Inhibition Of Cancer Invasion And Metastasis By Endoplasmic Reticulum-Retained Anti-type Ⅳ Collagenase Intrabody

Invasion of malignant cancer cells requires the destruction of basement membrane (BM) and proteolysis of extracellular matrix (ECM). The MMPs are a family of zinc atom-dependent endopeptidases with specific and selective activities against many components of ECM. The enhanced expression of many MMPs has been correlated with the malignant phenotype of human cancer cells both in vivo and in vitro. In particular, the gelatinases are implicated with tumor invasion, as they degrade constituents of both the interstitial stroma and the subendothelial basement membrane matrix. Clinicopathologic studies have shown a correlation between the expression of MMP-2 and MMP-9 mRNA and the invasion and metastasis of human carcinomas.Functional knockout at the level of protein expression has been achieved via intrabody methods. This approach is based on intracellular expression of single-chain antibodies (scFv) to sequester target proteins during their biosynthesis, thus preventing their activity. Based on this concept, intracellular antibodies against type IV collagenase may have therapeutic use against tumor invasion and metastasis.In this study, we described the construction of an expression plasmid coding for an endoplasmic reticulum (ER)- retained, single chain antibody (ER.scFv) against the type IV collagenase. The intracellular antibody gene was transfected into the human fibrosarcoma HT1080 cell and the human lung cancer PG cell. The expression of the intracellular antibody was detected by Western blot. The immunohistochemistry analysis confirmed that ER.scFv was able to express locally in tumor cells. Immunoprecipitation from ER.scFv-transfected cells showed that the single chain...