dietary supplement use in the elderly · impact of dietary supplements on gene networks that...
TRANSCRIPT
Barry M. Forman, MD, PhDAssociate Professor
Beckman Research InstituteCity of Hope National Medical Center
Duarte, California
PolypharmacyPolypharmacy & OTCs:& OTCs:Impact of Dietary Supplements on Gene Networks Impact of Dietary Supplements on Gene Networks
that Regulate Drug Clearancethat Regulate Drug Clearance
Dietary Supplement Use in the ElderlyDietary Supplement Use in the ElderlyNational Institutes of Health
Nuclear Hormone ReceptorsCoactivator Recruitment
HREHRE
RXR Rec
TATA
Rec
CoactivatorsCoactivators
Activated TranscriptionActivated Transcription
LigandLigand
Orphan Nuclear ReceptorsA New Endocrinology
LigandsN - DNA - CNovel Ligands?
SteroidThyroidRetinoid
Vitamin D
Hormonal Ligands
SteroidsThyroidRetinoidsVitamin D
Classical Receptors
MetabolitesLipidsFatty acidsSterols Bile Acids
Xenobiotics
Orphan Receptors
SXR / PXRA steroid & xenobiotic receptor
Expression: Liver & IntestineExpression: Liver & Intestine
Target Genes: Cyp3A4Target Genes: Cyp3A4
PXRE
RXRRXR PXRPXR Ligands: PhenobarbitalRifampicinClotrimazole
Ligands: PhenobarbitalRifampicinClotrimazole
Function: Protection from Xenotoxins
Enhancement of Drug MetabolismMediator of Drug-Drug Interactions
CyclosporinHIV Protease InhibitorsBirth Control “Pill”
Function: Protection from Xenotoxins
Enhancement of Drug MetabolismMediator of Drug-Drug Interactions
CyclosporinHIV Protease InhibitorsBirth Control “Pill”
TaxolChemotherapeutic agent
Efficacy: Breast & Ovarian CancersActivity: Microtubule StabilizationMetabolism: Cyp3A4 & Cyp2C8
OAc
OHO
OAcOO
O
OOH
O
N
O
OH
H
Taxol is a Specific Activator of hPXRPXR vs other receptors
Taxol10 µM
1
5
9
13
17
21
25
29
hPXR
mPX
RER
αVD
RTR
βR
ARα
LXRα
PPAR
αPP
ARγ
PPA
R δC
ARβ
Fold
Act
ivat
ion
FXR
PXR & Taxol DegradationCyp3A4 & Cyp2C8
Primary Human Hepatocytes
Taxo
l
Rifa
mpi
-
n
Cyp 3A4
Cyp 2C8
GAPDH
Hea
rt
Brai
n
Plac
enta
Lung
Live
r
Skel
etal
Mus
cle
Kidn
ey
Panc
reas
Thym
us
Pros
tate
Test
is
Ova
ry
Smal
l int
estin
e
Col
on
Leuk
ocyt
es
Sple
en
hPXR ExpressionLiver & Intestine
Adapted from Blumberg et al. , Lehmann et al., & Bertilsson et al.
PXR Function in the Intestine?Regulation of MDR1
Taxo
l
Rifa
mpi
-
n
MDR1
Human Intestinal CellsLS180
PXRA master regulator of drug clearance
Metabolism
Multi-Drug Resistance?
Excretion
Taxol & TaxotereRelated chemotherapeutic agents
Efficacy: Breast & Ovarian CancersActivity: Microtubule Stabilization
OAc
OHO
OAcOO
O
OOH
O
N
O
OH
H
Taxol
OH
OHO
OAcOO
O
OOH
O
NO
O
OH
H
Taxotere
Taxol vs TaxotereTaxotere does NOT activate hPXR
Taxol
GAL-hPXRFo
ld A
ctiv
atio
n
Taxotere
50
40
30
20
10
0
0 5 10 15 20 25 30
Taxane(mM)
Taxol vs TaxotereTaxotere does NOT induce drug clearance
MetabolismMetabolism
0
1
2
3
4
Taxol Taxotere-
P-G
lygo
prot
ein
Activ
ity
EffluxEfflux
Intestine
Taxol Taxotere-0
25
50
75
100
125
Cyp
3A4
Activ
ity3’
p-O
H T
axol
Pro
duct
ion
Hepatocytes
Taxo
l Ef
flux
Rat
e
HIV Protease Inhibitors & PXRRitonavir is a PXR ligand
TransfectionTransfectionhPXR
0
200
400
600
800
1000
1200
1400
|
UnlabeledProtease Inhibitor
hPXR+
[3 H]-SR12813
Hyp
erfo
rinR
itona
vir
Saqu
inav
ir
Nel
finav
irIn
dina
vir
Ligand BindingLigand BindinghPXRhPXR
Spec
ific
Bind
ing
(cpm
)
SNS
NN N N N O
O
O OH
O
Ritonavir
StructureStructurehPXR
1
4
7
10
13
16
19GAL-hPXR
Fold
Act
ivat
ion
Rifa
mpi
ci
Rito
navi
Saqu
inav
ir
Nel
finav
irIn
dina
vir
Protease Inhibitor
rn
Steroid & Xenobiotic Receptor (PXR/SXR)PXR ligands are Cyp3A4 substrates
Function: Master regulator of drug & xenobiotic clearance
Function: Master regulator of drug & xenobiotic clearance
Expression: Liver & IntestineExpression: Liver & Intestine
Target Genes: MDR1, MRP2, OATP2 Cyp3A4, Cyp2C8, Cyp2BGSTa1, UGT1A, CARAminolevulinate synthase (ALAS), Por
Target Genes: MDR1, MRP2, OATP2 Cyp3A4, Cyp2C8, Cyp2BGSTa1, UGT1A, CARAminolevulinate synthase (ALAS), Por
PXRE
RXRRXR PXRPXR
Ligands: Common Drugs & XenobioticsEndogenous Ligands?Dietary Supplements?
Ligands: Common Drugs & XenobioticsEndogenous Ligands?Dietary Supplements?
Triol: a Potent PXR Agonist Cyp3A4 & PXR utilize common sterol substrates
HO OH
OH
NoneNone PCNPCN0
1
2
3
4
5
Rep
orte
r Act
ivity
Transfection AssayMouse PXR
Transfection AssayMouse PXR
6
TriolTriol
EC503 µM
5β-cholestane-3α,7α,12α-Triol55ββ--cholestanecholestane--33αα,7,7αα,12,12αα--TriolTriol
Cyp3A4Cyp3A4
HO OH
OHOHOH
55ββ--cholestanecholestane--33αα,7,7αα,12,12αα,25,25--TetrolTetrol
Cyp27 KO: Triol Accumulation & PXR Activation
OH OH
OH
Cyp27Cyp27TriolTriol Cholic AcidCholic Acid
0
25
50
75
Min
utes
Tribromoethanol Sleep Time
Tribromoethanol Tribromoethanol Sleep TimeSleep Time
Cyp27Cyp27--//--
WTWT
Cyp2CCyp2C
OATP2OATP2
GAPDHGAPDH
Cyp3A11Cyp3A11
+/+ -/-Cyp27:
Hepatic Target GenesHepatic Target Genes
PXRSpecies-specific responses
Human PXRHuman PXR Mouse PXRMouse PXR
29
1
5
9
13
17
21
25
29
Fold
Act
ivat
ion
PCN
PCN
PCN
PCN
Rifa
mpi
cin
Rifa
mpi
cin
Rifa
mpi
cin
Rifa
mpi
cin
33
25
1
5
9
13
17
d Ac
tivat
ion 21
Fol
Widespread Use of Dietary Supplements
Widespread Use of Dietary Supplements
Widespread Use of Dietary Supplements
Future Research Needs & ResourcesPredict and prevent herbal-drug interactions
Require comprehensive study of herbal meds for effects on:Require comprehensive study of herbal meds for effects on:• PXR activation• Endogenous PXR ligands• Expression of genes involved in drug clearance• Activity of P450 enzymes and transporters• Drug clearance in humanized mice• Human trials using non-invasive measures of drug clearance• Similar studies on related receptor CAR
Teach clinicians & patientsTeach clinicians & patients• Natural product ≠ Safety • Medical histories should document use of drug supplements • Create online database• Modify supplement use is counterindicated• FDA-like regulation? Standardize potency, efficacy, safety?
Explanation of Explanation of interindividualinterindividual differences in drug clearance?differences in drug clearance?• Polymoprphisms in PXR• Polymorphisms in CAR
Ex- Lab MembersJenny ChenHaibo Wang
Hye-Dong Yoo
Research AssociatesMing Fan
Michael HoKevin Hollister
Min LinIrina Ianculescu
Karol RostamianiEric Wang
Ex- Lab MembersJenny ChenHaibo Wang
Hye-Dong Yoo
Research AssociatesMing Fan
Michael HoKevin Hollister
Min LinIrina Ianculescu
Karol RostamianiEric Wang
CoH CollaborationsTom Balon
Larry SowersTim Synold
Mark ShermanJohn Termini
Outside CollaborationsR. Chandraratna (Allergan)
S. Erickson (UCSF)G. Salen (UMDNJ)V. LaMorte (UCI)
M. Stemerman (UCR)J. Shyy (UCR)
F. Sladek (UCR)
CoH CollaborationsTom Balon
Larry SowersTim Synold
Mark ShermanJohn Termini
Outside CollaborationsR. Chandraratna (Allergan)
S. Erickson (UCSF)G. Salen (UMDNJ)V. LaMorte (UCI)
M. Stemerman (UCR)J. Shyy (UCR)
F. Sladek (UCR)
City of HopeCity of Hope
FellowsGregg Van CittersIsabelle Dussault
Lily LaiShyamali MallickKohei ShimadaCorinne Solier
Xiaolei XuDonna Yu
Xiaohui Yuan
FellowsGregg Van CittersIsabelle Dussault
Lily LaiShyamali MallickKohei ShimadaCorinne Solier
Xiaolei XuDonna Yu
Xiaohui Yuan
National Center for Complementary and Alternative MedicineNational Institutes of Health
National Center for Complementary and Alternative MedicineNational Institutes of Health