the medicinefire"(Tookad), for the treatment of solid malignant tumors developed by scientists of the Weizmann Institute of Science, is currently approved for the treatment of prostate cancer patients in early stages in Europe, Mexico and Israel and is under examination by the American Food and Drug Administration (FDA). Previous studies have shown that the drug treats cancer through the rapid inactivation of The blood supply to the tumor: it turns the vascular system of the tumor into a temporary "incubator of death" leading to the destruction of the tumor cells. So far there has been no reliable way to test how exactly the drug worksNew research Applied by scientists in the United States, in collaboration with the laboratory of Prof. Avigdor Shertz At the institute, an innovative imaging method aims to track in real time and with great precision the changes in the vascular system of the tumor - changes that lead to its eradication in a selective manner and without harming the adjacent tissues.
The origin of Toked, the result of the development of Prof. Shertz from the Department of Plant and Environmental Sciences, and the late Prof. Yoram Salomon from the Department of Biological Control - in chlorophyll found in marine bacteria that carry out photosynthesis. The drug, which is given by intravenous infusion and is quickly cleared from the bloodstream, takes effect in the body only after exposure to light, which is done through thin optical fibers inserted into the damaged tissue. Following exposure to light, the drug reacts with the oxygen molecules in the blood vessels and turns them into oxygen and nitrogen oxide radicals. The presence of the radicals triggers a chain of processes leading to the blockage of the blood vessels of the tumor and the destruction of its cells. However, until recently there was no effective way to monitor what exactly happens in the body after exposure to light, as the available technologies did not allow high enough resolution imaging.
Dr. Jan Grimm from the Cancer Center Memorial Sloan Kettering In New York - where Tokad is currently being tested in clinical trials - decided to investigate the mechanism of action of the drug using a new imaging method: scanning optoacoustic mesoscopy (RSOM). In this method, the tissue is exposed to laser flashes that cause light-absorbing molecules to expand - in this case, hemoglobin; Later, the supersonic waves (ultrasound) created due to this expansion are followed. The application of the method allowed the researchers to obtain a high-resolution image of the blood vessels in and around the tumor before, during and after the treatment in a cancer model in mice. The idea of harnessing the method for the study of time came to Dr. Grimm's mind after discussing the matter with Prof. Vassilis Nachakristos from the Technical University of Munich, who came for a sabbatical in his laboratory. Following this, he joined forces with Prof. Nachakristos and Prof. Schartz's laboratory .
"RSOM allowed us to obtain outstanding images, revealing the tissue response and the microscopic changes in blood vessels after treatment," wrote Dr. Grimm in a blog on the website of the scientific journal Nature. The images showed that shortly after the mice were treated with the drug, the blood vessels were blocked. The large ones feeding their tumors, and the small blood vessels inside the tumors began to be destroyed gradually Oxygen and nitrogen radicals that caused further destruction – as is usually the case when an area deprived of oxygen – eventually collapsed, and the cancerous tissue was destroyed. Tumors with many blood vessels were more affected by the drug than tumors with few blood vessels Another one may make it possible to enhance the effect of Tokud even in tumors with few blood vessels.
Revealing the mechanism of action of Toked at this unprecedented level of detail may optimize the treatment of the drug. For example, monitoring the vascular system of the tumor in patients may make it possible to predict how effective the treatment will be. This monitoring may also make it possible to adjust the treatment of patients in order to ensure that the tumor is successfully eradicated or alternatively to avoid over-treatment that could damage the nearby healthy tissues.
Dr. Katia Hedika, who was first trained in the laboratory of Prof. Schartz, Dr. Magdalena Scovel, Dr. Cheryl Roberts, Camila Longo-Machado, Karan Nagar, Xiao-Ting Hsu, Dr. Kwanga Kim, participated in the study. Dr. Thomas Reiner and Dr. Jonathan Coleman of Memorial Sloan Kettering Cancer Center; Dr. Lilach Agami from the Department of Plant and Environmental Sciences of the Weizmann Institute of Science; and Prof. Mord Omer and Prof. Andrei Brezhnoi from the Technical University of Munich.
