Immunogenetherapy of tumours as a Neoadjuvant to Surgery

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Immunogenetherapy of tumours as a Neoadjuvant to
Surgery

• Marie Claire Cronin
• Supervisors Dr. Mark Tangney, Prof. G.C.
  OSullivan
• Department of Surgery

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OVERVIEW

• Surgery in Cancer Treatment
• Minimal Residual Disease
• Immunogenetherapy of Solid Tumours
• Neoadjuvant Immunogenetherapy
• Clinical Potential

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After excision, even when a scar has formed,
none the less the disease has returned.

• In cancer the oncogenic potential of
  postoperative micrometastases is related to
  immunological responses in the primary tumour
• This association between intratumoural
  inflammatory reaction,clearance of
  micrometastases prognosis indicates a systemic
  antitumour reaction that confers a survival
  advantage after removal of the primary tumour

Murphy et al. Am J Gastro 2000 95(12) 3607-3614
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Hypothesis

• By immunogenetherapy of the primary tumour
  might it be possible to establish a systemic
  immune response to effectively control minimal
  residual disease without necessarily eliminating
  the primary cancer.
• Aims
• Specifically would genetic manipulation of the
  primary tumour to express the B7-1 co-stimulatory
  molecule and secrete GM-CSF induce durable
  anti-tumourigenic immune responses in a
  neoadjuvant setting.

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Experimental Methods

• Treatment in vivo of growing JBS (fibrosarcoma)
  tumours in Balb-C mice by electroporation-immunoge
  netherapy
• Tumour Growth curves constructed
• Diameters measured on alternate days and volumes
  calculated (Vab2p/6)
• Excision of non-responding tumours at 7 days -
  systemic responses compared with controls
• Systemic responses determined via tumour
  rechallenge at 21 days Tumourigenic dose JBS
• Demonstration of Clinical Potential -
  Electrochemotherapy

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Potential Immunogenic Mechanisms Plasmid
Coding for GM-CSF and B7-1
Membrane localisation sequence
Secretory sequence
hEF-1a/ HTLV
CMV
GM-CSF/B7-1 Plasmid
B7-1
GM-CSF

• CpG sequences of plasmid activate dendritic
  cells within tumour
• B7-1 expression on tumour cell surface provides
  a costimulatory signal to lymphocytes and with
  MHC class 1 molecules allows direct antigen
  presentation by tumour cell and arming of
  lymphocytes at tumour level
• GM-CSF cytokine provides chemotactic,
  proliferative, maturation and survival signals
  within tumour

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Electropermeabilisation

• Exposure of cells to electric fields of high
  intensity and short duration induces a transient
  and reversible permeabilisation of the cell
  membrane which facilitates the entry into the
  cytosol of macromolecules such as bleomycin or
  plasmid DNA.

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Immunogenetherapy of Solid Tumours in vivo
Technique

• General anaesthetic Halothane
• Gene construct intralesional injection
• Electric pulses electropermeabilisation

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Growth Rate of Non-Responders
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SURGERY

• Surgical Resection of Non-Responders (9/24) one
  week post IGT
• Halothane Anaesthesia Oxygen
• Wide local excision with 0.5 cm margin around
  tumour
• Wound closed with 4.0 prolene sutures
• Rechallenge at 21 days

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Survival on JBS Rechallenge Non-Responders after
Excision
100 Survival (plt0.01)
N9
N6
N12
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Electrochemotherapy (ECT)
Successful clinical application of
electroporation in the treatment of cutaneous
recurrence in a patient with progressive disease
refractory to conventional therapies.
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Feasibility

• Trained Surgeons available
• ESOPE ECT LA Midazolam
• one dr one nurse
• Ethical
• Cost
• Machine Cliniporator
• - Electrodes,
• - DNA Plasmid
• Actually easy to adapt to a
  clinical setting !!!!

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Of Mice and Men The Future of Immunogenetherapy

• Straightforward Treatment
• without antigen isolation or ex vivo cell
  modification
• feasible in most surgical departments.
• Ethics approval for gene therapy trials
• - patients available who require surgery anyway
  
• - Could have major impact on disease free
  survival, quality of
• life as well as overall survival
• The future of Surgical Oncology?
• - The future of cancer therapy lies in targeted
  local therapy with
• systemic immune upregulation for the
  control of minimal
• residual disease.

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Immunogenetherapy of Solid TumoursConclusions

• Suitable Treatment for Neoadjuvant setting
  immune responses in lt1 week.
• Effective Systemic Network evoked irrespective of
  response of Primary - active against minimal
  disease state in all
• Effective and Safe eliminates Primary Tumour in
  gt60
• Use in the neoadjuvant setting raises response
  rate from 60 to 100

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Acknowledgements

• Dr. Mark Tangney
• Dr. John Larkin
• Ruth Gleeson
• Prof. G.C. OSullivan
• All Staff of Biological Services Unit who
  looked after the mice for the duration of the
  experiments.