scholarly journals Cyclin dependent kinase 5 and its interacting proteins in cell death induced in vivo by cyclophosphamide in developing mouse embryos

2002 ◽  
Vol 9 (4) ◽  
pp. 421-430 ◽  
Author(s):  
Y Zhu ◽  
L Lin ◽  
S Kim ◽  
D Quaglino ◽  
R A Lockshin ◽  
...  
Keyword(s):  
Cell Death ◽  
Mouse Embryos ◽  
Interacting Proteins ◽  
Cyclin Dependent Kinase ◽  
Cyclin Dependent Kinase 5

scholarly journals Activation of Cyclin-Dependent Kinase 5 Is a Consequence of Cell Death

2009 ◽  
Vol 2009 ◽  
pp. 1-11 ◽  
Author(s):  
Yixia Ye ◽  
Antonella Tinari ◽  
Walter Malorni ◽  
Richard A. Lockshin ◽  
Zahra Zakeri
Keyword(s):  
Cell Death ◽  
Cell Division ◽  
Cell Differentiation ◽  
Metabolic Changes ◽  
Cyclin Dependent Kinase ◽  
Secondary Necrosis ◽  
Kinetics Of ◽  
Cyclin Dependent Kinase 5

Cyclin-dependent kinase 5 (Cdk5) is similar to other Cdks but is activated during cell differentiation and cell death rather than cell division. Since activation of Cdk5 has been reported in many situations leading to cell death, we attempted to determine if it was required for any form of cell death. We found that Cdk5 is activated during apoptotic deaths and that the activation can be detected even when the cells continue to secondary necrosis. This activation can occur in the absence of Bim, calpain, or neutral cathepsins. The kinase is typically activated by p25, derived from p35 by calpain-mediated cleavage, but inhibition of calpain does not affect cell death or the activation of Cdk5. Likewise, RNAi-forced suppression of the synthesis of Cdk5 does not affect the incidence or kinetics of cell death. We conclude that Cdk5 is activated as a consequence of metabolic changes that are common to many forms of cell death. Thus its activation suggests processes during cell death that will be interesting or important to understand, but activation of Cdk5 is not necessary for cells to die.

Investigation of a Novel Cyclin-Dependent-Kinase (CDK) Inhibitor Cdki-73 As an Effective Treatment Option for MLL-AML

Blood ◽  
2015 ◽  
Vol 126 (23) ◽  
pp. 1365-1365 ◽  
Author(s):  
Ka Leung Li ◽  
Sarah C Bray ◽  
Diana Iarossi ◽  
Julian Adams ◽  
Longjin Zhong ◽  
...  
Keyword(s):  
Cell Death ◽  
Conflicts Of Interest ◽  
Xenograft Model ◽  
Lymphocytic Leukemia ◽  
Cyclin Dependent Kinase ◽  
T Complex ◽  
Mouse Xenograft Model ◽  
Orally Bioavailable ◽  
High Level

Abstract The Acute Myeloid Leukemia (AML) subtype characterised by translocations of the Mixed-Lineage Leukemia gene, MLL (t11q23; MLL-AML), is a particularly devastating disease with a median overall survival of only 9 months with current standard therapy. Cyclin dependent kinase (CDK) 9 inhibitors (CDK9i) directly target the CDK9/cyclin T complex (pTEFb) that is essential for activity of the MLL-fusion proteins and for transcriptional elongation, and therefore leads to reduction of transcript levels for multiple key leukemic oncogenes e.g. HOXA9, MYC and MCL1. Several observations suggest that utilising CDK9i to simultaneously target these oncogenes will be an effective strategy for AML, and MLL-AML in particular: (i) Leukemic stem cell (LSC) fractions of AML cells express a high level of MCL1, (ii) Targeting MCL1 has been demonstrated to reduce leukaemia cell survival in a murine model of MLL-ENL, (iii) MCL1 is consistently elevated in AML patients at relapse, (iv) HOXA9 is critical for leukemogenesis in many AMLs, in particular MLL-AML, (v) MYC has been shown to be a critical oncogene in MLL-AML, and (vi) CDK9 function has been shown to be important for MYC-driven tumorigenesis. Our in vitro and in vivo data support the clinical potential of a novel orally bioavailable inhibitor of CDK9, CDKI-73, as an effective therapy for MLL-AML patients. CDKI-73 is a potent inhibitor of CDK9 (Ki 3.5nM)1 and has been shown to induce down-regulation of MCL1, and cell death of Chronic Lymphocytic Leukemia (CLL) B-cells2 and Ovarian Cancer (OvCa) cells3 with nanomolar potency. At doses that are highly toxic for tumour cells, CDKI-73 shows limited toxicity for normal T- and B- Lymphocytes, Bone Marrow Mononuclear cells (BMMNC) and normal colony forming cells (CFC) from the BMMNC fraction. CDKI-73 has many favorable properties also making it an excellent clinical candidate for AML when compared to other CDK9i; in particular, CDKI-73 is (i) unique in its spectrum of inhibition, including targeting CDK6 (IC50 = 0.038 µM; a critical kinase for MLL-AML4), and is (ii) orally bioavailable (F = 56%)2, facilitating sustained in vivo target inhibition. Here we present data showing that in MLL-AML cell lines, CDKI-73 induces growth suppression and apoptosis associated with rapid loss of Myc and MCL1, and activation of PARP. In primary AML patient samples treated with 200nM CDKI-73, we have observed a similar decrease in MCL1 protein levels, with increased 7AAD uptake and Annexin-V staining, consistent with apoptotic cell death. Using a subcutaneous MV4;11 nude mouse xenograft model, we have shown that oral dosing of CDKI-73 (100 mg/kg once every 3 days for 18 days) resulted in a high level of anti-tumour efficacy (p<0.0001 compared to vehicle-treated mice), with minimal toxicity. Moreover, for an established MLL-AML patient-derived xenograft (PDX) generated in NOD/SCID-IL2RG-/- (NSG) mice we also observed significant inhibition of human AML in peripheral blood (p<0.0001), BM (p<0.05) and spleen (p<0.001) with administration of CDKI-73 at 75 mg/kg every 3 days for 15 days. In both models CDKI-73 was well-tolerated at these doses, consistent with our published and preliminary data showing differential effects of CDKI-73 on tumour versus normal cell populations. Given this data, our priority now is to establish the effectiveness of CDKI-73 across a larger panel of primary MLL-AML samples, in further patient derived AML xenografts, and as a combination treatment with AML chemotherapy. REFERENCES: 1. Shao H, Shi S, et al. (2013). J Med Chem. 56(3):640-59. 2. Walsby E, Pratt G, et al. (2014). Oncotarget. 5(2):375-85. 3. Lam F, Abbas AY, et al. (2014). Oncotarget. 5(17):7691-704. 4. Placke T, Faber K, et al. (2014). Blood. 124(1):13-23. Disclosures No relevant conflicts of interest to declare.

scholarly journals TP5, a Peptide Inhibitor of Aberrant and Hyperactive CDK5/p25: A Novel Therapeutic Approach against Glioblastoma

Cancers ◽  
2020 ◽  
Vol 12 (7) ◽  
pp. 1935
Author(s):  
Emeline Tabouret ◽  
Herui Wang ◽  
Niranjana Amin ◽  
Jinkyu Jung ◽  
Romain Appay ◽  
...  
Keyword(s):  
Dna Damage ◽  
Therapeutic Option ◽  
Selective Inhibition ◽  
G1 Arrest ◽  
Cyclin Dependent Kinase ◽  
Dna Damaging Agents ◽  
Induced Apoptosis ◽  
Cyclin Dependent Kinase 5

We examined the efficacy of selective inhibition of cyclin-dependent kinase 5 (CDK5) in glioblastoma by TP5. We analyzed its impact in vitro on CDK5 expression and activity, cell survival, apoptosis and cell cycle. DNA damage was analyzed using the expression of γH2A.X and phosphorylated ATM. Its tolerance and efficacy were assessed on in vivo xenograft mouse models. We showed that TP5 decreased the activity but not the expression of CDK5 and p35. TP5 alone impaired cell viability and colony formation of glioblastoma cell lines and induced apoptosis. TP5 increased DNA damage by inhibiting the phosphorylation of ATM, leading to G1 arrest. Whereas CDK5 activity is increased by DNA-damaging agents such as temozolomide and irradiation, TP5 was synergistic with either temozolomide or irradiation due to an accumulation of DNA damage. Concomitant use of TP5 and either temozolomide or irradiation reduced the phosphorylation of ATM, increased DNA damage, and inhibited the G2/M arrest induced by temozolomide or irradiation. TP5 alone suppressed the tumor growth of orthotopic glioblastoma mouse model. The treatment was well tolerated. Finally, alone or in association with irradiation or temozolomide, TP5 prolonged mouse survival. TP5 alone or in association with temozolomide and radiotherapy is a promising therapeutic option for glioblastoma.

scholarly journals Involvement of Cyclin Dependent Kinase 5 in M4 Muscarinic Acetylcholine Receptor-Mediated Cholinergic Transmission within the Mouse Dorsal Striatum

2021 ◽  
Author(s):  
Hu Zhou ◽  
Huaxiang Shi ◽  
Xing Li ◽  
Jingxin Zhang ◽  
Xin Sui ◽  
...  
Keyword(s):  
Motor Behavior ◽  
Neurodegenerative Disorder ◽  
Muscarinic Acetylcholine Receptor ◽  
Dorsal Striatum ◽  
Receptor Subtype ◽  
Cyclin Dependent Kinase ◽  
Patch Clamp Recording ◽  
Knockout Mouse Model ◽  
Cyclin Dependent Kinase 5

Abstract Background: An imbalance between dopamine (DA) and acetylcholine (ACh) within the striatum has reemerged as key to the pathophysiology of the neurodegenerative disorder, Parkinson's disease (PD). M4 is a prominent muscarinic ACh receptor subtype in the striatum and we have previously reported that M4 controls cyclin-dependent kinase 5 (Cdk5) / dopamine- and cAMP-regulated phosphoprotein of Mr 32 kDa (DARPP-32) activity in cultured medium spiny neurons (MSNs). However, the mechanism of this control remains unclear. Methods: Genetic, electrophysiological, and immunohistochemical approaches were used in conjunction with pharmacological methods to study isolated M4-deleted MSNs (M4-KD MSNs) and a dorsomedial striatum (DMS) M4 knockout mouse model. We examined the role of Cdk5 in M4-mediated neural cholinergic transmission and related behavior.Results: Oxotremorine M, a nonselective mAchR agonist, promoted Cdk5/P35 signaling activity in DSM MSNs both in vivo and in vitro. Either pharmacological inhibition or genetic knockdown of M4 decreased the amount of Cdk5 and DARPP-32 phosphorylation at Thr75 in dopamine 1 receptor-expressing MSNs. Furthermore, whole-cell patch-clamp recording confirmed Cdk5 is necessary for M4-mediated cholinergic inhibition of excitatory synaptic transmission in MSNs in vivo and in vitro. Concomitantly, deletion of M4 activity in the DMS caused Oxotremorine M-induced Cdk5 signaling and glutamatergic synaptic input to be altered in parallel with behavioral responses. Conclusions: We characterized a novel regulatory mechanism of Cdk5/DARPP-32 involved in M4-mediated cholinergic regulation on striatonigral neurons and on motor behavior. The findings indicate that inhibition of M4 mAChR could be a novel approach to correct the pathological conditions of PD.

scholarly journals O-GlcNAc transferase regulates glioblastoma acetate metabolism via regulation of CDK5-dependent ACSS2 phosphorylation

2021 ◽  
Author(s):  
Lorela Ciraku ◽  
Zachary A Bacigalupa ◽  
Jing Ju ◽  
Rebecca A Moeller ◽  
Rusia H Lee ◽  
...  
Keyword(s):  
Ex Vivo ◽  
Acetate Metabolism ◽  
Dependent Manner ◽  
Cyclin Dependent Kinase ◽  
Acetyl Coa ◽  
Promote Tumor Growth ◽  
Glcnac Transferase ◽  
Cyclin Dependent Kinase 5

Glioblastomas (GBMs) preferentially generate acetyl-CoA from acetate as a fuel source to promote tumor growth. O-GlcNAcylation has been shown to be elevated by increasing O-GlcNAc transferase (OGT) in many cancers and reduced O-GlcNAcylation can block cancer growth. Here, we identify a novel mechanism whereby OGT regulates acetate-dependent acetyl-CoA production by regulating phosphorylation of acetyl-CoA synthetase 2 (ACSS2) by cyclin-dependent kinase 5 (CDK5). OGT is required and sufficient for GBM cell growth and regulates acetate conversion to acetyl-CoA. Elevating O-GlcNAcylation in GBM cells increases phosphorylation of ACSS2 on Ser-267 in a CDK5-dependent manner. Importantly, we show that ACSS2 Ser-267 phosphorylation regulates its stability by reducing polyubiquitination and degradation. ACSS2 Ser-267 is critical for OGT-mediated GBM growth as overexpression of ACSS2 Ser-267 phospho-mimetic rescues growth in vitro and in vivo. Importantly, we show that pharmacologically targeting OGT and CDK5 reduces GBM growth ex vivo. Thus, the OGT/CDK5/ACSS2 pathway may be a way to target altered metabolic dependencies in brain tumors.

scholarly journals Cyclin-Dependent Kinase 5 Is Associated with Apoptotic Cell Death during Development and Tissue Remodeling

1997 ◽  
Vol 183 (2) ◽  
pp. 222-233 ◽  
Author(s):  
Qi Zhang ◽  
Harleen Singh Ahuja ◽  
Zahra F. Zakeri ◽  
Debra J. Wolgemuth
Keyword(s):  
Cell Death ◽  
Apoptotic Cell ◽  
Tissue Remodeling ◽  
Apoptotic Cell Death ◽  
Cyclin Dependent Kinase ◽  
Cyclin Dependent Kinase 5

scholarly journals Protection of cisplatin cytotoxicity by an inactive cyclin-dependent kinase

2010 ◽  
Vol 299 (1) ◽  
pp. F112-F120 ◽  
Author(s):  
Rawad Hodeify ◽  
Judit Megyesi ◽  
Adel Tarcsafalvi ◽  
Robert L. Safirstein ◽  
Peter M. Price
Keyword(s):  
Cell Death ◽  
Cyclin A ◽  
Binding Pocket ◽  
Cyclin Dependent Kinase ◽  
Wild Type ◽  
Cytochrome C Release ◽  
Endonuclease G ◽  
Cdk2 Activity

Cisplatin cytotoxicity is dependent on cyclin-dependent kinase 2 (Cdk2) activity in vivo and in vitro. A Cdk2 mutant (Cdk2-F80G) was designed in which the ATP-binding pocket was altered. When expressed in mouse kidney cells, this protein was kinase inactive, did not inhibit endogenous Cdk2, but protected from cisplatin. The mutant was localized in the cytoplasm, but when coexpressed with cyclin A, it was activated, localized to the nucleus, and no longer protected from cisplatin cytotoxicity. Cells exposed to cisplatin in the presence of the activated mutant had an apoptotic phenotype, and endonuclease G was released from mitochondria similar to that mediated by endogenous Cdk2. But unlike apoptosis mediated by wild-type Cdk2, cisplatin exposure of cells expressing the activated mutant did not cause cytochrome c release or significant caspase-3 activation. We conclude that cisplatin likely activates both caspase-dependent and -independent cell death, and Cdk2 is required for both pathways. The mutant-inactive Cdk2 protected from both death pathways, but after activation by excess cyclin A, caspase-independent cell death predominated.

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