Development of Potent & Selective Inhibitors

of ecto -5 -́Nucleotidase Based on an

Anthraquinone Scaffold

KORA UPENDRA REDDY

2010H146037H

5 May 2011 1

Function of ecto Nucleotidases

Extracellular

Nucleotide Triphosphates

-Diphosphates

-Monophosphates

[ATP,AMP,UDP,UMP,GMP]

Nucleosides

Source of Extracellular

nucleotides

Nerve terminals

Hypoxic tissue

Salvage pathways

Cell membrane

transport

Damaged/dying cells

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Families of ectonucleotidases

1) Ectonucleoside triphosphate diphosphohydrolases

(E-NTPDase).

2) Ectonucleotide pyrophosphate/phosphodiesterases

(E-NPPS).

3) Alkaline phosphatases.

4) Ecto-5ʹ -nucleotidase.

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Receptors

• Extracellular nucleosides & nucleotides exert their action by

P1(adenosine receptor)

Subtypes

A1

A2a

A2b

A3

P2(Nucleotide receptor)

P2X[Ligand gated]

Short term processes

exocrine/endocrine

secretions

immune response

platelet aggregation

P2Y[G-protein coupled]

Long term processes

cell proliferation

differentiation

migration

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NTPDase E-NPPS AP eN

Location Nervous tissue,

Golgi complex,

liver,

kidney

Expressed in

capillaries of

brain

Bone tissue All tissues

Mechani

sm

ATP,ADP to

AMP

ATP,ADP to

AMP

AMP to

Adenosine

AMP,

UMP,IMP

& GMP

to

Adenosine

Function Mediate the

termination of

ATP signaling in

the synaptic

cleft

Ectoenzymatic

catabolism of

extracellular

nucleotides

Development

&

mineralization

Of bones

Activates

the P1

receptors

by

producing

adenosine

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Ectonucleotidase role in Tumor growth

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LPC=lyso phosphotidyl choline

LPA=lyso phosphotidic acid

eN Inhibitors

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Synthesis

Efficient microwave assisted Ullmann Reaction:

Reaction conditions:

pH=6-7

copper powder

microwave irradiation at 100-120 ͦ C

time =5 to 24 min

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SAR

Lead moleculePosition Increased activity Decreased activity

C-2 -SO3H -CH3

C-4

Phenyl

ring

substituti

ons

Unsubstituted

phenyl amino ring

-OH at o-/p-

position of phenyl

Halogen at

p-position

Amino group at

p-position

Carboxylate at

o-position

Benzyl amino,

Phenethylamino

Replacement of

aromatic with

aliphatic residues

Methylated –OH.

Carboxylate at

m/p-position

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Molecular modeling

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Enzyme inhibition assays

Instrument : Capillary electrophoresis-UV method

High substrate concentrations were used because of low

sensitivity

Quantifying product: Adenosine

Ki values calculated by using IC-50 values

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Selectivity

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Toxicity

Hydroxyl substituted Anthraquinones bearing basic side chains

leads to carcinogenicity

Intercalate into DNA

Inhibit DNA topoisomerase II complex

Form reactive oxygen species

Lacking phenolic basic side chains found to be non toxic

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Conclusion

During optimization five compounds [4,23,45,52,53]

showed more inhibitory effect with submicromolar

concentrations

Most potent compounds proved to be selective versus

other ecto nucleotidases & P2 receptors

Treatment for cancers

Anthraquinone scaffold appears to be privileged structure

of nucleotide binding protein targets

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