Zurich/Basel (awp/ats) – One of the oldest heart medications, digoxin, could help prevent the formation of metastases in breast cancer. According to a study by the ETH Zurich, it actually reduces the clusters of tumor cells circulating in the blood.
Scientists from the Swiss Federal Institute of Technology Zurich (ETH Zurich), the university hospitals of Basel and Zurich as well as the Basel-Landschaft Cantonal Hospital have discovered that this heart medicine based on digitalis – formerly extracted from foxglove – could also be effective in the context of breast cancer.
The authors of this study published Friday in the journal Nature Medicine carried out an extensive screening, systematically testing in recent years more than 2,400 different substances in cell cultures in order to find substances active against clusters of cancer cells originating from the primary tumor and circulating in the blood.
These cells (in English: circulating tumor cell/CTC) can group together in small groups (clusters) and implant themselves in other organs. This is the starting point for the formation of metastases.
“The formation of metastases in breast cancer depends on CTC clusters,” indicates the leader of the study, Nicola Aceto, professor of molecular oncology at ETH Zurich, quoted in a press release from the university.
Significant reduction
A first clinical study was carried out. Nine patients with metastatic breast cancer received safe, low-dose digoxin for one week. Result: the number of cells per cluster decreased significantly, on average by 2.2 cells.
Given the typical size of these clusters – up to a dozen cells – this meant a marked reduction in the risk of metastases. The smaller these clumps are, the less able they are to successfully metastasize.
-The experts also managed to elucidate the underlying mechanism: the Achilles heel of CTC clusters are the sodium and potassium pumps that are found in the membranes of tumor cells and which are responsible for transporting sodium out of the cells and potassium in cells.
Digoxin blocks these pumps and thus suppresses ion exchange. The cells therefore absorb more calcium from outside the cell membrane, which weakens the cohesion of the cancer cell clusters, which disintegrate.
Tested on other cancers
Laboratory tests have already been launched on other cancer diseases which are particularly dangerous due to the formation of metastases: cancers of the prostate, colon, pancreas and melanoma.
“This study should be considered a proof of concept showing that it is possible to interrupt CTC clusters,” Nicola Aceto told Keystone-ATS. To verify whether this approach really prevents metastases, we must first develop drugs that are more effective and easier to dose.
Digoxin has been used since around 1930 as the first effective drug for the treatment of chronic heart failure. In the meantime, digitalis preparations are rarely used anymore due to possible side effects.
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