Exploring the Anticancer Properties and Mode of Action of Copper(II)‐Furan Acylhydrazone on Human Triple Negative Breast Cancer Cells

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer with limited therapeutic treatments. This study evaluates the anticancer activity and mode of action of the copper(II) complex [Cu(HL¹)(NO₃)H₂O]·H₂O (CuHL¹), derived from (E)-N'-(2-hydroxy-3-methoxybenzylidene)furan-2-carbohydrazide (H₂L¹), against a panel of TNBC cell lines (MDA-MB-231, MDA-MB-468, MDA-MB-157, HCC1806). CuHL¹ exhibits potent cytotoxicity in the low micromolar range (IC₅₀ ≈ 2 µM), surpassing cisplatin by up to 81-fold. In MDA-MB-231 cells, CuHL¹ inhibits colony formation and induced reactive oxygen species (ROS) generation in a concentration-dependent manner. Moreover, CuHL¹ triggers apoptosis as evidenced by Annexin V/PI staining and the modulation of Bax, Bcl-2, caspase-3, and cleaved caspase-3 protein levels. Label-free quantitative proteomics reveal 34 differentially expressed proteins, implicating pathways related to heat shock response, protein folding, lipid metabolism, and cell migration. Notably, CuHL¹ downregulates BCAR3, AJUBA, MPZL1, TP53, FASN, and HMGCS1, suggesting inhibition of prometastatic and lipid biosynthetic processes. Functional assays confirm reduced migratory capacity in MDA-MB-231 cells. These findings position CuHL¹ as a promising candidate for TNBC therapy, meriting further in vivo evaluation.