Structure and promoter characterization of aldo-keto reductase family 1B10 gene

Department of Medical Microbiology, Immunology, and Cell Biology, SimmonsCooper Cancer Institute, Southern Illinois University School of Medicine, 913 N. Rutledge Street, Springfield, IL 62702, USA.
Gene (Impact Factor: 2.14). 03/2009; 437(1-2):39-44. DOI: 10.1016/j.gene.2009.02.007
Source: PubMed


Aldo-keto reductase family 1 member B10 (AKR1B10) is overexpressed in human hepatocellular carcinoma, lung squamous carcinoma, and lung adenocarcinoma in smokers. Our recent studies have showed that AKR1B10 plays a critical role in the growth and proliferation of cancer cells by detoxifying reactive carbonyls and regulating fatty acid biosynthesis. However, little is known about the regulatory mechanisms of AKR1B10 expression. In this study, we determined the structure of AKR1B10 gene and characterized its promoter. The results demonstrated that AKR1B10 consists of 10 exons and 9 introns, stretching approximately 13.8 kb. A 5'-RACE study determined the transcriptional start site of AKR1B10 at 320 bp upstream of the ATG translational start codon. A TATA-like (TAATAA) and a CAAT box are present from -145 to -140 bp and -193 to -190 bp upstream of the transcriptional start site, respectively. Motif analysis recognized multiple putative oncogenic and tumor suppressor protein binding sites in the AKR1B10 promoter, including c-Ets-1, C/EBP, AP-1, and p53, but osmolytic response elements were not found. A -4091 bp of the 5'-flanking fragment of the AKR1B10 gene was capable of driving GFP and luciferase reporter gene expression in HepG2 cells derived from human hepatocellular carcinoma; progressive 5'-deletions revealed that a -255 bp fragment possesses full promoter activity.

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Available from: Linlin Zhong, Aug 27, 2014
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    • "The cancer-associated overexpression of AKR1B10 probably results from an adaptive response to oncogenic processes, but little is known about its gene regulation. Liu et al. (2009b) characterized the promoter region of the AKR1B10 gene, which includes multiple putative oncogenic and tumor suppressor protein binding sites, including the transcriptional factors c-Ets-1 and C/EBP, the repressor protein p53, and the AP-1 oncogene. Nishinaka et al. (2011) identified several putative regulatory motifs, such as AP- 1, NF-κB, and antioxidant response element, in a −3282 bp of the 5 -flanking region and 5 -untranslation region of AKR1B10 gene, and also suggest a possibility that a complex polymorphic microsatellite in this region is implicated in the enzyme induction in response to certain stimuli such as carcinogens. "
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    ABSTRACT: The human aldo-keto reductase AKR1B10, originally identified as an aldose reductase-like protein and human small intestine aldose reductase, is a cytosolic NADPH-dependent reductase that metabolizes a variety of endogenous compounds, such as aromatic and aliphatic aldehydes and dicarbonyl compounds, and some drug ketones. The enzyme is highly expressed in solid tumors of several tissues including lung and liver, and as such has received considerable interest as a relevant biomarker for the development of those tumors. In addition, AKR1B10 has been recently reported to be significantly up-regulated in some cancer cell lines (medulloblastoma D341 and colon cancer HT29) acquiring resistance toward chemotherapeutic agents (cyclophosphamide and mitomycin c), suggesting the validity of the enzyme as a chemoresistance marker. Although the detailed information on the AKR1B10-mediated mechanisms leading to the drug resistance process is not well understood so far, the enzyme has been proposed to be involved in functional regulations of cell proliferation and metabolism of drugs and endogenous lipids during the development of chemoresistance. This article reviews the current literature focusing mainly on expression profile and roles of AKR1B10 in the drug resistance of cancer cells. Recent developments of AKR1B10 inhibitors and their usefulness in restoring sensitivity to anticancer drugs are also reviewed.
    Full-text · Article · Jan 2012 · Frontiers in Pharmacology
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    • "Over-expression of AKR1B10 has been identified in hepatocellular carcinoma and non-small cell lung carcinomas. Further studies suggest that AKR1B10 is a unique biomarker of smoking related cancer and that AKR1B10 can be activated by tobacco-related carcinogenic transcription factors [3, 4],[5]. Since smoking is the most clearly established risk factor for pancreatic cancer and is associated with KRAS mutations[6], it is reasonable to postulate the AKR1B10 is up-regulated in human pancreatic cancer. "
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    ABSTRACT: Aldo-keto reductase family 1B10 (AKR1B10) exhibits more restricted lipid substrate specificity (including farnesal, geranylgeranial, retinal and carbonyls), and metabolizing these lipid substrates has a crucial role in promoting carcinogenesis. Overexpression of AKR1B10 has been identified in smoking-related carcinomas such as lung cancer. As development of pancreatic cancer is firmly linked to smoking, the aim of the present study was to examine the expression and oncogenic role of AKR1B10 in pancreatic adenocarcinoma. AKR1B10 expression was analyzed in 50 paraffin-embedded clinical pancreatic cancer samples using immunohistochemistry. Oncogenic function of AKR1B10 was examined in pancreatic carcinoma cells in vitro using western blotting and siRNA approaches, mainly on cell apoptosis and protein prenylation including KRAS protein and its downstream signals. Immunohistochemistry analysis revealed that AKR1B10 overexpressed in 70% (35/50) of pancreatic adenocarcinomas and majority of pancreatic intraepithelial neoplasia, but not in adjacent morphologically normal pancreatic tissue. Compared with a normal pancreatic ductal epithelial cell (HPDE6E7), all of the six cultured pancreatic adenocarcinoma cell lines had an overexpression of AKR1B10 using immunoblotting, which correlated with increase of enzyme activity. siRNA-mediated silencing of AKR1B10 expression in pancreatic cancer cells resulted in (1) increased cell apoptosis, (2) increased non-farnesyled HDJ2 protein and (3) decreased membrane-bound prenylated KRAS protein and its downstream signaling molecules including phosphorylated ERK and MEK and membrane-bound E-cadherin. Our findings provide first time evidence that AKR1B10 is a unique enzyme involved in pancreatic carcinogenesis possibly via modulation of cell apoptosis and protein prenylation.
    Full-text · Article · Jan 2012 · Modern Pathology
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    • "In these cells, glutathione S-transferases and multidrug resistance-associated proteins were all excluded as factors for daunorubicin resistance and therefore, the daunorubicin resistance is virtually ascribed to the induction of these reductases and their enzymatic detoxification (Ohara et al., 1995; Plebuch et al., 2007; Gavelova et al., 2008). Interestingly, reductases AR, ALR1, and DD are aldo-keto reductase family 1 (AKR1) proteins, where aldo-keto reductase family 1 member B10 (AKR1B10) belongs (Chung and LaMendola, 1989; Jez et al., 1997; Hyndman et al., 2003; Liu et al., 2009). AKR1B10 is a novel NADPH-dependent AKR protein primarily expressed in the human intestine and adrenal gland (Cao et al., 1998; Hyndman and Flynn, 1998). "
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    ABSTRACT: Daunorubicin, idarubicin, doxorubicin and epirubicin are anthracyclines widely used for the treatment of lymphoma, leukemia, and breast, lung, and liver cancers, but tumor resistance limits their clinical success. Aldo-keto reductase family 1 B10 (AKR1B10) is an NADPH-dependent enzyme overexpressed in liver and lung carcinomas. This study was aimed to determine the role of AKR1B10 in tumor resistance to anthracyclines. AKR1B10 activity toward anthracyclines was measured using recombinant protein. Cell resistance to anthracycline was determined by ectopic expression of AKR1B10 or inhibition by epalrestat. Results showed that AKR1B10 reduces C13-ketonic group on side chain of daunorubicin and idarubicin to hydroxyl forms. In vitro, AKR1B10 converted daunorubicin to daunorubicinol at V(max) of 837.42±81.39nmol/mg/min, K(m) of 9.317±2.25mM and k(cat)/K(m) of 3.24. AKR1B10 showed better catalytic efficiency toward idarubicin with V(max) at 460.23±28.12nmol/mg/min, K(m) at 0.461±0.09mM and k(cat)/K(m) at 35.94. AKR1B10 was less active toward doxorubicin and epirubicin with a C14-hydroxyl group. In living cells, AKR1B10 efficiently catalyzed reduction of daunorubicin (50nM) and idarubicin (30nM) to corresponding alcohols. Within 24h, approximately 20±2.7% of daunorubicin (1μM) or 23±2.3% of idarubicin (1μM) was converted to daunorubicinol or idarubicinol in AKR1B10 expression cells compared to 7±0.9% and 5±1.5% in vector control. AKR1B10 expression led to cell resistance to daunorubicin and idarubicin, but inhibitor epalrestat showed a synergistic role with these agents. Together our data suggest that AKR1B10 participates in cellular metabolism of daunorubicin and idarubicin, resulting in drug resistance. These data are informative for the clinical use of idarubicin and daunorubicin.
    Full-text · Article · May 2011 · Toxicology and Applied Pharmacology
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