The Role of FAS Receptor Methylation in Osteosarcoma Metastasis

Authors

Jiayi M Sun
Wing-Yuk Chow
Gufeng Xu
M John Hicks
Manjula Nakka
Jianhe Shen
Patrick Kwok Shing Ng
Aaron M Taylor
Alexander Yu
Jason E Farrar
Donald A Barkauskas
Richard Gorlick
Jaime M Guidry Auvil
Daniela Gerhard
Paul Meltzer
Rudy Guerra
Tsz-Kwong Man
Ching C Lau
On Behalf Of The Target Osteosarcoma Consortium

Publication Date

7-29-2023

Journal

International Journal of Molecular Sciences

DOI

10.3390/ijms241512155

PMID

37569529

PMCID

PMC10418590

PubMedCentral® Posted Date

7-29-2023

PubMedCentral® Full Text Version

Post-print

Published Open-Access

yes

Keywords

Mice, Animals, fas Receptor, Bone Neoplasms, Osteosarcoma, Azacitidine, DNA Methylation, CpG Islands, Cell Line, Tumor, osteosarcoma, FAS receptor, DNA methylation, 5-azacytidine, prognosis

Abstract

Osteosarcoma is the most frequent primary malignant bone tumor with an annual incidence of about 400 cases in the United States. Osteosarcoma primarily metastasizes to the lungs, where FAS ligand (FASL) is constitutively expressed. The interaction of FASL and its cell surface receptor, FAS, triggers apoptosis in normal cells; however, this function is altered in cancer cells. DNA methylation has previously been explored as a mechanism for altering FAS expression, but no variability was identified in the CpG island (CGI) overlapping the promoter. Analysis of an expanded region, including CGI shores and shelves, revealed high variability in the methylation of certain CpG sites that correlated significantly with FAS mRNA expression in a negative manner. Bisulfite sequencing revealed additional CpG sites, which were highly methylated in the metastatic LM7 cell line but unmethylated in its parental non-metastatic SaOS-2 cell line. Treatment with the demethylating agent, 5-azacytidine, resulted in a loss of methylation in CpG sites located within the FAS promoter and restored FAS protein expression in LM7 cells, resulting in reduced migration. Orthotopic implantation of 5-azacytidine treated LM7 cells into severe combined immunodeficient mice led to decreased lung metastases. These results suggest that DNA methylation of CGI shore sites may regulate FAS expression and constitute a potential target for osteosarcoma therapy, utilizing demethylating agents currently approved for the treatment of other cancers.