Molecular and behavioral exploration of orofacial hypersensitivity in a model of oxaliplatin-chemotherapy

induced acute neuropathy

Laura POUPON, 1ère année de thèseU1107 – Pharmacologie fondamentale et clinique de la douleur

Directeur : Pr. A. Eschalier

9ème Symposium National du Réseau Recherche sur la Douleur22 et 23 mars 2013

Oxaliplatin chemotherapy-induced neuropathy

Therapeutic effects

Adverse effects

Used in colorectal cancer chemotherapy

Inhibits DNA replication by platinum adduct formation

90% of patients develop acute neuropathy

Cold hypersensitivity

Numbness at both extracephalic and cephalic territories

Dose reduction to limit neuropathic symptoms

Cephalic territory

Extracephalic territory

Oxaliplatin (Eloxatin®)

Platinum-based antineoplasic

DRG

Cold hyperalgesia

Mechanical hypersensitivity

Existing extracephalic results in mice

Mice modelClinical symptoms

Descoeur et al., 2011

Mice ion channels transcriptional expression

Existing extracephalic results in mice

DRG

Descoeur et al., 2011

Correlation between oxaliplatin-induced cold hypersensitivity and remodelling of ion channel expression in nociceptors

Clinical symptoms

DRG

Differences between cephalic and extracephalic sensory systems

TG

C-fibers

Sensory systems

A-fibers

Caudalis

Cephalic

?

DRG

Extracephalic

Aim of the study

• Development of adapted orofacial behavioral tests

• Assessment of ion channel transcriptional plasticity at the TG level

• Genetic or pharmacological validation of ion channels as targets of interest ?

Are there behavioral and molecular differences between the cephalic and the extracephalic territories in a murine model of oxaliplatin chemotherapy-induced neuropathy

?

Material & Methods

Mice model

Single i.p. injection of oxaliplatin (6mg/kg)

Peak pain behavior at D4

Daily measures of pain scores from D0 to D4

Day

D0 D1 D2 D3 D4

Behavioral tests

Caudalis -TG

HIC(pERK)

qPCR(ion channels)

Oral cold perception in WT mice

J-3 J0 J1 J2 J3 J40

1

2

3

4

5

* *

Wat

er c

onsu

mpti

on (m

L)

Oxaliplatin

Vehicle pERK

Cold water aversion test

Vehicle Oxaliplatin 6 mg/kg

Oral cold Hypersensitivity

D4 - Caudalis

D0 D1 D2 D3 D4

3h3h 3h 3h 3h 3h

4 - 6°C

30 min0

50

100

150

200

250VehOxa

Cutaneous cold and Mechanical perception in WT mice

Scor

e

Vehicle Oxaliplatin 6 mg/kg

J-3 J0 J1 J2 J3 J40

1

2

3

4

*****

Brush test

Response to dynamic mechanical stimulation

5 consecutive strokes

Groo

min

g (s

) ****

J-3 J0 J1 J2 J3 J412

14

16

18Vehicle Oxaliplatin 6 mg/kg

Acetone test

Daily measure of grooming behavior

On the upper lip area skin surface

Cutaneous cold Hypersensitivity Mechanical hypersensitivity

Ion channels plasticity in DRG and TGqPCR

Extracephalic (DRG)

Cephalic (TG)

Vehicle Oxaliplatin

Cold sensors : TRPM8 and TRPA1

J0 J40

4

8

12

16

Groo

min

g (s

)

Scor

e

NSNS

J0 J40

1

2

3

4

****

Vehicle Oxaliplatin 6 mg/kg

TRPM8 -/- mice

Oxaliplatin fail to induce cold hypersensitivity andpreserve mechanical pain symptoms in TRPM8 null mice

Vehicle TRPA1 Antagonist(HC030031)

Groo

min

g (s

)

TRPA1 implication in cold hypersensitivity

WT mice

Scor

e

**NS

qPCR Acetone test Brush test

J0 J41

5

9

13

J0 J40

1

2

3

4

*****

NS

***

Groo

min

g (s

)

Scor

e

HCN channels :

J0 J40

1

2

3

4

5 ****

Scor

e

NSNaClIvabradine NaClIvabradine

Vehicle

Oxaliplatin

Acetone test Brush test

Groo

min

g (s

)

J0 J412

14

16

18 * **

Ivabradine (Procoralan®)

Non-specific HCN antagonist

Reversion of cold hypersensitivityNo effects on mechanical sensibility

Oxaliplatin

Vehicle HCN1

Xx40

Conclusion

CEPHALIC cold and mechanical hypersensitivity induced by oxaliplatin

Differencies between cephalic and extracephalic territories at both molecular and pharmacological levels

Extracephalic (DRG) Cephalic (TG)

TRPM8 → +   - →   +  - 

TRPA1  ↗ -   +  →  +  -HCN1 - HCN2 ↗  +   - ↗↗   + - 

Perspectives

Impact of oxaliplatin on functional TG neurons? Ca2+ imaging

Involvement of K2P TREK and TRAAK channels?Use of other KO mice (TREK2, TREK1-TRAAK)

Cephalic and extracephalic behavioral, molecular & pharmacological consequences of repeated oxaliplatin injections

Short term

Long term

Acknowledgements

Project realized in association with

Institut de génomique fonctionnelle (Montpellier) Anne PIZZOCCARO, Emmanuel BOURINET

Inserm U1107 (Clermont Ferrand)Neurobiologie de la douleur trigéminale

Amélie DESCHEMEAKER, Radhouane DALLELLaboratoire de pharmacologie fondamentale et clinique de la douleur

Vanessa PEREIRA, Maryse CHALUS, Alain ESCHALIER, Jérôme BUSSEROLLES

Thank you for your attention

Vandewauw et al., 2013

Channels expression

TRPA

1

TRPM

8

Cold water aversion test

Results at 20°C

20 °C

Vehicle x20

Oxaliplatin

pERK

HCN Channels

Postea et al., 2011