Glutathione S-transferases as molecular markers of tumour progression and prognosis in renal cell carcinoma

Aims: Renal cell carcinoma (RCC) often recurs as distant metastasis; there is thus a need for new indicators to identify high-risk patients. Glutathione S-transferases (GST)- and -π are involved in the renal bioactivation of toxic metabolites. The aim was to investigate whether their expression is of diagnostic and prognostic value. Methods and results: Western blotting of microdissected normal kidney and immunostaining of histological RCC microarrays shows expression of GST- in proximal tubular cells, while GST-π was found in the distal nephron. Of the primary 174 RCC cases examined, GST- immunoreactivity was restricted to conventional RCC (n = 76, 68% positive) and was not seen in any other RCC subtypes. The cross-tabulation of the GST- scores with other prognostic indices demonstrated that GST- immunostaining was significantly more frequent in low-grade tumours (χ2: P < 0.004), and that conventional GST--positive RCC patients had a mean disease-free survival of 6.0 years (95% confidence interval 5.33–6.63), compared with 4.7 years (3.54–5.90) in GST--negative tumours (Kaplan–Meier survival analysis, P = 0.011, log-rank test). Conclusions: GST- is a highly specific diagnostic marker for primary conventional RCC, where it is a prognostic marker if grade is omitted from the multivariate analysis

Microarray analysis of gene expression of mouse hepatocytes of different ploidy

Polyploidisation in hepatocytes has been associated with many physiologic and pathologic processes such as proliferation, metabolism, regeneration, aging, and cancer. We studied gene expression patterns in hepatocytes of different ploidy. Primary hepatocytes were obtained from mice of different ages: young (4-6 weeks old), adult (8-10 weeks old), and older (22-24 weeks old). Diploid (2N), tetraploid (4N), and octoploid (8N) hepatocytes were isolated for studies using a high-density mouse genome microarray. No major changes of gene expression patterns between hepatocytes of different ploidy were found. Fifty genes were identified as differentially expressed in the diploid and tetraploid populations, but the changes were less than twofold either way. Four genes (Gas2, Igfbp2, Nr1i3, and Ccne2) were differentially expressed in tetraploid and octoploid cells. This was confirmed in two age groups, "adult" and "older," but once again the factors were less than twofold and the expressions of Gas2 and Igfbp2 were more different between age groups than between ploidy classes. Our results show that polyploid hepatocytes are stable and "normal" without aberrant gene expression, unlike what is thought for cancer cells. By contrast to megakaryocytes, hepatocyte polyploidisation is not a differentiation step associated with major changes in gene expression. Our data support the hypothesis that hepatocyte polyploidisation is a protective mechanism against oxidative stress that occurs via a controlled process throughout growth and aging where binucleation is important

Microarray analysis of gene expression of mouse hepatocytes of different ploidy

Polyploidisation in hepatocytes has been associated with many physiologic and pathologic processes such as proliferation, metabolism, regeneration, aging, and cancer. We studied gene expression patterns in hepatocytes of different ploidy. Primary hepatocytes were obtained from mice of different ages: young (4-6 weeks old), adult (8-10 weeks old), and older (22-24 weeks old). Diploid (2N), tetraploid (4N), and octoploid (8N) hepatocytes were isolated for studies using a high-density mouse genome microarray. No major changes of gene expression patterns between hepatocytes of different ploidy were found. Fifty genes were identified as differentially expressed in the diploid and tetraploid populations, but the changes were less than twofold either way. Four genes (Gas2, Igfbp2, Nr1i3, and Ccne2) were differentially expressed in tetraploid and octoploid cells. This was confirmed in two age groups, "adult" and "older," but once again the factors were less than twofold and the expressions of Gas2 and Igfbp2 were more different between age groups than between ploidy classes. Our results show that polyploid hepatocytes are stable and "normal" without aberrant gene expression, unlike what is thought for cancer cells. By contrast to megakaryocytes, hepatocyte polyploidisation is not a differentiation step associated with major changes in gene expression. Our data support the hypothesis that hepatocyte polyploidisation is a protective mechanism against oxidative stress that occurs via a controlled process throughout growth and aging where binucleation is important

Expression and localization of rat aldoketo reductases and induction of the 1B13 and 1D2 isoforms by phenolic antioxidants. Drug Metab. Dispos

ABSTRACT: The aldo-keto reductase (AKR) phase I drug metabolism enzyme superfamily is implicated in detoxification or bioactivation of a wide variety of carbonyl-bearing compounds. In this study, we have used antibodies raised against purified recombinant rat AKR isoforms 1A3, 1B4, 1C9, 1D2, and 7A1 to characterize the expression profile of these superfamily members in the rat and define their localization by immunohistochemistry. Western blotting showed that AKR1A3, AKR1B4, and AKR1C9 are ubiquitously expressed, whereas AKR1D2 and AKR7A1 are present in liver, adrenal gland, and kidney, with the latter also present in testis, spleen, and stomach. Immunohistochemical analysis of the kidney demonstrated the localization of AKR1A3 in proximal convoluted tubules, AKR1B4 in the loop of Henle, and AKR1C9 in the pars recta S3 segment of proximal tubules. We also report localization of AKR1B4 in the adrenal gland (parenchymal cells of the zona reticularis) and testis (Sertoli cells and late spermatids), of AKR1D2 in the liver (hepatocyte nuclei), and of AKR7A1 in the pancreatic duct and bronchiolar epithelium. Previous studies have shown that expression of AKR7A1 is induced in response to dietary administration of the phenolic antioxidants butylated hydroxyanisole and ethoxyquin. Here we identify AKR1B13 and AKR1D2 as further inducible members of the rat AKR superfamily