Abstract Book 2010 - CIMT Annual Meeting

006 Bernard | Therapeutic vaccination
Investigating the impact of autophagy modulation on dendritic
cell cancer vaccines
Dannie Bernard 1 , Julian J. Lum 2 , Yonghong Wan 1 and Jonathan L. Bramson 1
1 Department of Pathology and Molecular Medicine, McMaster University, Hamilton, Ontario, L8N 3Z5, Canada
2 Deeley Research Center, BC Cancer Agency, Vancouver Island, British Columbia, V8R 6V5, Canada
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Autophagy has been linked to extended survival
when cells are faced with cellular stress. Ex-vivo
derived dendritic cells (DCs) undergo substantial
stress upon antigen loading and in-vivo delivery
and the importance of autophagy in protecting
DCs from these stresses is poorly understood.
We have employed 2 strategies to investigate the
impact of autophagy on DC vaccines. In the first
case, we employed rapamycin as an inducer of autophagy
in an effort to precondition the DCs prior
to infection with recombinant adenovirus (Ad)
and recombinant vesicular stomatitis virus (VSV).
Kinetic analyses showed that rapamycin was effective
at inhibiting its target mTOR within 5 hours of
treatment and the inhibition was maintained for at
least 24 hours post-transduction. Preconditioning
of DCs with rapamycin did not affect infectivity,
as measured by GFP expression, nor did it affect
maturation, defined by MHC II, CD40, CD86, IL-12
and TNF-a expression. However, we noted a 10-fold
reduction in type I interferon secretion following
VSV transduction, but not Ad transduction. We
are currently conducting in-vivo experiments with
rapamycin-preconditioned DC vaccines and results
will be discussed at the meeting. In the second
case, we have investigated the role of basal autophagy
in the context of DC vaccination. We have
crossed ATG5fl/fl mice with CD11c-Cre mice to generate
conditional knockout mice in which DCs are
autophagy-deficient. Results obtained thus far from
in-vitro phenotyping experiments of virally trans-
duced DCs indicate that autophagy deficiency does
not significantly impact maturation of the cells.
The importance of autophagy following delivery of
DC vaccines still remains to be determined. This
work was supported by grants from CIHR, OCRN
and TFF.