Riccardin D Exerts Its Antitumor Activity by Inducing DNA Damage in PC-3 Prostate Cancer Cells In Vitro and In Vivo

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Riccardin D (RD) was previously shown to induce apoptosis by targeting Topoisomerase II.
• Prostate cancer remains a significant health concern, necessitating novel therapeutic strategies.

Purpose of the Study:

• To elucidate the mechanism by which Riccardin D (RD) induces cell death and inhibits prostate cancer growth.
• To investigate RD's effects on DNA damage, cell cycle progression, and DNA repair pathways.

Main Methods:

• PC-3 prostate cancer cells were treated with RD to assess cell cycle arrest, DNA damage (γH2AX foci, micronuclei, Comet assay), and signaling pathway activation (ATM/ATR).
• DNA repair mechanisms (BRCA1, HR, NHEJ) and protein expression (Ku70/86) were evaluated.
• Microarray analysis was performed on RD-treated cells, and xenograft mouse models were used to assess in vivo efficacy.

Main Results:

• RD induced G2/M phase cell cycle arrest and significant DNA damage in PC-3 cells.
• Activation of ATM/Chk2 and ATR/Chk1 pathways was observed, and blocking these pathways partially restored cell proliferation.
• RD inactivated BRCA1, suppressed homologous recombination (HR) and non-homologous end joining (NHEJ) repair, and downregulated Ku70/86 expression and DNA-binding activity.
• RD administration reduced tumor growth in xenograft mice, correlating with altered gene expression in DNA damage/repair and apoptosis pathways.

Conclusions:

• Riccardin D (RD) acts as a DNA-damaging agent in prostate cancer by inducing cell cycle arrest and inhibiting critical DNA repair pathways.
• RD demonstrates therapeutic potential for prostate cancer by reducing tumor growth through mechanisms involving DNA damage and apoptosis induction.