Preliminary Study On The Correlation Between Co-stimulatory Molecule B7-H3and Invasion In Colorectal Cancer

Objective:Co-stimulatory molecule B7-H3, as one of the important immune molecules, plays a key role in the development of colorectal cancer. However, up to50%of the patients will be diagnosed with liver metastases. It has been confirmed to be relative with matrix metalloproteinases (MMPs). This paper will analyze the regulation of B7-H3to MMPs, and investigate the relationship between B7-H3and invasion or metastasis in colorectal cancer, from the perspective of the non-immunological function of B7-H3.Methods:1. Immunohistochemistry detected the expression of B7-H3, MMP2and MMP9in87cases of colorectal cancer specimens. B7-H3, MMP2or MMP9staining intensity was scored as negative (0), faint (1+), moderate (2+) or strong (3+), respectively and the slides were read by two separate pathologists independently.2. We constructed the recombinant expression vector of the full length B7-H3gene. After validation of screening, Real-time PCR, Western Blot and laser confocal, we needed to obtain SW480stable colon cancer cell line which was overexpression of B7-H3.3. We established SW480knockdown cell model with B7-H3siRNA fragment. Western Blot detected the expression of MMP2and MMP9, and Transwell analyzed the ability of cell invasion with B7-H3overexpression or interference.Results:1. The expression of B7-H3in patients with colorectal cancer was associated with T staging of TNM rather than N staging. Both the expression of MMP2and MMP9was increasingly correlated with that of B7-H3in colorectal cancer tissues, especially MMP9and B7-H3had a good linear relationship.2. SW480stable control and B7-H3overexpression cell lines were constructed successfully, named SW480-NC and SW480-B7-H3respectively. 3. B7-H3expression knockdown cell lines were established successfully, named SW480-B7-H3+kd. When B7-H3was highly expressed, the expression level of MMP2and MMP9, or the capability of cell invasion were markedly enhanced, In contrast, after the expression of B7-H3was interference, both the expression of MMPs and the ability of cell invasion were weakened obviously.Conclusions:1. High level of B7-H3protein promoted tumor invasion rather than region lymph nodal metastasis in colorectal cancer tissue. Furthermore, the expression of B7-H3had a close relationship with matrix metalloproteinases MMP2and MMP9.2. We obtained stably transfected cell lines, so we could research deeply on biological function and signaling pathways involved of B7-H3in colorectal cancer.3. Overexpression of B7-H3in colon cancer cells increased the expression of invasion-related matrix matalloproteinases, and promoted the invasion and metastasis of cancer cells.Overall, this paper confirmed that B7-H3expression was positively correlated with MMPs, from the cell and tissue, promoted the invasion and metastasis of the tumor.