Phenotypic plasticity and metabolic dysregulation are two well characterised hallmarks of cancer1, yet how these two phenomena interact to drive tumour progression remains less well known. A central question is whether changes in metabolism are simply by-products of the transcriptional changes associated with tumourigenesis, or, whether alterations in metabolism can also drive transcriptional variation and cell plasticity. Using novel machine learning techniques, we defined five cell states or ‘archetypes’, describing plasticity at the single cell level. Intriguingly, two archetypes had highly divergent metabolism, one relying on glycolysis, whilst another was driven by oxidative phosphorylation. Association between stem cells (including cancer stem cells that exhibit enhanced plasticity) and increased levels of glycolysis is well characterised, therefore we investigated two glycolytic targets, GLUT3 (glucose transporter-3) and lactylation.
GLUT3: Bioinformatic analysis revealed GLUT3 to be associated with the cancer stem cell state. GLUT3 is a high-affinity glucose transporter typically expressed in neurons, however upregulation has also been reported in some cancers2. Functional knockdown assays were subsequently performed to identify the function of GLUT3 in a cancer stem cell population, where knockdown resulted in a significant decrease in proliferation, glucose uptake as well as tumoursphere formation, suggesting reduced self-renewal capacity. Future work will analyse the impact GLUT3 inhibition in vivo on tumour progression and metastasis.
Lactylation: In recent years, a novel, lactate derived post-translational modification, lactylation has been discovered. Due to a growing body of literature supporting the notion that lactylation may drive transcriptional changes3,4, we hypothesised that the differential production of lactate in our archetype data may correlate with varied levels of lactylation and thus, changes in gene expression that underlie cell state changes. Excitingly, our initial data demonstrates increased levels of lactylation in cancer stem cells compared to non-cancer stem cells. Inhibition of lactylation resulted in a significant decrease in tumoursphere formation and reduced expression of CD44, a canonical stem cell marker. Ongoing analysis will further characterise the role of lactylation in maintaining the cancer stem cell state. Overall, these data validate that inhibition of metabolic targets could limit cancer cell plasticity, potentially leading to reduced tumour growth, metastasis and therapy resistance.