WTAP Promotes the Excessive Proliferation of Airway Smooth Muscle Cells in Asthma by Enhancing AXIN1 Levels Through the Recognition of YTHDF2.

Asthma is a common chronic respiratory disease in children, the incidence rate of which has increased in recent years. Wilms tumour 1-associated protein (WTAP) is an N6-methyladenosine (m6A) methyltransferase. The purpose of this study was to explore the specific mechanism of WTAP in asthma progression, and clarify the intricate interplay between m6A modifications, WTAP, AXIN1, and their collective impact on airway smooth muscle cells (ASMCs) proliferation in asthma. Platelet-derived growth factor-BB (PDGF-BB)-treated ASMCs were used to establish an asthma model in vitro. The cell phenotype was tested using CCK-8, transwell, and wound healing assays. The expression of the Wnt signalling pathway was detected by western blotting. In addition, the relationship between WTAP/YTDHF2 and AXIN1 was assessed by a double luciferase reporter assay. Actinomycin D treatment and RT‒qPCR assays were performed to determine the mRNA stability of AXIN1. We found that WTAP was significantly increased in PDGF-BB-treated ASMCs. Knockdown of WTAP inhibited the excessive cell viability and migration of ASMCs induced by PDGF-BB. Furthermore, WTAP knockdown increased AXIN1 levels and inhibited the Wnt signalling pathway. Furthermore, WTAP knockdown decreased the m6A levels and enhanced the mRNA stability of AXIN1. WTAP overexpression showed the opposite effect. In addition, YTHDF2 was demonstrated to be the reader that recognizes the WTAP-mediated m6A modification of AXIN1. YTHDF2 knockdown enhanced the mRNA stability of AXIN1 and reversed the effect of WTAP overexpression on PDGF-BB-treated ASMCs. WTAP knockdown inhibited the excessive cell viability and migration of ASMCs by enhancing the m6A levels of AXIN1, which was further recognized by YTHDF2. The upregulation of AXIN1 mediated by the WTAP/YTHDF2 axis further inhibited the Wnt signalling pathway. Our study provides a new method for the treatment of asthma. This work not only deepens our understanding of the molecular underpinnings of asthma but also identifies potential therapeutic targets for the development of novel treatments aimed at inhibiting ASMC proliferation and alleviating asthma symptoms.

Axin1 regulates tooth root development by inhibiting AKT1-mTORC1 activation and Shh translation in Hertwig's epithelial root sheath.

Hertwig's epithelial root sheath (HERS) interacts with dental apical mesenchyme and guides development of the tooth root, which is integral to the function of the whole tooth. However, the key genes in HERS essential for root development are understudied. Here, we show that Axin1, a scaffold protein that negatively regulates canonical Wnt signaling, is strongly expressed in the HERS. Axin1 ablation in the HERS of mice leads to defective root development, but in a manner independent of canonical Wnt signaling. Further studies reveal that Axin1 in the HERS negatively regulates the AKT1-mTORC1 pathway through binding to AKT1, leading to inhibition of ribosomal biogenesis and mRNA translation. Sonic hedgehog (Shh) protein, a morphogen essential for root development, is over-synthesized by upregulated mTORC1 activity upon Axin1 inactivation. Importantly, either haploinsufficiency of the mTORC1 subunit Rptor or pharmacological inhibition of Shh signaling can rescue the root defects in Axin1 mutant mice. Collectively, our data suggest that, independently of canonical Wnt signaling, Axin1 controls ribosomal biogenesis and selective mRNA translation programs via AKT1-mTORC1 signaling during tooth root development.

Axin1 and Axin2 regulate the WNT-signaling landscape to promote distinct mesoderm programs.

How distinct mesodermal lineages - extraembryonic, lateral, intermediate, paraxial and axial - are specified from pluripotent epiblast during gastrulation is a longstanding open question. By investigating AXIN, a negative regulator of the WNT/ß-catenin pathway, we have uncovered new roles for WNT signaling in the determination of mesodermal fates. We undertook complementary approaches to dissect the role of WNT signaling that augmented a detailed analysis of Axin1;Axin2 mutant mouse embryos, including single-cell and single-embryo transcriptomics, with in vitro pluripotent Epiblast-Like Cell differentiation assays. This strategy allowed us to reveal two layers of regulation. First, WNT initiates differentiation of primitive streak cells into mesoderm progenitors, and thereafter, WNT amplifies and cooperates with BMP/pSMAD1/5/9 or NODAL/pSMAD2/3 to propel differentiating mesoderm progenitors into either posterior streak derivatives or anterior streak derivatives, respectively. We propose that Axin1 and Axin2 prevent aberrant differentiation of pluripotent epiblast cells into mesoderm by spatially and temporally regulating WNT signaling levels.

TRIM59 is required for mouse GC-1 cell maintenance through modulating the ubiquitination of AXIN1.

Tripartite motif-containing protein 59 (TRIM59) is a biomarker for multiple tumors with crucial roles. However, the specific role of TRIM59 in germ cells remains largely unknown. Here, we investigated the effects and underlying regulatory mechanisms of TRIM59 on germ cells using the mouse spermatogonial cell line GC-1. Our results demonstrated that TRIM59 promoted proliferation and inhibited apoptosis of GC-1 cells. Mechanistically, TRIM59 maintained GC-1 cell behaviors through ubiquitination of AXIN1 to activate ß-catenin signaling. Furthermore, activation of ß-catenin signaling reversed the effects mediated by Trim59 knockdown in GC-1 cells. Collectively, our study revealed a major role and regulatory mechanism of TRIM59 in GC-1 cells, which sheds new light on the molecular pathogenesis of defects in spermatogenesis and may provide therapeutic targets for treatment of male infertility.

Metformin promotes anti-tumor immunity in STK11 mutant NSCLC through AXIN1-dependent upregulation of multiple nucleotide metabolites.

Background: Metformin has pleiotropic effects beyond glucose reduction, including tumor inhibition and immune regulation. It enhanced the anti-tumor effects of programmed cell death protein 1 (PD-1) inhibitors in serine/threonine kinase 11 (STK11) mutant non-small cell lung cancer (NSCLC) through an axis inhibition protein 1 (AXIN1)-dependent manner. However, the alterations of tumor metabolism and metabolites upon metformin administration remain unclear. Methods: We performed untargeted metabolomics using liquid chromatography (LC)-mass spectrometry (MS)/MS system and conducted cell experiments to verify the results of bioinformatics analysis. Results: According to the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database, most metabolites were annotated into metabolism, including nucleotide metabolism. Next, the differentially expressed metabolites in H460 (refers to H460 cells), H460_met (refers to metformin-treated H460 cells), and H460_KO_met (refers to metformin-treated Axin1 -/- H460 cells) were distributed into six clusters based on expression patterns. The clusters with a reversed expression pattern upon metformin treatment were selected for further analysis. We screened out metabolic pathways through KEGG pathway enrichment analysis and found that multiple nucleotide metabolites enriched in this pathway were upregulated. Furthermore, these metabolites enhanced the cytotoxicity of activated T cells on H460 cells in vitro and can activate the stimulator of the interferon genes (STING) pathway independently of AXIN1. Conclusion: Relying on AXIN1, metformin upregulated multiple nucleotide metabolites which promoted STING signaling and the killing of activated T cells in STK11 mutant NSCLC, indicating a potential immunotherapeutic strategy for STK11 mutant NSCLC.

Dissecting the mediating role of inflammatory factors in the interaction between metabolites and sepsis: insights from bidirectional Mendelian randomization.

Sepsis, a life-threatening condition, involves complex interactions among metabolic alterations, inflammatory mediators, and host responses. This study utilized a bidirectional Mendelian randomization approach to investigate the causal relationships between 1400 metabolites and sepsis, and the mediating role of inflammatory factors. We identified 36 metabolites significantly associated with sepsis (p < 0.05), with AXIN1, FGF-19, FGF-23, IL-4, and OSM showing an inverse association, suggesting a protective role, while IL-2 exhibited a positive correlation, indicating a potential risk factor. Among these metabolites, Piperine and 9-Hydroxystearate demonstrated particularly interesting protective effects against sepsis. Piperine's protective effect was mediated through its interaction with AXIN1, contributing to a 16.296% reduction in sepsis risk. This suggests a potential pathway where Piperine influences sepsis outcomes by modulating AXIN1 levels. 9-Hydroxystearate also exhibited a protective role against sepsis, mediated through its positive association with FGF-19 and negative association with IL-2, contributing 9.436% and 12.565%, respectively, to its protective effect. Experimental validation confirmed significantly elevated IL-2 levels and reduced FGF-19, AXIN1, piperine, and 9-hydroxyoctadecanoic acid levels in sepsis patients compared to healthy controls. Piperine levels positively correlated with AXIN1, while 9-hydroxyoctadecanoic acid levels negatively correlated with IL-2 and positively correlated with FGF-19, supporting the Mendelian randomization findings. Our findings provide insights into the molecular mechanisms of sepsis, highlighting the unique roles and contributions of specific metabolites and their interactions with inflammatory mediators. This study enhances our understanding of sepsis pathophysiology and opens avenues for targeted therapeutic interventions and biomarker development for sepsis management. However, further research is essential to validate these pathways across diverse populations and fully explore the roles of these metabolites in sepsis.

AXIN2 promotes degradation of AXIN1 through tankyrase in colorectal cancer cells.

AXIN1 and AXIN2 are homologous proteins that inhibit the Wnt/ß-catenin signaling pathway, which is frequently hyperactive in colorectal cancer. Stabilization of AXIN1 and AXIN2 by inhibiting their degradation through tankyrase (TNKS) allows the attenuation of Wnt signaling in cancer, attracting interest for potential targeted therapy. Here, we found that knockout or knockdown of AXIN2 in colorectal cancer cells increased the protein stability of AXIN1. The increase in AXIN1 overcompensated for the loss of AXIN2 with respect to protein levels; however, functionally it did not because loss of AXIN2 activated the pathway. Moreover, AXIN2 was highly essential in the context of TNKS inhibition because TNKS-targeting small-molecule inhibitors completely failed to inhibit Wnt signaling and to stabilize AXIN1 in AXIN2 knockout cells. The increased AXIN1 protein stability and the impaired stabilization by TNKS inhibitors indicated disrupted TNKS-AXIN1 regulation in AXIN2 knockout cells. Concordantly, mechanistic studies revealed that co-expression of AXIN2 recruited TNKS to AXIN1 and stimulated TNKS-mediated degradation of transiently expressed AXIN1 wild-type and AXIN1 mutants with impaired TNKS binding. Taken together, our data suggest that AXIN2 promotes degradation of AXIN1 through TNKS in colorectal cancer cells by directly linking the two proteins, and these findings may be relevant for TNKS inhibition-based colorectal cancer therapies.

Hypoxia exposure induces lactylation of Axin1 protein to promote glycolysis of esophageal carcinoma cells.

The hypoxic microenvironment in esophageal carcinoma is an important factor promoting the rapid progression of malignant tumor. This study was to investigate the lactylation of Axin1 on glycolysis in esophageal carcinoma cells under hypoxia exposure. Hypoxia treatment increases pan lysine lactylation (pan-kla) levels of both TE1 and EC109 cells. Meanwhile, ECAR, glucose consumption and lactate production were also upregulated in both TE1 and EC109 cells. The expression of embryonic stem cell transcription factors NANOG and SOX2 were enhanced in the hypoxia-treated cells. Axin1 overexpression partly reverses the induction effects of hypoxia treatment in TE1 and EC109 cells. Moreover, lactylation of Axin1 protein at K147 induced by hypoxia treatment promotes ubiquitination modification of Axin1 protein to promote glycolysis and cell stemness of TE1 and EC109 cells. Mutant Axin1 can inhibit ECAR, glucose uptake, lactate secretion, and cell stemness in TE1 and EC109 cells under normal or hypoxia conditions. Meanwhile, mutant Axin1 further enhanced the effects of 2-DG on inhibiting glycolysis and cell stemness. Overexpression of Axin1 also inhibited tumor growth in vivo, and was related to suppressing glycolysis. In conclusion, hypoxia treatment promoted the glycolysis and cell stemness of esophageal carcinoma cells, and increased the lactylation of Axin1 protein. Overexpression of Axin1 functioned as a glycolysis inhibitor, and suppressed the effects of hypoxia exposure in vitro and inhibited tumor growth in vivo. Mechanically, hypoxia induces the lactylation of Axin1 protein and promotes the ubiquitination of Axin1 to degrade the protein, thereby exercising its anti-glycolytic function.

Intestinal Epithelial Axin1 Deficiency Protects Against Colitis via Altered Gut Microbiota.

Intestinal homeostasis is maintained by specialized host cells and the gut microbiota. Wnt/ß-catenin signaling is essential for gastrointestinal development and homeostasis, and its dysregulation has been implicated in inflammation and colorectal cancer. Axin1 negatively regulates activated Wnt/ß-catenin signaling, but little is known regarding its role in regulating host-microbial interactions in health and disease. Here, we aim to demonstrate that intestinal Axin1 determines gut homeostasis and host response to inflammation. Axin1 expression was analyzed in human inflammatory bowel disease datasets. To explore the effects and mechanism of intestinal Axin1 in regulating intestinal homeostasis and colitis, we generated new mouse models with Axin1 conditional knockout in intestinal epithelial cell (IEC; Axin1 ΔIEC) and Paneth cell (PC; Axin1 ΔPC) to compare with control (Axin1 LoxP; LoxP: locus of X-over, P1) mice. We found increased Axin1 expression in the colonic epithelium of human inflammatory bowel disease (IBD). Axin1 ΔIEC mice exhibited altered goblet cell spatial distribution, PC morphology, reduced lysozyme expression, and enriched Akkermansia muciniphila (A. muciniphila). The absence of intestinal epithelial and PC Axin1 decreased susceptibility to dextran sulfate sodium (DSS)-induced colitis in vivo. Axin1 ΔIEC and Axin1 ΔPC mice became more susceptible to DSS-colitis after cohousing with control mice. Treatment with A. muciniphila reduced DSS-colitis severity. Antibiotic treatment did not change the IEC proliferation in the Axin1 Loxp mice. However, the intestinal proliferative cells in Axin1 ΔIEC mice with antibiotic treatment were reduced compared with those in Axin1 ΔIEC mice without treatment. These data suggest non-colitogenic effects driven by the gut microbiome. In conclusion, we found that the loss of intestinal Axin1 protects against colitis, likely driven by epithelial Axin1 and Axin1-associated A. muciniphila. Our study demonstrates a novel role of Axin1 in mediating intestinal homeostasis and the microbiota. Further mechanistic studies using specific Axin1 mutations elucidating how Axin1 modulates the microbiome and host inflammatory response will provide new therapeutic strategies for human IBD.

AXIN1 mutations in nonsyndromic craniosynostosis.

OBJECTIVE: Occurring once in every 2000 live births, craniosynostosis (CS) is the most frequent cranial birth defect. Although the genetic etiologies of syndromic CS cases are well defined, the genetic cause of most nonsyndromic cases remains unknown. METHODS: The authors analyzed exome or RNA sequencing data from 876 children with nonsyndromic CS, including 291 case-parent trios and 585 additional probands. The authors also utilized the GeneMatcher platform and the Gabriella Miller Kids First genome sequencing project to identify additional CS patients with AXIN1 mutations. RESULTS: The authors describe 11 patients with nonsyndromic CS harboring rare, damaging mutations in AXIN1, an inhibitor of Wnt signaling. AXIN1 regulates signaling upstream of key mediators of osteoblast differentiation. Three of the 6 mutations identified in trios occurred de novo in the proband, while 3 were transmitted from unaffected parents. Patients with nonsyndromic CS were highly enriched for mutations in AXIN1 compared to both expectation (p = 0.0008) and exome sequencing data from > 76,000 healthy controls (p = 2.3 × 10-6), surpassing the thresholds for genome-wide significance. CONCLUSIONS: These findings describe the first phenotype associated with mutations in AXIN1, with mutations identified in approximately 1% of nonsyndromic CS cases. The results strengthen the existing link between Wnt signaling and maintenance of cranial suture patency and have implications for genetic testing in families with CS.

Investigating AXIN1 gene polymorphisms in Turkish children with cryptorchidism: A pilot study.

INTRODUCTION: Cryptorchidism is one of the most common congenital anomalies in male children, occurring in 2-5% of full-term male infants. Both genetic and environmental factors are observed to play a role in its etiology. A study conducted in Japan identified the AXIN1 gene as being associated with cryptorchidism. OBJECTIVE: We aimed to conduct a pilot study on AXIN1 gene polymorphism in Turkish children with cryptorchidism, and whether AXIN1 gene polymorphism is a risk factor for cryptorchidism. STUDY DESIGN: Between January 2023 and December 2023, we have planned a prospective controlled study including 84 boys operated for cryptorchidism as study group, and 96 boys operated for circumcision as control group. The remaining blood samples of preoperative laboratory tests in ethylenediamine tetraacetic acid (EDTA) tubes were kept at -20 Co freezer for genomic studies. Patient demographics, physical examination and operative findings were recorded, study patients were grouped according to testis localization. After collecting all samples, genomic DNA isolation procedure was done, and analysis of the 3 polymorphisms (rs12921862, rs1805105 and rs370681) of AXIN1 gene was performed using conventional Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) method. Genotype and allele frequencies of each group was analyzed and compared. RESULTS: The most common location of cryptorchid testis was proximal inguinal (53%), followed by distal inguinal (25.3%), bilateral (13.3%), and intra-abdominal (8.4%). Regarding the 3 polymorphisms of AXIN1 gene, there was no significant difference between study and control groups, in terms of genotype and allele frequencies (P > 0.05). Eight haplotype blocks were estimated for 3 polymorphisms of AXIN1. However, no significant difference was observed between study and control groups regarding haplotype distributions (P > 0.05). In addition, the comparison of the localization of testis with AXIN1 gene polymorphism did not show any significant difference among cryptorchid testis groups (P > 0.05). DISCUSSION: The AXIN1 gene is located on chromosome 16p and its polymorphisms have been associated with various diseases. In a Chinese study, the rs370681 polymorphism was found to be associated with cryptorchidism. However, our results showed no association between the AXIN1 gene haplotypes for the studied polymorphisms and cryptorchidism. CONCLUSION: In this study we have investigated the AXIN1 gene polymorphism in Turkish children with cryptorchidism as a pilot study. Although we could not identify any difference as compared to control group, further research is necessary to uncover the underlying molecular mechanisms contributing to the development of cryptorchidism.

UBE2N promotes cell viability and glycolysis by promoting Axin1 ubiquitination in prostate cancer cells.

BACKGROUND: Ubiquitin-conjugating enzyme E2 N (UBE2N) is recognized in the progression of some cancers; however, little research has been conducted to describe its role in prostate cancer. The purpose of this paper is to explore the function and mechanism of UBE2N in prostate cancer cells. METHODS: UBE2N expression was detected in Cancer Genome Atlas Prostate Adenocarcinoma (TCGA-PRAD) data, prostate cancer tissue microarrays, and prostate cancer cell lines, respectively. UBE2N knockdown or overexpression was used to analyze its role in cell viability and glycolysis of prostate cancer cells and tumor growth. XAV939 or Axin1 overexpression was co-treated with UBE2N overexpression to detect the involvement of the Wnt/ß-catenin signaling and Axin1 in the UBE2N function. UBE2N interacting with Axin1 was analyzed by co-immunoprecipitation assay. RESULTS: UBE2N was upregulated in prostate cancer and the UBE2N-high expression correlated with the poor prognosis of prostate cancer. UBE2N knockdown inhibited cell viability and glycolysis in prostate cancer cells and restricted tumor formation in tumor-bearing mice. Wnt/ß-catenin inhibition and Axin1 overexpression reversed the promoting viability and glycolysis function of UBE2N. UBE2N promoted Axin1 ubiquitination and decreased Axin1 protein level.

The truncated AXIN1 isoform promotes hepatocellular carcinoma metastasis through SRSF9-mediated exon 9 skipping.

Axis inhibitor protein 1 (AXIN1) is a protein recognized for inhibiting tumor growth and is commonly involved in cancer development. In this study, we explored the potential molecular mechanisms that connect alternative splicing of AXIN1 to the metastasis of hepatocellular carcinoma (HCC). Transcriptome sequencing, RT‒PCR, qPCR and Western blotting were utilized to determine the expression levels of AXIN1 in human HCC tissues and HCC cells. The effects of the AXIN1 exon 9 alternative splice isoform and SRSF9 on the migration and invasion of HCC cells were assessed through wound healing and Transwell assays, respectively. The interaction between SRSF9 and AXIN1 was investigated using UV crosslink RNA immunoprecipitation, RNA pulldown, and RNA immunoprecipitation assays. Furthermore, the involvement of the AXIN1 isoform and SRSF9 in HCC metastasis was validated in a nude mouse model. AXIN1-L (exon 9 including) expression was downregulated, while AXIN1-S (exon 9 skipping) was upregulated in HCC. SRSF9 promotes the production of AXIN1-S by interacting with the sequence of exons 8 and 10 of AXIN1. AXIN1-S significantly promoted HCC cells migration and invasion by activating the Wnt pathway, while the opposite effects were observed for AXIN1-L. In vivo experiments demonstrated that AXIN1-L inhibited HCC metastasis, whereas SRSF9 promoted HCC metastasis in part by regulating the level of AXIN1-S. AXIN1, a tumor suppressor protein that targets the AXIN1/Wnt/ß-catenin signaling axis, may be a promising prognostic factor and a valuable therapeutic target for HCC.

Identification of Germline FOXE1 and Somatic MAPK Pathway Gene Alterations in Patients with Malignant Struma Ovarii, Cleft Palate and Thyroid Cancer.

Germline variants in the FOXE1 transcription factor have been associated with thyroid ectopy, cleft palate (CP) and thyroid cancer (TC). Here, we aimed to clarify the role of FOXE1 in Portuguese families (F1 and F2) with members diagnosed with malignant struma ovarii (MSO), an ovarian teratoma with ectopic malignant thyroid tissue, papillary TC (PTC) and CP. Two rare germline heterozygous variants in the FOXE1 promoter were identified: F1) c.-522G>C, in the proband (MSO) and her mother (asymptomatic); F2) c.9C>T, in the proband (PTC), her sister and her mother (CP). Functional studies using rat normal thyroid (PCCL3) and human PTC (TPC-1) cells revealed that c.9C>T decreased FOXE1 promoter transcriptional activity in both cell models, while c.-522G>C led to opposing activities in the two models, when compared to the wild type. Immunohistochemistry and RT-qPCR analyses of patients' thyroid tumours revealed lower FOXE1 expression compared to adjacent normal and hyperplastic thyroid tissues. The patient with MSO also harboured a novel germline AXIN1 variant, presenting a loss of heterozygosity in its benign and malignant teratoma tissues and observable ß-catenin cytoplasmic accumulation. The sequencing of the F1 (MSO) and F2 (PTC) probands' tumours unveiled somatic BRAF and HRAS variants, respectively. Germline FOXE1 and AXIN1 variants might have a role in thyroid ectopy and cleft palate, which, together with MAPK pathway activation, may contribute to tumours' malignant transformation.

TRAF2 decrease promotes the TGF-ß-mTORC1 signal in MAFLD-HCC through enhancing AXIN1-mediated Smad7 degradation.

According to recent research, metabolic-associated fatty liver disease (MAFLD) has emerged as an important underlying etiology of hepatocellular carcinoma (HCC). However, the molecular mechanism of MAFLD-HCC is still unclear. Tumor necrosis factor receptor-associated factor 2 (TRAF2) is the key molecule to mediate the signal of inflammatory NF-κB pathway. This study aims to investigate the potential dysregulation of TRAF2 and its biological function in MAFLD-HCC. Huh7 TRAF2-/- demonstrated increased tumor formation ability compared to huh7 TRAF2+/+ when stimulated with transforming growth factor-ß (TGF-ß). The decisive role of TGF-ß in the development of MAFLD-HCC was confirmed through the specific depletion of TGF-ß receptor II gene in the hepatocytes (Tgfbr2ΔHep) of mice. In TRAF2-/- cells treated with TGF-ß, both the glycolysis rate and lipid synthesis were enhanced. We proved the signal of the mechanistic target of rapamycin complex 1 (mTORC1) could be activated in the presence of TGF-ß, and was enhanced in TRAF2-/- cells. The coimmunoprecipitation (co-IP) experiments revealed that TRAF2 fortified the Smurf2-mediated ubiquitination degradation of AXIN1. Hence, TRAF2 depletion resulted in increased Smad7 degradation induced by AXIN1, thus promoting the TGF-ß signal. We also discovered that PLX-4720 could bind with AXIN1 and restrained the tumor proliferation of TRAF2-/- in mice fed with high-fat diet (HFD). Our findings indicate that TRAF2 plays a significant role in the pathogenesis of MAFLD-HCC. The reduction of TRAF2 expression leads to the enhancement of the TGF-ß-mTORC1 pathway by facilitating AXIN1-mediated Smad7 degradation.

The CK1ε/SIAH1 axis regulates AXIN1 stability in colorectal cancer cells.

Casein kinase 1ε (CK1ε) and axis inhibitor 1 (AXIN1) are crucial components of the ß-catenin destruction complex in canonical Wnt signaling. CK1ε has been shown to interact with AXIN1, but its physiological function and role in tumorigenesis remain unknown. In this study, we found that CK1δ/ε inhibitors significantly enhanced AXIN1 protein level in colorectal cancer (CRC) cells through targeting CK1ε. Mechanistically, CK1ε promoted AXIN1 degradation by the ubiquitin-proteasome pathway by promoting the interaction of E3 ubiquitin-protein ligase SIAH1 with AXIN1. Genetic or pharmacological inhibition of CK1ε and knockdown of SIAH1 downregulated the expression of Wnt/ß-catenin-dependent genes, suppressed the viability of CRC cells, and restrained tumorigenesis and progression of CRC in vitro and in vivo. In summary, our results demonstrate that CK1ε exerted its oncogenic role in CRC occurrence and progression by regulating the stability of AXIN1. These findings reveal a novel mechanism by which CK1ε regulates the Wnt/ß-catenin signaling pathway and highlight the therapeutic potential of targeting the CK1ε/SIAH1 axis in CRC.

AXIN1/MYC Axis Mediated the Osimertinib Resistance in EGFR Mutant Non-Small Cell Lung Cancer Cells.

Osimertinib, a promising and approved third-generation epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor (TKI), is a standard strategy for EGFR-mutant non-small cell lung cancer (NSCLC) patients. However, developed resistance is unavoidable, which reduces its long-term effectiveness. In this study, RNA sequencing was performed to analyze differentially expressed genes (DEGs). The PrognoScan database and Gene Expression Profiling Interactive Analysis (GEPIA) were used to identify the key genes for clinical prognosis and gene correlation respectively. Protein expression was determined by western blot analysis. Cell viability assay and Ki67 staining were used to evaluate the effect of osimertinib on tumor cells. Finally, we screened out two hub genes, myelocytomatosis oncogene (Myc) and axis inhibition protein 1 (Axin1), upregulated in three osimertinib-resistant cell lines through RNA sequencing and bioinformatics analysis. Next, cell experiment confirmed that expression of C-MYC and AXIN1 were elevated in different EGFR mutant NSCLC cell lines with acquired resistance to osimertinib, compared with their corresponding parental cell lines. Furthermore, we demonstrated that AXIN1 upregulated the expression of C-MYC and mediated the acquired resistance of EGFR mutant NSCLC cells to osimertinib in vitro. In conclusion, AXIN1 affected the sensitivity of EGFR mutant NSCLC to osimertinib via regulating C-MYC expression in vitro. Targeting AXIN1/MYC signaling may be a potential new strategy for overcoming acquired resistance to osimertinib.

The scaffold protein AXIN1: gene ontology, signal network, and physiological function.

AXIN1, has been initially identified as a prominent antagonist within the WNT/ß-catenin signaling pathway, and subsequently unveiled its integral involvement across a diverse spectrum of signaling cascades. These encompass the WNT/ß-catenin, Hippo, TGFß, AMPK, mTOR, MAPK, and antioxidant signaling pathways. The versatile engagement of AXIN1 underscores its pivotal role in the modulation of developmental biological signaling, maintenance of metabolic homeostasis, and coordination of cellular stress responses. The multifaceted functionalities of AXIN1 render it as a compelling candidate for targeted intervention in the realms of degenerative pathologies, systemic metabolic disorders, cancer therapeutics, and anti-aging strategies. This review provides an intricate exploration of the mechanisms governing mammalian AXIN1 gene expression and protein turnover since its initial discovery, while also elucidating its significance in the regulation of signaling pathways, tissue development, and carcinogenesis. Furthermore, we have introduced the innovative concept of the AXIN1-Associated Phosphokinase Complex (AAPC), where the scaffold protein AXIN1 assumes a pivotal role in orchestrating site-specific phosphorylation modifications through interactions with various phosphokinases and their respective substrates.

Axin1's mystique in manipulating microbiome amidst colitis.

Classically, Axin1 is considered a regulator of Wnt/ß-catenin signaling. However, Axin1's roles in host-microbial interactions have been unknown. Our recent study has demonstrated that deletion of intestinal epithelial Axin1 in epithelial cells and Paneth cells protects the host against colitis by enhancing Akkermansia muciniphila. Loss of intestinal epithelial or Paneth cell Axin1 results in increased Wnt/ß-catenin signaling, proliferation, and cell migration. This is associated with morphologically altered goblet and Paneth cells, including increased Muc2 and decreased lysozyme. Axin1 deletion specifically enriched Akkermansia muciniphila. Akkermansia muciniphila in Axin1 knockout mice is the driver of protection against DSS-induced inflammation. Here, we feature several significant conceptual changes, such as differences between Axin1 and Axin2, Axin1 in innate immunity and microbial homeostasis, and Axin1 reduction of Akkermansia muciniphila. We discuss an important trend in the field related to Paneth cells and tissue-specific Axin1 manipulation of microbiome in health and inflammation.

Ischemia-reperfusion injury in human AC16 cardiomyocytes is modulated by AXIN1 depending on c-Myc regulation.

Objective: A major consequence of acute myocardial infarction is myocardial ischemia-reperfusion (I/R) injury. Collecting proof demonstrates that AXIN1 assume a basic part in different disease; however, the role of AXIN1 in I/R injury remains to a great extent obscure. Methods: The I/R injury model on AC16 cells was constructed. siRNA transfection was used to knockdown AXIN1. The qRT-PCR assays and western blot assays were used to detect the expression level of AXIN1 and other key proteins. CCK-8 assays and cell apoptosis assays were used to detect cell proliferation and cell apoptosis. Results: AXIN1 was significantly overexpressed in an in vitro model of I/R injury. Knockdown of AXIN1 significantly restored the cell proliferation inhibition caused by IR injury, while inhibiting apoptosis and inflammation. Further mechanistic studies revealed that the transcription factor c-Myc could regulate the expression of AXIN1. The effects of I/R injury on AC16 cells after overexpression of c-Myc were reversed by knockdown of AXIN1. Meanwhile, AXIN1 could regulate the SIRT1/p53/Nrf 2 pathway. Conclusion: Our results show an important role for AXIN1 and provide new targets for avoiding and treating I/R injury.