DEAH box RNA helicase DHX38 associates with satellite I noncoding RNA involved in chromosome segregation

Noncoding (nc) RNA called satellite I is transcribed from the human centromere region. Depletion of this ncRNA results in abnormal nuclear morphology because of defects in chromosome segregation. Some protein factors interact with this ncRNA and function as a component of a nc ribonucleoprotein (RNP) complex in mitotic regulation. Here, we found that DHX38, a pre‐mRNA splicing‐related DEAH box RNA helicase, interacts with satellite I ncRNA. Depletion of DHX38 resulted in defective chromosome segregation similar to knockdown of satellite I ncRNA. Interaction between DHX38 and ncRNA was interphase‐specific, but DHX38 depletion affected the function of Aurora B, which associated with satellite I ncRNA at mitotic phase. Based on these findings, we suggest that DHX38 has a role in mitotic regulation as a component of the satellite I ncRNP complex at interphase.     

端粒酶活性检测在妇科肿瘤早期诊断中的应用

目的　观察端粒酶活性在妇科肿瘤中的阳性率 ,探讨妇科肿瘤发生过程中端粒酶所起的作用及其在妇科肿瘤早期诊断及预后中的诊断价值。方法　用以PCR为基础的端粒重复序列扩增 (TRAP)法测定 83例妇科肿瘤标本及正常对照标本中的端粒酶活性　结果　在 6 2正常对照标本中发现 5例有端粒酶的活性表达 (8.1% ) ,在 83例子宫颈癌、卵巢癌、子宫内膜癌中端粒酶阳性率为 94 % ,和正常对照组比较 ,差异显著 (P <0 .0 0 1)。结论　端粒酶活化是妇科肿瘤中的普遍现象 ,检测端粒酶活性对早期诊断妇科肿瘤有一定意义。     

Long noncoding RNA linc-UBC1 is negative prognostic factor and exhibits tumor pro-oncogenic activity in gastric cancer

Despite the advances in the management of gastric cancer, the prognosis of advanced gastric cancer remains relatively poor. Thus, it is of urgent need to identify novel prognostic markers and therapeutic targets of gastric cancer. A growing volume of literature has indicated that lncRNAs are differentially expressed in a diverse array of cancer and play an important role in the development of cancer. Linc-UBC1, a recently identified long noncoding RNA, was initially found to be upregulated in bladder cancer. However, the role of linc-UBC1 in gastric cancer remains to be elusive. In this study, we found that linc-UBC1 was significantly upregulated in gastric cancer tissues compared to adjacent normal tissues. Furthermore, high linc-UBC1 expression was associated with lymph-node metastasis, tumor size, TNM stage and poorer prognosis. Inhibition of linc-UBC1 suppressed the proliferation, motility and invasion of gastric cancer cells. Our study suggests that linc-UBC1 may represent a novel diagnostic, prognostic biomarker and a potential therapeutic target of gastric cancer.     

Non-radioactive measurement of telomerase activity in human bladder cancer,bladder washings,and in urine

Early diagnosis is still the most important prerequisite for successful cancer treatment and this holds true for bladder cancer. Urine cytology is commonly used as a non-invasive screening procedure for the detection of bladder carcinoma, but this method is labour-intensive and often generates false-negative results. The ribonucleoprotein telomerase appears to be a promising new cancer marker, since its activity has been reported to correlate with indefinite growth. The aim of this study was to investigate whether telomerase activity can be detected in bladder cancer and in corresponding bladder washings. For this purpose, a sensitive non-radioactive TRAP (telomeric repeat amplification protocol) detection system was developed. With this technique, telomerase activity was found in 95 per cent of the carcinomas (n=20), in 70 per cent of the corresponding bladder washings, but in none of the urine samples obtained from patients with bladder carcinoma. No telomerase activity was detectable in normal urothelium or in samples from dysplastic urothelium. The data obtained from bladder washings show that superficial carcinoma cells released into the bladder still harbour telomerase activity. The absence of telomerase activity in voided urine is thus most likely due to degradation or inactivation under these conditions. The high rate of telomerase activity in bladder carcinoma indicates that the activation of telomerase is a common step in the tumourigenesis of bladder cancer. © 1998 John Wiley & Sons, Ltd.     

The noncoding RNA AK127244 in 2p16.3 locus: A new susceptibility region for neuropsychiatric disorders

The presence of redundant copy number variants (CNVs) in groups of patients with neurological diseases suggests that these variants could have pathogenic effect. We have collected array comparative genomic hybridization (CGH) data of about 2,500 patients affected by neurocognitive disorders and we observed that CNVs in 2p16.3 locus were as frequent as those in 15q11.2, being both the most frequent unbalances in our cohort of patients. Focusing to 2p16.3 region, unbalances involving NRXN1 coding region have been already associated with neuropsychiatric disorders, although with incomplete penetrance, but little is known about CNVs located proximal to the gene, in the long noncoding RNA AK127244. We found that, in our cohort of patients with neuropsychiatric disorders, the frequency of CNVs involving AK127244 was comparable to that of NRXN1 gene. Patients carrying 2p16.3 unbalances shared some common clinical characteristics regardless NRXN1 and AK127244 CNVs localization, suggesting that the AK127244 long noncoding RNA could be involved in neurocognitive disease with the same effect of NRXN1 unbalances. AK127244 as well as NRXN1 unbalances seem to have a particular influence on language development, behavior or mood, according with the topographic correlation between NRXN1 expression and prefrontal cortex functions.     

Small interfering RNA target for long noncoding RNA PCGEM1 increases the sensitivity of LNCaP cells to baicalein

The objective of this study is to investigate the inhibitory effect and mechanism of long noncoding RNA PCGEM1 siRNA combined with baicalein on prostate cancer LNCaP cells. LNCaP cells transfected with small hairpin RNA lentiviral vector targeting PCGEM1 were constructed and their expression in LNCaP cells was absent. The stable cell line of LNCaP cells infected with LV3-shRNA-PCGEM1 was successfully constructed. In addition, LV3-shRNA-PCGEM1 was able to increase the baicalein-induced inhibitory effects on LNCaP cells, and the susceptibility was 2.3 fold higher than that of baicalein alone. LV3-shRNA-PCGEM1 combined with baicalein also inhibited the colony formation, increased G2 and S phase cells, inhibited the expression of PCGEM1, and induced autophagy of LNCaP cells. In summary, LV3-shRNA-PCGEM1 may improve the sensitivity of LNCaP cells to baicalein, and the molecular mechanism may be associated with the decrease of PCGEM1 expression and the induction of autophagy. Our findings provided an experimental basis for the combined treatment of Chinese traditional and Western medicine on prostate cancer in a clinical setting.     

Association of long non-coding RNA HOTAIR and MALAT1 variants with cervical cancer risk in Han Chinese women

Long noncoding RNA (lncRNA) HOTAIR and MALAT1 are implicated in the development of multiple cancers. Genetic variants within HOTAIR and MALAT1 may affect the gene expression, thereby modifying genetic susceptibility to cervical cancer. A case-control study was designed, including 1 486 cervical cancer patients and 1 536 healthy controls. Based on RegulomeDB database, 11 SNPs were selected and genotyped by using Sequenom's Mass ARRAY. Univariate and multivariate logistic regression models were used to calculate the odds ratio (OR) and 95% confidence interval (CI). We found that the A allele of rs35643724 in HOTAIR was associated with increased risk of cervical cancer, while the C allele of rs1787666 in MALAT1 was associated with decreased risk. Compared to individuals with 0–1 unfavorable allele, those with 3–4 unfavorable alleles showed 18% increased odds of having cervical cancer. Our findings suggest that HOTAIR rs35643724 and MALAT1 rs1787666 might represent potential biomarkers for cervical cancer susceptibility.     

Similar roles for yeast Dbp2 and Arabidopsis RH20 DEAD-box RNA helicases to Ded1 helicase in tombusvirus plus-strand synthesis

Recruited host factors aid replication of plus-strand RNA viruses. In this paper, we show that Dbp2 DEAD-box helicase of yeast, which is a homolog of human p68 DEAD-box helicase, directly affects replication of Tomato bushy stunt virus (TBSV). We demonstrate that Dbp2 binds to the 3′-end of the viral minus-stranded RNA and enhances plus-strand synthesis by the viral replicase in a yeast-based cell-free TBSV replication assay. In vitro data with wt and an ATPase-deficient Dbp2 mutant indicate that Dbp2 unwinds local secondary structures at the 3′-end of the TBSV (−)RNA. We also show that Dbp2 complements the replication deficiency of TBSV in yeast containing reduced amount of Ded1 DEAD-box helicase, another host factor involved in TBSV replication, suggesting that Dbp2 and Ded1 helicases play redundant roles in TBSV replication. We also show that the orthologous AtRH20 DEAD-box helicase from Arabidopsis can increase tombusvirus replication in vitro and in yeast.     

Solar ultraviolet-induced DNA damage response: Melanocytes story in transformation to environmental melanomagenesis

Exposure to sunlight is both beneficial, as it heats the planet to a comfortable temperature, and potentially harmful, since sunlight contains ultraviolet radiation (UVR), which is deemed detrimental for living organisms. Earth's ozone layer plays a vital role in blocking most of the extremely dangerous UVC; however, low frequency/energy UVR (i.e., UVB and UVA) seeps through in minute amount and reaches the Earth's surface. Both UVB and UVA are physiologically responsible for a plethora of skin ailments, including skin cancers. The UVR is readily absorbed by the genomic DNA of skin cells, causing DNA bond distortion and UV-induced DNA damage. As a defense mechanism, the DNA damage response (DDR) signaling in skin cells activates nucleotide excision repair (NER), which is responsible for the removal of UVR-induced DNA photolesions and helps maintain the genomic integrity of the cells. Failure of proper NER function leads to mutagenesis and development of skin cancers. One of the deadliest form of skin cancers is melanoma which originates upon the genetic transformation of melanocytes, melanin producing skin cells. NER is a well-studied DNA repair system in the whole skin, as a tissue, but not much is known about it in melanocytes. Therefore, this review encapsulates NER in melanocytes, with a specific focus on its functional regulators and their cross talks due to skin heterogeneity and divulging the potential knowledge gap in the field.     

Enhanced sensitivity to DNA damage induced by cooking oil fumes in human OGG1 deficient cells

Cooking oil fumes (COFs) have been implicated as an important nonsmoking risk factor of lung cancer in Chinese women. However, the molecular mechanism of COFs-induced carcinogenicity remains unknown. To understand the molecular basis underlying COFs-induced cytotoxicity and genotoxicity as well as the roles of hOGG1 in the repair of COFs-induced DNA damage, a human lung cancer cell line with hOGG1 deficiency, A549-R was established by using a ribozyme gene targeting technique that specifically knockdowned hOGG1 in A549 lung adenocarcinoma cells. MTT and comet assays were employed to examine cell viability and DNA damage/repair, respectively, in A549-R and A549 cell lines treated with COF condensate (COFC). RT-PCR and Western blot results showed that the expression of hOGG1 in A549-R cell line was significantly decreased compared with that in A549 cell line. The concentration of COFC that inhibited cell growth by 50% (the IC50) in the A549-R cell line was much lower than that in the A549 cell line, and more COFC-induced DNA damage was detected in the A549-R cell line. The time course study of DNA repair demonstrated delayed repair kinetics in the A549-R cell line, suggesting a decreased cellular damage repair capacity. Our results showed that hOGG1 deficiency enhanced cellular sensitivity to DNA damage caused by COFC. The results further indicate that hOGG1 plays an important role in repairing COF-induced DNA damage. Our study suggests that COFs may lead to DNA damage that is subjected to hOGG1-mediated repair pathways, and oxidative DNA damage may be involved in COF-induced carcinogenesis.     

DNA damage in Pakistani agricultural workers exposed to mixture of pesticides

A cross‐sectional study was designed to determine whether occupational exposure to a complex mixture of pesticides results in a significant increase of DNA damage in farmers chronically exposed to pesticides in open fields. Leukocytes from 47 agriculture workers exposed to pesticides and 50 controls were evaluated with comet assay. Workers recruitment was based on their exposure to pesticides during the spraying season on cotton crop. Serum from these individuals was also analyzed for pesticides presence using high performance liquid chromatography. Statistically significant difference (P < 0.001) in DNA damage of exposed individuals (mean ± S.D 14.80 ± 3.04 μm) was observed when compared with control group (6.54 ± 1.73 μm) as studied on the basis of comet tail length. Smokers had significantly higher mean comet tail length than nonsmokers and ex‐smokers in both workers (20.26 ± 3.53 vs. 14.19 ± 4.25, P < 0.001) and controls (7.86 ± 1.09 vs. 5.80 ± 1.59, P < 0.001), whereas age had a minimal effect on DNA damage (P < 0.05). The length of pesticide exposure is positively associated with DNA damage in exposed individuals (P < 0.001). Our study shows that chronic exposure to pesticides produces DNA damage in pesticide sprayers and suggests that this type of monitoring is recommended in preventive policies for pesticide sprayers. Environ. Mol. Mutagen., 2009. © 2008 Wiley‐Liss, Inc.     

Antiretroviral treatment monitoring with an improved HIV-1 p24 antigen test: an inexpensive alternative to tests for viral RNA

Monitoring of viral RNA has become indispensable for the management of HIV-1 infection, but is expensive. This study investigated whether a highly improved test for p24 antigen could serve as an alternative. Thirty-four patients enrolled during 1997 into two treatment studies were tested prospectively for viral RNA by the Roche HIV-1 Monitor and for p24 antigen using signal-amplification-boosted ELISA of heat-denatured plasma. P24 antigen was detectable in 75.8% of 178 samples and HIV RNA in 73.9% of 138 samples. The half-life of p24 antigen in the first phase of effective treatment was 1.6 +/-.4 days (RNA, 1.7 +/-.8). An apparent second, slower decay phase had a half-life of 42 +/- 16 days. Treatment failure occurred in 14 patients. Secondary treatment failures with RNA rebounds from undetectable levels to < or = 10(3) copies/ml in two patients with an undetectable viral load and 10(3) HIV RNA copies/ml, respectively, at baseline were not detected by p24 antigen but carried a low risk for secondary resistance mutations. The other 12 failures were on average detected 29 days earlier by p24 antigen than by RNA (P =.0204), owing to slightly more frequent testing for p24 than for RNA (2.7 vs. 2.4 tests). Average costs for p24 antigen testing up to a failure were only 20.5% of those for RNA (P <.0001). These results indicate that heat-denatured, amplification-boosted p24 antigen measurement can be used as a simple and inexpensive alternative to HIV RNA testing for monitoring treatment.     

Accuracy of quantitative HIV-1 RNA test methods at 1000 copies/mL and the potential impact of differences in assay calibration on therapy monitoring of patients

The World Health Organization (WHO) recommends the clinical use of a human immunodeficiency virus 1 (HIV-1) viral load (VL) threshold level of 1000 copies (cp)/mL in patients on antiretroviral therapy (ART) to distinguish between viral control (VL < 1000 cp/mL) and viral failure or poor adherence (VL > 1000 cp/mL). The accuracy of five quantitative HIV-1 RNA assays at this level was compared by replicate testing (n = 24) of 1000 cp/mL samples prepared from the Viral Quality Control (VQC) HIV-1 subtype B standard, which is in use for validation of nucleic acid testing methods since 1995. Until 2004 the VL assays reported geometric mean (95% confidence interval [CI]) values ranging between 449 (188-1067) and 3162 (3057-2367) cp/mL when using the Siemens bDNA 3.0 assay as reference method for an assigned value of 1000 (962-1038) cp/mL. In 2018, the following values (95% CI) were found by 24 replicate tests in each of the VL assays on the 1000 cp/mL samples: Abbott RealTime 1084 (784-1572), BioMerieux EasyQ 1110 (533-2230), Roche CAP/CTM 1277 (892-1828), Hologic Aptima 1616 (1324-1973), and Cepheid GeneXpert 2502 (1713-3655) cp/mL. Calibration studies involving three consecutive WHO replacement standards showed a significant drift in the amount of RNA copies per International Unit overtime. Heat inactivation of HIV-1 standards was found to cause a destandardizing effect. Our study underlines the limitations in HIV-1 RNA assay calibration based on frequently replaced WHO international standards. It is therefore proposed that clinicians interpret the recommended 1000 cp/mL alert level in therapy monitoring with an inaccuracy range of 500 to 2000 cp/mL.     

DNA damage in leukocytes of workers occupationally exposed to arsenic in copper smelters

Inorganic arsenic (i-As) is a known human carcinogen; however, humans continue to be exposed to i-As in drinking water and in certain occupational settings. In this study, we used the Comet assay to evaluate DNA damage in the somatic cells of workers from three Polish copper smelters who were occupationally exposed to i-As. Blood samples were collected from 72 male workers and 83 unexposed male controls and used for the detection of DNA damage, oxidative DNA damage, and DNA damage after a 3-hr incubation in culture. Urine samples were collected to assess the level of exposure. The mean concentration of arsenic metabolites in urine [the sum of arsenite (AsIII), arsenate (AsV), monomethylarsenate (MMA) and dimethylarsenate (DMA)] and the concentrations of DMA (the main metabolite in urine) were higher in workers than in controls, but the differences were not statistically significant. By contrast, the level of DNA damage, expressed as the median tail moment, was significantly higher in the leukocytes of workers than in the controls. Comet assays conducted with formamidopyrimidine glycosylase (FPG) digestion to detect oxidative DNA damage indicated that oxidative lesions were present in leukocytes from both the exposed and control groups, but the levels of damage were significantly higher among the workers. Incubation of the cells in culture resulted in a significant reduction in the levels of DNA damage, especially among leukocytes from the workers, suggesting that the DNA damage was subject to repair. Our findings indicate that copper smelter workers have increased levels of DNA damage in somatic cells, suggesting a potential health risk for the workers. Although i-As was present in air samples from the smelters and in urine samples from workers, no clear association could be made between i-As exposure and the DNA damage.