Distribution of serum Thrombospondin-2, a novel tumor marker, in general population and cancer patients in China

N6 -methyladenosine RNA demethylase FTO regulates extracellular matrix-related genes and promotes pancreatic cancer cell migration and invasion

Pancreatic cancer (PC) is a deadly disease, and its post-transcriptional gene regulation mechanism remains unclear. The abundant extracellular matrix (ECM) in PC plays an important role in tumor progression. This study is the first to focus on the role of N⁶ -methyladenosine (m⁶ A) RNA methylation, an emerging post-transcriptional regulatory mechanism, in the regulation of the ECM in PC. Here, we found that ADAMTS2, COL12A1, and THBS2 were associated with the prognosis of PC by comprehensive analysis of differentially expressed genes from two independent GEO expression profile datasets and m⁶ A-related genes in RMVar database (PAAD). GO and KEGG enrichment analysis found that these m⁶ A-related targets are chiefly functionally concentrated in the ECM region and participate in ECM signal transduction. Correlation analysis revealed that these genes can be regulated by the demethylase FTO. Cell biology function assays showed that knockdown of FTO-inhibited PC cell abilities to migrate and invade in vitro. qRT-PCR and MeRIP experiments showed that after knockdown of FTO, the mRNA levels of ADAMTS2, COL12A1, and THBS2 and their m⁶ A modification levels were significantly reduced. These results indicate that m⁶ A RNA demethylation is associated with the regulation of ECM in PC. In conclusion, m⁶ A RNA demethylase FTO regulates ECM-related genes and promotes PC cell abilities to migrate and invade, our work provides a new perspective on the molecular mechanism of PC progression.

Thrombospondin-2 acts as a bridge between tumor extracellular matrix and immune infiltration in pancreatic and stomach adenocarcinomas: an integrative pan-cancer analysis

Background

Thrombospondin-2 (THBS2) is a versatile glycoprotein that regulates numerous biological functions, including the apoptosis-proliferation balance in endothelial cells, and it has been linked to tumor angiogenesis. However, the exact role of THBS2 in human cancer remains unknown. This study aimed to determine THBS2 expression in a pan-cancer analysis and its association with pan-cancer prognosis and to further identify its possible roles in tumor immunity and the extracellular matrix (ECM).

Methods

Data on THBS2 expression in cancers and normal tissues were downloaded from the Genotype-Tissue Expression portal and UCSC Xena visual exploration tool and analyzed using the ONCOMINE database, Perl programming language, and Gene Expression Profiling and Interactive Analyses vision 2 webserver. In addition, survival prognosis was analyzed using the survival, survminer, limma, and forestplot packages in R v. 4.0.3.Immune and matrix components were also analyzed using R v. 4.0.3. Most importantly, we partially validated the role and mechanism of THBS2 in pancreatic and gastric cancers in vitro using PANC1 and BGC-823 cell lines.

Results

THBS2 was significantly overexpressed in 17 of the 33 investigated cancers and linked to a poor prognosis in pan-cancer survival analysis. High THBS2 expression was an independent unfavorable prognostic factor in kidney renal papillary cell, mesothelioma, and stomach and pancreatic adenocarcinomas. Immune infiltration and THBS2 expression were also related. THBS2 expression has been linked to immune and stromal scores and immune checkpoint markers in various cancers. The protein–protein interaction network revealed that THBS2 is associated with multiple ECM and immune proteins. THBS2 knockdown decreased the expression of CD47 and matrix metallopeptidase 2 (MMP-2) as well as the proliferation, migration, and invasion of PANC1 and BGC-823 cells in vitro.

Conclusions

Our findings suggested that THBS2 might promote cancer progression by remodeling the tumor microenvironment, affecting CD47-mediated signaling pathways, activating the pro-tumor functions of a disintegrin and metalloproteinase with thrombospondin motifs, and enhancing MMP-2 expression. Furthermore, it functions as a bridge between the ECM and immune infiltration in cancer and serves as a potential prognostic biomarker for several cancers, especially pancreatic and gastric adenocarcinomas.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12935-022-02622-x.