Downregulation of Ubiquitin Inhibits the Aggressive Phenotypes of Esophageal Squamous Cell Carcinoma

Interferon regulatory factor 1‐triggered free ubiquitin protects the intestines against radiation‐induced injury via CXCR4/FGF2 signaling

Radiation‐induced intestinal injury is a serious concern during abdominal and pelvic cancers radiotherapy. Ubiquitin (Ub) is a highly conserved protein found in all eukaryotic cells. This study aims to explore the role and mechanism of free Ub against radiogenic intestinal injury. We found that free Ub levels of irradiated animals and human patients receiving radiotherapy were upregulated. Radiation‐induced Ub expression was associated with the activation of interferon regulatory factor 1 (IRF1). Intraperitoneal injection of free Ub significantly reduced the mortality of mice following 5–9 Gy total body irradiation (TBI) through the Akt pathway. Free Ub facilitates small intestinal regeneration induced by TBI or abdominal irradiation. At the cellular level, free Ub or its mutants significantly alleviated cell death and enhanced the survival of irradiated intestinal epithelial cells. The radioprotective role of free Ub depends on its receptor CXCR4. Mechanistically, free Ub increased fibroblast growth factor‐2 (FGF2) secretion and consequently activated FGFR1 signaling following radiation in vivo and in vivo. Thus, free Ub confers protection against radiation‐induced intestinal injury through CXCR4/Akt/FGF2 axis, which provides a novel therapeutic option.

SYNGR2 serves as a prognostic biomarker and correlates with immune infiltrates in esophageal squamous cell carcinoma

BACKGROUND

Synaptogyrin-2 (SYNGR2) plays an important role in regulating membrane traffic in nonneuronal cells. However, the role of SYNGR2 in esophageal squamous cell carcinoma (ESCC) remains unclear.

METHODS

All original data were downloaded from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) databases and integrated via R 3.5.3. SYNGR2 expression was explored in the TCGA and GEO databases. The correlations between SYNGR2 and cancer immune characteristics were analyzed via the TIMER and TISIDB databases.

RESULTS

In general, SYNGR2 was predominantly overexpressed and had reference value in the diagnosis and prognostic estimation of ESCC. Upregulated SYNGR2 was associated with poorer overall survival, poorer disease-specific survival and T stage in ESCC. Mechanistically, we identified hub genes that included a total of 38 SYNGR2-related genes, which were tightly associated with the protein polyubiquitination pathway in ESCC patients. SYNGR2 expression was negatively related to the infiltrating levels of T helper cells. SYNGR2 methylation was positively correlated with the expression of chemokines (CCL2 and CXCL12), chemokine receptors (CCR1 and CCR2), immunoinhibitors (CXCL12 and TNFRSF4) and immunostimulators (CSF1R and PDCD1LG2) in ESCC.

CONCLUSION

SYNGR2 may be used as a biomarker for determining prognosis and immune infiltration in ESCC.

Iron Metabolism in the Tumor Microenvironment-Implications for Anti-Cancer Immune Response

New insights into the field of iron metabolism within the tumor microenvironment have been uncovered in recent years. Iron promotes the production of reactive oxygen species, which may either trigger ferroptosis cell death or contribute to malignant transformation. Once transformed, cancer cells divert tumor-infiltrating immune cells to satisfy their iron demand, thus affecting the tumor immunosurveillance. In this review, we highlight how the bioavailability of this metal shapes complex metabolic pathways within the tumor microenvironment and how this affects both tumor-associated macrophages and tumor-infiltrating lymphocytes functions. Furthermore, we discuss the potentials as well as the current clinical controversies surrounding the use of iron metabolism as a target for new anticancer treatments in two opposed conditions: i) the "hot" tumors, which are usually enriched in immune cells infiltration and are extremely rich in iron availability within the microenvironment, and ii) the "cold" tumors, which are often very poor in immune cells, mainly due to immune exclusion.