Proteomics profiling identifies induction of caveolin-1 in chronic lymphocytic leukemia cells by bone marrow stromal cells.

Chronic lymphocytic leukemia (CLL) is an indolent B-cell malignancy in which cells reside in bone marrow, lymph nodes, and peripheral blood, each of which provides a unique microenvironment. Although the levels of certain proteins are reported to induce, changes in the CLL cell proteome in the presence of bone marrow stromal cells have not been elucidated. Reverse-phase protein array analysis of CLL cells before and 24 h after stromal cell interaction revealed changed levels of proteins that regulate cell cycle, gene transcription, and protein translation. The most hit with respect to both the extent of change in expression level and statistical significance was caveolin-1, which was confirmed with immunoblotting. Caveolin-1 mRNA levels were also upregulated in CLL cells after stromal cell interaction. The induction of caveolin-1 levels was rapid and occurred as early as 1 h. Studies to determine the significance of upregulated caveolin-1 levels in CLL lymphocytes are warranted.