Factor-dependent human leukemia cell lines: new models for regulation of acute non-lymphocytic leukemia cell growth and differentiation.

Human acute non-lymphocytic leukemia (ANLL) cell lines have been valuable models for studying leukemic transformation and mechanisms regulating blood cell growth and differentiation. Until recently, all human leukemia lines were grown in fetal bovine serum and were not dependent on exogenous hemopoietic growth factors. Since most primary human ANLL cells require growth factors for in vitro cell growth, the behavior of growth factor-independent cells may not be representative of most acute leukemias. Recently, factor-dependent cell lines were established from patients with acute leukemias which are absolutely dependent on growth factors for in vitro proliferation and survival. These cells were derived from different primary leukemia phenotypes, and exhibit heterogeneous growth and differentiation responses. Like the murine growth factor-dependent cell lines which preceded them, these new human lines are important models for growth factor signal transduction as well as proliferative responses and differentiation. Factor-dependent human cell lines have already provided important insights into potential mechanisms of human blood cell transformation, and identification of cellular and genetic abnormalities responsible for the leukemia phenotype.