Posted by: Sophie Khatib24 JAN 2013
My dissertation topic was looking at mTOR, the mammalian target of rapamycin, and how the presence of GLUT1, a glucose transporter, affected the response of cancer cells to a novel anticancer agent in order to establish how the drug worked and how cells reacted in the presence of this drug. It sounds quite complicated and to be honest, it was. It seems like only yesterday that I had papers covering my entire floor and was making myself an mTOR related dictionary, trying to work out what all the different words and pathways actually meant. Since then, it has become somewhat of a fascination for me – further developments in the characterisation of mTOR and factors affecting its role in the body are being published on a regular basis and they span a large number of topics and specialities but in the main, they are related to cancers.
I have recently found papers that are aiming to find if there is a link between disregulation of mTOR signalling and neuropsychiatric disorders such as autism. During my dissertation, I researched the role of mTOR in the body and what it does. Basically, it acts as a central regulator of a cells energy; sensing if there is enough energy and nutrients available to support cell proliferation.
Aberrant mTOR signalling during brain development results in brain abnormalities which could potentially lead to a range of problems including autism, epilepsy and cognitive disability to name a few. mTOR has a major role in the brain in helping to regulate the development of dendritic neurones and mutations in some of the proteins regulated by mTOR such as PTEN and TSC lead to an overactivated mTOR-PI3K pathway and this is the cause of the symptoms of neuropsychiatric disorders. Fragile X syndrome is the most common heritable form of intellectual disorder and it is thought that the main cause of this is dysregulated PI3K-mTOR pathway.
Rapamycin, and its analogues such as temsirolimus, could therefore theoretically be used to treat PTEN-associated autism and other disorders with the same pathology. It then poses the question, is it too late to treat when the patient starts to get symptoms, if the problem occurs during brain development or will drug treatment still help to control the symptoms? Are they the same isoforms and so will they respond to the same drugs as the dysregulated pathways in cancer biology? And does the dysregulated pathway in autistic patients put them at increased risk of other pathologies?
So many questions and so much research to be done!