PD-1 Carried on Small Extracellular Vesicles Leads to OSCC Metastasis.

Immune checkpoint molecule PD-1, expressed on the cell surface, impairs antigen-driven activation of T cells and thus plays a critical role in tumorigenesis, progression, and the poor prognosis of oral squamous cell carcinoma (OSCC). In addition, increasing evidence indicates that PD-1 carried on small extracellular vesicles (sEVs) also mediates tumor immunity, although their contributions to OSCC are yet unclear. Here, we investigated the biological functions of sEV PD-1 in patients with OSCC. The cell cycle, proliferation, apoptosis, migration, and invasion of CAL27 cell lines treated with or without sEV PD-1 were examined in vitro. We performed mass spectrometry to investigate the underlying biological process, combined with an immunohistochemical study of SCC7-bearing mice models and OSCC patient samples. In vitro data demonstrated that sEV PD-1 induced senescence and subsequent epithelial-mesenchymal transition (EMT) in CAL27 cells by ligating with tumor cell surface PD-L1 and activating the p38 mitogen-activated protein kinase (MAPK) pathway. Comprehensive immunohistochemical analysis of the xenograft mice models and OSCC patient samples revealed a very close correlation between the level of circulating sEV PD-1 and lymph node metastasis. These results demonstrate that circulating sEV PD-1 triggers senescence-initiated EMT in a PD-L1-p38 MAPK-dependent manner, contributing to tumor metastasis. It also suggests that the inhibition of sEV PD-1 may be a promising therapeutic target for the treatment of OSCC.

[Analysis of the characteristics of retracted scientific papers in the field of global liver diseases published by Chinese scholars].

Objective: To analyze the characteristics of scientific papers in the field of global liver diseases published by Chinese scholars that were retracted for diverse reasons from the Retraction Watch database, so as to provide a reference to publishing-related papers. Methods: The Retraction Watch database was retrieved for retracted papers in the field of global liver disease published by Chinese scholars from March 1, 2008 to January 28, 2021. The regional distribution, source journals, reasons for retraction, publication and retraction times, and others were analyzed. Results: A total of 101 retracted papers that were distributed across 21 provinces/cities were retrieved. Zhejiang area (n = 17) had the most retracted papers, followed by Shanghai (n = 14), and Beijing (n = 11). The vast majority were research papers (n = 95). The journal PLoS One had the highest number of retracted papers. In terms of time distribution, 2019 (n = 36) had the most retracted papers. 23 papers, accounting for 8.3% of all retractions, were retracted owing to journal or publisher concerns. Liver cancer (34%), liver transplantation (16%), hepatitis (14%), and others were the main areas of retracted papers. Conclusion: Chinese scholars have a large number of retracted articles in the field of global liver diseases. A journal or publisher chooses to retract a manuscript after investigating and discovering more flawed problems, which, however, require further support, revision, and supervision from the editorial and academic circles.

KGF Enhances Oral Epithelial Adhesion and Rete Peg Elongation via Integrins.

Oral epithelial adhesion to the lamina propria underlies the physiologic function of the oral mucosa and contributes to resisting bacterial invasion, preventing body fluid loss, and maintaining routine chewing; thus, understanding the factors that positively influence oral epithelial adhesion is a research topic of great interest. Rete pegs contribute to oral epithelial adhesion by enlarging the contact areas, whereas integrins are the major molecules that mediate epithelial cell adhesion to the basement membrane. Keratinocyte growth factor (KGF) can promote both rete peg elongation in the skin and the expression of integrins in various cell types. Herein, we tested the effects of submucosal injection of KGF in the ventral surfaces of rat tongues on oral epithelial adhesion. The data confirmed that topical injection of KGF elevated the adhesive forces, elongated the rete pegs, and increased the abundance of integrins, KGF, and KGF receptor on the rat tongue ventral surface. However, HYD-1 (Lys-Ile-Lys-Met-Val-Ile-Ser-Trp-Lys-Gly), an integrin antagonist, inhibited the KGF-enhanced epithelial adhesion and rete peg elongation. Moreover, KGF promoted the expression of integrin subunits α6, ß4, α3, and ß1 in human immortalized oral epithelial cells in 2- and 3-dimensional culture systems. In vitro cell attachment assays demonstrated that HYD-1 inhibited the adhesion of human immortalized oral epithelial cells on Matrigel. Strikingly, the expression of integrins, KGF, and KGFR in human masticatory mucosae with longer rete pegs was more abundant than that in the lining mucosae with shorter rete pegs. In addition, rete peg lengths were positively correlated with the expression levels of integrins, KGF, and KGF receptor. These findings indicate that KGF strengthens oral epithelial adhesion and rete peg elongation via integrins.