Organic Anion Transporter Family Research Articles

CDNA Microarray Analysis and Influx Transporter OATP1B1 in Liver Cells After Exposure to Gadoxetate Disodium, a Gadolinium-based Contrast Agent in MRI Liver Imaging.

Gadoxetate disodium (Primovist or Eovist) is extensively used as a hepatospecific contrast agent during magnetic resonance imaging (MRI) examinations. However, there is no information determining whether gadoxetate disodium has a cytotoxic impact and/or affects relative gene expression on liver cells. In the current study, we investigated the effects of gadoxetate disodium on cytotoxicity and the levels of gene expression in human normal Chang Liver cells. The cytotoxic effect was detected via methyl thiazolyl tetrazolium (MTT) assay and 4',6-diamidino-2-phenylindole (DAPI) staining. mRNA expression was monitored by cDNA microarray and quantitative PCR (qPCR) analysis. The protein levels were determined by western blotting. Gadoxetate disodium at 5 and 10 mM failed to induce any cell cytotoxicity and morphological changes in Chang Liver cells. Our data demonstrated that gadoxetate disodium significantly enhanced the expression of 29 genes and suppressed that of 27. The SLCO1C1 (solute carrier organic anion transporter family member 1C1) mRNA expression was also increased by 2.62-fold (p-value=0.0006) in gadoxetate disodium-treated cells. Furthermore, we also checked and found that gadoxetate disodium up-regulated organic anion transporter polypeptide 1B1 (OATP1B1) protein level and increased OATP uptake transporter gene SLCO1C1 mRNA expression. Our results provide evidence regarding that gadoxetate disodium might be no cytotoxic effects on liver cells.

SLCO1B1 Polymorphism Is a Drug Response Predictive Marker for Advanced Pancreatic Cancer Patients Treated With Gemcitabine, S-1, or Gemcitabine Plus S-1.

The aim of this study was to evaluate the effects of single-nucleotide polymorphisms (SNPs) on advanced pancreatic cancer risk and overall survival (OS) in a candidate-gene approach. Overall, 5438 SNPs in 219 candidate genes encoding several drug-metabolizing enzymes or transporters were analyzed. In the screening study, 3 SNPs were found associated with OS (P ≤ 0.0005). We validated these SNPs as part of the randomized phase 3 study (GEST study). The associations between OS and SNPs were investigated using log-rank test and Cox proportional hazards model. From the GEST study, the SNP rs4149086 in the 3' UTR of the solute carrier organic anion transporter family member 1B1 (SLCO1B1) gene showed significant interaction with treatment (P = 0.02). In the gemcitabine group, the SNP was associated with short OS (hazard ratio [HR], 3.75; 95% confidence interval [CI], 1.30-10.8; P = 0.008) even after multiple-comparisons adjustment. In contrast, the SNP was not associated with OS in S-1 (HR, 0.77; 95% CI, 0.33-1.81; P = 0.55) or gemcitabine plus S-1 groups (HR, 1.18; 95% CI, 0.46-3.00; P = 0.72). Patients with advanced pancreatic cancer with the rs4149086 AG or GG genotype may obtain good clinical results when treated with S-1-containing regimens.

136P - Drug transporter pharmacogenetics as a predictor of chemotherapy-induced toxicity in lung cancer patients

Background: Lung cancer remains the commonest cancer and the most common cause of cancer-associated death worldwide. Use of chemotherapeutic drugs are significant in managing patients with lung cancer, however, due to serious adverse drug reactions (ADRs) these drugs are often underutilized. Our aim was to perform a meta-analysis and systematic review of studies looking at pharmacogenetic drug transporter variants as predictors of ADRs in lung cancer patients undergoing chemotherapy. Methods: Papers were sourced from Medline, Cochrane Library, CINHL, EMBASE, Web of Knowledge and Scopus. The Cochrane Collaboration Risk of Bias Tool v13 was used to evaluate six types of bias domains for each of the publications reviewed. Where applicable, random effect meta-analysis was used and funnel plots displayed. Results: We report findings on the ATP-binding cassette superfamily (ABC) members ABCB1, ABCC1, ABCC2, ABCG2, ABCA1, ABCC4 and ABCC5. For influx transporters, findings for the solute carrier organic anion transporter family (SLC, SLCO) SLC29A1, SLC2A3, SLC31A1, SLCO1B1 and SLCO1B3 are included. Significant increased risk of irinotecan-induced neutropenia was noted in NSCLC patients expressing ABCB1 2677G>T/G (P = 0.002) or ABCC2 3972T>T (P = 0.04). ABCG2 421C>A was associated with a significant 2-fold increased risk of gefitinib-induced skin toxicity (P = 0.0009). East-Asian patients treated with irinotecan and expressing the SLCO1B1 -1118G>A variant had a 2 -3 fold significant increased risk of diarrhea and neutropenia (P < 0.05). American patients expressing the SLC19A1 IVS2(4935)G>A variant were associated with pemetrexed/gemcitabine induced grade 3+ leukopenia. Conclusions: Whilst current data shows promise regarding ABCB1, ABCC2, ABCG2, SLCO1B1 and SLC19A1 pharmacogenetics, many more studies are required that incorporate larger patient numbers and designed to minimize bias before we can begin to utilizes these variants to optimize chemotherapeutic treatment. Legal entity responsible for the study: Zoulikha Zair Funding: Has not received any funding Disclosure: All authors have declared no conflicts of interest.

Effect of Genetic Variation of NAT2 on Isoniazid and SLCO1B1 and CES2 on Rifampin Pharmacokinetics in Ghanaian Children with Tuberculosis.

Isoniazid and rifampin are essential components of first-line antituberculosis (anti-TB) therapy. Understanding the relationship between genetic factors and the pharmacokinetics of these drugs could be useful in optimizing treatment outcomes, but this is understudied in children. We investigated the relationship between N-acetyltransferase type 2 (NAT2) genotypes and isoniazid pharmacokinetics, as well as that between the solute carrier organic anion transporter family member 1B1 (encoded by SLCO1B1) and carboxylesterase 2 (CES2) single nucleotide polymorphisms (SNPs) and rifampin pharmacokinetics in Ghanaian children. Blood samples were collected at times 0, 1, 2, 4, and 8 h postdose in children with tuberculosis on standard first-line therapy for at least 4 weeks. Isoniazid and rifampin concentrations were determined by a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method, and pharmacokinetic parameters were calculated using noncompartmental analysis. Genotyping of NAT2, SLCO1B1, and CES2 SNPs were performed using validated TaqMan genotyping assays. The Kruskal-Wallis test was used to compare pharmacokinetic parameters among the three genotypic groups and was followed by the Wilcoxon rank sum test for pairwise group comparisons. Genotype status inferred by the NAT2 4-SNP and 7-SNP genotyping panels identified children with a slow acetylator phenotype but not the rapid genotype. For rifampin, only the rare SLCO1B1*1b homozygous variant was associated with rifampin pharmacokinetics. Our findings suggest that NAT2 and SCLCO1B1*1b genotyping may have minimal clinical utility in dosing decisions at the population level in Ghanaian children, but it could be useful at the individual level or in populations that have a high frequency of implicated genotypes. Further studies in other populations are warranted.

Impact of SLCO1B1 Genotype on Pediatric Simvastatin Acid Pharmacokinetics.

This study investigated the impact of allelic variation in SLCO1B1, a gene encoding for the liver-specific solute carrier organic anion transporter family member 1B1 protein (SLCO1B1), on simvastatin and simvastatin acid (SVA) systemic exposure in children and adolescents. Participants (8-20 years old) with at least 1 variant SLCO1B1 c.521T>C allele (521TC, n=15; 521CC, n=2) and 2 wild-type alleles (521TT, n=15) completed a single oral dose pharmacokinetic study. At equivalent doses, SVA exposure was 6.3- and 2.5-fold greater in 521CC and TC genotypes relative to 521TT (Cmax , 2.1 ± 0.2 vs 1.0 ± 0.5 vs 0.4 ± 0.3 ng/mL; P< .0001; and AUC, 12.1 ± 0.3 vs 4.5 ± 2.5 vs 1.9 ± 1.8 ng·h/mL; P< .0001). The impact of the SLCO1B1 c.521 genotype was more pronounced in children, although considerable interindividual variability in SVA exposure was observed within genotype groups. In addition, SVA systemic exposure was negligible in 25% of pediatric participants. Further investigation of the ontogeny and genetic variation of SVA formation and SLCO1B1-mediated hepatic uptake is necessary to better understand the variability in SVA exposure in children and its clinical consequences.

Clinical Pharmacogenetic Models of Treatment Response to Methotrexate Monotherapy in Slovenian and Serbian Rheumatoid Arthritis Patients: Differences in Patient's Management May Preclude Generalization of the Models.

Objectives: Methotrexate (MTX) is the first line treatment for rheumatoid arthritis (RA), but nevertheless 30% of patients experience MTX inefficacy. Our aim was to develop a clinical pharmacogenetic model to predict which RA patients will not respond to MTX monotherapy. We also assessed whether this model can be generalized to other populations by validating it on a group of Serbian RA patients.Methods: In 110 RA Slovenian patients, data on clinical factors and 34 polymorphisms in MTX pathway were analyzed by Least Absolute Shrinkage and Selection Operator (LASSO) penalized regression to select variables associated with the disease activity as measured by Disease Activity Score (DAS28) score after 6 months of MTX monotherapy. A clinical pharmacogenetic index was constructed from penalized regression coefficients with absolute value above 0.05. This index was cross-validated and also independently validated on 133 Serbian RA patients.Results: A clinical pharmacogenetic index for prediction of DAS28 after 6 months of MTX monotherapy in Slovenian RA patients consisted of DAS28 score at diagnosis, presence of erosions, MTX dose, Solute Carrier Family 19 Member 1 (SLC19A1) rs1051266, Solute Carrier Organic Anion Transporter Family Member 1B1 (SLCO1B1) rs2306283, Thymidylate Synthase (TYMS), and Adenosine Monophosphate Deaminase 1 (AMPD1) rs17602729. It correctly classified 69% of Slovenian patients as responders or nonresponders and explained 30% of variability in DAS28 after 6 months of MTX monotherapy. Testing for validity in another population showed that it classified correctly only 22.5% of Serbian RA patients.Conclusions: We developed a clinical pharmacogenetic model for DAS28 after 6 months of MTX monotherapy in Slovenian RA patients by combining clinical and genetic variables. The clinical pharmacogenetic index developed for Slovenian patients did not perform well on Serbian patients, presumably due to the differences in patients' characteristics and clinical management between the two groups.

English

Rifampin is one of first-line drugs for the treatment of tuberculosis. In Indonesia nearly all tuberculosis patients show lower rifampin plasma concentrations possibly due to genetics. Rifampin is a substrate of the organic anion-transporting polypeptide 1B1 (OATP 1B1) encoded by the solute carrier organic anion transporter family member 1B1 (SLCO1B1). This study aimed to identify haplotype polymorphisms of tuberculosis drug transporters with an impact on clinical outcome in tuberculosis patients. Thirty-six patients from Abdul Wahab Sjahranie General Hospital, Samarinda, East Kalimantan were involved in the study. Buffy coat from patient blood samples were tested for SLCO1B1 and SLCO1B3 polymorphisms by RFLP and ARMS PCR, whereas the clinical outcome was examined based on the sputum conversion. The frequency of patients with SLCO1B1*15 haplotype was 63.9%. The SLCO1B1*15 haplotype was associated with susceptibility to failure of clinical outcome (p=0.005; RR=4.52; 95% CI: 1.22-16.64). The OATP1B1*15 haplotype revealed that the failure of clinical outcome was markedly increased compared to the three other haplotypes. These results suggest that the SLCO1B1*15 haplotype is an important predisposing factor for lower clinical outcome. Our data indicate that individualized treatment should be considered for Indonesian tuberculosis patients based on genetics characteristics of patients.

Association between a microRNA binding site polymorphism in SLCO1A2 and the risk of delayed methotrexate elimination in Chinese children with acute lymphoblastic leukemia

Organic anion-transporting polypeptide 1A2 (OATP1A2) is involved in the cellular uptake of methotrexate (MTX). Genetic variation in solute carrier organic anion transporter family member 1A2 (SLCO1A2, the coding gene of OATP1A2) has important implications for the elimination of MTX. We investigated the association between a microRNA (miRNA) binding site polymorphism (rs4149009 G > A) in the 3′-untranslated region (3′-UTR) of SLCO1A2 with the serum MTX concentrations in Chinese children with acute lymphoblastic leukemia (ALL). Genotyping for SLCO1A2 rs4149009 G > A in 141 children with ALL was performed using the Sequenom MassARRAY system. Serum MTX concentrations were determined by fluorescence polarization immunoassay. The percentages of MTX level ≥1 μmol/L at 42 h were compared among the AA, GA, and GG genotypes. The minor allele frequency observed in this study (33.0%) was significantly lower than that in the African samples reported in the 1000 Genomes Project (57.4%, P = 0.00). The incidence rate of delayed MTX elimination was significantly higher in patients with the GG genotype (23.1%) compared with the AA genotype (0.0%, P = 0.03). Bioinformatics tools predicted that the rs4149009 A allele would disrupt the putative binding sites of hsa-miR-324-3p and hsa-miR-1913. These results indicate that the rs4149009 G > A polymorphism might affect MTX pharmacokinetics by interfering with the function of miRNAs.

Immunohistochemical differentiation between chronic enteropathy associated with SLCO2A1 gene and other inflammatory bowel diseases.

Background/AimsWe recently identified recessive mutations in the solute carrier organic anion transporter family member 2A1 gene (SLCO2A1) as causative variants of chronic enteropathy associated with SLCO2A1 (CEAS). The aim of this study was to evaluate SLCO2A1 protein expression in the intestinal tissues of patients with CEAS, intestinal Behçet's disease (BD), simple ulcer (SU), and Crohn's disease (CD).MethodsImmunohistochemical staining using a polyclonal anti-SLCO2A1 antibody was performed on the resected intestinal specimens from 13 cases of CD, 9 cases of intestinal BD/SU, and 3 cases of CEAS. The extent of SLCO2A1 expression was determined by counting positively-staining vascular endothelial cells and scored as 0 (no cells), 1 (1%–30% cells), 2 (31%–60%), or 3 (>60%). The intensity of SLCO2A1 expression was scored either as 0 (negative), 1 (intermediate), or 2 (strong). The extent score and intensity score were summed for the final score of 0, 2, 3, 4, or 5.ResultsSLCO2A1 protein expression was observed in 1 of 3 cases of CEAS (33%), all 13 cases of CD (100%), and all 9 cases of BD/SU (100%). The mean final expression scores of CEAS, CD, and BD/SU were 1.6 (range, 0–5), 4.8 (range, 4–5), and 4.3 (range, 4–5), respectively. The final expression score in CEAS was significantly lower than in CD (P=0.03).ConclusionsImmunohistochemical staining of the SLCO2A1 protein is considered useful to distinguish CEAS from other inflammatory bowel diseases.

Aberrant DNA methylation of pregnane X receptor underlies metabolic gene alterations in the diabetic kidney.

Epigenetic abnormalities have been suggested to mediate metabolic memory observed in diabetic complications. We have shown that epigenetic alterations may induce persistent phenotypic changes in the proximal tubules of the diabetic kidneys. In this study, we show that pregnane X receptor (PXR), a xenobiotic nuclear receptor, is epigenetically altered and upregulated and may have a possible function in the diabetic kidney. PXR has been shown to play a critical role in metabolic changes in obesity and diabetes; however, its distribution and function in the kidney are unknown. In the normal kidney, Pxr was selectively expressed in the proximal tubular cells with demethylation in the promoter DNA. In db/db mice, significant increases in Pxr mRNA, further demethylation of DNA, and stimulatory histone marks in the promoter were observed. Epigenetic changes are likely to play a causative role in PXR induction, since a DNA methyltransferase inhibitor increased PXR mRNA in cultured human proximal tubular cells. Administration of a PXR agonist increased mRNA levels of solute carrier organic anion transporter family member 2B1 ( Slco2b1), a xenobiotic transporter; response gene to complement 32 ( Rgc32), a molecule known to exert fibrotic effects in the kidney; and phosphoenolpyruvate carboxykinase 1 ( Pck1), a gluconeogenic enzyme in the kidney. The expressions of these genes were inhibited by PXR small interfering RNA in cultured proximal tubular cells. Increased mRNA levels of Slco2b1, Rgc32, and Pck1 were also observed in the kidney of db/db mice. These data indicate that PXR is upregulated in the diabetic kidney with aberrant epigenetic modifications and may modulate the course of diabetic kidney disease through the activation of these genes.

Roles of Organic Anion Transporting Polypeptide 2A1 (OATP2A1/SLCO2A1) in Regulating the Pathophysiological Actions of Prostaglandins.

Solute carrier organic anion transporter family member 2A1 (OATP2A1, encoded by the SLCO2A1 gene), which was initially identified as prostaglandin transporter (PGT), is expressed ubiquitously in tissues and mediates the distribution of prostanoids, such as PGE2, PGF2α, PGD2 and TxB2. It is well known to play a key role in the metabolic clearance of prostaglandins, which are taken up into the cell by OATP2A1 and then oxidatively inactivated by 15-ketoprostaglandin dehydrogenase (encoded by HPGD); indeed, OATP2A1-mediated uptake is the rate-limiting step of PGE2 catabolism. Consequently, since OATP2A1 activity is required for termination of prostaglandin signaling via prostanoid receptors, its inhibition can enhance such signaling. On the other hand, OATP2A1 can also function as an organic anion exchanger, mediating efflux of prostaglandins in exchange for import of anions such as lactate, and in this context, it plays a role in the release of newly synthesized prostaglandins from cells. These different functions likely operate in different compartments within the cell. OATP2A1 is reported to function at cytoplasmic vesicle/organelle membranes. As a regulator of the levels of physiologically active prostaglandins, OATP2A1 is implicated in diverse physiological and pathophysiological processes in many organs. Recently, whole exome analysis has revealed that recessive mutations in SLCO2A1 cause refractory diseases in humans, including primary hypertrophic osteoarthropathy (PHO) and chronic non-specific ulcers in small intestine (CNSU). Here, we review and summarize recent information on the molecular functions of OATP2A1 and on its physiological and pathological significance.

Identification of mutations in the prostaglandin transporter gene SLCO2A1 and phenotypic comparison between two subtypes of primary hypertrophic osteoarthropathy (PHO): A single-center study

Primary hypertrophic osteoarthropathy (PHO) is an inherited disease characterized by digital clubbing, periostosis, and pachydermia. Based on two causative genes, hydroxyprostaglandin dehydrogenase (HPGD) and solute carrier organic anion transporter family member 2A1 (SLCO2A1), PHO is categorized into two subtypes: hypertrophic osteoarthropathy, primary, autosomal recessive 1 (PHOAR1) and hypertrophic osteoarthropathy, primary, autosomal recessive 2 (PHOAR2). In this study, we summarized the clinical manifestations and analyzed SLCO2A1 gene in 23 PHOAR2 patients in our center. As a result, 18 patients displayed complete phenotypes of PHO with digital clubbing, periostosis, and pachydermia. 29 mutations were found in total, and 22 of them were novel mutations including 13 missense, three nonsense, four deletion, one frame-shift and one splicing site mutations. Compared with nine PHOAR1 patients we previously reported, PHO patients with SLCO2A1 mutations were all male and presented with a later onset age. Peptic ulcers and myelofibrosis occurred only in PHOAR2 patients. The urinary level of prostaglandin E2 metabolite (PGEM) is significantly higher in PHOAR2 patients than that in PHOAR1 group. In conclusion, this study was the largest cohort to date to summarize PHOAR2 patients and to assess the phenotypic difference between two subtypes of PHO. The difference of urinary PGEM concentration between two subtypes is helpful for the differential diagnosis of PHO.

Fusobacterium nucleatum in gastroenterological cancer: Evaluation of measurement methods using quantitative polymerase chain reaction and a literature review.

The human microbiome Fusobacterium nucleatum, which primarily inhabits the oral cavity, causes periodontal disease and has also been implicated in the development of colorectal cancer. However, whether F. nucleatum is present in other gastroenterological cancer tissues remains to be elucidated. The present study evaluated whether quantitative polymerase chain reaction (qPCR) assays were able to detect F. nucleatum DNA and measure the quantity of F. nucleatum DNA in esophageal, gastric, pancreatic and liver cancer tissues. The accuracy of the qPCR assay was determined from a calibration curve using DNA extracted from cells from the oral cavity. Formalin-fixed paraffin-embedded (FFPE) tumor tissues from 20 patients with gastroenterological [esophageal (squamous cell carcinoma), gastric, colorectal, pancreatic and liver] cancer and 20 matched normal tissues were evaluated for F. nucleatum DNA content. The cycle threshold values in the qPCR assay for F. nucleatum and solute carrier organic anion transporter family member 2A1 (reference sample) decreased linearly with the quantity of input DNA (r2>0.99). The F. nucleatum detection rate in esophageal, gastric and colorectal cancer tissues were 20% (4/20), 10% (2/20) and 45% (9/20), respectively. F. nucleatum was not detected in liver and pancreatic cancer tissues. The qPCR results from the frozen and FFPE tissues were consistent. Notably, F. nucleatum was detected at a higher level in superficial areas compared with the invasive areas. F. nucleatum in esophageal, gastric and colorectal cancer tissues was evaluated by qPCR using FFPE tissues. F. nucleatum may be involved in the development of esophageal, gastric and colorectal cancer.

Genetic Polymorphisms of SLCO1B1, CYP2E1 and UGT1A1 and Susceptibility to Anti-Tuberculosis Drug-Induced Hepatotoxicity: A Chinese Population-Based Prospective Case–Control Study

Drug transporters and drug-metabolizing enzymes have been linked to drug-induced hepatotoxicity. Solute carrier organic anion transporter family member 1B1 (SLCO1B1), cytochrome P450 2E1 (CYP2E1), and UDP glucuronosyltransferase 1A1 (UGT1A1) were selected as candidate genes to explore their association with susceptibility to anti-tuberculosis drug-induced hepatotoxicity (ATDH). Thirty-four tag single nucleotide polymorphisms (tagSNPs) in SLCO1B1, CYP2E1, and UGT1A1 with 10-kb expansion up- and down-stream were genotyped in 461 patients with ATDH and 466 patients without ATDH in a prospective 1:1 matched case-control study. The frequencies and distributions of genotypes and haplotypes were compared between the groups using three genetic models (dominant, recessive, and additive) to identify associations with susceptibility to ATDH. Patients with the rs4149034 G/A, rs1564370 G/C, and rs2900478 T/A genotypes of SLCO1B1 had a significantly lower risk of ATDH, while those carrying the rs2417957 T/T and rs4149063 T/T genotypes had an increased risk. The rs4148323 A/A genotype of UGT1A1 was found to significantly reduce the risk of ATDH. Haplotype analysis showed the TGTG, TTTC, and GTTC haplotypes of SLCO1B1 were associated with an increased ATDH risk, whereas the GACC haplotype was related to a reduced risk. The ATG haplotype of UGT1A1 reduced the risk of ATDH. Moreover, treatment outcomes in tuberculosis patients were further affected by genetic variants of SLCO1B1. Genetic polymorphisms of SLCO1B1 and UGT1A1 were found to be associated with susceptibility to ATDH. Molecular identification of susceptibility genes provides a theoretical foundation for predicting the likelihood of ATDH and predicting treatment outcomes in tuberculosis patients.

Key Role for the Organic Anion Transporters, OAT1 and OAT3, in the in vivo Handling of Uremic Toxins and Solutes

In vitro data indicates that the kidney proximal tubule (PT) transporters of uremic toxins and solutes (e.g., indoxyl sulfate, p-cresol sulfate, kynurenine, creatinine, urate) include two “drug” transporters of the organic anion transporter (OAT) family: OAT1 (SLC22A6, originally NKT) and OAT3 (SLC22A8). Here, we have examined new and prior metabolomics data from the Oat1KO and Oat3KO, as well as newly obtained metabolomics data from a “chemical double” knockout (Oat3KO plus probenecid). This gives a picture of the in vivo roles of OAT1 and OAT3 in the regulation of the uremic solutes and supports the centrality of these “drug” transporters in independently and synergistically regulating uremic metabolism. We demonstrate a key in vivo role for OAT1 and/or OAT3 in the handling of over 35 uremic toxins and solutes, including those derived from the gut microbiome (e.g., CMPF, phenylsulfate, indole-3-acetic acid). Although it is not clear whether trimethylamine-N-oxide (TMAO) is directly transported, the Oat3KO had elevated plasma levels of TMAO, which is associated with cardiovascular morbidity in chronic kidney disease (CKD). As described in the Remote Sensing and Signaling (RSS) Hypothesis, many of these molecules are involved in interorgan and interorganismal communication, suggesting that uremia is, at least in part, a disorder of RSS.

The Importance of Steroid Uptake and Intracrine Action in Endometrial and Ovarian Cancers.

Endometrial and ovarian cancers predominately affect women after menopause, and are more frequently observed in developed countries. These are considered to be hormone-dependent cancers, as steroid hormones, and estrogens in particular, have roles in their onset and progression. After the production of estrogens in the ovary has ceased, estrogen synthesis occurs in peripheral tissues. This depends on the cellular uptake of estrone-sulfate and dehydroepiandrosterone-sulfate, as the most important steroid precursors in the plasma of postmenopausal women. The uptake through transporter proteins, such as those of the organic anion-transporting polypeptide (OATP) and organic anion-transporter (OAT) families, is followed by the synthesis and action of estradiol E2. Here, we provide an overview of the current understanding of this intracrine action of steroid hormones, which depends on the availability of the steroid precursors and transmembrane transporters for precursor uptake, along with the enzymes for the synthesis of E2. The data is also provided relating to the selected transmembrane transporters from the OATP, OAT, SLC51, and ABC-transporter families, and the enzymes involved in the E2-generating pathways in cancers of the endometrium and ovary. Finally, we discuss these transporters and enzymes as potential drug targets.

Pachydermoperiostosis of the complete type: A novel missense mutation c.101T > C in the SLCO2A1 gene

We report on a rare case of pachydermoperiostosis (PDP) in a 25-year-old male who was admitted to our hospital because of enlargement of fingers and toes. Through examination, we found some typical features on the patient including finger clubbing, periostosis, pachydermia, and cutis verticis gyrata (CVG). But laboratory tests were almost within normal ranges, which ruled out rheumatic arthritis, osteopulmonary arthropathy, thyroid acropathy, and acromegaly. Then, we diagnosed this case as PDP, which was confirmed by gene sequencing. The pathogenesis is concerned with abnormal rise of the level of PGE2 that results from the solute carrier organic anion transporter family member 2A1 (SLCO2A1) gene defect. Meanwhile, we found a novel missense mutation c.101T > C of the SLCO2A1 gene in the patient with PDP.

Chronic Enteropathy Associated With SLCO2A1 Gene [CEAS]-Characterisation of an Enteric Disorder to be Considered in the Differential Diagnosis of Crohn's Disease.

Small intestinal ulcers include mucosal damage caused by drugs, particularly nonsteroidal anti-inflammatory drugs [NSAIDs], infectious diseases, and idiopathic inflammatory bowel disease. Previously, a group of Japanese investigators reported an unusual and uncommon type of enteritis and referred to the condition as chronic nonspecific multiple ulcers of the small intestine [CNSU]. CNSU is characterised by chronic blood and protein loss through persistent small intestinal ulcers. Recently, four candidate mutations in the solute carrier organic anion transporter family, member 2A1 [SLCO2A1] gene, encoding a prostaglandin transporter, were identified by whole-exome sequencing in patients with CNSU. However, because the name 'CNSU' was somewhat ambiguous, the more appropriate nomenclature of 'chronic enteropathy associated with the SLCO2A1 gene' [CEAS] has been suggested. CEAS ulcers are characterised by multiple, circular or eccentric oblique, shallow lesions with discrete margins. The most frequently affected site of CEAS is the ileum, in contrast to 'cryptogenic multifocal ulcerous stenosing enteritis [CMUSE]', for which the most frequent site is the jejunum. Impaired prostaglandin utilisation is thought to cause the small intestinal mucosal damage observed in CEAS, CMUSE, and NSAID-induced enteropathy. This review article focuses on endoscopic and clinical features of genetically diagnosed CEAS, accumulated in a nationwide survey, and illustrates the observations in the format of an atlas.

Primary hypertrophic osteoarthropathy due to a novel SLCO2A1 mutation masquerading as acromegaly

SummaryA 20-year-old man with an 8-year history of progressive enlargement of his hands and feet, coarsening facial features, painful joints and thickened, oily skin was referred for investigation of acromegaly. On examination, the subject was of normal height and weight. He had markedly increased skin thickness around the forehead, eyelids and scalp with redundant skin folds. Bilateral painful knee swelling was accompanied by enlargement of the extremities, and his fingers were markedly clubbed. Routine hematological, biochemical and hormonal blood tests, including GH and IGF-1 were normal. The clinical picture suggested primary hypertrophic osteoarthropathy (PHOA) rather than acromegaly and radiological studies were supportive of this, demonstrating increased subperiosteal bone formation and increased bone density and cortical thickening. There was widespread joint disease, with narrowing of joint spaces, whereas the knees demonstrated effusions and calcification. A skull X-ray revealed calvarial hyperostosis and a normal sellar outline. Family history was negative. Genetic studies were performed on peripheral blood leukocyte DNA for mutations in the two genes associated with PHOA, 15-hydroxyprostaglandin dehydrogenase (HPGD; OMIM: 601688) and solute carrier organic anion transporter family member 2A1 (SLCO2A1; OMIM: 601460). The sequence of HPGD was normal, whereas the subject was homozygous for a novel pathological variant in SLCO2A1, c.830delT, that predicted a frameshift and early protein truncation (p.Phe277Serfs*8). PHOA, also known as pachydermoperiostosis, is a rare entity caused by abnormal prostaglandin E2 metabolism, and both HPGD and SLCO2A1 are necessary for normal prostaglandin E2 handling. High prostaglandin levels lead to bone formation and resorption and connective tissue inflammation causing arthropathy, in addition to soft tissue swelling.Learning points:The differential diagnosis of enlarged extremities, coarsened facial features, skin changes and increased sweating in suspected acromegaly is quite limited and primary hypertrophic osteoarthropathy (PHOA) is one of the few conditions that can mimic acromegaly at presentation.PHOA is not associated with abnormalities in GH and IGF-1 secretion and can be readily differentiated from acromegaly by hormonal testing.Clubbing in the setting of diffuse enlargement of joints and extremities in addition to skin changes should alert the physician to the possibility of PHOA, as clubbing is not a usual feature of acromegaly. Underlying causes of secondary hypertrophic osteoarthroapthy (e.g. bronchial neoplasia) should be considered.PHOA is a very rare condition caused by abnormalities in prostaglandin metabolism and has two known genetic causes (HPGD and SLCO2A1 mutations). SLCO2A1 gene mutations lead usually to autosomal recessive PHOA; fewer than 50 SLCO2A1 mutations have been described to date and the current case is only the second in a Hispanic patient.Treatment of primary hypertrophic osteoarthropathy is focused on the management of joint pain usually in the form of non-steroidal anti-inflammatory drug therapy.

Solute carrier organic anion transporter family member 4A1 (SLCO4A1) as a prognosis marker of colorectal cancer.

Solute carrier organic anion transporter family member 4A1 (SLCO4A1) is involved in the transport of various compounds, including sugars, bile salts, organic acids, metal ions, amine compounds, and estrogen. SLCO4A1 is highly expressed in several cancers and a gender bias has been observed in colorectal cancer (CRC). We investigated SLCO4A1 expression, its prognostic value in patients with CRC, and its role in CRC cell proliferation and metastasis. SLCO4A1 expression was assessed by immunohistochemistry (IHC) on specimens from 84 patients with CRC. The association of SLCO4A1 expression with clinicopathological features was examined. To confirm the biological role of SLCO4A1 in CRC, four CRC cell lines expressing SLCO4A1 were used and SLCO4A1 expression was knocked down by siRNA. Cell proliferation, MTT, migration, invasion, and semisolid agar colony formation assays were performed. SLCO4A1 was overexpressed in 32% of the CRC samples. SLCO4A1 overexpression and pathologic T stage were independent prognostic factors of decreased survival (P = 0.021). Kaplan-Meier analysis indicated a decreased cumulative survival for patients highly expressing SLCO4A1 compared to patients showing low SLCO4A1 expression (Log-rank test, P = 0.025). In cell lines, SLCO4A1 knockdown resulted in a significant decrease of viability, invasion, and migration when compared to control cells. Semisolid colony formation assay indicated that SLCO4A1-knocked down cells presented poor carcinogenic abilities compared to control cells. SLCO4A1 may be a valuable marker of poor prognostic for CRC. Furthermore, SLCO4A1 plays an important role in CRC cell proliferation, migration, invasion, and carcinogenesis.