BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) has been associated with the host dysmetabolism of branched-chain amino acids (BCAAs), however, the implications for the role of BCAA metabolism in PDAC development or progression are not clear. The mitochondrial catabolism of valine, leucine, and isoleucine is a multistep process leading to the production of short-chain R-CoA species. They can be subsequently exported from mitochondria as short-chain carnitines (SC-CARs), utilized in anabolic pathways, or released from the cells. METHODS: We examined the specificities of BCAA catabolism and cellular adaptation strategies to BCAA starvation in PDAC cells in vitro. We used metabolomics and lipidomics to quantify major metabolic changes in response to BCAA withdrawal. Using confocal microscopy and flow cytometry we quantified the fluorescence of BODIPY probe and the level of lipid droplets (LDs). We used BODIPY-conjugated palmitate to evaluate transport of fatty acids (FAs) into mitochondria. Also, we have developed a protocol for quantification of SC-CARs, BCAA-derived metabolites. RESULTS: Using metabolic profiling, we found that BCAA starvation leads to massive triglyceride (TG) synthesis and LD accumulation. This was associated with the suppression of activated FA transport into the mitochondrial matrix. The suppression of FA import into mitochondria was rescued with the inhibitor of the acetyl-CoA carboxylase (ACC) and the activator of AMP kinase (AMPK), which both regulate carnitine palmitoyltransferase 1A (CPT1) activation status. CONCLUSIONS: Our data suggest that BCAA catabolism is required for the import of long chain carnitines (LC-CARs) into mitochondria, whereas the disruption of this link results in the redirection of activated FAs into TG synthesis and its deposition into LDs. We propose that this mechanism protects cells against mitochondrial overload with LC-CARs and it might be part of the universal reaction to amino acid perturbations during cancer growth, regulating FA handling and storage.

• Publikační typ
• časopisecké články MeSH

Karcinom pankreatu (KP), jehož incidence je v západních zemích na vzestupu, patří mezi nádory s nejhorší prognózou. KP je již v časných stadiích provázen nádorovou kachexií, systémovým postižením, které vede k vyčerpání hostitelových substrátových rezerv. Cílem projektu je identifikovat klíčové metabolické dráhy nádoru a tukové tkáně asociované s nádorovou kachexií. Pacienti s KP budou charakterizováni (antropometrie, inzulínová citlivost a sekrece, substrátová utilizace, zánětlivé parametry) s cílem komplexní metabolické diagnostiky nádorové kachexie. Primární kultury z nádoru budou podrobeny metabolomické analýze, zejména ve vztahu k metabolizmu glutaminu a aminokyselin s větveným řetězcem, a interferenci jejich degradačních drah. Ve vzorku peripankreatického tuku bude analyzována lipolytická a sekreční aktivita. U diferencovaných adipocytů bude sledována schopnost inzulín-senzitizujících látek omezit uvolňování lipidů vyvolané nádorovým médiem. Výsledky umožní popsat substrátový cross-talk hostitele a nádoru a identifikovat její potenciální léčebné cíle kachexie u KP.; Pancreatic cancer (PC), whose incidence is increasing in the Western countries, ranks among tumours with the worst prognosis. PC is associated with early development of cancer cachexia, a systemic condition leading to the depletion of host substrate reserves. The project aims to identify key metabolic pathways of the tumour and adipose tissue related to cancer cachexia. Patients with PC will be characterized (anthropometry, insulin sensitivity and secretion, substrate utilization, inflammatory parameters) to describe complex metabolic phenotype. Primary cultures of the tumour will be subjected to metabolomics analyses, specifically related to glutamine and branched chain amino acid metabolism and interference of their degradation pathways. Peripancreatic fat will be analysed for its lipolytic and secretory activity. In differentiated adipocytes, the ability of insulin sensitizing drugs to ameliorate lipolysis induced by tumour medium will be assessed. Results will enable to describe host-tumour substrate cross-talk and to identify potential treatment targets of PC induced cachexia.

• Klíčová slova
• Karcinom pankreatu, Pancreatic cancer, inzulínová rezistence, insulin resistance, glutaminolýza, glutaminolysis, nádorová kachexie, cancer cachexia, Lipolýza, BCAA, Lipolysis, BCAA,

• NLK Publikační typ
• závěrečné zprávy o řešení grantu AZV MZ ČR