Dataset Information

K-Ras Activation Induces Differential Sensitivity to Sulfur Amino Acid Limitation and Deprivation and to Oxidative and Anti-Oxidative Stress in Mouse Fibroblasts.

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.

SUBMITTER: De Sanctis G

PROVIDER: S-EPMC5042513 | biostudies-literature | 2016

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

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 G Spinelli Michela M Vanoni Marco M Sacco Elena E

PloS one 20160929 9

<h4>Background</h4>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 bi ...[more]

PMID: 27685888

Similar Datasets

Project description:BackgroundOncogene activation plays a role in metabolic reprogramming of cancer cells. We have previously shown that K-ras transformed fibroblasts have a stronger dependence on glycolysis and a reduced oxidative phosphorylation ability as compared to their normal counterparts. Another metabolic adaptation of cancer cells, that has long been established, is their propensity to exhibit increased glutamine consumption, although the effects induced by glutamine deprivation on cancer cells are still controversial.Methodology and principal findingsHere, by using nutritional perturbations and molecular physiology, we show that reduction or complete depletion of glutamine availability in K-ras transformed fibroblasts causes a strong decrease of proliferation ability and a slower re-entry of synchronized cells into the cell cycle. The reduced proliferation is accompanied by sustained expression of cyclin D and E, abortive S phase entrance and is dependent on Ras signalling deregulation, since it is rescued by expression of a dominant negative guanine nucleotide exchange factor. The growth potential of transformed cells as well as the ability to execute the G(1) to S transition is restored by adding the four deoxyribonucleotides, indicating that the arrest of proliferation of K-ras transformed cells induced by glutamine depletion is largely due to a reduced supply of DNA in the presence of signalling pathways promoting G(1) to S transition.Conclusions and significanceOur results suggest that the differential effects of glutamine and glucose on cell viability are not a property of the transformed phenotype per se, but rather depend on the specific pathway being activated in transformation. For instance, myc-overexpressing cells have been reported to die under glutamine depletion and not under glucose shortage, while the opposite holds for ras-transformed fibroblasts as shown in this paper. These different responses of transformed cells to nutritional stress should be taken into account when designing anti-cancer therapies that aim to exploit metabolic differences between normal and transformed cells.

Dataset Information

K-Ras Activation Induces Differential Sensitivity to Sulfur Amino Acid Limitation and Deprivation and to Oxidative and Anti-Oxidative Stress in Mouse Fibroblasts.

Background

Methodology and principal findings

Conclusions and significance

Publications

K-Ras Activation Induces Differential Sensitivity to Sulfur Amino Acid Limitation and Deprivation and to Oxidative and Anti-Oxidative Stress in Mouse Fibroblasts.

Similar Datasets

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