Background Distant metastasis remained the major cause of mortality in nasopharyngeal carcinoma (NPC) receiving radiotherapy despite favorable locoregional control in the past decades. Tumor microenvironment plays a critical role in tumor progression by secreting factors that regulate cancer cell metastasis. We explored the role of secreted protein Slit2 in NPC metastasis and the underlying mechanisms. Methods Colony formation assay were determined the opitimal dose. Using real-time PCR, western blotting, and ELISA, we detected the expression of Slit2 in NPC cells and in supernatant. Cell migration assay and cell invasion assay were examined the role of Slit2 in promoting metastasis of NPC cell lines. Western blotting, immunofluorescence staining, transwell and Co-IP assay et al. were performed to explore the detailed molecular mechanism of Slit2 in NPC. Finally, we estimated the effects on Slit2-shRNA NPC cells in vivo tumor metastasis experiment Results We found that irradiated dying NPC cells could secrete Slit2 to enhance the metastatic ability of surviving NPC cells. Mechanistic study showed that Slit2 interacted with its cognate Robo1 receptor, which activated PI3K/Akt pathway and enhanced the nuclear translocation of β-catenin to promote NPC metastasis. Finally, we demonstranted that knockdown of Slit2 in NPC cells significantly suppressed lung and liver metastasis. Conclusion Slit2, a secreted factor released from irradiated dying NPC cells could promote metastasis of living/resistent NPC cells through PI3K/AKT/β-catenin pathway. Tumor microenvironment altered by irradiated dying cancer cells may be promising target to treat cancer metastasis.

Background: Concurrent chemoradiotherapy (CCRT) is a cornerstone of treatment for locally advanced cervical cancer, although many patients show a poor response. The tumor microenvironment (TME) is a key determinant of therapeutic resistance and prognosis, with the metabolic reprogramming within specific cellular subsets playing a particularly important role. However, the cellular sources of metabolic heterogeneity in cervical cancer and their clinical implications have yet to be firmly established. Methods: An integrated analysis of single-cell RNA sequencing (scRNA-seq) datasets from eight patients cervical cancer, together with bulk RNA sequencing data retrieved from The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets, was conducted. Cellular heterogeneity was characterized using the Seurat and Harmony, while metabolic activity was assessed by integrating five algorithms (AUCell, UCell, singscore, ssGSEA, and AddModuleScore). The Least Absolute Shrinkage and Selection Operator (LASSO)-Cox regression was used to construct a prognostic model, which was subsequently validated in external cohorts. The functional role of the key gene FSTL3 was examined through both in vitro and in vivo experiments. Results: scRNA-seq analyses identified 10 major cell types within the cervical cancer TME. Among these, cancer-associated fibroblasts (CAFs) showed the greatest enrichment of ketone body metabolism-related gene signatures. CAFs with high enrichment of these signatures exhibited enhanced cell–cell communication and were associated with activation of the AP-1 transcription factor network. Analysis of these CAFs led to the development of a nine-gene prognostic signature (KLF4, SERPINF1, CD74, PRPS2, ERRFI1, FSTL3, SOD2, JUN, and CXCL3). A risk model based on these genes predicted survival in the TCGA training and validation sets and in independent GEO cohorts (disease-free survival in GSE44001 and overall survival in GSE52903). A nomogram combining the risk score with clinical variables showed improved predictive performance compared with either the risk score or clinical variables alone. Knockdown of FSTL3 suppressed tumor growth and enhanced sensitivity to irradiation and cisplatin in both in vitro and in vivo models, supporting its functional role in cervical cancer progression and treatment response. Conclusion: These analyses identify a CAF population enriched in ketone body metabolism-related gene expression that may be associated with cervical cancer progression. In addition to establishing a prognostic model for further evaluation, this study identifies FSTL3 as a potential therapeutic target that warrants further mechanistic and pharmacological investigation.

Purpose The objectives of this study were to analyze the prognostic factors of patients with distant metastasis after intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC) and to provide a reference for the clinical treatment of these patients. Methods A retrospective analysis was conducted among 152 patients with distant metastasis after IMRT for NPC from January 2006 to December 2017 (median follow-up, 43 months). The survival rates were calculated and compared using the Kaplan-Meier method and log-rank tests, respectively. The Cox risk ratio model was used for univariateand multivariate analyses. Results Among all patients, the median interval from treatment completion to distant metastasis was 11.3 months. The median post-metastasis survival was 14 months, and the 1-, 2-, and 3-year survival rates were 60.4%, 40.2%, and 27.6%, respectively. Upon univariate analysis, overall survival was found to be related to the N stage and induction chemotherapy at initial diagnosis, time from initial radiotherapy completion to distant metastasis, liver metastasis, and chemotherapy and palliative radiotherapy after metastasis. Liver metastasis, multi-organ metastasis, chemotherapy after metastasis, and the time from radiotherapy completion to distant metastasis were independent prognostic factors for patient survival in the Cox regression analysis. Conclusions The prognosis of patients with distant metastasis after IMRT for NPC was related to the time from radiotherapy completion to distant metastasis, regardless of liver or multiple organ metastasis and adjuvant chemotherapy after metastasis. Adequate adjuvant chemotherapy and local palliative radiotherapy could potentially prolong the survival of patients with distant metastasis of NPC.