Regulatory effects of WRAP53 on radiosensitivity of laryngeal squamous cell carcinoma cells.

Hui Qiu,De-Ying Zhao,Gong Zhang,Cong-Hua Xie,Li-Mei Yuan

doi:10.7314/apjcp.2015.16.7.2975

Abstract

Telomere length is closely associated with cellular radiosensitivity and WRAP53 is required for telomere addition by telomerase. In this research we assessed radiosensitivity of laryngeal squamous cell carcinoma Hep-2 cell lines after WRAP53 inhibition, and analyzed the molecular mechanisms. phWRAP53-siRNA and pNeg-siRNA were constructed and transfected into Hep-2 cells with lipofectamine. Expression of WRAP53 was analyzed by RT-PCR and Western-blottin, radiosensitivity of Hep-2 cells was assessed colony formation assay, and the relative length of telomeres was measured by QPCR. The data revealed that the plasmid of phWRAP53-siRNA was constructed successfully, and the mRNA and protein levels of WRAP53 were both obviously reduced in the Hep-2 cell line transfected with phWRAP53-siRNA. After Hep-2 cells were irradiated with X-rays, the D0 and SF2 were 2.481 and 0.472, respectively, in the phWRAP53-siRNA group, much lower than in the control group (D0 and SF2 of 3.213 and 0.592) (P<0.01). The relative telomere length in the phWRAP53-siRNA group was 0.185±0.01, much lower than in the untreated group (0.523±0.06) and the control group (0.435±0.01). Decreasing the expression of WRAP53 using RNA interference technique can enhance the radiosensitivity of Hep-2 cell lines by influencing the telomere length. WRAP53 is expected to be a new target to regulate the radiosensitization of tumor cells.

Highlights

Radiation therapy (RT) is an important kind of treatment in head and neck squamous cell carcinoma (HNSCC) patients, especially to the patients with locally advanced disease
Telomere length is closely associated with cellular radiosensitivity, the longer of the telomeres means that the tumor cells are more resistible to radiation (Fairlie et al, 2015; Laster et al, 2015)
The purpose of radiation copy number to single copy gene (S) copy number is sensitizing is to improve intrinsic radiosensitivity of tumor doubtless, and T/S is positively correlated with the mean cells to ionizing radiation and enhance the radiation effect to cancer cells, especially to irradiated resistant cells

Summary

Introduction

Radiation therapy (RT) is an important kind of treatment in head and neck squamous cell carcinoma (HNSCC) patients, especially to the patients with locally advanced disease. Most of patients with laryngeal squamous cell carcinoma can acquire satisfactory curative effect, a few patients have poor outcome due to resistance to radiation. It is reported that the radiation resistance almost accounts for 50% in all patients of treatment failure with laryngeal squamous cell carcinoma (Arshad et al, 2014; Megwalu et al, 2014; Mok et al, 2014). Telomere length is closely associated with cellular radiosensitivity, the longer of the telomeres means that the tumor cells are more resistible to radiation (Fairlie et al, 2015; Laster et al, 2015). In this research we assessed radiosensitivity of laryngeal squamous cell carcinoma Hep-2 cell lines after WRAP53 inhibition, and analyzed the molecular mechanisms. Expression of WRAP53 was analyzed by RT-PCR and Western-blottin, radiosensitivity of Hep-2 cells was assessed colony formation assay, and the relative length of telomeres was measured by QPCR. WRAP53 is expected to be a new target to regulate the radiosensitization of tumor cells

Methods

Results

Conclusion