2019 Sc ie ntific Re tre a t F rida y, April 26, 2019 Disc o ve - - PowerPoint PPT Presentation

2019 Sc ie ntific Re tre a t

F rida y, April 26, 2019 Disc o ve ry Wo rld Pa vilio n

Carmen Bergom, MD, PhD Department of Radiation Oncology Medical College of Wisconsin

UT I L I ZI NG GE NE T I C MODE L S F OR CARDI O-ONCOL OGY: GE T T I NG T O T HE HE ART OF T HE MAT T E R

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RADI AT I ON-I NDUCE D CARDI OT OXI CI T Y

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• Radiation therapy received by >50% of all cancer patients

– Includes breast cancer patients; >3.5 million U.S. breast cancer survivors in U.S.

• Radiation improves cancer-specific survival, but heart radiation

can cause long-term toxicity

• Relative risk of cardiovascular events in early left-sided breast

cancer can be 1.3 or greater

– Higher risk with other cardiac risk factors, with cardiotoxicity systemic therapy, and higher doses due to involved lymph nodes – Linear relationship between mean heart dose and major cardiovascular events

RADI AT I ON-I NDUCE D CARDI OT OXI CI T Y

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• Relative risk of fatal cardiovascular events is 2-7 in

Hodgkin’s Lymphoma patients who receive radiation

• Relative risk of fatal cardiovascular events is 2-6+ in

childhood cancer survivors receiving higher cardiac radiation doses

RADI AT I ON-I NDUCE D CARDI OT OXI CI T Y

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• Radiation also plays an integral role in treating

advanced lung cancer

• Recent studies show that radiation-induced

cardiotoxicity could manifest within 2 years of radiation for lung cancer

• In lung cancer patients, mortality correlates with

mean heart dose, or with the percent of the heart receiving 5 Gy, 30 Gy, or 50 Gy

GOAL : I MPROVE T HE RAPE UT I C RAT I O

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Adapted from https://www.healthxchange.sg/

ST RAT E GI E S T O MI NI MI ZE RADI AT I ON- I NDUCE D CARDI OT OXI CI T Y

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• Mounting evidence suggests that complex genetic

modifiers contribute to the risk of radiation-induced toxicity in cancer patients

– These genetic modifiers remain largely unknown and poorly understood

• We have developed the first genetic model to identify

heritable modifiers of radiation-induced cardiotoxicity

RE SE ARCH PL AN

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Identify Biomarkers that Predict Normal Tissue Toxicity Cardiac Irradiation in Genetic Animal Models Identify Novel Therapeutic Targets

Aim to identify factors that modify normal tissue side effects

RE SE ARCH PL AN

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Cardiac Irradiation in Genetic Animal Models

Aim to identify factors that modify normal tissue side effects

• Data suggested differences in the Sprague Dawley (SD) and

Brown Norway (BN) rat strain responses to heart radiation

• The PhysGen Database from MCW (pga.mcw.edu) gives

physiologic and pathologic parameters for SS (derived from SD) and BN inbred strains

• Cardiac phenotypes differed between SS and BN rat strains

SS AND BN RAT S USE D T O E XAMI NE NORMAL T I SSUE RADI AT I ON SE NSI T I VI T Y

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• Differences in SS and BN rats for post-ischemic infarct size

SS AND BN RAT CARDI AC PHE NOT YPE S

• Start by testing SS vs. BN radiation responses
• If differences in cardiac radiation sensitivity, consomic rat testing

(chromosome substitution) may be used to identify genetic variants

From pga.mcw.edu

*

*P<0.0001

RAT MODE L T O T E ST CARDI AC RADI AT I ON SE NSI T I VI T Y

• Treated to 24 Gy with 3 equal fields, AP

and 2 laterals, with 1.5 cm circular field

• Echocardiograms with strain analysis

performed to assess cardiac function

• Baseline
• 3 months
• 5 months

Image- Guided Heart Radiation

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Heart Total Lung Left Lung

Sagittal Axial Coronal 10 5 15 20 25 30 35 Structure Volume (%) 40 20 60 80 100 Dose (Gray)

RAT MODE L T O T E ST CARDI AC RADI AT I ON SE NSI T I VI T Y

• Adult female rats given 24 Gy

localized cardiac radiation

• Hearts harvested after 5 months
• SS rats had significant cardiac

hypertrophy (heart enlargement), while BN rats did not

• Hypertrophy occurs to compensate

for poorer function

• Consistent with hypothesis
• Consomic studies pursued

Reviewed consomic tumor studies and PGA to guide which consomic rats to initially test

SS RAT S MORE SE NSI T I VE T HAN BN RAT S T O RADI AT I ON-I NDUCE D CARDI OT OXI CI T Y

S S C o n t r o l ( n = 4 ) S S + R T ( n = 8 ) B N C o n t r o l ( n = 4 ) B N + R T ( n = 7 ) 2 4 6 h e a rt w e ig h t to b o d y ra tio (m g /g )

*

*P<0.05 Normalized Heart Weight

Selective Breeding BN SS

CONSOMI C RAT MODE L : SS.BN3

• Consomic rats

– Rats with same genetic makeup except one chromosome substituted from another strain

Chromosome 3 from BN strain

• Chrom. 3

SS.BN3

SS/ BN/ SS.BN3 RAT CARDI AC PHE NOT YPE S

• Start by testing SS vs. SS.BN3 consomic cardiac radiation responses
• Hypothesis: SS and SS.BN3 rats will respond differently to heart radiation

From pga.mcw.edu

• Differences in SS and BN post-ischemic infarct size

*P<0.0001

* **

CONSOMI C RAT MODE L T O T E ST CARDI AC RADI AT I ON SE NSI T I VI T Y

SS.Chr3 Consomic (SS.BN3) SS

Image- Guided Heart Radiation

• Assess SS.BN3 versus SS normal heart tissue radiation sensitivity
• Start with 24 Gy x 1
• Obtain echocardiograms at 0, 3, and 5 months

*P < 0.05

• Amount of fluid in the lungs (pleural effusions) increased in

the SS rats after radiation

• Fluid can be present due to inflammation or heart failure

SS RAT HE ART S MORE SE NSI T I VE T O RADI AT I ON

SS RAT S E XPE RI E NCE MORT AL I T Y AF T E R L OCAL I ZE D CARDI AC RADI AT I ON

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NO SI GNI F I CANT DI F F E RE NCE S I N E CHOCARDI OGRAMS F ROM UNT RE AT E D RAT S

SS – No Radiation SS.BN3 – No Radiation

SS RAT HE ART S E XHI BI T SYST OL I C DYSF UNCT I ON VI A E CHOCARDI OGRAM

• The SS heart exhibits decreased contractility after radiation

SS – 5 Months Post-Radiation SS.BN3 – 5 Months Post-Radiation

• Echocardiogram data

SS RAT HE ART S E XHI BI T SYST OL I C DYSF UNCT I ON VI A E CHOCARDI OGRAM

End Systolic Volume

Time After Radiation

S S .B N 3 S S

SS SS.BN3

0 .0 0 .2 0 .4 0 .6 0 .8

E S V m l/k g

0 Mo 3 Mo 5 Mo

†

†P < 0.01

• Echocardiogram data

SS RAT HE ART S E XHI BI T SYST OL I C DYSF UNCT I ON VI A E CHOCARDI OGRAM

Time After Radiation

S S .B N 3 S S

SS SS.BN3

0 .0 0 .2 0 .4 0 .6 0 .8

E S V m l/k g

0 Mo 3 Mo 5 Mo

†

1 3 5 7 0 8 0 9 0 1 0 0

M o n th s p o s t R T E F %

Ejection Fraction

†P < 0.01 †P < 0.01

SS SS.BN3

†

Months Post-RT

End Systolic Volume

SS RAT S HAVE L OWE R ST RAI N ON E CHOCARDI OGRAM

Left Ventricular Radial Strain

†P < 0.01 #P < 0.001 Time After Radiation

† #

S S .B N 3 S S

SS SS.BN3

Thickening of Myocardium (%)

I NCRE ASE D MYOCARDI AL NE CROSI S I N SS RAT S 5 MONT HS AF T E R RADI AT I ON

S S S S .B N 3

1 2 3 4

Necrosis Score SS SS-BN3

*

*P < 0.05

SS control SS.BN3 control SS + RT SS.BN3 + RT

I NCRE ASE D F I BROSI S I N SS RAT S 5 MONT HS AF T E R RADI AT I ON

SS SS.BN3 TRICHROME STAINING

SS RAT HE ART S MORE SE NSI T I VE T O 5X9 GY F RACT I ONAT E D RADI AT I ON

1 2 3 4 5 50 100

Months Post RT Percent survival

P=0.039

SS SS.BN3

0/10 4/11

Percent Survival

Months Post RT

2 4 6

Heart to Body Ratio (mg/g)

SS Control (N=5) SS + RT (N=8) SS.BN3 Control (N=6) SS.BN3 + RT (N=10)

P=0.037

• Male rats also exhibit similar patterns, with SS more sensitive

than SS.BN3

HE ART GE NE E XPRE SSI ON CHANGE S AF T E R RADI AT I ON

• RNA-seq gene expression data

– From left ventricle at 1 week after radiation

• Chrom. 3

Candidates Z-Score SS SS.BN3 SS SS.BN3

CARDI OT OXI CI T Y F ROM A VARI E T Y OF CANCE R T HE RAPI E S

• Chemotherapeutic and targeted therapies can cause cardiac

dysfunction

• Doxorubicin and other anthracyclines have dose-dependent cardiac risk
• Many breast cancer and lymphoma patients receive radiation heart

exposure after receiving doxorubicin

• Doxorubicin and radiation cause higher risk of cardiac dysfunction than single

modality treatment

• Are the SS rats more sensitive to doxorubicin-induced cardiotoxicity?

SS RAT S MORE SE NSI T I VE T O DOXORUBI CI N T HAN SS.BN3 RAT S

• Adult female rats treated with doxorubicin
• 2 mg/kg weekly I.P. for 8 weeks; causes heart changes similar to clinical changes
• Echocardiograms revealed worse cardiac function in the SS rats, similar to

cardiac radiation

• Increased end diastolic volume (EDV) and end systolic volume (ESV) in SS rats after

doxorubicin

0.0 0.2 0.4 0.6 0.8

ESV ml/kg

*

Doxorubicin SS SS.BN3

ESV (ml/kg)

*

Doxorubicin

1 2 3 4

EDV ml/kg

EDV (ml/kg)

SS SS.BN3

• Many distinct measures of cardiac damage are worse n SS vs.

SS.BN3 rats

• Male and female rats
• Both large single fraction and fractionated (9 Gy x 5)
• Utilize genetic mapping to identify variants in chromosome 3

enhancing radiosensitivity

SUMMARY AND NE XT ST E PS

SS heart SS.BN3 heart

Radiation Radiation

• Narrow down region of interest on rat chromosome 3

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CONGE NI C MAPPI NG

CONGE NI C RAT PANE L

• Adult female rats given

24 Gy localized cardiac radiation

• Hearts harvested after 5

months

• Echocardiograms with

strain analysis performed at 0, 3, and 5 months

SS SS.BN3 CG.1 CG.2 CG.3 CG.4

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QUE ST I ON:

Which of the SS.BN3 congenic rats will respond similarly to SS with respect to cardiac irradiation?

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SS AND SS.BN3 + CONGE NI C RAT S

SS heart SS.BN3 heart

Radiation Radiation

Radiation CG.1 heart Radiation CG.2 heart Radiation CG.3 heart Radiation CG.4 heart

? ? ? ?

CG.4 RAT S HAVE SI MI L AR NORMAL I ZE D HE ART WE I GHT T O SS RAT S POST

• RT

Normalized Heart Weight

CG.4 HAVE I NCRE ASE D PL E URAL E F F USI ONS SI MI L AR T O SS RAT S POST

• RADI

AT I ON

CG.4 RAT S HAVE DE CRE ASE D RADI AL ST RAI N SI MI L AR T O SS RAT S POST

• RADI

AT I ON

Left Ventricular Radial Strain

25 MB Region

SS SS.BN3 CG.1 CG.2 CG.3 CG.4

• 25 MB region contains 331 genes, 131 expressed genes,

and 93 genes differentially expressed after RT

CONGE NI C MAPPI NG CONCL USI ONS T HUS F AR

DI F F E RE NT I AL L Y E XPRE SSE D GE NE S I N T HE 25 MB RE GI ON

Heart Pygb Tasp1 Tcf15 Id1 Ccm2l Procr Myh7b Myl9 Cd40

Mitochondria Jph2 Acss1 Uqcc1 Map1lc3a Ndufaf5 Mgme1 Acss2 Nfs1 Tomm34 LOC100910944 RGD1566320 Notch Slc35c2 Jag1 Pofut1 Cbfa2t2 Other Epb41l1 Csnk2a1 Rbm39 Rprd1b Ncoa5 Ube2c Src Mmp24 Tgif2 Cst3 Apoptosis/Autophagy Wisp2 Mybl2 Tp53inp2 Id1 Tp53inp2

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• Honokiol
• Used in Chinese medicine > 1,000 years
• Active extract from magnolia bark
• Activator of Sirt3
• Preserves mitochondria and protects doxorubicin-induced

cardiomyopathy in mice

T E ST I NG CANDI DAT E PAT HWAYS

C Koentges et al., 2016 Front Cardiovasc Med

+ RT injury? Pillai VB, Kanwal A, et al., Oncotarget (2017)

• The Sirt3 and mitochondrial

function pathways were top differentially expressed pathways in the SS vs. SS.BN3 hearts after radiation

• We are examining enhancing

these pathways to protect against radiation

T E ST I NG WHE T HE R HONOK I OL PROT E CT S AGAI NST RADI AT I ON

Hypothesis: Honokiol protects rats against radiation-induced cardiotoxicity, and mito- honokiol will protect to a greater extent

Pan et al., iScience 2018

This will be tested later this year

• Mito-honokiol targets honokiol to the mitochondria
• Mito-honokiol shows enhanced activity to inhibit cancer cell growth (Ming You,

MD, PhD & Balaraman Kalyanaraman, PhD)

SUMMARY AND CONCL USI ONS

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• Genetic variants on rat chromosome 3 are important

for cardiac radiation injury

• Also true for doxorubicin injury
• Mitochondrial- and Sirtuin-related pathways may be important
• First genetic model of radiation-induced cardiotoxicity
• Consomic panels used to identify genetic variants

influencing radiation and other treatment toxicities

• Also identifies critical downstream pathways

WHY I AM A CANCE R RE SE ARCHE R AND PHYSI CI AN

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• My uncle (died age 41, colon cancer)
• My aunt (breast cancer, age 44)
• My grandmother (breast cancer, age 80)
• My uncle (prostate cancer, age 57)
• My great aunt (breast cancer, age 74)
• My cousin (breast cancer, age 46)
• My cousin (prostate cancer, age 50)
• My close friend (multiple myeloma, age 63)
• Another friend (died age 40, breast cancer)
• My patients (too many to count)
• Future family members and friends affected by cancer

ACK NOWL E DGE ME NT S

• Rachel Schlaak
• Anne Frei

Small Animal Echocardiography Core

Bergom Laboratory

• Dr. Michael Flister

Department of Radiation Oncology Joshi Laboratory Medhora Lab/Radiation Core O’Meara Laboratory Vasquez-Vivar Laboratory Funding Support

• MCW Cancer Center
• Mary Kay Foundation
• Susan G. Komen Foundation
• CTSI
• Nancy Laning Sobczak, Ph.D., Breast Cancer Award
• MCW Cardiovascular Center
• Michael H. Keelan, Jr., M.D., Research Foundation Grant
• Dr. Paula North

Rui Laboratory Kalyanaraman Laboratory

T HANK YOU!

I f yo u wa nt to g o fa st, g o a lo ne . I f yo u wa nt to g o fa r, g o to g e the r.

– Afric a n Pro ve rb

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