Food supplement hinders prostate cancer cell growth in low-risk patients
MedWire News: Australian researchers have developed a dietary supplement which interrupts growth-promoting signaling pathways in prostate cancer cells.
The supplement is designed for men on active surveillance programs for low-risk prostate cancer and contains ingredients commonly consumed in Mediterranean and East-Asian countries where prostate cancer incidence is lower than in Western societies, explains the team.
“Developing a chemoprevention strategy to retard cancer progression in these otherwise healthy men is of great importance and deserves urgent attention,” write Qihan Dong, from Royal Prince Alfred Hospital in Sydney, and co-authors.
The effects of the supplement, which includes extracts of fresh olive leaf, grape seed and skin, citrus skin, and green tea in a blueberry and raspberry juice, were examined in vitro and in vivo using the human prostate cancer cell lines, LNCaP and PC3.
The researchers observed a dose–dependent reduction in in vitro LNCaP and PC3 growth of 83% and 93%, respectively, after 72 hours of treatment with 0.64% concentration of supplement.
The team ruled out the possibility that the supplement indiscriminately targets highly proliferative cells by treating non-cancerous prostate epithelial cells with 0.32% supplement. Cell growth decreased by 38% at this concentration, but there was no further reduction at a dose of 0.64%.
A significant decrease in viability of LNCaP and PC3 was also seen after 72 hours of treatment with 0.60% supplement concentration and greater. A [3H] thymidine incorporation assay also showed decreased cell proliferation at the same concentration.
When researchers injected mice with PC3 cells, they recorded a 25% reduction in tumor growth after 10% supplement was added to the mice’s drinking water for 2 weeks, compared with control animals fed plain tap water.
Dong and team also treated LNCaP with varying concentrations of supplement for 72 hours and observed a reduction in concentrations of proteins involved in the androgen receptor (AR), phospho-protein kinase B (Akt), and phospho-cytosolic phospholipase A2α (cPLA2α) signaling pathways necessary for cell survival and proliferation. Concurrently, the amount of prostate-specific antigen released into the culture media was reduced.
They conclude that simultaneous inhibition of these three pathways “could provide optimal inhibition of cancer progression and attests to the potential of [the supplement] in retarding the progression of low-grade, early-stage prostate cancer in men managed by active surveillance.”
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By Sarah Guy