Low expression of SLC22A1 is associated with a poor prognosis of hepatocellular carcinoma: analysis of 303 patients / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the association between SLC22A1 expression and the outcomes of hepatocellular carcinoma (HCC) patients.</p><p><b>METHODS</b>A tissue microarray of 303 HCC and matched adjacent noncancerous liver tissues (ANLTs) were constructed. The expression of SLC22A1 was tested by immunohistochemistry (IHC) and scored by two pathologists according to a 12-score scale (a score>6 was defined as high expression, and a score≤6 as low expression). The correlation of SLC22A1 expression with the clinicopathological features and the patients' outcome was analyzed.</p><p><b>RESULTS</b>All the ANLTs had a IHC score of 12, as compared to only 29 (9.6%) of the HCC tissues. The patients were divided into 2 groups based on the IHC scores: 59% (180/303) in low expression group and 41% (123/303) in high expression group. The disease-free survival (DFS) rates and overall survival (OS) rates were significantly lower in low SLC22A1 expression group than in the high expression group. The 1-, 3-, and 5-year DFS rates were 43%, 31% and 27% in the low expression group, and were 58%, 47% and 43% in the high expression group, respectively. The 1-, 3-, and 5-year OS rates were 66%, 38% and 32% in low expression group, and were 80%, 57% and 50% in the high expression group, respectively. A low expression of SLC22A1 was positively correlated with the tumor diameter, BCLC stage, tumor differentiation, and AFP levels (P<0.05), and was an independent predictor of poor overall survival (HR=1.454; 95% CI, 1.050-2.013).</p><p><b>CONCLUSIONS</b>Down-regulation of SLC22A1 is a malignant feature and a potential prognostic marker of HCC.</p>

Efectividad de la metformina en pacientes con diabetes tipo II según variantes en el gen SLC22A1 / Effectiveness of Metformin in patients with type II diabetes related to variants in the SLC22A1 gene / Eficácia de Metformina em doentes com diabetes tipo II, relacionado com variantes do gene SLC22A1

La diabetes mellitus tipo II (DM II) es una enfermedad que afecta una gran cantidad de individuos. Un medicamento empleado en el tratamiento de los pacientes es la metformina. Este medicamento es transportado al interior de los hepatocitos por un transportador codificado por el gen SLC22A1. Variantes en el gen con actividad reducida pueden disminuir la cantidad de metformina disponible en el hígado y reducir la respuesta terapéutica. Se propuso evaluar diferentes parámetros bioquímicos en relación a la dosis de metformina y la presencia de variantes en el transportador. Se estudiaron 103 pacientes mayores de 18 años con diagnóstico de DM II, tratados con 1700 mg/día de metformina por más de 6 meses. Se analizaron 5 polimorfismos en el gen SLC22A1, glucemia, HbA1c, función hepática, perfil lipídico y renal. Los niveles de HbA1c y de glucemia fueron más elevados en los pacientes que presentaban los polimorfismos R61C, G401S, M420del y G465R aunque la diferencia fue estadísticamente significativa sólo para la HbA1c en los pacientes que presentaban las variantes M420del y G465R (p=0,0273 y 0,0018, respectivamente). La presencia de polimorfismos con actividad reducida en el gen SLC22A1 afecta los niveles de glucemia y de HbA1c en pacientes con DM II cuando son tratados con metformina.

Diabetes mellitus type II (DM II) is a disease that affects a large number of individuals. One of the drugs used for the treatment is metformin. Metformin is delivered into hepatocytes by a transporter encoded by the SLC22A1 gene. Gene variants with reduced activity may decrease the amount of metformin available in the liver and reduce the therapeutic response. Various biochemical parameters were evaluated in relation to the metformin dose and the presence of transporter variants. A total of 103 patients older than 18 diagnosed with DM II who were treated with 1700 mg/day of metformin for more than six months were studied. Five polymorphisms in the SLC22A1 gene were analyzed as well as glycemia, HbA1c level, liver function, and lipid and kidney profiles. HbA1c and glycemia levels were higher in patients with the R61C, G401S, M420del and G465R polymorphisms; although the difference was statistically significant only for HbA1c in patients with the M420del and G465R variants (p=0.0273 and 0.0018, respectively). Polymorphisms with reduced activity in the SLC22A1 gene affect blood glucose levels and HbA1c in patients with DM II when they are treated with metformin.

O diabetes mellitus tipo II (DM II) é uma doença que afeta uma grande quantidade de indivíduos. Um medicamento utilizado no tratamento dos doentes é a metformina. Esse medicamento é transportado no interior dos hepatócitos por um transportador codificado pelo gene SLC22A1. Variantes no gene com atividade reduzida podem diminuir a quantidade de Metformina disponível no fígado e reduzir a resposta terapêutica. Propôs-se avaliar diferentes parâmetros bioquímicos em relação à dose da metformina e à presença de variantes no transportador. Foram estudados 103 pacientes maiores de 18 anos com diagnóstico de DM II tratados com 1700 mg/dia de metformina por mais de 6 meses. Foram analisados 5 polimorfismos no gene SLC22A1; glicemia, HbA1c, função hepática, perfil lipídico e renal. Os níveis de HbA1c e de glicemia foram superiores em doentes que apresentavam os polimorfismos R61C, G401S, M420del e G465R; embora a diferença seja estatisticamente significativa apenas para o HbA1c nos doentes que apresentavam as variantes M420del e G465R (p=0,0273 e 0,0018; respectivamente). A presença de polimorfismos com atividade reduzida no gene SLC22A1 afeta os níveis da glicemia e do HbA1c em doentes com DM II quando são tratados com metformina.

Estudo da expressão dos genes ABCB1 e SLC22A1 e sua relação com marcadores de resposta ao mesilato de imatinibe em pacientes com leucemia mieloide crônica / Study of the expression of SLC22A1 and ABCB1 genes and their relationship with markers of response to imatinib mesylate in patients with chronic myeloid leukemia

A leucemia mieloide crônica (LMC) é uma expansão clonal da célula tronco hematopoética, traduzindo-se por hiperplasia mieloide, leucocitose, neutrofilia, basofilia e esplenomegalia. O cromossomo Filadélfia é característico da doença, sendo produto da translocação t(9:22)(q34;q11), resultando na fusão dos genes ABL e BCR. Esta fusão gera um gene híbrido que codifica uma proteína com elevada atividade tirosinoquinase e tem um papel central na patogenia da LMC. O mesilato de imatinibe (MI) é um derivado da fenilaminopirimidina que inibe a proteína tirosinoquinase BCR-ABL1 in vitro e in vivo. O MI interage com transportadores de membrana de influxo, como o organic carion solute carrier 22 ,member 1 (SLC22A1,hOCT1); e de efluxo, como ATP binding cassette B1 (ABCB1, MDR1, P-gp). Os polimorfismos ABCB1 c.1236C>T, C.3435C>T e c.2677G>T/A têm sido associados com a alteração da função da P-gp. Este estudo teve por objetivo investigar a relação da expressão do RNAm de ABCB1 e SLC22A1 com marcadores de resposta ao tratamento com MI e avaliar a atividade funcional da P-gp em células mononucleares de pacientes com diferentes haplótipos para os polimorfismos ABCB1 c.1236C>T, c.3435C>T e c.2677G>T/A. Foram incluídos 118 pacientes com LMC para o estudo da expressão do RNAm de SLC22A1 e ABCB1 e para o estudo da atividade da P-gp foram selecionados 28 pacientes de acordo com os haplótipos dos polimorfismos ABCB1 c.1236C>T, c.3435C>T e c.2677G>T/A. Para o estudo da expressão do RNAm de SLC22A1 e ABCB1 foram constituídos dois grupos: Grupo 1 com 70 pacientes com resposta citogenética completa com a dose padrão de MI (400 mg/dia de MI) em até 18 meses e, Grupo 2 com 48 pacientes sem resposta citogenética completa com a dose inicial de 400 mg/dia de MI ou que perderam esta resposta ao longo do tratamento. Para o estudo da atividade funcional da P-gp, dos 118 pacientes incluídos, foram selecionados 10 pacientes que apresentaram o haplótipo 1236CC/3435CC/2677GG, 10 pacientes que apresentaram o haplótipo 1236CT/3435CT/2677GT e 8 pacientes que apresentaram o haplótipo 1236TT/3435TT/2677TT. A resposta ao tratamento foi avaliada segundo os critérios da European LeukemiaNet. Amostras de sangue foram obtidas para: quantificação de BCR-ABL1, extração do RNAm total, análise citogenética de banda G, dosagem da concentração plasmática de MI e análise da atividade e expressão da P-gp. A análise da expressão dos genes ABCB1 e SLC22A1 foi feita por PCR em tempo real, a análise da atividade e expressão da P-gp foram feitas por citometria de fluxo e a dosagem da concentração plasmática de MI foi realizada por eletroforese capilar. Resultados: A expressão de ABCB1 e SLC22A1 foi analisada nos 118 pacientes incluídos e foi similar entre os grupos de resposta. A elevada expressão do gene SLC22A1 foi associada àqueles pacientes que alcançaram a resposta molecular maior (RMM) no grupo respondedor (P=0,009). Não houve associação entre a expressão de ABCB1 e a resposta ao MI. Nenhum dos genes foi associado à resposta molecular completa (RMC). No estudo da atividade da P-gp foi observada uma maior atividade nos pacientes que apresentavam o haplótipo 1236CC/3435CC/2677GG quando comparado àqueles que possuíam o haplótipo com alelo mutado. Não houve diferença na expressão do RNAm dos genes SLC22A1 e ABCB1, expressão da P-gp e concentração plasmástica de MI entre os grupos de haplótipos. Os pacientes que não alcançaram a RMM apresentaram uma maior taxa de efluxo mediado pela P-gp quando comparado aos indivíduos que alcançaram esta resposta (64,7% vs. 45,7%; P=0,001). Os indivíduos que alcançaram a RMM e RMC apresentaram maior mediana de expressão do gene SLC22A1. Os pacientes sem RMM apresentaram menor concentração plasmática de MI quando comparados aos que alcançaram esta resposta (0,51 µg/mL vs. 1,42 µg/mL; P=0,001). Não foi observada associação entre a concentração plasmática de MI e a RMC. Em conclusão os pacientes respondedores a dose padrão de 400mg/dia de MI e que alcançaram a RMM apresentam maior expressão de RNAm de SLC22A1 e os portadores dos haplótipos 1236CT/3435CT/2677GT e 1236TT/3435TT/2677TT exibem menor efluxo mediado pela P-gp apresentando maior frequência de RMM

Chronic myeloid leukemia (CML) is a clonal expansion of hematopoietic stem cell, translating into myeloid hyperplasia, leukocytosis, neutrophilia, basophilia and splenomegaly. The Philadelphia chromosome is characteristic of the disease, being the product of the translocation t(9:22)( q34,q11), resulting in the fusion of the BCR and ABL genes. This fusion generates a hybrid gene that encodes a protein with elevated tyrosine kinase activity and plays a central role in the pathogenesis of CML. Imatinib mesylate (IM) is a derivative of fenilaminopirimidine that inhibits BCR-ABL1 fusion protein tyrosine kinase in vitro and in vivo. IM interacts with uptake membrane transporters, such as cation organic solute carrier 22, member 1 (SLC22A1, hOCT1) and efflux as ATP binding cassette B1 (ABCB1, MDR1,P-gp). ABCB1 polymorphisms c.1236C>T,c.3435C>T and c.2677G>T/A have been associated with altered function of P-gp. This study aimed to investigate the relationship between mRNA expression of ABCB1 and SLC22A1 with markers of response to treatment with IM and evaluate the functional activity of P-gp in mononuclear cells of patients with different haplotypes for ABCB1 c.1236C>T, c.3435C>T and c.2677G>T/A polymorphisms. This study included 118 patients with CML to study the mRNA expression of SLC22A1 and ABCB1 and to study the P-gp activity, 28 patients were selected according to the haplotypes of ABCB1 c.1236C>T, c.3435C>T and c.2677G>T/A polymorphisms. To study the mRNA expression of SLC22A1 and ABCB1, two groups were constituted: Group 1 with 70 patients with a complete cytogenetic response with standard-dose IM (400 mg/day) in 18 months, and group 2 with 48 patients without complete cytogenetic response with the initial dose of IM (400 mg/day) or have lost this response during treatment. To study the P-gp functional activity, 10 patients with haplotype 1236CC/3435CC/2677GG, 10 patients with haplotype 1236CT/3435CT/2677GT and 8 patients with haplotype 1236TT/3435TT/2677TT were enrolled. Treatment response was assessed according to European LeukemiaNet criteria. Blood samples were obtained for: quantification of BCR-ABL1, mRNA extraction, G band cytogenetic analysis, measurement of IM plasma levels and P-gp activity and expression. The ABCB1 and SLC22A1 gene expression analysis was made by real-time PCR, analysis of P-gp activity and protein expression were performed by flow cytometry and determination of plasma Levels of IM was performed by capillary electrophoresis. Results: Expression of ABCB1 and SLC22A1 were analyzed in 118 patients included and was similar between the response groups. Higher expression of the SLC22A1 gene was associated with those patients who achieved a major molecular response (MMR) in the responder group (P=0.009). There was no association between ABCB1 expression and IM response. None of the studied genes was associated with complete molecular response (CMR). In the study of P-gp activity we observed greater activity mediated by P-gp in patients with 1236CC/3435CC/2677GG haplotype when compared to those with the mutated allele. There was no difference in mRNA expression of SLC22A1 and ABCB1 genes, P-gp expression and IM plasma levels between haplotypes groups. Patients who did not achieve MMR showed a higher rate of efflux mediated by P-gp compared to individuals who did achieve this response (64.7% vs. 45.7%, P=0.001). Individuals who achieved MMR and CMR had higher median of SLC22A1 expression. Patients without MMR had lower IM plasma levels compared with those who achieved this response (0.51 µg/mL vs. 1.42 µg/mL, P=0.001). No association was observed between IM plasma levels and CMR. In conclusion patients responders to standard dose of IM (400 mg/day) and who achieved MMR have higher SLC22A1 mRNA expression and the carriers of 1236CT/3435CT/2677GT 1236TT/3435TT/2677TT haplotypes exhibit lower efflux mediated by P-gp with higher frequency of MMR

Study on imatinib trough concentration, efficacy and their relation in chronic myelocytic leukemia / 中华血液学杂志

<p><b>OBJECTIVE</b>To determine plasma imatinib concentration, intracellular imatinib concentration, and hOCT1 and ABCB1 mRNA expression in bone marrow cells of CML patients to further evaluate the potential usefulness of these measures as markers of imatinib efficacy and their clinical relationships.</p><p><b>METHODS</b>Eighty CML patients in chronic phase receiving imatinib were enrolled in this study, including 56 males and 24 females with a median age of 39.5 (6 - 76) years. Imatinib was administered at a median dose of 400 (200 - 800) mg/d orally per day with a median course of 24 (3 - 90) months. The intracellular imatinib concentrations in bone marrow cells of 28 patients were simultaneously determined. Real-time quantitative PCR with a taqman probe was used to assess hOCT1 and ABCB1 mRNA expression on bone marrow cells of 36 patients. Imatinib trough concentration was determined by high-performance liquid chromatography-tandem mass spectrometry with a detectability of 2 - 10 000 µg/L. Serum α1-acid glycoprotein (AGP) was measured by immune turbidimetry on a BNProspec protein analyzer (Dade Behring, USA). All patients were divided into MMR, CCyR, PCyR or drug-resistant groups according to response.</p><p><b>RESULTS</b>Plasma imatinib trough concentration of 80 patients was (1274.1 ± 559.1) (109.0 - 3400.0) µg/L. The plasma imatinib trough concentration of 59 (73.8%) patients with a dose of 400 mg/d was (1252.0 ± 569.5) (109 - 3400) µg/L, including 37 (62.7%) patients with concentrations of more than 1000 µg/L and 9 (15.2%) patients more than 800 µg/L. Plasma imatinib trough concentration in the MMR group \[(1531.9 ± 634.1) µg/L\] was significant higher than in the PCyR \[(812.8 ± 480.3) µg/L\] or drug-resistant group \[(875.2 ± 243.1) µg/L\] (P < 0.05). Plasma imatinib trough concentration in the CCyR group \[(1288.4 ± 498.2) µg/L\] was significant higher than in the PCyR group (P = 0.027). There was no significant difference between CCyR and MMR groups with regard to plasma imatinib trough concentration (P = 0.136). The intracellular imatinib concentration in bone marrow cells in the CCyR group \[12.6 (2.4 - 90.4) µg/L\] was significantly higher than drug-resistant \[6.6 (2.6 - 111.0) µg/L\] or PCyR \[2.7 (2.4 - 4.7) µg/L\] groups (P = 0.013). The hOCT1 mRNA expression on bone marrow cells in the CCyR group \[25.9(0.7 - 123.9) × 10(-5)\] was significantly higher than in drug-resistant \[7.8 (2.5 - 33.5) × 10(-5)\] or PCyR \[4.2 (1.4 - 11.9) × 10(-5)\] groups (P = 0.036). The ABCB1 mRNA expression on bone marrow cells in drug-resistant group \[136.7 (15.0 - 1604.9) × 10(-5)\] was significantly higher than in CCyR \[129.1 (12.9 - 783.3) × 10(-5)\] or PCyR \[34.4 (2.2 -108.2) × 10(-5)\] groups (P = 0.013). Plasma imatinib trough concentration was positively correlated with AGP (r = 0.446, P = 0.000) or dose (r = 0.346, P = 0.002). There were no significant correlations between plasma imatinib trough concentration and height, weight or body surface area (P > 0.05). There were no significant differences among different courses with regard to plasma imatinib trough concentration (P > 0.05).</p><p><b>CONCLUSION</b>Clinical responses in CML patients were correlated with plasma and intracellular imatinib trough concentrations. Imatinib concentration was regulated by AGP and the activities of hOCT1 and ABCB1.</p>

Genetic analysis of OCT1 gene polymorphisms in an Indian population.

BACKGROUND: Genetic variants of the organic cation transporter (OCT1) gene could influence interindividual variation in clinical response to metformin therapy. The genetic basis for the single-nucleotide polymorphism (SNP) of OCT1 gene has been established in other populations, but it remains to be elucidated in the Indian population. This study is focused on OCT1 gene variants rs2282143 (P341L, 1022C>T), rs628031 (M408V, 1222A>G) and rs622342 (1386C>A) frequency distributions in the South Indian Tamilian population. MATERIALS AND METHODS: A total of 112 unrelated healthy subjects of South Indian Tamilian origin, aged 18–60 years, of either sex were recruited for the study. Genotyping was determined using the quantitative real time-polymerase chain reaction and polymerase chain reaction followed by restriction fragment length polymorphism methods. RESULTS: Allele frequencies of rs2282143, rs628031and rs622342 polymorphisms were 8.9%, 80.3% and 24.5%, respectively. Interethnic differences in the genotype and allele frequencies of OCT1 gene polymorphism were observed when compared with other major populations. The SNPs rs2282143, T allele and rs628031, G allele were more common in Asians (5.5–16.8% and 76.2–81%) and African Americans (8.2% and 73.5%) than in Caucasians (0–2% and 57.4–60%). CONCLUSION: This is the first time the frequency of OCT1 gene polymorphism was determined in the Indian population, and is similar to the frequencies observed in African-Americans and other Asian populations but different from those in Caucasians. The data observed in this study would justify further pharmacogenetic studies to potentially evaluate the role of OCT1 gene polymorphism in the therapeutic efficacy of metformin.

Influence of hOCT1 polymorphism on imatinib mesylate effectiveness in chronic myelogenous leukemia patients / 中华血液学杂志

<p><b>OBJECTIVE</b>To explore the correlation between hOCT1 polymorphism and imatinib mesylate (IM) effectiveness in chronic myelogenous leukemia(CML) patients, and to provide for the clinical individual personalized therapy.</p><p><b>METHODS</b>Fifty-three CML and 23 non-CML patients were enrolled in this study. Blood or bone marrow samples were collected. Amplification refractory mutation system (ARMS)-polymerase chain reaction was used to amplify the polymorphisms gene segment of hOCT1-P283L, R287G and M408V and their frequencies were statistically analysed. With clinical outcomes, the correlation between hOCT1 polymorphism and IM effectiveness in CML was analyzed.</p><p><b>RESULTS</b>(1) For 74 Han Chinese, the allele frequencies of hOCT1-P283L, R287G and M408V were 39.86%, 29.05% and 45.27%, respectively. (2) The genotypes of hOCT1-P283L, R287G and M408V in 2 Tibetan Chinese were CC, CC, AG and CC, CG, AG, respectively. (3) In the CML patients with IM optimal response, the frequencies of 283T and 287G allele were predominant (P<0.05). No significant difference was found in the frequency distribution of hOCT1-M408V genotype and allele among the 3 different response groups (P>0.05).</p><p><b>CONCLUSION</b>(1) Three single nucleotide polymorphisms (cSNP) P283L, R287G and M408V were found in the hOCT1 gene from 76 Chinese. (2) hOCT1 gene polymorphism is associated with the long-term molecular response of CML patients received IM therapy, indicating that the polymorphisms of hOCT1-283T, 287G may be good predictors for IM response. (3) There is no correlation between the polymorphisms of hOCT1-P283L, R287G, M408V and secondary IM resistance in CML patients.</p>

Identification of a kidney-specific mouse organic cation transporter like-1 (mOCTL1)

Organic ion transporters are expressed in various tissues that transport endogenous and exogenous compounds including their metabolites. There are organic anion transporter (OAT), organic cation transporter (OCT), organic anion transporter like protein (OATLP) and organic cation transporter like (OCTL). Considering the variety of charged organic ionic compounds, the existence of numerous isoforms of organic ion transporters can be assumed. In the present study, we have searched for a new isoform in the expressed sequence tag (EST) database using human organic anion transporter 4 (hOAT4) amino acid sequence as a "query". We found a candidate clone (BC021449) from the mouse kidney cDNA library. This clone was identified as an ortholog of ORCTL3 or OCTL-1. The mOCTL1 cDNA consists of 2016 base pairs encoding 551 amino acid residues with 12 putative transmembrane domains. The deduced amino acid sequence of mOCTL1 showed 35 to 40% identity to those of the other members of the OATs and OCTs. According to the tissue distribution, examined by Northern blot analysis, about a 2.4-kb transcript of mOCTL1 was observed in the kidney. About a 90-kDa band was detected when Western blot analysis in the mouse kidney was done by using antibody against synthesized oligopeptide of mOCTL1. The immunohistochemical result showed that mOCTL1 was stained at the glomerulus (the parietal epithelial cells and podocytes), pars recta of proximal tubule, distal convoluted tubules, connecting tubules and collecting tubules. From these results, we conclude that mOCTL1 may be a candidate for an organic ion transporter isoform in the mouse kidney.

Study of the effect of the low dosage endotoxin damage on the expression of the organic cation transporter (OCT1) mRNA in hepatocytes / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To elucidate the effect of the low dosage endotoxin damage on the expression of the organic cation transporter 1 (OCT1) mRNA in hepatocytes and make an approach to the probable effect of dexamethasone on the expression of the OCT1 mRNA after endotoxin damage.</p><p><b>METHODS</b>(1) The endotoxin damage model was established in rats; (2) The change of the expression of OCT1 mRNA in hepatocytes after endotoxin damage was observed by in situ hybridization method; (3) The change of the ultra structure of hepatocytes after endotoxin damage was observed with the electron microscope; (4) Dexamethasone was injected intraperitoneally before endotoxin damage in order to determine the influence of dexamethasone on the expression of OCT1 mRNA after endotoxin treatment.</p><p><b>RESULTS</b>The expression of OCT1 mRNA decreased until 16 hours (0.5745+/-0.012, P<0.01) after endotoxin treatment and then increased after this time point, which was still lower than the normal control; The expression of OCT1 mRNA in rat hepatocytes increased at each time point after endotoxin damage with dexamethasone treatment. It was highest at 16 hours (0.6327+/-0.007, P<0.01) after endotoxin damage, but it was still lower than that of the normal control.</p><p><b>CONCLUSION</b>Endotoxin could repress the expression of OCT1 mRNA even before the low dosage endotoxin inducing serious damage to the structure of hepatocytes; Dexamethasone could not induce the expression of OCT1 mRNA in normal hepatocytes, but could lighten the repression of endotoxin on the expression of OCT1 mRNA. And then the expression of OCT1 mRNA could increase at some extent after endotoxin damage with dexamethasone treatment.</p>