INTEGRINS AND LAMININS IN HUMAN RENAL-CARCINOMA CELLS AND TUMORS GROWN IN NUDE-MICE

We studied by indirect immunofluorescence microscopy the distribution of integrins and laminins in four human renal cell carcinoma cell line s (CAKI-2, A498, CAKI-1, and ACHN) in vitro and in s.c. xenografts in nude mice. In vitro, all four cell lines expressed the alpha(1), alpha (3), alpha(nu), beta(1), beta(3), and beta(5) subunits and three expre ssed the alpha(6) subunit; all cell lines expressed laminin A, B1, and B2 chains. Histologically, the CAKI-2 and A498 cells formed different iated grade 1 (G1) and G2 tumors, respectively, while the CAKI-1 and A CHN cells formed poorly differentiated G3 tumors. The described integr in profile was largely retained upon xenografting. Basal polarization of the alpha(3) and alpha(6) integrin subunits was found in the differ entiated tumors, and human laminins were detected as discrete linear s tructures surrounding tumor cell clusters in these tumors, suggesting that the cells have retained a polarized cell-laminin interaction char acteristic of normal tubular epithelial cells. A disorganized distribu tion of integrins and laminins was noted in the G3 tumors. We conclude that these renal carcinoma cell lines displayed an integrin repertoir e similar to that of clinical renal carcinomas and retained it upon xe nografting. Furthermore, the organization of integrins and laminins in the xenografts correlated with histological grade.