Non-invasive imaging of PI3K/Akt/mTOR signalling in cancer.

Platinum based drugs are widely used to treat various types of cancers by inducing DNA damage mediated cytotoxicity. However, acquirement of chemoresistance towards platinum based drugs is a common phenomenon and a major hurdle in combating the relapse of the disease. Oncogenesis and chemoresistance are multifactorial maladies which often involve deregulation of one of the prime cell survival pathways, the PI3K/Akt/mTOR signalling cascade. The genetic alterations related to this pathway are often responsible for initiation and/or maintenance of carcinogenesis. Molecular components of this pathway are long being recognized as major targets for therapeutic intervention and are now also have emerged as potential tools for diagnosis of cancer. To develop novel therapeutics against the key molecules of PI3K pathway, stringent validation is required using both in-vitro and in-vivo models. Repetitive and non-invasive molecular imaging techniques, a relatively recent field in biomedical imaging hold great promises for monitoring such diagnosis and therapy. In this review, we first introduced the PI3K/Akt/mTOR pathway and its role in acquirement of chemoresistance in various cancers. Further we described how non-invasive molecular imaging approaches are sought to use this PI3K signalling axis for the therapeutics and diagnosis. A theranostic approach using various imaging modalities should be the future of PI3K signalling based drug development venture.