Recurrent breast cancer patients urgently need new therapies to improve their quality of life. Existing therapies often cause debilitating side effects that severely degrade their quality of life. Oncolytic viruses develop a therapeutic modality that allows it to selectively destroy tumor cells. Oncolytic agents such as herpes simplex virus, vaccinia virus, measles virus, and many others are in general clinical trials for several cancers to demonstrate safety and efficacy. For oncolytic virothearpy to be adopted, it must first show it can eliminate metastatic diseases. Scientists have begun “arming” oncolytic viruses by giving the virus anticancer transgenes (genetic material that has been transferred naturally). By doing so, the virus is able to target tumor environments and inhibit angiogenesis in those areas. In addition, to further enhance viral efficacy the oncolytic agent is given immune-stimulating factors. When the oncolytic agent is given an anticancer transgene and immune-stimulating factor, the virus effectively inhibits growth and metastases of breast cancer. Other studies show if oncolytic viruses are used with other therapeutic strategies, tumor cell apoptosis increases. In addition, combination therapy is shown to inhibit breast cancer cell growth. The way in which the oncolytic agents are delivered is also very important to understand. When administering oncolytic virotherapy intravenously it was noted that the virus mediated tumor growth suppression quicker and within that specific area. In addition, it was seen that primary tumors were completely eliminated when oncolytic viruses were administered. Even though many clinical trials are in progress to further support oncolytic viral therapy, caution must be taken to not interpret these findings incorrectly. Oncolytic therapy must be tested on a case-to-case basis with consideration of the the cell line, the virus, timing, and mechanism. However, their is hope that oncolytic therapy will work for individuals with recurrent cancer.
Quite honestly, I did not know this was a possible cancer treatment. But, it seems logical because viruses inject their DNA into the cell’s DNA. I found a study that suggests that there are two approaches to administering this treatment. The first one is through an I.V., which is aimed at the tumor itself. The second is releasing a tumor antigen to “mop up” the remaining cancerous/tumor cells. One of the major hurdles for this therapy is to correctly dose the virus. This study suggested that there needs to be a sufficient concentration of the virus in order to target the tumorous cells. It is truly amazing to see how medicine has evolved over time. Medicine will continue to advance, so it will be interesting to see what new treatments come out in the future.
ReplyDeleteThe study can be found here: https://www-sciencedirect-com.dml.regis.edu/science/article/pii/S1879625715000942#
Through a study done by Wennier, Liu, & McFadden, it was seen that the Oncolytic Virotherapy (OV) in combination with chemotherapy, each with their own distinct anti-tumor reducing agents results in greater therapeutic effects than either treatment alone. In order for patients to obtain the maximum benefits from these combination treatments, a better understanding of the mechanism(s) that lead to the cooperative interactions between chemotherapy drugs and OVs are required, including also a more complete understanding of the mechanisms of tumor cell killing that occur during chemotherapy and Oncolytic Virotherapy monotherapies. Looking at this combination therapy through a mechanistic viewpoint, it is possible that the cooperative interactions that are detected between OVs and chemotherapy drugs are due to the improvement of oncolytic pathways that was observed within the individual treatments, or another mechanistic reason could be that activation of certain pathways may occur only when triggered by a combination of these two treatments. But if we can get OV to work independently of chemotherapy it would allow for more tailored cancer treatments for patients, without the harm of multiple drug usage in chemotherapy.
ReplyDeleteWennier, S. T., Liu, J., & McFadden, G. (2012). Bugs and drugs: oncolytic virotherapy in combination with chemotherapy. Current Pharmaceutical Biotechnology, 13(9), 1817–1833. Retrieved from http://dml.regis.edu/login?url=http://search.ebscohost.com/login.aspx?direct=true&db=cmedm&AN=21740354&site=ehost-live&scope=site