Carbonic anhydrase IX (CA9), a pH-regulating transmembrane protein, is highly expressed in solid tumors, and particularly in clear cell renal cell carcinoma (ccRCC). The catalytic mechanisms of CA9 are well defined, but its roles in mediating cell migration/invasion and survival in ccRCC remain to be determined. Here, we confirmed that the mRNA expression of CA9 in ccRCC was significantly higher than that in para-carcinoma tissues from analysis of the datasets in The Cancer Genome Atlas. CA9 knockdown upregulated oxidative phosphorylation-associated proteins and increased mitochondrial biogenesis, resulting in the reversal of the Warburg phenotype and the inhibition of cell growth. Our study revealed that CA9 knockdown upregulated mitochondrial arginase 2 (ARG2), leading to the accumulation of putrescine, which suppressed ccRCC proliferation. Surfaceomics analysis revealed that CA9 knockdown downregulated proteins associated with extracellular matrix (ECM)—receptor interaction and cell adhesion, resulting in decreased cell migration. CA9 silencing also downregulated amino acid transporters, leading to reduced cellular amino acids. Collectively, our data show that CA9 knockdown suppresses proliferation via metabolic reprogramming and reduced cell migration, reaffirming that CA9 is a potential therapeutic target for ccRCC treatment.

Understanding the tissue distribution of phospholipids and glycerolipids in animal models enables promoting the pharmacokinetic study of drugs and related PK predictions. The measurement of lipid compositions in animal models, usually mice and rats, without a standardized approach hindered the accuracy of PBPK investigation. In this work, high resolution mass spectrometry was applied to profile the tissue distribution of phospholipids and glycerolipids in 12 organs/tissues of mice and rats. Using this method, not only the amounts of phospholipids and glycerolipids in each organ/tissue but also the fatty acid compositions were acquired. In order to explore the interspecies specificity of lipid distribution in different organs/tissues, three animal species including CD1 mice, NMRI mice, and Wister rats were used in this systematic study. Globally, more organ specificity was observed. It was found that the brain is the organ containing the most abundant phosphatidylserine lipids (PSs) in all three animal models, leading to brain tissues having the most concentrated acidic phospholipids. Diverse fatty acid compositions in each lipid class were clearly revealed. Certain tissues/organs also had a specific selection of unique fatty acid compositions, for example, unreferenced FA(18 : 2) in the brain. It turned out that the access of free fatty acids affects the incorporation of acyl chain in phospholipids and glycerolipids. In the analysis, ether lipids were also profiled with the observation of dominant ePEs in brain tissues. However, little interspecies difference was found for fatty acid constituents and tissues distribution of phospholipids and glycerolipids.