Quantitative Phosphoproteomics and Acetylomics of Safranal Anticancer Effects in Triple-Negative Breast Cancer Cells

Safranal, as an aroma in saffron, is one of the cytotoxic
compounds
in saffron that causes cell death in triple-negative breast cancer
cells. Our recent research reported the anti-cancer effects of safranal,
which further demonstrated its impact on protein translation, mitochondrial
dysfunction, and DNA fragmentation. To better understand the underlying
mechanisms, we identified acetylated and phosphorylated peptides in
safranal-treated cancer cells. We conducted a comprehensive phosphoproteomics
and acetylomics analysis of safranal-treated MDA-MB-231 cells by using
a combination of TMT labeling and enrichment methods including titanium
dioxide and immunoprecipitation. We provide a wide range of phosphoproteome
regulation in different signaling pathways that are disrupted by safranal
treatment. Safranal influences the phosphorylation level on proteins
involved in DNA replication and repair, translation, and EGFR activation/accumulation,
which can lead the cells into apoptosis. Safranal causes DNA damage
which is followed by the activation of cell cycle checkpoints for
DNA repair. Over time, checkpoints and DNA repair are inhibited and
cells are under a mitotic catastrophe. Moreover, safranal prevents
repair by the hypo-acetylation of H4 and facilitates the transcription
of proapoptotic genes by hyper-acetylation of H3, which push the cells
to the brink of death.