Hong Kong scientists create DNA-modified salmonella bacteria for treating cancer

In a major breakthrough, scientists at Hong Kong University have succeeded in creating DNA-modified salmonella bacteria that could help in treating cancer cells, without damaging the healthy cells.

Salmonella bacteria are mostly found in inadequately cooked meat, raw egg and egg products. Researchers at the University of Hong Kong used engineering and synthetic biology to turn salmonella into YB1, an anaerobe bacterium which grows and reproduces only in oxygen-free environments - like inside solid tumours.

In a trial on mice, the scientists showed YB1 could colonise the tumour and suppress cancer metastasis. In a model of breast cancer, it reduced tumour growth by 50%. In a liver cancer model, it suppressed growth by 90%. The bacterium was also able to suppress the growth of other solid tumours, for example, neuroblastoma.

The researchers now aiming to develop the new altered salmonella as a tumour-targeting agent in the near future. Scientists said they have filed patent applications in different countries and have already received a patent from the United States Patent and Trademark Office.

Professor Jiandong Huang, who led the research programme, said YB1 can be viewed as a "guided missile" that can deliver "destructive warheads to the tumour tissue by means of delivering therapeutic proteins and drugs, resulting in tumour regression".

He added that 26% of mice treated with YB1 bacterium in the breast cancer mouse model showed complete regression of tumours. The ones treated with the bacterium were also able to survive during the whole experiment which lasted for four weeks after treatment, compared to the mice in the control group that died on around Day 15.

The professor noted that YB1 is expected to be ready for clinical trials in a few years.