Cookie Settings

We use cookies to optimize our website. These include cookies that are necessary for the operation of the site, as well as those that are only used for anonymous statistic. You can decide for yourself which categories you want to allow. Further information can be found in our data privacy protection .


These cookies are necessary to run the core functionalities of this website and cannot be disabled.

Name Webedition CMS
Purpose This cookie is required by the CMS (Content Management System) Webedition for the system to function correctly. Typically, this cookie is deleted when the browser is closed.
Name econda
Purpose Session cookie emos_jcsid for the web analysis software econda. This runs in the “anonymized measurement” mode. There is no personal reference. As soon as the user leaves the site, tracking is ended and all data in the browser are automatically deleted.

These cookies help us understand how visitors interact with our website by collecting and analyzing information anonymously. Depending on the tool, one or more cookies are set by the provider.

Name econda
Purpose Statistics
External media

Content from external media platforms is blocked by default. If cookies from external media are accepted, access to this content no longer requires manual consent.

Name YouTube
Purpose Show YouTube content
Name Twitter
Purpose activate Twitter Feeds

How resistance to important cancer drugs develops

No. 35c | 23/07/2019 | by Koh

Taxanes, frequently used anti-cancer drugs, block cell division and thereby drive tumor cells into cell death. However, therapy resistance often develops in the course of the treatment. Scientists from the German Cancer Research Center have now discovered how cancer cells degrade a protein that induces cell death in cases of failed mitosis. If this tumor brake is missing, the cancer cells survive and are resistant to the effect of taxanes.

Many Cancer drugs act on the microtubules of the mitotic spindle (green).
© Afunguy, Wikipedia

Before cells divide, they must first ensure that their genetic material is correctly distributed to both daughter cells. To achieve this, they build up a bundle of special protein microtubules known as mitotic spindle because of its characteristic shape. The microtubules of the spindle pull the individual chromosomes in an ordered fashion to the opposite poles of the cell and are then normally degraded.

Many classical anti-cancer drugs act on the spindle microtubules: The taxanes originally obtained from the yew, for example, prevent the degradation of the microtubules and thus stabilize the mitotic spindle. As a result, the cancer cells remain stuck in cell division. Normally, this triggers cell death.

"But after prolonged administration of these drugs, cancer cells can escape the mitosis stop, return to the cell cycle and continue to divide - and thus develop resistance to chemotherapy with taxanes," explains Ingrid Hoffmann from the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ).

In her current work on cancer cell lines, the scientist and her team therefore investigated the protein FBXW7, which is responsible for mitosis stop-induced cell death. FBXW7 is therefore considered a tumor suppressor gene. The researchers found that the longer the mitosis stop lasts, the more FBXW7 concentration in the cancer cells decreases.

On closer examination, the scientists found that the FBXO45-MYCBP2 protein complex attaches to FBXW7 during the mitosis stop. This complex is part of the cell's recycling system: it attaches the signal molecule ubiquitin to other proteins and labels them for degradation. This reduces the amount of FBXW7 available and the cancer cells escape cell death.

Using micro-RNAs, the researchers were able to genetically block the FBXO45-MYCBP2 complex and thus stop the degradation of the tumor suppressor. This leads to increased tumor cell death and prevents the development of resistance.

"This is the first time that we have described a surprising connection between protein degradation and the development of resistances against taxanes and other drugs that act on the spindle microtubules," said Hoffmann. "Our result may possibly contribute to the development of more effective drug treatments in the future that circumvent this form of resistance."

Kai T. Richter, Yvonne T. Kschonsak, Barbara Vodicska and Ingrid Hoffmann: FBXO45-MYCBP2 regulates mitotic cell fate by targeting FBXW7 for degradation.
Cell Death and Differentiation 2019, DOI: 10.1038/s41418-019-0385-7

With more than 3,000 employees, the German Cancer Research Center (Deutsches Krebsforschungszentrum, DKFZ) is Germany’s largest biomedical research institute. DKFZ scientists identify cancer risk factors, investigate how cancer progresses and develop new cancer prevention strategies. They are also developing new methods to diagnose tumors more precisely and treat cancer patients more successfully. The DKFZ's Cancer Information Service (KID) provides patients, interested citizens and experts with individual answers to questions relating to cancer.

To transfer promising approaches from cancer research to the clinic and thus improve the prognosis of cancer patients, the DKFZ cooperates with excellent research institutions and university hospitals throughout Germany:

  • National Center for Tumor Diseases (NCT, 6 sites)
  • German Cancer Consortium (DKTK, 8 sites)
  • Hopp Children's Cancer Center (KiTZ) Heidelberg
  • Helmholtz Institute for Translational Oncology (HI-TRON Mainz) - A Helmholtz Institute of the DKFZ
  • DKFZ-Hector Cancer Institute at the University Medical Center Mannheim
  • National Cancer Prevention Center (jointly with German Cancer Aid)
The DKFZ is 90 percent financed by the Federal Ministry of Education and Research and 10 percent by the state of Baden-Württemberg. The DKFZ is a member of the Helmholtz Association of German Research Centers.


Subscribe to our RSS-Feed.

to top
powered by webEdition CMS