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.