Background:The sensitivity of nasopharyngeal carcinoma (NPC) cells to radiation is the primary factor influencing the therapeutic effect of radiotherapy for patients with NPC. This study aimed to investigate the mechanism underlying the potential regulatory effect of long non-coding RNA (lncRNA) RHPN1-AS1 on the radiosensitivity of NPC cells.
Methods:Weighted gene co-expression network analysis (WGCNA) was used to identify the modules and genes associated with radiotherapy sensitivity, which were validated with pre-radiotherapy biopsy specimens from 40 patients with NPC. The effects of RHPN1-AS1 on NPC cell radiosensitivity under irradiation were verified through in vivo and in vitro experiments. The interaction between RHPN1-AS1 and CELF2 was further investigated.
Results:WGCNA and NPC biopsy specimen-based validation indicated that RHPN1-AS1 was associated with radiotherapy sensitivity in NPC. Under irradiation conditions, silencing RHPN1-AS1 significantly inhibited the proliferation, migration, and invasion of NPC cells; promoted the expression of DNA double-strand break markers (γ-H2AX and 53BP1); induced DNA damage; and promoted apoptosis. RNA immunoprecipitation and Western blot assays further confirmed that RHPN1-AS1 negatively regulated CELF2 expression. After sequential transfection with RHPN1-AS1 small interfering RNA (siRNA) and CELF2 siRNA, clone formation assay, Cell Counting Kit-8 assay, and flow cytometry demonstrated that silencing CELF2 reversed the suppressive effects of si-RHPN1-AS1 on NPC cell proliferation, viability, and invasion while promoting its effect on apoptosis. Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene set enrichment analyses revealed that CELF2 expression significantly influenced the MAPK signaling pathway. Quantitative real-time polymerase chain reaction (RT-qPCR) and Western blot analysis confirmed that high CELF2 expression promoted MAPK signaling pathway activation. Silencing RHPN1-AS1 significantly increased the protein levels of phosphorylation of p38 (p-p38) and p-JNK in the MAPK pathway and abolished the inhibitory effect of CELF2 silencing on the MAPK pathway.
Conclusions:This study confirmed that RHPN1-AS1 expression inhibits the radiosensitivity of NPC cells. RHPN1-AS1 may affect NPC radiotherapy sensitivity by targeting CELF2 to regulate the MAPK pathway.
