Roscovitine‐activated HIP2 kinase induces phosphorylation of wt p53 at Ser‐46 in human MCF‐7 breast cancer cells

Węsierska‐Gądek, Józefa; Schmitz, M. Lienhard; Ranftler, Carmen

doi:10.1002/jcb.21211

Cited by 47 publications

(48 citation statements)

References 24 publications

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“…Roscovitine, a promising drug with anticancer action (10,22,23), has recently been shown to affect voltage-dependent calcium channels (14 -16, 19) and potassium channels (15,24). From our previous findings (19), we generated the hypothesis that (R)-roscovitine-induced slowed activation and enhanced inactivation were mediated by a common binding site.…”

Section: Discussionmentioning

confidence: 99%

Roscovitine Binds to Novel L-channel (CaV1.2) Sites That Separately Affect Activation and Inactivation

Yarotskyy

Gao

et al. 2010

Journal of Biological Chemistry

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L-type (Ca V 1.2) calcium channel antagonists play an important role in the treatment of cardiovascular disease. (R)-Roscovitine, a trisubstituted purine, has been shown to inhibit L-currents by slowing activation and enhancing inactivation. This study utilized molecular and pharmacological approaches to determine whether these effects result from (R)-roscovitine binding to a single site. Using the S enantiomer, we find that (S)-roscovitine enhances inactivation without affecting activation, which suggests multiple sites. This was further supported in studies using chimeric channels comprised of N-and L-channel domains. Those chimeras containing L-channel domains I and IV showed (R)-roscovitine-induced slowed activation like that of wild type L-channels, whereas chimeric channels containing L-channel domain I responded to (R)-roscovitine with enhanced inactivation. We conclude that (R)-roscovitine binds to distinct sites on L-type channels to slow activation and enhance inactivation. These sites appear to be unique from other calcium channel antagonist sites that reside within domains III and IV and are thus novel sites that could be exploited for future drug development. Trisubstituted purines could become a new class of drugs for the treatment of diseases related to hyperfunction of L-type channels, such as Torsades de Pointes.Cardiac L-type (Ca V 1.2) channels are central to the regulation of a number of physiological processes (1, 2). Activation of these channels in cardiac and smooth muscle generates the calcium influx that triggers calcium release from the sarcoplasmic reticulum (3) to induce contraction. In contrast, inactivation of these channels provides a negative feedback mechanism to limit calcium influx into the cardiac myocyte, which helps protect from excessive calcium influx that can lead to cardiac arrhythmias (3). L-channel antagonists are routinely used to treat cardiovascular diseases, such as hypertension and angina pectoris (4 -8). Therefore, drugs that inhibit L-channel function have high clinical relevance.Roscovitine is a 2,6,9-trisubstituted purine that was originally developed as a selective blocker of cyclin-dependent kinases (9) and is currently undergoing phase II clinical trials as an anticancer drug (10). It has recently become apparent that roscovitine can affect voltage-dependent ion channels at clinically relevant concentrations (10 -50 M) (10 -13). We (14, 15) and others (16,17) have shown that (R)-roscovitine differentially affects voltage-dependent calcium channels. (R)-Roscovitine has two effects on Ca V 2 channels (N-type, P/Q-type, and R-type), which are a rapid onset agonist effect and a more slowly developing antagonist effect (14, 15). The agonist effect results from (R)-roscovitine specifically binding to activated Ca V 2 channels to slow channel closing (14, 15), which results in a significant enhancement of action potential induced calcium influx (14). The antagonist effect appears to result from (R)-roscovitine preferentially enhancing occupancy of a "resting" inac...

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Section: Discussionmentioning

confidence: 99%

Roscovitine Binds to Novel L-channel (CaV1.2) Sites That Separately Affect Activation and Inactivation

Yarotskyy

Gao

et al. 2010

Journal of Biological Chemistry

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“…First, we used the cell line MCF7, in which the level of HIPK2 is modest (Hofmann et al, 2002), and stimulated its activity by using Roscovitine, a known HIPK2 activator (Wesierska-Gadek et al, 2007). The induction of p21, which is triggered by HIPK2 under these conditions (Wesierska-Gadek et al, 2007), served as a positive control of Roscovitine effect ( Figure 4b). The Roscovitine treatment caused a decrease of ZBTB4 abundance ( Figure 4b).…”

Section: Identification Of Hipk2 As a Zbtb4 Interactormentioning

confidence: 99%

The human protein kinase HIPK2 phosphorylates and downregulates the methyl-binding transcription factor ZBTB4

et al. 2009

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HIPK2 is a eukaryotic Serine-Threonine kinase that controls cellular proliferation and survival in response to exogenous signals. Here, we show that the human transcription factor ZBTB4 is a new target of HIPK2. The two proteins interact in vitro, colocalize and associate in vivo, and HIPK2 phosphorylates several conserved residues of ZBTB4. Overexpressing HIPK2 causes the degradation of ZBTB4, whereas overexpressing a kinasedeficient mutant of HIPK2 has no effect. The chemical activation of HIPK2 also decreases the amount of ZBTB4 in cells. Conversely, the inhibition of HIPK2 by drugs or by RNA interference causes a large increase in ZBTB4 levels. This negative regulation of ZBTB4 by HIPK2 occurs under normal conditions of cell growth. In addition, the degradation is increased by DNA damage. These findings have two consequences. First, we have recently shown that ZBTB4 inhibits the transcription of p21. Therefore, the activation of p21 by HIPK2 is twopronged: stimulation of the activator p53, and simultaneous repression of the inhibitor ZBTB4. Second, ZBTB4 is also known to bind methylated DNA and repress methylated sequences. Consequently, our findings raise the possibility that HIPK2 might influence the epigenetic regulation of gene expression at loci that remain to be identified.

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“…HIPK2 can be activated by several types of stress, including ultraviolet, ionizing radiation and drugs, such as cisplatin (CDDP), adriamycin (ADR) and roscovitin (D 'Orazi et al, 2002;Hofmann et al, 2002;Di Stefano et al, 2004a;Dauth et al, 2007;Wesierska-Gadek et al, 2007). On the other hand, few studies report that HIPK2 is inactivated in tumors by some mechanisms including hypoxia-driven proteasomal degradation that consequently also affect p53's function leading to chemoresistance and tumor progression (see below).…”

Section: Introductionmentioning

confidence: 99%

Regulation of p53 activity by HIPK2: molecular mechanisms and therapeutical implications in human cancer cells

et al. 2010

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The p53 protein is the most studied tumor suppressor and the p53 pathway has been shown to mediate cellular stress responses that are disrupted when cancer develops. After DNA damage, p53 is activated as transcription factor to directly induce the expression of target genes involved in cell-cycle arrest, DNA repair, senescence and, importantly, apoptosis. Post-translational modifications of p53 are essential for the activation of p53 and for selection of target genes. The tumor suppressor homeodomain-interacting protein kinase-2 (HIPK2) is a crucial regulator of p53 apoptotic function by phosphorylating its N-terminal serine 46 (Ser46) and facilitating Lys382 acetylation at the C-terminus. HIPK2 is activated by numerous genotoxic agents and can be deregulated in tumors by several conditions including hypoxia. Recent findings suggest that HIPK2 active/inactive protein can affect p53 function in multiple and unexpected ways. This makes p53 as well as HIPK2 interesting targets for cancer therapy. Hence, understanding the role of HIPK2 as p53 activator may provide important insights in the process of tumor progression, and may also serve as the crucial point in the diagnostic and therapeutical aspects of cancer.

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Roscovitine‐activated HIP2 kinase induces phosphorylation of wt p53 at Ser‐46 in human MCF‐7 breast cancer cells

Cited by 47 publications

References 24 publications

Roscovitine Binds to Novel L-channel (CaV1.2) Sites That Separately Affect Activation and Inactivation

Roscovitine Binds to Novel L-channel (CaV1.2) Sites That Separately Affect Activation and Inactivation

The human protein kinase HIPK2 phosphorylates and downregulates the methyl-binding transcription factor ZBTB4

Regulation of p53 activity by HIPK2: molecular mechanisms and therapeutical implications in human cancer cells

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