Epigenetic silencing of RASSF10 promotes tumor growth in esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most malignant diseases and the five year survival rate remains less than 10%. RASSF10 is a newly identified member of the Ras-association family, but the regulation and the function of RASSF10 in ESCC remain unclear. Research methodologies such as methylation specific PCR (MSP), semi-quantitative RT-PCR, immunohistochemistry, Sodium bisulfite sequencing, and colony formation assay were utilized in this investigation. Loss of RASSF10 expression was found in KYSE150 cells and reduced expression was found in KYSE70 and KYSE180 cells. Expression of RASSF10 was found in KYSE140, KYSE450, KYSE510, TE1, TE3, and TE8 cell lines. Complete methylation was found in KYSE30 and KYSE150 cells, partial methylation was found in KYSE70, KYSE180, KYSE510, and TE1, and unmethylation was found in KYSE140, KYSE450, TE3, and TE8. Re-expression or increased expression was induced by 5-Aza-dC treatment. RASSF10 was methylated in 44.3% primary esophageal squamous cell carcinoma. RASSF10 inhibits cell proliferation and induces G2/M phase arrest in esophageal cancer cells.

RASSF10 was frequently methylated in human esophageal squamous cell carcinoma and expression of RASSF10 was regulated by promoter region hypermethylation. RASSF10 may serve as a tumor suppressor of esophageal cancer.