Establishment and characterization of a new murine cell line (SR-4987) derived from marrow stromal cells

A new murine cell line designated as SR-4987 was established by treating a long-term bone marrow culture with the supernatant from Y-1 cells which actively produce viral C-particles (MuLV). The line showed a fibrolbast-like morphology and its mesodermal origin was confirmed by immunocytochemical staining. Flow cytometric analysis of DNA index evidenced a tetraploid number of chromosomes whereas cell cycle analysis showed 34.8% of cells in S phase and 60.7% in G1.In vitro growth studies demonstrated a population doubling time of 14.7h, a good plating efficiency (52.3%) and a very poor agar clonogenic capacity (0.6%). SR-4987 was tumorigenic only in syngeneic mice in which sarcomas were induced. The line produced M-CSF in the culture supermatant whereas G-CSF, IL-3 and GM-CSF were not detected. Studies are in progress to assess the production of other cytokines and to verify if same autocrine growth factor is involved in the control of SR-4987 proliferation. Our line provides a further model of stromal cells for studying the interaction between hemopoietic progenitors and their micro-environment, as well as to study factors produced by stromal cells acting as modulators of proliferation and differentiation of related cell populations.