Cancer stem cell-like cells-derived exosomal CDKN2B-AS1 stabilizes CDKN2B to promote the growth and metastasis of thyroid cancer via TGF-β1/Smad2/3 signaling

Abstract

As CDKN2B-AS1 is demonstrated to exert promotive effects on thyroid cancer (TC), this research aims to investigate the role of cancer stem cell-like cells (CSCs)-derived exosomal CDKN2B-AS1 in TC and the underlying regulatory mechanism. Specifically, CDKN2B expression and the correlation of CDKN2B with CDKN2B-AS1 in TC were determined via bioinformatics analysis and further verified by qRT-PCR. After transfection or co-culture with CSCs-derived exosomes, viability, migration, and invasion of TPC-1 and SW579 cells were evaluated by CCK-8, wound healing, and transwell assays, respectively. The uptake of exosomes by TC cells was detected by PKH67 labeling. In vivo tumor formation and metastasis models were established. Tumor volume and weight were calculated. Metastasis loci in lung tissues were observed by hematoxylin-eosin staining. The expression levels of CDKN2B-AS1, CDKN2B, and epithelial-mesenchymal transition- and TGF-β1/Smad2/3 signaling-related factors were detected by qRT-PCR or Western blot. Concretely, CDKN2B and CDKN2B-AS1 were highly expressed in TC, and there was a positive correlation between the two. In addition, CDKN2B-AS1 promoted the translation and stability of CDKN2B. Furthermore, CDKN2B-AS1 was highly expressed in CSCs and CSCs-derived exosomes which could be absorbed by TC cells. CDKN2B silencing inhibited viability, migration, invasion, protein levels of CDKN2B, N-cadherin and Vimentin, and TGF-β1/Smad2/3 signaling, while promoting E-cadherin expression in TC cells. CSCs-derived exosomal CDKN2B-AS1 did oppositely and reversed the effects of CDKN2B silencing on TC cells. CDKN2B silencing impeded tumor growth and metastasis in TC mice, while TGF-β1 performed inversely and impaired the effects of CDKN2B silencing. Collectively, CSCs-derived exosomal CDKN2B-AS1 stabilizes CDKN2B to promote growth and metastasis of TC via TGF-β1/Smad2/3 signaling.