downregulation of stard8 in gastric cancer and its involvement in gastric cancer progression

Shuanglong Zhang,1,2,* Xiaojing Chang,1–3,* Jinguo Ma,2,4 Jing Chen,1 Yu Zhi,2 Zhenhua Li,2 Dongqiu Dai1,2 1Department of Gastrointestinal Surgery, The Fourth Affiliated Hospital, China Medical University, Shenyang, People’s Republic of China; 2Cancer Center, The Fourth Affiliated Hospital, China Medical University, Shenyang, People’s Republic of China; 3Department of Radiotherapy, The Second Hospital of Hebei Medical University, Shijiazhuang, People’s Republic of China; 4Hulun Buir People’s Hospital, Hulun Buir Medical School in Nationalities University of Inner Mongolia, Hulun Buir, People’s Republic of China *These authors contributed equally to this work Objective: Rho-GTPases play a pivotal role in a wide variety of signal transduction pathways and are associated with a great number of human carcinomas. STARD8, which is a Rho-GTPase-activating protein, has been proposed as a tumor suppressor gene, but its role in gastric cancer remains elusive. In this study, we investigate the expression of STARD8 in gastric cancer and its association with gastric cancer progression.Materials and methods: One normal gastric mucosa cell line for example GES1 and six human gastric cancer cell lines such as AGS, MGC803, MKN45, SGC7901, HGC27 and BGC823 were utilized to analyze STARD8 mRNA and protein levels by reverse transcription polymerase chain reaction (RT-PCR) and Western blot. A total of 70 paired gastric tissues including corresponding nonmalignant gastric tissues and cancer tissues were utilized to analyze the protein expression of STARD8 using immunohistochemistry, and the correlation between STARD8 level and clinicopathological features was also evaluated.Results: STARD8 was found to be downregulated in primary gastric cancer cells and tissues compared with the normal gastric mucosa cell line, GES1, and corresponding nonmalignant gastric tissues, while its decreased expression was significantly associated with TNM stage, lymph node metastasis and differentiation (p<0.05).Conclusion: There is significantly decreased expression of STARD8 in gastric cancer cells and tissues, and its expression may contribute to gastric tumorigenesis. Keywords: gastric cancer, STARD8, Rho-GTPase-activating proteins, metastasis