Vaccinium myrtillus L. extract and its native polyphenol-recombined mixture have anti-proliferative and pro-apoptotic effects on human prostate cancer cell lines

Vaccinium myrtillus berry extract (VME) and a recombined standard mixture (RSM) of its main native phenolic compounds were investigated for cell growth inhibition and pro-apoptotic activity on hormone-dependent (LNCaP) and hormone-independent (PC3 and DU-145) prostate cancer (PCa) cell lines. Normal prostate epithelial cells (PrEC) were also studied in comparison. VME hindered anchorage-dependent PCa cell proliferation in a dose-dependent manner, that is, at 1/800 (v/v) dilution for LNCaP and PC3, and 1/100 (v/v) dilution for DU-145 (corresponding to 14.15 and 113.2 μg cyanidin-3-O-glucoside equivalents per ml of culture medium), respectively. VME had a growth inhibitory effect towards PrEC at the same dilution of DU-145 cells although the IC50 values indicated that PrEC are more resistant than PCa cell lines. VME also reduced the anchorage-independent growth of PCa cells. The study of the apoptotic profile (i.e., non-apoptotic, early apoptotic, late apoptotic and necrotic cells) evidenced that the apoptotic rate (early+late) was statistically higher in all three cell lines exposed to VME compared to control. Anchorage-dependent and anchorage-independent growth inhibition of RSM was very similar to that displayed by VME. Moreover, RSM exerted its growth inhibitory effect also under hypoxia, the latter representing a biological condition known to sustain PCa proliferation and aggressiveness.