Nickel and Chromium Ion Release from Orthodontic Wires Subjected to Various Drinks and Distilled Water.

Objectives: The aim of this in vitro study was to assess the quantity of nickel and chromium ions released from orthodontic wires when subjected to various beverage solutions and distilled water. Materials and Methods: Orthodontic appliances composed of five brackets, one band and 0.016-inch stainless steel and nickel titanium wires were immersed in Coke, tea, coffee and distilled water. The samples were incubated at 37°C for 1 hour, 6 hours, 24 hours, and one week. There was a total of 120 appliances divided into 24 groups (n=5 in each group). Atomic absorption spectroscopy was used to examine the amount of released ions. Two-way and one-way ANOVA followed by Tukey test were used for statistical analysis and P<0.05 was considered significant. Results: The release of nickel ions from both wires was highest in Coke and lowest in distilled water at all time points. Coffee and tea demonstrated values in-between these two limits. Similarly, chromium ion release from both wires was highest in Coke at all time-points compared to all other solutions (P<0.05). None of the other tested drinks showed significant differences in chromium ion release compared to distilled water. Conclusion: Restricting the intake of acidic drinks, particularly carbonated beverages like Coke, plays a critical role in safeguarding orthodontic wire components. Educating patients and providing dietary guidelines are essential for maximizing treatment effectiveness. Further research is required to investigate additional factors impacting ion release and devising methods to mitigate potential harm.

Neuropeptide Y directly reduced apoptosis of granulosa cells, and the expression of NPY and its receptors in PCOS subjects.

BACKGROUND: Most women with anovulatory infertility show polycystic ovarian syndrome (PCOS), and androgen excess is known as a key factor involved in pathogenicity of PCOS. However, the mechanism of follicular developmental arrest in PCOS is not completely understood. The reproductive function of Neuropeptide Y (NPY) in the ovary during folliculogenesis was previously reported; NPY function in apoptosis and proliferation of granulosa cells (GCs) is follicular-stage dependent. The objective of this study was to investigate the role of NPY in ovarian follicular development and the pathogenesis of PCOS. METHODS: To simulate the PCOS phenotype using a rat model, 21-day old Sprague Dawley rats were implanted with dihydrotestosterone (DHT) capsule (83 µg/day) and euthanized after 28 days. mRNA and protein content of NPY and its receptors were assessed in GCs from DHT treated rats using RT-qPCR and Western blot, respectively. Proliferation and apoptosis of GCs was assessed using Ki67- and TUNEL assays. Finally, NPY levels were measured in human follicular fluid (FF) from matched PCOS and non-PCOS patients using ELISA. RESULTS: GCs from DHT treated rats (PCOS-GCs) contained significantly less NPY protein and Npy mRNA by 0.16- and 0.56-fold, respectively, and more NPY receptor type 2 and 5 protein by 2.21- and 3.17-fold, respectively, when compared to sham control. Addition of recombinant NPY to PCOS-GCs culture did not alter Ki67-positive but significantly decreased TUNEL-positive cells by 0.65-fold, but not to baseline levels. There was no significant difference in NPY levels in FF between PCOS and non-PCOS subjects. CONCLUSIONS: These results indicate that DHT modulates expression of NPY and its receptors, NPY decreases DHT-induced GCs apoptosis. That alterations in NPY's function might be involved in follicular developmental failure of PCOS.

Obesity and PCOS radically alters the snRNA composition of follicular fluid extracellular vesicles.

Introduction: The ovarian follicle consists of the oocyte, somatic cells, and follicular fluid (FF). Proper signalling between these compartments is required for optimal folliculogenesis. The association between polycystic ovarian syndrome (PCOS) and extracellular vesicular small non-coding RNAs (snRNAs) signatures in follicular fluid (FF) and how this relates to adiposity is unknown. The purpose of this study was to determine whether FF extracellular vesicle (FFEV)-derived snRNAs are differentially expressed (DE) between PCOS and non-PCOS subjects; and if these differences are vesicle-specific and/or adiposity-dependent. Methods: FF and granulosa cells (GC) were collected from 35 patients matched by demographic and stimulation parameters. FFEVs were isolated and snRNA libraries were constructed, sequenced, and analyzed. Results: miRNAs were the most abundant biotype present, with specific enrichment in exosomes (EX), whereas in GCs long non-coding RNAs were the most abundant biotype. In obese PCOS vs. lean PCOS, pathway analysis revealed target genes involved in cell survival and apoptosis, leukocyte differentiation and migration, JAK/STAT, and MAPK signalling. In obese PCOS FFEVs were selectively enriched (FFEVs vs. GCs) for miRNAs targeting p53 signalling, cell survival and apoptosis, FOXO, Hippo, TNF, and MAPK signalling. Discussion: We provide comprehensive profiling of snRNAs in FFEVs and GCs of PCOS and non-PCOS patients, highlighting the effect of adiposity on these findings. We hypothesize that the selective packaging and release of miRNAs specifically targeting anti-apoptotic genes into the FF may be an attempt by the follicle to reduce the apoptotic pressure of the GCs and stave off premature apoptosis of the follicle observed in PCOS.

Androgen-induced exosomal miR-379-5p release determines granulosa cell fate: cellular mechanism involved in polycystic ovaries.

Polycystic ovarian syndrome (PCOS) is a complex multi-factorial syndrome associated with androgen excess and anovulatory infertility. In the current study, we investigated the role of dihydrotestosterone-induced exosomal miR-379-5p release in determining the destiny of the developing follicles. Our hypothesis was that androgen regulates granulosa cell miR-379-5p content by facilitating its exosomal release in a follicular-stage dependent manner, a process which determines granulosa cell fate. Compared to human non-PCOS subjects, individuals with PCOS exhibit higher follicular fluid free testosterone levels, lower exosomal miR-379-5p content and granulosa cell proliferation. Androgenized rats exhibited lower granulosa cell miR-379-5p but higher phosphoinositide-dependent kinase-1 (PDK1; a miR-379-5p target) content and proliferation. Androgen reduced granulosa cell miR-379-5p content by increasing its exosomal release in preantral follicles, but not in antral follicles in vitro. Studies with an exosomal release inhibitor confirmed that androgen-induced exosomal miR-379-5p release decreased granulosa cell miR-379-5p content and proliferation. Ovarian overexpression of miR-379-5p suppressed granulosa cell proliferation, and basal and androgen-induced preantral follicle growth in vivo. These findings suggest that increased exosomal miR-379-5p release in granulosa cells is a proliferative response to androgenic stimulation specific for the preantral stage of follicle development and that dysregulation of this response at the antral stage is associated with follicular growth arrest, as observed in human PCOS.

Granulosa cell-derived miR-379-5p regulates macrophage polarization in polycystic ovarian syndrome.

Polycystic ovarian syndrome (PCOS) is associated with hyperandrogenemia and ovarian antral follicle growth arrest. We have previously demonstrated that androgen-induced exosomal release of miR-379-5p (miR379) from preantral follicle granulosa cells increases the proliferation of target cells via phosphoinositide-dependent kinase 1 (PDK1) upregulation. Androgen also increases inflammatory M1 macrophage abundance, but reduces anti-inflammatory M2 polarization in rat antral and preovulatory follicles. However, the role of small extracellular vesicles (sEVs; also known as exosomes) secretion in determining the cellular content and function of miRNAs in exosome-receiving cells is largely unknown. Our objectives were to determine: 1) the regulatory role of granulosa cells (GC)-derived exosomal miR379 on macrophage polarization and ovarian inflammation; 2) whether miR379-induced M1 polarization regulates GC proliferation; and 3) if this regulated process is follicular stage-specific. Compared with non-PCOS subjects, PCOS subjects had a higher M1/M2 ratio, supporting the concept that PCOS is an inflammatory condition. Ovarian overexpression of miR379 increased the number of M1 macrophages and the M1/M2 ratio in preantral follicles specifically. Transfection of macrophages with a miR379 mimic reduced the cellular content of PDK1 and induced M0→M1 polarization; whereas its inhibitor polarized M0→M2. Conditioned media from macrophages transfected with miR379 mimic and follicular fluid from PCOS subjects had higher galectin-3 content, a pro-inflammatory cytokine which specifically suppresses human antral follicle GC proliferation. These results indicate that miR379 inhibits M2 macrophage polarization, a condition which suppresses GC proliferation in a follicle stage-dependent manner, as exhibited in PCOS.

Staining-free, Automated Sperm Analysis for In Vitro Fertilization Lab Use.

PURPOSE: Computer-aided sperm analysis is typically used in andrology labs, not in in vitro fertilization labs, which requires staining for sperm morphology measurement. In in vitro fertilization labs, sperm analysis still relies on manual observation and suffers from subjectivity and inconsistency. We developed a system for automated measurement of sperm concentration, motility, and morphology without the need for sperm staining. The reproducibility and reliability of the system were evaluated. MATERIALS AND METHODS: Thirty-five fresh semen and 25 washed samples were obtained from male partners attending for fertility investigations. Sperm concentration, motility, and morphology were automatically measured simultaneously, leveraging robust sperm tracking for concentration and motility measurement and low contrast image segmentation for morphology measurement of live sperm. Reproducibility of sperm measurements was evaluated by intraclass correlation coefficients. Reliability of sperm measurement was evaluated by Passing and Bablok regression analysis and Bland-Altman analysis. RESULTS: Automated measurement of concentration, motility, and morphology had intraclass correlation coefficients higher than 0.97. The regression and Bland-Altman analysis indicated that automated measurement and off-line manual benchmarking with zoomed-in images were interchangeable. Further analysis on semen and washed samples and the measurement on progressive and nonprogressive motility also showed high reproducibility and reliability. CONCLUSIONS: Automated sperm analysis revealed high reproducibility and reliability. The system is designed for routine use in in vitro fertilization labs to perform quantitative sperm analysis on live samples.

Cannabis significantly alters DNA methylation of the human ovarian follicle in a concentration-dependent manner.

Cannabis is increasingly consumed by women of childbearing age, and the reproductive and epigenetic effects are unknown. The purpose of this study was to evaluate the potential epigenetic implications of cannabis use on the female ovarian follicle. Whole-genome methylation was assessed in granulosa cells from 14 matched case-control patients. Exposure status was determined by liquid chromatography-mass spectrometry (LC-MS/MS) measurements of five cannabis-derived phytocannabinoids in follicular fluid. DNA methylation was measured using the Illumina TruSeq Methyl Capture EPIC kit. Differential methylation, pathway analysis and correlation analysis were performed. We identified 3679 differentially methylated sites, with two-thirds affecting coding genes. A hotspot region on chromosome 9 was associated with two genomic features, a zinc-finger protein (ZFP37) and a long non-coding RNA (FAM225B). There were 2214 differentially methylated genomic features, 19 of which have been previously implicated in cannabis-related epigenetic modifications in other organ systems. Pathway analysis revealed enrichment in G protein-coupled receptor signaling, cellular transport, immune response and proliferation. Applying strict criteria, we identified 71 differentially methylated regions, none of which were previously annotated in this context. Finally, correlation analysis revealed 16 unique genomic features affected by cannabis use in a concentration-dependent manner. Of these, the histone methyltransferases SMYD3 and ZFP37 were hypomethylated, possibly implicating histone modifications as well. Herein, we provide the first DNA methylation profile of human granulosa cells exposed to cannabis. With cannabis increasingly legalized worldwide, further investigation into the heritability and functional consequences of these effects is critical for clinical consultation and for legalization guidelines.

Cannabis alters epigenetic integrity and endocannabinoid signalling in the human follicular niche.

STUDY QUESTION: Do phytocannabinoids (PCs) affect follicular endocannabinoid signalling and the epigenome in the surrounding granulosa cells (GCs)? SUMMARY ANSWER: Exposure to PCs increases the expression of endocannabinoid receptors and reduces DNA methylation enzyme expression and global DNA methylation in naïve GCs. WHAT IS KNOWN ALREADY: Cannabis plant derivatives, known as PCs, are used for medicinal and recreational purposes. The main PC, tetrahydrocannabinol (THC), is the third most commonly used substance by women of childbearing age, hence knowledge of the effect it has on reproduction is of utmost importance. THC exerts its effects via receptors of the endocannabinoid system (ECS) and can interfere with folliculogenesis, oocyte development and ovulation. Endocannabinoids have been measured in follicular fluid (FF) obtained during oocyte retrieval and are implicated in controlling folliculogenesis. It has been established that in the placenta, PCs disrupt endocannabinoid homeostasis via impairment of the synthetic and degrading enzymes, leading to a net increase of endocannabinoid levels. Finally, previous studies have shown that THC alters methylation and histone modifications in sperm, brain and blood cells. STUDY DESIGN, SIZE, DURATION: This study included an in vivo cohort assessment of cannabis exposure and its effects on the follicle and in vitro assays conducted to validate the in vivo findings and to explore possible mechanisms of action. PARTICIPANTS/MATERIALS, SETTING, METHODS: A total of 318 FF samples, from 261 patients undergoing IVF treatment at a private fertility clinic who consented for biobanking biological waste material between January 2018 and July 2019, were included in this study. Concentrations of PCs and endocannabinoids were assessed in FF by liquid chromatography-mass spectrometry (LC-MS/MS). Exposure to PCs was determined based on these measured levels. Levels of both endocannabinoid receptors (CB1R, CB2R) and the de novo DNA methylating enzyme, DNMT3b, in GCs were assessed by flow cytometry both in vitro and in vivo and global DNA methylation was assessed in vitro by ELISA. In vivo effects were assessed by comparing samples positive for at least one PC, with samples negative for all measured PCs. In vitro effects were determined in naive GCs, obtained concurrently with FF samples that had tested negative for all PCs. These GCs were treated with different combinations of the main three PCs. MAIN RESULTS AND THE ROLE OF CHANCE: Overall, 17 patients (6.4%) were positive for cannabis consumption. Furthermore, the prevalence of cannabis positivity in the FF increased from 4% of the tested samples that were collected prior to national legalisation in October 2018 to 12% of those collected following legalisation. Of note, 59% of patients who tested positive for PCs (10 of 17) reported previous or ongoing exposure to cannabis upon their initial intake. Endocannabinoid levels were not affected by the presence of PCs. CB2R was more prevalent than CB1R in GCs and its expression increased following acute and chronic in vitro exposure to PCs. The expression of DNMT3b and global methylation decreased following exposure, suggesting that cannabis may affect the epigenome in the follicular niche. The acute changes were sustained throughout chronic treatment. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Our study is limited by lack of details regarding mode, frequency and timing of PC consumption. Moreover, we were not able to adequately assess the effect of PCs on immediate or long-term clinical outcomes, due to the small sample size and the lack of follow up. Future, large-scale studies should focus on assess the clinical implications of cannabis exposure, validate our findings, and determine to what extent cannabis affects the epigenome ovarian follicle and the developing oocyte. WIDER IMPLICATIONS OF THE FINDINGS: To our knowledge, this is the first study measuring PCs in FF by LC-MS/MS. We show that consuming cannabis alters the ECS in the developing follicle, and directly affects DNMT expression and global DNA methylation levels. Cannabis legalisation and use is increasing worldwide, therefore further understanding its role in female fertility and folliculogenesis is critical. STUDY FUNDING/COMPETING INTEREST(S): All funding was provided by CReATe Fertility Centre through the reinvestment of clinical earnings. The authors declare no competing interests.

Automated motility and morphology measurement of live spermatozoa.

BACKGROUND: Automated sperm analysis has wide applications in infertility diagnosis. Existing systems are not able to measure sperm count and both motility and morphology of individual live spermatozoa. Morphology measurement requires invasive staining, making the spermatozoa after morphology measurement not applicable to infertility treatment. OBJECTIVE: To evaluate the reproducibility and reliability of automated measurement of individual live sperm's motility and morphology. MATERIALS AND METHODS: Fresh semen samples were obtained from twenty male partners attending for fertility investigations. The system firstly measured motility for all the spermatozoa within the field of view under a low magnification (20×), then a spermatozoa of interest is selected by the user and automatically relocated by the system after switching to a high magnification (100×) for morphology measurement. Reproducibility of sperm measurements was evaluated by intraclass correlation coefficients on consecutive measurement. Reliability of motility and morphology measurement was evaluated by tracking error rate and limits of agreement, respectively, with manual measurement as benchmark. RESULTS: Measurement of all motility and morphology parameters had intraclass correlation coefficients higher than 0.94. Sperm motility measurement had a tracking error rate of 2.1%. Limit of agreement analysis indicated that automated measurement and manual measurement of sperm morphology were interchangeable. Automated measurement of all morphology parameters was not statistically different from manual measurement, as confirmed by the paired sample t test. DISCUSSION: Automated motility and morphology measurement of single sperm revealed high reproducibility and reliability. The system also achieved a high efficiency for motility and morphology measurement. In addition to the intracytoplasmic sperm injection (ICSI) samples with polyvinylpyrrolidone (PVP), the developed sperm measurement technique is also effective for analyzing semen and washed samples. The system provides a valuable tool for quantitative measurement and selection of single spermatozoa for ICSI. It can also be used for sperm motility and morphology analysis in andrology laboratories.

Temporal Stability and Prognostic Biomarker Potential of the Prostate Cancer Urine miRNA Transcriptome.

BACKGROUND: The development of noninvasive tests for the early detection of aggressive prostate tumors is a major unmet clinical need. miRNAs are promising noninvasive biomarkers: they play essential roles in tumorigenesis, are stable under diverse analytical conditions, and can be detected in body fluids. METHODS: We measured the longitudinal stability of 673 miRNAs by collecting serial urine samples from 10 patients with localized prostate cancer. We then measured temporally stable miRNAs in an independent training cohort (n = 99) and created a biomarker predictive of Gleason grade using machine-learning techniques. Finally, we validated this biomarker in an independent validation cohort (n = 40). RESULTS: We found that each individual has a specific urine miRNA fingerprint. These fingerprints are temporally stable and associated with specific biological functions. We identified seven miRNAs that were stable over time within individual patients and integrated them with machine-learning techniques to create a novel biomarker for prostate cancer that overcomes interindividual variability. Our urine biomarker robustly identified high-risk patients and achieved similar accuracy as tissue-based prognostic markers (area under the receiver operating characteristic = 0.72, 95% confidence interval = 0.69 to 0.76 in the training cohort, and area under the receiver operating characteristic curve = 0.74, 95% confidence interval = 0.55 to 0.92 in the validation cohort). CONCLUSIONS: These data highlight the importance of quantifying intra- and intertumoral heterogeneity in biomarker development. This noninvasive biomarker may usefully supplement invasive or expensive radiologic- and tissue-based assays.

Release of nickel and chromium ions from orthodontic wires following the use of teeth whitening mouthwashes.

BACKGROUND: Corrosion resistance is an important requirement for orthodontic appliances. Nickel and chromium may be released from orthodontic wires and can cause allergic reactions and cytotoxicity when patients use various mouthwashes to whiten their teeth. Our study aimed to assess the release of nickel and chromium ions from nickel titanium (NiTi) and stainless steel (SS) orthodontic wires following the use of four common mouthwashes available on the market. METHODS: This in vitro, experimental study was conducted on 120 orthodontic appliances for one maxillary quadrant including five brackets, one band and half of the required length of SS, and NiTi wires. The samples were immersed in Oral B, Oral B 3D White Luxe, Listerine, and Listerine Advance White for 1, 6, 24, and 168 h. The samples immersed in distilled water served as the control group. Atomic absorption spectroscopy served to quantify the amount of released ions. RESULTS: Nickel ions were released from both wires at all time-points; the highest amount was in Listerine and the lowest in Oral B mouthwashes. The remaining two solutions were in-between this range. The process of release of chromium from the SS wire was the same as that of nickel. However, the release trend in NiTi wires was not uniform. CONCLUSIONS: Listerine caused the highest release of ions. Listerine Advance White, Oral B 3D White Luxe, and distilled water were the same in terms of ion release. Oral B showed the lowest amount of ion release.

Targeting of CCBE1 by miR-330-3p in human breast cancer promotes metastasis.

BACKGROUND: MicroRNAs (miRs) are involved in the regulation of many processes that contribute to malignancy, including cell proliferation, radiation resistance, invasion and metastasis. The role of miR-330-3p, an miR upregulated in breast cancer, remains unclear. METHODS: We examine the association of miR-330-3p with distant relapse-free survival in the Oxford cohort of breast cancer patients. We also study miR-330-3p function using in vitro invasion and ex ovo metastasis assays. Using in vitro luciferase assays, we validate a novel target gene for miR-330-3p, Collagen And Calcium Binding EGF Domains 1 (CCBE1). We assess functional consequences of CCBE1 loss by using siRNA-mediated knockdown followed by in vitro invasion assays. Lastly, we examine the expression profile of CCBE1 in breast carcinomas in the Curtis and TCGA Breast Cancer data sets using Oncomine Platform as well as distant relapse-free and overall survival of patients in the Helsinki University breast cancer data set according to CCBE1 expression status. RESULTS: miR-330-3p is enriched in breast cancer, and higher levels of miR-330-3p expression are associated with lower distant relapse-free survival in a cohort of breast cancer patients. Consistent with these observations, overexpression of miR-330-3p in breast cancer cell lines results in greater invasiveness in vitro, and miR-330-3p-overexpressing cells also metastasise more aggressively ex ovo. We identify CCBE1 as a direct target of miR-330-3p, and show that knockdown of CCBE1 results in a greater invasive capacity. Accordingly, in breast cancer patients CCBE1 is frequently downregulated, and its loss is associated with reduced distant relapse-free and overall survival. CONCLUSIONS: We show for the first time that miR-330-3p targets CCBE1 to promote invasion and metastasis. miR-330-3p and CCBE1 may represent promising biomarkers in breast cancer.

Long non-coding RNA urothelial carcinoma associated 1 (UCA1) mediates radiation response in prostate cancer.

Radioresistance remains a significant obstacle in the treatment of Prostate Cancer (PCa). To simulate the clinical scenario of irradiation resistance (IRR), we created DU145-IRR PCa cell lines by treatment with 2 Gy daily IR for 59 fractions. DU145-IRR cells acquired an aggressive phenotype as evidenced by increased clonogenic survival, tumorigenic potential and invasiveness. We performed transcriptome profiling to discover dysregulated genes in DU145-IRR cells and identified the long non-coding RNA (lncRNA), Urothelial carcinoma-associated 1 (UCA1). We first investigated the role of UCA1 in radiation response and found that UCA1 abundance was significantly higher in DU145-IRR cells compared to control cells. UCA1 siRNA-knockdown reversed the aggressive phenotype and significantly increased sensitivity to IR. UCA1 depletion inhibited growth, induced cell cycle arrest at the G2/M transition and decreased activation of the pro-survival Akt pathway. We then studied the clinical significance of UCA1 expression in two independent cohorts of PCa patients: MSKCC (130 patients) and CPC-GENE (209 patients). UCA1 over-expression was associated with decreased 5-year disease-free survival in MSKCC patients (HR = 2.9; p = 0.007) and a trend toward lower biochemical recurrence-free survival in CPC-GENE patients (HR = 2.7; p = 0.05). We showed for the first time that UCA1 depletion induces radiosensitivity, decreases proliferative capacity and disrupts cell cycle progression, which may occur through altered Akt signaling and induced cell cycle arrest at the G2/M transition. Our results indicate that UCA1 might have prognostic value in PCa and be a potential therapeutic target.

An update on clinical applications of magnetic nanoparticles for increasing the resolution of magnetic resonance imaging.

Today, technologies based on magnetic nanoparticles (MNPs) are regularly applied to biological systems with diagnostic or therapeutic aims. Nanoparticles made of the elements iron (Fe), gadolinium (Gd) or manganese (Mn) are generally used in many diagnostic applications performed under magnetic resonance imaging (MRI). Similar to molecular-based contrast agents, nanoparticles can be used to increase the resolution of imaging while offering well biocompatibility, poisonousness and biodistribution. Application of MNPs enhanced MRI sensitivity due to the accumulation of iron in the liver caused by discriminating action of the hepatobiliary system. The aim of this study is about the use, properties and advantages of MNPs in MRI.

Preparation and in vitro evaluation of Methotrexate-loaded magnetic nanoparticles modified with biocompatible copolymers.

Superparamagnetic iron oxide nanoparticles (SPION) are attractive materials that have been widely used in medicine for drug delivery, diagnostic imaging and therapeutic applications. In our study, SPION and the anticancer drug, Methotrexate, were encapsulated into polycaprolactone-polyethylene glycol (PCL-PEG) nanoparticles for local treatment. The magnetic properties conferred by SPION could help to maintain the nanoparticles in the joint with an external magnet. The drug encapsulation efficiency achieved for Fe3O4 magnetic nanoparticles modified with PCL-PEG copolymer was 92.36%. There is potential for use of these nanoparticles for biomedical application.

miR-620 promotes tumor radioresistance by targeting 15-hydroxyprostaglandin dehydrogenase (HPGD).

MicroRNA contribute to tumor radiation resistance, which is an important clinical problem, and thus we are interested in identifying and characterizing their function. We demonstrate that miR-620 contributes to radiation resistance in cancer cells by increasing proliferation, and decreasing the G2/M block. We identify the hydroxyprostaglandin dehydrogenase 15-(nicotinamide adenine dinucleotide) (HPGD/15-PGDH) tumor suppressor gene as a direct miR-620 target, which results in increased prostaglandin E2 (PGE2) levels. Furthermore, we show that siRNA targeting of HPGD or administration of exogenous PGE2 recapitulates radioresistance. Targeting of the EP2 receptor that responds to PGE2 using pharmacological or genetic approaches, abrogates radioresistance. Tumor xenograft experiments confirm that miR-620 increases proliferation and tumor radioresistance in vivo. Regulation of PGE2 levels via targeting of HPGD by miR-620 is an innovative manner by which a microRNA can induce radiation resistance.

miRNA-95 mediates radioresistance in tumors by targeting the sphingolipid phosphatase SGPP1.

Radiation resistance poses a major clinical challenge in cancer treatment, but little is known about how microRNA (miR) may regulate this phenomenon. In this study, we used next-generation sequencing to perform an unbiased comparison of miR expression in PC3 prostate cancer cells rendered resistant to fractionated radiation treatment. One miR candidate found to be upregulated by ionizing radiation was miR-95, the enforced expression of which promoted radiation resistance in a variety of cancer cells. miR-95 overexpression recapitulated an aggressive phenotype including increased cellular proliferation, deregulated G2-M checkpoint following ionizing radiation, and increased invasive potential. Using combined in silico prediction and microarray expression analyses, we identified and validated the sphingolipid phosphatase SGPP1, an antagonist of sphingosine-1-phosphate signaling, as a target of miR-95 that promotes radiation resistance. Consistent with this finding, cell treatment with FTY720, a clinically approved small molecule inhibitor of S1P signaling, sensitized miR-95 overexpressing cells to radiation treatment. In vivo assays extended the significance of these results, showing that miR-95 overexpression increased tumor growth and resistance to radiation treatment in tumor xenografts. Furthermore, reduced tumor necrosis and increased cellular proliferation were seen after radiation treatment of miR-95 overexpressing tumors compared with control tumors. Finally, miR-95 expression was increased in human prostate and breast cancer specimens compared with normal tissue. Together, our work reveals miR-95 expression as a critical determinant of radiation resistance in cancer cells.

Impact of methylenetetrahydrofolate reductase C677T polymorphism on the risk of gastric cancer and its interaction with Helicobacter pylori infection.

BACKGROUND: Attempts for early detection of gastric cancer have recently focused on host's genetic susceptibility factors and gene-environment interactions. We have, herein, studied the association of MTHFR C677T single nucleotide polymorphism (SNP) and its interaction with Helicobacter pylori infection, smoking, age and gender on the risk of gastric cancer among an Iranian population. METHODS: Gastric cancer patients (n = 450) and cancer-free controls (n = 780) were studied for serum H. pylori-specific IgG antibodies by ELISA and MTHFR C677T polymorphism (SNP) by PCR-RFLP. Demographic and life style data were collected through patient interviews. Unconditional logistic regression model estimated odds ratio (OR) and the corresponding 95% confidence intervals (CI). RESULTS: The interactions of MTHFR genotype with H. pylori infection (P = 0.03), age (P = 0.049) and gender (P = 0.007) were statistically significant. Accordingly, MTHFR C677T carriers who were also positive for H. pylori infection exhibited 80% (OR = 1.8, 95% CI = 1.0-2.9) significant excess risk of non-cardia gastric cancer. Furthermore, subjects over the age of 50 or female subjects carrying MTHFR C677T SNP showed 40 (OR = 1.4, 95% CI = 1.0-2.0) and 100 (OR = 2.0, 95% CI = 1.2-3.2) percent increased risk of gastric cancer, respectively. CONCLUSION: MTHFR C677T SNP seems to increase the risk of gastric cancer and the effect is significantly inflated by interactions with H. pylori infection, age and gender.