Studies on transplantation of the laminin receptor and its roles in experimental metastasis of murine Lewis lung carcinoma cells.

The isolated laminin receptor (LN-R) labeled by 125I was reconstituted into liposomes. 125I-LN-R-liposomes and free 125I-LN-R were separated by Sepharose 4B column chromatography. The LN-R-liposomes showed affinity for laminin (LN) and were capable of binding to immobilized LN substrate. In order to make transplantation of LN-R, LN-R-liposomes were fused with cultured murine Lewis lung carcinoma cells with the help of polyethylene glycol (PEG) induction. The radiation with the fused cells was not removed by salt solution. The binding of the fused cells enriched in foreign LN-R to LN substrate increased by 87.5%. Furthermore, the murine Lewis lung carcinoma cells with and without transplanted LN-R were injected into C57BL/6J mice through tail veins (5 x 10(5) cells/each mouse) respectively. The mice in the test group died earlier than those in the control group. The total weight of lung tumor in the test group remarkably increased in comparison with those in the control group. The results taken together directly demonstrated that LN-R on carcinoma cell surface were involved in the recognition and binding of the cancer cells to LN in basement membranes, and also LN-R was of a crucial biological molecule in cancer metastasis.