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Prevents damaged cells fromproliferating

Promotes senescence

Triggers programmed cell death

Three amino acids, Phe19, trp23and Leu26 fit tightly in theMDM2 binding pocket

P53 Tumoursuppressor

E3 ubiquitin ligase to degrade p53Inactivates trancription by binding to

and blocking the TAD in P53Has a deep p53 binding pocket

MDM2

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Mdm2 acts as an antagonist of p53 p53 transcriptionally activates MDM2 which causes its degradation Creates a negative feedback loop Degrades p53 by adding a ubiquitin to the lysine on the C-terminus

Disruption of the p53-MDM2 interaction by different can lead to theactivation of p53 and tumor growth inhibition

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Cis-imidazoline analogs

Nutlin-1, Nutlin-2 and Nutlin-3

Discovered by screening a chemical library byVassilev et al. 2004 Roche pharmaceuticals,

Nutley N.J

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Binds to p53 binding pocket of mdm2

Inhibit the interaction between mdm2 and p53

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Screening

Screened a diverse library of syntheticchemicals

Several lead structures were identified andoptimized for potency and selectivity

Investigationon binding

Tested all 3 Nutlins enantiomers for percentagebinding of mdm2-p53

Nutlin 3a was the most potent

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Mode ofbinding

Determined the crystal structure of thehuman MDM2Nutlin-2 complex

Binds to the p53 binding site onMDM2

The inhibitor mimics the interactions

of the p53 Replaces the helical structure of the

p53 peptide

Ethoxy Phe19, BromophephenylTrp23, Other Leu26

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1. Nutlins are able to dislodge p53 from binding with MDM2

2. Works in a transcription dependent way

Ideal Resultof Inhibition

Stabilization of the p53 protein

Activation of MDM2 expressionActivation of the p53 pathway

Cell cycle arrest at G1 and G2 or apoptosis

Cell cyclesarrest and

apoptosis

Used human cancer cells, RKO Examine levels of p53 and mdm2

Dose dependent increase

Showed accumulation of p53 and mdm2 consistent withactivation of p53 pathway

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Effect on growth andviablity of cancer cells

Used a MTT assay

Determined that Nutlins workonly for cancer which hadwild type p53

1C 50 value was lesser thatmutants

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Activation of the transcription-independentpathway initiates p53-mediated apoptosis inCLL

Nutlin-3a and fludarabine increased p53levels

Induced apoptosis in wild-type p53 cells butnot in cells with mutant p53

Fludarabine uses both mechanisms to induceapoptosis

Specific mechanisms remain unknown

2006,Transcriptionindependent

anddependent

pathways inCLL cells

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Nutlin causes monoubiquitinatedcytoplasmic p53 accumulation and

translocation to mitochondria MDM2 still retains its E3 ligase activity

Nutlin-induced mitochondrial p53translocation is rapid

Without transcription arm in p53 geneeffect of Nutlins greatly increased

2009,

Mitochondrialp53 Nutlin-induced

apoptosis in

acute(RKO)

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Effects of Velcade increased by Nutlin-3

Investigate the role of mitochondrial function inp53 induced apoptosis

P53 co-localised with a mitochondrial marker

P53 protein elevated in cells with Nutlins

Not sufficient to promote apoptotic response toNutlin

Nutlin could utilize both of p53's pathways topromote apoptosis

2010,Nutlins

and other

chemicals

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8 years have passed since the initial discoveryof Nutlins

Drug design is a very time consuming process

Potential non-genotoxic drug to treat blood andcolon

Still, further studies are still needed to ensureits true therapeutic potential

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Andreeff, M., et al., 2006. Mdm2 inhibitor Nutlin-3a induces p53-mediated apoptosis by transcription dependent and transcription-independent mechanisms and may overcome Atm-mediatedresistance to fludarabine in chronic lymphocytic leukemia. Blood,108, p993-1000.

Chang, H., et al., 2010. MDM2 antagonist nutlin plus proteasomeinhibitor velcade combination displays a synergistic anti-myelomaactivity. Cancer Biology and Therapy, 47, p936-44.

Iwakuma, I. and Lozano, G., 2003. MDM2, An Inroduction.Moelcular Cancer Reserch, 1(14), p993-1000.

Moll, U.M., et al., 2010. The transcription- Independentmitochondrial p53 program is a major contributor to nutlin-induced apoptosis in tumor cells. Cell Cycle, 8, p1711-9.

Moll, U.M. and Petrenko, O., 2003. The MDM2-p53 interaction.

Molecular Cancer Research, 1(14), p1001-1008. Vassilev, L.T., et al., 2004. In vivo activation of the p53 pathway bysmall-molecule antagonists of MDM2. Science, 303, p844-8.

Zhang, C. and Lu, H., 2010. Nutlinstwo roads towards apoptosis.Cancer Biology and Therapy, 10(6), p579-581.