LINC01503 promotes the cell proliferation, migration and invasion of triple-negative breast cancer as a ceRNA to elevate SPNS2 expression by sponging miR-335-5p.

OBJECTIVE

Triple-negative breast cancer (TNBC) is a common cancer with high aggressiveness and high mortality in women. Recently, a plenty of studies have indicated that long non-coding RNAs (lncRNAs) exert the crucial function in human cancers, TNBC is included. The carcinogenicity of lncRNA long intergenic non-protein coding RNA 1503 (LINC01503) has been confirmed in several cancers, nevertheless, its function in TNBC still unclear. Therefore, our study aimed to reveal the underlying mechanism of LINC01503 in TNBC.

METHODS

In our study, RT-qPCR was performed to detect the expression of LINC01503 in TNBC cells. The proliferative, invasive, migratory and apoptotic abilities of TNBC cells were detected by functional assay such as CCK-8, clone formation, EdU staining, transwell, and flow cytometry. RIP, RNA pull down, and luciferase assay revealed interactions between LINC01503, miR-335-5p, and sphingolipid transporter protein 2 (SPNS2). Finally, rescue experiments were performed to validate the previous results.

RESULTS

LINC01503 expression was singularly high in TNBC cells. LINC01503 knockdown could restrain cell proliferation, invasion and migration, but accelerated cell apoptosis in TNBC. What's more, miR-335-5p could be sponged by LINC01503 in TNBC. We also found that overexpressed miR-335-5p could inhibit cell proliferation, migration and invasion and facilitates cell apoptosis. Moreover, SPNS2 was the target gene of miR-335-5p and it functioned as an oncogene in TNBC cells. Finally, we found that overexpressed SPNS2 or inhibited miR-335-5p could reverse the suppressive function of silencing LINC01503 on TNBC progression.

CONCLUSION

LINC01503 could facilitate cell proliferation, migration and invasion of TNBC by sponging miR-335-5p to elevate SPNS2 expression.