A, Basal DGKα levels were evaluated by immunoblot in normal human cell lines and various cancer cell lines, with α-tubulin shown as loading control. Cell toxicity was assessed by cell counts/trypan blue in B, A-375 (melanoma), C, HeLa (cervical cancer), and D, MDA-MB-231 (breast cancer) lines 4 days after DGKα knockdown or treatment with R59022 at 10 µM or DMSO vehicle. E, Dose response curves were generated for astrocytes, fibroblasts, U251, U87, A-375, HeLa, MDA-MB-231, and 0308 (GBM stem cell) cells by cell counts and normalized for DMSO (v:v) at 5, 10, 20, 40, 60, 80, and 100 µM R59022 after 4 days of treatment. (*, P<0.05 and **, P<0.01 Student t test)