Regulatory Effects of WRAP53 on Radiosensitivity of Laryngeal Squamous Cell Carcinoma Cells

Background: Telomere length is closely associated with cellular radiosensitivity and WRAP53 is required fortelomere addition by telomerase. In this research we assessed radiosensitivity of laryngeal squamous cell carcinomaHep-2 cell lines after WRAP53 inhibition, and analyzed the molecular mechanisms. Materials and
Methods: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 wasassessed colony formation assay, and the relative length of telomeres was measured by QPCR.
Results: The datarevealed that the plasmid of phWRAP53-siRNA was constructed successfully, and the mRNA and protein levelsof WRAP53 were both obviously reduced in the Hep-2 cell line transfected with phWRAP53-siRNA. After Hep-2cells were irradiated with X-rays, the D0 and SF2 were 2.481 and 0.472, respectively, in the phWRAP53-siRNAgroup, much lower than in the control group (D0 and SF2 of 3.213 and 0.592) (P<0.01). The relative telomerelength 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).
Conclusions: Decreasing the expression of WRAP53 using RNA interferencetechnique can enhance the radiosensitivity of Hep-2 cell lines by influencing the telomere length. WRAP53 isexpected to be a new target to regulate the radiosensitization of tumor cells.