Manipulating the onset of cell cycle withdrawal in differentiated erythroid cells with cyclin-dependent kinases and inhibitors

Abstract

Terminal differentiation of erythroid cells results in terminal cell divisions followed by irreversible cell cycle withdrawal of hemoglobinized cells. The mechanisms leading to cell cycle withdrawal were assessed in stable transfectants of murine erythroleukemia cells, in which the activities of cyclin-dependent kinases (CDKs) and CDK inhibitors (CDKIs) could be tightly regulated during differentiation. Cell cycle withdrawal of differentiating cells is mediated by induction of several CDKIs, thereby leading to inhibition of CDK2 and CDK4. Manipulation of CDK activity in differentiating cells demonstrates that the onset of cell cycle withdrawal can be either greatly accelerated or greatly delayed without affecting hemoglobin levels. Extending the proliferation of differentiating cells requires the synergistic action of CDK2 and CDK4. Importantly, CDK6 cannot substitute for CDK4 in this role, which demonstrates that the 2 cyclin D–dependent kinases are functionally different. The results show that differentiating hemoglobinized cells can be made to proliferate far beyond their normal capacity to divide.

The histone methyltransferase inhibitor A-366 enhances hemoglobin expression in erythroleukemia cells upon co‐exposure with chemical inducers in culture

“…Notably, CDK6 was significantly downregulated (approximately at 50% of the initial levels) consistent with previous studies connecting CDK6 reduction with differentiation (Fig. 5 ) [ 31 , 32 , 39 , 40 ]. On the contrary, A-366 merely impacts the effectors of apoptosis, as the expression levels of caspase 3, caspase 8, caspase 9, Bcl-2 and Bax remain almost unchanged (Fig.…”

Genetic manipulation of RPS5 gene expression modulates the initiation of commitment of MEL cells to erythroid maturation: Implications in understanding ribosomopathies

“…2J). The expression profile of CDks detected at late stages of differentiating MEL cells coincide with previous observations (22,(25)(26)(27)(28).…”

“…Initiation of MEL cell differentiation has been reported to occur within the G 1 /S interphase and that terminal erythroid cell maturation is associated with G 0 /G 1 cell cycle arrest and the coordinated function of CDk2, CDk4 and CDk6 along with their inhibitors (CDkIs) (13,14,(25)(26)(27)(28). As reported earlier, MEL-C14 cells delayed the initiation of the onset of differentiation upon exposure to chemical inducers, whereas at the same time a slower entrance of cells in G 0 /G 1 phase and significant changes in the profile of CDK2, CDK4 and CDK6 have been recorded (22).…”

A Genetic Strategy for Single and Combinatorial Analysis of miRNA Function in Mammalian Hematopoietic Stem Cells

“…Further studies are needed to examine whether either or both miRNAs of the cluster promote survival, maintenance, or proliferation of erythroid cells under steady‐state or stress erythropoiesis conditions. A link between cell cycle withdrawal and differentiation has been repeatedly demonstrated in several cellular systems, including erythroid maturation [44–47]. GATA‐1, a key transcription factor in erythroid development, has been shown to promote both erythroid maturation and G 1 arrest through upregulation of cyclin‐dependent kinase (Cdk) inhibitors p18 INK4C and p27 Kip1 and inhibition of cyclin D2 and G 1 Cdks [47].…”