Identifying optimal candidates for postoperative adjuvant therapy among regional persistent/recurrent nasopharyngeal carcinoma patients after neck dissection.

PURPOSE: To analyze the clinical outcomes of patients with regional persistent/recurrent nasopharyngeal carcinoma (NPC) who received neck dissection, and to evaluate the clinical benefit of postoperative adjuvant therapy (PAT) based on patients' positive lymph node counts (PLNs), extracapsular spread (ECS) and preoperative plasma EBV DNA levels. METHODS: From 2003 to 2017, 342 patients with regional persistent/recurrent NPC were included in this study. All patients were treated with neck dissection and 76 patients received PAT. Progression-free survival (PFS), overall survival (OS), distant metastasis-free survival (DMFS) and locoregional relapse-free survival (LRFS) were compared between groups using propensity score matching (PSM). RESULTS: 152 patients without PAT treatment and 76 patients with PAT treatment were selected by the PSM. There was no significant difference in 2-year PFS (52.4% vs. 61.3%, P = 0.371), 2-year OS (91.9% vs. 90.5%, P = 0.097) or 2-year LRFS (66.3% vs. 67.9%, P = 0.872) between the two groups. However, the application of PAT brought survival benefits to patients in terms of 2-year DMFS (76.5% vs. 84.7%, P = 0.020). PLN, ECS and preoperative EBV DNA level remained independent risk factors for poorer PFS. Accordingly, patients were divided into low-risk and high-risk groups using receiver operating characteristic (ROC) curve; the 2-year PFS rates for two risk groups were 73.4% and 59.1% (P < 0.0001) respectively. The results showed that low-risk patients didn't benefit from the addition of PAT. However, the 2-year DMFS rate was significantly improved in high-risk PAT-treated patients than those treated by neck dissection alone (83.7% vs. 71.7%, P = 0.023). CONCLUSIONS: PLNs, ECS and preoperative EBV DNA level are associated with the prognosis of patients with regional persistent/recurrent NPC. High-risk patients identified by PLNs, ECS and preoperative EBV DNA level may benefit from the addition of PAT after neck dissection.

Exosomal miR-24-3p impedes T-cell function by targeting FGF11 and serves as a potential prognostic biomarker for nasopharyngeal carcinoma.

Recent studies have shown that extracellular microRNAs are not only potential biomarkers but are also involved in cell interactions to regulate the intercommunication between cancer cells and their microenvironments in various types of malignancies. In this study, we isolated exosomes from nasopharyngeal carcinoma (NPC) cell lines and patient sera (T-EXOs), or control NP69 cells and healthy donor sera (HD-EXOs). We found that miR-24-3p was markedly enriched in T-EXOs as compared with HD-EXOs; the serum exosomal miR-24-3p level was correlated with worse disease-free survival of patients (p < 0.05). Knockdown of exosomal miR-24-3p (miR-24-3p-sponge-T-EXOs) by a sponge RNA targeting miR-24-3p restored the T-EXO-mediated (control-sponge-T-EXO) inhibition of T-cell proliferation and Th1 and Th17 differentiation, and the induction of regulatory T cells (Tregs). Mechanistic analyses revealed that administration of exosomal miR-24-3p increased P-ERK, P-STAT1 and P-STAT3 expression while decreasing P-STAT5 expression during T-cell proliferation and differentiation. Moreover, by in vivo and in vitro assessments, we found FGF11 to be a direct target of miR-24-3p. However, both miR-24-3p-sponge-T-EXOs and T-EXOs (control-sponge-T-EXOs) impeded proliferation and Th1 and Th17 differentiation, but induced Treg differentiation, of lenti-shFGF11-transfected T cells. The levels of phosphorylated ERK and STAT proteins were different in lenti-ScshRNA-transfected T cells and lenti-shFGF11-transfected T cells following administration of miR-24-3p-sponge-T-EXO. Interestingly, tumour FGF11 expression was positively correlated with the number of CD4+ and CD8+ T cells in vivo, and predicted favourable patient DFS (p < 0.05). Additionally, hypoxia increased cellular and exosomal miR-24-3p levels and enhanced the inhibitory effect of T-EXO on T-cell proliferation and differentiation. Collectively, our findings suggest that exosomal miR-24-3p is involved in tumour pathogenesis by mediating T-cell suppression via repression of FGF11, and may serve as a potential prognostic biomarker in NPC. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Retraction notice to "Endogenous production of C-C motif chemokine ligand 2 by nasopharyngeal carcinoma cells drives radioresistance-associated metastasis" [Canc. Lett. 468 (2020) 27-40].

This article has been retracted: please see Elsevier Policy on Article Withdrawal (https://www.elsevier.com/about/our-business/policies/article-withdrawal). .

Single-cell transcriptomic analysis defines the interplay between tumor cells, viral infection, and the microenvironment in nasopharyngeal carcinoma.

Nasopharyngeal carcinoma (NPC) is an Epstein-Barr virus (EBV)-associated malignancy with a complex tumor ecosystem. How the interplay between tumor cells, EBV, and the microenvironment contributes to NPC progression and immune evasion remains unclear. Here we performed single-cell RNA sequencing on ~104,000 cells from 19 EBV+ NPCs and 7 nonmalignant nasopharyngeal biopsies, simultaneously profiling the transcriptomes of malignant cells, EBV, stromal and immune cells. Overall, we identified global upregulation of interferon responses in the multicellular ecosystem of NPC. Notably, an epithelial-immune dual feature of malignant cells was discovered and associated with poor prognosis. Functional experiments revealed that tumor cells with this dual feature exhibited a higher capacity for tumorigenesis. Further characterization of the cellular components of the tumor microenvironment (TME) and their interactions with tumor cells revealed that the dual feature of tumor cells was positively correlated with the expression of co-inhibitory receptors on CD8+ tumor-infiltrating T cells. In addition, tumor cells with the dual feature were found to repress IFN-γ production by T cells, demonstrating their capacity for immune suppression. Our results provide new insights into the multicellular ecosystem of NPC and offer important clinical implications.

Endogenous production of C-C motif chemokine ligand 2 by nasopharyngeal carcinoma cells drives radioresistance-associated metastasis.

Patients with recurrent nasopharyngeal carcinoma (NPC) have more co-existing distant metastasis than those of no-recurrence and are more likely to suffer distant metastasis after re-irradiation than patients with newly diagnosed NPC. However, the relationship between radioresistance and distant metastasis and the mechanisms involved in radioresistance-associated metastasis are still unclear. In this study, we proved that C-C motif chemokine ligand 2 (CCL2) expression was significantly elevated in HONE1-IR cells and recurrent NPC tumour. Inhibition of CCL2 enhanced sensitivity to radiotherapy in NPC cells. Moreover, autocrine CCL2 promoted NPC cell adaptive radioresistance, metastasis and epithelial-mesenchymal transition. Additionally, p53 activated CCL2 transcription. High CCL2 expression was highly associated with poorer locoregional recurrence free survival, progression free survival and overall survival in patients with newly diagnosed NPC. Notably, high CCL2 expression was an independent prognostic factor for distant metastasis free survival in recurrent NPC patients. Our results provide insights into the autocrine signalling mechanisms of CCL2 and suggest that inhibition of autocrine CCL2 may be a candidate treatment strategy for management of radioresistant NPC.

PERK Signal-Modulated Protein Translation Promotes the Survivability of Dengue 2 Virus-Infected Mosquito Cells and Extends Viral Replication.

Survival of mosquitoes from dengue virus (DENV) infection is a prerequisite of viral transmission to the host. This study aimed to see how mosquito cells can survive the infection during prosperous replication of the virus. In C6/36 cells, global protein translation was shut down after infection by DENV type 2 (DENV2). However, it returned to a normal level when infected cells were treated with an inhibitor of the protein kinase RNA (PKR)-like ER kinase (PERK) signaling pathway. Based on a 7-Methylguanosine 5'-triphosphate (m7GTP) pull-down assay, the eukaryotic translation initiation factor 4F (eIF4F) complex was also identified in DENV2-infected cells. This suggests that most mosquito proteins are synthesized via canonical cap-dependent translation. When the PERK signal pathway was inhibited, both accumulation of reactive oxygen species and changes in the mitochondrial membrane potential increased. This suggested that ER stress response was alleviated through the PERK-mediated shutdown of global proteins in DENV2-infected C6/36 cells. In the meantime, the activities of caspases-9 and -3 and the apoptosis-related cell death rate increased in C6/36 cells with PERK inhibition. This reflected that the PERK-signaling pathway is involved in determining cell survival, presumably by reducing DENV2-induced ER stress. Looking at the PERK downstream target, α-subunit of eukaryotic initiation factor 2 (eIF2α), an increased phosphorylation status was only shown in infected C6/36 cells. This indicated that recruitment of ribosome binding to the mRNA 5'-cap structure could have been impaired in cap-dependent translation. It turned out that shutdown of cellular protein translation resulted in a pro-survival effect on mosquito cells in response to DENV2 infection. As synthesis of viral proteins was not affected by the PERK signal pathway, an alternate mode other than cap-dependent translation may be utilized. This finding provides insights into elucidating how the PERK signal pathway modulates dynamic translation of proteins and helps mosquito cells survive continuous replication of the DENV2. It was ecologically important for virus amplification in mosquitoes and transmission to humans.