De novo lipogenesis prolongs the lifespan and supports the immunosuppressive phenotype of neutrophils in HCC metastasis.
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ABSTRACT:
SUBMITTER: Hu C
PROVIDER: S-EPMC9293710 | biostudies-literature | 2022 Sep
REPOSITORIES: biostudies-literature
Publications
<i>De novo</i> lipogenesis prolongs the lifespan and supports the immunosuppressive phenotype of neutrophils in HCC metastasis.
Hu Chaojie C Chang E E Yu Rucui R Wu Zhiwei Z Li Qing Q Xie Qiang Q Wang Hua H Yin Shi S
Genes & diseases 20220110 5
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Project description:Background and aimsMetabolic dysfunction-associated steatotic liver disease (MASLD) is the most common cause of hepatocellular carcinoma (HCC). In this study, we combine metabolomic and gene expression analysis to compare HCC tissues with non-tumoural tissues (NTT).MethodsA non-targeted metabolomic strategy LC-MS was applied to 52 pairs of human MASLD-HCC and NTT separated into 2 groups according to fibrosis severity F0F1-F2 versus F3F4. The expression of genes related to de Novo lipogenesis (DNL) and fatty acid oxidation (FAO) has been analysed by quantitative RT-PCR and/or interrogation of RNA-seq datasets in 259 pairs of tissues (MASLD-HCC vs. VIRUS-HCC).ResultsMetabolomic analysis revealed that acylcarnitines were the main discriminating metabolites according to fibrosis severity when we compared MASLD-HCC-F0F1-F2 versus NTT and MASLD-HCC-F3F4 versus NTT. Based on these metabolomic data, the analysis of a panel of 15 selected genes related to DNL and FAO indicated that there is no difference between the 2 groups of MASLD-HCC. In contrast the same comparative gene analysis according to the aetiology of HCC: MASLD-HCC versus VIRUS-HCC showed that both aetiologies shared the same upregulation of genes involved in DNL. However, five genes involved in FAO (HADHA, CRAT, CPT1, CPT2 and PPARA) are upregulated exclusively in MASLD-HCC. This result indicates that FAO and DNL pathways are simultaneously activated in MASLD-HCC in contrast to VIRUS-HCC.ConclusionsThese results suggest that, the involvement of adaptive metabolic pathways is different depending on the aetiology of HCC. Moreover, the dogma that simultaneous activation of FAO and DNL is incompatible in cancer would not apply to MASLD-HCC.
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Project description:Cancer cells exhibit elevated lipid synthesis. In breast and other cancer types, genes involved in lipid production are highly upregulated, but the mechanisms that control their expression remain poorly understood. Using integrated transcriptomic, lipidomic, and molecular studies, here we report that DAXX is a regulator of oncogenic lipogenesis. DAXX depletion attenuates, while its overexpression enhances, lipogenic gene expression, lipogenesis, and tumor growth. Mechanistically, DAXX interacts with SREBP1 and SREBP2 and activates SREBP-mediated transcription. DAXX associates with lipogenic gene promoters through SREBPs. Underscoring the critical roles for the DAXX-SREBP interaction for lipogenesis, SREBP2 knockdown attenuates tumor growth in cells with DAXX overexpression, and DAXX mutants unable to bind SREBP1/2 have weakened activity in promoting lipogenesis and tumor growth. Remarkably, a DAXX mutant deficient of SUMO-binding fails to activate SREBP1/2 and lipogenesis due to impaired SREBP binding and chromatin recruitment and is defective of stimulating tumorigenesis. Hence, DAXX's SUMO-binding activity is critical to oncogenic lipogenesis. Notably, a peptide corresponding to DAXX's C-terminal SUMO-interacting motif (SIM2) is cell-membrane permeable, disrupts the DAXX-SREBP1/2 interactions, and inhibits lipogenesis and tumor growth. These results establish DAXX as a regulator of lipogenesis and a potential therapeutic target for cancer therapy.
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Project description:Patients with nonalcoholic fatty liver disease (NAFLD) are reported to have low growth hormone (GH) production and/or hepatic GH resistance. GH replacement can resolve the fatty liver condition in diet-induced obese rodents and in GH-deficient patients. However, it remains to be determined whether this inhibitory action of GH is due to direct regulation of hepatic lipid metabolism. Therefore, an adult-onset, hepatocyte-specific, GH receptor (GHR) knockdown (aLivGHRkd) mouse was developed to model hepatic GH resistance in humans that may occur after sexual maturation. Just 7 days after aLivGHRkd, hepatic de novo lipogenesis (DNL) was increased in male and female chow-fed mice, compared with GHR-intact littermate controls. However, hepatosteatosis developed only in male and ovariectomized female aLivGHRkd mice. The increase in DNL observed in aLivGHRkd mice was not associated with hyperactivation of the pathway by which insulin is classically considered to regulate DNL. However, glucokinase mRNA and protein levels as well as fructose-2,6-bisphosphate levels were increased in aLivGHRkd mice, suggesting that enhanced glycolysis drives DNL in the GH-resistant liver. These results demonstrate that hepatic GH actions normally serve to inhibit DNL, where loss of this inhibitory signal may explain, in part, the inappropriate increase in hepatic DNL observed in NAFLD patients.
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