GAS5 Suppresses Cell Proliferation, Migration, and Invasion via the miR-455-5p/CDKN1B Axis in Cutaneous Squamous Cell Carcinoma

Cutaneous squamous cell carcinoma (cSCC) is a common dermatologic malignancy characterized by aberrant proliferation of keratinocytes. Molecular targeted therapy appears to be a promising approach for advanced cSCC. Long noncoding RNA growth arrest specific 5 (GAS5) was reported to be downregulated in skin cancer tissues. This study aimed to explore the functions and underlying mechanism of GAS5 in the development of cSCC. GAS5 expression in cSCC cells was examined by reverse transcription quantitative polymerase chain reaction. The localization of GAS5 in cSCC cells was detected by subcellular fractionation assays. The viability, proliferation, apoptosis, migration, and invasion of cSCC cells after indicated transfection were examined by Cell Counting Kit-8 assays, colony formation assays, TdT-mediated dUTP Nick-End Labeling assays, wound healing assays, and Transwell assays. Western blot analysis was performed to quantify the protein level of messenger RNA cyclin-dependent kinase inhibitor 1B (CDKN1B). In addition, luciferase reporter assays, RNA pulldown assays and RNA immunoprecipitation assays were carried out to explore the binding relation between miR-455-5p and GAS5 (or CDKN1B). GAS5 was lowly expressed in cSCC cells and was primarily located in cytoplasm. GAS5 overexpression inhibited cell viability, proliferation, migration, and invasion while enhancing cell apoptosis. In addition, GAS5 interacted with miR-455-5p to positively regulate CDKN1B expression. CDKN1B is a direct target of miR-455-5p. Furthermore, CDKN1B knockdown rescued the suppressive effect of GAS5 overexpression on malignant behaviors of cSCC cells. GAS5 suppresses cSCC cell proliferation, migration, and invasion by targeting the miR-455-5p/CDKN1B axis. This study provides novel insight into the role of GAS5 in cSCC development.