The stability of kidney-induced selection of Lewis lung tumor cell populations, and their metastasis-related behavior.

The surface charge densities of Lewis lung carcinoma (3LL) cells were measured in tumors transplanted into subcutaneous (s.c.) sites, and into the kidneys (K), as well as in kidney tumors transplanted to, and maintained in, the s.c. site (K.s.c.). K cells showed a significant increase in net negativity in comparison with s.c. cells, which was stable over II passages. On back-transplantation of K cells to the s.c. site, the net negativity of K.s.c. cells was higher than that of the s.c. cells, but the increase was stable for only 7 passages; on subsequent passages the net negativity fell, approaching that of the s.c. cells. Detailed analyses suggest the presence in these tumors of 2 subpopulations of 3LL cells, whose proportions change in the different sites studied to produce changes in the mean electrophoretic mobilities of the whole cancer cell populations. The altered proportions of the 2 cell types in the 3 sites were not associated with major changes either in their general behavior with respect to metastasis, or in differential growth in various organs following s.c., tail vein, and left ventricular injections. Selection induced by growth in the kidney, as evidenced by physiochemical changes at the cancer cell surface, was not associated with kidney preference in metastasis or metastasis-related behavior.