Ba. Roecklein et B. Torokstorb, FUNCTIONALLY DISTINCT HUMAN MARROW STROMAL CELL-LINES IMMORTALIZED BYTRANSDUCTION WITH THE HUMAN PAPILLOMA-VIRUS E6 E7 GENES/, Blood, 85(4), 1995, pp. 997-1005
A replication-defective recombinant retrovirus containing the human pa
pilloma virus E6/E7 genes (LXSN-16 E6E7) was used to immortalize strom
al cells from human marrow. The E6/E7 gene products interfere with the
function of tumor-suppressor proteins p53 and Rb, respectively, there
by preventing cell cycle arrest without causing significant transforma
tion. Twenty-seven immortalized clones designated HS-1 to HS-27 were i
solated, four of which are characterized in this report. Two cell line
s, HS-5 and HS-21, appear to be fibroblastoid and secrete significant
levels of granulocyte colony-stimulating factor (G-CSF), granulocyte-m
acrophage-CSF (GM-CSF), macrophage-CSF (M-CSF), Kit ligand (KL), macro
phage-inhibitory protein-1 alpha, interleukin-6 (IL-6), IL-8, and IL-1
1. However, only HS-5 supports proliferation of hematopoietic progenit
or cells when cocultured in serum-deprived media with no exogenous fac
tors. Conditioned media (CM) from HS-5 promotes growth of myeloid colo
nies to significantly greater extent than a cocktail of recombinant fa
ctors containing 10 ng/mL of IL-1, IL-3, IL-6, G-CSF, GM-CSF, and KL a
nd 3 U of erythropoietin (Epo). Two additional clones, HS-23 and HS-27
, resemble ''blanket'' cells, with an epithelioid morphology, and are
much larger, broader, and flatter when compared with HS-5 and HS-21. T
hese lines secrete low levels of growth factors and do not support pro
liferation of isolated progenitor cells in cocultures. CM from HS-23 a
nd HS-27 also fail to support growth of myeloid colonies. Both HS-23 a
nd HS-27 express relatively high levels of VCAM-1, yet HS-27 is the on
ly line that supports the formation of ''cobblestone'' areas by isolat
ed CD34(+)38(lo) cells. We hypothesize that HS-5, HS-21, HS-23, and HS
-27 represent functionally distinct components of the marrow microenvi
ronment. (C) 1995 by The American Society of Hematology.