Autophagy-Related Gene CXCR4 is a Potential Predictor of Prognosis and Immunotherapy Response for Gastric Cancer.

BACKGROUND: Autophagy is involved in the survival, differentiation, and activation of immune cell subsets. In this study, we determined the prognostic value and biological functions of autophagy genes in gastric cancer (GC). METHODS: The RNA sequencing dataset for gastric cancer was obtained. Differences in prognosis and enrichment pathways in non-negative matrix factorization (NMF) subclasses were analyzed. Next, we analyzed CXC chemokine receptor 4 (CXCR4) by differential expression, clinical value, immune effects, tumor mutation burden (TMB) values, somatic variants, and biological functions. RESULTS: NMF identified three subclasses. Among the three subclasses, there were differences in prognosis, immune cell infiltration, immune checkpoint genes, and enrichment pathways. Moreover, CXCR4 level was elevated in most tumors, and high CXCR4 level was related to poor prognosis in GC patients. CXCR4 expression was significantly correlated with B cells, eosinophils, macrophages, and plasma cells. In in vitro experiment, CXCR4 promoted GC cell proliferation. CONCLUSIONS: Our results showed that CXCR4 is a promising biomarker for predicting prognosis and response to immunotherapy in GC.

Specificity and application of SOX2 antibody.

Sox2 is known to play an important role in maintaining the totipotency and self-renewal of embryonic stem cells. The purpose of this study was to prepare an anti-chicken Sox2 polyclonal antibody using prokaryotic expression techniques, to evaluate its specificity and to use it to investigate the expression and distribution of Sox2 in the chicken brain and lungs. The chicken Sox2 gene was amplified and subcloned to a pET-30a vector to construct a prokaryotic expression vector, pET-Sox2. A His-Sox2 fusion protein was expressed, purified, and used to prepare an antichicken Sox2 polyclonal antibody. Western blotting revealed that the antichicken Sox2 antibody could specifically bind not only to the purified His-Sox2 fusion protein but also to the endogenous Sox2 protein in the testes of chicken, showing a distinct dose-dependent relationship between antigen and Sox2 antibody. Indirect immunofluorescent staining of Sox2-overexpressing cells showed strong nuclear and diffuse cytoplasmic immunoreactivity for Sox2 in the antichicken Sox2 antibody-staining cells. A CRISPR/Cas9 effector system-mediated Sox2 knockdown assay indicated that Sox2 expression in HEK 293T cells was downregulated in the presence of doxycycline but upregulated in the absence of doxycycline. In addition, cryosectioning and immunohistochemical staining illustrated that most spermatogonia in the seminiferous tubules, and a small number of Sertoli and Leydig cells, were positive for Sox2. The antichicken Sox2 antibody was also successfully used to investigate the expression and distribution of Sox2 in the chicken cerebellar cortex, optic tectum, cerebral cortex, and lungs. The results of this study confirmed the specificity of the antichicken Sox2 polyclonal antibody, which will be available for the study of biological functions of the chicken Sox2 gene and the self-renewal mechanisms of chicken pluripotent stem cells.