Mistletoe Extracts Inhibit Progressive Growth of Prostate Cancer Cells

Area of Science:

• Oncology
• Pharmacology
• Complementary and Alternative Medicine

Background:

• Prostate cancer (PCa) remains challenging, especially castrate-resistant forms.
• Mistletoe extracts are used as complementary medicine, but their mechanisms in PCa are unclear.
• Investigating mistletoe's effects on PCa cell lines is crucial for understanding its therapeutic potential.

Purpose of the Study:

• To evaluate the in vitro effects of mistletoe extracts from four host trees on prostate cancer cell lines.
• To explore the impact of mistletoe on PCa cell growth, proliferation, apoptosis, and cell cycle.
• To investigate the role of CD44 and integrins in mistletoe's anti-cancer activity.

Main Methods:

• Utilized PC3, DU145, and LNCaP prostate cancer cell lines.
• Assessed cell growth (MTT), proliferation (BrdU), clonogenicity, apoptosis, and cell cycle.
• Analyzed cell-cycle proteins (CDKs, cyclins), CD44 variants, and integrins (α and β).
• Performed siRNA knockdown studies for integrin functional relevance.

Main Results:

• All mistletoe extracts demonstrated dose-dependent inhibition of cell growth, proliferation, and clonogenicity.
• Populi and Salicis extracts induced G2/M cell-cycle arrest and increased apoptosis.
• Mistletoe extracts modulated CDK1, cyclin A, CD44 expression, and diminished specific integrins (α5, α6).
• Integrin knockdown (α5, α6) inhibited DU145 cell growth.

Conclusions:

• Mistletoe extracts effectively inhibit prostate cancer cell growth and proliferation in vitro.
• Specific extracts (Populi, Salicis) induce apoptosis and cell-cycle arrest.
• Mistletoe's effects involve modulation of cell cycle proteins, CD44, and integrins.
• Mistletoe warrants further investigation as an adjunct therapy for prostate cancer in preclinical models.