Responsiveness of the in vitro hematopoietic microenvironment to platelet-derived growth factor.

The adherent or stromal cells in human long-term marrow cultures, a possible in vitro counterpart of the in vivo microenvironment, were investigated for responsiveness to platelet-derived growth factor (PDGF). Many stromal cells from cultures derived from normal donors as well as from patients with chronic myelogenous leukemia, bore receptors to PDGF and were stimulated to incorporate [3H]-thymidine by highly purified PDGF and to a lesser extent by epidermal growth factor (EGF). These data suggest that PDGF and perhaps EGF may be involved in the regulation of the in vitro microenvironment and, therefore, of normal and possibly neoplastic hematopoiesis.