A new method of theranostics
We are talking about a new intelligent therapeutic agent for accurate diagnosis and therapy of tumors, which circulates in the blood in the form of small molecules and, once in the tumor, self-organizes into larger nanostructures and is activated by the tumor microenvironment for therapy using photoacoustic (FA) imaging.
Despite the fact that various technologies have been developed for FA imaging, a relatively small number of tools demonstrate high selectivity in the tumor microenvironment for imaging and on-demand therapy. In this study, scientists from the University of Wisconsin-Madison (USA) have assembled an intelligent therapeutic agent from molybdenum-based polyoxometallate clusters (Ox-POM). These clusters work in the body like a smart nanorobot: they first examine the tumor area, providing images with FA-visualization, and then kill cancer cells (photothermal therapy).
Unlike traditional chemotherapy, intelligent Ox-POM clusters, synthesized easily and quickly, act directly in the tumor without damaging normal tissues and organs.
A new system of redox photothermal therapy (FTT) based on FA imaging was tested in experiments on mouse models. Ox-POM clusters accumulated in the tumor and, under the influence of the microenvironment, turned into large nanoparticles absorbing near-infrared radiation. In vitro and in vivo experiments have demonstrated their therapeutic efficacy.
The results of positron emission tomography (PET) with labeled zirconium-89 Ox-POM showed that these clusters are mainly released through the kidneys, bypassing the liver and spleen. This is extremely important to reduce the potential toxic effects.
When injected into the body of mice, the FA signal was detected in the tumor within an hour after injection. When exposed to near-infrared radiation, the temperature in the tumor grew rapidly, reaching more than 40 °C after 30 seconds and 52°C after five minutes. The tumor growth was completely stopped without relapse during the next 2 months.
The obtained results demonstrate a new strategy for accurate diagnosis and treatment of tumors "on demand", which involves the creation of a new class of therapeutic agents based on clusters. Intelligent nanomaterials can also reduce the damage of normal organs and tissues by antitumor drugs and increase their effectiveness.
The study was presented at the Annual Conference of the Society of Nuclear Medicine and Molecular Imaging (SNMMI).
Article D. NI et al. Redox-Activated Photoacoustic Imaging-Guided Photothermal Therapy with Bioresponsive Polyoxometalate Cluster is published in the Journal of Nuclear Medicine.
Aminat Adzhieva, portal "Eternal Youth" http://vechnayamolodost.ru based on the materials of SNMMI: New Theranostic Strategy Developed for Precise Tumor Diagnosis and Therapy.