A Circular Network of Coregulated Sphingolipids Dictates Lung Cancer Growth and Progression

Sphingolipid metabolism is one of the top dysregulated pathways in NSCLC. However, the molecular control of sphingolipid metabolic reprogramming in cancer progression remains unknown. Here, we first provide clinical evidence that expression of sphingolipid metabolic enzymes, B3GNT5 and GAL3ST1, but not the others, is most significantly associated with patient prognosis, whilst sphingolipidomics analysis of NSCLC patient sera identifies their metabolites, neolacto-series glycosphingolipid and sulfatide, as biomarkers that outperformed current clinical biomarkers for staging patients. Further network analysis of the sphingolipidomes reveals a circular network of coregulated sphingolipids, indicating that the neolacto-series glycosphingolipid/sulfatide balance functions as a checkpoint to determine sphingolipid metabolic reprograming during patient progression. Importantly, sphingolipidomics analysis of B3GNT5/GAL3ST1 genetically perturbed NSCLC cell lines confirms their key regulatory role in sphingolipid metabolism, while B3GNT5 and GAL3ST1 expression has an opposite role on tumorigenesis in vitro and in vivo. Overall, our results provide new insights whereby B3GNT5 and GAL3ST1 differentially regulate sphingolipid metabolism in lung cancer growth and progression. Funding Statement: This work was supported by the Natural Science Foundation of China (81920108028, 81872142); Guangzhou Science and Technology Program (201904020008); Young Teacher Foundation of Sun Yat-sen University (18ykzd07); Guangdong Science and Technology Department (2020B1212060018, 2019A1515011802, 2020A1515011280, 2020A0505100029); China Postdoctoral Science Foundation (2019M650226, 2019M650227). Declaration of Interests: No potential conflicts of interest were disclosed. Ethics Approval Statement: Serum samples were collected from healthy individuals and NSCLC patients (age-matched and body-mass index –matched) with informed consent, and the research program and all the related procedures were approved by the Ethics Committee of Sun Yat-sen Memorial Hospital (Guangzhou, China) and stored according to standard operating procedures for Good Clinical Laboratory Practice standards. All animal procedures were approved by the Institutional Animal Care and Use Committee (IACUC) of Sun Yat-Sen University.