SPHK1 and cancer: Results showed that compared with BEAS-2B, treatment with PF-543 led to substantial declines in cell viability, represented by H460, H226 and H1299 cells, suggesting that cancer cells were more sensitive to SPHK1-inhibition than normal lung epithelial cells, with a half maximal inhibitory concentration (IC50) of 20.45 μM in H460 cells, 16.80 μM in H226 cells and 26.55 μM in H1299 cells, respectively (Figure 3A).