Restoration of klotho gene expression induces apoptosis and autophagy in gastric cancer cells: tumor suppressive role of klotho in gastric cancer

Cancer Cell International

Lianwen Yuan¹  Jinhui Chen²  Jiapeng Zhou¹  Dong-cai Liu¹  Guoshun Shu¹  Jianping Zhou¹  Biao Xie² 

[1] Departemt of Geriatric Surgery, Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, China;Department of General Surgery, 8th Changsha Hospital, Changsha, Hunan, 410015, China

关键词: Autophagy;    Apoptosis;    Gastric cancer;    Klotho;   

Others  :  794310
DOI  :  10.1186/1475-2867-13-18

 received in 2013-01-20, accepted in 2013-02-13,  发布年份 2013

【 摘 要 】

Background

The loss of tumor suppressor gene expression is involved in the carcinogenesis of gastric cancer (GC). Klotho is a recently identified tumor suppressor gene that epigenetically inactivated in gastric cancer. However, the signaling pathways involved in the suppressive role of klotho have rarely been reported in gastric cancer. In this study, we investigated the involvement of klotho in gastric cancer cell proliferation, apoptosis, and autophagy as well as the associated signaling.

Methods

Methylation of klotho gene promoter in GC-7901, MNK-45 and AGS gastric cancer cells as well as GES-1 normal gastric epithelial cells was detected by bisulfate-based PCR. Restoration of klotho gene expression was established by applying a demethylating agent and delivering aklotho gene expression vector into GC-7901 cells. Cell viability was measured by CCK-8 assay. Cell apoptosis and cycling were analyzed by flow cytometry. Autophagy was measured by detecting LC3-I and LC3-II expression. Protein levels and phosphorylation were measured by Western blot assay.

Results

Methylation of klotho gene promoter and expression of the klotho gene were detected in GC cells. Restoration of klotho gene expression significantly inhibited cell proliferation, induced cell apoptosis, and increased LC3-I/LC3-II expression in GC cells. Restoration of klotho gene expression downregulated the phosphorylation levels of IGF-1 receptor, IRS-1, PI3K, Akt, and mTOR proteins. Both apoptosis and autophagy inhibitors blocked klotho-induced apoptosis and autophagy.

Conclusion

Klotho is a tumor suppressor in gastric cancer, which regulates IGF-1R phosphorylation and the subsequent activation of IRS-1/PI3K/Akt/mTOR signaling, tumor cell proliferation, apoptosis, and autophagy.

【 授权许可】

   
2013 Xie et al; licensee BioMed Central Ltd.

【 图 表 】

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