Overexpression of CRM1 indicates poor prognosis and its knockdown suppresses tumor growth in gastric cancer

Chromosome maintenance region 1 (CRM1), known as one of major nuclear exporters, plays a critical role in transmission of proteins and RNAs from nuclear to cytoplasm. Increasing studies have demonstrated that overexpression of CRM1 contributes to tumorigenesis and is closely related to tumor development and progression. However, the expression pattern, clinical significance and function of CRM1 in human gastric cancer have not been well characterized to date. In this study, we investigated the expression of CRM1 in 22 pairs of primary gastric cancer samples by quantitative real-time PCR and additional 71 gastric cancer samples by immunohistochemical staining on a tissue array. The results indicated that CRM1 was frequently upregulated in gastric cancer tissues and this upregulation was associated with tumor stage, tumor size, lymph node metastasis and distant metastasis of patients. Moreover, the patients with high expression of CRM1 were inclined to have shorter survival time than those with low expression of CRM1. Functionally, knockdown of CRM1 by RNA interference significantly inhibited the growth of gastric cancer cells in vitro and in vivo. In addition, the effect of downregulation of CRM1 on gastric cancer cells promoted cell death and altered some apoptosis-or cell cycle-related gene expression. Taken together, these findings suggest that CRM1 may facilitate to gastric cancer progression and serves as an indicator for poor prognosis and a potential therapeutic target for anticancer treatment.