Riboflavin-PLGA nanoparticles enhance the effectiveness of the pyruvate carboxylase inhibitor ZY-444 in targeting lipogenesis in colon and breast cancer

Targeting cancer metabolism has become a promising strategy for cancer treatment. Pyruvate carboxylase (PC) is an anaplerotic enzyme that replenishes tricarboxylic acid cycle intermediates. PC is overexpressed in several types of human cancers, especially in aggressive cancers, including breast and colon cancer, where it promotes growth, survival, and metastasis. Recently, N⁴-((5-(4-(benzyloxy)phenyl)-2-thiophenyl)methyl)-N²-isobutyl-2,4-pyrimidinediamine (ZY-444) has been reported to possess anti-cancer activity by inhibiting PC activity in breast cancer. In this study, we expanded the potential of ZY-444 to highly aggressive colon cancer, HT-29 and HCT116, and further enhanced its efficacy using nanodelivery systems. The results reveal that ZY-444 not only inhibits the clonogenic growth of these colon cancer cells but also downregulates the expression of several key lipogenic enzymes, accompanied by a marked reduction in triglyceride and cholesterol levels. To improve its efficacy, ZY-444 was encapsulated in poly(lactic-co-glycolic acid) (PLGA) nanoparticles with a surface coated with riboflavin (Rf)-functionalized chitosan (CSRf), a ligand known to target Rf transporters. The ZY-444-loaded PLGA nanoparticles exhibited a spherical morphology with an approximate size of 300 nm and a positive zeta potential, demonstrating their suitability for drug delivery applications. Compared with the free compound, ZY-444 encapsulated in nanoparticles demonstrated markedly enhanced efficacy being 11-, 14-, and 19-fold more potent in inhibiting the clonogenic growth of HT-29, HCT116, and MDA-MB-231 cells, respectively. In addition, the encapsulated form was over 10 times more effective at suppressing the migration and invasion of HCT116 and MDA-MB-231 cells. Encapsulated ZY-444 also more strongly inhibited the expression of lipogenic enzymes, further reinforcing its effect on lipid metabolism. Collectively, these findings underscore the potential of ZY-444-loaded PLGA nanoparticles as a promising drug delivery system for suppressing colon and breast cancer through targeted inhibition of the de novo lipogenesis pathway.