MicroRNA Expression Profile in Bone Marrow and Lymph Nodes in B-Cell Lymphomas.

Hodgkin's lymphomas (HL) and the majority of non-Hodgkin's lymphomas (NHL) derive from different stages of B-cell differentiation. MicroRNA (miRNA) expression profiles change during lymphopoiesis. Thus, miRNA expression analysis can be used as a reliable diagnostic tool to differentiate tumors. In addition, the identification of miRNA's role in lymphopoiesis impairment is an important fundamental task. The aim of this study was to analyze unique miRNA expression profiles in different types of B-cell lymphomas. We analyzed the expression levels of miRNA-18a, -20a, -96, -182, -183, -26b, -34a, -148b, -9, -150, -451a, -23b, -141, and -128 in lymph nodes (LNs) in the following cancer samples: HL (n = 41), diffuse large B-cell lymphoma (DLBCL) (n = 51), mantle cell lymphoma (MCL) (n = 15), follicular lymphoma (FL) (n = 12), and lymphadenopathy (LA) (n = 37), as well as bone marrow (BM) samples: HL (n = 11), DLBCL (n = 42), MCL (n = 14), FL (n = 16), and non-cancerous blood diseases (NCBD) (n = 43). The real-time RT-PCR method was used for analysis. An increase in BM expression levels of miRNA-26b, -150, and -141 in MCL (p < 0.01) and a decrease in BM levels of the miR-183-96-182 cluster and miRNA-451a in DLBCL (p < 0.01) were observed in comparison to NCBD. We also obtained data on increased LN levels of the miR-183-96-182 cluster in MCL (p < 0.01) and miRNA-18a, miRNA-96, and miRNA-9 in FL (p < 0.01), as well as decreased LN expression of miRNA-150 in DLBCL (p < 0.01), and miRNA-182, miRNA-150, and miRNA-128 in HL (p < 0.01). We showed that miRNA expression profile differs between BM and LNs depending on the type of B-cell lymphoma. This can be due to the effect of the tumor microenvironment.

The Profile of MicroRNA Expression in Bone Marrow in Non-Hodgkin's Lymphomas.

Non-Hodgkin's lymphomas (NHLs) are a heterogeneous group of malignant lymphomas that can occur in both lymph nodes and extranodal sites. Bone marrow (BM) is the most common site of extranodal involvement in NHL. The objective of this study is to determine the unique profile of miRNA expression in BM affected by NHL, with the possibility of a differential diagnosis of NHL from reactive BM changes and acute leukemia (AL). A total of 180 cytological samples were obtained by sternal puncture and aspiration biopsy of BM from the posterior iliac spine. All the cases were patients before treatment initiation. The study groups were NHL cases (n = 59) and AL cases (acute lymphoblastic leukemia (n = 25) and acute myeloid leukemia (n = 49)); the control group consisted of patients with non-cancerous blood diseases (NCBDs) (n = 48). We demonstrated that expression levels of miRNA-124, miRNA-221, and miRNA-15a are statistically significantly downregulated, while the expression level of let-7a is statistically significantly upregulated more than 2-fold in BM in NHL compared to those in AL and NCBD. ROC analysis revealed that let-7a/miRNA-124 is a highly sensitive and specific biomarker for a differential diagnosis of BM changes in NHL from those in AL and NCBD. Therefore, we conclude that analysis of miRNA expression levels may be a promising tool for early diagnosis of NHL.

Selection of reference genes for quantitative analysis of microRNA expression in three different types of cancer.

MicroRNAs (miRNAs) are promising biomarkers in cancer research. Quantitative PCR (qPCR), also known as real-time PCR, is the most frequently used technique for measuring miRNA expression levels. The use of this technique, however, requires that expression data be normalized against reference genes. The problem is that a universal internal control for quantitative analysis of miRNA expression by qPCR has yet to be known. The aim of this work was to find the miRNAs with stable expression in the thyroid gland, brain and bone marrow according to NanoString nCounter miRNA quantification data. As a results, the most stably expressed miRNAs were as follows: miR-361-3p, -151a-3p and -29b-3p in the thyroid gland; miR-15a-5p, -194-5p and -532-5p in the brain; miR-140-5p, -148b-3p and -362-5p in bone marrow; and miR-423-5p, -28-5p and -532-5p, no matter what tissue type. These miRNAs represent promising reference genes for miRNA quantification by qPCR.

Profiling 25 Bone Marrow microRNAs in Acute Leukemias and Secondary Nonleukemic Hematopoietic Conditions.

INTRODUCTION: The standard treatment of acute leukemias (AL) is becoming more efficacious and more selective toward the mechanisms via which to suppress hematologic cancers. This tendency in hematology imposes additional requirements on the identification of molecular-genetic features of tumor clones. MicroRNA (miRNA, miR) expression levels correlate with cytogenetic and molecular subtypes of acute leukemias recognized by classification systems. The aim of this work is analyzing the miRNA expression profiles in acute myeloblastic leukemia (AML) and acute lymphoblastic leukemia (ALL) and hematopoietic conditions induced by non-tumor pathologies (NTP). METHODS: A total of 114 cytological samples obtained by sternal puncture and aspiration biopsy of bone marrow (22 ALLs, 44 AMLs, and 48 NTPs) were analyzed by real-time PCR regarding preselected 25 miRNAs. For the classification of the samples, logistic regression was used with balancing of comparison group weights. RESULTS: Our results indicated potential feasibility of (i) differentiating ALL+AML from a nontumor hematopoietic pathology with 93% sensitivity and 92% specificity using miR-150:miR-21, miR-20a:miR-221, and miR-24:nf3 (where nf3 is a normalization factor calculated from threshold cycle values of miR-103a, miR-191, and miR-378); (ii) diagnosing ALL with 81% sensitivity and 81% specificity using miR-181b:miR-100, miR-223:miR-124, and miR-24:nf3; and (iii) diagnosing AML with 81% sensitivity and 84% specificity using miR-150:miR-221, miR-100:miR-24, and miR-181a:miR-191. CONCLUSION: The results presented herein allow the miRNA expression profile to de used for differentiation between AL and NTP, no matter what AL subtype.

Intratumoral Heterogeneity of Expression of 16 miRNA in Luminal Cancer of the Mammary Gland.

The purpose of this work is to determine the intratumoral distribution of miRNA expression profiles in luminal breast cancer (BC). The study included 33 certain BC cases of the luminal A or luminal B (Her2-) subtypes. The relative expression levels of miRNA-20a; -21; -125b; -126; -200b; -181a; -205; -221; -222; -451a; -99a; -145; -200a; -214; -30a; -191; and small nuclear RNAs U6, U54, and U58 were measured by RT-qPCR in four intratumor areas in each of 33 luminal BC specimens and in surrounding normal mammary gland tissues. Comparative analysis of miRNA expression levels between normal mammary gland tissue and different intratumor areas revealed that only four miRNAs (miRNA-21, -200b, -200a, -191) appear as consistently differentiating markers. A comparative analysis of miRNA expression levels between normal mammary gland tissue and the tumor border revealed statistically significant differences for ten miRNAs; 10 miRNAs show differential expression between normal mammary gland tissue and central tumor specimens; 9 miRNAs show differential expression between normal mammary gland tissue and tumor periphery 1; 13 miRNAs show differential expression between normal mammary gland tissue and tumor periphery 2. After comparing the tumor periphery 1 and tumor center, we found statistically significant differences in expression between five miRNAs and after comparing the tumor periphery 2 and tumor center, differences were observed for 12 miRNAs. MiRNA expression levels are subject to considerable variation, depending on the intratumor area. This may explain the inconsistency in miRNA expression estimates in BC coming from different laboratories.

Combined quantitation of HMGA2 mRNA, microRNAs, and mitochondrial-DNA content enables the identification and typing of thyroid tumors in fine-needle aspiration smears.

BACKGROUND: Analysis of molecular markers in addition to cytological analysis of fine-needle aspiration (FNA) samples is a promising way to improve the preoperative diagnosis of thyroid nodules. Nonetheless, in clinical practice, applications of existing diagnostic solutions based on the detection of somatic mutations or analysis of gene expression are limited by their high cost and difficulties with clinical interpretation. The aim of our work was to develop an algorithm for the differential diagnosis of thyroid nodules on the basis of a small set of molecular markers analyzed by real-time PCR. METHODS: A total of 494 preoperative FNA samples of thyroid goiters and tumors from 232 patients with known histological reports were analyzed: goiter, 105 samples (50 patients); follicular adenoma, 101 (48); follicular carcinoma, 43 (28); Hürthle cell carcinoma, 25 (11); papillary carcinoma, 121 (56); follicular variant of papillary carcinoma, 80 (32); and medullary carcinoma, 19 (12). Total nucleic acids extracted from dried FNA smears were analyzed for five somatic point mutations and two translocations typical of thyroid tumors as well as for relative concentrations of HMGA2 mRNA and 13 microRNAs and the ratio of mitochondrial to nuclear DNA by real-time PCR. A decision tree-based algorithm was built to discriminate benign and malignant tumors and to type the thyroid cancer. Leave-p-out cross-validation with five partitions was performed to estimate prediction quality. A comparison of two independent samples by quantitative traits was carried out via the Mann-Whitney U test. RESULTS: A minimum set of markers was selected (levels of HMGA2 mRNA and miR-375, - 221, and -146b in combination with the mitochondrial-to-nuclear DNA ratio) and yielded highly accurate discrimination (sensitivity = 0.97; positive predictive value = 0.98) between goiters with benign tumors and malignant tumors and accurate typing of papillary, medullary, and Hürthle cell carcinomas. The results support an alternative classification of follicular tumors, which differs from the histological one. CONCLUSIONS: The study shows the feasibility of the preoperative differential diagnosis of thyroid nodules using a panel of several molecular markers by a simple PCR-based method. Combining markers of different types increases the accuracy of classification.

miRNA profiling, detection of BRAF V600E mutation and RET-PTC1 translocation in patients from Novosibirsk oblast (Russia) with different types of thyroid tumors.

BACKGROUND: The postoperative typing of thyroid lesions, which is instrumental in adequate patient treatment, is currently based on histologic examination. However, it depends on pathologist's qualification and can be difficult in some cases. Numerous studies have shown that molecular markers such as microRNAs and somatic mutations may be useful to assist in these cases, but no consensus exists on the set of markers that is optimal for that purpose. The aim of the study was to discriminate between different thyroid neoplasms by RT-PCR, using a limited set of microRNAs selected from literature. METHODS: By RT-PCR we evaluated the relative levels of 15 microRNAs (miR-221, -222, -146b, -181b, -21, -187, -199b, -144, -192, -200a, -200b, -205, -141, -31, -375) and the presence of BRAF(V600E) mutation and RET-PTC1 translocation in surgically resected lesions from 208 patients from Novosibirsk oblast (Russia) with different types of thyroid neoplasms. Expression of each microRNA was normalized to adjacent non-tumor tissue. Three pieces of lesion tissue from each patient (39 goiters, 41 follicular adenomas, 16 follicular thyroid cancers, 108 papillary thyroid cancers, 4 medullary thyroid cancers) were analyzed independently to take into account method variation. RESULTS: The diagnostic classifier based on profiling of 13 microRNAs was proposed, with total estimated accuracy varying from 82.7 to 99% for different nodule types. Relative expression of six microRNAs (miR-146b, -21, -221, -222, 375, -199b) appeared significantly different in BRAF(V600E)-positive samples (all classified as papillary thyroid carcinomas) compared to BRAF(V600E)-negative papillary carcinoma samples. CONCLUSIONS: The results confirm practical feasibility of using molecular markers for typing of thyroid neoplasms and clarification of controversial cases.

DNA copy-number control through inhibition of replication fork progression.

Proper control of DNA replication is essential to ensure faithful transmission of genetic material and prevent chromosomal aberrations that can drive cancer progression and developmental disorders. DNA replication is regulated primarily at the level of initiation and is under strict cell-cycle regulation. Importantly, DNA replication is highly influenced by developmental cues. In Drosophila, specific regions of the genome are repressed for DNA replication during differentiation by the SNF2 domain-containing protein SUUR through an unknown mechanism. We demonstrate that SUUR is recruited to active replication forks and mediates the repression of DNA replication by directly inhibiting replication fork progression instead of functioning as a replication fork barrier. Mass spectrometry identification of SUUR-associated proteins identified the replicative helicase member CDC45 as a SUUR-associated protein, supporting a role for SUUR directly at replication forks. Our results reveal that control of eukaryotic DNA copy number can occur through the inhibition of replication fork progression.

Drosophila SUUR protein associates with PCNA and binds chromatin in a cell cycle-dependent manner.

Drosophila SUUR (Suppressor of UnderReplication) protein was shown to regulate the DNA replication elongation process in endocycling cells. This protein is also known to be the component of silent chromatin in polyploid and diploid cells. To mark the different cell cycle stages, we used immunostaining patterns of PCNA, the main structural component of replication fork. We demonstrate that SUUR chromatin binding is dynamic throughout the endocyle in Drosophila salivary glands. We observed that SUUR chromosomal localization changed along with PCNA pattern and these proteins largely co-localized during the late S-phase in salivary glands. The hypothesized interaction between SUUR and PCNA was confirmed by co-immunoprecipitation from embryonic nuclear extracts. Our findings support the idea that the effect of SUUR on replication elongation depends on the cell cycle stage and can be mediated through its physical interaction with replication fork.

Molecular characterization of the singed wings locus of Drosophila melanogaster.

BACKGROUND: Hormones frequently guide animal development via the induction of cascades of gene activities, whose products further amplify an initial hormonal stimulus. In Drosophila the transformation of the larva into the pupa and the subsequent metamorphosis to the adult stage is triggered by changes in the titer of the steroid hormone 20-hydroxyecdysone. singed wings (swi) is the only gene known in Drosophila melanogaster for which mutations specifically interrupt the transmission of the regulatory signal from early to late ecdysone inducible genes. RESULTS: We have characterized singed wings locus, showing it to correspond to EG:171E4.2 (CG3095). swi encodes a predicted 68.5-kDa protein that contains N-terminal histidine-rich and threonine-rich domains, a cysteine-rich C-terminal region and two leucine-rich repeats. The SWI protein has a close homolog in D. melanogaster, defining a new family of SWI-like proteins, and is conserved in D. pseudoobscura. A lethal mutation, swit476, shows a severe disruption of the ecdysone pathway and is a C>Y substitution in one of the two conserved CysXCys motifs that are common to SWI and the Drosophila Toll-4 protein. CONCLUSIONS: It is not entirely clear from the present molecular analysis how the SWI protein may function in the ecdysone induced cascade. Currently all predictions agree in that SWI is very unlikely to be a nuclear protein. Thus it probably exercises its control of "late" ecdysone genes indirectly. Apparently the genetic regulation of ecdysone signaling is much more complex then was previously anticipated.