A chalcone-syringaldehyde hybrid inhibits triple-negative breast cancer cell proliferation and migration by inhibiting CKAP2-mediated FAK and STAT3 phosphorylation

Background: Although triple-negative breast cancer (TNBC) accounts for only 15% of breast cancer cases, it is associated with a high relapse rate and poor outcome after standard treatment. Currently, the effective drugs and treatment strategies for TNBC remain limited, and thus, developing effective treatments for TNBC is pressing. Several studies have demonstrated that both chalcone and syringaldehyde have anticancer effect, but their potential anti-TNBC bioactivity are still unknown.

Purpose: The present study aimed to synthesize a chalcone-syringaldehyde hybrid (CSH1) and explore its potential anti-TNBC effects and the underlying molecular mechanism.

Methods: Cell cytotoxicity was determined by 3-(4,5-dimethythiazol)-2,5-diphenyltetrazolium bromide (MTT). The activity of cell proliferation was measured by colony formation assay and 5-ethynyl-2'-deoxyuridine (EdU) staining assay. Cell cycle distribution and cell apoptosis were determined by fluorescence-activated cell sorter (FACS). The situation of DNA damage was observed using fluorescence microscopy. The ability of cell-matrix adhesion, migration and invasion was detected using cell adhesion assay and transwell assay. Transcriptome sequencing was performed to find out the changed genes. Levels of various signaling proteins were assessed by western blotting.

Results: CSH1 treatment triggered DNA damage and inhibited DNA replication, cell cycle arrest, and cell apoptosis via suppressing signal transducer and activator of transcription 3 (STAT3) phosphorylation. Whole genome RNA-seq analysis suggested that 4% of changed genes were correlated to DNA damage and repair, and nearly 18% of changed genes were functionally related to cell adhesion and migration. Experimental evidence indicated that CSH1 treatment significantly affected the distribution of focal adhesion kinase (FAK) and its phosphorylation, resulting in cell-matrix-adhesion reduction and migration inhibition of TNBC cells. Further mechanistic studies indicated that CSH1 inhibited TNBC cell proliferation, adhesion, and migration by inhibiting cytoskeleton-associated protein 2 (CKAP2)-mediated FAK and STAT3 phosphorylation signaling.

Conclusion: These results suggest that CKAP2-mediated FAK and STAT3 phosphorylation signaling is a valuable target for TNBC treatment, and these findings also reveal the potential of CSH1 as a prospective TNBC drug.