Understanding the Function, Expression and Regulatory Mechanism of N-myc Downstream Regulated Gene 1 and 3 in Human Bladder Cancer

• Main Authors: Ming Hsuan Chou, 周茗萱
• Other Authors: H. H. Juang
• Format: Others
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/28870211917300562525

碩士 === 長庚大學 === 生物醫學研究所 === 100 === Bladder cancer is the 5th most frequent malignant disease around worldwild. It is also the fourth of most common cancer of urologic system in Taiwan. Bladder cancer presents with few symptoms that aid in its detection. The frequently diagnosed cancer and lack of symptoms necessitates the development of a sensitive and specific detection tool using in bladder cancer. N-myc downstream regulated gene (NDRG) protein family consists of four members, including NDRG1, NDRG2, NDRG3, and NDRG4. NDRG1 has varied role for different cancers. In most cancers, NDRG1 inhibits cancer cell growth, differentiation, tumor formation and metastasis. However, NDRG1 existed high copy number in liver cancer cells, and related with the promotion of migration and invasion. The NDRG3 is found to be regulated by androgen, and stimulate cell proliferation and invasion, but a key role in cancer has not yet to understand. Results from [3H]-thymidine incorporation assay, in vitro matrigel invasion assay revealed that overexpression of NDRG1 in human bladder carcinoma cells attenuated cell proliferation and invasion, while knockdown NDRG1 increase cell invasion and migration in human bladder cancer cells. Overexpression of NDRG1 causes cell cycle arrested in human bladder cancer cells determining by flow cytometer assays. Xenografts animal study revealed that overexpression of NDRG1 decreased tumorigenesis in vivo. Results of immunoblot assays and RT-qPCR indicated that overexpression NDRG1 upregulated gene expression of prostate derived ets factor (PDEF) and CD82/KAI1 in HT-1376 cells. Knockdown of NDRG3 induced cell invasion, cell proliferation and accelerated cell cycle progression from G1 to S-phase in human bladder cancer cells. Moreover, we found that resveratrol induces NDRG1 and NDRG3 protein expression. Curcumin and luteolin also increase NDRG1 protein expression. Immunoblot and transient gene expression assays showed that overexpression p53 gene in HT-1376 cells promote NDRG1 and NDRG3 gene expression. Our results provide the notion of function of NDRG1 and NDRG3 in cell proliferasion, cell cycle and metastasis. In addition, anti-cancer drugs such as resveratrol inhibit cancer progression via upregulation of NDRG1 and NDRG3. Therefore, NDRG1 and NDRG3 are regarded as tumor suppressor genes in the human bladder carcinoma cells.