Independent mutations in both alleles of the p53 tumor suppressor gene are a frequent finding in human T-cell
acute lymphoblastic leukemia (
T-ALL) cell lines and in the cells of some
T-ALL patients in relapse. One major goal of studying the status of p53 (and other tumor suppressor genes) in human
cancer is to facilitate the suppression of the tumorigenic phenotype through the restoration of the expression of the wild-type allele. While the efficient insertion of a suppressor into all cells of solid/metastatic human
tumors may at present be impossible, insertion into
leukemia cells may be feasible due to the accessibility of the
leukemia cells in the body. To examine the feasibility of suppressing the tumorigenicity of human T-
leukemia cells, the human
T-ALL cell line Be-13, which lacks endogenous p53
protein, was infected with a recombinant retrovirus encoding the wild-type allele of human p53 (hwtp53). Expression of p53 reduced the growth rate of infected Be-13 cells in vitro, suppressed colony formation in
methylcellulose cultures, and abrogated their tumorigenic phenotype in nude mice in vivo. These results suggest that suppression of the leukemic phenotype of relapse
T-ALL-derived Be-13 cells is feasible. Acute
leukemia cell suppression via high-efficiency
infection with retroviruses encoding wtp53 may be feasible and beneficial in
T-ALL cases as part of a
bone marrow transplantation regimen in an effort to reduce the frequency of posttransplantation relapse.