The search for a magic bullet to kill only cancer cells has been on for years.
© Getty Images
New candidate cancer drug does damage only in tumours.
A new drug turns lethal only when it reaches cancer cells. In healthy cells it is harmless. Though not yet shown to work in humans, it is a step towards a magic bullet to knock out tumour cells selectively, with minimal side effects.
The drug works in mice implanted with human tumours, say chemists Lutz Tietze and colleagues at the University of Gottingen in Germany. Before being treated with the drug, the mice are given an enzyme to activate it that sticks only to the human tumour cells, ignoring healthy mouse cells. So the drug is safe until the enzyme activates it in the tumour. Then it destroys the cancerous cells1.
Most existing chemotherapy is toxic to normal cells as well as cancerous ones. This causes severe side effects, such as a depressed immune system. Cancer researchers long for a magic bullet: a drug that works only where it is needed.
The warhead of the Gottingen antitumour molecule is a ring of three carbon atoms. This ring is highly strained and apt to burst open. Open, it is a reactive molecule that wreaks havoc among the nucleic acid molecules essential for normal cell function. The chemists copied this trick from a highly toxic antibiotic produced by a fungus.
So that their molecular bomb does not detonate everywhere in the body, the team have made a ’prodrug’. This is like the natural antibiotic but without the strained ring and with a sugar safety-catch. Once the sugar is clipped off, the molecule rearranges itself into a three-atom ring, and proceeds to do its toxic business.
Tietze’s team uses an enzyme to cut away the sugar safety-catch. An antibody on the enzyme acts as a tumour-specific hook. Such antibodies linked to toxic or radioactive molecules have long been explored for making magic-bullet drugs; none has yet found clinical use.
The advantage of this enzyme-activated approach, originally developed in the 1980s, is that the drug isn’t even activated until it reaches the target site. The selectivity of the damage still depends on antibody’s ability to hook onto the right cells, and on the absence of other enzymes in the body that also activate the prodrug.
Whether the idea will work cleanly enough in humans remains to be seen.
PHILIP BALL | © Nature News Service
Tracking movement of immune cells identifies key first steps in inflammatory arthritis
23.01.2017 | Massachusetts General Hospital
Team discovers how bacteria exploit a chink in the body's armor
20.01.2017 | University of Illinois at Urbana-Champaign
For the first time ever, a cloud of ultra-cold atoms has been successfully created in space on board of a sounding rocket. The MAIUS mission demonstrates that quantum optical sensors can be operated even in harsh environments like space – a prerequi-site for finding answers to the most challenging questions of fundamental physics and an important innovation driver for everyday applications.
According to Albert Einstein's Equivalence Principle, all bodies are accelerated at the same rate by the Earth's gravity, regardless of their properties. This...
An important step towards a completely new experimental access to quantum physics has been made at University of Konstanz. The team of scientists headed by...
Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...
Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.
While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...
Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales
Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...
19.01.2017 | Event News
10.01.2017 | Event News
09.01.2017 | Event News
23.01.2017 | Health and Medicine
23.01.2017 | Physics and Astronomy
23.01.2017 | Process Engineering