Researchers at Karolinska Institutet report in the Journal of Experimental & Clinical Cancer Research that sodium selenite not only can damage tumour cells but also influence characteristics linked to tumour aggressiveness and treatment response. The findings are based on both cell experiments and analyses of tumour tissue from patients with pancreatic cancer.
Pancreatic cancer is one of the most difficult cancers to treat. One contributing factor is that tumour cells are highly adaptable and can change their characteristics. This ability has been linked to an increased capacity for tumour spread and resistance to treatment.
In the current study, researchers investigated whether sodium selenite, a form of the trace element selenium that has previously been shown to damage cancer cells, could also influence tumour cell characteristics in pancreatic cancer. The study included three laboratory models of the most common type of pancreatic cancer, as well as tissue samples from ten patients who had undergone surgery for the disease. The work was led by first author Ozan Aricak , a doctoral student at the Department of Laboratory Medicine .
Photo: The Swedish Cancer and Allergy Foundation
Mikael Björnstedt , professor at the Department of Laboratory Medicine and the study’s senior author, explains the significance of the findings.
“We show that selenite can not only damage tumour cells but also influence their characteristics and how they change over time. This gives us a broader understanding of how the substance acts in pancreatic cancer and may help us identify which tumours are most likely to respond to treatment.”
The results showed that the effects of selenite varied depending on the dose and the type of tumour tissue. In some cancer cells, changes were observed that suggested the cells acquired less aggressive characteristics. In tissue samples from patients, the higher dose caused more extensive tumour cell damage. At the same time, signs were seen that the cancer cells developed less aggressive characteristics, particularly in the parts of the tissue that contained tumour cells.
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“One strength of the study is that we were able to investigate the same biological question at several levels, from changes in tissue visible under the microscope to changes in proteins and genes. This provided a more comprehensive picture of how selenite affects tumours in models that resemble what is seen in patients,” says Tímea Szekerczés , postdoctoral researcher at the Department of Laboratory Medicine and one of the joint last authors.
The researchers emphasise that the study was conducted in experimental models and that the results therefore do not demonstrate any clinical treatment effect in patients. The number of patient samples was also limited, meaning that some analyses could only be performed on a smaller subset of the material.
The study was conducted through close collaboration between research and clinical pathology groups at Karolinska Institutet and Karolinska University Hospital. The work was jointly driven by the research groups of Mikael Björnstedt and Jonas Fuxe, with important contributions from Carlos Fernández Moro, Wenyang Shi, Mehran Ghaderi and Joakim Dillner, among others. The FENO Core Facility at Karolinska Institutet also provided support for multiplex immunofluorescence analyses.
As a potential conflict of interest, the researchers disclose that Mikael Björnstedt is an inventor on a patent application concerning the intravenous use of inorganic selenium in cancer treatment and holds shares in SELEQ OY. According to the authors, these interests did not influence how the study was conducted or how the results were interpreted. The remaining authors declare no competing interests.
Publication
Aricak O, Shi W, Moro CF, Ghaderi M, Dillner J, Fuxe J, Björnstedt M, Szekerczés T
J Exp Clin Cancer Res 2026 Jul;45(1). DOI: 10.1186/s13046-026-03778-4
