Vascular invasion is considered as the critical risk factor of hepatocellular carcinoma (HCC). To reveal the molecular mechanisms underlying macrovascular invasion (MaVI) in HCC, we performed an iTRAQ based proteomic study to identify notably dysregulated proteins from eight HCC patients with differential vascular invasion and further confirmed them in the other 53 HCC patients. Forty-seven proteins were found significantly down-regulated in HCC with MaVI. More importantly, 30 of them were not changed in HCC without MaVI. Gene ontology analysis of these 47 proteins shows the top three enriched biological processes are urea cycle, gluconeogenesis, and arginine biosynthetic process. We validated nine remarkably dysregulated candidates in HCC patients with MaVI by Western blot including eight down-regulated proteins (CPS1, ASS1, ASL, ARG1, BHMT, DMGDH, Annexin A6, and CES1) and one up-regulated protein (CKAP4). Furthermore, dysregulation of CPS1, ASL, and ARG1, key enzymes involved in urea cycle, together with Annexin A6 and CES1, major proteins in regulating cholesterol homeostasis and fatty acid ester metabolism, was verified using immunohistochemical staining. The significant down-regulation of urea cycle generates clinically relevant proteomic signature in HCC patients with macrovascular invasion, which may provide possible insights into the molecular mechanisms of metastasis and new therapeutic targets of HCC.

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Tuberous sclerosis complex (TSC) is a genetic disease characterized by seizures, mental deficiency, and abnormalities of the skin, brain, kidney, heart, and lungs. TSC is inherited in an autosomal dominant manner and is caused by variations in either the TSC1 or TSC2 gene. TSC-related epilepsy (TRE) is the most prevalent and challenging clinical feature of TSC, and more than half of the patients have refractory epilepsy. In clinical practice, we found several patients of intractable epilepsy caused by TSC1 truncating mutations. To study the changes of protein expression in the brain, three cases of diseased brain tissue with TSC1 truncating mutation resected in intractable epilepsy operations and three cases of control brain tissue resected in craniocerebral trauma operations were collected to perform protein spectrum detection, and then the data-independent acquisition (DIA) workflow was used to analyze differentially expressed proteins. As a result, there were 55 up-and 55 down-regulated proteins found in the damaged brain tissue with TSC1 mutation compared to the control. Further bioinformatics analysis revealed that the differentially expressed proteins were mainly concentrated in the synaptic membrane between the patients with TSC and the control. Additionally, TSC1 truncating mutations may affect the pathway of amino acid metabolism. Our study provides a new idea to explore the brain damage mechanism caused by TSC1 mutations.