Posted by: Glow-worm PJ3 JUN 2014
Glioblastomas are tumours arising from star-shaped cells called astrocytes, which make up the supportive tissue of the brain. They are highly malignant because the cells divide quickly and are supported by a large network of blood vessels. They also have finger-like tentacles that make complete surgical removal almost impossible, and treatment has traditionally consisted of a combination of surgery, chemotherapy and radiotherapy.
A recently developed method of tumour treatment is virotherapy, in which tumour cells are infected with viruses and are overwhelmed by viral infection and cell lysis, spreading the viral infection to adjacent malignant cells.
The herpes simplex virus has shown potential as an agent in glioblastoma virotherapy, as it naturally infects human brain cells. The virotherapy follows surgical tumour reduction, but suffers from the problem of keeping the virus at the site of the tumour removal for long enough to have its effect. First, the body’s immune response attacks and kills the virus, and secondly, the cavity left following tumour removal fills with cerebrospinal fluid, flushing the virus from the site.
Scientists at Harvard Stem Cell Institute devised a potential solution by incorporating mesenchymal stem cells (MSCs) into a gel that is then applied to the post-operative site. MSCs give rise to bone marrow and are attractive as drug delivery vehicles because they trigger a minimal immune response and can act as a carrier for the oncolytic virus, in this case herpes simplex. The cells were encapsulated into a biocompatible gel and applied directly to the tumour site in a mouse model.
Imaging proteins were used to monitor the effectiveness of the technique, and it was found that the gel kept the stem cells alive for longer, allowing the virus time to replicate and kill any residual cancer cells not removed by the debulking surgery. Research is ongoing, and hopes are high for the potential of this novel, relatively side-effect free, therapy.