In 2008, an estimated 12.7 million new cases of cancer occurred worldwide according to Cancer Research UK. In women breast cancer accounts for almost a quarter of these; in men lung cancer is most common. The challenge for medical professionals is finding the most suitable way to selectively target any one of the more than 200 different types of cancer while minimizing any harmful secondary effects of treatment (such as radiation exposure and immunosuppression).


Now a research team, headed by Prof. Chae-Ok Yun from the Department of Bioengineering at Hanyang University, is using gene therapy to selectively target and kill cancer cells with minimal side effects. Cancer gene therapy uses DNA as a pharmaceutical agent to treat the cancer. Prof Yun’s team uses a genetically engineered virus to preferentially infect and reproduce inside tumour cells, finally bursting the cells and therefore killing them, a so called ‘oncolytic virus’. (fig. 1)

Figure 1: Gene therapy using an Adenovirus vector

 

In particular, Prof. Yun’s team has been working with oncolytic adenovirus (Ad). Oncolytic Ads specifically destroy cancer cells without harming normal cells and reproduce thousands of copies within their host cells. However, because the oncolytic antitumor activity is insufficient to effectively eliminate tumours, various strategies have been devised to improve the therapeutic efficacy. One way is to ensure the therapeutic gene containing virus can freely replicate thereby increasing the effects of anti-tumour agents (fig 2)

 

Figure 2: Choi et al., Advanced Drug Delivery Reviews, 64 (2012) 720-729

Prof Yun’s team is also utilizing nanotechnology to improve the Ads success. In order to eradicate cancer, not only is it essential to detect tumour tissues early (and ideally via a non-invasive route), but doctors also need to know whether the cancer has spread to other parts of the body (its metastatic state). Since nanoparticles possess unique physicochemical properties, a single particle can be designed to act as a multifunctioning molecular imaging probe and as a carrier to deliver anti-cancer agents to tumours.
So called ‘smart Ad nanocomplexes’ have been evolved by modifying the Ad surface with a nonviral system such as polymers and nanoparticles which enables the Ad to remain in the bloodstream for longer, giving it more time to reach tumour cells, before being removed and recycled by the bodies’ own waste recycling systems in, for example the liver (where hepatocytes and Kuppfer cells break down waste and red blood cells).
Prof Yun and her bioengineering team have been perfecting the design and function of these nanoparticles to allow detection as well as monitoring of cancer patients at an early-stage. Real-time, non-invasive monitoring of the theragnostic nanoparticles enables clinicians to rapidly decide whether a particular treatment regimen is effective in a patient or not.
The research team has already finished a phase I clinical trial against recurrent solid tumours and is now working on a phase II clinical trial against head and neck cancer

 

 

 
For more information contact:
Prof. Chae-Ok Yun
Department of Bioengineering
Hanyang University
Email: chaeok@hanyang.ac.kr