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biophysics

Watching Cancer Cells Play Ball

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Credit: Ning Wang, University of Illinois at Urbana-Champaign

As tumor cells divide and grow, they push, pull, and squeeze one another. While scientists have suspected those mechanical stresses may play important roles in cancer, it’s been tough to figure out how. That’s in large part because there hadn’t been a good way to measure those forces within a tissue. Now, there is.

As described in Nature Communications, an NIH-funded research team has developed a technique for measuring those subtle mechanical forces in cancer and also during development [1]. Their ingenious approach is called the elastic round microgel (ERMG) method. It relies on round elastic microspheres—similar to miniature basketballs, only filled with fluorescent nanoparticles in place of air. In the time-lapse video above, you see growing and dividing melanoma cancer cells as they squeeze and spin one of those cell-sized “balls” over the course of 24 hours.


Snapshots of Life: Biological Bubble Machine

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plasma membrane vesicles

Credit: Chi Zhao, David Busch, Connor Vershel, Jeanne Stachowiak, University of Texas at Austin

As kids, most of us got a bang out of blowing soap bubbles and watching them float around. Biologists have learned that some of our cells do that too. On the right, you can see two cells (greenish yellow) in the process of forming bubbles, or plasma membrane vesicles (PMVs). During this blebbing process, a cell’s membrane temporarily disassociates from its underlying cytoskeleton, forming a tiny pouch that, over the course of about 30 minutes, is “inflated” with a mix of proteins and lipids from inside the cell. After the PMVs are fully filled, these bubble-like structures are pinched off and released, like those that you see in the background. Certain cells constantly release PMVs, along with other types of vesicles, and may use those to communicate with other cells throughout the body.

This particular image, an entrant in the Biophysical Society’s 2017 Art of Science Image Contest, was produced by researchers working in the NIH-supported lab of Jeanne Stachowiak at the University of Texas at Austin. Stachowiak’s group is among the first to explore the potential of PMVs as specialized drug-delivery systems to target cancer and other disorders [1].

Until recently, most efforts to exploit vesicles for therapeutic uses have employed synthetic versions of a different type of vesicle, called an exosome. But Stachowiak and others have realized that PMVs come with certain built-in advantages. A major one is that a patient’s own cells could in theory serve as the production facility.


Snapshots of Life: Imperfect but Beautiful Intruder

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RSV Particle

Credit: Boon Chong Goh, Beckman Institute, University of Illinois at Urbana-Champaign

The striking image you see above is an example of what can happen when scientists combine something old with something new. In this case, a researcher took the Rous sarcoma virus (RSV)—a virus that’s been studied for more than century because of its ability to cause cancer in chickens and the insights it provided on human oncogenes [1, 2]—and used modern computational tools to generate a model of its atomic structure.

Here you see an immature RSV particle that’s just budded from an infected chicken cell and entered the avian bloodstream. A lattice of proteins (red) held together by short peptides (green) cover the outer shell of the immature virus, shielding other proteins (blue) that make up an inner shell.