Long interspersed nuclear element ORF-1 protein promotes proliferation and resistance to chemotherapy in hepatocellular carcinoma

AIM:To clarify the specific roles and mechanisms of long interspersed nuclear element-1 ORF-1 protein [human long interspersed nuclear element-1(LINE-1),ORF-1p] in chemotherapeutic drug resistance and cell proliferation regulation in hepatocellular carcinoma(HCC) cells.METHODS:MTT assays were performed to identify the effect of the chemotherapeutic drug toxicity on HepG2 cells.Cell proliferation inhibition and the IC 50 were calculated by the Origin 8.0 software.Western blotting assays were performed to investigate whether LINE-1 ORF-1p modulates the expression of some important genes,including p53,p27,p15,Bcl-2,mdr,and p-gp.To corroborate the proliferation and anchor-independent growth results,the HepG2 cells were analyzed by flow cytometry to investigate the effect of LINE-1 ORF1p on the apoptosis regulation.RESULTS:LINE-1 ORF-1p contributed to the resistance to several chemotherapeutic drugs(cisplatin and epirubicin) in HepG2 cells.The IC 50 of the epirubicin and cisplatin increased from 36.04 nmol/L to 59.11 nmol/L or from 37.94 nmol/L to 119.32 nmol/L.Repression of LINE-1 ORF-1p expression by the siRNA could markedly enhance the response of HepG2 cells to the epirubicin and cisplatin.The IC 50 correspondingly decreased from 28.06 nmol/L to 3.83 nmol/L or from 32.04 nmol/L to 2.89 nmol/L.Interestingly,down-regulation of LINE-1 ORF-1p level by siRNA could promote the response of HepG2 cells to the paclitaxel.The IC 50 decreased from 35.90 nmol/L to 7.36 nmol/L.However,overexpression of LINE-1 ORF-1p did not modulate the paclitaxel toxicity in HepG2 cells.Further Western blotting revealed that LINE-1 ORF-1p enhanced mdr and p-gp gene expression.As a protein arrested in the nucleus,LINE-1 ORF-1p may function through modulating transcriptional activity of some important transcription factors.Indeed,LINE-1 ORF-1p promoted HepG2 cell proliferation,anchor-independent growth and protected the cells against apoptosis through modulating the expression of p15,p21,p53,and Bcl-2 genes.CONCLUSION:LINE-1 ORF-1p promotes HepG2 cell proliferation and plays an important role in the resistance of chemotherapeutic drugs.By establishing novel roles and defining the mechanisms of LINE-1 ORF1p in HCC chemotherapeutic drug resistance and cell proliferation regulation,this study indicates that LINE-1 ORF-1p is a potential target for overcoming HCC chemotherapeutic resistance.

Long interspersed elements in three species of Gracilaria (Gracilariaceae, Rhodophyta)

In order to find out whether long interspersed elements （LINEs） existed in macro-algae gehomes or not, we tested the LINE homologues in representative families （species）： Gracilaria （G. eucheumoides Harv., G. tenuistipitata Chang et Xia, and G. textorii （Sur） De-Toni）, Laminaria （L. longissima Miyabe and L. japonica Aresch.）, and Ulva （U. lactuca L. and U. pertusa Kjellm.） during 2004 to 2005. Polymerase Chain Reaction （PCR） was carried out with degenerate oligonucleotide primers designed from LINEs of rice homologues and Cin4 of maize. Cloning and nucleotide sequencing of the PCR products revealed that 4 clones that derived from 3 species of Gracilaria have LINE homologues. The nucleotide sequences of the 4 LINE homologues diverged greatly, but the amino acid sequences deduced from them were relatively conserved. The endonuclease regions of the LINE homologues greatly diverged from that of other plants, but they had closer phylogenetic relationship to Zepp elements in Chlorella sp., which indicated that sequence divergence by vertical transmission has been a major influence on the evolution of algal LINEs.

Association between Long Interspersed Nuclear Element-1 Methylation and Relative Telomere Length in Wilms Tumor

Background： DNA hypomethylation of long interspersed nuclear elements- 1 （LINEs- 1 ） occurs during carcinogenesis, whereas intbmaation addressing LINE-1 methylation in Wilms tumor （WT） is limited. The main purpose of our study was to quantity, LINE-1 methylation levels and evaluate their relationship with relative telomere length （TL） in WT. Methods： We investigated LINE-1 methylation and relative TL using bisulfite-polymerase chain reaction （PCR） pyrosequencing and quantitative PCR, respectively, in 20 WT tissues, 10 normal kidney tissues and a WT cell line. Significant changes were analyzed by t-tests. Results： LINE-1 methylation levels were significantly lower （P 〈 0.05） and relative TLs were sigmificantly shorter （P 〈 0.05） in WT compared with normal kidney. There was a significant positive relationship between LINE- 1 methylation and relative TL in WT （r = 0.671, P = 0.001 ）. LINE- 1 Methylation levels were significantly associated with global DNA methylation （r = 0.332, P 〈 0.01 ）. In addition, relative TL was shortened and LINE- 1 methylation was decreased in a WT cell line treated with the hypomethylating agent 5-aza-2＇-deoxycytidine compared with untreated WT cell line. Conclusion： These results suggest that LINE-1 hypomethylation is common and may be linked to telomere shortening in WT.

Global hypomethylation in hepatocellular carcinoma and its relationship to aflatoxin B_1 exposure

AIM:To determine global DNA methylation in paired hepatocellular carcinoma(HCC) samples using several different assays and explore the correlations between hypomethylation and clinical parameters and biomarkers,including that of aflatoxin B 1 exposure.METHODS:Using the radio labeled methyl acceptance assay as a measure of global hypomethylation,as well as two repetitive elements,including satellite 2(Sat2) by MethyLight and long interspersed nucleotide elements(LINE1),by pyrosequencing.RESULTS:By all three assays,mean methylation levels in tumor tissues were significantly lower than that in adjacent tissues.Methyl acceptance assay log(mean ± SD) disintegrations/min/ng DNA are 70.0 ± 54.8 and 32.4 ± 15.6,respectively,P = 0.040;percent methylation of Sat2 42.2 ± 55.1 and 117.9 ± 88.8,respectively,P < 0.0001 and percent methylation LINE1 48.6 ± 14.8 and 71.7 ± 1.4,respectively,P < 0.0001.Aflatoxin B 1 albumin(AFB 1-Alb) adducts,a measure of exposure to this dietary carcinogen,were inversely correlated with LINE1 methylation(r =-0.36,P = 0.034).CONCLUSION:Consistent hypomethylation in tumor compared to adjacent tissue was found by the three different methods.AFB 1 exposure is associated with DNA global hypomethylation,suggesting that chemical carcinogens may influence epigenetic changes in humans.

Harnessing the potential of gene editing technology using CRISPR in inflammatory bowel disease

The molecular scalpel of clustered regularly interspersed short palindromic repeats/CRISPR associated protein 9(CRISPR/Cas9) technology may be sharp enough to begin cutting the genes implicated in inflammatory bowel disease(IBD) and consequently decrease the 6.3 billion dollar annual financial healthcare burden in the treatment of IBD. For the past few years CRISPR technology has drastically revolutionized DNA engineering and biomedical research field. We are beginning to see its application in gene manipulation of sickle cell disease,human immunodeficiency virus resistant embryologic twin gene modification and IBD genes such as Gatm(Glycine amidinotransferase, mitochondrial),nucleotide-binding oligomerization domain-containing protein 2, KRT12 and other genes implicated in adaptive immune convergence pathways have been subjected to gene editing, however there are very few publications. Furthermore,since Crohn's disease and ulcerative colitis have shared disease susceptibility and share genetic gene profile, it is paramount and is more advantageous to use CRISPR technology to maximize impact. Although, currently CRISPR does have its limitations due to limited number of specific Cas enzymes, off-target activity,protospacer adjacent motifs and crossfire between different target sites. However,these limitations have given researchers further insight on how to augment and manipulate enzymes to enable precise gene excision and limit crossfire between target sites.

Effect of Nitrogen on Growth and Yield of Pineapple Grown on BRIS Soil

The physical and chemical properties of BRIS （beach ridges interspersed with swales） soil are unsuitable for agricultural purposes. A proper fertilizer and crop management practices are required. The relationship between different level of nitrogen fertilizer, growth and pineapple fruit yield vary N36 were studied. The experiment was conducted using randomized complete block design of seven treatments with four replicates, Prior to artificial flower induction, seven different rates of nitrogen fertilizer at 0, 200, 400, 600, 800, 1,000 and 1,200 kg-ha^-1 were applied in four equal split doses. As the level of nitrogen fertilizer was increased, a decrease in acidity of fruits and an increase in crown weight were observed. However an increase in mean length of D leaf, mean fruit length, mean fruit weight, mean fruit to crown ratio were obtained as the rate of nitrogen fertilizer was increased from 0-600 kg.N-ha^-1. Further increase however led to a decrease in the same parameters.

IGF2 differentially methylated region hypomethylation in relation to pathological and molecular features of serrated lesions

AIM: To investigate insulin-like growth factor 2 (IGF2) differentially methylated region (DMR)0 hypomethylation in relation to clinicopathological and molecular features in colorectal serrated lesions.

Molecular epidemiology of Mycobacterium tuberculosis in Gansu province of China

Background Mycobacterial interspersed repetitive units-variable number tandem repeat （MIRU-VNTR） and Beijing family typing based on detecting the deletion of RD105 sequence are two common genotyping methods used to study the molecular epidemiologic characteristics of Mycobacterium （M.） tuberculosis. We collected 218 strains of M. tuberculosis between 2004 and 2006 in the Linxia Hui Autonomous Prefecture of Gansu province in Northwest China. Methods MIRU-VNTR analysis and Beijing family typing based on detecting the deletion of RD105 sequence were used to type the 218 strains, and their typing power was evaluated to look for practical and efficient genotyping methods suitable for the region. Results The MIRU typing yielded 115 distinct genotypes, including 98 unique isolates and 17 different clusters containing 120 isolates （55.05%）; the cluster rate was 47.25%. By detecting the deletion of RD105 sequence, 188 of 218 （86.23%） isolates belonged to Beijing family. Combination of Beijing family typing and MIRU typing yielded 118 distinct patterns, including 101 unique isolates and 17 clusters containing 117 isolates （54.13%）. The largest cluster contained 58 strains with MIRU genotype of 223325173533 which contained 50 strains belonging to Beijing family and 8 strains belonging to non-Beijing family. Conclusions The Beijing family strains occupied a large proportion and the Beijing family MIRU genotype 223325173533 is a dominant strain in Linxia of Gansu. Combining detecting the deletion of RD105 and MIRU typing together provides a simple, fast, and effective method which is low in cost and might be practical and suitable for M. tuberculosis aenotvDina in China.