The role of sirtuin 3 in the differential pro-oxidant effects of (-)-epigallocatechin-3-gallate in oral cells Ling Tao Advisor: Joshua D. Lambert, Ph.D. Lab of Food and Disease Prevention Department of Food Science The Pennsylvania State University
The role of sirtuin 3 in the differential pro- oxidant effects of (-)-epigallocatechin-3- gallate in oral cells Ling Tao Advisor: Joshua D. Lambert, Ph.D.
Jan 03, 2016
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The role of sirtuin 3 in the differential pro-
oxidant effects of (-)-epigallocatechin-3-
gallate in oral cells
Ling TaoAdvisor: Joshua D. Lambert, Ph.D.Lab of Food and Disease PreventionDepartment of Food ScienceThe Pennsylvania State University
We have no conflicts of
interest to declare
for this study.
Oral cancer has high morbidity and mortality
42,440 new cases and 8,390 deaths expected
Major risk factors: smoking & excessive alcohol
American cancer society, 2014
Dietary intervention may be an important and effective approach to reduce oral cancer burden
EGCG is the most abundant polyphenol in green tea
Green tea has cancer preventive effects
Green tea is a rich source of catechins
1.25% (w/v) green tea has ~1.5 mM EGCG
Jankun et al, 1997; Muto et al., 2001; Yang et al., 2009
Yang et al., 1998; Lambert and Elias, 2010; Li et al., 2010
There is increasing evidence showing EGCG’s pro-oxidant activities under certain conditions
EGCG produced reactive oxygen
species (ROS) in cell culture medium
and inside the cells
EGCG induced dose-dependent
oxidative stress, DNA damage, and
apoptosis in xenograft lung tumor
EGCG selectively induced mitochondrial ROS and cell apoptosis in oral cancer cells
Tao et al., 2013; Tao and Lambert, 2014 (unpublished)
(B)
(C)
SCC-25 HGF-10
5
10
15 ControlEGCG
**
TU
NE
L p
osi
tive
(%
)
(D)
(A)
SCC25: human oral squamous carcinoma cellsHGF-1: human gingival fibroblast cells
Sirtuin 3 is an important regulator of mitochondrial redox balance
Sirtuin 3 (SIRT3) is mainly localized
in mitochondria and is an NAD+-
dependent deacetylase
SIRT3 mitigates mitochondrial ROS
The transcription of SIRT3:
ERRα: estrogen-related receptor α
PGC-1α: peroxisome proliferator-
activated receptor gamma, coactivator
1 alpha
SIRT3
FOXO3aCYC GPX
SOD2
CAT
PRX3
mtROS
Bause and Haigis, 2013; Chen et al., 2014
Will SIRT3 play an important
role in the differential pro-
oxidant effects of EGCG?
EGCG induced differential changes of SIRT3 expression and activity in oral cells
SCC-25 HGF-10.0
0.2
0.4
0.6
0.8
1.0
1.2 0 h
1 h3 h
6 h*** *
**
mR
NA
leve
l of
SIR
T3
(A)
SCC-25 HGF-10.0
0.2
0.4
0.6
0.8
1.0
1.2 0 h
6 h12 h
24 h
SIRT3
*** **
Rel
ativ
e P
rote
in L
evel
(B)
1h 12 h0
20
40
60
80
100 ControlEGCG
*
**
**SCC-25
SIR
T3
ac
tiv
ity
(co
un
ts/
g p
rote
in)
1h 12 h0
20
40
60
80
100 ControlEGCG
*
**
**
HGF-1
SIR
T3
ac
tiv
ity
(co
un
ts/
g p
rote
in)
(C)
1h 12 h0
20
40
60
80
100 ControlEGCG
*
**
**SCC-25
SIR
T3
acti
vity
(co
un
ts/
g p
rote
in)
1h 12 h0
20
40
60
80
100 ControlEGCG
*
**
**
HGF-1
SIR
T3
acti
vity
(co
un
ts/
g p
rote
in)
EGCG regulates SIRT3 transcription in oral cancer cells through estrogen-related receptor α (ERRα)
SCC-25 HGF-10.0
0.2
0.4
0.6
0.8
1.0
1.2 0 h
1 h3 h
6 h
*
mR
NA
lev
el o
f E
RR
(A)
SCC-25 HGF-10.0
0.2
0.4
0.6
0.8
1.0
1.2 0 h
6 h12 h
24 h
ERR
****
**
Rel
ativ
e P
rote
in L
evel
ERRα
GAPDH
0 6 12 24 h 0 6 12 24 h
SCC-25 HGF-1
(B)
00.
5 1 3 60.0
0.5
1.0
1.5 SCC-25
Time (h)
Nu
clea
r/cy
top
lasm
icE
RR
rat
io
**
**
00.
5 1 3 60.0
0.5
1.0
1.5
2.0 HGF-1
Time (h)
Nu
clea
r/cy
top
lasm
icE
RR
rat
io
*
ERRα
Histone3
0 0.5 1 3 6 h
SCC-25 HGF-1
0 0.5 1 3 6 h
ERRα
GAPDH
NC
(C)
EGCG differentially regulated SIRT3-modulated antioxidant defense genes
0.0
0.5
1.0
1.5
* *
Rel
ativ
e fo
ld c
han
ge
0.0
0.5
1.0
1.5
2.0
2.5
**
**
**
0
1
2
3
4
5
****
**
0.0
0.5
1.0
1.5
Rel
ativ
e fo
ld c
han
ge
0.0
0.5
1.0
1.5
2.0
0.0
0.5
1.0
1.5
Time (h)
Rel
ativ
e fo
ld c
han
ge
*
*
0.0
0.5
1.0
1.5
2.0
2.5
Time (h)
*
0.0
0.5
1.0
1.5
** **
Rel
ativ
e fo
ld c
han
ge
**
SCC-25 HGF-1
GPX1
SOD2
CYC
FOXO3a
Ptrend<0.05 Ptrend<0.01
Ptrend<0.01
Ptrend=0.06
Ptrend=0.28
Ptrend=0.60
Ptrend=0.76 Ptrend<0.05
0.0
0.5
1.0
1.5
* *
Rel
ativ
e fo
ld c
han
ge
0.0
0.5
1.0
1.5
2.0
2.5
**
**
**
0
1
2
3
4
5
****
**
0.0
0.5
1.0
1.5
Rel
ativ
e fo
ld c
han
ge
0.0
0.5
1.0
1.5
2.0
0.0
0.5
1.0
1.5
Time (h)
Rel
ativ
e fo
ld c
han
ge
*
*
0.0
0.5
1.0
1.5
2.0
2.5
Time (h)
*
0.0
0.5
1.0
1.5
** **
Rel
ativ
e fo
ld c
han
ge
**
SCC-25 HGF-1
GPX1
SOD2
CYC
FOXO3a
Ptrend<0.05 Ptrend<0.01
Ptrend<0.01
Ptrend=0.06
Ptrend=0.28
Ptrend=0.60
Ptrend=0.76 Ptrend<0.05
0.0
0.5
1.0
1.5
* *
Rel
ativ
e fo
ld c
han
ge
0.0
0.5
1.0
1.5
2.0
2.5
**
**
**
0
1
2
3
4
5
****
**
0.0
0.5
1.0
1.5
Rel
ativ
e fo
ld c
han
ge
0.0
0.5
1.0
1.5
2.0
0.0
0.5
1.0
1.5
Time (h)
Rel
ativ
e fo
ld c
han
ge
*
*
0.0
0.5
1.0
1.5
2.0
2.5
Time (h)
*
0.0
0.5
1.0
1.5
** **
Rel
ativ
e fo
ld c
han
ge
**
SCC-25 HGF-1
GPX1
SOD2
CYC
FOXO3a
Ptrend<0.05 Ptrend<0.01
Ptrend<0.01
Ptrend=0.06
Ptrend=0.28
Ptrend=0.60
Ptrend=0.76 Ptrend<0.05
0.0
0.5
1.0
1.5
* *
Rel
ativ
e fo
ld c
han
ge
0.0
0.5
1.0
1.5
2.0
2.5
**
**
**
0
1
2
3
4
5
****
**
0.0
0.5
1.0
1.5
Rel
ativ
e fo
ld c
han
ge
0.0
0.5
1.0
1.5
2.0
0.0
0.5
1.0
1.5
Time (h)
Rel
ativ
e fo
ld c
han
ge
*
*
0.0
0.5
1.0
1.5
2.0
2.5
Time (h)
*
0.0
0.5
1.0
1.5
** **
Rel
ativ
e fo
ld c
han
ge
**
SCC-25 HGF-1
GPX1
SOD2
CYC
FOXO3a
Ptrend<0.05 Ptrend<0.01
Ptrend<0.01
Ptrend=0.06
Ptrend=0.28
Ptrend=0.60
Ptrend=0.76 Ptrend<0.05
In conclusion:
Acknowledgement
People and facilities
Dr. Joshua Lambert and lab members
Dr. Jack (John) P. Vanden Heuvel
Penn State Genomics Core Facility &
Microscopy Facility
Funding
American Institute for Cancer Research grant (to JDL)
Graduate Student Competitive Grant from the Pennsylvania State University College of Agricultural Sciences (to LT).
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