pH low insertion peptides conjugated to fatty acid metabolism inhibitors to prevent cancer cell proliferation

In this study, our objective was to develop pHLIP-fatty acid metabolism inhibitor conjugates to prevent cancer cell proliferation. Initially, we conjugated inhibitors to two pHLIPs, a reported and a designed sequence. Through intrinsic tryptophan fluorescence and circular dichroism measurements, we assessed the conjugates' potency to insert and structure in a pH-dependent manner into large unilamellar vesicles of different lipidic compositions. We observed variations in structuration and insertion based on the peptide sequence, cargo lipophilicity, and vesicle composition. Finally, we evaluated the ability of the conjugates to prevent tumor growth in 2D acidic cancer cells and 3D cancer cell models. Under DHA ferroptotic inducer conditions, the conjugates successfully inhibited cancer cell proliferation. Additionally, fluorescent variants of the conjugates stained the acidic compartments of tumor spheroids, indicating a pH preference for cells with extracellular acidification.