The junctional adhesion molecule (JAMs) family belongs to the immunoglobulin subfamily involved in the formation of tight junctions (TJ) in both endothelial and epithelial cells. RKO cells (RKO-JAM-2) and HT115 cells (HT115-JAM-2) showed retarded adhesion (P<0.05). An tumour model showed that RKO-JAM-2 had significantly reduced growth (P<0.05), invasion (P<0.05) and migration (P<0.05) as well as in HT115-JAM-2, except on proliferation and migration. Expression of JAM-2 resulted in a significant buy 288383-20-0 increase in TER and decrease in permeability of polarized monolayers (P<0.05). Further analysis of JAM-2 transcript levels against clinical aspects demonstrated that the decreasing JAM-2 expression correlated to disease progression, metastasis and poor survival. Taken together, JAM-2 may function as a putative tumour suppressor in the progression and metastasis of colorectal cancer. growth of RKO cell and had little effect on HT115. (B) Forced JAM-2 expression in RKO cells had inhibitory effect on ... Expression of JAM-2 influences MMP activity in colon cancer cells Invasive potential relates to the ability of tumour cells to degrade the extracellular matrix. We used gelatin zymography on supernatants from RKO and HT115 JAM-2 expression cells, which showed a decrease in MMP9 activity compared with pCMV-entry control buy 288383-20-0 cells (Fig. 4). Figure 4 MMP-9 expression after JAM-2 overexpression. Zymography showed that forced JAM-2 expression led to decreased secretion of MMP-9 by RKO and HT115 cells. Expression of JAM-2 decreases the trans-epithelial resistance (TER) and the permeability of polarized monolayers We next examined the effect of JAM-2 overexpression on TJ barrier function. JAM-2 had a significant effect on the TJ function of colon cancer cells. TER in both RKO and HT115 with JAM-2 expression cells were reduced, in comparison to that in empty plasmid control cells (RKOpCMV-entry and HT115pCMV-entry) and in wild-type cells (RKOWT and HT115WT) (P<0.01; Fig. 5A). In order to verify the TER results, we also detected the flux between polarized cells monolayers using paracellular perm-ability. This demonstrated that the higher the TER, the lower the permeability of polarized monolayers was with both FITC dextran 10 kDa and TRITC dextran 40 kDa (Fig. 5B and C). Figure 5 Effect of JAM-2 on the behaviour of RKO and HT115 cells. (A) JAM-2 expression increased the TER in both RKO and HT115 monolayer in comparison to that in empty plasmid control cells. (B) JAM-2 inhibits FITC flux of RKO and HT115 monolayer. (C) JAM-2 expression ... Discussion In the present study, we demonstrated that JAM-2 has low expression in colon cancer which is consistent with previous studies, where it was shown that JAM-2 is downregulated due to the JAM-2 gene having a hyper-methylated promoter at the CpG islands (20,22). We have also shown that JAM-2 expression exerts a significant effect on tumour metastasis and invasion. JAM-2 expression decreases the invasive properties of RKO and HT115 colon cancer (16) have shown that JAM-2 expression in endothelial cells contributed to murine B16 melanoma cell metastasis through interacting with JAM-C on tumour cells. The present study also detected the expression of JAM-2 in relation to colorectal cancer patient clinical data in a cohort of human colorectal cancer specimens through Rabbit Polyclonal to RPS2 quantitative PCR. Reduced transcript expression of JAM-2 was observed in the colon cancer tissue sections in comparison to normal background mammary tissues (P=0.042). This indicated that a loss of JAM-2 may occur as cells and normal tissues progress to a cancerous state. Following overexpression of JAM-2 in colon cancer cells, analysis of functional studies revealed a statistically significant reduction in JAM-2 expression in RKO cells as compared to controls in growth, migration, adhesion and invasion. This occurred in HT115 cells, although the effect on proliferation and migration was not as substantial. Cell-matrix adhesion plays a key step in cancer metastasis and is essential for invasion through matrix so as to progress the metastatic process. Numerous studies suggest matrix metalloproteases (MMP), a family of multidomain, zinc-containing neutral endopeptidases, to contribute to form a microenvironment that promotes tumour metastasis during early stages of tumourigenesis (24,25). Degradation of extracellular matrix components containing laminin, proteoglycans, collagen and other glycoproteins by MMPs facilitates proliferation, migration and metastasis of cancer cells, via blood and lymphatic routes (26). MMP-9-induced release of biological mediators from the extracellular matrix surrounding a cancer may compose a system by which stromal and neoplastic cells communicate. MMP-2 and MMP-9 are important members of MMPs family and their role has been studied in colon cancer (27). MMP-9 has been related to tumour buy 288383-20-0 progression in numerous studies (28C32). MMP-9 is regarded.