Imagine - Symposium Abstract - Combining molecular imaging with spatiotemporally synchronized cancer combination therapy using photo-activated nanoparticle drug delivery systems to light up and selectively destroy cancer

Absorption of light by molecules within or associated with, cells and tissues creates photophysical and photochemical processes that are captured for diagnostics, surgical guidance, a treatment, and for gaining of simple mechanistic understanding of disease pathology.

Photodynamic therapy (PDT) is a photochemistry-based process resulting from the light activation of chemicals localized at anatomical sites of disease. It involves the excitation of certain chemicals, called photosensitizers (PS) by photons of a specific wavelength to produce reactive species that are toxic to cells The active molecular species produced by such a molecular excitation destroys biological targets in the vicinity. PDT is approved for specific clinical applications by regulatory agencies world wide and has inherent selectivity built in it. A small fraction of the excited state de-energizes via fluorescence thus providing an opportunity to use the same molecule for detection/diagnostics and therapy making the approach a theranostic one.

As with any therapy, PDT elicits molecular responses that can be exploited to enrich our arsenal of cancer treatment. This requires the development of novel combinations delivered at the right time and the right place and is often achieved best using nanotechnology where PDT serves not only as a treatment trigger but also as a drug release switch. This talk will introduce a new nanotechnology platform for cancer combination therapy that utilizes near infrared light activation not only for photodynamic damage but also as an extrinsic mechanism to initiate release of complimentary drugs to suppress dynamic bursts in molecular signaling networks that promote tumor cell survival and treatment escape.

The goal is to achieve co-delivery with concomitant activity of photodynamic, molecular inhibitor and chemotherapeutic agents, selectively within the tumor. This approach overcomes challenges in achieving synergistic interactions using sequential drug delivery, which is compromised by the differential pharmacokinetics of individual agents. If successful in humans, this new paradigm for synchronized, tumor-focused combination therapy could ultimately obviate the present use of chronic drug injection by increasing efficacy per cycle whilst reducing systemic exposure to toxic drugs.