Researchers at the São Paulo State Cancer Institute (ICESP) in Brazil explored a new approach to treat prostate cancer
Prostate cancer is the most common type of cancer in men. When the tumor is localized, the 5-year survival rate of patients is close to 100%, dropping to 31% in the case of cancer that has spread to other parts of the body. The first gene therapy experiment approved by the FDA occurred in 1990; since then, researchers are using this approach to create new cures for a variety of conditions, including cancer. Gene therapy consists of techniques that aim at manipulating genes within specific targets, such as cancer cells. Scientists at the São Paulo State Cancer Institute (ICESP) in Brazil tested a new gene therapy approach for prostate cancer. Their results were recently published in Gene Therapy.
Previous gene therapy alone could not completely stop tumor progression
In their previous work, researchers at the Brazilian institute created a gene therapy approach to treat prostate cancer. The scientists genetically manipulated a virus so that it could no longer cause disease. They also modified the virus to contain p53, a gene with a strong anti-tumor function. The injection of the virus into the tumor allowed it to infect and transfer the anti-tumor gene into cancer cells. The functioning of p53 gene would then cause the death of malignant cells. However, experiments revealed that this method could not completely stop tumor progression. In their most recent work, the researchers tried to improve the effectiveness of gene therapy by combining it with chemotherapy. They treated mice carrying prostate cancer cells with gene therapy combined with one of three drugs, namely mitoxantrone, docetaxel, and cabazitaxel, and compared these mice with mice who did not receive treatment.
Combination therapy is advantageous in the treatment of prostate cancer
The experiments revealed that a combination of gene therapy with either mitoxantrone or docetaxel did not provide advantages over either therapy alone. However, a combination of cabazitaxel and gene therapy proved effective and completely blocked tumor progression in mice. Cabazitaxel is already used as a treatment for prostate cancer but comes with severe side effects, which are especially damaging to the immune system. In their experiments, the scientists used a lower dose of cabazitaxel in their combination with gene therapy. The lower dosage of the drug reduced the side effects, yet was enough to block tumor progression. The research group is now working to refine this therapeutic approach even further. The researchers are aiming to develop gene therapy for prostate cancer that can kill malignant cells, while at the same time stimulate the immune system to attack the tumor as well, for improved overall efficiency.
Written by Raffaele Camasta, PhD
Amer, M. H. (2014). Gene therapy for cancer: present status and future perspective. Molecular and Cellular Therapies, 2(27).
Genetically modified virus combats prostate cancer. https://www.eurekalert.org/pub_releases/2019-06/fda-gmv062619.php
Tamura, R. E., Lana, M. G., Costanzi-Strauss, E., & Strauss, B. E. (2019). Combination of cabazitaxel and p53 gene therapy abolishes prostate carcinoma tumor growth. Gene Therapy.