Alterations in electrophoretic mobility, diaphorase activity, and terminal differentiation induced in murine erythroleukemia lines by differentiating agents

Abstract

The electrophoretic mobilities (EPMs) and semiquinone reductase activities of two clones of Friend murine erythroleukemia (MEL) cells were investigated as a function of treatment with the inducing agents dimethylsulfoxide (DMSO) and hexamethylene bisacetamide (HMBA). As reported previously by others, the inducible clone DS19 lost its ability to grow in soft agar and expressed hemoglobin as judged by benzidine/H2O2 staining after 96 hours of treatment with 1% DMSO or 4 mM HMBA. In addition, its EPM fell by 14%, its semiquinone reductase activity by 40%, and its mean diameter by 10%. The second clone, R1, retained its ability to grow in soft agar and lacked hemoglobin expression after treatment with HMBA and DMSO, characterizing it as noninducible. However, R1 did demonstrate alterations in EPM, semiquinone reductase activity, and cell diameter that closely paralleled those found in DS19. Such responses were not seen in three non-MEL cell lines exposed to HMBA or DMSO, suggesting that clone R1 responded to these inducing agents in a cell-line specific manner but that its ability to complete the sequences necessary for differentiation may be blocked at an unknown point distal to the block characteristic of untreated cells. The data show that while a reduction in EPM, semiquinone reductase activity, and cell diameter accompany induced differentiation in MEL cells, such changes can occur in the absence of a commitment to terminal differentiation.

Intra and extracellular surface charges near Ca2+ channels in neurons and neuroblastoma cells

“…This study was extended to a murine neuroblastoma cell line (Nl cells) bearing LVA Ca2l channels, to com- pare the results of our approach to the available studies, Solutions attributing a higher surface charge to malignant as compared to normal cells (Adam and Adam, 1975;Elul et For experiments in the presence of Brown et al, 1979;Pretlow and Pretlow, 1979;extracellular divalent cations al., 1975extracellular divalent cations al., 'Brown et al, 1979Pretlow and Pretlow, 1979; Extracellular solution for experiments with neurons contained (mM): Price et al, 1987;Gascoyne and Becker, 1990).…”

Dielectrophoretic-Field Flow Fractionation Analysis of Dielectric, Density, and Deformability Characteristics of Cells and Particles

“…To test the theory and demonstrate isolation of particle parameters from elution data, experiments were conducted using DS19 erythroleukemia cells61. These were convenient because their growth in suspension culture allowed a fresh aliquot to be used for every run, ensuring consistency.…”