Suppressed Tumor Cell Migration Research Articles

Snake venom inhibitors of collagen- and laminin-binding integrins suppress tumor cell migration and invasion

Snake venom inhibitors of collagen- and laminin-binding integrins suppress tumor cell migration and invasion

Sequence-specific silencing of MT1-MMP expression suppresses tumor cell migration and invasion: importance of MT1-MMP as a therapeutic target for invasive tumors.

Membrane-type 1 matrix metalloproteinase (MT1-MMP/MMP-14) has been believed a key enzyme in tumor invasion, because it is expressed in a variety of malignant human tumors, and overexpression of the enzyme enhances the ability of cellular invasiveness. However, it has not necessarily been clarified whether the endogenously expressed MT1-MMP in human tumors plays a critical role in their invasiveness. We used RNA silencing technology to downregulate the endogenous MT1-MMP expression in human tumor cells (fibrosarcoma HT1080 and gastric carcinoma MKN-28 cell lines), and evaluated the effect on the invasion of a reconstituted basement membrane (Matrigel). Transfection of a double-stranded RNA targeted to the MT1-MMP gene decreased the level of the enzyme to less than 10-20% without affecting production of other MMPs. According to the degree of silencing, activation of proMMP-2 was inhibited. CD44 shedding was also inhibited, but only in part. Decreased MT1-MMP levels were also reflected in reduced cell motility on hyaluronan (HA) and invasion in Matrigel. Thus, specific downregulation of MT1-MMP expression was sufficient to cause significant inhibition of the migration and invasion of tumor cells, even though other MMPs continued to be expressed.

Screening of natural compounds for inhibitory activity on colon cancer cell migration.

We examined the effects of 75 kinds of natural compounds, such as alkaloids, phenylpropanoids, flavonoids, steroids and terpenoids on the in vitro migration and proliferation of colon 26-L5 cells, in comparison with anti-cancer drugs used for chemotherapy. Twenty-three of the 75 compounds inhibited markedly tumor cell migration. Among the 23 compounds, evodiamine showed the most potent and selective inhibitory activity on tumor cell migration with an IC50 value of 1.25 microg/ml, which was about 20 times lower than that for tumor cell proliferation. The migratory inhibition reached about 70% at 10 microg/ml of evodiamine. On the other hand, most of anti-cancer drugs tested, except for paclitaxel, had little effect on tumor cell migration at the concentrations strongly inhibiting tumor cell proliferation. Paclitaxel suppressed tumor cell migration in a concentration-dependent manner and achieved about 70% inhibition at 10 microg/ml with a marginal effect on cell proliferation. These results suggest that evodiamine and paclitaxel may be regarded as leading compounds for anti-metastatic agents acting through the inhibition of tumor cell migration without cytotoxicity.

Attenuation of EGF receptor signaling by a metastasis suppressor, the tetraspanin CD82/KAI-1.

The 'metastasis suppressor' CD82/KAI-1, a member of the tetraspanin superfamily of transmembrane proteins, is widely distributed in normal tissues [1], and has been shown to be suppressed in the advanced stages of various epithelial malignancies [2-6]. Although the physiological relevance of this change is unknown, in vitro data show that ectopically expressed CD82/KAI-1 can suppress tumor cell migration, a process underlying the dissemination of tumor cells in vivo [5]. The function of CD82/KAI-1 is not known and it has been proposed that association of CD82/KAI-1 with other cell-surface proteins may be pivotal in directing its biological activities [7,8]. We show here that the CD82/KAI-1 tetraspanin is directly associated with the EGF receptor (EGFR), and that ectopic expression of CD82/KAI-1 in epithelial cells specifically suppresses EGF-induced lamellipodial extensions and cell migration. In cells expressing CD82/KAI-1, the initial activation of EGFR is not affected, but subsequent desensitization of EGF-induced signaling occurs more rapidly. This attenuation is correlated with an increased rate of receptor endocytosis. These results identify CD82/KAI-1 as a new regulator of EGF-induced signaling and show that the association of EGFR with the tetraspanin is critical in EGFR desensitization.

Effect of anticancer drugs on invasive capacity of human small-cell lung cancer cells in vitro

The effect of anticancer drugs on invasive capacity of Lu 135 human small-cell lung cancer cells was studied in vitro. the invasive capacity decreased in a dose-dependent manner when tumor cells were treated with the anticancer drugs cisplatin and etopside. The inhibition of tumor cell invasion was almost parallel with the inhibition of tumor cell growth. The anticancer drugs also suppressed tumor cell migration and the activity of the matrix-degrading protease, type IV collagenase, activity. But they did not suppress adhesion to basement membrane protein such as laminin, fibronectin, or type IV collagen. Because tumor cells express adhesion molecules on the cell surface, the effect of the anticancer drugs on the expression of one such molecule, integrin, was also studied. Lu 135 cells expressed alpha 4/beta 1 integrin on the cell surface, and the pattern of integrin expression did not change with exposure with the anticancer drugs. These data suggest that the anticancer drugs inhibit the invasive capacity by suppression of migration and type IV collagenase activity of tumor cells, and that they do not modulate adhesion to the extracellular matrix or cell surface adhesion molecules such as integrin. Furthermore, these findings indicate that anticancer drugs may be useful for anti-metastatic therapy in patients with small-cell lung cancer.