Distinct hematopoietic support by two human stromal cell lines

Objective. The hematopoietic microenvironment is complex, and the role of m yofibroblast in its function is crucial. In order to obtain a stable model reflecting this particular cell type, we have previously established human bone marrow cell lines from primary myofibroblastic Strol(+) population (pS trol(+)). We placed HPV16 E6 and E7 expression under the control of differe nt promoters. Here, we have characterized and studied the hematopoietic sup port for two cell lines corresponding to the promoters alpha -SM (alpha SM- 56 line) and SV40 (SV40-56 line). Materials and Methods. The expression pro file was analyzed at the RNA level by gene array and at the protein level b y Western blot, flow cytometry, and ELISA, Hematopoietic support determined using colony-forming unit (CFU) and stroma-adherent colony-forming cell (S A-CFC) assays. Results. The phenotype of cell lines was not significantly m odified compared with primary myofibroblastic cells. They secreted a broad spectrum of hematopoietic cytokines and nonspecific mediators, The two Line s allowed the growth of hematopoietic precursors and had different support capabilities. Conclusions, We have extensively characterized two novel huma n bone marrow stromal cell lines. They retained a myofibroblastic phenotype and have substantial but different hematopoietic support capabilities. The se lines provided a basis for determining stromal factors involved in stem- tell regulation. (C) 2001 International Society for Experimental Hematology , Published by Elsevier Science Inc.