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.

The role of autophagy in the radiosensitivity of the radioresistant human nasopharyngeal carcinoma cell line CNE-2R.

PURPOSE: The present study aimed to study the role of autophagy in the radiosensitivity of the radioresistant human nasopharyngeal carcinoma cell line CNE-2R. METHODS: Before being irradiated, CNE-2R cells were treated with the autophagy inhibitor chloroquine diphosphate (CDP) or the autophagy inducer rapamycin (RAPA). Microtubule-associated protein light chain 3 (LC3-II) and p62 were assessed using Western blotting analysis 48 hours after CNE-2R cells were irradiated. The percentage of apoptotic cells was assessed via flow cytometry. CNE-2R cell viability was evaluated using the Cell Counting Kit-8 (CCK8). The radiosensitivity of cells was assessed via clone formation analysis. RESULTS: The level of autophagy in CNE-2R cells improved as the radiation dose increased, reaching the maximum at a dose of 10 Gy. Autophagy was most significantly inhibited by 60 µmol/L CDP in CNE-2R cells, but was obviously enhanced by 100 nmol/L RAPA. Compared with the irradiation (IR) alone group, in the IR + CDP group, autophagy was significantly inhibited, viability was low, the rate of radiation-induced apoptosis was increased, and radiosensitivity was upregulated. In contrast, cells of the IR + RAPA group exhibited greater autophagy, higher viability, a lower rate of radiation-induced apoptosis, and downregulated radiosensitivity. CONCLUSION: The autophagy level is negatively correlated with radiosensitivity for the radio-resistant human nasopharyngeal carcinoma cell line CNE-2R.

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.

Cetuximab or Nimotuzumab Versus Cisplatin Concurrent with Radiotherapy for Local-Regionally Advanced Nasopharyngeal Carcinoma: a Meta-analysis

Background: It is unclear whether Cetuximab (CTX) or Nimotuzumab (NTZ) concurrent with radiotherapy delivers equivalent or improved results with fewer toxicities over standard cisplatin (CDDP) concurrent with radiotherapy in locally advanced nasopharyngeal carcinoma (NPC). Methods: The strategy involved searching the PubMed, Embase, Cochrane Library, China National Knowledge Internet Web, Wanfang and Chinese Biomedical databases. Controlled clinical trials that compared concurrent CTX/NTZ with radiotherapy versus CDDP with radiotherapy in local-regionally advanced NPC were included. Results: In all, 1,239 patients in six clinical trials were included in the analysis. The hazard ratios (HRs) between the CTX/NTZ and CDDP groups were 1.01 (95% confidence interval (CI) 0.63-1.64), 1.06 (95% CI 0.50-2.25), 1.04 (95% CI 0.61-1.76), and 1.05 (95% CI 0.73-1.50) for overall survival, local-regional failure-free survival, distant metastasis failure-free survival, and disease-free survival, respectively. Significant differences were found in the incidences of grade 3-4 anaemia [Risk ratio (RR) 0.11 95% CI 0.02-0.58], grade 3-4 neutropenia (RR 0.23 95% CI 0.12- 0.44), grade 3-4 thrombocytopenia (RR 0.31 95% CI 0.12- 0.79), and grade 3-4 vomiting (RR 0.04 95% CI 0.00-0.29) in favour of the CTX/NTZ group. However, the patients in the CTX/NTZ group experienced a higher incidence of grade 3-4 skin rash (RR 6.45 95% CI 3.84-10.84). Conclusions: Regarding the efficacy and side effects, the combination of CTX / NTZ and radiotherapy may be an alterative treatment regimen of standard CDDP concurrent with radiotherapy in local-regionally advanced NPC, especially in patients who cannot tolerate or who refuse chemotherapy.

Cofilin-2 Acts as a Marker for Predicting Radiotherapy Response and Is a Potential Therapeutic Target in Nasopharyngeal Carcinoma.

BACKGROUND The purpose of this study was to determine whether cofilin-2 could serve as a protein marker for predicting radiotherapy response and as a potential therapeutic target in nasopharyngeal carcinoma (NPC). MATERIAL AND METHODS Cofilin-2 protein levels in serum and tissue samples from patients with NPC were assessed by sandwich ELISA and IHC. In vitro, cofilin-2 levels in CNE-2R cells were significantly higher than those of CNE-2 cells. Meanwhile, CNE-2R cells were silenced for cofilin-2 to obtain a stable cofilin-2-RNAi-LV3 cell line. Then, cell proliferation, radiosensitivity, invasion and migration abilities, cell cycle, and apoptosis were evaluated by Cell Counting Kit 8 assay (CCK-8), flow cytometry (FCM), clone formation assay, and in vitro. RESULTS The secreted levels of the cofilin-2 protein in radioresistant NPC patients were significantly higher than those of radiosensitive cases. After cofilin-2 knockdown in nasopharyngeal carcinoma CNE-2R cells, proliferation was decreased, while apoptosis and radiosensitivity were enhanced; cell cycle distribution was altered, and the transplanted tumors in nude mice grew significantly less. CONCLUSIONS Overall, our findings suggest that cofilin-2 acts as a marker for predicting radiotherapy response and is a potential therapeutic target in nasopharyngeal carcinoma.

Reduced QSOX1 enhances radioresistance in nasopharyngeal carcinoma.

Radioresistance is a major cause leads to treatment failure in nasopharyngeal carcinoma (NPC). In our previous study, we identified that QSOX1 is a differentially expressed protein in NPC cell lines with variable radiosensitivities. The present study aimed to investigate the biological behavior of QSOX1 in nasopharyngeal carcinoma (NPC) and its effect on radiosensitivity. The levels of QSOX1 detected by enzyme-linked immunosorbent assay (ELISA) and immunohistochemistry (IHC) in radioresistant NPC patient sera and tissue samples were markedly lower than those in radiosensitive samples. Small hairpin RNAs (shRNAs) were employed to knock down endogenous QSOX1 expression in CNE-2 cells, and then, radiosensitivity, apoptosis, migration and invasion were assessed using colony formation, Cell Counting Kit-8 (CCK-8), flow cytometry, and transwell assays, respectively. Tumor growth and radioresistance were also evaluated using a xenograft model in nude mice. The shRNA-mediated knockdown of QSOX1 significantly increased cell survival under irradiation (IR) and weakened radiosensitivity, which was likely due to a reduction in the cell apoptosis rate after IR. Moreover, QSOX1 silencing led to the suppression of cellular migration and invasion. Similar results were obtained with the xenograft mouse model. Thus, targeting QSOX1 will provide a new avenue for increasing the sensitivity of NPC to radiotherapy.

Significant survival benefit of adjuvant chemotherapy after concurrent chemoradiotherapy in locally advanced high-risk nasopharyngeal carcinoma.

The present study aimed to define high-risk patients who may benefit from additional adjuvant chemotherapy (AC) after concurrent chemotherapy in combination with intensity-modulated radiotherapy among patients with loco-regionally advanced nasopharyngeal carcinoma (NPC). A cohort of 511 NPC patients who received concomitant chemoradiotherapy (CCRT) with or without AC between January 2007 and December 2012 were retrospectively analysed. One hundred seventy-seven patients received CCRT alone, whereas 334 received CCRT + AC. The survival analysis showed that ages >45 years old, T3-T4 stages, N2-N3 disease and serum albumin levels ≤42 g/L were significant independent prognostic factors for overall survival (OS). Using these four risk factors, a prognostic model for OS was created as follows: (1) low-risk group: 0-1 risk factors; and (2) high-risk group: 2-4 risk factors. In the CCRT alone and CCRT + AC groups, significant differences in survival were found between the high- and low-risk groups. Patients in the high-risk group exhibited improved OS due to the addition of AC to CCRT, but no survival benefits were found in the low-risk group. In conclusion, high-risk patients may benefit from the addition of AC to CCRT regarding OS.