Regulator Of Wnt Signaling Pathway Research Articles

The m6A(m)-independent role of FTO in regulating WNT signaling pathways.

FTO and ALKBH5 are the two enzymes responsible for mRNA demethylation. Hence, the functional study of FTO has been focused on its mechanistic role in dynamic mRNA modification, and how this post-transcriptional regulation modulates signaling pathways. Here, we report that the functional landscape of FTO is largely associated with WNT signaling pathways but in a manner that is independent of its enzymatic activity. Re-analyses of public datasets identified the bifurcation of canonical and noncanonical WNT pathways as the major role of FTO. In FTO-depleted cells, we find that the canonical WNT/β-Catenin signaling is attenuated in a non-cell autonomous manner via the up-regulation of DKK1. Simultaneously, this up-regulation of DKK1 promotes cell migration via activating the noncanonical WNT/PCP pathway. Unexpectedly, this regulation of DKK1 is independent of its RNA methylation status but operates at the transcriptional level, revealing a noncanonical function of FTO in gene regulation. In conclusion, this study places the functional context of FTO at the branch point of multiple WNT signaling pathways and extends its mechanistic role in gene regulation.

LncRNA-AK137033 inhibits the osteogenic potential of adipose-derived stem cells in diabetic osteoporosis by regulating Wnt signaling pathway via DNA methylation.

ObjectivesBone tissue engineering based on adipose‐derived stem cells (ASCs) is expected to become a new treatment for diabetic osteoporosis (DOP) patients with bone defects. However, compared with control ASCs (CON‐ASCs), osteogenic potential of DOP‐ASCs is decreased, which increased the difficulty of bone reconstruction in DOP patients. Moreover, the cause of the poor osteogenesis of ASCs in a hyperglycemic microenvironment has not been elucidated. Therefore, this study explored the molecular mechanism of the decline in the osteogenic potential of DOP‐ASCs from the perspective of epigenetics to provide a possible therapeutic target for bone repair in DOP patients with bone defects.Materials and methodsAn animal model of DOP was established in mice. CON‐ASCs and DOP‐ASCs were isolated from CON and DOP mice, respectively. AK137033 small interfering RNA (SiRNA) and an AK137033 overexpression plasmid were used to regulate the expression of AK137033 in CON‐ASCs and DOP‐ASCs in vitro. Lentiviruses that carried shRNA‐AK137033 or AK137033 cDNA were used to knockdown or overexpress AK137033, respectively, in CON‐ASCs and DOP‐ASCs in vivo. Hematoxylin and eosin (H&E), Masson's, alizarin red, and alkaline phosphatase (ALP) staining, micro‐computed tomography (Micro‐CT), flow cytometry, qPCR, western blotting, immunofluorescence, and bisulfite‐specific PCR (BSP) were used to analyze the functional changes of ASCs.ResultsThe DOP mouse model was established successfully. Compared with CON‐ASCs, AK137033 expression, the DNA methylation level of the sFrp2 promoter region, Wnt signaling pathway markers, and the osteogenic differentiation potential were decreased in DOP‐ASCs. In vitro experiments showed that AK137033 silencing inhibited the Wnt signaling pathway and osteogenic ability of CON‐ASCs by reducing the DNA methylation level in the sFrp2 promoter region. Additionally, overexpression of AK137033 in DOP‐ASCs rescued these changes caused by DOP. Moreover, the same results were obtained in vivo.ConclusionsLncRNA‐AK137033 inhibits the osteogenic potential of DOP‐ASCs by regulating the Wnt signaling pathway via modulating the DNA methylation level in the sFrp2 promoter region. This study provides an important reference to find new targets for the treatment of bone defects in DOP patients.

Vitamin D treatment induces in vitro and ex vivo transcriptomic changes indicating anti-tumor effects.

Vitamin D deficiency is associated with risk of several common cancers, including colorectal cancer (CRC). Here we have utilized patient derived epithelial organoids (ex vivo) and CRC cell lines (in vitro) to show that calcitriol (1,25OHD) increased the expression of the CRC tumor suppressor gene, CDH1, at both the transcript and protein level. Whole genome expression analysis demonstrated significant differential expression of a further six genes after 1,25OHD treatment, including genes with established links to carcinogenesis GADD45, EFTUD1 and KIAA1199. Furthermore, gene ontologies relevant to carcinogenesis were enriched by 1,25OHD treatment (e.g., 'regulation of Wnt signaling pathway', 'regulation of cell death'), with common enriched processes across in vitro and ex vivo cultures including 'negative regulation of cell proliferation', 'regulation of cell migration' and 'regulation of cell differentiation'. Our results identify genes and pathways that are modifiable by calcitriol that have links to CRC tumorigenesis. Hence the findings provide potential mechanism to the epidemiological and clinical trial data indicating a causal association between vitamin D and CRC. We suggest there is strong rationale for further well-designed trials of vitamin D supplementation as a novel CRC chemopreventive and chemotherapeutic agent.

MCC Regulator of WNT Signaling Pathway (MCC) Is a Podocyte Essential Gene.

Podocytes are an integral part of the glomerular filtration barrier. Many genes are already known to be essential for podocyte survival, structure and function, but there are more podocyte essential genes to be identified. By single-cell RNA-seq of mouse podocytes, we detected the expression of gene encoding MCC regulator of WNT signaling pathway (MCC) in majority of the podocytes and speculated that MCC is essential for podocytes. We confirmed MCC expression in mouse podocytes and further showed its expression in human podocytes. To experimentally prove the essentiality of MCC for podocytes, we knocked down MCC in cultured podocytes and found marked morphological change of cell shape, cytoskeletal F-actin stress fiber disruption, increased apoptosis, and downregulation of podocyte essential genes, CD2AP and WT1, demonstrating that MCC is essential for podocytes. Since MCC has been implicated in cell cycle and β-catenin signaling, we examined the expression of cell cycle related genes and activity of β-catenin in the MCC knockdown podocytes, but did not find significant changes. To further explore the mechanism underlying the role of MCC in podocytes, we performed RNA-sequencing and bioinformatics analysis of MCC knockdown podocytes and found a significant enrichment of the regulated genes in lamellipodia formation. Consistently, we found that MCC is present in lamellipodia and MCC knockdown resulted in loss of lamellipodia in the cells. Lastly, we found that MCC was downregulated in podocytes treated with puromycin aminonucleosides and in glomeruli of diabetic mice and FSGS patients, implicating MCC is involved in the development of podocytopathy and proteinuria. In conclusion, MCC is potentially essential for podocytes and its downregulation may be involved in podocytopathy.

Hematopoietic stem cell and immunotoxicity in zebrafish embryos induced by exposure to Metalaxyl-M

Metalaxyl-M (MM), a protective and therapeutic fungicide, has been shown to be a promising candidate, but its toxicity toward aquatic organisms is unknown. In this study, we evaluated for the first time the immunotoxicity of MM in zebrafish embryos. Phenotypes (heart rate, body length, and yolk area) and the number of neutrophils, macrophages, and T cells in the thymus were analyzed in zebrafish embryo after exposure to MM. Our results showed that zebrafish embryos exposed to MM showed a concentration-dependent increase in the yolk area and a significant decrease in the number of neutrophils, macrophages, and thymus T cells. We detected upregulated expression of related immune signaling genes, such as tnfa, nfkb3, cxcl-c1c, il6, mmp9, and tgfb1. Additionally, we observed a significant decrease in HSCs in zebrafish larvae after exposure to MM. IWR-1 could restore the number of neutrophils and macrophages after exposure to MM. The results indicated that MM exerted developmental toxicity and immunotoxicity to zebrafish embryos, and these phenomena may be caused by MM's regulation of WNT signaling pathway.

Genistein-induced Anticancer Effects on Acute Leukemia Cells Involve the Regulation of Wnt Signaling Pathway Through H4K20me1 Rather Than DNA Demethylation

ObjectiveTo investigate the effects and mechanisms of genistein on the gene expression in the Wnt pathway in acute leukemia (AL) cells.MethodsThe expression of Wnt pathway genes and cell cycle-related genes were analyzed in two AL cell lines. Pyrophosphate sequencing was performed to determine the methylation degree. Then, the enrichment of H4K20me1 and H3K9ac was determined using ChIP-qPCR. Flow cytometry was used to analyze the cell cycle.ResultsThe IC50 of genistein in the two AL cell lines was lower than that for the bone marrow mesenchymal stem cell line. Genistein upregulated H4K20me1, KMT5A and Wnt suppressor genes, including Wnt5a, and downregulated the downstream target genes of Wnt, such as c-myc and β-catenin. The methylation degree and H3K9ac enrichment in the Wnt5a promoter region remained unchanged. However, the enrichment of H4K20me1 in the Wnt5a promoter and coding regions increased. In addition, genistein upregulated Phospho-cdc2, Myt1, Cyclin A, Cyclin E2, p21 and Phospho-histone H3, but downregulated Phospho-wee1. Cell cycle arrest was induced in the G2/M phase.ConclusionGenistein inhibits the activation of the Wnt pathway by promoting the expression of Wnt5a through the activation of KMT5A and enrichment of H4K20me1 in the Wnt5a gene promoter and coding regions, rather than demethylation. Genistein also blocks the cell cycle in the G2/M phase. Therefore, genistein is a potential anti-leukemia drug.

Bmi1 Regulates Wnt Signaling in Hematopoietic Stem and Progenitor Cells.

Polycomb group protein Bmi1 is essential for hematopoietic stem cell (HSC) self-renewal and terminal differentiation. However, its target genes in hematopoietic stem and progenitor cells are largely unknown. We performed gene expression profiling assays and found that genes of the Wnt signaling pathway are significantly elevated in Bmi1 null hematopoietic stem and progenitor cells (HSPCs). Bmi1 is associated with several genes of the Wnt signaling pathway in hematopoietic cells. Further, we found that Bmi1 represses Wnt gene expression in HSPCs. Importantly, loss of β-catenin, which reduces Wnt activation, partially rescues the HSC self-renewal and differentiation defects seen in the Bmi1 null mice. Thus, we have identified Bmi1 as a novel regulator of Wnt signaling pathway in HSPCs. Given that Wnt signaling pathway plays an important role in hematopoiesis, our studies suggest that modulating Wnt signaling may hold potential for enhancing HSC self-renewal, thereby improving the outcomes of HSC transplantation.

Expression of TCF3 in Wilms' tumor and its regulatory role inkidney tumor cell viability, migration and apoptosis invitro.

Wilms' tumor (WT) is a major type of kidney cancer in children; however, the therapeutic measures for control of tumor metastasis, recurrence and death for this type of cancer remain unsatisfactory. The present study aimed to verify the expression of T-cell factor 3 (TCF3) in WT, and to explore its role in regulating the viability, migration and apoptosis of kidney tumor cells. Tumor tissues were collected from 10 patients with WT, and adjacent tissues were collected as normal controls. The expression levels of TCF3 were detected in WT tissues and adjacent tissues by reverse transcription-quantitative PCR (RT-qPCR), western blotting and immunohistochemistry. In addition, TCF3 expression was silenced in G401 kidney tumor cells via small interfering RNA transfection. Cell viability, cell cycle progression and cell apoptosis were assessed using the MTT assay and flow cytometry; the migration and invasion of kidney tumor cells were examined using Transwell and wound-healing assays; and the expression levels of Wnt signaling pathway-related genes (Wnt1, β-catenin and c-myc) were detected by RT-qPCR and western blotting. The results revealed that the expression levels of TCF3 were high in WT tissues from patients. Silencing TCF3 expression in G401 kidney tumor cells in vitro significantly inhibited cell viability and migration, and promoted cell apoptosis. Moreover, silencing TCF3 expression in G401 cells inhibited the expression levels of Wnt signaling pathway-related genes. Overall, these data indicated that TCF3 may be involved in WT development through regulation of Wnt signaling pathways. The findings of the present study provide a novel potential marker for the treatment and prognostic evaluation of WT.

Abstract 2316: Analysis of APC-1B promoter region responsible for familial adenomatous polyposis

Abstract APC (APC regulator of WNT signaling pathway) is not only a gene responsible for familial adenomatous polyposis (FAP), a hereditary disease characterized by hundreds or thousands adenomatous polyps in the colon, but also plays a crucial role in sporadic human cancers. Although most of FAP cases are caused by germline mutations in the coding region of APC, deletions or point mutations in the promoter regions are involved in a limited number of cases. Previously, we reported an FAP case with a large deletion of approximately 10 kb encompassing APC promoter 1B and exon1B of the APC gene. Since precise regulatory mechanism(s) of the transcription of APC remains to be clarified, we searched in this study the regulatory domain(s) in the deleted region. First, we performed cap analysis of gene expression (CAGE) analysis, and compared the amount of APC-1A and APC-1B transcripts in the peripheral blood cells of the patient with that of healthy volunteers. As a result, we found that the deletion decreased the amount of APC-1B to 39% - 45% in the patient compared to the healthy controls, and that it did not change the amount of APC-1A in the patient. In addition, an allele-specific expression analysis by deep cDNA sequencing revealed that the amount of APC transcripts from the mutated APC allele is reduced to 11.2% by the deletion in the patient, suggesting that the deletion resulted in the marked decrease of the transcription of the affected allele and that the remaining expression of deleted allele may be driven by other regulatory region(s) such as promoter 1A. Consistently, CAGE analysis demonstrated that APC-1B transcripts are more abundantly expressed than APC-1A transcripts in all tissues tested except for the brain, suggesting that promoter 1B plays a crucial role in the expression of APC transcription. Analysis of promoter 1B by reporter assay identified a critical region for the transcriptional activation between -117 bp and -49 bp of promoter 1B. These data will contribute to the better understanding of regulatory mechanisms of APC transcription and the evaluation of genetic variants located in promoter 1B. Citation Format: Saya Nakagawa, Kiyoshi Yamaguchi, Kimiko Saito, Kiyoko Takane, Tsuneo Ikenoue, Yoichi Furukawa. Analysis of APC-1B promoter region responsible for familial adenomatous polyposis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2316.

The Novel Tumor Suppressor Gene ZNF24 Induces THCA Cells Senescence by Regulating Wnt Signaling Pathway, Resulting in Inhibition of THCA Tumorigenesis and Invasion.

ObjectClinically, the effective treatment options available to thyroid cancer (THCA) patients are very limited. Elucidating the features of tumor suppressor genes (TSGs) and the corresponding signal transduction cascade may provide clues for the development of new strategies for targeted therapy of THCA. Therefore, this paper aims to explore the mechanism of ZNF24 underlying promoting THCA cell senescence at molecular level.MethodsWe performed RT-PCR and Western Blotting for evaluating associated RNA and protein expression. CCK8, colony forming, wound healing and Transwell chamber assays were conducted to examine THCA cell proliferation, invasion and migration. β-galactosidase staining assay was performed to detect THCA cells senescence. The size and volume of xenotransplanted tumors in nude mice are calculated to asses ZNF24 effect in vivo.ResultsEctopic expression of ZNF24 significantly inhibited the cell viability, colony forming, migration and invasion abilities of THCA cell lines (K1/GLAG-66i and BCPAPi) (P < 0.05). ZNF24 induced BCPAPi cells senescence through regulating Wnt signaling pathway. ZNF24 inhibited Wnt signaling pathway activition by competitively binding β-catenin from LEF1/TCF1-β-catenin complex. In nude mice, both Ectopic expression of ZNF24 and 2,4-Da (the strong β-catenin/Tcf-4 inhibitor) treatment significantly decreased both the size and weight of xenotransplanted tumors when compared with control mice (P < 0.05).ConclusionResults obtained in vivo and in vitro reveal the role of ZNF24 in significantly suppressing THCA tumorigenesis and invasion by regulating Wnt signaling pathway.

Colon Crypts of Subjects With Familial Adenomatous Polyposis Show an Increased Number of LGR5+ Ectopic Stem Cells.

INTRODUCTION:Familial adenomatous polyposis (FAP) is a hereditary colorectal cancer (CRC) syndrome characterized by accelerated adenoma development due to inherited (or de novo) mutations in the APC regulator of WNT signaling pathway (APC) gene. The mechanism underlying this accelerated polyp development in subjects with FAP has not been defined. Given that LGR5+ stem cells drive crypt cell proliferation, we hypothesized that FAP crypts would demonstrate aberrant leucine-rich repeat–containing G-protein–coupled receptor 5 (LGR5) staining patterns.METHODS:Biopsies were taken from 11 healthy subjects, 7 subjects with Lynch syndrome, 4 subjects with FAP, and 1 subject with MUTYH-associated polyposis syndrome during routine screening or surveillance colonoscopy. Crypt staining was evaluated by immunohistochemistry of paraffin-embedded tissue sections. Stem cell numbers were estimated by immunofluorescence staining of isolated crypts using antibodies against LGR5 and other proteins.RESULTS:Subjects with FAP exhibited a greater number of LGR5+ stem cells in their crypts than healthy subjects and subjects with Lynch syndrome and MUTYH-associated polyposis syndrome. Most crypts of subjects with FAP harbored LGR5+ cells located above the lower third of the crypts.DISCUSSION:These findings support a model in which inactivation of one copy of APC leads to increased numbers of LGR5+ stem cells, many of which are ectopic, in colon crypts of subjects with FAP. Overabundant and ectopic LGR5+ stem cells could lead to an expanded proliferative zone of dividing cells more likely to develop mutations that would contribute to the accelerated adenoma development observed in FAP.

Current Status of MicroRNAs that Target the Wnt Signaling Pathway in Regulation of Osteogenesis and Bone Metabolism: A Review.

The directional differentiation of bone mesenchymal stem cells (BMSCs) is regulated by a variety of transcription factors and intracellular signaling pathways. In the past, it was thought that the directional differentiation of BMSCs was related to transforming growth factors, such as bone morphogenetic protein (BMP) and MAPK pathway. However, in recent years, some scholars have pointed out that the Wnt signaling pathway, which is a necessary complex network of protein interactions for biological growth and development, takes a significant role in this process and plays a major part in regulating the development of osteoblasts by exerting signal transduction into cells. Also, they have proved the Wnt protein therapeutic truly have positive effects on the viability and osteogenic capacity of bone graft. Recent studies have shown that microRNAs (miRNAs) play an important regulatory role in this process. MiRNAs such as miRNA-218, miRNA-335, miRNA-29, microRNA-30 and other miRNAs exert negative or positive effects on some crucial molecules in the Wnt/β-catenin pathway, which in turn affect bone metabolism and osteopathy. Thus, miRNAs have been suggested as therapeutic targets for some metabolic bone diseases. This article aims to provide an update on the current status of microRNAs that target the Wnt signaling pathway in the regulation of osteogenesis and bone metabolism and includes a discussion of future areas of research, which can be a theoretical basis for bone metabolism-related diseases.

Loss of Apc Cooperates with Activated Oncogenes to Induce Liver Tumor Formation in Mice

Hepatocellular carcinoma (HCC) and hepatoblastoma are the major types of primary liver cancer in adulthood and childhood, respectively. Wnt/β-catenin signaling deregulation is one of the most frequent genetic events in hepatocarcinogenesis. APC regulator of WNT signaling pathway (APC) encodes an inhibitor of the Wnt cascade and acts as a tumor suppressor. Germline defects of the APC gene lead to familial adenomatous polyposis, and its somatic mutations occur in multiple tumor types. However, the contribution of APC in hepatocarcinogenesis remains unclear. Therefore, APC mutations and expression patterns were examined in human HCC and hepatoblastoma samples. Whether loss of Apc alone or in cooperation with other oncogenes triggers liver tumor development invivo was also investigated. sgApc alone could not drive liver tumor formation, but synergized with activated oncogenes (YapS127A, TazS89A, and c-Met) to induce hepatocarcinogenesis. Mechanistically, Apc deletion induced the activation of β-catenin and its downstream targets in mouse liver tumors. Furthermore, Ctnnb1 ablation or TCF4-mediated transcription blockade completely prevented liver tumor formation, indicating the requirement of a functional β-catenin pathway for loss of Apc-driven hepatocarcinogenesis. This study shows that a subset of HCC patients with loss-of-function APC mutations mightbenefit from therapeutic strategies targeting the Wnt/β-catenin pathway.

Regulation of Wnt Signaling Pathways at the Plasma Membrane and Their Misregulation in Cancer.

Wnt signaling is one of the key signaling pathways that govern numerous physiological activities such as growth, differentiation and migration during development and homeostasis. As pathway misregulation has been extensively linked to pathological processes including malignant tumors, a thorough understanding of pathway regulation is essential for development of effective therapeutic approaches. A prominent feature of cancer cells is that they significantly differ from healthy cells with respect to their plasma membrane composition and lipid organization. Here, we review the key role of membrane composition and lipid order in activation of Wnt signaling pathway by tightly regulating formation and interactions of the Wnt-receptor complex. We also discuss in detail how plasma membrane components, in particular the ligands, (co)receptors and extracellular or membrane-bound modulators, of Wnt pathways are affected in lung, colorectal, liver and breast cancers that have been associated with abnormal activation of Wnt signaling. Wnt-receptor complex components and their modulators are frequently misexpressed in these cancers and this appears to correlate with metastasis and cancer progression. Thus, composition and organization of the plasma membrane can be exploited to develop new anticancer drugs that are targeted in a highly specific manner to the Wnt-receptor complex, rendering a more effective therapeutic outcome possible.

Expression and prognostic significance of NKD2 in ovarian cancer.

Naked2 (NKD2) is a negative regulator of Wnt signaling pathway and associates with transforming growth factor secretion. The role of NKD2 in ovarian cancer is unknown. Gene expression profiles were measured and compared in nine patients by RNA sequencing. NKD2 expressions in ovarian cancer were measured by reverse transcription polymerase chain reaction and western blot. Tissue slides of 79 patients were stained and scored for NKD2 expression. In vitro experiments were conducted to explore the role of NKD2 in ovarian cancer. The prognostic role of NKD2 was evaluated by survival analysis. NKD2 was upregulated in patients with better survival by mRNA and protein expression. Patients were classified as NKD2-high group (n = 30) and NKD2-low group (n = 49) according to immunohistochemical score. High NKD2 was correlated with lower recurrence rate (P = 0.002) and higher percentage of platinum-sensitive recurrence (P = 0.006). Median progression-free survival was significantly longer for NKD2-high patients than NKD2-low patients (49.1 vs.14.1months, P < 0.001). Accordingly, there was a significantly difference in terms of overall survival time between two groups (hazard ratio: 3.04; 95% confidence interval: 1.58-5.85, P < 0.001). Multivariate regression suggested that NKD2 was independently prognostic factors in terms of progression-free survival (hazard ratio: 2.91; 95% confidence interval: 1.61-5.27, P < 0.001) and overall survival (hazard ratio: 3.6; 95% confidence interval: 1.80-7.21, P < 0.001). In vitro studies further demonstrated that NKD2 suppressed ovarian cancer cell proliferation, colony formation and cell migration. NKD2 is a novel prognostic marker and could suppress tumor progression in ovarian cancer.

TMEM132A, a Novel Wnt Signaling Pathway Regulator Through Wntless (WLS) Interaction.

Wnt signaling pathway plays indispensable roles in embryonic development and adult tissue homeostasis. However, the regulatory mechanisms involved in Wnt ligand trafficking within and secretion from the signal sending cells is still relatively uncharacterized. Here, we discover a novel regulator of Wnt signaling pathway called transmembrane protein 132A (TMEM132A). Our evidence shows a physical and functional interaction of TMEM132A with the Wnt ligand transporting protein Wntless (WLS). We show that TMEM132A stabilizes Wnt ligand, enhances WLS–Wnt ligand interaction, and activates the Wnt signaling pathway. Our results shed new light on the cellular mechanism underlying the fundamental aspect of WNT secretion from Wnt signal sending cells.

Transcriptomic Analysis Revealed an Emerging Role of Alternative Splicing in Embryonal Tumor with Multilayered Rosettes.

Embryonal tumor with multilayered rosettes (ETMR) is an aggressive and rare pediatric embryonal brain tumor. Amplification of C19MC microRNA cluster and expression of LIN28 are distinctive features of ETMR. Despite the increasing efforts to decipher ETMR, the biology remains poorly understood. To date, the role of aberrant alternative splicing in ETMR has not been thoroughly investigated. In the current study, a comprehensive analysis was performed on published unprocessed RNA-seq reads of tissue-matched ETMR and fetal controls datasets. Gene expression was quantified in samples using Kallisto/sleuth pipeline. For the alternative splicing analysis, STAR, SplAdder and rMATS were used. Functional enrichment analysis was subsequently performed using Metascape. The expression analysis identified a total of 3622 differentially expressed genes (DEGs) between ETMR and fetal controls while 1627 genes showed differential alternative splicing patterns. Interestingly, genes with significant alternative splicing events in ETMR were identified to be involved in signaling pathways such as ErbB, mTOR and MAPK pathways as well as ubiquitin-mediated proteolysis, cell cycle and autophagy. Moreover, up-regulated DEGs with alternative splicing events were involved in important biological processes including nuclear transport, regulation of cell cycle and regulation of Wnt signaling pathway. These findings highlight the role of aberrant alternative splicing in shaping the ETMR tumor landscape, and the identified pathways constitute potential therapeutic targets.

MiR-640 inhibition alleviates acute liver injury via regulating WNT signaling pathway and LRP1.

Acute liver injury (ALI) is associated with the Kupffer cells (KCs) inflammation and hepatocytes apoptosis. Previous studies have shown that miR-640 is a valid regulator of the Low-density lipoprotein receptor-related protein 1 (LRP 1) which expressed much lower in an inflammatory condition. However, it is unclear whether MiR-640 inhibition protects against ALI by the up-regulation of LRP 1. To explore the regulated mechanism of miR-640 on acute liver injury. We analyzed the expression of miR-640 in different times of acute injured liver tissues. Lipopolysaccharide (LPS) was employed in provoking the KCs inflammation to injure liver. We used miR-640 mimic or inhibitor to improve or resist the function of miR-640 to explore miR-640 function to ALI via the target of LRP1. We showed that the expression of miR-640 markedly increased in LPS-induced acute injured liver tissues. LPS promoted the progress of ALI, and the inhibition of miR-640 could reverse the injured effects of LPS. Moreover, WNT signaling pathway and LRP1 were significantly enhanced by miR-640 inhibition. These results suggested that miR-640 promotes KCs inflammation via restraining LRP 1 and WNT signaling pathway. But inhibiting miR-640 prevents inflammation damage and ameliorates ALI. MiR-640 inhibition may become a novel target for the therapy of ALI in the future.

Erratum.

Erratum.

Abstract 4735: Oncogenic involvement of NF-kB signaling pathway in glioma

Abstract Introduction: Aberrant activity of NF-kB has been observed across several cancer types. The current understanding is that the constitutive activation of NF-kB enhances the expression of genes that promote cell proliferation as well as prevent cells from apoptosis. Previous studies have shown that, compared with other cancer types, glioma appears with much significant over-expression of NF-kB. This implies that glioma may be a better subject to elucidate the activity of NF-kB during tumorigenesis. Here we present an analysis aiming to characterize the oncogenic involvement of NF-kB in glioma. Method: We retrieved RNA-Seq expression data of glioblastoma (GBM), low-grade glioma (LGG) as well as other seven major cancer types from TCGA repository. In addition, we collected a total number of 120 tumor samples comprising of 80 GBM and 40 LGG. RNA-Seq experiment was carried out according to standard protocol. Data quality was assessed at multiple steps. In correlation analysis, a number of oncogenic and immune genes / pathways were empirically pre-defined. Pearson coefficient was measured. Expression enrichment analysis was performed using either GSEA or ssGSEA. Immune cell infiltration was assessed using ESTIMATE. Results and conclusion: Pan-cancer analysis shown that, compared with peripheral non-tumor tissue, all five NF-kB member genes, NFKB1, NFKB2, REL, RELA and RELB, are significantly up-regulated in tumor tissue of GBM and LGG, but not in other cancer types. Except previously reported association with EGFR mutation, we also observed that TP53 mutation significantly correlates with over-expression of NF-kB in LGG. CDKN2A and CDKN2B deletion moderately correlate with over-expression of NFKB1,RELB and REL. In addition, RAS and ERBB signaling pathway positively correlates with NF-kB pathway in both GBM and LGG. This is consistent with established cross-talk between these genes. WNT signaling pathway positively correlates with NF-kB in GBM while negatively correlates with NF-kB in LGG. NF-kB regulates WNT signaling through LZTS2 under specific physiological conditions. Our results shown that LZTS2 is up-regulated in LGG while down-regulated in GBM suggesting that NF-kB regulates WNT through LZTS2 in a bidirectional manner. In regulating immune environment, NF-kB expression positively correlates with major immune infiltrates as well as cytokines responsible for modulating the penetrance of blood-brain barrier (BBB), indicating that NF-kB recruit immune cells in response to stimuli in brain despite the existence of BBB. In sum, NF-kB seems to impose rather similar impact on glioma as on other non-CNS solid tumor, i.e. recruitment of immune infiltrates. On the other hand, NF-kB behaves differently in regulating WNT signaling pathway in GBM and LGG. How differential activation of WNT signaling eventually contributes to phenotypical difference between GBM and LGG is to be investigated in further studies Citation Format: Cheng Yan, Lan Su, Xin Qi, Yufei Yang, Jun Wu. Oncogenic involvement of NF-kB signaling pathway in glioma [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 4735.