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Folylpolyglutamate synthase is a major determinant of intracellular methotrexate polyglutamates in patients with rheumatoid arthritis.

ABSTRACT: We investigated major determinants of the intracellular concentrations of methotrexate polyglutamates (MTXPGs) in patients with rheumatoid arthritis (RA). In 271 RA patients on stable oral low dose weekly pulse MTX therapy, the concentrations of MTXPGs in red blood cells (RBCs) were measured by liquid chromatography-electrospray ionization-tandem mass spectrometry. Polymerase chain reaction-restriction fragment length polymorphism analysis was performed to determine the genotypes of solute carrier family 19 member 1 (SLC19A1), folylpolyglutamate synthase (FPGS), and gamma-glutamyl hydrolase (GGH). The mean total MTXPG concentration and the concentrations of individual MTXPGs increased dose-dependently, but reached a plateau at MTX doses >10?mg weekly. The MTXPG3-5/1-2 ratio was lower in patients with adverse events related to MTX than in patients without adverse events. Three polymorphisms of FPGS significantly influenced the MTXPG3-5/1-2 ratio in RBCs, while polymorphisms of SLC19A1 and GGH had no impact. The minor allele frequencies of 2 FPGS genotypes were significantly increased in our patients compared with a Caucasian population. FPGS may have a major role in regulating intracellular polyglutamation of MTX in RA patients receiving low-dose weekly MTX therapy.

SUBMITTER: Yamamoto T

PROVIDER: S-EPMC5067511 | biostudies-literature | 2016 Oct

REPOSITORIES: biostudies-literature

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Folylpolyglutamate synthase is a major determinant of intracellular methotrexate polyglutamates in patients with rheumatoid arthritis.

Yamamoto Tatsuhiro T Shikano Kotaro K Nanki Toshihiro T Kawai Shinichi S

Scientific reports 20161018

We investigated major determinants of the intracellular concentrations of methotrexate polyglutamates (MTXPGs) in patients with rheumatoid arthritis (RA). In 271 RA patients on stable oral low dose weekly pulse MTX therapy, the concentrations of MTXPGs in red blood cells (RBCs) were measured by liquid chromatography-electrospray ionization-tandem mass spectrometry. Polymerase chain reaction-restriction fragment length polymorphism analysis was performed to determine the genotypes of solute carri ...[more]

PMID: 27752107

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Project description:BACKGROUNDInterpatient differences in the accumulation of methotrexate's active polyglutamylated metabolites (MTXPGs) in leukemia cells influence its antileukemic effects.METHODSTo identify genomic and epigenomic and patient variables determining the intracellular accumulation of MTXPGs, we measured intracellular MTXPG levels in acute lymphoblastic leukemia (ALL) cells from 388 newly diagnosed patients after in vivo high-dose methotrexate (HDMTX) (1 g/m2) treatment, defined ALL subtypes, and assessed genomic and epigenomic variants influencing folate pathway genes (mRNA, miRNA, copy number alterations [CNAs], SNPs, single nucleotide variants [SNVs], CpG methylation).RESULTSWe documented greater than 100-fold differences in MTXPG levels, which influenced its antileukemic effects (P = 4 × 10-5). Three ALL subtypes had lower MTXPG levels (T cell ALL [T-ALL] and B cell ALL [B-ALL] with the TCF3-PBX1 or ETV6-RUNX1 fusions), and 2 subtypes had higher MTXPG levels (hyperdiploid and BCR-ABL like). The folate pathway genes SLC19A1, ABCC1, ABCC4, FPGS, and MTHFD1 significantly influenced intracellular MTXPG levels (P = 2.9 × 10-3 to 3.7 × 10-8). A multivariable model including the ALL subtype (P = 1.1 × 10-14), the SLC19A1/(ABCC1 + ABCC4) transporter ratio (P = 3.6 × 10-4), the MTX infusion time (P = 1.5 × 10-3), FPGS mRNA expression (P = 2.1 × 10-3), and MTX systemic clearance (P = 4.4 × 10-2) explained 42% of the variation in MTXPG accumulation (P = 1.1 × 10-38). Model simulations indicated that a longer infusion time (24 h vs. 4 h) was superior in achieving higher intracellular MTXPG levels across all subtypes if ALL.CONCLUSIONSThese findings provide insights into mechanisms underlying interpatient differences in intracellular accumulation of MTXPG in leukemia cells and its antileukemic effectsFUNDINGTHE National Cancer Institute (NCI) and the Institute of General Medical Sciences of the NIH, the Basque Government Programa Posdoctoral de Perfeccionamiento de Personal Investigador doctor, and the American Lebanese Syrian Associated Charities (ALSAC).

Project description:BackgroundMethotrexate (MTX) is the first line treatment for rheumatoid arthritis (RA), but failure of satisfying treatment response occurs in a significant proportion of patients. Here we present a longitudinal multi-omics study aimed at detecting molecular and cellular processes in peripheral blood associated with a successful methotrexate treatment of rheumatoid arthritis.MethodsEighty newly diagnosed patients with RA underwent clinical assessment and donated blood before initiation of MTX, and 3 months into treatment. Flow cytometry was used to describe cell types and presence of activation markers in peripheral blood, the expression of 51 proteins was measured in serum or plasma, and RNA sequencing was performed in peripheral blood mononuclear cells (PBMC). Response to treatment after 3 months was determined using the EULAR response criteria. We assessed the changes in biological phenotypes during treatment, and whether these changes differed between responders and non-responders with regression analysis. By using measurements from baseline, we also tried to find biomarkers of future MTX response or, alternatively, to predict MTX response.ResultsAmong the MTX responders, (Good or Moderate according to EULAR treatment response classification, n = 60, 75%), we observed changes in 29 partly overlapping cell types proportions, levels of 13 proteins and expression of 38 genes during treatment. These changes were in most cases suppressions that were stronger among responders compared to non-responders. Within responders to treatment, we observed a suppression of FOXP3 gene expression, reduction of immunoglobulin gene expression and suppression of genes involved in cell proliferation. The proportion of many HLA-DR expressing T-cell populations were suppressed in all patients irrespective of clinical response, and the proportion of many IL21R+ T-cells were reduced exclusively in non-responders. Using only the baseline measurements we could not detect any biomarkers or prediction models that could predict response to MTX.ConclusionWe conclude that a deep molecular and cellular phenotyping of peripheral blood cells in RA patients treated with methotrexate can reveal previously not recognized differences between responders and non-responders during 3 months of treatment with MTX. This may contribute to the understanding of MTX mode of action and explain non-responsiveness to MTX therapy.

Project description:ObjectivePatients with rheumatoid arthritis (RA) in whom remission is achieved following combination therapy with methotrexate plus etanercept face an ongoing medication burden. This study was undertaken to investigate whether sustained remission achieved on combination therapy can be maintained with either methotrexate or etanercept monotherapy, as assessed following discontinuation of one or the other medication from the combination.MethodsOf the 371 adult patients with RA who received combination therapy with methotrexate plus etanercept, remission (defined as a Simplified Disease Activity Index [SDAI] score of ≤3.3) was sustained in 253 patients through a 24-week open-label period. These 253 patients then entered a 48-week, double-blind period and were randomized to receive either 1) methotrexate monotherapy (n = 101), 2) etanercept monotherapy (n = 101), or 3) methotrexate plus etanercept combination therapy (n = 51). Patients who subsequently experienced disease-worsening received rescue therapy with the combination regimen at the same dosages as used in the initial run-in period. The primary end point was the proportion of patients in whom SDAI-defined remission was maintained without disease-worsening at week 48 in the etanercept monotherapy group as compared to the methotrexate monotherapy group. Secondary end points included time to disease-worsening, and the proportion of patients in whom SDAI-defined remission was recaptured after initiation of rescue therapy.ResultsBaseline demographic and clinical characteristics of the RA patients were similar across the treatment groups. At week 48, SDAI-defined remission was maintained in significantly more patients in the etanercept monotherapy group than in the methotrexate monotherapy group (49.5% versus 28.7%; P = 0.004). Moreover, as a secondary end point, sustained SDAI-defined remission was achieved in significantly more patients who received combination therapy than in those who received methotrexate monotherapy (52.9% versus 28.7%; P = 0.006). Time to disease-worsening was shorter in those who received methotrexate monotherapy than in those who received etanercept monotherapy or those who received combination therapy (each P < 0.001 versus methotrexate monotherapy). Among the patients who received rescue therapy, SDAI-defined remission was recaptured in 70-80% in each treatment group. No new safety signals were reported.ConclusionThe efficacy of etanercept monotherapy was superior to that of methotrexate monotherapy and similar to that of combination therapy in maintaining remission in patients with RA. SDAI-defined remission was recaptured in most of the patients who were given rescue therapy. These data could inform decision-making when withdrawal of therapy is being considered to reduce treatment burden in patients with well-controlled RA.

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Folylpolyglutamate synthase is a major determinant of intracellular methotrexate polyglutamates in patients with rheumatoid arthritis.

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Folylpolyglutamate synthase is a major determinant of intracellular methotrexate polyglutamates in patients with rheumatoid arthritis.

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