Abstract
Cancer stem cells (CSCs) are regarded as essential targets to overcome tumor progression and therapeutic resistance; however, practical targeting approaches are limited. Here, we identify testis-specific Y-like protein 5 (TSPYL5) as a CSC-associated factor that promotes stemness and epithelial-to-mesenchymal transition in therapy-resistant non-small cell lung cancer (NSCLC) cells. Aberrantly activated PI3K/AKT pathway in therapy-resistant NSCLC cells promotes TSPYL5 phosphorylation at threonine-120 (pT120), which inhibits ubiquitination and stabilizes TSPYL5. TSPYL5 pT120 also supports SUMOylation, which leads to its nuclear translocation and functions as a transcriptional repressor of PTEN. Nuclear TSPYL5 also activates the transcription of CSC-associated genes, ALDH1 and CD44. Collectively, TSPYL5 pT120 maintains persistent CSC-like characteristics via transcriptional activation of CSC-associated genes and via a positive-feedback loop between the AKT/TSPYL5/PTEN and PTEN/PI3K/AKT signaling pathways. However, inhibition of TSPYL5 pT120 can block aberrant AKT/TSPYL5/PTEN cyclic signaling and cancer stemness. Our study suggests TSPYL5 as a novel target for cancer therapy.
A positive feedback loop of IL-17B-IL-17RB activates ERK/β-catenin to promote lung cancer metastasis