Identification of lysine acetylome of oral squamous cell carcinoma by label-free quantitative proteomics

Lactylome analyses suggest systematic lysine-lactylated substrates in oral squamous cell carcinoma under normoxia and hypoxia

Cancer cells tend to live in hypoxic environment characterized by enhanced glycolysis and accumulation of lactate. Intracellular lactate is shown to drive a novel type of post-translational modification (PTM), lysine lactylation (Kla). Kla has been confirmed to affect the malignant progression of tumors such as hepatocellular carcinoma (HCC) and colon cancer, whereas the global lactylomic profiling of oral squamous cell carcinoma (OSCC) is unclear. Here, the integrative lactylome and proteome analyses by using liquid chromatography-tandem mass spectrometry (LC-MS/MS) identified 1011 Kla sites within 532 proteins and 1197 Kla sites within 608 proteins in SCC25 cells under normoxic and hypoxic environments, respectively. Among these lactylated proteins, histones accounted for only a small fraction, suggesting the presence of Kla modification of OSCC in a large number of non-histone proteins. Notably, Kla preferred to enrich in spliceosome, ribosome and glycolysis/gluconeogenesis pathway in both normoxic and hypoxic cultures. Compared with normoxia, 589 differential proteins with 898 differentially lactylated sites were detected under hypoxia, which were mainly associated with the glycolysis/gluconeogenesis pathway by KEGG analysis. Importantly, we verified the presence of lactylation modification in the spliceosomal proteins hnRNPA1, SF3A1, hnRNPU and SLU7, as well as in glycolytic enzyme PFKP. In addition, the differential alternative splicing analysis described the divergence of pre-mRNA splicing patterns in the presence or absence of sodium lactate and at different oxygen concentrations. Finally, a negative correlation between tissue Kla levels and the prognosis of OSCC patients was revealed by immunohistochemistry. Our study is the first report to elucidate the lactylome and its biological function in OSCC, which deepens our understanding of the mechanisms underlying OSCC progression and provides a novel strategy for targeted therapy for OSCC.

Identification of histone acetylation modification sites in the striatum of subchronically manganese-exposed rats

Aim: To explore the specific histone acetylation sites and oxidative stress-related genes that are associated with the pathogenesis of manganese toxicity. Methods: We employed liquid chromatography-tandem mass spectrometry and bioinformatics analysis to identify acetylated proteins in the striatum of subchronic manganese-intoxicated rats. Results: We identified a total of 12 differentially modified histone acetylation sites: H3K9ac, H3K14ac, H3K18ac, H3K56ac and H3K79ac were upregulated and H3K27ac, H3K36ac, H4K91ac, H4K79ac, H4K31ac, H2BK16ac and H2BK20ac were downregulated. Additionally, we found that CAT, SOD1 and SOD2 might be epigenetically regulated and involved in the pathogenesis of manganism. Conclusion: This study identified histone acetylation sites and oxidative stress-related genes associated with the pathogenesis of manganese toxicity, and these findings are useful in the search for potential epigenetic targets for manganese toxicity.

Prognostic evaluation of oral squamous cell carcinoma based on pleiotrophin, urokinase plasminogen activator, and glycoprotein nonmetastatic melanoma protein B expression

This study investigated the expression of pleiotrophin (PTN), urokinase plasminogen activator (uPA), and glycoprotein nonmetastatic melanoma protein B (GPNMB) in oral squamous cell carcinoma (OSCC) tissues and their correlation with prognosis. From February 2017 to January 2020, PTN, uPA, and GPNMB expression in cancer tissues and adjacent tissues of 93 patients with OSCC was determined using immunohistochemistry. The diagnostic value of the combined detection of OSCC and its relationship with clinicopathological characteristics were analyzed, as well as the prognostic potential of PTN, uPA, and GPNMB. Cancer tissues from patients with OSCC exhibited high expression of PTN, uPA, and GPNMB. The AUC for the combined detection of PTN, uPA, and GPNMB for diagnosis and prognosis was greater than that of each index alone. The rates of expression of PTN, uPA, and GPNMB were higher in the death group than in the survival group. Patients with PTN, uPA, and GPNMB expression had lower 3-year survival rates. PTN expression was a risk factor affecting the prognosis of patients with OSCC. The rate of PTN, uPA, and GPNMB expression in OSCC tissues was high, and their expression was related to clinicopathological features such as lymph node metastasis and tumor invasion depth. The combined detection of each index has a predictive value for the prognosis of patients.

Integrative analysis of lysine acetylation-related genes and identification of a novel prognostic model for oral squamous cell carcinoma

Introduction: Oral squamous cell carcinoma (OSCC), which accounts for a high proportion of oral cancers, is characterized by high aggressiveness and rising incidence. Lysine acetylation is associated with cancer pathogenesis. Lysine acetylation-related genes (LARGs) are therapeutic targets and potential prognostic indicators in various tumors, including oral squamous cell carcinoma. However, systematic bioinformatics analysis of the Lysine acetylation-related genes in Oral squamous cell carcinoma is still unexplored. Methods: We analyzed the expression of 33 Lysine acetylation-related genes in oral squamous cell carcinoma and the effects of their somatic mutations on oral squamous cell carcinoma prognosis. Consistent clustering analysis identified two lysine acetylation patterns and the differences between the two patterns were further evaluated. Least absolute shrinkage and selection operator (LASSO) regression analysis was used to develop a lysine acetylation-related prognostic model using TCGA oral squamous cell carcinoma datasets, which was then validated using gene expression omnibus (GEO) dataset GSE41613. Results: Patients with lower risk scores had better prognoses, in both the overall cohort and within the subgroups These patients also had "hot" immune microenvironments and were more sensitive to immunotherapy. Disscussion: Our findings offer a new model for classifying oral squamous cell carcinoma and determining its prognosis and offer novel insights into oral squamous cell carcinoma diagnosis and treatment.

ELFN1-AS1 promotes GDF15-mediated immune escape of colorectal cancer from NK cells by facilitating GCN5 and SND1 association

The ability of colorectal cancer (CRC) cells to escape from natural killer (NK) cell immune surveillance leads to anti-tumor treatment failure. The long non-coding RNA (lncRNA) ELFN1-AS1 is aberrantly expressed in multiple tumors suggesting a role as an oncogene in cancer development. However, whether ELFN1-AS1 regulates immune surveillance in CRC is unclear. Here, we determined that ELFN1-AS1 enhanced the ability of CRC cells to escape from NK cell surveillance in vitro and in vivo. In addition, we confirmed that ELFN1-AS1 in CRC cells attenuated the activity of NK cell by down-regulating NKG2D and GZMB via the GDF15/JNK pathway. Furthermore, mechanistic investigations demonstrated that ELFN1-AS1 enhanced the interaction between the GCN5 and SND1 protein and this influenced H3k9ac enrichment at the GDF15 promotor to stimulate GDF15 production in CRC cells. Taken together, our findings indicate that ELFN1-AS1 in CRC cells suppresses NK cell cytotoxicity and ELFN1-AS1 is a potential therapeutic target for CRC.