Stopping cancer cell movement; questioning dark matter; a Year of Light

Media bulletins

Stopping cancer cells from moving – by blocking a widespread enzyme, Sydney’s Centenary Institute researchers have shown they can slow down the movement of cells and potentially stop tumours from spreading and growing. More below.

Sceptical physicists – is dark matter really necessary, do we need 17 fundamental particles to explain the Universe, and are we heading down the wrong fusion path. Here are some of the contrary views presented at the national physics congress last week.

Plus physics and light. 2015 is the International Year of Light and in the run up to New Year’s Eve fireworks we’ll have astronomers, physicists, and others available to talk about light:

  • From the Nobel Prize to Bunnings – how the invention of the blue LED is transforming the way homes and offices are lit
  • Light revealing your first hug, how coeliac disease kicks off, and how our immune systems work
  • Light empowering refugee women and children
  • First light – the great ignition, and the search for the dark matter that holds our galaxy together.

And we’ve also got some curious physics stories from last week’s Art of Physics congress

More on these stories below.

Sonar: could maths and science have shortened WW1?

The First World War saw the stuttering beginnings of modern military physics. In secret, the British were operating the largest military science project to date. The first combined military-civilian research project, a team of a thousand scientists including Nobel laureates Ernest Rutherford and William Bragg, was working on a sonar system to detect enemy submarines. Working sonar rigs were being attached to British ships by the end of the war, by which time 5000 ships and 15,000 lives had been lost to German U-boats. University of Queensland physicist Timo Nieminen has studied the physics of WWI, both successful and unsuccessful, and links from this to the much more resourced, more famous Manhattan Project of WWII.

Laser tracking of carbon-belching cattle

Livestock belch out around ten per cent of Australia’s total greenhouse gas emissions. There are ways to reduce this, but how do you measure their success? New technology designed to measure methane emissions from cattle out in the field could provide the answer. Working with CSIRO’s Livestock Methane Research cluster, Brian Orr (from Macquarie University) and his colleagues are developing laser-based instruments that can be used in cattle yards and open ranges to detect the concentration of methane and ammonia molecules in air, as well as other gases that could be useful indicators of animal health and air quality.

Finding airports on planets circling distant stars

Research astronomer and skilled science communicator Lisa Harvey-Smith from CSIRO is part of the team working towards Australia’s part in the Square Kilometre Array (SKA) radio telescope. She also actively supports women in science and is a keen ultramarathon runner, currently in training for ANZAC Ultra 2015—a six-day, 435 km race on the Canberra Centenary Trail. She’s also mentored astronomy activities at the remote Pia Wadjari Community School in WA.

Lisa is project scientist for the prototype for the SKA—the Australian SKA Pathfinder (ASKAP)—which is being put through its paces prior to going into action next year. ASKAP, with 36 radio dishes, and the SKA, with many more receivers again, will produce pictures of the universe covering a greater area and looking deeper into space than is currently possible. So sensitive that it would be able to detect an airport radar on a planet 50 light years away, SKA will also show us stars and galaxies forming in the very early universe.

Conference media contacts
Niall Byrne 0417 131 977
Errol Hunt 0423 139 210
Margie Beilharz 0415 448 065

Challenging the orthodoxy in dark matter, dark energy, fusion and more

Good science happens when clever people ask insightful questions. Some papers at the national physics congress in Canberra last week took on their colleagues—asking penetrating questions of mainstream science.

Defence against the dark parts

In theory, dark matter and dark energy together comprise 95 per cent of the Universe. But no-one’s ever seen them. No-one’s quite sure what they’re made of, nor how they work. Do they exist at all?

The textbooks say they must exist—to account for observations such as the rapid spin of the outer reaches of our galaxy and the accelerating expansion of the Universe. But ‘inventing’ something to fix the equations makes some physicists nervous. And there are other theories that also explain these observed phenomena—without the need for dark matter and dark energy.

A handful of physicists at the national physics congress in Canberra last week favour other explanations of the basic building blocks of the Universe:

What if space itself expanded more in areas of higher matter density, and less elsewhere. This fairly simple starting assumption has some startling results: the speed of light for example—constant in an area with a given matter density (such as in the region of our own Solar System)—would effectively slow down in regions where matter is less dense. In the outer Galaxy, the reduced density of stars and resulting slower speed of light would make it appear that stars moved faster out there. Physicist Peter Lamb, of Deakin University, explains that the model similarly accounts for the other ‘requirements’ that persuaded physicists we needed dark matter and dark energy, while accounting for missing antimatter, and reconciling quantum mechanics with general relativity

Too many particles

Do we really need the 17 proposed fundamental elementary particles of the ‘standard model’? Vivian Robinson says we might only need one: our universe could be made up of many different orientations of just one particle—the simple photon—moving either in straight lines as energy, or spinning in tight circles as matter. Vivian’s theory fits measurements for atomic and nuclear structure, the lack of dark energy in our galaxy, and relativity, without requiring 17 fundamental particles.

Are we heading down the wrong path for a fusion future

The fuel used by most fusion energy researchers is a mix of deuterium-tritium, two isotopes of hydrogen. To ignite, this mix requires very high temperatures (around 100 million degrees C) and massive compression, achieved using very strong magnetic fields, which also confine the reaction once underway. During the reaction, short-term neutron radiation poses operational issues, and tritium waste remains radioactive for a number of decades.

Heinrich Hora is working on something quite different. He proposes to use a different (proton-boron) fuel, which can be directly ignited using short-burst lasers to accelerate plasma blocks. This alternative fusion method, recognised since the 1970s, had been discounted by most researchers because of the high energies needed to ignite the fuel, and higher magnetic fields needed to contain the reaction. But recent developments in both short-pulse, high-power lasers and generation of ultra-strong magnetic fields have now made it feasible. Compared with the deuterium-tritium method, it would promise elimination of dangerous short-term neutron radiation, no hazardous tritium to dispose of, lower energy required to initiate the reaction, and cheaper construction costs. Because it uses already-proven technology, it could be a far faster route to commercial fusion energy than is being pursued elsewhere, with commercial fusion possibly available in ten years. Steven Haan, an expert in nuclear fusion at Lawrence Livermore National Laboratory in California, has called block ignition “the fastest route to fusion energy”.

You want how many dimensions?

Even the physics Congress’s plenary guests don’t always agree. Like most cosmologists, Lisa Randall thinks the Universe requires eleven space-time dimensions—or perhaps ten. But Lawrence Krauss says any theory that requires that many dimensions to work properly is probably too complicated to be true.

If cells can’t move…cancer can’t growCentenary Logo

By blocking a widespread enzyme, Centenary researchers have shown they can slow down the movement of cells and potentially stop tumours from spreading and growing.

Using a new super-resolution microscope they’ve been able to see single molecules of the enzyme at work in a liver cancer cell line. Then they’ve used confocal microscopes to see how disrupting the enzyme slows down living cancer cells.

The enzyme is DPP9 (dipeptidyl peptidase 9) which the researchers at the Centenary Institute and the Sydney Medical School were first to discover and clone, in 1999. Ever since they’ve been studying what it does, with a view to its possible use as a cancer drug target.

“It was exciting to be able to watch the enzyme at work and then block DPP9, and see the cells slow down,” says A/Prof Mark Gorrell from Centenary’s Molecular Hepatology unit. “This gives us our clearest evidence yet that this enzyme will be a good cancer drug target.”

“What this work has shown us is that this enzyme is absolutely critical to cell movement, and without cell movement, tumors can’t grow or spread,” says Gorrell of the work, published in the leading European cell biology journal BBA Molecular Cell Research.

Using the recently acquired super-resolution microscope, Ms Hui (Emma) Zhang—one of Gorrell’s PhD students—determined where individual fluorescently tagged DPP9 molecules were located inside cells. She found that DPP9 lies on the microtubules that play a significant role in intracellular transport and in cell migration.

When cells were stimulated to move, Zhang discovered DPP9 accumulates at the leading edge of the moving cell. DPP9 was also associated with the adhesion protein complex that glues the cell to the external matrix though which it moves, acting as an anchor point to pull the cell along. When the action of DPP9 was inhibited in cells, such movement and adhesion diminished.

“DPP9 is looking more and more like a cancer drug target. But at present we have no specific inhibitors for it, even though chemists have been trying for some years to make one.” he said. “We need to throw more resources at this problem.”

During the past 15 years, Gorrell has been unveiling the properties of DPP9, which belongs to a small family of four enzymes specialised in cleaving other proteins. Members of this family modify and regulate proteins for many important functions inside and outside of cells. DPP4, for instance, is already the basis of a leading drug treatment for diabetes. DPP4 inhibitors are worth about $6 billion a year and comprise about a quarter of the diabetes drug market.

“The roadblock to developing a specific inhibitor for DPP9 has been that it is very similar physically, but not functionally, to DPP8. It has been hard to distinguish between the two chemically,” Gorrell says. He is now working on determining and publishing differences between the two enzymes, which should help chemists target their efforts better.

“This is our first paper to be generated using this new microscope, which we acquired in collaboration with Sydney University with the help of the Ramaciotti Foundation,” the Executive Director of the Centenary Institute, Prof Mathew Vadas AO says. “It is a great illustration of the value of the latest microscope imaging technologies to medical research.”

Full release, backgrounder, photos and video at:

For interviews and more information:
• Toni Stevens, Science in Public on 0401 763 130 or
• Mark Gorrell, Molecular Hepatology unit, Centenary Institute on 0419 933 474 or
• Serena Stewart, Centenary Institute on 0466 166 878 or

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