Background: Cancer cells have an increased demand for amino acids and require transport even of non-essential amino acids to support their increased proliferation rate. Besides their major role as protein synthesis precursors, the two proteinogenic sulfur-containing amino acids, methionine and cysteine, play specific biological functions. In humans, methionine is essential for cell growth and development and may act as a precursor for cysteine synthesis. Cysteine is a precursor for the biosynthesis of glutathione, the major scavenger for reactive oxygen species. Methodology and Principal Findings: We study the effect of K-ras oncogene activation in NIH3T3 mouse fibroblasts on transport and metabolism of cysteine and methionine. We show that cysteine limitation and deprivation cause apoptotic cell death (cytotoxic effect) in both normal and K-ras-transformed fibroblasts, due to accumulation of reactive oxygen species and a decrease in reduced glutathione. Anti-oxidants glutathione and MitoTEMPO inhibit apoptosis, but only cysteine-containing glutathione partially rescues the cell growth defect induced by limiting cysteine. Methionine limitation and deprivation has a cytostatic effect on mouse fibroblasts, unaffected by glutathione. K-ras-transformed cells-but not their parental NIH3T3 - are extremely sensitive to methionine limitation. This fragility correlates with decreased expression of the Slc6a15 gene - encoding the nutrient transporter SBAT1, known to exhibit a strong preference for methionine - and decreased methionine uptake. Conclusions and Significance: Overall, limitation of sulfur-containing amino acids results in a more dramatic perturbation of the oxido-reductive balance in K-ras-transformed cells compared to NIH3T3 cells. Growth defects induced by cysteine limitation in mouse fibroblasts are largely-though not exclusively-due to cysteine utilization in the synthesis of glutathione, mouse fibroblasts requiring an exogenous cysteine source for protein synthesis. Therapeutic regimens of cancer involving modulation of methionine metabolism could be more effective in cells with limited methionine transport capability.

DE SANCTIS, G., Spinelli, M., Vanoni, M., Sacco, E. (2016). K-ras activation induces differential sensitivity to sulfur amino acid limitation and deprivation and to oxidative and anti-oxidative stress in mouse fibroblasts. PLOS ONE, 11(9) [10.1371/journal.pone.0163790].

K-ras activation induces differential sensitivity to sulfur amino acid limitation and deprivation and to oxidative and anti-oxidative stress in mouse fibroblasts

DE SANCTIS, GAIA;SPINELLI, MICHELA;VANONI, MARCO ERCOLE;SACCO, ELENA
2016

Abstract

Background: Cancer cells have an increased demand for amino acids and require transport even of non-essential amino acids to support their increased proliferation rate. Besides their major role as protein synthesis precursors, the two proteinogenic sulfur-containing amino acids, methionine and cysteine, play specific biological functions. In humans, methionine is essential for cell growth and development and may act as a precursor for cysteine synthesis. Cysteine is a precursor for the biosynthesis of glutathione, the major scavenger for reactive oxygen species. Methodology and Principal Findings: We study the effect of K-ras oncogene activation in NIH3T3 mouse fibroblasts on transport and metabolism of cysteine and methionine. We show that cysteine limitation and deprivation cause apoptotic cell death (cytotoxic effect) in both normal and K-ras-transformed fibroblasts, due to accumulation of reactive oxygen species and a decrease in reduced glutathione. Anti-oxidants glutathione and MitoTEMPO inhibit apoptosis, but only cysteine-containing glutathione partially rescues the cell growth defect induced by limiting cysteine. Methionine limitation and deprivation has a cytostatic effect on mouse fibroblasts, unaffected by glutathione. K-ras-transformed cells-but not their parental NIH3T3 - are extremely sensitive to methionine limitation. This fragility correlates with decreased expression of the Slc6a15 gene - encoding the nutrient transporter SBAT1, known to exhibit a strong preference for methionine - and decreased methionine uptake. Conclusions and Significance: Overall, limitation of sulfur-containing amino acids results in a more dramatic perturbation of the oxido-reductive balance in K-ras-transformed cells compared to NIH3T3 cells. Growth defects induced by cysteine limitation in mouse fibroblasts are largely-though not exclusively-due to cysteine utilization in the synthesis of glutathione, mouse fibroblasts requiring an exogenous cysteine source for protein synthesis. Therapeutic regimens of cancer involving modulation of methionine metabolism could be more effective in cells with limited methionine transport capability.
Articolo in rivista - Articolo scientifico
Methionine; Cysteine; Glutathione; anti-oxidant, K-Ras oncogene, transformed fibroblast, cell proliferation, cell metabolism, apoptosis
English
DE SANCTIS, G., Spinelli, M., Vanoni, M., Sacco, E. (2016). K-ras activation induces differential sensitivity to sulfur amino acid limitation and deprivation and to oxidative and anti-oxidative stress in mouse fibroblasts. PLOS ONE, 11(9) [10.1371/journal.pone.0163790].
File in questo prodotto:
File Dimensione Formato  
journal.pone.0163790.PDF

accesso aperto

Descrizione: Main text
Dimensione 4.32 MB
Formato Adobe PDF
4.32 MB Adobe PDF Visualizza/Apri
Supplementary information.pone0163790.pdf

accesso aperto

Dimensione 1.2 MB
Formato Adobe PDF
1.2 MB Adobe PDF Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/140848
Citazioni
  • Scopus 5
  • ???jsp.display-item.citation.isi??? 5
Social impact