1-deoxysphingolipid synthesis compromises anchorage-independent growth and plasma membrane endocytosis in cancer cells

ABSTRACT: Serine palmitoyltransferase (SPT) predominantly incorporates serine and fatty acyl-CoAs into diverse sphingolipids that serve as structural components of membranes and signaling molecules within or amongst cells. However, SPT also uses alanine as a substrate in the contexts of low serine availability, alanine accumulation, or diseasecausing mutations in hereditary sensory neuropathy type I (HSAN1), resulting in the synthesis and accumulation of 1-deoxysphingolipids. These species promote cytotoxicity in neurons and impact diverse cellular phenotypes, including suppression of anchorage-independent cancer cell growth. While altered serine and alanine can promote 1-deoxysphingolipid synthesis, they impact numerous other metabolic pathways important for cancer cells. Here we combined isotope tracing, quantitative metabolomics, and functional studies to better understand the mechanistic drivers of 1- deoxysphingolipid toxicity in cancer cells. Both alanine treatment and SPTLC1 C133W expression induce 1-deoxy(dihydro)ceramide synthesis and accumulation but fail to broadly impact intermediary metabolism, abundances of other lipids, or growth of adherent cells. However, spheroid culture and soft agar colony formation were compromised when endogenous 1-deoxysphingolipid synthesis was induced via SPTLC1 C133W expression. Consistent with these impacts on anchorageindependent cell growth, we observed that 1-deoxysphingolipid synthesis reduced plasma membrane endocytosis. These results highlight a potential role for SPT promiscuity in linking altered amino acid metabolism to plasma membrane endocytosis.

ORGANISM(S): Human Homo Sapiens

TISSUE(S): Cultured Cells

SUBMITTER: Thekla Cordes  

PROVIDER: ST002274 | MetabolomicsWorkbench | Wed Aug 31 00:00:00 BST 2022

REPOSITORIES: MetabolomicsWorkbench