E2F1 and E2F7 differentially regulate KPNA2 to promote the development of gallbladder cancer

GPRC5A promotes gallbladder cancer metastasis by upregulating TNS4 via the JAK2-STAT3 pathway

Aberrant expression of G protein-coupled receptor class C group 5 member A (GPRC5A) has been reported in multiple cancers and is closely related to patient prognosis. However, the mechanistic role of GPRC5A in gallbladder cancer (GBC) remains unclear. Here, we determined tumor expression levels of GPRC5A and the molecular mechanisms by which GPRC5A regulates gallbladder cancer metastasis. We found that GPRC5A was significantly upregulated in GBC, correlating with poorer patient survival. Knocking down GPRC5A inhibited GBC cell metastasis both in vitro and in vivo. GRPRC5A knockdown resulted in downregulation of TNS4 expression through the JAK2-STAT3 axis. Clinically, GPRC5A expression positively correlated with TNS4. Finally, STAT3 bound to TNS4's promoter region, inducing its expression. Overall, GPRC5A showed high expression in GBC tissues, associated with poor patient prognosis. Our findings first demonstrate that the GPRC5A-JAK2-STAT3-TNS4 pathway promotes GBC cell metastasis, suggesting potential therapy targets.

KPNA2 promotes the progression of gastric cancer by regulating the alternative splicing of related genes

RNA-binding proteins (RBPs) play critical roles in genome regulation. In this study, we explored the latent function of KPNA2, which is an essential member of the RBP family, in the regulation of alternative splicing (AS) in gastric cancer (GC). We analyzed the role of KPNA2 in regulating differential expression and AS via RNA sequencing (RNA-seq) and improved RNA immunoprecipitation sequencing (iRIP-seq). Clinical specimens were used to analyze the associations between KPNA2 expression and clinicopathological characteristics. CCK8 assays, transwell assays and wound healing assays were performed to explore the effect of KPNA2/WDR62 on GC cell progression. KPNA2 was shown to be highly expressed in GC cells and tissues and associated with lymph node metastases. KPNA2 promoted the proliferation, migration and invasion of GC cells and primarily regulated exon skipping, alternative 3's splice sites (A3SSs), alternative 5' splice sites (A5SSs), and cassette exons. We further revealed that KPNA2 participated in biological processes related to cell proliferation, and the immune response in GC via the regulation of transcription. In addition, KPNA2 preferentially bound to intron regions. Notably, KPNA2 regulated the A3SS AS mode of WDR62, and upregulation of WDR62 reversed the KPNA2 downregulation-induced inhibition of GC cell proliferation, migration and invasion. Finally, we discovered that the AS of immune-related molecules could be regulated by KPNA2. Overall, our results demonstrated for the first time that KPNA2 functions as an oncogenic splicing factor in GC that regulated the AS and differential expression of GC-related genes, and KPNA2 may be a potential target for GC treatment.

Proteomic profiling improves prognostic risk stratification of the Sarculator nomogram in soft tissue sarcomas of the extremities and trunk wall

BACKGROUND

High-risk soft tissue sarcomas of the extremities and trunk wall (eSTS), as defined by the Sarculator nomogram, are more likely to benefit from (neo)adjuvant anthracycline-based therapy compared to low/intermediate-risk patients. The biology underpinning these differential treatment outcomes remain unknown.

METHODS

We analysed proteomic profiles and clinical outcomes of 123 eSTS patients. A Cox model for overall survival including the Sarculator was fitted to individual data to define four risk groups. A DNA replication protein signature-Sarcoma Proteomic Module 6 (SPM6) was evaluated for association with clinicopathological factors and risk groups. SPM6 was added as a covariate together with Sarculator in a multivariable Cox model to assess improvement in prognostic risk stratification.

RESULTS

DNA replication and cell cycle proteins were upregulated in high-risk versus very low-risk patients. Evaluation of the functional effects of CRISPR-Cas9 gene knockdown of proteins enriched in high-risk patients using the cancer cell line encyclopaedia database identified candidate drug targets. SPM6 was significantly associated with tumour malignancy grade (p = 1.6e-06), histology (p = 1.4e-05) and risk groups (p = 2.6e-06). Cox model analysis showed that SPM6 substantially contributed to a better calibration of the Sarculator nomogram (Index of Prediction Accuracy = 0.109 for Sarculator alone versus 0.165 for Sarculator + SPM6).

CONCLUSIONS

Risk stratification of patient with STS is defined by distinct biological pathways across a range of cancer hallmarks. Incorporation of SPM6 protein signature improves prognostic risk stratification of the Sarculator nomogram. This study highlights the utility of integrating protein signatures for the development of next-generation nomograms.

New link between RNH1 and E2F1: regulates the development of lung adenocarcinoma

BACKGROUND

Lung adenocarcinoma (LUAD) is a non-small cell carcinoma. Ribonuclease/angiogenin inhibitor 1 (RNH1) exerts multiple roles in virous cancers. E2F1 is a critical transcription factor involved in the LUAD development. Here, we analyze the expression of RNH1 in LUAD patients, investigate the biological function of RNH1 in LUAD, and demonstrate its potential mechanisms through E2F1 in LUAD.

METHODS

In the present study, we presented the expression of RNH1 in LUAD based on the database and confirmed it by western blot detection of RNH1 in human LUAD tissues. Lentiviral infection was constructed to silence or overexpress RNH1 in NCI-H1395 and NCI-H1437 cells. We assess the role of RNH1 on proliferation in LUAD cells by MTT assay, colony formation assays, and cell cycle detection. Hoechst staining and flow cytometry were used to evaluate the effects of RNH1 on apoptosis of LUAD cells. The function of RNH1 in invasion and migration was investigated by Transwell assay. Dual luciferase assay, ChIP detection, and pull-down assay were conducted to explore the association of E2F1 in the maintenance of RNH1 expression and function. The regulation of E2F1 on the functions of RNH1 in LUAD cells was explored. Mouse experiments were performed to confirm the in-vivo role of RNH1 in LUAD. mRNA sequencing indicated that RNH1 overexpression altered the expression profile of LUAD cells.

RESULTS

RNH1 expression in LUAD tissues of patients was presented in this work. Importantly, RNH1 knockdown improved the proliferation, migration and invasion abilities of cells and RNH1 overexpression produced the opposite effects. Dual luciferase assay proved that E2F1 bound to the RNH1 promoter (-1064 ∼ -1054, -1514 ∼ -1504) to reduce the transcriptional activity of RNH1. ChIP assay indicated that E2F1 DNA was enriched at the RNH1 promoter (-1148 ∼ -943, -1628 ∼ -1423). Pull-down assays also showed the association between E2F1 and RNH1 promoter (-1148 ∼ -943). E2F1 overexpression contributed to the malignant behavior of LUAD cells, while RNH1 overexpression reversed it. High-throughput sequencing showed that RNH1 overexpression induced multiple genes expression changes, thereby modulating LUAD-related processes.

CONCLUSION

Our study demonstrates that binding of E2F1 to the RNH1 promoter may lead to inhibition of RNH1 expression and thus promoting the development of LUAD.

NONO promotes gallbladder cancer cell proliferation by enhancing oncogenic RNA splicing of DLG1 through interaction with IGF2BP3/RBM14

Gallbladder cancer (GBC) is a highly malignant and rapidly progressing tumor of the human biliary system, and there is an urgent need to develop new therapeutic targets and modalities. Non-POU domain-containing octamer-binding protein (NONO) is an RNA-binding protein involved in the regulation of transcription, mRNA splicing, and DNA repair. NONO expression is elevated in multiple tumors and can act as an oncogene to promote tumor progression. Here, we found that NONO was highly expressed in GBC and promoted tumor cells growth. The dysregulation of RNA splicing is a molecular feature of almost all tumor types. Accordingly, mRNA-seq and RIP-seq analysis showed that NONO promoted exon6 skipping in DLG1, forming two isomers (DLG1-FL and DLG1-S). Furthermore, lower Percent-Spliced-In (PSI) values of DLG1 were detected in tumor tissue relative to the paraneoplastic tissue, and were associated with poor patient prognosis. Moreover, DLG1-S and DLG1-FL act as tumor promoters and tumor suppressors, respectively, by regulating the YAP1/JUN pathway. N6-methyladenosine (m6A) is the most common and abundant RNA modification involved in alternative splicing processes. We identified an m6A reader, IGF2BP3, which synergizes with NONO to promote exon6 skipping in DLG1 in an m6A-dependent manner. Furthermore, IP/MS results showed that RBM14 was bound to NONO and interfered with NONO-mediated exon6 skipping of DLG1. In addition, IGF2BP3 disrupted the binding of RBM14 to NONO. Overall, our data elucidate the molecular mechanism by which NONO promotes DLG1 exon skipping, providing a basis for new therapeutic targets in GBC treatment.

Acylcarnitines promote gallbladder cancer metastasis through lncBCL2L11-THOC5-JNK axis

BACKGROUND

The progression of gallbladder cancer (GBC) is accompanied by abnormal fatty acid β-oxidation (FAO) metabolism. Different types of lipids perform various biological functions. This study aimed to determine the role of acyl carnitines in the molecular mechanisms of GBC progression.

METHODS

Distribution of lipids in GBC was described by LC-MS-based lipidomics. Cellular localization, expression level and full-length of lncBCL2L11 were detected using fluorescence in situ hybridization (FISH) assays, subcellular fractionation assay and 5' and 3' rapid amplification of the cDNA ends (RACE), respectively. In vitro and in vivo experiments were used to verify the biological function of lncBCL2L11 in GBC cells. Methylated RNA Immunoprecipitation (MeRIP) was performed to detect the methylation levels of lncBCL2L11. RNA pull-down assay and RNA immunoprecipitation (RIP) assay were used to identify lncBCL2L11 interacting proteins. Co-Immunoprecipitation (Co-IP) and Western blot assay were performed to validate the regulatory mechanism of lncBCL2L11 and THO complex.

RESULTS

Acylcarnitines were significantly up-regulated in GBC tissues. High serum triglycerides correlated to decreased survival in GBC patients and promoted tumor migration. LncBCL2L11 was identified in the joint analysis of highly metastatic cells and RNA sequencing data. LncBCl2L11 prevented the binding of THOC6 and THOC5 and causes the degradation of THOC5, thus promoting the accumulation of acylcarnitines in GBC cells, leading to the malignant progression of cancer cells. In addition, highly expressed acylcarnitines stabilized the expression of lncBCL2L11 through N6-methyladenosine methylation (m6A), forming a positive feedback regulation in tumor dissemination.

CONCLUSIONS

LncBCL2L11 is involved in gallbladder cancer metastasis through FAO metabolism. High lipid intake is associated with poor prognosis of GBC. Therefore, targeting lncBCL2L11 and its pathway-related proteins or reducing lipid intake may be significant for the treatment of GBC patients.

Role of E2F transcription factor in Oral cancer: Recent Insight and Advancements

The family of mammalian E2F transcription factors (E2Fs) comprise of 8 members (E2F1-E2F8) classified as activators (E2F1-E2F3) and repressors (E2F4-E2F8) primarily regulating the expression of several genes related to cell proliferation, apoptosis and differentiation, mainly in a cell cycle-dependent manner. E2F activity is frequently controlled via the retinoblastoma protein (pRb), cyclins, p53 and the ubiquitin-proteasome pathway. Additionally, genetic or epigenetic changes result in the deregulation of E2F family genes expression altering S phase entry and apoptosis, an important hallmark for the onset and development of cancer. Although studies reveal E2Fs to be involved in several human malignancies, the mechanisms underlying the role of E2Fs in oral cancer lies nascent and needs further investigations. This review focuses on the role of E2Fs in oral cancer and the etiological factors regulating E2Fs activity, which in turn transcriptionally control the expression of their target genes, thus contributing to cell proliferation, metastasis, and drug/therapy resistance. Further, we will discuss therapeutic strategies for E2Fs, which may prevent oral tumor growth, metastasis, and drug resistance.

Hsa-miR-195-5p Inhibits Autophagy and Gemcitabine Resistance of Lung Adenocarcinoma Cells via E2F7/CEP55

Lung adenocarcinoma (LUAD) is a common malignancy. Many studies have shown that LUAD is resistant to gemcitabine chemotherapy, resulting in poor treatment outcomes in patients. We designed this study to reveal influences of hsa-miR-195-5p/E2F7/CEP55 axis on gemcitabine resistance and autophagy of LUAD cells. The expression data of LUAD-related mRNAs were downloaded from TCGA-LUAD database for differential expression analysis. The bioinformatics databases (hTFtarget, starBase and TargetScan) were used to predict the upstream and downstream regulatory molecules of E2F7. Then the binding relationships between E2F7 and regulatory molecules were verified by ChIP and dual-luciferase reporter assay. qRT-PCR and western blot were used to detect the mRNA and protein levels of has-miR-195-5p, E2F7, and CEP55. CCK-8 assay was used to analyze the half-maximal inhibitory concentration (IC₅₀) and cell proliferation ability of LUAD cells after gemcitabine treatment. Apoptosis was detected by flow cytometry. Apoptosis/autophagy markers and LC3 aggregation were detected by western blot and immunofluorescence, respectively. Finally, the mouse transplantation model was constructed to verify the regulation mechanism in vivo. In LUAD cells and tissues, E2F7 and CEP55 were highly expressed, while has-miR-195-5p was relatively less expressed. The ChIP or dual-luciferase assays demonstrated the binding relationships of E2F7 to the CEP55 promoter region and has-miR-195-5p to the 3'-UTR of E2F7. Cell experiments demonstrated that overexpression of hsa-miR-195-5p stimulated LUAD cell apoptosis and inhibited autophagy and gemcitabine resistance, while further overexpression E2F7/CEP55 could reverse the impact by hsa-miR-195-5p overexpression. In vivo experiments identified that hsa-miR-195-5p/E2F7/CEP55 axis constrained the growth of LUAD tumor. Hsa-miR-195-5p promoted apoptosis, repressed proliferation, and autophagy via E2F7/CEP55 and reduced gemcitabine resistance in LUAD, indicating that hsa-miR-195-5p/E2F7/CEP55 may be a novel target for LUAD.

Comprehensive analysis to identify the RP11-478C19.2/ E2F7 axis as a novel biomarker for treatment decisions in clear cell renal cell carcinoma

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LncRNA RP11–478C19.2 promotes the progression of ccRCC via the RP11–478C19.2/hsa-miR-181b-5p, hsa-miR-181a-5p, hsa-miR-181c-5p/E2F7 axis.

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E2F7 could be detected in patients with ccRCC to aid treatment regimen selection, particularly in advanced and metastatic disease.

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Individuals who overexpress E2F7 may have a greater response to some first-line therapy for ccRCC, including cabozantinib, pazopanib, and sunitinib.

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Patients with higher expression of E2F7 may have a higher percentage of ICB responses.

Clear cell renal cell carcinoma (ccRCC), accounting for 70–80% of all renal cell carcinomas, is a common malignancy. Survival rates decrease significantly in patients with advanced and metastatic ccRCC. Furthermore, ccRCC is less responsive to radiation and chemotherapy than other cancers. Therefore, targeted therapy and immunotherapy are particularly important for ccRCC management. A growing body of literature recognizes that competitive endogenous RNA (ceRNA) regulatory networks play a crucial role in various cancers. However, the biological functions of the ceRNA network in ccRCC require further investigation. In this study, we built the ceRNA network for ccRCC using the “GDCRNATools” package. After survival analysis, the RP11–478C19.2/hsa-miR-181b-5p, hsa-miR-181a-5p, and hsa-miR-181c-5p/E2F7 axes were obtained for further analysis. Unsupervised clustering was conducted basing on this ceRNA network. The results indicated that the prognosis and immune infiltration levels differed between the two clusters. Furthermore, we conducted correlation analysis, immune infiltration analysis, tumor mutation burden analysis, GSEA analysis, drug sensitivity analysis and pan-cancer analysis of E2F7 to explore its potential role in oncogenesis. Experiments in vitro were performed to confirm the pro-oncogenic impact of E2F7. The results suggest that the RP11–478C19.2/E2F7 axis might be a biomarker for the inclusion of cabozantinib, pazopanib, sunitinib, and immunotherapy in the therapeutic regimen. In summary, we found that the ceRNA-based RP11–478C19.2/E2F7 axis is involved in ccRCC and that it could be a novel biomarker for treatment decisions and a possible therapeutic target to increase the success of targeted therapy and immunotherapy in ccRCC.

The miR-532-E2F1 feedback loop contributes to gastric cancer progression

Gastric cancer (GC) ranks fourth in incidence and mortality worldwide, ascertaining the pathogenesis of GC is crucial for its treatment. E2F1, which regulates the transcription of genes encoding proteins involved in DNA repair, DNA replication, mitosis and survival of cancer patients, functions as a key regulator in GC progression. However, the underneath mechanism of these processes is not fully elucidated. Here, TCGA database analysis, microarray immunohistochemical technique and western blot showed that E2F1 was highly upregulated in clinical GC tissues and correlated with tumor malignancy. In vitro and in vivo assays confirmed the oncogenic function of E2F1. MiR-532 was decreased and negatively correlated with E2F1 in GC tissues. MiR-532 directly targeted and inhibited E2F1 expression, leading to the decrease of ASK1 and elevation of TXNIP, and affected proliferation, cell cycle, apoptosis and DNA damage in vitro and tumor growth in vivo. Moreover, E2F1 serves as a transcriptional repressor to suppress miR-532 expression and a double-negative feedback loop was formed between them. This study demonstrates the significant roles of the E2F1-miR-532 double-negative feedback loop in GC progression and may represent a potential target for GC therapy.

SAPCD2 promotes neuroblastoma progression by altering the subcellular distribution of E2F7

Recent studies uncovered the emerging roles of SAPCD2 (suppressor anaphase-promoting complex domain containing 2) in several types of human cancer. However, the functions and underlying mechanisms of SAPCD2 in the progression of neuroblastoma (NB) remain elusive. Herein, through integrative analysis of public datasets and regulatory network of GSK-J4, a small-molecule drug with anti-NB activity, we identified SAPCD2 as an appealing target with a high connection to poor prognosis in NB. SAPCD2 promoted NB progression in vitro and in vivo. Mechanistically, SAPCD2 could directly bind to cytoplasmic E2F7 but not E2F1, alter the subcellular distribution of E2F7 and regulate E2F activity. Among the E2F family members, the roles of E2F7 in NB are poorly understood. We found that an increasing level of nuclear E2F7 was induced by SAPCD2 knockdown, thereby affecting the expression of genes involved in the cell cycle and chromosome instability. In addition, Selinexor (KTP-330), a clinically available inhibitor of exportin 1 (XPO1), could induce nuclear accumulation of E2F7 and suppress the growth of NB. Overall, our studies suggested a previously unrecognized role of SAPCD2 in the E2F signaling pathway and a potential therapeutic approach for NB, as well as clues for understanding the differences in subcellular distribution of E2F1 and E2F7 during their nucleocytoplasmic shuttling.

NSP9 of SARS-CoV-2 attenuates nuclear transport by hampering nucleoporin 62 dynamics and functions in host cells

Nuclear pore complexes (NPC) regulate molecular traffics on nuclear envelope, which plays crucial roles during cell fate specification and diseases. The viral accessory protein NSP9 of SARS-CoV-2 is reported to interact with nucleoporin 62 (NUP62), a structural component of the NPC, but its biological impact on the host cell remain obscure. Here, we established new cell line models with ectopic NSP9 expression and determined the subcellular destination and biological functions of NSP9. Confocal imaging identified NSP9 to be largely localized in close proximity to the endoplasmic reticulum. In agreement with the subcellular distribution of NSP9, association of NSP9 with NUP62 was observed in cytoplasm. Furthermore, the overexpression of NSP9 correlated with a reduction of NUP62 expression on the nuclear envelope, suggesting that attenuating NUP62 expression might have contributed to defective NPC formation. Importantly, the loss of NUP62 impaired translocation of p65, a subunit of NF-κB, upon TNF-α stimulation. Concordantly, NSP9 over-expression blocked p65 nuclear transport. Taken together, these data shed light on the molecular mechanisms underlying the modulation of host cells during SARS-CoV-2 infection.

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.

Splicing Factor DDX23, Transcriptionally Activated by E2F1, Promotes Ovarian Cancer Progression by Regulating FOXM1

Ovarian carcinoma remains the most lethal gynecological carcinoma. Abnormal expression of splicing factors is closely related to the occurrence and development of tumors. The DEAD-box RNA helicases are important members of the splicing factor family. However, their role in the occurrence and progression of ovarian cancer is still unclear. In this study, we identified DEAD-box helicase 23 (DDX23) as a key DEAD-box RNA helicase in ovarian cancer using bioinformatics methods. We determined that DDX23 was upregulated in ovarian cancer and its high expression predicted poor prognosis. Functional assays indicated that DDX23 silencing significantly impeded cell proliferation/invasion in vitro and tumor growth in vivo. Mechanistically, transcriptomic analysis showed that DDX23 was involved in mRNA processing in ovarian cancer cells. Specifically, DDX23 regulated the mRNA processing of FOXM1. DDX23 silencing reduced the production of FOXM1C, the major oncogenic transcript of FOXM1 in ovarian cancer, thereby decreasing the FOXM1 protein expression and attenuating the malignant progression of ovarian cancer. Rescue assays indicated that FOXM1 was a key executor in DDX23-induced malignant phenotype of ovarian cancer. Furthermore, we confirmed that DDX23 was transcriptionally activated by the transcription factor (TF) E2F1 in ovarian cancer using luciferase reporter assays and chromatin immunoprecipitation (ChIP) assays. In conclusion, our study demonstrates that high DDX23 expression is involved in malignant behavior of ovarian cancer and DDX23 may become a potential target for precision therapy of ovarian cancer.

Multiomics-based analyses of KPNA2 highlight its multiple potentials in hepatocellular carcinoma

Dysregulation and prognostic roles of Karyopherin α2 (KPNA2) were reported in many malignancies including hepatocellular carcinoma (HCC). A multi-omics analysis of KPNA2 is needed to gain a deeper understanding of its multilevel molecular characteristics and provide novel clues for HCC diagnosis, prognosis, and target therapy. Herein multi-omic alterations of KPNA2 were analyzed at genetic, epigenetic, transcript, and protein levels with evaluation of their relevance with clinicopathological features of HCC by integrative analyses. The significant correlations of KPNA2 expression with its gene copy number variation (CNV) and methylation status were shown through Spearman correlation analyses. With Cox regression, Kaplan-Meier survival, and receiver operating characteristic (ROC) analyses, based on the factors of KPNA2 CNV, methylation, expression, and tumor stage, risk models for HCC overall survival (OS) and disease-free survival (DFS) were constructed which could discriminate the 1-year, 3-year, and 5-year OS/DFS status effectively. With Microenvironment Cell Populations-counter (MCP-counter), the immune infiltrations of HCC samples were evaluated and their associations with KPNA2 were shown. KPNA2 expression in liver was found to be influenced by low fat diet and presented significant correlations with fatty acid metabolism and fatty acid synthase activity in HCC. KPNA2 was detected lowered in HCC patient's plasma by enzyme linked immunosorbent assay (ELISA), consistent with its translocation to nuclei of HCC cells. In conclusion, KPNA2 multilevel dysregulation in HCC and its correlations with immune infiltration and the fatty acid metabolism pathway indicated its multiple roles in HCC. The clinicopathological significance of KPNA2 was highlighted through the in-depth analyses at multilevels.

E2F transcription factor 1 (E2F1) promotes the transforming growth factor TGF-β1 induced human cardiac fibroblasts differentiation through promoting the transcription of CCNE2 gene

The differentiation of cardiac fibroblast to myofibroblast is the key process of cardiac fibrosis. In the study, we aimed to determine the function of E2F Transcription Factor 1 (E2F1) in human cardiac fibroblasts (HCFs) differentiation, search for its downstream genes and elucidate the function of them in HCFs differentiation. As a result, we found that E2F1 was up-regulated in TGF-β1-induced HCFs differentiation. Silencing the expression of E2F1 by siRNA in HCFs, we found that the expression of differentiation-related genes (Collagen-1, α-Smooth muscle actin, and Fibronectin-1) was significantly suppressed, combining with proliferation and migration assay, we determined that HCFs differentiation was decreased. Luciferase report assay and immunoprecipitation proved that the oncogene CCNE2 was a direct target gene of E2F1, overexpression of CCNE2 was found in differentiated HCFs, silencing the expression of CCNE2 by siRNA decreased HCFs differentiation. Our research suggested that E2F1 and its downstream target gene CCNE2 play a vital role in TGF-β1-induced HCFs differentiation, thus E2F1 and CCNE2 may be a potential therapeutic target for cardiac fibrosis.

Methyl Ferulic Acid Attenuates Human Cardiac Fibroblasts Differentiation and Myocardial Fibrosis by Suppressing pRB-E2F1/CCNE2 and RhoA/ROCK2 Pathway

Background: Myocardial fibrosis is a key pathological process after myocardial infarction, which leads to poor outcomes in patients at the end stage. Effective treatments for improving prognosis of myocardial fibrosis are needed to be further developed. Methyl ferulic acid (MFA), a biologically active monomer extracted and purified from the Chinese herbal medicine, is reported as an attenuator in many diseases. In this study, we aim to reveal the role it plays in myocardial fibrosis after myocardial infarction and its possible mechanism. Results: Firstly, we found that MFA attenuated the expression of fibrosis-related proteins and the ability of migration and proliferation in TGF-β1-induced human cardiac fibroblasts (HCFs). Then, myocardial fibrosis after myocardial infarction models on mouse was built to reveal the in vivo affection of MFA. After 28 days of treatments, fibrosis areas, cardiac function, and expression of fibrosis-related proteins were all improved in the MFA-treated group than the myocardial infarction group. Finally, to elucidate the mechanism of phenomenon we observed, we found that MFA attenuated HCF differentiation after myocardial infarction by suppressing the migration and proliferation in HCFs, which was by suppressing the pRB-E2F1/CCNE2 and the RhoA/ROCK2 pathway. Conclusion: Our findings showed that MFA attenuated the expression of fibrosis-related proteins, and the ability of migration and proliferation in HCFs improved the cardiac function of myocardial infarction mice; meanwhile, the mechanism of that was by suppressing the pRB-E2F1/CCNE2 and the RhoA/ROCK2 pathway.

Rac GTPase activating protein 1 promotes gallbladder cancer via binding DNA ligase 3 to reduce apoptosis

Rac GTPase activating protein 1 (RACGAP1) has been characterized in the pathogenesis and progression of several malignancies, however, little is known regarding its role in the development of gallbladder cancer (GBC). This investigation seeks to describe the role of RACGAP1 and its associated molecular mechanisms in GBC. It was found that RACGAP1 was highly expressed in human GBC tissues, which was associated to poorer overall survival (OS). Gene knockdown of RACGAP1 hindered tumor cell proliferation and survival both in vitro and in vivo. We further identified that RACGAP1 was involved in DNA repair through its binding with DNA ligase 3 (LIG3), a crucial component of the alternative-non-homologous end joining (Alt-NHEJ) pathway. RACGAP1 regulated LIG3 expression independent of RhoA activity. RACGAP1 knockdown resulted in LIG3-dependent repair dysfunction, accumulated DNA damage and Poly(ADP-ribosyl) modification (PARylation) enhancement, leading to increased apoptosis and suppressed cell growth. We conclude that RACGAP1 exerts a tumor-promoting role via binding LIG3 to reduce apoptosis and facilitate cell growth in GBC, pointing to RACGAP1 as a potential therapeutic target for GBC.

Identification of E2F transcription factor 7 as a novel potential biomarker for oral squamous cell carcinoma

BACKGROUND

As a tumor-accelerating transcriptional factor, E2F transcription factor 7 (E2F7) was up-regulated in many forms of cancers. Nevertheless, little has been reported about the impacts of E2F7 on oral squamous cell carcinoma (OSCC). Here, we aimed to probe whether E2F7 had influences on OSCC and its potential mechanism.

METHODS

The expression of E2F7 in OSCC tissues was analyzed using the data acquired from TCGA and ONCOMINE databases. E2F7 prognostic value in OSCC patients was analyzed utilizing TCGA database. The expression of E2F7 in OSCC cell lines was detected by qRT-PCR. Gain-and loss-function of E2F7 assays in TCA-83 and CAL27 cells were performed respectively to inquire the function of E2F7. Western blotting was applied to test the alternations of EMT-related markers.

RESULTS

In OSCC tissues, E2F7 was highly expressed. Besides, high expression of E2F7 predicted worse prognosis in OSCC patients. Moreover, E2F7 was over-expressed in TCA-83, HSC-4 and CAL27 (all OSCC cell lines) cells relative to that in HNOK (a normal cell line) cells. Gain-and loss-function assays displayed that deficiency of E2F7 suppresses CAL27 cell growth, migration, invasion and E2F7 high-expression resulted in inverse outcomes in TCA-83 cells. Finally, we found that silencing of E2F7 facilitated E-cadherin protein expression level and reduced N-cadherin, Vimentin and Snail protein levels in CAL27 cells, whilst E2F7 high-expression exhibited the opposite effects in TCA-83 cells.

CONCLUSIONS

These outcomes indicated that E2F7 performs a carcinogenic role in OSCC, which provides a theoretical basis for the therapeutic strategies of OSCC.

LOXL1 exerts oncogenesis and stimulates angiogenesis through the LOXL1-FBLN5/αvβ3 integrin/FAK-MAPK axis in ICC

Aberrant expression of lysyl oxidase-like 1 (LOXL1) reportedly leads to fibrous diseases. Recent studies have revealed its role in cancers. In this study, we observed an elevated level of LOXL1 in the tissues and sera of patients with intrahepatic cholangiocarcinoma (ICC) compared with levels in nontumor tissues and sera of unaffected individuals. Overexpression of LOXL1 in RBE and 9810 cell lines promoted cell proliferation, colony formation, and metastasis in vivo and in vitro and induced angiogenesis. In contrast, depletion of LOXL1 showed the opposite effects. We further showed that LOXL1 interacted with fibulin 5 (FBLN5), which regulates angiogenesis, through binding to the αvβ3 integrin in an arginine-glycine-aspartic (Arg-Gly-Asp) domain-dependent mechanism and enhanced the focal adhesion kinase (FAK)-mitogen-activated protein kinase (MAPK) signaling pathway inside vascular endothelial cells. Our findings shed light on the molecular mechanism underlying LOXL1 regulation of angiogenesis in ICC development and indicate that the LOXL1-FBLN5/αvβ3 integrin/FAK-MAPK axis might be the critical pathological link leading to angiogenesis in ICC.

E2F7 Transcriptionally Inhibits MicroRNA-199b Expression to Promote USP47, Thereby Enhancing Colon Cancer Tumor Stem Cell Activity and Promoting the Occurrence of Colon Cancer

microRNAs (miRNAs) can modulate the expression level of genes in a post-transcription manner, which are closely related to growth and metastasis of colon cancer. Herein, we aimed to explore how miR-199b influences colon cancer and to characterize its underlying molecular mechanism associating with E2F transcription factor 7 (E2F7). Assays of RT-qPCR, Western blot, and immunohistochemistry were utilized to detect the expression of E2F7 in the tissue samples collected from 30 patients diagnosed with colon cancer. Flow analysis was utilized to detect the ratio of ALDH1⁺ and CD133⁺ colon cancer stem cells. The interaction between E2F7, miR-199b, USP47, and MAPK was identified by ChIP-Seq analysis, luciferase reporter, RNA pull-down, co-immunoprecipitation, as well as glutathione-S-transferase (GST) pull-down experiments. Based on the gain- and loss-of-function approaches, the cellular functions of colon cancer cells by the E2F7-regulated miR-199b/USP47/MAPK axis were assessed. It was identified that E2F7 are expressed highly in the collected colon cancer tissues. E2F7 silencing reduced the production of ALDH1⁺ and CD133⁺ colon cancer stem cells and antagonized the effects of 5-fluorouracil (5-FU) treatment. Besides, the silencing of E2F7 was observed to suppress the oxidative stress, proliferation, migration, as well as invasion of ALDH1⁺ cells in vitro and tumorigenesis of colon cancer cells in vivo. Our findings reveal the pro-oncogenic effect of E2F7 on colon cancer development, highlighting E2F7 as a novel target for therapeutic strategy for colon cancer.

E2F7-EZH2 axis regulates PTEN/AKT/mTOR signalling and glioblastoma progression

BACKGROUND

E2F transcription factors are considered to be important drivers of tumour growth. E2F7 is an atypical E2F factor, and its role in glioblastoma remains undefined.

METHODS

E2F7 expression was examined in patients by IHC and qRT-PCR. The overall survival probability was determined by statistical analyses. MTT assay, colony formation, cell-cycle assay, cell metastasis and the in vivo model were employed to determine the functional role of E2F7 in glioblastoma. Chromatin immunoprecipitation, luciferase assay and western blot were used to explore the underlying mechanisms.

RESULTS

E2F7 was found to be up-regulated in glioblastoma patients, and high E2F7 expression was associated with poor overall survival in glioblastoma patients. Functional studies showed that E2F7 promoted cell proliferation, cell-cycle progression, cell metastasis and tumorigenicity abilities in vitro and in vivo. E2F7 promoted the transcription of EZH2 by binding to its promoter and increased H3K27me3 level. EZH2 recruited H3K27me3 to the promoter of PTEN and inhibited PTEN expression, and then activated the AKT/mTOR signalling pathway. In addition, restored expression of EZH2 recovered the abilities of cell proliferation and metastasis in E2F7-silencing cells.

CONCLUSION

Collectively, our findings indicate that E2F7 promotes cell proliferation, cell metastasis and tumorigenesis via EZH2-mediated PTEN/AKT/mTOR pathway in glioblastoma.

Inhibiting Importin 4-mediated nuclear import of CEBPD enhances chemosensitivity by repression of PRKDC-driven DNA damage repair in cervical cancer

Cervical cancer (CC) remains highest in the mortality of female reproductive system cancers, while cisplatin (CDDP) resistance is the one of main reasons for the lethality. Preceding evidence has supported that karyopherins are associated with chemoresistance. In this study, we simultaneously compared CDDP-incomplete responders with CDDP-complete responders of CC patients and CDDP‐insensitive CC cell lines with CDDP‐sensitive group. We finally identified that DNA-PKcs (PRKDC) was related to CDDP sensitivity after overlapping in CC sample tissues and CC cell lines. Further functional assay revealed that targeting PRKDC by shRNA and NU7026 (specific PRKDC inhibitor) could enhance CDDP sensitivity in vitro and in vivo, which was mediated by impairing DNA damage repair pathway in CC. Mechanistically, we found that PRKDC was transcriptionally upregulated by CCAAT/enhancer-binding protein delta (CEBPD), while intriguingly, CDDP treatment strengthened the transcriptional activity of CEBPD to PRKDC. We further disclosed that Importin 4 (IPO4) augmented the nuclear translocation of CEBPD through nuclear localization signals (NLS) to activate PRKDC-mediated DNA damage repair in response to CDDP. Moreover, we demonstrated that IPO4 and CEBPD knockdown improved CDDP-induced cytotoxicity in vitro and in vivo. Together, we shed the novel insight into the role of IPO4 in chemosensitivity and provide a clinical translational potential to enhance CC chemosensitivity since the IPO4-CEBPD-PRKDC axis is actionable via NU7026 (PRKDC inhibitor) or targeting IPO4 in combination with CDDP.

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.

High glucose may promote the proliferation and metastasis of hepatocellular carcinoma via E2F1/RRBP1 pathway

AIMS

Diabetes is considered as one of the important risks in the progression of Hepatocellular carcinoma(HCC). Ribosome binding protein 1 (RRBP1), a rough endoplasmic reticulum protein, plays an essential role in diabetes and various cancer. E2F transcription factor 1 (E2F1), an upstream transcription factor of RRBP1, shows promoting tumor progression effect in multifarious cancers. In this research, we tried to identify whether regulating E2F1/RRBP1 pathway could inhibit the proliferation and metastasis of HepG2 cells induced by high glucose.

MAIN METHODS

Proteomic, bioinformatics, molecular biology including RT-qPCR and Western blot, cell biology containing Cell Counting Kit-8 (CCK-8), wound healing assay and transwell assay, and biochemistry analyses incorporating Luciferase assay and CHIP assay were used in this study.

KEY FINDINGS

High glucose promoted the proliferation and metastasis of HepG2 cells through up-regulating the expression of RRBP1. Bioinformatics analysis predicted that E2F1 might be the transcription factor of RRBP1. Knocking-down of E2F1 down-regulated mRNA and protein expression levels of RRBP1 in HepG2 cells significantly and suppressed the proliferation, migration and invasion of cells remarkably, Reverse effect was observed in cells that E2F1 was overexpressed. Meanwhile, luciferase and CHIP assay determined that E2F1 could bind to the RRBP1 promoter and promote the transcription of RRBP1. Finally, rescue assay verified the important role of RRBP1/E2F1 axis in the process of HepG2 cells proliferation and metastasis.

SIGNIFICANCE

All of the above provided possibility to improve the efficiency of HCC complicated with diabetes treatment by regulating the E2F1/RRBP1 pathway.

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.

TASP1 Promotes Gallbladder Cancer Cell Proliferation and Metastasis by Up-regulating FAM49B via PI3K/AKT Pathway

The highly conserved protease TASP1 not only takes part in critical site-specific proteolysis, but also plays an important role in numerous liquid and solid malignancies. However, the TASP1 expression and its biological regulation function in malignant gallbladder carcinoma (GBC) remain fully unknown. Here we observed that TASP1 levels were substantially overexpressed in GBC samples compared with non-tumor tissues. High TASP1 level was closely associated with T stage and metastasis, and was also correlated with poor prognosis in GBC patients. The depletion of TASP1 inhibited GBC cell proliferation and metastasis in vitro and in vivo. Furthermore, we first revealed that FAM49B had biological function and was positively regulated by TASP1 activating PI3K/AKT signaling pathway in GBC. At the same time, FAM49B also promoted GBC cell proliferation and migration. Inhibition of PI3K/AKT with LY294002 or FAM49B expression abrogated Myc-TASP1/Lv-shTASP1-induced GBC cell proliferation and motility. In conclusion, these findings demonstrate that TASP1 is critical for GBC progression via TASP1-PI3K/AKT-FAM49B axis and it may be a novel prognostic factor. The therapeutic targeting TASP1 may be a potential treatment approach for GBC patients.

IRF1 Negatively Regulates Oncogenic KPNA2 Expression Under Growth Stimulation and Hypoxia in Lung Cancer Cells

Purpose

Karyopherin alpha 2 (KPNA2) has been reported as an oncogenic protein in numerous human cancers and is currently considered a potential therapeutic target. However, the transcriptional regulation and physiological conditions underlying KPNA2 expression remain unclear. The aim of the present study was to investigate the role and regulation of interferon regulatory factor-1 (IRF1) in modulating KPNA2 expression in lung adenocarcinoma (ADC).

Materials and methods

Bioinformatics tools and chromatin immunoprecipitation were used to analyze the transcription factor (TF) binding sites in the KPNA2 promoter region. We searched for a potential role of IRF1 in non-small-cell lung cancer (NSCLC) using Oncomine and Kaplan-Meier Plotter datasets. qRT-PCR was applied to examine the role of IRF1 and signaling involved in regulating KPNA2 transcription. Western blotting was used to determine the effects of extracellular stimulation and intracellular signaling on the modulation of KPNA2-related TF expression.

Results

IRF1 was identified as a novel TF that suppresses KPNA2 gene expression. We observed that IRF1 expression was lower in cancerous tissues than in normal lung tissues and that its low expression was correlated with poor prognosis in NSCLC. Notably, both ataxia telangiectasia mutated (ATM) and mechanistic target of rapamycin (mTOR) inhibitors reduced KPNA2 expression, which was accompanied by increased expression of IRF1 but decreased expression of E2F1, a TF that promotes KPNA2 expression in lung ADC cells. IRF1 knockdown restored the reduced levels of KPNA2 in ATM inhibitor-treated cells. We further demonstrated that epidermal growth factor (EGF)-activated mTOR and hypoxia-induced ATM suppressed IRF1 expression but promoted E2F1 expression, which in turn upregulated KPNA2 expression in lung ADC cells.

Conclusion

IRF1 acts as a potential tumor suppressor in NSCLC. EGF and hypoxia promote KPNA2 expression by simultaneously suppressing IRF1 expression and enhancing E2F1 expression in lung ADC cells. Our study provides new insights into targeted therapy for lung cancer.

Disease-specific alteration of karyopherin-α subtype establishes feed-forward oncogenic signaling in head and neck squamous cell carcinoma

Nuclear import, mediated in part by karyopherin-α (KPNA)/importin-α subtypes, regulates transcription factor access to the genome and determines cell fate. However, the cancer-specific changes of KPNA subtypes and the relevancy in cancer biology remain largely unknown. Here, we report that KPNA4, encoding karyopherin-α4 (KPNA4), is exclusively amplified and overexpressed in head and neck of squamous cell carcinoma (HNSCC). Depletion of KPNA4 attenuated nuclear localization signal-dependent transport activity and suppressed malignant phenotypes and induced epidermal differentiation. Mechanistically, KPNA4-mediated nuclear transport of Ras-responsive element-binding protein (RREB1), which sustains Ras/ERK pathway signaling through repressing miR-143/145 expression. Notably, MAPK signaling enhanced trafficking activity of KPNA4 via phosphorylation of KPNA4 at Ser60. These data reveal that KPNA4 establishes a feed-forward cascade that potentiates Ras/ERK signaling in HNSCC.

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.

NOP2/Sun RNA methyltransferase 2 promotes tumor progression via its interacting partner RPL6 in gallbladder carcinoma

NOP2/Sun domain family, member 2 (NSUN2) is a nuclear RNA methyl-transferase catalyzing 5-methylcytosine formation. Evidence shows that NSUN2 is correlated with cell unlimited proliferation. However, its functional role in gallbladder carcinoma (GBC), which is the most common biliary tract malignancy and has a poor prognosis, remains to be determined. Here we found that NSUN2 was highly expressed in GBC tissues as well as cell lines. NSUN2 silencing repressed GBC cell proliferation and tumorigenesis both in vitro and in vivo. Conversely, upregulation of NSUN2 enhanced GBC cell growth and colony formation. We further discovered that RPL6 was a closely interacting partner with NSUN2. Silencing RPL6 resulted in insufficient NSUN2 translational level and accumulative NSUN2 transcriptional level. Exogenous expression of NSUN2 partially rescued the effect of RPL6 in gallbladder cancer progression. Taken together, our data provided novel mechanic insights into the function of NSUN2 in GBC, thus pointing to NSUN2 as a potential and effective therapeutic approach to GBC treatment.