Project description:Genomewide DNA methylation profiling of oral leukoplakia and oral sqamous cell carcinoma (OSCC) was performed to delineate candidate gene associated with progression and clinicopathological parameters. All tissue samples were collected after obtaining written informed consent. The DNA methylation profile of 74 OSCC and 22 leukoplakia were compared with 22 normal control tissues from healthy donor.
Project description:Objective This study aimed to investigate the expression and clinical significance of N6-methyladenosine (m6A) modification of circular RNA (circRNA) in oral leukoplakia (OLK) and oral squamous carcinoma cell (OSCC) tissues. Methods Using methylation RNA immunoprecipitation high-throughput sequencing technology (MeRIP-seq) and RNA high-throughput sequencing technology (RNA-seq), the first circRNA transcriptome analysis for detecting m6A methylationome profiles in OLK and OSCC tissues was obtained, followed by bioinformatics analysis. The qRT-PCR technique and protein immunoblotting technique were used to detect the expression of m6A methylesterase in OLK versus OSCC tissues. Results In this study, 275 differential m6A methylation peaks were identified in OLK and OSCC, among which 193 peaks were up-regulated and 82 were down-regulated. Additionally, 198 differential m6A methylation modified circRNAs were observed, with 127 up-regulated and 71 down-regulated (FC ≥ 2, P < 0.05). Most of the identified circRNAs that underwent m6A methylation alterations were derived from overlapping regions. It was found that the differential expression of circRNAs was not correlated with the joint analysis of significantly different m6A-circRNAs between the two groups. Furthermore, downregulation of mETTL14 and FTO protein levels was observed in OSCC tissues, although there were no discernible alterations in RNA levels. Conclusion Our study suggests that m6A methylation modification of circRNA may play a role in the development of oral leukoplakia, and that METTL14 and FTO may be important methylation enzymes that influence the development of oral leukoplakia. These findings may open up new research directions for in-depth investigations to clarify the molecular mechanisms of OLK carcinogenesis.
Project description:Genome wide DNA methylation profiling in oral cancer and oral leukoplakia patients. The cohort included 48 patients in total, with control, oral leukoplakia patients and oral cancer patients. The Infinium MethylationEPIC BeadChips 850K has been used to interrogate DNA methylation changes.
Project description:Array Comparative Genomic Hybridization (CGH) profiling of Oral Leukoplakia (OPL) and early stage Oral Squamous Cell Carcinoma (OSCC) was performed to delineate candidate non-random chromosomal loci associated with disease progression and clinico-pathological parameters. The array CGH hybridizations were performed for 24 OPL and 38 OSCC samples with pooled gender matched controls. All tissue samples were collected after obtaining written informed consent.
Project description:Gene Expression Profiling of Oral Leukoplakia (OPL) and Early Stage Oral Squamous Cell Carcinoma (OSCC) was performed to delineate candidate gene/s clusters with potential to distinguish normal, OPL and tumor tissue from Gingivobuccal complex. All tissue samples were collected after obtaining written informed consent. The RNA profile of 15 OPL and 34 OSCC samples was compared with 1 independent controls Gingivobuccal complex tissue from healthy donors.
Project description:RNAseq analysis of oral cancer and oral leukoplakia patients. Oral biopsies from 37 patients were obtained for sequencing using RNAseq including control, oral leukoplakia patients and oral cancer patients.
Project description:BackgroundGingivobuccal complex oral squamous cell carcinoma (GBC-OSCC) is an aggressive malignancy with high mortality often preceded by premalignant lesions, including leukoplakia. Previous studies have reported genomic drivers in OSCC, but much remains to be elucidated about DNA methylation patterns across different stages of oral carcinogenesis.ResultsThere is a serious lack of biomarkers and clinical application of biomarkers for early detection and prognosis of gingivobuccal complex cancers. Hence, in search of novel biomarkers, we measured genome-wide DNA methylation in 22 normal oral tissues, 22 leukoplakia, and 74 GBC-OSCC tissue samples. Both leukoplakia and GBC-OSCC had distinct methylation profiles as compared to normal oral tissue samples. Aberrant DNA methylation increases during the different stages of oral carcinogenesis, from premalignant lesions to carcinoma. We identified 846 and 5111 differentially methylated promoters in leukoplakia and GBC-OSCC, respectively, with a sizable fraction shared between the two sets. Further, we identified potential biomarkers from integrative analysis in gingivobuccal complex cancers and validated them in an independent cohort. Integration of genome, epigenome, and transcriptome data revealed candidate genes with gene expression synergistically regulated by copy number and DNA methylation changes. Regularised Cox regression identified 32 genes associated with patient survival. In an independent set of samples, we validated eight genes (FAT1, GLDC, HOXB13, CST7, CYB5A, MLLT11, GHR, LY75) from the integrative analysis and 30 genes from previously published reports. Bisulfite pyrosequencing validated GLDC (P = 0.036), HOXB13 (P < 0.0001) promoter hypermethylation, and FAT1 (P < 0.0001) hypomethylation in GBC-OSCC compared to normal controls.ConclusionsOur findings identified methylation signatures associated with leukoplakia and gingivobuccal complex cancers. The integrative analysis in GBC-OSCC identified putative biomarkers that enhance existing knowledge of oral carcinogenesis and may potentially help in risk stratification and prognosis of GBC-OSCC.
Project description:Objectives: Earlier studies involving a priori gene selection have identified promoter regions deregulated by DNA methylation changes in oral squamous cell cancers (OSCCs) and precancers. Interrogation of global DNA methylation patterns for such specimens has not been reported, though such analyses are needed to uncover novel molecular factors driving disease. Materials and Methods: We evaluated global DNA methylation patterns for 30 biopsies obtained from 10 patients undergoing surgical removal of an OSCC or carcinoma in situ (CIS). From a disease field in each patient, we collected i) dysplastic, ii) CIS or OSCC, and iii) adjacent normal biopsies. DNA isolated from each biopsy was profiled for methylation status using the Illumina HumanMethylation27K platform. Results: Our data demonstrate that aberrant methylation of promoter CpG islands exists across oral precancer and OSCC genomes. Non-hierarchical clustering of all methylation data revealed distinct methylation patterns between the normal and the CIS/OSCC tissues (with results for dysplastic biopsies split between groups). Multiple genes exhibiting recurrent aberrant DNA methylation were found for both dysplastic and CIS/OSCC groups, and included enrichment for genes found in the WNT and MAPK signaling pathways. Conclusion: In identifying aberrant DNA methylation at the earliest stages of oral precancer and finding recurring epigenetic disruption of specific genes/pathways across our analyzed cohort, we conclude that CpG methylation changes are a hallmark of oral cancer progression and that global DNA methylation analyses are an essential component for wider studies seeking to derive biomarkers or potentially druggable targets for improving oral cancer outcomes. Bisulphite converted DNA from the 30 samples were hybridised to the Illumina Infinium 27k Human Methylation BeadChip v1.2. Total RNA from 30 oral cancer samples were hybridized to Agilent 4x44k gene expression microarray.
Project description:Oral squamous cell carcinoma (OSCC) is one of the most common cancers worldwide including the Asian subcontinent. Oral carcinoma exhibits inherent heterogeneity in terms of the sites involved, etiology and pathology. They occur at multiple sites such as tongue, buccal mucosa, maxilla. Effective approaches towards improving survival rates in OSCC patients are primarily focused on early detection of the disease. The early clinical indication of the disease follows the development of potentially malignant lesions (leukoplakia/erythro-leukoplakia) with varied rates of transformation. Currently histopathological evaluation of oral biopsy is generally practiced to evaluate potential malignancy. However, human saliva has been considered to be a valuable medium for discovering biomarker molecules for malignancy. Exfoliated cancer cells may release protein or RNA molecules into the saliva or free molecules may be secreted or leaked from cancer cells representing gene expression changes associated with tumor development. Salivary proteins thus provide a strong option for development of non-invasive, point-of-care assays for screening/early detection of oral cancers. Dysplastic leukoplakia (LP) of the oral cavity is a potentially malignant condition for oral squamous cell carcinoma (OSCC), early detection of which is an unmet clinical need. In an effort to develop non-invasive biomarker based method for early detection of the disease, we have used quantitative mass spectrometry to identify differently abundant salivary proteins in OSCC (buccal mucosa) patients and individuals with potential to develop cancer (oral dysplastic leukoplakia) in comparison to healthy controls (with risk habits such as tobacco chewing or smoking).