1

vFLIP-IKK BlockerHelix Mimetic

Edith Chan

WIBR

2

Cleft1 Interactions• Residues involved in this region are

• F238 – all hydrophobic interaction, enclosed by F53, F79, L80, P54, and A57.

• D242 and K246 – enclosed by H83,T87,Y90,S89

• K246 has a H-bond with C=O of M88

• D242 has a H-bond to H83

• Mutation study showed that A57L has impaired the forming of the complex. P54G shows a reduction in affinity while Y90L retains affinity.

• D242R mutant has rendered IKK largely incapable of forming a complex.

Ala57L

Pro54G

Tyr90F

FQEYDNHIK

3

Aryl sulfonamides• Aryl sulfonamides have been used in both p53-HDM2 and Bcl-2 as inhibitors

• Cyclacel (Dundee) has developed good p53-HDM2 compounds that potently and selectively killed cancer cells through induction of apoptosis. There is no publication except a patent. The IC50 ranges from 20-100 M. How these compounds interact with the protein is not elucidated.

S

S

OO

N

R

R

R

SOO

NS

N+

O

O

Cl

F

FF

SOO

NS

F

FF

F

FF

Cl

N+

O

O

SOO

NS

H

N+

O

O

Cl

S

S

OO

N

R

R

R

4

First series - Conformations

SOO

NS

H

N+

O

O

Cl

• This compound has mainly two rotatable bonds.

• Conformational analysis showed that there are mainly 2 classes of conformations.

• The lower energy ones – 2 rings come closer together – a bent conformation

• The higher energy ones adapt more linear geometry

S

S

OO

N

R

R

R

5

2nd series - Conformations• This compound has a couple of

rotatable bonds, however, it is more rigid than one thought.

• After performing conformation analysis, there are mainly two classes of conformations – in either cases, two of the aromatics rings will face each other as hydrophobic collapse.

• The lowest energy one has phenyl and thiopene rings facing each other.

• The higher energy one is two phenyl rings facing each other. The two CF3 groups repel each other.

• Again, both are bent comformation.

SOO

NS

F

FF

F

FF

Cl

N+

O

O

S

S

OO

N

R

R

R

6

X-ray confirmation

• There are quite a nuber of structures that have sulfonamides in the X ray database.

• Shown here are two different structures – similar to series 1 and 2 mentioned above.

• Both X-ray show a bent conformation.

SO O

N

S

N+

O

O

O

O

S

O O

N

O

N

ON

O

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Overlays with helix peptide

• The bent conformation of the sulfonamides is a good mimic for 2 of the residues on the IKK- helix -FxxxDxxxK

8

Compound Acquisition

• Limited selection with thiopene substitution – search with phenyl.

• R1 and R2 – a combintion of – acidic

– polar

S

N+

N

O

O

O

O

S

S

OO

N

R

R

R

S

OO

N

R2

R3R1

S

N

O O

NH O

SN+

N

O

OO

O

S

N

O O

O

OH

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Search strategy

• Search with substructure (- all those not wanted

• - MW <550 and rb < 6

S N

O

O

NS

O

O

NN

10

• p53-HDM2 inhibitor

• IC50 = 100-300 nM• Best compound – 4-(S),5-(R)-

imidazoline• Racemic mixture will also work• Oral administration of 200 mg/kg

twice daily for 3 weeks on mice was well-tolerated

• This treatment of mice established with tumours resulted in 80% inhibition of tumour growth.

N

N

R

R

NO N R2

O

R3

Nutlins

• Nutlins are named geographically after Hoffmann-La Roche’s research site in Nutley, N.J.

• This series of compounds are the only p53 mimetic that have in vivo activity

• Although these are custom synthesized compounds, a few of them can be obtained from the NCI for free.

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N

NBr

Br

N

O

N

O

O

O

1rv1

Nutlins – X-ray structure

Phe(Phe)(Asp)Trp

(Lys)Leu

Phe Trp

Leu

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NCI compounds

N

N

N

N

ON

N

NS

N N

N S

H

N

NS

N N

N S

H

9054 627018

650819 650820

N

NMeO

MeO

OMe

Aurora feinchemie 586999

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IC50 ~ 20uM (p53-HDM2)

Isoindolinones

N

O

O

Cl

O

O

N

O

NO

RN

O

O

R2

N

O

O Phe(Phe)

Trp(Asp)

Leu(Lys)

PhePheAsp

14

Some examples

N

NH

O

O

N

CH3

N

NH

O

O

O

O

CH3

N

NH

O

OO

O

OCH3

CH3

N

O

OHO

O

O

CH3

CH3