Plenary
Lecture
Platinum Drugs, Still Essential in our Fight Against
Cancer
Associate Professor
Janice Aldrich-Wright
Nanoscale Organisation and Dynamics Group
School of Biomedical and Health Sciences
College of Health & Science
University of Western Sydney
Locked Bag 1797, Penrith South DC
N.S.W. 1797 Australia
E-mail:
J.Aldrich-Wright@uws.edu.au
Abstract:
Introduction
In order to overcome the toxic
side-effects of cisplatin and its
analogues and the acquired
resistance many cancers develop to
platinum treatment1 my group has
been developing two new families
of platinum based anticancer
agents, as well as new drug
delivery vehicles (DDVs).
Metallointercalators
We have developed a family of over
70 structurally related
metallointercalators based on
phenanthroline and phenanthroline-derivatives
and chiral ancillary ligands which
display cytotoxicity at levels up
10-fold lower than cisplatin in
many different cancer cells lines
which are sensitive or resistance
to cisplatin.2-5 In in vivo trials
the maximum tolerated dose was
found to be around 16 mg/Kg
compared to cisplatin (6 mg/kg).
We are currently conducting
further in vitro and in vivo
trials which include efficacy
trials in rats with HCT8 colon
cancer and nude mice with human
breast, lung and colon tumour
xenographs.
Sequence Selective Agents
We have been developing a range of
platinum-based drugs which include
ligands that are capable of
binding to specific DNA
sequences.6-7 These agents bind to
their target sequences with
greater affinity than other
sequences, are able to prevent RNA
synthesis in vitro and unwind DNA
helices by up to 13o. We are
currently synthesising more
soluble forms of these cationic
complexes that we hope will have
sufficient sequence specificity to
selectively bind to telomere
regions or mutant p53 genes of
DNA.
Drug Delivery Vehicles (DDV)
Cationic lipids have been widely
studied for their ability to
deliver genes and DNA vaccines for
therapeutic purposes. These lipids
provide a DNA delivery vehicle
into the cell and protect DNA from
extracellular degradation. In the
1990’s, CSIRO developed a platform
drug and gene delivery technology
by using a very common buffer,
2-amino-2-hydroxymethyl-propane-1,3-diol
(Tris).8-10 It was recognised that
Tris could provide a
straightforward yet novel method
for attaching one, two or three
fatty acids to amino acids or
peptides to alter their
physicochemical properties. Tris
cationic lipids (DDV) offer
chemical flexibility, readily
allowing generation of a range of
conjugates with one, two or three
different fatty acyl substituents,
which can then be tailored, for
different functions. Although
there has been a lot of interest
in the application of cationic
lipids for gene delivery, their
usage for delivery of anticancer
drugs has remained relatively
unexplored.
Brief Biography of the Speaker:
Associate Professor Janice
Aldrich-Wright; (B.App.Sc.,
University of Technology Sydney;
Ph.D, Macquarie University) is
currently based at the University
of Western Sydney. She is a Royal
Australian Chemical Institute
Fellow and her research has been
the subject of patent application
and more than sixty peer reviewed
publications. Over the past 20
years she has established a
research group at UWS that focuses
on metal complex-DNA interactions
with numerous local and
international collaborations.
Importantly, she has established
anticancer compounds which operate
under a mode of action different
to current clinical alternatives.
Innovative bioinorganic molecular
design, elegant synthesis and the
biophysical and biological testing
of these compounds are at the
heart of her research drive.
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