HN1L promotes stem cell-like properties by regulating TGF-beta signaling pathway through targeting FOXP2 in prostate cancer

Dysregulated hematological and neurological expressed 1-like (HN1L) has been implicated in carcinogenesis of difference cancers, including hepatocellular carcinoma and breast cancer. However, the role of HN1L in the progression of prostate cancer (PCA) remains unknown. Therefore, we aimed to investigate the role of HN1L in stemness and progression of PCA. The expression of HN1L in PCA tissues and cells was determined by quantitative reverse-transcription polymerase chain reaction (qRT-PCR), western blot analysis, and/or immunohistochemistry (IHC). CD133(+) cells were sorted from PCA cells using magnetic fluorescence cell sorting technology and were considered as cancer stem cells (CSCs). Sphere formation assays, transwell assays, and animal experiments were conducted to assess cell stemness, migration, invasion, and in vivo tumorigenesis, respectively. The results showed that HN1L expression was higher in PCA tissues and cells as compared with normal tissues and cells, as well as in CD133(+) cells as compared with CD133(-) cells. HN1L knockdown significantly decreased the expression levels of CSC markers including OCT4 (POU class 5 homeobox 1), CD44, and SRY-box transcription factor 2, inhibited cell migration, invasion, and tumorigenesis and decreased the number of tumor spheroids and CD133(+) cell population. Furthermore, we found that HN1L could bind to forkhead box P2 (FOXP2) and positively regulated transforming growth factor-beta (TGF-beta) expression via upregulation of FOXP2. In addition, the overexpression of TGF-beta in HN1L-knockdown PCA cells increased the number of tumor spheroids and CD133(+) cell population, as well as enhanced cell migration and invasion. Collectively, this study demonstrates that HN1L promotes stem cell-like properties and cancer progression by targeting FOXP2 through TGF-beta signaling pathway in PCA.