Contribution of age at diagnosis to cancer-specific survival of nasopharyngeal carcinoma patients receiving radiotherapy.

To assess age as a continuous variable for the prognosis of patients with nasopharyngeal carcinoma (NPC) receiving radiotherapy. Patients diagnosed with NPC between 2004 and 2016 were extracted from the Surveillance, Epidemiology, and End Results database. The X-tile was used to calculate the optimal cutoff values for age at diagnosis. Age at diagnosis was divided into subgroups based on the cutoff values. Cancer-specific survival (CSS) between age subgroups was assessed using the Kaplan-Meier method. The age cutoff values for CSS were 42 and 70 years. The 5-year CSS was 85.8%, 73.8%, and 67.1% for the ≤42, 43 to 70, and >70 subgroups. Multivariate regression analysis revealed that race, pathology, T stage, N stage, and age were independent prognostic factors. A nomogram based on the prognostic factors showed that the area under the receiver operating characteristic curve was 0.723 (95% confidence interval, 0.697-0.749). The calibration plots showed good agreement for the 5-year CSS between the predicted and actual observations. All patients were divided into 3 groups according to risk score stratification. Kaplan-Meier survival analyses showed that patients in the low-risk cohort had a greater 5-year CSS than those in the medium- and high-risk cohorts (P < .05). Age subgroups of ≤42, 43 to 70, and >70 years may be useful for determining the prognosis of patients with NPC.

Causal relationships between gut microbiota and programmed cell death protein 1/programmed cell death-ligand 1: A bidirectional Mendelian randomization study.

Background: Multiple clinical studies have indicated that the gut microbiota influences the effects of immune checkpoint blockade (ICB) therapy comprising PD-1/PD-L1 inhibitors, but the causal relationship is unclear. Because of numerous confounders, many microbes related to PD-1/PD-L1 have not been identified. This study aimed to determine the causal relationship between the microbiota and PD-1/PD-L1 and identify possible biomarkers for ICB therapy. Method: We used bidirectional two-sample Mendelian randomization with two different thresholds to explore the potential causal relationship between the microbiota and PD-1/PD-L1 and species-level microbiota GWAS to verify the result. Result: In the primary forward analysis, genus_Holdemanella showed a negative correlation with PD-1 [ßIVW = -0.25; 95% CI (-0.43 to -0.07); PFDR = 0.028] and genus_Prevotella9 showed a positive correlation with PD-1 [ßIVW = 0.2; 95% CI (0.1 to 0.4); PFDR = 0.027]; order_Rhodospirillales [ßIVW = 0.2; 95% CI (0.1 to 0.4); PFDR = 0.044], family_Rhodospirillaceae [ßIVW = 0.2; 95% CI (0 to 0.4); PFDR = 0.032], genus_Ruminococcaceae_UCG005 [ßIVW = 0.29; 95% CI (0.08 to 0.5); PFDR = 0.028], genus_Ruminococcus_gnavus_group [ßIVW = 0.22; 95% CI (0.05 to 0.4); PFDR = 0.029], and genus_Coprococcus_2 [ßIVW = 0.4; 95% CI (0.1 to 0.6); PFDR = 0.018] were positively correlated with PD-L1; and phylum_Firmicutes [ßIVW = -0.3; 95% CI (-0.4 to -0.1); PFDR = 0.031], family_ClostridialesvadinBB60group [ßIVW = -0.31; 95% CI (-0.5 to -0.11), PFDR = 0.008], family_Ruminococcaceae [ßIVW = -0.33; 95% CI (-0.58 to -0.07); PFDR = 0.049], and genus_Ruminococcaceae_UCG014 [ßIVW = -0.35; 95% CI (-0.57 to -0.13); PFDR = 0.006] were negatively correlated with PD-L1. The one significant species in further analysis was species_Parabacteroides_unclassified [ßIVW = 0.2; 95% CI (0-0.4); PFDR = 0.029]. Heterogeneity (P > 0.05) and pleiotropy (P > 0.05) analyses confirmed the robustness of the MR results.

Cancer stem cell-like characteristics and telomerase activity of the nasopharyngeal carcinoma radioresistant cell line CNE-2R.

The radioresistance of nasopharyngeal carcinoma (NPC) may be related to cancer stem cells (CSCs), and the characteristics of CSCs may be maintained by telomerase activity. In this study, we explored the CSC-like characteristics and telomerase activity of the NPC radioresistant cell line CNE-2R. This work provides a foundation for future studies on stem cell-targeted therapies by targeting the radioresistance of NPC. The expression of stem cell-related genes/proteins and the hTERT gene/protein in CNE-2R and its parent radiosensitive cell line CNE-2 were detected using qPCR/Western Blot. Label-retaining cells (LRCs) were detected through immunocytochemistry, and telomerase activity was detected using a PCR-ELISA kit. CD133 expression was detected with flow cytometry. CNE-2R-CD133+ and CNE-2R-CD133- cells were separated with magnetic-activated cell sorting. The proliferation and tumorigenesis capacities of CNE-2R-CD133+, CNE-2R-CD133-, and CNE-2R cells were compared with a CCK-8 assay, sphere formation assay, and an in vivo experiment. Our results showed that the expression of stem cell-related genes and the hTERT gene in CNE-2R cells was higher than those in CNE-2 cells. Similarly, the expression of stem cell-related proteins and the hTERT protein in CNE-2R cells was markedly higher than those in CNE-2 cells. The proportion of LRCs in CNE-2R and CNE-2 cells was (3.10 ± 0.63%) vs (0.40 ± 0.35%; P < 0.001), respectively. Telomerase activity in CNE-2R cells was remarkably higher than that in CNE-2 cells. Flow cytometry suggested that the CD133 positive rates in CNE-2R and CNE-2 cells were (2.49 ± 0.56%) vs (0.76 ± 0.25%; P = 0.008), respectively. Meanwhile, the proliferation capacity, tumorigenesis capacity, and telomerase activity of CNE-2R-CD133+ cells were notably higher than those of CNE-2R-CD133- and CNE-2R cells. Collectively, CNE-2R displayed CSC-like characteristics; our results also showed that CNE-2R cells, especially the sorted CSCs, had high telomerase activity levels.

Serum CD166: A novel biomarker for predicting nasopharyngeal carcinoma response to radiotherapy.

The present study aimed to identify whether CD166 can be used as a biomarker for predicting the response of nasopharyngeal carcinoma (NPC) to radiotherapy. The serum concentration of CD166 in patients with NPC were detected by enzyme-linked immunosorbent assay. The secreted level of CD166 with radioresistant NPC was significantly higher than that with radiosensitive NPC. In vitro, the CD166 positive rate in the CNE2 cell membrane was significantly lower than that in the CNE2R cell membrane. The magnetic-activated cell sorting technology was used to obtain CNE-2R-CD166(+) and CNE-2R-CD166(-) cell lines. Then radiosensitivity, cell proliferation, and apoptosis were assessed using colony formation assay, cell counting kit 8 assay (CCK-8), and flow cytometry, respectively. The radiation sensitivity ratio was 1.28, indicating that the CNE2R-CD166(-) cells had a stronger radiation sensitivity. The result of CCK-8 assay indicated that the survival fraction of CNE2R-CD166(+) cells was significantly higher than that of CNE2R-CD166(-) cells. The apoptotic rate of CNE2R-CD166(+) cells was significantly lower than that of CNE2R-CD166(-) cells. Our data demonstrate that the secreted protein CD166 may be can used as a biomarker for predicting the response of NPC to radiotherapy.

Analysis of the differential secretome of nasopharyngeal carcinoma cell lines CNE-2R and CNE-2.

Radioresistance is the major cause of poor prognosis in nasopharyngeal carcinoma (NPC). To identify and characterize the secretome associated with NPC radioresistance, we compared the conditioned serum-free medium of radioresistant CNE-2R cells with that of the parental radiosensitive CNE-2 cells using isobaric tags for relative and absolute quantitation (iTRAQ) with liquid chromatography-electrospray tandem mass spectrometry (LC-ESI-MS/MS) quantitative proteomics. Before proceeding to quantitative proteomics, we investigated the survival curves of CNE-2R and CNE-2 cells by colony formation assay, and the CNE-2R survival curves were significantly higher than those for CNE-2. In total, 3,581 proteins were identified in the quantitative proteomics experiments, and 40 proteins exhibited significant differences between the CNE-2R and CNE-2 cells. Twenty-six of the 40 proteins were secreted by classical, non-classical, or exosomal secretion pathways. To verify the reliability of iTRAQ quantitative proteomics, we applied western blotting (WB) to study the secretory protein expression of fibrillin-2, CD166, sulfhydryl oxidase 1 and cofilin-2, which are involved in cell adhesion, migration and invasion. The WB results showed that fibrillin-2 (p=0.017) and sulfhydryl oxidase 1 (p=0.000) were highly expressed in the CNE-2 cells, while CD166 (p=0.012) and cofilin-2 (p=0.003) were highly expressed in the CNE-2R cells, which was in accordance with iTRAQ quantitative proteomics. Finally, a phenotypic subset of CD166-positive NPC cells was verified by immunocytochemistry. In summary, we defined a collection of secretory proteins that may be relevant to the radioresistance in NPC cells, and we determined that CD166, which is widely used as a positive marker of cancer stem cells, is expressed in NPC cells.