Article

Hypomethylation of the DNMT3L promoter in ocular surface squamous neoplasia.

Ophthalmic Pathology Services, Kallam Anji Reddy Campus, L. V. Prasad Eye Institute, Hyderabad, India.
Archives of pathology & laboratory medicine (Impact Factor: 2.88). 08/2010; 134(8):1193-6. DOI: 10.1043/2009-0417-OA.1
Source: PubMed

ABSTRACT Cancer is known to have epigenetic inputs, with events like genomewide hypomethylation and gene-specific hypermethylation of DNA. The DNA methyltransferase enzymes act as effectors of this reprogramming. A previous study revealed that hypomethylation at the DNA methyltransferase 3-like (DNMT3L) promoter could be a potential biomarker in cervical tumors. Because the pathobiology of ocular surface squamous neoplasia (OSSN) is similar to that of cervical tumors, we wanted to determine whether similar changes occur in the methylation pattern at the DNMT3L promoter in OSSN.
To evaluate the methylation status of the DNMT3L promoter in OSSN compared with healthy conjunctiva.
We evaluated DNA methylation at the DNMT3L promoter in the tumor tissues of 6 patients with histologically proven OSSN and in healthy conjunctiva tissue from 7 individuals for controls using the sodium bisulfite-assisted conversion of genomic DNA. Extracted genomic DNA was treated with sodium bisulfite and amplified with specific primers for the DNMT3L promoter region. The specific polymerase chain reaction products were cloned and sequenced.
The mean age of these patients was 50.2 years (range, 35-65 years). Histologically, 4 OSSN cases were invasive; 2 were intraepithelial. Healthy conjunctival tissues exhibited a methylated promoter region, whereas a variable loss of methylation was observed in all 6 OSSN cases.
We have, for the first time to our knowledge, identified loss of methylation at the DNMT3L promoter in OSSN cases, but its physiologic significance is yet to be understood. Further studies are warranted to substantiate our results.

Download full-text

Full-text

Available from: Guru Prasad Manderwad, Jan 28, 2015
1 Follower
 · 
121 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: DNA methyltransferase 3-like (DNMT3L) is one of the key players in de novo DNA methylation of imprinting control elements and retrotransposons, which occurs after genome-wide epigenetic erasure during germ cell development. In this review, we summarise the biochemical properties of DNMT3L and discuss the possible mechanisms behind DNMT3L-mediated imprinting establishment and retrotransposon silencing in germ cells. We also discuss possible connections between DNMT3L and non-coding RNA-mediated epigenetic remodelling, the roles of DNMT3L in germ cell development and the implications in stem cell and cancer research.
    Biology of the Cell 06/2012; 104(10):571-87. DOI:10.1111/boc.201100109 · 3.87 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Ocular surface squamous neoplasia (OSSN) has a varied clinical presentation, the diagnosis of which rests on the histopathological examination of the excised lesion. The term OSSN includes mild dysplasia on one end of the spectrum and invasive squamous cell carcinoma on the other end. This lesion has a multi factorial aetiology with interplay of several factors like exposure to ultraviolet radiation, various chemical carcinogens and viral infections, however role of individual agents is not well understood. With the upsurge of infection with human immunodeficiency virus, a changing trend is seen in the clinical presentation and prognosis of patients of OSSN even in developed countries. Anterior segment optical coherence tomography (OCT) and confocal microscopy, hold promise in in-vivo differentiation of intraepithelial neoplasia from invasive squamous cell carcinoma. Variants of squamous cell carcinoma like Mucoepidermoid carcinoma, spindle cell carcinoma and OSSN associated with HIV infection should be suspected in a case of aggressive clinical presentation of OSSN or with massive and recurrent tumours. Surgery, chemotherapy and immunotherapy are the various treatment modalities which in combination show promising results in aggressive, recurrent and larger tumours.
    Saudi Journal of Ophthalmology 07/2013; 27(3):177-86. DOI:10.1016/j.sjopt.2013.07.002
  • [Show abstract] [Hide abstract]
    ABSTRACT: DNA methylation is an epigenetic mark involved in the control of genes expression. Abnormal epigenetic events have been reported in human pathologies but weakly documented in eye diseases. The purpose of this study was to establish DNMT mRNA and protein expression levels in the anterior eye segment tissues and their related (primary or immortalized) cell cultures as a first step towards future in vivo and in vitro methylomic studies. Total mRNA was extracted from human cornea, conjunctiva, anterior lens capsule, trabeculum and related cell cultures (cornea epithelial, trabecular meshwork, keratocytes for primary cells; and HCE, Chang, B-3 for immortalized cells). cDNA was quantified by real-time PCR using specific primers for DNMT1, 2, 3A, 3B and 3L. Immunolocalization assays were carried out on human cornea using specific primary antibodies for DNMT1, 2 and 3A, 3B and 3L. All DNMT transcripts were detected in human cornea, conjunctiva, anterior lens capsule, trabeculum and related cells but showed statistically different expression patterns between tissues and cells. DNMT2 protein presented a specific and singular expression pattern in corneal endothelium. This study produced the first inventory of the expression patterns of DNMTs in human adult anterior eye segment. Our research highlights that DNA methylation cannot be ruled out as a way to bring new insights into well-known ocular diseases. In addition, future DNA methylation studies using various cells as experimental models need to be conducted with attention to approach the results analysis from a global tissue perspective.
    Acta ophthalmologica 02/2014; 92(5). DOI:10.1111/aos.12365 · 2.51 Impact Factor