Despite extensive research, the molecular role of AGR2 in the progression and metastasis of colorectal cancer (CRC) has not been fully characterized. We used quantitative mass spectrometry (SWATH MS) to identify differentially expressed proteins in paired CRC cell models of the SW480 and SW620 cell lines in response to AGR2 protein level manipulation. Relying on the results from SWATH MS and subsequent immunochemical validation, we selected NMP3 as the top candidate protein associated with AGR2 in CRC tumour cells in our screen. RT‒qPCR and immunochemical analysis confirmed the involvement of AGR2-mediated regulation of NPM3 at the transcriptional and posttranscriptional levels. Since PD-L1 is a constituent of the NPM3 regulatory axis, we aimed to correlate the changes in PD-L1 to the differential expression of AGR2 in our cell models. We found that AGR2 positively regulates PD-L1 levels in both SW480 and SW620 cell lines; additionally, several different CRC patient transcriptome cohorts confirmed the association of AGR2 with PD-L1. Our work reveals a new AGR2-NPM3 regulatory axis and the involvement of AGR2 in the regulation of PD-L1, which paves the way for the association of AGR2 with immune evasion in CRC cells.

• Klíčová slova
• AGR2, Colorectal cancer, NPM3, PD-L1,
• MeSH
• antigeny CD274 * metabolismus   genetika   MeSH
• jaderné proteiny metabolismus   genetika   MeSH
• kolorektální nádory * genetika   metabolismus   patologie   MeSH
• lidé MeSH
• mukoproteiny * metabolismus   genetika   MeSH
• nádorové buněčné linie MeSH
• nukleofosmin * MeSH
• onkogenní proteiny * metabolismus   genetika   MeSH
• proteiny * metabolismus   genetika   MeSH
• regulace genové exprese u nádorů * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• AGR2 protein, human MeSH Prohlížeč
• antigeny CD274 * MeSH
• CD274 protein, human MeSH Prohlížeč
• jaderné proteiny MeSH
• mukoproteiny * MeSH
• NPM3 protein, human MeSH Prohlížeč
• nukleofosmin * MeSH
• onkogenní proteiny * MeSH
• proteiny * MeSH

The TGF-β signaling pathway is involved in numerous cellular processes, and its deregulation may result in cancer development. One of the key processes in tumor progression and metastasis is epithelial to mesenchymal transition (EMT), in which TGF-β signaling plays important roles. Recently, AGR2 was identified as a crucial component of the cellular machinery responsible for maintaining the epithelial phenotype, thereby interfering with the induction of mesenchymal phenotype cells by TGF-β effects in cancer. Here, we performed transcriptomic profiling of A549 lung cancer cells with CRISPR-Cas9 mediated AGR2 knockout with and without TGF-β treatment. We identified significant changes in transcripts associated with focal adhesion and eicosanoid production, in particular arachidonic acid metabolism. Changes in transcripts associated with the focal adhesion pathway were validated by RT-qPCR of COL4A1, COL4A2, FLNA, VAV3, VEGFA, and VINC mRNAs. In addition, immunofluorescence showed the formation of stress fibers and vinculin foci in cells without AGR2 and in response to TGF-β treatment, with synergistic effects observed. These findings imply that both AGR2 downregulation and TGF-β have a role in focal adhesion formation and cancer cell migration and invasion. Transcripts associated with arachidonic acid metabolism were downregulated after both AGR2 knockout and TGF-β treatment and were validated by RT-qPCR of GPX2, PTGS2, and PLA2G4A. Since PGE2 is a product of arachidonic acid metabolism, its lowered concentration in media from AGR2-knockout cells was confirmed by ELISA. Together, our results demonstrate that AGR2 downregulation and TGF-β have an essential role in focal adhesion formation; moreover, we have identified AGR2 as an important component of the arachidonic acid metabolic pathway.

• Klíčová slova
• AGR2, EMT, RNAseq, TGF-β, arachidonic acid, focal adhesion,
• MeSH
• cyklooxygenasa 2 genetika   MeSH
• epitelo-mezenchymální tranzice * genetika   MeSH
• kyselina arachidonová MeSH
• nádorové buněčné linie MeSH
• pohyb buněk genetika   MeSH
• prostaglandiny E MeSH
• regulace genové exprese u nádorů * MeSH
• transformující růstový faktor beta genetika   MeSH
• vinkulin genetika   MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• cyklooxygenasa 2 MeSH
• kyselina arachidonová MeSH
• prostaglandiny E MeSH
• transformující růstový faktor beta MeSH
• vinkulin MeSH

Anterior gradient 2 (AGR2) is an endoplasmic reticulum (ER)-resident protein disulfide isomerase (PDI) known to be overexpressed in many human epithelial cancers and is involved in cell migration, cellular transformation, angiogenesis, and metastasis. This protein inhibits the activity of the tumor suppressor p53, and its expression levels can be used to predict cancer patient outcome. However, the precise network of AGR2-interacting partners and clients remains to be fully characterized. Herein, we used label-free quantification and also stable isotope labeling with amino acids in cell culture-based LC-MS/MS analyses to identify proteins interacting with AGR2. Functional annotation confirmed that AGR2 and its interaction partners are associated with processes in the ER that maintain intracellular metabolic homeostasis and participate in the unfolded protein response, including those associated with changes in cellular metabolism, energy, and redox states in response to ER stress. As a proof of concept, the interaction between AGR2 and PDIA3, another ER-resident PDI, was studied in more detail. Pathway analysis revealed that AGR2 and PDIA3 play roles in protein folding in ER, including post-translational modification and in cellular response to stress. We confirmed the AGR2-PDIA3 complex formation in cancer cells, which was enhanced in response to ER stress. Accordingly, molecular docking characterized potential quaternary structure of this complex; however, it remains to be elucidated whether AGR2 rather contributes to PDIA3 maturation in ER, the complex directly acts in cellular signaling, or mediates AGR2 secretion. Our study provides a comprehensive insight into the protein-protein interaction network of AGR2 by identifying functionally relevant proteins and related cellular and biochemical pathways associated with the role of AGR2 in cancer cells.

• Klíčová slova
• anterior gradient protein 2, mass spectrometry, protein disulfide isomerase, protein–protein interactions, secretory pathway,
• MeSH
• chromatografie kapalinová MeSH
• lidé MeSH
• mapy interakcí proteinů MeSH
• mukoproteiny * metabolismus   MeSH
• nádory * MeSH
• onkogenní proteiny * metabolismus   MeSH
• proteindisulfidisomerasy * MeSH
• simulace molekulového dockingu MeSH
• tandemová hmotnostní spektrometrie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• AGR2 protein, human MeSH Prohlížeč
• mukoproteiny * MeSH
• onkogenní proteiny * MeSH
• proteindisulfidisomerasy * MeSH