scholarly journals The cyclin-dependent kinase inhibitors, cki-1 and cki-2, act in overlapping but distinct pathways to control cell-cycle quiescence duringC. elegansdevelopment

Cell Cycle ◽  
2009 ◽  
Vol 8 (16) ◽  
pp. 2613-2620 ◽  
Author(s):  
Sarah H. Buck ◽  
Daniel Chiu ◽  
R. Mako Saito
Keyword(s):  
Cell Cycle ◽  
Kinase Inhibitors ◽  
Control Cell ◽  
Cyclin Dependent Kinase

The Cyclin-Dependent Kinase Inhibitors p19Ink4d and p27Kip1 Are Coexpressed in Select Retinal Cells and Act Cooperatively to Control Cell Cycle Exit

2002 ◽  
Vol 19 (3) ◽  
pp. 359-374 ◽  
Author(s):  
Justine J. Cunningham ◽  
Edward M. Levine ◽  
Frederique Zindy ◽  
Olga Goloubeva ◽  
Martine F. Roussel ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Kinase Inhibitors ◽  
Control Cell ◽  
Cyclin Dependent Kinase ◽  
Cell Cycle Exit ◽  
Retinal Cells

Synthesis and anticancer activity of some pyrido[2,3-d]pyrimidine derivatives as apoptosis inducers and cyclin-dependent kinase inhibitors

2019 ◽  
Vol 11 (18) ◽  
pp. 2395-2414 ◽  
Author(s):  
Safinaz E-S Abbas ◽  
Riham F George ◽  
Eman M Samir ◽  
Mostafa MA Aref ◽  
Hatem A Abdel-Aziz
Keyword(s):  
Cell Cycle ◽  
Anticancer Agents ◽  
Kinase Inhibitors ◽  
Cytotoxic Agents ◽  
Cyclin Dependent Kinase ◽  
Apoptosis Induction ◽  
Pyrimidine Derivatives ◽  
Induced Apoptosis ◽  
Emergence Of Resistance ◽  
Mcf 7

Aim: Due to emergence of resistance to available anticancer agents, there is a need to search for new cytotoxic agents. Methods: Pyrido[2,3- d]pyrimidines (4–6) and their tricyclic derivatives (7–13) were prepared and screened for their cytotoxicity against breast MCF-7, prostate PC-3 and lung A-549 cancer cell lines as well as normal fibroblasts WI-38. Results: The most active compounds were 6b, 6e and 8d compared with doxorubicin. Moreover, compounds 6b and 8d induced apoptosis in PC-3 and MCF-7, respectively via activation of CASP3 (in PC-3 only), Bax, p53 and down regulation of Bcl2 in addition to CDK4/6 inhibition. Conclusion: Pyrido[2,3- d]pyrimidine represents an important core for discovery of new potent cytotoxic agents acting on the cell cycle via apoptosis induction through either intrinsic or extrinsic pathways.

scholarly journals Expression and modulation of p42/p44 MAPKs and cell cycle regulatory proteins in rat pancreas regeneration

1999 ◽  
Vol 277 (5) ◽  
pp. G953-G959 ◽  
Author(s):  
Jean Morisset ◽  
JoséCristobal Aliaga ◽  
Ezéquiel L. Calvo ◽  
Judith Bourassa ◽  
Nathalie Rivard
Keyword(s):  
Cell Cycle ◽  
Molecular Mechanisms ◽  
Kinase Inhibitors ◽  
Regulatory Proteins ◽  
Mitogen Activated Protein Kinase ◽  
Cyclin Dependent Kinase ◽  
Mapk Activation ◽  
Pancreas Regeneration ◽  
Mitogen Activated Protein ◽  
Cell Cycle Regulatory Proteins

Pancreatic growth occurs after CCK, CCK-induced pancreatitis, and pancreatectomy; the mechanisms involved remain unknown. This study evaluates mitogen-activated protein kinase (MAPK) activation and expression of cell cycle regulatory proteins after pancreatectomy to understand the cellular and molecular mechanisms involved in pancreas regeneration. Rats were killed 1–12 days after pancreatectomy, and p42/p44 MAPK activation, expression of the cyclins D and E, cyclin-dependent kinase (Cdk)-2 activity, retinoblastoma protein (pRb) hyperphosphorylation, and expression of the cyclin kinase inhibitors p15, p21, and p27 were examined. Pancreatic remnants exhibited sustained p42/p44 MAPK activation within 8 h. Cyclins D1 and E showed maximal expression after 2 and 6 days, coinciding with maximal hyperphosphorylation of pRb and Cdk2 activity. The expression of p15 vanished after 12 h, p27 disappeared gradually, and p21 increased early. The p27 complexed with Cdk2 dissociated after 2 days, whereas p21 associated in a reverse fashion. In conclusion, sustained activation of p42/p44 MAPKs and Cdk2 along with overexpression of cyclins D1 and E and reduction of p15 and p27 cyclin inhibitors occurred early after pancreatectomy and are active factors involved in signaling that leads to pancreas regeneration.

scholarly journals Vinblastine sensitizes leukemia cells to cyclin-dependent kinase inhibitors, inducing acute cell cycle phase-independent apoptosis

2011 ◽  
Vol 12 (4) ◽  
pp. 314-325 ◽  
Author(s):  
Darcy J.P. Bates ◽  
Bethany L. Salerni ◽  
Christopher H. Lowrey ◽  
Alan Eastman
Keyword(s):  
Cell Cycle ◽  
Kinase Inhibitors ◽  
Cell Cycle Phase ◽  
Leukemia Cells ◽  
Cycle Phase ◽  
Cyclin Dependent Kinase

STI571 Suppresses Proliferation by Restoring Nuclear Cyclin Dependent Kinase Inhibitors (CDKIs) while STI571+TRAIL Promotes Cell Death by Decreasing Cytoplasmic CDKIs.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1992-1992
Author(s):  
Mo A. Dao ◽  
Catherine M. Verfaillie
Keyword(s):  
Cell Cycle ◽  
Cell Death ◽  
Myeloid Leukemia ◽  
Kinase Inhibitors ◽  
Hematopoietic Cells ◽  
Cyclin Dependent Kinase ◽  
The Past ◽  
Cell Cycle Inhibitors ◽  
Nuclear Cell ◽  
Resistant Cells

Abstract Cyclin dependent kinase inhibitors (CDKIs), p27Kip1 and p21Cip1, function as cell cycle inhibitors when located in the nucleus. When localized to the cytoplasm, these CDKIs can function as anti-apoptotic molecules by sequestering/preventing the activation of pro-apoptotic proteins such as ASK1 and procaspase-3. Our lab has reported elevated cytoplasmic CDKIs and decreased nuclear CDKIs in hematopoietic cells expressing BCR/ABL, the oncogene found in more than 90% of cases of chronic myeloid leukemia. Within the past decade, STI571 has been shown highly promising for CML treatment. However, there is increasing evidence suggesting that the drug might function more as a suppressor of proliferation and less as a promoter of cell death. In the current studies, we differentiate the effect of STI571 on proliferation vs. survival by tracking the subcellular increase/decrease in CDKIs using MO7e cells engineered to express BCR/ABL. To determine if a correlation exists between STI571 resistance and levels of cytoplasmic anti-apoptotic CDKIs, we also investigated changes in levels of nuclear vs. cytoplasmic CDKIs in LAMA84 -S (sensitive to STI571) vs. LAMA84-R (resistant to STI571). And lastly, we tested whether activation of TRAIL would enhance cell death in STI571-resistant cells. STI571 treatment increases nuclear CDKIs, correlating directly with a decrease in proliferation of MO7e/p210 cells. However, the high levels of cytoplasmic CDKIs in MO7e/p210bcr/abl was not modulated following STI571 treatment and cell death was not prominent, unless growth factors were removed. Moreover, cytoplasmic p21Cip co-immunoprecipitated with ASK1 and procaspase 3. When compared with LAMA-S cells, LAMA-R cells expressed even higher levels of cytoplasmic CDKIs. Treatment with STI571 decreased cytoplasmic CDKIs in LAMA84-S cells and resulted in cell death. As hypothesized, LAMA84-R cells did not show reduction in cytoplasmic CDKIs and did not enter apoptosis. However, when treated with STI571 and TRAIL, LAMA84-R cells showed a decrease in cytoplasmic CDKIs, and increase in apoptosis. Based on these observations, we conclude that: 1. BCR/ABL expression reduces nuclear CDKIs but increases cytoplasmic CDKIs. 2. STI571 treatment restores nuclear CDKIs and reduces cell proliferation of BCR/ABL expressing cells under physiological conditions. 3. Treatment of STI571+TRAIL reduces cytoplasmic CDKIs and increases cell death of BCR/ABL expressing cells, most notably, the STI571-resistant cells. In conclusion, we show that the imbalance between nuclear (cell cycle inhibitor) and cytoplasmic (cell survival enhancer) CDKIs exist in BCR/ABL-hematopoietic cells.

scholarly journals Reversal of Growth Suppression by p107 via Direct Phosphorylation by Cyclin D1/Cyclin-Dependent Kinase 4

2002 ◽  
Vol 22 (7) ◽  
pp. 2242-2254 ◽  
Author(s):  
Xiaohong Leng ◽  
Martin Noble ◽  
Peter D. Adams ◽  
Jun Qin ◽  
J. Wade Harper
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Control Cell ◽  
Growth Suppression ◽  
Cyclin Dependent Kinase ◽  
Culture Cells ◽  
Cycle Arrest ◽  
A Cell ◽  
Control Cell Division

ABSTRACT p107 functions to control cell division and development through interaction with members of the E2F family of transcription factors. p107 is phosphorylated in a cell cycle-regulated manner, and its phosphorylation leads to its release from E2F. Although it is known that p107 physically associates with E- and A-type cyclin/cyclin-dependent kinase 2 (Cdk2) complexes through a cyclin-binding RXL motif located in the spacer domain, the mechanisms underlying p107 inactivation via phosphorylation remain poorly defined. Recent genetic evidence indicates a requirement for cyclin D1/Cdk4 complexes in p107 inactivation. In this work, we provide direct biochemical evidence for the involvement of cyclin D1/Cdk4 in the inactivation of p107's growth-suppressive function. While coexpression of cyclin D1/Cdk4 can reverse the cell cycle arrest properties of p107 in Saos-2 cells, we find that p107 in which the Lys-Arg-Arg-Leu sequence of the RXL motif is replaced by four alanine residues is largely refractory to inactivation by cyclin D/Cdk4, indicating a role for this motif in p107 inactivation without a requirement for its tight interaction with cyclin D1/Cdk4. We identified four phosphorylation sites in p107 (Thr-369, Ser-640, Ser-964, and Ser-975) that are efficiently phosphorylated by Cdk4 but not by Cdk2 in vitro and are also phosphorylated in tissue culture cells. Growth suppression by p107 containing nonphosphorylatable residues in these four sites is not reversed by coexpression of cyclin D1/Cdk4. In model p107 spacer region peptides, phosphorylation of S640 by cyclin D1/Cdk4 is strictly dependent upon an intact RXL motif, but phosphorylation of this site in the absence of an RXL motif can be partially restored by replacement of S643 by arginine. This suggests that one role for the RXL motif is to facilitate phosphorylation of nonconsensus Cdk substrates. Taken together, these data indicate that p107 is inactivated by cyclin D1/Cdk4 via direct phosphorylation and that the RXL motif of p107 plays a role in its inactivation by Cdk4 in the absence of stable binding.

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