How do the Anti-HIV drugs woks?

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

• Content
• The step of HIV life cycle that might be stopped.
• The types of anti-HIV drugs that we have now

• Reverse Transcriptase Inhibitors
• Integrase Inhibitors
• Protease Inhibitors

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The step of HIV life cycle that might be stopped.
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1.Attachment 2.Reverse transcriptase 3.Integrase
transcription 4.Translation 5.viral
protease 6.assembly budding
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The step of HIV life cycle that might be stopped.
1.Attachment
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The step of HIV life cycle that might be stopped.
2.Reverse Transcriptase
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The step of HIV life cycle that might be stopped.
3.Integration,Transcription
Viral DNA joins host DNA
Making multiple viral RNAs
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The step of HIV life cycle that might be stopped.
4.Translation
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The step of HIV life cycle that might be stopped.
5.Viral Protease
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The step of HIV life cycle that might be stopped.
6.Assembly Budding
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The step of HIV life cycle that might be stopped.
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Types of anti-HIV drugs that we have now.

• Reverse Transcriptase Inhibitors
• Integrase Inhibitors (clinical trial)
• Protease Inhibitors

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Reverse Transcriptase Inhibitor

• Nucleoside analog
• E.g. AZT,ddI,ddC,d4T
• Non-nucleoside analog
• E.g. Nevirapine,Delavirdine

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Reverse Transcriptase Inhibitor
Nucleoside analog

• These agents are both inhibitors and substrates
  of RT, broad in family of 2-3-dideoxynucleoside
• Need metabolism before functional
• Competitive inhibition with dNTP
• Incorperation into the viral DNA lead to DNA
  termination

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Reverse Transcriptase Inhibitor
Nucleoside analog need metabolize
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Reverse Transcriptase Inhibitor
Nucleoside analog
Incorporation lead to DNA chain termination
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Reverse Transcriptase Inhibitor
Nucleoside analog Zidovudine or AZT
Thymidine analog 3-azido-2,3-dideoxythy
midine MW 267.24 fomular
C10H13N5O4
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Reverse Transcriptase Inhibitor
Nucleoside analog Zidovudine or AZT
The mechanism of action of AZT
Metabolize of AZT
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Reverse Transcriptase Inhibitor
Nucleoside analog Zidovudine or AZT
AZT-DP bind with NDP-K
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Reverse Transcriptase Inhibitor
Nucleoside analog Zidovudine or AZT
AZT-TP competitive inhibit RT with respect to
TTP incorporate into growing chain of DNA
AZT reduce the amount of dNTP (decreasing
competition for AZT-TP)
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Reverse Transcriptase Inhibitor
Nucleoside analog Zidovudine or AZT
AZT-TP Low concentration onhibit DNA
polymerase distrub growing of cellular DNA
chain
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Reverse Transcriptase Inhibitor
Non-nucleoside analog

• Structurally heterogenous
• Active for HIV-1 only
• Not need metabolism before functional
• Interact with a nonsubstrate binding site
• Noncompetitive inhibition

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Reverse Transcriptase Inhibitor
Non-nucleoside analog Nevirapine

• Viramune (trade name)
• MW 266.3
• fumular C15H14N4O

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Reverse Transcriptase Inhibitor
Non-nucleoside analog Nevirapine

• The machanism action of nevirapine
• bind directly to RT
• block RT activity (RNA dependent and
  DNA-dependent DNA polymerase) by distrub the RTs
  catalytic site (110 Asp,185Asp and 186 Asp triad)

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Reverse Transcriptase Inhibitor
Non-nucleoside analog Nevirapine

• not compete with template or nucleoside
  tritposphate
• not inhibit HIV-2 RT and cellular DNA polymerase

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Integrase Inhibitor

• HIV integrase is a viable therapeutic strategy
  that will abort completion of the viral life
  cycle
• The commercial drug of this type not have yet
  now.
• Some drug just under clinical trial.
  E.g. Zintevir currently in Phase I/II clinical
  trial.

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Integrase Inhibitor

• Overview of integration
• the formation of the ISC
• the 3-processing in reaction
• the DNA strand transfer

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Integrase Inhibitor
HIV-Integrase

• 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)

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Integrase Inhibitor

• Different approches to interfering the
  integration
• triple helix-mediated inhibition
• inhibition IN by peptides derived from
  combinatirial peptides chemistry.
• Screening of chemical libraries and natural
  compounds.
• Inhibition by G-quartet forming oligonucleotides

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Integrase Inhibitor

• Triple helix-mediated inhibition
• oligonucleotide readly form stable complex with
  viral DNA
• triplex formation prevent catalytic function of IN

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Integrase Inhibitor

• Inhibition IN by peptides derived from
  combinatirial peptides chemistry
• .find critical potion of IN by change amino acid
  that make IN loss its functional

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Integrase Inhibitor

• Screening of chemical libraries and natural
  compounds.
• .find the chemical ( oligonucleotide-base) that
  inhibit function of IN .
• Device into 3 categories
• DNA binding agent
• Polyhydroxylated aromatic compound
• Nucleotides

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Integrase Inhibitor

• Inhibition by G-quartet forming oligonucleotides
• oligonucleotides composed of base deoxyguanosine
  and thymidine
• in presence of K, Its form G-quartet
• G-quartet can inhibit HIV replication by
• inhibit viral entry into cell
• and/or inhibition HIV IN

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Integrase Inhibitor
Zintevir or AR-177

• stable oligonucleotides of 17 nucleotides
• composed only deoxyguanosine and thymidine,with
  single phosphorothioate internucleoside linkages
  at 5 and 3 end.
• Fumular
• 5-GTGGTGGGTGGGTGGGT-3

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Integrase Inhibitor
Zintevir or AR-177

• Form a highly stable intramolecular four-stranded
  DNA contain two stacked G-quartet
• Zintevir (G-quartet) inhibit HIV-1 IN activity

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Integrase Inhibitor
Zintevir or AR-177

• The machanism of action of Zintevir
• its inhibit integration in only step of the
  formation of ISC by
• G-quartet interact with IN
• it not bind to DNA binding domain but its
  interact with zinc finger domain of IN
• IN cant form active form (oligomer)
• IN cant bind with viral DNA

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Protease Inhibitor
Protease enzyme

• As aspartyl protease.
• Consist of 2 symmetric subunit
• each subunit consist 99 amino acid
• single active site
• catalytic site conserve catalytic triads (
  Asp-Thr-Gly)

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Protease Inhibitor
Protease enzyme

• Cleavage polypeptide to functional enzyme and
  structural protein
• muation in catalytic site (Asp-gtAla) cause
  immature virus (cant infect new cell)
• HIV protease no cross-reactivity with human
  cellular protease

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Protease Inhibitor
Activities of HIV protease enzyme
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Protease Inhibitor
Protease inhibitor

• Slow down the action of HIV protease
• e.g. Ritonavir, Indinavir,Saquinavir

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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 protease inhibitor
  complex cause enzyme not functional properly.

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Protease Inhibitor
Native HIV Protease
HIV Protease with inhibitor
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Protease Inhibitor
Protease inhibitor Ritonavir

• Norvir (trade name) or ABT-583
• a white-to light-tan powder
• formular C37H48N6O5S2
• MW 720.95

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Protease Inhibitor
Protease inhibitor Ritonavir

• A peptidomimetic inhibitor for HIV-1,2 protease
• Its directly interact with HIV protease that
  cause this enzyme not function
• the interaction is hydrophobic interaction

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Protease Inhibitor
Protease inhibitor Ritonavir

• hydrophobic interaction of P3 isopropylthiazolyl
  group of ritonavir with active side chain of
  valine-82 (V82) of HIV protease
• mutation in V82 to Ala,Phe or Thr cause ritonavir
  resistance

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Protease Inhibitor
Protease inhibitor Ritonavir

• Its metabolized by CYP 3A4
• and also a potent inhibitor of CYP 3A4
• inhibition of CYP by the unhindered nitrogen atom
  on the unsubatituted P2 5-thiazolyl group with
  bind directly to the heme in the CYP active site

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Protease Inhibitor
Protease inhibitor Ritonavir
P3 isopropylthiazoly group
P2 5-thiazoly group
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Protease Inhibitor

• Protease - Ritonavir inhibitor complex.

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Thank you for your attention