Autophosphorylation transforms DNA-PK from protecting to processing DNA ends.

The DNA-dependent protein kinase (DNA-PK) initially protects broken DNA ends but then promotes their processing during non-homologous end joining (NHEJ). Before ligation by NHEJ, DNA hairpin ends generated during V(D)J recombination must be opened by the Artemis nuclease, together with autophosphorylated DNA-PK. Structures of DNA-PK bound to DNA before and after phosphorylation, and in complex with Artemis and a DNA hairpin, reveal an essential functional switch. When bound to open DNA ends in its protection mode, DNA-PK is inhibited for cis-autophosphorylation of the so-called ABCDE cluster but activated for phosphorylation of other targets. In contrast, DNA hairpin ends promote cis-autophosphorylation. Phosphorylation of four Thr residues in ABCDE leads to gross structural rearrangement of DNA-PK, widening the DNA binding groove for Artemis recruitment and hairpin cleavage. Meanwhile, Artemis locks DNA-PK into the kinase-inactive state. Kinase activity and autophosphorylation of DNA-PK are regulated by different DNA ends, feeding forward to coordinate NHEJ events.

Insights into the mechanisms and structure of breakage-fusion-bridge cycles in cervical cancer using long-read sequencing.

Cervical cancer is caused by human papillomavirus (HPV) infection, has few approved targeted therapeutics, and is the most common cause of cancer death in low-resource countries. We characterized 19 cervical and four head and neck cancer cell lines using long-read DNA and RNA sequencing and identified the HPV types, HPV integration sites, chromosomal alterations, and cancer driver mutations. Structural variation analysis revealed telomeric deletions associated with DNA inversions resulting from breakage-fusion-bridge (BFB) cycles. BFB is a common mechanism of chromosomal alterations in cancer, and our study applies long-read sequencing to this important chromosomal rearrangement type. Analysis of the inversion sites revealed staggered ends consistent with exonuclease digestion of the DNA after breakage. Some BFB events are complex, involving inter- or intra-chromosomal insertions or rearrangements. None of the BFB breakpoints had telomere sequences added to resolve the dicentric chromosomes, and only one BFB breakpoint showed chromothripsis. Five cell lines have a chromosomal region 11q BFB event, with YAP1-BIRC3-BIRC2 amplification. Indeed, YAP1 amplification is associated with a 10-year-earlier age of diagnosis of cervical cancer and is three times more common in African American women. This suggests that individuals with cervical cancer and YAP1-BIRC3-BIRC2 amplification, especially those of African ancestry, might benefit from targeted therapy. In summary, we uncovered valuable insights into the mechanisms and consequences of BFB cycles in cervical cancer using long-read sequencing.

System-wide Profiling of RNA-Binding Proteins Uncovers Key Regulators of Virus Infection.

The compendium of RNA-binding proteins (RBPs) has been greatly expanded by the development of RNA-interactome capture (RIC). However, it remained unknown if the complement of RBPs changes in response to environmental perturbations and whether these rearrangements are important. To answer these questions, we developed "comparative RIC" and applied it to cells challenged with an RNA virus called sindbis (SINV). Over 200 RBPs display differential interaction with RNA upon SINV infection. These alterations are mainly driven by the loss of cellular mRNAs and the emergence of viral RNA. RBPs stimulated by the infection redistribute to viral replication factories and regulate the capacity of the virus to infect. For example, ablation of XRN1 causes cells to be refractory to SINV, while GEMIN5 moonlights as a regulator of SINV gene expression. In summary, RNA availability controls RBP localization and function in SINV-infected cells.

The RNase PARN Controls the Levels of Specific miRNAs that Contribute to p53 Regulation.

PARN loss-of-function mutations cause a severe form of the hereditary disease dyskeratosis congenita (DC). PARN deficiency affects the stability of non-coding RNAs such as human telomerase RNA (hTR), but these effects do not explain the severe disease in patients. We demonstrate that PARN deficiency affects the levels of numerous miRNAs in human cells. PARN regulates miRNA levels by stabilizing either mature or precursor miRNAs by removing oligo(A) tails added by the poly(A) polymerase PAPD5, which if remaining recruit the exonuclease DIS3L or DIS3L2 to degrade the miRNA. PARN knockdown destabilizes multiple miRNAs that repress p53 translation, which leads to an increase in p53 accumulation in a Dicer-dependent manner, thus explaining why PARN-defective patients show p53 accumulation. This work also reveals that DIS3L and DIS3L2 are critical 3' to 5' exonucleases that regulate miRNA stability, with the addition and removal of 3' end extensions controlling miRNA levels in the cell.

Integrated mutational landscape analysis of poorly differentiated high-grade neuroendocrine carcinoma of the uterine cervix.

High-grade neuroendocrine cervical cancers (NETc) are exceedingly rare, highly aggressive tumors. We analyzed 64 NETc tumor samples by whole-exome sequencing (WES). Human papillomavirus DNA was detected in 65.6% (42/64) of the tumors. Recurrent mutations were identified in PIK3CA, KMT2D/MLL2, K-RAS, ARID1A, NOTCH2, and RPL10. The top mutated genes included RB1, ARID1A, PTEN, KMT2D/MLL2, and WDFY3, a gene not yet implicated in NETc. Somatic CNV analysis identified two copy number gains (3q27.1 and 19q13.12) and five copy number losses (1p36.21/5q31.3/6p22.2/9q21.11/11p15.5). Also, gene fusions affecting the ACLY-CRHR1 and PVT1-MYC genes were identified in one of the eight samples subjected to RNA sequencing. To resolve evolutionary history, multiregion WES in NETc admixed with adenocarcinoma cells was performed (i.e., mixed-NETc). Phylogenetic analysis of mixed-NETc demonstrated that adenocarcinoma and neuroendocrine elements derive from a common precursor with mutations typical of adenocarcinomas. Over one-third (22/64) of NETc demonstrated a mutator phenotype of C > T at CpG consistent with deficiencies in MBD4, a member of the base excision repair (BER) pathway. Mutations in the PI3K/AMPK pathways were identified in 49/64 samples. We used two patient-derived-xenografts (PDX) (i.e., NET19 and NET21) to evaluate the activity of pan-HER (afatinib), PIK3CA (copanlisib), and ATR (elimusertib) inhibitors, alone and in combination. PDXs harboring alterations in the ERBB2/PI3K/AKT/mTOR/ATR pathway were sensitive to afatinib, copanlisib, and elimusertib (P < 0.001 vs. controls). However, combinations of copanlisib/afatinib and copanlisib/elimusertib were significantly more effective in controlling NETc tumor growth. These findings define the genetic landscape of NETc and suggest that a large subset of these highly lethal malignancies might benefit from existing targeted therapies.

USP1 Is Required for Replication Fork Protection in BRCA1-Deficient Tumors.

BRCA1-deficient tumor cells have defects in homologous-recombination repair and replication fork stability, resulting in PARP inhibitor sensitivity. Here, we demonstrate that a deubiquitinase, USP1, is upregulated in tumors with mutations in BRCA1. Knockdown or inhibition of USP1 resulted in replication fork destabilization and decreased viability of BRCA1-deficient cells, revealing a synthetic lethal relationship. USP1 binds to and is stimulated by fork DNA. A truncated form of USP1, lacking its DNA-binding region, was not stimulated by DNA and failed to localize and protect replication forks. Persistence of monoubiquitinated PCNA at the replication fork was the mechanism of cell death in the absence of USP1. Taken together, USP1 exhibits DNA-mediated activation at the replication fork, protects the fork, and promotes survival in BRCA1-deficient cells. Inhibition of USP1 may be a useful treatment for a subset of PARP-inhibitor-resistant BRCA1-deficient tumors with acquired replication fork stabilization.

Protein Dynamics in Complex DNA Lesions.

A single mutagen can generate multiple different types of DNA lesions. How different repair pathways cooperate in complex DNA lesions, however, remains largely unclear. Here we measured, clustered, and modeled the kinetics of recruitment and dissociation of 70 DNA repair proteins to laser-induced DNA damage sites in HeLa cells. The precise timescale of protein recruitment reveals that error-prone translesion polymerases are considerably delayed compared to error-free polymerases. We show that this is ensured by the delayed recruitment of RAD18 to double-strand break sites. The time benefit of error-free polymerases disappears when PARP inhibition significantly delays PCNA recruitment. Moreover, removal of PCNA from complex DNA damage sites correlates with RPA loading during 5'-DNA end resection. Our systematic study of the dynamics of DNA repair proteins in complex DNA lesions reveals the multifaceted coordination between the repair pathways and provides a kinetics-based resource to study genomic instability and anticancer drug impact.

The Deubiquitinase USP46 Is Essential for Proliferation and Tumor Growth of HPV-Transformed Cancers.

High-risk human papilloma viruses (HPVs) cause cervical, anal, and oropharyngeal cancers, unlike the low-risk HPVs, which cause benign lesions. E6 oncoproteins from the high-risk strains are essential for cell proliferation and transformation in HPV-induced cancers. We report that a cellular deubiquitinase, USP46, is selectively recruited by the E6 of high-risk, but not low-risk, HPV to deubiqutinate and stabilize Cdt2/DTL. Stabilization of Cdt2, a component of the CRL4Cdt2 E3 ubiquitin ligase, limits the level of Set8, an epigenetic writer, and promotes cell proliferation. USP46 is essential for the proliferation of HPV-transformed cells, but not of cells without HPV. Cdt2 is elevated in human cervical cancers and knockdown of USP46 inhibits HPV-transformed tumor growth in xenografts. Recruitment of a cellular deubiquitinase to stabilize key cellular proteins is an important activity of oncogenic E6, and the importance of E6-USP46-Cdt2-Set8 pathway in HPV-induced cancers makes USP46 a target for the therapy of such cancers.

GWAS meta-analyses clarify the genetics of cervical phenotypes and inform risk stratification for cervical cancer.

Genome-wide association studies (GWAS) have successfully identified associations for cervical cancer, but the underlying mechanisms of cervical biology and pathology remain uncharacterised. Our GWAS meta-analyses fill this gap, as we characterise the genetic architecture of cervical phenotypes, including cervical ectropion, cervicitis, cervical dysplasia, as well as up to 9229 cases and 490 304 controls for cervical cancer from diverse ancestries. Leveraging the latest computational methods and gene expression data, we refine the association signals for cervical cancer and propose potential causal variants and genes at each locus. We prioritise PAX8/PAX8-AS1, LINC00339, CDC42, CLPTM1L, HLA-DRB1 and GSDMB as the most likely candidate genes for cervical cancer signals, providing insights into cervical cancer pathogenesis and supporting the involvement of reproductive tract development, immune response and cellular proliferation/apoptosis. We construct a genetic risk score (GRS) that is associated with cervical cancer [hazard ratios (HR) = 3.1 (1.7-5.6) for the top 15% vs lowest 15% of individuals], and with other HPV- and immune-system-related diagnoses in a phenome-wide association study analysis. Our results propose valuable leads for further functional studies and present a GRS for cervical cancer that allows additional risk stratification and could potentially be used to personalise the conventional screening strategies for groups more susceptible to cervical cancer.

Chimera RNA transcribed from integrated HPV18 genome with adjacent host genomic region promotes oncogenic gene expression through condensate formation.

Most cervical cancers are caused by human papillomavirus (HPV) infection. In HeLa cells, the HPV18 viral genome is integrated at chromosome 8q24.21 and activates transcription of the proto-oncogene c-Myc. However, the mechanism of how the integrated HPV genome and its transcribed RNAs exhibit transcription activation function has not been fully elucidated. In this study, we found that HPV18 transcripts contain an enhancer RNA-like function to activate proximal genes including CCAT1-5L and c-Myc. We showed that the human genome-integrated HPV18 genes are activated by transcription coregulators including BRD4 and Mediator. The transcribed HPV18 RNAs form a liquid-like condensate at chromosome 8q24.21 locus, which in turn accumulates RNA polymerase II. Moreover, we focused on a relatively uncharacterized transcript from the upstream region of CCAT1, named URC. The URC RNA is transcribed as a chimera RNA with HPV18 and is composed of the 3'-untranslated region of the HPV18 transcript. We experimentally showed that the URC contributes to stabilization of HPV18 RNAs by supplying a polyadenylation site for the HPV18 transcript. Our findings suggest that integrated HPV18 at 8q24.21 locus produces HPV18-URC chimera RNA and promotes tumorigenesis through RNA-based condensate formation.

METTL3's role in cervical cancer development through m6A modification.

N6-methylated adenosine (m6A) is a crucial RNA modification in eukaryotes, particularly in cancer. However, its role in cervical cancer (CC) is unclear. We aimed to elucidate the part of m6A in CC by analyzing methyltransferase-like 3 (METTL3) expression, identifying downstream targets, and exploring the underlying mechanism. We assessed METTL3 expression in CC using western blotting, quantitative polymerase chain reaction (qPCR), and immunohistochemistry. In vitro and in vivo experiments examined METTL3's role in CC. We employed RNA sequencing, methylated RNA immunoprecipitation sequencing, qPCR, and RNA immunoprecipitation qPCR to explore METTL3's mechanism in CC. METTL3 expression was upregulated in CC, promoting cell proliferation and metastasis. METTL3 knockdown inhibited human cervical cancer by inactivating AKT/mTOR signaling pathway. METTL3-mediated m6A modification was observed in CC cells, targeting phosphodiesterase 3A (PDE3A). METTL3 catalyzed m6A modification on PDE3A mRNA through YTH domain family protein 3 (YTHDF3). Our study indicated the mechanism of m6A modification in CC and suggested the METTL3/YTHDF3/PDE3A axis as a potential clinical target for CC treatment.

KIF23 promotes cervical cancer progression via inhibiting NLRP3-mediated pyroptosis.

BACKGROUND: Cervical cancer (CC), closely linked to persistent human papillomavirus infection, represents a major health problem for women worldwide. The objective of this study is to elucidate KIF23's role in the development of CC and its regulatory mechanism. METHODS: The bioinformatics methods were utilized to extract pyroptosis-associated differentially expressed genes (DEGs) and pivot genes from the GSE9750 and GSE63678 datasets, followed by immune infiltration analysis and quantification of these genes' expression. The effects of kinesin family member 23 (KIF23) were verified through functional experiments in vitro and a mouse xenograft model. The NLPR3 activator, nigericin, was applied for further analyzing the potential regulatory mechanism of KIF23 in CC. RESULTS: A total of 8 pyroptosis-related DEGs were screened out, among which 4 candidate core genes were identified as candidate hub genes and confirmed upregulation in CC tissues and cells. These genes respectively showed a positive correlation with the infiltration of distinct immune cells or tumor purity. Downregulation of KIF23 could suppress the proliferation, migration, and invasion abilities in CC cells and tumorigenesis through enhancing pyroptosis. Conversely, KIF23 overexpression accelerated the malignant phenotypes of CC cells and inhibited pyroptosis activation, which was blocked by nigericin treatment. CONCLUSIONS: KIF23 may play an oncogenic role in CC progression via inhibition of the NLRP3-mediated pyroptosis pathway.

From morphology to methylome: epigenetic studies of Müllerian mesonephric-like adenocarcinoma reveal similarities to cervical mesonephric adenocarcinoma†.

Mesonephric adenocarcinomas (MAs) and mesonephric-like adenocarcinomas (MLAs) are rare, aggressive neoplasms that arise in the gynecologic tract and show overlapping morphologic, immunohistochemical, and molecular features. While MAs occur in the cervix and are thought to arise from mesonephric remnants, MLAs occur in the endometrium and ovary and are believed to originate from transdifferentiation of Müllerian lesions. Both MAs and MLAs show a variety of architectural patterns, exhibit frequent expression of GATA3 by immunohistochemistry, and harbor KRAS mutations. In a recent article published in The Journal of Pathology, Kommoss and colleagues used DNA methylation profiling to extend these similarities and showed that MLAs and MAs cluster together based on their epigenetic signatures and are epigenetically distinct from other Müllerian adenocarcinomas. They also showed that MLAs and MAs harbor a high number of global copy number alterations. This study provides evidence that MLAs more closely resemble MAs than Müllerian carcinomas on an epigenetic level. As a result, the authors argue that MLA should be renamed 'mesonephric-type adenocarcinoma.' Further research is needed to establish the relationship between these two entities, their etiology, and pathogenesis. © 2024 The Pathological Society of Great Britain and Ireland.

Multiomics sequencing and immune microenvironment characteristics define three subtypes of small cell neuroendocrine carcinoma of the cervix.

Small cell cervical carcinoma (SCCC) is the most common neuroendocrine tumor in the female genital tract, with an unfavorable prognosis and lacking an evidence-based therapeutic approach. Until now, the distinct subtypes and immune characteristics of SCCC combined with genome and transcriptome have not been described. We performed genomic (n = 18), HPV integration (n = 18), and transcriptomic sequencing (n = 19) of SCCC samples. We assessed differences in immune characteristics between SCCC and conventional cervical cancer, and other small cell neuroendocrine carcinomas, through bioinformatics analysis and immunohistochemical assays. We stratified SCCC patients through non-negative matrix factorization and described the characteristics of these distinct types. We further validated it using multiplex immunofluorescence (n = 77) and investigated its clinical prognostic effect. We confirmed a high frequency of PIK3CA and TP53 alterations and HPV18 integrations in SCCC. SCCC and other small cell carcinoma had similar expression signatures and immune cell infiltration patterns. Comparing patients with SCCC to those with conventional cervical cancer, the former presented immune excluded or 'desert' infiltration. The number of CD8+ cells in the invasion margin of SCCC patients predicted favorable clinical outcomes. We identified three transcriptome subtypes: an inflamed phenotype with high-level expression of genes related to the MHC-II complex (CD74) and IFN-α/ß (SCCC-I), and two neuroendocrine subtypes with high-level expression of ASCL1 or NEUROD1, respectively. Combined with multiple technologies, we found that the neuroendocrine groups had more TP53 mutations and SCCC-I had more PIK3CA mutations. Multiplex immunofluorescence validated these subtypes and SCCC-I was an independent prognostic factor of overall survival. These results provide insights into SCCC tumor heterogeneity and potential therapies. © 2024 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

Cervical cancer cell-derived Tie1 expression via PI3K/AKT signaling pathway promotes tumor progression.

BACKGROUND: Tie1 orphan receptor has become a focus of research, Tie1 can form a polymer with Tie2, regulate the Ang/Tie2 pathway and play a vital role in pathological angiogenesis and tumor progression, the function of Tie1 has remained uncertain in the progression of cervical cancer (CC). Here, we investigated the functional influences of Tie1 overexpress on CC in vitro and in vivo. METHODS: We used Immunohistochemistry (IHC) analysis to detect the relative expression of Tie1 in CC, and we analyzed its connection with the overall survival (OS) and progression free survival (PFS)of CC patients. To prove the role of Tie1 in cell proliferation and metastatic, Tie1 expression in CC cell lines was upregulated by lentivirus. RESULTS: The high expression of Tie1 in tumor cells of cervical cancer tissues is significantly correlated with FIGO stage, differentiated tumors, tumors with diameters, deep stromal invasion. We found that cell progression was promoted in Tie1-overexpress CC cell lines in vivo and in vitro. Tie1 potentially exerts a commanding influence on the expression of markers associated with epithelial-mesenchymal transition (EMT) and the PI3K/AKT signaling pathway. CONCLUSIONS: Our research indicates that Tie1 is highly connected to CC progression as it may play a role in the EMT process through the PI3K/AKT signaling pathway.

HPV integration generates a cellular super-enhancer which functions as ecDNA to regulate genome-wide transcription.

Human papillomavirus (HPV) integration is a critical step in cervical cancer development; however, the oncogenic mechanism at the genome-wide transcriptional level is still poorly understood. In this study, we employed integrative analysis on multi-omics data of six HPV-positive and three HPV-negative cell lines. Through HPV integration detection, super-enhancer (SE) identification, SE-associated gene expression and extrachromosomal DNA (ecDNA) investigation, we aimed to explore the genome-wide transcriptional influence of HPV integration. We identified seven high-ranking cellular SEs generated by HPV integration in total (the HPV breakpoint-induced cellular SEs, BP-cSEs), leading to intra-chromosomal and inter-chromosomal regulation of chromosomal genes. The pathway analysis revealed that the dysregulated chromosomal genes were correlated to cancer-related pathways. Importantly, we demonstrated that BP-cSEs existed in the HPV-human hybrid ecDNAs, explaining the above transcriptional alterations. Our results suggest that HPV integration generates cellular SEs that function as ecDNA to regulate unconstrained transcription, expanding the tumorigenic mechanism of HPV integration and providing insights for developing new diagnostic and therapeutic strategies.

CD48 suppresses proliferation and migration as an immune-related prognostic signature in the cervical cancer immune microenvironment.

Cervical cancer (CC) is one of the most common malignant tumors in gynecology. Immunotherapy and targeted therapy are two particularly effective treatments. In this study, weighted gene co-expression network analysis and CIBERSORT algorithm that quantifies the composition of immune cells were used to analyze CC expression data based on the GEO database and identify modules related to T cells. Five candidate hub genes were identified by tumor-infiltrating immune cells estimation and Kaplan-Meier survival analysis according to CC data from The Cancer Genome Atlas (TCGA). Chemotherapeutic response, methylation, and gene mutation analyses were implemented so that the five candidate hub genes identified may be the potential biomarkers and therapeutic targets which were related to T cell infiltration. Moreover, the results of RT-qPCR revealed that CD48 was a tumor suppressor gene, which was negatively correlated with CC stages, lymph node metastasis, and differentiation. Furthermore, the functional study verified that the interference of CD48 was able to boost the proliferation and migration ability in vitro and the growth of transplanted tumors in vivo. Overall, we identified molecular targets related to immune infiltration and prognosis, regarded CD48 as a key molecule involved in the progression of CC, thus providing new insights into the development of molecular therapy and immunotherapeutics against CC.

Unfurling the functional association between long intergenic noncoding RNAs (lincRNAs) and HPV16-related cervical cancer pathogenesis through weighted gene co-expression network analysis of differentially expressed lincRNAs and coding genes.

Long intergenic noncoding RNAs (lincRNAs) do not overlap annotated coding genes and are located in intergenic regions, as opposed to antisense and sense-intronic lncRNAs, located in genic regions. LincRNAs influence gene expression profiles and are thereby key to disease pathogenesis. In this study, we assessed the association between lincRNAs and HPV16-positive cervical cancer (CaCx) pathogenesis using weighted gene co-expression network analysis (WGCNA) with coding genes, comparing differentially expressed lincRNA and coding genes (DElincGs and DEcGs, respectively) in HPV16-positive patients with CaCx (n = 44) with those in HPV-negative healthy individuals (n = 34). Our analysis revealed five DElincG modules, co-expressing and correlating with DEcGs. We validated a substantial number of such module-specific correlations in the HPV16-positive cancer TCGA-CESC dataset. Four such modules, displayed significant correlations with patient traits, such as HPV16 physical status, lymph node involvement and overall survival (OS), highlighting a collaborative effect of all genes within specific modules on traits. Using the DAVID bioinformatics knowledgebase, we identified the underlying biological processes associated with these modules as cancer development and progression-associated pathways. Next, we identified the top 10 DElincGs with the highest connectivity within each functional module. Focusing on the prognostic module hub genes, downregulated CTD-2619J13.13 expression was associated with poor patient OS. This lincRNA gene interacted with 25 coding genes of its module and was associated with such biological processes as keratinization loss and keratinocyte differentiation, reflecting severe disease phenotypes. This study has translational relevance in fighting various cancers with high mortality rates in underdeveloped countries.

EPAS1, a hypoxia- and ferroptosis-related gene, promotes malignant behaviour of cervical cancer by ceRNA and super-enhancer.

Hypoxia and Ferroptosis are associated with the malignant behaviour of cervical cancer. Endothelial PAS domain-containing protein 1 (EPAS1) contributes to the progression of cervical cancer. EPAS1 plays important roles in hypoxia and ferroptosis. Using the GEO dataset, machine-learning algorithms were used to screen for hypoxia- and ferroptosis-related genes (HFRGs) in cervical cancer. EPAS1 was identified as the hub gene. qPCR and WB were used to investigate the expression of EPAS1 in normal and cervical cancer tissues. The proliferation, invasion and migration of EPAS1 cells in HeLa and SiHa cell lines were detected using CCK8, transwell and wound healing assays, respectively. Apoptosis was detected by flow cytometry. A dual-luciferase assay was used to analyse the MALAT1-miR-182-5P-EPAS1 mRNA axis and core promoter elements of the super-enhancer. EPAS1 was significantly overexpressed in cervical cancer tissues. EPAS1 could increase the proliferation, invasion, migration of HeLa and SiHa cells and reduce the apoptosis of HeLa and SiHa cell. According to the double-luciferase assay, EPAS1 expression was regulated by the MALAT1-Mir-182-5p-EPAS1 mRNA axis. EPAS1 is associated with super-enhancers. Double-luciferase assay showed that the core elements of the super-enhancer were E1 and E3. EPAS1, an HFRG, is significantly overexpressed in cervical cancer. EPAS1 promotes malignant behaviour of cervical cancer cells. EPAS1 expression is regulated by super-enhancers and the MALAT1-miR-182-5P- EPAS1 mRNA axis. EPAS1 may be a target for the diagnosis and treatment of cervical cancer.

FNDC5 inhibits malignant growth of human cervical cancer cells via restraining PI3K/AKT pathway.

Cervical cancer (CxCa) is the fourth most frequent cancer in women. This study aimed to determine the role and underlying mechanism of fibronectin type III domain-containing protein 5 (FNDC5) in inhibiting CxCa growth. Experiments were performed in human CxCa tissues, human CxCa cell lines (HeLa and SiHa), and xenograft mouse model established by subcutaneous injection of SiHa cells in nude mice. Bioinformatics analysis showed that CxCa patients with high FNDC5 levels have a longer overall survival period. FNDC5 expression was increased in human CxCa tissues, HeLa and SiHa cells. FNDC5 overexpression or FNDC5 protein not only inhibited proliferation, but also restrained invasion and migration of HeLa and SiHa cells. The effects of FNDC5 were prevented by inhibiting integrin with cilengitide, activating PI3K with recilisib or activating Akt with SC79. FNDC5 inhibited the phosphorylation of PI3K and Akt, which was attenuated by recilisib. PI3K inhibitor LY294002 showed similar effects to FNDC5 in HeLa and SiHa cells. Intravenous injection of FNDC5 (20 µg/day) for 14 days inhibited the tumor growth, and reduced the proliferation marker Ki67 expression and the Akt phosphorylation in the CxCa xenograft mouse model. These results indicate that FNDC5 inhibits the malignant phenotype of CxCa cells through restraining PI3K/Akt signaling. Upregulation of FNDC5 may play a beneficial role in retarding the tumor growth of CxCa.