FRZB knockdown upregulates β-catenin activity and enhances cell aggressiveness in gastric cancer

Integrative analysis of anoikis-related prognostic signature to evaluate the immune landscape and predict therapeutic response in stomach adenocarcinoma

Stomach adenocarcinoma (STAD) is the most prevalent gastrointestinal malignancy and seriously threatens the life of the global population. Anoikis, a process of programmed cell death that occurs when cells detach from the extracellular matrix, is closely associated with tumor invasion and metastasis. In this study, we used the TCGA-STAD database to identify the expression patterns and prognostic relevance of anoikis-related genes (ARGs) in STAD. Functional enrichment analysis was used to explore the potential pathway. LASSO and Cox regression were used to construct anoikis-related prognostic signature. The anoikis risk score (ARS) incorporated 7 genes and stratified patients into highand low-risk subgroups by median value splitting. In addition, external validation was performed based on GSE66229, GSE15459, and GSE84437 cohorts. Nomograms were created based on risk characteristics in combination with clinical variants and the performance of the model was validated with time-dependent AUC, calibration curves, and decision curve analysis (DCA). The prognostic signature indicated that the low-risk subgroup had better outcomes and significant correlations with tumor microenvironment, immune landscape, immunotherapy response, and drug sensitivity. In addition, single-cell analysis displayed the cell types, the subcellular localization of prognostic genes, and the cellular interaction to reveal the potential molecular communication mechanism of anoikis resistance. Finally, in vitro experiments confirmed the critical role of CRABP2 in STAD. The results indicated that CRABP2 knockdown inhibited gastric cancer cell proliferation, migration and invasion, and promoted apoptosis. In summary, ARS can serve as a biomarker for predicting survival outcomes in STAD patients, providing new tools for personalized treatment decisions for STAD patients.

Modulating vascular smooth muscle cell phenotype via Wnt-Independent FRZB pathways

BACKGROUND AND AIMS

Vascular smooth muscle cells are pivotal in atherosclerosis, transitioning from a contractile to a synthetic phenotype, which is associated with increased proliferation and inflammation. FRZB, a Wnt signaling modulator, has been implicated in vascular pathology, but its specific role in vascular smooth muscle cell phenotype modulation is not well understood. This study investigates the role of FRZB in regulating vascular smooth muscle cell phenotypes.

METHODS

Vascular smooth muscle cell regions were categorized based on FRZB expression levels, and various analyses, including differential gene expression, KEGG pathway analysis, and Disease Ontology analysis, were conducted. FRZB knockdown in human aortic vascular smooth muscle cell was performed using siRNA, followed by assessments of cell migration, proliferation, and phenotype marker expression.

RESULTS

FRZB expression was significantly reduced in synthetic type compared to contractile type in both mouse models and human samples. FRZB knockdown in human vascular smooth muscle cells led to increased cell migration and proliferation, alongside decreased expression of contractile markers and increased synthetic markers. Unexpectedly, FRZB knockdown suppressed Wnt signaling. Pathway analysis revealed associations with the PI3K-Akt signaling pathway, focal adhesion, and ECM interactions.

CONCLUSIONS

Our study highlights FRZB's role in Vascular smooth muscle cell phenotype modulation, showing that reduced FRZB expression correlates with a synthetic phenotype and increased disease markers. FRZB does not enhance Wnt signaling but may regulate vascular smooth muscle cell behavior through alternative pathways. These findings suggest FRZB as a potential therapeutic target for stabilizing vascular smooth muscle cells and managing atherosclerosis.

FRZB affects Staphylococcus aureus‑induced osteomyelitis in human bone marrow derived stem cells by regulating the Wnt/β‑catenin signaling pathway

Osteomyelitis is an infectious disease of bone tissue caused by bacterial infection, which can infect through hematogenous, traumatic or secondary ways and then lead to acute or chronic bone injury and relative clinical symptoms, bringing physical injury and economic burden to patients. Frizzled related protein (FRZB) participates in the regulation of various diseases (osteoarthritis, cardiovascular diseases and types of cancer) by regulating cell proliferation, motility, differentiation and inflammation, while its function in osteomyelitis remains to be elucidated. The present study aimed to uncover the role and underlying mechanism of FRZB mediation in Staphylococcus aureus (S. aureus)-induced osteomyelitis. Human bone marrow derived stem cells (hBMSCs) were treated with S. aureus to imitate an inflammatory osteomyelitis micro-environment in vitro, then mRNA and protein expression were severally assessed by RT-PCR and western blotting. The activity, apoptosis and differentiation of the cells were characterized via CCK-8, caspase-3 activity and Alizarin red sulfate/alkaline phosphatase staining, respectively. Expression levels of FRZB were upregulated in S. aureus-infected hBMSCs. Over-expression of FRZB significantly reduced hBMSC cell viability and differentiation while promoting cell apoptosis with or without S. aureus infection. However, FRZB knockdown reversed these effects. Once Wnt was impeded, the effect of FRZB downregulation was impeded to a great extent. Taken together, FRZB participated to regulate the osteomyelitis by activating the Wnt/β-catenin signaling pathway.

Aberrant expression of SFRP1, SFRP3, DVL2 and DVL3 Wnt signaling pathway components in diffuse gastric carcinoma

Diffuse gastric carcinoma (DGC) is characterized by poorly cohesive cells, highly invasive growth patterns, poor prognosis and resistance to the majority of available systemic therapeutic strategies. It has been previously reported that the Wnt/β-catenin signaling pathway serves a prominent role in the tumorigenesis of gastric carcinoma. However, the mechanism underlying the dysregulation of this pathway in DGC has not been fully elucidated. Therefore, the present study aimed to investigate the expression profiles of Wnt antagonists, secreted frizzled-related protein 1 (SFRP1) and secreted frizzled-related protein 3 (SFRP3), and dishevelled protein family members, dishevelled segment polarity protein 2 (DVL2) and dishevelled segment polarity protein 3 (DVL3), in DGC tissues. The association between the expression levels of these factors and the clinicopathological parameters of the patients was determined. Protein and mRNA expression levels in 62 DGC tumor tissues and 62 normal gastric mucosal tissues obtained from patients with non-malignant disease were measured using immunohistochemical and reverse transcription-quantitative PCR (RT-qPCR) analysis. Significantly lower protein expression levels of SFRP1 (P<0.001) and SFRP3 (P<0.001), but significantly higher protein expression levels of DVL2 (P<0.001) and DVL3 (P<0.001) were observed in DGC tissues compared with in control tissues by immunohistochemistry. In addition, significantly lower expression levels of SFRP1 (P<0.05) and higher expression levels of DVL3 (P<0.05) were found in in DGC tissues compared with those in normal gastric mucosal tissues using RT-qPCR. According to correlation analysis between the SFRP1, SFRP3, DVL2 and DVL3 protein expression levels and the clinicopathological characteristics of patients with DGC, a statistically significant correlation was found between the SFRP3 volume density and T stage (r=0.304; P=0.017) and between the SFRP3 volume density and clinical stage (r=0.336; P=0.008). In conclusion, the findings of the present study suggested that the Wnt signaling pathway components SFRP1, SFRP3, DVL2 and DVL3 may be aberrantly expressed in DGC tissues, implicating their possible role in the development of this malignant disease. The present data also revealed a positive relationship between SFRP3 protein expression and the clinical and T stage of DGC.

CircCNIH4 inhibits gastric cancer progression via regulating DKK2 and FRZB expression and Wnt/β-catenin pathway

Background

Circular RNAs (circRNAs) have been reported to play an important role in tumor progression in various cancer types, including gastric cancer. The aim of this study was to investigate the role of circCNIH4 (hsa_circ_0000190) in gastric cancer and the underlying mechanism.

Methods

The expression levels of circCNIH4 and Wnt antagonist genes were detected by quantitative real-time polymerase chain reaction (qRT-PCR). The protein levels of β-catenin, Ki67, Dickkopf 2 (DKK2) and Frizzled related protein (FRZB) were measured by western blot. Ectopic overexpression or knockdown of circCNIH4, proliferation, apoptosis, migration and invasion by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry and transwell assay in vitro, and in vivo experiment, were employed to assess the role of circCNIH4 in gastric cancer.

Results

CircCNIH4 was downregulated in gastric cancer tissues and cells. Overexpression of circCNIH4 inhibited gastric cancer cell proliferation, migration and invasion and promoted apoptosis by inactivating Wnt/β-catenin pathway in vitro. CircCNIH4 induced the expression of DKK2 and FRZB in gastric cancer cells. Moreover, silencing of DKK2 or FRZB reversed circCNIH4 overexpression-mediated effects on gastric cancer cells. Additionally, circCNIH4 suppressed tumor growth via regulating DKK2 and FRZB expression in gastric cancer in vivo.

Conclusion

Our study demonstrated that circCNIH4 played a tumor-inhibiting role through upregulating DKK2 and FRZB expression and suppressing Wnt/β-catenin pathway in gastric cancer, which might provide a potential biomarker for the diagnosis and treatment of gastric cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40709-021-00140-x.

Increased expression of the thyroid hormone nuclear receptor TRα1 characterizes intestinal tumors with high Wnt activity

Our previous work demonstrated a key function of the thyroid hormone nuclear receptor TRα1, a T3-modulated transcription factor, in controlling intestinal development and homeostasis via the Wnt and Notch pathways. Importantly, increased expression of TRα1 in the intestinal epithelium in a mutated Apc genetic background (vil-TRα1/Apc^+/1638N mice) accelerated tumorigenesis and contributed to a more aggressive tumor phenotype compared to that of the Apc mutants alone. Therefore, the aim of this study was to determine the relevance of this synergistic effect in human colorectal cancers and to gain insights into the mechanisms involved. We analyzed cohorts of patients by in silico and experimental approaches and observed increased TRα1 expression and a significant correlation between TRα1 levels and Wnt activity. TRα1 loss-of-function and gain-of-function in Caco2 cell lines not only confirmed that TRα1 levels control Wnt activity but also demonstrated the role of TRα1 in regulating cell proliferation and migration. Finally, upon investigation of the molecular mechanisms responsible for the Wnt-TRα1 association, we described the repression by TRα1 of several Wnt inhibitors, including Frzb, Sox17 and Wif1. In conclusion, our results underline an important functional interplay between the thyroid hormone nuclear receptor TRα1 and the canonical Wnt pathway in intestinal cancer initiation and progression. More importantly, we show for the first time that the expression of TRα1 is induced in human colorectal cancers.

Resetting the epigenetic balance of Polycomb and COMPASS function at enhancers for cancer therapy

The lysine methyltransferase KMT2C (also known as MLL3), a subunit of the COMPASS complex, implements monomethylation of Lys4 on histone H3 (H3K4) at gene enhancers. KMT2C (hereafter referred to as MLL3) frequently incurs point mutations across a range of human tumor types, but precisely how these lesions alter MLL3 function and contribute to oncogenesis is unclear. Here we report a cancer mutational hotspot in MLL3 within the region encoding its plant homeodomain (PHD) repeats and demonstrate that this domain mediates association of MLL3 with the histone H2A deubiquitinase and tumor suppressor BAP1. Cancer-associated mutations in the sequence encoding the MLL3 PHD repeats disrupt the interaction between MLL3 and BAP1 and correlate with poor patient survival. Cancer cells that had PHD-associated MLL3 mutations or lacked BAP1 showed reduced recruitment of MLL3 and the H3K27 demethylase KDM6A (also known as UTX) to gene enhancers. As a result, inhibition of the H3K27 methyltransferase activity of the Polycomb repressive complex 2 (PRC2) in tumor cells harboring BAP1 or MLL3 mutations restored normal gene expression patterns and impaired cell proliferation in vivo. This study provides mechanistic insight into the oncogenic effects of PHD-associated mutations in MLL3 and suggests that restoration of a balanced state of Polycomb-COMPASS activity may have therapeutic efficacy in tumors that bear mutations in the genes encoding these epigenetic factors.

Gene expression profiling analysis reveals fur development in rex rabbits (Oryctolagus cuniculus)

Fur is an important economic trait in rabbits. The identification of genes that influence fur development and knowledge regarding the actions of these genes provides useful tools for improving fur quality. However, the mechanism of fur development is unclear. To obtain candidate genes related to fur development, the transcriptomes of tissues from backs and bellies of Chinchilla rex rabbits were compared. Of the genes analyzed, 336 showed altered expression in the two groups (285 upregulated and 51 downregulated, P ≤ 0.05, fold-change ≥2 or ≤0.5). Using GO and KEGG to obtain gene classes that were differentially enriched, we found several genes to be involved in many important biological processes. In addition, we identified several signaling pathways involved in fur development, including the Wnt and MAPK signaling pathways, revealing mechanisms of skin and hair follicle development, and epidermal cell and keratinocytes differentiation. The obtained rabbit transcriptome and differentially expressed gene profiling data provided comprehensive gene expression information for SFRP2, FRZB, CACNG1, SLC25A4, and SLC16A3. To validate the RNA-seq data, the expression levels of eight differentially expressed genes involved in fur development were confirmed by qRT-PCR. The results of rabbit transcriptomic profiling provide a basis for understanding the molecular mechanisms of fur development.

FRZB and melusin, overexpressed in LGMD2A, regulate integrin β1D isoform replacement altering myoblast fusion and the integrin-signalling pathway

Limb-girdle muscular dystrophy type 2A (LGMD2A) is characterised by muscle wasting and progressive degeneration of proximal muscles because of mutations in the CAPN3 gene. However, the underlying pathophysiological mechanisms of muscle degeneration are still not well understood. The objective of this study was to assess the relevance of genes with differential expression in the muscle of LGMD2A patients. For this purpose, we analysed their in vitro expression in primary cultures of human myoblasts and myotubes. Abnormal fusion was observed in the myotubes of these patients, which may be explained by the lack of physiological replacement of integrin β1D. Owing to this observation, we focused on deregulated genes coding proteins that directly interact with integrin, ITGB1BP2 and CD9, as well as FRZB gene, because of its in vitro upregulation in myotubes. Silencing studies established that these genes are closely regulated, CD9 and FRZB being positive regulators of the expression of ITGB1BP2, and in turn, this gene being a negative regulator of the expression of FRZB. Interestingly, we observed that FRZB regulates integrin β1D expression, its silencing increasing integrin β1D expression to levels similar to those in controls. Finally, the administration of LiCl, an enhancer of the Wnt-signalling pathway showed similar experimentally beneficial effects, suggesting FRZB silencing or LiCl administration as potential therapeutic targets, though further studies are required.

Integrated Analysis Identifies Molecular Signatures and Specific Prognostic Factors for Different Gastric Cancer Subtypes

BACKGROUND

Gastric cancer (GC) is the fifth leading cause of cancer-related deaths worldwide. As an effective and easily performed method, microscopy-based Lauren classification has been widely accepted by gastrointestinal surgeons and pathologists for GC subtyping, but molecular characteristics of different Lauren subtypes were poorly revealed.

METHODS

GSE62254 was used as a derivation cohort, and GSE15459 was used as a validation cohort. The difference between diffuse and intestinal GC on the gene expression level was measured. Gene ontology (GO) enrichment analysis was performed for both subgroups. Hierarchical clustering and heatmap exhibition were also performed. Kaplan-Meier plot and Cox proportional hazards model were used to evaluate survival grouped by the given genes or hierarchical clusters.

RESULTS

A total of 4598 genes were found differentially expressed between diffuse and intestinal GC. Immunity- and cell adhesion-related GOs were enriched for diffuse GC, whereas DNA repair- and cell cycle-related GOs were enriched for intestinal GC. We proposed a 40-gene signature (χ2=30.71, P<.001) that exhibits better discrimination for prognosis than Lauren classification (χ2=12.11, P=.002). FRZB [RR (95% CI)=1.824 (1.115-2.986), P=.017] and EFEMP1 [RR (95% CI)=1.537 (0.969-2.437), P=.067] were identified as independent prognostic factors only in diffuse GC but not in intestinal GC patients. KRT23 [RR (95% CI)=1.616 (0.938-2.785), P=.083] was identified as an independent prognostic factor only in intestinal GC patients but not in diffuse GC patients. Similar results were achieved in the validation cohort.

CONCLUSION

We found that GCs with different Lauren classifications had different molecular characteristics and identified FRZB, EFEMP1, and KRT23 as subtype-specific prognostic factors for GC patients.