title: Epigenetic regulation of the pro-apoptosis gene TSSC3 in human osteosarcoma cells.
abstract: Promoter hypermethylation can lead to a loss of genetic imprinting in carcinogenesis. The mechanism for the loss of expression of the imprinted gene TSSC3 has not been investigated in cases of osteosarcoma. In this study, we treated osteosarcoma cell lines with 5-Aza-CdR, which is a widely-used DNA methyltransferase inhibitor, and found dose-dependent reduction in cell growth, conversion of cell morphology to a non-motile phenotype, and obvious increase in apoptosis. In addition, we also found that 5-Aza-CdR reactivated TSSC3 expression through demethylation of the promoter regions. These findings indicate that the TSSC3 gene is silenced through hypermethylation of the promoter regions, a mechanism commonly associated with gene silencing in cancer. Finally, we examined the role of TSSC3 in human osteosarcoma SaOS2 cells. We showed that TSSC3 overexpression suppressed SaOS2 cell growth and increased apoptosis through caspase-3 upregulation, thereby, suggesting that TSSC3 may play a pro-apoptosis role to maintain the normal balance of growth. Taken together, these observations suggest that the epigenetic regulation of TSSC3, a pro-apoptosis gene, provides valuable insights into possible osteosarcoma therapies.
authors.affiliation: Department of Pathology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Pathology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
authors.forename: Yusheng
authors.initials: Y
authors.lastname: Huang
authors.affiliation: Department of Pathology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
authors.forename: Yangfan
authors.initials: Y
authors.lastname: Lv
authors.affiliation: Department of Pathology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China.
authors.forename: Gang
authors.initials: G
authors.lastname: Meng
authors.affiliation: Department of Pathology, Xinqiao Hospital, Third Military Medical University, Chongqing 400037, China. Electronic address: qiaonan85@263.net.
authors.forename: Qiao-Nan
authors.initials: QN
authors.lastname: Guo
mesh_terms: D000964:Antimetabolites, Antineoplastic / Q000008:administration & dosage / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects / Q000235:genetics; D001374:Azacitidine / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D001859:Bone Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D053148:Caspase 3 / Q000235:genetics; D045744:Cell Line, Tumor; D019175:DNA Methylation / Q000235:genetics; D000077209:Decitabine; D004305:Dose-Response Relationship, Drug; D044127:Epigenesis, Genetic; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D020868:Gene Silencing; D006801:Humans; D009687:Nuclear Proteins / Q000235:genetics; D012516:Osteosarcoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D011401:Promoter Regions, Genetic / Q000235:genetics; D015854:Up-Regulation / Q000235:genetics
chemical_list: D000964:Antimetabolites, Antineoplastic; D009687:Nuclear Proteins; C109277:TSSC3 protein; D000077209:Decitabine; D053148:Caspase 3; D001374:Azacitidine
keywords: 5-Aza-CdR; Methylation; Osteosarcoma; TSSC3