In vitro and in silico validation of CA3 and FHL1 downregulation in oral cancer

Author(s)

Pereira, Claudia Maria ^{[1, 2]} ; de Carvalho, Ana Carolina ^{[3, 4]} ; da Silva, Felipe Rodrigues ^[5] ; Melendez, Matias Eliseo ^[3] ; Lessa, Roberta Cardim ^{[1, 2]} ; Andrade, Valeria Cristina C. ^[6] ; Kowalski, Luiz Paulo ^[1] ; Vettore, Andre L. ^{[4, 2]} ; Carvalho, Andre Lopes ^{[1, 7, 3]}

Affiliation

^[1] AC Camargo Canc Hosp, Dept Head & Neck Surg, Sao Paulo - Brazil

^[2] Ludwig Inst Canc Res, Lab Canc Genet, Sao Paulo - Brazil

^[3] Barretos Canc Hosp, Mol Oncol Res Ctr, Barretos - Brazil

^[4] Univ Fed Sao Paulo, Dept Sci Biol, UNIFESP, Diadema - Brazil

^[5] Embrapa Informat Agr, Campinas, SP - Brazil

^[6] Univ Fed Sao Paulo, Discipline Hematol & Hemotherapy, UNIFESP, Sao Paulo - Brazil

^[7] Barretos Canc Hosp, Dept Head & Neck Surg, Barretos, SP - Brazil

• Document type: Journal article
• Source: BMC CANCER; v. 18, FEB 17 2018.
• Web of Science Citations: 1

Abstract

Background: Aberrant methylation is a frequent event in oral cancer. Methods: In order to better characterize these alterations, a search for genes downregulated by aberrant methylation in oral squamous cell carcinoma (OSCC) was conducted through the mining of ORESTES dataset. Findings were further validated in OSCC cell lines and patients' samples and confirmed using TCGA data. Differentially expressed genes were identified in ORESTES libraries and validated in vitro using RT-PCR in HNSCC cell-lines and OSCC tumor samples. Further confirmation of these results was performed using mRNA expression and methylation data from The Cancer Genome Atlas (TCGA) data. Results: From the set of genes selected for validation, CA3 and FHL1 were downregulated in 60% (12/20) and 75% (15/20) of OSCC samples, respectively, and in HNSCC cell lines. The treatment of cell lines JHU-13 and FaDu with the demethylating agent 5'-aza-dC was efficient in restoring CA3 and FHL1 expression. TCGA expression and methylation data on OSCC confirms the downregulation of these genes in OSCC samples and also suggests that expression of CA3 and FHL1 is probably regulated by methylation. The downregulation of CA3 and FHL1 observed in silico was validated in HNSCC cell lines and OSCC samples, showing the feasibility of integrating different datasets to select differentially expressed genes in silico. Conclusions: These results showed that the downregulation of CA3 and FHL1 data observed in the ORESTES libraries was validated in HNSCC cell lines and OSCC samples and in a large cohort of samples from the TCGA database. Moreover, it suggests that expression of CA3 and FHL1 could probably be regulated by methylation having an important role the oral carcinogenesis. (AU)

• FAPESP's process: 05/02580-8 - Evaluation of methylation profile as prognostic marker in patients with head and neck tumors
• Grantee: Andre Luiz Vettore de Oliveira
• Support Opportunities: Regular Research Grants