Annonaceous acetogenins have been reported to have anti-cancer properties but low viability. In this study, we aimed to investigate the potency of nanodiamonds to be employed as a carrier of annonacin to help increase its viability and inhibit the growth of breast cancer cells.

Collectively, this study demonstrated the effectiveness of nanodiamonds as a carrier of annonacin to inhibit breast cancer cell growth through inhibition of the PI3K/Akt signaling pathway.

The annonacin was coupled with nanodiamond and characterized using UV-Vis spectrophotometer, FTIR, SEM, and PSA, and determined their stability and drug release. A cell growth inhibition assay and cell migration assay was performed using the breast cancer MCF7 and T747D cell lines, and in vivo analysis was performed in rats (Rattus norvegicus). MCF7 and T747D cells were treated with 12.5 μg/mL annonacin coupled with nanodiamonds for 24 and 48 h and further analyzed by MTT, cell migration, and reactive oxygen species (ROS) assays. Twenty-five female rats were divided into five groups. Breast cancer was induced using two intraperitoneal doses of N-nitroso-N-methylurea (NMU) (50 and 30 mg/kg body weight). Annonacin coupled with nanodiamonds was administered by intraperitoneal injection (17.5 mg/kg body weight) for 5 weeks, one injection per 3 days.

Administration of annonacin coupled with nanodiamonds significantly reduced MCF7 cell growth and reactive oxygen species (ROS) levels. The in vivo study showed that administration of annonacin coupled with nanodiamonds significantly reduced PI3KCA levels and increased p53 expression, reduced cancer antigen-15-3 (CA-15-3) levels in serum, increased caspase-3 expression, reduced Ki-67 levels, and reduced the thickness of the mammary ductal epithelium. Conclusions: Collectively, this study demonstrated the effectiveness of nanodiamonds as a carrier of annonacin to inhibit breast cancer cell growth through inhibition of the PI3K/Akt signaling pathway.