BRAF-Inhibitor-Induced Metabolic Alterations in A375 Melanoma Cells

Abstract

Acquired drug tolerance has been a major challenge in cancer therapy. Recent evidence has revealed the existence of slow-cycling persister cells that survive drug treatments and give rise to multi-drug-tolerant mutants in cancer. Cells in this dynamic persister state can escape drug treatment by undergoing various epigenetic changes, which may result in a transient metabolic rewiring. In this study, with the use of untargeted metabolomics and phenotype microarrays, we characterize the metabolic profiles of melanoma persister cells mediated by treatment with vemurafenib, a BRAF inhibitor. Our findings demonstrate that metabolites associated with phospholipid synthesis, pyrimidine, and one-carbon metabolism and branched-chain amino acid metabolism are significantly altered in vemurafenib persister cells when compared to the bulk cancer population. Our data also show that vemurafenib persisters have higher lactic acid consumption rates than control cells, further validating the existence of a unique metabolic reprogramming in these drug-tolerant cells. Determining the metabolic mechanisms underlying persister cell survival and maintenance will facilitate the development of novel treatment strategies that target persisters and enhance cancer therapy.

Metabolism-dependent secondary effect of anti-MAPK cancer therapy on DNA repair

“…Accordingly, persister cells (i.e. non-genetically modified cells that survive anti-MAPK therapy) (i) have a lower intracellular concentration of Glu and Asp as compared to the initial cell population (Figure 5B ), in agreement with the OXPHOS pathway re-activation reported in these cells and (ii) express a low level of gene products involved in DNA metabolism (Figure 5D – F ), in agreement with their reported slow growing rate ( 46–48 , 81–86 ).…”

“…Accordingly, growth medium depletion of Gln induced Glu- and Asp-intracellular concentration decrease, while Glu- and/or Asp-depletion did not result in their intracellular concentration decrease (Figure 4C and Supplementary Figure S4b ), probably because Glu and Asp can be generated from Gln from the growth medium ( 45 , 76 ). Importantly, the use of Gln, Glu and Asp in the oxidative phosphorylation (OXPHOS) pathway, which produces energy from the complete degradation of their carbon skeleton, is reactivated by MAPKi ( 46–51 , 73 ). This may explain the observed Glu- and Asp-intracellular concentration decrease in MAPKi-exposed cells (Figures 4A and 5B ).…”

“…Accordingly, cancers cells are often addicted to certain amino acids, such as Gln in melanoma cells ( 37 , 41 , 44 , 45 ). The link between cell metabolism and gene expression–dependent cell phenotypes could have consequences in cancer cells exposed to anti-cancer agents, such as MAPK-inhibitors (MAPKi) used to treat melanoma, since these molecules modify the cancer cell metabolism ( 46–51 ). In other words, anticancer therapies may impact cellular phenotypes because of metabolic-dependent effects on gene product expression levels.…”

Role of Rho/MRTF in Aggressive Vemurafenib-Resistant Murine Melanomas and Immune Checkpoint Upregulation

“…We sought to determine whether activation of the MRTF pathway contributes to Vem–resistance. Using CCG-257081, an MRTF-pathway inhibitor (MRTFi) acting downstream of ROCK [ 24 , 25 ] we tested effects of the compound on measures of Rho/MRTF signaling and cell sensitivity to Vem. Treating YUMM1.7_R and YUMMER_R with 10 µM of CCG-257081 for 24 h significantly reduced actin-stress fibers ( Figure 4 a–d).…”

Metabolism-dependent secondary effect of anti-MAPK cancer therapy on DNA repair

“…Accordingly, cancers cells are often addicted to certain amino acids, such as Gln in melanoma cells 37,41,44,45 . The link between cell metabolism and gene expression-dependent cell phenotypes could have consequences in cancer cells exposed to anti-cancer agents, such as MAPKinhibitors (MAPKi) used to treat melanoma, since these molecules modify the cancer cell metabolism [46][47][48][49][50][51] . In other words, anticancer therapies may impact cellular phenotypes because of metabolicdependent effects on gene product expression levels.…”