Development and validation of prognostic nomograms in patients with ascending type of nasopharyngeal carcinoma: Retrospective study based on SEER database.

BACKGROUND: Nomograms specifically used to predict the prognosis of ascending type nasopharyngeal carcinoma (NPC) have not been constructed. METHODS: Data of ascending type (T3-4N0-1M0) NPC from the Surveillance, Epidemiology, and End Results (SEER) database between 2004 and 2015 were extracted. RESULTS: Altogether 862 patients with ascending type NPC were enrolled, including 603 in training cohort and 259 in validation cohort. Age, marital status, pathology, grade, tumor size, T classification, and chemotherapy were the independent prognostic factors for overall survival (OS). Age, marital status, pathology, grade, and chemotherapy were the independent prognostic factors for cancer-specific survival (CSS). In training cohort, the concordance index of the OS and CSS nomograms were 0.694 (95% confidence interval [CI], 0.677-0.711) and 0.678 (95%CI, 0.659-0.697), respectively, while those in validation cohort were 0.740 (95%CI, 0.715-0.765) and 0.708 (95%CI, 0.679-0.737), separately. CONCLUSION: The as-constructed nomograms for ascending type NPC could provide accurate prognostic predictions of OS and CSS.

Exosomes overexpressing miR-34c inhibit malignant behavior and reverse the radioresistance of nasopharyngeal carcinoma.

BACKGROUND: Malignant behavior and radioresistance, which severely limits the efficacy of radiation therapy (RT) in nasopharyngeal carcinoma (NPC), are associated with tumor progression and poor prognosis. Mesenchymal stem cells (MSCs) are used as a therapeutic tool in a variety of tumors. The aim of this study was to reveal the effect of tumor suppressor microRNA-34c-5p (miR-34c) on NPC development and radioresistance, as well as to confirm that exosomes derived from MSCs overexpressing miR-34c restore the sensitivity to radiotherapy in NPCs. METHODS: Potentially active microRNAs were screened by cell sequencing, Gene Expression Omnibus (GEO) database analysis, and analysis of clinical serum samples from 70 patients. The expression of genes and proteins was detected by Western blotting, quantitative reverse transcription PCR (qRT-PCR), and immunohistochemistry (IHC). Proliferation, apoptosis, invasion, migration and radioresistance of NPC were detected. Luciferase reporter assays were used to verify the interactions of microRNAs with their downstream targets. MSCs exosomes were isolated by ultrafiltration and verified by electron microscopy and nanoparticle tracking technology. RESULTS: The expression of miR-34c was associated with the occurrence and radiation resistance of NPC. In vitro and in vivo experiments indicated that overexpression of miR-34c inhibit malignant behavior such as invasion, migration, proliferation and epithelial-mesenchymal transition (EMT) in NPCs by targeting ß-Catenin. In addition, we found alleviated radioresistance upon miR-34c overexpression or ß-catenin knockdown in NPCs. Exosomes derived from miR-34c-transfected MSCs attenuated NPC invasion, migration, proliferation and EMT. Moreover, miR-34c-overexpressing exosomes drastically increased radiation-induced apoptosis in NPC cells. CONCLUSION: miR-34c is a tumor suppressor miR in NPC, which inhibits malignant behavior as well as radioresistance of tumor. Therefore, exogenous delivery of miR-34c to NPCs via MSC exosomes inhibits tumor progression and increases the efficiency of RT. Combination IR with miR-34c-overexpressing exosomes may be effective treatment for radioresistant NPCs.

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.

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.