New weapon against ovarian cancer: radioimmunotherapy eliminates cancer stem cells
Scientists at the Paul Scherrer Institute in Switzerland have developed an innovative radioimmunotherapy that effectively eliminates ovarian cancer stem cells in preclinical studies. The isotope Terbium-161 (¹⁶¹Tb) proved more effective than the previously used Lutetium-177, opening a new chapter in the fight against resistant cancers. The results of this work were published in the July issue of The Journal of Nuclear Medicine.
Cancer stem cells (CSCs) are particularly difficult to eliminate – they can self-renew, cause disease relapse, metastasis, and resistance to treatment. They are often the cause of treatment failure and poor prognosis. Therefore, researchers have been searching for years for methods that will precisely target and destroy these cells.
Although immunotherapies targeting CSCs had been previously tested, their effectiveness still left much to be desired. Now, there is hope for a real breakthrough.
A team of scientists from the Center for Radiopharmaceutical Sciences of the Paul Scherrer Institute in Switzerland has proposed a new method of combating CSC – radioimmunotherapy based on the isotope Terbium-161.
“Radioimmunotherapy enables precise, targeted delivery of particulate radiation to tumor antigens while minimizing off-target accumulation and increasing tumor retention and irradiation, making it a promising choice for cancer stem cell treatment,” explains Dr. Jürgen Grünberg, senior scientist in the research team.
In the study, the scientists compared two types of radioactive immunoconjugates:
– ¹⁷⁷Lu-DOTA-chCE7 (using Lutetium-177)
– ¹⁶¹Tb-DOTA-chCE7 (using Terbium-161)
Both molecules were designed to recognize specific biomarkers of ovarian cancer stem cells—L1CAM+ and CD133+. Testing was performed first in vitro and then in mice implanted with ovarian tumors.
The results were clear: “¹⁶¹Tb-DOTA-chCE7 showed significantly increased cytotoxicity compared to ¹⁷⁷Lu-DOTA-chCE7, eliminating all ovarian CSCs and tumor cells isolated from CSCs in vivo,” the authors report.
The use of the Terbium-161 isotope has enormous potential because – in addition to beta-minus particles – it also emits Auger electrons and very short-range conversion radiation, which increases the precision of destroying cancer cells.
“This is a breakthrough step towards implementing Terbium-161-based therapies into clinical applications,” emphasizes Dr. Tihomir Todorov, co-author of the study.
According to scientists, Tb-161-based therapies could find applications in personalized oncology, helping not only to eliminate resistant cells but also to improve diagnosis and monitoring of treatment progress.
Source: The Journal of Nuclear Medicine, July 2025.
politykazdrowotna
