Lysine Deprivation Suppresses Adipogenesis in 3T3-L1 Cells: A Transcriptome Analysis.

Growing evidence proves that amino acid restriction can reverse obesity by reducing adipose tissue mass. Amino acids are not only the building blocks of proteins but also serve as signaling molecules in multiple biological pathways. The study of adipocytes' response to amino acid level changes is crucial. It has been reported that a low concentration of lysine suppresses lipid accumulation and transcription of several adipogenic genes in 3T3-L1 preadipocytes. However, the detailed lysine-deprivation-induced cellular transcriptomic changes and the altered pathways have yet to be fully studied. Here, using 3T3-L1 cells, we performed RNA sequencing on undifferentiated and differentiated cells, and differentiated cells under a lysine-free environment, and the data were subjected to KEGG enrichment. We found that the differentiation process of 3T3-L1 cells to adipocytes required the large-scale upregulation of metabolic pathways, mainly on the mitochondrial TCA cycle, oxidative phosphorylation, and downregulation of the lysosomal pathway. Single amino acid lysine depletion suppressed differentiation dose dependently. It disrupted the metabolism of cellular amino acids, which could be partially reflected in the changes in amino acid levels in the culture medium. It inhibited the mitochondria respiratory chain and upregulated the lysosomal pathway, which are essential for adipocyte differentiation. We also noticed that cellular interleukin 6 (IL6) expression and medium IL6 level were dramatically increased, which was one of the targets for suppressing adipogenesis induced by lysine depletion. Moreover, we showed that the depletion of some essential amino acids such as methionine and cystine could induce similar phenomena. This suggests that individual amino acid deprivation may share some common pathways. This descriptive study dissects the pathways for adipogenesis and how the cellular transcriptome was altered under lysine depletion.

Design, synthesis, antitumor evaluations and molecular modeling studies of novel 3,5-substituted indolin-2-one derivatives.

AIM: To design and synthesize a novel class of antitumor agents, featuring the 3, 5-substituted indolin-2-one framework. METHODS: Based on enzyme binding features of (Z)-SU5402, introducing a beta-pyrrole group at the 3-position of the indolin- 2-one core, a series of novel 3,5-substituted indolin-2-ones were designed and synthesized. Four human carcinoma cell lines of A-431, A-549, MDA-MB-468, and Autosomal Dominant Polycystic Kidney disease were chosen for the cell proliferation assay. RESULTS: Twenty new compounds (1a-t) with E configuration have been designed, synthesized and bioassayed. Their structural features were determined by nuclear magnetic resonance (NMR) spectra, low- and high-resolution mass spectra, and confirmed by X-ray crystallography. Although the enzyme assay showed a weak inhibition effect against the epidermal growth factor receptor, vascular endothelial growth factor receptor, fibroblast growth factor receptor and platelet-derived growth factor receptor tyrosine kinases, the cell-based antitumor activity was promising. Compounds 1 g and 1 h showed higher inhibitory activity toward the A-549 and MDA-MB-468 cell lines with IC(50 ) of 0.065-9.4 micromol/L. CONCLUSION: This study provides a new template for further development of potent antitumor drugs.