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

Abstract

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.

A positive feedback loop between Wnt/β‐catenin signaling and hTERT regulates the cancer stem cell‐like traits in radioresistant nasopharyngeal carcinoma cells

“…[9][10][11] In previous research, we found that CNE-2R cells also displayed CSC-like traits and a high level of telomerase activity. 12 Telomerase activity is closely related to CSCs, 15,16 which is considered to be essential for CSCs to progress, self-renew, and immortalize. 17 hTERT is an indispensable catalytic subunit to maintain the telomerase activity, which can regulate the telomerase activity at the transcription level.…”

“…In the previous study, we discovered that the radioresistant NPC cell line CNE-2R displayed CSC-like traits and a high level of telomerase activity, as well as highly expressed human telomerase reverse transcriptase (hTERT). 12 Due to strict transcriptional suppression of the hTERT gene, telomerase activity is absent in most normal human somatic cells. 13 However, expression of hTERT and telomerase activity can be observed in as high as 90% of human malignant tumors.…”

Role of Telomeres Shortening in Atherogenesis: An Overview

“…For example, increased mTERT (mouse) expression can accelerate skin wound healing and promote carcinogenesis without affecting telomere length [ 17 ]. Forced expression of telomerase can modify the inner functions of stem cells [ 18 ].…”

Comparative Analysis of Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells between Preeclampsia and Normal Pregnant Women

“…The absorbance was measured in triplicate at 450 nm, by reading against a blank (reference absorbance at 690 nm). Samples were regarded as telomerase-positive if the difference in absorbance (A 450 − A 690 ) was greater than 0.2 [49,50].…”