RAB13 as a novel prognosis marker promotes proliferation and chemotherapeutic resistance in gastric cancer.

Gastric cancer (GC) is still a major lethal gastrointestinal tumor. In this study, we clarified that RAB13, which is a member of Rab GTPase family and responsible for cargos delivery between the Golgi and the plasma membrane, plays critical roles in the proliferation and the chemotherapeutic resistance in GC cells. Analyzing RAB13 expression in GC specimens, we found that its mRNA level was higher in cancerous tissues compared with normal counterparts and this increase was further associated with malignant progression of GC. Moreover, increased RAB13 indicated poor overall survival (OS) and progression free survival (PFS) in GC patients. We then found that deletion of RAB13 inhibited the proliferation and promoted the apoptosis in AGS and NCI-N87 cells, the impairments of viability which was due to reduced amount of RAB13 anchoring the plasma membrane and attenuated cellular response to EGF treatment and the activation of downstream Akt/ERK/mTOR signaling pathways accordingly. Moreover, in vitro experiments showed that RAB13 deletion enhanced the sensitization of AGS and NCI-N87 cells toward cisplatin (CDDP) and 5-fluorouracil (5-FU) treatment respectively. Together, these data demonstrate that RAB13 promotes the proliferation and confers CDDP and 5-FU resistance to GC cells, which provides experimental support to target this protein in future clinical practice.