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Elevation of sulfatides in ovarian cancer: an integrated transcriptomic and lipidomic analysis including tissue-imaging mass spectrometry.

Liu Y, Chen Y, Momin A, Shaner R, Wang E, Bowen NJ, Matyunina LV, Walker LD, McDonald JF, Sullards MC, Merrill AH - Mol. Cancer (2010)

Bottom Line: The regions where ST were detected by MALDI-TIMS overlapped with the ovarian epithelial carcinoma as identified by H & E staining and histological scoring.Furthermore, the structures for the most prevalent species observed via MALDI-TIMS (d18:1/C16:0-, d18:1/C24:1- and d18:1/C24:0-ST) were confirmed by MALDI-TIMS/MS, whereas, a neighboring ion(m/z 885.6) that was not tumor specific was identified as a phosphatidylinositol.Microarray analysis of mRNAs collected using laser capture microdissection revealed that expression of GalCer synthase and Gal3ST1 (3'-phosphoadenosine-5'-phosphosulfate:GalCer sulfotransferase) were approximately 11- and 3.5-fold higher, respectively, in the ovarian epithelial carcinoma cells versus normal ovarian stromal tissue, and they were 5- and 2.3-fold higher in comparison with normal surface ovarian epithelial cells, which is a likely explanation for the higher ST.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Biology and the Petit Institute for Bioscience and Bioengineering, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, Georgia 30332-0363, USA.

ABSTRACT

Background: Sulfatides (ST) are a category of sulfated galactosylceramides (GalCer) that are elevated in many types of cancer including, possibly, ovarian cancer. Previous evidence for elevation of ST in ovarian cancer was based on a colorimetric reagent that does not provide structural details and can also react with other lipids. Therefore, this study utilized mass spectrometry for a structure-specific and quantitative analysis of the types, amounts, and tissue localization of ST in ovarian cancer, and combined these findings with analysis of mRNAs for the relevant enzymes of ST metabolism to explore possible mechanisms.

Results: Analysis of 12 ovarian tissues graded as histologically normal or having epithelial ovarian tumors by liquid chromatography electrospray ionization-tandem mass spectrometry (LC ESI-MS/MS) established that most tumor-bearing tissues have higher amounts of ST. Because ovarian cancer tissues are comprised of many different cell types, histological tissue slices were analyzed by matrix-assisted laser desorption ionization-tissue-imaging MS (MALDI-TIMS). The regions where ST were detected by MALDI-TIMS overlapped with the ovarian epithelial carcinoma as identified by H & E staining and histological scoring. Furthermore, the structures for the most prevalent species observed via MALDI-TIMS (d18:1/C16:0-, d18:1/C24:1- and d18:1/C24:0-ST) were confirmed by MALDI-TIMS/MS, whereas, a neighboring ion(m/z 885.6) that was not tumor specific was identified as a phosphatidylinositol. Microarray analysis of mRNAs collected using laser capture microdissection revealed that expression of GalCer synthase and Gal3ST1 (3'-phosphoadenosine-5'-phosphosulfate:GalCer sulfotransferase) were approximately 11- and 3.5-fold higher, respectively, in the ovarian epithelial carcinoma cells versus normal ovarian stromal tissue, and they were 5- and 2.3-fold higher in comparison with normal surface ovarian epithelial cells, which is a likely explanation for the higher ST.

Conclusions: This study combined transcriptomic and lipidomic approaches to establish that sulfatides are elevated in ovarian cancer and should be evaluated further as factors that might be important in ovarian cancer biology and, possibly, as biomarkers.

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Related in: MedlinePlus

Differences in the level of expression of genes for sphingolipid biosynthesis through sulfatides, ST, and the amounts of ST in epithelial ovarian tumors versus normal ovarian stromal tissues. (A) The relative levels of mRNA for the enzymes of the shown steps of the de novo sphingolipid biosynthesis pathway were imported into a KEGG style pathway heatmap [15] with fold differences in gene expression for ovarian cancer/normal stromal cells are represented by the color scale (red = higher; blue = lower). In this depiction, the pathway begins in the upper left corner with the condensation of serine and palmitoyl-CoA by serine palmitoyltransferase (SPT, shown for its three known genes) to form 3-ketosphinganine (3KSa) which is converted to sphinganine (Sa) by 3KSa reductase. Sa is N-acylated to dihydroceramide (DHCer) by a family of Cer synthases (CerS), desaturated (by DHCer desaturases, DES), and converted to sphingomyelin (SM) by SM synthases (SMS), phosphorylated to Cer 1-phosphate by Cer kinase (CERK) (this branch of sphingolipid biosynthesis is also thought to involve a Cer transport protein, CERT), or glycosylated to glucosylceramide (GlcCer) or galactosylceramide (GalCer), which can undergo sulfation to ST by GalCer sulfotransferase (Gal3ST1). Also shown are the steps of ST turnover, via aryl sulfatase (ARSA) and galactocerebrosidase (GALC) which operate in concert with prosaposins (PSAP), and GlcCer turnover via glucosylcerebrosidase (GBA1). The heat maps depict the normalized level of expression of these genes in the epithelial ovarian tumors divided by the level of expression on normal stromal tissues averaged for the 12 patients and 8 controls. (B and C) Amounts of the various N-acyl-chain length subspecies of ST as measured by LC ESI-MS/MS for clinically similar patients with ovarian carcinoma (B, n = 12) or normal ovary (C, n = 12).
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Figure 1: Differences in the level of expression of genes for sphingolipid biosynthesis through sulfatides, ST, and the amounts of ST in epithelial ovarian tumors versus normal ovarian stromal tissues. (A) The relative levels of mRNA for the enzymes of the shown steps of the de novo sphingolipid biosynthesis pathway were imported into a KEGG style pathway heatmap [15] with fold differences in gene expression for ovarian cancer/normal stromal cells are represented by the color scale (red = higher; blue = lower). In this depiction, the pathway begins in the upper left corner with the condensation of serine and palmitoyl-CoA by serine palmitoyltransferase (SPT, shown for its three known genes) to form 3-ketosphinganine (3KSa) which is converted to sphinganine (Sa) by 3KSa reductase. Sa is N-acylated to dihydroceramide (DHCer) by a family of Cer synthases (CerS), desaturated (by DHCer desaturases, DES), and converted to sphingomyelin (SM) by SM synthases (SMS), phosphorylated to Cer 1-phosphate by Cer kinase (CERK) (this branch of sphingolipid biosynthesis is also thought to involve a Cer transport protein, CERT), or glycosylated to glucosylceramide (GlcCer) or galactosylceramide (GalCer), which can undergo sulfation to ST by GalCer sulfotransferase (Gal3ST1). Also shown are the steps of ST turnover, via aryl sulfatase (ARSA) and galactocerebrosidase (GALC) which operate in concert with prosaposins (PSAP), and GlcCer turnover via glucosylcerebrosidase (GBA1). The heat maps depict the normalized level of expression of these genes in the epithelial ovarian tumors divided by the level of expression on normal stromal tissues averaged for the 12 patients and 8 controls. (B and C) Amounts of the various N-acyl-chain length subspecies of ST as measured by LC ESI-MS/MS for clinically similar patients with ovarian carcinoma (B, n = 12) or normal ovary (C, n = 12).

Mentions: Using data from a recent study of gene expression in ovarian cancer [11], the fold differences in the mRNAs for enzymes of the early steps of sphingolipid biosynthesis and turnover were calculated and displayed in a heat map format in Figure 1A with the metabolic steps depicted as a KEGG pathway-style diagram [14] that has been recently updated [15]. It is evident from this depiction that the mRNAs for several of the enzymes of ST biosynthesis--most notably GalCer synthase (also called ceramide galactosyltransferase, UGT8) and GalCer sulfotransferase (Gal3ST1)--are higher for the ovarian carcinoma cells versus normal stromal tissue, whereas those for ST turnover are not different (arylsulfatase, ARSA, galactosylceramidase, GALC, and possibly the related saposins, based on the pro-saposin mRNA PSAP). In addition, mRNAs for two of the three enzymes that also utilize Cer for biosynthesis of other sphingolipids (sphingomyelin synthase 1, SMS1, and ceramide kinase, CERK) and the Cer transport protein CERT appear to be lower for the carcinoma cells versus normal stromal tissue. Therefore, these findings would predict that ovarian carcinoma cells could have higher ST versus normal stromal tissue, as had been suggested by an earlier analysis of ST in this cancer [9].


Elevation of sulfatides in ovarian cancer: an integrated transcriptomic and lipidomic analysis including tissue-imaging mass spectrometry.

Liu Y, Chen Y, Momin A, Shaner R, Wang E, Bowen NJ, Matyunina LV, Walker LD, McDonald JF, Sullards MC, Merrill AH - Mol. Cancer (2010)

Differences in the level of expression of genes for sphingolipid biosynthesis through sulfatides, ST, and the amounts of ST in epithelial ovarian tumors versus normal ovarian stromal tissues. (A) The relative levels of mRNA for the enzymes of the shown steps of the de novo sphingolipid biosynthesis pathway were imported into a KEGG style pathway heatmap [15] with fold differences in gene expression for ovarian cancer/normal stromal cells are represented by the color scale (red = higher; blue = lower). In this depiction, the pathway begins in the upper left corner with the condensation of serine and palmitoyl-CoA by serine palmitoyltransferase (SPT, shown for its three known genes) to form 3-ketosphinganine (3KSa) which is converted to sphinganine (Sa) by 3KSa reductase. Sa is N-acylated to dihydroceramide (DHCer) by a family of Cer synthases (CerS), desaturated (by DHCer desaturases, DES), and converted to sphingomyelin (SM) by SM synthases (SMS), phosphorylated to Cer 1-phosphate by Cer kinase (CERK) (this branch of sphingolipid biosynthesis is also thought to involve a Cer transport protein, CERT), or glycosylated to glucosylceramide (GlcCer) or galactosylceramide (GalCer), which can undergo sulfation to ST by GalCer sulfotransferase (Gal3ST1). Also shown are the steps of ST turnover, via aryl sulfatase (ARSA) and galactocerebrosidase (GALC) which operate in concert with prosaposins (PSAP), and GlcCer turnover via glucosylcerebrosidase (GBA1). The heat maps depict the normalized level of expression of these genes in the epithelial ovarian tumors divided by the level of expression on normal stromal tissues averaged for the 12 patients and 8 controls. (B and C) Amounts of the various N-acyl-chain length subspecies of ST as measured by LC ESI-MS/MS for clinically similar patients with ovarian carcinoma (B, n = 12) or normal ovary (C, n = 12).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2913985&req=5

Figure 1: Differences in the level of expression of genes for sphingolipid biosynthesis through sulfatides, ST, and the amounts of ST in epithelial ovarian tumors versus normal ovarian stromal tissues. (A) The relative levels of mRNA for the enzymes of the shown steps of the de novo sphingolipid biosynthesis pathway were imported into a KEGG style pathway heatmap [15] with fold differences in gene expression for ovarian cancer/normal stromal cells are represented by the color scale (red = higher; blue = lower). In this depiction, the pathway begins in the upper left corner with the condensation of serine and palmitoyl-CoA by serine palmitoyltransferase (SPT, shown for its three known genes) to form 3-ketosphinganine (3KSa) which is converted to sphinganine (Sa) by 3KSa reductase. Sa is N-acylated to dihydroceramide (DHCer) by a family of Cer synthases (CerS), desaturated (by DHCer desaturases, DES), and converted to sphingomyelin (SM) by SM synthases (SMS), phosphorylated to Cer 1-phosphate by Cer kinase (CERK) (this branch of sphingolipid biosynthesis is also thought to involve a Cer transport protein, CERT), or glycosylated to glucosylceramide (GlcCer) or galactosylceramide (GalCer), which can undergo sulfation to ST by GalCer sulfotransferase (Gal3ST1). Also shown are the steps of ST turnover, via aryl sulfatase (ARSA) and galactocerebrosidase (GALC) which operate in concert with prosaposins (PSAP), and GlcCer turnover via glucosylcerebrosidase (GBA1). The heat maps depict the normalized level of expression of these genes in the epithelial ovarian tumors divided by the level of expression on normal stromal tissues averaged for the 12 patients and 8 controls. (B and C) Amounts of the various N-acyl-chain length subspecies of ST as measured by LC ESI-MS/MS for clinically similar patients with ovarian carcinoma (B, n = 12) or normal ovary (C, n = 12).
Mentions: Using data from a recent study of gene expression in ovarian cancer [11], the fold differences in the mRNAs for enzymes of the early steps of sphingolipid biosynthesis and turnover were calculated and displayed in a heat map format in Figure 1A with the metabolic steps depicted as a KEGG pathway-style diagram [14] that has been recently updated [15]. It is evident from this depiction that the mRNAs for several of the enzymes of ST biosynthesis--most notably GalCer synthase (also called ceramide galactosyltransferase, UGT8) and GalCer sulfotransferase (Gal3ST1)--are higher for the ovarian carcinoma cells versus normal stromal tissue, whereas those for ST turnover are not different (arylsulfatase, ARSA, galactosylceramidase, GALC, and possibly the related saposins, based on the pro-saposin mRNA PSAP). In addition, mRNAs for two of the three enzymes that also utilize Cer for biosynthesis of other sphingolipids (sphingomyelin synthase 1, SMS1, and ceramide kinase, CERK) and the Cer transport protein CERT appear to be lower for the carcinoma cells versus normal stromal tissue. Therefore, these findings would predict that ovarian carcinoma cells could have higher ST versus normal stromal tissue, as had been suggested by an earlier analysis of ST in this cancer [9].

Bottom Line: The regions where ST were detected by MALDI-TIMS overlapped with the ovarian epithelial carcinoma as identified by H & E staining and histological scoring.Furthermore, the structures for the most prevalent species observed via MALDI-TIMS (d18:1/C16:0-, d18:1/C24:1- and d18:1/C24:0-ST) were confirmed by MALDI-TIMS/MS, whereas, a neighboring ion(m/z 885.6) that was not tumor specific was identified as a phosphatidylinositol.Microarray analysis of mRNAs collected using laser capture microdissection revealed that expression of GalCer synthase and Gal3ST1 (3'-phosphoadenosine-5'-phosphosulfate:GalCer sulfotransferase) were approximately 11- and 3.5-fold higher, respectively, in the ovarian epithelial carcinoma cells versus normal ovarian stromal tissue, and they were 5- and 2.3-fold higher in comparison with normal surface ovarian epithelial cells, which is a likely explanation for the higher ST.

View Article: PubMed Central - HTML - PubMed

Affiliation: School of Biology and the Petit Institute for Bioscience and Bioengineering, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, Georgia 30332-0363, USA.

ABSTRACT

Background: Sulfatides (ST) are a category of sulfated galactosylceramides (GalCer) that are elevated in many types of cancer including, possibly, ovarian cancer. Previous evidence for elevation of ST in ovarian cancer was based on a colorimetric reagent that does not provide structural details and can also react with other lipids. Therefore, this study utilized mass spectrometry for a structure-specific and quantitative analysis of the types, amounts, and tissue localization of ST in ovarian cancer, and combined these findings with analysis of mRNAs for the relevant enzymes of ST metabolism to explore possible mechanisms.

Results: Analysis of 12 ovarian tissues graded as histologically normal or having epithelial ovarian tumors by liquid chromatography electrospray ionization-tandem mass spectrometry (LC ESI-MS/MS) established that most tumor-bearing tissues have higher amounts of ST. Because ovarian cancer tissues are comprised of many different cell types, histological tissue slices were analyzed by matrix-assisted laser desorption ionization-tissue-imaging MS (MALDI-TIMS). The regions where ST were detected by MALDI-TIMS overlapped with the ovarian epithelial carcinoma as identified by H & E staining and histological scoring. Furthermore, the structures for the most prevalent species observed via MALDI-TIMS (d18:1/C16:0-, d18:1/C24:1- and d18:1/C24:0-ST) were confirmed by MALDI-TIMS/MS, whereas, a neighboring ion(m/z 885.6) that was not tumor specific was identified as a phosphatidylinositol. Microarray analysis of mRNAs collected using laser capture microdissection revealed that expression of GalCer synthase and Gal3ST1 (3'-phosphoadenosine-5'-phosphosulfate:GalCer sulfotransferase) were approximately 11- and 3.5-fold higher, respectively, in the ovarian epithelial carcinoma cells versus normal ovarian stromal tissue, and they were 5- and 2.3-fold higher in comparison with normal surface ovarian epithelial cells, which is a likely explanation for the higher ST.

Conclusions: This study combined transcriptomic and lipidomic approaches to establish that sulfatides are elevated in ovarian cancer and should be evaluated further as factors that might be important in ovarian cancer biology and, possibly, as biomarkers.

Show MeSH
Related in: MedlinePlus