GROWTH AND DIFFERENTIATION OF BONE-MARROW HEMATOPOIETIC-CELLS IN MICEBEARING EHRLICH ASCITE TUMOR AND TREATED WITH DICYCLOPENTADIENILDICHIOROTITANIUM (IV)

In this work we have:investigated the growth and differentiation of bo ne marrow stem cells in mice bearing Ehrlich ascites tumor-and treated with three dose-regimens of Dicyclopentadienyldichlorotitanium (IV) ( DDCT). We also: studied the presence Of colony stimulating factors In the serum of PDCT-treated animals as well-as the effects-of the drug o n the survival of the tumor-bearing mice. The-results demonstrated tha t the myelosuppression developed in the tumor-bearing animals is preve nted by the administration:of 1, 2 or 3 doses of 15 mg/kg DDCT. In the treatment with three doses, however, 23 % of the animals died. Moreov er, DDCT treatment in normal animals resulted in increased numbers of CFU-GM. We observed the presence of stimulating factors in the serum o f drug-treated animals which induced the growth and differentiation of bone marrow progenitor cells from normal animals in vitro. On the oth er hand, in vitro addition of the drug to these cultures had no effect . Thus, we conclude that the drug protects against the myelosuppressio n induced by the tumor and that this protection may be related to an i ndirect action of the drug. (C) 1998 International Society for Immunop harmacology. Published by Elsevier Science Ltd.