The miR-1206 microRNA variant is associated with methotrexate-induced oral mucositis in pediatric acute lymphoblastic leukemia

The genetic variants of miR-1206 and miR-125b in breast cancer patients: in vitro and in silico analysis

BACKGROUND

This study aimed to investigate the association of rs12976445 polymorphism in the promoter region of miR-125a and rs2114358 in the precursor region of miR-1206 to breast cancer susceptibility.

METHOD

A total of 230 participants (110 breast cancer and 120 controls) enrolled in this study and extracted genomic DNA. The genotypes were determined by the Tetra-ARMS method. The allele and genotype frequencies were determined.

RESULTS

Allele variation in the rs12976445 (miR-125a) sequence increased the risk of breast cancer; a significant relationship was observed between breast cancer and allele change in individuals with the C allele (p = 0.01). However, allele variation in the rs2114358 (miR-1206) decreased the risk of breast cancer in individuals with allele A (p = 0.01). In silico study showed that allele change was associated with a reduction in structural stability.

CONCLUSION

Therefore, the rs12976445 variant can be considered a risk factor for breast cancer, and the rs2114358 variant is a protective factor against it.

MicroRNA Expression Profiles in Human Samples and Cell Lines Revealed Nine miRNAs Associated with Cisplatin Resistance in High-Grade Serous Ovarian Cancer

Metastasis and drug resistance are major contributors to cancer-related fatalities worldwide. In ovarian cancer (OC), a staggering 70% develop resistance to the front-line therapy, cisplatin. Despite proposed mechanisms, the molecular events driving cisplatin resistance remain unclear. Dysregulated microRNAs (miRNAs) play a role in OC initiation, progression, and chemoresistance, yet few studies have compared miRNA expression in OC samples and cell lines. This study aimed to identify key miRNAs involved in the cisplatin resistance of high-grade-serous-ovarian-cancer (HGSOC), the most common gynecological malignancy. MiRNA expression profiles were conducted on RNA isolated from formalin-fixed-paraffin-embedded human ovarian tumor samples and HGSOC cell lines. Nine miRNAs were identified in both sample types. Targeting these with oligonucleotide miRNA inhibitors (OMIs) reduced proliferation by more than 50% for miR-203a, miR-96-5p, miR-10a-5p, miR-141-3p, miR-200c-3p, miR-182-5p, miR-183-5p, and miR-1206. OMIs significantly reduced migration for miR-183-5p, miR-203a, miR-296-5p, and miR-1206. Molecular pathway analysis revealed that the nine miRNAs regulate pathways associated with proliferation, invasion, and chemoresistance through PTEN, ZEB1, FOXO1, and SNAI2. High expression of miR-1206, miR-10a-5p, miR-141-3p, and miR-96-5p correlated with poor prognosis in OC patients according to the KM plotter database. These nine miRNAs could be used as targets for therapy and as markers of cisplatin response.

Attempts to Understand Oral Mucositis in Head and Neck Cancer Patients through Omics Studies: A Narrative Review

Oral mucositis (OM) is a common and clinically impactful side effect of cytotoxic cancer treatment, particularly in patients with head and neck squamous cell carcinoma (HNSCC) who undergo radiotherapy with or without concomitant chemotherapy. The etiology and pathogenic mechanisms of OM are complex, multifaceted and elicit both direct and indirect damage to the mucosa. In this narrative review, we describe studies that use various omics methodologies (genomics, transcriptomics, microbiomics and metabolomics) in attempts to elucidate the biological pathways associated with the development or severity of OM. Integrating different omics into multi-omics approaches carries the potential to discover links among host factors (genomics), host responses (transcriptomics, metabolomics), and the local environment (microbiomics).

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.

Polymorphism but not methylation status in the vitamin D receptor gene contributes to oral mucositis in children

OBJECTIVE

To investigate the relationship between the polymorphisms rs1544410 (BsmI), rs2228570 (FokI) and rs731236 (TaqI) and DNA methylation status in the VDR gene (vitamin D receptor) with oral mucositis (OM) in oncopaediatric patients treated with methotrexate (MTX®).

METHODS

The population comprised healthy patients with haematological malignancies aged between 5 and 19 years. An evaluation of oral conditions was performed using the Oral Assessment Guide. Demographic, clinical, biochemical and haematological data were obtained from medical records. Genomic DNA from oral mucosal cells was used for the analysis of polymorphisms (n = 102) (PCR-restriction fragment length polymorphism) and DNA methylation (n = 81) (methylation-specific PCR).

RESULTS

Males predominated (57.8%), and the mean age was 10.3 years (±4.7). OM affected 84.3% of patients, of which 53.1% developed severe oral mucositis (SOM). Patients with OM had lower platelet and leukocyte counts (p < 0.05). The G allele of rs1544410 (p = 0.040) and the CT genotype of rs2228570 polymorphisms were associated with SOM (p = 0.038). A partially methylated status in the VDR promoter was found in all patients.

CONCLUSION

OM is associated with lower leukocyte and platelet counts. SOM is associated with the rs1544410 and rs2228570 polymorphisms. The methylation status of the VDR is not associated with inflammation or exposure to MTX®.

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.

Holistic Approach of a Leukemic Child Suffering from Oral Mucositis with Coinfections: A Case Report

Oral mucositis (OM) is a life-threatening side effect of chemo-radiotherapy. OM can provide a portal of entry for many microorganisms as coinfections which potentially generate other oral lesions. This case report describes a holistic approach to obtaining the successful treatment of OM with necrotizing ulcerative stomatitis (NUS) and oral candidiasis as coinfections in pediatric acute lymphoblastic leukemia (ALL). A 2-year-8-month-old boy was referred from the Pediatrics Department at Dr. Hasan Sadikin General Hospital with the chief complaint of canker sore and eating difficulty for the past two weeks. He had undergone the twelfth cycle of the last chemotherapy using methotrexate regimen. Extraoral examination revealed anemic conjunctiva, icteric sclera, and dry lips. Well-defined irregular multiple ulcers covered by yellowish to grayish pseudomembranous were found on the upper and lower labial mucosa, right and left buccal mucosa, tongue, palate, and gingiva. Potassium hydroxide (KOH) examination showed fungi in the oral lesions smear. The established diagnosis was OM with NUS and oral candidiasis as coinfections. Debridement was done using chlorine dioxide-zinc and 0.2% chlorhexidine gluconate. We collaborated with the pediatrician who prescribed ceftazidime, meropenem, and fluconazole, and also with parents. The holistic approach is beneficial and important in improving quality of life and supporting the successful treatment of OM with coinfections.

Circ_0043256 upregulates KLF2 expression by absorbing miR-1206 to suppress the tumorigenesis of lung cancer

BACKGROUND

Circular RNAs (circRNAs) have been reported to play roles in lung cancer development. The purpose of this work was to explore the function and mechanism of circ_0043256 in lung cancer tumorigenesis.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR) and western blot were used for the detection of the levels of genes and proteins. Cell growth, angiogenesis ability, migration, and invasion were analyzed by using 5-ethynyl-2'-deoxyuridine (EdU) assay, flow cytometry, tube formation assay, transwell assay, and murine xenograft model, respectively. The target between miR-1206 and circ_0043256 or Krüppel-like factor 2 (KLF2) was verified by dual-luciferase reporter assay.

RESULTS

Circ_0043256 was a stable circRNA, which was found to be decreased in lung cancer tissues and cells. Functionally, forced expression of circ_0043256 suppressed lung cancer cell growth, angiopoiesis, migration, and invasion. Mechanistically, circ_0043256 directly bound to miR-1206 and miR-1206 targeted KLF2, circ_0043256 could regulate KLF2 expression via absorbing miR-1206. Rescue assay showed that miR-1206 overexpression reversed the anticancer effects of circ_0043256 on lung cancer cells. Moreover, inhibition of miR-1206 could suppress the malignant phenotypes of lung cancer cells, which was attenuated by KLF2 knockdown. Pre-clinically, lentivirus-mediated circ_0043256 overexpression impeded lung cancer growth in nude mice.

CONCLUSION

Forced expression of circ_0043256 could impede the tumorigenesis of lung cancer via miR-1206/KLF2 axis, indicating a potential therapeutic approach for lung cancer.

Genetic variants found in paediatric oncology patients with severe chemotherapy-induced toxicity: A case series

Paediatric oncology patients who develop severe chemotherapy-induced toxicity that requires dose reduction, delay or termination of treatment are at risk of decreased treatment efficacy. Previous research has provided evidence that genetic variants in TPMT, NUDT15, UGT1A1 and DPYD are associated with toxicity of anticancer drugs. This led to pharmacogenetic guidelines that are integrated into clinical practice in paediatric oncology. Recently, novel genetic variants have been associated with a higher risk of developing chemotherapy-induced toxicity. In this case series, we selected 21 novel variants and genotyped these in nine patients with excessive chemotherapy-induced toxicity using whole exome sequencing or micro-array data. We observed that six out of nine patients carried at least one variant that, according to recent studies, potentially increased the risk of developing methotrexate- or vincristine-induced toxicity. As patient-derived genetic data are becoming widely accessible in paediatric oncology, these variants could potentially enter clinical practice to mitigate chemotherapy-induced toxicity.

Implication of microRNAs in Carcinogenesis with Emphasis on Hematological Malignancies and Clinical Translation

MicroRNAs (miRNAs) are evolutionarily conserved small non-coding RNAs, that are involved in the multistep process of carcinogenesis, contributing to all established hallmarks of cancer. In this review, implications of miRNAs in hematological malignancies and their clinical utilization fields are discussed. As components of the complex regulatory network of gene expression, influenced by the tissue microenvironment and epigenetic modifiers, miRNAs are “micromanagers” of all physiological processes including the regulation of hematopoiesis and metabolic pathways. Dysregulated miRNA expression levels contribute to both the initiation and progression of acute leukemias, the metabolic reprogramming of malignantly transformed hematopoietic precursors, and to the development of chemoresistance. Since they are highly stable and can be easily quantified in body fluids and tissue specimens, miRNAs are promising biomarkers for the early detection of hematological malignancies. Besides novel opportunities for differential diagnosis, miRNAs can contribute to advanced chemoresistance prediction and prognostic stratification of acute leukemias. Synthetic oligonucleotides and delivery vehicles aim the therapeutic modulation of miRNA expression levels. However, major challenges such as efficient delivery to specific locations, differences of miRNA expression patterns between pediatric and adult hematological malignancies, and potential side effects of miRNA-based therapies should be considered.

Genetic polymorphisms of genes involved in oxidative stress and inflammatory management in oncopediatric patients with chemo-induced oral mucositis

Oral mucositis (OM) is a painful inflammatory oral condition that affects children who undergo chemotherapy. Oxidative stress is a known OM mediator and pro-inflammatory cytokines contribute to the amplification of the immune response.

Genetic variants associated with methotrexate-induced mucositis in cancer treatment: A systematic review and meta-analysis

Methotrexate (MTX), an important chemotherapeutic agent, is often accompanied with mucositis. The occurrence and severity are unpredictable and show large interindividual variability. In this study, we review and meta-analyze previously studied genetic variants in relation to MTX-induced mucositis. We conducted a systematic search in Medline and Embase. We included genetic association studies of MTX-induced mucositis in cancer patients. A meta-analysis was conducted for single nucleotide polymorphisms (SNPs) for which at least two studies found a statistically significant association. A total of 34 SNPs were associated with mucositis in at least one study of the 57 included studies. Two of the seven SNPs included in our meta-analysis were statistically significantly associated with mucositis: MTHFR c.677C > T (recessive, grade ≥3 vs grade 0-2, OR 2.53, 95 %CI [1.48-4.32], False Discovery Rate[FDR]-corrected p-value 0.011) and MTRR c.66A > G (overdominant, grade ≥1 vs grade 0, OR 2.08, 95 %CI [1.16-3.73], FDR-corrected p-value 0.042).

Oral mucositis: the hidden side of cancer therapy

Inflammation response of epithelial mucosa to chemo- radiotherapy cytotoxic effects leads to mucositis, a painful side effect of antineoplastic treatments. About 40% of the patients treated with chemotherapy develop mucositis; this percentage rises to about 90% for head and neck cancer patients (HNC) treated with both chemo- and radiotherapy. 19% of the latter will be hospitalized and will experience a delay in antineoplastic treatment for high-grade mucositis management, resulting in a reduction of the quality of life, a worse prognosis and an increase in patient management costs. Currently, several interventions and prevention guidelines are available, but their effectiveness is uncertain. This review comprehensively describes mucositis, debating the impact of standard chemo-radiotherapy and targeted therapy on mucositis development and pointing out the limits and the benefits of current mucositis treatment strategies and assessment guidelines. Moreover, the review critically examines the feasibility of the existing biomarkers to predict patient risk of developing oral mucositis and their role in early diagnosis. Despite the expression levels of some proteins involved in the inflammation response, such as TNF-α or IL-1β, partially correlate with mucositis process, their presence does not exclude others mucositis-independent inflammation events. This strongly suggests the need to discover biomarkers that specifically feature mucositis process development. Non-coding RNAs might hold this potential.

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.

Pharmacogenomics as a Tool to Limit Acute and Long-Term Adverse Effects of Chemotherapeutics: An Update in Pediatric Oncology

In the past decades, new cancer treatments have been introduced in pediatric oncology leading to improvement in clinical outcomes and survival rates. However, due to inter-individual differences, some children experience severe chemotherapy-induced toxicities or a poor clinical outcome. An explanation for the diversity in response to chemotherapy is genetic variation, leading to differences in expression and activity of metabolizing and transport enzymes as well as drug targets. Pharmacogenetic testing has emerged as a promising tool to predict and limit acute and long-term adverse effects in patients. However, in pediatric oncology, limited number of patients and a considerable diversity in study results complicate the interpretation of test results and its clinical relevance. With this review, we provide an overview of new developments over the past four years regarding relevant polymorphisms related to toxicity in pediatric oncology. The following chemotherapeutics and associated toxicities are discussed: alkylating agents, anthracyclines, asparaginase, methotrexate, platinum compounds, steroids, thiopurines, topoisomerase inhibitors, and vinca alkaloids. Our review identifies several questions regarding the role of genetic variants in chemotherapy-induced toxicities. Ambiguities in the literature stem from small population sizes, differences in (statistical) interpretation and variations in sequencing technologies as well as different clinical outcome definitions. Standardization of clinical outcome data and toxicity definitions within electronic health records combined with the increased availability of genomic sequence techniques in clinical practice will help to validate these models in upcoming years.

Prediction of mucositis risk secondary to cancer therapy: a systematic review of current evidence and call to action

PURPOSE

Despite advances in personalizing the efficacy of cancer therapy, our ability to identify patients at risk of severe treatment side effects and provide individualized supportive care is limited. This is particularly the case for mucositis (oral and gastrointestinal), with no comprehensive risk evaluation strategies to identify high-risk patients. We, the Multinational Association for Supportive Care in Cancer/International Society for Oral Oncology (MASCC/ISOO) Mucositis Study Group, therefore aimed to systematically review current evidence on that factors that influence mucositis risk to provide a foundation upon which future risk prediction studies can be based.

METHODS

We identified 11,018 papers from PubMed and Web of Science, with 197 records extracted for full review and 113 meeting final eligibility criteria. Data were then synthesized into tables to highlight the level of evidence for each risk predictor.

RESULTS

The strongest level of evidence supported dosimetric parameters as key predictors of mucositis risk. Genetic variants in drug-metabolizing pathways, immune signaling, and cell injury/repair mechanisms were also identified to impact mucositis risk. Factors relating to the individual were variably linked to mucositis outcomes, although female sex and smoking status showed some association with mucositis risk.

CONCLUSION

Mucositis risk reflects the complex interplay between the host, tumor microenvironment, and treatment specifications, yet the large majority of studies rely on hypothesis-driven, single-candidate approaches. For significant advances in the provision of personalized supportive care, coordinated research efforts with robust multiplexed approaches are strongly advised.

The role of microRNAs in acute lymphoblastic leukaemia: From biology to applications

MicroRNAs (miRNAs) that are characterized by small, noncoding RNA have an essential role in the pathogenesis of human diseases, including cancer. Furthermore, miRNAs, as a new paradigm of epigenetic regulators, play an important role in normal development and cellular function. This literature review summarizes the recurrent mechanism of gene regulation through miRNAs and, consequently, the impact of regulated genes on different cellular processes, including proliferation, metastasis, prognosis, and apoptosis. Additionally, what is important to note is that the expression of miRNAs in various cancer cells is different, and miRNAs have various target genes in various cancers. Accordingly, a proper understanding of gene regulation by miRNAs contributes to new perspectives in miRNA-based therapeutic strategies. SIGNIFICANCE OF THE STUDY: MiRNAs are considered as a crucial regulator of gene expression. The genes also play an important role in the expression of miRNAs; as a result, there is a relationship between them. In recent years, targeted therapy with miRNAs has been a significant challenge. Studying the mechanisms through which miRNAs regulate various cancer cell processes, including apoptosis, proliferation, and metastasis, is very critical in the treatment of cancer through miRNAs. Definitely, a proper understanding of the impacts of aberrant expression of miRNAs on cancer cell processes leads to new therapeutic strategies in the targeted therapy with miRNAs.

MicroRNA Determines the Fate of Intestinal Epithelial Cell Differentiation and Regulates Intestinal Diseases

The rapid self-renewal of intestinal epithelial cells enhances intestinal function, promotes the nutritional needs of animals and strengthens intestinal barrier function to resist the invasion of foreign pathogens. MicroRNAs (miRNAs) are a class of short-chain, non-coding RNAs that regulate stem cell proliferation and differentiation by down-regulating hundreds of conserved target genes after transcription via seed pairing to the 3' untranslated regions. Numerous studies have shown that miRNAs can improve intestinal function by participating in the proliferation and differentiation of different cell populations in the intestine. In addition, miRNAs also contribute to disease regulation and therefore not only play a vital role in the gastrointestinal disease management but also act as blood or tissue biomarkers of disease. As changes to the levels of miRNAs can change cell fates, miRNA-mediated gene regulation can be used to update therapeutic strategies and approaches to disease treatment.

The Role of MicroRNA in Paediatric Acute Lymphoblastic Leukaemia: Challenges for Diagnosis and Therapy

Acute lymphoblastic leukaemia (ALL) is the most common cancer of childhood. Although the overall survival of children with ALL is now more than 90%, leukaemia remains one of the leading causes of death from disease. In developed countries, the overall survival of patients with ALL has increased to more than 80%; however, those children cured from ALL still show a significant risk of short- and long-term complications as a consequence of their treatment. Accordingly, there is a need not only to develop new methods of diagnosis and prognosis but also to provide patients with less toxic therapies. MicroRNAs (miRNAs) are small ribonucleic acids (RNA), usually without coding potential, that regulate gene expression by directing their target messenger RNAs (mRNAs) for degradation or translational suppression. In paediatric ALL, several miRNAs have been observed to be overexpressed or underexpressed in patient cohorts compared to healthy individuals, while numerous studies have identified specific miRNAs that can be used as biomarkers to diagnose ALL, classify it into subgroups, and predict prognosis. Likewise, a variety of miRNAs identify as candidate targets for treatment, although there are numerous obstacles to overcome before their clinical use in patients. Here, we summarise the roles played by different miRNAs in childhood leukaemia, focussing primarily on their use as diagnostic tools and potential therapeutic targets, as well as a role in predicting treatment outcome. Finally, we discuss the potential roles of miRNA in immunotherapy and the novel contributions made by gut miRNAs to regulation of the host microbiome.

Predicting mucositis risk associated with cytotoxic cancer treatment regimens: rationale, complexity, and challenges

PURPOSE OF REVIEW

The goals of this review are to describe the complexity of factors influencing the risk of cancer regimen-related mucosal injury (CRRMI), to evaluate the contribution of the innate immune response to CRRMI risk, to compare the concordance of genome analytics in describing mechanism and risk, and to determine if common biological pathways are noted when CRRMI is compared to a disease with a similar phenotype.

RECENT FINDINGS

The pathogenesis of and risk for CRRMI are complex and influenced by multiple intrinsic and extrinsic factors. It is incumbent on analyses to recognize the likelihood that the interplay and cross-talk of synergistically expressed factors is critical and that the contributing weights of these factors is not uniform from patient to patient. Genomically derived analyses imply final common pathways are implicit in phenotype expression.

SUMMARY

The identification of specific factors (both genomic and otherwise) which contribute to CRRMI risk represents an important opportunity to apply principles of precision medicine to the management of regimen-related toxicities.

The Association of rs2114358 in the miR-1206 Polymorphism to Chronic Myeloid Leukemia

INTRODUCTION

Association studies with factor candidates have advised that single nucleotide polymorphisms (SNPs) could also be related to CML progression and to the response to medical care. Genetic variation in miR-1206 of both derived and neighborhood SNPs process genes will contribute to the predisposition to cancer. The role of those with the risk of CML has not been extensively studied. Therefore, the aim of this study was to evaluate whether polymorphisms in rs2114358 in pre-miRNAs process genes contribute to the risk of CML.

METHODS

A cross-sectional study was conducted during the period of March 2016 to October 2017 in Khartoum state teaching hospitals. The study population included a total of 420 patients who were previously diagnosed of having CML and 220 cancer-free controls of both gender and were of the same age range. Peripheral blood and bone marrow aspiration samples were collected from patients (254 males, 166 females; median age 58.5 years, range from less than 50 and above 50 years old) and investigated after written informed consent was obtained. Patients were in chronic phase (n=212), accelerated phase (n=125), and blast (n=83). All the patients were under treatment using chemotherapy regiments. The rs2114358 SNP in pre-miRNA was selected for genotyping.

RESULTS

The genotyping success rate was 98.3%. Genotype frequencies of the derived SNP and the neighborhood rs2114358 of miR-1206 compared to the controls were significantly different under Hardy-Weinberg Equilibrium (P=0.0001 and 0.0001 respectively). Significant differences were found in allele distributions of this SNP (P<0.01 and P<0.01). In total, the derived variant C allele of rs2114358 (OR=0.168, 95% CI=0.13-0.22) and G allele of neighborhood rs2114358 (OR=0.561, 95% CI=0.44-0.72) in patients' group were associated with an increased risk of CML compared to a control group. Patients with rs2114358 CC genotype (P = 0.0001) or TC (P = 0.0001) and the neighborhood rs2114358 GA genotype (P = 0.0460) or GG (P = 0.0093) were obviously much higher than that of the TT and AA genotype's patients.

CONCLUSION

In conclusion, we discovered the association of SNP rs2114358 in miR-1206 with the risk of CML patients, though more investigations are still required to understand the regulative mechanisms of this miR SNP with the target genes resulting in its dysregulation.

Involvement of miRNA polymorphism in mucositis development in childhood acute lymphoblastic leukemia treatment

Aim: Mucositis, linked to methotrexate, daunorubicin or cyclophosphamide, is a frequent childhood acute lymphoblastic leukemia (ALL) therapy side effect. miRNAs regulate the expression of pharmacokinetic/pharmacodynamic pathway genes. SNPs in miRNAs could affect their levels or function, and affect their pharmacokinetic/pharmacodynamic pathway target genes. Our aim was to determine the association between miRNA genetic variants targeting mucositis-related genes and mucositis-developing risk. Patients & methods: We analyzed 160 SNPs in 179 Spanish children with B-cell precursor ALL homogeneously treated with LAL/SHOP protocols. Results: We identified three SNPs in miR-4268, miR-4751 and miR-3117 associated with mucositis, diarrhea and vomiting, respectively. Conclusion: The effect of these SNPs on genes related to drug pharmacokinetics/pharmacodynamics could explain mucositis, diarrhea and vomiting development during ALL therapy.

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.

Circulating miRNAs as biomarkers in diffuse large B-cell lymphoma: a systematic review

Diffuse large B-cell lymphoma (DLBCL) is an aggressive and heterogeneous malignancy, with highly variable outcomes among patients. Although classification and prognostic tools have been developed, standard therapy still fails in 30-40% of patients. Hence, identification of novel biomarkers is needed. Recently, circulating microRNAs (miRNAs) have been suggested as non-invasive biomarkers in cancer. Our aim was to review the potential role of circulating miRNAs as biomarkers for diagnosis, classification, prognosis, and treatment response in DLBCL.

We performed a search in PubMed using the terms [((‘Non-coding RNA’) OR (‘microRNA’ OR ‘miRNA’ OR ‘miR’) OR (‘exosome’) OR (‘extracellular vesicle’) OR (‘secretome’)) AND (‘Diffuse large B cell lymphoma’ OR ‘DLBCL’)] to identify articles that evaluated the impact of circulating miRNAs as diagnosis, subtype, treatment response or prognosis biomarkers in DLBCL in human population.

Among the twelve articles that met the inclusion criteria, eleven considered circulating miRNAs as biomarkers for diagnosis, two for classification, and five for prognosis or treatment response. The limited number of studies performed and lack of consistency in results make it difficult to draw conclusions about the role of circulating miRNAs as non-invasive biomarkers in DLBCL. Although the preliminary associations observed seem promising, the only consistent result is the upregulation of mir-21 in DLBCL patients, which could be a biomarker for diagnosis. Further studies are needed.

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.

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.

The SNPs in pre-miRNA are related to the response of capecitabine-based therapy in advanced colon cancer patients

The single nucleotide polymorphisms (SNPs) in the microRNA precursor (pre-miRNA) may modulate the posttranscriptional regulation of gene expression and explain individual sensitivity to chemotherapy. Here we investigated the correlation between 23 SNPs in the pre-miRNA and the efficacy of capecitabine-based chemotherapy in 274 advanced colon cancer patients. Statistical analysis indicated that much more patients with rs744591 A/C(48.03%), C/C (53.45%) or C allele (49.73%) responded to the chemotherapy than those with the A/A genotype (33.71%). The response rates of rs745666 G/C heterozygous patients (35.25%) and C allele carriers (39.69%) were apparently less than that of the G/G homozygous patients (56.25%). Moreover, three SNPs rs2114358, rs35770269, and rs73239138 were significantly associated with the occurrence of side effects of chemotherapy. The patients with rs2114358 C allele (OR = 2.016) or rs35770269 T allele (OR = 2.299) were much more prone to endure adverse events. However, the incidence of side effect was lower in the patients carrying rs73239138 A allele than those with G/G genotype (OR = 0.500). Our findings demonstrate that genetic variations in pre-miRNA may influence the efficacy of capecitabine-based chemotherapy in advanced colon cancer patients.

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.