New Cancer Treatment “Remembers” Tumors and Won’t Let Them Regrow

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Researchers have found a way to train the immune system to eradicate cancer cells and “remember” them in case they try to return. A report of the technique was published today in the journal Science Immunology.

Cancer is a stealthy invader. Rather than facing the body’s defenses head-on, it manipulates the sentries of our immune system, shutting them down or even turning them against us.

One commonly hijacked sentry is called the CD4+ T regulatory (Treg) cell. When they’ve been bamboozled by cancer, Treg cells tell our defenses to leave tumors alone. So if we could find a way to shut those Treg cells up, our immune systems would, theoretically, treat cancer like the intruder it is. The problem is that Treg cells are themselves kind of slippery and hard to target with drugs.

One possible way in is a molecule called LAP, which has previously been linked to worse outcomes for people with cancer.

To learn more, researchers examined interactions between Treg cells and LAP in mice with melanoma, colon cancer, and brain cancer. They found that zapping the molecule with special anti-LAP antibodies did the trick, effectively shutting the hijacked cells down so the immune system could do its work. Mice treated with these antibodies had lower levels of Treg cells and cancer cells.

Better yet, when the researchers mixed the anti-LAP antibodies with tumor vaccines, they discovered that tumors wouldn’t grow, even in mice exposed to cancer-causing proteins. The effects of this cocktail lasted for months.

Best of all, the treatment seemed to create “memories” of the tumors in the rodents’ immune systems, enabling them to recognize cancer cells more quickly and prevent relapse.

Before you get too excited, we should mention a few things about these experiments. First, as we’ve said before and will say again, mice are not people. Second, the treatments were tested under the mice’s skin, not in the places where these tumors would naturally grow.

Still, the researchers say, the anti-LAP molecules are a good step, and they are eager to explore them further.

What Caused Pangea to Break Apart?

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iStock.com/alfimimnill

Emily Devenport:

There's another way to look at this question. People tend to think in terms of supercontinents forming and then breaking up again due to convection currents in the mantle, hot material rising and causing rifts in weaker spots, possibly in old sutures where the continents were shoved together—but what is really happening is that ocean basins are opening and closing, and the ocean has an active role in subduction.

The opening and closing of an ocean basin is called a Wilson Cycle. It begins when hot material rising from the mantle stretches the overlying crust. As molten material rises, a rift is formed. The rift is widened as material continues to squeeze into it. If that rifting goes on long enough, through a broad enough swath of a continent, ocean water will eventually flow into it, and an ocean basin begins to form. The upwelling of hot material will continue to rise through that thinner area of crust, pushing the plates apart. The Atlantic Ocean is an example of a basin that is well along in the Wilson Cycle; eventually subduction is going to begin at its margins, and the whole shebang will pivot.

This will happen because at the edge of continents, sediments accumulate. The weight of those sediments, combined with the weight of the water, drives the heavier, denser edge of the oceanic plate under the continental crust, which is fatter and lighter. Eventually subduction begins, and the basin begins to close again. The Pacific Ocean is an example of a basin that's closing.

If you look at a map of the oceanic rift zones, you'll notice that the one in the Atlantic is pretty much in the middle of that ocean, but the Pacific rift zone has been pulled all the way over to North America above Central America. Subduction is actively occurring on all margins of that plate.

The simple picture is that the continents are moving toward each other across the Pacific Ocean while the Atlantic Basin continues to widen. The truth is more complicated. When plates subduct, the water in the crust lowers the melting point of those rocks, so partial melting occurs. The partially melted material begins to rise through the overlying rocks, because it's less dense, and decompression melting occurs. Eventually, the upwelling of hot material forms plutons and volcanoes above the subduction zones. Fore-arc and Back-arc [PDF] basins can form. As the oceanic crust is pulled under the continental plate, island chains and other chunky bits get sutured to the edge of the continent along with sediments, making it larger. Our world is ~4.6 billion years old, so our continents are really large, now. They're unlikely to rift through the ancient cratons that formed their hearts.

What will happen if subduction begins on the eastern side of North America before the Pacific Basin closes? The margin next to California is a transform fault; it's not subducting. Will it eventually push itself under that part of North America again, or will the transform zone get bigger? The hot spot that was driving the ancient Farallon Plate under North America was eventually overridden by the southwestern states (Arizona, New Mexico, etc.) forming a rift zone. Will it continue to rift or poop out?

There are computer models predicting what supercontinent may form next. They will continue to change as our understanding of tectonic processes gets more accurate.

This post originally appeared on Quora. Click here to view.

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