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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

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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Tao et al., 2013; Tao and Lambert, 2014 (unpublished)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).