Researchers at the University of Bradford in the UK are pinning their hopes on a locally activated cancer treatment as a means of destroying solid tumours without damaging healthy tissue.

In preclinical trials, the enzyme-triggered version of colchicine, a compound usually regarded as too toxic to be used as an anticancer agent, was applied to five different types of cancer (breast, colon, lung, sarcoma and prostate) with no observed adverse effects, reported the researchers from the University of Bradford’s Institute for Cancer Therapeutics (ICT).

In one study, half of the mice treated showed complete tumour remission after a single dose, they added. The ICT team is now in discussions with a funding source on taking the drug through the final stages of preclinical assessment, after which the plan is to start clinical trials at St James’s University Hospital in Leeds.

The new delivery mechanism uses a metalloproteinase (MMP) known to be active at high levels environments in tumour environments to target the colchicine at blood vessels in solid tumours without causing toxic side-effects.

“One role of this particular MMP in cancers is to dig a path for the tumour to grow bigger and develop new blood vessels that will help nourish the tumour,” explained  ICT director Professor Laurence Patterson.

“Our novel delivery method uses the presence of this active MMP to activate the drug which attacks and breaks down cancer blood vessels, destroying the tumour’s lifeline.”

Targeted directly

Professor Patterson described the approach as a form of “smart bomb” that could be targeted directly at any solid tumour without appearing to harm healthy tissue.

Using MMP activity as a trigger should also open the door to colchicine treatment of secondary tumours, while the same mechanism could deliver other drugs directly to tumour sites, the ICT team believes.

Colchicine is a natural compound derived from the Autumn crocus. It is used selectively as an anti-inflammatory agent to treat gout and Behçet’s disease.

Professor Patterson and his team are supported by a Programme Award from local charity Yorkshire Cancer Research for the discovery and development of new anticancer drugs.