An important part of choosing the most appropriate cancer therapy is understanding the malignancy of the tumor; however, current methods of assessing the malignancy of brain tumors are invasive and carry a high risk of complications. Collaborative research led by Professor Yasuchika Hasegawa and Professor Shinya Tanaka of Hokkaido University's Institute for Chemical Reaction Design and Discovery (WPI-ICReDD) has developed a non-destructive cancer grading detection system (GPS) that uses water-soluble luminescent europium complexes to assess the malignancy of model glioma tumor cells. This method can be used for non-invasive testing to determine the malignancy of a patient's tumor.

Describe the structural changes after the interaction between europium complex and tumor cells. Image source: MengfeiWang, etal. January 22, 2024Confocal microscopy image showing red light emitted by europium complexes within model glioma cells. White circles indicate aggregation of europium complexes. Source: Wang Mengfei et al., "Scientific Reports". January 22, 2024

The research team evaluated the malignancy of tumors by introducing europium complexes into model cells that mimic glioma. 26.3% of brain cancers (Source: CBTRUS). The researchers tested three different model cells simulating different levels of malignancy and measured changes in the lifetime of the europium complex's characteristic red light emission. The researchers found that within the first three hours after adding the europium complex, the more malignant cells experienced larger changes in their luminescence lifetime.

"Visualization of cancer cells using luminescent complexes has been reported before, but our hypothesis was that the photophysical signal emitted by this complex in cancer cells may reflect the internal information of the cancer cells," Hasegawa said.

Member of the research team at the Institute for Chemical Reaction Design and Discovery (WPI-ICReDD), Hokkaido University. From left to right Wang Mengfei, Tsuda Masumi, Tanaka Shinya, Hasegawa Yasuchika. Source: WPI-ICReDD

To achieve this result, the researchers first modified the europium complex so that it was soluble in water and stable in amino acids in the cell culture medium. Upon addition to the cell culture medium, the europium complex initially forms aggregates with itself. Upon interaction with model tumor cells, the aggregates fragmented into individual molecules, which were then rapidly taken up by the cells. This process causes the structure of the europium complex to change, resulting in a change in the lifetime of the complex's red light emission.

These differences in emission lifetimes are due to varying tumor activity and growth processes in different malignancy grades, which may lead to different structural changes in the europium complex on different time scales. The team anticipates that using this method can continuously detect tumor activity, providing doctors with critical information for deciding on appropriate treatment.

Tanaka explained: "In Japan, 4.6 people per 100,000 people suffer from brain tumors, and the 5-year survival rate for the most malignant grade 4 glioblastoma, an aggressive glioma brain tumor, is 16%. The malignancy assessment method we developed may benefit these patients in the future."

Compiled from /Scitechdaily