LncRNA TSPEAR-AS2 Maintains the Stemness of Gastric Cancer Stem Cells by Regulating the miR-15a-5p/CCND1 Axis

Cancer stem cells (CSCs), a subpopulation of tumor cells endowed with self-renewal capacity, drive cancer initiation and progression. While long non-coding RNAs (lncRNAs) are increasingly recognized as critical regulators of CSC stemness, their specific roles in gastric cancer stem cells (GCSCs) remain poorly understood. This study investigates the functional significance of lncRNA TSPEAR-AS2 in modulating GCSC properties and uncovers its underlying molecular mechanisms. Through integrated whole-transcriptome sequencing, bioinformatics analysis, and validation in 48 paired gastric cancer tissues and adjacent normal tissues, TSPEAR-AS2 was identified as a differentially expressed lncRNA upregulated in both GCSCs and tumor samples. Functional experiments revealed that TSPEAR-AS2 overexpression significantly enhanced GCSC sphere-forming ability, proliferation, cell cycle progression, epithelial-mesenchymal transition (EMT), and expression of stemness markers (CD54, CD44, OCT4, NANOG, and SOX2) while suppressing apoptosis. Conversely, TSPEAR-AS2 knockdown attenuated these malignant phenotypes. In vivo tumorigenicity assays in nude mice further confirmed that TSPEAR-AS2 promotes tumor growth, with overexpression accelerating and knockdown inhibiting tumor formation. Mechanistically, bioinformatics predictions and dual-luciferase reporter assays established TSPEAR-AS2 as a competing endogenous RNA (ceRNA) that sponges miR-15a-5p, thereby derepressing the miR-15a-5p target gene CCND1. Rescue experiments demonstrated that overexpression of miR-15a-5p phenocopied TSPEAR-AS2 knockdown, reducing GCSC stemness, while miR-15a-5p inhibition rescued the effects of TSPEAR-AS2 suppression. Collectively, these findings reveal a novel TSPEAR-AS2/miR-15a-5p/CCND1 regulatory axis that sustains GCSC stemness and tumorigenicity. These results highlight TSPEAR-AS2 as a potential therapeutic target for eradicating gastric cancer stem cells and improving clinical outcomes.