Proteomics analysis of two mice hepatocarcinoma ascites syngeneic cell lines with high and low lymph node metastasis rates provide potential protein markers for tumor malignancy attributes to lymphatic metastasis

Lymph node metastasis (LNM) is recognized as an important factor involved in the tumor malignancy progression. Our previous study has indicated that the hepatocarcinoma cell line with 75% of LNM (Hca-F)-cell-induced neoplasia and the hepatocarcinoma cell line with 25% of LNM-induced neoplasia are accompanied with high (75%) and low (25%) incidences of LNM. In the current study, 62 and 54 protein spots were observed up-regulated and down-regulated in Hca-F cell relative to the hepatocarcinoma cell line with 25% of LNM by 2-D DIGE. Totally, 113 unique proteins were identified by HPLC-nano ESI-MS/MS analysis. The expression levels of Annexin A7, Ulch3, and ER protein 29 were validated by Western blotting analyses. The abnormally regulated proteins were categorized and annotated by protein analysis through evolutionary relationships analysis with the aid of the database for annotation, visualization and integrated discovery tool. Seventeen gene candidates concordantly expressed both at mRNA and protein levels. By making a challenge, we detected expression levels of Annexin A7 in primary gastric cancer (GC) and primary GC cancer tissues with LNMs by immunohistochemisty. Higher ratio of positive and strong expressions Annexin A7 in GC might correlate with the tumor progression. The repression of Annexin A7 inhibits the mobility and invasion abilities of Hca-F cell, increases the apoptosis rate of Hca-F cell. Current study narrows and provides certain specific protein candidates potentially playing important roles in LNM-associated cancers.