that control BL cell growth. Two BL cell lines were infected with lentiviral pools containing either 58 miRNA inhibitors or 44 miRNA overexpression constructs. Eighteen constructs showed significant changes in abundance over time, indicating that they affected BL growth. The screening results were validated by individual green fluorescent protein (GFP) growth competition assays for fifteen of the eighteen constructs. For functional follow-up studies, we focused on miR-26b-5p, whose overexpression inhibited BL cell growth. Argonaute 2 RNA immunoprecipitation (Ago2-IP) in two BL cell lines revealed 47 potential target genes of miR-26b-5p. Overlapping the list of putative targets with genes showing a growth repression phenotype in a genome-wide CRISPR/Cas9 knockout screen, revealed eight genes. The top-5 candidates included EZH2, COPS2, KPNA2, MRPL15, and NOL12. EZH2 is a known target of miR-26b-5p, with oncogenic properties in BL. The relevance of the latter four targets was confirmed using sgRNAs targeting these genes in individual GFP growth competition assays. Luciferase reporter assay confirmed binding of miR-26b-5p to the predicted target site for KPNA2, but not to the other genes. In summary, we identified 18 miRNAs that affected BL cell growth in a loss- or gain-of-function screening. A tumor suppressor role was confirmed for miR-26b-5p, and this effect could at least in part be attributed to KPNA2, a known regulator of OCT4, c-jun, and MYC.

Silencing KPNA2 inhibits IL-6-induced breast cancer exacerbation by blocking NF-κB signaling and c-Myc nuclear translocation in vitro

AIMS

Recently, studies indicated that inflammation could exacerbate the development of BC. Karyopherin α-2 (KPNA2) is a molecule which modulates nucleocytoplasmic transport and is involved in malignant cellular behavior and carcinogenesis. Our study aims to elucidate the role of KPNA2 in BC pathogenesis and explore the mechanism of KPNA2 in regulating inflammation-induced BC exacerbations.

MAIN METHODS

We measured the expression of KPNA2 in BC cells. Through loss-of-function experiments, the functional role of KPNA2 in MCF-7 and MDA-MB-468 cells was evaluated. SK-BR-3 cells were treated with IL-6 as an inflammatory in vitro model of BC. ELISA determination exhibited the contents of cytokines. RANKL and leptomycin B treatments activated NF-κB signaling and inhibited the nuclear translocation of c-Myc, respectively.

KEY FINDINGS

The results showed that KPNA2 was significantly up-regulated in BC and silencing KPNA2 inhibited the proliferation, migration and invasion of BC cells, while the cycle arrest was induced, via blocking NF-κB signaling and c-Myc nuclear translocation. IL-6 stimulated the secretions of IL-8 and IL-17 in BC cells, and elevated KPNA2 expression. However, KPNA2 knockdown suppressed the inflammatory responses and malignant progression of BC induced by IL-6.

SIGNIFICANCE

In conclusion, our study illustrated that KPNA2 regulated BC development, as well as IL-6-induced inflammation and exacerbation, via NF-κB signaling and c-Myc nuclear translocation. This may provide a novel target for BC therapy.

Karyopherin α 2 promotes proliferation, migration and invasion through activating NF-κB/p65 signaling pathways in melanoma cells

AIMS

Melanoma is a fatal malignancy. Karyopherin α 2 (KPNA2) plays an important role in many carcinogenesis. This study was aimed to study the role of KPNA2 in cellular functions and molecular mechanisms of melanoma.

MAIN METHODS

We investigated the expression and prognosis of KPNA2 in melanoma using the GEPIA database (http://gepia.cancer-pku.cn/). The effect of KPNA2 on melanoma cells was determined using real-time PCR, western blot, immunofluorescence assay, CCK-8, colony formation, wound healing assay, transwell assay, EMSA, and immunohistochemistry. The influence of KPNA2 on the tumorigenicity of melanoma cells was evaluated in a nude mice model in vivo.

KEY FINDINGS

Our results showed that KPNA2 expression is relatively high in melanoma tissues and cells, and melanoma patients with higher expression of KPNA2 had lower overall survival rate and disease free survival rate. KPNA2 promoted proliferation ability and increased the expression of PCNA, Ki67, and C-MYC in melanoma cells. Further, KPNA2 could promote migration and invasion and increase the expression of MMP2 and MMP9. Mechanism studies showed that KPNA2 activated NF-κB/p65 signaling pathways, as evidenced by the nuclear translocation of p65 and increased the expression of COX-2, ICAM-1, iNOS, and MCP1 in melanoma cells. NF-κB inhibitor JSH-23 could reverse the pro-tumor effects of KPNA2 on melanoma cells. Moreover, upregulation of KPNA2 facilitated the tumorigenicity of melanoma cells.

SIGNIFICANCE

KPNA2 promotes proliferation, migration and invasion through enhancing NF-κB/p65 signaling pathways in melanoma cells. Our study suggests KPNA2 as a potential therapeutic target for the treatment of melanoma.

Overexpression of Karyopherin Subunit alpha 2 (KPNA2) Predicts Unfavorable Prognosis and Promotes Bladder Cancer Tumorigenicity via the P53 Pathway

Background

We sought to investigate the expression of KPNA2 in bladder cancer (BC) and its relationship with prognosis, and to analyze the potential mechanism of KPNA2 in promoting BC progression.

Material/Methods

The RNA-seq data on BC from The Cancer Genome Atlas (TCGA) database were imported into R statistical software for differential analysis. The clinical data for patients with BC were screened and analyzed with R software. The survival curve was drawn with the Kaplan-Meier Plotter. The expression of KPNA2 in 4 human BC cell lines and a human bladder epithelial cell line was detected by quantitative real-time polymerase chain reaction (qRT-PCR) and Western blotting (WB). The proliferation of BC cells was detected with Cell Counting Kit-8 (CCK8), detection of apoptosis, and flow cytometry, and the migration and invasion of BC cells were detected through Transwell assays. WB was used to detect proteins involved in the P53 pathway.

Results

The expression of KPNA2 was higher in BC. The difference in KPNA2 expression was associated with many clinicopathological factors, and high expression of KPNA2 was associated with shorter survival time. After KPNA2 knockout, the proliferation, migration, and invasion ability decreased significantly, the cell cycle was clearly arrested in the G0/G1 phase, and the number of apoptotic cells increased. Moreover, CyclinD1, BCL2, and pro-caspase3 decreased significantly, whereas P53, P21, BAX, and cleaved-caspase3 increased significantly. The results in the overexpression group were the opposite of results in the knockdown group.

Conclusions

KPNA2 is an oncogenic factor that facilitates BC tumorigenicity through the P53 pathway.

MiR-1297 negatively regulates metabolic reprogramming in glioblastoma via repressing KPNA2

Cancer cell growth is characterized by reprogrammed glucose metabolism and subsequent high rate of glycolysis. The metabolic reprogramming is essential for cell proliferation and drug resistance of cancer cells including glioblastoma (GBM). MicroRNAs play pivotal roles during GBM development. In the present study, we discovered a significant downregulation of miR-1297 in GBM. Decreased miR-1297 expression was associated with prolonged overall survival of patients with glioma. Overexpression of miR-1297 promoted cell proliferation and glycolysis in GBM cells. Bioinformatic analysis (TargetScan and miRanda) indicated that miR-1297 might target 3'UTR of KPNA2, a key regulator of glycolysis in GBM. The regulation was confirmed in a dual-luciferase reporter assay in GBM cells. Furthermore, overexpression of KPNA2 could reverse miR-1297 mimic induced cell growth arrest and inhibition of glycolysis in GBM cells. Finally, a negative correlation between miR-1297 and KPNA2 mRNA levels was observed in GBM tissues. Collectively, the data demonstrated that the abnormal metabolic reprogramming was driven by miR-1297 in GBM and suggested miR-1297 as a tumor suppressor.

The emerging roles of KPNA2 in cancer

Karyopherin α2 (KPNA2, also known as importinα-1), a member of the nuclear transporter family, is involved in the nucleocytoplasmic transport pathway of a variety of tumor-associated proteins. Recent studies have found that KPNA2 is overexpressed in various cancers, which is associated with poor prognosis. In addition, it has been shown to promote tumor formation and progression by participating in cell differentiation, proliferation, apoptosis, immune response, and viral infection. It is indicated that KPNA2 also plays an important role in the diagnosis, treatment and prognosis of tumors. Herein, we provide an overview of the function and mechanism of KPNA2 in cancer and the prospects in the diagnosis and treatment of cancer. In the future, KPNA2 provides new ideas for the early diagnosis of malignant tumors, the development of molecularly targeted drugs, and prognosis evaluation.

Silencing of KPNA2 inhibits high glucose-induced podocyte injury via inactivation of mTORC1/p70S6K signaling pathway

Dysregulation of apoptotic and autophagic function are characterized as the main pathogeneses of diabetic nephropathy (DN). It has been reported that Karyopherin Alpha 2 (KPNA2) contributes to apoptosis and autophagy in various cells, but its role in DN development remains unknown. The purpose of present study was to explore the function and underling mechanisms of KPNA2 in development of DN. In this study, 30 mM high glucose (HG)-evoked podocytes were used as DN model. The expression of KPNA2 was detected by qRT-PCR and Western blot assays. The cell viability was tested by CCK-8 kit, the apoptosis was measured using flow cytometry assay, the apoptotic and the autophagy related genes was detected by Western blot. Our results indicated that KPNA2 was significantly increased after HG stimulation. Knockdown of KPNA2 inhibited apoptosis, and promoted cell viability and autophagy in HG-treated podocytes. In addition, silencing of KPNA2 deactivated mTORC1/p70S6K pathway activation via regulating SLC1A5. Further results demonstrated that activating mTORC1/p70S6K pathway strongly ameliorated the effect of KPNA2 on cell viability, apoptosis and autophagy. Therefore, our study suggested that knockdown of KPNA2 rescued HG-induced injury via blocking activation of mTORC1/p70S6K pathway by mediating SLC1A5.

IPO5 promotes the proliferation and tumourigenicity of colorectal cancer cells by mediating RASAL2 nuclear transportation

Background

Karyopherin nuclear transport receptors play important roles in tumour development and drug resistance and have been reported as potential biomarkers and therapeutic targets for tumour treatment. However, IPO5, one of the karyopherin nuclear transport receptor family members, remains largely uncharacterized in tumour progression.

Methods

The TCGA data, quantitative reverse transcription-PCR (qRT-PCR), western blotting, and IHC analyses were used to detect IPO5 expression in CRC tissues. A series of in vivo and in vitro experiments was utilized to demonstrate the function of IPO5 in CRC tissues. Mass spectrometry (MS), CO-IP technology, subcellular fractionation, and immunofluorescence were utilized to investigate the possible mechanisms of CRC.

Results

IPO5 was highly expressed and positively correlated with the clinicopathological characteristics of colorectal cancer tissues. Functional experiments indicated that IPO5 could promote the development of CRC. Mechanistically, we screened RASAL2, one cargo of IPO5, and further confirmed that IPO5 bound to the NLS sequence of RASAL2, mediating RASAL2 nuclear translocation and inducing RAS signal activation, thereby promoting the progression of CRC.

Conclusions

Together, our results indicate that IPO5 is overexpressed in colorectal cancer cells. By transporting RASAL2, IPO5 may play a crucial role in CRC.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1290-0) contains supplementary material, which is available to authorized users.

MicroRNA-524 inhibits the progress of glioma via the direct targeting of NCF2

In recent years, a large amount of research has reported that microRNA (miRNA) dysregulation is closely related to glioma progression. miR-524, a member of the miRNA family, has been confirmed to be involved in many human diseases, including glioma. However, the role and molecular mechanism of miR-524 in glioma have not been clarified. In our study, we showed that miR-524 expression was significantly decreased in glioma and was associated with glioma recurrence. Next, we performed a series of assays and confirmed that the upregulation of miR-524 suppressed glucose uptake, proliferation, migration and invasion in glioma cell lines. Then, through bioinformatics software and a dual luciferase assay, we demonstrated that NCF2 was a target gene of miR-524. In addition, we found that NCF2 reintroduction restored the inhibitor effect of miR-524 on glioma progression. These results elucidate the mechanism of miR-524 in glioma development and provide a potential therapeutic strategy for glioma patients.

Recent advances in searching c-Myc transcriptional cofactors during tumorigenesis

Background

The mechanism by which c-Myc exerts its oncogenic functions is not completely clear and different hypotheses are still under investigation. The knowledge of the capacity of c-Myc to bind exclusively E-box sequences determined the discrepancy between, on the one hand, genomic studies showing the binding of c-Myc to all active promoters and, on the other hand, the evidence that only 60% or less of the binding sites have E-box sequences.

Main body

In this review, we provide support to the hypothesis that the cooperation of c-Myc with transcriptional cofactors mediates c-Myc-induced cellular functions. We produce evidence that recently identified cofactors are involved in c-Myc control of survival mechanisms of cancer cells.

Conclusion

The identification of new c-Myc cofactors could favor the development of therapeutic strategies able to compensate the difficulty of targeting c-Myc.