Superoxide dismutase activities of differentiating clones from an immortal cell line

Abstract

We have studied superoxide dismutase (SOD) levels in the X-REF-23 rat embryo fibroblast cell line. X-REF-23 is an immortal cell line that maintains a nontransformed phenotype throughout its known lifespan. Low-passage X-REF-23 cells undergo spontaneous differentiation into muscle and adipose cells, while high-passage X-REF-23 cells undergo little or no differentiation. SOD activities were measured in subclones of X-REF-23, which differentiate into muscle (AMC subclone) or adipose (AMB-J) cells, as well as the parental nondifferentiating X-REF-23 cells. Total SOD activity increased in all three cell lines with time in culture. Cu-ZnSOD was induced in the AMB-J and the X-REF-23 cells with time in culture, whereas the AMC cells showed no induction. MnSOD activity was induced during the time period in which differentiation occurred in the two differentiating clones. In contrast, MnSOD was not induced in this time period in the nondifferentiating X-REF-23 cell line. However, MnSOD activity was induced in the latter cell line at a much later time. Levels of immunoreactive MnSOD correlated quite well with MnSOD activity in all three cell lines. The nondifferentiating X-REF-23 cells, but not the two differentiating cells lines, showed a large increase in cell organelles with time in culture. In particular, an increase in very small mitochondria was observed; these mitochondria often showed evidence of disorganization.

Upregulation of manganese superoxide dismutase (SOD2) is a common pathway for neuroendocrine differentiation in prostate cancer cells

“…25 First evidences came from studies in immortal rat embryo fibroblasts that undergo spontaneous differentiation into muscle and adipose cells, process that is accompanied with a significant increase in MnSOD activity. 30 This phenomenon can be extended to some fungi in which MnSOD expression is also associated with both oval and falcate conidia differentiation. 31 All-trans retinoic acid has been shown to induce differentiation in neuroblastoma cells through the activation of NFjB, which in turn induces MnSOD expression.…”

Decrease in CuZn‐superoxide dismutase mRNA level during differentiation of human monocytic and promyelotic leukemia cells

“…The activity of CuZn-SOD is known to change during the process of differentiation. Recent findings indicate that this activity increases during differentiation of mouse erythroid leukemia cells [26] or during muscle and adipocyte differentiation of rat embryo cells [27]. CuZn-SOD activity is also known to increase during lung development [17] or oxidant stress [28].…”

All-trans-retinoic acid induces manganese superoxide dismutase in human neuroblastoma through NF-κB

“…Total SOD activity has been shown to increase as human monocytes differentiate in culture [22] and more specifically, while remaining low in nondifferentiating cells the activity of MnSOD increases as rat embryo fibroblasts differentiate into muscle or adipose cells [23]. Transfection with subsequent overexpression of human MnSOD into C3H10T1/2 and murine fibrosarcoma (FSa) cells enhanced differentiation into myoblasts upon treatment with 5-azacytidine [24][25].…”