ETV4 facilitates proliferation, migration, and invasion of liver cancer by mediating TGF-β signal transduction through activation of B3GNT3

BACKGROUND

Metastasis of liver cancer (LC) is the main cause of its high mortality. ETV4 is a critical regulatory factor in promoting LC progression, but the mechanism that ETV4 impacts LC proliferation, migration, and invasion is poorly understood.

OBJECTIVE

Investigation of the molecular mechanism of LC metastasis is conducive to developing effective drugs that prevent LC metastasis.

METHODS

Expression of ETV4 and its target gene B3GNT3 in LC tissue was analyzed by bioinformatics, and the result was further verified in LC cells by qRT-PCR. In vitro cellular assays evaluated the impact of ETV4 on the proliferation, migration, and invasion of LC cells. Chromatin immunoprecipitation (ChIP) and dual-luciferase reporter gene assay were conducted to analyze the interaction between B3GNT3 and ETV4. SB525334 suppressor was used to treat and access the activation of ETV4 on the TGF-β pathway.

RESULTS

We discovered that ETV4 and B3GNT3 were evidently up-regulated in LC, and high expression of ETV4 was coupled to the increase of proliferation, migration, and invasion of LC cells and epithelial-mesenchymal transition ability. Besides, ETV4 could bind to the B3GNT3 promoter and activate its transcription. Knockdown of B3GNT3 could prominently suppress the effect of up-regulated ETV4 on LC cells. Meanwhile, ETV4 could activate the TGF-β signaling pathway via B3GNT3, while SB525334 treatment notably repressed the functions of ETV4.

CONCLUSION

ETV4 emerges as a driven oncogene in LC, and the ETV4/B3GNT3-TGF-β pathway promotes proliferation, migration, invasion, and epithelial-mesenchymal transition progress of LC. Inhibition of the pathway may provide an underlying method for the prevention and treatment of LC metastasis.

Ladinin 1 Shortens Survival via Promoting Proliferation and Enhancing Invasiveness in Lung Adenocarcinoma

Lung cancer is one of the deadliest cancers worldwide, including in Taiwan. The poor prognosis of the advanced lung cancer lies in delayed diagnosis and non-druggable targets. It is worth paying more attention to these ongoing issues. Public databases and an in-house cohort were used for validation. The KM plotter was utilized to discover the clinical significance. GSEA and GSVA were adopted for a functional pathway survey. Molecular biological methods, including proliferation, migration, and the EMT methods, were used for verification. Based on public databases, the increased expression of Ladinin 1 (LAD1) was presented in tumor and metastatic sites. Furthermore, an in-house cohort revealed a higher intensity of LAD1 in tumor rather than in normal parts. The greater the expression of LAD1 was, the shorter the duration of lung adenocarcinoma (LUAD) patient survival. Moreover, the association of B3GNT3 with LAD1 affected the survival of LUAD patients. Functional analyses using GSEA and GSVA revealed the associations with survival, migration, invasion, and EMT. Biologic functions supported the roles of LAD1 in proliferation via the cell cycle and migration in EMT. This study reveals that LAD1 plays a major role in regulating proliferation and migration in lung cancer and impacts survival in LUAD. It is worth investing in further studies and in the development of drugs targeting LAD1.

B3GNT3 as a prognostic biomarker and correlation with immune cell infiltration in lung adenocarcinoma

Background

Lung adenocarcinoma (LUAD) is the most common malignant cancer in humans and because of low long-term survival rates, exploration of the molecular mechanisms underlying its progression, as well as novel prognostic predictors, is urgently needed. B3GNT3, a type II transmembrane protein located in the Golgi apparatus, is essential for forming extended core 1 oligosaccharides and is reportedly involved in malignant transformation.

Methods

The Cancer Genome Atlas (TCGA) and GSE68465 were used to analyze the expression of B3GNT3 in LUAD and normal tissues and overall survival. Real time quantitative polymerase chain reaction (qPCR) and western blot were conducted to measure the mRNA and protein levels of B3GNT3, respectively. Functional enrichment of differentially expressed genes was explored using Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses. We performed univariate and multivariate Cox regression analyses and a meta-analysis to reveal an independent factor for LUAD. We evaluated the correlation between immune infiltration levels and cumulative survival in the TIMER database. The correlation between B3GNT3 and immune cell infiltration was assessed via Cell-type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT). The association of DNA methylation of B3GNT3 and prognosis was determined. A nomogram that incorporated expression and clinical features was additionally built for prognostic prediction. Cell proliferation, cloning, and invasion were conducted to validate the roles of B3GNT3 in LUAD.

Results

B3GNT3 was more highly expressed in LUAD tissues than in normal lung tissues, consistent with the mRNA and protein levels in LUAD cells. B3GNT3 was an independent factor for LUAD. Moreover, the levels of B3GNT3 were related to immune cell infiltration in LUAD microenvironments. DNA methylation of B3GNT3 correlated with the mRNA of B3GNT and overall survival of LUAD patients. The expression of B3GNT3 was highly valuable for the prediction of diagnosis. Knockdown of B3GNT3 inhibited LUAD cell viability and cloning ability, and hindered invasion.

Conclusions

B3GNT3 was highly associated with immune cell infiltration, acting as an important biomarker for the prognosis and diagnosis of LUAD.

B3GNT3 overexpression promotes tumor progression and inhibits infiltration of CD8+ T cells in pancreatic cancer

Beta-1,3-N-acetylglucosaminyltransferase 3 (B3GNT3) has been associated with tumor progression in several solid tumors, and inhibits CD8⁺ T cell-mediated anti-tumor immunity in breast cancer. However, little is known about the potential functions of B3GNT3 in immunosuppression in pancreatic cancer (PC). This study on B3GNT3 aims to provide novel insights into the mechanisms of immune suppression or evasion in PC. To this end, the clinical significance and oncologic roles of B3GNT3 were investigated through bioinformatic analysis and in vitro studies. Potential associations between the expression of B3GNT3 and tumor immunity were mainly analyzed by single-sample gene set enrichment analysis (ssGSEA) and immunofluorescence in tissue microarray (TMA). B3GNT3 overexpression was observed in PC tissue and was associated with larger tumor sizes, higher histologic grades, and poorer overall survival (OS). B3GNT3 overexpression was associated with the mutation status and expression of driver genes, especially for KRAS and SMAD4. B3GNT3 knockdown inhibited the proliferation, invasion, and epithelial-mesenchymal transition (EMT) of PC cells. B3GNT3 overexpression significantly correlated with decreased infiltration of tumor infiltrating lymphocytes (TILs), especially CD8⁺ T cells. Overall, our results indicate that B3GTN3 plays a novel role in tumor progression and immunosuppression, thus serving as a potential therapeutic target in PC.

B3GNT3, a Direct Target of miR-149-5p, Promotes Lung Cancer Development and Indicates Poor Prognosis of Lung Cancer

Background

B3GNT3 (β1, 3-N-acetylglucosaminyltransferase-3) belongs to the β3GlcNAcT family and is essential to form extended core 1 oligosaccharides. Previous studies revealed that B3GNT3 expression was dysregulated in multiple cancers. Here, we aimed to understand the expression profile and function of B3GNT3 in lung cancer.

Materials and Methods

The expression of B3GNT3 was measured by immunohistochemistry and public database analysis. B3GNT3 was knocked down to evaluate the lung cancer cell proliferation, migration and invasion in in vitro and in vivo tumor formation experiments. miR-149-5p targeting B3GNT3 was identified with TargetScan analysis and confirmed with reporter assay. Overexpression of miR-149-5p was achieved using microRNA mimics and function of microRNA-149-5p/B3GNT3 axis was tested in vitro.

Results

B3GNT3 was upregulated in lung cancer, and B3GNT3 overexpression was associated with poor prognosis of lung cancer patients. High expression of B3GNT3 was associated with advanced TNM stages, larger tumor size, tumor metastasis and recurrence. Functionally, we demonstrated that knockdown of B3GNT3 suppressed lung cancer cell growth and invasion in vitro. Knockdown of B3GNT3 suppressed lung cancer development in a xenograft tumor model. Moreover, miR-149-5p was validated to negatively regulate B3GNT3 expression through directly targeting B3GNT3 3ʹ-UTR. Overexpression of miR-149-5p could antagonize the tumorigenesis effect of B3GNT3 in vitro.

Conclusion

In summary, our study demonstrated that B3GNT3 overexpression was correlated with poor prognosis of lung cancer patient, indicating that B3GNT3 could be a promising prognostic biomarker for lung cancer. miR-149-5p negatively regulated B3GNT3 expression, which might be utilized for therapeutic target in lung cancer.

Novel role of O-glycosyltransferases GALNT3 and B3GNT3 in the self-renewal of pancreatic cancer stem cells

BACKGROUND

Glycosylation plays a critical role in the aggressiveness of pancreatic cancer (PC). Emerging evidences indicate significant involvement of cancer stem cells (CSCs) in PC aggressiveness. However, the importance of glycosylation in pancreatic cancer stem cells (PCSCs) is yet to be addressed. Hence, we evaluated the potential role of glycosylation in maintenance of stemness of PCSCs.

METHODS

Effect of glycosylation specific inhibitors on growth and PCSCs of PC cells was assessed by MTT assay and Side Population (SP) analysis. Isolated PCSCs/SP were characterized using molecular and functional assays. Expression of tumor-associated carbohydrate antigens (TACAs) was analyzed in PCSCs by western blotting. Effect of tunicamycin on PCSCs was analyzed by tumorsphere, clonogenicity, migration assay and immunoblotting for CSCs markers. The differential expression of glycogenes in PCSCs compared to non-CSCs were determined by RT-qPCR, immunoblotting and immunofluorescence. Co-expression of GALNT3 and B3GNT3 with CD44v6 was assessed in progression stages of KrasG12D; Pdx-1-Cre (KC) and KrasG12D; p53R172H; Pdx-1-Cre (KPC) tumors by immunofluorescence. Transient and CRISPR/Cas9 silencing of GALNT3 and B3GNT3 was performed to examine their effect on CSCs maintenance.

RESULTS

Inhibition of glycosylation decreased growth and CSCs/SP in PC cells. PCSCs overexpressed CSC markers (CD44v6, ESA, SOX2, SOX9 and ABCG2), exhibited global expressional variation of TACAs and showed higher self-renewal potential. Specifically, N-glycosylation inhibition, significantly decreased tumorsphere formation, migration, and clonogenicity of PCSCs, as well as hypo-glycosylated CD44v6 and ESA. Of note, glycosyltransferases (GFs), GALNT3 and B3GNT3, were significantly overexpressed in PCSCs and co-expressed with CD44v6 at advanced PDAC stages in KC and KPC tumors. Further, GALNT3 and B3GNT3 knockdown led to a decrease in the expression of cell surface markers (CD44v6 and ESA) and self-renewal markers (SOX2 and OCT3/4) in PCSCs. Interestingly, CD44v6 was modified with sialyl Lewis a in PCSCs. Finally, CRISPR/Cas9-mediated GALNT3 KO significantly decreased self-renewal, clonogenicity, and migratory capacity in PCSCs.

CONCLUSIONS

Taken together, for the first time, our study showed the importance of glycosylation in mediating growth, stemness, and maintenance of PCSCs. These results indicate that elevated GALNT3 and B3GNT3 expression in PCSCs regulate stemness through modulating CSC markers.

Eradication of Triple-Negative Breast Cancer Cells by Targeting Glycosylated PD-L1

Protein glycosylation provides proteomic diversity in regulating protein localization, stability, and activity; it remains largely unknown whether the sugar moiety contributes to immunosuppression. In the study of immune receptor glycosylation, we showed that EGF induces programmed death ligand 1 (PD-L1) and receptor programmed cell death protein 1 (PD-1) interaction, requiring β-1,3-N-acetylglucosaminyl transferase (B3GNT3) expression in triple-negative breast cancer. Downregulation of B3GNT3 enhances cytotoxic T cell-mediated anti-tumor immunity. A monoclonal antibody targeting glycosylated PD-L1 (gPD-L1) blocks PD-L1/PD-1 interaction and promotes PD-L1 internalization and degradation. In addition to immune reactivation, drug-conjugated gPD-L1 antibody induces a potent cell-killing effect as well as a bystander-killing effect on adjacent cancer cells lacking PD-L1 expression without any detectable toxicity. Our work suggests targeting protein glycosylation as a potential strategy to enhance immune checkpoint therapy.