Sperm may be uniquely equipped to deliver chemo to cervical cancer cells

Researchers are studying the use of sperm cells as micromotors for delivering chemotherapy to cervical cancer patients.

Sperm on the prowl
Sperm on the hunt (TATIANA SHEPELEVA via SHUTTERSTOCK)

One of the obvious problems with conventional chemotherapy is that it’s essentially poison formulated to kill cancer cells without killing the patient. While chemo is often the only available treatment option, it’s extremely rough on patients, causing debilitating exhaustion, weakness, and nausea. As a result, it can only be administered in limited doses. In addition, chemo can be diluted by body fluids and be broken down and weakened by enzymes. Now a team of scientists at Leibnitz Institute for Solid State and Materials Research are exploring a new way to aim cancer medications with greater precision directly at tumors while reducing side effects, thus making it safe to administer higher, more effective doses. That new way? Sperm cells.


The team, led by Haifeng Xu, is interested in the use of sperm as a delivery mechanism in the female reproductive system, starting with cancer, and in time perhaps addressing other conditions such as ectopic pregnancies and endometriosis. Their research has just been published in ACSNANO. It explains why they’re interested in sperm cells as a potential delivery mechanism: “…sperms are excellent candidates to operate in physiological environments, as they do neither express pathogenic proteins nor proliferate to form undesirable colonies, unlike other cells or microorganisms. Overall, this sperm-hybrid micromotor is a biocompatible platform that can be used in gynecological healthcare, treating or detecting cancer or other diseases in the female reproductive system in the future.” It also notes, that, of course, “sperms are naturally optimized to efficiently swim in the female reproductive system.” 

 

 

The team’s first experiment targeted mini-cervical cancer tumors in a dish. Sperm cells were infused with doxorubicin hydrochloride (DOX-HCl), a frequently used form of chemo. It collected in the cells’ heads, with an average of 15 picograms of DOX-HCl per cell. The researchers then released the sperms into the medium, and they swam toward the tumors, delivering the drug and killing an impressive 87% of their cells in just three days.

The effect of the sperm-delivered chemo on in vitro-grown tumor steroids over three days (ACSNANO)

The second round of tests involved something even more surprising. The team enclosed DOX-HCI sperm cells within minuscule tetrapods — four-armed magnetic harnesses — so the spermbots could be guided to tumors using magnets.

Scanning electron microscopy images of the harnesses (ACSNANO)

In experiments, when a spermbot bumped into a tumor, the impact bent the four arms, causing them to open and loosen their grip on the cells that then carried the DOX-HCI-laced cells into the tumor.

Schematic illustrating the mechanical release mechanism (ACSNANO)

With the sperm providing propulsion and the magnetic tetrapods their guidance system, the researchers see “sperm-hybrid micromotors” as offering intriguing advantages for chemo delivery over synthetic micromotors being developed by others. To start with, sperm’s ability to fuse with somatic cells protects medications from dilution and breakdown. Also, they can “swim through complex environments” due to their beating tails and membrane biochemistry that make the female reproductive system a comfortable environment. In addition, can last longer in the body since they’re less likely to be in conflict with the patient’s immune system due to proteins and prostasomes on sperm cells’ membranes.

(NEW SCIENTIST)

 


 

A landslide is imminent and so is its tsunami

An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.

Image source: Christian Zimmerman/USGS/Big Think
Surprising Science
  • A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
  • A wall of rock exposed by a receding glacier is about crash into the waters below.
  • Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.

The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.

Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .

"It could happen anytime, but the risk just goes way up as this glacier recedes," says hydrologist Anna Liljedahl of Woods Hole, one of the signatories to the letter.

The Barry Arm Fjord

Camping on the fjord's Black Sand Beach

Image source: Matt Zimmerman

The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.

Not Alaska’s first watery rodeo, but likely the biggest

Image source: whrc.org

There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.

The Barry Arm event will be larger than either of these by far.

"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."

Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.

What the letter predicts for Barry Arm Fjord

Moving slowly at first...

Image source: whrc.org

"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."

The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.

Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.

Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.

While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.

Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."

How do you prepare for something like this?

Image source: whrc.org

The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:

"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."

In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.

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