Hydrophilic magnetic covalent triazine frameworks for differential N-glycopeptides enrichment in breast cancer plasma membranes

The dual role of SUSD2 in cancer development

Sushi domain-containing protein 2 (SUSD2, also known as the complement control protein domain) is a representative and vital protein in the SUSD protein family involved in many physiological and pathological processes beyond complement regulation. Cancer is one of the leading causes of death worldwide. The complex role of SUSD2 in tumorigenesis and cancer progression has raised increasing concerns. Studies suggest that SUSD2 has different regulatory tendencies among different tumors and exerts its biological effects in a cancer type-specific manner; for instance, it has oncogenic effects on breast cancer, gastric cancer, and glioma and has tumor-suppression effects on lung cancer, bladder cancer, and colon cancer. Moreover, SUSD2 can be regulated by noncoding RNAs, its promoter methylation and other molecules, such as Galectin-1 (Gal-1), tropomyosin alpha-4 chain (TPM4), and p63. The therapeutic implications of targeting SUSD2 have already been preliminarily revealed in some malignancies, including melanoma, colon cancer, and breast cancer. This article reviews the role and regulatory mechanisms of SUSD2 in cancer development, as well as its structure and distribution. We hope that this review will advance the understanding of SUSD2 as a diagnostic and/or prognostic biomarker and provide new avenues for the development of novel cancer therapies.

Hydrophilic glutathione-modified flower-like hollow covalent organic frameworks for highly efficient capture of N-linked glycopeptides

Highly efficient enrichment of N-glycopeptides from complicated biosamples based on mass spectrometry is essential for biomedical applications, especially in disease biomarker research. In this work, glutathione (GSH)-modified hierarchical flower-like hollow covalent organic frameworks loaded with Au nanoparticles (HFH-COFs@Au@GSH) were synthesized for N-glycopeptide enrichment. Due to the abundant accessibility sites, high specific surface area, and inherent high stability of the hierarchical flower-like hollow structure, a large number of Au NPs and hydrophilic GSH can be modified on the HFH-COFs. The HFH-COFs@Au@GSH displayed excellent hydrophilicity and remarkable enrichment performance for N-glycopeptides: low detection limit (0.1 fmol μL^-1), large adsorption capacity (200 μg mg^-1), great selectivity (1 : 1000, HRP to BSA), and good reusability (at least 5 times). Furthermore, the HFH-COFs@Au@GSH were successfully applied to capture N-linked glycopeptides in human serum, and 308 N-glycosylation peptides corresponding to 84 N-glycosylation proteins with 123 N-glycosylation sites were detected. Gene ontology analyses were used to elucidate the cellular component, biological process and molecular function of detected glycoproteins in human serum, demonstrating the great potential of the HFH-COFs@Au@GSH in N-glycopeptide enrichment for glycoproteomic analysis of complex biological samples.