Effects of the lncRNA NBR2 on the proliferation and autophagy of breast cancer cells under starvation conditions

Abstract An increasing number of studies indicate that long noncoding RNAs (lncRNAs) play important roles in tumour proliferation, migration and other vital processes and are expected to become novel biomarkers for early cancer screening. The expression of the lncRNA NBR2 (adjacent breast cancer suppressor BRCA1) has been found to decrease in several cancer types. However, it is still unknown whether the lncRNA NBR2 is involved in breast cancer and autophagy. According to the Kaplan–Meier plotter survival curve analysis, the survival rate of the group with high lncRNA-NBR2 expression was higher than that of the group with low lncRNA-NBR2 expression. The suppression of cancer cell proliferation, invasion and migration by the lncRNA NBR2 has been demonstrated, suggesting that this lncRNA is involved in the development and progression of cancer. Our subsequent study revealed that the lncRNA NBR2 inhibited autophagy in breast cancer cells, and that starvation conditions enhanced this inhibitory effect. Moreover, this lncRNA changed the proliferation ability of breast cancer cells by affecting protective autophagy. The aim of this study was to investigate the link between starvation and lncRNAs by evaluating changes in autophagy-related proteins, cell proliferation and other biological processes. Together, these studies provide strategies for the early screening of breast cancer and suggest that starvation therapy can be used as a new approach for the treatment of cancer.