Estimation of the level of anthropogenic impact based on the determination of radionuclides and heavy metals in sediments taken from Rybnik reservoir, Poland.

The aim of the study was to estimate the degree of anthropogenic risk by evaluating the level of the contamination of sediments collected from the Rybnik reservoir. The results of the determination of radionuclides (137Cs, 40K, 228Th, 228Ra, 226Ra, 210Pb, 238U) and heavy metals (Zn, Cd, Pb, Cu, Cr, Ni) were presented. The Rybnik reservoir is located in a highly urbanised area, the Lower Silesian Voivodeship in Poland. Radionuclides (137Cs, 40K, 228Th, 228Ra, 226Ra, 210Pb, 238U) were measured using gamma spectrometry. The heavy metal (Zn, Cd, Pb, Cu, Ni and Cr) content was determined using an inductively coupled plasma optical emission spectrophotometer (ICP-OES). The classification of sediment pollution was made on the basis of geochemical and ecotoxicological indices. Radioactivity was varied with the highest for 40K (more than 200 Bq·kg-1). The concentrations for the remaining radionuclides were mostly below 20 Bq·kg-1. At the inlet zone (no. 9) an increase in radioactivity of each radioisotope was observed. The values of heavy metals from the lowest to the highest total amount in the sediments were as follows: Cd < Cr < Pb < Ni < Cu < Zn. The sediments of the reservoir are largely contaminated with Cu, but the sediments generally are contaminated to an average degree. Most pollutants accumulate in the inlet zone and near the dam wall. The content of artificial radionuclides, as well as the geochemical and ecological indicators used, can serve as an indicator of the level of anthropopressure in the vicinity of the Rybnik reservoir.

Perioperative Management of Dental Surgery Patients Chronically Taking Antithrombotic Medications.

The development of medicine is based not only on the introduction of new methods of treatment, but also on the use of increasingly effective drugs, including antithrombotic drugs. Drugs that inhibit the activity of platelets (antiplatelet and anti-aggregating drugs) and pharmaceuticals that inhibit the activity of plasma coagulation factors (anticoagulants) are used in antithrombotic therapy. In our daily practice we encounter patients who take chronic antiplatelet or anticoagulant drugs. However, more and more often we are dealing with patients who are treated with two antiplatelet drugs, an antiplatelet and an anticoagulant or even undergoing triple antithrombotic therapy. When preparing the patient for invasive craniofacial procedures, it should be assessed whether the temporary discontinuation of antithrombotic treatment due to the fear of excessive perioperative bleeding is justified and will not result in life-threatening thromboembolic complications. The authors discuss in detail the medications used in modern antithrombotic treatment and present a perioperative management procedure with a patient who takes l4 z of these medications chronically.

Effects of Piptoporus betulinus Ethanolic Extract on the Proliferation and Viability of Melanoma Cells and Models of Their Cell Membranes.

Piptoporus betulinus is a fungus known for its medicinal properties. It possesses antimicrobial, anti-inflammatory, and anti-cancer activity. In this study, several tests were performed to evaluate the cytotoxic effect of the ethanolic extract of Piptoporus betulinus on two melanoma human cell lines, WM115 primary and A375 metastatic cell lines, as well as Hs27 human skin fibroblasts. The extract proved to affect cancer cells in a dose-dependent manner, and at the same time showed a low cytotoxicity towards the normal cells. The total phenolic content (TPC) was determined spectrophotometrically by the Folin-Ciocalteu method (F-C), and the potential antioxidant activity was measured by ferric-reducing antioxidant power (FRAP) assay. One of the active compounds in the extract is betulin. It was isolated and then its cytotoxic activity was compared to the results obtained from the Piptoporus betulinus extract. To further understand the mechanism of action of the extract's anticancer activity, tests on model cell membranes were conducted. A model membrane of a melanoma cell was designed and consisted of 1,2-dimyristoyl-sn-glycero-3-phosphocholine, disialoganglioside-GD1a and cholesterol: DMPC:GD1a:chol (5:2:3 mole ratio). Changes in a Langmuir monolayer were observed and described based on Π-Amol isotherm and compressibility modulus changes. LB lipid bilayers were deposited on a hydrophilic gold substrate and analyzed by IR and X-ray photoelectron spectroscopy. Our study provides new data on the effect of Piptoporus betulinus extract on melanoma cells and its impact on the model of melanoma plasma membranes.

Extreme Situation Experienced by Dental Students of the Medical University of Silesia Due to the SARS-CoV-2 Epidemic during the First Lockdown.

The pandemic declared in many countries in 2020 due to COVID-19 led to the freezing of economies and the introduction of distance learning in both schools and universities. This unusual situation has affected the mental state of citizens, which has the potential to lead to the development of post-traumatic stress and depression. This study aimed to assess the level of stress in dental students in the context of the outbreak of the SARS-CoV-2 virus pandemic. A survey on the PSS-10 scale was prepared to measure the level of perceived stress. The study included 164 dental students at the Faculty of Medical Sciences of the Medical University of Silesia in Katowice, Poland. The results showed the impact of COVID-19 on the stress of students, with 67.7% reporting high levels of stress. The study also revealed that stress was higher among older female students. This paper recommends that the university provide more intensive psychological care as psychological first aid strategies in epidemics or natural disasters and to consider telemedicine in order to deliver services due to the limitations of the pandemic.

Evaluation of the Most Stressful Dental Treatment Procedures of Conservative Dentistry among Polish Dental Students.

BACKGROUND: Dental schools are considered to be a very stressful environment; the stress levels of dental students are higher than those of the general population. The aim of this study was to assess the level of stress among dental students while performing specific dental procedures. METHODS: A survey was conducted among 257 participants. We used an original questionnaire, which consisted of 14 questions assigned to three categories: I-Diagnosis, II-Caries Treatment, and III-Endodontic Treatment. Each participant marked their perceived level of stress during the performed dental treatment procedures. The scale included values of 0-6, where 0 indicates no stress, while 6 indicates high stress. RESULTS: Third- (p=0.006) and fourth-year (p=0.009) women were characterized by a higher level of perceived stress during dental procedures related to caries treatment. Caries treatment procedures were the most stressful for 18.3% of third-year students, 4.3% of fourth-year students, and 3.2% of fifth-year students. Furthermore, 63.4% of third-year students, 47.3% of fourth-year students, and 17.2% of fifth-year students indicated that they felt a high level of stress when performing endodontic procedures. CONCLUSION: Third- and fourth-year female students are characterized by a higher level of stress during caries and endodontic treatment procedures. The most stressful treatments for participants were endodontic treatment procedures.

The Effect of 4'-hydroxy-3,4,5-trimetoxystilbene, the Metabolite of Resveratrol Analogue DMU-212, on Growth, Cell Cycle and Apoptosis in DLD-1 and LOVO Colon Cancer Cell Lines.

Resveratrol is a phytoalexin that naturally occurs in grapes, blueberries, cranberries, peanuts and many other plants. Although resveratrol inhibits carcinogenesis in all three stages, its clinical application is restricted due to poor pharmacokinetics. The methylated analogues of resveratrol have been found to have higher bioavailability and cytotoxic activity than that of the prototupe compound. Among the various methoxy derivatives of resveratrol, 3,4,5,4'-tetrametoxystilbene (DMU-212) is suggested to be one of the strongest activators of cytotoxicity and apoptosis. DMU-212 has been shown to exert anti-tumor activity in DLD-1 and LOVO colon cancer cells. Since colorectal cancer is the third most common cause of cancer-related deaths worldwide, the development of new anticancer agents is nowadays of high significance. The aim of the present study was to assess the anticancer activity of 4'-hydroxy-3,4,5-trimetoxystilbene (DMU-281), the metabolite of DMU-212, in DLD-1 and LOVO cell lines. We showed for the first time the cytotoxic activity of DMU-281 triggered via cell cycle arrest at G2/M phase and apoptosis induction accompanied by the activation of caspases-9, -8, -3/7. Furthermore, DMU-281 has been found to change the expression pattern of genes and proteins related to intrinsic as well as extrinsic apoptosis. Since the activation of these pathways of apoptosis is still the most desired strategy in anticancer research, DMU-281 seems to provide a promising approach to the treatment of colon cancer.

The Reliability and Validity of the Telephone-Based and Online Polish eHealth Literacy Scale Based on Two Nationally Representative Samples.

Adequate ehealth literacy is one of the key instruments safeguarding people against unreliable health-related information obtained from the Internet. This paper presents an assessment of the reliability and the validity of a Polish version of the ehealth literacy scale (Pl-eHEALS). The assessment was carried out on the basis of two nationally representative samples of the Polish population. In the first survey of adults at least 50 years old, the technique of computer-assisted telephone interviewing (CATI) was applied. In the second survey of young adult women (18-35 years old), the technique of computer-assisted web interviewing (CAWI) was used. The reliability and the validity of the Pl-eHEALS was analyzed. There were no floor or ceiling effects revealed in either sample. The Cronbach's alpha coefficients were 0.90 and 0.88, and Guttman split-half coefficients were 0.89 and 0.81, respectively. Exploratory factors analysis revealed single factor models in both cases. The sum of squared loadings in the first survey was 6.090 and accounted for 58.72% of the variance. In the second survey, the sum was 5.927 and was responsible for 55.06% of the variance. Hypothesis testing showed that, for older adults, higher ehealth literacy was prevalent in the respondents who used the Internet more frequently. Among young adult women, higher readiness to use the Internet as a primary source of health-related information and to undertake specific internet health-related activities was associated with higher ehealth literacy. The analysis reported in this paper confirmed the reliability and the validity of the instrument. It should be stressed that, prior to this study, there was no validated Polish version of the eHEALS that could be used with Polish-speaking respondents.

Ferritin as a potential biomarker of efficacy of treatment of atrial fibrillation - preliminary report.

BACKGROUND: Complex mechanisms of responsible for originating and maintaining of atrial fibrillation (AF) are involved in pathophysiology of this arrhythmia. Inflammation substantially contribute to arrhythmic remodelling of atrial tissue.The aim of the present study is to assess an applicability of ferritin and high sensitive C-reactive protein (hs-CRP) as biomarkers of atrial fibrillation and their usefulness in evaluation of efficacy of cryoablation. MATERIALS AND METHODS: The study population consisted of 40 patients who underwent first AF cryoablation procedure. The whole follow-up time was for 6 months. The efficacy of cryoablation was defined as lack of episodes of AF longer than 30 s reported either in patient's medical documentation or present in standard or Holter ECG records. Concentrations of hs-CRP (latex method ) and ferritin (immunochemical method) were determined in standard way in hospital laboratory. RESULTS: The recurrence of atrial fibrillation during follow-up was detected in 7 of 40 patients (efficacy 82.5%). Basal concentrations of hs-CRP and ferritin were significantly higher in patients who underwent ablation during AF. Ablation resulted in an increase of either hs-CRP or ferritin concentrations. After seven days, both hs-CRP and ferritin concentrations returned to basal level. The trend toward the higher concentration of hs-CRP was observed in AF recurrence subgroup in 30th and the 90th day after the procedure. Ferritin concentrations were significantly higher in recurrence subgroup after 30 and 90 days. CONCLUSION: Our results suggest that the evaluation of ferritin serum level can be a potential tool for assessment of AF treatment efficacy.

Intraosseous Lipoma of the Mandibula: A Case Report and Review of the Literature.

Lipoma is a benign tumour originating from mature adipose tissue. It can occur in any place in the body where adipose tissue is located. Intraosseous lipoma is a very rare bone tumour. The authors present an infrequent case involving intraosseous lipoma of the mandible in a 32-year old man and provide a review of case studies documented earlier in the literature.

Maxillary fibrous dysplasia associated with McCune-Albright syndrome. A case study.

McCune Albright syndrome (MCA) is a rare complication of genetic origin. The authors present a case study of a patient with MCA diagnosed with multifocal fibrous dysplasia in his limb and craniofacial bones. The symptoms of the disease in the patient's facial and oral tissue and the treatment administered have been described.

Canine transmigration accompanying mandibular retrognathism secondary to osteitis.

Transmigration is a tooth pathology in which the migrating tooth bud passes the median plane. METHODS: This study is a presentation of the diagnostic and therapeutic outcomes in the cases of 4 stomach teeth transmigrations diagnosed in 3 patients with mandibular retrognathia which was a complication after osteitis in the postnatal period and infancy. RESULTS: Extending imaging diagnostics to include CT, most preferably CBCT, makes it possible to precisely evaluate a transmigrated canine's position and to plan a course of treatment. CONCLUSIONS: Planning of the treatment of teeth in transmigration in patients with temporomandibular ankylosis should be done by a team consisting of an orthodontist and a surgeon.

Pluripotent stem cell miRNAs and metastasis in invasive breast cancer.

BACKGROUND: The purpose of this study is to determine whether microRNA for pluripotent stem cells are also expressed in breast cancer and are associated with metastasis and outcome. METHODS: We studied global microRNA profiles during differentiation of human embryonic stem cells (n =26) and in breast cancer patients (n = 33) and human cell lines (n = 35). Using in situ hybridization, we then investigated MIR302 expression in 318 untreated breast cancer patients (test cohort, n = 22 and validation cohort, n = 296). In parallel, using next-generation sequencing data from breast cancer patients (n = 684), we assessed microRNA association with stem cell markers. All statistical tests were two-sided. RESULTS: In healthy tissues, the MIR302 (high)/MIR203 (low) asymmetry was exclusive for pluripotent stem cells. MIR302 was expressed in a small population of cancer cells within invasive ductal carcinoma, but not in normal breast (P < .001). Furthermore, MIR302 was expressed in the tumor cells together with stem cell markers, such as CD44 and BMI1. Conversely, MIR203 expression in 684 breast tumors negatively correlated with CD44 (Spearman correlation, Rho = -0.08, P = .04) and BMI1 (Rho = -0.11, P = .004), but positively correlated with differentiation marker CD24 (Rho = 0.15, P < .001). Primary tumors with lymph node metastasis had cancer cells showing scattered expression of MIR302 and widespread repression of MIR203. Finally, overall survival was statistically significantly shorter in patients with MIR302-positive cancer cells (P = .03). CONCLUSIONS: In healthy tissues the MIR302(high)/MIR203(low) asymmetry was characteristic of embryonic and induced pluripotency. In invasive ductal carcinoma, the MIR302/MIR203 asymmetry was associated with stem cell markers, metastasis, and shorter survival.

A differential microRNA profile distinguishes cholangiocarcinoma from pancreatic adenocarcinoma.

BACKGROUND: Cancers of the bile duct and the pancreas are virtually indistinguishable using conventional histopathological and clinical characteristics. We sought to use microRNA (miR) profiling to differentiate these two cancers. METHODS: RNA was harvested from the tumors of patients undergoing curative resection for cholangiocarcinoma or pancreatic adenocarcinoma and compared with adjacent normal bile duct or pancreas, respectively. There were 31 pairs of cholangiocarcinoma with matched tumor and adjacent bile duct and nine pairs of pancreatic cancer with matched tumor and adjacent uninvolved pancreas that had sufficient quantity of RNA that were included in the final analysis. Differential microRNA expression profiles were determined using the nCounter System from nanoString Technologies (Seattle, WA,USA). RESULTS: A total of 41 differentially expressed miRs were identified in cholangiocarcinoma (25 overexpressed, 16 underexpressed) and 52 differentially expressed miRs were found in pancreatic adenocarcinoma (30 overexpressed, 22 underexpressed) relative to adjacent normal tissue. Of these two profiles, 15 miRs were commonly dysregulated between tumor types. Also, eight miRs were similarly overexpressed or underexpressed in cholangiocarcinoma and pancreatic adenocarcinoma, whereas the other seven miRs had inverse expression levels. CONCLUSIONS: Cholangiocarcinoma has a distinct miR profile from pancreatic adenocarcinoma. Discrimination between these two tumor types may be possible with as few as seven miRs.

Hypoxia induces the overexpression of microRNA-21 in pancreatic cancer cells.

BACKGROUND: Pancreatic cancer cells exist in a hypoxic microenvironment containing numerous factors that impact tumor survival, proliferation, and metastasis. MicroRNAs (miRs) are differentially expressed in cancer but also altered by hypoxia. We hypothesized that hypoxia could induce expression of miR-21, an oncomir in pancreatic cancer cells. MATERIALS AND METHODS: We examined how hypoxia regulates miR-21 expression in pancreatic cancer cell lines (BxPC-3, AsPC-1) by stem-loop RT-PCR. Chromatin immunoprecipitation assays were used to study how hypoxia alters hypoxia-inducible factor (HIF)-1α binding to the hypoxia response element of miR-21. BxPC-3 and AsPC-1 cells were transfected with a constitutively stable HIF-1α subunit or vector control (pcDNA3.1) to determine the influence of miR-21 in normoxia. The effect of mature miR-21 sense and antisense oligonucleotides on proliferation and apoptosis in hypoxic and normoxic conditions was assessed via WST-1 assay and flow cytometry. RESULTS: MiR-21 levels increased in all cell lines grown in hypoxic conditions versus normoxia, whereas siRNA targeting HIF-1α reduced miR-21 expression. Hypoxic conditions resulted in direct binding of HIF-1α to the predicted binding site in miR-21. Transfection with a constitutively stable HIF-1α expression plasmid in normoxia resulted in upregulated miR-21, similar to that seen in hypoxia. Cells transfected with antisense constructs targeting miR-21 had reduced proliferation and increased apoptosis in normoxia, whereas miR-21 overexpression abrogated hypoxia-associated reductions in proliferation. CONCLUSIONS: MiR-21 is induced by hypoxia in pancreatic cancer cells via HIF-1α upregulation. MiR-21 overexpression allows cells to avoid apoptosis in a hypoxic microenvironment. Inhibition of miR-21 expression may increase cellular susceptibility to hypoxia in pancreatic cancer.

Concomitant dysregulation of microRNAs miR-151-3p and miR-126 correlates with improved survival in resected cholangiocarcinoma.

BACKGROUND: MicroRNAs (miRNAs) are small non-coding genes which become dysregulated in cancer and may predict survival. The role of miRNAs in outcomes in cholangiocarcinoma (CC) has not been reported. METHODS: RNA was extracted from 32 resected CCs along with adjacent uninvolved bile duct epithelium. A total of 43 miRNAs were quantified using NanoString™. Clinicopathologic characteristics and outcomes were captured and compared. Overall survival curves were created using the Kaplan-Meier method; factors, including miRNA expression, were compared by log-rank, chi-squared or Cox regression analyses. RESULTS: Absolute expression of each miRNA was compared with overall survival after excluding perioperative deaths (n= 3). One upregulated (miR-151-3p; P= 0.003) and one downregulated (miR-126; P= 0.023) miRNA in resected CC relative to adjacent normal bile duct epithelium correlated with survival on univariate analysis. Clinical factors and these miRNAs were compared. Dysregulated miR-151-3p and miR-126, respectively, were the only factors that correlated with improved overall survival [41.5 months vs. 12.3 months (P= 0.002) and 21.9 months vs. 15.1 months (P= 0.02), respectively]. In eight patients, both miRNAs were dysregulated. In the remainder, only one or neither showed dysregulation. Concomitant dysregulation correlated with the best overall survival (58.7 months vs. 15.1 months; P < 0.000; n= 8); clinicopathologic factors in these groups were otherwise similar. CONCLUSIONS: In resected CC, the concomitant dysregulation of both miR-151-3p and miR-126 was the factor related to the greatest improvement in overall survival. Further analysis of the targets of these miRNAs may yield potential therapeutic targets or prognostic biomarkers.

Pancreatic cancer-associated stellate cells promote differentiation of myeloid-derived suppressor cells in a STAT3-dependent manner.

Pancreatic stellate cells (PSC) are a subset of pancreatic cancer-associated fibroblasts. These cells provide prosurvival signals to tumors; however, little is known regarding their interactions with immune cells within the tumor microenvironment. We hypothesized that factors produced by human PSC could enhance myeloid-derived suppressor cell (MDSC) differentiation and function, which promotes an immunosuppressive microenvironment. Primary PSC cell lines (n = 7) were generated from human specimens and phenotypically confirmed via expression of vimentin, α-smooth muscle actin (α-SMA), and glial fibrillary acidic protein (GFAP). Luminex analysis indicated that PSC but not human fetal primary pancreatic fibroblast cells (HPF; negative controls) produced MDSC-promoting cytokines [interleukin (IL-6), VEGF, macrophage colony-stimulating factor (M-CSF) ] and chemokines (SDF-1, MCP-1). Culture of peripheral blood mononuclear cells [peripheral blood mononuclear cell (PBMC), n = 3 donors] with PSC supernatants or IL-6/granulocyte macrophage colony-stimulating factor (GM-CSF; positive control) for 7 days promoted PBMC differentiation into an MDSC (CD11b+CD33+) phenotype and a subpopulation of polymorphonuclear CD11b+CD33+CD15+ cells. The resulting CD11b+CD33+ cells functionally suppressed autologous T-lymphocyte proliferation. In contrast, supernatants from HPF did not induce an MDSC phenotype in PBMCs. Culture of normal PBMCs with PSC supernatants led to STAT3 but not STAT1 or STAT5 phosphorylation. IL-6 was an important mediator as its neutralization inhibited PSC supernatant-mediated STAT3 phosphorylation and MDSC differentiation. Finally, the FLLL32 STAT3 inhibitor abrogated PSC supernatant-mediated MDSC differentiation, PSC viability, and reduced autocrine IL-6 production indicating these processes are STAT3 dependent. These results identify a novel role for PSC in driving immune escape in pancreatic cancer and extend the evidence that STAT3 acts as a driver of stromal immunosuppression to enhance its interest as a therapeutic target.

Association of a microRNA/TP53 feedback circuitry with pathogenesis and outcome of B-cell chronic lymphocytic leukemia.

CONTEXT: Chromosomal abnormalities (namely 13q, 17p, and 11q deletions) have prognostic implications and are recurrent in chronic lymphocytic leukemia (CLL), suggesting that they are involved in a common pathogenetic pathway; however, the molecular mechanism through which chromosomal abnormalities affect the pathogenesis and outcome of CLL is unknown. OBJECTIVE: To determine whether the microRNA miR-15a/miR-16-1 cluster (located at 13q), tumor protein p53 (TP53, located at 17p), and miR-34b/miR-34c cluster (located at 11q) are linked in a molecular pathway that explains the pathogenetic and prognostic implications (indolent vs aggressive form) of recurrent 13q, 17p, and 11q deletions in CLL. DESIGN, SETTING, AND PATIENTS: CLL Research Consortium institutions provided blood samples from untreated patients (n = 206) diagnosed with B-cell CLL between January 2000 and April 2008. All samples were evaluated for the occurrence of cytogenetic abnormalities as well as the expression levels of the miR-15a/miR-16-1 cluster, miR-34b/miR-34c cluster, TP53, and zeta-chain (TCR)-associated protein kinase 70 kDa (ZAP70), a surrogate prognostic marker of CLL. The functional relationship between these genes was studied using in vitro gain- and loss-of-function experiments in cell lines and primary samples and was validated in a separate cohort of primary CLL samples. MAIN OUTCOME MEASURES: Cytogenetic abnormalities; expression levels of the miR-15a/miR-16-1 cluster, miR-34 family, TP53 gene, downstream effectors cyclin-dependent kinase inhibitor 1A (p21, Cip1) (CDKN1A) and B-cell CLL/lymphoma 2 binding component 3 (BBC3), and ZAP70 gene; genetic interactions detected by chromatin immunoprecipitation. RESULTS: In CLLs with 13q deletions the miR-15a/miR-16-1 cluster directly targeted TP53 (mean luciferase activity for miR-15a vs scrambled control, 0.68 relative light units (RLU) [95% confidence interval {CI}, 0.63-0.73]; P = .02; mean for miR-16 vs scrambled control, 0.62 RLU [95% CI, 0.59-0.65]; P = .02) and its downstream effectors. In leukemic cell lines and primary CLL cells, TP53 stimulated the transcription of miR-15/miR-16-1 as well as miR-34b/miR-34c clusters, and the miR-34b/miR-34c cluster directly targeted the ZAP70 kinase (mean luciferase activity for miR-34a vs scrambled control, 0.33 RLU [95% CI, 0.30-0.36]; P = .02; mean for miR-34b vs scrambled control, 0.31 RLU [95% CI, 0.30-0.32]; P = .01; and mean for miR-34c vs scrambled control, 0.35 RLU [95% CI, 0.33-0.37]; P = .02). CONCLUSIONS: A microRNA/TP53 feedback circuitry is associated with CLL pathogenesis and outcome. This mechanism provides a novel pathogenetic model for the association of 13q deletions with the indolent form of CLL that involves microRNAs, TP53, and ZAP70.

Single-nucleotide polymorphisms inside microRNA target sites influence tumor susceptibility.

Single-nucleotide polymorphisms (SNP) associated with polygenetic disorders, such as breast cancer (BC), can create, destroy, or modify microRNA (miRNA) binding sites; however, the extent to which SNPs interfere with miRNA gene regulation and affect cancer susceptibility remains largely unknown. We hypothesize that disruption of miRNA target binding by SNPs is a widespread mechanism relevant to cancer susceptibility. To test this, we analyzed SNPs known to be associated with BC risk, in silico and in vitro, for their ability to modify miRNA binding sites and miRNA gene regulation and referred to these as target SNPs. We identified rs1982073-TGFB1 and rs1799782-XRCC1 as target SNPs, whose alleles could modulate gene expression by differential interaction with miR-187 and miR-138, respectively. Genome-wide bioinformatics analysis predicted approximately 64% of transcribed SNPs as target SNPs that can modify (increase/decrease) the binding energy of putative miRNA::mRNA duplexes by >90%. To assess whether target SNPs are implicated in BC susceptibility, we conducted a case-control population study and observed that germline occurrence of rs799917-BRCA1 and rs334348-TGFR1 significantly varies among populations with different risks of developing BC. Luciferase activity of target SNPs, allelic variants, and protein levels in cancer cell lines with different genotypes showed differential regulation of target genes following overexpression of the two interacting miRNAs (miR-638 and miR-628-5p). Therefore, we propose that transcribed target SNPs alter miRNA gene regulation and, consequently, protein expression, contributing to the likelihood of cancer susceptibility, by a novel mechanism of subtle gene regulation.

Non-codingRNA sequence variations in human chronic lymphocytic leukemia and colorectal cancer.

Cancer is a genetic disease in which the interplay between alterations in protein-coding genes and non-coding RNAs (ncRNAs) plays a fundamental role. In recent years, the full coding component of the human genome was sequenced in various cancers, whereas such attempts related to ncRNAs are still fragmentary. We screened genomic DNAs for sequence variations in 148 microRNAs (miRNAs) and ultraconserved regions (UCRs) loci in patients with chronic lymphocytic leukemia (CLL) or colorectal cancer (CRC) by Sanger technique and further tried to elucidate the functional consequences of some of these variations. We found sequence variations in miRNAs in both sporadic and familial CLL cases, mutations of UCRs in CLLs and CRCs and, in certain instances, detected functional effects of these variations. Furthermore, by integrating our data with previously published data on miRNA sequence variations, we have created a catalog of DNA sequence variations in miRNAs/ultraconserved genes in human cancers. These findings argue that ncRNAs are targeted by both germ line and somatic mutations as well as by single-nucleotide polymorphisms with functional significance for human tumorigenesis. Sequence variations in ncRNA loci are frequent and some have functional and biological significance. Such information can be exploited to further investigate on a genome-wide scale the frequency of genetic variations in ncRNAs and their functional meaning, as well as for the development of new diagnostic and prognostic markers for leukemias and carcinomas.

MicroRNAs in solid tumors.

MicroRNAs (miRNAs or miRs) are small, noncoding RNAs (approximately 20-22 nucleotides) that have critical functions in cell proliferation, apoptosis, and differentiation. These evolutionarily conserved RNA sequences are the result of a complex sequence of processing steps, which can regulate the expression of tens, and even hundreds, of genes. Their regulatory effect is based upon the degree of complementarity between the mature miRNA and the 3' untranslated region region of the target mRNA resulting in either complete degradation or translational inhibition of the target mRNA. In vertebrates they are often tissue specific in their expression patterns and dysregulated in malignancies. Thus, miRNA profiling has been used to create signatures for many solid malignancies. These profiles have been used to not only classify tumors, but also to help predict survival and outcome. Herein, we review the role of miRNAs in the development and progression of solid tumors.