Comprehensive proteomics and sialiomics of the anti-proliferative activity of safranal on triple negative MDA-MB-231 breast cancer cell lines

Abstract

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with no efficient treatment. Researchers have indicated the importance of quantitative approaches on proteome and different post-translation modifications studies both in diagnosis and treatment purposes. Sialic acid-containing glycopeptides (the sialiome) is one of these modifications which can be used as a tool in cancer diagnosis or therapeutic strategies since the sialylation is strongly associated with cancer migration and metastasis. Based on our study, safranal, which is a non-toxic compound in orally intakes, exhibits a significant cytotoxic effect on MDA-MB-231 in comparison to normal cells. We conducted a comprehensive proteomics and sialiomics analysis of safranal treated MDA-MB-231 cells by using a combination of TMT labeling and titanium dioxide enrichment of sialylated N-linked glycopeptides to investigate the underlying molecular mechanism behind safranal-induced apoptosis. Safranal has main effect on the inhibition of metabolism and mitochondrial dysfunction. It regulates proteins considered as activator of DNA fragmentation and apoptosis mediators. Moreover, safranal regulates sialylation of glycoproteins involving in cellular adhesion, migration and survival. It suppresses cell survival and metastasis through the alteration of the sialylation level on important signaling receptors. These results highlight the impact of safranal as a potent anticancer compound on TNBCs which also can be strongly used in daily diets. SignificanceIn first step, we evaluated the cell viability of MDA-MB-231 cell lines against the purified saffron components (total crocin, picrocrocin, crocin I and safranal). Safranal was the only compound demonstrated the anti-proliferation effect. In order to obtain an understanding of safranal cytotoxic effect on MDA-MB-231, we designed the three set of treated cell lines in 30 min, 12 h and 24 h time-points in three replicates and a combination of TMT-based labeling quantitative proteomics and titanium dioxide (TiO2)-based enrichment of sialylated N-linked glycopeptides for sialiomics analysis as a strategy to follow the more detailed mechanisms of safranal effect. The results of bioinformatics analysis revealed the multifunction role of safranal on MDA-MB-231 cell lines. Safranal mainly dysregulates mitochondrial function, inhibits metabolism and starts initial signaling of apoptosis which lead to DNA fragmentation. Moreover, safranal caused the majority of down-regulation in sialylation profile in all time-points. Safranal also declines the cell survival, adhesion and migration by dysregulation of the sialylation level in important proteins including integrins, tumor necrosis factor receptor and cell adhesion molecules (CAMs). The results provide a set of therapeutic targets for triple negative breast cancer which can help designing of effective anticancer drugs specially in targeted therapies.