Investigating the immunological function of alpha-2-glycoprotein 1, zinc-binding in regulating tumor response in the breast cancer microenvironment.

BACKGROUND: Alpha-2-glycoprotein 1, zinc-binding (ZAG), a secreted protein encoded by the AZGP1 gene, is structurally similar to HLA class I. Despite its presumed immunological function, little is known about its role in tumor immunity. In this study, we thus aimed to determine the relationship between the expression of AZGP1/ZAG and the immunological profiles of breast cancer tissues at both the gene and protein level. METHODS: Using a publicly available gene expression dataset from a large-scale breast cancer cohort, we conducted gene set enrichment analysis (GSEA) to screen the biological processes associated with AZGP1. We analyzed the correlation between AZGP1 expression and immune cell composition in breast cancer tissues, estimated using CIBERSORTx. Previously, we evaluated the infiltration of 11 types of immune cells for 45 breast cancer tissues using flow cytometry (FCM). ZAG expression was evaluated by immunohistochemistry on these specimens and analyzed for its relationship with immune cell infiltration. The action of ZAG in M1/M2 polarization models using primary cultures of human peripheral blood mononuclear cells (PBMC)-derived macrophage (Mφ) was analyzed based on the expression of M1/M2 markers (CD86, CD80/CD163, MRC1) and HLA class I/II by FCM. RESULTS: AZGP1 expression was negatively correlated with multiple immunological processes and specific immune cell infiltration including Mφ M1 using GSEA and CIBERSORTx. ZAG expression was associated with decreased infiltration of monocytes/macrophages, non-classical monocytes, and myeloid-derived suppressor cells in tumor tissues assessed using FCM. In in vitro analyses, ZAG decreased the expression of CD80, CD163, MRC1, and HLA classes I/II in the M1 polarization model and the expression of CD163 and MRC1 in the M2 polarization model. CONCLUSION: ZAG is suggested to be a novel immunoregulatory factor affecting the Mφ phenotype in breast cancer tissues.

AZGP1 Up-Regulation is a Potential Target for Andrographolide Reversing Radioresistance of Colorectal Cancer.

Background: Radiation resistance is a challenge that limits the therapeutic benefit of colorectal cancer (CRC) treatment, but the mechanism underlying CRC radiation resistance remains unclear. Andrographolide shows a broad-spectrum anti-tumor effect in various malignancies, including CRC, its effect and how it functions in CRC initiation, and radiation have not been established. This study aimed to explore the mechanism of CRC radiation resistance and the potential mechanisms of andrographolide on CRC radiation. Methods: Two acquired radioresistant cell lines were established and high throughput sequencing was employed to screen out the differentially expressed genes. The expression of AZGP1, which was upregulated in the acquired radioresistant tissues, was verified by microarray data recomputing. The common targets of andrographolide, CRC initiation, and radiation resistance were obtained, and the corresponding functional enrichment and pathway analysis were performed. The interaction between AZGP1 and andrographolide was investigated using molecular docking. Results: AZGP1 was upregulated in both the radioresistant cell model and microarray data. Moreover, AZGP1 was upregulated in cancerous colorectal tissue and displayed a tendency toward elevated expression in patients with an unfavorable prognosis. AZGP1 was identified as the common target of andrographolide, colorectal cancer initiation, and radiotherapy resistance. Ultimately, the protein structure of AZGP1 proved to be closely intertwined with the crystal texture of andrographolide. Conclusion: AZGP1 is recognized as a crucial factor for both CRC initiation and radioresistance. Andrographolide may affect the radioresistance of CRC via the targeting of AZGP1. Thus, the combination of andrographolide and AZGP1 intervention might be a promising strategy for improving the treatment benefit of CRC radiotherapy.