Antimetastatic Effect by Anti‐adhesion Therapy with Cell‐adhesive Peptide of Fibronectin in Combination with Anticancer Drugs

We have investigated the therapeutic effect of CH‐271 fusion polypeptide containing both cell‐binding domain (C‐274) and heparin‐binding domain (H‐271) of fibronectin in combination with anticancer drugs such as doxorubicin (DOX) or mitomycin C (MMC) on tumor metastasis of different types of tumors. CH‐271 fusion polypeptide alone significantly inhibited both liver and lung metastasis when it was co‐injected with L5178Y‐ML25 T‐lymphoma, RAW117‐H10 B‐lymphoma or B16‐BL6 melanoma cells, and spontaneous lung metastasis of B16‐BL6 melanoma cells when administered i.v. seven times before or after surgical excision of the primary tumors. Combined treatments with CH‐271 and either DOX or MMC significantly inhibited liver and lung metastasis of lymphoma or melanoma cells respectively, as compared with either treatment alone or the untreated control. Administrations of CH‐271 and DOX in combination substantially prolonged the survival time of mice injected i.v. with L5178Y‐ML25 cells. CH‐271 or DOX was effective for inhibiting the invasion of LS178Y‐ML25 cells into Matrigel in a concentration‐dependent manner. Our previous study has shown that CH‐271‐mediated inhibition of tumor invasion may be due in part to the anti‐cell adhesive property without affecting the cell growth, whereas the anti‐invasive effect of DOX was established to have resulted from the growth inhibition of tumor cells. Moreover, the combination of CH‐271 with DOX provided a more effective inhibition of tumor invasion into Matrigel than did either alone. Thus, we have demonstrated that the combination of anti‐cell adhesive CH‐271 and anticancer drugs such as DOX or MMC, i.e. anti‐adhesion therapy and chemotherapy, is a new approach that offers enhanced (additive) inhibitory effects on tumor metastasis and invasion.