New cancer therapy: with viruses against tumors
Viruses could make a significant contribution to cancer therapy in the future. Researchers at the German Cancer Research Center (DKFZ) in Heidelberg are working on a method to use viruses to fight tumor cells.
The DKFZ scientists hope to use viruses to develop a new approach to cancer therapy. "The basic idea of virotherapy is as follows: Viruses are made to do what they are professionals at, namely to destroy human cells," explained Heidelberg molecular biologist Dirk Nettelbeck to the "dpa" news agency. If the viruses can be modified so that they destroy cancer cells but do not attack the healthy cells, the new method could revolutionize cancer therapy.
Viruses help in the fight against cancer The DKFZ has been working on the development of so-called oncolytic viruses for the treatment of cancer for a long time. Already in 2004 experts from the DKFZ reported that promising results in the elimination of chemotherapy-resistant tumors were achieved in preclinical studies with the help of oncolytic herpes simplex viruses. According to the DKFZ researchers, the treatment approach of virotherapy can be traced back to observations by doctors who found that tumors regressed in cancer patients who simultaneously suffered from viral diseases. The destruction of the tumor cells "was only observed in isolated cases", but made it clear that "In principle, viruses can have a very good activity against tumors," emphasized the molecular biologist Nettelbeck. "We molecular biologists now have to change these viruses so that they only destroy cancer cells, but leave the healthy cells alone," Nettelbeck described the current joint research approach of the dermatological clinic in Heidelberg and the German Cancer Research Center.
Virotherapy as a new treatment method against cancer The cancer cells are to be attacked and destroyed directly with the help of virotherapy, whereby the viruses can be injected either directly into the tumor or into the bloodstream, Nettelbeck explained the approaches of the new treatment method. In the body of the cancer patient or in the tumors, the viruses are supposed to multiply after the injection and only kill the cancer cells. The DKFZ scientists face several challenges in their research work. On the one hand, the viruses would have to be redesigned so that they do not affect healthy cells, on the other hand, a defense reaction of the organism should also be avoided. The scientists are examining several alternatives, such as temporarily blocking the immune system or reshaping the viruses so that they are not recognized by the immune system. "If you change the virus envelope, the viruses get a new structure" and with the new "dress" the natural defense reaction of the organism could be avoided. "However, this is a complex matter," emphasized molecular biologist Nettelbeck.
Cancer Cell Kill Immediately After Injection? With the new approaches to virotherapy, even small amounts of virus per cancer cell could be sufficient to destroy them efficiently, according to the DKFZ experts. Cancer cells can be expected to be killed just a few hours after the injection. If there are problems in the course of virotherapy, the medication available can be used to stop the virus replication at any time at short notice, according to the DKFZ. If a corresponding virus vaccine is successfully developed, the researchers hope - in addition to the direct effect of the viruses against the cancer cells - also a type of vaccination of the body, which could cause the body's immune system to fight cancer. Overall, cancer treatment with viruses would offer a good therapeutic alternative for tumors that cannot be surgically removed or have developed resistance to chemotherapy or radiation therapy, the DKFZ experts assessed their research approach. In addition, synergies from the combined therapy with viruses and standard treatments such as chemotherapy are conceivable. Experts have so far hardly been able to assess whether virotherapy can be sufficient as the only treatment method to successfully fight cancer. (fp)
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