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

Abstract

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 non-coding 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.

A review on the role of gamma-butyrobetaine hydroxylase 1 antisense RNA 1 in the carcinogenesis and tumor progression

“…The migration and invasion ability of tumor cells decreases after BBOX1-AS1 knockdown in multiple tumors. BBOX1-AS1 also inhibits ferroptosis [ 44 ] and enhances stemness [ 42 ] in esophageal carcinoma, promotes autophagy and sorafenib resistance in hepatocellular carcinoma [ 46 ]. Knockdown of BBOX1-AS1 resulted in cell cycle arrest in lung squamous cell carcinoma [ 38 ] and hepatocellular carcinoma [ 47 ].…”

“…For instance, in NPC, two different ceRNA mechanisms involving BBOX1-AS1 have been identified: BBOX1-AS1 can promote the proliferation, migration, and invasion of NPC cells by targeting miR-3940-3p/KPNA2 axis [ 37 ] and miR-204-5p/MUC4 axis [ 36 ]. Similarly, in esophageal carcinoma [ 41 , 42 , 44 , 45 ], BBOX1-AS1 interacts with three miRNAs (miR-506-5p, miR-513a-3p, miR-361-3p) and subsequently upregulates the expression of four target genes (EIF5A, SLC7A11, COL5A1, COL1A1), promoting tumor cell growth, migration, invasion, and accelerating the progression and metastasis of esophageal cancer.…”

“…This extended stability results in higher levels of the corresponding proteins encoded by these mRNAs, thereby impacting various cellular processes. For example, in esophageal squamous cell carcinoma, BBOX1-AS1 targets miR-506-5p/EIF5A to maintain PTCH1 mRNA stability, leading to increased PTCH1 expression and enhanced cancer development [ 42 ]. Similarly, in cervical cancer, BBOX1-AS1 can interact with HuR, enhancing the mRNA stability of HOXC6, subsequently upregulating the HOXC6 protein expression, and promoting cancer cell proliferation, migration, and invasion abilities [ 53 ].…”

“…Accumulating evidence suggests that lncRNAs play a significant role in regulating multiple signaling pathways, offering insights into the development of targeted therapies [ 58 – 63 ]. Currently, BBOX1-AS1 has been confirmed to participate in the regulation of the Hedgehog signaling pathway [ 42 ]. And the genes regulated by BBOX1-AS1 are also associated with other cancer-related signaling pathways, including the Wnt/β-catenin signaling pathway [ 43 ] and MELK/FAK signaling [ 39 ].…”

“…Dysregulation of this pathway also has been linked to the development and progression of various cancers [ 68 , 69 ]. BBOX1-AS1 has been shown to upregulate PTCH1 by sponging miR-506-5p, which in turn upregulates EIF5A, stabilizing PTCH1 mRNA and ultimately activating the Hedgehog signaling pathway [ 42 ]. By modulating this critical signaling pathway, BBOX1-AS1 can impact ESCC cell proliferation and stemness, both crucial processes involved in cancer development [ 70 – 72 ].…”