LncRNA PITPNA-AS1/miR-223-3p/PTN axis regulates malignant progression and stemness in lung squamous cell carcinoma

Background: Long noncoding RNAs (lncRNAs) are a kind of molecule that cannot code proteins, and their expression is dysregulated in diversified cancers. LncRNA PITPNA-AS1 has been shown to act as a tumor promoter in a variety of malignancies, but its function and regulatory mechanisms in lung squamous cell carcinoma (LUSC) are yet unknown.

Methods: The mRNA and protein expression of genes were examined by RT-qPCR, western blot, and IHC assay. The cell proliferation, migration, invasion, and stemness were detected through CCK-8, colony formation, Transwell and spheroid formation assays. The CD44⁺ and CD166⁺ -positive cells were detected through flow cytometry. The binding ability among genes through luciferase reporter and RNA pull-down assays. The tumor growth was detected through in vivo nude mice assay.

Results: The lncRNA PITPNA-AS1 had increased expression in LUSC and was linked to a poor prognosis. In LUSC, PITPNA-AS1 also enhanced cell proliferation, migration, invasion, and stemness. This mechanistic investigation showed that PITPNA-AS1 absorbed miR-223-3p and that miR-223-3p targeted PTN. MiR-223-3p inhibition or PTN overexpression might reverse the inhibitory effects of PITPNA-AS1 suppression on LUSC progression, as demonstrated by rescue experiments. In addition, the PITPNA-AS1/miR-223-3p/PTN axis accelerated tumor development in vivo.

Conclusions: It is the first time we investigated the potential role and ceRNA regulatory mechanism of PITPNA-AS1 in LUSC. The data disclosed that PITPNA-AS1 upregulated PTN through sponging miR-223-3p to enhance the onset and progression of LUSC. These findings suggested the ceRNA axis may serve as a promising therapeutic biomarker for LUSC patients.