A team led by Dr David Huang from The Walter and Eliza Hall Institute
of Medical Research (WEHI) has made significant advances in understanding
the signalling pathways that affect the behaviour of cells. This discovery
may assist in the eventual development of more refined therapies to
combat a range of cancers, including blood-borne cancers such as lymphomas.
Under normal conditions of health, a process called apoptosis - or
programmed cell death - ensures that old, damaged or unnecessary
cells die at the right time. This process is essential to maintain
a balance of normal cells required for good health.
Scientists have been aware that the balance between two competing
classes of proteins - pro-survival and anti-survival - determines
whether a cell lives or dies. It has been understood that the pro-survival
proteins keep cells alive. When a cell is damaged or is no longer required,
the anti-survival proteins act upon the pro-survival proteins to trigger
cell death. If this normal and healthy program is faulty, then damaged
cells persist and continue to divide uncontrollably, creating rogue
collections of cells or cancer. Therefore, an attractive way to kill
cancer cells may be to tip the balance against the pro-survival proteins,
such as by harnessing the action of the anti-survival proteins. However,
a potential danger of using anti-survival cells to kill cancer cells
is the collateral damage to normal cells.
The WEHI team has discovered that the process is not as simple as "pro-
versus anti-survival." Instead, they discovered that some of
the anti-survival proteins have highly selective action on particular
pro-survival proteins. This discovery of the cell's complexity
will be useful in the eventual development of more specific cancer
drugs that have fewer side effects.
Dr Huang explains that the discovery about how cell death proceeds
is already having a practical impact in the research laboratories of
WEHI. The techniques of Nuclear Magnetic Resonance (NMR) and X-ray
crystallography are being used to search for the detailed mechanism
that drives the selective action of anti-survival proteins. When this
is defined, it may help in developing more effective cancer treatments.
Other members of the discovery team are Dr Lin Chen, Mr Simon Willis,
Dr Andrew Wei, Professor Jerry Adams, Professor Peter Colman, Dr Brian
Smith, Dr Jamie Fletcher, Dr Mark Hinds (all from WEHI) and Dr Catherine
Day from the Biochemistry Department, University of Otago, Dunedin,
New Zealand.
The research was funded by the NHMRC; Cancer Council
Victoria; the US-based Leukemia and Lymphoma Society; the Australian
Cancer Research Foundation (ACRF); the Viertel Foundation; the Leukaemia
Foundation of Victoria; and the Marsden Fund (New Zealand).
The research paper is published in the prestigious journal Molecular
Cell of 4 February 2005. A related article describing the structure
of one of the pro-survival proteins, determined by Dr Catherine Day
and Dr Mark Hinds, appears in the 11 February 2005 issue of the Journal
of Biological Chemistry.
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