MiR-pharmacogenetics of methotrexate in childhood B-cell acute lymphoblastic leukemia

The placental blood perfusion and LINC00473-mediated promotion of trophoblast apoptosis in fetal growth restriction

This study aimed to investigate placental microblood flow perfusion in fetal growth restriction (FGR) both pre- and post-delivery, and explore the influence of LINC00473 and its downstream targets on FGR progression in trophoblast cells. Placental vascular distribution, placental vascular index (VIMV), CD34 expression, and histological changes were compared between control and FGR groups. FGR-related differentially expressed genes (DEGs) were analyzed and validated by quantitative real-time polymerase chain reaction (qPCR) and immunohistochemistry (IHC) in placentae. In vitro experiments examined the regulatory relationships among LINC00473, miR-5189-5p, and StAR, followed by investigations into their impacts on cell proliferation and apoptosis. FGR placentae exhibited irregular shapes, uneven parenchymal echo, stromal dysplasia, ischemic infarction, and variable degrees of thickening in some cases. FGR samples showed less prominent mother vessel lakes, significantly lower VIMV, and decreased CD34 expression. Hematoxylin & eosin (H&E) staining revealed placental fibrosis, fibrin adhesion, infarction, and interstitial dysplasia in FGR. LINC00473, miR-5189-5p, and StAR were identified as DEG, with qPCR demonstrating a significant increase in LINC00473 and a decrease in miR-5189-5p in FGR, while both qPCR and IHC indicated a significant increase in StAR expression. LINC00473 served as an endogenous sponge against miR-5189-5p in human HTR-8/SV neo cells, and StAR expression was regulated by both LINC00473 and miR-5189-5p. Dysregulation of these genes affected cell proliferation and apoptosis. Pathological changes in the placenta are significant contributors to FGR, with placental microblood flow potentially serving as an indicator for monitoring its progression. LINC00473 and its downstream targets may modulate trophoblasts proliferation and apoptosis, thus influencing the onset of FGR, suggesting novel avenues for diagnosis and treatment.

Association of microRNA Polymorphisms with Toxicities Induced by Methotrexate in Children with Acute Lymphoblastic Leukemia

Methotrexate (MTX), a structurally related substance to folic acid, is an important chemotherapeutic agent used for decades in the treatment of pediatric acute lymphoblastic leukemia (ALL) and other types of cancer as non-Hodgkin lymphomas and osteosarcomas. Despite the successful outcomes observed, the primary drawback is the variability in the pharmacokinetics and pharmacodynamics between patients. The main adverse events related to its use are nephrotoxicity, mucositis, and myelosuppression, especially when used in high doses. The potential adverse reactions and toxicities associated with MTX are a cause for concern and may lead to dose reduction or treatment interruption. Genetic variants in MTX transport genes have been linked to toxicity. Pharmacogenetic studies conducted in the past focused on single nucleotide polymorphisms (SNPs) in the coding and 5'-regulatory regions of genes. Recent studies have demonstrated a significant role of microRNAs (miRNAs) in the transport and metabolism of drugs and in the regulation of target genes. In the last few years, the number of annotated miRNAs has continually risen, in addition to the studies of miRNA polymorphisms and MTX toxicity. Therefore, the objective of the present study is to investigate the role of miRNA variants related to MTX adverse effects.

Exosomal miR-200c and miR-141 as cerebrospinal fluid biopsy biomarkers for the response to chemotherapy in primary central nervous system lymphoma

BACKGROUND

To improve early diagnosis and chemotherapy efficacy monitoring in primary central nervous system lymphoma (PCNSL), cerebrospinal fluid (CSF) exosomal microRNA (miRNA) studies were performed.

METHOD

Small RNA sequencing was performed to identify candidate exosomal miRNAs as CSF biopsy biomarkers from two patients with de novo PCNSL and two patients in remission after chemotherapy. miR-200c and miR-141 expression in CSF exosomes was further validated using relative quantitative real-time polymerase chain reaction in patients with PCNSL (n = 20), patients with other neurological diseases (n = 10), and normal subjects (n = 10). Receiver operating characteristic (ROC) curve analyses of miR-200c and miR-141 in the diagnosis and prediction of chemotherapy efficacy in PCNSL were performed in patients treated with methotrexate. Additionally, bioinformatics tools were utilized to predict the potential targets of miR-200c and miR-141.

RESULTS

Exosomal miR-200c and miR-141 levels in CSF from patients with PCNSL were significantly lower than those in control subjects. Importantly, miR-200c and miR-141 were upregulated in patients with PCNSL after chemotherapy (P = 0.002). There was a significant correlation between the levels of miR-141 and IL-10 in CSF (P = 0.04). The combination of miR-200c and miR-141 yielded an area under the ROC curve of 0.761 for distinguishing PCNSL with sensitivity and specificity of 60.0% and 96.7%, respectively. The potential target genes of miR-200c and miR-141 in PCNSL included ATP1B3, DYNC1H1, MATR3, NUCKS1, ZNF638, NUDT4, RCN2, GNPDA1, ZBTB38, and DOLK.

CONCLUSION

Collectively, miR-200c and miR-141 are likely to be upregulated in CSF exosomes after chemotherapy in patients with PCNSL, highlighting their potential as reliable liquid biopsy biomarkers for PCNSL diagnosis and chemotherapy efficacy monitoring.

Impact of microRNA polymorphisms on high-dose methotrexate-related hematological toxicities in pediatric acute lymphoblastic leukemia

Objectives

It is well known that transporter and enzyme genes could be regulated by microRNA (miRNA) at the post-transcriptional level, and single-nucleotide polymorphisms (SNPs) in miRNA, which are involved in the miRNA production and structure, may impact the miRNA expression level and then influence drug transport and metabolism. In this study, we aim to evaluate the association between miRNA polymorphisms and high-dose methotrexate (HD-MTX) hematological toxicities in Chinese pediatric patients with acute lymphoblastic leukemia (ALL).

Method

A total of 181 children with ALL were administered with 654 evaluable cycles of HD-MTX. Their hematological toxicities were evaluated according to the National Cancer Institute Common Terminology Criteria for Adverse Events v5. The association between 15 candidate SNPs of miRNA and hematological toxicities (leukopenia, anemia, and thrombocytopenia) was analyzed using Fisher's exact test. Further multiple backward logistic regression analysis was used to explore the independent risk factors for grade 3/4 hematological toxicities.

Result

Rs2114358 G>A in pre-hsa-miR-1206 was related to HD-MTX-related grade 3/4 leukopenia after multiple logistic regression [GA + AA vs. GG: odds ratio (OR): 2.308, 95% CI: 1.219-4.372, P = 0.010], and rs56103835 T > C in pre-hsa-mir-323b was associated with HD-MTX-related grade 3/4 anemia (TT + TC vs. CC: OR: 0.360, 95% CI: 0.239-0.541, P = 0.000); none of the SNPs were significantly associated with grade 3/4 thrombocytopenia. Bioinformatics tools predicted that rs2114358 G>A and rs56103835 T>C would impact the secondary structure of pre-miR-1206 and pre-miR-323b, respectively, and then probably influence the expression level of mature miRNAs and their target genes.

Conclusion

Rs2114358 G>A and rs56103835 T>C polymorphism may potentially influence HD-MTX-related hematological toxicities, which may serve as candidate clinical biomarkers to predict grade 3/4 hematological toxicities in pediatric patients with ALL.

MiRNAs in Hematopoiesis and Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common kind of pediatric cancer. Although the cure rates in ALL have significantly increased in developed countries, still 15–20% of patients relapse, with even higher rates in developing countries. The role of non-coding RNA genes as microRNAs (miRNAs) has gained interest from researchers in regard to improving our knowledge of the molecular mechanisms underlying ALL development, as well as identifying biomarkers with clinical relevance. Despite the wide heterogeneity reveled in miRNA studies in ALL, consistent findings give us confidence that miRNAs could be useful to discriminate between leukemia linages, immunophenotypes, molecular groups, high-risk-for-relapse groups, and poor/good responders to chemotherapy. For instance, miR-125b has been associated with prognosis and chemoresistance in ALL, miR-21 has an oncogenic role in lymphoid malignancies, and the miR-181 family can act either as a oncomiR or tumor suppressor in several hematological malignancies. However, few of these studies have explored the molecular interplay between miRNAs and their targeted genes. This review aims to state the different ways in which miRNAs could be involved in ALL and their clinical implications.

Associations Between microRNA-related Genetic Polymorphisms and Clinical Response to Methotrexate in Chinese Rheumatoid Arthritis Patients

BACKGROUND

Emerging evidence indicates that microRNA (miRNA)-related genetic polymorphisms are strongly involved in the post-transcriptional regulation of the expression of pharmacokinetics and pharmacodynamics- related genes, therefore contributing to the genetic variability of drug response.

OBJECTIVE

To investigate the associations of miRNA-related genetic polymorphisms, including miRNA-5189 rs562929801, miRNA-595 rs4909237, SLCO1A2 rs4149009 and MTHFR rs3737966, and clinical response to methotrexate in Chinese rheumatoid arthritis patients.

METHODS

One hundred patients treated with MTX for approximately 3 months were prospectively followed up to evaluate the clinical response according to European League Against Rheumatism (EULAR) good and moderate response, disease activity score in 28 joint counts - erythrocyte sedimentation rate (DAS28-ESR) low disease activity (LDA) and remission (REM), change in DAS28-ESR (ΔDAS28-ESR) and ΔDAS28-ESR > 0.6. Genetic polymorphisms were genotyped utilizing the HI-SNP technology.

RESULTS

Of the 100 patients with a mean age of 52.23 ± 12.71 years, 81 patients were female (81.00%). After adjusting potential confounders, the major allele of miRNA-5189 rs562929801 was found to be significantly associated with EULAR response (A/A + A/G versus G/G, RR = 0.81, 95% CI = 0.67-0.99, P = 0.04) and ΔDAS28-ESR > 0.6 under dominant model (A/A + A/G versus G/G, RR = 0.83, 95% CI = 0.71-0.98, P = 0.03). However, nonsignificant evidence was detected for the remaining three miRNA-related genetic polymorphisms in neither univariable analysis nor multivariable analysis.

CONCLUSION

Our results indicated that miRNA-5189 rs562929801 was significantly associated with clinical response to MTX, and this association warrants further replication studies with larger sample sizes.

Functional Screen for microRNAs Suppressing Anchorage-Independent Growth in Human Cervical Cancer Cells

The progression of anchorage-dependent epithelial cells to anchorage-independent growth represents a critical hallmark of malignant transformation. Using an in vitro model of human papillomavirus (HPV)-induced transformation, we previously showed that acquisition of anchorage-independent growth is associated with marked (epi)genetic changes, including altered expression of microRNAs. However, the laborious nature of the conventional growth method in soft agar to measure this phenotype hampers a high-throughput analysis. We developed alternative functional screening methods using 96- and 384-well ultra-low attachment plates to systematically investigate microRNAs regulating anchorage-independent growth. SiHa cervical cancer cells were transfected with a microRNA mimic library (n = 2019) and evaluated for cell viability. We identified 84 microRNAs that consistently suppressed growth in three independent experiments. Further validation in three cell lines and comparison of growth in adherent and ultra-low attachment plates yielded 40 microRNAs that specifically reduced anchorage-independent growth. In conclusion, ultra-low attachment plates are a promising alternative for soft-agar assays to study anchorage-independent growth and are suitable for high-throughput functional screening. Anchorage independence suppressing microRNAs identified through our screen were successfully validated in three cell lines. These microRNAs may provide specific biomarkers for detecting and treating HPV-induced precancerous lesions progressing to invasive cancer, the most critical stage during cervical cancer development.

Population pharmacokinetics of methotrexate in pediatric patients with acute lymphoblastic leukemia and malignant lymphoma

1. This study aimed to identify physiological and pharmacogenomic covariates and develop a population pharmacokinetic model of high-dose methotrexate (HD-MTX) in Chinese pediatric patients with acute lymphoblastic leukemia (ALL) and malignant lymphoma.2. A total 731 MTX courses and 1658 MTX plasm concentration from 205 pediatric patients with ALL and malignant lymphoma were analyzing using a nonlinear mixed-effects model technique. 47 SNPs in 16 MTX-related gene were genotyped and screened as covariates. A PPK model was established to determine the influence of covariates such as body surface area (BSA), age, laboratory test value, and SNPs on the pharmacokinetic process of HD-MTX.3. Two-compartmental model with allometric scaling using BSA could nicely characterize the in vivo behavior of HD-MTX. After accounting for body size, rs17004785 and rs4148416 were the covariates that influence MTX clearance (CL). The PPK model obtained was: CL =9.33 * (BSA/1.73) ^0.75 * e^{0.13*rs17004785} * e^{0.39*rs4148416} * e^ηCL, Vc =24.98 * (BSA/1.73) * e^ηvc, Q = 0.18 * (BSA/1.73) ^0.75 * e^ηQ and Vp =4.70 * (BSA/1.73) * e^ηvp.4. The established model combined with Bayesian approach could estimate individual pharmacokinetic parameters and optimize personalized HD-MTX therapy for pediatric patients with ALL and malignant lymphoma.

Dioscin ameliorates methotrexate-induced liver and kidney damages via adjusting miRNA-145-5p-mediated oxidative stress

Dioscin, one natural product, has various pharmacological actions. However, its effects on methotrexate (MTX)-induced hepatorenal damages still remain unknown. In the present study, the data manifested that dioscin restored the viabilities of L-02 and NRK-52E cells, reduced ALT, AST, Cr, BUN levels, and ameliorated histopathological changes of liver and kidney. Besides, dioscin decreased ROS levels in cells, and adjusted SOD, MDA, GSH and GSH-Px levels in rats. Dioscin reduced the expression levels of miR-145-5p which directly targeted Sirt5, and then regulated the expression levels of SOD1, Nrf2, Gst, Keap1, HO-1, GCLC and NQO1. MiR-145-5p mimic in cells deteriorated ROS levels and decreased Sirt5 expression to accentuate oxidative stress by regulating the expression levels of SOD1, Nrf2, Keap1, which were all reversed by dioscin. Moreover, MTX-induced hepatorenal damage were worsened in mice by Sirt5 siRNA or miR-145-5p agomir, which were also alleviated by dioscin. Dioscin relieved MTX-induced hepatorenal damages through regulating miR-145-5p-medicated oxidative stress, which should be considered as one effective drug to treat the disorder in future.

Implementation of Pharmacogenetics to Individualize Treatment Regimens for Children with Acute Lymphoblastic Leukemia

Despite major advances in the management and high cure rates of childhood acute lymphoblastic leukemia (ALL), patients still suffer from many drug-induced toxicities, sometimes necessitating dose reduction, or halting of cytotoxic drugs with a secondary risk of disease relapse. In addition, investigators have noted significant inter-individual variability in drug toxicities and disease outcomes, hence the role of pharmacogenetics (PGx) in elucidating genetic polymorphisms in candidate genes for the optimization of disease management. In this review, we present the PGx data in association with main toxicities seen in children treated for ALL in addition to efficacy, with a focus on the most plausible germline PGx variants. We then follow with a summary of the highest evidence drug-gene annotations with suggestions to move forward in implementing preemptive PGx for the individualization of treatment regimens for children with ALL.

MicroRNA signature associated with treatment response in myasthenia gravis: A further step towards precision medicine

Myasthenia gravis (MG) is an autoimmune disorder affecting neuromuscular transmission currently treated with chronic immunosuppression. Inter-subject variation in treatment response and side effects highlight the need for personalized therapies by identification of biomarkers predictive of drug efficacy in individual patients, still lacking in MG. MicroRNAs (miRNAs) play a key role in immune response and drug metabolism modulation. This study, part of an Italian-Israeli collaborative project, aimed to identify specific miRNAs as biomarkers associated with immunosuppressive treatment response in MG patients. Whole miRNome sequencing, followed by miRNA validation by real-time PCR, was performed in peripheral blood from Italian MG patients (n = 40) classified as responder and non-responder to immunosuppressive therapies. MiRNA sequencing identified 41 miRNAs differentially expressed in non-responder compared to responder Italian MG patients. Validation phase pointed out three miRNAs, miR-323b-3p, -409-3p, and -485-3p, clustered on chromosome 14q32.31, the levels of which were significantly decreased in non-responder versus responder patients, whereas miR-181d-5p and -340-3p showed an opposite trend. ROC curve analysis showed sensitivity and specificity performance results indicative of miR-323b-3p, -409-3p, and -485-3p predictive value for responsiveness to immunosuppressive drugs in MG. Validated miRNAs were further analyzed in blood from responder and non-responder MG patients of the Israeli population (n = 33), confirming a role for miR-323b-3p, -409-3p, -485-3p, -181d-5p and -340-3p as biomarkers of drug efficacy. Gene Ontology enrichment analysis, mRNA target prediction, and in silico modeling for function of the identified miRNAs disclosed functional involvement of the five miRNAs, and their putative target genes, in both immune (i.e. neurotrophin TRK and Fc-epsilon receptor signaling pathways) and drug metabolism processes. Our overall findings thus revealed a blood "miR-323b-3p, -409-3p, -485-3p, -181d-5p, and -340-3p" signature associated with drug responsiveness in MG patients. Its identification sets the basis for precision medicine approaches based on "pharmacomiRs" as biomarkers of drug responsiveness in MG, promising to improve therapeutic success in a cost/effective manner.

Methotrexate Disposition in Pediatric Patients with Acute Lymphoblastic Leukemia: What Have We Learnt From the Genetic Variants of Drug Transporters

Background:

Methotrexate (MTX) is one of the leading chemotherapeutic agents with the bestdemonstrated efficacies against childhood acute lymphoblastic leukemia (ALL). Due to the narrow therapeutic range, significant inter- and intra-patient variabilities of MTX, non-effectiveness and/or toxicity occur abruptly to cause chemotherapeutic interruption or discontinuation. The relationship between clinical outcome and the systemic concentration of MTX has been well established, making the monitoring of plasma MTX levels critical in the treatment of ALL. Besides metabolizing enzymes, multiple transporters are also involved in determining the intracellular drug levels. In this mini-review, we focused on the genetic polymorphisms of MTX-disposition related transporters and the potential association between the discussed genetic variants and MTX pharmacokinetics, efficacy, and toxicity in the context of MTX treatment.

Methods:

We searched PubMed for citations published in English using the terms “methotrexate”, “transporter”, “acute lymphoblastic leukemia”, “polymorphisms”, and “therapeutic drug monitoring”. The retrieval papers were critically reviewed and summarized according to the aims of this mini-review.

Results:

Solute carrier (SLC) transporters (SLC19A1, SLCO1A2, SLCO1B1, and SLC22A8) and ATP-binding cassette (ABC) transporters (ABCB1, ABCC2, ABCC3, ABCC4, ABCC5, and ABCG2) mediate MTX disposition. Of note, the influences of polymorphisms of SLC19A1, SLCO1B1 and ABCB1 genes on the clinical outcome of MTX have been extensively studied.

Conclusion:

Overall, the data critically reviewed in this mini-review article confirmed that polymorphisms in the genes encoding SLC and ABC transporters confer higher sensitivity to altered plasma levels, MTX-induced toxicity, and therapeutic response in pediatric patients with ALL. Pre-emptive determination may be helpful in individualizing treatment.

Clinical Implications of Methotrexate Pharmacogenetics in Childhood Acute Lymphoblastic Leukaemia

Background:

In the past two decades, a great body of research has been published regarding the effects of genetic polymorphisms on methotrexate (MTX)-induced toxicity and efficacy. Of particular interest is the role of this compound in childhood acute lymphoblastic leukaemia (ALL), where it is a pivotal drug in the different treatment protocols, both at low and high doses. MTX acts on a variety of target enzymes in the folates cycle, as well as being transported out and into of the cell by several transmembrane proteins.

Methods:

We undertook a structured search of bibliographic databases for peer-reviewed research literature using a focused review question.

Results:

This review has intended to summarize the current knowledge concerning the clinical impact of polymorphisms in enzymes and transporters involved in MTX disposition and mechanism of action on paediatric patients with ALL.

Conclusion:

In this work, we describe why, in spite of the significant research efforts, pharmacogenetics findings in this setting have not yet found their way into routine clinical practice.

Efficacy and association analysis of high-dose methotrexate in the treatment of children with acute lymphoblastic leukemia

Effect of high-dose methotrexate (MTX) on children with acute lymphoblastic leukemia (ALL) with different subtypes and disease courses was investigated. A retrospective analysis of 207 children with ALL who were admitted to the People's Hospital of Pingyi County from March 2014 to June 2017 was carried out. According to the subtype of the disease, the children were divided into two groups. B-lineage group: ALL occurred in B-lineage lymphocytes (n=128); T-lineage group: ALL occurred in T-lineage lymphocytes (n=79). According to the disease course, the children were divided into three groups. High-risk group: disease course >15 days (n=67); moderate-risk group: disease course >8 and <15 days (n=58); low-risk group: disease course <8 days (n=82). The plasma concentration, calcium formyltetrahydrofolate (CF) rescue times and adverse reactions were compared at 12 h (T1), 48 h (T2), and 72 h (T3) after MTX infusion. The plasma concentration in B-lineage group was significantly higher than that in the T-lineage group at T2 and T3 (P<0.05). The incidence of adverse reactions in children with ALL in the B-lineage group was significantly higher than that in the T-lineage group (P<0.05). The CF rescue times in high-risk group were more than that in moderate- and low-risk groups (P<0.05). The incidence of adverse reactions in the high-risk group was significantly higher than that in the moderate- and low-risk groups (P<0.05), and in the moderate-risk group was significantly higher than that in the low-risk group (P<0.05). Compared with T-lineage ALL children, high-dose MTX causes more toxic injury to B-lineage ALL children. During clinical application of MTX in the treatment of ALL, close attention should be paid to the changes of the vital signs of patients, and timely CF rescue should be performed.

Variants in vincristine pharmacodynamic genes involved in neurotoxicity at induction phase in the therapy of pediatric acute lymphoblastic leukemia

Vincristine is an important drug of acute lymphoblastic leukemia (ALL) treatment protocols that can cause neurotoxicity. Patients treated with LAL/SHOP protocols often suffer from vincristine-related neurotoxicity in early phases of treatment. A genetic variant in CEP72, a gene involved in vincristine pharmacodynamics, was recently associated with neurotoxicity after prolonged vincristine treatment. This association was not replicated in our Spanish population during induction phase. To test the possibility that other variants in genes involved in vincristine pharmacodynamics were associated with vincristine neuropathy in early phases of the treatment, we evaluated the correlation with toxicity of 24 polymorphisms in 9 key genes in a large cohort of 152 Spanish children with B-ALL homogeneously treated. Results showed no association between any genetic variant in the TUBB1, TUBB2A, TUBB2B, TUBB3, TUBB4, MAPT, MIR146a, MIR202, and MIR411 genes and vincristine-related neurotoxicity. These results are in line with the hypothesis that there are different mechanisms causing pheripheral neurotoxicity after prolonged and short-term vincristine treatments.

MiRNA Dysregulation in Childhood Hematological Cancer

For decades, cancer biology focused largely on the protein-encoding genes that have clear roles in tumor development or progression: cell-cycle control, apoptotic evasion, genome instability, drug resistance, or signaling pathways that stimulate growth, angiogenesis, or metastasis. MicroRNAs (miRNAs), however, represent one of the more abundant classes of cell modulators in multicellular organisms and largely contribute to regulating gene expression. Many of the ~2500 miRNAs discovered to date in humans regulate vital biological processes, and their aberrant expression results in pathological and malignant outcomes. In this review, we highlight what has been learned about the roles of miRNAs in some of the most common human pediatric leukemias and lymphomas, along with their value as diagnostic/prognostic factors.

Epigenetics and MicroRNAs in Pharmacogenetics

Germline pharmacogenetics has so far mainly studied common variants in "pharmacogenes," i.e., genes encoding drug metabolizing enzymes and transporters (DMET genes), certain auxiliary and regulatory genes, and drug target genes. Despite remarkable progress in understanding genetically determined differences in pharmacokinetics and pharmacodynamics of drugs, currently known common variants even in important pharmacogenes explain genetic variability only partially. This suggests "missing heritability" that may in part be due to rare variants in the classical pharmacogenes, but current evidence suggests that largely unexplored resources with potential for pharmacogenetics exist, both within already known pharmacogenes and in entirely new areas. In particular, recent studies suggest that epigenetic processes and noncoding RNAs, including mostly microRNAs (miRNAs), represent important and largely unexplored layers of DMET gene regulation that may fill some of the gaps in understanding interindividual variability and lead to new biomarkers. In this chapter we summarize recent advances in the understanding of genetic variability in epigenetic and miRNA-mediated processes with focus on their significance for DMET regulation and pharmacokinetic or pharmacological endpoints.

Pharmacoepigenetics in childhood acute lymphoblastic leukemia: involvement of miRNA polymorphisms in hepatotoxicity

AIM

Hepatotoxicity is one of the most common drug-related toxicities during the treatment of childhood acute lymphoblastic leukemia (ALL). Many genes involved in liver-specific signaling pathways are tightly controlled by miRNAs, and miRNA function could be modulated by SNPs. As a consequence, we hypothesized that variants in miRNAs could be associated with drug-induced hepatotoxicity.

METHODS

We analyzed 213 SNPs in 206 miRNAs in a cohort of 179 children with ALL homogeneously treated.

RESULTS

rs2648841 in miR-1208 was the most significant SNP during consolidation phase after false discovery rate correction, probably through an effect on its target genes DHFR, MTR and MTHFR.

CONCLUSION

These results point out the possible involvement of SNPs in miRNAs in toxicity to chemotherapy in children with ALL.

Haplotype-based association of two SNPs in miR-323b with unexplained recurrent spontaneous abortion in a Chinese Han population

Single nucleotide polymorphisms (SNPs) in miRNAs are associated with the risk to development of certain human diseases and affect the regulatory capacity of miRNAs. However, the relationship between miRNAs polymorphisms and recurrent pregnancy loss (RPL) is still largely unknown. Our study found that one SNP rs56103835 T>C in miR-323b coding region was associated with the increase risk of human unexplained RPL (URPL), but no differences were found in another SNP rs75330474 C>T. However, in two-locus haplotype analysis, T-C haplotype was associated with an increased risk of URPL. The level of mature miR-323b was obviously up-regulated in cells transfected with T-C haplotype. T-C haplotype inhibited HTR-8/SVneo cells proliferation and migration and promoted cells apoptosis. Further experiments identified that paired-box 8 (Pax8) was a functionally relevant target of miR-323b, and its expression was reversely regulated by miR-323b. Besides, the expressions of Pax8 in villous chorionic tissues from URPL patients were lower than controls, contrary to the high expression of miR-323. More importantly, dual-luciferase assay indicated T-C haplotype, increasing miR-323b expression, could down-regulated Pax8 expression. Collectively, our data suggest that T-C haplotype in pre-miR-323b may aggravate the risk of developing URPL and influence the level of mature miR-323b and its target gene Pax8.

MiR-595 Suppresses the Cellular Uptake and Cytotoxic Effects of Methotrexate by Targeting SLC19A1 in CEM/C1 Cells

The human solute carrier family 19 member 1 (SLC19A1) is the gene coding for reduced folate carrier 1 (RFC1). In our previous work, we showed that the miR-595-related polymorphism, rs1051296 G>T, which was located in the 3'-untranslated region (3'-UTR) of SLC19A1, was associated with high methotrexate (MTX) plasma concentrations in patients with paediatric acute lymphoblastic leukaemia (ALL). This study aimed to investigate the role of miR-595 in the regulation of SLC19A1 expression and its effects on the cellular uptake and cytotoxicity of MTX in ALL CEM/C1 cells. Luciferase reporter assay was performed to validate SLC19A1 as a miR-595 target. RFC1 protein expression was determined via Western blotting. Intracellular MTX concentrations were measured by enzyme-linked immunosorbent assay (ELISA). Cell viability and apoptosis were assessed using Cell Counting Kit-8 (CCK-8) assay and flow cytometer, respectively. Compared to the negative control, miR-595 mimics induced a significant decrease in the relative luciferase activity by binding to the 3'-UTR of SLC19A1 harbouring the rs1051296 T allele (p < 0.01). Treatment of CEM/C1 cells with miR-595 mimics substantially reduced RFC1 protein expression, intracellular MTX levels, MTX-induced cytotoxicity and apoptosis rates compared to those of negative control. However, opposite results were observed in cells transfected with a miR-595 inhibitor. These findings suggested that miR-595 acts as a phenotypic regulator of MTX sensitivity in CEM/C1 cells by targeting SLC19A1. This study helped us to understand the mechanisms underlying the variable MTX responses observed in patients with ALL.

Role of miRNAs in treatment response and toxicity of childhood acute lymphoblastic leukemia

Childhood acute lymphoblastic leukemia survival rates have increased remarkably during last decades due, in part, to intensive treatment protocols. However, therapy resistance and toxicity are still two important barriers to survival. In this context, pharmacoepigenetics arises as a tool to identify new predictive markers, required to guide clinicians on risk stratification and dose individualization. The present study reviews current evidence about miRNA implication on childhood acute lymphoblastic leukemia therapy resistance and toxicity. A total of 12 studies analyzing differential miRNA expression in relation to drug resistance and six studies exploring the association between miRNAs-related SNPs and drug-induced toxicities were identified. We pointed out to miR-125b together with miR-99a and/or miR-100 overexpression as markers of vincristine resistance and rs2114358 in mir-1206 as mucositis marker as the most promising results.

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.

Mir-pharmacogenetics of Vincristine and peripheral neurotoxicity in childhood B-cell acute lymphoblastic leukemia

Vincristine (VCR), an important component of childhood acute lymphoblastic leukemia (ALL) therapy, can cause sensory and motor neurotoxicity. This neurotoxicity could lead to dose reduction or treatment discontinuation, which could in turn reduce survival. In this line, several studies associated peripheral neurotoxicity and polymorphisms in genes involved in pharmacokinetics (PK) and pharmacodynamics (PD) of VCR. Nowadays, it is well known that these genes are regulated by microRNAs (miRNAs) and SNPs in miRNAs could modify their levels or function. Therefore, the aim of this study was to determine whether SNPs in miRNAs could be associated with VCR-induced neurotoxicity. To achieve this aim, we analyzed all the SNPs in miRNAs (minor allele frequency (MAF) ≥ 0.01) which could regulate VCR-related genes in a large cohort of Spanish children with B-cell precursor ALL (B-ALL) homogeneously treated with LAL/SHOP protocols. We identified the A allele of rs12402181 in the seed region of miR-3117-3p, that could affect the binding with ABCC1 and RALBP1 gene, and C allele of rs7896283 in pre-mature sequence of miR-4481, which could be involved in peripheral nerve regeneration, significantly associated with VCR-induced neurotoxicity. These findings point out the possible involvement of two SNPs in miRNA associated with VCR-related neurotoxicity.

Review of pharmacogenetics studies of L-asparaginase hypersensitivity in acute lymphoblastic leukemia points to variants in the GRIA1 gene

Acute lymphoblastic leukemia (ALL) is a major pediatric cancer in developed countries. Although treatment outcome has improved owing to advances in chemotherapy, there is still a group of patients who experience severe adverse events. L-Asparaginase is an effective antineoplastic agent used in chemotherapy of ALL. Despite its indisputable indication, hypersensitivity reactions are common. In those cases, discontinuation of treatment is usually needed and anti-asparaginase antibody production may also attenuate asparaginase activity, compromising its antileukemic effect. Till now, six pharmacogenetic studies have been performed in order to elucidate possible genetic predisposition for inter-individual differences in asparaginase hypersensitivity. In this review we have summarized the results of those studies which describe the involvement of four different genes, being polymorphisms in the glutamate receptor, ionotropic, AMPA 1 (GRIA1) the most frequently associated with asparaginase hypersensitivity. We also point to new approaches focusing on epigenetics that could be interesting for consideration in the near future.

Association between SLC19A1 Gene Polymorphism and High Dose Methotrexate Toxicity in Childhood Acute Lymphoblastic Leukaemia and Non Hodgkin Malignant Lymphoma: Introducing a Haplotype based Approach

Background

We investigated the clinical relevance of SLC 19A1 genetic variability for high dose methotrexate (HD-MTX) related toxicities in children and adolescents with acute lymphoblastic leukaemia (ALL) and non Hodgkin malignant lymphoma (NHML).

Patients and methods

Eighty-eight children and adolescents with ALL/NHML were investigated for the influence of SLC 19A1 single nucleotide polymorphisms (SNPs) and haplotypes on HD-MTX induced toxicities.

Results

Patients with rs2838958 TT genotype had higher probability for mucositis development as compared to carriers of at least one rs2838958 C allele (OR 0.226 (0.071–0.725), p < 0.009). Haplotype TGTTCCG (H4) statistically significantly reduced the risk for the occurrence of adverse events during treatment with HD-MTX (OR 0.143 (0.023–0.852), p = 0.030).

Conclusions

SLC 19A1 SNP and haplotype analysis could provide additional information in a personalized HD-MTX therapy for children with ALL/NHML in order to achieve better treatment outcome. However further studies are needed to validate the results.

Pharmacogenomics in pediatric acute lymphoblastic leukemia: promises and limitations

Despite the significant advances achieved in pediatric acute lymphocytic leukemia (ALL) treatment, adverse side effects of drugs remain a challenging issue. Numerous ALL pharmacogenomic studies have been conducted to elucidate the predisposing genetic factors for their development. Plausible pharmacogenomic data are available for the osteonecrosis associated with glucocorticoids, the neurotoxicity associated with vincristine and the cardiotoxicity related to anthracyclines. However, these data have not been fully translated into the clinic due to several limitations, most importantly the lack of reliable evidence. The most robust pharmacogenomics data are those for thiopurines and methotrexate use, with evidence-based preemptive testing recommendations for the former. Pharmacogenomics has a significant potential utility in pediatric ALL treatment regimens. In this review, gaps and limitations in this field are emphasized, which may provide a useful guide for future research design.

MTHFR polymorphisms in childhood acute lymphoblastic leukemia: influence on methotrexate therapy

Methotrexate (MTX) is an important component in the therapy used to treat childhood acute lymphoblastic leukemia (ALL). Methylenetetrahydrofolate reductase (MTHFR) is a key enzyme for MTX pharmacokinetics. Two single-nucleotide polymorphisms in MTHFR gene, C677T and A1298C, affecting MTHFR activity, have been widely studied as potential markers of MTX toxicity and/or outcome in pediatric ALL. In this review, we show that the majority of published reports do not find association or present opposite effect. Therefore, MTHFR C677T and A1298C polymorphisms do not seem to be good markers of MTX-related toxicity and/or outcome in pediatric ALL. The efforts should be focused on other genes, such as transporter genes or microRNA-related genes.