Background: Neutrophils can play a pro-tumor or anti-tumor role depending on the tumor microenvironment. The effects of concurrent treatment with granulocyte colony-stimulating factor (G-CSF) and radiotherapy (RT) on neutrophils have not yet to be described.Methods: Hypofractionated radiation of 8 Gy ×3 fractions was administered with or without recombinant G-CSF to Lewis lung carcinoma tumor-bearing C57BL/6 model mice. The activation status of cytotoxic T cells in the mice was measured, along with the levels of tumor-associated neutrophils, cytotoxic T cells, and Treg cells. Tumor growth, survival, cytokine expression, and signaling pathways underlying antitumor effects of tumor-associated neutrophils after treatment were also studied. To ascertain the effects of concurrent RT and G-CSF on tumor-associated neutrophils, neutrophil depletion was performed.Results: RT affected early neutrophil infiltration, which is the first-line immune response. Subsequently, enhanced accumulation of lymphocytes, particularly CD8 cytotoxic T cells, was observed. Notably, lymphocytic infiltration was inhibited by neutrophil depletion but enhanced by G-CSF treatment. RT generated persistent DNA damage, as evidenced by an accumulation of phosphorylation of histone H2AX (γH2AX), and subsequently triggered inflammatory chemokine secretion. The chemokines CXCL1, CXCL2, and CCL5 were upregulated in both radiation-treated cells and the corresponding supernatants. Neutrophils that were newly recruited after RT improved radiosensitivity by inhibiting epithelial-mesenchymal transition via the reactive oxygen species-mediated PI3K/Akt/Snail signaling pathway, and G-CSF treatment enhanced this effect. Conclusions:The results of this study suggest that RT activates neutrophil recruitment and polarizes newly recruited neutrophils toward an antitumor phenotype, which is enhanced by the concurrent administration of G-CSF. Mesenchymal-epithelial transition induced by reactive oxygen species accumulation plays a major role in this process. Thus, the polarization of tumor-associated neutrophils might play a role in future cancer immunotherapies.

Background: Radiation-induced lung injury (RILI) is a common complication of thoracic cancer radiation therapy. Currently, there is no effective treatment for RILI. RILI is associated with chronic inflammation, this injury is perpetuated by the stimulation of chemokines and proinflammatory cytokines. Recent studies have demonstrated that granulocyte-macrophage colony-stimulating factor (GM-CSF) plays a pivotal role in inflammation and fibrosis. This study aimed to investigate the protective effect of GM-CSF against the development of RILI in lung tissue.Method: First, a single fraction of radiation at a dose of 16 Gy was targeted at the entire thorax of wild-type (WT) C57BL/6 mice and GM-CSF -/mice to induce RILI. Second, we detected the radioprotective effects of GM-CSF by measuring the inflammatory biomarkers and fibrosis alteration on radiated lung tissues. Furthermore, we investigated the potential mechanism of GM-CSF protective effects in RILI. Results:The GM-CSF -/mice sustained more severe RILI than the WT mice. RILI was significantly alleviated by GM-CSF treatment. Intraperitoneally administered GM-CSF significantly inhibited inflammatory cytokine production and decreased epithelial-mesenchymal transition (EMT) in the RILI mouse model. Conclusions: GM-CSF was shown to be an important modulator of RILI through regulating inflammatory cytokines, which provides a new strategy for the prevention and treatment of RILI.

Background: Tumor-associated neutrophils (TANs) have been a research hotspot in recent years.However, the role and relevant mechanisms of TANs in the tumor microenvironment (TME) have not yet been elucidated. Method: The ribonucleic acid (RNA) expression levels of fucosyltransferase 4 (FUT4) and elastase, neutrophil expressed (ELANE) in samples from The Cancer Genome Atlas (TCGA) (n=4,538) were analyzed. Receiver operating characteristic (ROC) curves were used to calculate the critical cutoff values, and different data were defined as high and low expression. The tumor microenvironment immune type (TMIT) was defined according to the activation state of TAN, and the samples were classified into three TMITs based on their cut-off values. Mutational datasets and overall survival were compared according to the TMITs. Results: The prognostic significance of FUT4, ELANE, and myeloperoxidase (MPO) was different among the 15 cancers, and the prognostic significance of different TMITs varied across the different tumors. Compared with the other groups, TMIT 3 had a favorable prognostic effect, which was most prominent in lung adenocarcinoma (LUAD) [hazard ratio (HR) =0.292, 95% confidence interval (CI): 0.185-0.459, P<0.001].Conclusions: Our study demonstrated that highly-activated TANs predicted a favorable prognosis in humans using genomic analyses for the first time. This provides a realistic basis for further exploring the role of TANs in the immune microenvironment and provides real world data for tumor immunotherapy.

Background: The prognostic role and underlying heterogeneity of negative lymph nodes (NLNs) on colon cancer is not well understood. The purpose of this study was to construct NLN-based prognostic models and reveal relevant mechanisms affecting NLNs by analyzing omic data.Methods: This inception cohort study included 314,398 colon cancer patients from the US Surveillance, Epidemiology, and End Results (SEER) database. Receiver operating characteristic (ROC) curve was used to determine the cut-off of NLNs. Nomograms were constructed and validated using SEER data and the Cancer Genome Atlas (TCGA) data, respectively. The differentially expressed genes (DEGs) were analyzed using edgeR. Enrichment analyses were performed by Metascape.Results: Multivariate analysis confirmed the high NLN had improved cancer-specific survival (CSS) and overall survival (OS) compared to low NLN [hazard ratio (HR) =0.610, 95% confidence interval (CI), 0.601-0.620] for CSS and (HR =0. 682, 95% CI, 0.674-0.690) for OS. Nomograms were established for CSS and OS with the c-statistic 0.790 (95% CI, 0.788-0.792) for CSS and 0.734 (95% CI, 0.732-0.736) for OS. High NLN was associated with less B cell (P=0.002) and macrophage infiltration (P<0.0001), high microsatellite instability (MSI) (OR =4.325, P=0.001), and hypermutation (OR =4.285, P=0.001; high vs. low). Transcriptomics analysis demonstrated histone modifiers were the most significant different biological processes between the high and low NLN group. Conclusions:The NLN-based models can aid in personalized risk stratification for colon cancer. This study postulates that high NLN may represent a biological subtype with less macrophage infiltration, high MSI status, hypermutation, and histone modifier gene enriched expression, and thus warrants further investigation.