Nerve cancer: discovered cause of therapy resistance

Special cells release active substance from the tumor

Brain Tumor © National Cancer Institute
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Neuroblastoma, a tumor of the nervous system, is one of the most common childhood cancers. If it is recognized early, the chances of recovery are good, but if the tumor has already spread, only about a quarter of the children can be cured. Now scientists have discovered why some tumor cells do not respond to chemo: they pump out the drug delivered through the bloodstream out of the tumor. They now want to develop a therapy method that specifically combats these cells and thus improves the effect of chemotherapy.

"So-called SP cells can lead to therapy resistance in neuroblastoma because they remove the chemotherapeutic agents from the cell, " explains Dr. med. Charlotte Hirschmann-Jax, Director of the research project at the University Children's Hospital Düsseldorf. "These cells form a special cell group in the tumor and are probably also responsible for its growth: As so-called tumor stem cells, they grow very fast and can produce new cancer cells." The abbreviation "SP" stands for "side population", since the cells in the pictorial representation after staining form a marginal tail adjacent to the remaining cells.

Transport blockade wanted

"In more than two-thirds of neuroblastoma patients whose disease recurred after therapy, we discovered SP cells, " reports Hirschmann-Jax. This is the first time that her group has demonstrated such resistant cells in neuroblastoma. Now scientists want to explore and block the transport mechanism for the chemotherapeutic agents in the SP cells, so that the cancer drugs can remain in the cells and develop their effects.

As target structure, the researchers are already targeting special surface molecules of SP cells. These are transport proteins that are increasingly found on the cells. They are probably the actual "pumps" of SP cells. "Targeted blockade of these transport aids could thus indirectly increase the effect of chemotherapy, " hopes Hirschmann-Jax.

This would reduce the growth of cancer and stop the dangerous spread of degenerated nerve cells. Since other cells, such as the breast or lung, also have cells with the properties of SP cells, their unusual behavior is also of general importance for tumor biology research and clinical practice. display

(German Cancer Aid, 31.05.2006 - NPO)