Document Type : Original Article
Department of Medical Genetics, Faculty of Medical Sciences, Tarbiat Modares University, Tehran, Iran
Introduction: Radiotherapy is a standard and effective modality for breast cancer treatment, through induction of DNA damages notably DNA double-strand breaks which are involved in radiation-induced cell death. All radiation-induced DNA damages are subjected to various repair processes, therefore, interference in the DNA repair pathways might result in radio-resistance. Non-coding RNAs are a diverse group of functional RNA molecules that are not translated into proteins. Recent studies have shown that radiation can cause expression changes in noncoding RNAs.
Materials and Methods: MCF-7 and MDA-MB-231 cell lines were grown in a DMEM culture medium supplemented with fetal bovine serum and antibiotics. At exponential growth, cells were exposed to various doses of megavoltage X-rays. 24 and 48 h after irradiation cells were harvested, RNA was extracted and cDNA was synthesized. The expression level of lncRNAs was measured using quantitative real-time PCR.
Results: This study showed that radiation could increase DANCR and TUG1 lncRNAs expression in breast cancer cell lines 24 and 48 h after receiving radiation. Also, the results suggested that after radiation, the expression of DANCR in the radioresistant cell line was higher than the radiosensitive one; in the case of TUG1, it’s unlike DANCR.
Conclusions: The radiation increased the expression of DANCR and TUG1 lncRNAs in breast cancer cell lines because the expression of DANCR in the MDA-MB- 231 was higher than in the MCF-7. In contrast, the expression level of TUG1 in MCF-7 was higher than the MDA-MB-231. Therefore, lncRNAs, DNACR, and TUG1 might play a role in the radioresistance and radiosensitivity of breast cancer, respectively.