- Scientists have found that a rabbit virus, myxoma, can act on human multiple myeloma cells and eliminate them.
- 25% of mice were rid of multiple myeloma on treatment with myxoma.
- 65% of mice showed reduction in cancer after treatment with myxoma.
The introduction of the
myxoma virus (MYXV) onto multiple myeloma (MM) cells by a research team from
Medical University of South Carolina (MUSC) showed that there was an elimination
of most of the malignant cells. The study published in the
Molecular Therapy - Oncolytics described how the
introduction of MYXV led to a strong reaction from the immune system that
completely removed the disease in animals.
Multiple MyelomaMultiple myeloma is a type of blood cancer, which is found to develop in the plasma cells present in the bone marrow. The plasma cells are responsible for the development of antibodies that are vital for the maintenance of a healthy immune system.
The affected plasma cells are termed myeloma cells and they lead to the production of abnormal antibodies called M proteins. These M proteins are the hallmark characteristic associated with multiple myeloma. The myeloma cells are all identical to each other and they result in symptoms such as bone damage or kidney proteins. This is one of the most difficult to treat cancers, even all the new regimens of chemotherapy. Most patients are found to succumb to the disease when they become resistant to the chemotherapy treatment or due to reinfusion of cancer cells during stem cell transplant.
Viral OncolyticsIn the quest to identify a new approach that would provide an effective treatment for multiple myeloma, Dr. Eric C. Bartee, who is an assistant professor of Microbiology and Immunology at MUSC, along with his colleagues used viral oncolytics to solely target and destroy the target cancer cells. The highlight of the study has been that the use of these oncolytics resulted in the destruction of the cancer cells but with no sign of relapse.
The current study has been the result of several years of study by Dr. Bartee who has been using the myxoma virus to destroy multiple myeloma cells in culture. This virus, in nature, affects only rabbits and is not infectious to humans. However, when this virus was added to the multiple myeloma cancer cell lines, it was found to kill human multiple myeloma cell lines.
Stem Cell TransplantStem cells of the patient are often used to treat multiple myeloma patients but they have a high chance of relapsing into cancer due to the presence of cancer cells in the stem cells. Studies have shown that treating these stem cells with the myxoma virus aided in eliminating multiple myeloma cells, a technique that was carried out prior to administration to the patients. This would, therefore, prevent relapse.
Systemic Treatment with Myxoma VirusThe scientists wondered if the successful removal of the multiple myeloma cells from the stem cells would ensure destruction of the cancer cells beyond the concept of transplantation. When the MYXV was introduced as a systemic treatment, it resulted in
- 66% of mice showed decrease in disease progression.
- 25% of mice showed complete elimination of disease with no sign of relapse.
Host Immune SystemThe MYXV is a rabbit virus and is not found to replicate in the human multiple myeloma (MM) cells, the elimination of cancer could be due to the immune system of the host. The bone marrow was unaffected by the introduction of the virus.
This showed that
- The immune system of the host remained functional
- It could fight against the cancer
- Administration of MYXV increased CD8+ cells
- The large scale production of this virus
- Demonstrating a high response rate in human studies
Resistance to TherapyPatients who undergo many cycles of chemotherapy may develop resistance but it is very difficult for multiple myeloma patients to develop resistance to the virus.
Dr. Bartee further added that this form of therapy increased the chances of survival which could prove to be useful in the therapy for multiple myeloma.
The non-traditional method of therapy needs to undergo extensive testing and trials before it enters mainstream therapy, but the hope of an effective treatment method is significant.
- What is Multiple Myeloma? - (https://www.themmrf.org/multiple-myeloma/what-is-multiple-myeloma/)
- Eric Bartee, Mee Y Bartee, Bjarne Bogen, Xue-Zhong Yu. Systemic therapy with oncolytic myxoma virus cures established residual multiple myeloma in mice. Molecular Therapy Oncolytics, 2016; 3: 16032 DOI: 10.1038/mto.2016.32