FOXA1-induced LINC00621 promotes lung adenocarcinoma progression via activating the TGF-β signaling pathway

Lung adenocarcinoma (LUAD) is highly malignant and associated with poor prognoses in patients worldwide. There has been widespread recognition that lncRNAs are tightly linked to LUAD tumorigenesis and development. Here, we identified that the LINC00621 level was increased in LUAD tissues and concerned with the poor prognoses in LUAD patients.

Bioinformatical analysis and RT-qPCR determined the level of LINC00621 in LUAD tissues and cell lines. The admeasurement of the proliferation, migration, and invasion abilities of LUAD cells was utilized in the CCK8 and Transwell formulas. Luciferase reporter assay was used to corroborate the downstream target genes of LINC00621. The phosphorylated SMAD3 protein was tested by Western blotting assay. The impression of LINC00621 knockdown on LUAD tumor growth and metastasis put into effect by murine models. ChIP-qPCR assay was carried out to verify the transcriptional regulation by FOXA1 on LINC00621.

In vitro, the knockdown of LINC00621 significantly reduced the proliferative, migrating, and invasive abilities, the same was true for tumorigenesis and metastasis in vivo. MiR-34a-5p as a straight target of LINC00621 was ascertained, and LUAD patients with inferior miR-34a-5p levels had undesirable prognoses. Furthermore, TGFBR1 is an immediate and functional connection site of miR-34a-5p. Collectively, LINC00621 can sponge miR-34a-5p and upregulate TGFBR1 levels, which further sensitized TGF-β signaling pathway. Finally, it was revealed that FOXA1 transcriptionally upregulated LINC00621.

This study uncovered that FOXA1-induced LINC00621 promotes LUAD progression via the miR-34a-5p/TGFBR1/TGF-β axis, and is one novel therapeutic target that may be used in LUAD treatment.