Breast cancer (BC) is one of the most common and severe malignant tumors worldwide. Currently, the prevalence of BC has surpassed that of lung cancer. Triple-negative breast cancer (TNBC) is a special subtype of breast cancer, charactered by poor prognosis, strong invasion, high recurrence rate, and low survival rate, etc. Currently, radiotherapy plays an adjuvant role in the treatment of TNBC and is being investigated in the neoadjuvant setting. Due to the radioresistance, clinical application of radiotherapy in TNBC patients remains challenging. How to improve the radiosensitivity is a hot topic in recent years. With the rapid development of whole-genome and transcriptome sequencing, increasing evidence suggests that long chain non-coding RNA (lncRNA) and circular RNA (circRNA) can play a significant function in regulating the radiosensitivity in TNBC. In this article, research progress in the role of lncRNA and circRNA in the radiosensitivity of TNBC was reviewed, aiming to provide a theoretical basis for elevating the clinical efficacy of radiotherapy in TNBC.

Objective To investigate the effect of downregulated activating transcription factor 3 ( ATF3) expression on proliferation of adrenocortical carcinoma cells and its mechanisms. Methods Immunohistochemistry and Western blotting were used to detect the expression of ATF3 in human adrenocortical tumor tissues and cells. Adrenocortical carcinoma cells, Sw-13, and NCI-H259R cells, were transfected with siATF3 using lipidosome 2000, and expression of ATF3 mRNA was determined using RT-PCR; expression of ATF3, cleaved caspase 3, caspase 3, cleaved PARP, and PARP proteins were detected using Western blotting; cell growth inhibition rate and apoptosis rate were monitored using MTT and AnnexinV-FITC/PI, respectively. Sw-13 and NCI-H259R cells were treated with NVP-BEZ235, Perifosine, BKM120, IWP-2, PP2, KN93, Everolimus respectively followed by detected expression of ATF3 mRNA by realtime PCR. The effect of ATF3 on cell proliferation after inhibition of related signaling pathways were detected by MTT. Results The ATF3 in human adrenocortical gland tumor tissues and cells showed high expression. The levels of ATF3 mRNA and protein in Sw-13 and NCI-F259R cells transfected with siATF3 were significantly reduced. Compared with the negative control group ( NC siRNA), siATF3 transfection significantly inhibited the proliferation of Sw-13 and NCI-F259R cells ( P＜0. 05 ), and increased the apoptosis rate ( P＜0.05). Western blotting shown that the levels of cleaved caspase 3 and cleaved PARP protein in siATF3 transfected cells increased significantly; and realtime PCR results indicated that the expression of ATF3 mRNA was dramatically inhibited by PP2, KN93, and IWP-2 in NCI-F259R cells compared with control group ( DMSO ); but ATF3 significantly promoted the proliferation activity of NCI-F259R cells which treated by PP2, KN93, and IWP-2 signaling inhibitors. Conclusion High expression of ATF3 is existed in adrenocortical carcinoma cells. Downregulated ATF3 expression may inhibit cell proliferation and activate apoptosis pathway, resulting in apoptosis in Sw-13 and NCI-F259R cells, this mechanism of action is related to activating Wnt/β-catenin, CaMKI, and SRC pathway.