Metabolic Targeting of ASAH1 in Combination with Carnosine as a Therapeutic Strategy for TNBC.

Triple-negative breast cancer (TNBC) is a highly aggressive breast cancer subtype with limited targeted therapies, leading to higher mortality compared with other breast cancer subtypes. In our previous study we identified N-acyl sphingosine amidohydrolase 1 (ASAH1) to be overexpressed in TNBC cells and demonstrated its role in promoting TNBC growth and progression. ASAH1 is a metabolic enzyme that converts ceramide into sphingosine and free fatty acids, thereby creating a favorable environment for tumor growth. To gain a more comprehensive understanding of the metabolic alterations associated with ASAH1 inhibition, we performed a large-scale metabolomic analysis of TNBC cells expressing ASAH1 shRNAs. Our analysis revealed a significant increase in carnosine levels following ASAH1 inhibition. Subsequent studies demonstrated that exogenous treatment of TNBC cells with carnosine inhibited their growth. Moreover, combining carnosine with ASAH1 inhibitors (carmofur or ceranib-2) resulted in potent synergistic inhibition of TNBC growth. Mechanistically, the combined treatment led to a greater reduction in mitochondrial membrane potential, increased mitochondrial superoxide production and further increased apoptosis. Collectively, these results identify a new metabolism-based combination therapeutic strategy for the effective treatment of TNBC.