RESUMO
BACKGROUND: Primary tracheobronchial neoplasm is rare yet poses a serious threat to life. Due to its low incidence, the immune microenvironment of such tumors remained unclear. This study aimed to clarify the expression of programmed death-ligand 1 (PD-L1) and infiltration of immune cells in primary tracheobronchial neoplasm, which might be useful for guiding treatment and evaluating clinical outcome. METHODS: We assessed retrospectively the expression of PD-L1 and infiltration in cells expressing CD8, CD16, CD68, CD163 and FOXP3 in 21 patients with primary tracheobronchial neoplasm who underwent surgery in Tangdu Hospital from January 2016 to July 2021. The expression of PD-L1 was assessed based on the tumor proportion score system. The density of immune cells was analyzed by automatic image analysis software. RESULTS: In this study, all of 16 participants with adenoid cystic carcinoma (ACC) had no expression of PD-L1, whereas 4/5 (80%) of those with squamous cell carcinomas (SCC) were positive for PD-L1 expression. Compared with ACC, the density of FOXP3+ cells in both the intratumoral region and peritumoral region was higher in SCC (P<0.01). The density of FOXP3+ cells was significantly higher than that of CD8+, CD16+, and CD163+ cells in SCC in the intratumoral region (P<0.01). In contrast, the density of FOXP3+ cells was significantly lower than that of CD8+, CD16+, and CD68+ cells in ACC in both the intratumoral region and peritumoral regions. The density of CD68+ cells was significantly higher than that of CD8+ cells (P<0.05) and CD163+ cells (P<0.01) in ACC in the intratumoral region. Furthermore, the tumors of patients with metastasis more commonly of immune-excluded status, in which the CD8+ cells accumulated in peritumoral region. CONCLUSIONS: This study demonstrated that the expression of PD-L1 in primary tracheobronchial neoplasm was mainly concentrated in patients with SCC. In the immune microenvironment of SCC, FOXP3+ cells were the dominant immune cells, while in the immune microenvironment of ACC, CD68+ cells were the main immune cells. Therefore, the immune microenvironment was significantly different in primary tracheobronchial neoplasm according to histology.
RESUMO
Erythropoiesis is a complex multistage process that involves differentiation of early erythroid progenitors to enucleated mature red blood cells, in which lineage-specific transcription factors play essential roles. Erythroid Krüppel-like factor (EKLF/KLF1) is a pleiotropic erythroid transcription factor that is required for the proper maturation of the erythroid cells, whose expression and activation are tightly controlled in a temporal and differentiation stage-specific manner. Here, we uncover a novel role of G-protein pathway suppressor 2 (GPS2), a subunit of the nuclear receptor corepressor/silencing mediator of retinoic acid and thyroid hormone receptor corepressor complex, in erythrocyte differentiation. Our study demonstrates that knockdown of GPS2 significantly suppresses erythroid differentiation of human CD34+ cells cultured in vitro and xenotransplanted in nonobese diabetic/severe combined immunodeficiency/interleukin-2 receptor γ-chain null mice. Moreover, global deletion of GPS2 in mice causes impaired erythropoiesis in the fetal liver and leads to severe anemia. Flow cytometric analysis and Wright-Giemsa staining show a defective differentiation at late stages of erythropoiesis in Gps2-/- embryos. Mechanistically, GPS2 interacts with EKLF and prevents proteasome-mediated degradation of EKLF, thereby increasing EKLF stability and transcriptional activity. Moreover, we identify the amino acids 191-230 region in EKLF protein, responsible for GPS2 binding, that is highly conserved in mammals and essential for EKLF protein stability. Collectively, our study uncovers a previously unknown role of GPS2 as a posttranslational regulator that enhances the stability of EKLF protein and thereby promotes erythroid differentiation.