Treating Prostate Cancer With PARP Inhibitors
The risk of breast cancer increases with mutations in the gene BRCA2. An alteration in the same gene has been found to be linked with prostate cancer. The way prostate cancer develops due to change in the BARC2 gene is same as the way breast cancer develops due to change in BARC2 gene. This altered gene is found to increase the tumor growth in prostate glands of men. Research carried out on mice by The Institute of Cancer Research at its Breakthrough Breast Cancer Research Center has shown that lack of BRCA2 gene in prostate gland resulted in certain genetic changes that increase the risk of prostate cancer over time. The scientists examined the prostate cells of the mice that are devoid of BRCA2 gene that plays role in DNA repair. The cells lacking BRCA2 gene failed to repair the damaged DNA and it resulted in accumulation of DNA errors over time. Though direct effect is not found immediately due to these DNA errors, they may result in damage of the anti-tumor genes over a period of time and thus, they encouraged the growth of tumors in prostate cells.
To justify the above research, scientists induced alterations in another gene termed p53 which is found to be missing in more than half of the cancer cells. Alteration of the p53 gene along with BRCA2 gene resulted in increased DNA damage which in turn increased the risk of developing cancer.
PARP inhibitors are found to give promising results in treating breast cancer in woman with altered BRCA2 gene. So, this discovery of BRCA2 gene in prostate cancer laid foundation for studies to find out the role of PARP inhibitors in treatment of prostate cancer caused due to genetic changes in BRCA2 gene. The relationship between the breast cancer and prostate cancer caused by altered BRCA2 gene helped in identifying the overlapping areas of the two cancers where similar treatment can be used to treat them.
The research carried out at The Institute of Cancer Research have shown that PARP inhibitors gave positive results in treating advanced stages of prostate cancer. However, it has to be supported by further research on more number of patients to know if it can be used efficiently in men with prostate cancer without the danger of side effects.
The PARP inhibitors were also found to regulate the prostate cancers that developed due to rearrangement of two genes TMPRSS2 and ERG. It was therapeutically hard to regulate the effects of this gene combination. But, the PARP inhibitors were able to regulate this gene duo. Research work shows that a great number of prostate cancer patients can get benefited from PARP inhibitors.
Studies on cell lines and mice with prostate cancer have shown that PARP inhibitor Olaparib regulated the growth of tumors resulting from TMPRSS2and ERG gene. It even prevented the tumor from spreading to other parts. However, Olaparib remained ineffective on tumors that did not show the gene fusion.
Lastly, scientists are still working to find out more about the working of PARP inhibitors in regulating the prostate, ovarian and breast cancers.