Figure 1.
The inhibition of SCD1 activity blocks cell cycle progression and induces programmed cell death in cancer cells.
In H460 lung cancer cells treated with 1µM CVT-11127 (CVT) or DMSO for 48h, in presence or absence of 100µM oleic (Ole), the distribution of cells in cell cycle phases was determined by fluorocytometry (A), levels of cyclin D1, CDK6 and β-actin were assessed by Western blot (B), and the rate of apoptosis was determined by the levels of fragmented [3H]thymidine-labeled DNA (C). *, p<0.05 or less vs. vehicle-treated cells; **, p<0.05 or less vs CVT-treated cells, by Student’s t test.
Figure 2.
Impaired cell proliferation of cancer cells with a blockade in SCD1 activity is restored by exogenous cis- and trans-MUFA.
A, H460 lung cancer cells were treated with 1 µM CVT-11127 (CVT) or DMSO for 48 h in presence or absence of 100 µM cis-MUFA palmitoleic acid (Pol), oleic acid (Ole) or cis-vaccenic acid; and cell proliferation was determined by Crystal violet staining. Proliferation was similarly assessed in H460 cells that were treated with 1 µM CVT-11127 (CVT) or DMSO for 48 h in presence or absence of 100 µM SFA myristic (Myr), palmitic (Pal), heptadecanoic (Hep), or stearic (Ste) acids (B), or 250 µM Pal, plus or minus 250 µM Ole or elaidic (Ela) (C). Groups of DMSO- and CVT-treated cells were incubated with 2 µg/mL tunicamycin in presence or absence of 100 µM oleic acid for 48 h and cell growth was determined (D). *, p<0.05 or less, vs DMSO; **, p<0.05 or less vs fatty acid-treated control, by Student's t test.
Figure 3.
Inhibition of SCD activity with CVT-11127 impairs the proliferation of H460 cancer cells but not normal human fibroblasts.
Cell growth was determined in AG01518 normal human fibroblasts (A) in presence of 1 and 2 µM CVT-11127 in 10%FBS DMEM or vehicle for 96 h. H460 cells (B) were treated with 1 µM CVT-11127 or vehicle for 96 h. Cell proliferation rate was assessed by Crystal violet staining. *, p<0.05 or less, vs DMSO; by Student's t test.
Figure 4.
Oleic acid is unable to fully reverse the low proliferation rate of SCD1-deficient when de novo lipid synthesis is blocked.
H460 lung cancer cells were treated with 1 µM CVT-11127 (CVT), 10 µM CP-640186 or both in presence or absence of 100 µM palmitic acid (Pal) or oleic acid (Ole) (A), and cell proliferation was assessed after 48 h. Distribution of cells in cell cycle phases was determined by fluorocytometry in cells incubated with CP-640186 plus or minus 100 µM oleic acid and (B). Cancer cell proliferation was also determined upon treatment with 1 µM CVT-11127 (CVT), 20 µM CP-640186, or both in presence or absence of 100 µM palmitic acid (Pal) or oleic acid (Ole) (C), and in cells treated for 48 h with 1 µM CVT-11127, 25-hydroxycholesterol or both, plus or minus 100 µM oleic acid (D). In all experiments, control cells received equivalent volumes of DMSO vehicle. *, p<0.05 or less compared to DMSO; **, p<0.05 or less compared to CVT-treated control, by Student's t test.
Figure 5.
Effect of exogenous fatty acids on the levels of lipids in SCD1-deficient cells.
H460 lung cancer cells were treated with 1 µM CVT-11127 (CVT) for 48 h in presence or absence of 100 µM oleic acid (Ole). Total cell lipids were extracted, separated by TLC and stained with iodine vapors (A). Relative levels of, triacylglycerols (B), cholesterolesters (C), and phospholipids (D), were determined by densitometric scanning. *, p<0.05 or less, vs DMSO; **, p<0.05 or less vs CVT-treated control, by Student's t test.