In vitro and in vivo evidence of metallopanstimulin-1 in gastric cancer progression and tumorigenicity

Purpose:The metallopanstimulin-1(MPS-1)gene is a growth factor-inducible gene,which is highly expressed in many human cancers and may be involved in the progression towards tumor malignancy.However,it is unclear whether MPS-1 plays any role in gastric cancer development or progression.Our studies were designed to clarify the MPS-1 expression pattern and to explore its potential role in gastric cancer.Experimental Design:The expression pattern of MPS-1 was determined in primary gastric cancer specimens and gastric cancer cell lines via immunohistochemistry and Western blotting.To investigate the functional significance of MPS-1 expression,three small interfering RNA(siRNA)expression plasmids were constructed and transfected into gastric cancer cell line SGC7901.The stable cell lines transfected with the siRNA targeting MPS-1 mRNA plasmids were selected and the biological features of these cells were examined.Results:MPS-1 was overexpressed in 86% of the gastric cancer tissues and all gastric cancer cells.In addition,MPS-1 expression was significantly increased and corresponded with the tumor-node-metastasis clinical stage,and was significantly higher in the late stage(P<0.01).The MPS-1 expression level was significantly decreased in the transfected cells with MPS-1-specific siRNA expression plasmid pRNAT-133.Furthermore,the stable transfected cancer cells exhibited an increase in the incidence of spontaneous apoptosis and a decrease in growth ability and tumorigenicity in nude mice.Conclusions:These results provide strong evidence that MPS-1 plays an important role in gastric cancer cell proliferation and development,and suggests that MPS-1 is a promising target for gastric cancer treatment.