Growth Inhibition of B-cell Precursor Acute Lymphoblastic Leukemia Cell Lines by Monocytes: a Role for Prostaglandin E2

Leukemic cell lines have proven invaluable in the molecular analysis of recurring chromosomal translocations but the optimal methods for leukemia cell line establishment are unknown. During in vitro culture, most B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cells die within 1 week at least partially mediated by inhibitors elaborated by peripheral blood mononuclear cells (PB MNCs) present within the leukemia sample. In experiments reported here, cyclooxygenase inhibitors (indomethacin and meclofenamic acid) blocked the PB MNC-mediated inhibition of BCP-ALL proliferation. Also, prostaglandin E2 (PGE2) was detected in supernatants from PB MNC cultures. When PGE2 was mixed directly with BCP-ALL cells, proliferation decreased significantly. Under the culture conditions used, PB MNCs secreted PGE2 which appears to be one of the major inhibitors of BCP-ALL growth in vitro.