Overexpression of CPXM2 predicts an unfavorable prognosis and promotes the proliferation and migration of gastric cancer

Carboxypeptidase X, M14 family member 2 (CPXM2), has been associated with several human disorders such as developmental diseases. However, whether CPXM2 is involved in oncogenesis or tumor progression remains unclear. In the present study, we used clinical samples from gastric cancer (GC) patients to investigate potential roles of CPXM2 in GC. We also analyzed datasets from the Oncomine database, The Cancer Genome Atlas (TCGA), and the Kaplan-Meier Plotter to validate these results. We found that CPXM2 was overexpressed in GC and that the overexpression was associated with an unfavorable prognosis, regardless of the Lauren classification and tumor node metastasis staging. In addition, knockdown of CPXM2 in cultured GC cells significantly impeded cell proliferation and migration, as indicated by the cholecystokinin octapeptide, colony formation assay, scratch wound healing assay, and Transwell(®) migration assay. Furthermore, gene set enrichment analysis using RNA-seq data from TCGA indicated that high CPXM2 expression in GC patients was positively correlated with the HALLMARK_APICAL_JUNCTION and HALLMARK_EPITHELIAL_MESENCHYMAL_TRANSITION gene sets. Finally, western blotting results revealed that several key molecules involved in the epithelial mesenchymal transition were regulated by CPXM2. Taken together, these results imply an active role for CPXM2 in promoting tumor aggressiveness via epithelial to mesenchymal transition (EMT) modulation in GCs.