Vascular Disruption and Vascular Disruption and Vascular Disruption and Vascular Disruption and Antiangiogenesis Antiangiogenesis Dietmar W. Siemann, Ph.D. Dietmar W. Siemann, Ph.D. University of Florida University of Florida University of Florida University of Florida
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Vascular Disruption andVascular Disruption andVascular Disruption and Vascular Disruption and AntiangiogenesisAntiangiogenesis
Dietmar W. Siemann, Ph.D.Dietmar W. Siemann, Ph.D.University of FloridaUniversity of FloridaUniversity of FloridaUniversity of Florida
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
Wh D C Th i F il?Wh D C Th i F il?Why Do Cancer Therapies Fail?Why Do Cancer Therapies Fail?
•• Both Both local recurrenceslocal recurrences and and distant metastasesdistant metastasesare significantly affected by tumor are significantly affected by tumor progressionprogressionand tumorand tumor pathophysiologypathophysiologyand tumor and tumor pathophysiologypathophysiology..
•• These factors are critically impacted by the These factors are critically impacted by the initiationinitiation andand maintenance/expansionmaintenance/expansion of aof a tumortumorinitiationinitiation and and maintenance/expansionmaintenance/expansion of a of a tumor tumor blood vessel networkblood vessel network..
Vascular Disruption and AntiangiogenesisVascular Disruption and AntiangiogenesisMaintenance Maintenance
and and E iE iExpansionExpansion
InitiationInitiationInitiationInitiation
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
Hypoxia and acidity are inducers Hypoxia and acidity are inducers
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
proangiogenic factors outweigh proangiogenic factors outweigh i i i fi i i f
endostatinendostatinangiostatinangiostatini t fi t f
antiangiogenic factorsantiangiogenic factors
interferonsinterferonsothersothers VEGFVEGF
PDGFPDGFFGFFGFILIL 88ILIL--88othersothers
New vessel developmentNew vessel development
•• VEGF is considered the most powerful proangiogenic factor in tumorsVEGF is considered the most powerful proangiogenic factor in tumors•• Associated with tumor growth rate, vessel density, metastasesAssociated with tumor growth rate, vessel density, metastases
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
Inhibition of VEGF signalingInhibition of VEGF signalingInhibition of VEGF signalingInhibition of VEGF signaling
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
•• Inhibitors of VEGFInhibitors of VEGF--associated signaling demonstrate associated signaling demonstrate antitumor efficacy in a wide variety of rodent tumor models antitumor efficacy in a wide variety of rodent tumor models and human tumor xenografts including renal, colorectal, KS, and human tumor xenografts including renal, colorectal, KS, and sarcoma.and sarcoma.
30
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Caki-1
Median
20
al s
ize
(day
s
17
25-75%10-90%
10
to 5
x in
itia
8.5
14
0
Tim
e
Treatment: daily (M-F) x 2
Control BMS58266450 mg/kg
BMS582664100 mg/kg
Treatment
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
•• But But –– antianti--angiogenic therapy efficacy in solid tumors has angiogenic therapy efficacy in solid tumors has b d tb d t dd h th i lik l t li i th th i lik l t li i tbeen modest been modest –– and and –– such therapies are unlikely to eliminate such therapies are unlikely to eliminate the entire tumor cell population on their own.the entire tumor cell population on their own.
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
V l Di ti A tV l Di ti A tVascular Disrupting AgentsVascular Disrupting Agentselicit a tumor cell death cascade due to prolonged ischemiaelicit a tumor cell death cascade due to prolonged ischemia
Shape change and detachment
VE-cadherin disengagement
TumorTumor Damage toDamage to Vessel occlusionVessel occlusionneovasculatureneovasculature
ggestablished vesselestablished vessel and tumor necrosisand tumor necrosis
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
VDA T t t EffiVDA T t t EffiVDA Treatment EfficacyVDA Treatment EfficacyControl VDA treated
•• Vascular disrupting Vascular disrupting agents effectively agents effectively eliminate large areas eliminate large areas ggof solid tumors.of solid tumors.
•• Particularly areasParticularly areas•• Particularly areas Particularly areas typically resistant to typically resistant to conventional anticonventional anti--cancer therapies.cancer therapies.cancer therapies.cancer therapies.
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
•• But But –– cells surviving at the tumor periphery aggressively promote cells surviving at the tumor periphery aggressively promote l i til i ti dd h th i lik l t li i th th i lik l t li i tneovascularization neovascularization –– and and –– such therapies are unlikely to eliminate such therapies are unlikely to eliminate
the entire tumor cell population on their own.the entire tumor cell population on their own.
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
C bi i V l Di t d St t iC bi i V l Di t d St t iCombining Vessel Directed StrategiesCombining Vessel Directed Strategies
•• VDAs effectively VDAs effectively eliminate large areas eliminate large areas of tumorsof tumors 0.8
•• VDAs plus AIs VDAs plus AIs provide more provide more effective tumor effective tumor therapy than either therapy than either
0 20 40 60 80 100 120
Time (days)
0.0KSY-1
treatment alonetreatment alone
Siemann and Shi,Siemann and Shi, IJROBPIJROBP, 2004, 2004
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
40ys
)
30
size
( day
24
33
20
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itia l
s 24
19
10
Tim
eto
5
6
14.512
Control Bevacizumab CA4P OXi4503 + BevBev +0
T 6
BevBevCA4P OXi4503
Treatment
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
C l iC l iConclusionConclusion
•• Therapeutic strategies relying on single biologic Therapeutic strategies relying on single biologic agent targeting approaches may be beneficial but agent targeting approaches may be beneficial but their ultimate impact on treatment efficacy is likelytheir ultimate impact on treatment efficacy is likelytheir ultimate impact on treatment efficacy is likely their ultimate impact on treatment efficacy is likely to be limited. to be limited.
•• AIs and VDAs can modify conventional antiAIs and VDAs can modify conventional anti--cancercancerAIs and VDAs can modify conventional antiAIs and VDAs can modify conventional anti cancer cancer therapy therapy –– but better cytotoxics are needed.but better cytotoxics are needed.
•• The application of combined The application of combined Biologic Targeting Biologic Targeting StrategiesStrategies needs to be considered.needs to be considered.
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
Nucleus XX–– LigandLigand–– ReceptorReceptor–– TK signalTK signal
Antisense
gg–– MessageMessage
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
Si l P th T ti CSi l P th T ti CSingle Pathway Targeting ConcernsSingle Pathway Targeting Concerns
•• The complexity of neovascularization pathways The complexity of neovascularization pathways implies that disrupting only a single aspect of implies that disrupting only a single aspect of angiogenesis probably will not sufficeangiogenesis probably will not sufficeangiogenesis probably will not suffice.angiogenesis probably will not suffice.
•• Multiple RTKs are coMultiple RTKs are co activated in tumors andactivated in tumors and•• Multiple RTKs are coMultiple RTKs are co--activated in tumors and activated in tumors and redundant inputs drive and maintain redundant inputs drive and maintain downstream signaling, thereby limiting the downstream signaling, thereby limiting the efficacy of therapies targeting single RTKs.efficacy of therapies targeting single RTKs.
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
M lti l P th T tiM lti l P th T tiMultiple Pathway TargetingMultiple Pathway Targeting
•• Possible StrategiesPossible Strategies–– Single molecule affecting several pathways Single molecule affecting several pathways
RAD001 T i li )RAD001 T i li )–– RAD001, Temsirolimus)RAD001, Temsirolimus)–– Vasculature (VDAs, AIs)Vasculature (VDAs, AIs)
•• MetastasesMetastasesA i i (VEGFA i i (VEGF i TKI ‘ ib ’)i TKI ‘ ib ’)–– Angiogenesis (VEGF Angiogenesis (VEGF –– various TKI ‘nibs’)various TKI ‘nibs’)
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
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40
50
60
ber
37.1
ZD6474
20
30
Vess
el n
um
37.1
32
20.1
45 KHT sarcoma
Control 25 mg/kg 50 mg/kg
Treatment
0
10
25
30
35
40
ng C
olon
ies
24
Treatment
•• Combining strategies Combining strategies
10
15
20
25N
umbe
r of L
un 24
1714.5
10
g gg gthat target angiogenesis that target angiogenesis and cell invasion may and cell invasion may inhibit metastases inhibit metastases formationformation
Control ZD647425 mg/kg
AZ053010 mg/kg
ZD6474+ AZD0530
Treatment
0
5formation.formation.
Vascular Disruption and AntiangiogenesisVascular Disruption and Antiangiogenesis
C l iC l iConclusionsConclusions
•• Future therapeutic strategies should seek to Future therapeutic strategies should seek to develop “combination biologic therapy” develop “combination biologic therapy” targeting multiple intervention points and/ortargeting multiple intervention points and/ortargeting multiple intervention points and/or targeting multiple intervention points and/or functionally related pathways.functionally related pathways.
•• AndAnd –– to apply such combinations of biologic to apply such combinations of biologic agents in conjunction with conventional agents in conjunction with conventional anticancer treatments.anticancer treatments.