Deciphered cause of chemo-resistance in lung cancer
Experts say that lung cancer is the leading cause of cancer death in Europe. The treatment options for small-cell lung cancer in particular are very limited, especially since the tumors develop resistance to treatment with chemotherapy. Researchers have now unraveled the cause of this chemo-resistance.
Lung cancer is the leading cause of cancer death
Around one in four people in the European Union dies of cancer. Lung cancer is the leading cause of cancer death in Europe. Experts believe that around 85 percent of illnesses are related to tobacco use. Small cell lung cancer also affects smokers above all. The treatment of these tumors is particularly difficult because they can become resistant to chemotherapy. Researchers have now found the cause of this chemo-resistance.
Resistant to chemotherapy
Around 500,000 Germans are diagnosed with cancer each year. The result is usually surgery, radiation and / or chemotherapy. However, many cancer patients stop the therapy due to side effects.
And with some, the treatment often does not lead to success. For example, in many cases with small cell lung cancer. Because this cancer often leads to resistance to chemotherapy.
Austrian scientists have now found out why.
Survival is often only a few months
In advanced small cell lung cancer (SCLC), which primarily affects very heavy smokers, relapse with tumor recurrence that is resistant to further chemotherapy occurs about a year after successful treatment with cytotoxic chemotherapy and radiation.
The survival of those affected is usually only a few months. So far it was completely unknown what is responsible for it.
A team of researchers from the Medical University (MedUni) Vienna under the direction of Gerhard Hamilton (University Clinic for Surgery) has now found that circulating tumor cells merge and thus chemo-sensitive cells previously become chemoresistant cell assemblies.
Resistance of lung cancer cells to chemotherapy drugs decoded
Last year, the Austrian scientists reported in the "Trends in Cancer" magazine that they had decoded the resistance of lung cancer cells to chemotherapy drugs.
In a current communication from the university, Hamilton describes the processes: "The circulating tumor cells come together like a wagon castle to protect against chemotherapy and reduce the access of active substances."
These "aggregates" can comprise hundreds of thousands of cells, are up to two millimeters in diameter and are up to eight times resistant to chemotherapy drugs - on the one hand because hypoxia (lack of oxygen) forms inside the aggregate and on the other hand because these tumor cells reduce growth and thereby are less sensitive.
The current results have now been published in the scientific reports of the Nature Publishing Group.
30 years of ambiguity
These findings were made possible by the first-ever, permanent cultivation of circulating tumor cells from patients with advanced small cell lung cancer in Vienna.
The research group led by Hamilton and Robert Zeillinger (Molecular Oncology Group, University Clinic for Gynecology at MedUni Vienna) and Maximilian Hochmair (Otto-Wagner Spital) succeeded in developing seven cell lines from blood samples and then analyzing them in the laboratory.
"This is the first time after 30 years of ambiguity in this area that we have been able to decipher the causes of chemo-resistance," says Hamilton. In further studies, the scientists now want to find out how these cell groups can either be prevented or destroyed.
A promising approach, according to the MedUni Vienna expert, is to break up the cell mergers with the help of enzymes or inhibitors.
Lung cancer ranks first in cancer mortality among women
15 percent of people with lung tumors suffer from small cell lung cancer. At the time of diagnosis, SCLC has usually already metastasized and can no longer be operated on - the prognosis of those affected is accordingly poor.
The prospects become even worse if resistance to chemotherapy develops. "Those affected usually only survive a few months," says Hamilton.
“This is alarming given that lung cancer, the cause of death among women, has increased significantly over the past ten years, namely by 18 percent. In 2016, he replaced breast cancer as the cancer with the highest risk of death in women. ”
As reported by an international team of researchers at the beginning of the year, the lung cancer death rate among women rose again in Germany.
"Young people, but especially young women who smoke, should be aware of the high risk of developing SCLC along with other benign diseases," said Hamilton. (ad)