Loss of NDRG2 Expression Confers Oral Squamous Cell Carcinoma with Enhanced Metastatic Potential
CANCER RESEARCH
Authors: Tamura, Tomohiro; Ichikawa, Tomonaga; Nakahata, Shingo; Kondo, Yudai; Tagawa, Yuri; Yamamoto, Koji; Nagai, Kentaro; Baba, Takashi; Yamaguchi, Ryoji; Futakuchi, Mitsuru; Yamashita, Yoshihiro; Morishita, Kazuhiro
Abstract
Loss of the tumor suppressor NDRG2 has been implicated in the development of oral squamous cell carcinoma (OSCC), acting by modulating PI3K/AKT-mediated dephosphorylation of PTEN at S380/S382/T383 (STT). Here, we show that the majority of OSCC tumors with lymph node metastasis, a major prognostic factor, exhibit high levels of phosphorylated AKT-S473 and PTEN-STT and low levels of NDRG2 expression. In Ndrg2-deficient mice, which develop a wide range of tumors, we developed a model of OSCC by treatment with the tobacco surrogate 4-nitroquinoline-1-oxide (4-NQO). In this model, both the number and size of OSCC tumors were increased significantly by Ndrg2 deficiency, which also increased invasion of cervical lymph nodes. 4-NQO treatment of human OSCC cell lines exhibiting low NDRG2 expression induced epithelial-mesenchymal transition via activation of NF-kB signaling. Conversely, ectopic expression of NDRG2 reversed the EMT phenotype and inhibited NF-kB signaling via suppression of PTEN-STT and AKT-S473 phosphorylation. Our results show how NDRG2 expression serves as a critical determinant of the invasive and metastatic capacity of OSCC. (C) 2017 AACR.
Overexpression of NDRG2 Can Inhibit Neuroblastoma Cell Proliferation through Negative Regulation by CYR61
ASIAN PACIFIC JOURNAL OF CANCER PREVENTION
Authors: Zhang, Zhi-Guo; Li, Gang; Feng, Da-Yun; Zhang, Jian; Zhang, Jing; Qin, Huai-Zhou; Ma, Lian-Ting; Gao, Guo-Dong; Wu, Lin
Abstract
Several recent studies have showed that the n-myc downstream regulated gene 2 (NDRG2) is a new tumor suppressor gene, and that it plays an important role in tumor suppression in several cancers or cancer cell lines. However, few studies focused on its function in neuroblastoma cells. In the present investigation, we demonstrated that NDRG2 overexpression inhibited their proliferation. Using a cDNA microarray, we found that overexpression of NDRG2 inhibited the expression of cysteine-rich protein 61 (CYR61), a proliferation related gene. From our research, CYR61 may partially hinder NDRG2-mediated inhibition of cell proliferation. Overexpression of NDRG2 resulted in accumulation of cells in the G1 phase, which was accompanied by upregulation of p21 and p27 and downregulation of CDK4 and cyclin D1. Taken together, these data indicate that NDRG2 inhibits the proliferation of neuroblastoma cells partially through suppression of CYR61. Our findings offer novel insights into the physiological roles of NDRG2 in neuroblastoma cell proliferation, and NDRG2 may prove to be effective candidate for the treatment of children with neuroblastoma.