EXPRESSION OF CADHERIN-CATENIN COMPLEXES IN HUMAN LEUKEMIA-CELL LINES

Cadherins are Ca2+-dependent cell-cell adhesion molecules, and are inv olved in the formation and maintenance of the histo-architecture. Usin g cultured human leukemia cell lines (adult T cell leukemia and thymus -derived lymphoma cell lines), we obtained evidence that cadherins and catenins are expressed in these cell lines but not in normal leukocyt es, Immunoblot analysis of cells using a pan-cadherin serum, directed against the conserved carboxyl-terminus of cadherins, revealed a major band of 130 kDa and a minor one of 135 kDa, The 130 kDa cadherin was also recognized by anti-N-cadherin antibodies, A human N-cadherin cDNA probe hybridized to a 4.3 kb mRNA isolated from cells immunologically positive for N-cadherin, Sequencing of the cDNA fragments isolated fr om the cells revealed a N-cadherin sequence, Cell surface expression o f N-cadherin was confirmed by indirect immunofluorescence staining of the cells, Immunoblot and Northern blot analyses also revealed the pre sence of alpha-catenin, beta-catenin, and gamma-catenin (plakoglobin) in these cell lines, Immunoprecipitation with anti-N-cadherin antibodi es and subsequent immunoblot analysis with anti-catenin antibodies rev ealed that N-cadherin is associated with alpha- and beta-catenins, a p rerequisite for cadherins to be functional, These results suggest an i mportant role of the cadherin-catenin complexes in the behavior of the leukemia cells.