Increased fatty acyl saturation of phosphatidylinositol phosphates in prostate cancer progression

Phosphoinositides (PIPs) participate in many cellular processes, including cancer progression; however, the metabolic features of PIPs associated with prostate cancer (PCa) are unknown. We investigated PIPs profiles in PTEN-deficient prostate cancer cell lines, human prostate tissues obtained from patients with PCa and benign prostate hyperplasia (BPH) specimens using mass spectrometry. In immortalized normal human prostate PNT1B cells, PTEN deficiency increased phosphatidylinositol tris-phosphate (PIP₃) and decreased phosphatidylinositol mono- and bis-phosphate (PIP₁ and PIP₂), consistent with PTEN's functional role as a PI(3,4,5)P₃ 3-phosphatase. In human prostate tissues, levels of total (sum of all acyl variants) phosphatidylinositol (PI) and PIP₁ in PCa were significantly higher than in BPH, whereas PIP₂ and PIP₃ contents were significantly lower than in BPH. PCa patients had significantly higher proportion of PI, PIP_1, and PIP₂ with 0-2 double bonds in acyl chains than BPH patients. In subgroup analyses based on PCa aggressiveness, mean total levels of PI with 0-2 double bonds in acyl chains were significantly higher in patients with pathological stage T3 than in those with pathological stage T2. These data indicate that alteration of PIPs level and the saturation of acyl chains may be associated with the development and aggressiveness of prostate cancer, although it is unknown whether this alteration is causative.