SphK1 promotes tumor cell migration and invasion in colorectal cancer

Colorectal cancer (CRC) is one of the most common cancers worldwide. Sphingosine kinase 1 (SphK1), which phosphorylates sphingosine to sphingosine-1-phosphate (S1P), is overexpressed in various types of cancers and may act as an oncogene in tumorigenesis. However, little is known about the role of SphK1 in CRC patients. We studied the expression of SphK1 in 85 cases of CRC tissues by immunohistochemistry, qRT-PCR, and western blot. We also evaluated the effect of SphK1 on cell proliferation and invasion by MTT and transwell invasion assay. SphK1 is overexpressed in CRC tissues and cell lines, and upregulation of SphK1 correlated significantly with the following parameters: lymph node metastasis, liver metastasis, and advanced TNM stage. SphK1 knockdown results in inhibition of cancer cell proliferation. Inhibition of CRC cell migration and invasion is also evident through reversal of EMT by increases in E-cadherin expression and decreases in vimentin expression. In conclusion, SphK1 is associated with the proliferation and invasiveness of CRC cells and the SphK1 gene may contribute to a novel therapeutic approach against CRC.