CDK4/Cyclin D1/PCNA Complexes during Staurosporine-Induced G1 Arrest and G0 Arrest of Human Fibroblasts

Gadbois, Donna M.; Peterson, Scott; Bradbury, E. Morton; Lehnert, Bruce E.

doi:10.1006/excr.1995.1309

Cited by 19 publications

(13 citation statements)

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“…As G 1 arrested cells express PCNA (Gadbois et al, 1995;Zölzer et al, 1994), this may generate the appearance of PCNA immunoreactive cells without producing an increase in the number of S-phase cells (McCormick and Hall, 1992). In the present study, proliferation of microglia/macrophages has been established by both expression of PCNA and actual increases in cell numbers, but we can not discard the possibility that some activated microglia/macrophages could enter the cell cycle and express PCNA without undergoing cell division.…”

Section: Proliferative Origin and Fate Of Microgliamentioning

confidence: 53%

“…It is known that some cells may become activated and enter the cell cycle but rest quiescent in G 1 since some factors are required for progression from G 1 to S (Avanzi et al, 1991;Gadbois et al, 1995). As G 1 arrested cells express PCNA (Gadbois et al, 1995;Zölzer et al, 1994), this may generate the appearance of PCNA immunoreactive cells without producing an increase in the number of S-phase cells (McCormick and Hall, 1992).…”

Section: Proliferative Origin and Fate Of Microgliamentioning

confidence: 99%

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Time Course of Proliferation and Elimination of Microglia/Macrophages in Different Neurodegenerative Conditions

Vela

Yáñez

González

et al. 2002

Journal of Neurotrauma

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Ablation of the hindlimb area of the sensorimotor cortex produces degeneration in the cortex (invasive traumatic injury) and leads to retrograde and/or anterograde degeneration in the thalamus (non-invasive injury, distal reaction). This provides an useful model to study the proliferation and elimination of microglia/macrophages in different neurodegenerative conditions. Changes in the morphology, distribution and numbers of microglia in the affected cortex and thalamus were analyzed at various time points (12 h to 30 days) after injury. In parallel, proliferation was determined by immunocytochemistry for the proliferating cell nuclear antigen and cell death by the TUNEL method. Proliferation was an early event in the microglia/macrophage response (from 12 h in the cortex and from 2 days post-lesion in the thalamus) and persisted up to 30 days. The different microglia/macrophage phenotypes proliferated in a specific temporospatial pattern. In the lesioned cortex, early activation and proliferation of intrinsic microglia was accompanied, from the second post-lesion day, by monocyte entrance and proliferation of monocyte-derived cells. In contrast, accumulation of cells in the thalamus resulted from proliferation of intrinsic microglia, without apparent/significant monocytic recruitment. During the subsequent microglia/macrophages removal the majority of the cells in the cortex transformed into ameboid cells devoid of cell processes that progressively accumulated as fully-developed macrophages tissue within the lesion (3-14 days) ultimately migrating out to the meningeal connective tissue (14-30 days). Only some process-bearing cells, remaining in the cortical tissue bordering the lesion, underwent degeneration by 14-21 days post-lesion. In contrast, in the distal affected thalamic nuclei, microglial cell death occurred by 14-30 days post-lesion. Altogether, this study shows that both the origin and fate of microglia/ macrophages depend on the nature of the lesion.

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Section: Proliferative Origin and Fate Of Microgliamentioning

confidence: 53%

Section: Proliferative Origin and Fate Of Microgliamentioning

confidence: 99%

Time Course of Proliferation and Elimination of Microglia/Macrophages in Different Neurodegenerative Conditions

Vela

Yáñez

González

et al. 2002

Journal of Neurotrauma

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“…Staurosporine inhibits the activity of purified cdc2 kinase with an IC50 value of 4-5 nM (Gadbois et al, 1992) and, hence, could block the cell cycle through this effect on a cell cycle kinase. Alternatively, Gadbois et al (1995) have suggested that staurosporine inhibits a CDK activating kinase (CAK) in human skin fibroblasts.…”

Section: Introductionmentioning

confidence: 98%

Different mechanisms for inhibition of cell proliferation via cell cycle proteins in PC12 cells by nerve growth factor and staurosporine

Gollapudi

Neet

1997

J. Neurosci. Res.

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PC12 cells have previously been shown to cease cell division during nerve growth-factor (NGF)-induced differentiation by affecting specific cell cycle proteins. Staurosporine, a protein kinase inhibitor, also causes PC12 cell differentiation, independently of neurotrophins or plasma membrane receptors. We have investigated the relationship of the tumor suppressor protein, p53, and other cell cycle proteins to the antiproliferative effects of NGF and staurosporine in PC12 cells. NGF treatment of PC12 cells stimulated an increase of p53 protein in the nucleus and, more slowly, an increase in total cellular p53 protein. Levels of the cyclin-kinase inhibitor p21/WAF1, cyclin D1, and cyclin G, all downstream transcriptional targets of p53, increased after short times of NGF treatment. Cessation of replication and differentiation occurred more rapidly in defined medium (2 days) than in serum medium (6 days), in correspondence with the more rapid changes in both p53 and p21/WAF1 levels in defined medium (1 hour) than in serum (1 day). Levels of p34cdc2 and p33cdk2 kinase dropped after 6 to 10 days treatment with NGF in serum, close to the time of terminal differentiation. Staurosporine, on the other hand, inhibited DNA replication of PC12 cells in a time- and dose-dependent fashion by affecting cyclin-dependent kinases. Staurosporine had no effect on the protein levels of p53, p21/WAF1, or cyclin G. The kinase activity of both p34cdc2 and p33cdk2 were inhibited in vitro with IC50 values of 20 nM and 75 nM, respectively. In vivo p34cdc2 kinase activity was inhibited within 1 day, before the decrease in the levels of p34cdc2 protein at days 2 to 3. In contrast, in vivo p33cdk2 kinase activity only decreased in concert with protein levels. Although both NGF and staurosporine inhibit DNA replication concomitant with induction of differentiation by affecting the activity of p34cdc2 and p33cdk2, the mechanism of the two agents is quite different. NGF achieves inhibition of activity of these cyclin-dependent kinases by signalling through the TrkA receptor to the tumor suppressor protein p53 and then to p21/WAF1. In contrast, staurosporine directly inhibits the activity of p34cdc2 and p33cdk2 by binding to them and also indirectly by alteration of their phosphorylation through other regulatory kinases.

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“…The mechanism underlying the differential effects of staurosporine on the pRb pathway of normal and tumor cells remains unknown. Some have suggested that the effects of staurosporine on the cell cycle are mediated by a number of cell cycle regulators including cyclin E, cyclin D1, CDK2, p18, p21, and p27 (11,12,(17)(18)(19)(20)(21)(22). To further examine the mechanism for the differences in staurosporine action between normal and tumor cells, we developed an in vitro model consisting of cell lines with different pRb status.…”

Section: Introductionmentioning

confidence: 99%

The Differential Staurosporine-Mediated G1 Arrest in Normal versus Tumor Cells Is Dependent on the Retinoblastoma Protein

McGahren-Murray¹,

Terry²,

Keyomarsi³

2006

Cancer Research

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Previously, we reported that breast cancer cells with retinoblastoma (pRb) pathway-defective checkpoints can be specifically targeted with chemotherapeutic agents, following staurosporine-mediated reversible growth inhibition in normal cells. Here we set out to determine if the kinetics of staurosporine-mediated growth inhibition is specifically targeted to the G 1 phase of cells, and if such G 1 arrest requires the activity of wild-type pRb. Normal human mammary epithelial and immortalized cells with intact pRb treated with low concentrations of staurosporine arrested in the G 1 phase of the cell cycle, whereas pRb-defective cells showed no response. The duration of G 1 and transition from G 1 to S phase entry were modulated by staurosporine in Rb-intact cells. In pRb + cells, but not in Rb À cells, low concentrations of staurosporine also resulted in a significant decrease in cyclin-dependent kinase 4 (CDK4) expression and activity. To directly assess the role of pRb in staurosporine-mediated G 1 arrest, we subjected wild-type (Rb +/+ ) and pRb À/À mouse embryo fibroblasts (MEFs) to staurosporine treatments. Our results show that whereas Rb +/+ MEFs were particularly sensitive to G 1 arrest mediated by staurosporine, pRb À/À cells were refractory to such treatment. Additionally, CDK4 expression was also inhibited in response to staurosporine only in Rb +/+ MEFs. These results were recapitulated in breast cancer cells treated with siRNA to pRb to down-regulate the pRb expression. Collectively, our data suggest that treatment of cells with nanomolar concentrations of staurosporine resulted in downregulation of CDK4, which ultimately leads to G 1 arrest in normal human mammary epithelial and immortalized cells with an intact pRb pathway, but not in pRb-null/defective cells.

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CDK4/Cyclin D1/PCNA Complexes during Staurosporine-Induced G1 Arrest and G0 Arrest of Human Fibroblasts

Cited by 19 publications

References 0 publications

Time Course of Proliferation and Elimination of Microglia/Macrophages in Different Neurodegenerative Conditions

Time Course of Proliferation and Elimination of Microglia/Macrophages in Different Neurodegenerative Conditions

Different mechanisms for inhibition of cell proliferation via cell cycle proteins in PC12 cells by nerve growth factor and staurosporine

The Differential Staurosporine-Mediated G1 Arrest in Normal versus Tumor Cells Is Dependent on the Retinoblastoma Protein

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