Science Square

  • Issue 114 / November - December 2016



    Science Square

    The Fountain

    Neutralizing the Zika virus

    Sapparapu G et al. Neutralizing human antibodies prevent Zika virus replication and fetal disease in mice. Nature, November 2016.


    Scientists have identified a human antibody that can reduce Zika infection, giving rise to hopes that a vaccine may be developed. Zika is a mosquito-borne flavivirus, named after the Ugandan forest where it was first isolated from a monkey in 1947. Zika has become a global public health threat over the past decade because of its rapid spread, first to the Asia-Pacific region, and then to the Western hemisphere. Zika is found to cause microcephaly, unusually underdeveloped heads, and other congenital malformations in children born to infected women. In addition, Zika has been linked to Guillain-Barre syndrome, a neurological disorder that can lead to paralysis and death.  Scientists have discovered naturally occurring human antibodies, called ZIKV-117, which reduced the effects of infection in lab mice and their fetuses. The antibodies were found to react with the envelope or "E" protein on the surface of the virus. They then generated a variety of monoclonal antibodies against this envelope protein. This allowed researchers to rapidly generate a large amount of antibodies against specific viral targets. The next set of Zika studies will be performed on primates. If the potency and extent of inhibition holds up, ZIKV-117 could be developed as the first protective antibody treatment for pregnant women at risk of Zika infection.


    Dinosaur-Killing Asteroid Turned Earth’s Surface into Liquid

    Morgan JV et al. The formation of peak rings in large impact craters. Science, November 2016.


     


    A recent study of the massive Chicxulub crater in the Gulf of Mexico gives important insights into the formation of planets and life. The crater was formed when an asteroid struck the Earth, approximately 66 million years ago. The asteroid, which hit with the force of 100 million atomic bombs, opened a massive hole nearly 30 kilometers deep and 193 kilometers wide. The research team collected core samples of the peak ring, which is now covered by the Gulf of Mexico and the limestone of the modern gulf floor. The samples were enriched with pink granite, which is found deeper in the Earth, as opposed to the limestone that was present at the time of the impact. This reveals that the peak ring didn't come from shallow in the Earth’s crust, but from deeper in the mantle. Detailed mathematical modeling demonstrated that the 16-kilometer-wide Chicxulub asteroid pushed rocks up from 10 kilometers below the Earth’s surface. It did this by travelling approximately 32 kilometers in a few minutes, first pushing outward from the impact, then rebounding upward above the Earth's surface and finally collapsing outward to form a ring of peaks around the center of the impact. These findings support the theory that violent asteroid impacts cause a planet's surface to behave like a fluid. Scientists suggest that this fluid-like movement likely explains how the moon or other crater-dotted rocky planets such as Mercury and Venus were formed after large impacts. The devastation of Chicxulub asteroid caused a dramatic change in world history. The resulting fireballs and mega-tsunamis after the collision led to the sky darkening for many years, which consequently collapsed the food chain. This wiped out all non-avian dinosaurs along with the 50-75 percent of all other life on Earth. After this remarkable change, birds and mammals took over the planet; the disaster ultimately paved the way to the reign of humanity.


    Starving cancer cells to death

    Tang X et al. Cystine addiction of triple-negative breast cancer associated with EMT augmented death signaling. Oncogene, November 2016.


     


    Cancer restructures the metabolism of tumor cells, converting them into lean, dynamic, infinitely replicating cellular machines. But this also causes tumor cells to rely on very specific nutrients for survival. Researchers have been studying the nutritional addictions of tumor cells for many years, in the hopes of developing a new cancer treatment by cutting off these nutrients and ultimately starving tumors to death. A recent study was focused on a vicious and treatment-resistant form of breast cancer, called triple negative breast cancer. Patients with triple negative breast cancer, which constitute about 10-20 percent of all breast cancer cases, have few treatment options outside of surgery and chemotherapy. Searching for nutritional targets in these cells, scientist discovered that the triple negative breast cancer cells were very sensitive to being deprived of cysteine, a molecule made up from two copies of the amino acid cysteine linked together. When they removed cysteine from the cell culture media, the cancer cells died very rapidly.┬á Genetic analyses showed that cysteine “addiction” in tumor cells arises when immobile epithelial cells break away from the tissue and transform into circulating mesenchymal cells, which then spread throughout the body. Tumor cells use this transformation to metastasize around the body but scientists now want to exploit this pathway to cure the cancer by starving the tumor cells to death. They are currently in the process of testing the available cystine-blocking molecules on tumors and searching for biomarkers in other cancer types that may respond positively to this form of treatment.

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