CSRP2 Influences cell Stemness and Prognosis in Head and Neck Cancer

Purpose: Cysteine-rich protein 2 (CSRP2), as a newly discovered oncogene, is overexpressed in several cancers. However, the specific role of CSRP2 and its potential mechanism remain incompletely understood in head and neck squamous cell carcinoma (HNSCC). Methods The expression of CSRP2 was explored in the Cancer Genome Atlas (TCGA) databases and the results were confirmed by immunohistochemistry tissue microarrays and Western blotting in HNSCC. The effect of CSRP2 on the cancer stemness and epithelial-to-mesenchymal transition (EMT) of HNSCC cells was investigated by sphere formation, wound healing and transwell assays. A series of in vitro and in vivo experiments were conducted to reveal the mechanisms by which CSRP2 modulated cancer stemness and EMT phenotypes in HNSCC. Results CSRP2 expression was markedly higher in HNSCC tissues than in non-tumor tissues, high CSRP2 expression was positively correlated with lymph node metastasis and recurrence. Noticeably, overall survival rate of HNSCC patients with high CSRP2 expression level presented worse prognosis. In addition, elevated CSRP2 expression was observed in several HNSCC cell lines and mouse HNSCC cell lines, and CSRP2 knockdown inhibited the sphere formation and apoptosis. Additionally, wound healing and transwell assay results showed that CSRP2 knockdown inhibited the migration and invasion ability of the HNSCC cells. Furthermore, we found that CSRP2 was closely associated with CSCs markers (CD44, BMI1 and CD133), EMT-transcription factor (Slug), new oncoprotein LAMTOR5, p-S6 Ser235/236 and immune checkpoint (VISTA) using Tgfbr1/Pten conditional knockout mice model and mouse HNSCC cell line-derived xenograft models. Conclusions Our findings demonstrate that elevated expression of CSRP2 indicates poor prognosis and plays a key role in maintaining the cancer cell stemness and EMT features during the progression of HNSCC, suggesting that CSRP2 may serve as a new and valuable therapeutic target for HNSCC.