How do the Anti-HIV drugs woks? By Tawitch Suriyo Master degree of Toxicology Mahidol University.

How do the Anti-HIV drugs How do the Anti-HIV drugs woks?woks?

ByBy

Tawitch Suriyo Tawitch Suriyo

Master degree of Toxicology Master degree of Toxicology

Mahidol University Mahidol University

- How do anti HIV drugs work?

ContentContent

• The step of HIV life cycle that might be stopped.

• - The types of anti HIV drugs that we have now • Reverse Transcriptase Inhibito

rs

• Integrase Inhibitors

• Protease Inhibitors

The step of HIV life cycle that might be stopped.

11

2233

5566

441.Attachment

2.Reverse transcccccccc

3. &Integrase transcr i pt i on

4.Translation

5.viral protease

6. &assembly bcccccc

1.Attachment1.Attachment



2.Reverse Transcriptas 2.Reverse Transcriptasee


3.Integration,Transcript3.Integration,Transcriptionion

Viral DNA joins host DNA

Making multiple viral RNAs


4.Translation4.Translation


5.Viral Protease5.Viral Protease


6.Assembly & Budding6.Assembly & Budding


Types of anti-HIV drugs that we have now.

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• Integrase Inhibitors (clinical trial)

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Reverse Transcriptase Inhibitor

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• - Non nucleoside analog E.g. Nevirapine,Delavirdine


Nucleoside analog • These agents are both inhibitors a

nd substrates of RT, broad in famil - -y of 2’ 3’ dideoxynucleoside

• Need metabolism before functional

• Competitive inhibition with dNTP

• Incorperation into the viral DNA le ad to DNA termination


Nucleoside analog need metabolize


Nucleoside analog +Incorporation lead to DNA chain termination


Nucleoside analog : Zidovudine oreee + Thymidine analog - - -+ 3’ azido 2’,3’ dideoxythymidine + MW 267.24 + fomular C

10H13

N5

O4


Nucleoside analog : Zidovudine oreee The mechanism of action of AZT +Metabolize of AZT


Nucleoside analog : Zidovudine oreee AZT-DP bind with NDP-K


Nucleoside analog : Zidovudine oreee -AZT TP

+competitive inhibit RT with respe ct t o TTP

+incorporate into growing chain ofDNA +AZT reduce the amount of dNTP (

-decreasing competition for AZT TP)


Nucleoside analog : Zidovudine oreee -AZT TP

+Low concentration onhibit DNA polymerase

+distrub growing of cellular DNA c hai n


Non-nucleoside analog• Structurally heterogenous

• - Active for HIV 1 only

• Not need metabolism before functional

• Interact with a nonsubstrate bindingsite

• Noncompetitive inhibition


- Non nucleoside analog : Nevirapine

• Viramune (trade name)

• MW 2 6 6 .3

• fumular C15

H14

N4

O



The machanism action of nevirapine

+bind directly to RT

+block RT activity (RNA depend - ent and DNA dependent DNA poly

merase) by distrub the RT’s catalyti c si t e (110 Asp,185Asp and 186 Asp tri

ad)



+not compete with template or nuc leoside tritposphate

- +not inhibit HIV 2 RT and cellular D NA polymerase

Integrase Inhibitor

• HIV integrase is a viable therapeutic strateg y that will abort completion of the viral life cy

cle

• The commercial drug of this type not h ave yet now.

• Some drug just under clinical trial.

E.g. Zintevir currently in Phase I/II clinical trial.

Integrase Inhibitor

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• the formation of the ISC

• - the 3 ’ processing in reaction

• the DNA strand transfer

Integrase Inhibitor

e ee -eeeeeeeee• a protein of 32 kDa

• function for intergrate viral cDNA into human DNA

• recognizes specific sequence in LTR in viral cDNA

• composed of 3 functional domain

• active form is oligomer ( by oligomerization)

Integrase Inhibitor

e eeeeeeee eeeeeeeee ee eeeeeeeeeee eee eeeeeeeeeee• - triple helix mediated inhibition• inhibition IN by peptides derived from

combinatirial peptides chemistry.• Screening of chemical libraries and na

tural compounds.• - Inhibition by G quartet forming oligonucleotides

Integrase Inhibitor

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• oligonucleotide readly form stable co mplex with viral DNA

• triplex formation prevent catalytic fun ction of IN

Integrase Inhibitor

Inhibition IN by peptides derived from c ombinatirial peptides chemistry

• .find critical potion of IN by change am ino acid that make IN loss its functional

Integrase Inhibitor

eeeeeeeee ee eeee eeee eeeeeeeee eee natural compounds.

• -.find the chemical ( oligonucleotide ba se) that inhibit function of IN .

• Device into 3 categories• +DNA binding agent• +Polyhydroxylated aromatic compound• +Nucleotides

Integrase Inhibitor

- Inhibition by G quartet forming oligonueeeeeeeee

• oligonucleotides composed of base de oxyguanosine and thymidine

• -in presence of K+, Its form G quartet• - G quartet can inhibit HIV replication bc• +inhibit viral entry into cell• +and/or inhibition HIV IN

Integrase Inhibitor

• stable oligonucleotides of 17 nucleotides• composed only deoxyguanosine and t

hymidine,with single phosphorothioate internucleoside linkages at 5 ’ and 3 ’

end.•Fumular• - -5 3’ GTGGTGGGTGGGTGGGT ’

-177ZintevirorAR

Integrase Inhibitor

• Form a highly stable intra - molecular four stranded D

-NA contain two stacked Gquartet

• - Zintevir (G quartet) inhibi - t HIV 1 IN activity

-177ZintevirorAR

Integrase Inhibitor

The machanism of action of Zintevir• its inhibit integration in only step of th

e formation of ISC by• - +G quartet interact with IN• +it not bind to DNA binding domain

but its interact with zinc finger domain of I N

• +IN can’t form active form (oligomer)• +IN can’t bind with viral DNA

-177ZintevirorAR

Protease Inhibitor

Protease enzyme

• As aspartyl protease.

• Consist of 2 symmetric subunit

• each subunit consist 9 9 aminoacid

• single active site

• catalytic site conserve catalytic tr - -iads ( Asp Thr Gly)

Protease Inhibitor

Protease enzyme

• Cleavage polypeptide to functional e nzyme and structural protein

• - muation in catalytic site (Asp >Ala) cause immature virus (can’t infect ne

w cell)

• - HIV protease no cross reactivity with human cellular protease

Protease Inhibitor

Activities of HIV protease enzyme

Protease Inhibitor

Protease inhibitor

• Slow down the action of HIV protease

• e.g. Ritonavir, Indinavir,Saquinavir

Protease Inhibitor

Protease inhibitor

• Base on transitionstate mimetics of peptide substrate

• interact with catalytic residues and displace a structural water molecule

• the interaction protease and proteas e inhibitor complex cause enzyme not

functional properly.

Protease Inhibitor

Native HIV Protease

HIV Protease with inhibitor

Protease Inhibitor

Protease inhibitor : Ritonavir

• -Norvir (trade name) or ABT 583

• - - a white to light tan powder

• formular C37

H48

N6

O5

S2

• 72095MW .

Protease Inhibitor


• -A peptidomimetic inhibitor for HIV 1,2 protease

• Its directly interact with HIV protea se that cause this enzyme not functi

on

• the interaction is hydrophobic interaction

Protease Inhibitor


• hydrophobic interaction of P’3 isopr opylthiazolyl group of ritonavir with

- active side chain of valine 82 (V82) o f HIV protease

• mutation in V8 2 to Ala,Phe or Thr cause ritonavir resistance

Protease Inhibitor


• Its metabolized by CYP 3 A4

• and also a potent inhibitor of CYP 3A4

• inhibition of CYP by the unhindered nitrogen atom on the unsubatituted P

- 2 ’ 5 thiazolyl group with bind direct ly to the heme in the CYP active site

Protease Inhibitor


P3’ isopropylt hiazoly group

-P2’ 5 thia zoly group

Protease Inhibitor

• - Protease Ritonavir inhibitor complex.

Thank you for your attention

How do the Anti-HIV drugs woks? By Tawitch Suriyo Master degree of Toxicology Mahidol University.

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