Shu Hong, Zhang Lei, Chen Yiwei, Guo Yijie, Li Limin, Chen Fanghua, Cao Zhao, Yan Guoquan, Lu Chunlai, Liu Chao, Zhang Shu
Liver Cancer Institute, Zhongshan Hospital, and Key Laboratory of Carcinogenesis and Cancer Invasion (Ministry of Education), Fudan University, Shanghai, China.
Department of Clinical Laboratory, Cancer Hospital of Guangxi Medical University, Nanning, China.
Front Chem. 2021 Jul 14;9:705341. doi: 10.3389/fchem.2021.705341. eCollection 2021.
Haptoglobin (Hp) is one of the acute-phase response proteins secreted by the liver, and its aberrant N-glycosylation was previously reported in hepatocellular carcinoma (HCC). Limited studies on Hp O-glycosylation have been previously reported. In this study, we aimed to discover and confirm its O-glycosylation in HCC based on lectin binding and mass spectrometry (MS) detection. First, serum Hp was purified from patients with liver cirrhosis (LC) and HCC, respectively. Then, five lectins with Gal or GalNAc monosaccharide specificity were chosen to perform lectin blot, and the results showed that Hp in HCC bound to these lectins in a much stronger manner than that in LC. Furthermore, label-free quantification based on MS was performed. A total of 26 intact O-glycopeptides were identified on Hp, and most of them were elevated in HCC as compared to LC. Among them, the intensity of HYEGS TVPEK (H1N1S1) on Hp was the highest in HCC patients. Increased HYEGS TVPEK (H1N1S1) in HCC was quantified and confirmed using the MS method based on O/O C-terminal labeling and multiple reaction monitoring. This study provided a comprehensive understanding of the glycosylation of Hp in liver diseases.
触珠蛋白（Hp）是肝脏分泌的急性期反应蛋白之一，此前有报道称其在肝细胞癌（HCC）中存在异常的N-糖基化。此前关于Hp O-糖基化的研究较少。在本研究中，我们旨在基于凝集素结合和质谱（MS）检测来发现并确认其在HCC中的O-糖基化。首先，分别从肝硬化（LC）患者和HCC患者中纯化血清Hp。然后，选择五种对Gal或GalNAc单糖具有特异性的凝集素进行凝集素印迹分析，结果显示HCC中的Hp与这些凝集素的结合比LC中的更强。此外，基于MS进行了无标记定量分析。在Hp上共鉴定出26个完整的O-糖肽，与LC相比，其中大多数在HCC中升高。其中，Hp上的HYEGS TVPEK（H1N1S1）在HCC患者中的强度最高。使用基于O/O C末端标记和多反应监测的MS方法对HCC中增加的HYEGS TVPEK（H1N1S1）进行了定量和确认。本研究全面了解了肝脏疾病中Hp的糖基化情况。
