Tonight, find the large spiral galaxy next door. As shown on the chart at the top of this post, the Great Square of Pegasus serves as a great jumping off point for finding the Andromeda galaxy, otherwise known as M31. The Great Square sparkles over your eastern horizon at nightfall and travels westward across the sky throughout the night. For some idea of the Great Square’s size, extend your hand an arm’s length from your eye. You’ll see that any two Great Square stars are farther apart than the width of your hand.
As seen from mid-northern latitudes, the Square of Pegasus looks like a baseball diamond whenever it resides in the eastern sky. Imagine the farthest star to the left – Alpheratz – as the third-base star. An imaginary line drawn from the first-base star through Alpheratz points in the general direction of the Andromeda galaxy.
The Andromeda galaxy and two satellite galaxies as seen through a powerful telescope. To the eye, the galaxy looks like a fuzzy patch. It’s an island of stars in space, much like our Milky Way. Image Credit: NOAO
If it’s dark enough, you’ll see two streamers of stars flying to the north (or left) of the star Alpheratz. To some people, this grouping of stars looks like a bugle or a cornucopia. Along the bottom streamer, star-hop from Alpheratz to the star Mirach. Draw an imaginary line from Mirach through the upper streamer star (Mu Andromedae), and go twice the distance. You’ve just located the Andromeda galaxy!
If you can’t see this fuzzy patch of light with the unaided eye, maybe your sky isn’t dark enough. Try binoculars! Or try going to darker sky.
View larger. | The Andromeda galaxy (right side of photo) as seen by EarthSky Facebook friend Ted Van at a Montana campsite in mid-August 2012. Thank you, Ted!
Bottom line: If you can find the Great Square of Pegasus, then you can star-hop to the Andromeda galaxy.
Tonight, find the large spiral galaxy next door. As shown on the chart at the top of this post, the Great Square of Pegasus serves as a great jumping off point for finding the Andromeda galaxy, otherwise known as M31. The Great Square sparkles over your eastern horizon at nightfall and travels westward across the sky throughout the night. For some idea of the Great Square’s size, extend your hand an arm’s length from your eye. You’ll see that any two Great Square stars are farther apart than the width of your hand.
As seen from mid-northern latitudes, the Square of Pegasus looks like a baseball diamond whenever it resides in the eastern sky. Imagine the farthest star to the left – Alpheratz – as the third-base star. An imaginary line drawn from the first-base star through Alpheratz points in the general direction of the Andromeda galaxy.
The Andromeda galaxy and two satellite galaxies as seen through a powerful telescope. To the eye, the galaxy looks like a fuzzy patch. It’s an island of stars in space, much like our Milky Way. Image Credit: NOAO
If it’s dark enough, you’ll see two streamers of stars flying to the north (or left) of the star Alpheratz. To some people, this grouping of stars looks like a bugle or a cornucopia. Along the bottom streamer, star-hop from Alpheratz to the star Mirach. Draw an imaginary line from Mirach through the upper streamer star (Mu Andromedae), and go twice the distance. You’ve just located the Andromeda galaxy!
If you can’t see this fuzzy patch of light with the unaided eye, maybe your sky isn’t dark enough. Try binoculars! Or try going to darker sky.
View larger. | The Andromeda galaxy (right side of photo) as seen by EarthSky Facebook friend Ted Van at a Montana campsite in mid-August 2012. Thank you, Ted!
Bottom line: If you can find the Great Square of Pegasus, then you can star-hop to the Andromeda galaxy.
Click in to see more angles. | The black hole is seen nearly edgewise in this new visualization from NASA. The turbulent disk of gas around the hole takes on a double-humped appearance. The black hole’s extreme gravity alters the paths of light coming from different parts of the disk, producing the warped image. “What we see depends on our viewing angle,” NASA said. Image via NASA’s Goddard Space Flight Center/Jeremy Schnittman.
NASA released this new new visualization of a black hole this week, generated by astrophysicist Jeremy Schnittman, using custom software at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Schnittman’s areas of expertise include computational modeling of black hole accretion flows. That’s what you’re seeing in this visualization, the flow of material around a black hole as it might appear if you could see the hole up close (but not too close!), and from the side. Yes, black holes are black; no light can escape them. All the action is in the area immediately surrounding the hole, because the hole’s powerful gravity warps its surroundings, distorting our view, NASA said, “as if seen in a carnival mirror.” NASA explained on September 25, 2019:
The visualization simulates the appearance of a black hole where infalling matter has collected into a thin, hot structure called an accretion disk. The black hole’s extreme gravity skews light emitted by different regions of the disk, producing the misshapen appearance.
Bright knots constantly form and dissipate in the disk as magnetic fields wind and twist through the churning gas. Nearest the black hole, the gas orbits at close to the speed of light, while the outer portions spin a bit more slowly. This difference stretches and shears the bright knots, producing light and dark lanes in the disk.
Viewed from the side, the disk looks brighter on the left than it does on the right. Glowing gas on the left side of the disk moves toward us so fast that the effects of Einstein’s relativity give it a boost in brightness; the opposite happens on the right side, where gas moving away us becomes slightly dimmer. This asymmetry disappears when we see the disk exactly face on because, from that perspective, none of the material is moving along our line of sight.
Closest to the black hole, the gravitational light-bending becomes so excessive that we can see the underside of the disk as a bright ring of light seemingly outlining the black hole. This so-called “photon ring” is composed of multiple rings, which grow progressively fainter and thinner, from light that has circled the black hole two, three, or even more times before escaping to reach our eyes. Because the black hole modeled in this visualization is spherical, the photon ring looks nearly circular and identical from any viewing angle. Inside the photon ring is the black hole’s shadow, an area roughly twice the size of the event horizon — its point of no return.
Simulations and movies like these really help us visualize what Einstein meant when he said that gravity warps the fabric of space and time. Until very recently, these visualizations were limited to our imagination and computer programs. I never thought that it would be possible to see a real black hole.
Yet – as many recall – on April 10 of this year, the Event Horizon Telescope team released the first-ever image of a black hole’s shadow using radio observations of the heart of the galaxy M87.
It’s not a simulation. It’s not an artist’s concept. It’s the 1st radio image of a black hole, in the galaxy M87. This long-sought image – released April 10, 2019 by the Event Horizon Telescope team – has provided the strongest evidence to date for the existence of supermassive black holes. It opened a new window onto the study of black holes, their event horizons, and gravity. Image via Event Horizon Telescope Collaboration. Read more about this image.
Bottom line: For decades, astronomical theorists have told us that a black hole’s powerful gravity would warp the space around it. This new visualization from NASA’s Goddard Space Flight Center is the best yet at showing exactly how.
Click in to see more angles. | The black hole is seen nearly edgewise in this new visualization from NASA. The turbulent disk of gas around the hole takes on a double-humped appearance. The black hole’s extreme gravity alters the paths of light coming from different parts of the disk, producing the warped image. “What we see depends on our viewing angle,” NASA said. Image via NASA’s Goddard Space Flight Center/Jeremy Schnittman.
NASA released this new new visualization of a black hole this week, generated by astrophysicist Jeremy Schnittman, using custom software at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. Schnittman’s areas of expertise include computational modeling of black hole accretion flows. That’s what you’re seeing in this visualization, the flow of material around a black hole as it might appear if you could see the hole up close (but not too close!), and from the side. Yes, black holes are black; no light can escape them. All the action is in the area immediately surrounding the hole, because the hole’s powerful gravity warps its surroundings, distorting our view, NASA said, “as if seen in a carnival mirror.” NASA explained on September 25, 2019:
The visualization simulates the appearance of a black hole where infalling matter has collected into a thin, hot structure called an accretion disk. The black hole’s extreme gravity skews light emitted by different regions of the disk, producing the misshapen appearance.
Bright knots constantly form and dissipate in the disk as magnetic fields wind and twist through the churning gas. Nearest the black hole, the gas orbits at close to the speed of light, while the outer portions spin a bit more slowly. This difference stretches and shears the bright knots, producing light and dark lanes in the disk.
Viewed from the side, the disk looks brighter on the left than it does on the right. Glowing gas on the left side of the disk moves toward us so fast that the effects of Einstein’s relativity give it a boost in brightness; the opposite happens on the right side, where gas moving away us becomes slightly dimmer. This asymmetry disappears when we see the disk exactly face on because, from that perspective, none of the material is moving along our line of sight.
Closest to the black hole, the gravitational light-bending becomes so excessive that we can see the underside of the disk as a bright ring of light seemingly outlining the black hole. This so-called “photon ring” is composed of multiple rings, which grow progressively fainter and thinner, from light that has circled the black hole two, three, or even more times before escaping to reach our eyes. Because the black hole modeled in this visualization is spherical, the photon ring looks nearly circular and identical from any viewing angle. Inside the photon ring is the black hole’s shadow, an area roughly twice the size of the event horizon — its point of no return.
Simulations and movies like these really help us visualize what Einstein meant when he said that gravity warps the fabric of space and time. Until very recently, these visualizations were limited to our imagination and computer programs. I never thought that it would be possible to see a real black hole.
Yet – as many recall – on April 10 of this year, the Event Horizon Telescope team released the first-ever image of a black hole’s shadow using radio observations of the heart of the galaxy M87.
It’s not a simulation. It’s not an artist’s concept. It’s the 1st radio image of a black hole, in the galaxy M87. This long-sought image – released April 10, 2019 by the Event Horizon Telescope team – has provided the strongest evidence to date for the existence of supermassive black holes. It opened a new window onto the study of black holes, their event horizons, and gravity. Image via Event Horizon Telescope Collaboration. Read more about this image.
Bottom line: For decades, astronomical theorists have told us that a black hole’s powerful gravity would warp the space around it. This new visualization from NASA’s Goddard Space Flight Center is the best yet at showing exactly how.
Astronomers working with data from the space-based Chandra X-ray Observatory said this week (September 25, 2019) that they’ve located three supermassive black holes on a collision course. The system where this triple black hole merger is happening is called SDSS J0849+1114. It’s located about a billion light years from Earth. Telescopes on the ground and in space – including Chandra, Hubble, WISE and NuSTAR – captuted the scene, which scientists are calling:
… the best evidence yet for a trio of giant black holes.
So we haven’t seen many systems like this so far. And yet, astronomers believe, triplet collisions like this one play a critical role in how the biggest black holes grow over time. Ryan Pfeifle of George Mason University in Fairfax, Virginia is first author of a new paper in the peer-reviewedAstrophysical Journal, which describes these results (preprint here). He said:
We were only looking for pairs of black holes at the time, and yet, through our selection technique, we stumbled upon this amazing system. This is the strongest evidence yet found for such a triple system of actively feeding supermassive black holes.
These scientists’ statement described their process:
To uncover this rare black hole trifecta, researchers needed to combine data from telescopes both on the ground and in space. First, the Sloan Digital Sky Survey telescope, which scans large swaths of the sky in optical light from New Mexico, imaged SDSS J0849+1114. With the help of citizen scientists participating in a project called Galaxy Zoo, it was then tagged as a system of colliding galaxies.
Then, data from NASA’s Wide-field Infrared Survey Explorer (WISE) mission revealed that the system was glowing intensely in infrared light during a phase in the galaxy merger when more than one of the black holes is expected to be feeding rapidly. To follow up on these clues, astronomers then turned to Chandra and the Large Binocular Telescope in Arizona.
The Chandra data revealed X-ray sources — a telltale sign of material being consumed by the black holes — at the bright centers of each galaxy in the merger, exactly where scientists expect supermassive black holes to reside. Chandra and NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) also found evidence for large amounts of gas and dust around one of the black holes, typical for a merging black hole system.
Optical spectra contain a wealth of information about a galaxy. They are commonly used to identify actively accreting supermassive black holes and can reflect the impact they have on the galaxies they inhabit.
These astronomers said one reason it’s difficult to find a triplet of supermassive black holes is that the holes are likely to be shrouded in gas and dust, blocking much of their light. The infrared images from WISE, the infrared spectra from LBT and the X-ray images from Chandra bypass this issue, they said, because infrared and X-ray light pierce clouds of gas much more easily than optical light. Pfeifle explained:
Through the use of these major observatories, we have identified a new way of identifying triple supermassive black holes. Each telescope gives us a different clue about what’s going on in these systems. We hope to extend our work to find more triples using the same technique.
Another co-author on the new paper, Shobita Satyapal, also of George Mason, explained why this system is exciting to scientists:
Dual and triple black holes are exceedingly rare, but such systems are actually a natural consequence of galaxy mergers, which we think is how galaxies grow and evolve.
As you might expect, these scientists said, three supermassive black holes merging behave differently than just a pair:
When there are three such black holes interacting, a pair should merge into a larger black hole much faster than if the two were alone. This may be a solution to a theoretical conundrum called the ‘final parsec problem,’ in which two supermassive black holes can approach to within a few light-years of each other, but would need some extra pull inwards to merge because of the excess energy they carry in their orbits. The influence of a third black hole, as in SDSS J0849+1114, could finally bring them together.
Computer simulations have shown that 16% of pairs of supermassive black holes in colliding galaxies will have interacted with a third supermassive black hole before they merge. Such mergers will produce ripples through spacetime called gravitational waves. These waves will have lower frequencies than the National Science Foundation’s Laser Interferometer Gravitational-Wave Observatory (LIGO) and European Virgo gravitational-wave detector can detect. However, they may be detectable with radio observations of pulsars, as well as future space observatories, such as the European Space Agency’s Laser Interferometer Space Antenna (LISA), which will detect black holes up to one million solar masses.
Bottom line: Astronomers have discovered a system of 3 galaxies – called SDSS J0849+1114 – all orbiting each other a billion light years from Earth. Each galaxy contains a supermassive black hole, which are circling each other, about to collide.
Astronomers working with data from the space-based Chandra X-ray Observatory said this week (September 25, 2019) that they’ve located three supermassive black holes on a collision course. The system where this triple black hole merger is happening is called SDSS J0849+1114. It’s located about a billion light years from Earth. Telescopes on the ground and in space – including Chandra, Hubble, WISE and NuSTAR – captuted the scene, which scientists are calling:
… the best evidence yet for a trio of giant black holes.
So we haven’t seen many systems like this so far. And yet, astronomers believe, triplet collisions like this one play a critical role in how the biggest black holes grow over time. Ryan Pfeifle of George Mason University in Fairfax, Virginia is first author of a new paper in the peer-reviewedAstrophysical Journal, which describes these results (preprint here). He said:
We were only looking for pairs of black holes at the time, and yet, through our selection technique, we stumbled upon this amazing system. This is the strongest evidence yet found for such a triple system of actively feeding supermassive black holes.
These scientists’ statement described their process:
To uncover this rare black hole trifecta, researchers needed to combine data from telescopes both on the ground and in space. First, the Sloan Digital Sky Survey telescope, which scans large swaths of the sky in optical light from New Mexico, imaged SDSS J0849+1114. With the help of citizen scientists participating in a project called Galaxy Zoo, it was then tagged as a system of colliding galaxies.
Then, data from NASA’s Wide-field Infrared Survey Explorer (WISE) mission revealed that the system was glowing intensely in infrared light during a phase in the galaxy merger when more than one of the black holes is expected to be feeding rapidly. To follow up on these clues, astronomers then turned to Chandra and the Large Binocular Telescope in Arizona.
The Chandra data revealed X-ray sources — a telltale sign of material being consumed by the black holes — at the bright centers of each galaxy in the merger, exactly where scientists expect supermassive black holes to reside. Chandra and NASA’s Nuclear Spectroscopic Telescope Array (NuSTAR) also found evidence for large amounts of gas and dust around one of the black holes, typical for a merging black hole system.
Optical spectra contain a wealth of information about a galaxy. They are commonly used to identify actively accreting supermassive black holes and can reflect the impact they have on the galaxies they inhabit.
These astronomers said one reason it’s difficult to find a triplet of supermassive black holes is that the holes are likely to be shrouded in gas and dust, blocking much of their light. The infrared images from WISE, the infrared spectra from LBT and the X-ray images from Chandra bypass this issue, they said, because infrared and X-ray light pierce clouds of gas much more easily than optical light. Pfeifle explained:
Through the use of these major observatories, we have identified a new way of identifying triple supermassive black holes. Each telescope gives us a different clue about what’s going on in these systems. We hope to extend our work to find more triples using the same technique.
Another co-author on the new paper, Shobita Satyapal, also of George Mason, explained why this system is exciting to scientists:
Dual and triple black holes are exceedingly rare, but such systems are actually a natural consequence of galaxy mergers, which we think is how galaxies grow and evolve.
As you might expect, these scientists said, three supermassive black holes merging behave differently than just a pair:
When there are three such black holes interacting, a pair should merge into a larger black hole much faster than if the two were alone. This may be a solution to a theoretical conundrum called the ‘final parsec problem,’ in which two supermassive black holes can approach to within a few light-years of each other, but would need some extra pull inwards to merge because of the excess energy they carry in their orbits. The influence of a third black hole, as in SDSS J0849+1114, could finally bring them together.
Computer simulations have shown that 16% of pairs of supermassive black holes in colliding galaxies will have interacted with a third supermassive black hole before they merge. Such mergers will produce ripples through spacetime called gravitational waves. These waves will have lower frequencies than the National Science Foundation’s Laser Interferometer Gravitational-Wave Observatory (LIGO) and European Virgo gravitational-wave detector can detect. However, they may be detectable with radio observations of pulsars, as well as future space observatories, such as the European Space Agency’s Laser Interferometer Space Antenna (LISA), which will detect black holes up to one million solar masses.
Bottom line: Astronomers have discovered a system of 3 galaxies – called SDSS J0849+1114 – all orbiting each other a billion light years from Earth. Each galaxy contains a supermassive black hole, which are circling each other, about to collide.
The image at top, showing a campfire under the Milky Way, is by Ben Coffman Photography in Oregon. He wrote:
These good folks – co-workers from one of the resorts on Mt. Hood, if I remember correctly – let me take their photo on the beach near Cape Kiwanda [a state natural area near in Pacific City, Oregon]. They looked like they were having fun.
And so they do. What could be better than a beautiful night under the Milky Way? But did you know that every night of your life is a night under the Milky Way? By that we mean … every individual star you can see with the unaided eye, in all parts of the sky, lies within the confines of our Milky Way galaxy.
Our galaxy – seen in Ben’s photo above as a bright and hazy band of stars – is estimated to be some 100,000 light-years wide and only about 1,000 light-years thick. That’s why the starlit band of the Milky Way, which is still visible in the evening this month but will soon be less so, appears so well-defined in our sky.
Gazing into it, we’re really looking edgewise into the thin plane of our own galaxy:
This image is mosaic of multiple shots on large-format film. It comprises all 360 degrees of the galaxy from our earthly vantage point. Photography was done in Ft. Davis, Texas for the northern hemisphere shots and from Broken Hill, New South Wales, Australia, for the southern portions. Note the dust lanes, which obscure our view of some features beyond them. Image via Digital Sky LLC
In the image directly above – comprising all 360 degrees of the galaxy as seen from our earthly vantage point – note that the galaxy is brightest at its center, where most of the stars and a 4-million-solar-mass black hole reside. This image shows stars down to 11th magnitude – fainter than the eye alone can see.
If you’re standing under a clear, dark night sky, you’ll see the Milky Way clearly as a band of stars stretched across the sky on late summer evenings.
The band of the Milky Way is tough to see unless you’re far from the artificial lights of the city and you’re looking on a night when the moon is down.
If you do look in a dark country sky, you’ll easily spot the Milky Way. And, assuming you’re looking from the Northern Hemisphere, you’ll notice that it gets broader and richer in the southern part of the sky, in the direction of the constellations Scorpius and Sagittarius. This is the direction toward the galaxy’s center.
If you’re in the Southern Hemisphere, the galactic center is still in the direction of Sagittarius. But from the southern part of Earth’s globe, this constellation is closer to overhead.
The image below gives you an idea of the awesome beauty of our Milky Way galaxy in the night sky.
Bottom line: If you look in a dark country sky, you’ll easily spot the starlit band of our huge, flat Milky Way galaxy. Every star in our night sky that’s visible to the unaided eye lies inside this galaxy.
The image at top, showing a campfire under the Milky Way, is by Ben Coffman Photography in Oregon. He wrote:
These good folks – co-workers from one of the resorts on Mt. Hood, if I remember correctly – let me take their photo on the beach near Cape Kiwanda [a state natural area near in Pacific City, Oregon]. They looked like they were having fun.
And so they do. What could be better than a beautiful night under the Milky Way? But did you know that every night of your life is a night under the Milky Way? By that we mean … every individual star you can see with the unaided eye, in all parts of the sky, lies within the confines of our Milky Way galaxy.
Our galaxy – seen in Ben’s photo above as a bright and hazy band of stars – is estimated to be some 100,000 light-years wide and only about 1,000 light-years thick. That’s why the starlit band of the Milky Way, which is still visible in the evening this month but will soon be less so, appears so well-defined in our sky.
Gazing into it, we’re really looking edgewise into the thin plane of our own galaxy:
This image is mosaic of multiple shots on large-format film. It comprises all 360 degrees of the galaxy from our earthly vantage point. Photography was done in Ft. Davis, Texas for the northern hemisphere shots and from Broken Hill, New South Wales, Australia, for the southern portions. Note the dust lanes, which obscure our view of some features beyond them. Image via Digital Sky LLC
In the image directly above – comprising all 360 degrees of the galaxy as seen from our earthly vantage point – note that the galaxy is brightest at its center, where most of the stars and a 4-million-solar-mass black hole reside. This image shows stars down to 11th magnitude – fainter than the eye alone can see.
If you’re standing under a clear, dark night sky, you’ll see the Milky Way clearly as a band of stars stretched across the sky on late summer evenings.
The band of the Milky Way is tough to see unless you’re far from the artificial lights of the city and you’re looking on a night when the moon is down.
If you do look in a dark country sky, you’ll easily spot the Milky Way. And, assuming you’re looking from the Northern Hemisphere, you’ll notice that it gets broader and richer in the southern part of the sky, in the direction of the constellations Scorpius and Sagittarius. This is the direction toward the galaxy’s center.
If you’re in the Southern Hemisphere, the galactic center is still in the direction of Sagittarius. But from the southern part of Earth’s globe, this constellation is closer to overhead.
The image below gives you an idea of the awesome beauty of our Milky Way galaxy in the night sky.
Bottom line: If you look in a dark country sky, you’ll easily spot the starlit band of our huge, flat Milky Way galaxy. Every star in our night sky that’s visible to the unaided eye lies inside this galaxy.
A peculiar type of tumour, in an even more peculiar type of animal, could hold some clues to help scientists overcome immunotherapy resistance in humans.
Not many of us will have come across a Tasmanian devil in the wild – they’re only found on the island state of Tasmania. These creatures, similar in size to a small dog, are susceptible to a particular form of cancer, called devil facial tumour. And what’s unique about these tumours is that, unlike human cancers, they can be passed from devil to devil.
Tasmanian devils transmit the tumours by biting each other on the mouth, which they often do as part of a mating ritual. The cancer is almost always lethal, and with DFT now covering most of Tasmania, the future of devils in the wild is uncertain. Teams at the University of Tasmania Menzies Institute for Medical Research and School of Medicine are working to understand devil facial tumour in an attempt to conserve the population.
Serendipitously, this work could help cancer scientists understand why some people don’t respond to immunotherapy.
But first, we need to come back to the UK.
Cancer resistance and immunotherapy
In Cambridge, Dr Marian Burr and her colleagues were trying to understand why some immunotherapies were not getting the responses they were anticipating.
Immunotherapy treatments can work in lots of different ways, but they all aim to harness our immune system to fight cancer. Many target molecules on the surface of immune cells to help boost their ability to recognise and attack cancer cells.
But they’re not always as effective as expected.
“There are still a large number of patients who don’t respond to immunotherapy treatments and for the most part we still don’t understand the reasons for that,” says Burr.
To begin unpicking those reasons, the team homed in on a molecule that plays a vital role in our immune response, called MHC class I. This molecule helps immune cells identify and destroy potential threats, including cancer cells.
But some cancer cells find a way to evade detection, by removing MHC class I molecules from their surface. This could render them resistant to immunotherapy, by making them practically invisible to the immune system.
The big question the team wanted to answer was, how? Working with Professor Paul Lehner, they used gene editing tools to see what causes MHC class I to disappear from the surface of tumour cells.
“We were looking to see if there were any genes that we could take out that would put MHC class I back on the surface of the cancer cell,” says Burr. “And that was how we found the PRC2 complex.”
Publishing their work in Cancer Cell, a team led by Burr and Professor Mark Dawson at the Peter MacCallum Cancer Centre found that a group of proteins, called PRC2, could stop MHC class I appearing on the surface of some tumour cells in the lab.
The next step was to stop the PRC2 complex from doing this.
“In a range of cancers, particularly small cell lung cancer (SCLC), Merkel cell carcinoma and Neuroblastoma, we were able to show that by interrupting this group of proteins, MHC class I was put back on the surface of the tumour,” said Burr.
And blocking PRC2 activity in mice made immune cells more able to find and destroy tumour cells.
This isn’t the first time the PRC2 complex has been targeted. “Inhibitors are already in clinical trials in a range of different cancers,” says Burr. “And they have been fairly well tolerated.”
Burr thinks that the next step is to look at combining PRC2 inhibitors with different immunotherapies, to find the most effective treatment for cancers that have low levels of MHC class I.
Which led the team to think – could the devil facial tumour also be using the PRC2 complex to avoid the immune system?
The devil in the detail
“As it is contagious, the devil facial tumour provides an extreme model of tumour immune evasion,” says Burr. To avoid being destroyed as they spread between devils, the tumour cells have evolved sophisticated ways to hide from the immune system.
And it turns out one of those ways involves our old friend, the PRC2 complex.
The team saw the same thing happening in Tasmanian devil tumours cells as in human cells and mice. MHC class I was being suppressed by the activity of PRC2.
The fact that PRC2 helps cancer cells evade the immune system in multiple species could be an indicator of how much cancer cells rely on this pathway to avoid the immune system. And resist the effects of immunotherapy.
“What we think is really important about this function of PRC2 is the fact that we see it in devils, we see it in mice and we see it in humans, which means it is highly conserved and is likely to be an important mechanism of resistance for the tumour cells.”
Ethan
Reference
Burr et al. (2019). An Evolutionarily Conserved Function of Polycomb Silences the MHC Class I Antigen Presentation Pathway and Enables Immune Evasion in Cancer. Cancer Cell. DOI: 10.1016/j.ccell.2019.08.008
from Cancer Research UK – Science blog https://ift.tt/2lQHq2x
A peculiar type of tumour, in an even more peculiar type of animal, could hold some clues to help scientists overcome immunotherapy resistance in humans.
Not many of us will have come across a Tasmanian devil in the wild – they’re only found on the island state of Tasmania. These creatures, similar in size to a small dog, are susceptible to a particular form of cancer, called devil facial tumour. And what’s unique about these tumours is that, unlike human cancers, they can be passed from devil to devil.
Tasmanian devils transmit the tumours by biting each other on the mouth, which they often do as part of a mating ritual. The cancer is almost always lethal, and with DFT now covering most of Tasmania, the future of devils in the wild is uncertain. Teams at the University of Tasmania Menzies Institute for Medical Research and School of Medicine are working to understand devil facial tumour in an attempt to conserve the population.
Serendipitously, this work could help cancer scientists understand why some people don’t respond to immunotherapy.
But first, we need to come back to the UK.
Cancer resistance and immunotherapy
In Cambridge, Dr Marian Burr and her colleagues were trying to understand why some immunotherapies were not getting the responses they were anticipating.
Immunotherapy treatments can work in lots of different ways, but they all aim to harness our immune system to fight cancer. Many target molecules on the surface of immune cells to help boost their ability to recognise and attack cancer cells.
But they’re not always as effective as expected.
“There are still a large number of patients who don’t respond to immunotherapy treatments and for the most part we still don’t understand the reasons for that,” says Burr.
To begin unpicking those reasons, the team homed in on a molecule that plays a vital role in our immune response, called MHC class I. This molecule helps immune cells identify and destroy potential threats, including cancer cells.
But some cancer cells find a way to evade detection, by removing MHC class I molecules from their surface. This could render them resistant to immunotherapy, by making them practically invisible to the immune system.
The big question the team wanted to answer was, how? Working with Professor Paul Lehner, they used gene editing tools to see what causes MHC class I to disappear from the surface of tumour cells.
“We were looking to see if there were any genes that we could take out that would put MHC class I back on the surface of the cancer cell,” says Burr. “And that was how we found the PRC2 complex.”
Publishing their work in Cancer Cell, a team led by Burr and Professor Mark Dawson at the Peter MacCallum Cancer Centre found that a group of proteins, called PRC2, could stop MHC class I appearing on the surface of some tumour cells in the lab.
The next step was to stop the PRC2 complex from doing this.
“In a range of cancers, particularly small cell lung cancer (SCLC), Merkel cell carcinoma and Neuroblastoma, we were able to show that by interrupting this group of proteins, MHC class I was put back on the surface of the tumour,” said Burr.
And blocking PRC2 activity in mice made immune cells more able to find and destroy tumour cells.
This isn’t the first time the PRC2 complex has been targeted. “Inhibitors are already in clinical trials in a range of different cancers,” says Burr. “And they have been fairly well tolerated.”
Burr thinks that the next step is to look at combining PRC2 inhibitors with different immunotherapies, to find the most effective treatment for cancers that have low levels of MHC class I.
Which led the team to think – could the devil facial tumour also be using the PRC2 complex to avoid the immune system?
The devil in the detail
“As it is contagious, the devil facial tumour provides an extreme model of tumour immune evasion,” says Burr. To avoid being destroyed as they spread between devils, the tumour cells have evolved sophisticated ways to hide from the immune system.
And it turns out one of those ways involves our old friend, the PRC2 complex.
The team saw the same thing happening in Tasmanian devil tumours cells as in human cells and mice. MHC class I was being suppressed by the activity of PRC2.
The fact that PRC2 helps cancer cells evade the immune system in multiple species could be an indicator of how much cancer cells rely on this pathway to avoid the immune system. And resist the effects of immunotherapy.
“What we think is really important about this function of PRC2 is the fact that we see it in devils, we see it in mice and we see it in humans, which means it is highly conserved and is likely to be an important mechanism of resistance for the tumour cells.”
Ethan
Reference
Burr et al. (2019). An Evolutionarily Conserved Function of Polycomb Silences the MHC Class I Antigen Presentation Pathway and Enables Immune Evasion in Cancer. Cancer Cell. DOI: 10.1016/j.ccell.2019.08.008
from Cancer Research UK – Science blog https://ift.tt/2lQHq2x
A peculiar type of tumour, in an even more peculiar type of animal, could hold some clues to help scientists overcome immunotherapy resistance in humans.
Not many of us will have come across a Tasmanian devil in the wild – they’re only found on the island state of Tasmania. These creatures, similar in size to a small dog, are susceptible to a particular form of cancer, called devil facial tumour. And what’s unique about these tumours is that, unlike human cancers, they can be passed from devil to devil.
Tasmanian devils transmit the tumours by biting each other on the mouth, which they often do as part of a mating ritual. The cancer is almost always lethal, and with DFT now covering most of Tasmania, the future of devils in the wild is uncertain. Teams at the University of Tasmania Menzies Institute for Medical Research and School of Medicine are working to understand devil facial tumour in an attempt to conserve the population.
Serendipitously, this work could help cancer scientists understand why some people don’t respond to immunotherapy.
But first, we need to come back to the UK.
Cancer resistance and immunotherapy
In Cambridge, Dr Marian Burr and her colleagues were trying to understand why some immunotherapies were not getting the responses they were anticipating.
Immunotherapy treatments can work in lots of different ways, but they all aim to harness our immune system to fight cancer. Many target molecules on the surface of immune cells to help boost their ability to recognise and attack cancer cells.
But they’re not always as effective as expected.
“There are still a large number of patients who don’t respond to immunotherapy treatments and for the most part we still don’t understand the reasons for that,” says Burr.
To begin unpicking those reasons, the team homed in on a molecule that plays a vital role in our immune response, called MHC class I. This molecule helps immune cells identify and destroy potential threats, including cancer cells.
But some cancer cells find a way to evade detection, by removing MHC class I molecules from their surface. This could render them resistant to immunotherapy, by making them practically invisible to the immune system.
The big question the team wanted to answer was, how? Working with Professor Paul Lehner, they used gene editing tools to see what causes MHC class I to disappear from the surface of tumour cells.
“We were looking to see if there were any genes that we could take out that would put MHC class I back on the surface of the cancer cell,” says Burr. “And that was how we found the PRC2 complex.”
Publishing their work in Cancer Cell, a team led by Burr and Professor Mark Dawson at the Peter MacCallum Cancer Centre found that a group of proteins, called PRC2, could stop MHC class I appearing on the surface of some tumour cells in the lab.
The next step was to stop the PRC2 complex from doing this.
“In a range of cancers, particularly small cell lung cancer (SCLC), Merkel cell carcinoma and neuroblastoma, we were able to show that by interrupting this group of proteins, MHC class I was put back on the surface of the tumour,” said Burr.
And blocking PRC2 activity in mice made immune cells more able to find and destroy tumour cells.
This isn’t the first time the PRC2 complex has been targeted. “Inhibitors are already in clinical trials in a range of different cancers,” says Burr. “And they have been fairly well tolerated.”
Burr thinks that the next step is to look at combining PRC2 inhibitors with different immunotherapies, to find the most effective treatment for cancers that have low levels of MHC class I.
Which led the team to think – could the devil facial tumour also be using the PRC2 complex to avoid the immune system?
The devil in the detail
“As it is contagious, the devil facial tumour provides an extreme model of tumour immune evasion,” says Burr. To avoid being destroyed as they spread between devils, the tumour cells have evolved sophisticated ways to hide from the immune system.
And it turns out one of those ways involves our old friend, the PRC2 complex.
The team saw the same thing happening in Tasmanian devil tumours cells as in human cells and mice. MHC class I was being suppressed by the activity of PRC2.
The fact that PRC2 helps cancer cells evade the immune system in multiple species could be an indicator of how much cancer cells rely on this pathway to avoid the immune system. And resist the effects of immunotherapy.
“What we think is really important about this function of PRC2 is the fact that we see it in devils, we see it in mice and we see it in humans, which means it is highly conserved and is likely to be an important mechanism of resistance for the tumour cells.”
Ethan
from Cancer Research UK – Science blog https://ift.tt/2lnlrjd
A peculiar type of tumour, in an even more peculiar type of animal, could hold some clues to help scientists overcome immunotherapy resistance in humans.
Not many of us will have come across a Tasmanian devil in the wild – they’re only found on the island state of Tasmania. These creatures, similar in size to a small dog, are susceptible to a particular form of cancer, called devil facial tumour. And what’s unique about these tumours is that, unlike human cancers, they can be passed from devil to devil.
Tasmanian devils transmit the tumours by biting each other on the mouth, which they often do as part of a mating ritual. The cancer is almost always lethal, and with DFT now covering most of Tasmania, the future of devils in the wild is uncertain. Teams at the University of Tasmania Menzies Institute for Medical Research and School of Medicine are working to understand devil facial tumour in an attempt to conserve the population.
Serendipitously, this work could help cancer scientists understand why some people don’t respond to immunotherapy.
But first, we need to come back to the UK.
Cancer resistance and immunotherapy
In Cambridge, Dr Marian Burr and her colleagues were trying to understand why some immunotherapies were not getting the responses they were anticipating.
Immunotherapy treatments can work in lots of different ways, but they all aim to harness our immune system to fight cancer. Many target molecules on the surface of immune cells to help boost their ability to recognise and attack cancer cells.
But they’re not always as effective as expected.
“There are still a large number of patients who don’t respond to immunotherapy treatments and for the most part we still don’t understand the reasons for that,” says Burr.
To begin unpicking those reasons, the team homed in on a molecule that plays a vital role in our immune response, called MHC class I. This molecule helps immune cells identify and destroy potential threats, including cancer cells.
But some cancer cells find a way to evade detection, by removing MHC class I molecules from their surface. This could render them resistant to immunotherapy, by making them practically invisible to the immune system.
The big question the team wanted to answer was, how? Working with Professor Paul Lehner, they used gene editing tools to see what causes MHC class I to disappear from the surface of tumour cells.
“We were looking to see if there were any genes that we could take out that would put MHC class I back on the surface of the cancer cell,” says Burr. “And that was how we found the PRC2 complex.”
Publishing their work in Cancer Cell, a team led by Burr and Professor Mark Dawson at the Peter MacCallum Cancer Centre found that a group of proteins, called PRC2, could stop MHC class I appearing on the surface of some tumour cells in the lab.
The next step was to stop the PRC2 complex from doing this.
“In a range of cancers, particularly small cell lung cancer (SCLC), Merkel cell carcinoma and neuroblastoma, we were able to show that by interrupting this group of proteins, MHC class I was put back on the surface of the tumour,” said Burr.
And blocking PRC2 activity in mice made immune cells more able to find and destroy tumour cells.
This isn’t the first time the PRC2 complex has been targeted. “Inhibitors are already in clinical trials in a range of different cancers,” says Burr. “And they have been fairly well tolerated.”
Burr thinks that the next step is to look at combining PRC2 inhibitors with different immunotherapies, to find the most effective treatment for cancers that have low levels of MHC class I.
Which led the team to think – could the devil facial tumour also be using the PRC2 complex to avoid the immune system?
The devil in the detail
“As it is contagious, the devil facial tumour provides an extreme model of tumour immune evasion,” says Burr. To avoid being destroyed as they spread between devils, the tumour cells have evolved sophisticated ways to hide from the immune system.
And it turns out one of those ways involves our old friend, the PRC2 complex.
The team saw the same thing happening in Tasmanian devil tumours cells as in human cells and mice. MHC class I was being suppressed by the activity of PRC2.
The fact that PRC2 helps cancer cells evade the immune system in multiple species could be an indicator of how much cancer cells rely on this pathway to avoid the immune system. And resist the effects of immunotherapy.
“What we think is really important about this function of PRC2 is the fact that we see it in devils, we see it in mice and we see it in humans, which means it is highly conserved and is likely to be an important mechanism of resistance for the tumour cells.”
Ethan
from Cancer Research UK – Science blog https://ift.tt/2lnlrjd
The International Astronomical Union (IAU) said this week (September 24) that the orbit of the second suspected interstellar visitor – originally designated C/2019 Q4 – is now sufficiently well known they are are confident the object is:
… unambiguously interstellar in origin.
And thus they’ve now given this object – which is believed to be a comet – a new name. Its name is 2I/Borisov. The “I” stands for interstellar. The “2” means it’s the second such object known to astronomers. And, following a long-standing naming convention for comets, Borisov is the name of its discoverer.
The IAU said in a statement:
On August 30, 2019, the amateur astronomer Gennady Borisov, from MARGO observatory, Crimea, discovered an object with a comet-like appearance. The object has a condensed coma, and more recently a short tail has been observed. Mr. Borisov made this discovery with a 0.65-meter telescope he built himself.
After a week of observations by amateur and professional astronomers all over the world, the IAU Minor Planet Center was able to compute a preliminary orbit, which suggested this object was interstellar — only the second such object known to have passed through the solar system …
2I/Borisov will make its closest approach to the sun (reach its perihelion) on December 7, 2019, when it will be 2 astronomical units [AU, or Earth-sun distances] from the sun and also 2 AU from Earth. By December and January, it is expected that [the object] will be at its brightest in the southern sky. It will then begin its outbound journey, eventually [probably] leaving the solar system forever …
Estimates of the sizes of comets are difficult because the small cometary nucleus is embedded in the coma, but, from the observed brightness, 2I/Borisov appears to be around a few kilometers in diameter. One of the largest telescopes in the world, the 10.4-meter Gran Telescopio Canarias in the Canary Islands, has already obtained a spectrum of 2I/Borisov and has found it to resemble those of typical cometary nuclei.
Why are astronomers convinced this object is interstellar? The reason is its orbit, which they’ve now tracked long enough and well enough to know that – after it rounds the sun in December – 2I/Borisov will head outward again and (most likely) won’t be returning to our solar system.
Astronomers describe orbits like that of 2I/Borisov as hyperbolic. Astronomers have been discovering weakly hyperbolic comets that were perturbed out of the Oort Cloud since the mid-1800s. They’ve discovered thousands of hyperbolic comets so far. But, of all of these comets, the IAU said:
…none has an orbit as hyperbolic as that of 2I/Borisov. This conclusion is independently supported by the NASA JPL Solar System Dynamics Group. Coming just two years after the discovery of the first interstellar object 1I/‘Oumuamua, this new finding suggests that such objects may be sufficiently numerous to provide a new way of investigating processes in planetary systems beyond our own.
The IAU also said that astronomers are eagerly observing this object, which will be continuously observable for many months, a period longer than that of its predecessor, 1I/‘Oumuamua. They said:
Astronomers are optimistic about their chances of studying this rare guest in great detail.
Bottom line: The first known interstellar visitor received the official name ‘Oumuamua, meaning ‘scout.’ This one has a less romantic name and one that sets a standard for future discoveries: 2I/Borisov.
The International Astronomical Union (IAU) said this week (September 24) that the orbit of the second suspected interstellar visitor – originally designated C/2019 Q4 – is now sufficiently well known they are are confident the object is:
… unambiguously interstellar in origin.
And thus they’ve now given this object – which is believed to be a comet – a new name. Its name is 2I/Borisov. The “I” stands for interstellar. The “2” means it’s the second such object known to astronomers. And, following a long-standing naming convention for comets, Borisov is the name of its discoverer.
The IAU said in a statement:
On August 30, 2019, the amateur astronomer Gennady Borisov, from MARGO observatory, Crimea, discovered an object with a comet-like appearance. The object has a condensed coma, and more recently a short tail has been observed. Mr. Borisov made this discovery with a 0.65-meter telescope he built himself.
After a week of observations by amateur and professional astronomers all over the world, the IAU Minor Planet Center was able to compute a preliminary orbit, which suggested this object was interstellar — only the second such object known to have passed through the solar system …
2I/Borisov will make its closest approach to the sun (reach its perihelion) on December 7, 2019, when it will be 2 astronomical units [AU, or Earth-sun distances] from the sun and also 2 AU from Earth. By December and January, it is expected that [the object] will be at its brightest in the southern sky. It will then begin its outbound journey, eventually [probably] leaving the solar system forever …
Estimates of the sizes of comets are difficult because the small cometary nucleus is embedded in the coma, but, from the observed brightness, 2I/Borisov appears to be around a few kilometers in diameter. One of the largest telescopes in the world, the 10.4-meter Gran Telescopio Canarias in the Canary Islands, has already obtained a spectrum of 2I/Borisov and has found it to resemble those of typical cometary nuclei.
Why are astronomers convinced this object is interstellar? The reason is its orbit, which they’ve now tracked long enough and well enough to know that – after it rounds the sun in December – 2I/Borisov will head outward again and (most likely) won’t be returning to our solar system.
Astronomers describe orbits like that of 2I/Borisov as hyperbolic. Astronomers have been discovering weakly hyperbolic comets that were perturbed out of the Oort Cloud since the mid-1800s. They’ve discovered thousands of hyperbolic comets so far. But, of all of these comets, the IAU said:
…none has an orbit as hyperbolic as that of 2I/Borisov. This conclusion is independently supported by the NASA JPL Solar System Dynamics Group. Coming just two years after the discovery of the first interstellar object 1I/‘Oumuamua, this new finding suggests that such objects may be sufficiently numerous to provide a new way of investigating processes in planetary systems beyond our own.
The IAU also said that astronomers are eagerly observing this object, which will be continuously observable for many months, a period longer than that of its predecessor, 1I/‘Oumuamua. They said:
Astronomers are optimistic about their chances of studying this rare guest in great detail.
Bottom line: The first known interstellar visitor received the official name ‘Oumuamua, meaning ‘scout.’ This one has a less romantic name and one that sets a standard for future discoveries: 2I/Borisov.
