Pr. Muller et al., NUCLEAR LAMIN EXPRESSION REVEALS A SURPRISINGLY HIGH GROWTH FRACTION IN CHILDHOOD ACUTE LYMPHOBLASTIC-LEUKEMIA CELLS, Leukemia, 8(6), 1994, pp. 940-945
In an attempt to better characterize leukemic bone marrow cells of chi
ldren with ALL in G(0)/G(1), we studied the variation of the nuclear p
rojection area (NPA) during the cell cycle. Approximately half of the
increase of the nuclear volume during the cell cycle occurred before D
NA synthesis. Next, we assessed by in situ hybridization (ISH) the exp
ression of nuclear envelope type A/C and type B lamins in leukemic lym
phoblast and unstimulated as well as stimulated normal peripheral bloo
d mononuclear cells (PBMC). It was found that 82.0+/-16.0% of the ALL
cells expressed B-type and 5.8+/-3.1% A/C-type lamins. The in vitro (3
)HdT pulse-labeling index ((3)HdT LI) of ALL cells varied from 1.3 to
16.8%. Of unstimulated PBMC 2.9 and 1.2% expressed lamin type B and A/
C, respectively. The (3)HdT LI was 0.8%. In conA-stimulated PBMC, the
corresponding values were 95.3 and 74.8% and 31.0%, respectively. In v
iew of the current concepts regarding G(1) events and regulation of ce
ll proliferation, we considered B-type lamin expression an early marke
r for the commitment to proliferation and used it for growth fraction
(GF) determinations. By this method, a surprisingly high GF was found
in ALL cell populations; there was no correlation between GF and the (
3)HdT LI, as seen in normal cells.