BBOX1-AS1 Activates Hedgehog Signaling Pathway to Facilitate the Proliferation and Stemness of Esophageal Squamous Cell Carcinoma Cells via miR-506-5p/EIF5A/PTCH1 Axis

Aims and Objective: This study aimed to unveil the specific function of lncRNA BBOX1 antisense RNA 1 (BBOX1-AS1) in ESCC cells and the underlying regulatory mechanism. Background: Esophageal squamous cell carcinoma (ESCC) is a deadly disease. Molecular mechanisms essential to ESCC development and progression require in-depth investigation. Long noncoding RNAs (lncRNAs) have been suggested as crucial effectors in modulating tumor growth. Methods: RT-qPCR and western blot examined the expression of genes and proteins of concern, respectively. Colony formation and EdU assays assessed the changes in cell proliferation. Sphere formation assay also detected the stemness of ESCC cells. Bioinformatics prediction, along with mechanistic assays (FISH, Subcellular fractionation, RNA pull-down, RIP, and luciferase reporter), was conducted to explore the gene interactions and regulatory relationship. Results: BBOX1-AS1 was observed to be aberrantly up-regulated in ESCC tissues and cell lines. BBOX1-AS1 depletion exerted suppressive impacts on ESCC cell proliferation and stemness, while BBOX1-AS1 overexpression led to the opposite consequences. Moreover, BBOX1-AS1 was verified to activate Hedgehog signaling pathway via up-regulating PTCH1, and BBOX1-AS1 could sponge miR-506-5p to up-regulate EIF5A, thus stabilizing PTCH1 mRNA. Rescue experiments indicated that BBOX1-AS1 could affect ESCC cell proliferation and stemness via modulation on PTCH1. Conclusion: To conclude, BBOX1-AS1 activates Hedgehog signaling pathway to facilitate the proliferation and stemness of ESCC cells via miR-506-5p/EIF5A/PTCH1 axis.