Radioisotopes -- atoms displaying radioactivity -- can be used for both diagnosing and treating cancer. For diagnosis, radioisotopes that emit gamma rays are used because of their penetrating capability, while for treatment, isotopes emitting alpha particles, beta particles, or similar cytotoxic radiation are needed. (Cytotoxicity refers to the ability to kill or damage cells; in this case, cancer cells.)
In recent years, an approach combining therapy and diagnosis both based on radioisotopes, called 'radiotheranostics', has gained significance. The key idea is that both the diagnostic and the therapeutic isotope can be brought to a tumor by attaching it to the same carrier molecule.
The concept radiotheranostics using At-211 and I-123 for cancer diagnosis and therapy. Combination of SPECT imaging using I-123-labeled RGD peptide with targeted alpha therapy using At-211-labeled RGD peptide could be useful for personalized medicine to cancer.
Credit: Kanazawa University
Now, Kazuma Ogawa from Kanazawa University and colleagues have synthesized a radiotheranostic system with astatine (At-211) as the alpha-particle emitter and iodine (I-123) as the gamma-radiation source.
A few types of molecules can be used as radioisotope carriers. Ogawa and colleagues were able to use a peptide (a biomolecule consisting of a chain of amino acids) as the carrier for both the astatine and the iodine isotope.
Specifically, they worked with a peptide containing the so-called RGD sequence of amino acids. The RGD motif plays an important role in cell membrane binding; its cell-adhesive activity makes it a good component for designing molecules for targeting tumors.
The theranostic carrier molecules were synthesized through a series of chemical reactions, the last step being a halogenation -- the replacement of a particular molecular component by a halogen. (Both astatine and iodine are halogens, having similar chemical properties.)
After the successful synthesis of the At-211 and I-125 carrier molecules, the researchers tested their behavior in vivo. They simultaneously injected the two compounds in tumor-bearing mice, and looked at the biodistribution of the radioactive isotopes -- that is, in which parts of the body they occur, and how abundantly.
The main finding was that the At-211- and I-125-labeled RGD peptides displayed biodistributions that were very similar, with a high accumulation in the tumor -- a prerequisite for operating as a theranostic system. (Another iodine isotope, I-123, is foreseen to be the diagnostic radioisotope, but I-125 has a much longer half-life, making it easier to work with in the present experiments.)
The work of Ogawa and colleagues is an important step forward in the development of radiotheranostics. Quoting the scientists: "This method could be applicable to other peptides directly targeted to cancer. Moreover, future efforts should be focused on application of other radiohalogens ... as positron emitters for PET [positron-electron tomography] imaging ... "
Tomoya Sato | EurekAlert!
Study points to new drug target in fight against cancer
19.09.2019 | Rice University
Researchers develop tumour growth roadmap
19.09.2019 | Universität Leipzig
How long the battery of your phone or computer lasts depends on how many lithium ions can be stored in the battery's negative electrode material. If the battery runs out of these ions, it can't generate an electrical current to run a device and ultimately fails.
Materials with a higher lithium ion storage capacity are either too heavy or the wrong shape to replace graphite, the electrode material currently used in...
To process information, photons must interact. However, these tiny packets of light want nothing to do with each other, each passing by without altering the...
Researchers from the Department of Atomically Resolved Dynamics of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg, the University of Hamburg and the European Molecular Biology Laboratory (EMBL) outstation in the city have developed a new method to watch biomolecules at work. This method dramatically simplifies starting enzymatic reactions by mixing a cocktail of small amounts of liquids with protein crystals. Determination of the protein structures at different times after mixing can be assembled into a time-lapse sequence that shows the molecular foundations of biology.
The functions of biomolecules are determined by their motions and structural changes. Yet it is a formidable challenge to understand these dynamic motions.
At the International Symposium on Automotive Lighting 2019 (ISAL) in Darmstadt from September 23 to 25, 2019, the Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, a provider of research and development services in the field of organic electronics, will present OLED light strips of any length with additional functionalities for the first time at booth no. 37.
Almost everyone is familiar with light strips for interior design. LED strips are available by the metre in DIY stores around the corner and are just as often...
Later during this century, around 2060, a paradigm shift in global energy consumption is expected: we will spend more energy for cooling than for heating....
19.09.2019 | Event News
10.09.2019 | Event News
04.09.2019 | Event News
20.09.2019 | Life Sciences
20.09.2019 | Life Sciences
20.09.2019 | Life Sciences