Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Cells bulge to squeeze through barriers

28.11.2017

New tool in cell's invasion machinery may help explain cancer's ability to spread

Invasive cells deploy a trick to break through tissues and spread to other parts of the body, researchers report.


This time-lapse video of an invading cell in the lab worm C. elegans shows a fleeting protrusion that may help explain how cancer spreads.

Video by Kaleb Naegeli, Duke University

In a new study, 3-D time-lapse imaging of cellular "break-ins" in the transparent worm C. elegans reveals a fleeting, yet key structure in action. A single protrusion bulges out from the cell surface, wedges a hole through the protective layer that separates the cell from other tissues, and swells until the breach is wide enough for the entire cell to squeeze through.

These findings could point to new ways to prevent metastasis, the spread of cancer cells which typically makes the disease more deadly and difficult to treat. The work appeared Nov. 20 in the journal Developmental Cell.

Most cells in the body stay put. But from time to time, cells trespass into other tissues, said lead author David Sherwood, a biology professor at Duke University.

The ability of cells to break and enter is critical for many normal processes, such as when the placenta attaches to the uterus during early pregnancy, or when immune cells push their way through blood vessel walls to get to sites of injury or infection.

Cell invasion is hijacked during metastasis, when cancer cells leave their original tumor sites and spread to other parts of the body.

To spread, a cell must first penetrate a sheet-like mesh of proteins and other molecules called the basement membrane, which supports and surrounds tissues like a Kevlar wrapper.

One of the first steps in this breakthrough process was recognized 30 years ago, Sherwood said. The basement membrane is too dense to slip through, so invading cells begin by pushing out tiny "feet" many times finer than a human hair, called invadopodia. These piston-like projections pop out of the cell surface every few seconds and then retract, until one punches a tiny hole in the basement membrane. What happens after the initial breach, however, was less clear.

In the new study, researchers identify a second structure that takes over after invadopodia make the first puncture.

Sherwood's group used a camera attached to a powerful microscope to take pictures of invading worm cells every five minutes for up to three hours.

They tracked a specialized cell called the anchor cell, which breaks through the basement membrane that separates the worm's uterus from its vulva to connect them so the worm can lay eggs.

Sherwood and colleagues discovered that the C. elegans anchor cell accomplishes this task with the help of a single large protrusion that wedges into the tiny hole created by the invadopodia, like a foot in the door. As the protrusion enlarges, it shoves the basement membrane aside and expands the existing hole.

Rather than stretching like a balloon, the researchers found, the protrusion inflates by adding to the cell membrane from within. Tiny sacs inside the cell called lysosomes concentrate at the breach site. Once there, they fuse with the cell's outer membrane, increasing its surface area. As the protrusion swells, a protein called dystroglycan clusters at its base to keep the bulge from deflating.

The pushing forces "clear a path for invasion similar to the way a balloon catheter inflates to open an artery," Sherwood said. Within a half hour it contracts, leaving behind a hole wide enough for the cell to move through.

To make the protrusion, the study shows, the cell relies on a chemical cue called netrin and its receptor to direct lysosomes to the site. High netrin levels have been linked to metastasis in numerous human cancers, which suggests the mechanism the researchers found is a common feature of invasive cells, Sherwood said.

The findings might also explain why drugs designed to block the spread of cancer by targeting invading cells have failed.

Several proposed treatments work by inhibiting enzymes called metalloproteinases that dissolve the basement membrane. The reason such therapies have had limited success in clinical trials, Sherwood said, may be because they ignore a pivotal player in cancer progression -- these inflatable protrusions that bulge out from the tumor cell and push the basement membrane aside.

Figuring out how to block the netrin pathway and prevent cancer cells from putting out new protrusions might deprive them of a critical tool they use to spread, Sherwood said.

"Migrating cells have a remarkable repertoire of invasion tactics," Sherwood said. "This study reveals another trick up their sleeve."

###

This research was supported by the American Cancer Society (129351-PF-16-024-01-CSM), the National Institutes of Health (GM121015-01, F32 GM115151) and the National Institute of General Medical Sciences (R01 GM083071, R01 GM079320, R35 MIRA GM118049).

CITATION: "Cell Invasion in Vivo Via Rapid Exocytosis of a Transient Lysosome-Derived Membrane Domain," Kaleb Naegeli, Eric Hastie, Aastha Garde, Zheng Wang, Daniel Keeley, Kacy Gordon, Ariel Pani, Laura Kelley, Meghan Morrisey, Qiuyi Chi, Bob Goldstein and David Sherwood. Developmental Cell, Nov. 20, 2017. https://doi.org/10.1016/j.devcel.2017.10.024.

Media Contact

Robin Ann Smith
ras10@duke.edu
919-681-8057

 @DukeU

http://www.duke.edu 

Robin Ann Smith | EurekAlert!

More articles from Life Sciences:

nachricht Turning carbon dioxide into liquid fuel
06.08.2020 | DOE/Argonne National Laboratory

nachricht Tellurium makes the difference
06.08.2020 | Friedrich-Schiller-Universität Jena

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: ScanCut project completed: laser cutting enables more intricate plug connector designs

Scientists at the Fraunhofer Institute for Laser Technology ILT have come up with a striking new addition to contact stamping technologies in the ERDF research project ScanCut. In collaboration with industry partners from North Rhine-Westphalia, the Aachen-based team of researchers developed a hybrid manufacturing process for the laser cutting of thin-walled metal strips. This new process makes it possible to fabricate even the tiniest details of contact parts in an eco-friendly, high-precision and efficient manner.

Plug connectors are tiny and, at first glance, unremarkable – yet modern vehicles would be unable to function without them. Several thousand plug connectors...

Im Focus: New Strategy Against Osteoporosis

An international research team has found a new approach that may be able to reduce bone loss in osteoporosis and maintain bone health.

Osteoporosis is the most common age-related bone disease which affects hundreds of millions of individuals worldwide. It is estimated that one in three women...

Im Focus: AI & single-cell genomics

New software predicts cell fate

Traditional single-cell sequencing methods help to reveal insights about cellular differences and functions - but they do this with static snapshots only...

Im Focus: TU Graz Researchers synthesize nanoparticles tailored for special applications

“Core-shell” clusters pave the way for new efficient nanomaterials that make catalysts, magnetic and laser sensors or measuring devices for detecting electromagnetic radiation more efficient.

Whether in innovative high-tech materials, more powerful computer chips, pharmaceuticals or in the field of renewable energies, nanoparticles – smallest...

Im Focus: Tailored light inspired by nature

An international research team with Prof. Cornelia Denz from the Institute of Applied Physics at the University of Münster develop for the first time light fields using caustics that do not change during propagation. With the new method, the physicists cleverly exploit light structures that can be seen in rainbows or when light is transmitted through drinking glasses.

Modern applications as high resolution microsopy or micro- or nanoscale material processing require customized laser beams that do not change during...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“Conference on Laser Polishing – LaP 2020”: The final touches for surfaces

23.07.2020 | Event News

Conference radar for cybersecurity

21.07.2020 | Event News

Contact Tracing Apps against COVID-19: German National Academy Leopoldina hosts international virtual panel discussion

07.07.2020 | Event News

 
Latest News

Rare Earth Elements in Norwegian Fjords?

06.08.2020 | Earth Sciences

Anode material for safe batteries with a long cycle life

06.08.2020 | Power and Electrical Engineering

Turning carbon dioxide into liquid fuel

06.08.2020 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>