LncRNA APOC1P1-3 Promoting Anoikis-resistance of Breast Cancer Cells

Abstract Background: Anoikis resistance plays a critical role in the tumor metastasis by allowing survival of cancer cells in the systemic circulation. We previously showed that long non-coding RNAs APOC1P1-3 (lncRNA APOC1P1-3) inhibits breast cancer cell apoptosis. However, its role in the anoikis resistance remains unclear. Methods: We induced anoikis resistance in two breast cancer cell lines (MCF-7 and MDA-MB-231) under anchorage-independent culture condition and studied the effects of lncRNA APOC1P1-3 on the apoptosis. The Dual-Luciferase activity assay were used to whether miRNA-188-3P can specifically bind to lncRNA APOC1P1-3. We further explored the role of APOC1P1-3 in the lung metastasis by injecting MDA-MB-231 and MDA-MB-231-APOC1P1-3-knock-down cells in the female BALB/c nude mice.Results: We found that it suppressed early apoptosis of these cells by gain or loss of their function, respectively. We further explored its mechanism related to anoikis resistance, and found this molecule promoted the resistance via activating Caspase 3, 8, 9 and PARP. Moreover, it was specifically binding to the target miRNA-188-3p to block its inhibition of Bcl-2 (an anti-apoptosis protein). These findings suggest that lncRNA APOC1P1-3 plays an important role in the development of breast cancer metastasis via anoikis resistance. Conclusions: This study demonstrates that lncRNA APOC1P1-3 can promote the anoikis resistance of breast cancer cells and specifically bind to miRNA-188-3p acting as a “sponge” to block the inhibition of anti-apoptotic protein Bcl-2.