Background
Long non-coding RNA H19 (lncRNA H19) has been implicated in tumorigenesis and metastasis of breast cancer through regulating epithelial to mesenchymal transition (EMT); however, the underlying mechanisms remain elusive.
Conclusions
Our findings provide insight into a novel mechanism of lncRNA H19 in tumorigenesis and metastases of breast cancer and demonstrate H19/p53/TNFAIP8 axis as a promising therapeutic target for breast cancer, especially for TNBC.
Methods
LncRNA H19 and TNFAIP8 were identified by qRT-PCR and western blotting. CCK-8 assay, clone formation assay, transwell assay, and flow cytometry assay were performed to determine cell proliferation, migration, invasion and cell cycle of breast cancer respectively. Western blotting and immunohistochemistry (IHC) were utilized to evaluate the protein expression levels of p53, TNFAIP8, and marker proteins of EMT cascades in vivo. Dual luciferase reporter assay and RNA pull down assay were conducted to evaluate the interactions of lncRNA H19, p53 and TNFAIP8.
Results
The expression of lncRNA H19 and TNFAIP8 was up-regulated in breast cancer tissues and cell lines, especially in triple-negative breast cancer (TNBC). Functionally, knockdown of lncRNA H19 or TNFAIP8 coused the capacities of cell proliferation, migration, and invasion were suppressed, and cell cycle arrest was induced, as well as that the EMT markers were expressed abnormal. Mechanistically, lncRNA H19 antagonized p53 and increased expression of its target gene TNFAIP8 to promote EMT process. Furthermore, silencing of lncRNA H19 or TNFAIP8 also could inhibit tumorigenesis and lymph node metastases of MDA-MB-231 cells in xenograft nude mouse models. Conclusions: Our findings provide insight into a novel mechanism of lncRNA H19 in tumorigenesis and metastases of breast cancer and demonstrate H19/p53/TNFAIP8 axis as a promising therapeutic target for breast cancer, especially for TNBC.