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Metabolomic profiling reveals a role for androgen in activating amino acid metabolism and methylation in prostate cancer cells.

Putluri N, Shojaie A, Vasu VT, Nalluri S, Vareed SK, Putluri V, Vivekanandan-Giri A, Byun J, Pennathur S, Sana TR, Fischer SM, Palapattu GS, Creighton CJ, Michailidis G, Sreekumar A - PLoS ONE (2011)

Bottom Line: Metastatic tumors are initially responsive to anti-androgen therapy, however become resistant to this regimen upon progression.Our findings indicate that androgen exposure results in elevation of amino acid metabolism and alteration of methylation potential in prostate cancer cells.Further, metabolic phenotyping studies confirm higher flux through pathways associated with amino acid metabolism in prostate cancer cells treated with androgen.

View Article: PubMed Central - PubMed

Affiliation: Cancer Center, Medical College of Georgia, Augusta, Georgia, United States of America.

ABSTRACT
Prostate cancer is the second leading cause of cancer related death in American men. Development and progression of clinically localized prostate cancer is highly dependent on androgen signaling. Metastatic tumors are initially responsive to anti-androgen therapy, however become resistant to this regimen upon progression. Genomic and proteomic studies have implicated a role for androgen in regulating metabolic processes in prostate cancer. However, there have been no metabolomic profiling studies conducted thus far that have examined androgen-regulated biochemical processes in prostate cancer. Here, we have used unbiased metabolomic profiling coupled with enrichment-based bioprocess mapping to obtain insights into the biochemical alterations mediated by androgen in prostate cancer cell lines. Our findings indicate that androgen exposure results in elevation of amino acid metabolism and alteration of methylation potential in prostate cancer cells. Further, metabolic phenotyping studies confirm higher flux through pathways associated with amino acid metabolism in prostate cancer cells treated with androgen. These findings provide insight into the potential biochemical processes regulated by androgen signaling in prostate cancer. Clinically, if validated, these pathways could be exploited to develop therapeutic strategies that supplement current androgen ablative treatments while the observed androgen-regulated metabolic signatures could be employed as biomarkers that presage the development of castrate-resistant prostate cancer.

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Measurement of metabolic flux in prostate cancer cells upon androgen-treatment.Heat map showing extent of utilization 86 carbohydrate and nucleotide substrates by prostate cancer cells after 24 h of androgen-treatment. Essentially, 10 nM R1881 (treated for 24 h) or untreated VCaP cells were examined in replicates for their ability to utilize the various nutrient substrates (denoted as pathway activity on Y-axis) at different time points (plotted on X-axis) post-androgen-treatment. The ability to metabolize the nutrients was assessed by calculating the flux of NADH generated which was measured by reading the optical density (OD) at 590 nm. The heat map was generated after background subtraction, log scaling and quantile normalization of the data. Shades of yellow indicate increased activity while shades of blue indicate reduced activity (refer color scale). B) same as in (A), but for utilization of 29 amino acids. C) represents the box plot showing the median flux through the sugar and nucleotide (pink) as well as amino acid (brown) pathways in prostate cancer cells at different time points post-androgen treatment. For each boxplot, the median value is represented by the central, horizontal line; the upper (75%) and lower (25%) quartiles are represented by the upper and lower borders of the box. The upper and lower vertical lines extending from the box represent 1.5 times the inter-quartile range from the upper and lower quartiles.
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pone-0021417-g005: Measurement of metabolic flux in prostate cancer cells upon androgen-treatment.Heat map showing extent of utilization 86 carbohydrate and nucleotide substrates by prostate cancer cells after 24 h of androgen-treatment. Essentially, 10 nM R1881 (treated for 24 h) or untreated VCaP cells were examined in replicates for their ability to utilize the various nutrient substrates (denoted as pathway activity on Y-axis) at different time points (plotted on X-axis) post-androgen-treatment. The ability to metabolize the nutrients was assessed by calculating the flux of NADH generated which was measured by reading the optical density (OD) at 590 nm. The heat map was generated after background subtraction, log scaling and quantile normalization of the data. Shades of yellow indicate increased activity while shades of blue indicate reduced activity (refer color scale). B) same as in (A), but for utilization of 29 amino acids. C) represents the box plot showing the median flux through the sugar and nucleotide (pink) as well as amino acid (brown) pathways in prostate cancer cells at different time points post-androgen treatment. For each boxplot, the median value is represented by the central, horizontal line; the upper (75%) and lower (25%) quartiles are represented by the upper and lower borders of the box. The upper and lower vertical lines extending from the box represent 1.5 times the inter-quartile range from the upper and lower quartiles.

Mentions: As shown in Figure 5A and plotted in Figure 5C, upon androgen treatment, prostate cancer cells did not show any time-dependent alteration in metabolism of sugar and nucleotide substrates compared to untreated controls. However, starting at 24 h after androgen addition, these cells exhibit higher metabolism of amino acids compared to untreated cells (Figures 5 B, C). This elevated trend in amino acid metabolism in androgen-treated cells was significant at 27 hrs post hormone treatment and persisted till the 30 h time point (GSA p-values 0.0001 for all three time points, See Statistical Methods for details) (Figures 5 B, C). This increased activity in amino acid pathway correlates well with our cell line-derived metabolic profiles that show androgen driven elevation in levels of these metabolites in prostate cancer. Further, this androgen-mediated increase in amino acid metabolism in prostate cancer cells could potentially result in efficient utilization of methionine (Figure 5B, methionine) that could in turn generate higher levels of SAM, thus altering the methylation potential of the cell.


Metabolomic profiling reveals a role for androgen in activating amino acid metabolism and methylation in prostate cancer cells.

Putluri N, Shojaie A, Vasu VT, Nalluri S, Vareed SK, Putluri V, Vivekanandan-Giri A, Byun J, Pennathur S, Sana TR, Fischer SM, Palapattu GS, Creighton CJ, Michailidis G, Sreekumar A - PLoS ONE (2011)

Measurement of metabolic flux in prostate cancer cells upon androgen-treatment.Heat map showing extent of utilization 86 carbohydrate and nucleotide substrates by prostate cancer cells after 24 h of androgen-treatment. Essentially, 10 nM R1881 (treated for 24 h) or untreated VCaP cells were examined in replicates for their ability to utilize the various nutrient substrates (denoted as pathway activity on Y-axis) at different time points (plotted on X-axis) post-androgen-treatment. The ability to metabolize the nutrients was assessed by calculating the flux of NADH generated which was measured by reading the optical density (OD) at 590 nm. The heat map was generated after background subtraction, log scaling and quantile normalization of the data. Shades of yellow indicate increased activity while shades of blue indicate reduced activity (refer color scale). B) same as in (A), but for utilization of 29 amino acids. C) represents the box plot showing the median flux through the sugar and nucleotide (pink) as well as amino acid (brown) pathways in prostate cancer cells at different time points post-androgen treatment. For each boxplot, the median value is represented by the central, horizontal line; the upper (75%) and lower (25%) quartiles are represented by the upper and lower borders of the box. The upper and lower vertical lines extending from the box represent 1.5 times the inter-quartile range from the upper and lower quartiles.
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Related In: Results  -  Collection

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pone-0021417-g005: Measurement of metabolic flux in prostate cancer cells upon androgen-treatment.Heat map showing extent of utilization 86 carbohydrate and nucleotide substrates by prostate cancer cells after 24 h of androgen-treatment. Essentially, 10 nM R1881 (treated for 24 h) or untreated VCaP cells were examined in replicates for their ability to utilize the various nutrient substrates (denoted as pathway activity on Y-axis) at different time points (plotted on X-axis) post-androgen-treatment. The ability to metabolize the nutrients was assessed by calculating the flux of NADH generated which was measured by reading the optical density (OD) at 590 nm. The heat map was generated after background subtraction, log scaling and quantile normalization of the data. Shades of yellow indicate increased activity while shades of blue indicate reduced activity (refer color scale). B) same as in (A), but for utilization of 29 amino acids. C) represents the box plot showing the median flux through the sugar and nucleotide (pink) as well as amino acid (brown) pathways in prostate cancer cells at different time points post-androgen treatment. For each boxplot, the median value is represented by the central, horizontal line; the upper (75%) and lower (25%) quartiles are represented by the upper and lower borders of the box. The upper and lower vertical lines extending from the box represent 1.5 times the inter-quartile range from the upper and lower quartiles.
Mentions: As shown in Figure 5A and plotted in Figure 5C, upon androgen treatment, prostate cancer cells did not show any time-dependent alteration in metabolism of sugar and nucleotide substrates compared to untreated controls. However, starting at 24 h after androgen addition, these cells exhibit higher metabolism of amino acids compared to untreated cells (Figures 5 B, C). This elevated trend in amino acid metabolism in androgen-treated cells was significant at 27 hrs post hormone treatment and persisted till the 30 h time point (GSA p-values 0.0001 for all three time points, See Statistical Methods for details) (Figures 5 B, C). This increased activity in amino acid pathway correlates well with our cell line-derived metabolic profiles that show androgen driven elevation in levels of these metabolites in prostate cancer. Further, this androgen-mediated increase in amino acid metabolism in prostate cancer cells could potentially result in efficient utilization of methionine (Figure 5B, methionine) that could in turn generate higher levels of SAM, thus altering the methylation potential of the cell.

Bottom Line: Metastatic tumors are initially responsive to anti-androgen therapy, however become resistant to this regimen upon progression.Our findings indicate that androgen exposure results in elevation of amino acid metabolism and alteration of methylation potential in prostate cancer cells.Further, metabolic phenotyping studies confirm higher flux through pathways associated with amino acid metabolism in prostate cancer cells treated with androgen.

View Article: PubMed Central - PubMed

Affiliation: Cancer Center, Medical College of Georgia, Augusta, Georgia, United States of America.

ABSTRACT
Prostate cancer is the second leading cause of cancer related death in American men. Development and progression of clinically localized prostate cancer is highly dependent on androgen signaling. Metastatic tumors are initially responsive to anti-androgen therapy, however become resistant to this regimen upon progression. Genomic and proteomic studies have implicated a role for androgen in regulating metabolic processes in prostate cancer. However, there have been no metabolomic profiling studies conducted thus far that have examined androgen-regulated biochemical processes in prostate cancer. Here, we have used unbiased metabolomic profiling coupled with enrichment-based bioprocess mapping to obtain insights into the biochemical alterations mediated by androgen in prostate cancer cell lines. Our findings indicate that androgen exposure results in elevation of amino acid metabolism and alteration of methylation potential in prostate cancer cells. Further, metabolic phenotyping studies confirm higher flux through pathways associated with amino acid metabolism in prostate cancer cells treated with androgen. These findings provide insight into the potential biochemical processes regulated by androgen signaling in prostate cancer. Clinically, if validated, these pathways could be exploited to develop therapeutic strategies that supplement current androgen ablative treatments while the observed androgen-regulated metabolic signatures could be employed as biomarkers that presage the development of castrate-resistant prostate cancer.

Show MeSH
Related in: MedlinePlus