alexa Patterns and possible roles of LINE-1 methylation changes in smoke-exposed epithelia.
Genetics & Molecular Biology

Genetics & Molecular Biology

Gene Technology

Author(s): Wangsri S, Subbalekha K, Kitkumthorn N, Mutirangura A

Abstract Share this page

Abstract Tobacco smoking and reduced methylation of long interspersed element-1 (LINE-1) are crucial in oral carcinogenesis. 5'UTR of human LINE-1 sequence contains several CpG dinucleotides which are methylated in various proportions (0-100\%). Methylation levels of many LINE-1s in cancer were reduced, hypomethylated. The hypomethylation of each LINE-1 locus can promote instability of genome and repress expression of a gene located on that same chromosome. This study investigated if cigarette smoking influences LINE-1 methylation of oral mucosal cells. The methylation of human LINE-1 in clinically normal oral mucosa of current smokers was compared to non-smokers. By using the combined bisulphite restriction analysis, each LINE-1 sequence was categorised into 4 patterns depending on the methylation status and location of the two 18-bp successive CpG from 5' to 3' including (m)C(m)C, (u)C(u)C, (m)C(u)C and (u)C(m)C. Of these, (m)C and (u)C represent methylated and unmethylated CpG, respectively. The DNA bisulphite sequence demonstrated that most CpGs of (m)C(m)C and (u)C(u)C were methylated and unmethylated, respectively. Nevertheless, some CpGs of each (m)C(u)C or (u)C(m)C allele were methylated. Imaging of the digestion products was used to generate \%methylation value. No significant difference in the overall LINE-1 methylation level but the differences in percentages of some methylation patterns were discovered. The \%(m)C(m)C and \%(u)C(u)C increased, while the \%(m)C(u)C decreased in current smokers (p = 0.002, 0.015, and <0.0001, respectively). Additionally, the lower \%(m)C(u)C still persisted in persons who had stopped smoking for over 1 year (p = 0.001). The \%(m)C(u)C also decreased in the higher pack-year smokers (p = 0.028). Smoking possibly altered (m)C(u)C to (m)C(m)C and (u)C(u)C forms, and changes (u)C(m)C to (u)C(u)C forms. In conclusion, smoking changes methylation levels of partial methylated LINE-1s and increased the number of hypo- and hypermethylated loci. These hypomethylated LINE-1s may possess carcinogenesis potential. Moreover, LINE-1 methylation patterns may be useful for monitoring oral carcinogenesis in smokers.
This article was published in PLoS One and referenced in Gene Technology

Relevant Expert PPTs

Relevant Speaker PPTs

Recommended Conferences

  • 2nd International Conference and Expo on Generic Drug Market and Contract Manufacturing
    September 25-26, 2017 Frankfurt, Germany
  • 6th International Conference and Exhibition on Cell and Gene Therapy
    Mar 27-28, 2017 Madrid, Spain
  • 2nd World Congress on Human Genetics & Genetic Disorders
    November 02-03, 2017 Toronto, Canada

Relevant Topics

Peer Reviewed Journals
 
Make the best use of Scientific Research and information from our 700 + peer reviewed, Open Access Journals
International Conferences 2017-18
 
Meet Inspiring Speakers and Experts at our 3000+ Global Annual Meetings

Contact Us

 
© 2008-2017 OMICS International - Open Access Publisher. Best viewed in Mozilla Firefox | Google Chrome | Above IE 7.0 version
adwords